chan_dahdi.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2006, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief DAHDI for Pseudo TDM
 *
 * \author Mark Spencer <markster@digium.com>
 * 
 * Connects to the DAHDI telephony library as well as 
 * libpri. Libpri is optional and needed only if you are
 * going to use ISDN connections.
 *
 * You need to install libraries before you attempt to compile
 * and install the DAHDI channel.
 *
 * \par See also
 * \arg \ref Config_dahdi
 *
 * \ingroup channel_drivers
 *
 * \todo Deprecate the "musiconhold" configuration option post 1.4
 */

/*** MODULEINFO
   <depend>res_smdi</depend>
   <depend>dahdi</depend>
   <depend>tonezone</depend>
   <use>pri</use>
   <use>ss7</use>
 ***/

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 224337 $")

#ifdef __NetBSD__
#include <pthread.h>
#include <signal.h>
#else
#include <sys/signal.h>
#endif
#include <sys/ioctl.h>
#include <math.h>
#include <ctype.h>

#include <dahdi/user.h>
#include <dahdi/tonezone.h>

#ifdef HAVE_PRI
#include <libpri.h>
#endif

#ifdef HAVE_SS7
#include <libss7.h>
#endif

#include "asterisk/lock.h"
#include "asterisk/channel.h"
#include "asterisk/config.h"
#include "asterisk/module.h"
#include "asterisk/pbx.h"
#include "asterisk/file.h"
#include "asterisk/ulaw.h"
#include "asterisk/alaw.h"
#include "asterisk/callerid.h"
#include "asterisk/adsi.h"
#include "asterisk/cli.h"
#include "asterisk/cdr.h"
#include "asterisk/features.h"
#include "asterisk/musiconhold.h"
#include "asterisk/say.h"
#include "asterisk/tdd.h"
#include "asterisk/app.h"
#include "asterisk/dsp.h"
#include "asterisk/astdb.h"
#include "asterisk/manager.h"
#include "asterisk/causes.h"
#include "asterisk/term.h"
#include "asterisk/utils.h"
#include "asterisk/transcap.h"
#include "asterisk/stringfields.h"
#include "asterisk/abstract_jb.h"
#include "asterisk/smdi.h"
#include "asterisk/astobj.h"
#include "asterisk/event.h"
#include "asterisk/devicestate.h"

#define SMDI_MD_WAIT_TIMEOUT 1500 /* 1.5 seconds */

static const char *lbostr[] = {
"0 db (CSU)/0-133 feet (DSX-1)",
"133-266 feet (DSX-1)",
"266-399 feet (DSX-1)",
"399-533 feet (DSX-1)",
"533-655 feet (DSX-1)",
"-7.5db (CSU)",
"-15db (CSU)",
"-22.5db (CSU)"
};

/*! Global jitterbuffer configuration - by default, jb is disabled */
static struct ast_jb_conf default_jbconf =
{
   .flags = 0,
   .max_size = -1,
   .resync_threshold = -1,
   .impl = ""
};
static struct ast_jb_conf global_jbconf;

/* define this to send PRI user-user information elements */
#undef SUPPORT_USERUSER

/*! 
 * \note Define ZHONE_HACK to cause us to go off hook and then back on hook when
 * the user hangs up to reset the state machine so ring works properly.
 * This is used to be able to support kewlstart by putting the zhone in
 * groundstart mode since their forward disconnect supervision is entirely
 * broken even though their documentation says it isn't and their support
 * is entirely unwilling to provide any assistance with their channel banks
 * even though their web site says they support their products for life.
 */
/* #define ZHONE_HACK */

/*! \note
 * Define if you want to check the hook state for an FXO (FXS signalled) interface
 * before dialing on it.  Certain FXO interfaces always think they're out of
 * service with this method however.
 */
/* #define DAHDI_CHECK_HOOKSTATE */

/*! \brief Typically, how many rings before we should send Caller*ID */
#define DEFAULT_CIDRINGS 1

#define CHANNEL_PSEUDO -12

#define AST_LAW(p) (((p)->law == DAHDI_LAW_ALAW) ? AST_FORMAT_ALAW : AST_FORMAT_ULAW)


/*! \brief Signaling types that need to use MF detection should be placed in this macro */
#define NEED_MFDETECT(p) (((p)->sig == SIG_FEATDMF) || ((p)->sig == SIG_FEATDMF_TA) || ((p)->sig == SIG_E911) || ((p)->sig == SIG_FGC_CAMA) || ((p)->sig == SIG_FGC_CAMAMF) || ((p)->sig == SIG_FEATB)) 

static const char tdesc[] = "DAHDI Telephony Driver"
#ifdef HAVE_PRI
               " w/PRI"
#endif
#ifdef HAVE_SS7
          " w/SS7"
#endif
;

static const char config[] = "chan_dahdi.conf";

#define SIG_EM    DAHDI_SIG_EM
#define SIG_EMWINK   (0x0100000 | DAHDI_SIG_EM)
#define SIG_FEATD (0x0200000 | DAHDI_SIG_EM)
#define  SIG_FEATDMF (0x0400000 | DAHDI_SIG_EM)
#define  SIG_FEATB   (0x0800000 | DAHDI_SIG_EM)
#define  SIG_E911 (0x1000000 | DAHDI_SIG_EM)
#define  SIG_FEATDMF_TA (0x2000000 | DAHDI_SIG_EM)
#define  SIG_FGC_CAMA   (0x4000000 | DAHDI_SIG_EM)
#define  SIG_FGC_CAMAMF (0x8000000 | DAHDI_SIG_EM)
#define SIG_FXSLS DAHDI_SIG_FXSLS
#define SIG_FXSGS DAHDI_SIG_FXSGS
#define SIG_FXSKS DAHDI_SIG_FXSKS
#define SIG_FXOLS DAHDI_SIG_FXOLS
#define SIG_FXOGS DAHDI_SIG_FXOGS
#define SIG_FXOKS DAHDI_SIG_FXOKS
#define SIG_PRI      DAHDI_SIG_CLEAR
#define SIG_BRI      (0x2000000 | DAHDI_SIG_CLEAR)
#define SIG_BRI_PTMP (0X4000000 | DAHDI_SIG_CLEAR)
#define SIG_SS7      (0x1000000 | DAHDI_SIG_CLEAR)
#define  SIG_SF      DAHDI_SIG_SF
#define SIG_SFWINK   (0x0100000 | DAHDI_SIG_SF)
#define SIG_SF_FEATD (0x0200000 | DAHDI_SIG_SF)
#define  SIG_SF_FEATDMF (0x0400000 | DAHDI_SIG_SF)
#define  SIG_SF_FEATB   (0x0800000 | DAHDI_SIG_SF)
#define SIG_EM_E1 DAHDI_SIG_EM_E1
#define SIG_GR303FXOKS  (0x0100000 | DAHDI_SIG_FXOKS)
#define SIG_GR303FXSKS  (0x0100000 | DAHDI_SIG_FXSKS)

#ifdef LOTS_OF_SPANS
#define NUM_SPANS DAHDI_MAX_SPANS
#else
#define NUM_SPANS       32
#endif
#define NUM_DCHANS      4  /*!< No more than 4 d-channels */
#define MAX_CHANNELS 672      /*!< No more than a DS3 per trunk group */

#define CHAN_PSEUDO  -2

#define DCHAN_PROVISIONED (1 << 0)
#define DCHAN_NOTINALARM  (1 << 1)
#define DCHAN_UP          (1 << 2)

#define DCHAN_AVAILABLE (DCHAN_PROVISIONED | DCHAN_NOTINALARM | DCHAN_UP)

/* Overlap dialing option types */
#define DAHDI_OVERLAPDIAL_NONE 0
#define DAHDI_OVERLAPDIAL_OUTGOING 1
#define DAHDI_OVERLAPDIAL_INCOMING 2
#define DAHDI_OVERLAPDIAL_BOTH (DAHDI_OVERLAPDIAL_INCOMING|DAHDI_OVERLAPDIAL_OUTGOING)


#define CALLPROGRESS_PROGRESS    1
#define CALLPROGRESS_FAX_OUTGOING   2
#define CALLPROGRESS_FAX_INCOMING   4
#define CALLPROGRESS_FAX      (CALLPROGRESS_FAX_INCOMING | CALLPROGRESS_FAX_OUTGOING)

static char defaultcic[64] = "";
static char defaultozz[64] = "";

/*! Run this script when the MWI state changes on an FXO line, if mwimonitor is enabled */
static char mwimonitornotify[PATH_MAX] = "";

static char progzone[10] = "";

static int usedistinctiveringdetection = 0;
static int distinctiveringaftercid = 0;

static int numbufs = 4;

static int mwilevel = 512;

#ifdef HAVE_PRI
static struct ast_channel inuse;
#ifdef PRI_GETSET_TIMERS
static int pritimers[PRI_MAX_TIMERS];
#endif
static int pridebugfd = -1;
static char pridebugfilename[1024] = "";
#endif

/*! \brief Wait up to 16 seconds for first digit (FXO logic) */
static int firstdigittimeout = 16000;

/*! \brief How long to wait for following digits (FXO logic) */
static int gendigittimeout = 8000;

/*! \brief How long to wait for an extra digit, if there is an ambiguous match */
static int matchdigittimeout = 3000;

/*! \brief Protect the interface list (of dahdi_pvt's) */
AST_MUTEX_DEFINE_STATIC(iflock);


static int ifcount = 0;

#ifdef HAVE_PRI
AST_MUTEX_DEFINE_STATIC(pridebugfdlock);
#endif

/*! \brief Protect the monitoring thread, so only one process can kill or start it, and not
   when it's doing something critical. */
AST_MUTEX_DEFINE_STATIC(monlock);

/*! \brief This is the thread for the monitor which checks for input on the channels
   which are not currently in use. */
static pthread_t monitor_thread = AST_PTHREADT_NULL;
static ast_cond_t ss_thread_complete;
AST_MUTEX_DEFINE_STATIC(ss_thread_lock);
AST_MUTEX_DEFINE_STATIC(restart_lock);
static int ss_thread_count = 0;
static int num_restart_pending = 0;

static int restart_monitor(void);

static enum ast_bridge_result dahdi_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc, int timeoutms);

static int dahdi_sendtext(struct ast_channel *c, const char *text);

static void mwi_event_cb(const struct ast_event *event, void *userdata)
{
   /* This module does not handle MWI in an event-based manner.  However, it
    * subscribes to MWI for each mailbox that is configured so that the core
    * knows that we care about it.  Then, chan_dahdi will get the MWI from the
    * event cache instead of checking the mailbox directly. */
}

/*! \brief Avoid the silly dahdi_getevent which ignores a bunch of events */
static inline int dahdi_get_event(int fd)
{
   int j;
   if (ioctl(fd, DAHDI_GETEVENT, &j) == -1)
      return -1;
   return j;
}

/*! \brief Avoid the silly dahdi_waitevent which ignores a bunch of events */
static inline int dahdi_wait_event(int fd)
{
   int i, j = 0;
   i = DAHDI_IOMUX_SIGEVENT;
   if (ioctl(fd, DAHDI_IOMUX, &i) == -1)
      return -1;
   if (ioctl(fd, DAHDI_GETEVENT, &j) == -1)
      return -1;
   return j;
}

/*! Chunk size to read -- we use 20ms chunks to make things happy. */
#define READ_SIZE 160

#define MASK_AVAIL      (1 << 0) /*!< Channel available for PRI use */
#define MASK_INUSE      (1 << 1) /*!< Channel currently in use */

#define CALLWAITING_SILENT_SAMPLES  ( (300 * 8) / READ_SIZE) /*!< 300 ms */
#define CALLWAITING_REPEAT_SAMPLES  ( (10000 * 8) / READ_SIZE) /*!< 10,000 ms */
#define CIDCW_EXPIRE_SAMPLES     ( (500 * 8) / READ_SIZE) /*!< 500 ms */
#define MIN_MS_SINCE_FLASH       ( (2000) )  /*!< 2000 ms */
#define DEFAULT_RINGT            ( (8000 * 8) / READ_SIZE) /*!< 8,000 ms */

struct dahdi_pvt;

/*!
 * \brief Configured ring timeout base.
 * \note Value computed from "ringtimeout" read in from chan_dahdi.conf if it exists.
 */
static int ringt_base = DEFAULT_RINGT;

#ifdef HAVE_SS7

#define LINKSTATE_INALARM  (1 << 0)
#define LINKSTATE_STARTING (1 << 1)
#define LINKSTATE_UP    (1 << 2)
#define LINKSTATE_DOWN     (1 << 3)

#define SS7_NAI_DYNAMIC    -1

#define LINKSET_FLAG_EXPLICITACM (1 << 0)

struct dahdi_ss7 {
   pthread_t master;                /*!< Thread of master */
   ast_mutex_t lock;
   int fds[NUM_DCHANS];
   int numsigchans;
   int linkstate[NUM_DCHANS];
   int numchans;
   int type;
   enum {
      LINKSET_STATE_DOWN = 0,
      LINKSET_STATE_UP
   } state;
   char called_nai;                 /*!< Called Nature of Address Indicator */
   char calling_nai;                /*!< Calling Nature of Address Indicator */
   char internationalprefix[10];             /*!< country access code ('00' for european dialplans) */
   char nationalprefix[10];               /*!< area access code ('0' for european dialplans) */
   char subscriberprefix[20];             /*!< area access code + area code ('0'+area code for european dialplans) */
   char unknownprefix[20];                /*!< for unknown dialplans */
   struct ss7 *ss7;
   struct dahdi_pvt *pvts[MAX_CHANNELS];           /*!< Member channel pvt structs */
   int flags;                    /*!< Linkset flags */
};

static struct dahdi_ss7 linksets[NUM_SPANS];

static int cur_ss7type = -1;
static int cur_linkset = -1;
static int cur_pointcode = -1;
static int cur_cicbeginswith = -1;
static int cur_adjpointcode = -1;
static int cur_networkindicator = -1;
static int cur_defaultdpc = -1;
#endif /* HAVE_SS7 */

#ifdef HAVE_PRI

#define PVT_TO_CHANNEL(p) (((p)->prioffset) | ((p)->logicalspan << 8) | (p->pri->mastertrunkgroup ? 0x10000 : 0))
#define PRI_CHANNEL(p) ((p) & 0xff)
#define PRI_SPAN(p) (((p) >> 8) & 0xff)
#define PRI_EXPLICIT(p) (((p) >> 16) & 0x01)

struct dahdi_pri {
   pthread_t master;                /*!< Thread of master */
   ast_mutex_t lock;                /*!< Mutex */
   char idleext[AST_MAX_EXTENSION];          /*!< Where to idle extra calls */
   char idlecontext[AST_MAX_CONTEXT];           /*!< What context to use for idle */
   char idledial[AST_MAX_EXTENSION];            /*!< What to dial before dumping */
   int minunused;                   /*!< Min # of channels to keep empty */
   int minidle;                     /*!< Min # of "idling" calls to keep active */
   int nodetype;                    /*!< Node type */
   int switchtype;                     /*!< Type of switch to emulate */
   int nsf;                   /*!< Network-Specific Facilities */
   int dialplan;                    /*!< Dialing plan */
   int localdialplan;                  /*!< Local dialing plan */
   char internationalprefix[10];             /*!< country access code ('00' for european dialplans) */
   char nationalprefix[10];               /*!< area access code ('0' for european dialplans) */
   char localprefix[20];                  /*!< area access code + area code ('0'+area code for european dialplans) */
   char privateprefix[20];                /*!< for private dialplans */
   char unknownprefix[20];                /*!< for unknown dialplans */
   int dchannels[NUM_DCHANS];             /*!< What channel are the dchannels on */
   int trunkgroup;                     /*!< What our trunkgroup is */
   int mastertrunkgroup;                  /*!< What trunk group is our master */
   int prilogicalspan;                 /*!< Logical span number within trunk group */
   int numchans;                    /*!< Num of channels we represent */
   int overlapdial;                 /*!< In overlap dialing mode */
   int facilityenable;                 /*!< Enable facility IEs */
   struct pri *dchans[NUM_DCHANS];              /*!< Actual d-channels */
   int dchanavail[NUM_DCHANS];               /*!< Whether each channel is available */
   struct pri *pri;                 /*!< Currently active D-channel */
   /*! \brief TRUE if to dump PRI event info (Tested but never set) */
   int debug;
   int fds[NUM_DCHANS];                /*!< FD's for d-channels */
   /*! \brief Value set but not used */
   int offset;
   /*! \brief Span number put into user output messages */
   int span;
   /*! \brief TRUE if span is being reset/restarted */
   int resetting;
   /*! \brief Current position during a reset (-1 if not started) */
   int resetpos;
#ifdef HAVE_PRI_INBANDDISCONNECT
   unsigned int inbanddisconnect:1;          /*!< Should we support inband audio after receiving DISCONNECT? */
#endif
   time_t lastreset;                /*!< time when unused channels were last reset */
   long resetinterval;                 /*!< Interval (in seconds) for resetting unused channels */
   /*! \brief ISDN signalling type (SIG_PRI, SIG_BRI, SIG_BRI_PTMP, etc...) */
   int sig;
   struct dahdi_pvt *pvts[MAX_CHANNELS];           /*!< Member channel pvt structs */
   struct dahdi_pvt *crvs;                /*!< Member CRV structs */
   struct dahdi_pvt *crvend;                 /*!< Pointer to end of CRV structs */
};


static struct dahdi_pri pris[NUM_SPANS];

#if 0
#define DEFAULT_PRI_DEBUG (PRI_DEBUG_Q931_DUMP | PRI_DEBUG_Q921_DUMP | PRI_DEBUG_Q921_RAW | PRI_DEBUG_Q921_STATE)
#else
#define DEFAULT_PRI_DEBUG 0
#endif

static inline void pri_rel(struct dahdi_pri *pri)
{
   ast_mutex_unlock(&pri->lock);
}

#else
/*! Shut up the compiler */
struct dahdi_pri;
#endif

#define SUB_REAL  0        /*!< Active call */
#define SUB_CALLWAIT 1        /*!< Call-Waiting call on hold */
#define SUB_THREEWAY 2        /*!< Three-way call */

/* Polarity states */
#define POLARITY_IDLE   0
#define POLARITY_REV    1


struct distRingData {
   int ring[3];
   int range;
};
struct ringContextData {
   char contextData[AST_MAX_CONTEXT];
};
struct dahdi_distRings {
   struct distRingData ringnum[3];
   struct ringContextData ringContext[3];
};

static char *subnames[] = {
   "Real",
   "Callwait",
   "Threeway"
};

struct dahdi_subchannel {
   int dfd;
   struct ast_channel *owner;
   int chan;
   short buffer[AST_FRIENDLY_OFFSET/2 + READ_SIZE];
   struct ast_frame f;     /*!< One frame for each channel.  How did this ever work before? */
   unsigned int needringing:1;
   unsigned int needbusy:1;
   unsigned int needcongestion:1;
   unsigned int needcallerid:1;
   unsigned int needanswer:1;
   unsigned int needflash:1;
   unsigned int needhold:1;
   unsigned int needunhold:1;
   unsigned int linear:1;
   unsigned int inthreeway:1;
   struct dahdi_confinfo curconf;
};

#define CONF_USER_REAL     (1 << 0)
#define CONF_USER_THIRDCALL   (1 << 1)

#define MAX_SLAVES   4

static struct dahdi_pvt {
   ast_mutex_t lock;
   struct ast_channel *owner;       /*!< Our current active owner (if applicable) */
                     /*!< Up to three channels can be associated with this call */
      
   struct dahdi_subchannel sub_unused;    /*!< Just a safety precaution */
   struct dahdi_subchannel subs[3];       /*!< Sub-channels */
   struct dahdi_confinfo saveconf;        /*!< Saved conference info */

   struct dahdi_pvt *slaves[MAX_SLAVES];     /*!< Slave to us (follows our conferencing) */
   struct dahdi_pvt *master;           /*!< Master to us (we follow their conferencing) */
   int inconference;          /*!< If our real should be in the conference */
   
   int buf_no;             /*!< Number of buffers */
   int buf_policy;            /*!< Buffer policy */
   int sig;             /*!< Signalling style */
   /*!
    * \brief Nonzero if the signaling type is sent over a radio.
    * \note Set to a couple of nonzero values but it is only tested like a boolean.
    */
   int radio;
   int outsigmod;             /*!< Outbound Signalling style (modifier) */
   int oprmode;               /*!< "Operator Services" mode */
   struct dahdi_pvt *oprpeer;          /*!< "Operator Services" peer tech_pvt ptr */
   /*! \brief Amount of gain to increase during caller id */
   float cid_rxgain;
   /*! \brief Rx gain set by chan_dahdi.conf */
   float rxgain;
   /*! \brief Tx gain set by chan_dahdi.conf */
   float txgain;
   int tonezone;              /*!< tone zone for this chan, or -1 for default */
   struct dahdi_pvt *next;          /*!< Next channel in list */
   struct dahdi_pvt *prev;          /*!< Prev channel in list */

   /* flags */

   /*!
    * \brief TRUE if ADSI (Analog Display Services Interface) available
    * \note Set from the "adsi" value read in from chan_dahdi.conf
    */
   unsigned int adsi:1;
   /*!
    * \brief TRUE if we can use a polarity reversal to mark when an outgoing
    * call is answered by the remote party.
    * \note Set from the "answeronpolarityswitch" value read in from chan_dahdi.conf
    */
   unsigned int answeronpolarityswitch:1;
   /*!
    * \brief TRUE if busy detection is enabled.
    * (Listens for the beep-beep busy pattern.)
    * \note Set from the "busydetect" value read in from chan_dahdi.conf
    */
   unsigned int busydetect:1;
   /*!
    * \brief TRUE if call return is enabled.
    * (*69, if your dialplan doesn't catch this first)
    * \note Set from the "callreturn" value read in from chan_dahdi.conf
    */
   unsigned int callreturn:1;
   /*!
    * \brief TRUE if busy extensions will hear the call-waiting tone
    * and can use hook-flash to switch between callers.
    * \note Can be disabled by dialing *70.
    * \note Initialized with the "callwaiting" value read in from chan_dahdi.conf
    */
   unsigned int callwaiting:1;
   /*!
    * \brief TRUE if send caller ID for Call Waiting
    * \note Set from the "callwaitingcallerid" value read in from chan_dahdi.conf
    */
   unsigned int callwaitingcallerid:1;
   /*!
    * \brief TRUE if support for call forwarding enabled.
    * Dial *72 to enable call forwarding.
    * Dial *73 to disable call forwarding.
    * \note Set from the "cancallforward" value read in from chan_dahdi.conf
    */
   unsigned int cancallforward:1;
   /*!
    * \brief TRUE if support for call parking is enabled.
    * \note Set from the "canpark" value read in from chan_dahdi.conf
    */
   unsigned int canpark:1;
   /*! \brief TRUE if to wait for a DTMF digit to confirm answer */
   unsigned int confirmanswer:1;
   /*!
    * \brief TRUE if the channel is to be destroyed on hangup.
    * (Used by pseudo channels.)
    */
   unsigned int destroy:1;
   unsigned int didtdd:1;           /*!< flag to say its done it once */
   /*! \brief TRUE if analog type line dialed no digits in Dial() */
   unsigned int dialednone:1;
   /*! \brief TRUE if in the process of dialing digits or sending something. */
   unsigned int dialing:1;
   /*! \brief TRUE if the transfer capability of the call is digital. */
   unsigned int digital:1;
   /*! \brief TRUE if Do-Not-Disturb is enabled. */
   unsigned int dnd:1;
   /*! \brief XXX BOOLEAN Purpose??? */
   unsigned int echobreak:1;
   /*!
    * \brief TRUE if echo cancellation enabled when bridged.
    * \note Initialized with the "echocancelwhenbridged" value read in from chan_dahdi.conf
    * \note Disabled if the echo canceller is not setup.
    */
   unsigned int echocanbridged:1;
   /*! \brief TRUE if echo cancellation is turned on. */
   unsigned int echocanon:1;
   /*! \brief TRUE if a fax tone has already been handled. */
   unsigned int faxhandled:1;
   /*! \brief TRUE if over a radio and dahdi_read() has been called. */
   unsigned int firstradio:1;
   /*!
    * \brief TRUE if the call will be considered "hung up" on a polarity reversal.
    * \note Set from the "hanguponpolarityswitch" value read in from chan_dahdi.conf
    */
   unsigned int hanguponpolarityswitch:1;
   /*! \brief TRUE if DTMF detection needs to be done by hardware. */
   unsigned int hardwaredtmf:1;
   /*!
    * \brief TRUE if the outgoing caller ID is blocked/hidden.
    * \note Caller ID can be disabled by dialing *67.
    * \note Caller ID can be enabled by dialing *82.
    * \note Initialized with the "hidecallerid" value read in from chan_dahdi.conf
    */
   unsigned int hidecallerid:1;
   /*!
    * \brief TRUE if hide just the name not the number for legacy PBX use.
    * \note Only applies to PRI channels.
    * \note Set from the "hidecalleridname" value read in from chan_dahdi.conf
    */
   unsigned int hidecalleridname:1;
   /*! \brief TRUE if DTMF detection is disabled. */
   unsigned int ignoredtmf:1;
   /*!
    * \brief TRUE if the channel should be answered immediately
    * without attempting to gather any digits.
    * \note Set from the "immediate" value read in from chan_dahdi.conf
    */
   unsigned int immediate:1;
   /*! \brief TRUE if in an alarm condition. */
   unsigned int inalarm:1;
   /*! \brief TRUE if TDD in MATE mode */
   unsigned int mate:1;
   /*! \brief TRUE if we originated the call leg. */
   unsigned int outgoing:1;
   /* unsigned int overlapdial:1;         unused and potentially confusing */
   /*!
    * \brief TRUE if busy extensions will hear the call-waiting tone
    * and can use hook-flash to switch between callers.
    * \note Set from the "callwaiting" value read in from chan_dahdi.conf
    */
   unsigned int permcallwaiting:1;
   /*!
    * \brief TRUE if the outgoing caller ID is blocked/restricted/hidden.
    * \note Set from the "hidecallerid" value read in from chan_dahdi.conf
    */
   unsigned int permhidecallerid:1;
   /*!
    * \brief TRUE if PRI congestion/busy indications are sent out-of-band.
    * \note Set from the "priindication" value read in from chan_dahdi.conf
    */
   unsigned int priindication_oob:1;
   /*!
    * \brief TRUE if PRI B channels are always exclusively selected.
    * \note Set from the "priexclusive" value read in from chan_dahdi.conf
    */
   unsigned int priexclusive:1;
   /*!
    * \brief TRUE if we will pulse dial.
    * \note Set from the "pulsedial" value read in from chan_dahdi.conf
    */
   unsigned int pulse:1;
   /*! \brief TRUE if a pulsed digit was detected. (Pulse dial phone detected) */
   unsigned int pulsedial:1;
   unsigned int restartpending:1;      /*!< flag to ensure counted only once for restart */
   /*!
    * \brief TRUE if caller ID is restricted.
    * \note Set but not used.  Should be deleted.  Redundant with permhidecallerid.
    * \note Set from the "restrictcid" value read in from chan_dahdi.conf
    */
   unsigned int restrictcid:1;
   /*!
    * \brief TRUE if three way calling is enabled
    * \note Set from the "threewaycalling" value read in from chan_dahdi.conf
    */
   unsigned int threewaycalling:1;
   /*!
    * \brief TRUE if call transfer is enabled
    * \note For FXS ports (either direct analog or over T1/E1):
    *   Support flash-hook call transfer
    * \note For digital ports using ISDN PRI protocols:
    *   Support switch-side transfer (called 2BCT, RLT or other names)
    * \note Set from the "transfer" value read in from chan_dahdi.conf
    */
   unsigned int transfer:1;
   /*!
    * \brief TRUE if caller ID is used on this channel.
    * \note PRI and SS7 spans will save caller ID from the networking peer.
    * \note FXS ports will generate the caller ID spill.
    * \note FXO ports will listen for the caller ID spill.
    * \note Set from the "usecallerid" value read in from chan_dahdi.conf
    */
   unsigned int use_callerid:1;
   /*!
    * \brief TRUE if we will use the calling presentation setting
    * from the Asterisk channel for outgoing calls.
    * \note Only applies to PRI and SS7 channels.
    * \note Set from the "usecallingpres" value read in from chan_dahdi.conf
    */
   unsigned int use_callingpres:1;
   /*!
    * \brief TRUE if distinctive rings are to be detected.
    * \note For FXO lines
    * \note Set indirectly from the "usedistinctiveringdetection" value read in from chan_dahdi.conf
    */
   unsigned int usedistinctiveringdetection:1;
   /*!
    * \brief TRUE if we should use the callerid from incoming call on dahdi transfer.
    * \note Set from the "useincomingcalleridondahditransfer" value read in from chan_dahdi.conf
    */
   unsigned int dahditrcallerid:1;
   /*!
    * \brief TRUE if allowed to flash-transfer to busy channels.
    * \note Set from the "transfertobusy" value read in from chan_dahdi.conf
    */
   unsigned int transfertobusy:1;
   /*!
    * \brief TRUE if the FXO port monitors for neon type MWI indications from the other end.
    * \note Set if the "mwimonitor" value read in contains "neon" from chan_dahdi.conf
    */
   unsigned int mwimonitor_neon:1;
   /*!
    * \brief TRUE if the FXO port monitors for fsk type MWI indications from the other end.
    * \note Set if the "mwimonitor" value read in contains "fsk" from chan_dahdi.conf
    */
   unsigned int mwimonitor_fsk:1;
   /*! \brief TRUE if an MWI monitor thread is currently active */
   unsigned int mwimonitoractive:1;
   /*!
    * \brief TRUE if channel is out of reset and ready
    * \note Set but not used.
    */
   unsigned int inservice:1;
   /*!
    * \brief TRUE if the channel is locally blocked.
    * \note Applies to SS7 channels.
    */
   unsigned int locallyblocked:1;
   /*!
    * \brief TRUE if the channel is remotely blocked.
    * \note Applies to SS7 channels.
    */
   unsigned int remotelyblocked:1;
#if defined(HAVE_PRI) || defined(HAVE_SS7)
   /*!
    * \brief XXX BOOLEAN Purpose???
    * \note Applies to SS7 channels.
    */
   unsigned int rlt:1;
   /*! \brief TRUE if channel is alerting/ringing */
   unsigned int alerting:1;
   /*! \brief TRUE if the call has already gone/hungup */
   unsigned int alreadyhungup:1;
   /*!
    * \brief TRUE if this is an idle call
    * \note Applies to PRI channels.
    */
   unsigned int isidlecall:1;
   /*!
    * \brief TRUE if call is in a proceeding state.
    * The call has started working its way through the network.
    */
   unsigned int proceeding:1;
   /*! \brief TRUE if the call has seen progress through the network. */
   unsigned int progress:1;
   /*!
    * \brief TRUE if this channel is being reset/restarted
    * \note Applies to PRI channels.
    */
   unsigned int resetting:1;
   /*!
    * \brief TRUE if this channel has received a SETUP_ACKNOWLEDGE
    * \note Applies to PRI channels.
    */
   unsigned int setup_ack:1;
#endif
   /*!
    * \brief TRUE if SMDI (Simplified Message Desk Interface) is enabled
    * \note Set from the "usesmdi" value read in from chan_dahdi.conf
    */
   unsigned int use_smdi:1;
   /*! \brief The serial port to listen for SMDI data on */
   struct ast_smdi_interface *smdi_iface;

   /*! \brief Distinctive Ring data */
   struct dahdi_distRings drings;

   /*!
    * \brief The configured context for incoming calls.
    * \note The "context" string read in from chan_dahdi.conf
    */
   char context[AST_MAX_CONTEXT];
   /*!
    * \brief Saved context string.
    */
   char defcontext[AST_MAX_CONTEXT];
   /*! \brief Extension to use in the dialplan. */
   char exten[AST_MAX_EXTENSION];
   /*!
    * \brief Language configured for calls.
    * \note The "language" string read in from chan_dahdi.conf
    */
   char language[MAX_LANGUAGE];
   /*!
    * \brief The configured music-on-hold class to use for calls.
    * \note The "musicclass" or "mohinterpret" or "musiconhold" string read in from chan_dahdi.conf
    */
   char mohinterpret[MAX_MUSICCLASS];
   /*!
    * \brief Suggested music-on-hold class for peer channel to use for calls.
    * \note The "mohsuggest" string read in from chan_dahdi.conf
    */
   char mohsuggest[MAX_MUSICCLASS];
#if defined(PRI_ANI) || defined(HAVE_SS7)
   /*! \brief Automatic Number Identification number (Alternate PRI caller ID number) */
   char cid_ani[AST_MAX_EXTENSION];
#endif
   /*! \brief Automatic Number Identification code from PRI */
   int cid_ani2;
   /*! \brief Caller ID number from an incoming call. */
   char cid_num[AST_MAX_EXTENSION];
   /*! \brief Caller ID Q.931 TON/NPI field values.  Set by PRI. Zero otherwise. */
   int cid_ton;
   /*! \brief Caller ID name from an incoming call. */
   char cid_name[AST_MAX_EXTENSION];
   /*! \brief Last Caller ID number from an incoming call. */
   char lastcid_num[AST_MAX_EXTENSION];
   /*! \brief Last Caller ID name from an incoming call. */
   char lastcid_name[AST_MAX_EXTENSION];
   char *origcid_num;            /*!< malloced original callerid */
   char *origcid_name;           /*!< malloced original callerid */
   /*! \brief Call waiting number. */
   char callwait_num[AST_MAX_EXTENSION];
   /*! \brief Call waiting name. */
   char callwait_name[AST_MAX_EXTENSION];
   /*! \brief Redirecting Directory Number Information Service (RDNIS) number */
   char rdnis[AST_MAX_EXTENSION];
   /*! \brief Dialed Number Identifier */
   char dnid[AST_MAX_EXTENSION];
   /*!
    * \brief Bitmapped groups this belongs to.
    * \note The "group" bitmapped group string read in from chan_dahdi.conf
    */
   ast_group_t group;
   /*! \brief Active PCM encoding format: DAHDI_LAW_ALAW or DAHDI_LAW_MULAW */
   int law;
   int confno;             /*!< Our conference */
   int confusers;             /*!< Who is using our conference */
   int propconfno;               /*!< Propagated conference number */
   /*!
    * \brief Bitmapped call groups this belongs to.
    * \note The "callgroup" bitmapped group string read in from chan_dahdi.conf
    */
   ast_group_t callgroup;
   /*!
    * \brief Bitmapped pickup groups this belongs to.
    * \note The "pickupgroup" bitmapped group string read in from chan_dahdi.conf
    */
   ast_group_t pickupgroup;
   /*!
    * \brief Channel variable list with associated values to set when a channel is created.
    * \note The "setvar" strings read in from chan_dahdi.conf
    */
   struct ast_variable *vars;
   int channel;               /*!< Channel Number or CRV */
   int span;               /*!< Span number */
   time_t guardtime;          /*!< Must wait this much time before using for new call */
   int cid_signalling;           /*!< CID signalling type bell202 or v23 */
   int cid_start;             /*!< CID start indicator, polarity or ring */
   int callingpres;           /*!< The value of callling presentation that we're going to use when placing a PRI call */
   int callwaitingrepeat;           /*!< How many samples to wait before repeating call waiting */
   int cidcwexpire;           /*!< When to expire our muting for CID/CW */
   /*! \brief Analog caller ID waveform sample buffer */
   unsigned char *cidspill;
   /*! \brief Position in the cidspill buffer to send out next. */
   int cidpos;
   /*! \brief Length of the cidspill buffer containing samples. */
   int cidlen;
   /*! \brief Ring timeout timer?? */
   int ringt;
   /*!
    * \brief Ring timeout base.
    * \note Value computed indirectly from "ringtimeout" read in from chan_dahdi.conf
    */
   int ringt_base;
   /*!
    * \brief Number of most significant digits/characters to strip from the dialed number.
    * \note Feature is deprecated.  Use dialplan logic.
    * \note The characters are stripped before the PRI TON/NPI prefix
    * characters are processed.
    */
   int stripmsd;
   /*! \brief BOOLEAN. XXX Meaning what?? */
   int callwaitcas;
   /*! \brief Number of call waiting rings. */
   int callwaitrings;
   /*! \brief Echo cancel parameters. */
   struct {
      struct dahdi_echocanparams head;
      struct dahdi_echocanparam params[DAHDI_MAX_ECHOCANPARAMS];
   } echocancel;
   /*!
    * \brief Echo training time. 0 = disabled
    * \note Set from the "echotraining" value read in from chan_dahdi.conf
    */
   int echotraining;
   /*! \brief Filled with 'w'.  XXX Purpose?? */
   char echorest[20];
   /*!
    * \brief Number of times to see "busy" tone before hanging up.
    * \note Set from the "busycount" value read in from chan_dahdi.conf
    */
   int busycount;
   /*!
    * \brief Length of "busy" tone on time.
    * \note Set from the "busypattern" value read in from chan_dahdi.conf
    */
   int busy_tonelength;
   /*!
    * \brief Length of "busy" tone off time.
    * \note Set from the "busypattern" value read in from chan_dahdi.conf
    */
   int busy_quietlength;
   /*!
    * \brief Bitmapped call progress detection flags. CALLPROGRESS_xxx values.
    * \note Bits set from the "callprogress" and "faxdetect" values read in from chan_dahdi.conf
    */
   int callprogress;
   struct timeval flashtime;        /*!< Last flash-hook time */
   /*! \brief Opaque DSP configuration structure. */
   struct ast_dsp *dsp;
   //int cref;             /*!< Call reference number (Not used) */
   /*! \brief DAHDI dial operation command struct for ioctl() call. */
   struct dahdi_dialoperation dop;
   int whichwink;             /*!< SIG_FEATDMF_TA Which wink are we on? */
   /*! \brief Second part of SIG_FEATDMF_TA wink operation. */
   char finaldial[64];
   char accountcode[AST_MAX_ACCOUNT_CODE];      /*!< Account code */
   int amaflags;              /*!< AMA Flags */
   struct tdd_state *tdd;           /*!< TDD flag */
   /*! \brief Accumulated call forwarding number. */
   char call_forward[AST_MAX_EXTENSION];
   /*!
    * \brief Voice mailbox location.
    * \note Set from the "mailbox" string read in from chan_dahdi.conf
    */
   char mailbox[AST_MAX_EXTENSION];
   /*! \brief Opaque event subscription parameters for message waiting indication support. */
   struct ast_event_sub *mwi_event_sub;
   /*! \brief Delayed dialing for E911.  Overlap digits for ISDN. */
   char dialdest[256];
   /*! \brief Time the interface went on-hook. */
   int onhooktime;
   /*! \brief -1 = unknown, 0 = no messages, 1 = new messages available */
   int msgstate;
   int distinctivering;          /*!< Which distinctivering to use */
   int cidrings;              /*!< Which ring to deliver CID on */
   int dtmfrelax;             /*!< whether to run in relaxed DTMF mode */
   /*! \brief Holding place for event injected from outside normal operation. */
   int fake_event;
   /*!
    * \brief Minimal time period (ms) between the answer polarity
    * switch and hangup polarity switch.
    */
   int polarityonanswerdelay;
   /*! \brief Start delay time if polarityonanswerdelay is nonzero. */
   struct timeval polaritydelaytv;
   /*!
    * \brief Send caller ID after this many rings.
    * \note Set from the "sendcalleridafter" value read in from chan_dahdi.conf
    */
   int sendcalleridafter;
#ifdef HAVE_PRI
   /*! \brief DAHDI PRI control parameters */
   struct dahdi_pri *pri;
   /*! \brief XXX Purpose??? */
   struct dahdi_pvt *bearer;
   /*! \brief XXX Purpose??? */
   struct dahdi_pvt *realcall;
   /*! \brief Opaque libpri call control structure */
   q931_call *call;
   /*! \brief Channel number in span. */
   int prioffset;
   /*! \brief Logical span number within trunk group */
   int logicalspan;
#endif   
   /*! \brief Current line interface polarity. POLARITY_IDLE, POLARITY_REV */
   int polarity;
   /*! \brief DSP feature flags: DSP_FEATURE_xxx */
   int dsp_features;
#ifdef HAVE_SS7
   /*! \brief SS7 control parameters */
   struct dahdi_ss7 *ss7;
   /*! \brief Opaque libss7 call control structure */
   struct isup_call *ss7call;
   char charge_number[50];
   char gen_add_number[50];
   char gen_dig_number[50];
   char orig_called_num[50];
   char redirecting_num[50];
   char generic_name[50];
   unsigned char gen_add_num_plan;
   unsigned char gen_add_nai;
   unsigned char gen_add_pres_ind;
   unsigned char gen_add_type;
   unsigned char gen_dig_type;
   unsigned char gen_dig_scheme;
   char jip_number[50];
   unsigned char lspi_type;
   unsigned char lspi_scheme;
   unsigned char lspi_context;
   char lspi_ident[50];
   unsigned int call_ref_ident;
   unsigned int call_ref_pc;
   unsigned char calling_party_cat;
   int transcap;
   int cic;                   /*!< CIC associated with channel */
   unsigned int dpc;                /*!< CIC's DPC */
   unsigned int loopedback:1;
#endif
   /*! \brief DTMF digit in progress.  0 when no digit in progress. */
   char begindigit;
} *iflist = NULL, *ifend = NULL;

/*! \brief Channel configuration from chan_dahdi.conf .
 * This struct is used for parsing the [channels] section of chan_dahdi.conf.
 * Generally there is a field here for every possible configuration item.
 *
 * The state of fields is saved along the parsing and whenever a 'channel'
 * statement is reached, the current dahdi_chan_conf is used to configure the 
 * channel (struct dahdi_pvt)
 *
 * \see dahdi_chan_init for the default values.
 */
struct dahdi_chan_conf {
   struct dahdi_pvt chan;
#ifdef HAVE_PRI
   struct dahdi_pri pri;
#endif

#ifdef HAVE_SS7
   struct dahdi_ss7 ss7;
#endif
   struct dahdi_params timing;
   int is_sig_auto; /*!< Use channel signalling from DAHDI? */

   /*!
    * \brief The serial port to listen for SMDI data on
    * \note Set from the "smdiport" string read in from chan_dahdi.conf
    */
   char smdi_port[SMDI_MAX_FILENAME_LEN];
};

/*! returns a new dahdi_chan_conf with default values (by-value) */
static struct dahdi_chan_conf dahdi_chan_conf_default(void) {
   /* recall that if a field is not included here it is initialized
    * to 0 or equivalent
    */
   struct dahdi_chan_conf conf = {
#ifdef HAVE_PRI
      .pri = {
         .nsf = PRI_NSF_NONE,
         .switchtype = PRI_SWITCH_NI2,
         .dialplan = PRI_NATIONAL_ISDN + 1,
         .localdialplan = PRI_NATIONAL_ISDN + 1,
         .nodetype = PRI_CPE,

         .minunused = 2,
         .idleext = "",
         .idledial = "",
         .internationalprefix = "",
         .nationalprefix = "",
         .localprefix = "",
         .privateprefix = "",
         .unknownprefix = "",
         .resetinterval = -1,
      },
#endif
#ifdef HAVE_SS7
      .ss7 = {
         .called_nai = SS7_NAI_NATIONAL,
         .calling_nai = SS7_NAI_NATIONAL,
         .internationalprefix = "",
         .nationalprefix = "",
         .subscriberprefix = "",
         .unknownprefix = ""
      },
#endif
      .chan = {
         .context = "default",
         .cid_num = "",
         .cid_name = "",
         .mohinterpret = "default",
         .mohsuggest = "",
         .transfertobusy = 1,

         .cid_signalling = CID_SIG_BELL,
         .cid_start = CID_START_RING,
         .dahditrcallerid = 0,
         .use_callerid = 1,
         .sig = -1,
         .outsigmod = -1,

         .cid_rxgain = +5.0,

         .tonezone = -1,

         .echocancel.head.tap_length = 1,

         .busycount = 3,

         .accountcode = "",

         .mailbox = "",


         .polarityonanswerdelay = 600,

         .sendcalleridafter = DEFAULT_CIDRINGS,
      
         .buf_policy = DAHDI_POLICY_IMMEDIATE,
         .buf_no = numbufs
      },
      .timing = {
         .prewinktime = -1,
         .preflashtime = -1,
         .winktime = -1,
         .flashtime = -1,
         .starttime = -1,
         .rxwinktime = -1,
         .rxflashtime = -1,
         .debouncetime = -1
      },
      .is_sig_auto = 1,
      .smdi_port = "/dev/ttyS0",
   };

   return conf;
}


static struct ast_channel *dahdi_request(const char *type, int format, void *data, int *cause);
static int dahdi_digit_begin(struct ast_channel *ast, char digit);
static int dahdi_digit_end(struct ast_channel *ast, char digit, unsigned int duration);
static int dahdi_sendtext(struct ast_channel *c, const char *text);
static int dahdi_call(struct ast_channel *ast, char *rdest, int timeout);
static int dahdi_hangup(struct ast_channel *ast);
static int dahdi_answer(struct ast_channel *ast);
static struct ast_frame *dahdi_read(struct ast_channel *ast);
static int dahdi_write(struct ast_channel *ast, struct ast_frame *frame);
static struct ast_frame *dahdi_exception(struct ast_channel *ast);
static int dahdi_indicate(struct ast_channel *chan, int condition, const void *data, size_t datalen);
static int dahdi_fixup(struct ast_channel *oldchan, struct ast_channel *newchan);
static int dahdi_setoption(struct ast_channel *chan, int option, void *data, int datalen);
static int dahdi_func_read(struct ast_channel *chan, const char *function, char *data, char *buf, size_t len);

static const struct ast_channel_tech dahdi_tech = {
   .type = "DAHDI",
   .description = tdesc,
   .capabilities = AST_FORMAT_SLINEAR | AST_FORMAT_ULAW | AST_FORMAT_ALAW,
   .requester = dahdi_request,
   .send_digit_begin = dahdi_digit_begin,
   .send_digit_end = dahdi_digit_end,
   .send_text = dahdi_sendtext,
   .call = dahdi_call,
   .hangup = dahdi_hangup,
   .answer = dahdi_answer,
   .read = dahdi_read,
   .write = dahdi_write,
   .bridge = dahdi_bridge,
   .exception = dahdi_exception,
   .indicate = dahdi_indicate,
   .fixup = dahdi_fixup,
   .setoption = dahdi_setoption,
   .func_channel_read = dahdi_func_read,
};

#ifdef HAVE_PRI
#define GET_CHANNEL(p) ((p)->bearer ? (p)->bearer->channel : p->channel)
#else
#define GET_CHANNEL(p) ((p)->channel)
#endif

struct dahdi_pvt *round_robin[32];

#ifdef HAVE_PRI
static inline int pri_grab(struct dahdi_pvt *pvt, struct dahdi_pri *pri)
{
   int res;
   /* Grab the lock first */
   do {
      res = ast_mutex_trylock(&pri->lock);
      if (res) {
         DEADLOCK_AVOIDANCE(&pvt->lock);
      }
   } while (res);
   /* Then break the poll */
   if (pri->master != AST_PTHREADT_NULL)
      pthread_kill(pri->master, SIGURG);
   return 0;
}
#endif

#ifdef HAVE_SS7
static inline void ss7_rel(struct dahdi_ss7 *ss7)
{
   ast_mutex_unlock(&ss7->lock);
}

static inline int ss7_grab(struct dahdi_pvt *pvt, struct dahdi_ss7 *pri)
{
   int res;
   /* Grab the lock first */
   do {
      res = ast_mutex_trylock(&pri->lock);
      if (res) {
         ast_mutex_unlock(&pvt->lock);
         /* Release the lock and try again */
         usleep(1);
         ast_mutex_lock(&pvt->lock);
      }
   } while (res);
   /* Then break the poll */
   if (pri->master != AST_PTHREADT_NULL)
      pthread_kill(pri->master, SIGURG);
   return 0;
}
#endif
#define NUM_CADENCE_MAX 25
static int num_cadence = 4;
static int user_has_defined_cadences = 0;

static struct dahdi_ring_cadence cadences[NUM_CADENCE_MAX] = {
   { { 125, 125, 2000, 4000 } },       /*!< Quick chirp followed by normal ring */
   { { 250, 250, 500, 1000, 250, 250, 500, 4000 } }, /*!< British style ring */
   { { 125, 125, 125, 125, 125, 4000 } }, /*!< Three short bursts */
   { { 1000, 500, 2500, 5000 } },   /*!< Long ring */
};

/*! \brief cidrings says in which pause to transmit the cid information, where the first pause
 * is 1, the second pause is 2 and so on.
 */

static int cidrings[NUM_CADENCE_MAX] = {
   2,                            /*!< Right after first long ring */
   4,                            /*!< Right after long part */
   3,                            /*!< After third chirp */
   2,                            /*!< Second spell */
};

#define ISTRUNK(p) ((p->sig == SIG_FXSLS) || (p->sig == SIG_FXSKS) || \
         (p->sig == SIG_FXSGS) || (p->sig == SIG_PRI))

#define CANBUSYDETECT(p) (ISTRUNK(p) || (p->sig & (SIG_EM | SIG_EM_E1 | SIG_SF)) /* || (p->sig & __DAHDI_SIG_FXO) */)
#define CANPROGRESSDETECT(p) (ISTRUNK(p) || (p->sig & (SIG_EM | SIG_EM_E1 | SIG_SF)) /* || (p->sig & __DAHDI_SIG_FXO) */)

static int dahdi_get_index(struct ast_channel *ast, struct dahdi_pvt *p, int nullok)
{
   int res;
   if (p->subs[SUB_REAL].owner == ast)
      res = 0;
   else if (p->subs[SUB_CALLWAIT].owner == ast)
      res = 1;
   else if (p->subs[SUB_THREEWAY].owner == ast)
      res = 2;
   else {
      res = -1;
      if (!nullok)
         ast_log(LOG_WARNING, "Unable to get index, and nullok is not asserted\n");
   }
   return res;
}

#ifdef HAVE_PRI
static void wakeup_sub(struct dahdi_pvt *p, int a, struct dahdi_pri *pri)
#else
static void wakeup_sub(struct dahdi_pvt *p, int a, void *pri)
#endif
{
#ifdef HAVE_PRI
   if (pri)
      ast_mutex_unlock(&pri->lock);
#endif         
   for (;;) {
      if (p->subs[a].owner) {
         if (ast_channel_trylock(p->subs[a].owner)) {
            DEADLOCK_AVOIDANCE(&p->lock);
         } else {
            ast_queue_frame(p->subs[a].owner, &ast_null_frame);
            ast_channel_unlock(p->subs[a].owner);
            break;
         }
      } else
         break;
   }
#ifdef HAVE_PRI
   if (pri)
      ast_mutex_lock(&pri->lock);
#endif         
}

static void dahdi_queue_frame(struct dahdi_pvt *p, struct ast_frame *f, void *data)
{
#ifdef HAVE_PRI
   struct dahdi_pri *pri = (struct dahdi_pri*) data;
#endif
#ifdef HAVE_SS7
   struct dahdi_ss7 *ss7 = (struct dahdi_ss7*) data;
#endif
   /* We must unlock the PRI to avoid the possibility of a deadlock */
#if defined(HAVE_PRI) || defined(HAVE_SS7)
   if (data) {
      switch (p->sig) {
#ifdef HAVE_PRI
      case SIG_BRI:
      case SIG_BRI_PTMP:
      case SIG_PRI:
         ast_mutex_unlock(&pri->lock);
         break;
#endif
#ifdef HAVE_SS7
      case SIG_SS7:
         ast_mutex_unlock(&ss7->lock);
         break;
#endif
      default:
         break;
      }
   }
#endif      
   for (;;) {
      if (p->owner) {
         if (ast_channel_trylock(p->owner)) {
            DEADLOCK_AVOIDANCE(&p->lock);
         } else {
            ast_queue_frame(p->owner, f);
            ast_channel_unlock(p->owner);
            break;
         }
      } else
         break;
   }
#if defined(HAVE_PRI) || defined(HAVE_SS7)
   if (data) {
      switch (p->sig) {
#ifdef HAVE_PRI
      case SIG_BRI:
      case SIG_BRI_PTMP:
      case SIG_PRI:
         ast_mutex_lock(&pri->lock);
         break;
#endif
#ifdef HAVE_SS7
      case SIG_SS7:
         ast_mutex_lock(&ss7->lock);
         break;
#endif
      default:
         break;
      }
   }

#endif      
}

static int restore_gains(struct dahdi_pvt *p);

static void swap_subs(struct dahdi_pvt *p, int a, int b)
{
   int tchan;
   int tinthreeway;
   struct ast_channel *towner;

   ast_debug(1, "Swapping %d and %d\n", a, b);

   tchan = p->subs[a].chan;
   towner = p->subs[a].owner;
   tinthreeway = p->subs[a].inthreeway;

   p->subs[a].chan = p->subs[b].chan;
   p->subs[a].owner = p->subs[b].owner;
   p->subs[a].inthreeway = p->subs[b].inthreeway;

   p->subs[b].chan = tchan;
   p->subs[b].owner = towner;
   p->subs[b].inthreeway = tinthreeway;

   if (p->subs[a].owner) 
      ast_channel_set_fd(p->subs[a].owner, 0, p->subs[a].dfd);
   if (p->subs[b].owner) 
      ast_channel_set_fd(p->subs[b].owner, 0, p->subs[b].dfd);
   wakeup_sub(p, a, NULL);
   wakeup_sub(p, b, NULL);
}

static int dahdi_open(char *fn)
{
   int fd;
   int isnum;
   int chan = 0;
   int bs;
   int x;
   isnum = 1;
   for (x = 0; x < strlen(fn); x++) {
      if (!isdigit(fn[x])) {
         isnum = 0;
         break;
      }
   }
   if (isnum) {
      chan = atoi(fn);
      if (chan < 1) {
         ast_log(LOG_WARNING, "Invalid channel number '%s'\n", fn);
         return -1;
      }
      fn = "/dev/dahdi/channel";
   }
   fd = open(fn, O_RDWR | O_NONBLOCK);
   if (fd < 0) {
      ast_log(LOG_WARNING, "Unable to open '%s': %s\n", fn, strerror(errno));
      return -1;
   }
   if (chan) {
      if (ioctl(fd, DAHDI_SPECIFY, &chan)) {
         x = errno;
         close(fd);
         errno = x;
         ast_log(LOG_WARNING, "Unable to specify channel %d: %s\n", chan, strerror(errno));
         return -1;
      }
   }
   bs = READ_SIZE;
   if (ioctl(fd, DAHDI_SET_BLOCKSIZE, &bs) == -1) {
      ast_log(LOG_WARNING, "Unable to set blocksize '%d': %s\n", bs,  strerror(errno));
      x = errno;
      close(fd);
      errno = x;
      return -1;
   }
   return fd;
}

static void dahdi_close(int fd)
{
   if (fd > 0)
      close(fd);
}

static void dahdi_close_sub(struct dahdi_pvt *chan_pvt, int sub_num)
{
   dahdi_close(chan_pvt->subs[sub_num].dfd);
   chan_pvt->subs[sub_num].dfd = -1;
}

#ifdef HAVE_PRI
static void dahdi_close_pri_fd(struct dahdi_pri *pri, int fd_num)
{
   dahdi_close(pri->fds[fd_num]);
   pri->fds[fd_num] = -1;
}
#endif

#ifdef HAVE_SS7
static void dahdi_close_ss7_fd(struct dahdi_ss7 *ss7, int fd_num)
{
   dahdi_close(ss7->fds[fd_num]);
   ss7->fds[fd_num] = -1;
}
#endif

static int dahdi_setlinear(int dfd, int linear)
{
   int res;
   res = ioctl(dfd, DAHDI_SETLINEAR, &linear);
   if (res)
      return res;
   return 0;
}


static int alloc_sub(struct dahdi_pvt *p, int x)
{
   struct dahdi_bufferinfo bi;
   int res;
   if (p->subs[x].dfd >= 0) {
      ast_log(LOG_WARNING, "%s subchannel of %d already in use\n", subnames[x], p->channel);
      return -1;
   }

   p->subs[x].dfd = dahdi_open("/dev/dahdi/pseudo");
   if (p->subs[x].dfd <= -1) {
      ast_log(LOG_WARNING, "Unable to open pseudo channel: %s\n", strerror(errno));
      return -1;
   }

   res = ioctl(p->subs[x].dfd, DAHDI_GET_BUFINFO, &bi);
   if (!res) {
      bi.txbufpolicy = p->buf_policy;
      bi.rxbufpolicy = p->buf_policy;
      bi.numbufs = p->buf_no;
      res = ioctl(p->subs[x].dfd, DAHDI_SET_BUFINFO, &bi);
      if (res < 0) {
         ast_log(LOG_WARNING, "Unable to set buffer policy on channel %d: %s\n", x, strerror(errno));
      }
   } else 
      ast_log(LOG_WARNING, "Unable to check buffer policy on channel %d: %s\n", x, strerror(errno));

   if (ioctl(p->subs[x].dfd, DAHDI_CHANNO, &p->subs[x].chan) == 1) {
      ast_log(LOG_WARNING, "Unable to get channel number for pseudo channel on FD %d: %s\n", p->subs[x].dfd, strerror(errno));
      dahdi_close_sub(p, x);
      p->subs[x].dfd = -1;
      return -1;
   }
   ast_debug(1, "Allocated %s subchannel on FD %d channel %d\n", subnames[x], p->subs[x].dfd, p->subs[x].chan);
   return 0;
}

static int unalloc_sub(struct dahdi_pvt *p, int x)
{
   if (!x) {
      ast_log(LOG_WARNING, "Trying to unalloc the real channel %d?!?\n", p->channel);
      return -1;
   }
   ast_debug(1, "Released sub %d of channel %d\n", x, p->channel);
   dahdi_close_sub(p, x);
   p->subs[x].linear = 0;
   p->subs[x].chan = 0;
   p->subs[x].owner = NULL;
   p->subs[x].inthreeway = 0;
   p->polarity = POLARITY_IDLE;
   memset(&p->subs[x].curconf, 0, sizeof(p->subs[x].curconf));
   return 0;
}

static int digit_to_dtmfindex(char digit)
{
   if (isdigit(digit))
      return DAHDI_TONE_DTMF_BASE + (digit - '0');
   else if (digit >= 'A' && digit <= 'D')
      return DAHDI_TONE_DTMF_A + (digit - 'A');
   else if (digit >= 'a' && digit <= 'd')
      return DAHDI_TONE_DTMF_A + (digit - 'a');
   else if (digit == '*')
      return DAHDI_TONE_DTMF_s;
   else if (digit == '#')
      return DAHDI_TONE_DTMF_p;
   else
      return -1;
}

static int dahdi_digit_begin(struct ast_channel *chan, char digit)
{
   struct dahdi_pvt *pvt;
   int index;
   int dtmf = -1;
   
   pvt = chan->tech_pvt;

   ast_mutex_lock(&pvt->lock);

   index = dahdi_get_index(chan, pvt, 0);

   if ((index != SUB_REAL) || !pvt->owner)
      goto out;

#ifdef HAVE_PRI
   if (((pvt->sig == SIG_PRI) || (pvt->sig == SIG_BRI) || (pvt->sig == SIG_BRI_PTMP)) 
         && (chan->_state == AST_STATE_DIALING) && !pvt->proceeding) {
      if (pvt->setup_ack) {
         if (!pri_grab(pvt, pvt->pri)) {
            pri_information(pvt->pri->pri, pvt->call, digit);
            pri_rel(pvt->pri);
         } else
            ast_log(LOG_WARNING, "Unable to grab PRI on span %d\n", pvt->span);
      } else if (strlen(pvt->dialdest) < sizeof(pvt->dialdest) - 1) {
         int res;
         ast_debug(1, "Queueing digit '%c' since setup_ack not yet received\n", digit);
         res = strlen(pvt->dialdest);
         pvt->dialdest[res++] = digit;
         pvt->dialdest[res] = '\0';
      }
      goto out;
   }
#endif
   if ((dtmf = digit_to_dtmfindex(digit)) == -1)
      goto out;

   if (pvt->pulse || ioctl(pvt->subs[SUB_REAL].dfd, DAHDI_SENDTONE, &dtmf)) {
      int res;
      struct dahdi_dialoperation zo = {
         .op = DAHDI_DIAL_OP_APPEND,
      };

      zo.dialstr[0] = 'T';
      zo.dialstr[1] = digit;
      zo.dialstr[2] = '\0';
      if ((res = ioctl(pvt->subs[SUB_REAL].dfd, DAHDI_DIAL, &zo)))
         ast_log(LOG_WARNING, "Couldn't dial digit %c: %s\n", digit, strerror(errno));
      else
         pvt->dialing = 1;
   } else {
      ast_debug(1, "Started VLDTMF digit '%c'\n", digit);
      pvt->dialing = 1;
      pvt->begindigit = digit;
   }

out:
   ast_mutex_unlock(&pvt->lock);

   return 0;
}

static int dahdi_digit_end(struct ast_channel *chan, char digit, unsigned int duration)
{
   struct dahdi_pvt *pvt;
   int res = 0;
   int index;
   int x;
   
   pvt = chan->tech_pvt;

   ast_mutex_lock(&pvt->lock);
   
   index = dahdi_get_index(chan, pvt, 0);

   if ((index != SUB_REAL) || !pvt->owner || pvt->pulse)
      goto out;

#ifdef HAVE_PRI
   /* This means that the digit was already sent via PRI signalling */
   if (((pvt->sig == SIG_PRI) || (pvt->sig == SIG_BRI) || (pvt->sig == SIG_BRI_PTMP))
         && !pvt->begindigit)
      goto out;
#endif

   if (pvt->begindigit) {
      x = -1;
      ast_debug(1, "Ending VLDTMF digit '%c'\n", digit);
      res = ioctl(pvt->subs[SUB_REAL].dfd, DAHDI_SENDTONE, &x);
      pvt->dialing = 0;
      pvt->begindigit = 0;
   }

out:
   ast_mutex_unlock(&pvt->lock);

   return res;
}

static char *events[] = {
   "No event",
   "On hook",
   "Ring/Answered",
   "Wink/Flash",
   "Alarm",
   "No more alarm",
   "HDLC Abort",
   "HDLC Overrun",
   "HDLC Bad FCS",
   "Dial Complete",
   "Ringer On",
   "Ringer Off",
   "Hook Transition Complete",
   "Bits Changed",
   "Pulse Start",
   "Timer Expired",
   "Timer Ping",
   "Polarity Reversal",
   "Ring Begin",
};

static struct {
   int alarm;
   char *name;
} alarms[] = {
   { DAHDI_ALARM_RED, "Red Alarm" },
   { DAHDI_ALARM_YELLOW, "Yellow Alarm" },
   { DAHDI_ALARM_BLUE, "Blue Alarm" },
   { DAHDI_ALARM_RECOVER, "Recovering" },
   { DAHDI_ALARM_LOOPBACK, "Loopback" },
   { DAHDI_ALARM_NOTOPEN, "Not Open" },
   { DAHDI_ALARM_NONE, "None" },
};

static char *alarm2str(int alarm)
{
   int x;
   for (x = 0; x < ARRAY_LEN(alarms); x++) {
      if (alarms[x].alarm & alarm)
         return alarms[x].name;
   }
   return alarm ? "Unknown Alarm" : "No Alarm";
}

static char *event2str(int event)
{
   static char buf[256];
   if ((event < (ARRAY_LEN(events))) && (event > -1))
      return events[event];
   sprintf(buf, "Event %d", event); /* safe */
   return buf;
}

#ifdef HAVE_PRI
static char *dialplan2str(int dialplan)
{
   if (dialplan == -1 || dialplan == -2) {
      return("Dynamically set dialplan in ISDN");
   }
   return (pri_plan2str(dialplan));
}
#endif

static char *dahdi_sig2str(int sig)
{
   static char buf[256];
   switch (sig) {
   case SIG_EM:
      return "E & M Immediate";
   case SIG_EMWINK:
      return "E & M Wink";
   case SIG_EM_E1:
      return "E & M E1";
   case SIG_FEATD:
      return "Feature Group D (DTMF)";
   case SIG_FEATDMF:
      return "Feature Group D (MF)";
   case SIG_FEATDMF_TA:
      return "Feature Groud D (MF) Tandem Access";
   case SIG_FEATB:
      return "Feature Group B (MF)";
   case SIG_E911:
      return "E911 (MF)";
   case SIG_FGC_CAMA:
      return "FGC/CAMA (Dialpulse)";
   case SIG_FGC_CAMAMF:
      return "FGC/CAMA (MF)";
   case SIG_FXSLS:
      return "FXS Loopstart";
   case SIG_FXSGS:
      return "FXS Groundstart";
   case SIG_FXSKS:
      return "FXS Kewlstart";
   case SIG_FXOLS:
      return "FXO Loopstart";
   case SIG_FXOGS:
      return "FXO Groundstart";
   case SIG_FXOKS:
      return "FXO Kewlstart";
   case SIG_PRI:
      return "ISDN PRI";
   case SIG_BRI:
      return "ISDN BRI Point to Point";
   case SIG_BRI_PTMP:
      return "ISDN BRI Point to MultiPoint";
   case SIG_SS7:
      return "SS7";
   case SIG_SF:
      return "SF (Tone) Immediate";
   case SIG_SFWINK:
      return "SF (Tone) Wink";
   case SIG_SF_FEATD:
      return "SF (Tone) with Feature Group D (DTMF)";
   case SIG_SF_FEATDMF:
      return "SF (Tone) with Feature Group D (MF)";
   case SIG_SF_FEATB:
      return "SF (Tone) with Feature Group B (MF)";
   case SIG_GR303FXOKS:
      return "GR-303 with FXOKS";
   case SIG_GR303FXSKS:
      return "GR-303 with FXSKS";
   case 0:
      return "Pseudo";
   default:
      snprintf(buf, sizeof(buf), "Unknown signalling %d", sig);
      return buf;
   }
}

#define sig2str dahdi_sig2str

static int conf_add(struct dahdi_pvt *p, struct dahdi_subchannel *c, int index, int slavechannel)
{
   /* If the conference already exists, and we're already in it
      don't bother doing anything */
   struct dahdi_confinfo zi;
   
   memset(&zi, 0, sizeof(zi));
   zi.chan = 0;

   if (slavechannel > 0) {
      /* If we have only one slave, do a digital mon */
      zi.confmode = DAHDI_CONF_DIGITALMON;
      zi.confno = slavechannel;
   } else {
      if (!index) {
         /* Real-side and pseudo-side both participate in conference */
         zi.confmode = DAHDI_CONF_REALANDPSEUDO | DAHDI_CONF_TALKER | DAHDI_CONF_LISTENER |
            DAHDI_CONF_PSEUDO_TALKER | DAHDI_CONF_PSEUDO_LISTENER;
      } else
         zi.confmode = DAHDI_CONF_CONF | DAHDI_CONF_TALKER | DAHDI_CONF_LISTENER;
      zi.confno = p->confno;
   }
   if ((zi.confno == c->curconf.confno) && (zi.confmode == c->curconf.confmode))
      return 0;
   if (c->dfd < 0)
      return 0;
   if (ioctl(c->dfd, DAHDI_SETCONF, &zi)) {
      ast_log(LOG_WARNING, "Failed to add %d to conference %d/%d: %s\n", c->dfd, zi.confmode, zi.confno, strerror(errno));
      return -1;
   }
   if (slavechannel < 1) {
      p->confno = zi.confno;
   }
   memcpy(&c->curconf, &zi, sizeof(c->curconf));
   ast_debug(1, "Added %d to conference %d/%d\n", c->dfd, c->curconf.confmode, c->curconf.confno);
   return 0;
}

static int isourconf(struct dahdi_pvt *p, struct dahdi_subchannel *c)
{
   /* If they're listening to our channel, they're ours */  
   if ((p->channel == c->curconf.confno) && (c->curconf.confmode == DAHDI_CONF_DIGITALMON))
      return 1;
   /* If they're a talker on our (allocated) conference, they're ours */
   if ((p->confno > 0) && (p->confno == c->curconf.confno) && (c->curconf.confmode & DAHDI_CONF_TALKER))
      return 1;
   return 0;
}

static int conf_del(struct dahdi_pvt *p, struct dahdi_subchannel *c, int index)
{
   struct dahdi_confinfo zi;
   if (/* Can't delete if there's no dfd */
      (c->dfd < 0) ||
      /* Don't delete from the conference if it's not our conference */
      !isourconf(p, c)
      /* Don't delete if we don't think it's conferenced at all (implied) */
      ) return 0;
   memset(&zi, 0, sizeof(zi));
   if (ioctl(c->dfd, DAHDI_SETCONF, &zi)) {
      ast_log(LOG_WARNING, "Failed to drop %d from conference %d/%d: %s\n", c->dfd, c->curconf.confmode, c->curconf.confno, strerror(errno));
      return -1;
   }
   ast_debug(1, "Removed %d from conference %d/%d\n", c->dfd, c->curconf.confmode, c->curconf.confno);
   memcpy(&c->curconf, &zi, sizeof(c->curconf));
   return 0;
}

static int isslavenative(struct dahdi_pvt *p, struct dahdi_pvt **out)
{
   int x;
   int useslavenative;
   struct dahdi_pvt *slave = NULL;
   /* Start out optimistic */
   useslavenative = 1;
   /* Update conference state in a stateless fashion */
   for (x = 0; x < 3; x++) {
      /* Any three-way calling makes slave native mode *definitely* out
         of the question */
      if ((p->subs[x].dfd > -1) && p->subs[x].inthreeway)
         useslavenative = 0;
   }
   /* If we don't have any 3-way calls, check to see if we have
      precisely one slave */
   if (useslavenative) {
      for (x = 0; x < MAX_SLAVES; x++) {
         if (p->slaves[x]) {
            if (slave) {
               /* Whoops already have a slave!  No 
                  slave native and stop right away */
               slave = NULL;
               useslavenative = 0;
               break;
            } else {
               /* We have one slave so far */
               slave = p->slaves[x];
            }
         }
      }
   }
   /* If no slave, slave native definitely out */
   if (!slave)
      useslavenative = 0;
   else if (slave->law != p->law) {
      useslavenative = 0;
      slave = NULL;
   }
   if (out)
      *out = slave;
   return useslavenative;
}

static int reset_conf(struct dahdi_pvt *p)
{
   p->confno = -1;
   memset(&p->subs[SUB_REAL].curconf, 0, sizeof(p->subs[SUB_REAL].curconf));
   if (p->subs[SUB_REAL].dfd > -1) {
      struct dahdi_confinfo zi;

      memset(&zi, 0, sizeof(zi));
      if (ioctl(p->subs[SUB_REAL].dfd, DAHDI_SETCONF, &zi))
         ast_log(LOG_WARNING, "Failed to reset conferencing on channel %d: %s\n", p->channel, strerror(errno));
   }
   return 0;
}

static int update_conf(struct dahdi_pvt *p)
{
   int needconf = 0;
   int x;
   int useslavenative;
   struct dahdi_pvt *slave = NULL;

   useslavenative = isslavenative(p, &slave);
   /* Start with the obvious, general stuff */
   for (x = 0; x < 3; x++) {
      /* Look for three way calls */
      if ((p->subs[x].dfd > -1) && p->subs[x].inthreeway) {
         conf_add(p, &p->subs[x], x, 0);
         needconf++;
      } else {
         conf_del(p, &p->subs[x], x);
      }
   }
   /* If we have a slave, add him to our conference now. or DAX
      if this is slave native */
   for (x = 0; x < MAX_SLAVES; x++) {
      if (p->slaves[x]) {
         if (useslavenative)
            conf_add(p, &p->slaves[x]->subs[SUB_REAL], SUB_REAL, GET_CHANNEL(p));
         else {
            conf_add(p, &p->slaves[x]->subs[SUB_REAL], SUB_REAL, 0);
            needconf++;
         }
      }
   }
   /* If we're supposed to be in there, do so now */
   if (p->inconference && !p->subs[SUB_REAL].inthreeway) {
      if (useslavenative)
         conf_add(p, &p->subs[SUB_REAL], SUB_REAL, GET_CHANNEL(slave));
      else {
         conf_add(p, &p->subs[SUB_REAL], SUB_REAL, 0);
         needconf++;
      }
   }
   /* If we have a master, add ourselves to his conference */
   if (p->master) {
      if (isslavenative(p->master, NULL)) {
         conf_add(p->master, &p->subs[SUB_REAL], SUB_REAL, GET_CHANNEL(p->master));
      } else {
         conf_add(p->master, &p->subs[SUB_REAL], SUB_REAL, 0);
      }
   }
   if (!needconf) {
      /* Nobody is left (or should be left) in our conference.
         Kill it. */
      p->confno = -1;
   }
   ast_debug(1, "Updated conferencing on %d, with %d conference users\n", p->channel, needconf);
   return 0;
}

static void dahdi_enable_ec(struct dahdi_pvt *p)
{
   int x;
   int res;
   if (!p)
      return;
   if (p->echocanon) {
      ast_debug(1, "Echo cancellation already on\n");
      return;
   }
   if (p->digital) {
      ast_debug(1, "Echo cancellation isn't required on digital connection\n");
      return;
   }
   if (p->echocancel.head.tap_length) {
      if ((p->sig == SIG_BRI) || (p->sig == SIG_BRI_PTMP) || (p->sig == SIG_PRI) || (p->sig == SIG_SS7)) {
         x = 1;
         res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_AUDIOMODE, &x);
         if (res)
            ast_log(LOG_WARNING, "Unable to enable audio mode on channel %d (%s)\n", p->channel, strerror(errno));
      }
      res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_ECHOCANCEL_PARAMS, &p->echocancel);
      if (res)  {
         ast_log(LOG_WARNING, "Unable to enable echo cancellation on channel %d (%s)\n", p->channel, strerror(errno));
      } else {
         p->echocanon = 1;
         ast_debug(1, "Enabled echo cancellation on channel %d\n", p->channel);
      }
   } else
      ast_debug(1, "No echo cancellation requested\n");
}

static void dahdi_train_ec(struct dahdi_pvt *p)
{
   int x;
   int res;
   
   if (p && p->echocanon && p->echotraining) {
      x = p->echotraining;
      res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_ECHOTRAIN, &x);
      if (res)
         ast_log(LOG_WARNING, "Unable to request echo training on channel %d: %s\n", p->channel, strerror(errno));
      else
         ast_debug(1, "Engaged echo training on channel %d\n", p->channel);
   } else {
      ast_debug(1, "No echo training requested\n");
   }
}

static void dahdi_disable_ec(struct dahdi_pvt *p)
{
   int res;

   if (p->echocanon) {
      struct dahdi_echocanparams ecp = { .tap_length = 0 };

      res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_ECHOCANCEL_PARAMS, &ecp);

      if (res)
         ast_log(LOG_WARNING, "Unable to disable echo cancellation on channel %d: %s\n", p->channel, strerror(errno));
      else
         ast_debug(1, "Disabled echo cancellation on channel %d\n", p->channel);
   }

   p->echocanon = 0;
}

static void fill_txgain(struct dahdi_gains *g, float gain, int law)
{
   int j;
   int k;
   float linear_gain = pow(10.0, gain / 20.0);

   switch (law) {
   case DAHDI_LAW_ALAW:
      for (j = 0; j < ARRAY_LEN(g->txgain); j++) {
         if (gain) {
            k = (int) (((float) AST_ALAW(j)) * linear_gain);
            if (k > 32767) k = 32767;
            if (k < -32767) k = -32767;
            g->txgain[j] = AST_LIN2A(k);
         } else {
            g->txgain[j] = j;
         }
      }
      break;
   case DAHDI_LAW_MULAW:
      for (j = 0; j < ARRAY_LEN(g->txgain); j++) {
         if (gain) {
            k = (int) (((float) AST_MULAW(j)) * linear_gain);
            if (k > 32767) k = 32767;
            if (k < -32767) k = -32767;
            g->txgain[j] = AST_LIN2MU(k);
         } else {
            g->txgain[j] = j;
         }
      }
      break;
   }
}

static void fill_rxgain(struct dahdi_gains *g, float gain, int law)
{
   int j;
   int k;
   float linear_gain = pow(10.0, gain / 20.0);

   switch (law) {
   case DAHDI_LAW_ALAW:
      for (j = 0; j < ARRAY_LEN(g->rxgain); j++) {
         if (gain) {
            k = (int) (((float) AST_ALAW(j)) * linear_gain);
            if (k > 32767) k = 32767;
            if (k < -32767) k = -32767;
            g->rxgain[j] = AST_LIN2A(k);
         } else {
            g->rxgain[j] = j;
         }
      }
      break;
   case DAHDI_LAW_MULAW:
      for (j = 0; j < ARRAY_LEN(g->rxgain); j++) {
         if (gain) {
            k = (int) (((float) AST_MULAW(j)) * linear_gain);
            if (k > 32767) k = 32767;
            if (k < -32767) k = -32767;
            g->rxgain[j] = AST_LIN2MU(k);
         } else {
            g->rxgain[j] = j;
         }
      }
      break;
   }
}

static int set_actual_txgain(int fd, int chan, float gain, int law)
{
   struct dahdi_gains g;
   int res;

   memset(&g, 0, sizeof(g));
   g.chan = chan;
   res = ioctl(fd, DAHDI_GETGAINS, &g);
   if (res) {
      ast_debug(1, "Failed to read gains: %s\n", strerror(errno));
      return res;
   }

   fill_txgain(&g, gain, law);

   return ioctl(fd, DAHDI_SETGAINS, &g);
}

static int set_actual_rxgain(int fd, int chan, float gain, int law)
{
   struct dahdi_gains g;
   int res;

   memset(&g, 0, sizeof(g));
   g.chan = chan;
   res = ioctl(fd, DAHDI_GETGAINS, &g);
   if (res) {
      ast_debug(1, "Failed to read gains: %s\n", strerror(errno));
      return res;
   }

   fill_rxgain(&g, gain, law);

   return ioctl(fd, DAHDI_SETGAINS, &g);
}

static int set_actual_gain(int fd, int chan, float rxgain, float txgain, int law)
{
   return set_actual_txgain(fd, chan, txgain, law) | set_actual_rxgain(fd, chan, rxgain, law);
}

static int bump_gains(struct dahdi_pvt *p)
{
   int res;

   /* Bump receive gain by value stored in cid_rxgain */
   res = set_actual_gain(p->subs[SUB_REAL].dfd, 0, p->rxgain + p->cid_rxgain, p->txgain, p->law);
   if (res) {
      ast_log(LOG_WARNING, "Unable to bump gain: %s\n", strerror(errno));
      return -1;
   }

   return 0;
}

static int restore_gains(struct dahdi_pvt *p)
{
   int res;

   res = set_actual_gain(p->subs[SUB_REAL].dfd, 0, p->rxgain, p->txgain, p->law);
   if (res) {
      ast_log(LOG_WARNING, "Unable to restore gains: %s\n", strerror(errno));
      return -1;
   }

   return 0;
}

static inline int dahdi_set_hook(int fd, int hs)
{
   int x, res;

   x = hs;
   res = ioctl(fd, DAHDI_HOOK, &x);

   if (res < 0) {
      if (errno == EINPROGRESS)
         return 0;
      ast_log(LOG_WARNING, "DAHDI hook failed returned %d (trying %d): %s\n", res, hs, strerror(errno));
      /* will expectedly fail if phone is off hook during operation, such as during a restart */
   }

   return res;
}

static inline int dahdi_confmute(struct dahdi_pvt *p, int muted)
{
   int x, y, res;
   x = muted;
   if ((p->sig == SIG_PRI) || (p->sig == SIG_SS7) || (p->sig == SIG_BRI) || (p->sig == SIG_BRI_PTMP)) {
      y = 1;
      res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_AUDIOMODE, &y);
      if (res)
         ast_log(LOG_WARNING, "Unable to set audio mode on %d: %s\n", p->channel, strerror(errno));
   }
   res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_CONFMUTE, &x);
   if (res < 0)
      ast_log(LOG_WARNING, "DAHDI confmute(%d) failed on channel %d: %s\n", muted, p->channel, strerror(errno));
   return res;
}

static int save_conference(struct dahdi_pvt *p)
{
   struct dahdi_confinfo c;
   int res;
   if (p->saveconf.confmode) {
      ast_log(LOG_WARNING, "Can't save conference -- already in use\n");
      return -1;
   }
   p->saveconf.chan = 0;
   res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_GETCONF, &p->saveconf);
   if (res) {
      ast_log(LOG_WARNING, "Unable to get conference info: %s\n", strerror(errno));
      p->saveconf.confmode = 0;
      return -1;
   }
   memset(&c, 0, sizeof(c));
   c.confmode = DAHDI_CONF_NORMAL;
   res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_SETCONF, &c);
   if (res) {
      ast_log(LOG_WARNING, "Unable to set conference info: %s\n", strerror(errno));
      return -1;
   }
   ast_debug(1, "Disabled conferencing\n");
   return 0;
}

/*!
 * \brief Send MWI state change
 *
 * \arg mailbox_full This is the mailbox associated with the FXO line that the
 *      MWI state has changed on.
 * \arg thereornot This argument should simply be set to 1 or 0, to indicate
 *      whether there are messages waiting or not.
 *
 *  \return nothing
 *
 * This function does two things:
 *
 * 1) It generates an internal Asterisk event notifying any other module that
 *    cares about MWI that the state of a mailbox has changed.
 *
 * 2) It runs the script specified by the mwimonitornotify option to allow
 *    some custom handling of the state change.
 */
static void notify_message(char *mailbox_full, int thereornot)
{
   char s[sizeof(mwimonitornotify) + 80];
   struct ast_event *event;
   char *mailbox, *context;

   /* Strip off @default */
   context = mailbox = ast_strdupa(mailbox_full);
   strsep(&context, "@");
   if (ast_strlen_zero(context))
      context = "default";

   if (!(event = ast_event_new(AST_EVENT_MWI,
         AST_EVENT_IE_MAILBOX, AST_EVENT_IE_PLTYPE_STR, mailbox,
         AST_EVENT_IE_CONTEXT, AST_EVENT_IE_PLTYPE_STR, context,
         AST_EVENT_IE_NEWMSGS, AST_EVENT_IE_PLTYPE_UINT, thereornot,
         AST_EVENT_IE_OLDMSGS, AST_EVENT_IE_PLTYPE_UINT, thereornot,
         AST_EVENT_IE_END))) {
      return;
   }

   ast_event_queue_and_cache(event,
      AST_EVENT_IE_MAILBOX, AST_EVENT_IE_PLTYPE_STR,
      AST_EVENT_IE_CONTEXT, AST_EVENT_IE_PLTYPE_STR,
      AST_EVENT_IE_END);

   if (!ast_strlen_zero(mailbox) && !ast_strlen_zero(mwimonitornotify)) {
      snprintf(s, sizeof(s), "%s %s %d", mwimonitornotify, mailbox, thereornot);
      ast_safe_system(s);
   }
}

static int restore_conference(struct dahdi_pvt *p)
{
   int res;
   if (p->saveconf.confmode) {
      res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_SETCONF, &p->saveconf);
      p->saveconf.confmode = 0;
      if (res) {
         ast_log(LOG_WARNING, "Unable to restore conference info: %s\n", strerror(errno));
         return -1;
      }
   }
   ast_debug(1, "Restored conferencing\n");
   return 0;
}

static int send_callerid(struct dahdi_pvt *p);

static int send_cwcidspill(struct dahdi_pvt *p)
{
   p->callwaitcas = 0;
   p->cidcwexpire = 0;
   if (!(p->cidspill = ast_malloc(MAX_CALLERID_SIZE)))
      return -1;
   p->cidlen = ast_callerid_callwaiting_generate(p->cidspill, p->callwait_name, p->callwait_num, AST_LAW(p));
   /* Make sure we account for the end */
   p->cidlen += READ_SIZE * 4;
   p->cidpos = 0;
   send_callerid(p);
   ast_verb(3, "CPE supports Call Waiting Caller*ID.  Sending '%s/%s'\n", p->callwait_name, p->callwait_num);
   return 0;
}

static int has_voicemail(struct dahdi_pvt *p)
{
   int new_msgs;
   struct ast_event *event;
   char *mailbox, *context;

   mailbox = context = ast_strdupa(p->mailbox);
   strsep(&context, "@");
   if (ast_strlen_zero(context))
      context = "default";

   event = ast_event_get_cached(AST_EVENT_MWI,
      AST_EVENT_IE_MAILBOX, AST_EVENT_IE_PLTYPE_STR, mailbox,
      AST_EVENT_IE_CONTEXT, AST_EVENT_IE_PLTYPE_STR, context,
      AST_EVENT_IE_NEWMSGS, AST_EVENT_IE_PLTYPE_EXISTS,
      AST_EVENT_IE_END);

   if (event) {
      new_msgs = ast_event_get_ie_uint(event, AST_EVENT_IE_NEWMSGS);
      ast_event_destroy(event);
   } else
      new_msgs = ast_app_has_voicemail(p->mailbox, NULL);

   return new_msgs;
}

static int send_callerid(struct dahdi_pvt *p)
{
   /* Assumes spill in p->cidspill, p->cidlen in length and we're p->cidpos into it */
   int res;
   /* Take out of linear mode if necessary */
   if (p->subs[SUB_REAL].linear) {
      p->subs[SUB_REAL].linear = 0;
      dahdi_setlinear(p->subs[SUB_REAL].dfd, 0);
   }
   while (p->cidpos < p->cidlen) {
      res = write(p->subs[SUB_REAL].dfd, p->cidspill + p->cidpos, p->cidlen - p->cidpos);
      if (res < 0) {
         if (errno == EAGAIN)
            return 0;
         else {
            ast_log(LOG_WARNING, "write failed: %s\n", strerror(errno));
            return -1;
         }
      }
      if (!res)
         return 0;
      p->cidpos += res;
   }
   ast_free(p->cidspill);
   p->cidspill = NULL;
   if (p->callwaitcas) {
      /* Wait for CID/CW to expire */
      p->cidcwexpire = CIDCW_EXPIRE_SAMPLES;
   } else
      restore_conference(p);
   return 0;
}

static int dahdi_callwait(struct ast_channel *ast)
{
   struct dahdi_pvt *p = ast->tech_pvt;
   p->callwaitingrepeat = CALLWAITING_REPEAT_SAMPLES;
   if (p->cidspill) {
      ast_log(LOG_WARNING, "Spill already exists?!?\n");
      ast_free(p->cidspill);
   }
   if (!(p->cidspill = ast_malloc(2400 /* SAS */ + 680 /* CAS */ + READ_SIZE * 4)))
      return -1;
   save_conference(p);
   /* Silence */
   memset(p->cidspill, 0x7f, 2400 + 600 + READ_SIZE * 4);
   if (!p->callwaitrings && p->callwaitingcallerid) {
      ast_gen_cas(p->cidspill, 1, 2400 + 680, AST_LAW(p));
      p->callwaitcas = 1;
      p->cidlen = 2400 + 680 + READ_SIZE * 4;
   } else {
      ast_gen_cas(p->cidspill, 1, 2400, AST_LAW(p));
      p->callwaitcas = 0;
      p->cidlen = 2400 + READ_SIZE * 4;
   }
   p->cidpos = 0;
   send_callerid(p);
   
   return 0;
}

#ifdef HAVE_SS7
static unsigned char cid_pres2ss7pres(int cid_pres)
{
    return (cid_pres >> 5) & 0x03;
}

static unsigned char cid_pres2ss7screen(int cid_pres)
{
   return cid_pres & 0x03;
}
#endif

static int dahdi_call(struct ast_channel *ast, char *rdest, int timeout)
{
   struct dahdi_pvt *p = ast->tech_pvt;
   int x, res, index,mysig;
   char *c, *n, *l;
#ifdef HAVE_PRI
   char *s = NULL;
#endif
   char dest[256]; /* must be same length as p->dialdest */
   ast_mutex_lock(&p->lock);
   ast_copy_string(dest, rdest, sizeof(dest));
   ast_copy_string(p->dialdest, rdest, sizeof(p->dialdest));
   if ((ast->_state == AST_STATE_BUSY)) {
      p->subs[SUB_REAL].needbusy = 1;
      ast_mutex_unlock(&p->lock);
      return 0;
   }
   if ((ast->_state != AST_STATE_DOWN) && (ast->_state != AST_STATE_RESERVED)) {
      ast_log(LOG_WARNING, "dahdi_call called on %s, neither down nor reserved\n", ast->name);
      ast_mutex_unlock(&p->lock);
      return -1;
   }
   p->dialednone = 0;
   if ((p->radio || (p->oprmode < 0)))  /* if a radio channel, up immediately */
   {
      /* Special pseudo -- automatically up */
      ast_setstate(ast, AST_STATE_UP); 
      ast_mutex_unlock(&p->lock);
      return 0;
   }
   x = DAHDI_FLUSH_READ | DAHDI_FLUSH_WRITE;
   res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_FLUSH, &x);
   if (res)
      ast_log(LOG_WARNING, "Unable to flush input on channel %d: %s\n", p->channel, strerror(errno));
   p->outgoing = 1;

   set_actual_gain(p->subs[SUB_REAL].dfd, 0, p->rxgain, p->txgain, p->law);

   mysig = p->sig;
   if (p->outsigmod > -1)
      mysig = p->outsigmod;

   switch (mysig) {
   case SIG_FXOLS:
   case SIG_FXOGS:
   case SIG_FXOKS:
      if (p->owner == ast) {
         /* Normal ring, on hook */
         
         /* Don't send audio while on hook, until the call is answered */
         p->dialing = 1;
         if (p->use_callerid) {
            /* Generate the Caller-ID spill if desired */
            if (p->cidspill) {
               ast_log(LOG_WARNING, "cidspill already exists??\n");
               ast_free(p->cidspill);
            }
            p->callwaitcas = 0;
            if ((p->cidspill = ast_malloc(MAX_CALLERID_SIZE))) {
               p->cidlen = ast_callerid_generate(p->cidspill, ast->cid.cid_name, ast->cid.cid_num, AST_LAW(p));
               p->cidpos = 0;
               send_callerid(p);
            }
         }
         /* Choose proper cadence */
         if ((p->distinctivering > 0) && (p->distinctivering <= num_cadence)) {
            if (ioctl(p->subs[SUB_REAL].dfd, DAHDI_SETCADENCE, &cadences[p->distinctivering - 1]))
               ast_log(LOG_WARNING, "Unable to set distinctive ring cadence %d on '%s': %s\n", p->distinctivering, ast->name, strerror(errno));
            p->cidrings = cidrings[p->distinctivering - 1];
         } else {
            if (ioctl(p->subs[SUB_REAL].dfd, DAHDI_SETCADENCE, NULL))
               ast_log(LOG_WARNING, "Unable to reset default ring on '%s': %s\n", ast->name, strerror(errno));
            p->cidrings = p->sendcalleridafter;
         }

         /* nick@dccinc.com 4/3/03 mods to allow for deferred dialing */
         c = strchr(dest, '/');
         if (c)
            c++;
         if (c && (strlen(c) < p->stripmsd)) {
            ast_log(LOG_WARNING, "Number '%s' is shorter than stripmsd (%d)\n", c, p->stripmsd);
            c = NULL;
         }
         if (c) {
            p->dop.op = DAHDI_DIAL_OP_REPLACE;
            snprintf(p->dop.dialstr, sizeof(p->dop.dialstr), "Tw%s", c);
            ast_debug(1, "FXO: setup deferred dialstring: %s\n", c);
         } else {
            p->dop.dialstr[0] = '\0';
         }
         x = DAHDI_RING;
         if (ioctl(p->subs[SUB_REAL].dfd, DAHDI_HOOK, &x) && (errno != EINPROGRESS)) {
            ast_log(LOG_WARNING, "Unable to ring phone: %s\n", strerror(errno));
            ast_mutex_unlock(&p->lock);
            return -1;
         }
         p->dialing = 1;
      } else {
         /* Call waiting call */
         p->callwaitrings = 0;
         if (ast->cid.cid_num)
            ast_copy_string(p->callwait_num, ast->cid.cid_num, sizeof(p->callwait_num));
         else
            p->callwait_num[0] = '\0';
         if (ast->cid.cid_name)
            ast_copy_string(p->callwait_name, ast->cid.cid_name, sizeof(p->callwait_name));
         else
            p->callwait_name[0] = '\0';
         /* Call waiting tone instead */
         if (dahdi_callwait(ast)) {
            ast_mutex_unlock(&p->lock);
            return -1;
         }
         /* Make ring-back */
         if (tone_zone_play_tone(p->subs[SUB_CALLWAIT].dfd, DAHDI_TONE_RINGTONE))
            ast_log(LOG_WARNING, "Unable to generate call-wait ring-back on channel %s\n", ast->name);
            
      }
      n = ast->cid.cid_name;
      l = ast->cid.cid_num;
      if (l)
         ast_copy_string(p->lastcid_num, l, sizeof(p->lastcid_num));
      else
         p->lastcid_num[0] = '\0';
      if (n)
         ast_copy_string(p->lastcid_name, n, sizeof(p->lastcid_name));
      else
         p->lastcid_name[0] = '\0';
      ast_setstate(ast, AST_STATE_RINGING);
      index = dahdi_get_index(ast, p, 0);
      if (index > -1) {
         p->subs[index].needringing = 1;
      }
      break;
   case SIG_FXSLS:
   case SIG_FXSGS:
   case SIG_FXSKS:
      if (p->answeronpolarityswitch || p->hanguponpolarityswitch) {
         ast_debug(1, "Ignore possible polarity reversal on line seizure\n");
         p->polaritydelaytv = ast_tvnow();
      }
      /* fall through */
   case SIG_EMWINK:
   case SIG_EM:
   case SIG_EM_E1:
   case SIG_FEATD:
   case SIG_FEATDMF:
   case SIG_E911:
   case SIG_FGC_CAMA:
   case SIG_FGC_CAMAMF:
   case SIG_FEATB:
   case SIG_SFWINK:
   case SIG_SF:
   case SIG_SF_FEATD:
   case SIG_SF_FEATDMF:
   case SIG_FEATDMF_TA:
   case SIG_SF_FEATB:
      c = strchr(dest, '/');
      if (c)
         c++;
      else
         c = "";
      if (strlen(c) < p->stripmsd) {
         ast_log(LOG_WARNING, "Number '%s' is shorter than stripmsd (%d)\n", c, p->stripmsd);
         ast_mutex_unlock(&p->lock);
         return -1;
      }
#ifdef HAVE_PRI
      /* Start the trunk, if not GR-303 */
      if (!p->pri) {
#endif
         x = DAHDI_START;
         res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_HOOK, &x);
         if (res < 0) {
            if (errno != EINPROGRESS) {
               ast_log(LOG_WARNING, "Unable to start channel: %s\n", strerror(errno));
               ast_mutex_unlock(&p->lock);
               return -1;
            }
         }
#ifdef HAVE_PRI
      }
#endif
      ast_debug(1, "Dialing '%s'\n", c);
      p->dop.op = DAHDI_DIAL_OP_REPLACE;

      c += p->stripmsd;

      switch (mysig) {
      case SIG_FEATD:
         l = ast->cid.cid_num;
         if (l) 
            snprintf(p->dop.dialstr, sizeof(p->dop.dialstr), "T*%s*%s*", l, c);
         else
            snprintf(p->dop.dialstr, sizeof(p->dop.dialstr), "T**%s*", c);
         break;
      case SIG_FEATDMF:
         l = ast->cid.cid_num;
         if (l) 
            snprintf(p->dop.dialstr, sizeof(p->dop.dialstr), "M*00%s#*%s#", l, c);
         else
            snprintf(p->dop.dialstr, sizeof(p->dop.dialstr), "M*02#*%s#", c);
         break;
      case SIG_FEATDMF_TA:
      {
         const char *cic, *ozz;

         /* If you have to go through a Tandem Access point you need to use this */
         ozz = pbx_builtin_getvar_helper(p->owner, "FEATDMF_OZZ");
         if (!ozz)
            ozz = defaultozz;
         cic = pbx_builtin_getvar_helper(p->owner, "FEATDMF_CIC");
         if (!cic)
            cic = defaultcic;
         if (!ozz || !cic) {
            ast_log(LOG_WARNING, "Unable to dial channel of type feature group D MF tandem access without CIC or OZZ set\n");
            ast_mutex_unlock(&p->lock);
            return -1;
         }
         snprintf(p->dop.dialstr, sizeof(p->dop.dialstr), "M*%s%s#", ozz, cic);
         snprintf(p->finaldial, sizeof(p->finaldial), "M*%s#", c);
         p->whichwink = 0;
      }
         break;
      case SIG_E911:
         ast_copy_string(p->dop.dialstr, "M*911#", sizeof(p->dop.dialstr));
         break;
      case SIG_FGC_CAMA:
         snprintf(p->dop.dialstr, sizeof(p->dop.dialstr), "P%s", c);
         break;
      case SIG_FGC_CAMAMF:
      case SIG_FEATB:
         snprintf(p->dop.dialstr, sizeof(p->dop.dialstr), "M*%s#", c);
         break;
      default:
         if (p->pulse)
            snprintf(p->dop.dialstr, sizeof(p->dop.dialstr), "P%sw", c);
         else
            snprintf(p->dop.dialstr, sizeof(p->dop.dialstr), "T%sw", c);
         break;
      }

      if (p->echotraining && (strlen(p->dop.dialstr) > 4)) {
         memset(p->echorest, 'w', sizeof(p->echorest) - 1);
         strcpy(p->echorest + (p->echotraining / 400) + 1, p->dop.dialstr + strlen(p->dop.dialstr) - 2);
         p->echorest[sizeof(p->echorest) - 1] = '\0';
         p->echobreak = 1;
         p->dop.dialstr[strlen(p->dop.dialstr)-2] = '\0';
      } else
         p->echobreak = 0;
      if (!res) {
         if (ioctl(p->subs[SUB_REAL].dfd, DAHDI_DIAL, &p->dop)) {
            int saveerr = errno;

            x = DAHDI_ONHOOK;
            ioctl(p->subs[SUB_REAL].dfd, DAHDI_HOOK, &x);
            ast_log(LOG_WARNING, "Dialing failed on channel %d: %s\n", p->channel, strerror(saveerr));
            ast_mutex_unlock(&p->lock);
            return -1;
         }
      } else
         ast_debug(1, "Deferring dialing...\n");

      p->dialing = 1;
      if (ast_strlen_zero(c))
         p->dialednone = 1;
      ast_setstate(ast, AST_STATE_DIALING);
      break;
   case 0:
      /* Special pseudo -- automatically up*/
      ast_setstate(ast, AST_STATE_UP);
      break;      
   case SIG_PRI:
   case SIG_BRI:
   case SIG_BRI_PTMP:
   case SIG_SS7:
      /* We'll get it in a moment -- but use dialdest to store pre-setup_ack digits */
      p->dialdest[0] = '\0';
      p->dialing = 1;
      break;
   default:
      ast_debug(1, "not yet implemented\n");
      ast_mutex_unlock(&p->lock);
      return -1;
   }
#ifdef HAVE_SS7
   if (p->ss7) {
      char ss7_called_nai;
      int called_nai_strip;
      char ss7_calling_nai;
      int calling_nai_strip;
      const char *charge_str = NULL;
      const char *gen_address = NULL;
      const char *gen_digits = NULL;
      const char *gen_dig_type = NULL;
      const char *gen_dig_scheme = NULL;
      const char *gen_name = NULL;
      const char *jip_digits = NULL;
      const char *lspi_ident = NULL;
      const char *rlt_flag = NULL;
      const char *call_ref_id = NULL;
      const char *call_ref_pc = NULL;
      const char *send_far = NULL;

      c = strchr(dest, '/');
      if (c) {
         c++;
      } else {
         c = "";
      }
      if (strlen(c) < p->stripmsd) {
         ast_log(LOG_WARNING, "Number '%s' is shorter than stripmsd (%d)\n", c, p->stripmsd);
         ast_mutex_unlock(&p->lock);
         return -1;
      }

      if (!p->hidecallerid) {
         l = ast->cid.cid_num;
      } else {
         l = NULL;
      }

      if (ss7_grab(p, p->ss7)) {
         ast_log(LOG_WARNING, "Failed to grab SS7!\n");
         ast_mutex_unlock(&p->lock);
         return -1;
      }
      p->digital = IS_DIGITAL(ast->transfercapability);
      p->ss7call = isup_new_call(p->ss7->ss7);

      if (!p->ss7call) {
         ss7_rel(p->ss7);
         ast_mutex_unlock(&p->lock);
         ast_log(LOG_ERROR, "Unable to allocate new SS7 call!\n");
         return -1;
      }

      called_nai_strip = 0;
      ss7_called_nai = p->ss7->called_nai;
      if (ss7_called_nai == SS7_NAI_DYNAMIC) { /* compute dynamically */
         if (strncmp(c + p->stripmsd, p->ss7->internationalprefix, strlen(p->ss7->internationalprefix)) == 0) {
            called_nai_strip = strlen(p->ss7->internationalprefix);
            ss7_called_nai = SS7_NAI_INTERNATIONAL;
         } else if (strncmp(c + p->stripmsd, p->ss7->nationalprefix, strlen(p->ss7->nationalprefix)) == 0) {
            called_nai_strip = strlen(p->ss7->nationalprefix);
            ss7_called_nai = SS7_NAI_NATIONAL;
         } else {
            ss7_called_nai = SS7_NAI_SUBSCRIBER;
         }
      }
      isup_set_called(p->ss7call, c + p->stripmsd + called_nai_strip, ss7_called_nai, p->ss7->ss7);

      calling_nai_strip = 0;
      ss7_calling_nai = p->ss7->calling_nai;
      if ((l != NULL) && (ss7_calling_nai == SS7_NAI_DYNAMIC)) { /* compute dynamically */
         if (strncmp(l, p->ss7->internationalprefix, strlen(p->ss7->internationalprefix)) == 0) {
            calling_nai_strip = strlen(p->ss7->internationalprefix);
            ss7_calling_nai = SS7_NAI_INTERNATIONAL;
         } else if (strncmp(l, p->ss7->nationalprefix, strlen(p->ss7->nationalprefix)) == 0) {
            calling_nai_strip = strlen(p->ss7->nationalprefix);
            ss7_calling_nai = SS7_NAI_NATIONAL;
         } else {
            ss7_calling_nai = SS7_NAI_SUBSCRIBER;
         }
      }
      isup_set_calling(p->ss7call, l ? (l + calling_nai_strip) : NULL, ss7_calling_nai,
         p->use_callingpres ? cid_pres2ss7pres(ast->cid.cid_pres) : (l ? SS7_PRESENTATION_ALLOWED : SS7_PRESENTATION_RESTRICTED),
         p->use_callingpres ? cid_pres2ss7screen(ast->cid.cid_pres) : SS7_SCREENING_USER_PROVIDED );

      isup_set_oli(p->ss7call, ast->cid.cid_ani2);
      isup_init_call(p->ss7->ss7, p->ss7call, p->cic, p->dpc);

      ast_channel_lock(ast);
      /* Set the charge number if it is set */
      charge_str = pbx_builtin_getvar_helper(ast, "SS7_CHARGE_NUMBER");
      if (charge_str)
         isup_set_charge(p->ss7call, charge_str, SS7_ANI_CALLING_PARTY_SUB_NUMBER, 0x10);
      
      gen_address = pbx_builtin_getvar_helper(ast, "SS7_GENERIC_ADDRESS");
      if (gen_address)
         isup_set_gen_address(p->ss7call, gen_address, p->gen_add_nai,p->gen_add_pres_ind, p->gen_add_num_plan,p->gen_add_type); /* need to add some types here for NAI,PRES,TYPE */
      
      gen_digits = pbx_builtin_getvar_helper(ast, "SS7_GENERIC_DIGITS");
      gen_dig_type = pbx_builtin_getvar_helper(ast, "SS7_GENERIC_DIGTYPE");
      gen_dig_scheme = pbx_builtin_getvar_helper(ast, "SS7_GENERIC_DIGSCHEME");
      if (gen_digits)
         isup_set_gen_digits(p->ss7call, gen_digits, atoi(gen_dig_type), atoi(gen_dig_scheme)); 
      
      gen_name = pbx_builtin_getvar_helper(ast, "SS7_GENERIC_NAME");
      if (gen_name)
         isup_set_generic_name(p->ss7call, gen_name, GEN_NAME_TYPE_CALLING_NAME, GEN_NAME_AVAIL_AVAILABLE, GEN_NAME_PRES_ALLOWED);

      jip_digits = pbx_builtin_getvar_helper(ast, "SS7_JIP");
      if (jip_digits)
         isup_set_jip_digits(p->ss7call, jip_digits);
      
      lspi_ident = pbx_builtin_getvar_helper(ast, "SS7_LSPI_IDENT");
      if (lspi_ident)
         isup_set_lspi(p->ss7call, lspi_ident, 0x18, 0x7, 0x00); 
      
      rlt_flag = pbx_builtin_getvar_helper(ast, "SS7_RLT_ON");
      if ((rlt_flag) && ((strncmp("NO", rlt_flag, strlen(rlt_flag))) != 0 )) {
         isup_set_lspi(p->ss7call, rlt_flag, 0x18, 0x7, 0x00); /* Setting for Nortel DMS-250/500 */
      }
      
      call_ref_id = pbx_builtin_getvar_helper(ast, "SS7_CALLREF_IDENT");
      call_ref_pc = pbx_builtin_getvar_helper(ast, "SS7_CALLREF_PC");
      if (call_ref_id && call_ref_pc) {
         isup_set_callref(p->ss7call, atoi(call_ref_id),
                call_ref_pc ? atoi(call_ref_pc) : 0);
      }
      
      send_far = pbx_builtin_getvar_helper(ast, "SS7_SEND_FAR");
      if ((send_far) && ((strncmp("NO", send_far, strlen(send_far))) != 0 ))
         (isup_far(p->ss7->ss7, p->ss7call));
      
      ast_channel_unlock(ast);

      isup_iam(p->ss7->ss7, p->ss7call);
      ast_setstate(ast, AST_STATE_DIALING);
      ss7_rel(p->ss7);
   }
#endif /* HAVE_SS7 */
#ifdef HAVE_PRI
   if (p->pri) {
      struct pri_sr *sr;
#ifdef SUPPORT_USERUSER
      const char *useruser;
#endif
      int pridialplan;
      int dp_strip;
      int prilocaldialplan;
      int ldp_strip;
      int exclusive;
      const char *rr_str;
      int redirect_reason;

      c = strchr(dest, '/');
      if (c) {
         c++;
      } else {
         c = "";
      }

      l = NULL;
      n = NULL;
      if (!p->hidecallerid) {
         l = ast->cid.cid_num;
         if (!p->hidecalleridname) {
            n = ast->cid.cid_name;
         }
      }

      if (strlen(c) < p->stripmsd) {
         ast_log(LOG_WARNING, "Number '%s' is shorter than stripmsd (%d)\n", c, p->stripmsd);
         ast_mutex_unlock(&p->lock);
         return -1;
      }
      if (mysig != SIG_FXSKS) {
         p->dop.op = DAHDI_DIAL_OP_REPLACE;
         s = strchr(c + p->stripmsd, 'w');
         if (s) {
            if (strlen(s) > 1)
               snprintf(p->dop.dialstr, sizeof(p->dop.dialstr), "T%s", s);
            else
               p->dop.dialstr[0] = '\0';
            *s = '\0';
         } else {
            p->dop.dialstr[0] = '\0';
         }
      }
      if (pri_grab(p, p->pri)) {
         ast_log(LOG_WARNING, "Failed to grab PRI!\n");
         ast_mutex_unlock(&p->lock);
         return -1;
      }
      if (!(p->call = pri_new_call(p->pri->pri))) {
         ast_log(LOG_WARNING, "Unable to create call on channel %d\n", p->channel);
         pri_rel(p->pri);
         ast_mutex_unlock(&p->lock);
         return -1;
      }
      if (!(sr = pri_sr_new())) {
         ast_log(LOG_WARNING, "Failed to allocate setup request channel %d\n", p->channel);
         pri_rel(p->pri);
         ast_mutex_unlock(&p->lock);
      }
      if (p->bearer || (mysig == SIG_FXSKS)) {
         if (p->bearer) {
            ast_debug(1, "Oooh, I have a bearer on %d (%d:%d)\n", PVT_TO_CHANNEL(p->bearer), p->bearer->logicalspan, p->bearer->channel);
            p->bearer->call = p->call;
         } else
            ast_debug(1, "I'm being setup with no bearer right now...\n");

         pri_set_crv(p->pri->pri, p->call, p->channel, 0);
      }
      p->digital = IS_DIGITAL(ast->transfercapability);

      /* Should the picked channel be used exclusively? */
      if (p->priexclusive || p->pri->nodetype == PRI_NETWORK) {
         exclusive = 1;
      } else {
         exclusive = 0;
      }
      
      pri_sr_set_channel(sr, p->bearer ? PVT_TO_CHANNEL(p->bearer) : PVT_TO_CHANNEL(p), exclusive, 1);
      pri_sr_set_bearer(sr, p->digital ? PRI_TRANS_CAP_DIGITAL : ast->transfercapability, 
               (p->digital ? -1 : 
                  ((p->law == DAHDI_LAW_ALAW) ? PRI_LAYER_1_ALAW : PRI_LAYER_1_ULAW)));
      if (p->pri->facilityenable)
         pri_facility_enable(p->pri->pri);

      ast_verb(3, "Requested transfer capability: 0x%.2x - %s\n", ast->transfercapability, ast_transfercapability2str(ast->transfercapability));
      dp_strip = 0;
      pridialplan = p->pri->dialplan - 1;
      if (pridialplan == -2 || pridialplan == -3) { /* compute dynamically */
         if (strncmp(c + p->stripmsd, p->pri->internationalprefix, strlen(p->pri->internationalprefix)) == 0) {
            if (pridialplan == -2) {
               dp_strip = strlen(p->pri->internationalprefix);
            }
            pridialplan = PRI_INTERNATIONAL_ISDN;
         } else if (strncmp(c + p->stripmsd, p->pri->nationalprefix, strlen(p->pri->nationalprefix)) == 0) {
            if (pridialplan == -2) {
               dp_strip = strlen(p->pri->nationalprefix);
            }
            pridialplan = PRI_NATIONAL_ISDN;
         } else {
            pridialplan = PRI_LOCAL_ISDN;
         }
      }
      while (c[p->stripmsd] > '9' && c[p->stripmsd] != '*' && c[p->stripmsd] != '#') {
         switch (c[p->stripmsd]) {
         case 'U':
            pridialplan = (PRI_TON_UNKNOWN << 4) | (pridialplan & 0xf);
            break;
         case 'I':
            pridialplan = (PRI_TON_INTERNATIONAL << 4) | (pridialplan & 0xf);
            break;
         case 'N':
            pridialplan = (PRI_TON_NATIONAL << 4) | (pridialplan & 0xf);
            break;
         case 'L':
            pridialplan = (PRI_TON_NET_SPECIFIC << 4) | (pridialplan & 0xf);
            break;
         case 'S':
            pridialplan = (PRI_TON_SUBSCRIBER << 4) | (pridialplan & 0xf);
            break;
         case 'V':
            pridialplan = (PRI_TON_ABBREVIATED << 4) | (pridialplan & 0xf);
            break;
         case 'R':
            pridialplan = (PRI_TON_RESERVED << 4) | (pridialplan & 0xf);
            break;
         case 'u':
            pridialplan = PRI_NPI_UNKNOWN | (pridialplan & 0xf0);
            break;
         case 'e':
            pridialplan = PRI_NPI_E163_E164 | (pridialplan & 0xf0);
            break;
         case 'x':
            pridialplan = PRI_NPI_X121 | (pridialplan & 0xf0);
            break;
         case 'f':
            pridialplan = PRI_NPI_F69 | (pridialplan & 0xf0);
            break;
         case 'n':
            pridialplan = PRI_NPI_NATIONAL | (pridialplan & 0xf0);
            break;
         case 'p':
            pridialplan = PRI_NPI_PRIVATE | (pridialplan & 0xf0);
            break;
         case 'r':
            pridialplan = PRI_NPI_RESERVED | (pridialplan & 0xf0);
            break;
         default:
            if (isalpha(c[p->stripmsd])) {
               ast_log(LOG_WARNING, "Unrecognized pridialplan %s modifier: %c\n",
                  c[p->stripmsd] > 'Z' ? "NPI" : "TON", c[p->stripmsd]);
            }
            break;
         }
         c++;
      }
      pri_sr_set_called(sr, c + p->stripmsd + dp_strip, pridialplan, s ? 1 : 0);

      ldp_strip = 0;
      prilocaldialplan = p->pri->localdialplan - 1;
      if ((l != NULL) && (prilocaldialplan == -2 || prilocaldialplan == -3)) { /* compute dynamically */
         if (strncmp(l, p->pri->internationalprefix, strlen(p->pri->internationalprefix)) == 0) {
            if (prilocaldialplan == -2) {
               ldp_strip = strlen(p->pri->internationalprefix);
            }
            prilocaldialplan = PRI_INTERNATIONAL_ISDN;
         } else if (strncmp(l, p->pri->nationalprefix, strlen(p->pri->nationalprefix)) == 0) {
            if (prilocaldialplan == -2) {
               ldp_strip = strlen(p->pri->nationalprefix);
            }
            prilocaldialplan = PRI_NATIONAL_ISDN;
         } else {
            prilocaldialplan = PRI_LOCAL_ISDN;
         }
      }
      if (l != NULL) {
         while (*l > '9' && *l != '*' && *l != '#') {
            switch (*l) {
            case 'U':
               prilocaldialplan = (PRI_TON_UNKNOWN << 4) | (prilocaldialplan & 0xf);
               break;
            case 'I':
               prilocaldialplan = (PRI_TON_INTERNATIONAL << 4) | (prilocaldialplan & 0xf);
               break;
            case 'N':
               prilocaldialplan = (PRI_TON_NATIONAL << 4) | (prilocaldialplan & 0xf);
               break;
            case 'L':
               prilocaldialplan = (PRI_TON_NET_SPECIFIC << 4) | (prilocaldialplan & 0xf);
               break;
            case 'S':
               prilocaldialplan = (PRI_TON_SUBSCRIBER << 4) | (prilocaldialplan & 0xf);
               break;
            case 'V':
               prilocaldialplan = (PRI_TON_ABBREVIATED << 4) | (prilocaldialplan & 0xf);
               break;
            case 'R':
               prilocaldialplan = (PRI_TON_RESERVED << 4) | (prilocaldialplan & 0xf);
               break;
            case 'u':
               prilocaldialplan = PRI_NPI_UNKNOWN | (prilocaldialplan & 0xf0);
               break;
            case 'e':
               prilocaldialplan = PRI_NPI_E163_E164 | (prilocaldialplan & 0xf0);
               break;
            case 'x':
               prilocaldialplan = PRI_NPI_X121 | (prilocaldialplan & 0xf0);
               break;
            case 'f':
               prilocaldialplan = PRI_NPI_F69 | (prilocaldialplan & 0xf0);
               break;
            case 'n':
               prilocaldialplan = PRI_NPI_NATIONAL | (prilocaldialplan & 0xf0);
               break;
            case 'p':
               prilocaldialplan = PRI_NPI_PRIVATE | (prilocaldialplan & 0xf0);
               break;
            case 'r':
               prilocaldialplan = PRI_NPI_RESERVED | (prilocaldialplan & 0xf0);
               break;
            default:
               if (isalpha(*l)) {
                  ast_log(LOG_WARNING,
                     "Unrecognized prilocaldialplan %s modifier: %c\n",
                     *l > 'Z' ? "NPI" : "TON", *l);
               }
               break;
            }
            l++;
         }
      }
      pri_sr_set_caller(sr, l ? (l + ldp_strip) : NULL, n, prilocaldialplan,
         p->use_callingpres ? ast->cid.cid_pres : (l ? PRES_ALLOWED_USER_NUMBER_PASSED_SCREEN : PRES_NUMBER_NOT_AVAILABLE));
      if ((rr_str = pbx_builtin_getvar_helper(ast, "PRIREDIRECTREASON"))) {
         if (!strcasecmp(rr_str, "UNKNOWN"))
            redirect_reason = 0;
         else if (!strcasecmp(rr_str, "BUSY"))
            redirect_reason = 1;
         else if (!strcasecmp(rr_str, "NO_REPLY") || !strcasecmp(rr_str, "NOANSWER"))
         /* the NOANSWER is to match diversion-reason from chan_sip, (which never reads PRIREDIRECTREASON) */
            redirect_reason = 2;
         else if (!strcasecmp(rr_str, "UNCONDITIONAL"))
            redirect_reason = 15;
         else
            redirect_reason = PRI_REDIR_UNCONDITIONAL;
      } else
         redirect_reason = PRI_REDIR_UNCONDITIONAL;
      pri_sr_set_redirecting(sr, ast->cid.cid_rdnis, p->pri->localdialplan - 1, PRES_ALLOWED_USER_NUMBER_PASSED_SCREEN, redirect_reason);

#ifdef SUPPORT_USERUSER
      /* User-user info */
      useruser = pbx_builtin_getvar_helper(p->owner, "USERUSERINFO");

      if (useruser)
         pri_sr_set_useruser(sr, useruser);
#endif

      if (pri_setup(p->pri->pri, p->call, sr)) {
         ast_log(LOG_WARNING, "Unable to setup call to %s (using %s)\n", 
            c + p->stripmsd + dp_strip, dialplan2str(p->pri->dialplan));
         pri_rel(p->pri);
         ast_mutex_unlock(&p->lock);
         pri_sr_free(sr);
         return -1;
      }
      pri_sr_free(sr);
      ast_setstate(ast, AST_STATE_DIALING);
      pri_rel(p->pri);
   }
#endif      
   ast_mutex_unlock(&p->lock);
   return 0;
}

static void destroy_dahdi_pvt(struct dahdi_pvt **pvt)
{
   struct dahdi_pvt *p = *pvt;
   /* Remove channel from the list */
   if (p->prev)
      p->prev->next = p->next;
   if (p->next)
      p->next->prev = p->prev;
   if (p->use_smdi)
      ast_smdi_interface_unref(p->smdi_iface);
   if (p->mwi_event_sub)
      ast_event_unsubscribe(p->mwi_event_sub);
   if (p->vars) {
      ast_variables_destroy(p->vars);
   }
   ast_mutex_destroy(&p->lock);
   dahdi_close_sub(p, SUB_REAL);
   if (p->owner)
      p->owner->tech_pvt = NULL;
   free(p);
   *pvt = NULL;
}

static int destroy_channel(struct dahdi_pvt *prev, struct dahdi_pvt *cur, int now)
{
   int owned = 0;
   int i = 0;

   if (!now) {
      if (cur->owner) {
         owned = 1;
      }

      for (i = 0; i < 3; i++) {
         if (cur->subs[i].owner) {
            owned = 1;
         }
      }
      if (!owned) {
         if (prev) {
            prev->next = cur->next;
            if (prev->next)
               prev->next->prev = prev;
            else
               ifend = prev;
         } else {
            iflist = cur->next;
            if (iflist)
               iflist->prev = NULL;
            else
               ifend = NULL;
         }
         destroy_dahdi_pvt(&cur);
      }
   } else {
      if (prev) {
         prev->next = cur->next;
         if (prev->next)
            prev->next->prev = prev;
         else
            ifend = prev;
      } else {
         iflist = cur->next;
         if (iflist)
            iflist->prev = NULL;
         else
            ifend = NULL;
      }
      destroy_dahdi_pvt(&cur);
   }
   return 0;
}

static void destroy_all_channels(void)
{
   int x;
   struct dahdi_pvt *p, *pl;

   while (num_restart_pending) {
      usleep(1);
   }

   ast_mutex_lock(&iflock);
   /* Destroy all the interfaces and free their memory */
   p = iflist;
   while (p) {
      /* Free any callerid */
      if (p->cidspill)
         ast_free(p->cidspill);
      pl = p;
      p = p->next;
      x = pl->channel;
      /* Free associated memory */
      if (pl)
         destroy_dahdi_pvt(&pl);
      if (option_verbose > 2) 
         ast_verbose(VERBOSE_PREFIX_2 "Unregistered channel %d\n", x);
   }
   iflist = NULL;
   ifcount = 0;
   ast_mutex_unlock(&iflock);
}

#ifdef HAVE_PRI
static char *dahdi_send_keypad_facility_app = "DAHDISendKeypadFacility";

static char *dahdi_send_keypad_facility_synopsis = "Send digits out of band over a PRI";

static char *dahdi_send_keypad_facility_descrip = 
"  DAHDISendKeypadFacility(): This application will send the given string of digits in a Keypad Facility\n"
"  IE over the current channel.\n";

static int dahdi_send_keypad_facility_exec(struct ast_channel *chan, void *data)
{
   /* Data will be our digit string */
   struct dahdi_pvt *p;
   char *digits = (char *) data;

   if (ast_strlen_zero(digits)) {
      ast_debug(1, "No digit string sent to application!\n");
      return -1;
   }

   p = (struct dahdi_pvt *)chan->tech_pvt;

   if (!p) {
      ast_debug(1, "Unable to find technology private\n");
      return -1;
   }

   ast_mutex_lock(&p->lock);

   if (!p->pri || !p->call) {
      ast_debug(1, "Unable to find pri or call on channel!\n");
      ast_mutex_unlock(&p->lock);
      return -1;
   }

   if (!pri_grab(p, p->pri)) {
      pri_keypad_facility(p->pri->pri, p->call, digits);
      pri_rel(p->pri);
   } else {
      ast_debug(1, "Unable to grab pri to send keypad facility!\n");
      ast_mutex_unlock(&p->lock);
      return -1;
   }

   ast_mutex_unlock(&p->lock);

   return 0;
}

static int pri_is_up(struct dahdi_pri *pri)
{
   int x;
   for (x = 0; x < NUM_DCHANS; x++) {
      if (pri->dchanavail[x] == DCHAN_AVAILABLE)
         return 1;
   }
   return 0;
}

static int pri_assign_bearer(struct dahdi_pvt *crv, struct dahdi_pri *pri, struct dahdi_pvt *bearer)
{
   bearer->owner = &inuse;
   bearer->realcall = crv;
   crv->subs[SUB_REAL].dfd = bearer->subs[SUB_REAL].dfd;
   if (crv->subs[SUB_REAL].owner)
      ast_channel_set_fd(crv->subs[SUB_REAL].owner, 0, crv->subs[SUB_REAL].dfd);
   crv->bearer = bearer;
   crv->call = bearer->call;
   crv->pri = pri;
   return 0;
}

static char *pri_order(int level)
{
   switch (level) {
   case 0:
      return "Primary";
   case 1:
      return "Secondary";
   case 2:
      return "Tertiary";
   case 3:
      return "Quaternary";
   default:
      return "<Unknown>";
   }     
}

/* Returns fd of the active dchan */
static int pri_active_dchan_fd(struct dahdi_pri *pri)
{
   int x = -1;

   for (x = 0; x < NUM_DCHANS; x++) {
      if ((pri->dchans[x] == pri->pri))
         break;
   }

   return pri->fds[x];
}

static int pri_find_dchan(struct dahdi_pri *pri)
{
   int oldslot = -1;
   struct pri *old;
   int newslot = -1;
   int x;
   old = pri->pri;
   for (x = 0; x < NUM_DCHANS; x++) {
      if ((pri->dchanavail[x] == DCHAN_AVAILABLE) && (newslot < 0))
         newslot = x;
      if (pri->dchans[x] == old) {
         oldslot = x;
      }
   }
   if (newslot < 0) {
      newslot = 0;
      ast_log(LOG_WARNING, "No D-channels available!  Using Primary channel %d as D-channel anyway!\n",
         pri->dchannels[newslot]);
   }
   if (old && (oldslot != newslot))
      ast_log(LOG_NOTICE, "Switching from from d-channel %d to channel %d!\n",
         pri->dchannels[oldslot], pri->dchannels[newslot]);
   pri->pri = pri->dchans[newslot];
   return 0;
}
#endif

static int dahdi_hangup(struct ast_channel *ast)
{
   int res;
   int index,x, law;
   /*static int restore_gains(struct dahdi_pvt *p);*/
   struct dahdi_pvt *p = ast->tech_pvt;
   struct dahdi_pvt *tmp = NULL;
   struct dahdi_pvt *prev = NULL;
   struct dahdi_params par;

   ast_debug(1, "dahdi_hangup(%s)\n", ast->name);
   if (!ast->tech_pvt) {
      ast_log(LOG_WARNING, "Asked to hangup channel not connected\n");
      return 0;
   }
   
   ast_mutex_lock(&p->lock);
   
   index = dahdi_get_index(ast, p, 1);

   if ((p->sig == SIG_PRI) || (p->sig == SIG_SS7) || (p->sig == SIG_BRI) || (p->sig == SIG_BRI_PTMP)) {
      x = 1;
      ast_channel_setoption(ast,AST_OPTION_AUDIO_MODE,&x,sizeof(char),0);
      p->cid_num[0] = '\0';
      p->cid_name[0] = '\0';
   }

   x = 0;
   dahdi_confmute(p, 0);
   restore_gains(p);
   if (p->origcid_num) {
      ast_copy_string(p->cid_num, p->origcid_num, sizeof(p->cid_num));
      ast_free(p->origcid_num);
      p->origcid_num = NULL;
   }  
   if (p->origcid_name) {
      ast_copy_string(p->cid_name, p->origcid_name, sizeof(p->cid_name));
      ast_free(p->origcid_name);
      p->origcid_name = NULL;
   }  
   if (p->dsp)
      ast_dsp_digitmode(p->dsp, DSP_DIGITMODE_DTMF | p->dtmfrelax);
   p->exten[0] = '\0';

   ast_debug(1, "Hangup: channel: %d index = %d, normal = %d, callwait = %d, thirdcall = %d\n",
      p->channel, index, p->subs[SUB_REAL].dfd, p->subs[SUB_CALLWAIT].dfd, p->subs[SUB_THREEWAY].dfd);
   p->ignoredtmf = 0;
   
   if (index > -1) {
      /* Real channel, do some fixup */
      p->subs[index].owner = NULL;
      p->subs[index].needanswer = 0;
      p->subs[index].needflash = 0;
      p->subs[index].needringing = 0;
      p->subs[index].needbusy = 0;
      p->subs[index].needcongestion = 0;
      p->subs[index].linear = 0;
      p->subs[index].needcallerid = 0;
      p->polarity = POLARITY_IDLE;
      dahdi_setlinear(p->subs[index].dfd, 0);
      if (index == SUB_REAL) {
         if ((p->subs[SUB_CALLWAIT].dfd > -1) && (p->subs[SUB_THREEWAY].dfd > -1)) {
            ast_debug(1, "Normal call hung up with both three way call and a call waiting call in place?\n");
            if (p->subs[SUB_CALLWAIT].inthreeway) {
               /* We had flipped over to answer a callwait and now it's gone */
               ast_debug(1, "We were flipped over to the callwait, moving back and unowning.\n");
               /* Move to the call-wait, but un-own us until they flip back. */
               swap_subs(p, SUB_CALLWAIT, SUB_REAL);
               unalloc_sub(p, SUB_CALLWAIT);
               p->owner = NULL;
            } else {
               /* The three way hung up, but we still have a call wait */
               ast_debug(1, "We were in the threeway and have a callwait still.  Ditching the threeway.\n");
               swap_subs(p, SUB_THREEWAY, SUB_REAL);
               unalloc_sub(p, SUB_THREEWAY);
               if (p->subs[SUB_REAL].inthreeway) {
                  /* This was part of a three way call.  Immediately make way for
                     another call */
                  ast_debug(1, "Call was complete, setting owner to former third call\n");
                  p->owner = p->subs[SUB_REAL].owner;
               } else {
                  /* This call hasn't been completed yet...  Set owner to NULL */
                  ast_debug(1, "Call was incomplete, setting owner to NULL\n");
                  p->owner = NULL;
               }
               p->subs[SUB_REAL].inthreeway = 0;
            }
         } else if (p->subs[SUB_CALLWAIT].dfd > -1) {
            /* Move to the call-wait and switch back to them. */
            swap_subs(p, SUB_CALLWAIT, SUB_REAL);
            unalloc_sub(p, SUB_CALLWAIT);
            p->owner = p->subs[SUB_REAL].owner;
            if (p->owner->_state != AST_STATE_UP)
               p->subs[SUB_REAL].needanswer = 1;
            if (ast_bridged_channel(p->subs[SUB_REAL].owner))
               ast_queue_control(p->subs[SUB_REAL].owner, AST_CONTROL_UNHOLD);
         } else if (p->subs[SUB_THREEWAY].dfd > -1) {
            swap_subs(p, SUB_THREEWAY, SUB_REAL);
            unalloc_sub(p, SUB_THREEWAY);
            if (p->subs[SUB_REAL].inthreeway) {
               /* This was part of a three way call.  Immediately make way for
                  another call */
               ast_debug(1, "Call was complete, setting owner to former third call\n");
               p->owner = p->subs[SUB_REAL].owner;
            } else {
               /* This call hasn't been completed yet...  Set owner to NULL */
               ast_debug(1, "Call was incomplete, setting owner to NULL\n");
               p->owner = NULL;
            }
            p->subs[SUB_REAL].inthreeway = 0;
         }
      } else if (index == SUB_CALLWAIT) {
         /* Ditch the holding callwait call, and immediately make it availabe */
         if (p->subs[SUB_CALLWAIT].inthreeway) {
            /* This is actually part of a three way, placed on hold.  Place the third part
               on music on hold now */
            if (p->subs[SUB_THREEWAY].owner && ast_bridged_channel(p->subs[SUB_THREEWAY].owner)) {
               ast_queue_control_data(p->subs[SUB_THREEWAY].owner, AST_CONTROL_HOLD, 
                  S_OR(p->mohsuggest, NULL),
                  !ast_strlen_zero(p->mohsuggest) ? strlen(p->mohsuggest) + 1 : 0);
            }
            p->subs[SUB_THREEWAY].inthreeway = 0;
            /* Make it the call wait now */
            swap_subs(p, SUB_CALLWAIT, SUB_THREEWAY);
            unalloc_sub(p, SUB_THREEWAY);
         } else
            unalloc_sub(p, SUB_CALLWAIT);
      } else if (index == SUB_THREEWAY) {
         if (p->subs[SUB_CALLWAIT].inthreeway) {
            /* The other party of the three way call is currently in a call-wait state.
               Start music on hold for them, and take the main guy out of the third call */
            if (p->subs[SUB_CALLWAIT].owner && ast_bridged_channel(p->subs[SUB_CALLWAIT].owner)) {
               ast_queue_control_data(p->subs[SUB_CALLWAIT].owner, AST_CONTROL_HOLD, 
                  S_OR(p->mohsuggest, NULL),
                  !ast_strlen_zero(p->mohsuggest) ? strlen(p->mohsuggest) + 1 : 0);
            }
            p->subs[SUB_CALLWAIT].inthreeway = 0;
         }
         p->subs[SUB_REAL].inthreeway = 0;
         /* If this was part of a three way call index, let us make
            another three way call */
         unalloc_sub(p, SUB_THREEWAY);
      } else {
         /* This wasn't any sort of call, but how are we an index? */
         ast_log(LOG_WARNING, "Index found but not any type of call?\n");
      }
   }

   if (!p->subs[SUB_REAL].owner && !p->subs[SUB_CALLWAIT].owner && !p->subs[SUB_THREEWAY].owner) {
      p->owner = NULL;
      p->ringt = 0;
      p->distinctivering = 0;
      p->confirmanswer = 0;
      p->cidrings = 1;
      p->outgoing = 0;
      p->digital = 0;
      p->faxhandled = 0;
      p->pulsedial = 0;
      p->onhooktime = time(NULL);
#if defined(HAVE_PRI) || defined(HAVE_SS7)
      p->proceeding = 0;
      p->dialing = 0;
      p->progress = 0;
      p->alerting = 0;
      p->setup_ack = 0;
      p->rlt = 0;
#endif      
      if (p->dsp) {
         ast_dsp_free(p->dsp);
         p->dsp = NULL;
      }

      law = DAHDI_LAW_DEFAULT;
      res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_SETLAW, &law);
      if (res < 0) 
         ast_log(LOG_WARNING, "Unable to set law on channel %d to default: %s\n", p->channel, strerror(errno));
      /* Perform low level hangup if no owner left */
#ifdef HAVE_SS7
      if (p->ss7) {
         if (p->ss7call) {
            if (!ss7_grab(p, p->ss7)) {
               if (!p->alreadyhungup) {
                  const char *cause = pbx_builtin_getvar_helper(ast,"SS7_CAUSE");
                  int icause = ast->hangupcause ? ast->hangupcause : -1;

                  if (cause) {
                     if (atoi(cause))
                        icause = atoi(cause);
                  }
                  isup_rel(p->ss7->ss7, p->ss7call, icause);
                  ss7_rel(p->ss7);
                  p->alreadyhungup = 1;
               } else
                  ast_log(LOG_WARNING, "Trying to hangup twice!\n");
            } else {
               ast_log(LOG_WARNING, "Unable to grab SS7 on CIC %d\n", p->cic);
               res = -1;
            }
         }
      }
#endif
#ifdef HAVE_PRI
      if (p->pri) {
#ifdef SUPPORT_USERUSER
         const char *useruser = pbx_builtin_getvar_helper(ast,"USERUSERINFO");
#endif

         /* Make sure we have a call (or REALLY have a call in the case of a PRI) */
         if (p->call && (!p->bearer || (p->bearer->call == p->call))) {
            if (!pri_grab(p, p->pri)) {
               if (p->alreadyhungup) {
                  ast_debug(1, "Already hungup...  Calling hangup once, and clearing call\n");

#ifdef SUPPORT_USERUSER
                  pri_call_set_useruser(p->call, useruser);
#endif

                  pri_hangup(p->pri->pri, p->call, -1);
                  p->call = NULL;
                  if (p->bearer) 
                     p->bearer->call = NULL;
               } else {
                  const char *cause = pbx_builtin_getvar_helper(ast,"PRI_CAUSE");
                  int icause = ast->hangupcause ? ast->hangupcause : -1;
                  ast_debug(1, "Not yet hungup...  Calling hangup once with icause, and clearing call\n");

#ifdef SUPPORT_USERUSER
                  pri_call_set_useruser(p->call, useruser);
#endif

                  p->alreadyhungup = 1;
                  if (p->bearer)
                     p->bearer->alreadyhungup = 1;
                  if (cause) {
                     if (atoi(cause))
                        icause = atoi(cause);
                  }
                  pri_hangup(p->pri->pri, p->call, icause);
               }
               if (res < 0) 
                  ast_log(LOG_WARNING, "pri_disconnect failed\n");
               pri_rel(p->pri);        
            } else {
               ast_log(LOG_WARNING, "Unable to grab PRI on span %d\n", p->span);
               res = -1;
            }
         } else {
            if (p->bearer)
               ast_debug(1, "Bearer call is %p, while ours is still %p\n", p->bearer->call, p->call);
            p->call = NULL;
            res = 0;
         }
      }
#endif
      if (p->sig && ((p->sig != SIG_PRI) && (p->sig != SIG_SS7) && (p->sig != SIG_BRI) && (p->sig != SIG_BRI_PTMP)))
         res = dahdi_set_hook(p->subs[SUB_REAL].dfd, DAHDI_ONHOOK);
      if (res < 0) {
         ast_log(LOG_WARNING, "Unable to hangup line %s\n", ast->name);
      }
      switch (p->sig) {
      case SIG_FXOGS:
      case SIG_FXOLS:
      case SIG_FXOKS:
         memset(&par, 0, sizeof(par));
         res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_GET_PARAMS, &par);
         if (!res) {
#if 0
            ast_debug(1, "Hanging up channel %d, offhook = %d\n", p->channel, par.rxisoffhook);
#endif
            /* If they're off hook, try playing congestion */
            if ((par.rxisoffhook) && (!(p->radio || (p->oprmode < 0))))
               tone_zone_play_tone(p->subs[SUB_REAL].dfd, DAHDI_TONE_CONGESTION);
            else
               tone_zone_play_tone(p->subs[SUB_REAL].dfd, -1);
         }
         break;
      case SIG_FXSGS:
      case SIG_FXSLS:
      case SIG_FXSKS:
         /* Make sure we're not made available for at least two seconds assuming
            we were actually used for an inbound or outbound call. */
         if (ast->_state != AST_STATE_RESERVED) {
            time(&p->guardtime);
            p->guardtime += 2;
         }
         break;
      default:
         tone_zone_play_tone(p->subs[SUB_REAL].dfd, -1);
      }
      if (p->cidspill)
         ast_free(p->cidspill);
      if (p->sig)
         dahdi_disable_ec(p);
      x = 0;
      ast_channel_setoption(ast,AST_OPTION_TONE_VERIFY,&x,sizeof(char),0);
      ast_channel_setoption(ast,AST_OPTION_TDD,&x,sizeof(char),0);
      p->didtdd = 0;
      p->cidspill = NULL;
      p->callwaitcas = 0;
      p->callwaiting = p->permcallwaiting;
      p->hidecallerid = p->permhidecallerid;
      p->dialing = 0;
      p->rdnis[0] = '\0';
      update_conf(p);
      reset_conf(p);
      /* Restore data mode */
      if ((p->sig == SIG_PRI) || (p->sig == SIG_SS7) || (p->sig == SIG_BRI) || (p->sig == SIG_BRI_PTMP)) {
         x = 0;
         ast_channel_setoption(ast,AST_OPTION_AUDIO_MODE,&x,sizeof(char),0);
      }
#ifdef HAVE_PRI
      if (p->bearer) {
         ast_debug(1, "Freeing up bearer channel %d\n", p->bearer->channel);
         /* Free up the bearer channel as well, and
            don't use its file descriptor anymore */
         update_conf(p->bearer);
         reset_conf(p->bearer);
         p->bearer->owner = NULL;
         p->bearer->realcall = NULL;
         p->bearer = NULL;
         p->subs[SUB_REAL].dfd = -1;
         p->pri = NULL;
      }
#endif
      if (num_restart_pending == 0)
         restart_monitor();
   }

   p->callwaitingrepeat = 0;
   p->cidcwexpire = 0;
   p->oprmode = 0;
   ast->tech_pvt = NULL;
   ast_mutex_unlock(&p->lock);
   ast_module_unref(ast_module_info->self);
   ast_verb(3, "Hungup '%s'\n", ast->name);

   ast_mutex_lock(&iflock);

   if (p->restartpending) {
      num_restart_pending--;
   }

   tmp = iflist;
   prev = NULL;
   if (p->destroy) {
      while (tmp) {
         if (tmp == p) {
            destroy_channel(prev, tmp, 0);
            break;
         } else {
            prev = tmp;
            tmp = tmp->next;
         }
      }
   }
   ast_mutex_unlock(&iflock);
   return 0;
}

static int dahdi_answer(struct ast_channel *ast)
{
   struct dahdi_pvt *p = ast->tech_pvt;
   int res = 0;
   int index;
   int oldstate = ast->_state;
   ast_setstate(ast, AST_STATE_UP);
   ast_mutex_lock(&p->lock);
   index = dahdi_get_index(ast, p, 0);
   if (index < 0)
      index = SUB_REAL;
   /* nothing to do if a radio channel */
   if ((p->radio || (p->oprmode < 0))) {
      ast_mutex_unlock(&p->lock);
      return 0;
   }
   switch (p->sig) {
   case SIG_FXSLS:
   case SIG_FXSGS:
   case SIG_FXSKS:
      p->ringt = 0;
      /* Fall through */
   case SIG_EM:
   case SIG_EM_E1:
   case SIG_EMWINK:
   case SIG_FEATD:
   case SIG_FEATDMF:
   case SIG_FEATDMF_TA:
   case SIG_E911:
   case SIG_FGC_CAMA:
   case SIG_FGC_CAMAMF:
   case SIG_FEATB:
   case SIG_SF:
   case SIG_SFWINK:
   case SIG_SF_FEATD:
   case SIG_SF_FEATDMF:
   case SIG_SF_FEATB:
   case SIG_FXOLS:
   case SIG_FXOGS:
   case SIG_FXOKS:
      /* Pick up the line */
      ast_debug(1, "Took %s off hook\n", ast->name);
      if (p->hanguponpolarityswitch) {
         p->polaritydelaytv = ast_tvnow();
      }
      res = dahdi_set_hook(p->subs[SUB_REAL].dfd, DAHDI_OFFHOOK);
      tone_zone_play_tone(p->subs[index].dfd, -1);
      p->dialing = 0;
      if ((index == SUB_REAL) && p->subs[SUB_THREEWAY].inthreeway) {
         if (oldstate == AST_STATE_RINGING) {
            ast_debug(1, "Finally swapping real and threeway\n");
            tone_zone_play_tone(p->subs[SUB_THREEWAY].dfd, -1);
            swap_subs(p, SUB_THREEWAY, SUB_REAL);
            p->owner = p->subs[SUB_REAL].owner;
         }
      }
      if (p->sig & __DAHDI_SIG_FXS) {
         dahdi_enable_ec(p);
         dahdi_train_ec(p);
      }
      break;
#ifdef HAVE_PRI
   case SIG_BRI:
   case SIG_BRI_PTMP:
   case SIG_PRI:
      /* Send a pri acknowledge */
      if (!pri_grab(p, p->pri)) {
         p->proceeding = 1;
         p->dialing = 0;
         res = pri_answer(p->pri->pri, p->call, 0, !p->digital);
         pri_rel(p->pri);
      } else {
         ast_log(LOG_WARNING, "Unable to grab PRI on span %d\n", p->span);
         res = -1;
      }
      break;
#endif
#ifdef HAVE_SS7
   case SIG_SS7:
      if (!ss7_grab(p, p->ss7)) {
         p->proceeding = 1;
         res = isup_anm(p->ss7->ss7, p->ss7call);
         ss7_rel(p->ss7);
      } else {
         ast_log(LOG_WARNING, "Unable to grab SS7 on span %d\n", p->span);
         res = -1;
      }
      break;
#endif
   case 0:
      ast_mutex_unlock(&p->lock);
      return 0;
   default:
      ast_log(LOG_WARNING, "Don't know how to answer signalling %d (channel %d)\n", p->sig, p->channel);
      res = -1;
   }
   ast_mutex_unlock(&p->lock);
   return res;
}

static int dahdi_setoption(struct ast_channel *chan, int option, void *data, int datalen)
{
   char *cp;
   signed char *scp;
   int x;
   int index;
   struct dahdi_pvt *p = chan->tech_pvt, *pp;
   struct oprmode *oprmode;
   

   /* all supported options require data */
   if (!data || (datalen < 1)) {
      errno = EINVAL;
      return -1;
   }

   switch (option) {
   case AST_OPTION_TXGAIN:
      scp = (signed char *) data;
      index = dahdi_get_index(chan, p, 0);
      if (index < 0) {
         ast_log(LOG_WARNING, "No index in TXGAIN?\n");
         return -1;
      }
      ast_debug(1, "Setting actual tx gain on %s to %f\n", chan->name, p->txgain + (float) *scp);
      return set_actual_txgain(p->subs[index].dfd, 0, p->txgain + (float) *scp, p->law);
   case AST_OPTION_RXGAIN:
      scp = (signed char *) data;
      index = dahdi_get_index(chan, p, 0);
      if (index < 0) {
         ast_log(LOG_WARNING, "No index in RXGAIN?\n");
         return -1;
      }
      ast_debug(1, "Setting actual rx gain on %s to %f\n", chan->name, p->rxgain + (float) *scp);
      return set_actual_rxgain(p->subs[index].dfd, 0, p->rxgain + (float) *scp, p->law);
   case AST_OPTION_TONE_VERIFY:
      if (!p->dsp)
         break;
      cp = (char *) data;
      switch (*cp) {
      case 1:
         ast_debug(1, "Set option TONE VERIFY, mode: MUTECONF(1) on %s\n",chan->name);
         ast_dsp_digitmode(p->dsp, DSP_DIGITMODE_MUTECONF | p->dtmfrelax);  /* set mute mode if desired */
         break;
      case 2:
         ast_debug(1, "Set option TONE VERIFY, mode: MUTECONF/MAX(2) on %s\n",chan->name);
         ast_dsp_digitmode(p->dsp, DSP_DIGITMODE_MUTECONF | DSP_DIGITMODE_MUTEMAX | p->dtmfrelax);  /* set mute mode if desired */
         break;
      default:
         ast_debug(1, "Set option TONE VERIFY, mode: OFF(0) on %s\n",chan->name);
         ast_dsp_digitmode(p->dsp, DSP_DIGITMODE_DTMF | p->dtmfrelax);  /* set mute mode if desired */
         break;
      }
      break;
   case AST_OPTION_TDD:
      /* turn on or off TDD */
      cp = (char *) data;
      p->mate = 0;
      if (!*cp) { /* turn it off */
         ast_debug(1, "Set option TDD MODE, value: OFF(0) on %s\n",chan->name);
         if (p->tdd)
            tdd_free(p->tdd);
         p->tdd = 0;
         break;
      }
      ast_debug(1, "Set option TDD MODE, value: %s(%d) on %s\n",
         (*cp == 2) ? "MATE" : "ON", (int) *cp, chan->name);
      dahdi_disable_ec(p);
      /* otherwise, turn it on */
      if (!p->didtdd) { /* if havent done it yet */
         unsigned char mybuf[41000];/*! \todo XXX This is an abuse of the stack!! */
         unsigned char *buf;
         int size, res, fd, len;
         struct pollfd fds[1];

         buf = mybuf;
         memset(buf, 0x7f, sizeof(mybuf)); /* set to silence */
         ast_tdd_gen_ecdisa(buf + 16000, 16000);  /* put in tone */
         len = 40000;
         index = dahdi_get_index(chan, p, 0);
         if (index < 0) {
            ast_log(LOG_WARNING, "No index in TDD?\n");
            return -1;
         }
         fd = p->subs[index].dfd;
         while (len) {
            if (ast_check_hangup(chan))
               return -1;
            size = len;
            if (size > READ_SIZE)
               size = READ_SIZE;
            fds[0].fd = fd;
            fds[0].events = POLLPRI | POLLOUT;
            fds[0].revents = 0;
            res = poll(fds, 1, -1);
            if (!res) {
               ast_debug(1, "poll (for write) ret. 0 on channel %d\n", p->channel);
               continue;
            }
            /* if got exception */
            if (fds[0].revents & POLLPRI)
               return -1;
            if (!(fds[0].revents & POLLOUT)) {
               ast_debug(1, "write fd not ready on channel %d\n", p->channel);
               continue;
            }
            res = write(fd, buf, size);
            if (res != size) {
               if (res == -1) return -1;
               ast_debug(1, "Write returned %d (%s) on channel %d\n", res, strerror(errno), p->channel);
               break;
            }
            len -= size;
            buf += size;
         }
         p->didtdd = 1; /* set to have done it now */    
      }
      if (*cp == 2) { /* Mate mode */
         if (p->tdd)
            tdd_free(p->tdd);
         p->tdd = 0;
         p->mate = 1;
         break;
      }     
      if (!p->tdd) { /* if we dont have one yet */
         p->tdd = tdd_new(); /* allocate one */
      }     
      break;
   case AST_OPTION_RELAXDTMF:  /* Relax DTMF decoding (or not) */
      if (!p->dsp)
         break;
      cp = (char *) data;
      ast_debug(1, "Set option RELAX DTMF, value: %s(%d) on %s\n",
         *cp ? "ON" : "OFF", (int) *cp, chan->name);
      ast_dsp_digitmode(p->dsp, ((*cp) ? DSP_DIGITMODE_RELAXDTMF : DSP_DIGITMODE_DTMF) | p->dtmfrelax);
      break;
   case AST_OPTION_AUDIO_MODE:  /* Set AUDIO mode (or not) */
      cp = (char *) data;
      if (!*cp) {    
         ast_debug(1, "Set option AUDIO MODE, value: OFF(0) on %s\n", chan->name);
         x = 0;
         dahdi_disable_ec(p);
      } else {    
         ast_debug(1, "Set option AUDIO MODE, value: ON(1) on %s\n", chan->name);
         x = 1;
      }
      if (ioctl(p->subs[SUB_REAL].dfd, DAHDI_AUDIOMODE, &x) == -1)
         ast_log(LOG_WARNING, "Unable to set audio mode on channel %d to %d: %s\n", p->channel, x, strerror(errno));
      break;
   case AST_OPTION_OPRMODE:  /* Operator services mode */
      oprmode = (struct oprmode *) data;
      pp = oprmode->peer->tech_pvt;
      p->oprmode = pp->oprmode = 0;
      /* setup peers */
      p->oprpeer = pp;
      pp->oprpeer = p;
      /* setup modes, if any */
      if (oprmode->mode) 
      {
         pp->oprmode = oprmode->mode;
         p->oprmode = -oprmode->mode;
      }
      ast_debug(1, "Set Operator Services mode, value: %d on %s/%s\n",
         oprmode->mode, chan->name,oprmode->peer->name);
      break;
   case AST_OPTION_ECHOCAN:
      cp = (char *) data;
      if (*cp) {
         ast_debug(1, "Enabling echo cancelation on %s\n", chan->name);
         dahdi_enable_ec(p);
      } else {
         ast_debug(1, "Disabling echo cancelation on %s\n", chan->name);
         dahdi_disable_ec(p);
      }
      break;
   }
   errno = 0;

   return 0;
}

static int dahdi_func_read(struct ast_channel *chan, const char *function, char *data, char *buf, size_t len)
{
   struct dahdi_pvt *p = chan->tech_pvt;
   
   if (!strcasecmp(data, "rxgain")) {
      ast_mutex_lock(&p->lock);
      snprintf(buf, len, "%f", p->rxgain);
      ast_mutex_unlock(&p->lock);   
   } else if (!strcasecmp(data, "txgain")) {
      ast_mutex_lock(&p->lock);
      snprintf(buf, len, "%f", p->txgain);
      ast_mutex_unlock(&p->lock);   
   } else {
      ast_copy_string(buf, "", len);
   }
   return 0;
}


static void dahdi_unlink(struct dahdi_pvt *slave, struct dahdi_pvt *master, int needlock)
{
   /* Unlink a specific slave or all slaves/masters from a given master */
   int x;
   int hasslaves;
   if (!master)
      return;
   if (needlock) {
      ast_mutex_lock(&master->lock);
      if (slave) {
         while (ast_mutex_trylock(&slave->lock)) {
            DEADLOCK_AVOIDANCE(&master->lock);
         }
      }
   }
   hasslaves = 0;
   for (x = 0; x < MAX_SLAVES; x++) {
      if (master->slaves[x]) {
         if (!slave || (master->slaves[x] == slave)) {
            /* Take slave out of the conference */
            ast_debug(1, "Unlinking slave %d from %d\n", master->slaves[x]->channel, master->channel);
            conf_del(master, &master->slaves[x]->subs[SUB_REAL], SUB_REAL);
            conf_del(master->slaves[x], &master->subs[SUB_REAL], SUB_REAL);
            master->slaves[x]->master = NULL;
            master->slaves[x] = NULL;
         } else
            hasslaves = 1;
      }
      if (!hasslaves)
         master->inconference = 0;
   }
   if (!slave) {
      if (master->master) {
         /* Take master out of the conference */
         conf_del(master->master, &master->subs[SUB_REAL], SUB_REAL);
         conf_del(master, &master->master->subs[SUB_REAL], SUB_REAL);
         hasslaves = 0;
         for (x = 0; x < MAX_SLAVES; x++) {
            if (master->master->slaves[x] == master)
               master->master->slaves[x] = NULL;
            else if (master->master->slaves[x])
               hasslaves = 1;
         }
         if (!hasslaves)
            master->master->inconference = 0;
      }
      master->master = NULL;
   }
   update_conf(master);
   if (needlock) {
      if (slave)
         ast_mutex_unlock(&slave->lock);
      ast_mutex_unlock(&master->lock);
   }
}

static void dahdi_link(struct dahdi_pvt *slave, struct dahdi_pvt *master) {
   int x;
   if (!slave || !master) {
      ast_log(LOG_WARNING, "Tried to link to/from NULL??\n");
      return;
   }
   for (x = 0; x < MAX_SLAVES; x++) {
      if (!master->slaves[x]) {
         master->slaves[x] = slave;
         break;
      }
   }
   if (x >= MAX_SLAVES) {
      ast_log(LOG_WARNING, "Replacing slave %d with new slave, %d\n", master->slaves[MAX_SLAVES - 1]->channel, slave->channel);
      master->slaves[MAX_SLAVES - 1] = slave;
   }
   if (slave->master) 
      ast_log(LOG_WARNING, "Replacing master %d with new master, %d\n", slave->master->channel, master->channel);
   slave->master = master;
   
   ast_debug(1, "Making %d slave to master %d at %d\n", slave->channel, master->channel, x);
}

static void disable_dtmf_detect(struct dahdi_pvt *p)
{
   int val;

   p->ignoredtmf = 1;

   val = 0;
   ioctl(p->subs[SUB_REAL].dfd, DAHDI_TONEDETECT, &val);

   if (!p->hardwaredtmf && p->dsp) {
      p->dsp_features &= ~DSP_FEATURE_DTMF_DETECT;
      ast_dsp_set_features(p->dsp, p->dsp_features);
   }
}

static void enable_dtmf_detect(struct dahdi_pvt *p)
{
   int val;

   if (p->channel == CHAN_PSEUDO)
      return;

   p->ignoredtmf = 0;

   val = DAHDI_TONEDETECT_ON | DAHDI_TONEDETECT_MUTE;
   ioctl(p->subs[SUB_REAL].dfd, DAHDI_TONEDETECT, &val);

   if (!p->hardwaredtmf && p->dsp) {
      p->dsp_features |= DSP_FEATURE_DTMF_DETECT;
      ast_dsp_set_features(p->dsp, p->dsp_features);
   }
}

static enum ast_bridge_result dahdi_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc, int timeoutms)
{
   struct ast_channel *who;
   struct dahdi_pvt *p0, *p1, *op0, *op1;
   struct dahdi_pvt *master = NULL, *slave = NULL;
   struct ast_frame *f;
   int inconf = 0;
   int nothingok = 1;
   int ofd0, ofd1;
   int oi0, oi1, i0 = -1, i1 = -1, t0, t1;
   int os0 = -1, os1 = -1;
   int priority = 0;
   struct ast_channel *oc0, *oc1;
   enum ast_bridge_result res;

#ifdef PRI_2BCT
   int triedtopribridge = 0;
   q931_call *q931c0 = NULL, *q931c1 = NULL;
#endif

   /* For now, don't attempt to native bridge if either channel needs DTMF detection.
      There is code below to handle it properly until DTMF is actually seen,
      but due to currently unresolved issues it's ignored...
   */

   if (flags & (AST_BRIDGE_DTMF_CHANNEL_0 | AST_BRIDGE_DTMF_CHANNEL_1))
      return AST_BRIDGE_FAILED_NOWARN;

   ast_channel_lock(c0);
   while (ast_channel_trylock(c1)) {
      ast_channel_unlock(c0);
      usleep(1);
      ast_channel_lock(c0);
   }

   p0 = c0->tech_pvt;
   p1 = c1->tech_pvt;
   /* cant do pseudo-channels here */
   if (!p0 || (!p0->sig) || !p1 || (!p1->sig)) {
      ast_channel_unlock(c0);
      ast_channel_unlock(c1);
      return AST_BRIDGE_FAILED_NOWARN;
   }

   oi0 = dahdi_get_index(c0, p0, 0);
   oi1 = dahdi_get_index(c1, p1, 0);
   if ((oi0 < 0) || (oi1 < 0)) {
      ast_channel_unlock(c0);
      ast_channel_unlock(c1);
      return AST_BRIDGE_FAILED;
   }

   op0 = p0 = c0->tech_pvt;
   op1 = p1 = c1->tech_pvt;
   ofd0 = c0->fds[0];
   ofd1 = c1->fds[0];
   oc0 = p0->owner;
   oc1 = p1->owner;

   if (ast_mutex_trylock(&p0->lock)) {
      /* Don't block, due to potential for deadlock */
      ast_channel_unlock(c0);
      ast_channel_unlock(c1);
      ast_log(LOG_NOTICE, "Avoiding deadlock...\n");
      return AST_BRIDGE_RETRY;
   }
   if (ast_mutex_trylock(&p1->lock)) {
      /* Don't block, due to potential for deadlock */
      ast_mutex_unlock(&p0->lock);
      ast_channel_unlock(c0);
      ast_channel_unlock(c1);
      ast_log(LOG_NOTICE, "Avoiding deadlock...\n");
      return AST_BRIDGE_RETRY;
   }

   if ((oi0 == SUB_REAL) && (oi1 == SUB_REAL)) {
      if (p0->owner && p1->owner) {
         /* If we don't have a call-wait in a 3-way, and we aren't in a 3-way, we can be master */
         if (!p0->subs[SUB_CALLWAIT].inthreeway && !p1->subs[SUB_REAL].inthreeway) {
            master = p0;
            slave = p1;
            inconf = 1;
         } else if (!p1->subs[SUB_CALLWAIT].inthreeway && !p0->subs[SUB_REAL].inthreeway) {
            master = p1;
            slave = p0;
            inconf = 1;
         } else {
            ast_log(LOG_WARNING, "Huh?  Both calls are callwaits or 3-ways?  That's clever...?\n");
            ast_log(LOG_WARNING, "p0: chan %d/%d/CW%d/3W%d, p1: chan %d/%d/CW%d/3W%d\n",
               p0->channel,
               oi0, (p0->subs[SUB_CALLWAIT].dfd > -1) ? 1 : 0,
               p0->subs[SUB_REAL].inthreeway, p0->channel,
               oi0, (p1->subs[SUB_CALLWAIT].dfd > -1) ? 1 : 0,
               p1->subs[SUB_REAL].inthreeway);
         }
         nothingok = 0;
      }
   } else if ((oi0 == SUB_REAL) && (oi1 == SUB_THREEWAY)) {
      if (p1->subs[SUB_THREEWAY].inthreeway) {
         master = p1;
         slave = p0;
         nothingok = 0;
      }
   } else if ((oi0 == SUB_THREEWAY) && (oi1 == SUB_REAL)) {
      if (p0->subs[SUB_THREEWAY].inthreeway) {
         master = p0;
         slave = p1;
         nothingok = 0;
      }
   } else if ((oi0 == SUB_REAL) && (oi1 == SUB_CALLWAIT)) {
      /* We have a real and a call wait.  If we're in a three way call, put us in it, otherwise, 
         don't put us in anything */
      if (p1->subs[SUB_CALLWAIT].inthreeway) {
         master = p1;
         slave = p0;
         nothingok = 0;
      }
   } else if ((oi0 == SUB_CALLWAIT) && (oi1 == SUB_REAL)) {
      /* Same as previous */
      if (p0->subs[SUB_CALLWAIT].inthreeway) {
         master = p0;
         slave = p1;
         nothingok = 0;
      }
   }
   ast_debug(1, "master: %d, slave: %d, nothingok: %d\n",
      master ? master->channel : 0, slave ? slave->channel : 0, nothingok);
   if (master && slave) {
      /* Stop any tones, or play ringtone as appropriate.  If they're bridged
         in an active threeway call with a channel that is ringing, we should
         indicate ringing. */
      if ((oi1 == SUB_THREEWAY) && 
          p1->subs[SUB_THREEWAY].inthreeway && 
          p1->subs[SUB_REAL].owner && 
          p1->subs[SUB_REAL].inthreeway && 
          (p1->subs[SUB_REAL].owner->_state == AST_STATE_RINGING)) {
         ast_debug(1, "Playing ringback on %s since %s is in a ringing three-way\n", c0->name, c1->name);
         tone_zone_play_tone(p0->subs[oi0].dfd, DAHDI_TONE_RINGTONE);
         os1 = p1->subs[SUB_REAL].owner->_state;
      } else {
         ast_debug(1, "Stopping tones on %d/%d talking to %d/%d\n", p0->channel, oi0, p1->channel, oi1);
         tone_zone_play_tone(p0->subs[oi0].dfd, -1);
      }
      if ((oi0 == SUB_THREEWAY) && 
          p0->subs[SUB_THREEWAY].inthreeway && 
          p0->subs[SUB_REAL].owner && 
          p0->subs[SUB_REAL].inthreeway && 
          (p0->subs[SUB_REAL].owner->_state == AST_STATE_RINGING)) {
         ast_debug(1, "Playing ringback on %s since %s is in a ringing three-way\n", c1->name, c0->name);
         tone_zone_play_tone(p1->subs[oi1].dfd, DAHDI_TONE_RINGTONE);
         os0 = p0->subs[SUB_REAL].owner->_state;
      } else {
         ast_debug(1, "Stopping tones on %d/%d talking to %d/%d\n", p1->channel, oi1, p0->channel, oi0);
         tone_zone_play_tone(p1->subs[oi0].dfd, -1);
      }
      if ((oi0 == SUB_REAL) && (oi1 == SUB_REAL)) {
         if (!p0->echocanbridged || !p1->echocanbridged) {
            /* Disable echo cancellation if appropriate */
            dahdi_disable_ec(p0);
            dahdi_disable_ec(p1);
         }
      }
      dahdi_link(slave, master);
      master->inconference = inconf;
   } else if (!nothingok)
      ast_log(LOG_WARNING, "Can't link %d/%s with %d/%s\n", p0->channel, subnames[oi0], p1->channel, subnames[oi1]);

   update_conf(p0);
   update_conf(p1);
   t0 = p0->subs[SUB_REAL].inthreeway;
   t1 = p1->subs[SUB_REAL].inthreeway;

   ast_mutex_unlock(&p0->lock);
   ast_mutex_unlock(&p1->lock);

   ast_channel_unlock(c0);
   ast_channel_unlock(c1);

   /* Native bridge failed */
   if ((!master || !slave) && !nothingok) {
      dahdi_enable_ec(p0);
      dahdi_enable_ec(p1);
      return AST_BRIDGE_FAILED;
   }
   
   ast_verb(3, "Native bridging %s and %s\n", c0->name, c1->name);

   if (!(flags & AST_BRIDGE_DTMF_CHANNEL_0) && (oi0 == SUB_REAL))
      disable_dtmf_detect(op0);

   if (!(flags & AST_BRIDGE_DTMF_CHANNEL_1) && (oi1 == SUB_REAL))
      disable_dtmf_detect(op1);

   for (;;) {
      struct ast_channel *c0_priority[2] = {c0, c1};
      struct ast_channel *c1_priority[2] = {c1, c0};

      /* Here's our main loop...  Start by locking things, looking for private parts, 
         and then balking if anything is wrong */
      
      ast_channel_lock(c0);
      while (ast_channel_trylock(c1)) {
         ast_channel_unlock(c0);
         usleep(1);
         ast_channel_lock(c0);
      }

      p0 = c0->tech_pvt;
      p1 = c1->tech_pvt;

      if (op0 == p0)
         i0 = dahdi_get_index(c0, p0, 1);
      if (op1 == p1)
         i1 = dahdi_get_index(c1, p1, 1);

      ast_channel_unlock(c0);
      ast_channel_unlock(c1);

      if (!timeoutms || 
          (op0 != p0) ||
          (op1 != p1) || 
          (ofd0 != c0->fds[0]) || 
          (ofd1 != c1->fds[0]) ||
          (p0->subs[SUB_REAL].owner && (os0 > -1) && (os0 != p0->subs[SUB_REAL].owner->_state)) || 
          (p1->subs[SUB_REAL].owner && (os1 > -1) && (os1 != p1->subs[SUB_REAL].owner->_state)) || 
          (oc0 != p0->owner) || 
          (oc1 != p1->owner) ||
          (t0 != p0->subs[SUB_REAL].inthreeway) ||
          (t1 != p1->subs[SUB_REAL].inthreeway) ||
          (oi0 != i0) ||
          (oi1 != i1)) {
         ast_debug(1, "Something changed out on %d/%d to %d/%d, returning -3 to restart\n",
            op0->channel, oi0, op1->channel, oi1);
         res = AST_BRIDGE_RETRY;
         goto return_from_bridge;
      }

#ifdef PRI_2BCT
      q931c0 = p0->call;
      q931c1 = p1->call;
      if (p0->transfer && p1->transfer 
          && q931c0 && q931c1 
          && !triedtopribridge) {
         pri_channel_bridge(q931c0, q931c1);
         triedtopribridge = 1;
      }
#endif

      who = ast_waitfor_n(priority ? c0_priority : c1_priority, 2, &timeoutms);
      if (!who) {
         ast_debug(1, "Ooh, empty read...\n");
         continue;
      }
      f = ast_read(who);
      if (!f || (f->frametype == AST_FRAME_CONTROL)) {
         *fo = f;
         *rc = who;
         res = AST_BRIDGE_COMPLETE;
         goto return_from_bridge;
      }
      if (f->frametype == AST_FRAME_DTMF) {
         if ((who == c0) && p0->pulsedial) {
            ast_write(c1, f);
         } else if ((who == c1) && p1->pulsedial) {
            ast_write(c0, f);
         } else {
            *fo = f;
            *rc = who;
            res = AST_BRIDGE_COMPLETE;
            goto return_from_bridge;
         }
      }
      ast_frfree(f);
      
      /* Swap who gets priority */
      priority = !priority;
   }

return_from_bridge:
   if (op0 == p0)
      dahdi_enable_ec(p0);

   if (op1 == p1)
      dahdi_enable_ec(p1);

   if (!(flags & AST_BRIDGE_DTMF_CHANNEL_0) && (oi0 == SUB_REAL))
      enable_dtmf_detect(op0);

   if (!(flags & AST_BRIDGE_DTMF_CHANNEL_1) && (oi1 == SUB_REAL))
      enable_dtmf_detect(op1);

   dahdi_unlink(slave, master, 1);

   return res;
}

static int dahdi_fixup(struct ast_channel *oldchan, struct ast_channel *newchan)
{
   struct dahdi_pvt *p = newchan->tech_pvt;
   int x;
   ast_mutex_lock(&p->lock);
   ast_debug(1, "New owner for channel %d is %s\n", p->channel, newchan->name);
   if (p->owner == oldchan) {
      p->owner = newchan;
   }
   for (x = 0; x < 3; x++)
      if (p->subs[x].owner == oldchan) {
         if (!x)
            dahdi_unlink(NULL, p, 0);
         p->subs[x].owner = newchan;
      }
   if (newchan->_state == AST_STATE_RINGING) 
      dahdi_indicate(newchan, AST_CONTROL_RINGING, NULL, 0);
   update_conf(p);
   ast_mutex_unlock(&p->lock);
   return 0;
}

static int dahdi_ring_phone(struct dahdi_pvt *p)
{
   int x;
   int res;
   /* Make sure our transmit state is on hook */
   x = 0;
   x = DAHDI_ONHOOK;
   res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_HOOK, &x);
   do {
      x = DAHDI_RING;
      res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_HOOK, &x);
      if (res) {
         switch (errno) {
         case EBUSY:
         case EINTR:
            /* Wait just in case */
            usleep(10000);
            continue;
         case EINPROGRESS:
            res = 0;
            break;
         default:
            ast_log(LOG_WARNING, "Couldn't ring the phone: %s\n", strerror(errno));
            res = 0;
         }
      }
   } while (res);
   return res;
}

static void *ss_thread(void *data);

static struct ast_channel *dahdi_new(struct dahdi_pvt *, int, int, int, int, int);

static int attempt_transfer(struct dahdi_pvt *p)
{
   /* In order to transfer, we need at least one of the channels to
      actually be in a call bridge.  We can't conference two applications
      together (but then, why would we want to?) */
   if (ast_bridged_channel(p->subs[SUB_REAL].owner)) {
      /* The three-way person we're about to transfer to could still be in MOH, so
         stop if now if appropriate */
      if (ast_bridged_channel(p->subs[SUB_THREEWAY].owner))
         ast_queue_control(p->subs[SUB_THREEWAY].owner, AST_CONTROL_UNHOLD);
      if (p->subs[SUB_REAL].owner->_state == AST_STATE_RINGING) {
         ast_indicate(ast_bridged_channel(p->subs[SUB_REAL].owner), AST_CONTROL_RINGING);
      }
      if (p->subs[SUB_THREEWAY].owner->_state == AST_STATE_RING) {
         tone_zone_play_tone(p->subs[SUB_THREEWAY].dfd, DAHDI_TONE_RINGTONE);
      }
       if (ast_channel_masquerade(p->subs[SUB_THREEWAY].owner, ast_bridged_channel(p->subs[SUB_REAL].owner))) {
         ast_log(LOG_WARNING, "Unable to masquerade %s as %s\n",
               ast_bridged_channel(p->subs[SUB_REAL].owner)->name, p->subs[SUB_THREEWAY].owner->name);
         return -1;
      }
      /* Orphan the channel after releasing the lock */
      ast_channel_unlock(p->subs[SUB_THREEWAY].owner);
      unalloc_sub(p, SUB_THREEWAY);
   } else if (ast_bridged_channel(p->subs[SUB_THREEWAY].owner)) {
      ast_queue_control(p->subs[SUB_REAL].owner, AST_CONTROL_UNHOLD);
      if (p->subs[SUB_THREEWAY].owner->_state == AST_STATE_RINGING) {
         ast_indicate(ast_bridged_channel(p->subs[SUB_THREEWAY].owner), AST_CONTROL_RINGING);
      }
      if (p->subs[SUB_REAL].owner->_state == AST_STATE_RING) {
         tone_zone_play_tone(p->subs[SUB_REAL].dfd, DAHDI_TONE_RINGTONE);
      }
      if (ast_channel_masquerade(p->subs[SUB_REAL].owner, ast_bridged_channel(p->subs[SUB_THREEWAY].owner))) {
         ast_log(LOG_WARNING, "Unable to masquerade %s as %s\n",
               ast_bridged_channel(p->subs[SUB_THREEWAY].owner)->name, p->subs[SUB_REAL].owner->name);
         return -1;
      }
      /* Three-way is now the REAL */
      swap_subs(p, SUB_THREEWAY, SUB_REAL);
      ast_channel_unlock(p->subs[SUB_REAL].owner);
      unalloc_sub(p, SUB_THREEWAY);
      /* Tell the caller not to hangup */
      return 1;
   } else {
      ast_debug(1, "Neither %s nor %s are in a bridge, nothing to transfer\n",
         p->subs[SUB_REAL].owner->name, p->subs[SUB_THREEWAY].owner->name);
      p->subs[SUB_THREEWAY].owner->_softhangup |= AST_SOFTHANGUP_DEV;
      return -1;
   }
   return 0;
}

static int check_for_conference(struct dahdi_pvt *p)
{
   struct dahdi_confinfo ci;
   /* Fine if we already have a master, etc */
   if (p->master || (p->confno > -1))
      return 0;
   memset(&ci, 0, sizeof(ci));
   if (ioctl(p->subs[SUB_REAL].dfd, DAHDI_GETCONF, &ci)) {
      ast_log(LOG_WARNING, "Failed to get conference info on channel %d: %s\n", p->channel, strerror(errno));
      return 0;
   }
   /* If we have no master and don't have a confno, then 
      if we're in a conference, it's probably a MeetMe room or
      some such, so don't let us 3-way out! */
   if ((p->subs[SUB_REAL].curconf.confno != ci.confno) || (p->subs[SUB_REAL].curconf.confmode != ci.confmode)) {
      ast_verb(3, "Avoiding 3-way call when in an external conference\n");
      return 1;
   }
   return 0;
}

/*! Checks channel for alarms
 * \param p a channel to check for alarms.
 * \returns the alarms on the span to which the channel belongs, or alarms on
 *          the channel if no span alarms.
 */
static int get_alarms(struct dahdi_pvt *p)
{
   int res;
   struct dahdi_spaninfo zi;
   struct dahdi_params params;

   memset(&zi, 0, sizeof(zi));
   zi.spanno = p->span;

   if ((res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_SPANSTAT, &zi)) >= 0) {
      if (zi.alarms != DAHDI_ALARM_NONE)
         return zi.alarms;
   } else {
      ast_log(LOG_WARNING, "Unable to determine alarm on channel %d: %s\n", p->channel, strerror(errno));
      return 0;
   }

   /* No alarms on the span. Check for channel alarms. */
   memset(&params, 0, sizeof(params));
   if ((res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_GET_PARAMS, &params)) >= 0)
      return params.chan_alarms;

   ast_log(LOG_WARNING, "Unable to determine alarm on channel %d\n", p->channel);

   return DAHDI_ALARM_NONE;
}

static void dahdi_handle_dtmfup(struct ast_channel *ast, int index, struct ast_frame **dest)
{
   struct dahdi_pvt *p = ast->tech_pvt;
   struct ast_frame *f = *dest;

   ast_debug(1, "DTMF digit: %c on %s\n", f->subclass, ast->name);

   if (p->confirmanswer) {
      ast_debug(1, "Confirm answer on %s!\n", ast->name);
      /* Upon receiving a DTMF digit, consider this an answer confirmation instead
         of a DTMF digit */
      p->subs[index].f.frametype = AST_FRAME_CONTROL;
      p->subs[index].f.subclass = AST_CONTROL_ANSWER;
      *dest = &p->subs[index].f;
      /* Reset confirmanswer so DTMF's will behave properly for the duration of the call */
      p->confirmanswer = 0;
   } else if (p->callwaitcas) {
      if ((f->subclass == 'A') || (f->subclass == 'D')) {
         ast_debug(1, "Got some DTMF, but it's for the CAS\n");
         if (p->cidspill)
            ast_free(p->cidspill);
         send_cwcidspill(p);
      }
      if ((f->subclass != 'm') && (f->subclass != 'u')) 
         p->callwaitcas = 0;
      p->subs[index].f.frametype = AST_FRAME_NULL;
      p->subs[index].f.subclass = 0;
      *dest = &p->subs[index].f;
   } else if (f->subclass == 'f') {
      /* Fax tone -- Handle and return NULL */
      if ((p->callprogress & CALLPROGRESS_FAX) && !p->faxhandled) {
         p->faxhandled = 1;
         if (strcmp(ast->exten, "fax")) {
            const char *target_context = S_OR(ast->macrocontext, ast->context);

            /* We need to unlock 'ast' here because ast_exists_extension has the
             * potential to start autoservice on the channel. Such action is prone
             * to deadlock.
             */
            ast_mutex_unlock(&p->lock);
            ast_channel_unlock(ast);
            if (ast_exists_extension(ast, target_context, "fax", 1, ast->cid.cid_num)) {
               ast_channel_lock(ast);
               ast_mutex_lock(&p->lock);
               ast_verb(3, "Redirecting %s to fax extension\n", ast->name);
               /* Save the DID/DNIS when we transfer the fax call to a "fax" extension */
               pbx_builtin_setvar_helper(ast, "FAXEXTEN", ast->exten);
               if (ast_async_goto(ast, target_context, "fax", 1))
                  ast_log(LOG_WARNING, "Failed to async goto '%s' into fax of '%s'\n", ast->name, target_context);
            } else {
               ast_channel_lock(ast);
               ast_mutex_lock(&p->lock);
               ast_log(LOG_NOTICE, "Fax detected, but no fax extension\n");
            }
         } else {
            ast_debug(1, "Already in a fax extension, not redirecting\n");
         }
      } else {
         ast_debug(1, "Fax already handled\n");
      }
      dahdi_confmute(p, 0);
      p->subs[index].f.frametype = AST_FRAME_NULL;
      p->subs[index].f.subclass = 0;
      *dest = &p->subs[index].f;
   } else if (f->subclass == 'm') {
      /* Confmute request */
      dahdi_confmute(p, 1);
      p->subs[index].f.frametype = AST_FRAME_NULL;
      p->subs[index].f.subclass = 0;
      *dest = &p->subs[index].f;    
   } else if (f->subclass == 'u') {
      /* Unmute */
      dahdi_confmute(p, 0);
      p->subs[index].f.frametype = AST_FRAME_NULL;
      p->subs[index].f.subclass = 0;
      *dest = &p->subs[index].f;    
   } else
      dahdi_confmute(p, 0);
}
         
static void handle_alarms(struct dahdi_pvt *p, int alarms)
{
   const char *alarm_str = alarm2str(alarms);

   ast_log(LOG_WARNING, "Detected alarm on channel %d: %s\n", p->channel, alarm_str);
   manager_event(EVENT_FLAG_SYSTEM, "Alarm",
            "Alarm: %s\r\n"
            "Channel: %d\r\n",
            alarm_str, p->channel);
}

static struct ast_frame *dahdi_handle_event(struct ast_channel *ast)
{
   int res, x;
   int index, mysig;
   char *c;
   struct dahdi_pvt *p = ast->tech_pvt;
   pthread_t threadid;
   struct ast_channel *chan;
   struct ast_frame *f;

   index = dahdi_get_index(ast, p, 0);
   mysig = p->sig;
   if (p->outsigmod > -1)
      mysig = p->outsigmod;
   p->subs[index].f.frametype = AST_FRAME_NULL;
   p->subs[index].f.subclass = 0;
   p->subs[index].f.datalen = 0;
   p->subs[index].f.samples = 0;
   p->subs[index].f.mallocd = 0;
   p->subs[index].f.offset = 0;
   p->subs[index].f.src = "dahdi_handle_event";
   p->subs[index].f.data = NULL;
   f = &p->subs[index].f;

   if (index < 0)
      return &p->subs[index].f;
   if (p->fake_event) {
      res = p->fake_event;
      p->fake_event = 0;
   } else
      res = dahdi_get_event(p->subs[index].dfd);

   ast_debug(1, "Got event %s(%d) on channel %d (index %d)\n", event2str(res), res, p->channel, index);

   if (res & (DAHDI_EVENT_PULSEDIGIT | DAHDI_EVENT_DTMFUP)) {
      p->pulsedial =  (res & DAHDI_EVENT_PULSEDIGIT) ? 1 : 0;
      ast_debug(1, "Detected %sdigit '%c'\n", p->pulsedial ? "pulse ": "", res & 0xff);
#ifdef HAVE_PRI
      if (!p->proceeding && ((p->sig == SIG_PRI) || (p->sig == SIG_BRI) || (p->sig == SIG_BRI_PTMP)) && p->pri && (p->pri->overlapdial & DAHDI_OVERLAPDIAL_INCOMING)) {
         /* absorb event */
      } else {
#endif
         p->subs[index].f.frametype = AST_FRAME_DTMF_END;
         p->subs[index].f.subclass = res & 0xff;
#ifdef HAVE_PRI
      }
#endif
      dahdi_handle_dtmfup(ast, index, &f);
      return f;
   }

   if (res & DAHDI_EVENT_DTMFDOWN) {
      ast_debug(1, "DTMF Down '%c'\n", res & 0xff);
      /* Mute conference */
      dahdi_confmute(p, 1);
      p->subs[index].f.frametype = AST_FRAME_DTMF_BEGIN;
      p->subs[index].f.subclass = res & 0xff;
      return &p->subs[index].f;
   }

   switch (res) {
      case DAHDI_EVENT_EC_DISABLED:
         ast_verb(3, "Channel %d echo canceler disabled due to CED detection\n", p->channel);
         p->echocanon = 0;
         break;
      case DAHDI_EVENT_BITSCHANGED:
         ast_log(LOG_WARNING, "Received bits changed on %s signalling?\n", sig2str(p->sig));
      case DAHDI_EVENT_PULSE_START:
         /* Stop tone if there's a pulse start and the PBX isn't started */
         if (!ast->pbx)
            tone_zone_play_tone(p->subs[index].dfd, -1);
         break;   
      case DAHDI_EVENT_DIALCOMPLETE:
         if (p->inalarm) break;
         if ((p->radio || (p->oprmode < 0))) break;
         if (ioctl(p->subs[index].dfd,DAHDI_DIALING,&x) == -1) {
            ast_log(LOG_DEBUG, "DAHDI_DIALING ioctl failed on %s: %s\n",ast->name, strerror(errno));
            return NULL;
         }
         if (!x) { /* if not still dialing in driver */
            dahdi_enable_ec(p);
            if (p->echobreak) {
               dahdi_train_ec(p);
               ast_copy_string(p->dop.dialstr, p->echorest, sizeof(p->dop.dialstr));
               p->dop.op = DAHDI_DIAL_OP_REPLACE;
               res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_DIAL, &p->dop);
               p->echobreak = 0;
            } else {
               p->dialing = 0;
               if ((mysig == SIG_E911) || (mysig == SIG_FGC_CAMA) || (mysig == SIG_FGC_CAMAMF)) {
                  /* if thru with dialing after offhook */
                  if (ast->_state == AST_STATE_DIALING_OFFHOOK) {
                     ast_setstate(ast, AST_STATE_UP);
                     p->subs[index].f.frametype = AST_FRAME_CONTROL;
                     p->subs[index].f.subclass = AST_CONTROL_ANSWER;
                     break;
                  } else { /* if to state wait for offhook to dial rest */
                     /* we now wait for off hook */
                     ast_setstate(ast,AST_STATE_DIALING_OFFHOOK);
                  }
               }
               if (ast->_state == AST_STATE_DIALING) {
                  if ((p->callprogress & CALLPROGRESS_PROGRESS) && CANPROGRESSDETECT(p) && p->dsp && p->outgoing) {
                     ast_debug(1, "Done dialing, but waiting for progress detection before doing more...\n");
                  } else if (p->confirmanswer || (!p->dialednone && ((mysig == SIG_EM) || (mysig == SIG_EM_E1) ||  (mysig == SIG_EMWINK) || (mysig == SIG_FEATD) || (mysig == SIG_FEATDMF_TA) || (mysig == SIG_FEATDMF) || (mysig == SIG_E911) || (mysig == SIG_FGC_CAMA) || (mysig == SIG_FGC_CAMAMF) || (mysig == SIG_FEATB) || (mysig == SIG_SF) || (mysig == SIG_SFWINK) || (mysig == SIG_SF_FEATD) || (mysig == SIG_SF_FEATDMF) || (mysig == SIG_SF_FEATB)))) {
                     ast_setstate(ast, AST_STATE_RINGING);
                  } else if (!p->answeronpolarityswitch) {
                     ast_setstate(ast, AST_STATE_UP);
                     p->subs[index].f.frametype = AST_FRAME_CONTROL;
                     p->subs[index].f.subclass = AST_CONTROL_ANSWER;
                     /* If aops=0 and hops=1, this is necessary */
                     p->polarity = POLARITY_REV;
                  } else {
                     /* Start clean, so we can catch the change to REV polarity when party answers */
                     p->polarity = POLARITY_IDLE;
                  }
               }
            }
         }
         break;
      case DAHDI_EVENT_ALARM:
#ifdef HAVE_PRI
         if ((p->sig == SIG_PRI) || (p->sig == SIG_BRI) || (p->sig == SIG_BRI_PTMP)) {
            if (!p->pri || !p->pri->pri || (pri_get_timer(p->pri->pri, PRI_TIMER_T309) < 0)) {
               /* T309 is not enabled : hangup calls when alarm occurs */
               if (p->call) {
                  if (p->pri && p->pri->pri) {
                     if (!pri_grab(p, p->pri)) {
                        pri_hangup(p->pri->pri, p->call, -1);
                        pri_destroycall(p->pri->pri, p->call);
                        p->call = NULL;
                        pri_rel(p->pri);
                     } else
                        ast_log(LOG_WARNING, "Failed to grab PRI!\n");
                  } else
                     ast_log(LOG_WARNING, "The PRI Call has not been destroyed\n");
               }
               if (p->owner)
                  p->owner->_softhangup |= AST_SOFTHANGUP_DEV;
            }
         }
         if (p->bearer)
            p->bearer->inalarm = 1;
         else
#endif
         p->inalarm = 1;
         res = get_alarms(p);
         handle_alarms(p, res);
#ifdef HAVE_PRI
         if (!p->pri || !p->pri->pri || pri_get_timer(p->pri->pri, PRI_TIMER_T309) < 0) {
            /* fall through intentionally */
         } else {
            break;
         }
#endif
#ifdef HAVE_SS7
         if (p->sig == SIG_SS7)
            break;
#endif
      case DAHDI_EVENT_ONHOOK:
         if (p->radio) {
            p->subs[index].f.frametype = AST_FRAME_CONTROL;
            p->subs[index].f.subclass = AST_CONTROL_RADIO_UNKEY;
            break;
         }
         if (p->oprmode < 0)
         {
            if (p->oprmode != -1) break;
            if ((p->sig == SIG_FXOLS) || (p->sig == SIG_FXOKS) || (p->sig == SIG_FXOGS))
            {
               /* Make sure it starts ringing */
               dahdi_set_hook(p->subs[SUB_REAL].dfd, DAHDI_RINGOFF);
               dahdi_set_hook(p->subs[SUB_REAL].dfd, DAHDI_RING);
               save_conference(p->oprpeer);
               tone_zone_play_tone(p->oprpeer->subs[SUB_REAL].dfd, DAHDI_TONE_RINGTONE);
            }
            break;
         }
         switch (p->sig) {
         case SIG_FXOLS:
         case SIG_FXOGS:
         case SIG_FXOKS:
            p->onhooktime = time(NULL);
            p->msgstate = -1;
            /* Check for some special conditions regarding call waiting */
            if (index == SUB_REAL) {
               /* The normal line was hung up */
               if (p->subs[SUB_CALLWAIT].owner) {
                  /* There's a call waiting call, so ring the phone, but make it unowned in the mean time */
                  swap_subs(p, SUB_CALLWAIT, SUB_REAL);
                  ast_verb(3, "Channel %d still has (callwait) call, ringing phone\n", p->channel);
                  unalloc_sub(p, SUB_CALLWAIT); 
#if 0
                  p->subs[index].needanswer = 0;
                  p->subs[index].needringing = 0;
#endif                  
                  p->callwaitingrepeat = 0;
                  p->cidcwexpire = 0;
                  p->owner = NULL;
                  /* Don't start streaming audio yet if the incoming call isn't up yet */
                  if (p->subs[SUB_REAL].owner->_state != AST_STATE_UP)
                     p->dialing = 1;
                  dahdi_ring_phone(p);
               } else if (p->subs[SUB_THREEWAY].owner) {
                  unsigned int mssinceflash;
                  /* Here we have to retain the lock on both the main channel, the 3-way channel, and
                     the private structure -- not especially easy or clean */
                  while (p->subs[SUB_THREEWAY].owner && ast_channel_trylock(p->subs[SUB_THREEWAY].owner)) {
                     /* Yuck, didn't get the lock on the 3-way, gotta release everything and re-grab! */
                     ast_mutex_unlock(&p->lock);
                     ast_channel_unlock(ast);
                     usleep(1);
                     /* We can grab ast and p in that order, without worry.  We should make sure
                        nothing seriously bad has happened though like some sort of bizarre double
                        masquerade! */
                     ast_channel_lock(ast);
                     ast_mutex_lock(&p->lock);
                     if (p->owner != ast) {
                        ast_log(LOG_WARNING, "This isn't good...\n");
                        return NULL;
                     }
                  }
                  if (!p->subs[SUB_THREEWAY].owner) {
                     ast_log(LOG_NOTICE, "Whoa, threeway disappeared kinda randomly.\n");
                     return NULL;
                  }
                  mssinceflash = ast_tvdiff_ms(ast_tvnow(), p->flashtime);
                  ast_debug(1, "Last flash was %d ms ago\n", mssinceflash);
                  if (mssinceflash < MIN_MS_SINCE_FLASH) {
                     /* It hasn't been long enough since the last flashook.  This is probably a bounce on 
                        hanging up.  Hangup both channels now */
                     if (p->subs[SUB_THREEWAY].owner)
                        ast_queue_hangup(p->subs[SUB_THREEWAY].owner);
                     p->subs[SUB_THREEWAY].owner->_softhangup |= AST_SOFTHANGUP_DEV;
                     ast_debug(1, "Looks like a bounced flash, hanging up both calls on %d\n", p->channel);
                     ast_channel_unlock(p->subs[SUB_THREEWAY].owner);
                  } else if ((ast->pbx) || (ast->_state == AST_STATE_UP)) {
                     if (p->transfer) {
                        /* In any case this isn't a threeway call anymore */
                        p->subs[SUB_REAL].inthreeway = 0;
                        p->subs[SUB_THREEWAY].inthreeway = 0;
                        /* Only attempt transfer if the phone is ringing; why transfer to busy tone eh? */
                        if (!p->transfertobusy && ast->_state == AST_STATE_BUSY) {
                           ast_channel_unlock(p->subs[SUB_THREEWAY].owner);
                           /* Swap subs and dis-own channel */
                           swap_subs(p, SUB_THREEWAY, SUB_REAL);
                           p->owner = NULL;
                           /* Ring the phone */
                           dahdi_ring_phone(p);
                        } else {
                           if ((res = attempt_transfer(p)) < 0) {
                              p->subs[SUB_THREEWAY].owner->_softhangup |= AST_SOFTHANGUP_DEV;
                              if (p->subs[SUB_THREEWAY].owner)
                                 ast_channel_unlock(p->subs[SUB_THREEWAY].owner);
                           } else if (res) {
                              /* Don't actually hang up at this point */
                              if (p->subs[SUB_THREEWAY].owner)
                                 ast_channel_unlock(p->subs[SUB_THREEWAY].owner);
                              break;
                           }
                        }
                     } else {
                        p->subs[SUB_THREEWAY].owner->_softhangup |= AST_SOFTHANGUP_DEV;
                        if (p->subs[SUB_THREEWAY].owner)
                           ast_channel_unlock(p->subs[SUB_THREEWAY].owner);
                     }
                  } else {
                     ast_channel_unlock(p->subs[SUB_THREEWAY].owner);
                     /* Swap subs and dis-own channel */
                     swap_subs(p, SUB_THREEWAY, SUB_REAL);
                     p->owner = NULL;
                     /* Ring the phone */
                     dahdi_ring_phone(p);
                  }
               }
            } else {
               ast_log(LOG_WARNING, "Got a hangup and my index is %d?\n", index);
            }
            /* Fall through */
         default:
            dahdi_disable_ec(p);
            return NULL;
         }
         break;
      case DAHDI_EVENT_RINGOFFHOOK:
         if (p->inalarm) break;
         if (p->oprmode < 0)
         {
            if ((p->sig == SIG_FXOLS) || (p->sig == SIG_FXOKS) || (p->sig == SIG_FXOGS))
            {
               /* Make sure it stops ringing */
               dahdi_set_hook(p->subs[SUB_REAL].dfd, DAHDI_RINGOFF);
               tone_zone_play_tone(p->oprpeer->subs[SUB_REAL].dfd, -1);
               restore_conference(p->oprpeer);
            }
            break;
         }
         if (p->radio)
         {
            p->subs[index].f.frametype = AST_FRAME_CONTROL;
            p->subs[index].f.subclass = AST_CONTROL_RADIO_KEY;
            break;
         }
         /* for E911, its supposed to wait for offhook then dial
            the second half of the dial string */
         if (((mysig == SIG_E911) || (mysig == SIG_FGC_CAMA) || (mysig == SIG_FGC_CAMAMF)) && (ast->_state == AST_STATE_DIALING_OFFHOOK)) {
            c = strchr(p->dialdest, '/');
            if (c)
               c++;
            else
               c = p->dialdest;
            if (*c) snprintf(p->dop.dialstr, sizeof(p->dop.dialstr), "M*0%s#", c);
            else ast_copy_string(p->dop.dialstr,"M*2#", sizeof(p->dop.dialstr));
            if (strlen(p->dop.dialstr) > 4) {
               memset(p->echorest, 'w', sizeof(p->echorest) - 1);
               strcpy(p->echorest + (p->echotraining / 401) + 1, p->dop.dialstr + strlen(p->dop.dialstr) - 2);
               p->echorest[sizeof(p->echorest) - 1] = '\0';
               p->echobreak = 1;
               p->dop.dialstr[strlen(p->dop.dialstr)-2] = '\0';
            } else
               p->echobreak = 0;
            if (ioctl(p->subs[SUB_REAL].dfd, DAHDI_DIAL, &p->dop)) {
               int saveerr = errno;

               x = DAHDI_ONHOOK;
               ioctl(p->subs[SUB_REAL].dfd, DAHDI_HOOK, &x);
               ast_log(LOG_WARNING, "Dialing failed on channel %d: %s\n", p->channel, strerror(saveerr));
               return NULL;
               }
            p->dialing = 1;
            return &p->subs[index].f;
         }
         switch (p->sig) {
         case SIG_FXOLS:
         case SIG_FXOGS:
         case SIG_FXOKS:
            switch (ast->_state) {
            case AST_STATE_RINGING:
               dahdi_enable_ec(p);
               dahdi_train_ec(p);
               p->subs[index].f.frametype = AST_FRAME_CONTROL;
               p->subs[index].f.subclass = AST_CONTROL_ANSWER;
               /* Make sure it stops ringing */
               dahdi_set_hook(p->subs[index].dfd, DAHDI_OFFHOOK);
               ast_debug(1, "channel %d answered\n", p->channel);
               if (p->cidspill) {
                  /* Cancel any running CallerID spill */
                  ast_free(p->cidspill);
                  p->cidspill = NULL;
               }
               p->dialing = 0;
               p->callwaitcas = 0;
               if (p->confirmanswer) {
                  /* Ignore answer if "confirm answer" is enabled */
                  p->subs[index].f.frametype = AST_FRAME_NULL;
                  p->subs[index].f.subclass = 0;
               } else if (!ast_strlen_zero(p->dop.dialstr)) {
                  /* nick@dccinc.com 4/3/03 - fxo should be able to do deferred dialing */
                  res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_DIAL, &p->dop);
                  if (res < 0) {
                     ast_log(LOG_WARNING, "Unable to initiate dialing on trunk channel %d: %s\n", p->channel, strerror(errno));
                     p->dop.dialstr[0] = '\0';
                     return NULL;
                  } else {
                     ast_debug(1, "Sent FXO deferred digit string: %s\n", p->dop.dialstr);
                     p->subs[index].f.frametype = AST_FRAME_NULL;
                     p->subs[index].f.subclass = 0;
                     p->dialing = 1;
                  }
                  p->dop.dialstr[0] = '\0';
                  ast_setstate(ast, AST_STATE_DIALING);
               } else
                  ast_setstate(ast, AST_STATE_UP);
               return &p->subs[index].f;
            case AST_STATE_DOWN:
               ast_setstate(ast, AST_STATE_RING);
               ast->rings = 1;
               p->subs[index].f.frametype = AST_FRAME_CONTROL;
               p->subs[index].f.subclass = AST_CONTROL_OFFHOOK;
               ast_debug(1, "channel %d picked up\n", p->channel);
               return &p->subs[index].f;
            case AST_STATE_UP:
               /* Make sure it stops ringing */
               dahdi_set_hook(p->subs[index].dfd, DAHDI_OFFHOOK);
               /* Okay -- probably call waiting*/
               if (ast_bridged_channel(p->owner))
                  ast_queue_control(p->owner, AST_CONTROL_UNHOLD);
               p->subs[index].needunhold = 1;
               break;
            case AST_STATE_RESERVED:
               /* Start up dialtone */
               if (has_voicemail(p))
                  res = tone_zone_play_tone(p->subs[SUB_REAL].dfd, DAHDI_TONE_STUTTER);
               else
                  res = tone_zone_play_tone(p->subs[SUB_REAL].dfd, DAHDI_TONE_DIALTONE);
               break;
            default:
               ast_log(LOG_WARNING, "FXO phone off hook in weird state %d??\n", ast->_state);
            }
            break;
         case SIG_FXSLS:
         case SIG_FXSGS:
         case SIG_FXSKS:
            if (ast->_state == AST_STATE_RING) {
               p->ringt = p->ringt_base;
            }

            /* If we get a ring then we cannot be in 
             * reversed polarity. So we reset to idle */
            ast_debug(1, "Setting IDLE polarity due "
               "to ring. Old polarity was %d\n", 
               p->polarity);
            p->polarity = POLARITY_IDLE;

            /* Fall through */
         case SIG_EM:
         case SIG_EM_E1:
         case SIG_EMWINK:
         case SIG_FEATD:
         case SIG_FEATDMF:
         case SIG_FEATDMF_TA:
         case SIG_E911:
         case SIG_FGC_CAMA:
         case SIG_FGC_CAMAMF:
         case SIG_FEATB:
         case SIG_SF:
         case SIG_SFWINK:
         case SIG_SF_FEATD:
         case SIG_SF_FEATDMF:
         case SIG_SF_FEATB:
            if (ast->_state == AST_STATE_PRERING)
               ast_setstate(ast, AST_STATE_RING);
            if ((ast->_state == AST_STATE_DOWN) || (ast->_state == AST_STATE_RING)) {
               ast_debug(1, "Ring detected\n");
               p->subs[index].f.frametype = AST_FRAME_CONTROL;
               p->subs[index].f.subclass = AST_CONTROL_RING;
            } else if (p->outgoing && ((ast->_state == AST_STATE_RINGING) || (ast->_state == AST_STATE_DIALING))) {
               ast_debug(1, "Line answered\n");
               if (p->confirmanswer) {
                  p->subs[index].f.frametype = AST_FRAME_NULL;
                  p->subs[index].f.subclass = 0;
               } else {
                  p->subs[index].f.frametype = AST_FRAME_CONTROL;
                  p->subs[index].f.subclass = AST_CONTROL_ANSWER;
                  ast_setstate(ast, AST_STATE_UP);
               }
            } else if (ast->_state != AST_STATE_RING)
               ast_log(LOG_WARNING, "Ring/Off-hook in strange state %d on channel %d\n", ast->_state, p->channel);
            break;
         default:
            ast_log(LOG_WARNING, "Don't know how to handle ring/off hook for signalling %d\n", p->sig);
         }
         break;
      case DAHDI_EVENT_RINGBEGIN:
         switch (p->sig) {
         case SIG_FXSLS:
         case SIG_FXSGS:
         case SIG_FXSKS:
            if (ast->_state == AST_STATE_RING) {
               p->ringt = p->ringt_base;
            }
            break;
         }
         break;
      case DAHDI_EVENT_RINGEROFF:
         if (p->inalarm) break;
         if ((p->radio || (p->oprmode < 0))) break;
         ast->rings++;
         if ((ast->rings > p->cidrings) && (p->cidspill)) {
            ast_log(LOG_WARNING, "Didn't finish Caller-ID spill.  Cancelling.\n");
            ast_free(p->cidspill);
            p->cidspill = NULL;
            p->callwaitcas = 0;
         }
         p->subs[index].f.frametype = AST_FRAME_CONTROL;
         p->subs[index].f.subclass = AST_CONTROL_RINGING;
         break;
      case DAHDI_EVENT_RINGERON:
         break;
      case DAHDI_EVENT_NOALARM:
         p->inalarm = 0;
#ifdef HAVE_PRI
         /* Extremely unlikely but just in case */
         if (p->bearer)
            p->bearer->inalarm = 0;
#endif            
         ast_log(LOG_NOTICE, "Alarm cleared on channel %d\n", p->channel);
         manager_event(EVENT_FLAG_SYSTEM, "AlarmClear",
                        "Channel: %d\r\n", p->channel);
         break;
      case DAHDI_EVENT_WINKFLASH:
         if (p->inalarm) break;
         if (p->radio) break;
         if (p->oprmode < 0) break;
         if (p->oprmode > 1)
         {
            struct dahdi_params par;

            memset(&par, 0, sizeof(par));
            if (ioctl(p->oprpeer->subs[SUB_REAL].dfd, DAHDI_GET_PARAMS, &par) != -1)
            {
               if (!par.rxisoffhook)
               {
                  /* Make sure it stops ringing */
                  dahdi_set_hook(p->oprpeer->subs[SUB_REAL].dfd, DAHDI_RINGOFF);
                  dahdi_set_hook(p->oprpeer->subs[SUB_REAL].dfd, DAHDI_RING);
                  save_conference(p);
                  tone_zone_play_tone(p->subs[SUB_REAL].dfd, DAHDI_TONE_RINGTONE);
               }
            }
            break;
         }
         /* Remember last time we got a flash-hook */
         p->flashtime = ast_tvnow();
         switch (mysig) {
         case SIG_FXOLS:
         case SIG_FXOGS:
         case SIG_FXOKS:
            ast_debug(1, "Winkflash, index: %d, normal: %d, callwait: %d, thirdcall: %d\n",
               index, p->subs[SUB_REAL].dfd, p->subs[SUB_CALLWAIT].dfd, p->subs[SUB_THREEWAY].dfd);
            p->callwaitcas = 0;

            if (index != SUB_REAL) {
               ast_log(LOG_WARNING, "Got flash hook with index %d on channel %d?!?\n", index, p->channel);
               goto winkflashdone;
            }
            
            if (p->subs[SUB_CALLWAIT].owner) {
               /* Swap to call-wait */
               swap_subs(p, SUB_REAL, SUB_CALLWAIT);
               tone_zone_play_tone(p->subs[SUB_REAL].dfd, -1);
               p->owner = p->subs[SUB_REAL].owner;
               ast_debug(1, "Making %s the new owner\n", p->owner->name);
               if (p->owner->_state == AST_STATE_RINGING) {
                  ast_setstate(p->owner, AST_STATE_UP);
                  p->subs[SUB_REAL].needanswer = 1;
               }
               p->callwaitingrepeat = 0;
               p->cidcwexpire = 0;
               /* Start music on hold if appropriate */
               if (!p->subs[SUB_CALLWAIT].inthreeway && ast_bridged_channel(p->subs[SUB_CALLWAIT].owner)) {
                  ast_queue_control_data(p->subs[SUB_CALLWAIT].owner, AST_CONTROL_HOLD,
                     S_OR(p->mohsuggest, NULL),
                     !ast_strlen_zero(p->mohsuggest) ? strlen(p->mohsuggest) + 1 : 0);
               }
               p->subs[SUB_CALLWAIT].needhold = 1;
               if (ast_bridged_channel(p->subs[SUB_REAL].owner)) {
                  ast_queue_control_data(p->subs[SUB_REAL].owner, AST_CONTROL_HOLD,
                     S_OR(p->mohsuggest, NULL),
                     !ast_strlen_zero(p->mohsuggest) ? strlen(p->mohsuggest) + 1 : 0);
               }
               p->subs[SUB_REAL].needunhold = 1;
            } else if (!p->subs[SUB_THREEWAY].owner) {
               if (!p->threewaycalling) {
                  /* Just send a flash if no 3-way calling */
                  p->subs[SUB_REAL].needflash = 1;
                  goto winkflashdone;
               } else if (!check_for_conference(p)) {
                  char cid_num[256];
                  char cid_name[256];

                  cid_num[0] = 0;
                  cid_name[0] = 0;
                  if (p->dahditrcallerid && p->owner) {
                     if (p->owner->cid.cid_num)
                        ast_copy_string(cid_num, p->owner->cid.cid_num, sizeof(cid_num));
                     if (p->owner->cid.cid_name)
                        ast_copy_string(cid_name, p->owner->cid.cid_name, sizeof(cid_name));
                  }
                  /* XXX This section needs much more error checking!!! XXX */
                  /* Start a 3-way call if feasible */
                  if (!((ast->pbx) ||
                        (ast->_state == AST_STATE_UP) ||
                        (ast->_state == AST_STATE_RING))) {
                     ast_debug(1, "Flash when call not up or ringing\n");
                     goto winkflashdone;
                  }
                  if (alloc_sub(p, SUB_THREEWAY)) {
                     ast_log(LOG_WARNING, "Unable to allocate three-way subchannel\n");
                     goto winkflashdone;
                  }
                  /* Make new channel */
                  chan = dahdi_new(p, AST_STATE_RESERVED, 0, SUB_THREEWAY, 0, 0);
                  if (p->dahditrcallerid) {
                     if (!p->origcid_num)
                        p->origcid_num = ast_strdup(p->cid_num);
                     if (!p->origcid_name)
                        p->origcid_name = ast_strdup(p->cid_name);
                     ast_copy_string(p->cid_num, cid_num, sizeof(p->cid_num));
                     ast_copy_string(p->cid_name, cid_name, sizeof(p->cid_name));
                  }
                  /* Swap things around between the three-way and real call */
                  swap_subs(p, SUB_THREEWAY, SUB_REAL);
                  /* Disable echo canceller for better dialing */
                  dahdi_disable_ec(p);
                  res = tone_zone_play_tone(p->subs[SUB_REAL].dfd, DAHDI_TONE_DIALRECALL);
                  if (res)
                     ast_log(LOG_WARNING, "Unable to start dial recall tone on channel %d\n", p->channel);
                  p->owner = chan;
                  if (!chan) {
                     ast_log(LOG_WARNING, "Cannot allocate new structure on channel %d\n", p->channel);
                  } else if (ast_pthread_create_detached(&threadid, NULL, ss_thread, chan)) {
                     ast_log(LOG_WARNING, "Unable to start simple switch on channel %d\n", p->channel);
                     res = tone_zone_play_tone(p->subs[SUB_REAL].dfd, DAHDI_TONE_CONGESTION);
                     dahdi_enable_ec(p);
                     ast_hangup(chan);
                  } else {
                     struct ast_channel *other = ast_bridged_channel(p->subs[SUB_THREEWAY].owner);
                     int way3bridge = 0, cdr3way = 0;
                     
                     if (!other) {
                        other = ast_bridged_channel(p->subs[SUB_REAL].owner);
                     } else
                        way3bridge = 1;
                     
                     if (p->subs[SUB_THREEWAY].owner->cdr)
                        cdr3way = 1;
                     
                     ast_verb(3, "Started three way call on channel %d\n", p->channel);

                     /* Start music on hold if appropriate */
                     if (ast_bridged_channel(p->subs[SUB_THREEWAY].owner)) {
                        ast_queue_control_data(p->subs[SUB_THREEWAY].owner, AST_CONTROL_HOLD,
                           S_OR(p->mohsuggest, NULL),
                           !ast_strlen_zero(p->mohsuggest) ? strlen(p->mohsuggest) + 1 : 0);
                     }
                     p->subs[SUB_THREEWAY].needhold = 1;
                  }
               }
            } else {
               /* Already have a 3 way call */
               if (p->subs[SUB_THREEWAY].inthreeway) {
                  /* Call is already up, drop the last person */
                  ast_debug(1, "Got flash with three way call up, dropping last call on %d\n", p->channel);
                  /* If the primary call isn't answered yet, use it */
                  if ((p->subs[SUB_REAL].owner->_state != AST_STATE_UP) && (p->subs[SUB_THREEWAY].owner->_state == AST_STATE_UP)) {
                     /* Swap back -- we're dropping the real 3-way that isn't finished yet*/
                     swap_subs(p, SUB_THREEWAY, SUB_REAL);
                     p->owner = p->subs[SUB_REAL].owner;
                  }
                  /* Drop the last call and stop the conference */
                  ast_verb(3, "Dropping three-way call on %s\n", p->subs[SUB_THREEWAY].owner->name);
                  p->subs[SUB_THREEWAY].owner->_softhangup |= AST_SOFTHANGUP_DEV;
                  p->subs[SUB_REAL].inthreeway = 0;
                  p->subs[SUB_THREEWAY].inthreeway = 0;
               } else {
                  /* Lets see what we're up to */
                  if (((ast->pbx) || (ast->_state == AST_STATE_UP)) && 
                      (p->transfertobusy || (ast->_state != AST_STATE_BUSY))) {
                     int otherindex = SUB_THREEWAY;
                     struct ast_channel *other = ast_bridged_channel(p->subs[SUB_THREEWAY].owner);
                     int way3bridge = 0, cdr3way = 0;
                     
                     if (!other) {
                        other = ast_bridged_channel(p->subs[SUB_REAL].owner);
                     } else
                        way3bridge = 1;
                     
                     if (p->subs[SUB_THREEWAY].owner->cdr)
                        cdr3way = 1;

                     ast_verb(3, "Building conference on call on %s and %s\n", p->subs[SUB_THREEWAY].owner->name, p->subs[SUB_REAL].owner->name);
                     /* Put them in the threeway, and flip */
                     p->subs[SUB_THREEWAY].inthreeway = 1;
                     p->subs[SUB_REAL].inthreeway = 1;
                     if (ast->_state == AST_STATE_UP) {
                        swap_subs(p, SUB_THREEWAY, SUB_REAL);
                        otherindex = SUB_REAL;
                     }
                     if (p->subs[otherindex].owner && ast_bridged_channel(p->subs[otherindex].owner))
                        ast_queue_control(p->subs[otherindex].owner, AST_CONTROL_UNHOLD);
                     p->subs[otherindex].needunhold = 1;
                     p->owner = p->subs[SUB_REAL].owner;
                     if (ast->_state == AST_STATE_RINGING) {
                        ast_debug(1, "Enabling ringtone on real and threeway\n");
                        res = tone_zone_play_tone(p->subs[SUB_REAL].dfd, DAHDI_TONE_RINGTONE);
                        res = tone_zone_play_tone(p->subs[SUB_THREEWAY].dfd, DAHDI_TONE_RINGTONE);
                     }
                  } else {
                     ast_verb(3, "Dumping incomplete call on on %s\n", p->subs[SUB_THREEWAY].owner->name);
                     swap_subs(p, SUB_THREEWAY, SUB_REAL);
                     p->subs[SUB_THREEWAY].owner->_softhangup |= AST_SOFTHANGUP_DEV;
                     p->owner = p->subs[SUB_REAL].owner;
                     if (p->subs[SUB_REAL].owner && ast_bridged_channel(p->subs[SUB_REAL].owner))
                        ast_queue_control(p->subs[SUB_REAL].owner, AST_CONTROL_UNHOLD);
                     p->subs[SUB_REAL].needunhold = 1;
                     dahdi_enable_ec(p);
                  }
                     
               }
            }
         winkflashdone:              
            update_conf(p);
            break;
         case SIG_EM:
         case SIG_EM_E1:
         case SIG_FEATD:
         case SIG_SF:
         case SIG_SFWINK:
         case SIG_SF_FEATD:
         case SIG_FXSLS:
         case SIG_FXSGS:
            if (option_debug) {
               if (p->dialing)
                  ast_debug(1, "Ignoring wink on channel %d\n", p->channel);
               else
                  ast_debug(1, "Got wink in weird state %d on channel %d\n", ast->_state, p->channel);
            }
            break;
         case SIG_FEATDMF_TA:
            switch (p->whichwink) {
            case 0:
               ast_debug(1, "ANI2 set to '%d' and ANI is '%s'\n", p->owner->cid.cid_ani2, p->owner->cid.cid_ani);
               snprintf(p->dop.dialstr, sizeof(p->dop.dialstr), "M*%d%s#", p->owner->cid.cid_ani2, p->owner->cid.cid_ani);
               break;
            case 1:
               ast_copy_string(p->dop.dialstr, p->finaldial, sizeof(p->dop.dialstr));
               break;
            case 2:
               ast_log(LOG_WARNING, "Received unexpected wink on channel of type SIG_FEATDMF_TA\n");
               return NULL;
            }
            p->whichwink++;
            /* Fall through */
         case SIG_FEATDMF:
         case SIG_E911:
         case SIG_FGC_CAMAMF:
         case SIG_FGC_CAMA:
         case SIG_FEATB:
         case SIG_SF_FEATDMF:
         case SIG_SF_FEATB:
         case SIG_EMWINK:
            /* FGD MF and EMWINK *Must* wait for wink */
            if (!ast_strlen_zero(p->dop.dialstr)) {
               res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_DIAL, &p->dop);
               if (res < 0) {
                  ast_log(LOG_WARNING, "Unable to initiate dialing on trunk channel %d: %s\n", p->channel, strerror(errno));
                  p->dop.dialstr[0] = '\0';
                  return NULL;
               } else 
                  ast_debug(1, "Sent deferred digit string: %s\n", p->dop.dialstr);
            }
            p->dop.dialstr[0] = '\0';
            break;
         default:
            ast_log(LOG_WARNING, "Don't know how to handle ring/off hook for signalling %d\n", p->sig);
         }
         break;
      case DAHDI_EVENT_HOOKCOMPLETE:
         if (p->inalarm) break;
         if ((p->radio || (p->oprmode < 0))) break;
         switch (mysig) {
         case SIG_FXSLS:  /* only interesting for FXS */
         case SIG_FXSGS:
         case SIG_FXSKS:
         case SIG_EM:
         case SIG_EM_E1:
         case SIG_EMWINK:
         case SIG_FEATD:
         case SIG_SF:
         case SIG_SFWINK:
         case SIG_SF_FEATD:
            if (!ast_strlen_zero(p->dop.dialstr)) {
               res = ioctl(p->subs[SUB_REAL].dfd, DAHDI_DIAL, &p->dop);
               if (res < 0) {
                  ast_log(LOG_WARNING, "Unable to initiate dialing on trunk channel %d: %s\n", p->channel, strerror(errno));
                  p->dop.dialstr[0] = '\0';
                  return NULL;
               } else 
                  ast_debug(1, "Sent deferred digit string: %s\n", p->dop.dialstr);
            }
            p->dop.dialstr[0] = '\0';
            p->dop.op = DAHDI_DIAL_OP_REPLACE;
            break;
         case SIG_FEATDMF:
         case SIG_FEATDMF_TA:
         case SIG_E911:
         case SIG_FGC_CAMA:
         case SIG_FGC_CAMAMF:
         case SIG_FEATB:
         case SIG_SF_FEATDMF:
         case SIG_SF_FEATB:
            ast_debug(1, "Got hook complete in MF FGD, waiting for wink now on channel %d\n",p->channel);
            break;
         default:
            break;
         }
         break;
      case DAHDI_EVENT_POLARITY:
         /*
          * If we get a Polarity Switch event, this could be
          * due to line seizure, remote end connect or remote end disconnect.
          *
          * Check to see if we should change the polarity state and
          * mark the channel as UP or if this is an indication
          * of remote end disconnect.
          */

         if (p->polarityonanswerdelay > 0) {
            /* check if event is not too soon after OffHook or Answer */
               if (ast_tvdiff_ms(ast_tvnow(), p->polaritydelaytv) > p->polarityonanswerdelay) {
               switch (ast->_state) {
               case AST_STATE_DIALING:       /*!< Digits (or equivalent) have been dialed */
               case AST_STATE_RINGING:       /*!< Remote end is ringing */
                  if (p->answeronpolarityswitch) {
                     ast_debug(1, "Answering on polarity switch! channel %d\n", p->channel);
                     ast_setstate(p->owner, AST_STATE_UP);
                     p->polarity = POLARITY_REV;
                     if (p->hanguponpolarityswitch) {
                        p->polaritydelaytv = ast_tvnow();
                     }
                  } else {
                     ast_debug(1, "Ignore Answer on polarity switch, channel %d\n", p->channel);
                  }
                  break;
               case AST_STATE_UP:         /*!< Line is up */
               case AST_STATE_RING:       /*!< Line is ringing */
                  if (p->hanguponpolarityswitch) {
                     ast_debug(1, "HangingUp on polarity switch! channel %d\n", p->channel);
                     ast_softhangup(p->owner, AST_SOFTHANGUP_EXPLICIT);
                     p->polarity = POLARITY_IDLE;
                  } else {
                     ast_debug(1, "Ignore Hangup on polarity switch, channel %d\n", p->channel);
                  }
                  break;

               case AST_STATE_DOWN:       /*!< Channel is down and available */
               case AST_STATE_RESERVED:      /*!< Channel is down, but reserved */
               case AST_STATE_OFFHOOK:       /*!< Channel is off hook */
               case AST_STATE_BUSY:       /*!< Line is busy */
               case AST_STATE_DIALING_OFFHOOK:     /*!< Digits (or equivalent) have been dialed while offhook */
               case AST_STATE_PRERING:       /*!< Channel has detected an incoming call and is waiting for ring */
               default:
                  if (p->answeronpolarityswitch || p->hanguponpolarityswitch) {
                     ast_debug(1, "Ignoring Polarity switch on channel %d, state %d\n", p->channel, ast->_state);
                  }

               }

            } else {
               /* event is too soon after OffHook or Answer */
               switch (ast->_state) {
               case AST_STATE_DIALING:       /*!< Digits (or equivalent) have been dialed */
               case AST_STATE_RINGING:       /*!< Remote end is ringing */
                  if (p->answeronpolarityswitch) {
                     ast_debug(1, "Polarity switch detected but NOT answering (too close to OffHook event) on channel %d, state %d\n", p->channel, ast->_state);
                  }
                  break;

               case AST_STATE_UP:         /*!< Line is up */
               case AST_STATE_RING:       /*!< Line is ringing */
                  if (p->hanguponpolarityswitch) {
                     ast_debug(1, "Polarity switch detected but NOT hanging up (too close to Answer event) on channel %d, state %d\n", p->channel, ast->_state);
                  }
                  break;

               default: 
                  if (p->answeronpolarityswitch || p->hanguponpolarityswitch) {
                     ast_debug(1, "Polarity switch detected (too close to previous event) on channel %d, state %d\n", p->channel, ast->_state);
                  }
               }
            }
         }
                        /* Added more log_debug information below to provide a better indication of what is going on */
         ast_debug(1, "Polarity Reversal event occured - DEBUG 2: channel %d, state %d, pol= %d, aonp= %d, honp= %d, pdelay= %d, tv= %d\n", p->channel, ast->_state, p->polarity, p->answeronpolarityswitch, p->hanguponpolarityswitch, p->polarityonanswerdelay, ast_tvdiff_ms(ast_tvnow(), p->polaritydelaytv) );
         break;
      default:
         ast_debug(1, "Dunno what to do with event %d on channel %d\n", res, p->channel);
   }
   return &p->subs[index].f;
}

static struct ast_frame *__dahdi_exception(struct ast_channel *ast)
{
   struct dahdi_pvt *p = ast->tech_pvt;
   int res;
   int usedindex=-1;
   int index;
   struct ast_frame *f;


   index = dahdi_get_index(ast, p, 1);
   
   p->subs[index].f.frametype = AST_FRAME_NULL;
   p->subs[index].f.datalen = 0;
   p->subs[index].f.samples = 0;
   p->subs[index].f.mallocd = 0;
   p->subs[index].f.offset = 0;
   p->subs[index].f.subclass = 0;
   p->subs[index].f.delivery = ast_tv(0,0);
   p->subs[index].f.src = "dahdi_exception";
   p->subs[index].f.data = NULL;
   
   
   if ((!p->owner) && (!(p->radio || (p->oprmode < 0)))) {
      /* If nobody owns us, absorb the event appropriately, otherwise
         we loop indefinitely.  This occurs when, during call waiting, the
         other end hangs up our channel so that it no longer exists, but we
         have neither FLASH'd nor ONHOOK'd to signify our desire to
         change to the other channel. */
      if (p->fake_event) {
         res = p->fake_event;
         p->fake_event = 0;
      } else
         res = dahdi_get_event(p->subs[SUB_REAL].dfd);
      /* Switch to real if there is one and this isn't something really silly... */
      if ((res != DAHDI_EVENT_RINGEROFF) && (res != DAHDI_EVENT_RINGERON) &&
         (res != DAHDI_EVENT_HOOKCOMPLETE)) {
         ast_debug(1, "Restoring owner of channel %d on event %d\n", p->channel, res);
         p->owner = p->subs[SUB_REAL].owner;
         if (p->owner && ast_bridged_channel(p->owner))
            ast_queue_control(p->owner, AST_CONTROL_UNHOLD);
         p->subs[SUB_REAL].needunhold = 1;
      }
      switch (res) {
      case DAHDI_EVENT_ONHOOK:
         dahdi_disable_ec(p);
         if (p->owner) {
            ast_verb(3, "Channel %s still has call, ringing phone\n", p->owner->name);
            dahdi_ring_phone(p);
            p->callwaitingrepeat = 0;
            p->cidcwexpire = 0;
         } else
            ast_log(LOG_WARNING, "Absorbed on hook, but nobody is left!?!?\n");
         update_conf(p);
         break;
      case DAHDI_EVENT_RINGOFFHOOK:
         dahdi_enable_ec(p);
         dahdi_set_hook(p->subs[SUB_REAL].dfd, DAHDI_OFFHOOK);
         if (p->owner && (p->owner->_state == AST_STATE_RINGING)) {
            p->subs[SUB_REAL].needanswer = 1;
            p->dialing = 0;
         }
         break;
      case DAHDI_EVENT_HOOKCOMPLETE:
      case DAHDI_EVENT_RINGERON:
      case DAHDI_EVENT_RINGEROFF:
         /* Do nothing */
         break;
      case DAHDI_EVENT_WINKFLASH:
         p->flashtime = ast_tvnow();
         if (p->owner) {
            ast_verb(3, "Channel %d flashed to other channel %s\n", p->channel, p->owner->name);
            if (p->owner->_state != AST_STATE_UP) {
               /* Answer if necessary */
               usedindex = dahdi_get_index(p->owner, p, 0);
               if (usedindex > -1) {
                  p->subs[usedindex].needanswer = 1;
               }
               ast_setstate(p->owner, AST_STATE_UP);
            }
            p->callwaitingrepeat = 0;
            p->cidcwexpire = 0;
            if (ast_bridged_channel(p->owner))
               ast_queue_control(p->owner, AST_CONTROL_UNHOLD);
            p->subs[SUB_REAL].needunhold = 1;
         } else
            ast_log(LOG_WARNING, "Absorbed on hook, but nobody is left!?!?\n");
         update_conf(p);
         break;
      default:
         ast_log(LOG_WARNING, "Don't know how to absorb event %s\n", event2str(res));
      }
      f = &p->subs[index].f;
      return f;
   }
   if (!(p->radio || (p->oprmode < 0))) 
      ast_debug(1, "Exception on %d, channel %d\n", ast->fds[0],p->channel);
   /* If it's not us, return NULL immediately */
   if (ast != p->owner) {
      ast_log(LOG_WARNING, "We're %s, not %s\n", ast->name, p->owner->name);
      f = &p->subs[index].f;
      return f;
   }
   f = dahdi_handle_event(ast);
   return f;
}

static struct ast_frame *dahdi_exception(struct ast_channel *ast)
{
   struct dahdi_pvt *p = ast->tech_pvt;
   struct ast_frame *f;
   ast_mutex_lock(&p->lock);
   f = __dahdi_exception(ast);
   ast_mutex_unlock(&p->lock);
   return f;
}

static struct ast_frame  *dahdi_read(struct ast_channel *ast)
{
   struct dahdi_pvt *p = ast->tech_pvt;
   int res;
   int index;
   void *readbuf;
   struct ast_frame *f;

   while (ast_mutex_trylock(&p->lock)) {
      CHANNEL_DEADLOCK_AVOIDANCE(ast);
   }

   index = dahdi_get_index(ast, p, 0);
   
   /* Hang up if we don't really exist */
   if (index < 0) {
      ast_log(LOG_WARNING, "We dont exist?\n");
      ast_mutex_unlock(&p->lock);
      return NULL;
   }
   
   if ((p->radio || (p->oprmode < 0)) && p->inalarm) {
      ast_mutex_unlock(&p->lock);
      return NULL;
   }

   p->subs[index].f.frametype = AST_FRAME_NULL;
   p->subs[index].f.datalen = 0;
   p->subs[index].f.samples = 0;
   p->subs[index].f.mallocd = 0;
   p->subs[index].f.offset = 0;
   p->subs[index].f.subclass = 0;
   p->subs[index].f.delivery = ast_tv(0,0);
   p->subs[index].f.src = "dahdi_read";
   p->subs[index].f.data = NULL;
   
   /* make sure it sends initial key state as first frame */
   if ((p->radio || (p->oprmode < 0)) && (!p->firstradio))
   {
      struct dahdi_params ps;

      memset(&ps, 0, sizeof(ps));
      ps.channo = p->channel;
      if (ioctl(p->subs[SUB_REAL].dfd, DAHDI_GET_PARAMS, &ps) < 0) {
         ast_mutex_unlock(&p->lock);
         return NULL;
      }
      p->firstradio = 1;
      p->subs[index].f.frametype = AST_FRAME_CONTROL;
      if (ps.rxisoffhook)
      {
         p->subs[index].f.subclass = AST_CONTROL_RADIO_KEY;
      }
      else
      {
         p->subs[index].f.subclass = AST_CONTROL_RADIO_UNKEY;
      }
      ast_mutex_unlock(&p->lock);
      return &p->subs[index].f;
   }
   if (p->ringt == 1) {
      ast_mutex_unlock(&p->lock);
      return NULL;
   }
   else if (p->ringt > 0) 
      p->ringt--;

   if (p->subs[index].needringing) {
      /* Send ringing frame if requested */
      p->subs[index].needringing = 0;
      p->subs[index].f.frametype = AST_FRAME_CONTROL;
      p->subs[index].f.subclass = AST_CONTROL_RINGING;
      ast_setstate(ast, AST_STATE_RINGING);
      ast_mutex_unlock(&p->lock);
      return &p->subs[index].f;
   }

   if (p->subs[index].needbusy) {
      /* Send busy frame if requested */
      p->subs[index].needbusy = 0;
      p->subs[index].f.frametype = AST_FRAME_CONTROL;
      p->subs[index].f.subclass = AST_CONTROL_BUSY;
      ast_mutex_unlock(&p->lock);
      return &p->subs[index].f;
   }

   if (p->subs[index].needcongestion) {
      /* Send congestion frame if requested */
      p->subs[index].needcongestion = 0;
      p->subs[index].f.frametype = AST_FRAME_CONTROL;
      p->subs[index].f.subclass = AST_CONTROL_CONGESTION;
      ast_mutex_unlock(&p->lock);
      return &p->subs[index].f;
   }

   if (p->subs[index].needcallerid) {
      ast_set_callerid(ast, S_OR(p->lastcid_num, NULL),
                     S_OR(p->lastcid_name, NULL),
                     S_OR(p->lastcid_num, NULL)
                     );
      p->subs[index].needcallerid = 0;
   }
   
   if (p->subs[index].needanswer) {
      /* Send answer frame if requested */
      p->subs[index].needanswer = 0;
      p->subs[index].f.frametype = AST_FRAME_CONTROL;
      p->subs[index].f.subclass = AST_CONTROL_ANSWER;
      ast_mutex_unlock(&p->lock);
      return &p->subs[index].f;
   }  
   
   if (p->subs[index].needflash) {
      /* Send answer frame if requested */
      p->subs[index].needflash = 0;
      p->subs[index].f.frametype = AST_FRAME_CONTROL;
      p->subs[index].f.subclass = AST_CONTROL_FLASH;
      ast_mutex_unlock(&p->lock);
      return &p->subs[index].f;
   }  
   
   if (p->subs[index].needhold) {
      /* Send answer frame if requested */
      p->subs[index].needhold = 0;
      p->subs[index].f.frametype = AST_FRAME_CONTROL;
      p->subs[index].f.subclass = AST_CONTROL_HOLD;
      ast_mutex_unlock(&p->lock);
      ast_debug(1, "Sending hold on '%s'\n", ast->name);
      return &p->subs[index].f;
   }  
   
   if (p->subs[index].needunhold) {
      /* Send answer frame if requested */
      p->subs[index].needunhold = 0;
      p->subs[index].f.frametype = AST_FRAME_CONTROL;
      p->subs[index].f.subclass = AST_CONTROL_UNHOLD;
      ast_mutex_unlock(&p->lock);
      ast_debug(1, "Sending unhold on '%s'\n", ast->name);
      return &p->subs[index].f;
   }  
   
   if (ast->rawreadformat == AST_FORMAT_SLINEAR) {
      if (!p->subs[index].linear) {
         p->subs[index].linear = 1;
         res = dahdi_setlinear(p->subs[index].dfd, p->subs[index].linear);
         if (res) 
            ast_log(LOG_WARNING, "Unable to set channel %d (index %d) to linear mode.\n", p->channel, index);
      }
   } else if ((ast->rawreadformat == AST_FORMAT_ULAW) ||
         (ast->rawreadformat == AST_FORMAT_ALAW)) {
      if (p->subs[index].linear) {
         p->subs[index].linear = 0;
         res = dahdi_setlinear(p->subs[index].dfd, p->subs[index].linear);
         if (res) 
            ast_log(LOG_WARNING, "Unable to set channel %d (index %d) to companded mode.\n", p->channel, index);
      }
   } else {
      ast_log(LOG_WARNING, "Don't know how to read frames in format %s\n", ast_getformatname(ast->rawreadformat));
      ast_mutex_unlock(&p->lock);
      return NULL;
   }
   readbuf = ((unsigned char *)p->subs[index].buffer) + AST_FRIENDLY_OFFSET;
   CHECK_BLOCKING(ast);
   res = read(p->subs[index].dfd, readbuf, p->subs[index].linear ? READ_SIZE * 2 : READ_SIZE);
   ast_clear_flag(ast, AST_FLAG_BLOCKING);
   /* Check for hangup */
   if (res < 0) {
      f = NULL;
      if (res == -1)  {
         if (errno == EAGAIN) {
            /* Return "NULL" frame if there is nobody there */
            ast_mutex_unlock(&p->lock);
            return &p->subs[index].f;
         } else if (errno == ELAST) {
            f = __dahdi_exception(ast);
         } else
            ast_log(LOG_WARNING, "dahdi_rec: %s\n", strerror(errno));
      }
      ast_mutex_unlock(&p->lock);
      return f;
   }
   if (res != (p->subs[index].linear ? READ_SIZE * 2 : READ_SIZE)) {
      ast_debug(1, "Short read (%d/%d), must be an event...\n", res, p->subs[index].linear ? READ_SIZE * 2 : READ_SIZE);
      f = __dahdi_exception(ast);
      ast_mutex_unlock(&p->lock);
      return f;
   }
   if (p->tdd) { /* if in TDD mode, see if we receive that */
      int c;

      c = tdd_feed(p->tdd,readbuf,READ_SIZE);
      if (c < 0) {
         ast_debug(1,"tdd_feed failed\n");
         ast_mutex_unlock(&p->lock);
         return NULL;
      }
      if (c) { /* if a char to return */
         p->subs[index].f.subclass = 0;
         p->subs[index].f.frametype = AST_FRAME_TEXT;
         p->subs[index].f.mallocd = 0;
         p->subs[index].f.offset = AST_FRIENDLY_OFFSET;
         p->subs[index].f.data = p->subs[index].buffer + AST_FRIENDLY_OFFSET;
         p->subs[index].f.datalen = 1;
         *((char *) p->subs[index].f.data) = c;
         ast_mutex_unlock(&p->lock);
         return &p->subs[index].f;
      }
   }
   /* Ensure the CW timer decrements only on a single subchannel */
   if (p->callwaitingrepeat && dahdi_get_index(ast, p, 1) == SUB_REAL) {
      p->callwaitingrepeat--;
   }
   if (p->cidcwexpire)
      p->cidcwexpire--;
   /* Repeat callwaiting */
   if (p->callwaitingrepeat == 1) {
      p->callwaitrings++;
      dahdi_callwait(ast);
   }
   /* Expire CID/CW */
   if (p->cidcwexpire == 1) {
      ast_verb(3, "CPE does not support Call Waiting Caller*ID.\n");
      restore_conference(p);
   }
   if (p->subs[index].linear) {
      p->subs[index].f.datalen = READ_SIZE * 2;
   } else 
      p->subs[index].f.datalen = READ_SIZE;

   /* Handle CallerID Transmission */
   if ((p->owner == ast) && p->cidspill &&((ast->_state == AST_STATE_UP) || (ast->rings == p->cidrings))) {
      send_callerid(p);
   }

   p->subs[index].f.frametype = AST_FRAME_VOICE;
   p->subs[index].f.subclass = ast->rawreadformat;
   p->subs[index].f.samples = READ_SIZE;
   p->subs[index].f.mallocd = 0;
   p->subs[index].f.offset = AST_FRIENDLY_OFFSET;
   p->subs[index].f.data = p->subs[index].buffer + AST_FRIENDLY_OFFSET / sizeof(p->subs[index].buffer[0]);
#if 0
   ast_debug(1, "Read %d of voice on %s\n", p->subs[index].f.datalen, ast->name);
#endif   
   if (p->dialing || /* Transmitting something */
      (index && (ast->_state != AST_STATE_UP)) || /* Three-way or callwait that isn't up */
      ((index == SUB_CALLWAIT) && !p->subs[SUB_CALLWAIT].inthreeway) /* Inactive and non-confed call-wait */
      ) {
      /* Whoops, we're still dialing, or in a state where we shouldn't transmit....
         don't send anything */
      p->subs[index].f.frametype = AST_FRAME_NULL;
      p->subs[index].f.subclass = 0;
      p->subs[index].f.samples = 0;
      p->subs[index].f.mallocd = 0;
      p->subs[index].f.offset = 0;
      p->subs[index].f.data = NULL;
      p->subs[index].f.datalen= 0;
   }
   if (p->dsp && (!p->ignoredtmf || p->callwaitcas || p->busydetect  || p->callprogress) && !index) {
      /* Perform busy detection. etc on the dahdi line */
      f = ast_dsp_process(ast, p->dsp, &p->subs[index].f);
      if (f) {
         if ((f->frametype == AST_FRAME_CONTROL) && (f->subclass == AST_CONTROL_BUSY)) {
            if ((ast->_state == AST_STATE_UP) && !p->outgoing) {
               /* Treat this as a "hangup" instead of a "busy" on the assumption that
                  a busy  */
               f = NULL;
            }
         } else if (f->frametype == AST_FRAME_DTMF) {
#ifdef HAVE_PRI
            if (!p->proceeding && ((p->sig == SIG_PRI) || (p->sig == SIG_BRI) || (p->sig == SIG_BRI_PTMP)) && p->pri && 
                ((!p->outgoing && (p->pri->overlapdial & DAHDI_OVERLAPDIAL_INCOMING)) ||
                 (p->outgoing && (p->pri->overlapdial & DAHDI_OVERLAPDIAL_OUTGOING)))) {
               /* Don't accept in-band DTMF when in overlap dial mode */
               f->frametype = AST_FRAME_NULL;
               f->subclass = 0;
            }
#endif            
            /* DSP clears us of being pulse */
            p->pulsedial = 0;
         }
      }
   } else 
      f = &p->subs[index].f; 

   if (f && (f->frametype == AST_FRAME_DTMF))
      dahdi_handle_dtmfup(ast, index, &f);

   /* If we have a fake_event, trigger exception to handle it */
   if (p->fake_event)
      ast_set_flag(ast, AST_FLAG_EXCEPTION);

   ast_mutex_unlock(&p->lock);
   return f;
}

static int my_dahdi_write(struct dahdi_pvt *p, unsigned char *buf, int len, int index, int linear)
{
   int sent=0;
   int size;
   int res;
   int fd;
   fd = p->subs[index].dfd;
   while (len) {
      size = len;
      if (size > (linear ? READ_SIZE * 2 : READ_SIZE))
         size = (linear ? READ_SIZE * 2 : READ_SIZE);
      res = write(fd, buf, size);
      if (res != size) {
         ast_debug(1, "Write returned %d (%s) on channel %d\n", res, strerror(errno), p->channel);
         return sent;
      }
      len -= size;
      buf += size;
   }
   return sent;
}

static int dahdi_write(struct ast_channel *ast, struct ast_frame *frame)
{
   struct dahdi_pvt *p = ast->tech_pvt;
   int res;
   int index;
   index = dahdi_get_index(ast, p, 0);
   if (index < 0) {
      ast_log(LOG_WARNING, "%s doesn't really exist?\n", ast->name);
      return -1;
   }

#if 0
#ifdef HAVE_PRI
   ast_mutex_lock(&p->lock);
   if (!p->proceeding && p->sig==SIG_PRI && p->pri && !p->outgoing) {
      if (p->pri->pri) {      
         if (!pri_grab(p, p->pri)) {
               pri_progress(p->pri->pri,p->call, PVT_TO_CHANNEL(p), !p->digital);
               pri_rel(p->pri);
         } else
               ast_log(LOG_WARNING, "Unable to grab PRI on span %d\n", p->span);
      }
      p->proceeding=1;
   }
   ast_mutex_unlock(&p->lock);
#endif
#endif
   /* Write a frame of (presumably voice) data */
   if (frame->frametype != AST_FRAME_VOICE) {
      if (frame->frametype != AST_FRAME_IMAGE)
         ast_log(LOG_WARNING, "Don't know what to do with frame type '%d'\n", frame->frametype);
      return 0;
   }
   if ((frame->subclass != AST_FORMAT_SLINEAR) && 
       (frame->subclass != AST_FORMAT_ULAW) &&
       (frame->subclass != AST_FORMAT_ALAW)) {
      ast_log(LOG_WARNING, "Cannot handle frames in %d format\n", frame->subclass);
      return -1;
   }
   if (p->dialing) {
      ast_debug(1, "Dropping frame since I'm still dialing on %s...\n",ast->name);
      return 0;
   }
   if (!p->owner) {
      ast_debug(1, "Dropping frame since there is no active owner on %s...\n",ast->name);
      return 0;
   }
   if (p->cidspill) {
      ast_debug(1, "Dropping frame since I've still got a callerid spill\n");
      return 0;
   }
   /* Return if it's not valid data */
   if (!frame->data || !frame->datalen)
      return 0;

   if (frame->subclass == AST_FORMAT_SLINEAR) {
      if (!p->subs[index].linear) {
         p->subs[index].linear = 1;
         res = dahdi_setlinear(p->subs[index].dfd, p->subs[index].linear);
         if (res)
            ast_log(LOG_WARNING, "Unable to set linear mode on channel %d\n", p->channel);
      }
      res = my_dahdi_write(p, (unsigned char *)frame->data, frame->datalen, index, 1);
   } else {
      /* x-law already */
      if (p->subs[index].linear) {
         p->subs[index].linear = 0;
         res = dahdi_setlinear(p->subs[index].dfd, p->subs[index].linear);
         if (res)
            ast_log(LOG_WARNING, "Unable to set companded mode on channel %d\n", p->channel);
      }
      res = my_dahdi_write(p, (unsigned char *)frame->data, frame->datalen, index, 0);
   }
   if (res < 0) {
      ast_log(LOG_WARNING, "write failed: %s\n", strerror(errno));
      return -1;
   } 
   return 0;
}

static int dahdi_indicate(struct ast_channel *chan, int condition, const void *data, size_t datalen)
{
   struct dahdi_pvt *p = chan->tech_pvt;
   int res=-1;
   int index;
   int func = DAHDI_FLASH;
   ast_mutex_lock(&p->lock);
   index = dahdi_get_index(chan, p, 0);
   ast_debug(1, "Requested indication %d on channel %s\n", condition, chan->name);
   if (index == SUB_REAL) {
      switch (condition) {
      case AST_CONTROL_BUSY:
#ifdef HAVE_PRI
         if (p->priindication_oob && ((p->sig == SIG_PRI) || (p->sig == SIG_BRI) || (p->sig == SIG_BRI_PTMP))) {
            chan->hangupcause = AST_CAUSE_USER_BUSY;
            chan->_softhangup |= AST_SOFTHANGUP_DEV;
            res = 0;
         } else if (!p->progress && 
               ((p->sig == SIG_PRI) || (p->sig == SIG_BRI) || (p->sig == SIG_BRI_PTMP))
               && p->pri && !p->outgoing) {
            if (p->pri->pri) {      
               if (!pri_grab(p, p->pri)) {
                  pri_progress(p->pri->pri,p->call, PVT_TO_CHANNEL(p), 1);
                  pri_rel(p->pri);
               }
               else
                  ast_log(LOG_WARNING, "Unable to grab PRI on span %d\n", p->span);
            }
            p->progress = 1;
            res = tone_zone_play_tone(p->subs[index].dfd, DAHDI_TONE_BUSY);
         } else
#endif
            res = tone_zone_play_tone(p->subs[index].dfd, DAHDI_TONE_BUSY);
         break;
      case AST_CONTROL_RINGING:
#ifdef HAVE_PRI
         if ((!p->alerting) && ((p->sig == SIG_PRI) || (p->sig == SIG_BRI) || (p->sig == SIG_BRI_PTMP)) 
               && p->pri && !p->outgoing && (chan->_state != AST_STATE_UP)) {
            if (p->pri->pri) {      
               if (!pri_grab(p, p->pri)) {
                  pri_acknowledge(p->pri->pri,p->call, PVT_TO_CHANNEL(p), !p->digital);
                  pri_rel(p->pri);
               }
               else
                  ast_log(LOG_WARNING, "Unable to grab PRI on span %d\n", p->span);
            }
            p->alerting = 1;
         }

#endif
#ifdef HAVE_SS7
         if ((!p->alerting) && (p->sig == SIG_SS7) && p->ss7 && !p->outgoing && (chan->_state != AST_STATE_UP)) {
            if (p->ss7->ss7) {
               ss7_grab(p, p->ss7);
               
               if ((isup_far(p->ss7->ss7, p->ss7call)) != -1)
                  p->rlt = 1;
               if (p->rlt != 1) /* No need to send CPG if call will be RELEASE */
                  isup_cpg(p->ss7->ss7, p->ss7call, CPG_EVENT_ALERTING);
               p->alerting = 1;
               ss7_rel(p->ss7);
            }
         }
#endif
            
         res = tone_zone_play_tone(p->subs[index].dfd, DAHDI_TONE_RINGTONE);
         
         if (chan->_state != AST_STATE_UP) {
            if ((chan->_state != AST_STATE_RING) ||
               ((p->sig != SIG_FXSKS) &&
             (p->sig != SIG_FXSLS) &&
             (p->sig != SIG_FXSGS)))
            ast_setstate(chan, AST_STATE_RINGING);
         }
         break;
      case AST_CONTROL_PROCEEDING:
         ast_debug(1,"Received AST_CONTROL_PROCEEDING on %s\n",chan->name);
#ifdef HAVE_PRI
         if (!p->proceeding && ((p->sig == SIG_PRI) || (p->