codec_dahdi.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * DAHDI native transcoding support
 *
 * Copyright (C) 1999 - 2008, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 * Kevin P. Fleming <kpfleming@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 Translate between various formats natively through DAHDI transcoding
 *
 * \ingroup codecs
 */

/*** MODULEINFO
   <depend>dahdi</depend>
 ***/

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 224933 $")

#include <fcntl.h>
#include <netinet/in.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/poll.h>
#include <dahdi/user.h>

#include "asterisk/lock.h"
#include "asterisk/translate.h"
#include "asterisk/config.h"
#include "asterisk/module.h"
#include "asterisk/cli.h"
#include "asterisk/channel.h"
#include "asterisk/utils.h"
#include "asterisk/linkedlists.h"
#include "asterisk/ulaw.h"

#define BUFFER_SIZE 8000

#define G723_SAMPLES 240
#define G729_SAMPLES 160

static unsigned int global_useplc = 0;

static struct channel_usage {
   int total;
   int encoders;
   int decoders;
} channels;

static char *handle_cli_transcoder_show(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a);

static struct ast_cli_entry cli[] = {
   AST_CLI_DEFINE(handle_cli_transcoder_show, "Display DAHDI transcoder utilization.")
};

struct format_map {
   unsigned int map[32][32];
};

static struct format_map global_format_map = { { { 0 } } };

struct translator {
   struct ast_translator t;
   AST_LIST_ENTRY(translator) entry;
};

static AST_LIST_HEAD_STATIC(translators, translator);

struct codec_dahdi_pvt {
   int fd;
   struct dahdi_transcoder_formats fmts;
   unsigned int softslin:1;
   unsigned int fake:2;
   uint16_t required_samples;
   uint16_t samples_in_buffer;
   uint8_t ulaw_buffer[1024];
};

/* Only used by a decoder */
static int ulawtolin(struct ast_trans_pvt *pvt)
{
   struct codec_dahdi_pvt *dahdip = pvt->pvt;
   int i = dahdip->required_samples;
   uint8_t *src = &dahdip->ulaw_buffer[0];
   int16_t *dst = (int16_t *)pvt->outbuf + pvt->datalen;

   /* convert and copy in outbuf */
   while (i--) {
      *dst++ = AST_MULAW(*src++);
   }

   return 0;
}

/* Only used by an encoder. */
static int lintoulaw(struct ast_trans_pvt *pvt, struct ast_frame *f)
{
   struct codec_dahdi_pvt *dahdip = pvt->pvt;
   int i = f->samples;
   uint8_t *dst = &dahdip->ulaw_buffer[dahdip->samples_in_buffer];
   int16_t *src = f->data;

   if (dahdip->samples_in_buffer + i > sizeof(dahdip->ulaw_buffer)) {
      ast_log(LOG_ERROR, "Out of buffer space!\n");
      return -i;
   }

   while (i--) {
      *dst++ = AST_LIN2MU(*src++);
   }

   dahdip->samples_in_buffer += f->samples;
   return 0;
}

static char *handle_cli_transcoder_show(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct channel_usage copy;

   switch (cmd) {
   case CLI_INIT:
      e->command = "transcoder show";
      e->usage =
         "Usage: transcoder show\n"
         "       Displays channel utilization of DAHDI transcoder(s).\n";
      return NULL;
   case CLI_GENERATE:
      return NULL;
   }

   if (a->argc != 2)
      return CLI_SHOWUSAGE;

   copy = channels;

   if (copy.total == 0)
      ast_cli(a->fd, "No DAHDI transcoders found.\n");
   else
      ast_cli(a->fd, "%d/%d encoders/decoders of %d channels are in use.\n", copy.encoders, copy.decoders, copy.total);

   return CLI_SUCCESS;
}

static void dahdi_write_frame(struct codec_dahdi_pvt *dahdip, const uint8_t *buffer, const ssize_t count)
{
   int res;
   struct pollfd p = {0};
   if (!count) return;
   res = write(dahdip->fd, buffer, count);
   if (option_verbose > 10) {
      if (-1 == res) {
         ast_log(LOG_ERROR, "Failed to write to transcoder: %s\n", strerror(errno));
      }
      if (count != res) {
         ast_log(LOG_ERROR, "Requested write of %zd bytes, but only wrote %d bytes.\n", count, res);
      }
   }
   p.fd = dahdip->fd;
   p.events = POLLOUT;
   res = poll(&p, 1, 50);
}

static int dahdi_encoder_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
{
   struct codec_dahdi_pvt *dahdip = pvt->pvt;

   if (!f->subclass) {
      /* We're just faking a return for calculation purposes. */
      dahdip->fake = 2;
      pvt->samples = f->samples;
      return 0;
   }

   /* Buffer up the packets and send them to the hardware if we
    * have enough samples set up. */
   if (dahdip->softslin) {
      if (lintoulaw(pvt, f)) {
          return -1;
      }
   } else {
      /* NOTE:  If softslin support is not needed, and the sample
       * size is equal to the required sample size, we wouldn't
       * need this copy operation.  But at the time this was
       * written, only softslin is supported. */
      if (dahdip->samples_in_buffer + f->samples > sizeof(dahdip->ulaw_buffer)) {
         ast_log(LOG_ERROR, "Out of buffer space.\n");
         return -1;
      }
      memcpy(&dahdip->ulaw_buffer[dahdip->samples_in_buffer], f->data, f->samples);
      dahdip->samples_in_buffer += f->samples;
   }

   while (dahdip->samples_in_buffer > dahdip->required_samples) {
      dahdi_write_frame(dahdip, dahdip->ulaw_buffer, dahdip->required_samples);
      dahdip->samples_in_buffer -= dahdip->required_samples;
      if (dahdip->samples_in_buffer) {
         /* Shift any remaining bytes down. */
         memmove(dahdip->ulaw_buffer, &dahdip->ulaw_buffer[dahdip->required_samples],
            dahdip->samples_in_buffer);
      }
   }
   pvt->samples += f->samples;
   pvt->datalen = 0;
   return -1;
}

static struct ast_frame *dahdi_encoder_frameout(struct ast_trans_pvt *pvt)
{
   struct codec_dahdi_pvt *dahdip = pvt->pvt;
   int res;

   if (2 == dahdip->fake) {
      dahdip->fake = 1;
      pvt->f.frametype = AST_FRAME_VOICE;
      pvt->f.subclass = 0;
      pvt->f.samples = dahdip->required_samples;
      pvt->f.data = NULL;
      pvt->f.offset = 0;
      pvt->f.datalen = 0;
      pvt->f.mallocd = 0;
      pvt->samples = 0;

      return ast_frisolate(&pvt->f);

   } else if (1 == dahdip->fake) {
      dahdip->fake = 0;
      return NULL;
   }

   res = read(dahdip->fd, pvt->outbuf + pvt->datalen, pvt->t->buf_size - pvt->datalen);
   if (-1 == res) {
      if (EWOULDBLOCK == errno) {
         /* Nothing waiting... */
         return NULL;
      } else {
         ast_log(LOG_ERROR, "Failed to read from transcoder: %s\n", strerror(errno));
         return NULL;
      }
   } else {
      pvt->f.datalen = res;
      pvt->f.samples = dahdip->required_samples;
      pvt->f.frametype = AST_FRAME_VOICE;
      pvt->f.subclass = 1 <<  (pvt->t->dstfmt);
      pvt->f.mallocd = 0;
      pvt->f.offset = AST_FRIENDLY_OFFSET;
      pvt->f.src = pvt->t->name;
      pvt->f.data = pvt->outbuf;

      pvt->samples = 0;
      pvt->datalen = 0;
      return ast_frisolate(&pvt->f);
   }

   /* Shouldn't get here... */
   return NULL;
}

static int dahdi_decoder_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
{
   struct codec_dahdi_pvt *dahdip = pvt->pvt;

   if (!f->subclass) {
      /* We're just faking a return for calculation purposes. */
      dahdip->fake = 2;
      pvt->samples = f->samples;
      return 0;
   }

   if (!f->datalen) {
      if (f->samples != dahdip->required_samples) {
         ast_log(LOG_ERROR, "%d != %d %d\n", f->samples, dahdip->required_samples, f->datalen);
      }
   }
   dahdi_write_frame(dahdip, f->data, f->datalen);
   pvt->samples += f->samples;
   pvt->datalen = 0;
   return -1;
}

static struct ast_frame *dahdi_decoder_frameout(struct ast_trans_pvt *pvt)
{
   int res;
   struct codec_dahdi_pvt *dahdip = pvt->pvt;

   if (2 == dahdip->fake) {
      dahdip->fake = 1;
      pvt->f.frametype = AST_FRAME_VOICE;
      pvt->f.subclass = 0;
      pvt->f.samples = dahdip->required_samples;
      pvt->f.data = NULL;
      pvt->f.offset = 0;
      pvt->f.datalen = 0;
      pvt->f.mallocd = 0;
      pvt->samples = 0;
      return ast_frisolate(&pvt->f);
   } else if (1 == dahdip->fake) {
      pvt->samples = 0;
      dahdip->fake = 0;
      return NULL;
   }

   /* Let's check to see if there is a new frame for us.... */
   if (dahdip->softslin) {
      res = read(dahdip->fd, dahdip->ulaw_buffer, sizeof(dahdip->ulaw_buffer));
   } else {
      res = read(dahdip->fd, pvt->outbuf + pvt->datalen, pvt->t->buf_size - pvt->datalen);
   }

   if (-1 == res) {
      if (EWOULDBLOCK == errno) {
         /* Nothing waiting... */
         return NULL;
      } else {
         ast_log(LOG_ERROR, "Failed to read from transcoder: %s\n", strerror(errno));
         return NULL;
      }
   } else {
      if (dahdip->softslin) {
         ulawtolin(pvt);
         pvt->f.datalen = res * 2;
      } else {
         pvt->f.datalen = res;
      }
      pvt->datalen = 0;
      pvt->f.frametype = AST_FRAME_VOICE;
      pvt->f.subclass = 1 <<  (pvt->t->dstfmt);
      pvt->f.mallocd = 0;
      pvt->f.offset = AST_FRIENDLY_OFFSET;
      pvt->f.src = pvt->t->name;
      pvt->f.data = pvt->outbuf;
      pvt->f.samples = dahdip->required_samples;
      pvt->samples = 0;

      return ast_frisolate(&pvt->f);
   }

   /* Shouldn't get here... */
   return NULL;
}


static void dahdi_destroy(struct ast_trans_pvt *pvt)
{
   struct codec_dahdi_pvt *dahdip = pvt->pvt;

   switch (dahdip->fmts.dstfmt) {
   case AST_FORMAT_G729A:
   case AST_FORMAT_G723_1:
      ast_atomic_fetchadd_int(&channels.encoders, -1);
      break;
   default:
      ast_atomic_fetchadd_int(&channels.decoders, -1);
      break;
   }

   close(dahdip->fd);
}

static int dahdi_translate(struct ast_trans_pvt *pvt, int dest, int source)
{
   /* Request translation through zap if possible */
   int fd;
   struct codec_dahdi_pvt *dahdip = pvt->pvt;
   int flags;
   int tried_once = 0;
   const char *dev_filename = "/dev/dahdi/transcode";

   if ((fd = open(dev_filename, O_RDWR)) < 0) {
      ast_log(LOG_ERROR, "Failed to open %s: %s\n", dev_filename, strerror(errno));
      return -1;
   }

   dahdip->fmts.srcfmt = (1 << source);
   dahdip->fmts.dstfmt = (1 << dest);

   ast_debug(1, "Opening transcoder channel from %d to %d.\n", source, dest);

retry:
   if (ioctl(fd, DAHDI_TC_ALLOCATE, &dahdip->fmts)) {
      if ((ENODEV == errno) && !tried_once) {
         /* We requested to translate to/from an unsupported
          * format.  Most likely this is because signed linear
          * was not supported by any hardware devices even
          * though this module always registers signed linear
          * support. In this case we'll retry, requesting
          * support for ULAW instead of signed linear and then
          * we'll just convert from ulaw to signed linear in
          * software. */
         if (AST_FORMAT_SLINEAR == dahdip->fmts.srcfmt) {
            ast_debug(1, "Using soft_slin support on source\n");
            dahdip->softslin = 1;
            dahdip->fmts.srcfmt = AST_FORMAT_ULAW;
         } else if (AST_FORMAT_SLINEAR == dahdip->fmts.dstfmt) {
            ast_debug(1, "Using soft_slin support on destination\n");
            dahdip->softslin = 1;
            dahdip->fmts.dstfmt = AST_FORMAT_ULAW;
         }
         tried_once = 1;
         goto retry;
      }
      ast_log(LOG_ERROR, "Unable to attach to transcoder: %s\n", strerror(errno));
      close(fd);

      return -1;
   }

   flags = fcntl(fd, F_GETFL);
   if (flags > - 1) {
      if (fcntl(fd, F_SETFL, flags | O_NONBLOCK))
         ast_log(LOG_WARNING, "Could not set non-block mode!\n");
   }

   dahdip->fd = fd;

   dahdip->required_samples = ((dahdip->fmts.dstfmt|dahdip->fmts.srcfmt)&AST_FORMAT_G723_1) ? G723_SAMPLES : G729_SAMPLES;

   switch (dahdip->fmts.dstfmt) {
   case AST_FORMAT_G729A:
      ast_atomic_fetchadd_int(&channels.encoders, +1);
      break;
   case AST_FORMAT_G723_1:
      ast_atomic_fetchadd_int(&channels.encoders, +1);
      break;
   default:
      ast_atomic_fetchadd_int(&channels.decoders, +1);
      break;
   }

   return 0;
}

static int dahdi_new(struct ast_trans_pvt *pvt)
{
   return dahdi_translate(pvt, pvt->t->dstfmt, pvt->t->srcfmt);
}

static struct ast_frame *fakesrc_sample(void)
{
   /* Don't bother really trying to test hardware ones. */
   static struct ast_frame f = {
      .frametype = AST_FRAME_VOICE,
      .samples = 160,
      .src = __PRETTY_FUNCTION__
   };

   return &f;
}

static int is_encoder(struct translator *zt)
{
   if (zt->t.srcfmt&(AST_FORMAT_ULAW|AST_FORMAT_ALAW|AST_FORMAT_SLINEAR)) {
      return 1;
   } else {
      return 0;
   }
}

static int register_translator(int dst, int src)
{
   struct translator *zt;
   int res;

   if (!(zt = ast_calloc(1, sizeof(*zt)))) {
      return -1;
   }

   snprintf((char *) (zt->t.name), sizeof(zt->t.name), "zap%sto%s",
       ast_getformatname((1 << src)), ast_getformatname((1 << dst)));
   zt->t.srcfmt = (1 << src);
   zt->t.dstfmt = (1 << dst);
   zt->t.buf_size = BUFFER_SIZE;
   if (is_encoder(zt)) {
      zt->t.framein = dahdi_encoder_framein;
      zt->t.frameout = dahdi_encoder_frameout;
#if 0
      zt->t.buffer_samples = 0;
#endif
   } else {
      zt->t.framein = dahdi_decoder_framein;
      zt->t.frameout = dahdi_decoder_frameout;
#if 0
      if (AST_FORMAT_G723_1 == zt->t.srcfmt) {
         zt->t.plc_samples = G723_SAMPLES;
      } else {
         zt->t.plc_samples = G729_SAMPLES;
      }
      zt->t.buffer_samples = zt->t.plc_samples * 8;
#endif
   }
   zt->t.destroy = dahdi_destroy;
   zt->t.buffer_samples = 0;
   zt->t.newpvt = dahdi_new;
   zt->t.sample = fakesrc_sample;
#if 0
   zt->t.useplc = global_useplc;
#endif
   zt->t.useplc = 0;
   zt->t.native_plc = 0;

   zt->t.desc_size = sizeof(struct codec_dahdi_pvt);
   if ((res = ast_register_translator(&zt->t))) {
      ast_free(zt);
      return -1;
   }

   AST_LIST_LOCK(&translators);
   AST_LIST_INSERT_HEAD(&translators, zt, entry);
   AST_LIST_UNLOCK(&translators);

   global_format_map.map[dst][src] = 1;

   return res;
}

static void drop_translator(int dst, int src)
{
   struct translator *cur;

   AST_LIST_LOCK(&translators);
   AST_LIST_TRAVERSE_SAFE_BEGIN(&translators, cur, entry) {
      if (cur->t.srcfmt != src)
         continue;

      if (cur->t.dstfmt != dst)
         continue;

      AST_LIST_REMOVE_CURRENT(entry);
      ast_unregister_translator(&cur->t);
      ast_free(cur);
      global_format_map.map[dst][src] = 0;
      break;
   }
   AST_LIST_TRAVERSE_SAFE_END;
   AST_LIST_UNLOCK(&translators);
}

static void unregister_translators(void)
{
   struct translator *cur;

   AST_LIST_LOCK(&translators);
   while ((cur = AST_LIST_REMOVE_HEAD(&translators, entry))) {
      ast_unregister_translator(&cur->t);
      ast_free(cur);
   }
   AST_LIST_UNLOCK(&translators);
}

static int parse_config(int reload)
{
   struct ast_variable *var;
   struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
   struct ast_config *cfg = ast_config_load("codecs.conf", config_flags);

   if (cfg == NULL)
      return 0;
   if (cfg == CONFIG_STATUS_FILEUNCHANGED)
      return 0;

   for (var = ast_variable_browse(cfg, "plc"); var; var = var->next) {
          if (!strcasecmp(var->name, "genericplc")) {
             global_useplc = ast_true(var->value);
             ast_verb(3, "codec_dahdi: %susing generic PLC\n",
            global_useplc ? "" : "not ");
          }
   }

   ast_config_destroy(cfg);
   return 0;
}

static void build_translators(struct format_map *map, unsigned int dstfmts, unsigned int srcfmts)
{
   unsigned int src, dst;

   for (src = 0; src < 32; src++) {
      for (dst = 0; dst < 32; dst++) {
         if (!(srcfmts & (1 << src)))
            continue;

         if (!(dstfmts & (1 << dst)))
            continue;

         if (global_format_map.map[dst][src])
            continue;

         if (!register_translator(dst, src))
            map->map[dst][src] = 1;
      }
   }
}

static int find_transcoders(void)
{
   struct dahdi_transcoder_info info = { 0, };
   struct format_map map = { { { 0 } } };
   int fd, res;
   unsigned int x, y;

   if ((fd = open("/dev/dahdi/transcode", O_RDWR)) < 0) {
      ast_log(LOG_ERROR, "Failed to open /dev/dahdi/transcode: %s\n", strerror(errno));
      return 0;
   }

   for (info.tcnum = 0; !(res = ioctl(fd, DAHDI_TC_GETINFO, &info)); info.tcnum++) {
      if (option_verbose > 1)
         ast_verbose(VERBOSE_PREFIX_2 "Found transcoder '%s'.\n", info.name);

      /* Complex codecs need to support signed linear.  If the
       * hardware transcoder does not natively support signed linear
       * format, we will emulate it in software directly in this
       * module. Also, do not allow direct ulaw/alaw to complex
       * codec translation, since that will prevent the generic PLC
       * functions from working. */
      if (info.dstfmts & (AST_FORMAT_ULAW | AST_FORMAT_ALAW)) {
         info.dstfmts |= AST_FORMAT_SLINEAR;
         info.dstfmts &= ~(AST_FORMAT_ULAW | AST_FORMAT_ALAW);
      }
      if (info.srcfmts & (AST_FORMAT_ULAW | AST_FORMAT_ALAW)) {
         info.srcfmts |= AST_FORMAT_SLINEAR;
         info.srcfmts &= ~(AST_FORMAT_ULAW | AST_FORMAT_ALAW);
      }

      build_translators(&map, info.dstfmts, info.srcfmts);
      ast_atomic_fetchadd_int(&channels.total, info.numchannels / 2);

   }

   close(fd);

   if (!info.tcnum && (option_verbose > 1))
      ast_verbose(VERBOSE_PREFIX_2 "No hardware transcoders found.\n");

   for (x = 0; x < 32; x++) {
      for (y = 0; y < 32; y++) {
         if (!map.map[x][y] && global_format_map.map[x][y])
            drop_translator(x, y);
      }
   }

   return 0;
}

static int reload(void)
{
   struct translator *cur;

   if (parse_config(1))
      return AST_MODULE_LOAD_DECLINE;

   AST_LIST_LOCK(&translators);
   AST_LIST_TRAVERSE(&translators, cur, entry)
      cur->t.useplc = global_useplc;
   AST_LIST_UNLOCK(&translators);

   return AST_MODULE_LOAD_SUCCESS;
}

static int unload_module(void)
{
   ast_cli_unregister_multiple(cli, ARRAY_LEN(cli));
   unregister_translators();

   return 0;
}

static int load_module(void)
{
   ast_ulaw_init();
   if (parse_config(0))
      return AST_MODULE_LOAD_DECLINE;
   find_transcoders();
   ast_cli_register_multiple(cli, ARRAY_LEN(cli));
   return AST_MODULE_LOAD_SUCCESS;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "Generic DAHDI Transcoder Codec Translator",
      .load = load_module,
      .unload = unload_module,
      .reload = reload,
          );