parser.c

SDP文件解析代码

        }
        if (dsc->unidentified_attributes_count <
            UNIDENTIFIED_ATTRIBUTES_MAX_COUNT)
        {
          dsc->unidentified_attributes
            [dsc->unidentified_attributes_count] =
            strdup (longfsdp_buf);
          dsc->unidentified_attributes_count++;
        }
      }
      NEXT_LINE (p);
    }
    else if (sscanf (p, "a=%20s", fsdp_buf[0]) == 1)
    {
      /* session-level property attributes */
      if (!strncmp (fsdp_buf[0], "recvonly", 8))
        dsc->a_sendrecv_mode = FSDP_SENDRECV_RECVONLY;
      else if (!strncmp (fsdp_buf[0], "sendonly", 8))
        dsc->a_sendrecv_mode = FSDP_SENDRECV_SENDONLY;
      else if (!strncmp (fsdp_buf[0], "inactive", 8))
        dsc->a_sendrecv_mode = FSDP_SENDRECV_INACTIVE;
      else if (!strncmp (fsdp_buf[0], "sendrecv", 8))
        dsc->a_sendrecv_mode = FSDP_SENDRECV_SENDRECV;
      else
      {
        /* ignore unknown attributes, but provide access to them */
        *longfsdp_buf = '\0';
        strncat (longfsdp_buf, fsdp_buf[0], MAXLONGFIELDLEN-1);
        if (NULL == dsc->unidentified_attributes)
        {
          dsc->unidentified_attributes_count = 0;
          dsc->unidentified_attributes =
            calloc (UNIDENTIFIED_ATTRIBUTES_MAX_COUNT,
                    sizeof (char *));
        }
        if (dsc->unidentified_attributes_count <
            UNIDENTIFIED_ATTRIBUTES_MAX_COUNT)
        {
          dsc->unidentified_attributes
            [dsc->unidentified_attributes_count] =
            strdup (longfsdp_buf);
          dsc->unidentified_attributes_count++;
        }
      }
      NEXT_LINE (p);
    }
    else
      return FSDPE_INVALID_ATTRIBUTE;
  }

  /***************************************************************************/
  /* B) parse media-level descriptions                                       */
  /***************************************************************************/
  p2 = p;
  j = 0;
  while ((*p2 != '\0') && !strncmp (p2, "m=", 2))
  {
    char c;
    j++;
    NEXT_LINE (p2);
    while (sscanf (p2, "%c=", &c) == 1)
    {
      if (c == 'i' || c == 'c' || c == 'b' || c == 'k' || c == 'a')
      {
        NEXT_LINE (p2);
      }
      else if (c == 'm')
      {
        break;
      }
      else
      {
        return FSDPE_INVALID_LINE;
      }
    }
  }
  dsc->media_announcements_count = j;
  if (dsc->media_announcements_count == 0)
  {
    ;
    /*return FSDPE_MISSING_MEDIA; */
  }
  else
  {				/* dsc->media_announcements_count > 0 */
    dsc->media_announcements =
      calloc (j, sizeof (fsdp_media_announcement_t *));
    for (j = 0; j < dsc->media_announcements_count; j++)
    {
      fsdp_media_announcement_t *media = NULL;
      /* `m=' line (media name, transport address and format list) */
      /* m=<media>  <port>  <transport> <fmt list> */
      /* The max. string lengths are subject to change */
      if (sscanf (p, "m=%11s %8s %7s %" MLFLENS "[^\r\n]",
                  fsdp_buf[0], fsdp_buf[1], fsdp_buf[2],
                  longfsdp_buf) != 4)
      {
        return FSDPE_INVALID_MEDIA;
      }
      else
      {
        dsc->media_announcements[j] =
          calloc (1, sizeof (fsdp_media_announcement_t));
        media = dsc->media_announcements[j];
        if (!strncmp (fsdp_buf[0], "audio", 5))
          media->media_type = FSDP_MEDIA_AUDIO;
        else if (!strncmp (fsdp_buf[0], "video", 5))
          media->media_type = FSDP_MEDIA_VIDEO;
        else if (!strncmp (fsdp_buf[0], "application", 11))
          media->media_type = FSDP_MEDIA_APPLICATION;
        else if (!strncmp (fsdp_buf[0], "data", 4))
          media->media_type = FSDP_MEDIA_DATA;
        else if (!strncmp (fsdp_buf[0], "control", 7))
          media->media_type = FSDP_MEDIA_CONTROL;
        else
          return FSDPE_UNKNOWN_MEDIA_TYPE;
        {			/* try to get port specification as port/number */
          char *slash;
          if ((slash = strchr (fsdp_buf[1], '/')))
          {
            *slash = '\0';
            slash++;
            media->port = strtol (fsdp_buf[1], NULL, 10);
            media->port_count = strtol (slash, NULL, 10);
          }
          else
          {
            media->port = strtol (fsdp_buf[1], NULL, 10);
            media->port_count = 0;
          }
        }
        if (!strncmp (fsdp_buf[2], "RTP/AVP", 7))
          media->transport = FSDP_TP_RTP_AVP;
        else if (!strncmp (fsdp_buf[2], "udp", 3))
          media->transport = FSDP_TP_UDP;
        else if (!strncmp (fsdp_buf[2], "TCP", 3))
          media->transport = FSDP_TP_TCP;
        else if (!strncmp (fsdp_buf[2], "UDPTL", 5))
          media->transport = FSDP_TP_UDPTL;
        else if (!strncmp (fsdp_buf[2], "vat", 3))
          media->transport = FSDP_TP_VAT;
        else if (!strncmp (fsdp_buf[2], "rtp", 3))
          media->transport = FSDP_TP_OLD_RTP;
        else
          return FSDPE_UNKNOWN_MEDIA_TRANSPORT;
        {
          unsigned int k = 0;
          char *s = longfsdp_buf;
          while (NULL != (s = strchr (s, ' ')))
          {
            k++;
            if (NULL != s)
              s++;
          }
          k++;		/* when there is no space left, count the last format */
          media->formats_count = k;
          media->formats = calloc (k, sizeof (char *));
          s = longfsdp_buf;
          for (k = 0; k < media->formats_count; k++)
          {
            char *space = strchr (s, ' ');
            if (NULL != space)
              *space = '\0';
            media->formats[k] = strdup (s);
            s = space + 1;
          }
        }
        NEXT_LINE (p);
      }

      /* `i=' line (media title) [optional] */
      /* i=<media title> */
      if (!strncmp (p, "i=", 2)
          && sscanf (p, "i=%" MLFLENS "[^\r\n]", longfsdp_buf))
      {
        media->i_title = strdup (longfsdp_buf);
        NEXT_LINE (p);
      }
      else
      {
        /* (optional) information absent */
      }

      /* `c=' line (connection information - overrides session-level
         line) [optional if provided at session-level] */
      /* c=<network type> <address type> <connection address> */
      result = fsdp_parse_c (&p, &(media->c_network_type),
                             &(media->c_address_type),
                             &(media->c_address));
      if (result != FSDPE_OK)
        return result;

      /* `b=' lines (bandwidth information) [optional] */
      /* b=<modifier>:<bandwidth-value> */
      result = fsdp_parse_b (&p, &(media->bw_modifiers),
                             &(media->bw_modifiers_count));
      if (FSDPE_OK != result)
        return result;

      /* `k=' line (encryption key) [optional] */
      /* k=<method> 
         k=<method>:<encryption key> */
      result = fsdp_parse_k (&p, &(media->k_encryption_method),
                             &(media->k_encryption_content));
      if (result != FSDPE_OK)
        return result;

      /* B.1) Attributes */

      /* `a=' lines (zero or more media attribute lines) [optional] */
      /* a=<attribute>
         a=<attribute>:<value> */
      while (!strncmp (p, "a=", 2))
      {
        if (sscanf
            (p, "a=%9[^:\r\n]:%" MLFLENS "[^\r\n]", fsdp_buf[0],
             longfsdp_buf) == 2)
        {
          /* media-level value attributes */
          if (!strncmp (fsdp_buf[0], "ptime", 5))
            media->a_ptime = strtoul (longfsdp_buf, NULL, 10);
          else if (!strncmp (fsdp_buf[0], "maxptime", 8))
            media->a_maxptime = strtoul (longfsdp_buf, NULL, 10);
          else if (!strncmp (fsdp_buf[0], "rtpmap", 6))
            fsdp_parse_rtpmap (&(media->a_rtpmaps),
                               &(media->a_rtpmaps_count),
                               longfsdp_buf);
          else if (!strncmp (fsdp_buf[0], "orient", 6))
          {
            if (!strncmp (longfsdp_buf, "portrait", 8))
              media->a_orient = FSDP_ORIENT_PORTRAIT;
            else if (!strncmp (longfsdp_buf, "landscape", 9))
              media->a_orient = FSDP_ORIENT_LANDSCAPE;
            else if (!strncmp (longfsdp_buf, "seascape", 9))
              media->a_orient = FSDP_ORIENT_SEASCAPE;
          }
          else if (!strncmp (fsdp_buf[0], "sdplang", 7))
          {
            if (NULL == dsc->a_sdplangs)
            {
              media->a_sdplangs_count = 0;
              media->a_sdplangs =
                calloc (SDPLANGS_MAX_COUNT, sizeof (char *));
            }
            if (media->a_sdplangs_count < SDPLANGS_MAX_COUNT)
            {
              media->a_sdplangs[dsc->a_sdplangs_count] =
                strdup (longfsdp_buf);
              media->a_sdplangs_count++;
            }
          }
          else if (!strncmp (fsdp_buf[0], "lang", 4))
          {
            if (NULL == dsc->a_langs)
            {
              media->a_langs_count = 0;
              media->a_langs =
                calloc (SDPLANGS_MAX_COUNT, sizeof (char *));
            }
            if (media->a_langs_count < SDPLANGS_MAX_COUNT)
            {
              media->a_langs[dsc->a_langs_count] =
                strdup (longfsdp_buf);
              media->a_langs_count++;
            }
          }
          else if (!strncmp (fsdp_buf[0], "control", 7))
          {
            if (NULL == media->a_controls)
            {
              media->a_controls_count = 0;
              media->a_controls =
                calloc (SDPCONTROLS_MAX_COUNT, sizeof (char *));
            }
            if (media->a_controls_count < SDPCONTROLS_MAX_COUNT)
            {
              media->a_controls[media->a_controls_count] =
                strdup (longfsdp_buf);
              media->a_controls_count++;
            }
          }
          else if (!strncmp (fsdp_buf[0], "range", 5))
          {
            if (media->a_range)
              free (media->a_range);
            media->a_range = strdup (fsdp_buf[1]);
          }
          else if (!strncmp (fsdp_buf[0], "framerate", 9))
            media->a_framerate = strtod (longfsdp_buf, NULL);
          else if (!strncmp (fsdp_buf[0], "fmtp", 4))
          {
            if (NULL == media->a_fmtps)
            {
              media->a_fmtps_count = 0;
              media->a_fmtps =
                calloc (SDPLANGS_MAX_COUNT, sizeof (char *));
            }
            if (media->a_fmtps_count < SDPLANGS_MAX_COUNT)
            {
              media->a_fmtps[media->a_fmtps_count] =
                strdup (longfsdp_buf);
              media->a_fmtps_count++;
            }
          }
          else if (!strncmp (fsdp_buf[0], "rtcp", 4))
          {
            int opts = 0;
            /* rtcp attribute: a=rtcp:<port> <nettype> <addrtype> <address> */
            opts =
              sscanf (longfsdp_buf, "%lu %2s %3s %" MSFLENS "s",
                      &wuint[0], fsdp_buf[0], fsdp_buf[1],
                      fsdp_buf[2]);
            if (opts >= 1)
            {
              media->a_rtcp_port = wuint[0];
              if (opts >= 2)
              {
                if (!strncmp (fsdp_buf[0], "IN", 2))
                {
                  media->a_rtcp_network_type =
                    FSDP_NETWORK_TYPE_INET;
                }	/* else
                           ; TODO: define error code? */
                if (opts >= 3)
                {
                  if (!strncmp (fsdp_buf[1], "IP4", 3))
                    media->a_rtcp_address_type =
                      FSDP_ADDRESS_TYPE_IPV4;
                  else if (!strncmp (fsdp_buf[1], "IP6", 3))
                    media->a_rtcp_address_type =
                      FSDP_ADDRESS_TYPE_IPV6;
                  else
                    return FSDPE_INVALID_CONNECTION_NETTYPE;
                  /*add specific code? */
                  if (opts >= 4)
                    media->a_rtcp_address =
                      strdup (fsdp_buf[2]);
                }
              }
            }
          }
          else
          {
            /* ignore unknown attributes, but provide access to them */
            *fsdp_buf[1] = '\0';
            strncat (fsdp_buf[1], fsdp_buf[0], MAXSHORTFIELDLEN-1);
            strncat (fsdp_buf[1], ":", MAXSHORTFIELDLEN-strlen(fsdp_buf[1])-1);
            strncat (fsdp_buf[1], longfsdp_buf, MAXSHORTFIELDLEN-strlen(fsdp_buf[1])-1);
            if (NULL == media->unidentified_attributes)
            {
              media->unidentified_attributes_count = 0;
              media->unidentified_attributes =
                calloc (UNIDENTIFIED_ATTRIBUTES_MAX_COUNT,
                        sizeof (char *));
            }
            if (media->unidentified_attributes_count <
                UNIDENTIFIED_ATTRIBUTES_MAX_COUNT)
            {
              media->unidentified_attributes
                [media->unidentified_attributes_count] =
                strdup (fsdp_buf[1]);
              media->unidentified_attributes_count++;
            }
          }
          NEXT_LINE (p);
        }
        else if (sscanf (p, "a=%8s", fsdp_buf[0]) == 1)
        {
          /* media-level property attributes */
          if (!strncmp (fsdp_buf[0], "recvonly", 8))
            media->a_sendrecv_mode = FSDP_SENDRECV_RECVONLY;
          else if (!strncmp (fsdp_buf[0], "sendonly", 8))
            media->a_sendrecv_mode = FSDP_SENDRECV_SENDONLY;
          else if (!strncmp (fsdp_buf[0], "inactive", 8))
            media->a_sendrecv_mode = FSDP_SENDRECV_INACTIVE;
          else if (!strncmp (fsdp_buf[0], "sendrecv", 8))
            media->a_sendrecv_mode = FSDP_SENDRECV_SENDRECV;
          else
          {
            /* ignore unknown attributes, but provide access to them */
            *longfsdp_buf = '\0';
            strncat (longfsdp_buf, fsdp_buf[0], MAXLONGFIELDLEN-1);
            if (NULL == media->unidentified_attributes)
            {
              media->unidentified_attributes_count = 0;
              media->unidentified_attributes =
                calloc (UNIDENTIFIED_ATTRIBUTES_MAX_COUNT,
                        sizeof (char *));
            }
            if (media->unidentified_attributes_count <
                UNIDENTIFIED_ATTRIBUTES_MAX_COUNT)
            {
              media->unidentified_attributes
                [media->unidentified_attributes_count] =
                strdup (longfsdp_buf);
              media->unidentified_attributes_count++;
            }
          }
          NEXT_LINE (p);
        }
        else
          return FSDPE_INVALID_ATTRIBUTE;
      }
    }			/* end of for */
  }

  /* Check c= has been given at session level or at media level for
     all media */
  if (NULL == dsc->c_address.address)
  {
    unsigned int c;
    for (c = 0; c < dsc->media_announcements_count; c++)
      if (NULL == dsc->media_announcements[c]->c_address.address)
        return FSDPE_MISSING_CONNECTION_INFO;
  }

  /* finish */
  if (*p == '\0')
    return FSDPE_OK;
  else
    return FSDPE_OVERFILLED;
}

static fsdp_error_t
fsdp_parse_c (const char **p, fsdp_network_type_t * ntype,
	      fsdp_address_type_t * atype,
	      fsdp_connection_address_t * address)
{
  const unsigned int TEMPCHARS = 3;
  char fsdp_buf[TEMPCHARS][MAXSHORTFIELDLEN];

  if (!strncmp (*p, "c=", 2))
  {
    if (sscanf (*p, "c=%2s %3s %" MSFLENS "s",
                fsdp_buf[0], fsdp_buf[1], fsdp_buf[2]))
    {
      if (!strncmp (fsdp_buf[0], "IN", 2))
      {
        *ntype = FSDP_NETWORK_TYPE_INET;
        if (!strncmp (fsdp_buf[1], "IP4", 3))
          *atype = FSDP_ADDRESS_TYPE_IPV4;
        else if (!strncmp (fsdp_buf[1], "IP6", 3))
          *atype = FSDP_ADDRESS_TYPE_IPV6;
        else
          return FSDPE_INVALID_CONNECTION_NETTYPE;
      }
      else
      {
        return FSDPE_INVALID_CONNECTION_ADDRTYPE;
      }
      {
        char *slash = strchr (fsdp_buf[2], '/');
        if (NULL == slash)
        {
          address->address = strdup (fsdp_buf[2]);
          address->address_ttl = 0;
          address->address_count = 0;
        }
        else
        {
          /* address is IP4 multicast */
          char *slash2;
          *slash = '\0';
          slash++;
          address->address = strdup (fsdp_buf[2]);
          slash2 = strchr (slash + 1, '/');
          if (NULL == slash2)
          {
            address->address_ttl = strtol (slash, NULL, 10);
            address->address_count = 0;
          }
          else
          {
            *slash2 = '\0';
            slash2++;
            address->address_ttl = strtol (slash, NULL, 10);
            address->address_count = strtol (slash2, NULL, 10);
          }
        }
      }
      NEXT_LINE (*p);
    }
    else
    {
      return FSDPE_INVALID_CONNECTION;
    }
  }
  return FSDPE_OK;
}

static fsdp_error_t