Subversion Repositories Kolibri OS

Rev

Go to most recent revision | Blame | Last modification | View Log | RSS feed

  1. /*
  2.  * Session Announcement Protocol (RFC 2974) demuxer
  3.  * Copyright (c) 2010 Martin Storsjo
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg is free software; you can redistribute it and/or
  8.  * modify it under the terms of the GNU Lesser General Public
  9.  * License as published by the Free Software Foundation; either
  10.  * version 2.1 of the License, or (at your option) any later version.
  11.  *
  12.  * FFmpeg is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15.  * Lesser General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU Lesser General Public
  18.  * License along with FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20.  */
  21.  
  22. #include "avformat.h"
  23. #include "libavutil/avstring.h"
  24. #include "libavutil/intreadwrite.h"
  25. #include "network.h"
  26. #include "os_support.h"
  27. #include "internal.h"
  28. #include "avio_internal.h"
  29. #include "url.h"
  30. #include "rtpdec.h"
  31. #if HAVE_POLL_H
  32. #include <poll.h>
  33. #endif
  34.  
  35. struct SAPState {
  36.     URLContext *ann_fd;
  37.     AVFormatContext *sdp_ctx;
  38.     AVIOContext sdp_pb;
  39.     uint16_t hash;
  40.     char *sdp;
  41.     int eof;
  42. };
  43.  
  44. static int sap_probe(AVProbeData *p)
  45. {
  46.     if (av_strstart(p->filename, "sap:", NULL))
  47.         return AVPROBE_SCORE_MAX;
  48.     return 0;
  49. }
  50.  
  51. static int sap_read_close(AVFormatContext *s)
  52. {
  53.     struct SAPState *sap = s->priv_data;
  54.     if (sap->sdp_ctx)
  55.         avformat_close_input(&sap->sdp_ctx);
  56.     if (sap->ann_fd)
  57.         ffurl_close(sap->ann_fd);
  58.     av_freep(&sap->sdp);
  59.     ff_network_close();
  60.     return 0;
  61. }
  62.  
  63. static int sap_read_header(AVFormatContext *s)
  64. {
  65.     struct SAPState *sap = s->priv_data;
  66.     char host[1024], path[1024], url[1024];
  67.     uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
  68.     int port;
  69.     int ret, i;
  70.     AVInputFormat* infmt;
  71.  
  72.     if (!ff_network_init())
  73.         return AVERROR(EIO);
  74.  
  75.     av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port,
  76.                  path, sizeof(path), s->filename);
  77.     if (port < 0)
  78.         port = 9875;
  79.  
  80.     if (!host[0]) {
  81.         /* Listen for announcements on sap.mcast.net if no host was specified */
  82.         av_strlcpy(host, "224.2.127.254", sizeof(host));
  83.     }
  84.  
  85.     ff_url_join(url, sizeof(url), "udp", NULL, host, port, "?localport=%d",
  86.                 port);
  87.     ret = ffurl_open(&sap->ann_fd, url, AVIO_FLAG_READ,
  88.                      &s->interrupt_callback, NULL);
  89.     if (ret)
  90.         goto fail;
  91.  
  92.     while (1) {
  93.         int addr_type, auth_len;
  94.         int pos;
  95.  
  96.         ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf) - 1);
  97.         if (ret == AVERROR(EAGAIN))
  98.             continue;
  99.         if (ret < 0)
  100.             goto fail;
  101.         recvbuf[ret] = '\0'; /* Null terminate for easier parsing */
  102.         if (ret < 8) {
  103.             av_log(s, AV_LOG_WARNING, "Received too short packet\n");
  104.             continue;
  105.         }
  106.  
  107.         if ((recvbuf[0] & 0xe0) != 0x20) {
  108.             av_log(s, AV_LOG_WARNING, "Unsupported SAP version packet "
  109.                                       "received\n");
  110.             continue;
  111.         }
  112.  
  113.         if (recvbuf[0] & 0x04) {
  114.             av_log(s, AV_LOG_WARNING, "Received stream deletion "
  115.                                       "announcement\n");
  116.             continue;
  117.         }
  118.         addr_type = recvbuf[0] & 0x10;
  119.         auth_len  = recvbuf[1];
  120.         sap->hash = AV_RB16(&recvbuf[2]);
  121.         pos = 4;
  122.         if (addr_type)
  123.             pos += 16; /* IPv6 */
  124.         else
  125.             pos += 4; /* IPv4 */
  126.         pos += auth_len * 4;
  127.         if (pos + 4 >= ret) {
  128.             av_log(s, AV_LOG_WARNING, "Received too short packet\n");
  129.             continue;
  130.         }
  131. #define MIME "application/sdp"
  132.         if (strcmp(&recvbuf[pos], MIME) == 0) {
  133.             pos += strlen(MIME) + 1;
  134.         } else if (strncmp(&recvbuf[pos], "v=0\r\n", 5) == 0) {
  135.             // Direct SDP without a mime type
  136.         } else {
  137.             av_log(s, AV_LOG_WARNING, "Unsupported mime type %s\n",
  138.                                       &recvbuf[pos]);
  139.             continue;
  140.         }
  141.  
  142.         sap->sdp = av_strdup(&recvbuf[pos]);
  143.         break;
  144.     }
  145.  
  146.     av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sap->sdp);
  147.     ffio_init_context(&sap->sdp_pb, sap->sdp, strlen(sap->sdp), 0, NULL, NULL,
  148.                   NULL, NULL);
  149.  
  150.     infmt = av_find_input_format("sdp");
  151.     if (!infmt)
  152.         goto fail;
  153.     sap->sdp_ctx = avformat_alloc_context();
  154.     if (!sap->sdp_ctx) {
  155.         ret = AVERROR(ENOMEM);
  156.         goto fail;
  157.     }
  158.     sap->sdp_ctx->max_delay = s->max_delay;
  159.     sap->sdp_ctx->pb        = &sap->sdp_pb;
  160.     sap->sdp_ctx->interrupt_callback = s->interrupt_callback;
  161.     ret = avformat_open_input(&sap->sdp_ctx, "temp.sdp", infmt, NULL);
  162.     if (ret < 0)
  163.         goto fail;
  164.     if (sap->sdp_ctx->ctx_flags & AVFMTCTX_NOHEADER)
  165.         s->ctx_flags |= AVFMTCTX_NOHEADER;
  166.     for (i = 0; i < sap->sdp_ctx->nb_streams; i++) {
  167.         AVStream *st = avformat_new_stream(s, NULL);
  168.         if (!st) {
  169.             ret = AVERROR(ENOMEM);
  170.             goto fail;
  171.         }
  172.         st->id = i;
  173.         avcodec_copy_context(st->codec, sap->sdp_ctx->streams[i]->codec);
  174.         st->time_base = sap->sdp_ctx->streams[i]->time_base;
  175.     }
  176.  
  177.     return 0;
  178.  
  179. fail:
  180.     sap_read_close(s);
  181.     return ret;
  182. }
  183.  
  184. static int sap_fetch_packet(AVFormatContext *s, AVPacket *pkt)
  185. {
  186.     struct SAPState *sap = s->priv_data;
  187.     int fd = ffurl_get_file_handle(sap->ann_fd);
  188.     int n, ret;
  189.     struct pollfd p = {fd, POLLIN, 0};
  190.     uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
  191.  
  192.     if (sap->eof)
  193.         return AVERROR_EOF;
  194.  
  195.     while (1) {
  196.         n = poll(&p, 1, 0);
  197.         if (n <= 0 || !(p.revents & POLLIN))
  198.             break;
  199.         ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf));
  200.         if (ret >= 8) {
  201.             uint16_t hash = AV_RB16(&recvbuf[2]);
  202.             /* Should ideally check the source IP address, too */
  203.             if (recvbuf[0] & 0x04 && hash == sap->hash) {
  204.                 /* Stream deletion */
  205.                 sap->eof = 1;
  206.                 return AVERROR_EOF;
  207.             }
  208.         }
  209.     }
  210.     ret = av_read_frame(sap->sdp_ctx, pkt);
  211.     if (ret < 0)
  212.         return ret;
  213.     if (s->ctx_flags & AVFMTCTX_NOHEADER) {
  214.         while (sap->sdp_ctx->nb_streams > s->nb_streams) {
  215.             int i = s->nb_streams;
  216.             AVStream *st = avformat_new_stream(s, NULL);
  217.             if (!st) {
  218.                 av_free_packet(pkt);
  219.                 return AVERROR(ENOMEM);
  220.             }
  221.             st->id = i;
  222.             avcodec_copy_context(st->codec, sap->sdp_ctx->streams[i]->codec);
  223.             st->time_base = sap->sdp_ctx->streams[i]->time_base;
  224.         }
  225.     }
  226.     return ret;
  227. }
  228.  
  229. AVInputFormat ff_sap_demuxer = {
  230.     .name           = "sap",
  231.     .long_name      = NULL_IF_CONFIG_SMALL("SAP input"),
  232.     .priv_data_size = sizeof(struct SAPState),
  233.     .read_probe     = sap_probe,
  234.     .read_header    = sap_read_header,
  235.     .read_packet    = sap_fetch_packet,
  236.     .read_close     = sap_read_close,
  237.     .flags          = AVFMT_NOFILE,
  238. };
  239.