00001 /* 00002 * Session Announcement Protocol (RFC 2974) demuxer 00003 * Copyright (c) 2010 Martin Storsjo 00004 * 00005 * This file is part of FFmpeg. 00006 * 00007 * FFmpeg is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * FFmpeg is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with FFmpeg; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00022 #include "avformat.h" 00023 #include "libavutil/avstring.h" 00024 #include "libavutil/intreadwrite.h" 00025 #include "network.h" 00026 #include "os_support.h" 00027 #include "internal.h" 00028 #include "avio_internal.h" 00029 #include "url.h" 00030 #if HAVE_POLL_H 00031 #include <poll.h> 00032 #endif 00033 #include <sys/time.h> 00034 00035 struct SAPState { 00036 URLContext *ann_fd; 00037 AVFormatContext *sdp_ctx; 00038 AVIOContext sdp_pb; 00039 uint16_t hash; 00040 char *sdp; 00041 int eof; 00042 }; 00043 00044 static int sap_probe(AVProbeData *p) 00045 { 00046 if (av_strstart(p->filename, "sap:", NULL)) 00047 return AVPROBE_SCORE_MAX; 00048 return 0; 00049 } 00050 00051 static int sap_read_close(AVFormatContext *s) 00052 { 00053 struct SAPState *sap = s->priv_data; 00054 if (sap->sdp_ctx) 00055 avformat_close_input(&sap->sdp_ctx); 00056 if (sap->ann_fd) 00057 ffurl_close(sap->ann_fd); 00058 av_freep(&sap->sdp); 00059 ff_network_close(); 00060 return 0; 00061 } 00062 00063 static int sap_read_header(AVFormatContext *s, 00064 AVFormatParameters *ap) 00065 { 00066 struct SAPState *sap = s->priv_data; 00067 char host[1024], path[1024], url[1024]; 00068 uint8_t recvbuf[1500]; 00069 int port; 00070 int ret, i; 00071 AVInputFormat* infmt; 00072 00073 if (!ff_network_init()) 00074 return AVERROR(EIO); 00075 00076 av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port, 00077 path, sizeof(path), s->filename); 00078 if (port < 0) 00079 port = 9875; 00080 00081 if (!host[0]) { 00082 /* Listen for announcements on sap.mcast.net if no host was specified */ 00083 av_strlcpy(host, "224.2.127.254", sizeof(host)); 00084 } 00085 00086 ff_url_join(url, sizeof(url), "udp", NULL, host, port, "?localport=%d", 00087 port); 00088 ret = ffurl_open(&sap->ann_fd, url, AVIO_FLAG_READ, 00089 &s->interrupt_callback, NULL); 00090 if (ret) 00091 goto fail; 00092 00093 while (1) { 00094 int addr_type, auth_len; 00095 int pos; 00096 00097 ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf) - 1); 00098 if (ret == AVERROR(EAGAIN)) 00099 continue; 00100 if (ret < 0) 00101 goto fail; 00102 recvbuf[ret] = '0円'; /* Null terminate for easier parsing */ 00103 if (ret < 8) { 00104 av_log(s, AV_LOG_WARNING, "Received too short packet\n"); 00105 continue; 00106 } 00107 00108 if ((recvbuf[0] & 0xe0) != 0x20) { 00109 av_log(s, AV_LOG_WARNING, "Unsupported SAP version packet " 00110 "received\n"); 00111 continue; 00112 } 00113 00114 if (recvbuf[0] & 0x04) { 00115 av_log(s, AV_LOG_WARNING, "Received stream deletion " 00116 "announcement\n"); 00117 continue; 00118 } 00119 addr_type = recvbuf[0] & 0x10; 00120 auth_len = recvbuf[1]; 00121 sap->hash = AV_RB16(&recvbuf[2]); 00122 pos = 4; 00123 if (addr_type) 00124 pos += 16; /* IPv6 */ 00125 else 00126 pos += 4; /* IPv4 */ 00127 pos += auth_len * 4; 00128 if (pos + 4 >= ret) { 00129 av_log(s, AV_LOG_WARNING, "Received too short packet\n"); 00130 continue; 00131 } 00132 #define MIME "application/sdp" 00133 if (strcmp(&recvbuf[pos], MIME) == 0) { 00134 pos += strlen(MIME) + 1; 00135 } else if (strncmp(&recvbuf[pos], "v=0\r\n", 5) == 0) { 00136 // Direct SDP without a mime type 00137 } else { 00138 av_log(s, AV_LOG_WARNING, "Unsupported mime type %s\n", 00139 &recvbuf[pos]); 00140 continue; 00141 } 00142 00143 sap->sdp = av_strdup(&recvbuf[pos]); 00144 break; 00145 } 00146 00147 av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sap->sdp); 00148 ffio_init_context(&sap->sdp_pb, sap->sdp, strlen(sap->sdp), 0, NULL, NULL, 00149 NULL, NULL); 00150 00151 infmt = av_find_input_format("sdp"); 00152 if (!infmt) 00153 goto fail; 00154 sap->sdp_ctx = avformat_alloc_context(); 00155 if (!sap->sdp_ctx) { 00156 ret = AVERROR(ENOMEM); 00157 goto fail; 00158 } 00159 sap->sdp_ctx->max_delay = s->max_delay; 00160 sap->sdp_ctx->pb = &sap->sdp_pb; 00161 sap->sdp_ctx->interrupt_callback = s->interrupt_callback; 00162 ret = avformat_open_input(&sap->sdp_ctx, "temp.sdp", infmt, NULL); 00163 if (ret < 0) 00164 goto fail; 00165 if (sap->sdp_ctx->ctx_flags & AVFMTCTX_NOHEADER) 00166 s->ctx_flags |= AVFMTCTX_NOHEADER; 00167 for (i = 0; i < sap->sdp_ctx->nb_streams; i++) { 00168 AVStream *st = avformat_new_stream(s, NULL); 00169 if (!st) { 00170 ret = AVERROR(ENOMEM); 00171 goto fail; 00172 } 00173 st->id = i; 00174 avcodec_copy_context(st->codec, sap->sdp_ctx->streams[i]->codec); 00175 st->time_base = sap->sdp_ctx->streams[i]->time_base; 00176 } 00177 00178 return 0; 00179 00180 fail: 00181 sap_read_close(s); 00182 return ret; 00183 } 00184 00185 static int sap_fetch_packet(AVFormatContext *s, AVPacket *pkt) 00186 { 00187 struct SAPState *sap = s->priv_data; 00188 int fd = ffurl_get_file_handle(sap->ann_fd); 00189 int n, ret; 00190 struct pollfd p = {fd, POLLIN, 0}; 00191 uint8_t recvbuf[1500]; 00192 00193 if (sap->eof) 00194 return AVERROR_EOF; 00195 00196 while (1) { 00197 n = poll(&p, 1, 0); 00198 if (n <= 0 || !(p.revents & POLLIN)) 00199 break; 00200 ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf)); 00201 if (ret >= 8) { 00202 uint16_t hash = AV_RB16(&recvbuf[2]); 00203 /* Should ideally check the source IP address, too */ 00204 if (recvbuf[0] & 0x04 && hash == sap->hash) { 00205 /* Stream deletion */ 00206 sap->eof = 1; 00207 return AVERROR_EOF; 00208 } 00209 } 00210 } 00211 ret = av_read_frame(sap->sdp_ctx, pkt); 00212 if (ret < 0) 00213 return ret; 00214 if (s->ctx_flags & AVFMTCTX_NOHEADER) { 00215 while (sap->sdp_ctx->nb_streams > s->nb_streams) { 00216 int i = s->nb_streams; 00217 AVStream *st = avformat_new_stream(s, NULL); 00218 if (!st) { 00219 av_free_packet(pkt); 00220 return AVERROR(ENOMEM); 00221 } 00222 st->id = i; 00223 avcodec_copy_context(st->codec, sap->sdp_ctx->streams[i]->codec); 00224 st->time_base = sap->sdp_ctx->streams[i]->time_base; 00225 } 00226 } 00227 return ret; 00228 } 00229 00230 AVInputFormat ff_sap_demuxer = { 00231 .name = "sap", 00232 .long_name = NULL_IF_CONFIG_SMALL("SAP input format"), 00233 .priv_data_size = sizeof(struct SAPState), 00234 .read_probe = sap_probe, 00235 .read_header = sap_read_header, 00236 .read_packet = sap_fetch_packet, 00237 .read_close = sap_read_close, 00238 .flags = AVFMT_NOFILE, 00239 }; 00240