21f893554f3d85d7d5297aa05db92785b729c6a4
[libav.git] / libavformat / sapdec.c
1 /*
2 * Session Announcement Protocol (RFC 2974) demuxer
3 * Copyright (c) 2010 Martin Storsjo
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; 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 #if HAVE_POLL_H
31 #include <poll.h>
32 #endif
33 #include <sys/time.h>
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 av_close_input_file(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 AVFormatParameters *ap)
65 {
66 struct SAPState *sap = s->priv_data;
67 char host[1024], path[1024], url[1024];
68 uint8_t recvbuf[1500];
69 int port;
70 int ret, i;
71 AVInputFormat* infmt;
72
73 if (!ff_network_init())
74 return AVERROR(EIO);
75
76 av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port,
77 path, sizeof(path), s->filename);
78 if (port < 0)
79 port = 9875;
80
81 if (!host[0]) {
82 /* Listen for announcements on sap.mcast.net if no host was specified */
83 av_strlcpy(host, "224.2.127.254", sizeof(host));
84 }
85
86 ff_url_join(url, sizeof(url), "udp", NULL, host, port, "?localport=%d",
87 port);
88 ret = ffurl_open(&sap->ann_fd, url, AVIO_FLAG_READ, &s->interrupt_callback);
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 ret = avformat_open_input(&sap->sdp_ctx, "temp.sdp", infmt, NULL);
161 if (ret < 0)
162 goto fail;
163 if (sap->sdp_ctx->ctx_flags & AVFMTCTX_NOHEADER)
164 s->ctx_flags |= AVFMTCTX_NOHEADER;
165 for (i = 0; i < sap->sdp_ctx->nb_streams; i++) {
166 AVStream *st = avformat_new_stream(s, NULL);
167 if (!st) {
168 ret = AVERROR(ENOMEM);
169 goto fail;
170 }
171 st->id = i;
172 avcodec_copy_context(st->codec, sap->sdp_ctx->streams[i]->codec);
173 st->time_base = sap->sdp_ctx->streams[i]->time_base;
174 }
175
176 return 0;
177
178 fail:
179 sap_read_close(s);
180 return ret;
181 }
182
183 static int sap_fetch_packet(AVFormatContext *s, AVPacket *pkt)
184 {
185 struct SAPState *sap = s->priv_data;
186 int fd = ffurl_get_file_handle(sap->ann_fd);
187 int n, ret;
188 struct pollfd p = {fd, POLLIN, 0};
189 uint8_t recvbuf[1500];
190
191 if (sap->eof)
192 return AVERROR_EOF;
193
194 while (1) {
195 n = poll(&p, 1, 0);
196 if (n <= 0 || !(p.revents & POLLIN))
197 break;
198 ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf));
199 if (ret >= 8) {
200 uint16_t hash = AV_RB16(&recvbuf[2]);
201 /* Should ideally check the source IP address, too */
202 if (recvbuf[0] & 0x04 && hash == sap->hash) {
203 /* Stream deletion */
204 sap->eof = 1;
205 return AVERROR_EOF;
206 }
207 }
208 }
209 ret = av_read_frame(sap->sdp_ctx, pkt);
210 if (ret < 0)
211 return ret;
212 if (s->ctx_flags & AVFMTCTX_NOHEADER) {
213 while (sap->sdp_ctx->nb_streams > s->nb_streams) {
214 int i = s->nb_streams;
215 AVStream *st = avformat_new_stream(s, NULL);
216 if (!st) {
217 av_free_packet(pkt);
218 return AVERROR(ENOMEM);
219 }
220 st->id = i;
221 avcodec_copy_context(st->codec, sap->sdp_ctx->streams[i]->codec);
222 st->time_base = sap->sdp_ctx->streams[i]->time_base;
223 }
224 }
225 return ret;
226 }
227
228 AVInputFormat ff_sap_demuxer = {
229 .name = "sap",
230 .long_name = NULL_IF_CONFIG_SMALL("SAP input format"),
231 .priv_data_size = sizeof(struct SAPState),
232 .read_probe = sap_probe,
233 .read_header = sap_read_header,
234 .read_packet = sap_fetch_packet,
235 .read_close = sap_read_close,
236 .flags = AVFMT_NOFILE,
237 };
238