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2ba45a60 DM |
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 | }; |