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1 /***
2   This file is part of PulseAudio.
3 
4   Copyright 2006 Lennart Poettering
5 
6   PulseAudio is free software; you can redistribute it and/or modify
7   it under the terms of the GNU Lesser General Public License as published
8   by the Free Software Foundation; either version 2.1 of the License,
9   or (at your option) any later version.
10 
11   PulseAudio is distributed in the hope that it will be useful, but
12   WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14   General Public License for more details.
15 
16   You should have received a copy of the GNU Lesser General Public License
17   along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
18 ***/
19 
20 #ifdef HAVE_CONFIG_H
21 #include <config.h>
22 #endif
23 
24 #include <time.h>
25 #include <stdlib.h>
26 #include <sys/types.h>
27 #include <sys/socket.h>
28 #include <netinet/in.h>
29 #include <string.h>
30 
31 #include <pulse/xmalloc.h>
32 #include <pulse/util.h>
33 
34 #include <pulsecore/core-util.h>
35 #include <pulsecore/log.h>
36 #include <pulsecore/macro.h>
37 #include <pulsecore/arpa-inet.h>
38 
39 #include "sdp.h"
40 #include "rtp.h"
41 
pa_sdp_build(int af,const void * src,const void * dst,const char * name,uint16_t port,uint8_t payload,const pa_sample_spec * ss,bool enable_opus)42 char *pa_sdp_build(int af, const void *src, const void *dst, const char *name, uint16_t port, uint8_t payload, const pa_sample_spec *ss, bool enable_opus) {
43     uint32_t ntp;
44     uint32_t rate, channels;
45     char buf_src[64], buf_dst[64], un[64];
46     const char *u, *f;
47 
48     pa_assert(src);
49     pa_assert(dst);
50 
51 #ifdef HAVE_IPV6
52     pa_assert(af == AF_INET || af == AF_INET6);
53 #else
54     pa_assert(af == AF_INET);
55 #endif
56 
57     if (enable_opus) {
58         f = "OPUS";
59         rate = 48000;
60         channels = 2;
61     } else {
62         pa_assert_se(f = pa_rtp_format_to_string(ss->format));
63         rate = ss->rate;
64         channels = ss->channels;
65     }
66 
67     if (!(u = pa_get_user_name(un, sizeof(un))))
68         u = "-";
69 
70     ntp = (uint32_t) time(NULL) + 2208988800U;
71 
72     pa_assert_se(inet_ntop(af, src, buf_src, sizeof(buf_src)));
73     pa_assert_se(inet_ntop(af, dst, buf_dst, sizeof(buf_dst)));
74 
75     return pa_sprintf_malloc(
76             PA_SDP_HEADER
77             "o=%s %lu 0 IN %s %s\n"
78             "s=%s\n"
79             "c=IN %s %s\n"
80             "t=%lu 0\n"
81             "a=recvonly\n"
82             "m=audio %u RTP/AVP %i\n"
83             "a=rtpmap:%i %s/%u/%u\n"
84             "a=type:broadcast\n",
85             u, (unsigned long) ntp, af == AF_INET ? "IP4" : "IP6", buf_src,
86             name,
87             af == AF_INET ? "IP4" : "IP6", buf_dst,
88             (unsigned long) ntp,
89             port, payload,
90             payload, f, rate, channels);
91 }
92 
parse_sdp_sample_spec(pa_sample_spec * ss,char * c)93 static pa_sample_spec *parse_sdp_sample_spec(pa_sample_spec *ss, char *c) {
94     unsigned rate, channels;
95     pa_assert(ss);
96     pa_assert(c);
97 
98     if (pa_startswith(c, "L16/")) {
99         ss->format = PA_SAMPLE_S16BE;
100         c += 4;
101     } else if (pa_startswith(c, "OPUS/")) {
102         ss->format = PA_SAMPLE_S16LE;
103         c += 5;
104     } else
105         return NULL;
106 
107     if (sscanf(c, "%u/%u", &rate, &channels) == 2) {
108         ss->rate = (uint32_t) rate;
109         ss->channels = (uint8_t) channels;
110     } else if (sscanf(c, "%u", &rate) == 2) {
111         ss->rate = (uint32_t) rate;
112         ss->channels = 1;
113     } else
114         return NULL;
115 
116     if (!pa_sample_spec_valid(ss))
117         return NULL;
118 
119     return ss;
120 }
121 
pa_sdp_parse(const char * t,pa_sdp_info * i,int is_goodbye)122 pa_sdp_info *pa_sdp_parse(const char *t, pa_sdp_info *i, int is_goodbye) {
123     uint16_t port = 0;
124     bool ss_valid = false;
125 
126     pa_assert(t);
127     pa_assert(i);
128 
129     i->origin = i->session_name = NULL;
130     i->salen = 0;
131     i->payload = 255;
132     i->enable_opus = false;
133 
134     if (!pa_startswith(t, PA_SDP_HEADER)) {
135         pa_log("Failed to parse SDP data: invalid header.");
136         goto fail;
137     }
138 
139     t += sizeof(PA_SDP_HEADER)-1;
140 
141     while (*t) {
142         size_t l;
143 
144         l = strcspn(t, "\n");
145 
146         if (l <= 2) {
147             pa_log("Failed to parse SDP data: line too short: >%s<.", t);
148             goto fail;
149         }
150 
151         if (pa_startswith(t, "o="))
152             i->origin = pa_xstrndup(t+2, l-2);
153         else if (pa_startswith(t, "s="))
154             i->session_name = pa_xstrndup(t+2, l-2);
155         else if (pa_startswith(t, "c=IN IP4 ")) {
156             char a[64];
157             size_t k;
158 
159             k = l-8 > sizeof(a) ? sizeof(a) : l-8;
160 
161             pa_strlcpy(a, t+9, k);
162             a[strcspn(a, "/")] = 0;
163 
164             if (inet_pton(AF_INET, a, &((struct sockaddr_in*) &i->sa)->sin_addr) <= 0) {
165                 pa_log("Failed to parse SDP data: bad address: >%s<.", a);
166                 goto fail;
167             }
168 
169             ((struct sockaddr_in*) &i->sa)->sin_family = AF_INET;
170             ((struct sockaddr_in*) &i->sa)->sin_port = 0;
171             i->salen = sizeof(struct sockaddr_in);
172 #ifdef HAVE_IPV6
173         } else if (pa_startswith(t, "c=IN IP6 ")) {
174             char a[64];
175             size_t k;
176 
177             k = l-8 > sizeof(a) ? sizeof(a) : l-8;
178 
179             pa_strlcpy(a, t+9, k);
180             a[strcspn(a, "/")] = 0;
181 
182             if (inet_pton(AF_INET6, a, &((struct sockaddr_in6*) &i->sa)->sin6_addr) <= 0) {
183                 pa_log("Failed to parse SDP data: bad address: >%s<.", a);
184                 goto fail;
185             }
186 
187             ((struct sockaddr_in6*) &i->sa)->sin6_family = AF_INET6;
188             ((struct sockaddr_in6*) &i->sa)->sin6_port = 0;
189             i->salen = sizeof(struct sockaddr_in6);
190 #endif
191         } else if (pa_startswith(t, "m=audio ")) {
192 
193             if (i->payload > 127) {
194                 int _port, _payload;
195 
196                 if (sscanf(t+8, "%i RTP/AVP %i", &_port, &_payload) == 2) {
197 
198                     if (_port <= 0 || _port > 0xFFFF) {
199                         pa_log("Failed to parse SDP data: invalid port %i.", _port);
200                         goto fail;
201                     }
202 
203                     if (_payload < 0 || _payload > 127) {
204                         pa_log("Failed to parse SDP data: invalid payload %i.", _payload);
205                         goto fail;
206                     }
207 
208                     port = (uint16_t) _port;
209                     i->payload = (uint8_t) _payload;
210 
211                     if (pa_rtp_sample_spec_from_payload(i->payload, &i->sample_spec))
212                         ss_valid = true;
213                 }
214             }
215         } else if (pa_startswith(t, "a=rtpmap:")) {
216 
217             if (i->payload <= 127) {
218                 char c[64];
219                 int _payload;
220                 int len;
221 
222                 if (sscanf(t + 9, "%i %n", &_payload, &len) == 1) {
223                     if (_payload < 0 || _payload > 127) {
224                         pa_log("Failed to parse SDP data: invalid payload %i.", _payload);
225                         goto fail;
226                     }
227                     if (_payload == i->payload) {
228                         strncpy(c, t + 9 + len, 63);
229                         c[63] = 0;
230                         c[strcspn(c, "\n")] = 0;
231 
232                         if (parse_sdp_sample_spec(&i->sample_spec, c))
233                             ss_valid = true;
234 
235                         if (pa_startswith(c, "OPUS/"))
236                             i->enable_opus = true;
237                     }
238                 }
239             }
240         }
241 
242         t += l;
243 
244         if (*t == '\n')
245             t++;
246     }
247 
248     if (!i->origin || (!is_goodbye && (!i->salen || i->payload > 127 || !ss_valid || port == 0))) {
249         pa_log("Failed to parse SDP data: missing data.");
250         goto fail;
251     }
252 
253     if (((struct sockaddr*) &i->sa)->sa_family == AF_INET)
254         ((struct sockaddr_in*) &i->sa)->sin_port = htons(port);
255     else
256         ((struct sockaddr_in6*) &i->sa)->sin6_port = htons(port);
257 
258     return i;
259 
260 fail:
261     pa_xfree(i->origin);
262     pa_xfree(i->session_name);
263 
264     return NULL;
265 }
266 
pa_sdp_info_destroy(pa_sdp_info * i)267 void pa_sdp_info_destroy(pa_sdp_info *i) {
268     pa_assert(i);
269 
270     pa_xfree(i->origin);
271     pa_xfree(i->session_name);
272 }
273