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1 | #include <stdio.h> | |
2 | #include <stdlib.h> | |
3 | #include <sys/types.h> | |
4 | #include <sys/socket.h> | |
5 | #include <netinet/in.h> | |
6 | #include <arpa/inet.h> | |
7 | #include <sys/time.h> | |
8 | #include <time.h> | |
9 | #include <string.h> | |
10 | #include <strings.h> | |
11 | #include <unistd.h> | |
12 | #include <sys/select.h> | |
13 | ||
14 | #include "mcast.h" | |
15 | #include "sap.h" | |
16 | ||
17 | #define SAP_ADDR "224.2.127.254" | |
18 | #define SAP_PORT 9875 | |
19 | #define SAP_MAX_SIZE 1024 | |
20 | ||
21 | #define SAP_TIMEOUT 3 | |
22 | ||
23 | #define BUFFSIZE SAP_MAX_SIZE | |
24 | ||
25 | struct sdp_info { | |
26 | char *service; | |
27 | char *host; | |
28 | char *proto; | |
29 | char *port; | |
30 | }; | |
31 | ||
32 | struct sdp_info *parse_sdp(char *sdp, int len) | |
33 | { | |
34 | char *pos, *line; | |
35 | static struct sdp_info sdpinfo; | |
36 | ||
37 | /* RFC 2327 | |
38 | * v=0 | |
39 | * o=- 6dca 1 IN IP4 192.168.100.17:2000 | |
40 | * s=TV Das Erste | |
41 | * t=0 0 | |
42 | * c=IN IP4 192.168.100.17/1 | |
43 | * m=video 2000 http 33 | |
44 | * a=tool:getstream | |
45 | * a=type:broadcast | |
46 | */ | |
47 | ||
48 | bzero(&sdpinfo, sizeof(struct sdp_info)); | |
49 | ||
50 | pos = line = sdp; | |
51 | while(*pos != 0 && (pos-sdp) < len) { | |
52 | if (*pos == 0x0d) | |
53 | *pos = 0; | |
54 | ||
55 | if (*pos == 0x0a) { | |
56 | *pos = 0; | |
57 | ||
58 | if (!strncasecmp("s=", line, 2)) { | |
59 | sdpinfo.service = line + 2; | |
60 | } else if (!strncasecmp("c=", line, 2)) { | |
61 | int poscnt = 0; | |
62 | ||
63 | line += 2; | |
64 | while (*line != 0) { | |
65 | if (poscnt == 2 && *line == '/') { | |
66 | *line = 0; | |
67 | break; | |
68 | } | |
69 | ||
70 | if (*line == ' ') { | |
71 | *line = 0; | |
72 | poscnt++; | |
73 | ||
74 | /* c=<network type> <address type> <connection address> */ | |
75 | if (poscnt == 2) | |
76 | sdpinfo.host = line + 1; | |
77 | ||
78 | if (poscnt > 2) | |
79 | break; | |
80 | } | |
81 | line++; | |
82 | } | |
83 | } else if (!strncasecmp("m=", line, 2)) { | |
84 | int poscnt = 0; | |
85 | ||
86 | line += 2; | |
87 | while (*line != 0) { | |
88 | if (*line == ' ') { | |
89 | *line = 0; | |
90 | poscnt++; | |
91 | ||
92 | /* m=<media> <port> <transport> <fmt list> */ | |
93 | if (poscnt == 1) | |
94 | sdpinfo.port = line + 1; | |
95 | ||
96 | if (poscnt == 2) | |
97 | sdpinfo.proto = line + 1; | |
98 | ||
99 | if (poscnt > 2) | |
100 | break; | |
101 | } | |
102 | line++; | |
103 | } | |
104 | } | |
105 | ||
106 | line = ++pos; | |
107 | continue; | |
108 | } | |
109 | pos++; | |
110 | } | |
111 | ||
112 | return &sdpinfo; | |
113 | } | |
114 | ||
115 | ||
116 | char *get_url_from_sap(char *service) | |
117 | { | |
118 | struct timeval start, curr; | |
119 | struct ip_mreq mreq; | |
120 | unsigned char buffer[BUFFSIZE]; | |
121 | struct in_addr sapinaddr; | |
122 | char *url = NULL; | |
123 | int fd; | |
124 | ||
125 | snprintf(buffer,BUFFSIZE,"udp://%s:%u", SAP_ADDR, SAP_PORT); | |
126 | ||
127 | fd = open_mcast(buffer); | |
128 | ||
129 | gettimeofday(&start, NULL); | |
130 | ||
131 | do { | |
132 | int recvd; | |
133 | fd_set rfds; | |
134 | struct timeval tv; | |
135 | int retval; | |
136 | int sap_version, sap_addrtype, sap_messagetype, sap_encrypted, sap_compressed; | |
137 | uint8_t sender_address[16]; /* This might be IPv6! */ | |
138 | unsigned char auth_len; | |
139 | unsigned short msgid; | |
140 | unsigned char *sdp; | |
141 | struct sdp_info *sdpinfo; | |
142 | ||
143 | FD_ZERO(&rfds); | |
144 | FD_SET(fd, &rfds); | |
145 | ||
146 | tv.tv_sec = 0; | |
147 | tv.tv_usec = 100000; | |
148 | ||
149 | if ((retval = select(fd+1, &rfds, NULL, NULL, &tv)) == -1) { | |
150 | perror("select"); | |
151 | break; | |
152 | } | |
153 | ||
154 | if (!retval) { | |
155 | gettimeofday(&curr, NULL); | |
156 | continue; | |
157 | } | |
158 | ||
159 | bzero(buffer, BUFFSIZE); | |
160 | if ((recvd = recv(fd, buffer, BUFFSIZE, 0)) < 1) { | |
161 | perror("recv"); | |
162 | break; | |
163 | } | |
164 | ||
165 | gettimeofday(&curr, NULL); | |
166 | ||
167 | sap_version = (buffer[0] >> 5) & 0x7; | |
168 | sap_addrtype = (buffer[0] >> 4) & 0x1; | |
169 | sap_messagetype = (buffer[0] >> 2) & 0x1; | |
170 | sap_encrypted = (buffer[0] >> 1) & 0x1; | |
171 | sap_compressed = buffer[0] & 0x1; | |
172 | auth_len = buffer[1]; | |
173 | msgid = buffer[2] << 8 | buffer[3]; | |
174 | memcpy(sender_address, buffer+4, (sap_addrtype?16:4)); | |
175 | sdp = buffer + 4 /* (sap_*, auth_len, msgid) */ + (sap_addrtype?16:4) + auth_len; | |
176 | ||
177 | #ifdef DEBUG | |
178 | printf("\n"); | |
179 | printf("SAP-Version: %d\n", sap_version); | |
180 | printf("Adresstyp: %s\n", (sap_addrtype?"IPv6":"IPv4")); | |
181 | printf("Messagetype: %s\n", (sap_messagetype?"Announcement":"Deletion")); | |
182 | printf("Encrypted: %d\n", sap_encrypted); | |
183 | printf("Compressed: %d\n", sap_compressed); | |
184 | printf("Authentication Length: %d\n", auth_len); | |
185 | printf("Sender: %u\n", *((in_addr_t*)sender_address)); | |
186 | printf("Message Identifier Hash: %u\n", msgid); | |
187 | #endif | |
188 | ||
189 | #if 0 /* Getstream gets this wrong, see rfc2974 */ | |
190 | if (sap_messagetype) | |
191 | continue; /* We are not interested in deletions */ | |
192 | #endif | |
193 | ||
194 | if (sap_encrypted || sap_compressed) | |
195 | continue; | |
196 | ||
197 | sdpinfo = parse_sdp(sdp, recvd-(sdp-buffer)); | |
198 | ||
199 | if (sdpinfo->service && sdpinfo->proto && sdpinfo->port) { | |
200 | char hostbuf[INET6_ADDRSTRLEN]; | |
201 | ||
202 | if (!sdpinfo->host) { | |
203 | ||
204 | if (sap_addrtype) { | |
205 | struct in6_addr in6addr; | |
206 | ||
207 | memcpy(in6addr.in6_u.u6_addr8, sender_address, 16); | |
208 | if (!(sdpinfo->host = (char*)inet_ntop(AF_INET6, &in6addr, hostbuf, INET6_ADDRSTRLEN))) { | |
209 | perror("inet_ntop"); | |
210 | continue; | |
211 | } | |
212 | } else { | |
213 | struct in_addr inaddr; | |
214 | ||
215 | inaddr.s_addr = *((in_addr_t*)sender_address); | |
216 | if (!(sdpinfo->host = (char*)inet_ntop(AF_INET, &inaddr, hostbuf, INET6_ADDRSTRLEN))) { | |
217 | perror("inet_ntop"); | |
218 | continue; | |
219 | } | |
220 | } | |
221 | } | |
222 | ||
223 | #ifdef DEBUG | |
224 | printf("%s -> %s://%s:%s\n", sdpinfo->service, sdpinfo->proto, sdpinfo->host, sdpinfo->port); | |
225 | #endif | |
226 | ||
227 | if (strlen(service) < strlen(sdpinfo->service)) { | |
228 | sdpinfo->service += strlen(sdpinfo->service) - strlen(service); | |
229 | } | |
230 | ||
231 | if (!strncasecmp(service, sdpinfo->service, strlen(service))) { | |
232 | int len = strlen(sdpinfo->host)+strlen(sdpinfo->proto)+strlen(sdpinfo->port)+5; | |
233 | ||
234 | if (!(url = malloc(len))) { | |
235 | perror("malloc"); | |
236 | break; | |
237 | } | |
238 | ||
239 | snprintf(url, len, "%s://%s:%s", sdpinfo->proto, sdpinfo->host, sdpinfo->port); | |
240 | url[len-1] = 0; | |
241 | break; | |
242 | } | |
243 | } | |
244 | ||
245 | } while(curr.tv_sec < start.tv_sec+SAP_TIMEOUT || | |
246 | ((curr.tv_sec == start.tv_sec+SAP_TIMEOUT) && (curr.tv_usec < start.tv_usec))); | |
247 | ||
248 | if (!(inet_aton(SAP_ADDR, &sapinaddr))) { | |
249 | perror("inet_aton"); | |
250 | } | |
251 | ||
252 | mreq.imr_multiaddr.s_addr = sapinaddr.s_addr; | |
253 | mreq.imr_interface.s_addr = INADDR_ANY; | |
254 | setsockopt (fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq, sizeof(mreq)); | |
255 | ||
256 | close(fd); | |
257 | ||
258 | return url; | |
259 | } |