enforce timeouts
[record-dvb] / sap.c
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 char *get_url_from_sap(char *service)
26 {
27 struct timeval start, curr;
28 struct ip_mreq mreq;
29 unsigned char buffer[BUFFSIZE];
30 char *url = NULL;
31 int fd;
32
33 snprintf(buffer,BUFFSIZE,"udp://%s:%u", SAP_ADDR, SAP_PORT);
34
35 fd = open_mcast(buffer);
36
37 gettimeofday(&start, NULL);
38
39 do {
40 int recvd;
41 int sap_version, sap_addrtype, sap_messagetype, sap_encrypted, sap_compressed;
42 in_addr_t sender_address;
43 unsigned char auth_len;
44 unsigned short msgid;
45 unsigned char *payload, *pos, *host = NULL, *proto = NULL, *port = NULL, *sname = NULL;
46 fd_set rfds;
47 struct timeval tv;
48 int retval;
49
50 FD_ZERO(&rfds);
51 FD_SET(fd, &rfds);
52
53 tv.tv_sec = 0;
54 tv.tv_usec = 1000;
55
56 if ((retval = select(fd+1, &rfds, NULL, NULL, &tv)) == -1) {
57 perror("select");
58 return NULL;
59 }
60
61 if (!retval) {
62 gettimeofday(&curr, NULL);
63 continue;
64 }
65
66 if ((recvd = recv(fd, buffer, BUFFSIZE, 0)) < 1) {
67 perror("recv");
68 return NULL;
69 }
70
71 gettimeofday(&curr, NULL);
72
73 sap_version = (buffer[0] >> 5) & 0x7;
74 sap_addrtype = (buffer[0] >> 4) & 0x1;
75 sap_messagetype = (buffer[0] >> 2) & 0x1;
76 sap_encrypted = (buffer[0] >> 1) & 0x1;
77 sap_compressed = buffer[0] & 0x1;
78 auth_len = buffer[1];
79 msgid = buffer[2] << 8 | buffer[3];
80 memcpy(&sender_address, buffer+4, (sap_addrtype?16:4));
81 payload = buffer + 4 /* (sap_*, auth_len, msgid) */ + (sap_addrtype?16:4) + auth_len;
82
83 #ifdef DEBUG
84 printf("\n");
85 printf("SAP-Version: %d\n", sap_version);
86 printf("Adresstyp: %s\n", (sap_addrtype?"IPv6":"IPv4"));
87 printf("Messagetype: %s\n", (sap_messagetype?"Announcement":"Deletion"));
88 printf("Encrypted: %d\n", sap_encrypted);
89 printf("Compressed: %d\n", sap_compressed);
90 printf("Authentication Length: %d\n", auth_len);
91 printf("Sender: %u\n", sender_address);
92 printf("Message Identifier Hash: %u\n", msgid);
93 #endif
94
95 if (sap_addrtype)
96 continue; /* We don't support IPv6 for now */
97
98 #if 0 /* Getstream gets this wrong, see rfc2974 */
99 if (sap_messagetype)
100 continue; /* We are not interested in deletions */
101 #endif
102
103 if (sap_encrypted || sap_compressed)
104 continue;
105
106 /* RFC 2327
107 * v=0
108 * o=- 6dca 1 IN IP4 192.168.100.17:2000
109 * s=TV Das Erste
110 * t=0 0
111 * c=IN IP4 192.168.100.17/1
112 * m=video 2000 http 33
113 * a=tool:getstream
114 * a=type:broadcast
115 */
116
117 pos = payload;
118 while(*pos != 0 && (pos-buffer) < BUFFSIZE) {
119 if (*pos == 0x0d) {
120 *pos = 0;
121 }
122
123 if (*pos == 0x0a) {
124 *pos = 0;
125
126 if (!strncasecmp("s=", payload, 2)) {
127 sname = payload + 2;
128 } else if (!strncasecmp("c=", payload, 2)) {
129 int poscnt = 0;
130
131 payload += 2;
132 while (*payload != 0) {
133 if (poscnt == 2 && *payload == '/') {
134 *payload = 0;
135 break;
136 }
137
138 if (*payload == ' ') {
139 *payload = 0;
140 poscnt++;
141
142 /* c=<network type> <address type> <connection address> */
143 if (poscnt == 2) {
144 host = payload + 1;
145 }
146
147 if (poscnt > 2) {
148 break;
149 }
150 }
151 payload++;
152 }
153 } else if (!strncasecmp("m=", payload, 2)) {
154 int poscnt = 0;
155
156 payload += 2;
157 while (*payload != 0) {
158 if (*payload == ' ') {
159 *payload = 0;
160 poscnt++;
161
162 /* m=<media> <port> <transport> <fmt list> */
163 if (poscnt == 1) {
164 port = payload + 1;
165 }
166
167 if (poscnt == 2) {
168 proto = payload + 1;
169 }
170
171 if (poscnt > 2) {
172 break;
173 }
174 }
175 payload++;
176 }
177 }
178
179 payload = ++pos;
180 continue;
181 }
182 pos++;
183 }
184
185 if (sname && proto && port) {
186 if (!host) {
187 struct in_addr inaddr;
188
189 inaddr.s_addr = sender_address;
190 host = inet_ntoa(inaddr);
191 }
192
193 #ifdef DEBUG
194 printf("%s -> %s://%s:%s\n", sname, proto, host, port);
195 #endif
196
197 if (strlen(service) < strlen(sname)) {
198 sname += strlen(sname) - strlen(service);
199 }
200
201 if (!strncasecmp(service, sname, strlen(service))) {
202 int len = strlen(host)+strlen(proto)+strlen(port)+5;
203
204 if (!(url = malloc(len))) {
205 perror("malloc");
206 return NULL;
207 }
208
209 snprintf(url, len, "%s://%s:%s", proto, host, port);
210 url[len-1] = 0;
211 break;
212 }
213 }
214
215 } while(curr.tv_sec < start.tv_sec+SAP_TIMEOUT);
216
217 mreq.imr_multiaddr.s_addr = inet_addr(SAP_ADDR);
218 mreq.imr_interface.s_addr = INADDR_ANY;
219 setsockopt (fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq, sizeof(mreq));
220
221 close(fd);
222
223 return url;
224 }
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