8447845f |
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 | |
12 | #include "mcast.h" |
13 | #include "sap.h" |
14 | |
15 | #define SAP_ADDR "224.2.127.254" |
16 | #define SAP_PORT 9875 |
17 | #define SAP_MAX_SIZE 1024 |
18 | |
19 | #define SAP_TIMEOUT 3 |
20 | |
21 | #define BUFFSIZE SAP_MAX_SIZE |
22 | |
23 | char *get_url_from_sap(char *service) |
24 | { |
25 | struct timeval start, curr; |
26 | struct ip_mreq mreq; |
27 | unsigned char buffer[BUFFSIZE]; |
28 | char *url = NULL; |
29 | int fd; |
30 | |
31 | snprintf(buffer,BUFFSIZE,"udp://%s:%u", SAP_ADDR, SAP_PORT); |
32 | |
33 | fd = open_mcast(buffer); |
34 | |
35 | gettimeofday(&start, NULL); |
36 | |
37 | do { |
38 | int recvd; |
39 | int sap_version, sap_addrtype, sap_messagetype, sap_encrypted, sap_compressed; |
40 | in_addr_t sender_address; |
41 | unsigned char auth_len; |
42 | unsigned short msgid; |
43 | unsigned char *payload, *pos, *host = NULL, *proto = NULL, *port = NULL, *sname = NULL; |
44 | |
45 | if ((recvd = recv(fd, buffer, BUFFSIZE, 0)) < 1) { |
46 | perror("recv"); |
47 | return NULL; |
48 | } |
49 | |
50 | gettimeofday(&curr, NULL); |
51 | |
52 | sap_version = (buffer[0] >> 5) & 0x7; |
53 | sap_addrtype = (buffer[0] >> 4) & 0x1; |
54 | sap_messagetype = (buffer[0] >> 2) & 0x1; |
55 | sap_encrypted = (buffer[0] >> 1) & 0x1; |
56 | sap_compressed = buffer[0] & 0x1; |
57 | auth_len = buffer[1]; |
58 | msgid = buffer[2] << 8 | buffer[3]; |
59 | memcpy(&sender_address, buffer+4, (sap_addrtype?16:4)); |
60 | payload = buffer + 4 /* (sap_*, auth_len, msgid) */ + (sap_addrtype?16:4) + auth_len; |
61 | |
62 | #ifdef DEBUG |
63 | printf("\n"); |
64 | printf("SAP-Version: %d\n", sap_version); |
65 | printf("Adresstyp: %s\n", (sap_addrtype?"IPv6":"IPv4")); |
66 | printf("Messagetype: %s\n", (sap_messagetype?"Announcement":"Deletion")); |
67 | printf("Encrypted: %d\n", sap_encrypted); |
68 | printf("Compressed: %d\n", sap_compressed); |
69 | printf("Authentication Length: %d\n", auth_len); |
70 | printf("Sender: %u\n", sender_address); |
71 | printf("Message Identifier Hash: %u\n", msgid); |
72 | #endif |
73 | |
74 | if (sap_addrtype) |
75 | continue; /* We don't support IPv6 for now */ |
76 | |
77 | #if 0 /* Getstream gets this wrong, see rfc2974 */ |
78 | if (sap_messagetype) |
79 | continue; /* We are not interested in deletions */ |
80 | #endif |
81 | |
82 | if (sap_encrypted || sap_compressed) |
83 | continue; |
84 | /* RFC 2327 |
85 | * v=0 |
86 | * o=- 6dca 1 IN IP4 192.168.100.17:2000 |
87 | * s=TV Das Erste |
88 | * t=0 0 |
89 | * c=IN IP4 192.168.100.17/1 |
90 | * m=video 2000 http 33 |
91 | * a=tool:getstream |
92 | * a=type:broadcast |
93 | */ |
94 | |
95 | pos = payload; |
96 | while(*pos != 0 && (pos-buffer) < BUFFSIZE) { |
97 | if (*pos == 0x0d) { |
98 | *pos = 0; |
99 | } |
100 | |
101 | if (*pos == 0x0a) { |
102 | *pos = 0; |
103 | |
104 | if (!strncasecmp("s=", payload, 2)) { |
105 | sname = payload + 2; |
106 | } else if (!strncasecmp("c=", payload, 2)) { |
107 | int poscnt = 0; |
108 | |
109 | payload += 2; |
110 | while (*payload != 0) { |
111 | if (poscnt == 2 && *payload == '/') { |
112 | *payload = 0; |
113 | break; |
114 | } |
115 | |
116 | if (*payload == ' ') { |
117 | *payload = 0; |
118 | poscnt++; |
119 | |
120 | /* c=<network type> <address type> <connection address> */ |
121 | if (poscnt == 2) { |
122 | host = payload + 1; |
123 | } |
124 | |
125 | if (poscnt > 2) { |
126 | break; |
127 | } |
128 | } |
129 | payload++; |
130 | } |
131 | } else if (!strncasecmp("m=", payload, 2)) { |
132 | int poscnt = 0; |
133 | |
134 | payload += 2; |
135 | while (*payload != 0) { |
136 | if (*payload == ' ') { |
137 | *payload = 0; |
138 | poscnt++; |
139 | |
140 | /* m=<media> <port> <transport> <fmt list> */ |
141 | if (poscnt == 1) { |
142 | port = payload + 1; |
143 | } |
144 | |
145 | if (poscnt == 2) { |
146 | proto = payload + 1; |
147 | } |
148 | |
149 | if (poscnt > 2) { |
150 | break; |
151 | } |
152 | } |
153 | payload++; |
154 | } |
155 | } |
156 | |
157 | payload = ++pos; |
158 | continue; |
159 | } |
160 | pos++; |
161 | } |
162 | |
163 | if (sname && proto && port) { |
164 | if (!host) { |
165 | struct in_addr inaddr; |
166 | |
167 | inaddr.s_addr = sender_address; |
168 | host = inet_ntoa(inaddr); |
169 | } |
170 | |
171 | #ifdef DEBUG |
172 | printf("%s -> %s://%s:%s\n", sname, proto, host, port); |
173 | #endif |
174 | |
175 | if (strlen(service) < strlen(sname)) { |
176 | sname += strlen(sname) - strlen(service); |
177 | } |
178 | |
179 | if (!strncasecmp(service, sname, strlen(service))) { |
180 | int len = strlen(host)+strlen(proto)+strlen(port)+5; |
181 | |
182 | if (!(url = malloc(len))) { |
183 | perror("malloc"); |
184 | return NULL; |
185 | } |
186 | |
187 | snprintf(url, len, "%s://%s:%s", proto, host, port); |
188 | url[len-1] = 0; |
189 | break; |
190 | } |
191 | } |
192 | |
193 | } while(curr.tv_sec < start.tv_sec+SAP_TIMEOUT); |
194 | |
195 | mreq.imr_multiaddr.s_addr = inet_addr(SAP_ADDR); |
196 | mreq.imr_interface.s_addr = INADDR_ANY; |
197 | setsockopt (fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq, sizeof(mreq)); |
198 | |
199 | return url; |
200 | } |