igmp.c revision 1.3
1 /* 2 * The mrouted program is covered by the license in the accompanying file 3 * named "LICENSE". Use of the mrouted program represents acceptance of 4 * the terms and conditions listed in that file. 5 * 6 * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of 7 * Leland Stanford Junior University. 8 * 9 * 10 * $Id: igmp.c,v 1.3 1995/06/01 02:25:53 mycroft Exp $ 11 */ 12 13 14 #include "defs.h" 15 16 17 /* 18 * Exported variables. 19 */ 20 char *recv_buf; /* input packet buffer */ 21 char *send_buf; /* output packet buffer */ 22 int igmp_socket; /* socket for all network I/O */ 23 u_int32_t allhosts_group; /* All hosts addr in net order */ 24 u_int32_t allrtrs_group; /* All-Routers " in net order */ 25 u_int32_t dvmrp_group; /* DVMRP grp addr in net order */ 26 u_int32_t dvmrp_genid; /* IGMP generation id */ 27 28 /* 29 * Open and initialize the igmp socket, and fill in the non-changing 30 * IP header fields in the output packet buffer. 31 */ 32 void init_igmp() 33 { 34 struct ip *ip; 35 36 recv_buf = malloc(RECV_BUF_SIZE); 37 send_buf = malloc(RECV_BUF_SIZE); 38 39 if ((igmp_socket = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP)) < 0) 40 log(LOG_ERR, errno, "IGMP socket"); 41 42 k_hdr_include(TRUE); /* include IP header when sending */ 43 k_set_rcvbuf(48*1024); /* lots of input buffering */ 44 k_set_ttl(1); /* restrict multicasts to one hop */ 45 k_set_loop(FALSE); /* disable multicast loopback */ 46 47 ip = (struct ip *)send_buf; 48 ip->ip_hl = sizeof(struct ip) >> 2; 49 ip->ip_v = IPVERSION; 50 ip->ip_tos = 0; 51 ip->ip_off = 0; 52 ip->ip_p = IPPROTO_IGMP; 53 ip->ip_ttl = MAXTTL; /* applies to unicasts only */ 54 55 allhosts_group = htonl(INADDR_ALLHOSTS_GROUP); 56 dvmrp_group = htonl(INADDR_DVMRP_GROUP); 57 allrtrs_group = htonl(INADDR_ALLRTRS_GROUP); 58 } 59 60 #define PIM_QUERY 0 61 #define PIM_REGISTER 1 62 #define PIM_REGISTER_STOP 2 63 #define PIM_JOIN_PRUNE 3 64 #define PIM_RP_REACHABLE 4 65 #define PIM_ASSERT 5 66 #define PIM_GRAFT 6 67 #define PIM_GRAFT_ACK 7 68 69 static char *packet_kind(type, code) 70 u_char type, code; 71 { 72 switch (type) { 73 case IGMP_HOST_MEMBERSHIP_QUERY: return "membership query "; 74 case IGMP_v1_HOST_MEMBERSHIP_REPORT: return "membership report "; 75 case IGMP_v2_HOST_MEMBERSHIP_REPORT: return "new member report "; 76 case IGMP_HOST_LEAVE_MESSAGE: return "leave message "; 77 case IGMP_DVMRP: 78 switch (code) { 79 case DVMRP_PROBE: return "neighbor probe "; 80 case DVMRP_REPORT: return "route report "; 81 case DVMRP_ASK_NEIGHBORS: return "neighbor request "; 82 case DVMRP_NEIGHBORS: return "neighbor list "; 83 case DVMRP_ASK_NEIGHBORS2: return "neighbor request 2"; 84 case DVMRP_NEIGHBORS2: return "neighbor list 2 "; 85 case DVMRP_PRUNE: return "prune message "; 86 case DVMRP_GRAFT: return "graft message "; 87 case DVMRP_GRAFT_ACK: return "graft message ack "; 88 default: return "unknown DVMRP msg "; 89 } 90 case IGMP_PIM: 91 switch (code) { 92 case PIM_QUERY: return "PIM Router-Query "; 93 case PIM_REGISTER: return "PIM Register "; 94 case PIM_REGISTER_STOP: return "PIM Register-Stop "; 95 case PIM_JOIN_PRUNE: return "PIM Join/Prune "; 96 case PIM_RP_REACHABLE: return "PIM RP-Reachable "; 97 case PIM_ASSERT: return "PIM Assert "; 98 case PIM_GRAFT: return "PIM Graft "; 99 case PIM_GRAFT_ACK: return "PIM Graft-Ack "; 100 default: return "unknown PIM msg "; 101 } 102 case IGMP_MTRACE_QUERY: return "IGMP trace query "; 103 case IGMP_MTRACE_REPLY: return "IGMP trace reply "; 104 default: return "unknown IGMP msg "; 105 } 106 } 107 108 /* 109 * Process a newly received IGMP packet that is sitting in the input 110 * packet buffer. 111 */ 112 void accept_igmp(recvlen) 113 int recvlen; 114 { 115 register u_int32_t src, dst, group; 116 struct ip *ip; 117 struct igmp *igmp; 118 int ipdatalen, iphdrlen, igmpdatalen; 119 120 if (recvlen < sizeof(struct ip)) { 121 log(LOG_WARNING, 0, 122 "received packet too short (%u bytes) for IP header", recvlen); 123 return; 124 } 125 126 ip = (struct ip *)recv_buf; 127 src = ip->ip_src.s_addr; 128 dst = ip->ip_dst.s_addr; 129 130 /* 131 * this is most likely a message from the kernel indicating that 132 * a new src grp pair message has arrived and so, it would be 133 * necessary to install a route into the kernel for this. 134 */ 135 if (ip->ip_p == 0) { 136 if (src == 0 || dst == 0) 137 log(LOG_WARNING, 0, "kernel request not accurate"); 138 else 139 add_table_entry(src, dst); 140 return; 141 } 142 143 iphdrlen = ip->ip_hl << 2; 144 ipdatalen = ip->ip_len; 145 if (iphdrlen + ipdatalen != recvlen) { 146 log(LOG_WARNING, 0, 147 "received packet shorter (%u bytes) than hdr+data length (%u+%u)", 148 recvlen, iphdrlen, ipdatalen); 149 return; 150 } 151 152 igmp = (struct igmp *)(recv_buf + iphdrlen); 153 group = igmp->igmp_group.s_addr; 154 igmpdatalen = ipdatalen - IGMP_MINLEN; 155 if (igmpdatalen < 0) { 156 log(LOG_WARNING, 0, 157 "received IP data field too short (%u bytes) for IGMP, from %s", 158 ipdatalen, inet_fmt(src, s1)); 159 return; 160 } 161 162 log(LOG_DEBUG, 0, "RECV %s from %-15s to %s", 163 packet_kind(igmp->igmp_type, igmp->igmp_code), 164 inet_fmt(src, s1), inet_fmt(dst, s2)); 165 166 switch (igmp->igmp_type) { 167 168 case IGMP_HOST_MEMBERSHIP_QUERY: 169 accept_membership_query(src, dst, group, igmp->igmp_code); 170 return; 171 172 case IGMP_v1_HOST_MEMBERSHIP_REPORT: 173 case IGMP_v2_HOST_MEMBERSHIP_REPORT: 174 accept_group_report(src, dst, group, igmp->igmp_type); 175 return; 176 177 case IGMP_HOST_LEAVE_MESSAGE: 178 accept_leave_message(src, dst, group); 179 return; 180 181 case IGMP_DVMRP: 182 group = ntohl(group); 183 184 switch (igmp->igmp_code) { 185 case DVMRP_PROBE: 186 accept_probe(src, dst, 187 (char *)(igmp+1), igmpdatalen, group); 188 return; 189 190 case DVMRP_REPORT: 191 accept_report(src, dst, 192 (char *)(igmp+1), igmpdatalen, group); 193 return; 194 195 case DVMRP_ASK_NEIGHBORS: 196 accept_neighbor_request(src, dst); 197 return; 198 199 case DVMRP_ASK_NEIGHBORS2: 200 accept_neighbor_request2(src, dst); 201 return; 202 203 case DVMRP_NEIGHBORS: 204 accept_neighbors(src, dst, (char *)(igmp+1), igmpdatalen, 205 group); 206 return; 207 208 case DVMRP_NEIGHBORS2: 209 accept_neighbors2(src, dst, (char *)(igmp+1), igmpdatalen, 210 group); 211 return; 212 213 case DVMRP_PRUNE: 214 accept_prune(src, dst, (char *)(igmp+1), igmpdatalen); 215 return; 216 217 case DVMRP_GRAFT: 218 accept_graft(src, dst, (char *)(igmp+1), igmpdatalen); 219 return; 220 221 case DVMRP_GRAFT_ACK: 222 accept_g_ack(src, dst, (char *)(igmp+1), igmpdatalen); 223 return; 224 225 default: 226 log(LOG_INFO, 0, 227 "ignoring unknown DVMRP message code %u from %s to %s", 228 igmp->igmp_code, inet_fmt(src, s1), 229 inet_fmt(dst, s2)); 230 return; 231 } 232 233 case IGMP_PIM: 234 return; 235 236 case IGMP_MTRACE_REPLY: 237 return; 238 239 case IGMP_MTRACE_QUERY: 240 accept_mtrace(src, dst, group, (char *)(igmp+1), 241 igmp->igmp_code, igmpdatalen); 242 return; 243 244 default: 245 log(LOG_INFO, 0, 246 "ignoring unknown IGMP message type %x from %s to %s", 247 igmp->igmp_type, inet_fmt(src, s1), 248 inet_fmt(dst, s2)); 249 return; 250 } 251 } 252 253 254 /* 255 * Construct an IGMP message in the output packet buffer. The caller may 256 * have already placed data in that buffer, of length 'datalen'. Then send 257 * the message from the interface with IP address 'src' to destination 'dst'. 258 */ 259 void 260 send_igmp(src, dst, type, code, group, datalen) 261 u_int32_t src, dst; 262 int type, code; 263 u_int32_t group; 264 int datalen; 265 { 266 static struct sockaddr_in sdst; 267 struct ip *ip; 268 struct igmp *igmp; 269 270 ip = (struct ip *)send_buf; 271 ip->ip_src.s_addr = src; 272 ip->ip_dst.s_addr = dst; 273 ip->ip_len = MIN_IP_HEADER_LEN + IGMP_MINLEN + datalen; 274 275 igmp = (struct igmp *)(send_buf + MIN_IP_HEADER_LEN); 276 igmp->igmp_type = type; 277 igmp->igmp_code = code; 278 igmp->igmp_group.s_addr = group; 279 igmp->igmp_cksum = 0; 280 igmp->igmp_cksum = inet_cksum((u_short *)igmp, 281 IGMP_MINLEN + datalen); 282 283 if (IN_MULTICAST(ntohl(dst))) k_set_if(src); 284 if (dst == allhosts_group) k_set_loop(TRUE); 285 286 bzero(&sdst, sizeof(sdst)); 287 sdst.sin_family = AF_INET; 288 #if (defined(BSD) && (BSD >= 199103)) 289 sdst.sin_len = sizeof(sdst); 290 #endif 291 sdst.sin_addr.s_addr = dst; 292 if (sendto(igmp_socket, send_buf, ip->ip_len, 0, 293 (struct sockaddr *)&sdst, sizeof(sdst)) < 0) { 294 if (errno == ENETDOWN) 295 check_vif_state(); 296 else 297 log(LOG_WARNING, errno, 298 "sendto to %s on %s", 299 inet_fmt(dst, s1), inet_fmt(src, s2)); 300 } 301 302 if (dst == allhosts_group) k_set_loop(FALSE); 303 304 log(LOG_DEBUG, 0, "SENT %s from %-15s to %s", 305 packet_kind(type, code), inet_fmt(src, s1), inet_fmt(dst, s2)); 306 } 307
Indexes created Wed Sep 24 05:09:52 GMT 2025