Annotation of embedaddon/mrouted/igmp.c, revision 1.1.1.1
1.1 misho 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: #include "defs.h"
11:
12: /*
13: * Exported variables.
14: */
15: char *recv_buf; /* input packet buffer */
16: char *send_buf; /* output packet buffer */
17: int igmp_socket; /* socket for all network I/O */
18: u_int32 allhosts_group; /* All hosts addr in net order */
19: u_int32 allrtrs_group; /* All-Routers " in net order */
20: u_int32 dvmrp_group; /* DVMRP grp addr in net order */
21: u_int32 dvmrp_genid; /* IGMP generation id */
22:
23: /*
24: * Local function definitions.
25: */
26: /* u_char promoted to u_int */
27: static int igmp_log_level(u_int type, u_int code);
28:
29: /*
30: * Open and initialize the igmp socket, and fill in the non-changing
31: * IP header fields in the output packet buffer.
32: */
33: void init_igmp(void)
34: {
35: struct ip *ip;
36:
37: recv_buf = malloc(RECV_BUF_SIZE);
38: send_buf = malloc(RECV_BUF_SIZE);
39:
40: if ((igmp_socket = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP)) < 0)
41: logit(LOG_ERR, errno, "IGMP socket");
42:
43: k_hdr_include(TRUE); /* include IP header when sending */
44: k_set_rcvbuf(256*1024,48*1024); /* lots of input buffering */
45: k_set_ttl(1); /* restrict multicasts to one hop */
46: k_set_loop(FALSE); /* disable multicast loopback */
47:
48: ip = (struct ip *)send_buf;
49: memset(ip, 0, sizeof(struct ip));
50: /*
51: * Fields zeroed that aren't filled in later:
52: * - IP ID (let the kernel fill it in)
53: * - Offset (we don't send fragments)
54: * - Checksum (let the kernel fill it in)
55: */
56: ip->ip_v = IPVERSION;
57: ip->ip_hl = sizeof(struct ip) >> 2;
58: ip->ip_tos = 0xc0; /* Internet Control */
59: ip->ip_ttl = MAXTTL; /* applies to unicasts only */
60: ip->ip_p = IPPROTO_IGMP;
61:
62: allhosts_group = htonl(INADDR_ALLHOSTS_GROUP);
63: dvmrp_group = htonl(INADDR_DVMRP_GROUP);
64: allrtrs_group = htonl(INADDR_ALLRTRS_GROUP);
65: }
66:
67: #define PIM_QUERY 0
68: #define PIM_REGISTER 1
69: #define PIM_REGISTER_STOP 2
70: #define PIM_JOIN_PRUNE 3
71: #define PIM_RP_REACHABLE 4
72: #define PIM_ASSERT 5
73: #define PIM_GRAFT 6
74: #define PIM_GRAFT_ACK 7
75:
76: char *igmp_packet_kind(u_int type, u_int code)
77: {
78: static char unknown[20];
79:
80: switch (type) {
81: case IGMP_MEMBERSHIP_QUERY: return "membership query ";
82: case IGMP_V1_MEMBERSHIP_REPORT: return "V1 member report ";
83: case IGMP_V2_MEMBERSHIP_REPORT: return "V2 member report ";
84: case IGMP_V2_LEAVE_GROUP: return "leave message ";
85: case IGMP_DVMRP:
86: switch (code) {
87: case DVMRP_PROBE: return "neighbor probe ";
88: case DVMRP_REPORT: return "route report ";
89: case DVMRP_ASK_NEIGHBORS: return "neighbor request ";
90: case DVMRP_NEIGHBORS: return "neighbor list ";
91: case DVMRP_ASK_NEIGHBORS2: return "neighbor request 2";
92: case DVMRP_NEIGHBORS2: return "neighbor list 2 ";
93: case DVMRP_PRUNE: return "prune message ";
94: case DVMRP_GRAFT: return "graft message ";
95: case DVMRP_GRAFT_ACK: return "graft message ack ";
96: case DVMRP_INFO_REQUEST: return "info request ";
97: case DVMRP_INFO_REPLY: return "info reply ";
98: default:
99: snprintf(unknown, sizeof(unknown), "unknown DVMRP %3d ", code);
100: return unknown;
101: }
102: case IGMP_PIM:
103: switch (code) {
104: case PIM_QUERY: return "PIM Router-Query ";
105: case PIM_REGISTER: return "PIM Register ";
106: case PIM_REGISTER_STOP: return "PIM Register-Stop ";
107: case PIM_JOIN_PRUNE: return "PIM Join/Prune ";
108: case PIM_RP_REACHABLE: return "PIM RP-Reachable ";
109: case PIM_ASSERT: return "PIM Assert ";
110: case PIM_GRAFT: return "PIM Graft ";
111: case PIM_GRAFT_ACK: return "PIM Graft-Ack ";
112: default:
113: snprintf(unknown, sizeof(unknown), "unknown PIM msg%3d", code);
114: return unknown;
115: }
116: case IGMP_MTRACE: return "IGMP trace query ";
117: case IGMP_MTRACE_RESP: return "IGMP trace reply ";
118: default:
119: snprintf(unknown, sizeof(unknown), "unk: 0x%02x/0x%02x ", type, code);
120: return unknown;
121: }
122: }
123:
124: int igmp_debug_kind(u_int type, u_int code)
125: {
126: switch (type) {
127: case IGMP_MEMBERSHIP_QUERY: return DEBUG_IGMP;
128: case IGMP_V1_MEMBERSHIP_REPORT: return DEBUG_IGMP;
129: case IGMP_V2_MEMBERSHIP_REPORT: return DEBUG_IGMP;
130: case IGMP_V2_LEAVE_GROUP: return DEBUG_IGMP;
131: case IGMP_DVMRP:
132: switch (code) {
133: case DVMRP_PROBE: return DEBUG_PEER;
134: case DVMRP_REPORT: return DEBUG_ROUTE;
135: case DVMRP_ASK_NEIGHBORS: return 0;
136: case DVMRP_NEIGHBORS: return 0;
137: case DVMRP_ASK_NEIGHBORS2: return 0;
138: case DVMRP_NEIGHBORS2: return 0;
139: case DVMRP_PRUNE: return DEBUG_PRUNE;
140: case DVMRP_GRAFT: return DEBUG_PRUNE;
141: case DVMRP_GRAFT_ACK: return DEBUG_PRUNE;
142: case DVMRP_INFO_REQUEST: return 0;
143: case DVMRP_INFO_REPLY: return 0;
144: default: return 0;
145: }
146: case IGMP_PIM:
147: switch (code) {
148: case PIM_QUERY: return 0;
149: case PIM_REGISTER: return 0;
150: case PIM_REGISTER_STOP: return 0;
151: case PIM_JOIN_PRUNE: return 0;
152: case PIM_RP_REACHABLE: return 0;
153: case PIM_ASSERT: return 0;
154: case PIM_GRAFT: return 0;
155: case PIM_GRAFT_ACK: return 0;
156: default: return 0;
157: }
158: case IGMP_MTRACE: return DEBUG_TRACE;
159: case IGMP_MTRACE_RESP: return DEBUG_TRACE;
160: default: return DEBUG_IGMP;
161: }
162: }
163:
164: /*
165: * Process a newly received IGMP packet that is sitting in the input
166: * packet buffer.
167: */
168: void accept_igmp(size_t recvlen)
169: {
170: register u_int32 src, dst, group;
171: struct ip *ip;
172: struct igmp *igmp;
173: int ipdatalen, iphdrlen, igmpdatalen;
174:
175: if (recvlen < sizeof(struct ip)) {
176: logit(LOG_WARNING, 0,
177: "received packet too short (%u bytes) for IP header", recvlen);
178: return;
179: }
180:
181: ip = (struct ip *)recv_buf;
182: src = ip->ip_src.s_addr;
183: dst = ip->ip_dst.s_addr;
184:
185: /*
186: * this is most likely a message from the kernel indicating that
187: * a new src grp pair message has arrived and so, it would be
188: * necessary to install a route into the kernel for this.
189: */
190: if (ip->ip_p == 0) {
191: if (src == 0 || dst == 0)
192: logit(LOG_WARNING, 0, "kernel request not accurate");
193: else
194: add_table_entry(src, dst);
195: return;
196: }
197:
198: iphdrlen = ip->ip_hl << 2;
199: ipdatalen = ntohs(ip->ip_len) - iphdrlen;
200: if ((size_t)(iphdrlen + ipdatalen) != recvlen) {
201: logit(LOG_WARNING, 0,
202: "received packet from %s shorter (%u bytes) than hdr+data length (%u+%u)",
203: inet_fmt(src, s1, sizeof(s1)), recvlen, iphdrlen, ipdatalen);
204: return;
205: }
206:
207: igmp = (struct igmp *)(recv_buf + iphdrlen);
208: group = igmp->igmp_group.s_addr;
209: igmpdatalen = ipdatalen - IGMP_MINLEN;
210: if (igmpdatalen < 0) {
211: logit(LOG_WARNING, 0,
212: "received IP data field too short (%u bytes) for IGMP, from %s",
213: ipdatalen, inet_fmt(src, s1, sizeof(s1)));
214: return;
215: }
216:
217: IF_DEBUG(DEBUG_PKT|igmp_debug_kind(igmp->igmp_type, igmp->igmp_code))
218: logit(LOG_DEBUG, 0, "RECV %s from %-15s to %s",
219: igmp_packet_kind(igmp->igmp_type, igmp->igmp_code),
220: inet_fmt(src, s1, sizeof(s1)), inet_fmt(dst, s2, sizeof(s2)));
221:
222: switch (igmp->igmp_type) {
223:
224: case IGMP_MEMBERSHIP_QUERY:
225: accept_membership_query(src, dst, group, igmp->igmp_code);
226: return;
227:
228: case IGMP_V1_MEMBERSHIP_REPORT:
229: case IGMP_V2_MEMBERSHIP_REPORT:
230: accept_group_report(src, dst, group, igmp->igmp_type);
231: return;
232:
233: case IGMP_V2_LEAVE_GROUP:
234: accept_leave_message(src, dst, group);
235: return;
236:
237: case IGMP_DVMRP:
238: group = ntohl(group);
239:
240: switch (igmp->igmp_code) {
241: case DVMRP_PROBE:
242: accept_probe(src, dst, (char *)(igmp+1), igmpdatalen, group);
243: return;
244:
245: case DVMRP_REPORT:
246: accept_report(src, dst, (char *)(igmp+1), igmpdatalen, group);
247: return;
248:
249: case DVMRP_ASK_NEIGHBORS:
250: accept_neighbor_request(src, dst);
251: return;
252:
253: case DVMRP_ASK_NEIGHBORS2:
254: accept_neighbor_request2(src, dst);
255: return;
256:
257: case DVMRP_NEIGHBORS:
258: accept_neighbors(src, dst, (u_char *)(igmp+1), igmpdatalen, group);
259: return;
260:
261: case DVMRP_NEIGHBORS2:
262: accept_neighbors2(src, dst, (u_char *)(igmp+1), igmpdatalen, group);
263: return;
264:
265: case DVMRP_PRUNE:
266: accept_prune(src, dst, (char *)(igmp+1), igmpdatalen);
267: return;
268:
269: case DVMRP_GRAFT:
270: accept_graft(src, dst, (char *)(igmp+1), igmpdatalen);
271: return;
272:
273: case DVMRP_GRAFT_ACK:
274: accept_g_ack(src, dst, (char *)(igmp+1), igmpdatalen);
275: return;
276:
277: case DVMRP_INFO_REQUEST:
278: accept_info_request(src, dst, (u_char *)(igmp+1), igmpdatalen);
279: return;
280:
281: case DVMRP_INFO_REPLY:
282: accept_info_reply(src, dst, (u_char *)(igmp+1), igmpdatalen);
283: return;
284:
285: default:
286: logit(LOG_INFO, 0,
287: "ignoring unknown DVMRP message code %u from %s to %s",
288: igmp->igmp_code, inet_fmt(src, s1, sizeof(s1)),
289: inet_fmt(dst, s2, sizeof(s2)));
290: return;
291: }
292:
293: case IGMP_PIM:
294: return;
295:
296: case IGMP_MTRACE_RESP:
297: return;
298:
299: case IGMP_MTRACE:
300: accept_mtrace(src, dst, group, (char *)(igmp+1),
301: igmp->igmp_code, igmpdatalen);
302: return;
303:
304: default:
305: logit(LOG_INFO, 0,
306: "ignoring unknown IGMP message type %x from %s to %s",
307: igmp->igmp_type, inet_fmt(src, s1, sizeof(s1)),
308: inet_fmt(dst, s2, sizeof(s2)));
309: return;
310: }
311: }
312:
313: /*
314: * Some IGMP messages are more important than others. This routine
315: * determines the logging level at which to log a send error (often
316: * "No route to host"). This is important when there is asymmetric
317: * reachability and someone is trying to, i.e., mrinfo me periodically.
318: */
319: static int igmp_log_level(u_int type, u_int code)
320: {
321: switch (type) {
322: case IGMP_MTRACE_RESP:
323: return LOG_INFO;
324:
325: case IGMP_DVMRP:
326: switch (code) {
327: case DVMRP_NEIGHBORS:
328: case DVMRP_NEIGHBORS2:
329: return LOG_INFO;
330: }
331: }
332: return LOG_WARNING;
333: }
334:
335: /*
336: * Construct an IGMP message in the output packet buffer. The caller may
337: * have already placed data in that buffer, of length 'datalen'.
338: */
339: size_t build_igmp(u_int32 src, u_int32 dst, int type, int code, u_int32 group, int datalen)
340: {
341: struct ip *ip;
342: struct igmp *igmp;
343: extern int curttl;
344: size_t len = MIN_IP_HEADER_LEN + IGMP_MINLEN + datalen;
345:
346: ip = (struct ip *)send_buf;
347: ip->ip_src.s_addr = src;
348: ip->ip_dst.s_addr = dst;
349: ip->ip_len = htons(len);
350: if (IN_MULTICAST(ntohl(dst))) {
351: ip->ip_ttl = curttl;
352: } else {
353: ip->ip_ttl = MAXTTL;
354: }
355:
356: igmp = (struct igmp *)(send_buf + MIN_IP_HEADER_LEN);
357: igmp->igmp_type = type;
358: igmp->igmp_code = code;
359: igmp->igmp_group.s_addr = group;
360: igmp->igmp_cksum = 0;
361: igmp->igmp_cksum = inet_cksum((u_int16_t *)igmp,
362: IGMP_MINLEN + datalen);
363:
364: return len;
365: }
366:
367: /*
368: * Call build_igmp() to build an IGMP message in the output packet buffer.
369: * Then send the message from the interface with IP address 'src' to
370: * destination 'dst'.
371: */
372: void send_igmp(u_int32 src, u_int32 dst, int type, int code, u_int32 group, int datalen)
373: {
374: struct sockaddr_in sdst;
375: int setloop = 0;
376: size_t len;
377:
378: len = build_igmp(src, dst, type, code, group, datalen);
379:
380: if (IN_MULTICAST(ntohl(dst))) {
381: k_set_if(src);
382: if (type != IGMP_DVMRP || dst == allhosts_group) {
383: setloop = 1;
384: k_set_loop(TRUE);
385: }
386: }
387:
388: memset(&sdst, 0, sizeof(sdst));
389: sdst.sin_family = AF_INET;
390: #ifdef HAVE_SA_LEN
391: sdst.sin_len = sizeof(sdst);
392: #endif
393: sdst.sin_addr.s_addr = dst;
394: if (sendto(igmp_socket, send_buf, len, 0, (struct sockaddr *)&sdst, sizeof(sdst)) < 0) {
395: if (errno == ENETDOWN)
396: check_vif_state();
397: else
398: logit(igmp_log_level(type, code), errno,
399: "sendto to %s on %s",
400: inet_fmt(dst, s1, sizeof(s1)), inet_fmt(src, s2, sizeof(s2)));
401: }
402:
403: if (setloop)
404: k_set_loop(FALSE);
405:
406: IF_DEBUG(DEBUG_PKT|igmp_debug_kind(type, code))
407: logit(LOG_DEBUG, 0, "SENT %s from %-15s to %s",
408: igmp_packet_kind(type, code), src == INADDR_ANY ? "INADDR_ANY" :
409: inet_fmt(src, s1, sizeof(s1)), inet_fmt(dst, s2, sizeof(s2)));
410: }
411:
412: /**
413: * Local Variables:
414: * version-control: t
415: * indent-tabs-mode: t
416: * c-file-style: "ellemtel"
417: * c-basic-offset: 4
418: * End:
419: */
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