1: /*
2: * Copyright (c) 1998 by the University of Southern California.
3: * All rights reserved.
4: *
5: * Permission to use, copy, modify, and distribute this software and
6: * its documentation in source and binary forms for lawful
7: * purposes and without fee is hereby granted, provided
8: * that the above copyright notice appear in all copies and that both
9: * the copyright notice and this permission notice appear in supporting
10: * documentation, and that any documentation, advertising materials,
11: * and other materials related to such distribution and use acknowledge
12: * that the software was developed by the University of Southern
13: * California and/or Information Sciences Institute.
14: * The name of the University of Southern California may not
15: * be used to endorse or promote products derived from this software
16: * without specific prior written permission.
17: *
18: * THE UNIVERSITY OF SOUTHERN CALIFORNIA DOES NOT MAKE ANY REPRESENTATIONS
19: * ABOUT THE SUITABILITY OF THIS SOFTWARE FOR ANY PURPOSE. THIS SOFTWARE IS
20: * PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
21: * INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
22: * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND
23: * NON-INFRINGEMENT.
24: *
25: * IN NO EVENT SHALL USC, OR ANY OTHER CONTRIBUTOR BE LIABLE FOR ANY
26: * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES, WHETHER IN CONTRACT,
27: * TORT, OR OTHER FORM OF ACTION, ARISING OUT OF OR IN CONNECTION WITH,
28: * THE USE OR PERFORMANCE OF THIS SOFTWARE.
29: *
30: * Other copyrights might apply to parts of this software and are so
31: * noted when applicable.
32: */
33: /*
34: * Questions concerning this software should be directed to
35: * Pavlin Ivanov Radoslavov (pavlin@catarina.usc.edu)
36: *
37: * $Id: igmp.c,v 1.1.1.1 2017/06/12 07:58:55 misho Exp $
38: */
39: /*
40: * Part of this program has been derived from mrouted.
41: * The mrouted program is covered by the license in the accompanying file
42: * named "LICENSE.mrouted".
43: *
44: * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
45: * Leland Stanford Junior University.
46: *
47: */
48:
49: #include "defs.h"
50:
51: /*
52: * Exported variables.
53: */
54: char *igmp_recv_buf; /* input packet buffer */
55: char *igmp_send_buf; /* output packet buffer */
56: int igmp_socket; /* socket for all network I/O */
57: u_int32 allhosts_group; /* allhosts addr in net order */
58: u_int32 allrouters_group; /* All-Routers addr in net order */
59:
60: /*
61: * Local functions definitions.
62: */
63: static void igmp_read __P((int i, fd_set *rfd));
64: static void accept_igmp __P((int recvlen));
65:
66:
67: /*
68: * Open and initialize the igmp socket, and fill in the non-changing
69: * IP header fields in the output packet buffer.
70: */
71: void
72: init_igmp()
73: {
74: struct ip *ip;
75:
76: igmp_recv_buf = malloc(RECV_BUF_SIZE);
77: igmp_send_buf = malloc(RECV_BUF_SIZE);
78:
79: if ((igmp_socket = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP)) < 0)
80: log(LOG_ERR, errno, "IGMP socket");
81:
82: k_hdr_include(igmp_socket, TRUE); /* include IP header when sending */
83: k_set_rcvbuf(igmp_socket, SO_RECV_BUF_SIZE_MAX,
84: SO_RECV_BUF_SIZE_MIN); /* lots of input buffering */
85: k_set_ttl(igmp_socket, MINTTL); /* restrict multicasts to one hop */
86: k_set_loop(igmp_socket, FALSE); /* disable multicast loopback */
87:
88: ip = (struct ip *)igmp_send_buf;
89: ip->ip_v = IPVERSION;
90: ip->ip_hl = (sizeof(struct ip) >> 2);
91: ip->ip_tos = 0xc0; /* Internet Control */
92: ip->ip_id = 0; /* let kernel fill in */
93: ip->ip_off = 0;
94: ip->ip_ttl = MAXTTL; /* applies to unicasts only */
95: ip->ip_p = IPPROTO_IGMP;
96: #ifdef Linux
97: ip->ip_csum = 0; /* let kernel fill in */
98: #else
99: ip->ip_sum = 0; /* let kernel fill in */
100: #endif /* Linux */
101:
102: /* Everywhere in the daemon we use network-byte-order */
103: allhosts_group = htonl(INADDR_ALLHOSTS_GROUP);
104: allrouters_group = htonl(INADDR_ALLRTRS_GROUP);
105:
106: if (register_input_handler(igmp_socket, igmp_read) < 0)
107: log(LOG_ERR, 0, "Couldn't register igmp_read as an input handler");
108: }
109:
110:
111: /* Read an IGMP message */
112: static void
113: igmp_read(i, rfd)
114: int i;
115: fd_set *rfd;
116: {
117: register int igmp_recvlen;
118: int dummy = 0;
119:
120: igmp_recvlen = recvfrom(igmp_socket, igmp_recv_buf, RECV_BUF_SIZE,
121: 0, NULL, &dummy);
122:
123: if (igmp_recvlen < 0) {
124: if (errno != EINTR)
125: log(LOG_ERR, errno, "IGMP recvfrom");
126: return;
127: }
128:
129: /* TODO: make it as a thread in the future releases */
130: accept_igmp(igmp_recvlen);
131: }
132:
133:
134: /*
135: * Process a newly received IGMP packet that is sitting in the input
136: * packet buffer.
137: */
138: static void
139: accept_igmp(recvlen)
140: int recvlen;
141: {
142: register u_int32 src, dst, group;
143: struct ip *ip;
144: struct igmp *igmp;
145: int ipdatalen, iphdrlen, igmpdatalen;
146:
147: if (recvlen < sizeof(struct ip)) {
148: log(LOG_WARNING, 0,
149: "received packet too short (%u bytes) for IP header", recvlen);
150: return;
151: }
152:
153: ip = (struct ip *)igmp_recv_buf;
154: src = ip->ip_src.s_addr;
155: dst = ip->ip_dst.s_addr;
156:
157: /* packets sent up from kernel to daemon have ip->ip_p = 0 */
158: if (ip->ip_p == 0) {
159: if (src == 0 || dst == 0)
160: log(LOG_WARNING, 0, "kernel request not accurate, src %s dst %s",
161: inet_fmt(src, s1), inet_fmt(dst, s2));
162: else
163: process_kernel_call();
164: return;
165: }
166:
167: iphdrlen = ip->ip_hl << 2;
168: #ifdef RAW_INPUT_IS_RAW
169: ipdatalen = ntohs(ip->ip_len) - iphdrlen;
170: #else
171: ipdatalen = ip->ip_len;
172: #endif
173: if (iphdrlen + ipdatalen != recvlen) {
174: log(LOG_WARNING, 0,
175: "received packet from %s shorter (%u bytes) than hdr+data length (%u+%u)",
176: inet_fmt(src, s1), recvlen, iphdrlen, ipdatalen);
177: return;
178: }
179:
180: igmp = (struct igmp *)(igmp_recv_buf + iphdrlen);
181: group = igmp->igmp_group.s_addr;
182: igmpdatalen = ipdatalen - IGMP_MINLEN;
183: if (igmpdatalen < 0) {
184: log(LOG_WARNING, 0,
185: "received IP data field too short (%u bytes) for IGMP, from %s",
186: ipdatalen, inet_fmt(src, s1));
187: return;
188: }
189:
190: /* TODO: too noisy. Remove it? */
191: #ifdef NOSUCHDEF
192: IF_DEBUG(DEBUG_PKT | debug_kind(IPPROTO_IGMP, igmp->igmp_type,
193: igmp->igmp_code))
194: log(LOG_DEBUG, 0, "RECV %s from %-15s to %s",
195: packet_kind(IPPROTO_IGMP, igmp->igmp_type, igmp->igmp_code),
196: inet_fmt(src, s1), inet_fmt(dst, s2));
197: #endif /* NOSUCHDEF */
198:
199: switch (igmp->igmp_type) {
200: case IGMP_MEMBERSHIP_QUERY:
201: accept_membership_query(src, dst, group, igmp->igmp_code);
202: return;
203:
204: case IGMP_V1_MEMBERSHIP_REPORT:
205: case IGMP_V2_MEMBERSHIP_REPORT:
206: accept_group_report(src, dst, group, igmp->igmp_type);
207: return;
208:
209: case IGMP_V2_LEAVE_GROUP:
210: accept_leave_message(src, dst, group);
211: return;
212:
213: case IGMP_DVMRP:
214: /* XXX: TODO: most of the stuff below is not implemented. We are still
215: * only PIM router.
216: */
217: group = ntohl(group);
218:
219: switch (igmp->igmp_code) {
220: case DVMRP_PROBE:
221: dvmrp_accept_probe(src, dst, (char *)(igmp+1), igmpdatalen, group);
222: return;
223:
224: case DVMRP_REPORT:
225: dvmrp_accept_report(src, dst, (char *)(igmp+1), igmpdatalen,
226: group);
227: return;
228:
229: case DVMRP_ASK_NEIGHBORS:
230: accept_neighbor_request(src, dst);
231: return;
232:
233: case DVMRP_ASK_NEIGHBORS2:
234: accept_neighbor_request2(src, dst);
235: return;
236:
237: case DVMRP_NEIGHBORS:
238: dvmrp_accept_neighbors(src, dst, (u_char *)(igmp+1), igmpdatalen,
239: group);
240: return;
241:
242: case DVMRP_NEIGHBORS2:
243: dvmrp_accept_neighbors2(src, dst, (u_char *)(igmp+1), igmpdatalen,
244: group);
245: return;
246:
247: case DVMRP_PRUNE:
248: dvmrp_accept_prune(src, dst, (char *)(igmp+1), igmpdatalen);
249: return;
250:
251: case DVMRP_GRAFT:
252: dvmrp_accept_graft(src, dst, (char *)(igmp+1), igmpdatalen);
253: return;
254:
255: case DVMRP_GRAFT_ACK:
256: dvmrp_accept_g_ack(src, dst, (char *)(igmp+1), igmpdatalen);
257: return;
258:
259: case DVMRP_INFO_REQUEST:
260: dvmrp_accept_info_request(src, dst, (char *)(igmp+1), igmpdatalen);
261: return;
262:
263: case DVMRP_INFO_REPLY:
264: dvmrp_accept_info_reply(src, dst, (char *)(igmp+1), igmpdatalen);
265: return;
266:
267: default:
268: log(LOG_INFO, 0,
269: "ignoring unknown DVMRP message code %u from %s to %s",
270: igmp->igmp_code, inet_fmt(src, s1), inet_fmt(dst, s2));
271: return;
272: }
273:
274: case IGMP_PIM:
275: return; /* TODO: this is PIM v1 message. Handle it?. */
276:
277: case IGMP_MTRACE_RESP:
278: return; /* TODO: implement it */
279:
280: case IGMP_MTRACE:
281: accept_mtrace(src, dst, group, (char *)(igmp+1), igmp->igmp_code,
282: igmpdatalen);
283: return;
284:
285: default:
286: log(LOG_INFO, 0,
287: "ignoring unknown IGMP message type %x from %s to %s",
288: igmp->igmp_type, inet_fmt(src, s1), inet_fmt(dst, s2));
289: return;
290: }
291: }
292:
293: void
294: send_igmp(buf, src, dst, type, code, group, datalen)
295: char *buf;
296: u_int32 src, dst;
297: int type, code;
298: u_int32 group;
299: int datalen;
300: {
301: struct sockaddr_in sdst;
302: struct ip *ip;
303: struct igmp *igmp;
304: int sendlen;
305: #ifdef RAW_OUTPUT_IS_RAW
306: extern int curttl;
307: #endif /* RAW_OUTPUT_IS_RAW */
308: int setloop = 0;
309:
310: /* Prepare the IP header */
311: ip = (struct ip *)buf;
312: ip->ip_len = sizeof(struct ip) + IGMP_MINLEN + datalen;
313: ip->ip_src.s_addr = src;
314: ip->ip_dst.s_addr = dst;
315: sendlen = ip->ip_len;
316: #ifdef RAW_OUTPUT_IS_RAW
317: ip->ip_len = htons(ip->ip_len);
318: #endif /* RAW_OUTPUT_IS_RAW */
319:
320: igmp = (struct igmp *)(buf + sizeof(struct ip));
321: igmp->igmp_type = type;
322: igmp->igmp_code = code;
323: igmp->igmp_group.s_addr = group;
324: igmp->igmp_cksum = 0;
325: igmp->igmp_cksum = inet_cksum((u_int16 *)igmp,
326: IGMP_MINLEN + datalen);
327:
328: if (IN_MULTICAST(ntohl(dst))){
329: k_set_if(igmp_socket, src);
330: if (type != IGMP_DVMRP || dst == allhosts_group) {
331: setloop = 1;
332: k_set_loop(igmp_socket, TRUE);
333: }
334: #ifdef RAW_OUTPUT_IS_RAW
335: ip->ip_ttl = curttl;
336: } else {
337: ip->ip_ttl = MAXTTL;
338: #endif /* RAW_OUTPUT_IS_RAW */
339: }
340:
341: bzero((void *)&sdst, sizeof(sdst));
342: sdst.sin_family = AF_INET;
343: #ifdef HAVE_SA_LEN
344: sdst.sin_len = sizeof(sdst);
345: #endif
346: sdst.sin_addr.s_addr = dst;
347: if (sendto(igmp_socket, igmp_send_buf, sendlen, 0,
348: (struct sockaddr *)&sdst, sizeof(sdst)) < 0) {
349: if (errno == ENETDOWN)
350: check_vif_state();
351: else
352: log(log_level(IPPROTO_IGMP, type, code), errno,
353: "sendto to %s on %s", inet_fmt(dst, s1), inet_fmt(src, s2));
354: if (setloop)
355: k_set_loop(igmp_socket, FALSE);
356: return;
357: }
358:
359: if (setloop)
360: k_set_loop(igmp_socket, FALSE);
361:
362: IF_DEBUG(DEBUG_PKT|debug_kind(IPPROTO_IGMP, type, code))
363: log(LOG_DEBUG, 0, "SENT %s from %-15s to %s",
364: packet_kind(IPPROTO_IGMP, type, code),
365: src == INADDR_ANY_N ? "INADDR_ANY" :
366: inet_fmt(src, s1), inet_fmt(dst, s2));
367: }
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