xref: /openbsd/usr.sbin/tcpdump/print-dvmrp.c (revision 9b7c3dbb) 
1 /*	$OpenBSD: print-dvmrp.c,v 1.9 2015/11/16 00:16:39 mmcc Exp $	*/
2 
3 /*
4  * Copyright (c) 1995, 1996
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that: (1) source code distributions
9  * retain the above copyright notice and this paragraph in its entirety, (2)
10  * distributions including binary code include the above copyright notice and
11  * this paragraph in its entirety in the documentation or other materials
12  * provided with the distribution, and (3) all advertising materials mentioning
13  * features or use of this software display the following acknowledgement:
14  * ``This product includes software developed by the University of California,
15  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
16  * the University nor the names of its contributors may be used to endorse
17  * or promote products derived from this software without specific prior
18  * written permission.
19  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
20  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
21  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
22  */
23 
24 #include <sys/time.h>
25 #include <sys/socket.h>
26 
27 #include <netinet/in.h>
28 #include <netinet/ip.h>
29 #include <netinet/ip_var.h>
30 #include <netinet/udp.h>
31 #include <netinet/udp_var.h>
32 #include <netinet/tcp.h>
33 
34 #include <stdio.h>
35 #include <string.h>
36 #include <stdlib.h>
37 #include <unistd.h>
38 
39 #include "interface.h"
40 #include "addrtoname.h"
41 
42 /*
43  * DVMRP message types and flag values shamelessly stolen from
44  * mrouted/dvmrp.h.
45  */
46 #define DVMRP_PROBE		1	/* for finding neighbors */
47 #define DVMRP_REPORT		2	/* for reporting some or all routes */
48 #define DVMRP_ASK_NEIGHBORS	3	/* sent by mapper, asking for a list */
49 					/*
50 					 * of this router's neighbors
51 					 */
52 #define DVMRP_NEIGHBORS		4	/* response to such a request */
53 #define DVMRP_ASK_NEIGHBORS2	5	/* as above, want new format reply */
54 #define DVMRP_NEIGHBORS2	6
55 #define DVMRP_PRUNE		7	/* prune message */
56 #define DVMRP_GRAFT		8	/* graft message */
57 #define DVMRP_GRAFT_ACK		9	/* graft acknowledgement */
58 
59 /*
60  * 'flags' byte values in DVMRP_NEIGHBORS2 reply.
61  */
62 #define DVMRP_NF_TUNNEL		0x01	/* neighbors reached via tunnel */
63 #define DVMRP_NF_SRCRT		0x02	/* tunnel uses IP source routing */
64 #define DVMRP_NF_DOWN		0x10	/* kernel state of interface */
65 #define DVMRP_NF_DISABLED	0x20	/* administratively disabled */
66 #define DVMRP_NF_QUERIER	0x40	/* I am the subnet's querier */
67 
68 static void print_probe(const u_char *, const u_char *, u_int);
69 static void print_report(const u_char *, const u_char *, u_int);
70 static void print_neighbors(const u_char *, const u_char *, u_int);
71 static void print_neighbors2(const u_char *, const u_char *, u_int);
72 static void print_prune(const u_char *, const u_char *, u_int);
73 static void print_graft(const u_char *, const u_char *, u_int);
74 static void print_graft_ack(const u_char *, const u_char *, u_int);
75 
76 static u_int32_t target_level;
77 
78 void
79 dvmrp_print(const u_char *bp, u_int len)
80 {
81 	const u_char *ep;
82 	u_char type;
83 
84 	ep = (const u_char *)snapend;
85 	if (bp >= ep)
86 		return;
87 
88 	type = bp[1];
89 	bp += 8;
90 	/*
91 	 * Skip IGMP header
92 	 */
93 
94 	len -= 8;
95 
96 	switch (type) {
97 
98 	case DVMRP_PROBE:
99 		printf(" Probe");
100 		if (vflag)
101 			print_probe(bp, ep, len);
102 		break;
103 
104 	case DVMRP_REPORT:
105 		printf(" Report");
106 		if (vflag)
107 			print_report(bp, ep, len);
108 		break;
109 
110 	case DVMRP_ASK_NEIGHBORS:
111 		printf(" Ask-neighbors(old)");
112 		break;
113 
114 	case DVMRP_NEIGHBORS:
115 		printf(" Neighbors(old)");
116 		print_neighbors(bp, ep, len);
117 		break;
118 
119 	case DVMRP_ASK_NEIGHBORS2:
120 		printf(" Ask-neighbors2");
121 		break;
122 
123 	case DVMRP_NEIGHBORS2:
124 		printf(" Neighbors2");
125 		/*
126 		 * extract version and capabilities from IGMP group
127 		 * address field
128 		 */
129 		bp -= 4;
130 		target_level = (bp[0] << 24) | (bp[1] << 16) |
131 		    (bp[2] << 8) | bp[3];
132 		bp += 4;
133 		print_neighbors2(bp, ep, len);
134 		break;
135 
136 	case DVMRP_PRUNE:
137 		printf(" Prune");
138 		print_prune(bp, ep, len);
139 		break;
140 
141 	case DVMRP_GRAFT:
142 		printf(" Graft");
143 		print_graft(bp, ep, len);
144 		break;
145 
146 	case DVMRP_GRAFT_ACK:
147 		printf(" Graft-ACK");
148 		print_graft_ack(bp, ep, len);
149 		break;
150 
151 	default:
152 		printf(" [type %d]", type);
153 		break;
154 	}
155 }
156 
157 static void
158 print_report(const u_char *bp, const u_char *ep, u_int len)
159 {
160 	u_int32_t mask, origin;
161 	int metric, i, width, done;
162 
163 	while (len > 0) {
164 		if (len < 3) {
165 			printf(" [|]");
166 			return;
167 		}
168 		mask = (u_int32_t)0xff << 24 | bp[0] << 16 | bp[1] << 8 | bp[2];
169 		width = 1;
170 		if (bp[0])
171 			width = 2;
172 		if (bp[1])
173 			width = 3;
174 		if (bp[2])
175 			width = 4;
176 
177 		printf("\n\tMask %s", intoa(htonl(mask)));
178 		bp += 3;
179 		len -= 3;
180 		do {
181 			if (bp + width + 1 > ep) {
182 				printf(" [|]");
183 				return;
184 			}
185 			if (len < width + 1) {
186 				printf("\n\t  [Truncated Report]");
187 				return;
188 			}
189 			origin = 0;
190 			for (i = 0; i < width; ++i)
191 				origin = origin << 8 | *bp++;
192 			for ( ; i < 4; ++i)
193 				origin <<= 8;
194 
195 			metric = *bp++;
196 			done = metric & 0x80;
197 			metric &= 0x7f;
198 			printf("\n\t  %s metric %d", intoa(htonl(origin)),
199 				metric);
200 			len -= width + 1;
201 		} while (!done);
202 	}
203 }
204 
205 #define GET_ADDR(to) (memcpy((char *)to, (char *)bp, 4), bp += 4)
206 
207 static void
208 print_probe(const u_char *bp, const u_char *ep, u_int len)
209 {
210 	u_int32_t genid;
211 	u_char neighbor[4];
212 
213 	if ((len < 4) || ((bp + 4) > ep)) {
214 		/* { (ctags) */
215 		printf(" [|}");
216 		return;
217 	}
218 	genid = (bp[0] << 24) | (bp[1] << 16) | (bp[2] << 8) | bp[3];
219 	bp += 4;
220 	len -= 4;
221 	printf("\n\tgenid %u", genid);
222 
223 	while ((len > 0) && (bp < ep)) {
224 		if ((len < 4) || ((bp + 4) > ep)) {
225 			printf(" [|]");
226 			return;
227 		}
228 		GET_ADDR(neighbor);
229 		len -= 4;
230 		printf("\n\tneighbor %s", ipaddr_string(neighbor));
231 	}
232 }
233 
234 static void
235 print_neighbors(const u_char *bp, const u_char *ep, u_int len)
236 {
237 	u_char laddr[4], neighbor[4];
238 	u_char metric;
239 	u_char thresh;
240 	int ncount;
241 
242 	while (len > 0 && bp < ep) {
243 		if (len < 7 || (bp + 7) >= ep) {
244 			printf(" [|]");
245 			return;
246 		}
247 		GET_ADDR(laddr);
248 		metric = *bp++;
249 		thresh = *bp++;
250 		ncount = *bp++;
251 		len -= 7;
252 		while (--ncount >= 0 && (len >= 4) && (bp + 4) < ep) {
253 			GET_ADDR(neighbor);
254 			printf(" [%s ->", ipaddr_string(laddr));
255 			printf(" %s, (%d/%d)]",
256 				   ipaddr_string(neighbor), metric, thresh);
257 			len -= 4;
258 		}
259 	}
260 }
261 
262 static void
263 print_neighbors2(const u_char *bp, const u_char *ep, u_int len)
264 {
265 	u_char laddr[4], neighbor[4];
266 	u_char metric, thresh, flags;
267 	int ncount;
268 
269 	printf(" (v %d.%d):",
270 	       (int)target_level & 0xff,
271 	       (int)(target_level >> 8) & 0xff);
272 
273 	while (len > 0 && bp < ep) {
274 		if (len < 8 || (bp + 8) >= ep) {
275 			printf(" [|]");
276 			return;
277 		}
278 		GET_ADDR(laddr);
279 		metric = *bp++;
280 		thresh = *bp++;
281 		flags = *bp++;
282 		ncount = *bp++;
283 		len -= 8;
284 		while (--ncount >= 0 && (len >= 4) && (bp + 4) <= ep) {
285 			GET_ADDR(neighbor);
286 			printf(" [%s -> ", ipaddr_string(laddr));
287 			printf("%s (%d/%d", ipaddr_string(neighbor),
288 				     metric, thresh);
289 			if (flags & DVMRP_NF_TUNNEL)
290 				printf("/tunnel");
291 			if (flags & DVMRP_NF_SRCRT)
292 				printf("/srcrt");
293 			if (flags & DVMRP_NF_QUERIER)
294 				printf("/querier");
295 			if (flags & DVMRP_NF_DISABLED)
296 				printf("/disabled");
297 			if (flags & DVMRP_NF_DOWN)
298 				printf("/down");
299 			printf(")]");
300 			len -= 4;
301 		}
302 		if (ncount != -1) {
303 			printf(" [|]");
304 			return;
305 		}
306 	}
307 }
308 
309 static void
310 print_prune(const u_char *bp, const u_char *ep, u_int len)
311 {
312 	union a {
313 		u_char b[4];
314 		u_int32_t i;
315 	} prune_timer;
316 
317 	if (len < 12 || (bp + 12) > ep) {
318 		printf(" [|]");
319 		return;
320 	}
321 	printf(" src %s grp %s", ipaddr_string(bp), ipaddr_string(bp + 4));
322 	bp += 8;
323 	GET_ADDR(prune_timer.b);
324 	printf(" timer %d", (int)ntohl(prune_timer.i));
325 }
326 
327 static void
328 print_graft(const u_char *bp, const u_char *ep, u_int len)
329 {
330 
331 	if (len < 8 || (bp + 8) > ep) {
332 		printf(" [|]");
333 		return;
334 	}
335 	printf(" src %s grp %s", ipaddr_string(bp), ipaddr_string(bp + 4));
336 }
337 
338 static void
339 print_graft_ack(const u_char *bp, const u_char *ep, u_int len)
340 {
341 
342 	if (len < 8 || (bp + 8) > ep) {
343 		printf(" [|]");
344 		return;
345 	}
346 	printf(" src %s grp %s", ipaddr_string(bp), ipaddr_string(bp + 4));
347 }
348