xref: /freebsd/contrib/tcpdump/print-dvmrp.c (revision b9f654b163bce26de79705e77b872427c9f2afa1)
1 /*
2  * Copyright (c) 1995, 1996
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that: (1) source code distributions
7  * retain the above copyright notice and this paragraph in its entirety, (2)
8  * distributions including binary code include the above copyright notice and
9  * this paragraph in its entirety in the documentation or other materials
10  * provided with the distribution, and (3) all advertising materials mentioning
11  * features or use of this software display the following acknowledgement:
12  * ``This product includes software developed by the University of California,
13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14  * the University nor the names of its contributors may be used to endorse
15  * or promote products derived from this software without specific prior
16  * written permission.
17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20  */
21 
22 /* \summary: Distance Vector Multicast Routing Protocol printer */
23 
24 #ifdef HAVE_CONFIG_H
25 #include "config.h"
26 #endif
27 
28 #include <netdissect-stdinc.h>
29 
30 #include "netdissect.h"
31 #include "extract.h"
32 #include "addrtoname.h"
33 
34 /*
35  * DVMRP message types and flag values shamelessly stolen from
36  * mrouted/dvmrp.h.
37  */
38 #define DVMRP_PROBE		1	/* for finding neighbors */
39 #define DVMRP_REPORT		2	/* for reporting some or all routes */
40 #define DVMRP_ASK_NEIGHBORS	3	/* sent by mapper, asking for a list */
41 					/* of this router's neighbors */
42 #define DVMRP_NEIGHBORS		4	/* response to such a request */
43 #define DVMRP_ASK_NEIGHBORS2	5	/* as above, want new format reply */
44 #define DVMRP_NEIGHBORS2	6
45 #define DVMRP_PRUNE		7	/* prune message */
46 #define DVMRP_GRAFT		8	/* graft message */
47 #define DVMRP_GRAFT_ACK		9	/* graft acknowledgement */
48 
49 /*
50  * 'flags' byte values in DVMRP_NEIGHBORS2 reply.
51  */
52 #define DVMRP_NF_TUNNEL		0x01	/* neighbors reached via tunnel */
53 #define DVMRP_NF_SRCRT		0x02	/* tunnel uses IP source routing */
54 #define DVMRP_NF_DOWN		0x10	/* kernel state of interface */
55 #define DVMRP_NF_DISABLED	0x20	/* administratively disabled */
56 #define DVMRP_NF_QUERIER	0x40	/* I am the subnet's querier */
57 
58 static int print_probe(netdissect_options *, const u_char *, const u_char *, u_int);
59 static int print_report(netdissect_options *, const u_char *, const u_char *, u_int);
60 static int print_neighbors(netdissect_options *, const u_char *, const u_char *, u_int);
61 static int print_neighbors2(netdissect_options *, const u_char *, const u_char *, u_int);
62 static int print_prune(netdissect_options *, const u_char *);
63 static int print_graft(netdissect_options *, const u_char *);
64 static int print_graft_ack(netdissect_options *, const u_char *);
65 
66 static uint32_t target_level;
67 
68 void
69 dvmrp_print(netdissect_options *ndo,
70             register const u_char *bp, register u_int len)
71 {
72 	register const u_char *ep;
73 	register u_char type;
74 
75 	ep = (const u_char *)ndo->ndo_snapend;
76 	if (bp >= ep)
77 		return;
78 
79 	ND_TCHECK(bp[1]);
80 	type = bp[1];
81 
82 	/* Skip IGMP header */
83 	bp += 8;
84 	len -= 8;
85 
86 	switch (type) {
87 
88 	case DVMRP_PROBE:
89 		ND_PRINT((ndo, " Probe"));
90 		if (ndo->ndo_vflag) {
91 			if (print_probe(ndo, bp, ep, len) < 0)
92 				goto trunc;
93 		}
94 		break;
95 
96 	case DVMRP_REPORT:
97 		ND_PRINT((ndo, " Report"));
98 		if (ndo->ndo_vflag > 1) {
99 			if (print_report(ndo, bp, ep, len) < 0)
100 				goto trunc;
101 		}
102 		break;
103 
104 	case DVMRP_ASK_NEIGHBORS:
105 		ND_PRINT((ndo, " Ask-neighbors(old)"));
106 		break;
107 
108 	case DVMRP_NEIGHBORS:
109 		ND_PRINT((ndo, " Neighbors(old)"));
110 		if (print_neighbors(ndo, bp, ep, len) < 0)
111 			goto trunc;
112 		break;
113 
114 	case DVMRP_ASK_NEIGHBORS2:
115 		ND_PRINT((ndo, " Ask-neighbors2"));
116 		break;
117 
118 	case DVMRP_NEIGHBORS2:
119 		ND_PRINT((ndo, " Neighbors2"));
120 		/*
121 		 * extract version and capabilities from IGMP group
122 		 * address field
123 		 */
124 		bp -= 4;
125 		ND_TCHECK2(bp[0], 4);
126 		target_level = (bp[0] << 24) | (bp[1] << 16) |
127 		    (bp[2] << 8) | bp[3];
128 		bp += 4;
129 		if (print_neighbors2(ndo, bp, ep, len) < 0)
130 			goto trunc;
131 		break;
132 
133 	case DVMRP_PRUNE:
134 		ND_PRINT((ndo, " Prune"));
135 		if (print_prune(ndo, bp) < 0)
136 			goto trunc;
137 		break;
138 
139 	case DVMRP_GRAFT:
140 		ND_PRINT((ndo, " Graft"));
141 		if (print_graft(ndo, bp) < 0)
142 			goto trunc;
143 		break;
144 
145 	case DVMRP_GRAFT_ACK:
146 		ND_PRINT((ndo, " Graft-ACK"));
147 		if (print_graft_ack(ndo, bp) < 0)
148 			goto trunc;
149 		break;
150 
151 	default:
152 		ND_PRINT((ndo, " [type %d]", type));
153 		break;
154 	}
155 	return;
156 
157 trunc:
158 	ND_PRINT((ndo, "[|dvmrp]"));
159 	return;
160 }
161 
162 static int
163 print_report(netdissect_options *ndo,
164              register const u_char *bp, register const u_char *ep,
165              register u_int len)
166 {
167 	register uint32_t mask, origin;
168 	register int metric, done;
169 	register u_int i, width;
170 
171 	while (len > 0) {
172 		if (len < 3) {
173 			ND_PRINT((ndo, " [|]"));
174 			return (0);
175 		}
176 		ND_TCHECK2(bp[0], 3);
177 		mask = (uint32_t)0xff << 24 | bp[0] << 16 | bp[1] << 8 | bp[2];
178 		width = 1;
179 		if (bp[0])
180 			width = 2;
181 		if (bp[1])
182 			width = 3;
183 		if (bp[2])
184 			width = 4;
185 
186 		ND_PRINT((ndo, "\n\tMask %s", intoa(htonl(mask))));
187 		bp += 3;
188 		len -= 3;
189 		do {
190 			if (bp + width + 1 > ep) {
191 				ND_PRINT((ndo, " [|]"));
192 				return (0);
193 			}
194 			if (len < width + 1) {
195 				ND_PRINT((ndo, "\n\t  [Truncated Report]"));
196 				return (0);
197 			}
198 			origin = 0;
199 			for (i = 0; i < width; ++i) {
200 				ND_TCHECK(*bp);
201 				origin = origin << 8 | *bp++;
202 			}
203 			for ( ; i < 4; ++i)
204 				origin <<= 8;
205 
206 			ND_TCHECK(*bp);
207 			metric = *bp++;
208 			done = metric & 0x80;
209 			metric &= 0x7f;
210 			ND_PRINT((ndo, "\n\t  %s metric %d", intoa(htonl(origin)),
211 				metric));
212 			len -= width + 1;
213 		} while (!done);
214 	}
215 	return (0);
216 trunc:
217 	return (-1);
218 }
219 
220 static int
221 print_probe(netdissect_options *ndo,
222             register const u_char *bp, register const u_char *ep,
223             register u_int len)
224 {
225 	register uint32_t genid;
226 
227 	ND_TCHECK2(bp[0], 4);
228 	if ((len < 4) || ((bp + 4) > ep)) {
229 		/* { (ctags) */
230 		ND_PRINT((ndo, " [|}"));
231 		return (0);
232 	}
233 	genid = (bp[0] << 24) | (bp[1] << 16) | (bp[2] << 8) | bp[3];
234 	bp += 4;
235 	len -= 4;
236 	ND_PRINT((ndo, ndo->ndo_vflag > 1 ? "\n\t" : " "));
237 	ND_PRINT((ndo, "genid %u", genid));
238 	if (ndo->ndo_vflag < 2)
239 		return (0);
240 
241 	while ((len > 0) && (bp < ep)) {
242 		ND_TCHECK2(bp[0], 4);
243 		ND_PRINT((ndo, "\n\tneighbor %s", ipaddr_string(ndo, bp)));
244 		bp += 4; len -= 4;
245 	}
246 	return (0);
247 trunc:
248 	return (-1);
249 }
250 
251 static int
252 print_neighbors(netdissect_options *ndo,
253                 register const u_char *bp, register const u_char *ep,
254                 register u_int len)
255 {
256 	const u_char *laddr;
257 	register u_char metric;
258 	register u_char thresh;
259 	register int ncount;
260 
261 	while (len > 0 && bp < ep) {
262 		ND_TCHECK2(bp[0], 7);
263 		laddr = bp;
264 		bp += 4;
265 		metric = *bp++;
266 		thresh = *bp++;
267 		ncount = *bp++;
268 		len -= 7;
269 		while (--ncount >= 0) {
270 			ND_TCHECK2(bp[0], 4);
271 			ND_PRINT((ndo, " [%s ->", ipaddr_string(ndo, laddr)));
272 			ND_PRINT((ndo, " %s, (%d/%d)]",
273 				   ipaddr_string(ndo, bp), metric, thresh));
274 			bp += 4;
275 			len -= 4;
276 		}
277 	}
278 	return (0);
279 trunc:
280 	return (-1);
281 }
282 
283 static int
284 print_neighbors2(netdissect_options *ndo,
285                  register const u_char *bp, register const u_char *ep,
286                  register u_int len)
287 {
288 	const u_char *laddr;
289 	register u_char metric, thresh, flags;
290 	register int ncount;
291 
292 	ND_PRINT((ndo, " (v %d.%d):",
293 	       (int)target_level & 0xff,
294 	       (int)(target_level >> 8) & 0xff));
295 
296 	while (len > 0 && bp < ep) {
297 		ND_TCHECK2(bp[0], 8);
298 		laddr = bp;
299 		bp += 4;
300 		metric = *bp++;
301 		thresh = *bp++;
302 		flags = *bp++;
303 		ncount = *bp++;
304 		len -= 8;
305 		while (--ncount >= 0 && (len >= 4) && (bp + 4) <= ep) {
306 			ND_PRINT((ndo, " [%s -> ", ipaddr_string(ndo, laddr)));
307 			ND_PRINT((ndo, "%s (%d/%d", ipaddr_string(ndo, bp),
308 				     metric, thresh));
309 			if (flags & DVMRP_NF_TUNNEL)
310 				ND_PRINT((ndo, "/tunnel"));
311 			if (flags & DVMRP_NF_SRCRT)
312 				ND_PRINT((ndo, "/srcrt"));
313 			if (flags & DVMRP_NF_QUERIER)
314 				ND_PRINT((ndo, "/querier"));
315 			if (flags & DVMRP_NF_DISABLED)
316 				ND_PRINT((ndo, "/disabled"));
317 			if (flags & DVMRP_NF_DOWN)
318 				ND_PRINT((ndo, "/down"));
319 			ND_PRINT((ndo, ")]"));
320 			bp += 4;
321 			len -= 4;
322 		}
323 		if (ncount != -1) {
324 			ND_PRINT((ndo, " [|]"));
325 			return (0);
326 		}
327 	}
328 	return (0);
329 trunc:
330 	return (-1);
331 }
332 
333 static int
334 print_prune(netdissect_options *ndo,
335             register const u_char *bp)
336 {
337 	ND_TCHECK2(bp[0], 12);
338 	ND_PRINT((ndo, " src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4)));
339 	bp += 8;
340 	ND_PRINT((ndo, " timer "));
341 	unsigned_relts_print(ndo, EXTRACT_32BITS(bp));
342 	return (0);
343 trunc:
344 	return (-1);
345 }
346 
347 static int
348 print_graft(netdissect_options *ndo,
349             register const u_char *bp)
350 {
351 	ND_TCHECK2(bp[0], 8);
352 	ND_PRINT((ndo, " src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4)));
353 	return (0);
354 trunc:
355 	return (-1);
356 }
357 
358 static int
359 print_graft_ack(netdissect_options *ndo,
360                 register const u_char *bp)
361 {
362 	ND_TCHECK2(bp[0], 8);
363 	ND_PRINT((ndo, " src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4)));
364 	return (0);
365 trunc:
366 	return (-1);
367 }
368