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 * See: RFC 1075 and draft-ietf-idmr-dvmrp-v3
36 *
37 * DVMRP message types and flag values shamelessly stolen from
38 * mrouted/dvmrp.h.
39 */
40#define DVMRP_PROBE		1	/* for finding neighbors */
41#define DVMRP_REPORT		2	/* for reporting some or all routes */
42#define DVMRP_ASK_NEIGHBORS	3	/* sent by mapper, asking for a list */
43					/* of this router's neighbors */
44#define DVMRP_NEIGHBORS		4	/* response to such a request */
45#define DVMRP_ASK_NEIGHBORS2	5	/* as above, want new format reply */
46#define DVMRP_NEIGHBORS2	6
47#define DVMRP_PRUNE		7	/* prune message */
48#define DVMRP_GRAFT		8	/* graft message */
49#define DVMRP_GRAFT_ACK		9	/* graft acknowledgement */
50static const struct tok dvmrp_msgtype_str[] = {
51	{ DVMRP_PROBE,          "Probe"              },
52	{ DVMRP_REPORT,         "Report"             },
53	{ DVMRP_ASK_NEIGHBORS,  "Ask-neighbors(old)" },
54	{ DVMRP_NEIGHBORS,      "Neighbors(old)"     },
55	{ DVMRP_ASK_NEIGHBORS2, "Ask-neighbors2"     },
56	{ DVMRP_NEIGHBORS2,     "Neighbors2"         },
57	{ DVMRP_PRUNE,          "Prune"              },
58	{ DVMRP_GRAFT,          "Graft"              },
59	{ DVMRP_GRAFT_ACK,      "Graft-ACK"          },
60	{ 0, NULL }
61};
62
63/*
64 * 'flags' byte values in DVMRP_NEIGHBORS2 reply.
65 */
66#define DVMRP_NF_TUNNEL		0x01	/* neighbors reached via tunnel */
67#define DVMRP_NF_SRCRT		0x02	/* tunnel uses IP source routing */
68#define DVMRP_NF_DOWN		0x10	/* kernel state of interface */
69#define DVMRP_NF_DISABLED	0x20	/* administratively disabled */
70#define DVMRP_NF_QUERIER	0x40	/* I am the subnet's querier */
71
72static void print_probe(netdissect_options *, const u_char *, u_int);
73static void print_report(netdissect_options *, const u_char *, u_int);
74static void print_neighbors(netdissect_options *, const u_char *, u_int);
75static void print_neighbors2(netdissect_options *, const u_char *, u_int, uint8_t, uint8_t);
76
77void
78dvmrp_print(netdissect_options *ndo,
79            const u_char *bp, u_int len)
80{
81	u_char type;
82	uint8_t major_version, minor_version;
83
84	ndo->ndo_protocol = "dvmrp";
85	if (len < 8) {
86		ND_PRINT(" [length %u < 8]", len);
87		goto invalid;
88	}
89
90	type = GET_U_1(bp + 1);
91
92	/* Skip IGMP header */
93	bp += 8;
94	len -= 8;
95
96	ND_PRINT(" %s", tok2str(dvmrp_msgtype_str, "[type %u]", type));
97	switch (type) {
98
99	case DVMRP_PROBE:
100		if (ndo->ndo_vflag) {
101			print_probe(ndo, bp, len);
102		}
103		break;
104
105	case DVMRP_REPORT:
106		if (ndo->ndo_vflag > 1) {
107			print_report(ndo, bp, len);
108		}
109		break;
110
111	case DVMRP_NEIGHBORS:
112		print_neighbors(ndo, bp, len);
113		break;
114
115	case DVMRP_NEIGHBORS2:
116		/*
117		 * extract version from IGMP group address field
118		 */
119		bp -= 4;
120		major_version = GET_U_1(bp + 3);
121		minor_version = GET_U_1(bp + 2);
122		bp += 4;
123		print_neighbors2(ndo, bp, len, major_version, minor_version);
124		break;
125
126	case DVMRP_PRUNE:
127		ND_PRINT(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(bp + 4));
128		ND_PRINT(" timer ");
129		unsigned_relts_print(ndo, GET_BE_U_4(bp + 8));
130		break;
131
132	case DVMRP_GRAFT:
133		ND_PRINT(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(bp + 4));
134		break;
135
136	case DVMRP_GRAFT_ACK:
137		ND_PRINT(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(bp + 4));
138		break;
139	}
140	return;
141
142invalid:
143	nd_print_invalid(ndo);
144}
145
146static void
147print_report(netdissect_options *ndo,
148             const u_char *bp,
149             u_int len)
150{
151	uint32_t mask, origin;
152	u_int metric, done;
153	u_int i, width;
154
155	while (len > 0) {
156		if (len < 3) {
157			ND_PRINT(" [length %u < 3]", len);
158			goto invalid;
159		}
160		mask = (uint32_t)0xff << 24 | GET_U_1(bp) << 16 |
161			GET_U_1(bp + 1) << 8 | GET_U_1(bp + 2);
162		width = 1;
163		if (GET_U_1(bp))
164			width = 2;
165		if (GET_U_1(bp + 1))
166			width = 3;
167		if (GET_U_1(bp + 2))
168			width = 4;
169
170		ND_PRINT("\n\tMask %s", intoa(htonl(mask)));
171		bp += 3;
172		len -= 3;
173		do {
174			if (len < width + 1) {
175				ND_PRINT("\n\t  [Truncated Report]");
176				goto invalid;
177			}
178			origin = 0;
179			for (i = 0; i < width; ++i) {
180				origin = origin << 8 | GET_U_1(bp);
181				bp++;
182			}
183			for ( ; i < 4; ++i)
184				origin <<= 8;
185
186			metric = GET_U_1(bp);
187			bp++;
188			done = metric & 0x80;
189			metric &= 0x7f;
190			ND_PRINT("\n\t  %s metric %u", intoa(htonl(origin)),
191				metric);
192			len -= width + 1;
193		} while (!done);
194	}
195	return;
196
197invalid:
198	nd_print_invalid(ndo);
199}
200
201static void
202print_probe(netdissect_options *ndo,
203            const u_char *bp,
204            u_int len)
205{
206	if (len < 4) {
207		ND_PRINT(" [full length %u < 4]", len);
208		goto invalid;
209	}
210	ND_PRINT(ndo->ndo_vflag > 1 ? "\n\t" : " ");
211	ND_PRINT("genid %u", GET_BE_U_4(bp));
212	if (ndo->ndo_vflag < 2)
213		return;
214
215	bp += 4;
216	len -= 4;
217	while (len > 0) {
218		if (len < 4) {
219			ND_PRINT("[remaining length %u < 4]", len);
220			goto invalid;
221		}
222		ND_PRINT("\n\tneighbor %s", GET_IPADDR_STRING(bp));
223		bp += 4; len -= 4;
224	}
225	return;
226
227invalid:
228	nd_print_invalid(ndo);
229}
230
231static void
232print_neighbors(netdissect_options *ndo,
233                const u_char *bp,
234                u_int len)
235{
236	const u_char *laddr;
237	u_char metric;
238	u_char thresh;
239	int ncount;
240
241	while (len > 0) {
242		if (len < 7) {
243			ND_PRINT(" [length %u < 7]", len);
244			goto invalid;
245		}
246		laddr = bp;
247		bp += 4;
248		metric = GET_U_1(bp);
249		bp++;
250		thresh = GET_U_1(bp);
251		bp++;
252		ncount = GET_U_1(bp);
253		bp++;
254		len -= 7;
255		while (--ncount >= 0) {
256			if (len < 4) {
257				ND_PRINT(" [length %u < 4]", len);
258				goto invalid;
259			}
260			ND_PRINT(" [%s ->", GET_IPADDR_STRING(laddr));
261			ND_PRINT(" %s, (%u/%u)]",
262				   GET_IPADDR_STRING(bp), metric, thresh);
263			bp += 4;
264			len -= 4;
265		}
266	}
267	return;
268
269invalid:
270	nd_print_invalid(ndo);
271}
272
273static void
274print_neighbors2(netdissect_options *ndo,
275                 const u_char *bp,
276                 u_int len, uint8_t major_version,
277                 uint8_t minor_version)
278{
279	const u_char *laddr;
280	u_char metric, thresh, flags;
281	int ncount;
282
283	ND_PRINT(" (v %u.%u):", major_version, minor_version);
284
285	while (len > 0) {
286		if (len < 8) {
287			ND_PRINT(" [length %u < 8]", len);
288			goto invalid;
289		}
290		laddr = bp;
291		bp += 4;
292		metric = GET_U_1(bp);
293		bp++;
294		thresh = GET_U_1(bp);
295		bp++;
296		flags = GET_U_1(bp);
297		bp++;
298		ncount = GET_U_1(bp);
299		bp++;
300		len -= 8;
301		while (--ncount >= 0 && len > 0) {
302			if (len < 4) {
303				ND_PRINT(" [length %u < 4]", len);
304				goto invalid;
305			}
306			ND_PRINT(" [%s -> ", GET_IPADDR_STRING(laddr));
307			ND_PRINT("%s (%u/%u", GET_IPADDR_STRING(bp),
308				     metric, thresh);
309			if (flags & DVMRP_NF_TUNNEL)
310				ND_PRINT("/tunnel");
311			if (flags & DVMRP_NF_SRCRT)
312				ND_PRINT("/srcrt");
313			if (flags & DVMRP_NF_QUERIER)
314				ND_PRINT("/querier");
315			if (flags & DVMRP_NF_DISABLED)
316				ND_PRINT("/disabled");
317			if (flags & DVMRP_NF_DOWN)
318				ND_PRINT("/down");
319			ND_PRINT(")]");
320			bp += 4;
321			len -= 4;
322		}
323		if (ncount != -1) {
324			ND_PRINT(" [invalid ncount]");
325			goto invalid;
326		}
327	}
328	return;
329
330invalid:
331	nd_print_invalid(ndo);
332}
333