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 */
50 static 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
72 static void print_probe(netdissect_options *, const u_char *, u_int);
73 static void print_report(netdissect_options *, const u_char *, u_int);
74 static void print_neighbors(netdissect_options *, const u_char *, u_int);
75 static void print_neighbors2(netdissect_options *, const u_char *, u_int, uint8_t, uint8_t);
76
77 void
dvmrp_print(netdissect_options * ndo,const u_char * bp,u_int len)78 dvmrp_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
142 invalid:
143 nd_print_invalid(ndo);
144 }
145
146 static void
print_report(netdissect_options * ndo,const u_char * bp,u_int len)147 print_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
197 invalid:
198 nd_print_invalid(ndo);
199 }
200
201 static void
print_probe(netdissect_options * ndo,const u_char * bp,u_int len)202 print_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
227 invalid:
228 nd_print_invalid(ndo);
229 }
230
231 static void
print_neighbors(netdissect_options * ndo,const u_char * bp,u_int len)232 print_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
269 invalid:
270 nd_print_invalid(ndo);
271 }
272
273 static void
print_neighbors2(netdissect_options * ndo,const u_char * bp,u_int len,uint8_t major_version,uint8_t minor_version)274 print_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
330 invalid:
331 nd_print_invalid(ndo);
332 }
333