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 #include <config.h>
25
26 #include "netdissect-stdinc.h"
27
28 #include "netdissect.h"
29 #include "extract.h"
30 #include "addrtoname.h"
31
32 /*
33 * See: RFC 1075 and draft-ietf-idmr-dvmrp-v3
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 static const struct tok dvmrp_msgtype_str[] = {
49 { DVMRP_PROBE, "Probe" },
50 { DVMRP_REPORT, "Report" },
51 { DVMRP_ASK_NEIGHBORS, "Ask-neighbors(old)" },
52 { DVMRP_NEIGHBORS, "Neighbors(old)" },
53 { DVMRP_ASK_NEIGHBORS2, "Ask-neighbors2" },
54 { DVMRP_NEIGHBORS2, "Neighbors2" },
55 { DVMRP_PRUNE, "Prune" },
56 { DVMRP_GRAFT, "Graft" },
57 { DVMRP_GRAFT_ACK, "Graft-ACK" },
58 { 0, NULL }
59 };
60
61 /*
62 * 'flags' byte values in DVMRP_NEIGHBORS2 reply.
63 */
64 #define DVMRP_NF_TUNNEL 0x01 /* neighbors reached via tunnel */
65 #define DVMRP_NF_SRCRT 0x02 /* tunnel uses IP source routing */
66 #define DVMRP_NF_DOWN 0x10 /* kernel state of interface */
67 #define DVMRP_NF_DISABLED 0x20 /* administratively disabled */
68 #define DVMRP_NF_QUERIER 0x40 /* I am the subnet's querier */
69
70 static void print_probe(netdissect_options *, const u_char *, u_int);
71 static void print_report(netdissect_options *, const u_char *, u_int);
72 static void print_neighbors(netdissect_options *, const u_char *, u_int);
73 static void print_neighbors2(netdissect_options *, const u_char *, u_int, uint8_t, uint8_t);
74
75 void
dvmrp_print(netdissect_options * ndo,const u_char * bp,u_int len)76 dvmrp_print(netdissect_options *ndo,
77 const u_char *bp, u_int len)
78 {
79 u_char type;
80 uint8_t major_version, minor_version;
81
82 ndo->ndo_protocol = "dvmrp";
83 if (len < 8) {
84 ND_PRINT(" [length %u < 8]", len);
85 goto invalid;
86 }
87
88 type = GET_U_1(bp + 1);
89
90 /* Skip IGMP header */
91 bp += 8;
92 len -= 8;
93
94 ND_PRINT(" %s", tok2str(dvmrp_msgtype_str, "[type %u]", type));
95 switch (type) {
96
97 case DVMRP_PROBE:
98 if (ndo->ndo_vflag) {
99 print_probe(ndo, bp, len);
100 }
101 break;
102
103 case DVMRP_REPORT:
104 if (ndo->ndo_vflag > 1) {
105 print_report(ndo, bp, len);
106 }
107 break;
108
109 case DVMRP_NEIGHBORS:
110 print_neighbors(ndo, bp, len);
111 break;
112
113 case DVMRP_NEIGHBORS2:
114 /*
115 * extract version from IGMP group address field
116 */
117 bp -= 4;
118 major_version = GET_U_1(bp + 3);
119 minor_version = GET_U_1(bp + 2);
120 bp += 4;
121 print_neighbors2(ndo, bp, len, major_version, minor_version);
122 break;
123
124 case DVMRP_PRUNE:
125 ND_PRINT(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(bp + 4));
126 ND_PRINT(" timer ");
127 unsigned_relts_print(ndo, GET_BE_U_4(bp + 8));
128 break;
129
130 case DVMRP_GRAFT:
131 ND_PRINT(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(bp + 4));
132 break;
133
134 case DVMRP_GRAFT_ACK:
135 ND_PRINT(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(bp + 4));
136 break;
137 }
138 return;
139
140 invalid:
141 nd_print_invalid(ndo);
142 }
143
144 static void
print_report(netdissect_options * ndo,const u_char * bp,u_int len)145 print_report(netdissect_options *ndo,
146 const u_char *bp,
147 u_int len)
148 {
149 uint32_t mask, origin;
150 u_int metric, done;
151 u_int i, width;
152
153 while (len > 0) {
154 if (len < 3) {
155 ND_PRINT(" [length %u < 3]", len);
156 goto invalid;
157 }
158 mask = (uint32_t)0xff << 24 | GET_U_1(bp) << 16 |
159 GET_U_1(bp + 1) << 8 | GET_U_1(bp + 2);
160 width = 1;
161 if (GET_U_1(bp))
162 width = 2;
163 if (GET_U_1(bp + 1))
164 width = 3;
165 if (GET_U_1(bp + 2))
166 width = 4;
167
168 ND_PRINT("\n\tMask %s", intoa(htonl(mask)));
169 bp += 3;
170 len -= 3;
171 do {
172 if (len < width + 1) {
173 ND_PRINT("\n\t [Truncated Report]");
174 goto invalid;
175 }
176 origin = 0;
177 for (i = 0; i < width; ++i) {
178 origin = origin << 8 | GET_U_1(bp);
179 bp++;
180 }
181 for ( ; i < 4; ++i)
182 origin <<= 8;
183
184 metric = GET_U_1(bp);
185 bp++;
186 done = metric & 0x80;
187 metric &= 0x7f;
188 ND_PRINT("\n\t %s metric %u", intoa(htonl(origin)),
189 metric);
190 len -= width + 1;
191 } while (!done);
192 }
193 return;
194
195 invalid:
196 nd_print_invalid(ndo);
197 }
198
199 static void
print_probe(netdissect_options * ndo,const u_char * bp,u_int len)200 print_probe(netdissect_options *ndo,
201 const u_char *bp,
202 u_int len)
203 {
204 if (len < 4) {
205 ND_PRINT(" [full length %u < 4]", len);
206 goto invalid;
207 }
208 ND_PRINT(ndo->ndo_vflag > 1 ? "\n\t" : " ");
209 ND_PRINT("genid %u", GET_BE_U_4(bp));
210 if (ndo->ndo_vflag < 2)
211 return;
212
213 bp += 4;
214 len -= 4;
215 while (len > 0) {
216 if (len < 4) {
217 ND_PRINT("[remaining length %u < 4]", len);
218 goto invalid;
219 }
220 ND_PRINT("\n\tneighbor %s", GET_IPADDR_STRING(bp));
221 bp += 4; len -= 4;
222 }
223 return;
224
225 invalid:
226 nd_print_invalid(ndo);
227 }
228
229 static void
print_neighbors(netdissect_options * ndo,const u_char * bp,u_int len)230 print_neighbors(netdissect_options *ndo,
231 const u_char *bp,
232 u_int len)
233 {
234 const u_char *laddr;
235 u_char metric;
236 u_char thresh;
237 int ncount;
238
239 while (len > 0) {
240 if (len < 7) {
241 ND_PRINT(" [length %u < 7]", len);
242 goto invalid;
243 }
244 laddr = bp;
245 bp += 4;
246 metric = GET_U_1(bp);
247 bp++;
248 thresh = GET_U_1(bp);
249 bp++;
250 ncount = GET_U_1(bp);
251 bp++;
252 len -= 7;
253 while (--ncount >= 0) {
254 if (len < 4) {
255 ND_PRINT(" [length %u < 4]", len);
256 goto invalid;
257 }
258 ND_PRINT(" [%s ->", GET_IPADDR_STRING(laddr));
259 ND_PRINT(" %s, (%u/%u)]",
260 GET_IPADDR_STRING(bp), metric, thresh);
261 bp += 4;
262 len -= 4;
263 }
264 }
265 return;
266
267 invalid:
268 nd_print_invalid(ndo);
269 }
270
271 static void
print_neighbors2(netdissect_options * ndo,const u_char * bp,u_int len,uint8_t major_version,uint8_t minor_version)272 print_neighbors2(netdissect_options *ndo,
273 const u_char *bp,
274 u_int len, uint8_t major_version,
275 uint8_t minor_version)
276 {
277 const u_char *laddr;
278 u_char metric, thresh, flags;
279 int ncount;
280
281 ND_PRINT(" (v %u.%u):", major_version, minor_version);
282
283 while (len > 0) {
284 if (len < 8) {
285 ND_PRINT(" [length %u < 8]", len);
286 goto invalid;
287 }
288 laddr = bp;
289 bp += 4;
290 metric = GET_U_1(bp);
291 bp++;
292 thresh = GET_U_1(bp);
293 bp++;
294 flags = GET_U_1(bp);
295 bp++;
296 ncount = GET_U_1(bp);
297 bp++;
298 len -= 8;
299 while (--ncount >= 0 && len > 0) {
300 if (len < 4) {
301 ND_PRINT(" [length %u < 4]", len);
302 goto invalid;
303 }
304 ND_PRINT(" [%s -> ", GET_IPADDR_STRING(laddr));
305 ND_PRINT("%s (%u/%u", GET_IPADDR_STRING(bp),
306 metric, thresh);
307 if (flags & DVMRP_NF_TUNNEL)
308 ND_PRINT("/tunnel");
309 if (flags & DVMRP_NF_SRCRT)
310 ND_PRINT("/srcrt");
311 if (flags & DVMRP_NF_QUERIER)
312 ND_PRINT("/querier");
313 if (flags & DVMRP_NF_DISABLED)
314 ND_PRINT("/disabled");
315 if (flags & DVMRP_NF_DOWN)
316 ND_PRINT("/down");
317 ND_PRINT(")]");
318 bp += 4;
319 len -= 4;
320 }
321 if (ncount != -1) {
322 ND_PRINT(" [ncount %d]", ncount);
323 goto invalid;
324 }
325 }
326 return;
327
328 invalid:
329 nd_print_invalid(ndo);
330 }
331