The Tcpdump Group git mirrors - tcpdump/blob - print-dvmrp.c

   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
  51 /*
  52  * 'flags' byte values in DVMRP_NEIGHBORS2 reply.
  53  */
  54 #define DVMRP_NF_TUNNEL         0x01    /* neighbors reached via tunnel */
  55 #define DVMRP_NF_SRCRT          0x02    /* tunnel uses IP source routing */
  56 #define DVMRP_NF_DOWN           0x10    /* kernel state of interface */
  57 #define DVMRP_NF_DISABLED       0x20    /* administratively disabled */
  58 #define DVMRP_NF_QUERIER        0x40    /* I am the subnet's querier */
  59
  60 static int print_probe(netdissect_options *, const u_char *, const u_char *, u_int);
  61 static int print_report(netdissect_options *, const u_char *, const u_char *, u_int);
  62 static int print_neighbors(netdissect_options *, const u_char *, const u_char *, u_int);
  63 static int print_neighbors2(netdissect_options *, const u_char *, const u_char *, u_int, uint8_t, uint8_t);
  64 static int print_prune(netdissect_options *, const u_char *);
  65 static int print_graft(netdissect_options *, const u_char *);
  66 static int print_graft_ack(netdissect_options *, const u_char *);
  67
  68 void
  69 dvmrp_print(netdissect_options *ndo,
  70             const u_char *bp, u_int len)
  71 {
  72         const u_char *ep;
  73         u_char type;
  74         uint8_t major_version, minor_version;
  75
  76         ndo->ndo_protocol = "dvmrp";
  77         ep = ndo->ndo_snapend;
  78         if (bp >= ep)
  79                 return;
  80
  81         type = GET_U_1(bp + 1);
  82
  83         /* Skip IGMP header */
  84         bp += 8;
  85         len -= 8;
  86
  87         switch (type) {
  88
  89         case DVMRP_PROBE:
  90                 ND_PRINT(" Probe");
  91                 if (ndo->ndo_vflag) {
  92                         if (print_probe(ndo, bp, ep, len) < 0)
  93                                 goto trunc;
  94                 }
  95                 break;
  96
  97         case DVMRP_REPORT:
  98                 ND_PRINT(" Report");
  99                 if (ndo->ndo_vflag > 1) {
 100                         if (print_report(ndo, bp, ep, len) < 0)
 101                                 goto trunc;
 102                 }
 103                 break;
 104
 105         case DVMRP_ASK_NEIGHBORS:
 106                 ND_PRINT(" Ask-neighbors(old)");
 107                 break;
 108
 109         case DVMRP_NEIGHBORS:
 110                 ND_PRINT(" Neighbors(old)");
 111                 if (print_neighbors(ndo, bp, ep, len) < 0)
 112                         goto trunc;
 113                 break;
 114
 115         case DVMRP_ASK_NEIGHBORS2:
 116                 ND_PRINT(" Ask-neighbors2");
 117                 break;
 118
 119         case DVMRP_NEIGHBORS2:
 120                 ND_PRINT(" Neighbors2");
 121                 /*
 122                  * extract version from IGMP group address field
 123                  */
 124                 bp -= 4;
 125                 ND_TCHECK_4(bp);
 126                 major_version = GET_U_1(bp + 3);
 127                 minor_version = GET_U_1(bp + 2);
 128                 bp += 4;
 129                 if (print_neighbors2(ndo, bp, ep, len, major_version,
 130                     minor_version) < 0)
 131                         goto trunc;
 132                 break;
 133
 134         case DVMRP_PRUNE:
 135                 ND_PRINT(" Prune");
 136                 if (print_prune(ndo, bp) < 0)
 137                         goto trunc;
 138                 break;
 139
 140         case DVMRP_GRAFT:
 141                 ND_PRINT(" Graft");
 142                 if (print_graft(ndo, bp) < 0)
 143                         goto trunc;
 144                 break;
 145
 146         case DVMRP_GRAFT_ACK:
 147                 ND_PRINT(" Graft-ACK");
 148                 if (print_graft_ack(ndo, bp) < 0)
 149                         goto trunc;
 150                 break;
 151
 152         default:
 153                 ND_PRINT(" [type %u]", type);
 154                 break;
 155         }
 156         return;
 157
 158 trunc:
 159         nd_print_trunc(ndo);
 160         return;
 161 }
 162
 163 static int
 164 print_report(netdissect_options *ndo,
 165              const u_char *bp, const u_char *ep,
 166              u_int len)
 167 {
 168         uint32_t mask, origin;
 169         u_int metric, done;
 170         u_int i, width;
 171
 172         while (len > 0) {
 173                 if (len < 3) {
 174                         ND_PRINT(" [|]");
 175                         return (0);
 176                 }
 177                 ND_TCHECK_3(bp);
 178                 mask = (uint32_t)0xff << 24 | GET_U_1(bp) << 16 |
 179                         GET_U_1(bp + 1) << 8 | GET_U_1(bp + 2);
 180                 width = 1;
 181                 if (GET_U_1(bp))
 182                         width = 2;
 183                 if (GET_U_1(bp + 1))
 184                         width = 3;
 185                 if (GET_U_1(bp + 2))
 186                         width = 4;
 187
 188                 ND_PRINT("\n\tMask %s", intoa(htonl(mask)));
 189                 bp += 3;
 190                 len -= 3;
 191                 do {
 192                         if (bp + width + 1 > ep) {
 193                                 ND_PRINT(" [|]");
 194                                 return (0);
 195                         }
 196                         if (len < width + 1) {
 197                                 ND_PRINT("\n\t  [Truncated Report]");
 198                                 return (0);
 199                         }
 200                         origin = 0;
 201                         for (i = 0; i < width; ++i) {
 202                                 origin = origin << 8 | GET_U_1(bp);
 203                                 bp++;
 204                         }
 205                         for ( ; i < 4; ++i)
 206                                 origin <<= 8;
 207
 208                         metric = GET_U_1(bp);
 209                         bp++;
 210                         done = metric & 0x80;
 211                         metric &= 0x7f;
 212                         ND_PRINT("\n\t  %s metric %u", intoa(htonl(origin)),
 213                                 metric);
 214                         len -= width + 1;
 215                 } while (!done);
 216         }
 217         return (0);
 218 trunc:
 219         return (-1);
 220 }
 221
 222 static int
 223 print_probe(netdissect_options *ndo,
 224             const u_char *bp, const u_char *ep,
 225             u_int len)
 226 {
 227         uint32_t genid;
 228
 229         ND_TCHECK_4(bp);
 230         if ((len < 4) || ((bp + 4) > ep)) {
 231                 /* { (ctags) */
 232                 ND_PRINT(" [|}");
 233                 return (0);
 234         }
 235         genid = GET_BE_U_4(bp);
 236         bp += 4;
 237         len -= 4;
 238         ND_PRINT(ndo->ndo_vflag > 1 ? "\n\t" : " ");
 239         ND_PRINT("genid %u", genid);
 240         if (ndo->ndo_vflag < 2)
 241                 return (0);
 242
 243         while ((len > 0) && (bp < ep)) {
 244                 ND_TCHECK_4(bp);
 245                 ND_PRINT("\n\tneighbor %s", GET_IPADDR_STRING(bp));
 246                 bp += 4; len -= 4;
 247         }
 248         return (0);
 249 trunc:
 250         return (-1);
 251 }
 252
 253 static int
 254 print_neighbors(netdissect_options *ndo,
 255                 const u_char *bp, const u_char *ep,
 256                 u_int len)
 257 {
 258         const u_char *laddr;
 259         u_char metric;
 260         u_char thresh;
 261         int ncount;
 262
 263         while (len > 0 && bp < ep) {
 264                 ND_TCHECK_7(bp);
 265                 laddr = bp;
 266                 bp += 4;
 267                 metric = GET_U_1(bp);
 268                 bp++;
 269                 thresh = GET_U_1(bp);
 270                 bp++;
 271                 ncount = GET_U_1(bp);
 272                 bp++;
 273                 len -= 7;
 274                 while (--ncount >= 0) {
 275                         ND_TCHECK_4(bp);
 276                         ND_PRINT(" [%s ->", GET_IPADDR_STRING(laddr));
 277                         ND_PRINT(" %s, (%u/%u)]",
 278                                    GET_IPADDR_STRING(bp), metric, thresh);
 279                         bp += 4;
 280                         len -= 4;
 281                 }
 282         }
 283         return (0);
 284 trunc:
 285         return (-1);
 286 }
 287
 288 static int
 289 print_neighbors2(netdissect_options *ndo,
 290                  const u_char *bp, const u_char *ep,
 291                  u_int len, uint8_t major_version,
 292                  uint8_t minor_version)
 293 {
 294         const u_char *laddr;
 295         u_char metric, thresh, flags;
 296         int ncount;
 297
 298         ND_PRINT(" (v %u.%u):", major_version, minor_version);
 299
 300         while (len > 0 && bp < ep) {
 301                 ND_TCHECK_8(bp);
 302                 laddr = bp;
 303                 bp += 4;
 304                 metric = GET_U_1(bp);
 305                 bp++;
 306                 thresh = GET_U_1(bp);
 307                 bp++;
 308                 flags = GET_U_1(bp);
 309                 bp++;
 310                 ncount = GET_U_1(bp);
 311                 bp++;
 312                 len -= 8;
 313                 while (--ncount >= 0 && (len >= 4) && (bp + 4) <= ep) {
 314                         ND_PRINT(" [%s -> ", GET_IPADDR_STRING(laddr));
 315                         ND_PRINT("%s (%u/%u", GET_IPADDR_STRING(bp),
 316                                      metric, thresh);
 317                         if (flags & DVMRP_NF_TUNNEL)
 318                                 ND_PRINT("/tunnel");
 319                         if (flags & DVMRP_NF_SRCRT)
 320                                 ND_PRINT("/srcrt");
 321                         if (flags & DVMRP_NF_QUERIER)
 322                                 ND_PRINT("/querier");
 323                         if (flags & DVMRP_NF_DISABLED)
 324                                 ND_PRINT("/disabled");
 325                         if (flags & DVMRP_NF_DOWN)
 326                                 ND_PRINT("/down");
 327                         ND_PRINT(")]");
 328                         bp += 4;
 329                         len -= 4;
 330                 }
 331                 if (ncount != -1) {
 332                         ND_PRINT(" [|]");
 333                         return (0);
 334                 }
 335         }
 336         return (0);
 337 trunc:
 338         return (-1);
 339 }
 340
 341 static int
 342 print_prune(netdissect_options *ndo,
 343             const u_char *bp)
 344 {
 345         ND_TCHECK_LEN(bp, 12);
 346         ND_PRINT(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(bp + 4));
 347         bp += 8;
 348         ND_PRINT(" timer ");
 349         unsigned_relts_print(ndo, GET_BE_U_4(bp));
 350         return (0);
 351 trunc:
 352         return (-1);
 353 }
 354
 355 static int
 356 print_graft(netdissect_options *ndo,
 357             const u_char *bp)
 358 {
 359         ND_TCHECK_8(bp);
 360         ND_PRINT(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(bp + 4));
 361         return (0);
 362 trunc:
 363         return (-1);
 364 }
 365
 366 static int
 367 print_graft_ack(netdissect_options *ndo,
 368                 const u_char *bp)
 369 {
 370         ND_TCHECK_8(bp);
 371         ND_PRINT(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(bp + 4));
 372         return (0);
 373 trunc:
 374         return (-1);
 375 }