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 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
  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
 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
 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
 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
 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(" [ncount %d]", ncount);
 325                         goto invalid;
 326                 }
 327         }
 328         return;
 329
 330 invalid:
 331         nd_print_invalid(ndo);
 332 }