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         ep = (const u_char *)ndo->ndo_snapend;
  77         if (bp >= ep)
  78                 return;
  79
  80         ND_TCHECK_1(bp + 1);
  81         type = EXTRACT_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((ndo, " 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((ndo, " 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((ndo, " Ask-neighbors(old)"));
 107                 break;
 108
 109         case DVMRP_NEIGHBORS:
 110                 ND_PRINT((ndo, " 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((ndo, " Ask-neighbors2"));
 117                 break;
 118
 119         case DVMRP_NEIGHBORS2:
 120                 ND_PRINT((ndo, " Neighbors2"));
 121                 /*
 122                  * extract version from IGMP group address field
 123                  */
 124                 bp -= 4;
 125                 ND_TCHECK_4(bp);
 126                 major_version = EXTRACT_U_1(bp + 3);
 127                 minor_version = EXTRACT_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((ndo, " Prune"));
 136                 if (print_prune(ndo, bp) < 0)
 137                         goto trunc;
 138                 break;
 139
 140         case DVMRP_GRAFT:
 141                 ND_PRINT((ndo, " Graft"));
 142                 if (print_graft(ndo, bp) < 0)
 143                         goto trunc;
 144                 break;
 145
 146         case DVMRP_GRAFT_ACK:
 147                 ND_PRINT((ndo, " Graft-ACK"));
 148                 if (print_graft_ack(ndo, bp) < 0)
 149                         goto trunc;
 150                 break;
 151
 152         default:
 153                 ND_PRINT((ndo, " [type %d]", type));
 154                 break;
 155         }
 156         return;
 157
 158 trunc:
 159         ND_PRINT((ndo, "[|dvmrp]"));
 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         int metric, done;
 170         u_int i, width;
 171
 172         while (len > 0) {
 173                 if (len < 3) {
 174                         ND_PRINT((ndo, " [|]"));
 175                         return (0);
 176                 }
 177                 ND_TCHECK_3(bp);
 178                 mask = (uint32_t)0xff << 24 | EXTRACT_U_1(bp) << 16 |
 179                         EXTRACT_U_1(bp + 1) << 8 | EXTRACT_U_1(bp + 2);
 180                 width = 1;
 181                 if (EXTRACT_U_1(bp))
 182                         width = 2;
 183                 if (EXTRACT_U_1(bp + 1))
 184                         width = 3;
 185                 if (EXTRACT_U_1(bp + 2))
 186                         width = 4;
 187
 188                 ND_PRINT((ndo, "\n\tMask %s", intoa(htonl(mask))));
 189                 bp += 3;
 190                 len -= 3;
 191                 do {
 192                         if (bp + width + 1 > ep) {
 193                                 ND_PRINT((ndo, " [|]"));
 194                                 return (0);
 195                         }
 196                         if (len < width + 1) {
 197                                 ND_PRINT((ndo, "\n\t  [Truncated Report]"));
 198                                 return (0);
 199                         }
 200                         origin = 0;
 201                         for (i = 0; i < width; ++i) {
 202                                 ND_TCHECK_1(bp);
 203                                 origin = origin << 8 | EXTRACT_U_1(bp);
 204                                 bp++;
 205                         }
 206                         for ( ; i < 4; ++i)
 207                                 origin <<= 8;
 208
 209                         ND_TCHECK_1(bp);
 210                         metric = EXTRACT_U_1(bp);
 211                         bp++;
 212                         done = metric & 0x80;
 213                         metric &= 0x7f;
 214                         ND_PRINT((ndo, "\n\t  %s metric %d", intoa(htonl(origin)),
 215                                 metric));
 216                         len -= width + 1;
 217                 } while (!done);
 218         }
 219         return (0);
 220 trunc:
 221         return (-1);
 222 }
 223
 224 static int
 225 print_probe(netdissect_options *ndo,
 226             const u_char *bp, const u_char *ep,
 227             u_int len)
 228 {
 229         uint32_t genid;
 230
 231         ND_TCHECK_4(bp);
 232         if ((len < 4) || ((bp + 4) > ep)) {
 233                 /* { (ctags) */
 234                 ND_PRINT((ndo, " [|}"));
 235                 return (0);
 236         }
 237         genid = (EXTRACT_U_1(bp) << 24) | (EXTRACT_U_1(bp + 1) << 16) |
 238                  (EXTRACT_U_1(bp + 2) << 8) | EXTRACT_U_1(bp + 3);
 239         bp += 4;
 240         len -= 4;
 241         ND_PRINT((ndo, ndo->ndo_vflag > 1 ? "\n\t" : " "));
 242         ND_PRINT((ndo, "genid %u", genid));
 243         if (ndo->ndo_vflag < 2)
 244                 return (0);
 245
 246         while ((len > 0) && (bp < ep)) {
 247                 ND_TCHECK_4(bp);
 248                 ND_PRINT((ndo, "\n\tneighbor %s", ipaddr_string(ndo, bp)));
 249                 bp += 4; len -= 4;
 250         }
 251         return (0);
 252 trunc:
 253         return (-1);
 254 }
 255
 256 static int
 257 print_neighbors(netdissect_options *ndo,
 258                 const u_char *bp, const u_char *ep,
 259                 u_int len)
 260 {
 261         const u_char *laddr;
 262         u_char metric;
 263         u_char thresh;
 264         int ncount;
 265
 266         while (len > 0 && bp < ep) {
 267                 ND_TCHECK_7(bp);
 268                 laddr = bp;
 269                 bp += 4;
 270                 metric = EXTRACT_U_1(bp);
 271                 bp++;
 272                 thresh = EXTRACT_U_1(bp);
 273                 bp++;
 274                 ncount = EXTRACT_U_1(bp);
 275                 bp++;
 276                 len -= 7;
 277                 while (--ncount >= 0) {
 278                         ND_TCHECK_4(bp);
 279                         ND_PRINT((ndo, " [%s ->", ipaddr_string(ndo, laddr)));
 280                         ND_PRINT((ndo, " %s, (%d/%d)]",
 281                                    ipaddr_string(ndo, bp), metric, thresh));
 282                         bp += 4;
 283                         len -= 4;
 284                 }
 285         }
 286         return (0);
 287 trunc:
 288         return (-1);
 289 }
 290
 291 static int
 292 print_neighbors2(netdissect_options *ndo,
 293                  const u_char *bp, const u_char *ep,
 294                  u_int len, uint8_t major_version,
 295                  uint8_t minor_version)
 296 {
 297         const u_char *laddr;
 298         u_char metric, thresh, flags;
 299         int ncount;
 300
 301         ND_PRINT((ndo, " (v %u.%u):", major_version, minor_version));
 302
 303         while (len > 0 && bp < ep) {
 304                 ND_TCHECK_8(bp);
 305                 laddr = bp;
 306                 bp += 4;
 307                 metric = EXTRACT_U_1(bp);
 308                 bp++;
 309                 thresh = EXTRACT_U_1(bp);
 310                 bp++;
 311                 flags = EXTRACT_U_1(bp);
 312                 bp++;
 313                 ncount = EXTRACT_U_1(bp);
 314                 bp++;
 315                 len -= 8;
 316                 while (--ncount >= 0 && (len >= 4) && (bp + 4) <= ep) {
 317                         ND_PRINT((ndo, " [%s -> ", ipaddr_string(ndo, laddr)));
 318                         ND_PRINT((ndo, "%s (%d/%d", ipaddr_string(ndo, bp),
 319                                      metric, thresh));
 320                         if (flags & DVMRP_NF_TUNNEL)
 321                                 ND_PRINT((ndo, "/tunnel"));
 322                         if (flags & DVMRP_NF_SRCRT)
 323                                 ND_PRINT((ndo, "/srcrt"));
 324                         if (flags & DVMRP_NF_QUERIER)
 325                                 ND_PRINT((ndo, "/querier"));
 326                         if (flags & DVMRP_NF_DISABLED)
 327                                 ND_PRINT((ndo, "/disabled"));
 328                         if (flags & DVMRP_NF_DOWN)
 329                                 ND_PRINT((ndo, "/down"));
 330                         ND_PRINT((ndo, ")]"));
 331                         bp += 4;
 332                         len -= 4;
 333                 }
 334                 if (ncount != -1) {
 335                         ND_PRINT((ndo, " [|]"));
 336                         return (0);
 337                 }
 338         }
 339         return (0);
 340 trunc:
 341         return (-1);
 342 }
 343
 344 static int
 345 print_prune(netdissect_options *ndo,
 346             const u_char *bp)
 347 {
 348         ND_TCHECK_LEN(bp, 12);
 349         ND_PRINT((ndo, " src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4)));
 350         bp += 8;
 351         ND_PRINT((ndo, " timer "));
 352         unsigned_relts_print(ndo, EXTRACT_BE_U_4(bp));
 353         return (0);
 354 trunc:
 355         return (-1);
 356 }
 357
 358 static int
 359 print_graft(netdissect_options *ndo,
 360             const u_char *bp)
 361 {
 362         ND_TCHECK_8(bp);
 363         ND_PRINT((ndo, " src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4)));
 364         return (0);
 365 trunc:
 366         return (-1);
 367 }
 368
 369 static int
 370 print_graft_ack(netdissect_options *ndo,
 371                 const u_char *bp)
 372 {
 373         ND_TCHECK_8(bp);
 374         ND_PRINT((ndo, " src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4)));
 375         return (0);
 376 trunc:
 377         return (-1);
 378 }