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  * 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
  49 /*
  50  * 'flags' byte values in DVMRP_NEIGHBORS2 reply.
  51  */
  52 #define DVMRP_NF_TUNNEL         0x01    /* neighbors reached via tunnel */
  53 #define DVMRP_NF_SRCRT          0x02    /* tunnel uses IP source routing */
  54 #define DVMRP_NF_DOWN           0x10    /* kernel state of interface */
  55 #define DVMRP_NF_DISABLED       0x20    /* administratively disabled */
  56 #define DVMRP_NF_QUERIER        0x40    /* I am the subnet's querier */
  57
  58 static int print_probe(netdissect_options *, const u_char *, const u_char *, u_int);
  59 static int print_report(netdissect_options *, const u_char *, const u_char *, u_int);
  60 static int print_neighbors(netdissect_options *, const u_char *, const u_char *, u_int);
  61 static int print_neighbors2(netdissect_options *, const u_char *, const u_char *, u_int);
  62 static int print_prune(netdissect_options *, const u_char *);
  63 static int print_graft(netdissect_options *, const u_char *);
  64 static int print_graft_ack(netdissect_options *, const u_char *);
  65
  66 static uint32_t target_level;
  67
  68 void
  69 dvmrp_print(netdissect_options *ndo,
  70             register const u_char *bp, register u_int len)
  71 {
  72         register const u_char *ep;
  73         register u_char type;
  74
  75         ep = (const u_char *)ndo->ndo_snapend;
  76         if (bp >= ep)
  77                 return;
  78
  79         ND_TCHECK(bp[1]);
  80         type = bp[1];
  81
  82         /* Skip IGMP header */
  83         bp += 8;
  84         len -= 8;
  85
  86         switch (type) {
  87
  88         case DVMRP_PROBE:
  89                 ND_PRINT((ndo, " Probe"));
  90                 if (ndo->ndo_vflag) {
  91                         if (print_probe(ndo, bp, ep, len) < 0)
  92                                 goto trunc;
  93                 }
  94                 break;
  95
  96         case DVMRP_REPORT:
  97                 ND_PRINT((ndo, " Report"));
  98                 if (ndo->ndo_vflag > 1) {
  99                         if (print_report(ndo, bp, ep, len) < 0)
 100                                 goto trunc;
 101                 }
 102                 break;
 103
 104         case DVMRP_ASK_NEIGHBORS:
 105                 ND_PRINT((ndo, " Ask-neighbors(old)"));
 106                 break;
 107
 108         case DVMRP_NEIGHBORS:
 109                 ND_PRINT((ndo, " Neighbors(old)"));
 110                 if (print_neighbors(ndo, bp, ep, len) < 0)
 111                         goto trunc;
 112                 break;
 113
 114         case DVMRP_ASK_NEIGHBORS2:
 115                 ND_PRINT((ndo, " Ask-neighbors2"));
 116                 break;
 117
 118         case DVMRP_NEIGHBORS2:
 119                 ND_PRINT((ndo, " Neighbors2"));
 120                 /*
 121                  * extract version and capabilities from IGMP group
 122                  * address field
 123                  */
 124                 bp -= 4;
 125                 ND_TCHECK2(bp[0], 4);
 126                 target_level = (bp[0] << 24) | (bp[1] << 16) |
 127                     (bp[2] << 8) | bp[3];
 128                 bp += 4;
 129                 if (print_neighbors2(ndo, bp, ep, len) < 0)
 130                         goto trunc;
 131                 break;
 132
 133         case DVMRP_PRUNE:
 134                 ND_PRINT((ndo, " Prune"));
 135                 if (print_prune(ndo, bp) < 0)
 136                         goto trunc;
 137                 break;
 138
 139         case DVMRP_GRAFT:
 140                 ND_PRINT((ndo, " Graft"));
 141                 if (print_graft(ndo, bp) < 0)
 142                         goto trunc;
 143                 break;
 144
 145         case DVMRP_GRAFT_ACK:
 146                 ND_PRINT((ndo, " Graft-ACK"));
 147                 if (print_graft_ack(ndo, bp) < 0)
 148                         goto trunc;
 149                 break;
 150
 151         default:
 152                 ND_PRINT((ndo, " [type %d]", type));
 153                 break;
 154         }
 155         return;
 156
 157 trunc:
 158         ND_PRINT((ndo, "[|dvmrp]"));
 159         return;
 160 }
 161
 162 static int
 163 print_report(netdissect_options *ndo,
 164              register const u_char *bp, register const u_char *ep,
 165              register u_int len)
 166 {
 167         register uint32_t mask, origin;
 168         register int metric, done;
 169         register u_int i, width;
 170
 171         while (len > 0) {
 172                 if (len < 3) {
 173                         ND_PRINT((ndo, " [|]"));
 174                         return (0);
 175                 }
 176                 ND_TCHECK2(bp[0], 3);
 177                 mask = (uint32_t)0xff << 24 | bp[0] << 16 | bp[1] << 8 | bp[2];
 178                 width = 1;
 179                 if (bp[0])
 180                         width = 2;
 181                 if (bp[1])
 182                         width = 3;
 183                 if (bp[2])
 184                         width = 4;
 185
 186                 ND_PRINT((ndo, "\n\tMask %s", intoa(htonl(mask))));
 187                 bp += 3;
 188                 len -= 3;
 189                 do {
 190                         if (bp + width + 1 > ep) {
 191                                 ND_PRINT((ndo, " [|]"));
 192                                 return (0);
 193                         }
 194                         if (len < width + 1) {
 195                                 ND_PRINT((ndo, "\n\t  [Truncated Report]"));
 196                                 return (0);
 197                         }
 198                         origin = 0;
 199                         for (i = 0; i < width; ++i) {
 200                                 ND_TCHECK_8BITS(bp);
 201                                 origin = origin << 8 | EXTRACT_8BITS(bp);
 202                                 bp++;
 203                         }
 204                         for ( ; i < 4; ++i)
 205                                 origin <<= 8;
 206
 207                         ND_TCHECK_8BITS(bp);
 208                         metric = EXTRACT_8BITS(bp);
 209                         bp++;
 210                         done = metric & 0x80;
 211                         metric &= 0x7f;
 212                         ND_PRINT((ndo, "\n\t  %s metric %d", 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             register const u_char *bp, register const u_char *ep,
 225             register u_int len)
 226 {
 227         register uint32_t genid;
 228
 229         ND_TCHECK2(bp[0], 4);
 230         if ((len < 4) || ((bp + 4) > ep)) {
 231                 /* { (ctags) */
 232                 ND_PRINT((ndo, " [|}"));
 233                 return (0);
 234         }
 235         genid = (bp[0] << 24) | (bp[1] << 16) | (bp[2] << 8) | bp[3];
 236         bp += 4;
 237         len -= 4;
 238         ND_PRINT((ndo, ndo->ndo_vflag > 1 ? "\n\t" : " "));
 239         ND_PRINT((ndo, "genid %u", genid));
 240         if (ndo->ndo_vflag < 2)
 241                 return (0);
 242
 243         while ((len > 0) && (bp < ep)) {
 244                 ND_TCHECK2(bp[0], 4);
 245                 ND_PRINT((ndo, "\n\tneighbor %s", ipaddr_string(ndo, 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                 register const u_char *bp, register const u_char *ep,
 256                 register u_int len)
 257 {
 258         const u_char *laddr;
 259         register u_char metric;
 260         register u_char thresh;
 261         register int ncount;
 262
 263         while (len > 0 && bp < ep) {
 264                 ND_TCHECK2(bp[0], 7);
 265                 laddr = bp;
 266                 bp += 4;
 267                 metric = EXTRACT_8BITS(bp);
 268                 bp++;
 269                 thresh = EXTRACT_8BITS(bp);
 270                 bp++;
 271                 ncount = EXTRACT_8BITS(bp);
 272                 bp++;
 273                 len -= 7;
 274                 while (--ncount >= 0) {
 275                         ND_TCHECK2(bp[0], 4);
 276                         ND_PRINT((ndo, " [%s ->", ipaddr_string(ndo, laddr)));
 277                         ND_PRINT((ndo, " %s, (%d/%d)]",
 278                                    ipaddr_string(ndo, 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                  register const u_char *bp, register const u_char *ep,
 291                  register u_int len)
 292 {
 293         const u_char *laddr;
 294         register u_char metric, thresh, flags;
 295         register int ncount;
 296
 297         ND_PRINT((ndo, " (v %d.%d):",
 298                (int)target_level & 0xff,
 299                (int)(target_level >> 8) & 0xff));
 300
 301         while (len > 0 && bp < ep) {
 302                 ND_TCHECK2(bp[0], 8);
 303                 laddr = bp;
 304                 bp += 4;
 305                 metric = EXTRACT_8BITS(bp);
 306                 bp++;
 307                 thresh = EXTRACT_8BITS(bp);
 308                 bp++;
 309                 flags = EXTRACT_8BITS(bp);
 310                 bp++;
 311                 ncount = EXTRACT_8BITS(bp);
 312                 bp++;
 313                 len -= 8;
 314                 while (--ncount >= 0 && (len >= 4) && (bp + 4) <= ep) {
 315                         ND_PRINT((ndo, " [%s -> ", ipaddr_string(ndo, laddr)));
 316                         ND_PRINT((ndo, "%s (%d/%d", ipaddr_string(ndo, bp),
 317                                      metric, thresh));
 318                         if (flags & DVMRP_NF_TUNNEL)
 319                                 ND_PRINT((ndo, "/tunnel"));
 320                         if (flags & DVMRP_NF_SRCRT)
 321                                 ND_PRINT((ndo, "/srcrt"));
 322                         if (flags & DVMRP_NF_QUERIER)
 323                                 ND_PRINT((ndo, "/querier"));
 324                         if (flags & DVMRP_NF_DISABLED)
 325                                 ND_PRINT((ndo, "/disabled"));
 326                         if (flags & DVMRP_NF_DOWN)
 327                                 ND_PRINT((ndo, "/down"));
 328                         ND_PRINT((ndo, ")]"));
 329                         bp += 4;
 330                         len -= 4;
 331                 }
 332                 if (ncount != -1) {
 333                         ND_PRINT((ndo, " [|]"));
 334                         return (0);
 335                 }
 336         }
 337         return (0);
 338 trunc:
 339         return (-1);
 340 }
 341
 342 static int
 343 print_prune(netdissect_options *ndo,
 344             register const u_char *bp)
 345 {
 346         ND_TCHECK2(bp[0], 12);
 347         ND_PRINT((ndo, " src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4)));
 348         bp += 8;
 349         ND_PRINT((ndo, " timer "));
 350         unsigned_relts_print(ndo, EXTRACT_BE_32BITS(bp));
 351         return (0);
 352 trunc:
 353         return (-1);
 354 }
 355
 356 static int
 357 print_graft(netdissect_options *ndo,
 358             register const u_char *bp)
 359 {
 360         ND_TCHECK2(bp[0], 8);
 361         ND_PRINT((ndo, " src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4)));
 362         return (0);
 363 trunc:
 364         return (-1);
 365 }
 366
 367 static int
 368 print_graft_ack(netdissect_options *ndo,
 369                 register const u_char *bp)
 370 {
 371         ND_TCHECK2(bp[0], 8);
 372         ND_PRINT((ndo, " src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4)));
 373         return (0);
 374 trunc:
 375         return (-1);
 376 }