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             register const u_char *bp, register u_int len)
  71 {
  72         register const u_char *ep;
  73         register 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              register const u_char *bp, register const u_char *ep,
 166              register u_int len)
 167 {
 168         register uint32_t mask, origin;
 169         register int metric, done;
 170         register 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 | bp[0] << 16 | bp[1] << 8 | bp[2];
 179                 width = 1;
 180                 if (bp[0])
 181                         width = 2;
 182                 if (bp[1])
 183                         width = 3;
 184                 if (bp[2])
 185                         width = 4;
 186
 187                 ND_PRINT((ndo, "\n\tMask %s", intoa(htonl(mask))));
 188                 bp += 3;
 189                 len -= 3;
 190                 do {
 191                         if (bp + width + 1 > ep) {
 192                                 ND_PRINT((ndo, " [|]"));
 193                                 return (0);
 194                         }
 195                         if (len < width + 1) {
 196                                 ND_PRINT((ndo, "\n\t  [Truncated Report]"));
 197                                 return (0);
 198                         }
 199                         origin = 0;
 200                         for (i = 0; i < width; ++i) {
 201                                 ND_TCHECK_1(bp);
 202                                 origin = origin << 8 | EXTRACT_U_1(bp);
 203                                 bp++;
 204                         }
 205                         for ( ; i < 4; ++i)
 206                                 origin <<= 8;
 207
 208                         ND_TCHECK_1(bp);
 209                         metric = EXTRACT_U_1(bp);
 210                         bp++;
 211                         done = metric & 0x80;
 212                         metric &= 0x7f;
 213                         ND_PRINT((ndo, "\n\t  %s metric %d", intoa(htonl(origin)),
 214                                 metric));
 215                         len -= width + 1;
 216                 } while (!done);
 217         }
 218         return (0);
 219 trunc:
 220         return (-1);
 221 }
 222
 223 static int
 224 print_probe(netdissect_options *ndo,
 225             register const u_char *bp, register const u_char *ep,
 226             register u_int len)
 227 {
 228         register uint32_t genid;
 229
 230         ND_TCHECK_4(bp);
 231         if ((len < 4) || ((bp + 4) > ep)) {
 232                 /* { (ctags) */
 233                 ND_PRINT((ndo, " [|}"));
 234                 return (0);
 235         }
 236         genid = (bp[0] << 24) | (bp[1] << 16) | (bp[2] << 8) | bp[3];
 237         bp += 4;
 238         len -= 4;
 239         ND_PRINT((ndo, ndo->ndo_vflag > 1 ? "\n\t" : " "));
 240         ND_PRINT((ndo, "genid %u", genid));
 241         if (ndo->ndo_vflag < 2)
 242                 return (0);
 243
 244         while ((len > 0) && (bp < ep)) {
 245                 ND_TCHECK_4(bp);
 246                 ND_PRINT((ndo, "\n\tneighbor %s", ipaddr_string(ndo, bp)));
 247                 bp += 4; len -= 4;
 248         }
 249         return (0);
 250 trunc:
 251         return (-1);
 252 }
 253
 254 static int
 255 print_neighbors(netdissect_options *ndo,
 256                 register const u_char *bp, register const u_char *ep,
 257                 register u_int len)
 258 {
 259         const u_char *laddr;
 260         register u_char metric;
 261         register u_char thresh;
 262         register int ncount;
 263
 264         while (len > 0 && bp < ep) {
 265                 ND_TCHECK_7(bp);
 266                 laddr = bp;
 267                 bp += 4;
 268                 metric = EXTRACT_U_1(bp);
 269                 bp++;
 270                 thresh = EXTRACT_U_1(bp);
 271                 bp++;
 272                 ncount = EXTRACT_U_1(bp);
 273                 bp++;
 274                 len -= 7;
 275                 while (--ncount >= 0) {
 276                         ND_TCHECK_4(bp);
 277                         ND_PRINT((ndo, " [%s ->", ipaddr_string(ndo, laddr)));
 278                         ND_PRINT((ndo, " %s, (%d/%d)]",
 279                                    ipaddr_string(ndo, bp), metric, thresh));
 280                         bp += 4;
 281                         len -= 4;
 282                 }
 283         }
 284         return (0);
 285 trunc:
 286         return (-1);
 287 }
 288
 289 static int
 290 print_neighbors2(netdissect_options *ndo,
 291                  register const u_char *bp, register const u_char *ep,
 292                  register u_int len, uint8_t major_version,
 293                  uint8_t minor_version)
 294 {
 295         const u_char *laddr;
 296         register u_char metric, thresh, flags;
 297         register int ncount;
 298
 299         ND_PRINT((ndo, " (v %u.%u):", major_version, minor_version));
 300
 301         while (len > 0 && bp < ep) {
 302                 ND_TCHECK_8(bp);
 303                 laddr = bp;
 304                 bp += 4;
 305                 metric = EXTRACT_U_1(bp);
 306                 bp++;
 307                 thresh = EXTRACT_U_1(bp);
 308                 bp++;
 309                 flags = EXTRACT_U_1(bp);
 310                 bp++;
 311                 ncount = EXTRACT_U_1(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_U_4(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_TCHECK_8(bp);
 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_TCHECK_8(bp);
 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 }