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         ND_TCHECK_1(bp + 1);
  82         type = GET_U_1(bp + 1);
  83
  84         /* Skip IGMP header */
  85         bp += 8;
  86         len -= 8;
  87
  88         switch (type) {
  89
  90         case DVMRP_PROBE:
  91                 ND_PRINT(" Probe");
  92                 if (ndo->ndo_vflag) {
  93                         if (print_probe(ndo, bp, ep, len) < 0)
  94                                 goto trunc;
  95                 }
  96                 break;
  97
  98         case DVMRP_REPORT:
  99                 ND_PRINT(" Report");
 100                 if (ndo->ndo_vflag > 1) {
 101                         if (print_report(ndo, bp, ep, len) < 0)
 102                                 goto trunc;
 103                 }
 104                 break;
 105
 106         case DVMRP_ASK_NEIGHBORS:
 107                 ND_PRINT(" Ask-neighbors(old)");
 108                 break;
 109
 110         case DVMRP_NEIGHBORS:
 111                 ND_PRINT(" Neighbors(old)");
 112                 if (print_neighbors(ndo, bp, ep, len) < 0)
 113                         goto trunc;
 114                 break;
 115
 116         case DVMRP_ASK_NEIGHBORS2:
 117                 ND_PRINT(" Ask-neighbors2");
 118                 break;
 119
 120         case DVMRP_NEIGHBORS2:
 121                 ND_PRINT(" Neighbors2");
 122                 /*
 123                  * extract version from IGMP group address field
 124                  */
 125                 bp -= 4;
 126                 ND_TCHECK_4(bp);
 127                 major_version = GET_U_1(bp + 3);
 128                 minor_version = GET_U_1(bp + 2);
 129                 bp += 4;
 130                 if (print_neighbors2(ndo, bp, ep, len, major_version,
 131                     minor_version) < 0)
 132                         goto trunc;
 133                 break;
 134
 135         case DVMRP_PRUNE:
 136                 ND_PRINT(" Prune");
 137                 if (print_prune(ndo, bp) < 0)
 138                         goto trunc;
 139                 break;
 140
 141         case DVMRP_GRAFT:
 142                 ND_PRINT(" Graft");
 143                 if (print_graft(ndo, bp) < 0)
 144                         goto trunc;
 145                 break;
 146
 147         case DVMRP_GRAFT_ACK:
 148                 ND_PRINT(" Graft-ACK");
 149                 if (print_graft_ack(ndo, bp) < 0)
 150                         goto trunc;
 151                 break;
 152
 153         default:
 154                 ND_PRINT(" [type %u]", type);
 155                 break;
 156         }
 157         return;
 158
 159 trunc:
 160         nd_print_trunc(ndo);
 161         return;
 162 }
 163
 164 static int
 165 print_report(netdissect_options *ndo,
 166              const u_char *bp, const u_char *ep,
 167              u_int len)
 168 {
 169         uint32_t mask, origin;
 170         u_int metric, done;
 171         u_int i, width;
 172
 173         while (len > 0) {
 174                 if (len < 3) {
 175                         ND_PRINT(" [|]");
 176                         return (0);
 177                 }
 178                 ND_TCHECK_3(bp);
 179                 mask = (uint32_t)0xff << 24 | GET_U_1(bp) << 16 |
 180                         GET_U_1(bp + 1) << 8 | GET_U_1(bp + 2);
 181                 width = 1;
 182                 if (GET_U_1(bp))
 183                         width = 2;
 184                 if (GET_U_1(bp + 1))
 185                         width = 3;
 186                 if (GET_U_1(bp + 2))
 187                         width = 4;
 188
 189                 ND_PRINT("\n\tMask %s", intoa(htonl(mask)));
 190                 bp += 3;
 191                 len -= 3;
 192                 do {
 193                         if (bp + width + 1 > ep) {
 194                                 ND_PRINT(" [|]");
 195                                 return (0);
 196                         }
 197                         if (len < width + 1) {
 198                                 ND_PRINT("\n\t  [Truncated Report]");
 199                                 return (0);
 200                         }
 201                         origin = 0;
 202                         for (i = 0; i < width; ++i) {
 203                                 ND_TCHECK_1(bp);
 204                                 origin = origin << 8 | GET_U_1(bp);
 205                                 bp++;
 206                         }
 207                         for ( ; i < 4; ++i)
 208                                 origin <<= 8;
 209
 210                         ND_TCHECK_1(bp);
 211                         metric = GET_U_1(bp);
 212                         bp++;
 213                         done = metric & 0x80;
 214                         metric &= 0x7f;
 215                         ND_PRINT("\n\t  %s metric %u", intoa(htonl(origin)),
 216                                 metric);
 217                         len -= width + 1;
 218                 } while (!done);
 219         }
 220         return (0);
 221 trunc:
 222         return (-1);
 223 }
 224
 225 static int
 226 print_probe(netdissect_options *ndo,
 227             const u_char *bp, const u_char *ep,
 228             u_int len)
 229 {
 230         uint32_t genid;
 231
 232         ND_TCHECK_4(bp);
 233         if ((len < 4) || ((bp + 4) > ep)) {
 234                 /* { (ctags) */
 235                 ND_PRINT(" [|}");
 236                 return (0);
 237         }
 238         genid = GET_BE_U_4(bp);
 239         bp += 4;
 240         len -= 4;
 241         ND_PRINT(ndo->ndo_vflag > 1 ? "\n\t" : " ");
 242         ND_PRINT("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("\n\tneighbor %s", GET_IPADDR_STRING(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 = GET_U_1(bp);
 271                 bp++;
 272                 thresh = GET_U_1(bp);
 273                 bp++;
 274                 ncount = GET_U_1(bp);
 275                 bp++;
 276                 len -= 7;
 277                 while (--ncount >= 0) {
 278                         ND_TCHECK_4(bp);
 279                         ND_PRINT(" [%s ->", GET_IPADDR_STRING(laddr));
 280                         ND_PRINT(" %s, (%u/%u)]",
 281                                    GET_IPADDR_STRING(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(" (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 = GET_U_1(bp);
 308                 bp++;
 309                 thresh = GET_U_1(bp);
 310                 bp++;
 311                 flags = GET_U_1(bp);
 312                 bp++;
 313                 ncount = GET_U_1(bp);
 314                 bp++;
 315                 len -= 8;
 316                 while (--ncount >= 0 && (len >= 4) && (bp + 4) <= ep) {
 317                         ND_PRINT(" [%s -> ", GET_IPADDR_STRING(laddr));
 318                         ND_PRINT("%s (%u/%u", GET_IPADDR_STRING(bp),
 319                                      metric, thresh);
 320                         if (flags & DVMRP_NF_TUNNEL)
 321                                 ND_PRINT("/tunnel");
 322                         if (flags & DVMRP_NF_SRCRT)
 323                                 ND_PRINT("/srcrt");
 324                         if (flags & DVMRP_NF_QUERIER)
 325                                 ND_PRINT("/querier");
 326                         if (flags & DVMRP_NF_DISABLED)
 327                                 ND_PRINT("/disabled");
 328                         if (flags & DVMRP_NF_DOWN)
 329                                 ND_PRINT("/down");
 330                         ND_PRINT(")]");
 331                         bp += 4;
 332                         len -= 4;
 333                 }
 334                 if (ncount != -1) {
 335                         ND_PRINT(" [|]");
 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(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(bp + 4));
 350         bp += 8;
 351         ND_PRINT(" timer ");
 352         unsigned_relts_print(ndo, GET_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(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(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(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(bp + 4));
 375         return (0);
 376 trunc:
 377         return (-1);
 378 }