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         type = GET_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(" 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(" 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(" Ask-neighbors(old)");
 107                 break;
 108
 109         case DVMRP_NEIGHBORS:
 110                 ND_PRINT(" 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(" Ask-neighbors2");
 117                 break;
 118
 119         case DVMRP_NEIGHBORS2:
 120                 ND_PRINT(" Neighbors2");
 121                 /*
 122                  * extract version from IGMP group address field
 123                  */
 124                 bp -= 4;
 125                 major_version = GET_U_1(bp + 3);
 126                 minor_version = GET_U_1(bp + 2);
 127                 bp += 4;
 128                 if (print_neighbors2(ndo, bp, ep, len, major_version,
 129                     minor_version) < 0)
 130                         goto trunc;
 131                 break;
 132
 133         case DVMRP_PRUNE:
 134                 ND_PRINT(" Prune");
 135                 if (print_prune(ndo, bp) < 0)
 136                         goto trunc;
 137                 break;
 138
 139         case DVMRP_GRAFT:
 140                 ND_PRINT(" Graft");
 141                 if (print_graft(ndo, bp) < 0)
 142                         goto trunc;
 143                 break;
 144
 145         case DVMRP_GRAFT_ACK:
 146                 ND_PRINT(" Graft-ACK");
 147                 if (print_graft_ack(ndo, bp) < 0)
 148                         goto trunc;
 149                 break;
 150
 151         default:
 152                 ND_PRINT(" [type %u]", type);
 153                 break;
 154         }
 155         return;
 156
 157 trunc:
 158         nd_print_trunc(ndo);
 159 }
 160
 161 static int
 162 print_report(netdissect_options *ndo,
 163              const u_char *bp, const u_char *ep,
 164              u_int len)
 165 {
 166         uint32_t mask, origin;
 167         u_int metric, done;
 168         u_int i, width;
 169
 170         while (len > 0) {
 171                 if (len < 3) {
 172                         ND_PRINT(" [|]");
 173                         return (0);
 174                 }
 175                 mask = (uint32_t)0xff << 24 | GET_U_1(bp) << 16 |
 176                         GET_U_1(bp + 1) << 8 | GET_U_1(bp + 2);
 177                 width = 1;
 178                 if (GET_U_1(bp))
 179                         width = 2;
 180                 if (GET_U_1(bp + 1))
 181                         width = 3;
 182                 if (GET_U_1(bp + 2))
 183                         width = 4;
 184
 185                 ND_PRINT("\n\tMask %s", intoa(htonl(mask)));
 186                 bp += 3;
 187                 len -= 3;
 188                 do {
 189                         if (bp + width + 1 > ep) {
 190                                 ND_PRINT(" [|]");
 191                                 return (0);
 192                         }
 193                         if (len < width + 1) {
 194                                 ND_PRINT("\n\t  [Truncated Report]");
 195                                 return (0);
 196                         }
 197                         origin = 0;
 198                         for (i = 0; i < width; ++i) {
 199                                 origin = origin << 8 | GET_U_1(bp);
 200                                 bp++;
 201                         }
 202                         for ( ; i < 4; ++i)
 203                                 origin <<= 8;
 204
 205                         metric = GET_U_1(bp);
 206                         bp++;
 207                         done = metric & 0x80;
 208                         metric &= 0x7f;
 209                         ND_PRINT("\n\t  %s metric %u", intoa(htonl(origin)),
 210                                 metric);
 211                         len -= width + 1;
 212                 } while (!done);
 213         }
 214         return (0);
 215 }
 216
 217 static int
 218 print_probe(netdissect_options *ndo,
 219             const u_char *bp, const u_char *ep,
 220             u_int len)
 221 {
 222         uint32_t genid;
 223
 224         ND_TCHECK_4(bp);
 225         if ((len < 4) || ((bp + 4) > ep)) {
 226                 ND_PRINT(" [|}");
 227                 return (0);
 228         }
 229         genid = GET_BE_U_4(bp);
 230         bp += 4;
 231         len -= 4;
 232         ND_PRINT(ndo->ndo_vflag > 1 ? "\n\t" : " ");
 233         ND_PRINT("genid %u", genid);
 234         if (ndo->ndo_vflag < 2)
 235                 return (0);
 236
 237         while ((len > 0) && (bp < ep)) {
 238                 ND_PRINT("\n\tneighbor %s", GET_IPADDR_STRING(bp));
 239                 bp += 4; len -= 4;
 240         }
 241         return (0);
 242 trunc:
 243         return (-1);
 244 }
 245
 246 static int
 247 print_neighbors(netdissect_options *ndo,
 248                 const u_char *bp, const u_char *ep,
 249                 u_int len)
 250 {
 251         const u_char *laddr;
 252         u_char metric;
 253         u_char thresh;
 254         int ncount;
 255
 256         while (len > 0 && bp < ep) {
 257                 ND_TCHECK_7(bp);
 258                 laddr = bp;
 259                 bp += 4;
 260                 metric = GET_U_1(bp);
 261                 bp++;
 262                 thresh = GET_U_1(bp);
 263                 bp++;
 264                 ncount = GET_U_1(bp);
 265                 bp++;
 266                 len -= 7;
 267                 while (--ncount >= 0) {
 268                         ND_PRINT(" [%s ->", GET_IPADDR_STRING(laddr));
 269                         ND_PRINT(" %s, (%u/%u)]",
 270                                    GET_IPADDR_STRING(bp), metric, thresh);
 271                         bp += 4;
 272                         len -= 4;
 273                 }
 274         }
 275         return (0);
 276 trunc:
 277         return (-1);
 278 }
 279
 280 static int
 281 print_neighbors2(netdissect_options *ndo,
 282                  const u_char *bp, const u_char *ep,
 283                  u_int len, uint8_t major_version,
 284                  uint8_t minor_version)
 285 {
 286         const u_char *laddr;
 287         u_char metric, thresh, flags;
 288         int ncount;
 289
 290         ND_PRINT(" (v %u.%u):", major_version, minor_version);
 291
 292         while (len > 0 && bp < ep) {
 293                 ND_TCHECK_8(bp);
 294                 laddr = bp;
 295                 bp += 4;
 296                 metric = GET_U_1(bp);
 297                 bp++;
 298                 thresh = GET_U_1(bp);
 299                 bp++;
 300                 flags = GET_U_1(bp);
 301                 bp++;
 302                 ncount = GET_U_1(bp);
 303                 bp++;
 304                 len -= 8;
 305                 while (--ncount >= 0 && (len >= 4) && (bp + 4) <= ep) {
 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(" [|]");
 325                         return (0);
 326                 }
 327         }
 328         return (0);
 329 trunc:
 330         return (-1);
 331 }
 332
 333 static int
 334 print_prune(netdissect_options *ndo,
 335             const u_char *bp)
 336 {
 337         ND_PRINT(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(bp + 4));
 338         bp += 8;
 339         ND_PRINT(" timer ");
 340         unsigned_relts_print(ndo, GET_BE_U_4(bp));
 341         return (0);
 342 }
 343
 344 static int
 345 print_graft(netdissect_options *ndo,
 346             const u_char *bp)
 347 {
 348         ND_PRINT(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(bp + 4));
 349         return (0);
 350 }
 351
 352 static int
 353 print_graft_ack(netdissect_options *ndo,
 354                 const u_char *bp)
 355 {
 356         ND_PRINT(" src %s grp %s", GET_IPADDR_STRING(bp), GET_IPADDR_STRING(bp + 4));
 357         return (0);
 358 }