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 = EXTRACT_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 = EXTRACT_U_1(bp + 3);
 128                 minor_version = EXTRACT_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("[|dvmrp]");
 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 | EXTRACT_U_1(bp) << 16 |
 180                         EXTRACT_U_1(bp + 1) << 8 | EXTRACT_U_1(bp + 2);
 181                 width = 1;
 182                 if (EXTRACT_U_1(bp))
 183                         width = 2;
 184                 if (EXTRACT_U_1(bp + 1))
 185                         width = 3;
 186                 if (EXTRACT_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 | EXTRACT_U_1(bp);
 205                                 bp++;
 206                         }
 207                         for ( ; i < 4; ++i)
 208                                 origin <<= 8;
 209
 210                         ND_TCHECK_1(bp);
 211                         metric = EXTRACT_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 = (EXTRACT_U_1(bp) << 24) | (EXTRACT_U_1(bp + 1) << 16) |
 239                  (EXTRACT_U_1(bp + 2) << 8) | EXTRACT_U_1(bp + 3);
 240         bp += 4;
 241         len -= 4;
 242         ND_PRINT(ndo->ndo_vflag > 1 ? "\n\t" : " ");
 243         ND_PRINT("genid %u", genid);
 244         if (ndo->ndo_vflag < 2)
 245                 return (0);
 246
 247         while ((len > 0) && (bp < ep)) {
 248                 ND_TCHECK_4(bp);
 249                 ND_PRINT("\n\tneighbor %s", ipaddr_string(ndo, bp));
 250                 bp += 4; len -= 4;
 251         }
 252         return (0);
 253 trunc:
 254         return (-1);
 255 }
 256
 257 static int
 258 print_neighbors(netdissect_options *ndo,
 259                 const u_char *bp, const u_char *ep,
 260                 u_int len)
 261 {
 262         const u_char *laddr;
 263         u_char metric;
 264         u_char thresh;
 265         int ncount;
 266
 267         while (len > 0 && bp < ep) {
 268                 ND_TCHECK_7(bp);
 269                 laddr = bp;
 270                 bp += 4;
 271                 metric = EXTRACT_U_1(bp);
 272                 bp++;
 273                 thresh = EXTRACT_U_1(bp);
 274                 bp++;
 275                 ncount = EXTRACT_U_1(bp);
 276                 bp++;
 277                 len -= 7;
 278                 while (--ncount >= 0) {
 279                         ND_TCHECK_4(bp);
 280                         ND_PRINT(" [%s ->", ipaddr_string(ndo, laddr));
 281                         ND_PRINT(" %s, (%u/%u)]",
 282                                    ipaddr_string(ndo, bp), metric, thresh);
 283                         bp += 4;
 284                         len -= 4;
 285                 }
 286         }
 287         return (0);
 288 trunc:
 289         return (-1);
 290 }
 291
 292 static int
 293 print_neighbors2(netdissect_options *ndo,
 294                  const u_char *bp, const u_char *ep,
 295                  u_int len, uint8_t major_version,
 296                  uint8_t minor_version)
 297 {
 298         const u_char *laddr;
 299         u_char metric, thresh, flags;
 300         int ncount;
 301
 302         ND_PRINT(" (v %u.%u):", major_version, minor_version);
 303
 304         while (len > 0 && bp < ep) {
 305                 ND_TCHECK_8(bp);
 306                 laddr = bp;
 307                 bp += 4;
 308                 metric = EXTRACT_U_1(bp);
 309                 bp++;
 310                 thresh = EXTRACT_U_1(bp);
 311                 bp++;
 312                 flags = EXTRACT_U_1(bp);
 313                 bp++;
 314                 ncount = EXTRACT_U_1(bp);
 315                 bp++;
 316                 len -= 8;
 317                 while (--ncount >= 0 && (len >= 4) && (bp + 4) <= ep) {
 318                         ND_PRINT(" [%s -> ", ipaddr_string(ndo, laddr));
 319                         ND_PRINT("%s (%u/%u", ipaddr_string(ndo, bp),
 320                                      metric, thresh);
 321                         if (flags & DVMRP_NF_TUNNEL)
 322                                 ND_PRINT("/tunnel");
 323                         if (flags & DVMRP_NF_SRCRT)
 324                                 ND_PRINT("/srcrt");
 325                         if (flags & DVMRP_NF_QUERIER)
 326                                 ND_PRINT("/querier");
 327                         if (flags & DVMRP_NF_DISABLED)
 328                                 ND_PRINT("/disabled");
 329                         if (flags & DVMRP_NF_DOWN)
 330                                 ND_PRINT("/down");
 331                         ND_PRINT(")]");
 332                         bp += 4;
 333                         len -= 4;
 334                 }
 335                 if (ncount != -1) {
 336                         ND_PRINT(" [|]");
 337                         return (0);
 338                 }
 339         }
 340         return (0);
 341 trunc:
 342         return (-1);
 343 }
 344
 345 static int
 346 print_prune(netdissect_options *ndo,
 347             const u_char *bp)
 348 {
 349         ND_TCHECK_LEN(bp, 12);
 350         ND_PRINT(" src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4));
 351         bp += 8;
 352         ND_PRINT(" timer ");
 353         unsigned_relts_print(ndo, EXTRACT_BE_U_4(bp));
 354         return (0);
 355 trunc:
 356         return (-1);
 357 }
 358
 359 static int
 360 print_graft(netdissect_options *ndo,
 361             const u_char *bp)
 362 {
 363         ND_TCHECK_8(bp);
 364         ND_PRINT(" src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4));
 365         return (0);
 366 trunc:
 367         return (-1);
 368 }
 369
 370 static int
 371 print_graft_ack(netdissect_options *ndo,
 372                 const u_char *bp)
 373 {
 374         ND_TCHECK_8(bp);
 375         ND_PRINT(" src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4));
 376         return (0);
 377 trunc:
 378         return (-1);
 379 }