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(*bp);
 201                                 origin = origin << 8 | *bp++;
 202                         }
 203                         for ( ; i < 4; ++i)
 204                                 origin <<= 8;
 205
 206                         ND_TCHECK(*bp);
 207                         metric = *bp++;
 208                         done = metric & 0x80;
 209                         metric &= 0x7f;
 210                         ND_PRINT((ndo, "\n\t  %s metric %d", intoa(htonl(origin)),
 211                                 metric));
 212                         len -= width + 1;
 213                 } while (!done);
 214         }
 215         return (0);
 216 trunc:
 217         return (-1);
 218 }
 219
 220 static int
 221 print_probe(netdissect_options *ndo,
 222             register const u_char *bp, register const u_char *ep,
 223             register u_int len)
 224 {
 225         register uint32_t genid;
 226
 227         ND_TCHECK2(bp[0], 4);
 228         if ((len < 4) || ((bp + 4) > ep)) {
 229                 /* { (ctags) */
 230                 ND_PRINT((ndo, " [|}"));
 231                 return (0);
 232         }
 233         genid = (bp[0] << 24) | (bp[1] << 16) | (bp[2] << 8) | bp[3];
 234         bp += 4;
 235         len -= 4;
 236         ND_PRINT((ndo, ndo->ndo_vflag > 1 ? "\n\t" : " "));
 237         ND_PRINT((ndo, "genid %u", genid));
 238         if (ndo->ndo_vflag < 2)
 239                 return (0);
 240
 241         while ((len > 0) && (bp < ep)) {
 242                 ND_TCHECK2(bp[0], 4);
 243                 ND_PRINT((ndo, "\n\tneighbor %s", ipaddr_string(ndo, bp)));
 244                 bp += 4; len -= 4;
 245         }
 246         return (0);
 247 trunc:
 248         return (-1);
 249 }
 250
 251 static int
 252 print_neighbors(netdissect_options *ndo,
 253                 register const u_char *bp, register const u_char *ep,
 254                 register u_int len)
 255 {
 256         const u_char *laddr;
 257         register u_char metric;
 258         register u_char thresh;
 259         register int ncount;
 260
 261         while (len > 0 && bp < ep) {
 262                 ND_TCHECK2(bp[0], 7);
 263                 laddr = bp;
 264                 bp += 4;
 265                 metric = *bp++;
 266                 thresh = *bp++;
 267                 ncount = *bp++;
 268                 len -= 7;
 269                 while (--ncount >= 0) {
 270                         ND_TCHECK2(bp[0], 4);
 271                         ND_PRINT((ndo, " [%s ->", ipaddr_string(ndo, laddr)));
 272                         ND_PRINT((ndo, " %s, (%d/%d)]",
 273                                    ipaddr_string(ndo, bp), metric, thresh));
 274                         bp += 4;
 275                         len -= 4;
 276                 }
 277         }
 278         return (0);
 279 trunc:
 280         return (-1);
 281 }
 282
 283 static int
 284 print_neighbors2(netdissect_options *ndo,
 285                  register const u_char *bp, register const u_char *ep,
 286                  register u_int len)
 287 {
 288         const u_char *laddr;
 289         register u_char metric, thresh, flags;
 290         register int ncount;
 291
 292         ND_PRINT((ndo, " (v %d.%d):",
 293                (int)target_level & 0xff,
 294                (int)(target_level >> 8) & 0xff));
 295
 296         while (len > 0 && bp < ep) {
 297                 ND_TCHECK2(bp[0], 8);
 298                 laddr = bp;
 299                 bp += 4;
 300                 metric = *bp++;
 301                 thresh = *bp++;
 302                 flags = *bp++;
 303                 ncount = *bp++;
 304                 len -= 8;
 305                 while (--ncount >= 0 && (len >= 4) && (bp + 4) <= ep) {
 306                         ND_PRINT((ndo, " [%s -> ", ipaddr_string(ndo, laddr)));
 307                         ND_PRINT((ndo, "%s (%d/%d", ipaddr_string(ndo, bp),
 308                                      metric, thresh));
 309                         if (flags & DVMRP_NF_TUNNEL)
 310                                 ND_PRINT((ndo, "/tunnel"));
 311                         if (flags & DVMRP_NF_SRCRT)
 312                                 ND_PRINT((ndo, "/srcrt"));
 313                         if (flags & DVMRP_NF_QUERIER)
 314                                 ND_PRINT((ndo, "/querier"));
 315                         if (flags & DVMRP_NF_DISABLED)
 316                                 ND_PRINT((ndo, "/disabled"));
 317                         if (flags & DVMRP_NF_DOWN)
 318                                 ND_PRINT((ndo, "/down"));
 319                         ND_PRINT((ndo, ")]"));
 320                         bp += 4;
 321                         len -= 4;
 322                 }
 323                 if (ncount != -1) {
 324                         ND_PRINT((ndo, " [|]"));
 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             register const u_char *bp)
 336 {
 337         ND_TCHECK2(bp[0], 12);
 338         ND_PRINT((ndo, " src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4)));
 339         bp += 8;
 340         ND_PRINT((ndo, " timer "));
 341         unsigned_relts_print(ndo, EXTRACT_BE_32BITS(bp));
 342         return (0);
 343 trunc:
 344         return (-1);
 345 }
 346
 347 static int
 348 print_graft(netdissect_options *ndo,
 349             register const u_char *bp)
 350 {
 351         ND_TCHECK2(bp[0], 8);
 352         ND_PRINT((ndo, " src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4)));
 353         return (0);
 354 trunc:
 355         return (-1);
 356 }
 357
 358 static int
 359 print_graft_ack(netdissect_options *ndo,
 360                 register const u_char *bp)
 361 {
 362         ND_TCHECK2(bp[0], 8);
 363         ND_PRINT((ndo, " src %s grp %s", ipaddr_string(ndo, bp), ipaddr_string(ndo, bp + 4)));
 364         return (0);
 365 trunc:
 366         return (-1);
 367 }