The Tcpdump Group git mirrors - tcpdump/blob - print-rip.c

   1 /*
   2  * Copyright (c) 1989, 1990, 1991, 1993, 1994, 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: Routing Information Protocol (RIP) printer */
  23
  24 /* specification: RFC 1058, RFC 2453, RFC 4822 */
  25
  26 #ifdef HAVE_CONFIG_H
  27 #include <config.h>
  28 #endif
  29
  30 #include "netdissect-stdinc.h"
  31
  32 #include <stdio.h>
  33
  34 #include "netdissect.h"
  35 #include "addrtoname.h"
  36 #include "extract.h"
  37
  38 #include "af.h"
  39
  40
  41 /*
  42  * RFC 1058 and RFC 2453 header of packet.
  43  *
  44  *  0                   1                   2                   3 3
  45  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  46  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  47  * | Command (1)   | Version (1)   |           unused              |
  48  * +---------------+---------------+-------------------------------+
  49  */
  50 struct rip {
  51         nd_uint8_t rip_cmd;             /* request/response */
  52         nd_uint8_t rip_vers;            /* protocol version # */
  53         nd_byte    unused[2];           /* unused */
  54 };
  55
  56 #define RIPCMD_REQUEST          1       /* want info */
  57 #define RIPCMD_RESPONSE         2       /* responding to request */
  58 #define RIPCMD_TRACEON          3       /* turn tracing on */
  59 #define RIPCMD_TRACEOFF         4       /* turn it off */
  60 #define RIPCMD_POLL             5       /* want info from everybody */
  61 #define RIPCMD_POLLENTRY        6       /* poll for entry */
  62
  63 static const struct tok rip_cmd_values[] = {
  64     { RIPCMD_REQUEST,           "Request" },
  65     { RIPCMD_RESPONSE,          "Response" },
  66     { RIPCMD_TRACEON,           "Trace on" },
  67     { RIPCMD_TRACEOFF,          "Trace off" },
  68     { RIPCMD_POLL,              "Poll" },
  69     { RIPCMD_POLLENTRY,         "Poll Entry" },
  70     { 0, NULL}
  71 };
  72
  73 #define RIP_AUTHLEN  16
  74 #define RIP_ROUTELEN 20
  75
  76 /*
  77  * First 4 bytes of all RIPv1/RIPv2 entries.
  78  */
  79 struct rip_entry_header {
  80         nd_uint16_t rip_family;
  81         nd_uint16_t rip_tag;
  82 };
  83
  84 /*
  85  * RFC 1058 entry.
  86  *
  87  *  0                   1                   2                   3 3
  88  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  89  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  90  * | Address Family Identifier (2) |       must be zero (2)        |
  91  * +-------------------------------+-------------------------------+
  92  * |                         IP Address (4)                        |
  93  * +---------------------------------------------------------------+
  94  * |                        must be zero (4)                       |
  95  * +---------------------------------------------------------------+
  96  * |                        must be zero (4)                       |
  97  * +---------------------------------------------------------------+
  98  * |                         Metric (4)                            |
  99  * +---------------------------------------------------------------+
 100  */
 101 struct rip_netinfo_v1 {
 102         nd_uint16_t rip_family;
 103         nd_byte     rip_mbz1[2];
 104         nd_ipv4     rip_dest;
 105         nd_byte     rip_mbz2[4];
 106         nd_byte     rip_mbz3[4];
 107         nd_uint32_t rip_metric;         /* cost of route */
 108 };
 109
 110
 111 /*
 112  * RFC 2453 route entry
 113  *
 114  *  0                   1                   2                   3 3
 115  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 116  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 117  * | Address Family Identifier (2) |        Route Tag (2)          |
 118  * +-------------------------------+-------------------------------+
 119  * |                         IP Address (4)                        |
 120  * +---------------------------------------------------------------+
 121  * |                         Subnet Mask (4)                       |
 122  * +---------------------------------------------------------------+
 123  * |                         Next Hop (4)                          |
 124  * +---------------------------------------------------------------+
 125  * |                         Metric (4)                            |
 126  * +---------------------------------------------------------------+
 127  *
 128  */
 129
 130 struct rip_netinfo_v2 {
 131         nd_uint16_t rip_family;
 132         nd_uint16_t rip_tag;
 133         nd_ipv4     rip_dest;
 134         nd_uint32_t rip_dest_mask;
 135         nd_ipv4     rip_router;
 136         nd_uint32_t rip_metric;         /* cost of route */
 137 };
 138
 139 /*
 140  * RFC 2453 authentication entry
 141  *
 142  *  0                   1                   2                   3 3
 143  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 144  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 145  * |            0xFFFF             |    Authentication Type (2)    |
 146  * +-------------------------------+-------------------------------+
 147  * -                      Authentication (16)                      -
 148  * +---------------------------------------------------------------+
 149  */
 150
 151 struct rip_auth_v2 {
 152         nd_uint16_t rip_family;
 153         nd_uint16_t rip_tag;
 154         nd_byte     rip_auth[16];
 155 };
 156
 157 /*
 158  * RFC 4822 Cryptographic Authentication entry.
 159  *
 160  *  0                   1                   2                   3 3
 161  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 162  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 163  * |     RIPv2 Packet Length       |   Key ID      | Auth Data Len |
 164  * +---------------+---------------+---------------+---------------+
 165  * |               Sequence Number (non-decreasing)                |
 166  * +---------------+---------------+---------------+---------------+
 167  * |                      reserved must be zero                    |
 168  * +---------------+---------------+---------------+---------------+
 169  * |                      reserved must be zero                    |
 170  * +---------------+---------------+---------------+---------------+
 171  */
 172 struct rip_auth_crypto_v2 {
 173         nd_uint16_t rip_packet_len;
 174         nd_uint8_t  rip_key_id;
 175         nd_uint8_t  rip_auth_data_len;
 176         nd_uint32_t rip_seq_num;
 177         nd_byte     rip_mbz1[4];
 178         nd_byte     rip_mbz2[4];
 179 };
 180
 181 static unsigned
 182 rip_entry_print_v1(netdissect_options *ndo, const u_char *p,
 183                    unsigned remaining)
 184 {
 185         const struct rip_entry_header *eh = (const struct rip_entry_header *)p;
 186         u_short family;
 187         const struct rip_netinfo_v1 *ni = (const struct rip_netinfo_v1 *)p;
 188
 189         /* RFC 1058 */
 190         if (remaining < RIP_ROUTELEN)
 191                 return (0);
 192         ND_TCHECK_SIZE(ni);
 193         family = EXTRACT_BE_U_2(ni->rip_family);
 194         if (family != BSD_AFNUM_INET && family != 0) {
 195                 ND_PRINT("\n\t AFI %s, ", tok2str(bsd_af_values, "Unknown (%u)", family));
 196                 print_unknown_data(ndo, p + sizeof(*eh), "\n\t  ", RIP_ROUTELEN - sizeof(*eh));
 197                 return (RIP_ROUTELEN);
 198         }
 199         if (EXTRACT_BE_U_2(ni->rip_mbz1) ||
 200             EXTRACT_BE_U_4(ni->rip_mbz2) ||
 201             EXTRACT_BE_U_4(ni->rip_mbz3)) {
 202                 /* MBZ fields not zero */
 203                 print_unknown_data(ndo, p, "\n\t  ", RIP_ROUTELEN);
 204                 return (RIP_ROUTELEN);
 205         }
 206         if (family == 0) {
 207                 ND_PRINT("\n\t  AFI 0, %s, metric: %u",
 208                          ipaddr_string(ndo, ni->rip_dest),
 209                          EXTRACT_BE_U_4(ni->rip_metric));
 210                 return (RIP_ROUTELEN);
 211         } /* BSD_AFNUM_INET */
 212         ND_PRINT("\n\t  %s, metric: %u",
 213                  ipaddr_string(ndo, ni->rip_dest),
 214                  EXTRACT_BE_U_4(ni->rip_metric));
 215         return (RIP_ROUTELEN);
 216 trunc:
 217         return 0;
 218 }
 219
 220 static unsigned
 221 rip_entry_print_v2(netdissect_options *ndo, const u_char *p,
 222                    unsigned remaining)
 223 {
 224         const struct rip_entry_header *eh = (const struct rip_entry_header *)p;
 225         u_short family;
 226         const struct rip_netinfo_v2 *ni;
 227
 228         if (remaining < sizeof(*eh))
 229                 return (0);
 230         ND_TCHECK_SIZE(eh);
 231         family = EXTRACT_BE_U_2(eh->rip_family);
 232         if (family == 0xFFFF) { /* variable-sized authentication structures */
 233                 uint16_t auth_type = EXTRACT_BE_U_2(eh->rip_tag);
 234
 235                 p += sizeof(*eh);
 236                 remaining -= sizeof(*eh);
 237                 if (auth_type == 2) {
 238                         ND_PRINT("\n\t  Simple Text Authentication data: ");
 239                         if (nd_printzp(ndo, p, RIP_AUTHLEN, p + remaining))
 240                                 return (0);
 241                 } else if (auth_type == 3) {
 242                         const struct rip_auth_crypto_v2 *ch;
 243
 244                         ch = (const struct rip_auth_crypto_v2 *)p;
 245                         ND_TCHECK_SIZE(ch);
 246                         if (remaining < sizeof(*ch))
 247                                 return (0);
 248                         ND_PRINT("\n\t  Auth header:");
 249                         ND_PRINT(" Packet Len %u,", EXTRACT_BE_U_2(ch->rip_packet_len));
 250                         ND_PRINT(" Key-ID %u,", EXTRACT_U_1(ch->rip_key_id));
 251                         ND_PRINT(" Auth Data Len %u,", EXTRACT_U_1(ch->rip_auth_data_len));
 252                         ND_PRINT(" SeqNo %u,", EXTRACT_BE_U_4(ch->rip_seq_num));
 253                         ND_PRINT(" MBZ %u,", EXTRACT_BE_U_4(ch->rip_mbz1));
 254                         ND_PRINT(" MBZ %u", EXTRACT_BE_U_4(ch->rip_mbz2));
 255                 } else if (auth_type == 1) {
 256                         ND_PRINT("\n\t  Auth trailer:");
 257                         print_unknown_data(ndo, p, "\n\t  ", remaining);
 258                         return (sizeof(*eh) + remaining); /* AT spans till the packet end */
 259                 } else {
 260                         ND_PRINT("\n\t  Unknown (%u) Authentication data:",
 261                                  auth_type);
 262                         print_unknown_data(ndo, p, "\n\t  ", remaining);
 263                         return (sizeof(*eh) + remaining); /* we don't know how long this is, so we go to the packet end */
 264                 }
 265         } else if (family != BSD_AFNUM_INET && family != 0) {
 266                 ND_PRINT("\n\t  AFI %s", tok2str(bsd_af_values, "Unknown (%u)", family));
 267                 print_unknown_data(ndo, p + sizeof(*eh), "\n\t  ", RIP_ROUTELEN - sizeof(*eh));
 268         } else { /* BSD_AFNUM_INET or AFI 0 */
 269                 ni = (const struct rip_netinfo_v2 *)p;
 270                 ND_TCHECK_SIZE(ni);
 271                 if (remaining < sizeof(*ni))
 272                         return (0);
 273                 ND_PRINT("\n\t  AFI %s, %15s/%-2d, tag 0x%04x, metric: %u, next-hop: ",
 274                          tok2str(bsd_af_values, "%u", family),
 275                          ipaddr_string(ndo, ni->rip_dest),
 276                          mask2plen(EXTRACT_BE_U_4(ni->rip_dest_mask)),
 277                          EXTRACT_BE_U_2(ni->rip_tag),
 278                          EXTRACT_BE_U_4(ni->rip_metric));
 279                 if (EXTRACT_BE_U_4(ni->rip_router))
 280                         ND_PRINT("%s", ipaddr_string(ndo, ni->rip_router));
 281                 else
 282                         ND_PRINT("self");
 283         }
 284         return (RIP_ROUTELEN);
 285 trunc:
 286         return 0;
 287 }
 288
 289 void
 290 rip_print(netdissect_options *ndo,
 291           const u_char *dat, u_int length)
 292 {
 293         const struct rip *rp;
 294         uint8_t vers, cmd;
 295         const u_char *p;
 296         u_int len, routecount;
 297         unsigned entry_size;
 298
 299         ndo->ndo_protocol = "rip";
 300         if (ndo->ndo_snapend < dat) {
 301                 nd_print_trunc(ndo);
 302                 return;
 303         }
 304         len = ndo->ndo_snapend - dat;
 305         if (len > length)
 306                 len = length;
 307         if (len < sizeof(*rp)) {
 308                 nd_print_trunc(ndo);
 309                 return;
 310         }
 311         len -= sizeof(*rp);
 312
 313         rp = (const struct rip *)dat;
 314
 315         ND_TCHECK_SIZE(rp);
 316         vers = EXTRACT_U_1(rp->rip_vers);
 317         ND_PRINT("%sRIPv%u",
 318                  (ndo->ndo_vflag >= 1) ? "\n\t" : "",
 319                  vers);
 320
 321         if (vers == 0) {
 322                 /*
 323                  * RFC 1058.
 324                  *
 325                  * XXX - RFC 1058 says
 326                  *
 327                  * 0  Datagrams whose version number is zero are to be ignored.
 328                  *    These are from a previous version of the protocol, whose
 329                  *    packet format was machine-specific.
 330                  *
 331                  * so perhaps we should just dump the packet, in hex.
 332                  */
 333                 print_unknown_data(ndo, (const uint8_t *)&rp->rip_cmd, "\n\t", length);
 334                 return;
 335         }
 336
 337         /* dump version and lets see if we know the commands name*/
 338         cmd = EXTRACT_U_1(rp->rip_cmd);
 339         ND_PRINT(", %s, length: %u",
 340                 tok2str(rip_cmd_values, "unknown command (%u)", cmd),
 341                 length);
 342
 343         if (ndo->ndo_vflag < 1)
 344                 return;
 345
 346         switch (cmd) {
 347
 348         case RIPCMD_REQUEST:
 349         case RIPCMD_RESPONSE:
 350                 switch (vers) {
 351
 352                 case 1:
 353                         routecount = length / RIP_ROUTELEN;
 354                         ND_PRINT(", routes: %u", routecount);
 355                         p = (const u_char *)(rp + 1);
 356                         while (len != 0) {
 357                                 entry_size = rip_entry_print_v1(ndo, p, len);
 358                                 if (entry_size == 0) {
 359                                         /* Error */
 360                                         nd_print_trunc(ndo);
 361                                         break;
 362                                 }
 363                                 if (len < entry_size) {
 364                                         ND_PRINT(" [remaining entries length %u < %u]",
 365                                                  len, entry_size);
 366                                         nd_print_invalid(ndo);
 367                                         break;
 368                                 }
 369                                 p += entry_size;
 370                                 len -= entry_size;
 371                         }
 372                         break;
 373
 374                 case 2:
 375                         routecount = length / RIP_ROUTELEN;
 376                         ND_PRINT(", routes: %u or less", routecount);
 377                         p = (const u_char *)(rp + 1);
 378                         while (len != 0) {
 379                                 entry_size = rip_entry_print_v2(ndo, p, len);
 380                                 if (entry_size == 0) {
 381                                         /* Error */
 382                                         nd_print_trunc(ndo);
 383                                         break;
 384                                 }
 385                                 if (len < entry_size) {
 386                                         ND_PRINT(" [remaining entries length %u < %u]",
 387                                                  len, entry_size);
 388                                         nd_print_invalid(ndo);
 389                                         break;
 390                                 }
 391                                 p += entry_size;
 392                                 len -= entry_size;
 393                         }
 394                         break;
 395
 396                 default:
 397                         ND_PRINT(", unknown version");
 398                         break;
 399                 }
 400                 break;
 401
 402         case RIPCMD_TRACEOFF:
 403         case RIPCMD_POLL:
 404         case RIPCMD_POLLENTRY:
 405                 break;
 406
 407         case RIPCMD_TRACEON:
 408                 /* fall through */
 409         default:
 410                 if (ndo->ndo_vflag <= 1) {
 411                         if (!print_unknown_data(ndo, (const uint8_t *)rp, "\n\t", length))
 412                                 return;
 413                 }
 414                 break;
 415         }
 416         /* do we want to see an additionally hexdump ? */
 417         if (ndo->ndo_vflag> 1) {
 418                 if (!print_unknown_data(ndo, (const uint8_t *)rp, "\n\t", length))
 419                         return;
 420         }
 421 trunc:
 422         return;
 423 }