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         family = EXTRACT_BE_U_2(ni->rip_family);
 193         if (family != BSD_AFNUM_INET && family != 0) {
 194                 ND_PRINT("\n\t AFI %s, ", tok2str(bsd_af_values, "Unknown (%u)", family));
 195                 print_unknown_data(ndo, p + sizeof(*eh), "\n\t  ", RIP_ROUTELEN - sizeof(*eh));
 196                 return (RIP_ROUTELEN);
 197         }
 198         if (EXTRACT_BE_U_2(ni->rip_mbz1) ||
 199             EXTRACT_BE_U_4(ni->rip_mbz2) ||
 200             EXTRACT_BE_U_4(ni->rip_mbz3)) {
 201                 /* MBZ fields not zero */
 202                 print_unknown_data(ndo, p, "\n\t  ", RIP_ROUTELEN);
 203                 return (RIP_ROUTELEN);
 204         }
 205         if (family == 0) {
 206                 ND_PRINT("\n\t  AFI 0, %s, metric: %u",
 207                         ipaddr_string(ndo, ni->rip_dest),
 208                         EXTRACT_BE_U_4(ni->rip_metric));
 209                 return (RIP_ROUTELEN);
 210         } /* BSD_AFNUM_INET */
 211         ND_PRINT("\n\t  %s, metric: %u",
 212                ipaddr_string(ndo, ni->rip_dest),
 213                EXTRACT_BE_U_4(ni->rip_metric));
 214         return (RIP_ROUTELEN);
 215 }
 216
 217 static unsigned
 218 rip_entry_print_v2(netdissect_options *ndo, const u_char *p,
 219                    unsigned remaining)
 220 {
 221         const struct rip_entry_header *eh = (const struct rip_entry_header *)p;
 222         u_short family;
 223         const struct rip_netinfo_v2 *ni;
 224
 225         if (remaining < sizeof(*eh))
 226                 return (0);
 227         family = EXTRACT_BE_U_2(eh->rip_family);
 228         if (family == 0xFFFF) { /* variable-sized authentication structures */
 229                 uint16_t auth_type = EXTRACT_BE_U_2(eh->rip_tag);
 230
 231                 p += sizeof(*eh);
 232                 remaining -= sizeof(*eh);
 233                 if (auth_type == 2) {
 234                         ND_PRINT("\n\t  Simple Text Authentication data: ");
 235                         if (nd_printzp(ndo, p, RIP_AUTHLEN, p + remaining))
 236                                 return (0);
 237                 } else if (auth_type == 3) {
 238                         const struct rip_auth_crypto_v2 *ch;
 239
 240                         ch = (const struct rip_auth_crypto_v2 *)p;
 241                         if (remaining < sizeof(*ch))
 242                                 return (0);
 243                         ND_PRINT("\n\t  Auth header:");
 244                         ND_PRINT(" Packet Len %u,", EXTRACT_BE_U_2(ch->rip_packet_len));
 245                         ND_PRINT(" Key-ID %u,", EXTRACT_U_1(ch->rip_key_id));
 246                         ND_PRINT(" Auth Data Len %u,", EXTRACT_U_1(ch->rip_auth_data_len));
 247                         ND_PRINT(" SeqNo %u,", EXTRACT_BE_U_4(ch->rip_seq_num));
 248                         ND_PRINT(" MBZ %u,", EXTRACT_BE_U_4(ch->rip_mbz1));
 249                         ND_PRINT(" MBZ %u", EXTRACT_BE_U_4(ch->rip_mbz2));
 250                 } else if (auth_type == 1) {
 251                         ND_PRINT("\n\t  Auth trailer:");
 252                         print_unknown_data(ndo, p, "\n\t  ", remaining);
 253                         return (sizeof(*eh) + remaining); /* AT spans till the packet end */
 254                 } else {
 255                         ND_PRINT("\n\t  Unknown (%u) Authentication data:",
 256                                auth_type);
 257                         print_unknown_data(ndo, p, "\n\t  ", remaining);
 258                         return (sizeof(*eh) + remaining); /* we don't know how long this is, so we go to the packet end */
 259                 }
 260         } else if (family != BSD_AFNUM_INET && family != 0) {
 261                 ND_PRINT("\n\t  AFI %s", tok2str(bsd_af_values, "Unknown (%u)", family));
 262                 print_unknown_data(ndo, p + sizeof(*eh), "\n\t  ", RIP_ROUTELEN - sizeof(*eh));
 263         } else { /* BSD_AFNUM_INET or AFI 0 */
 264                 ni = (const struct rip_netinfo_v2 *)p;
 265                 if (remaining < sizeof(*ni))
 266                         return (0);
 267                 ND_PRINT("\n\t  AFI %s, %15s/%-2d, tag 0x%04x, metric: %u, next-hop: ",
 268                        tok2str(bsd_af_values, "%u", family),
 269                        ipaddr_string(ndo, ni->rip_dest),
 270                        mask2plen(EXTRACT_BE_U_4(ni->rip_dest_mask)),
 271                        EXTRACT_BE_U_2(ni->rip_tag),
 272                        EXTRACT_BE_U_4(ni->rip_metric));
 273                 if (EXTRACT_BE_U_4(ni->rip_router))
 274                         ND_PRINT("%s", ipaddr_string(ndo, ni->rip_router));
 275                 else
 276                         ND_PRINT("self");
 277         }
 278         return (RIP_ROUTELEN);
 279 }
 280
 281 void
 282 rip_print(netdissect_options *ndo,
 283           const u_char *dat, u_int length)
 284 {
 285         const struct rip *rp;
 286         uint8_t vers, cmd;
 287         const u_char *p;
 288         u_int i, j;
 289         unsigned entry_size;
 290
 291         ndo->ndo_protocol = "rip";
 292         if (ndo->ndo_snapend < dat) {
 293                 nd_print_trunc(ndo);
 294                 return;
 295         }
 296         i = ndo->ndo_snapend - dat;
 297         if (i > length)
 298                 i = length;
 299         if (i < sizeof(*rp)) {
 300                 nd_print_trunc(ndo);
 301                 return;
 302         }
 303         i -= sizeof(*rp);
 304
 305         rp = (const struct rip *)dat;
 306
 307         vers = EXTRACT_U_1(rp->rip_vers);
 308         ND_PRINT("%sRIPv%u",
 309                (ndo->ndo_vflag >= 1) ? "\n\t" : "",
 310                vers);
 311
 312         if (vers == 0) {
 313                 /*
 314                  * RFC 1058.
 315                  *
 316                  * XXX - RFC 1058 says
 317                  *
 318                  * 0  Datagrams whose version number is zero are to be ignored.
 319                  *    These are from a previous version of the protocol, whose
 320                  *    packet format was machine-specific.
 321                  *
 322                  * so perhaps we should just dump the packet, in hex.
 323                  */
 324                 print_unknown_data(ndo, (const uint8_t *)&rp->rip_cmd, "\n\t", length);
 325                 return;
 326         }
 327
 328         /* dump version and lets see if we know the commands name*/
 329         cmd = EXTRACT_U_1(rp->rip_cmd);
 330         ND_PRINT(", %s, length: %u",
 331                 tok2str(rip_cmd_values, "unknown command (%u)", cmd),
 332                 length);
 333
 334         if (ndo->ndo_vflag < 1)
 335                 return;
 336
 337         switch (cmd) {
 338
 339         case RIPCMD_REQUEST:
 340         case RIPCMD_RESPONSE:
 341                 switch (vers) {
 342
 343                 case 1:
 344                         j = length / RIP_ROUTELEN;
 345                         ND_PRINT(", routes: %u", j);
 346                         p = (const u_char *)(rp + 1);
 347                         while (i != 0) {
 348                                 entry_size = rip_entry_print_v1(ndo, p, i);
 349                                 if (entry_size == 0) {
 350                                         /* Error */
 351                                         nd_print_trunc(ndo);
 352                                         break;
 353                                 }
 354                                 p += entry_size;
 355                                 i -= entry_size;
 356                         }
 357                         break;
 358
 359                 case 2:
 360                         j = length / RIP_ROUTELEN;
 361                         ND_PRINT(", routes: %u or less", j);
 362                         p = (const u_char *)(rp + 1);
 363                         while (i != 0) {
 364                                 entry_size = rip_entry_print_v2(ndo, p, i);
 365                                 if (entry_size == 0) {
 366                                         /* Error */
 367                                         nd_print_trunc(ndo);
 368                                         break;
 369                                 }
 370 #if 0
 371                                 if (i < entry_size) {
 372                                         ND_PRINT("WTF?");
 373                                         break;
 374                                 }
 375 #endif
 376                                 p += entry_size;
 377                                 i -= entry_size;
 378                         }
 379                         break;
 380
 381                 default:
 382                         ND_PRINT(", unknown version");
 383                         break;
 384                 }
 385                 break;
 386
 387         case RIPCMD_TRACEOFF:
 388         case RIPCMD_POLL:
 389         case RIPCMD_POLLENTRY:
 390                 break;
 391
 392         case RIPCMD_TRACEON:
 393                 /* fall through */
 394         default:
 395                 if (ndo->ndo_vflag <= 1) {
 396                         if (!print_unknown_data(ndo, (const uint8_t *)rp, "\n\t", length))
 397                                 return;
 398                 }
 399                 break;
 400         }
 401         /* do we want to see an additionally hexdump ? */
 402         if (ndo->ndo_vflag> 1) {
 403                 if (!print_unknown_data(ndo, (const uint8_t *)rp, "\n\t", length))
 404                         return;
 405         }
 406 }