contrib/tcpdump/print-eigrp.c

   1 /*
   2  * Copyright (c) 1998-2004  Hannes Gredler <hannes@tcpdump.org>
   3  *      The TCPDUMP project
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code
   7  * distributions retain the above copyright notice and this paragraph
   8  * in its entirety, and (2) distributions including binary code include
   9  * the above copyright notice and this paragraph in its entirety in
  10  * the documentation or other materials provided with the distribution.
  11  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
  12  * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
  13  * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  14  * FOR A PARTICULAR PURPOSE.
  15  */
  16
  17 /* \summary: Enhanced Interior Gateway Routing Protocol (EIGRP) printer */
  18
  19 #ifdef HAVE_CONFIG_H
  20 #include "config.h"
  21 #endif
  22
  23 #include <netdissect-stdinc.h>
  24
  25 #include <string.h>
  26
  27 #include "netdissect.h"
  28 #include "extract.h"
  29 #include "addrtoname.h"
  30
  31 /*
  32  * packet format documented at
  33  * http://www.rhyshaden.com/eigrp.htm
  34  */
  35
  36 struct eigrp_common_header {
  37     uint8_t version;
  38     uint8_t opcode;
  39     uint8_t checksum[2];
  40     uint8_t flags[4];
  41     uint8_t seq[4];
  42     uint8_t ack[4];
  43     uint8_t asn[4];
  44 };
  45
  46 #define EIGRP_VERSION                        2
  47
  48 #define EIGRP_OPCODE_UPDATE                  1
  49 #define EIGRP_OPCODE_QUERY                   3
  50 #define EIGRP_OPCODE_REPLY                   4
  51 #define EIGRP_OPCODE_HELLO                   5
  52 #define EIGRP_OPCODE_IPXSAP                  6
  53 #define EIGRP_OPCODE_PROBE                   7
  54
  55 static const struct tok eigrp_opcode_values[] = {
  56     { EIGRP_OPCODE_UPDATE, "Update" },
  57     { EIGRP_OPCODE_QUERY, "Query" },
  58     { EIGRP_OPCODE_REPLY, "Reply" },
  59     { EIGRP_OPCODE_HELLO, "Hello" },
  60     { EIGRP_OPCODE_IPXSAP, "IPX SAP" },
  61     { EIGRP_OPCODE_PROBE, "Probe" },
  62     { 0, NULL}
  63 };
  64
  65 static const struct tok eigrp_common_header_flag_values[] = {
  66     { 0x01, "Init" },
  67     { 0x02, "Conditionally Received" },
  68     { 0, NULL}
  69 };
  70
  71 struct eigrp_tlv_header {
  72     uint8_t type[2];
  73     uint8_t length[2];
  74 };
  75
  76 #define EIGRP_TLV_GENERAL_PARM   0x0001
  77 #define EIGRP_TLV_AUTH           0x0002
  78 #define EIGRP_TLV_SEQ            0x0003
  79 #define EIGRP_TLV_SW_VERSION     0x0004
  80 #define EIGRP_TLV_MCAST_SEQ      0x0005
  81 #define EIGRP_TLV_IP_INT         0x0102
  82 #define EIGRP_TLV_IP_EXT         0x0103
  83 #define EIGRP_TLV_AT_INT         0x0202
  84 #define EIGRP_TLV_AT_EXT         0x0203
  85 #define EIGRP_TLV_AT_CABLE_SETUP 0x0204
  86 #define EIGRP_TLV_IPX_INT        0x0302
  87 #define EIGRP_TLV_IPX_EXT        0x0303
  88
  89 static const struct tok eigrp_tlv_values[] = {
  90     { EIGRP_TLV_GENERAL_PARM, "General Parameters"},
  91     { EIGRP_TLV_AUTH, "Authentication"},
  92     { EIGRP_TLV_SEQ, "Sequence"},
  93     { EIGRP_TLV_SW_VERSION, "Software Version"},
  94     { EIGRP_TLV_MCAST_SEQ, "Next Multicast Sequence"},
  95     { EIGRP_TLV_IP_INT, "IP Internal routes"},
  96     { EIGRP_TLV_IP_EXT, "IP External routes"},
  97     { EIGRP_TLV_AT_INT, "AppleTalk Internal routes"},
  98     { EIGRP_TLV_AT_EXT, "AppleTalk External routes"},
  99     { EIGRP_TLV_AT_CABLE_SETUP, "AppleTalk Cable setup"},
 100     { EIGRP_TLV_IPX_INT, "IPX Internal routes"},
 101     { EIGRP_TLV_IPX_EXT, "IPX External routes"},
 102     { 0, NULL}
 103 };
 104
 105 struct eigrp_tlv_general_parm_t {
 106     uint8_t k1;
 107     uint8_t k2;
 108     uint8_t k3;
 109     uint8_t k4;
 110     uint8_t k5;
 111     uint8_t res;
 112     uint8_t holdtime[2];
 113 };
 114
 115 struct eigrp_tlv_sw_version_t {
 116     uint8_t ios_major;
 117     uint8_t ios_minor;
 118     uint8_t eigrp_major;
 119     uint8_t eigrp_minor;
 120 };
 121
 122 struct eigrp_tlv_ip_int_t {
 123     uint8_t nexthop[4];
 124     uint8_t delay[4];
 125     uint8_t bandwidth[4];
 126     uint8_t mtu[3];
 127     uint8_t hopcount;
 128     uint8_t reliability;
 129     uint8_t load;
 130     uint8_t reserved[2];
 131     uint8_t plen;
 132     uint8_t destination; /* variable length [1-4] bytes encoding */
 133 };
 134
 135 struct eigrp_tlv_ip_ext_t {
 136     uint8_t nexthop[4];
 137     uint8_t origin_router[4];
 138     uint8_t origin_as[4];
 139     uint8_t tag[4];
 140     uint8_t metric[4];
 141     uint8_t reserved[2];
 142     uint8_t proto_id;
 143     uint8_t flags;
 144     uint8_t delay[4];
 145     uint8_t bandwidth[4];
 146     uint8_t mtu[3];
 147     uint8_t hopcount;
 148     uint8_t reliability;
 149     uint8_t load;
 150     uint8_t reserved2[2];
 151     uint8_t plen;
 152     uint8_t destination; /* variable length [1-4] bytes encoding */
 153 };
 154
 155 struct eigrp_tlv_at_cable_setup_t {
 156     uint8_t cable_start[2];
 157     uint8_t cable_end[2];
 158     uint8_t router_id[4];
 159 };
 160
 161 struct eigrp_tlv_at_int_t {
 162     uint8_t nexthop[4];
 163     uint8_t delay[4];
 164     uint8_t bandwidth[4];
 165     uint8_t mtu[3];
 166     uint8_t hopcount;
 167     uint8_t reliability;
 168     uint8_t load;
 169     uint8_t reserved[2];
 170     uint8_t cable_start[2];
 171     uint8_t cable_end[2];
 172 };
 173
 174 struct eigrp_tlv_at_ext_t {
 175     uint8_t nexthop[4];
 176     uint8_t origin_router[4];
 177     uint8_t origin_as[4];
 178     uint8_t tag[4];
 179     uint8_t proto_id;
 180     uint8_t flags;
 181     uint8_t metric[2];
 182     uint8_t delay[4];
 183     uint8_t bandwidth[4];
 184     uint8_t mtu[3];
 185     uint8_t hopcount;
 186     uint8_t reliability;
 187     uint8_t load;
 188     uint8_t reserved2[2];
 189     uint8_t cable_start[2];
 190     uint8_t cable_end[2];
 191 };
 192
 193 static const struct tok eigrp_ext_proto_id_values[] = {
 194     { 0x01, "IGRP" },
 195     { 0x02, "EIGRP" },
 196     { 0x03, "Static" },
 197     { 0x04, "RIP" },
 198     { 0x05, "Hello" },
 199     { 0x06, "OSPF" },
 200     { 0x07, "IS-IS" },
 201     { 0x08, "EGP" },
 202     { 0x09, "BGP" },
 203     { 0x0a, "IDRP" },
 204     { 0x0b, "Connected" },
 205     { 0, NULL}
 206 };
 207
 208 void
 209 eigrp_print(netdissect_options *ndo, register const u_char *pptr, register u_int len)
 210 {
 211     const struct eigrp_common_header *eigrp_com_header;
 212     const struct eigrp_tlv_header *eigrp_tlv_header;
 213     const u_char *tptr,*tlv_tptr;
 214     u_int tlen,eigrp_tlv_len,eigrp_tlv_type,tlv_tlen, byte_length, bit_length;
 215     uint8_t prefix[4];
 216
 217     union {
 218         const struct eigrp_tlv_general_parm_t *eigrp_tlv_general_parm;
 219         const struct eigrp_tlv_sw_version_t *eigrp_tlv_sw_version;
 220         const struct eigrp_tlv_ip_int_t *eigrp_tlv_ip_int;
 221         const struct eigrp_tlv_ip_ext_t *eigrp_tlv_ip_ext;
 222         const struct eigrp_tlv_at_cable_setup_t *eigrp_tlv_at_cable_setup;
 223         const struct eigrp_tlv_at_int_t *eigrp_tlv_at_int;
 224         const struct eigrp_tlv_at_ext_t *eigrp_tlv_at_ext;
 225     } tlv_ptr;
 226
 227     tptr=pptr;
 228     eigrp_com_header = (const struct eigrp_common_header *)pptr;
 229     ND_TCHECK(*eigrp_com_header);
 230
 231     /*
 232      * Sanity checking of the header.
 233      */
 234     if (eigrp_com_header->version != EIGRP_VERSION) {
 235         ND_PRINT((ndo, "EIGRP version %u packet not supported",eigrp_com_header->version));
 236         return;
 237     }
 238
 239     /* in non-verbose mode just lets print the basic Message Type*/
 240     if (ndo->ndo_vflag < 1) {
 241         ND_PRINT((ndo, "EIGRP %s, length: %u",
 242                tok2str(eigrp_opcode_values, "unknown (%u)",eigrp_com_header->opcode),
 243                len));
 244         return;
 245     }
 246
 247     /* ok they seem to want to know everything - lets fully decode it */
 248
 249     tlen=len-sizeof(struct eigrp_common_header);
 250
 251     /* FIXME print other header info */
 252     ND_PRINT((ndo, "\n\tEIGRP v%u, opcode: %s (%u), chksum: 0x%04x, Flags: [%s]\n\tseq: 0x%08x, ack: 0x%08x, AS: %u, length: %u",
 253            eigrp_com_header->version,
 254            tok2str(eigrp_opcode_values, "unknown, type: %u",eigrp_com_header->opcode),
 255            eigrp_com_header->opcode,
 256            EXTRACT_16BITS(&eigrp_com_header->checksum),
 257            tok2str(eigrp_common_header_flag_values,
 258                    "none",
 259                    EXTRACT_32BITS(&eigrp_com_header->flags)),
 260            EXTRACT_32BITS(&eigrp_com_header->seq),
 261            EXTRACT_32BITS(&eigrp_com_header->ack),
 262            EXTRACT_32BITS(&eigrp_com_header->asn),
 263            tlen));
 264
 265     tptr+=sizeof(const struct eigrp_common_header);
 266
 267     while(tlen>0) {
 268         /* did we capture enough for fully decoding the object header ? */
 269         ND_TCHECK2(*tptr, sizeof(struct eigrp_tlv_header));
 270
 271         eigrp_tlv_header = (const struct eigrp_tlv_header *)tptr;
 272         eigrp_tlv_len=EXTRACT_16BITS(&eigrp_tlv_header->length);
 273         eigrp_tlv_type=EXTRACT_16BITS(&eigrp_tlv_header->type);
 274
 275
 276         if (eigrp_tlv_len < sizeof(struct eigrp_tlv_header) ||
 277             eigrp_tlv_len > tlen) {
 278             print_unknown_data(ndo,tptr+sizeof(struct eigrp_tlv_header),"\n\t    ",tlen);
 279             return;
 280         }
 281
 282         ND_PRINT((ndo, "\n\t  %s TLV (0x%04x), length: %u",
 283                tok2str(eigrp_tlv_values,
 284                        "Unknown",
 285                        eigrp_tlv_type),
 286                eigrp_tlv_type,
 287                eigrp_tlv_len));
 288
 289         tlv_tptr=tptr+sizeof(struct eigrp_tlv_header);
 290         tlv_tlen=eigrp_tlv_len-sizeof(struct eigrp_tlv_header);
 291
 292         /* did we capture enough for fully decoding the object ? */
 293         ND_TCHECK2(*tptr, eigrp_tlv_len);
 294
 295         switch(eigrp_tlv_type) {
 296
 297         case EIGRP_TLV_GENERAL_PARM:
 298             tlv_ptr.eigrp_tlv_general_parm = (const struct eigrp_tlv_general_parm_t *)tlv_tptr;
 299
 300             ND_PRINT((ndo, "\n\t    holdtime: %us, k1 %u, k2 %u, k3 %u, k4 %u, k5 %u",
 301                    EXTRACT_16BITS(tlv_ptr.eigrp_tlv_general_parm->holdtime),
 302                    tlv_ptr.eigrp_tlv_general_parm->k1,
 303                    tlv_ptr.eigrp_tlv_general_parm->k2,
 304                    tlv_ptr.eigrp_tlv_general_parm->k3,
 305                    tlv_ptr.eigrp_tlv_general_parm->k4,
 306                    tlv_ptr.eigrp_tlv_general_parm->k5));
 307             break;
 308
 309         case EIGRP_TLV_SW_VERSION:
 310             tlv_ptr.eigrp_tlv_sw_version = (const struct eigrp_tlv_sw_version_t *)tlv_tptr;
 311
 312             ND_PRINT((ndo, "\n\t    IOS version: %u.%u, EIGRP version %u.%u",
 313                    tlv_ptr.eigrp_tlv_sw_version->ios_major,
 314                    tlv_ptr.eigrp_tlv_sw_version->ios_minor,
 315                    tlv_ptr.eigrp_tlv_sw_version->eigrp_major,
 316                    tlv_ptr.eigrp_tlv_sw_version->eigrp_minor));
 317             break;
 318
 319         case EIGRP_TLV_IP_INT:
 320             tlv_ptr.eigrp_tlv_ip_int = (const struct eigrp_tlv_ip_int_t *)tlv_tptr;
 321
 322             bit_length = tlv_ptr.eigrp_tlv_ip_int->plen;
 323             if (bit_length > 32) {
 324                 ND_PRINT((ndo, "\n\t    illegal prefix length %u",bit_length));
 325                 break;
 326             }
 327             byte_length = (bit_length + 7) / 8; /* variable length encoding */
 328             memset(prefix, 0, 4);
 329             memcpy(prefix,&tlv_ptr.eigrp_tlv_ip_int->destination,byte_length);
 330
 331             ND_PRINT((ndo, "\n\t    IPv4 prefix: %15s/%u, nexthop: ",
 332                    ipaddr_string(ndo, prefix),
 333                    bit_length));
 334             if (EXTRACT_32BITS(&tlv_ptr.eigrp_tlv_ip_int->nexthop) == 0)
 335                 ND_PRINT((ndo, "self"));
 336             else
 337                 ND_PRINT((ndo, "%s",ipaddr_string(ndo, &tlv_ptr.eigrp_tlv_ip_int->nexthop)));
 338
 339             ND_PRINT((ndo, "\n\t      delay %u ms, bandwidth %u Kbps, mtu %u, hop %u, reliability %u, load %u",
 340                    (EXTRACT_32BITS(&tlv_ptr.eigrp_tlv_ip_int->delay)/100),
 341                    EXTRACT_32BITS(&tlv_ptr.eigrp_tlv_ip_int->bandwidth),
 342                    EXTRACT_24BITS(&tlv_ptr.eigrp_tlv_ip_int->mtu),
 343                    tlv_ptr.eigrp_tlv_ip_int->hopcount,
 344                    tlv_ptr.eigrp_tlv_ip_int->reliability,
 345                    tlv_ptr.eigrp_tlv_ip_int->load));
 346             break;
 347
 348         case EIGRP_TLV_IP_EXT:
 349             tlv_ptr.eigrp_tlv_ip_ext = (const struct eigrp_tlv_ip_ext_t *)tlv_tptr;
 350
 351             bit_length = tlv_ptr.eigrp_tlv_ip_ext->plen;
 352             if (bit_length > 32) {
 353                 ND_PRINT((ndo, "\n\t    illegal prefix length %u",bit_length));
 354                 break;
 355             }
 356             byte_length = (bit_length + 7) / 8; /* variable length encoding */
 357             memset(prefix, 0, 4);
 358             memcpy(prefix,&tlv_ptr.eigrp_tlv_ip_ext->destination,byte_length);
 359
 360             ND_PRINT((ndo, "\n\t    IPv4 prefix: %15s/%u, nexthop: ",
 361                    ipaddr_string(ndo, prefix),
 362                    bit_length));
 363             if (EXTRACT_32BITS(&tlv_ptr.eigrp_tlv_ip_ext->nexthop) == 0)
 364                 ND_PRINT((ndo, "self"));
 365             else
 366                 ND_PRINT((ndo, "%s",ipaddr_string(ndo, &tlv_ptr.eigrp_tlv_ip_ext->nexthop)));
 367
 368             ND_PRINT((ndo, "\n\t      origin-router %s, origin-as %u, origin-proto %s, flags [0x%02x], tag 0x%08x, metric %u",
 369                    ipaddr_string(ndo, tlv_ptr.eigrp_tlv_ip_ext->origin_router),
 370                    EXTRACT_32BITS(tlv_ptr.eigrp_tlv_ip_ext->origin_as),
 371                    tok2str(eigrp_ext_proto_id_values,"unknown",tlv_ptr.eigrp_tlv_ip_ext->proto_id),
 372                    tlv_ptr.eigrp_tlv_ip_ext->flags,
 373                    EXTRACT_32BITS(tlv_ptr.eigrp_tlv_ip_ext->tag),
 374                    EXTRACT_32BITS(tlv_ptr.eigrp_tlv_ip_ext->metric)));
 375
 376             ND_PRINT((ndo, "\n\t      delay %u ms, bandwidth %u Kbps, mtu %u, hop %u, reliability %u, load %u",
 377                    (EXTRACT_32BITS(&tlv_ptr.eigrp_tlv_ip_ext->delay)/100),
 378                    EXTRACT_32BITS(&tlv_ptr.eigrp_tlv_ip_ext->bandwidth),
 379                    EXTRACT_24BITS(&tlv_ptr.eigrp_tlv_ip_ext->mtu),
 380                    tlv_ptr.eigrp_tlv_ip_ext->hopcount,
 381                    tlv_ptr.eigrp_tlv_ip_ext->reliability,
 382                    tlv_ptr.eigrp_tlv_ip_ext->load));
 383             break;
 384
 385         case EIGRP_TLV_AT_CABLE_SETUP:
 386             tlv_ptr.eigrp_tlv_at_cable_setup = (const struct eigrp_tlv_at_cable_setup_t *)tlv_tptr;
 387
 388             ND_PRINT((ndo, "\n\t    Cable-range: %u-%u, Router-ID %u",
 389                    EXTRACT_16BITS(&tlv_ptr.eigrp_tlv_at_cable_setup->cable_start),
 390                    EXTRACT_16BITS(&tlv_ptr.eigrp_tlv_at_cable_setup->cable_end),
 391                    EXTRACT_32BITS(&tlv_ptr.eigrp_tlv_at_cable_setup->router_id)));
 392             break;
 393
 394         case EIGRP_TLV_AT_INT:
 395             tlv_ptr.eigrp_tlv_at_int = (const struct eigrp_tlv_at_int_t *)tlv_tptr;
 396
 397             ND_PRINT((ndo, "\n\t     Cable-Range: %u-%u, nexthop: ",
 398                    EXTRACT_16BITS(&tlv_ptr.eigrp_tlv_at_int->cable_start),
 399                    EXTRACT_16BITS(&tlv_ptr.eigrp_tlv_at_int->cable_end)));
 400
 401             if (EXTRACT_32BITS(&tlv_ptr.eigrp_tlv_at_int->nexthop) == 0)
 402                 ND_PRINT((ndo, "self"));
 403             else
 404                 ND_PRINT((ndo, "%u.%u",
 405                        EXTRACT_16BITS(&tlv_ptr.eigrp_tlv_at_int->nexthop),
 406                        EXTRACT_16BITS(&tlv_ptr.eigrp_tlv_at_int->nexthop[2])));
 407
 408             ND_PRINT((ndo, "\n\t      delay %u ms, bandwidth %u Kbps, mtu %u, hop %u, reliability %u, load %u",
 409                    (EXTRACT_32BITS(&tlv_ptr.eigrp_tlv_at_int->delay)/100),
 410                    EXTRACT_32BITS(&tlv_ptr.eigrp_tlv_at_int->bandwidth),
 411                    EXTRACT_24BITS(&tlv_ptr.eigrp_tlv_at_int->mtu),
 412                    tlv_ptr.eigrp_tlv_at_int->hopcount,
 413                    tlv_ptr.eigrp_tlv_at_int->reliability,
 414                    tlv_ptr.eigrp_tlv_at_int->load));
 415             break;
 416
 417         case EIGRP_TLV_AT_EXT:
 418             tlv_ptr.eigrp_tlv_at_ext = (const struct eigrp_tlv_at_ext_t *)tlv_tptr;
 419
 420             ND_PRINT((ndo, "\n\t     Cable-Range: %u-%u, nexthop: ",
 421                    EXTRACT_16BITS(&tlv_ptr.eigrp_tlv_at_ext->cable_start),
 422                    EXTRACT_16BITS(&tlv_ptr.eigrp_tlv_at_ext->cable_end)));
 423
 424             if (EXTRACT_32BITS(&tlv_ptr.eigrp_tlv_at_ext->nexthop) == 0)
 425                 ND_PRINT((ndo, "self"));
 426             else
 427                 ND_PRINT((ndo, "%u.%u",
 428                        EXTRACT_16BITS(&tlv_ptr.eigrp_tlv_at_ext->nexthop),
 429                        EXTRACT_16BITS(&tlv_ptr.eigrp_tlv_at_ext->nexthop[2])));
 430
 431             ND_PRINT((ndo, "\n\t      origin-router %u, origin-as %u, origin-proto %s, flags [0x%02x], tag 0x%08x, metric %u",
 432                    EXTRACT_32BITS(tlv_ptr.eigrp_tlv_at_ext->origin_router),
 433                    EXTRACT_32BITS(tlv_ptr.eigrp_tlv_at_ext->origin_as),
 434                    tok2str(eigrp_ext_proto_id_values,"unknown",tlv_ptr.eigrp_tlv_at_ext->proto_id),
 435                    tlv_ptr.eigrp_tlv_at_ext->flags,
 436                    EXTRACT_32BITS(tlv_ptr.eigrp_tlv_at_ext->tag),
 437                    EXTRACT_16BITS(tlv_ptr.eigrp_tlv_at_ext->metric)));
 438
 439             ND_PRINT((ndo, "\n\t      delay %u ms, bandwidth %u Kbps, mtu %u, hop %u, reliability %u, load %u",
 440                    (EXTRACT_32BITS(&tlv_ptr.eigrp_tlv_at_ext->delay)/100),
 441                    EXTRACT_32BITS(&tlv_ptr.eigrp_tlv_at_ext->bandwidth),
 442                    EXTRACT_24BITS(&tlv_ptr.eigrp_tlv_at_ext->mtu),
 443                    tlv_ptr.eigrp_tlv_at_ext->hopcount,
 444                    tlv_ptr.eigrp_tlv_at_ext->reliability,
 445                    tlv_ptr.eigrp_tlv_at_ext->load));
 446             break;
 447
 448             /*
 449              * FIXME those are the defined TLVs that lack a decoder
 450              * you are welcome to contribute code ;-)
 451              */
 452
 453         case EIGRP_TLV_AUTH:
 454         case EIGRP_TLV_SEQ:
 455         case EIGRP_TLV_MCAST_SEQ:
 456         case EIGRP_TLV_IPX_INT:
 457         case EIGRP_TLV_IPX_EXT:
 458
 459         default:
 460             if (ndo->ndo_vflag <= 1)
 461                 print_unknown_data(ndo,tlv_tptr,"\n\t    ",tlv_tlen);
 462             break;
 463         }
 464         /* do we want to see an additionally hexdump ? */
 465         if (ndo->ndo_vflag > 1)
 466             print_unknown_data(ndo,tptr+sizeof(struct eigrp_tlv_header),"\n\t    ",
 467                                eigrp_tlv_len-sizeof(struct eigrp_tlv_header));
 468
 469         tptr+=eigrp_tlv_len;
 470         tlen-=eigrp_tlv_len;
 471     }
 472     return;
 473 trunc:
 474     ND_PRINT((ndo, "\n\t\t packet exceeded snapshot"));
 475 }