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

   1 /*
   2  * Copyright (c) 1991, 1992, 1993, 1994, 1995, 1996
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms are permitted
   6  * provided that the above copyright notice and this paragraph are
   7  * duplicated in all such forms and that any documentation,
   8  * advertising materials, and other materials related to such
   9  * distribution and use acknowledge that the software was developed
  10  * by the University of California, Lawrence Berkeley Laboratory,
  11  * Berkeley, CA.  The name of the University may not be used to
  12  * endorse or promote products derived from this software without
  13  * specific prior written permission.
  14  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  16  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  17  *
  18  * Initial contribution from Jeff Honig (jch@MITCHELL.CIT.CORNELL.EDU).
  19  */
  20
  21 /* \summary: Exterior Gateway Protocol (EGP) printer */
  22
  23 /* specification: RFC 827 */
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include <config.h>
  27 #endif
  28
  29 #include "netdissect-stdinc.h"
  30
  31 #define ND_LONGJMP_FROM_TCHECK
  32 #include "netdissect.h"
  33 #include "addrtoname.h"
  34 #include "extract.h"
  35
  36 struct egp_packet {
  37         nd_uint8_t  egp_version;
  38 #define EGP_VERSION     2
  39         nd_uint8_t  egp_type;
  40 #define  EGPT_ACQUIRE   3
  41 #define  EGPT_REACH     5
  42 #define  EGPT_POLL      2
  43 #define  EGPT_UPDATE    1
  44 #define  EGPT_ERROR     8
  45         nd_uint8_t  egp_code;
  46 #define  EGPC_REQUEST   0
  47 #define  EGPC_CONFIRM   1
  48 #define  EGPC_REFUSE    2
  49 #define  EGPC_CEASE     3
  50 #define  EGPC_CEASEACK  4
  51 #define  EGPC_HELLO     0
  52 #define  EGPC_HEARDU    1
  53         nd_uint8_t  egp_status;
  54 #define  EGPS_UNSPEC    0
  55 #define  EGPS_ACTIVE    1
  56 #define  EGPS_PASSIVE   2
  57 #define  EGPS_NORES     3
  58 #define  EGPS_ADMIN     4
  59 #define  EGPS_GODOWN    5
  60 #define  EGPS_PARAM     6
  61 #define  EGPS_PROTO     7
  62 #define  EGPS_INDET     0
  63 #define  EGPS_UP        1
  64 #define  EGPS_DOWN      2
  65 #define  EGPS_UNSOL     0x80
  66         nd_uint16_t  egp_checksum;
  67         nd_uint16_t  egp_as;
  68         nd_uint16_t  egp_sequence;
  69         union {
  70                 nd_uint16_t egpu_hello;
  71                 nd_uint8_t  egpu_gws[2];
  72                 nd_uint16_t egpu_reason;
  73 #define  EGPR_UNSPEC    0
  74 #define  EGPR_BADHEAD   1
  75 #define  EGPR_BADDATA   2
  76 #define  EGPR_NOREACH   3
  77 #define  EGPR_XSPOLL    4
  78 #define  EGPR_NORESP    5
  79 #define  EGPR_UVERSION  6
  80         } egp_handg;
  81 #define  egp_hello  egp_handg.egpu_hello
  82 #define  egp_intgw  egp_handg.egpu_gws[0]
  83 #define  egp_extgw  egp_handg.egpu_gws[1]
  84 #define  egp_reason  egp_handg.egpu_reason
  85         union {
  86                 nd_uint16_t egpu_poll;
  87                 nd_ipv4 egpu_sourcenet;
  88         } egp_pands;
  89 #define  egp_poll  egp_pands.egpu_poll
  90 #define  egp_sourcenet  egp_pands.egpu_sourcenet
  91 };
  92
  93 static const struct tok egp_type_str[] = {
  94         { EGPT_ACQUIRE, "acquire" },
  95         { EGPT_REACH,   "reach"   },
  96         { EGPT_POLL,    "poll"    },
  97         { EGPT_UPDATE,  "update"  },
  98         { EGPT_ERROR,   "error"   },
  99         { 0, NULL }
 100 };
 101
 102 static const struct tok egp_acquire_codes_str[] = {
 103         { EGPC_REQUEST,  "request"   },
 104         { EGPC_CONFIRM,  "confirm"   },
 105         { EGPC_REFUSE,   "refuse"    },
 106         { EGPC_CEASE,    "cease"     },
 107         { EGPC_CEASEACK, "cease_ack" },
 108         { 0, NULL }
 109 };
 110
 111 static const struct tok egp_acquire_status_str[] = {
 112         { EGPS_UNSPEC,  "unspecified"                 },
 113         { EGPS_ACTIVE,  "active_mode"                 },
 114         { EGPS_PASSIVE, "passive_mode"                },
 115         { EGPS_NORES,   "insufficient_resources"      },
 116         { EGPS_ADMIN,   "administratively_prohibited" },
 117         { EGPS_GODOWN,  "going_down"                  },
 118         { EGPS_PARAM,   "parameter_violation"         },
 119         { EGPS_PROTO,   "protocol_violation"          },
 120         { 0, NULL }
 121 };
 122
 123 static const struct tok egp_reach_codes_str[] = {
 124         { EGPC_HELLO,  "hello" },
 125         { EGPC_HEARDU, "i-h-u" },
 126         { 0, NULL }
 127 };
 128
 129 static const struct tok egp_status_updown_str[] = {
 130         { EGPS_INDET, "indeterminate" },
 131         { EGPS_UP,    "up"            },
 132         { EGPS_DOWN,  "down"          },
 133         { 0, NULL }
 134 };
 135
 136 static const struct tok egp_reasons_str[] = {
 137         { EGPR_UNSPEC,   "unspecified"                   },
 138         { EGPR_BADHEAD,  "bad_EGP_header_format"         },
 139         { EGPR_BADDATA,  "bad_EGP_data_field_format"     },
 140         { EGPR_NOREACH,  "reachability_info_unavailable" },
 141         { EGPR_XSPOLL,   "excessive_polling_rate"        },
 142         { EGPR_NORESP,   "no_response"                   },
 143         { EGPR_UVERSION, "unsupported_version"           },
 144         { 0, NULL }
 145 };
 146
 147 static void
 148 egpnr_print(netdissect_options *ndo,
 149            const struct egp_packet *egp, u_int length)
 150 {
 151         const uint8_t *cp;
 152         uint32_t addr;
 153         uint32_t net;
 154         u_int netlen;
 155         u_int gateways, distances, networks;
 156         u_int intgw, extgw, t_gateways;
 157         const char *comma;
 158
 159         addr = GET_IPV4_TO_NETWORK_ORDER(egp->egp_sourcenet);
 160         if (IN_CLASSA(addr)) {
 161                 net = addr & IN_CLASSA_NET;
 162                 netlen = 1;
 163         } else if (IN_CLASSB(addr)) {
 164                 net = addr & IN_CLASSB_NET;
 165                 netlen = 2;
 166         } else if (IN_CLASSC(addr)) {
 167                 net = addr & IN_CLASSC_NET;
 168                 netlen = 3;
 169         } else {
 170                 net = 0;
 171                 netlen = 0;
 172         }
 173         cp = (const uint8_t *)(egp + 1);
 174         length -= sizeof(*egp);
 175
 176         intgw = GET_U_1(egp->egp_intgw);
 177         extgw = GET_U_1(egp->egp_extgw);
 178         t_gateways = intgw + extgw;
 179         for (gateways = 0; gateways < t_gateways; ++gateways) {
 180                 /* Pickup host part of gateway address */
 181                 addr = 0;
 182                 if (length < 4 - netlen)
 183                         goto invalid;
 184                 ND_TCHECK_LEN(cp, 4 - netlen);
 185                 switch (netlen) {
 186
 187                 case 1:
 188                         addr = GET_U_1(cp);
 189                         cp++;
 190                         /* fall through */
 191                 case 2:
 192                         addr = (addr << 8) | GET_U_1(cp);
 193                         cp++;
 194                         /* fall through */
 195                 case 3:
 196                         addr = (addr << 8) | GET_U_1(cp);
 197                         cp++;
 198                         break;
 199                 }
 200                 addr |= net;
 201                 length -= 4 - netlen;
 202                 if (length < 1)
 203                         goto invalid;
 204                 distances = GET_U_1(cp);
 205                 cp++;
 206                 length--;
 207                 ND_PRINT(" %s %s ",
 208                        gateways < intgw ? "int" : "ext",
 209                        ipaddr_string(ndo, (const u_char *)&addr)); /* local buffer, not packet data; don't use GET_IPADDR_STRING() */
 210
 211                 comma = "";
 212                 ND_PRINT("(");
 213                 while (distances != 0) {
 214                         if (length < 2)
 215                                 goto invalid;
 216                         ND_PRINT("%sd%u:", comma, GET_U_1(cp));
 217                         cp++;
 218                         comma = ", ";
 219                         networks = GET_U_1(cp);
 220                         cp++;
 221                         length -= 2;
 222                         while (networks != 0) {
 223                                 /* Pickup network number */
 224                                 if (length < 1)
 225                                         goto invalid;
 226                                 addr = ((uint32_t) GET_U_1(cp)) << 24;
 227                                 cp++;
 228                                 length--;
 229                                 if (IN_CLASSB(addr)) {
 230                                         if (length < 1)
 231                                                 goto invalid;
 232                                         addr |= ((uint32_t) GET_U_1(cp)) << 16;
 233                                         cp++;
 234                                         length--;
 235                                 } else if (!IN_CLASSA(addr)) {
 236                                         if (length < 2)
 237                                                 goto invalid;
 238                                         addr |= ((uint32_t) GET_U_1(cp)) << 16;
 239                                         cp++;
 240                                         addr |= ((uint32_t) GET_U_1(cp)) << 8;
 241                                         cp++;
 242                                         length -= 2;
 243                                 }
 244                                 ND_PRINT(" %s", ipaddr_string(ndo, (const u_char *)&addr)); /* local buffer, not packet data; don't use GET_IPADDR_STRING() */
 245                                 networks--;
 246                         }
 247                         distances--;
 248                 }
 249                 ND_PRINT(")");
 250         }
 251         return;
 252 invalid:
 253         nd_print_invalid(ndo);
 254 }
 255
 256 void
 257 egp_print(netdissect_options *ndo,
 258           const uint8_t *bp, u_int length)
 259 {
 260         const struct egp_packet *egp;
 261         u_int version;
 262         u_int type;
 263         u_int code;
 264         u_int status;
 265
 266         ndo->ndo_protocol = "egp";
 267         egp = (const struct egp_packet *)bp;
 268         ND_ICHECKMSG_ZU("packet length", length, <, sizeof(*egp));
 269         ND_TCHECK_SIZE(egp);
 270
 271         version = GET_U_1(egp->egp_version);
 272         if (!ndo->ndo_vflag) {
 273             ND_PRINT("EGPv%u, AS %u, seq %u, length %u",
 274                    version,
 275                    GET_BE_U_2(egp->egp_as),
 276                    GET_BE_U_2(egp->egp_sequence),
 277                    length);
 278             return;
 279         } else
 280             ND_PRINT("EGPv%u, length %u",
 281                    version,
 282                    length);
 283
 284         if (version != EGP_VERSION) {
 285                 ND_PRINT("[version %u]", version);
 286                 return;
 287         }
 288
 289         type = GET_U_1(egp->egp_type);
 290         ND_PRINT(" %s", tok2str(egp_type_str, "[type %u]", type));
 291         code = GET_U_1(egp->egp_code);
 292         status = GET_U_1(egp->egp_status);
 293
 294         switch (type) {
 295         case EGPT_ACQUIRE:
 296                 ND_PRINT(" %s", tok2str(egp_acquire_codes_str, "[code %u]", code));
 297                 switch (code) {
 298                 case EGPC_REQUEST:
 299                 case EGPC_CONFIRM:
 300                         switch (status) {
 301                         case EGPS_UNSPEC:
 302                         case EGPS_ACTIVE:
 303                         case EGPS_PASSIVE:
 304                                 ND_PRINT(" %s", tok2str(egp_acquire_status_str, "%u", status));
 305                                 break;
 306
 307                         default:
 308                                 ND_PRINT(" [status %u]", status);
 309                                 break;
 310                         }
 311                         ND_PRINT(" hello:%u poll:%u",
 312                                GET_BE_U_2(egp->egp_hello),
 313                                GET_BE_U_2(egp->egp_poll));
 314                         break;
 315
 316                 case EGPC_REFUSE:
 317                 case EGPC_CEASE:
 318                 case EGPC_CEASEACK:
 319                         switch (status ) {
 320                         case EGPS_UNSPEC:
 321                         case EGPS_NORES:
 322                         case EGPS_ADMIN:
 323                         case EGPS_GODOWN:
 324                         case EGPS_PARAM:
 325                         case EGPS_PROTO:
 326                                 ND_PRINT(" %s", tok2str(egp_acquire_status_str, "%u", status));
 327                                 break;
 328
 329                         default:
 330                                 ND_PRINT("[status %u]", status);
 331                                 break;
 332                         }
 333                         break;
 334                 }
 335                 break;
 336
 337         case EGPT_REACH:
 338                 ND_PRINT(" %s", tok2str(egp_reach_codes_str, "[reach code %u]", code));
 339                 switch (code) {
 340                 case EGPC_HELLO:
 341                 case EGPC_HEARDU:
 342                         ND_PRINT(" state:%s", tok2str(egp_status_updown_str, "%u", status));
 343                         break;
 344                 }
 345                 break;
 346
 347         case EGPT_POLL:
 348                 ND_PRINT(" state:%s", tok2str(egp_status_updown_str, "%u", status));
 349                 ND_PRINT(" net:%s", GET_IPADDR_STRING(egp->egp_sourcenet));
 350                 break;
 351
 352         case EGPT_UPDATE:
 353                 if (status & EGPS_UNSOL) {
 354                         status &= ~EGPS_UNSOL;
 355                         ND_PRINT(" unsolicited");
 356                 }
 357                 ND_PRINT(" state:%s", tok2str(egp_status_updown_str, "%u", status));
 358                 ND_PRINT(" %s int %u ext %u",
 359                        GET_IPADDR_STRING(egp->egp_sourcenet),
 360                        GET_U_1(egp->egp_intgw),
 361                        GET_U_1(egp->egp_extgw));
 362                 if (ndo->ndo_vflag)
 363                         egpnr_print(ndo, egp, length);
 364                 break;
 365
 366         case EGPT_ERROR:
 367                 ND_PRINT(" state:%s", tok2str(egp_status_updown_str, "%u", status));
 368                 ND_PRINT(" %s", tok2str(egp_reasons_str, "[reason %u]", GET_BE_U_2(egp->egp_reason)));
 369                 break;
 370         }
 371         return;
 372 invalid:
 373         nd_print_invalid(ndo);
 374 }