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 #include <config.h>
  26
  27 #include "netdissect-stdinc.h"
  28
  29 #include "netdissect.h"
  30 #include "addrtoname.h"
  31 #include "extract.h"
  32
  33 struct egp_packet {
  34         nd_uint8_t  egp_version;
  35 #define EGP_VERSION     2
  36         nd_uint8_t  egp_type;
  37 #define  EGPT_ACQUIRE   3
  38 #define  EGPT_REACH     5
  39 #define  EGPT_POLL      2
  40 #define  EGPT_UPDATE    1
  41 #define  EGPT_ERROR     8
  42         nd_uint8_t  egp_code;
  43 #define  EGPC_REQUEST   0
  44 #define  EGPC_CONFIRM   1
  45 #define  EGPC_REFUSE    2
  46 #define  EGPC_CEASE     3
  47 #define  EGPC_CEASEACK  4
  48 #define  EGPC_HELLO     0
  49 #define  EGPC_HEARDU    1
  50         nd_uint8_t  egp_status;
  51 #define  EGPS_UNSPEC    0
  52 #define  EGPS_ACTIVE    1
  53 #define  EGPS_PASSIVE   2
  54 #define  EGPS_NORES     3
  55 #define  EGPS_ADMIN     4
  56 #define  EGPS_GODOWN    5
  57 #define  EGPS_PARAM     6
  58 #define  EGPS_PROTO     7
  59 #define  EGPS_INDET     0
  60 #define  EGPS_UP        1
  61 #define  EGPS_DOWN      2
  62 #define  EGPS_UNSOL     0x80
  63         nd_uint16_t  egp_checksum;
  64         nd_uint16_t  egp_as;
  65         nd_uint16_t  egp_sequence;
  66         union {
  67                 nd_uint16_t egpu_hello;
  68                 nd_uint8_t  egpu_gws[2];
  69                 nd_uint16_t egpu_reason;
  70 #define  EGPR_UNSPEC    0
  71 #define  EGPR_BADHEAD   1
  72 #define  EGPR_BADDATA   2
  73 #define  EGPR_NOREACH   3
  74 #define  EGPR_XSPOLL    4
  75 #define  EGPR_NORESP    5
  76 #define  EGPR_UVERSION  6
  77         } egp_handg;
  78 #define  egp_hello  egp_handg.egpu_hello
  79 #define  egp_intgw  egp_handg.egpu_gws[0]
  80 #define  egp_extgw  egp_handg.egpu_gws[1]
  81 #define  egp_reason  egp_handg.egpu_reason
  82         union {
  83                 nd_uint16_t egpu_poll;
  84                 nd_ipv4 egpu_sourcenet;
  85         } egp_pands;
  86 #define  egp_poll  egp_pands.egpu_poll
  87 #define  egp_sourcenet  egp_pands.egpu_sourcenet
  88 };
  89
  90 static const char *egp_acquire_codes[] = {
  91         "request",
  92         "confirm",
  93         "refuse",
  94         "cease",
  95         "cease_ack"
  96 };
  97
  98 static const char *egp_acquire_status[] = {
  99         "unspecified",
 100         "active_mode",
 101         "passive_mode",
 102         "insufficient_resources",
 103         "administratively_prohibited",
 104         "going_down",
 105         "parameter_violation",
 106         "protocol_violation"
 107 };
 108
 109 static const char *egp_reach_codes[] = {
 110         "hello",
 111         "i-h-u"
 112 };
 113
 114 static const char *egp_status_updown[] = {
 115         "indeterminate",
 116         "up",
 117         "down"
 118 };
 119
 120 static const char *egp_reasons[] = {
 121         "unspecified",
 122         "bad_EGP_header_format",
 123         "bad_EGP_data_field_format",
 124         "reachability_info_unavailable",
 125         "excessive_polling_rate",
 126         "no_response",
 127         "unsupported_version"
 128 };
 129
 130 static void
 131 egpnr_print(netdissect_options *ndo,
 132            const struct egp_packet *egp, u_int length)
 133 {
 134         const uint8_t *cp;
 135         uint32_t addr;
 136         uint32_t net;
 137         u_int netlen;
 138         u_int gateways, distances, networks;
 139         u_int intgw, extgw, t_gateways;
 140         const char *comma;
 141
 142         addr = GET_IPV4_TO_NETWORK_ORDER(egp->egp_sourcenet);
 143         if (IN_CLASSA(addr)) {
 144                 net = addr & IN_CLASSA_NET;
 145                 netlen = 1;
 146         } else if (IN_CLASSB(addr)) {
 147                 net = addr & IN_CLASSB_NET;
 148                 netlen = 2;
 149         } else if (IN_CLASSC(addr)) {
 150                 net = addr & IN_CLASSC_NET;
 151                 netlen = 3;
 152         } else {
 153                 net = 0;
 154                 netlen = 0;
 155         }
 156         cp = (const uint8_t *)(egp + 1);
 157         length -= sizeof(*egp);
 158
 159         intgw = GET_U_1(egp->egp_intgw);
 160         extgw = GET_U_1(egp->egp_extgw);
 161         t_gateways = intgw + extgw;
 162         for (gateways = 0; gateways < t_gateways; ++gateways) {
 163                 /* Pickup host part of gateway address */
 164                 addr = 0;
 165                 if (length < 4 - netlen)
 166                         goto trunc;
 167                 ND_TCHECK_LEN(cp, 4 - netlen);
 168                 switch (netlen) {
 169
 170                 case 1:
 171                         addr = GET_U_1(cp);
 172                         cp++;
 173                         /* fall through */
 174                 case 2:
 175                         addr = (addr << 8) | GET_U_1(cp);
 176                         cp++;
 177                         /* fall through */
 178                 case 3:
 179                         addr = (addr << 8) | GET_U_1(cp);
 180                         cp++;
 181                         break;
 182                 }
 183                 addr |= net;
 184                 length -= 4 - netlen;
 185                 if (length < 1)
 186                         goto trunc;
 187                 distances = GET_U_1(cp);
 188                 cp++;
 189                 length--;
 190                 ND_PRINT(" %s %s ",
 191                        gateways < intgw ? "int" : "ext",
 192                        ipaddr_string(ndo, (const u_char *)&addr)); /* local buffer, not packet data; don't use GET_IPADDR_STRING() */
 193
 194                 comma = "";
 195                 ND_PRINT("(");
 196                 while (distances != 0) {
 197                         if (length < 2)
 198                                 goto trunc;
 199                         ND_PRINT("%sd%u:", comma, GET_U_1(cp));
 200                         cp++;
 201                         comma = ", ";
 202                         networks = GET_U_1(cp);
 203                         cp++;
 204                         length -= 2;
 205                         while (networks != 0) {
 206                                 /* Pickup network number */
 207                                 if (length < 1)
 208                                         goto trunc;
 209                                 addr = ((uint32_t) GET_U_1(cp)) << 24;
 210                                 cp++;
 211                                 length--;
 212                                 if (IN_CLASSB(addr)) {
 213                                         if (length < 1)
 214                                                 goto trunc;
 215                                         addr |= ((uint32_t) GET_U_1(cp)) << 16;
 216                                         cp++;
 217                                         length--;
 218                                 } else if (!IN_CLASSA(addr)) {
 219                                         if (length < 2)
 220                                                 goto trunc;
 221                                         addr |= ((uint32_t) GET_U_1(cp)) << 16;
 222                                         cp++;
 223                                         addr |= ((uint32_t) GET_U_1(cp)) << 8;
 224                                         cp++;
 225                                         length -= 2;
 226                                 }
 227                                 ND_PRINT(" %s", ipaddr_string(ndo, (const u_char *)&addr)); /* local buffer, not packet data; don't use GET_IPADDR_STRING() */
 228                                 networks--;
 229                         }
 230                         distances--;
 231                 }
 232                 ND_PRINT(")");
 233         }
 234         return;
 235 trunc:
 236         nd_print_trunc(ndo);
 237 }
 238
 239 void
 240 egp_print(netdissect_options *ndo,
 241           const uint8_t *bp, u_int length)
 242 {
 243         const struct egp_packet *egp;
 244         u_int version;
 245         u_int type;
 246         u_int code;
 247         u_int status;
 248
 249         ndo->ndo_protocol = "egp";
 250         egp = (const struct egp_packet *)bp;
 251         if (length < sizeof(*egp) || !ND_TTEST_SIZE(egp)) {
 252                 nd_print_trunc(ndo);
 253                 return;
 254         }
 255
 256         version = GET_U_1(egp->egp_version);
 257         if (!ndo->ndo_vflag) {
 258             ND_PRINT("EGPv%u, AS %u, seq %u, length %u",
 259                    version,
 260                    GET_BE_U_2(egp->egp_as),
 261                    GET_BE_U_2(egp->egp_sequence),
 262                    length);
 263             return;
 264         } else
 265             ND_PRINT("EGPv%u, length %u",
 266                    version,
 267                    length);
 268
 269         if (version != EGP_VERSION) {
 270                 ND_PRINT("[version %u]", version);
 271                 return;
 272         }
 273
 274         type = GET_U_1(egp->egp_type);
 275         code = GET_U_1(egp->egp_code);
 276         status = GET_U_1(egp->egp_status);
 277
 278         switch (type) {
 279         case EGPT_ACQUIRE:
 280                 ND_PRINT(" acquire");
 281                 switch (code) {
 282                 case EGPC_REQUEST:
 283                 case EGPC_CONFIRM:
 284                         ND_PRINT(" %s", egp_acquire_codes[code]);
 285                         switch (status) {
 286                         case EGPS_UNSPEC:
 287                         case EGPS_ACTIVE:
 288                         case EGPS_PASSIVE:
 289                                 ND_PRINT(" %s", egp_acquire_status[status]);
 290                                 break;
 291
 292                         default:
 293                                 ND_PRINT(" [status %u]", status);
 294                                 break;
 295                         }
 296                         ND_PRINT(" hello:%u poll:%u",
 297                                GET_BE_U_2(egp->egp_hello),
 298                                GET_BE_U_2(egp->egp_poll));
 299                         break;
 300
 301                 case EGPC_REFUSE:
 302                 case EGPC_CEASE:
 303                 case EGPC_CEASEACK:
 304                         ND_PRINT(" %s", egp_acquire_codes[code]);
 305                         switch (status ) {
 306                         case EGPS_UNSPEC:
 307                         case EGPS_NORES:
 308                         case EGPS_ADMIN:
 309                         case EGPS_GODOWN:
 310                         case EGPS_PARAM:
 311                         case EGPS_PROTO:
 312                                 ND_PRINT(" %s", egp_acquire_status[status]);
 313                                 break;
 314
 315                         default:
 316                                 ND_PRINT("[status %u]", status);
 317                                 break;
 318                         }
 319                         break;
 320
 321                 default:
 322                         ND_PRINT("[code %u]", code);
 323                         break;
 324                 }
 325                 break;
 326
 327         case EGPT_REACH:
 328                 switch (code) {
 329
 330                 case EGPC_HELLO:
 331                 case EGPC_HEARDU:
 332                         ND_PRINT(" %s", egp_reach_codes[code]);
 333                         if (status <= EGPS_DOWN)
 334                                 ND_PRINT(" state:%s", egp_status_updown[status]);
 335                         else
 336                                 ND_PRINT(" [status %u]", status);
 337                         break;
 338
 339                 default:
 340                         ND_PRINT("[reach code %u]", code);
 341                         break;
 342                 }
 343                 break;
 344
 345         case EGPT_POLL:
 346                 ND_PRINT(" poll");
 347                 if (status <= EGPS_DOWN)
 348                         ND_PRINT(" state:%s", egp_status_updown[status]);
 349                 else
 350                         ND_PRINT(" [status %u]", status);
 351                 ND_PRINT(" net:%s", GET_IPADDR_STRING(egp->egp_sourcenet));
 352                 break;
 353
 354         case EGPT_UPDATE:
 355                 ND_PRINT(" update");
 356                 if (status & EGPS_UNSOL) {
 357                         status &= ~EGPS_UNSOL;
 358                         ND_PRINT(" unsolicited");
 359                 }
 360                 if (status <= EGPS_DOWN)
 361                         ND_PRINT(" state:%s", egp_status_updown[status]);
 362                 else
 363                         ND_PRINT(" [status %u]", status);
 364                 ND_PRINT(" %s int %u ext %u",
 365                        GET_IPADDR_STRING(egp->egp_sourcenet),
 366                        GET_U_1(egp->egp_intgw),
 367                        GET_U_1(egp->egp_extgw));
 368                 if (ndo->ndo_vflag)
 369                         egpnr_print(ndo, egp, length);
 370                 break;
 371
 372         case EGPT_ERROR:
 373                 ND_PRINT(" error");
 374                 if (status <= EGPS_DOWN)
 375                         ND_PRINT(" state:%s", egp_status_updown[status]);
 376                 else
 377                         ND_PRINT(" [status %u]", status);
 378
 379                 if (GET_BE_U_2(egp->egp_reason) <= EGPR_UVERSION)
 380                         ND_PRINT(" %s",
 381                                  egp_reasons[GET_BE_U_2(egp->egp_reason)]);
 382                 else
 383                         ND_PRINT(" [reason %u]", GET_BE_U_2(egp->egp_reason));
 384                 break;
 385
 386         default:
 387                 ND_PRINT("[type %u]", type);
 388                 break;
 389         }
 390 }