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 <string.h>
  30
  31 #include "netdissect-stdinc.h"
  32
  33 #include "netdissect.h"
  34 #include "addrtoname.h"
  35 #include "extract.h"
  36
  37 struct egp_packet {
  38         nd_uint8_t  egp_version;
  39 #define EGP_VERSION     2
  40         nd_uint8_t  egp_type;
  41 #define  EGPT_ACQUIRE   3
  42 #define  EGPT_REACH     5
  43 #define  EGPT_POLL      2
  44 #define  EGPT_UPDATE    1
  45 #define  EGPT_ERROR     8
  46         nd_uint8_t  egp_code;
  47 #define  EGPC_REQUEST   0
  48 #define  EGPC_CONFIRM   1
  49 #define  EGPC_REFUSE    2
  50 #define  EGPC_CEASE     3
  51 #define  EGPC_CEASEACK  4
  52 #define  EGPC_HELLO     0
  53 #define  EGPC_HEARDU    1
  54         nd_uint8_t  egp_status;
  55 #define  EGPS_UNSPEC    0
  56 #define  EGPS_ACTIVE    1
  57 #define  EGPS_PASSIVE   2
  58 #define  EGPS_NORES     3
  59 #define  EGPS_ADMIN     4
  60 #define  EGPS_GODOWN    5
  61 #define  EGPS_PARAM     6
  62 #define  EGPS_PROTO     7
  63 #define  EGPS_INDET     0
  64 #define  EGPS_UP        1
  65 #define  EGPS_DOWN      2
  66 #define  EGPS_UNSOL     0x80
  67         nd_uint16_t  egp_checksum;
  68         nd_uint16_t  egp_as;
  69         nd_uint16_t  egp_sequence;
  70         union {
  71                 nd_uint16_t egpu_hello;
  72                 nd_uint8_t  egpu_gws[2];
  73                 nd_uint16_t egpu_reason;
  74 #define  EGPR_UNSPEC    0
  75 #define  EGPR_BADHEAD   1
  76 #define  EGPR_BADDATA   2
  77 #define  EGPR_NOREACH   3
  78 #define  EGPR_XSPOLL    4
  79 #define  EGPR_NORESP    5
  80 #define  EGPR_UVERSION  6
  81         } egp_handg;
  82 #define  egp_hello  egp_handg.egpu_hello
  83 #define  egp_intgw  egp_handg.egpu_gws[0]
  84 #define  egp_extgw  egp_handg.egpu_gws[1]
  85 #define  egp_reason  egp_handg.egpu_reason
  86         union {
  87                 nd_uint16_t egpu_poll;
  88                 nd_ipv4 egpu_sourcenet;
  89         } egp_pands;
  90 #define  egp_poll  egp_pands.egpu_poll
  91 #define  egp_sourcenet  egp_pands.egpu_sourcenet
  92 };
  93
  94 static const char *egp_acquire_codes[] = {
  95         "request",
  96         "confirm",
  97         "refuse",
  98         "cease",
  99         "cease_ack"
 100 };
 101
 102 static const char *egp_acquire_status[] = {
 103         "unspecified",
 104         "active_mode",
 105         "passive_mode",
 106         "insufficient_resources",
 107         "administratively_prohibited",
 108         "going_down",
 109         "parameter_violation",
 110         "protocol_violation"
 111 };
 112
 113 static const char *egp_reach_codes[] = {
 114         "hello",
 115         "i-h-u"
 116 };
 117
 118 static const char *egp_status_updown[] = {
 119         "indeterminate",
 120         "up",
 121         "down"
 122 };
 123
 124 static const char *egp_reasons[] = {
 125         "unspecified",
 126         "bad_EGP_header_format",
 127         "bad_EGP_data_field_format",
 128         "reachability_info_unavailable",
 129         "excessive_polling_rate",
 130         "no_response",
 131         "unsupported_version"
 132 };
 133
 134 static void
 135 egpnrprint(netdissect_options *ndo,
 136            const struct egp_packet *egp, u_int length)
 137 {
 138         const uint8_t *cp;
 139         uint32_t addr;
 140         uint32_t net;
 141         u_int netlen;
 142         u_int gateways, distances, networks;
 143         u_int intgw, extgw, t_gateways;
 144         const char *comma;
 145
 146         addr = EXTRACT_IPV4_TO_NETWORK_ORDER(egp->egp_sourcenet);
 147         if (IN_CLASSA(addr)) {
 148                 net = addr & IN_CLASSA_NET;
 149                 netlen = 1;
 150         } else if (IN_CLASSB(addr)) {
 151                 net = addr & IN_CLASSB_NET;
 152                 netlen = 2;
 153         } else if (IN_CLASSC(addr)) {
 154                 net = addr & IN_CLASSC_NET;
 155                 netlen = 3;
 156         } else {
 157                 net = 0;
 158                 netlen = 0;
 159         }
 160         cp = (const uint8_t *)(egp + 1);
 161         length -= sizeof(*egp);
 162
 163         intgw = EXTRACT_U_1(egp->egp_intgw);
 164         extgw = EXTRACT_U_1(egp->egp_extgw);
 165         t_gateways = intgw + extgw;
 166         for (gateways = 0; gateways < t_gateways; ++gateways) {
 167                 /* Pickup host part of gateway address */
 168                 addr = 0;
 169                 if (length < 4 - netlen)
 170                         goto trunc;
 171                 ND_TCHECK_LEN(cp, 4 - netlen);
 172                 switch (netlen) {
 173
 174                 case 1:
 175                         addr = EXTRACT_U_1(cp);
 176                         cp++;
 177                         /* fall through */
 178                 case 2:
 179                         addr = (addr << 8) | EXTRACT_U_1(cp);
 180                         cp++;
 181                         /* fall through */
 182                 case 3:
 183                         addr = (addr << 8) | EXTRACT_U_1(cp);
 184                         cp++;
 185                         break;
 186                 }
 187                 addr |= net;
 188                 length -= 4 - netlen;
 189                 if (length < 1)
 190                         goto trunc;
 191                 ND_TCHECK_1(cp);
 192                 distances = EXTRACT_U_1(cp);
 193                 cp++;
 194                 length--;
 195                 ND_PRINT(" %s %s ",
 196                        gateways < intgw ? "int" : "ext",
 197                        ipaddr_string(ndo, &addr));
 198
 199                 comma = "";
 200                 ND_PRINT("(");
 201                 while (distances != 0) {
 202                         if (length < 2)
 203                                 goto trunc;
 204                         ND_TCHECK_2(cp);
 205                         ND_PRINT("%sd%u:", comma, EXTRACT_U_1(cp));
 206                         cp++;
 207                         comma = ", ";
 208                         networks = EXTRACT_U_1(cp);
 209                         cp++;
 210                         length -= 2;
 211                         while (networks != 0) {
 212                                 /* Pickup network number */
 213                                 if (length < 1)
 214                                         goto trunc;
 215                                 ND_TCHECK_1(cp);
 216                                 addr = ((uint32_t) EXTRACT_U_1(cp)) << 24;
 217                                 cp++;
 218                                 length--;
 219                                 if (IN_CLASSB(addr)) {
 220                                         if (length < 1)
 221                                                 goto trunc;
 222                                         ND_TCHECK_1(cp);
 223                                         addr |= ((uint32_t) EXTRACT_U_1(cp)) << 16;
 224                                         cp++;
 225                                         length--;
 226                                 } else if (!IN_CLASSA(addr)) {
 227                                         if (length < 2)
 228                                                 goto trunc;
 229                                         ND_TCHECK_2(cp);
 230                                         addr |= ((uint32_t) EXTRACT_U_1(cp)) << 16;
 231                                         cp++;
 232                                         addr |= ((uint32_t) EXTRACT_U_1(cp)) << 8;
 233                                         cp++;
 234                                         length -= 2;
 235                                 }
 236                                 ND_PRINT(" %s", ipaddr_string(ndo, &addr));
 237                                 networks--;
 238                         }
 239                         distances--;
 240                 }
 241                 ND_PRINT(")");
 242         }
 243         return;
 244 trunc:
 245         ND_PRINT("[|]");
 246 }
 247
 248 void
 249 egp_print(netdissect_options *ndo,
 250           const uint8_t *bp, u_int length)
 251 {
 252         const struct egp_packet *egp;
 253         u_int version;
 254         u_int type;
 255         u_int code;
 256         u_int status;
 257
 258         egp = (const struct egp_packet *)bp;
 259         if (length < sizeof(*egp) || !ND_TTEST_SIZE(egp)) {
 260                 ND_PRINT("[|egp]");
 261                 return;
 262         }
 263
 264         version = EXTRACT_U_1(egp->egp_version);
 265         if (!ndo->ndo_vflag) {
 266             ND_PRINT("EGPv%u, AS %u, seq %u, length %u",
 267                    version,
 268                    EXTRACT_BE_U_2(egp->egp_as),
 269                    EXTRACT_BE_U_2(egp->egp_sequence),
 270                    length);
 271             return;
 272         } else
 273             ND_PRINT("EGPv%u, length %u",
 274                    version,
 275                    length);
 276
 277         if (version != EGP_VERSION) {
 278                 ND_PRINT("[version %u]", version);
 279                 return;
 280         }
 281
 282         type = EXTRACT_U_1(egp->egp_type);
 283         code = EXTRACT_U_1(egp->egp_code);
 284         status = EXTRACT_U_1(egp->egp_status);
 285
 286         switch (type) {
 287         case EGPT_ACQUIRE:
 288                 ND_PRINT(" acquire");
 289                 switch (code) {
 290                 case EGPC_REQUEST:
 291                 case EGPC_CONFIRM:
 292                         ND_PRINT(" %s", egp_acquire_codes[code]);
 293                         switch (status) {
 294                         case EGPS_UNSPEC:
 295                         case EGPS_ACTIVE:
 296                         case EGPS_PASSIVE:
 297                                 ND_PRINT(" %s", egp_acquire_status[status]);
 298                                 break;
 299
 300                         default:
 301                                 ND_PRINT(" [status %u]", status);
 302                                 break;
 303                         }
 304                         ND_PRINT(" hello:%u poll:%u",
 305                                EXTRACT_BE_U_2(egp->egp_hello),
 306                                EXTRACT_BE_U_2(egp->egp_poll));
 307                         break;
 308
 309                 case EGPC_REFUSE:
 310                 case EGPC_CEASE:
 311                 case EGPC_CEASEACK:
 312                         ND_PRINT(" %s", egp_acquire_codes[code]);
 313                         switch (status ) {
 314                         case EGPS_UNSPEC:
 315                         case EGPS_NORES:
 316                         case EGPS_ADMIN:
 317                         case EGPS_GODOWN:
 318                         case EGPS_PARAM:
 319                         case EGPS_PROTO:
 320                                 ND_PRINT(" %s", egp_acquire_status[status]);
 321                                 break;
 322
 323                         default:
 324                                 ND_PRINT("[status %u]", status);
 325                                 break;
 326                         }
 327                         break;
 328
 329                 default:
 330                         ND_PRINT("[code %u]", code);
 331                         break;
 332                 }
 333                 break;
 334
 335         case EGPT_REACH:
 336                 switch (code) {
 337
 338                 case EGPC_HELLO:
 339                 case EGPC_HEARDU:
 340                         ND_PRINT(" %s", egp_reach_codes[code]);
 341                         if (status <= EGPS_DOWN)
 342                                 ND_PRINT(" state:%s", egp_status_updown[status]);
 343                         else
 344                                 ND_PRINT(" [status %u]", status);
 345                         break;
 346
 347                 default:
 348                         ND_PRINT("[reach code %u]", code);
 349                         break;
 350                 }
 351                 break;
 352
 353         case EGPT_POLL:
 354                 ND_PRINT(" poll");
 355                 if (status <= EGPS_DOWN)
 356                         ND_PRINT(" state:%s", egp_status_updown[status]);
 357                 else
 358                         ND_PRINT(" [status %u]", status);
 359                 ND_PRINT(" net:%s", ipaddr_string(ndo, &egp->egp_sourcenet));
 360                 break;
 361
 362         case EGPT_UPDATE:
 363                 ND_PRINT(" update");
 364                 if (status & EGPS_UNSOL) {
 365                         status &= ~EGPS_UNSOL;
 366                         ND_PRINT(" unsolicited");
 367                 }
 368                 if (status <= EGPS_DOWN)
 369                         ND_PRINT(" state:%s", egp_status_updown[status]);
 370                 else
 371                         ND_PRINT(" [status %u]", status);
 372                 ND_PRINT(" %s int %u ext %u",
 373                        ipaddr_string(ndo, &egp->egp_sourcenet),
 374                        EXTRACT_U_1(egp->egp_intgw),
 375                        EXTRACT_U_1(egp->egp_extgw));
 376                 if (ndo->ndo_vflag)
 377                         egpnrprint(ndo, egp, length);
 378                 break;
 379
 380         case EGPT_ERROR:
 381                 ND_PRINT(" error");
 382                 if (status <= EGPS_DOWN)
 383                         ND_PRINT(" state:%s", egp_status_updown[status]);
 384                 else
 385                         ND_PRINT(" [status %u]", status);
 386
 387                 if (EXTRACT_BE_U_2(egp->egp_reason) <= EGPR_UVERSION)
 388                         ND_PRINT(" %s", egp_reasons[EXTRACT_BE_U_2(egp->egp_reason)]);
 389                 else
 390                         ND_PRINT(" [reason %u]", EXTRACT_BE_U_2(egp->egp_reason));
 391                 break;
 392
 393         default:
 394                 ND_PRINT("[type %u]", type);
 395                 break;
 396         }
 397 }