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