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      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 (at) MITCHELL.CIT.CORNELL.EDU).
     19  */
     20 
     21 #include <sys/cdefs.h>
     22 #ifndef lint
     23 __RCSID("$NetBSD: print-egp.c,v 1.9 2026/03/19 00:05:13 christos Exp $");
     24 #endif
     25 
     26 /* \summary: Exterior Gateway Protocol (EGP) printer */
     27 
     28 /* specification: RFC 827 */
     29 
     30 #include <config.h>
     31 
     32 #include "netdissect-stdinc.h"
     33 
     34 #define ND_LONGJMP_FROM_TCHECK
     35 #include "netdissect.h"
     36 #include "addrtoname.h"
     37 #include "extract.h"
     38 
     39 struct egp_packet {
     40 	nd_uint8_t  egp_version;
     41 #define	EGP_VERSION	2
     42 	nd_uint8_t  egp_type;
     43 #define  EGPT_ACQUIRE	3
     44 #define  EGPT_REACH	5
     45 #define  EGPT_POLL	2
     46 #define  EGPT_UPDATE	1
     47 #define  EGPT_ERROR	8
     48 	nd_uint8_t  egp_code;
     49 #define  EGPC_REQUEST	0
     50 #define  EGPC_CONFIRM	1
     51 #define  EGPC_REFUSE	2
     52 #define  EGPC_CEASE	3
     53 #define  EGPC_CEASEACK	4
     54 #define  EGPC_HELLO	0
     55 #define  EGPC_HEARDU	1
     56 	nd_uint8_t  egp_status;
     57 #define  EGPS_UNSPEC	0
     58 #define  EGPS_ACTIVE	1
     59 #define  EGPS_PASSIVE	2
     60 #define  EGPS_NORES	3
     61 #define  EGPS_ADMIN	4
     62 #define  EGPS_GODOWN	5
     63 #define  EGPS_PARAM	6
     64 #define  EGPS_PROTO	7
     65 #define  EGPS_INDET	0
     66 #define  EGPS_UP	1
     67 #define  EGPS_DOWN	2
     68 #define  EGPS_UNSOL	0x80
     69 	nd_uint16_t  egp_checksum;
     70 	nd_uint16_t  egp_as;
     71 	nd_uint16_t  egp_sequence;
     72 	union {
     73 		nd_uint16_t egpu_hello;
     74 		nd_uint8_t  egpu_gws[2];
     75 		nd_uint16_t egpu_reason;
     76 #define  EGPR_UNSPEC	0
     77 #define  EGPR_BADHEAD	1
     78 #define  EGPR_BADDATA	2
     79 #define  EGPR_NOREACH	3
     80 #define  EGPR_XSPOLL	4
     81 #define  EGPR_NORESP	5
     82 #define  EGPR_UVERSION	6
     83 	} egp_handg;
     84 #define  egp_hello  egp_handg.egpu_hello
     85 #define  egp_intgw  egp_handg.egpu_gws[0]
     86 #define  egp_extgw  egp_handg.egpu_gws[1]
     87 #define  egp_reason  egp_handg.egpu_reason
     88 	union {
     89 		nd_uint16_t egpu_poll;
     90 		nd_ipv4 egpu_sourcenet;
     91 	} egp_pands;
     92 #define  egp_poll  egp_pands.egpu_poll
     93 #define  egp_sourcenet  egp_pands.egpu_sourcenet
     94 };
     95 
     96 static const struct tok egp_type_str[] = {
     97 	{ EGPT_ACQUIRE, "acquire" },
     98 	{ EGPT_REACH,   "reach"   },
     99 	{ EGPT_POLL,    "poll"    },
    100 	{ EGPT_UPDATE,  "update"  },
    101 	{ EGPT_ERROR,   "error"   },
    102 	{ 0, NULL }
    103 };
    104 
    105 static const struct tok egp_acquire_codes_str[] = {
    106 	{ EGPC_REQUEST,  "request"   },
    107 	{ EGPC_CONFIRM,  "confirm"   },
    108 	{ EGPC_REFUSE,   "refuse"    },
    109 	{ EGPC_CEASE,    "cease"     },
    110 	{ EGPC_CEASEACK, "cease_ack" },
    111 	{ 0, NULL }
    112 };
    113 
    114 static const struct tok egp_acquire_status_str[] = {
    115 	{ EGPS_UNSPEC,  "unspecified"                 },
    116 	{ EGPS_ACTIVE,  "active_mode"                 },
    117 	{ EGPS_PASSIVE, "passive_mode"                },
    118 	{ EGPS_NORES,   "insufficient_resources"      },
    119 	{ EGPS_ADMIN,   "administratively_prohibited" },
    120 	{ EGPS_GODOWN,  "going_down"                  },
    121 	{ EGPS_PARAM,   "parameter_violation"         },
    122 	{ EGPS_PROTO,   "protocol_violation"          },
    123 	{ 0, NULL }
    124 };
    125 
    126 static const struct tok egp_reach_codes_str[] = {
    127 	{ EGPC_HELLO,  "hello" },
    128 	{ EGPC_HEARDU, "i-h-u" },
    129 	{ 0, NULL }
    130 };
    131 
    132 static const struct tok egp_status_updown_str[] = {
    133 	{ EGPS_INDET, "indeterminate" },
    134 	{ EGPS_UP,    "up"            },
    135 	{ EGPS_DOWN,  "down"          },
    136 	{ 0, NULL }
    137 };
    138 
    139 static const struct tok egp_reasons_str[] = {
    140 	{ EGPR_UNSPEC,   "unspecified"                   },
    141 	{ EGPR_BADHEAD,  "bad_EGP_header_format"         },
    142 	{ EGPR_BADDATA,  "bad_EGP_data_field_format"     },
    143 	{ EGPR_NOREACH,  "reachability_info_unavailable" },
    144 	{ EGPR_XSPOLL,   "excessive_polling_rate"        },
    145 	{ EGPR_NORESP,   "no_response"                   },
    146 	{ EGPR_UVERSION, "unsupported_version"           },
    147 	{ 0, NULL }
    148 };
    149 
    150 static void
    151 egpnr_print(netdissect_options *ndo,
    152            const struct egp_packet *egp, u_int length)
    153 {
    154 	const uint8_t *cp;
    155 	uint32_t addr;
    156 	uint32_t net;
    157 	u_int netlen;
    158 	u_int gateways, distances, networks;
    159 	u_int intgw, extgw, t_gateways;
    160 	const char *comma;
    161 
    162 	addr = GET_IPV4_TO_NETWORK_ORDER(egp->egp_sourcenet);
    163 	if (IN_CLASSA(addr)) {
    164 		net = addr & IN_CLASSA_NET;
    165 		netlen = 1;
    166 	} else if (IN_CLASSB(addr)) {
    167 		net = addr & IN_CLASSB_NET;
    168 		netlen = 2;
    169 	} else if (IN_CLASSC(addr)) {
    170 		net = addr & IN_CLASSC_NET;
    171 		netlen = 3;
    172 	} else {
    173 		net = 0;
    174 		netlen = 0;
    175 	}
    176 	cp = (const uint8_t *)(egp + 1);
    177 	length -= sizeof(*egp);
    178 
    179 	intgw = GET_U_1(egp->egp_intgw);
    180 	extgw = GET_U_1(egp->egp_extgw);
    181 	t_gateways = intgw + extgw;
    182 	for (gateways = 0; gateways < t_gateways; ++gateways) {
    183 		/* Pickup host part of gateway address */
    184 		addr = 0;
    185 		ND_ICHECK_U(length, <, 4 - netlen);
    186 		ND_TCHECK_LEN(cp, 4 - netlen);
    187 		switch (netlen) {
    188 
    189 		case 1:
    190 			addr = GET_U_1(cp);
    191 			cp++;
    192 			/* fall through */
    193 		case 2:
    194 			addr = (addr << 8) | GET_U_1(cp);
    195 			cp++;
    196 			/* fall through */
    197 		case 3:
    198 			addr = (addr << 8) | GET_U_1(cp);
    199 			cp++;
    200 			break;
    201 		}
    202 		addr |= net;
    203 		length -= 4 - netlen;
    204 		ND_ICHECK_U(length, <, 1);
    205 		distances = GET_U_1(cp);
    206 		cp++;
    207 		length--;
    208 		ND_PRINT(" %s %s ",
    209 		       gateways < intgw ? "int" : "ext",
    210 		       ipaddr_string(ndo, (const u_char *)&addr)); /* local buffer, not packet data; don't use GET_IPADDR_STRING() */
    211 
    212 		comma = "";
    213 		ND_PRINT("(");
    214 		while (distances != 0) {
    215 			ND_ICHECK_U(length, <, 2);
    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 				ND_ICHECK_U(length, <, 1);
    225 				addr = ((uint32_t) GET_U_1(cp)) << 24;
    226 				cp++;
    227 				length--;
    228 				if (IN_CLASSB(addr)) {
    229 					ND_ICHECK_U(length, <, 1);
    230 					addr |= ((uint32_t) GET_U_1(cp)) << 16;
    231 					cp++;
    232 					length--;
    233 				} else if (!IN_CLASSA(addr)) {
    234 					ND_ICHECK_U(length, <, 2);
    235 					addr |= ((uint32_t) GET_U_1(cp)) << 16;
    236 					cp++;
    237 					addr |= ((uint32_t) GET_U_1(cp)) << 8;
    238 					cp++;
    239 					length -= 2;
    240 				}
    241 				ND_PRINT(" %s", ipaddr_string(ndo, (const u_char *)&addr)); /* local buffer, not packet data; don't use GET_IPADDR_STRING() */
    242 				networks--;
    243 			}
    244 			distances--;
    245 		}
    246 		ND_PRINT(")");
    247 	}
    248 	return;
    249 invalid:
    250 	nd_print_invalid(ndo);
    251 }
    252 
    253 void
    254 egp_print(netdissect_options *ndo,
    255           const uint8_t *bp, u_int length)
    256 {
    257 	const struct egp_packet *egp;
    258 	u_int version;
    259 	u_int type;
    260 	u_int code;
    261 	u_int status;
    262 
    263 	ndo->ndo_protocol = "egp";
    264 	nd_print_protocol_caps(ndo);
    265 
    266 	egp = (const struct egp_packet *)bp;
    267 	ND_ICHECK_ZU(length, <, sizeof(*egp));
    268 
    269 	version = GET_U_1(egp->egp_version);
    270 	ND_ICHECK_U(version, !=, EGP_VERSION);
    271 	ND_TCHECK_SIZE(egp);
    272 
    273 	ND_PRINT("v%u", version);
    274 	if (ndo->ndo_vflag) {
    275 		ND_PRINT(", AS %u, seq %u, length %u",
    276 			 GET_BE_U_2(egp->egp_as),
    277 			 GET_BE_U_2(egp->egp_sequence),
    278 			 length);
    279 	} else {
    280 		ND_PRINT(", length %u", length);
    281 		return;
    282 	}
    283 
    284 	type = GET_U_1(egp->egp_type);
    285 	ND_PRINT(", %s", tok2str(egp_type_str, "[type %u]", type));
    286 	code = GET_U_1(egp->egp_code);
    287 	status = GET_U_1(egp->egp_status);
    288 
    289 	switch (type) {
    290 	case EGPT_ACQUIRE:
    291 		ND_PRINT(" %s", tok2str(egp_acquire_codes_str, "[code %u]", code));
    292 		switch (code) {
    293 		case EGPC_REQUEST:
    294 		case EGPC_CONFIRM:
    295 			switch (status) {
    296 			case EGPS_UNSPEC:
    297 			case EGPS_ACTIVE:
    298 			case EGPS_PASSIVE:
    299 				ND_PRINT(" %s", tok2str(egp_acquire_status_str, "%u", status));
    300 				break;
    301 
    302 			default:
    303 				ND_PRINT(" [status %u]", status);
    304 				break;
    305 			}
    306 			ND_PRINT(" hello:%u poll:%u",
    307 			       GET_BE_U_2(egp->egp_hello),
    308 			       GET_BE_U_2(egp->egp_poll));
    309 			break;
    310 
    311 		case EGPC_REFUSE:
    312 		case EGPC_CEASE:
    313 		case EGPC_CEASEACK:
    314 			switch (status ) {
    315 			case EGPS_UNSPEC:
    316 			case EGPS_NORES:
    317 			case EGPS_ADMIN:
    318 			case EGPS_GODOWN:
    319 			case EGPS_PARAM:
    320 			case EGPS_PROTO:
    321 				ND_PRINT(" %s", tok2str(egp_acquire_status_str, "%u", status));
    322 				break;
    323 
    324 			default:
    325 				ND_PRINT("[status %u]", status);
    326 				break;
    327 			}
    328 			break;
    329 		}
    330 		break;
    331 
    332 	case EGPT_REACH:
    333 		ND_PRINT(" %s", tok2str(egp_reach_codes_str, "[reach code %u]", code));
    334 		switch (code) {
    335 		case EGPC_HELLO:
    336 		case EGPC_HEARDU:
    337 			ND_PRINT(" state:%s", tok2str(egp_status_updown_str, "%u", status));
    338 			break;
    339 		}
    340 		break;
    341 
    342 	case EGPT_POLL:
    343 		ND_PRINT(" state:%s", tok2str(egp_status_updown_str, "%u", status));
    344 		ND_PRINT(" net:%s", GET_IPADDR_STRING(egp->egp_sourcenet));
    345 		break;
    346 
    347 	case EGPT_UPDATE:
    348 		if (status & EGPS_UNSOL) {
    349 			status &= ~EGPS_UNSOL;
    350 			ND_PRINT(" unsolicited");
    351 		}
    352 		ND_PRINT(" state:%s", tok2str(egp_status_updown_str, "%u", status));
    353 		ND_PRINT(" %s int %u ext %u",
    354 		       GET_IPADDR_STRING(egp->egp_sourcenet),
    355 		       GET_U_1(egp->egp_intgw),
    356 		       GET_U_1(egp->egp_extgw));
    357 		if (ndo->ndo_vflag)
    358 			egpnr_print(ndo, egp, length);
    359 		break;
    360 
    361 	case EGPT_ERROR:
    362 		ND_PRINT(" state:%s", tok2str(egp_status_updown_str, "%u", status));
    363 		ND_PRINT(" %s", tok2str(egp_reasons_str, "[reason %u]", GET_BE_U_2(egp->egp_reason)));
    364 		break;
    365 	}
    366 	return;
    367 invalid:
    368 	nd_print_invalid(ndo);
    369 }
    370