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#include "netdissect.h"
32#include "addrtoname.h"
33#include "extract.h"
34
35struct egp_packet {
36	nd_uint8_t  egp_version;
37#define	EGP_VERSION	2
38	nd_uint8_t  egp_type;
39#define  EGPT_ACQUIRE	3
40#define  EGPT_REACH	5
41#define  EGPT_POLL	2
42#define  EGPT_UPDATE	1
43#define  EGPT_ERROR	8
44	nd_uint8_t  egp_code;
45#define  EGPC_REQUEST	0
46#define  EGPC_CONFIRM	1
47#define  EGPC_REFUSE	2
48#define  EGPC_CEASE	3
49#define  EGPC_CEASEACK	4
50#define  EGPC_HELLO	0
51#define  EGPC_HEARDU	1
52	nd_uint8_t  egp_status;
53#define  EGPS_UNSPEC	0
54#define  EGPS_ACTIVE	1
55#define  EGPS_PASSIVE	2
56#define  EGPS_NORES	3
57#define  EGPS_ADMIN	4
58#define  EGPS_GODOWN	5
59#define  EGPS_PARAM	6
60#define  EGPS_PROTO	7
61#define  EGPS_INDET	0
62#define  EGPS_UP	1
63#define  EGPS_DOWN	2
64#define  EGPS_UNSOL	0x80
65	nd_uint16_t  egp_checksum;
66	nd_uint16_t  egp_as;
67	nd_uint16_t  egp_sequence;
68	union {
69		nd_uint16_t egpu_hello;
70		nd_uint8_t  egpu_gws[2];
71		nd_uint16_t egpu_reason;
72#define  EGPR_UNSPEC	0
73#define  EGPR_BADHEAD	1
74#define  EGPR_BADDATA	2
75#define  EGPR_NOREACH	3
76#define  EGPR_XSPOLL	4
77#define  EGPR_NORESP	5
78#define  EGPR_UVERSION	6
79	} egp_handg;
80#define  egp_hello  egp_handg.egpu_hello
81#define  egp_intgw  egp_handg.egpu_gws[0]
82#define  egp_extgw  egp_handg.egpu_gws[1]
83#define  egp_reason  egp_handg.egpu_reason
84	union {
85		nd_uint16_t egpu_poll;
86		nd_ipv4 egpu_sourcenet;
87	} egp_pands;
88#define  egp_poll  egp_pands.egpu_poll
89#define  egp_sourcenet  egp_pands.egpu_sourcenet
90};
91
92static const char *egp_acquire_codes[] = {
93	"request",
94	"confirm",
95	"refuse",
96	"cease",
97	"cease_ack"
98};
99
100static const char *egp_acquire_status[] = {
101	"unspecified",
102	"active_mode",
103	"passive_mode",
104	"insufficient_resources",
105	"administratively_prohibited",
106	"going_down",
107	"parameter_violation",
108	"protocol_violation"
109};
110
111static const char *egp_reach_codes[] = {
112	"hello",
113	"i-h-u"
114};
115
116static const char *egp_status_updown[] = {
117	"indeterminate",
118	"up",
119	"down"
120};
121
122static const char *egp_reasons[] = {
123	"unspecified",
124	"bad_EGP_header_format",
125	"bad_EGP_data_field_format",
126	"reachability_info_unavailable",
127	"excessive_polling_rate",
128	"no_response",
129	"unsupported_version"
130};
131
132static void
133egpnr_print(netdissect_options *ndo,
134           const struct egp_packet *egp, u_int length)
135{
136	const uint8_t *cp;
137	uint32_t addr;
138	uint32_t net;
139	u_int netlen;
140	u_int gateways, distances, networks;
141	u_int intgw, extgw, t_gateways;
142	const char *comma;
143
144	addr = GET_IPV4_TO_NETWORK_ORDER(egp->egp_sourcenet);
145	if (IN_CLASSA(addr)) {
146		net = addr & IN_CLASSA_NET;
147		netlen = 1;
148	} else if (IN_CLASSB(addr)) {
149		net = addr & IN_CLASSB_NET;
150		netlen = 2;
151	} else if (IN_CLASSC(addr)) {
152		net = addr & IN_CLASSC_NET;
153		netlen = 3;
154	} else {
155		net = 0;
156		netlen = 0;
157	}
158	cp = (const uint8_t *)(egp + 1);
159	length -= sizeof(*egp);
160
161	intgw = GET_U_1(egp->egp_intgw);
162	extgw = GET_U_1(egp->egp_extgw);
163	t_gateways = intgw + extgw;
164	for (gateways = 0; gateways < t_gateways; ++gateways) {
165		/* Pickup host part of gateway address */
166		addr = 0;
167		if (length < 4 - netlen)
168			goto trunc;
169		ND_TCHECK_LEN(cp, 4 - netlen);
170		switch (netlen) {
171
172		case 1:
173			addr = GET_U_1(cp);
174			cp++;
175			/* fall through */
176		case 2:
177			addr = (addr << 8) | GET_U_1(cp);
178			cp++;
179			/* fall through */
180		case 3:
181			addr = (addr << 8) | GET_U_1(cp);
182			cp++;
183			break;
184		}
185		addr |= net;
186		length -= 4 - netlen;
187		if (length < 1)
188			goto trunc;
189		distances = GET_U_1(cp);
190		cp++;
191		length--;
192		ND_PRINT(" %s %s ",
193		       gateways < intgw ? "int" : "ext",
194		       ipaddr_string(ndo, (const u_char *)&addr)); /* local buffer, not packet data; don't use GET_IPADDR_STRING() */
195
196		comma = "";
197		ND_PRINT("(");
198		while (distances != 0) {
199			if (length < 2)
200				goto trunc;
201			ND_PRINT("%sd%u:", comma, GET_U_1(cp));
202			cp++;
203			comma = ", ";
204			networks = GET_U_1(cp);
205			cp++;
206			length -= 2;
207			while (networks != 0) {
208				/* Pickup network number */
209				if (length < 1)
210					goto trunc;
211				addr = ((uint32_t) GET_U_1(cp)) << 24;
212				cp++;
213				length--;
214				if (IN_CLASSB(addr)) {
215					if (length < 1)
216						goto trunc;
217					addr |= ((uint32_t) GET_U_1(cp)) << 16;
218					cp++;
219					length--;
220				} else if (!IN_CLASSA(addr)) {
221					if (length < 2)
222						goto trunc;
223					addr |= ((uint32_t) GET_U_1(cp)) << 16;
224					cp++;
225					addr |= ((uint32_t) GET_U_1(cp)) << 8;
226					cp++;
227					length -= 2;
228				}
229				ND_PRINT(" %s", ipaddr_string(ndo, (const u_char *)&addr)); /* local buffer, not packet data; don't use GET_IPADDR_STRING() */
230				networks--;
231			}
232			distances--;
233		}
234		ND_PRINT(")");
235	}
236	return;
237trunc:
238	nd_print_trunc(ndo);
239}
240
241void
242egp_print(netdissect_options *ndo,
243          const uint8_t *bp, u_int length)
244{
245	const struct egp_packet *egp;
246	u_int version;
247	u_int type;
248	u_int code;
249	u_int status;
250
251	ndo->ndo_protocol = "egp";
252	egp = (const struct egp_packet *)bp;
253	if (length < sizeof(*egp) || !ND_TTEST_SIZE(egp)) {
254		nd_print_trunc(ndo);
255		return;
256	}
257
258	version = GET_U_1(egp->egp_version);
259        if (!ndo->ndo_vflag) {
260            ND_PRINT("EGPv%u, AS %u, seq %u, length %u",
261                   version,
262                   GET_BE_U_2(egp->egp_as),
263                   GET_BE_U_2(egp->egp_sequence),
264                   length);
265            return;
266        } else
267            ND_PRINT("EGPv%u, length %u",
268                   version,
269                   length);
270
271	if (version != EGP_VERSION) {
272		ND_PRINT("[version %u]", version);
273		return;
274	}
275
276	type = GET_U_1(egp->egp_type);
277	code = GET_U_1(egp->egp_code);
278	status = GET_U_1(egp->egp_status);
279
280	switch (type) {
281	case EGPT_ACQUIRE:
282		ND_PRINT(" acquire");
283		switch (code) {
284		case EGPC_REQUEST:
285		case EGPC_CONFIRM:
286			ND_PRINT(" %s", egp_acquire_codes[code]);
287			switch (status) {
288			case EGPS_UNSPEC:
289			case EGPS_ACTIVE:
290			case EGPS_PASSIVE:
291				ND_PRINT(" %s", egp_acquire_status[status]);
292				break;
293
294			default:
295				ND_PRINT(" [status %u]", status);
296				break;
297			}
298			ND_PRINT(" hello:%u poll:%u",
299			       GET_BE_U_2(egp->egp_hello),
300			       GET_BE_U_2(egp->egp_poll));
301			break;
302
303		case EGPC_REFUSE:
304		case EGPC_CEASE:
305		case EGPC_CEASEACK:
306			ND_PRINT(" %s", egp_acquire_codes[code]);
307			switch (status ) {
308			case EGPS_UNSPEC:
309			case EGPS_NORES:
310			case EGPS_ADMIN:
311			case EGPS_GODOWN:
312			case EGPS_PARAM:
313			case EGPS_PROTO:
314				ND_PRINT(" %s", egp_acquire_status[status]);
315				break;
316
317			default:
318				ND_PRINT("[status %u]", status);
319				break;
320			}
321			break;
322
323		default:
324			ND_PRINT("[code %u]", code);
325			break;
326		}
327		break;
328
329	case EGPT_REACH:
330		switch (code) {
331
332		case EGPC_HELLO:
333		case EGPC_HEARDU:
334			ND_PRINT(" %s", egp_reach_codes[code]);
335			if (status <= EGPS_DOWN)
336				ND_PRINT(" state:%s", egp_status_updown[status]);
337			else
338				ND_PRINT(" [status %u]", status);
339			break;
340
341		default:
342			ND_PRINT("[reach code %u]", code);
343			break;
344		}
345		break;
346
347	case EGPT_POLL:
348		ND_PRINT(" poll");
349		if (status <= EGPS_DOWN)
350			ND_PRINT(" state:%s", egp_status_updown[status]);
351		else
352			ND_PRINT(" [status %u]", status);
353		ND_PRINT(" net:%s", GET_IPADDR_STRING(egp->egp_sourcenet));
354		break;
355
356	case EGPT_UPDATE:
357		ND_PRINT(" update");
358		if (status & EGPS_UNSOL) {
359			status &= ~EGPS_UNSOL;
360			ND_PRINT(" unsolicited");
361		}
362		if (status <= EGPS_DOWN)
363			ND_PRINT(" state:%s", egp_status_updown[status]);
364		else
365			ND_PRINT(" [status %u]", status);
366		ND_PRINT(" %s int %u ext %u",
367		       GET_IPADDR_STRING(egp->egp_sourcenet),
368		       GET_U_1(egp->egp_intgw),
369		       GET_U_1(egp->egp_extgw));
370		if (ndo->ndo_vflag)
371			egpnr_print(ndo, egp, length);
372		break;
373
374	case EGPT_ERROR:
375		ND_PRINT(" error");
376		if (status <= EGPS_DOWN)
377			ND_PRINT(" state:%s", egp_status_updown[status]);
378		else
379			ND_PRINT(" [status %u]", status);
380
381		if (GET_BE_U_2(egp->egp_reason) <= EGPR_UVERSION)
382			ND_PRINT(" %s",
383				 egp_reasons[GET_BE_U_2(egp->egp_reason)]);
384		else
385			ND_PRINT(" [reason %u]", GET_BE_U_2(egp->egp_reason));
386		break;
387
388	default:
389		ND_PRINT("[type %u]", type);
390		break;
391	}
392}
393