xref: /freebsd/contrib/tcpdump/print-bgp.c (revision 23f282aa31e9b6fceacd449020e936e98d6f2298)
1 /*
2  * Copyright (C) 1999 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #ifdef HAVE_CONFIG_H
31 #include "config.h"
32 #endif
33 
34 #ifndef lint
35 static const char rcsid[] =
36      "@(#) $Header: /tcpdump/master/tcpdump/print-bgp.c,v 1.9.2.2 2000/01/25 18:32:53 itojun Exp $";
37 #endif
38 
39 #include <sys/param.h>
40 #include <sys/time.h>
41 #include <sys/types.h>
42 #include <sys/socket.h>
43 
44 #include <netinet/in.h>
45 #include <netinet/in_systm.h>
46 #include <netinet/ip.h>
47 #include <netinet/ip_var.h>
48 #include <netinet/udp.h>
49 #include <netinet/udp_var.h>
50 
51 #include <errno.h>
52 #include <stdio.h>
53 #include <string.h>
54 
55 #include "interface.h"
56 #include "addrtoname.h"
57 
58 struct bgp {
59 	u_int8_t bgp_marker[16];
60 	u_int16_t bgp_len;
61 	u_int8_t bgp_type;
62 };
63 #define BGP_SIZE		19	/* unaligned */
64 
65 #define BGP_OPEN		1
66 #define BGP_UPDATE		2
67 #define BGP_NOTIFICATION	3
68 #define BGP_KEEPALIVE		4
69 
70 struct bgp_open {
71 	u_int8_t bgpo_marker[16];
72 	u_int16_t bgpo_len;
73 	u_int8_t bgpo_type;
74 	u_int8_t bgpo_version;
75 	u_int16_t bgpo_myas;
76 	u_int16_t bgpo_holdtime;
77 	u_int32_t bgpo_id;
78 	u_int8_t bgpo_optlen;
79 	/* options should follow */
80 };
81 
82 struct bgp_opt {
83 	u_int8_t bgpopt_type;
84 	u_int8_t bgpopt_len;
85 	/* variable length */
86 };
87 
88 struct bgp_notification {
89 	u_int8_t bgpn_marker[16];
90 	u_int16_t bgpn_len;
91 	u_int8_t bgpn_type;
92 	u_int8_t bgpn_major;
93 	u_int8_t bgpn_minor;
94 	/* data should follow */
95 };
96 
97 struct bgp_attr {
98 	u_int8_t bgpa_flags;
99 	u_int8_t bgpa_type;
100 	union {
101 		u_int8_t len;
102 		u_int16_t elen;
103 	} bgpa_len;
104 #define bgp_attr_len(p) \
105 	(((p)->bgpa_flags & 0x10) ? \
106 		ntohs((p)->bgpa_len.elen) : (p)->bgpa_len.len)
107 #define bgp_attr_off(p) \
108 	(((p)->bgpa_flags & 0x10) ? 4 : 3)
109 };
110 
111 #define BGPTYPE_ORIGIN			1
112 #define BGPTYPE_AS_PATH			2
113 #define BGPTYPE_NEXT_HOP		3
114 #define BGPTYPE_MULTI_EXIT_DISC		4
115 #define BGPTYPE_LOCAL_PREF		5
116 #define BGPTYPE_ATOMIC_AGGREGATE	6
117 #define BGPTYPE_AGGREGATOR		7
118 #define	BGPTYPE_COMMUNITIES		8	/* RFC1997 */
119 #define	BGPTYPE_ORIGINATOR_ID		9	/* RFC1998 */
120 #define	BGPTYPE_CLUSTER_LIST		10	/* RFC1998 */
121 #define	BGPTYPE_DPA			11	/* work in progress */
122 #define	BGPTYPE_ADVERTISERS		12	/* RFC1863 */
123 #define	BGPTYPE_RCID_PATH		13	/* RFC1863 */
124 #define BGPTYPE_MP_REACH_NLRI		14	/* RFC2283 */
125 #define BGPTYPE_MP_UNREACH_NLRI		15	/* RFC2283 */
126 
127 
128 static const char *bgptype[] = {
129 	NULL, "OPEN", "UPDATE", "NOTIFICATION", "KEEPALIVE",
130 };
131 #define bgp_type(x) num_or_str(bgptype, sizeof(bgptype)/sizeof(bgptype[0]), (x))
132 
133 static const char *bgpopt_type[] = {
134 	NULL, "Authentication Information",
135 };
136 #define bgp_opttype(x) \
137 	num_or_str(bgpopt_type, sizeof(bgpopt_type)/sizeof(bgpopt_type[0]), (x))
138 
139 static const char *bgpnotify_major[] = {
140 	NULL, "Message Header Error",
141 	"OPEN Message Error", "UPDATE Message Error",
142 	"Hold Timer Expired", "Finite State Machine Error",
143 	"Cease",
144 };
145 #define bgp_notify_major(x) \
146 	num_or_str(bgpnotify_major, \
147 		sizeof(bgpnotify_major)/sizeof(bgpnotify_major[0]), (x))
148 
149 static const char *bgpnotify_minor_1[] = {
150 	NULL, "Connection Not Synchronized",
151 	"Bad Message Length", "Bad Message Type",
152 };
153 
154 static const char *bgpnotify_minor_2[] = {
155 	NULL, "Unsupported Version Number",
156 	"Bad Peer AS", "Bad BGP Identifier",
157 	"Unsupported Optional Parameter", "Authentication Failure",
158 	"Unacceptable Hold Time",
159 };
160 
161 static const char *bgpnotify_minor_3[] = {
162 	NULL, "Malformed Attribute List",
163 	"Unrecognized Well-known Attribute", "Missing Well-known Attribute",
164 	"Attribute Flags Error", "Attribute Length Error",
165 	"Invalid ORIGIN Attribute", "AS Routing Loop",
166 	"Invalid NEXT_HOP Attribute", "Optional Attribute Error",
167 	"Invalid Network Field", "Malformed AS_PATH",
168 };
169 
170 static const char **bgpnotify_minor[] = {
171 	NULL, bgpnotify_minor_1, bgpnotify_minor_2, bgpnotify_minor_3,
172 };
173 static const int bgpnotify_minor_siz[] = {
174 	0, sizeof(bgpnotify_minor_1)/sizeof(bgpnotify_minor_1[0]),
175 	sizeof(bgpnotify_minor_2)/sizeof(bgpnotify_minor_2[0]),
176 	sizeof(bgpnotify_minor_3)/sizeof(bgpnotify_minor_3[0]),
177 };
178 
179 static const char *bgpattr_origin[] = {
180 	"IGP", "EGP", "INCOMPLETE",
181 };
182 #define bgp_attr_origin(x) \
183 	num_or_str(bgpattr_origin, \
184 		sizeof(bgpattr_origin)/sizeof(bgpattr_origin[0]), (x))
185 
186 static const char *bgpattr_type[] = {
187 	NULL, "ORIGIN", "AS_PATH", "NEXT_HOP",
188 	"MULTI_EXIT_DISC", "LOCAL_PREF", "ATOMIC_AGGREGATE", "AGGREGATOR",
189 	"COMMUNITIES", "ORIGINATOR_ID", "CLUSTER_LIST", "DPA",
190 	"ADVERTISERS", "RCID_PATH", "MP_REACH_NLRI", "MP_UNREACH_NLRI",
191 };
192 #define bgp_attr_type(x) \
193 	num_or_str(bgpattr_type, \
194 		sizeof(bgpattr_type)/sizeof(bgpattr_type[0]), (x))
195 
196 /* Subsequent address family identifier, RFC2283 section 7 */
197 static const char *bgpattr_nlri_safi[] = {
198     "Reserved", "Unicast", "Multicast", "Unicast+Multicast",
199 };
200 #define bgp_attr_nlri_safi(x) \
201 	num_or_str(bgpattr_nlri_safi, \
202 		sizeof(bgpattr_nlri_safi)/sizeof(bgpattr_nlri_safi[0]), (x))
203 
204 /* well-known community */
205 #define BGP_COMMUNITY_NO_EXPORT			0xffffff01
206 #define BGP_COMMUNITY_NO_ADVERT			0xffffff02
207 #define BGP_COMMUNITY_NO_EXPORT_SUBCONFED	0xffffff03
208 
209 /* RFC1700 address family numbers */
210 #define AFNUM_INET	1
211 #define AFNUM_INET6	2
212 #define AFNUM_NSAP	3
213 #define AFNUM_HDLC	4
214 #define AFNUM_BBN1822	5
215 #define AFNUM_802	6
216 #define AFNUM_E163	7
217 #define AFNUM_E164	8
218 #define AFNUM_F69	9
219 #define AFNUM_X121	10
220 #define AFNUM_IPX	11
221 #define AFNUM_ATALK	12
222 #define AFNUM_DECNET	13
223 #define AFNUM_BANYAN	14
224 #define AFNUM_E164NSAP	15
225 
226 static const char *afnumber[] = {
227 	"Reserved", "IPv4", "IPv6", "NSAP", "HDLC",
228 	"BBN 1822", "802", "E.163", "E.164", "F.69",
229 	"X.121", "IPX", "Appletalk", "Decnet IV", "Banyan Vines",
230 	"E.164 with NSAP subaddress",
231 };
232 #define af_name(x) \
233 	(((x) == 65535) ? afnumber[0] : \
234 		num_or_str(afnumber, \
235 			sizeof(afnumber)/sizeof(afnumber[0]), (x)))
236 
237 
238 static const char *
239 num_or_str(const char **table, size_t siz, int value)
240 {
241 	static char buf[20];
242 	if (value < 0 || siz <= value || table[value] == NULL) {
243 		sprintf(buf, "#%d", value);
244 		return buf;
245 	} else
246 		return table[value];
247 }
248 
249 static const char *
250 bgp_notify_minor(int major, int minor)
251 {
252 	static const char **table;
253 	int siz;
254 	static char buf[20];
255 	const char *p;
256 
257 	if (0 <= major
258 	 && major < sizeof(bgpnotify_minor)/sizeof(bgpnotify_minor[0])
259 	 && bgpnotify_minor[major]) {
260 		table = bgpnotify_minor[major];
261 		siz = bgpnotify_minor_siz[major];
262 		if (0 <= minor && minor < siz && table[minor])
263 			p = table[minor];
264 		else
265 			p = NULL;
266 	} else
267 		p = NULL;
268 	if (p == NULL) {
269 		sprintf(buf, "#%d", minor);
270 		return buf;
271 	} else
272 		return p;
273 }
274 
275 static int
276 decode_prefix4(const u_char *pd, char *buf, int buflen)
277 {
278 	struct in_addr addr;
279 	int plen;
280 
281 	plen = pd[0];
282 	if (plen < 0 || 32 < plen)
283 		return -1;
284 
285 	memset(&addr, 0, sizeof(addr));
286 	memcpy(&addr, &pd[1], (plen + 7) / 8);
287 	if (plen % 8) {
288 		((u_char *)&addr)[(plen + 7) / 8 - 1] &=
289 			((0xff00 >> (plen % 8)) & 0xff);
290 	}
291 	sprintf(buf, "%s/%d", getname((char *)&addr), plen);
292 	return 1 + (plen + 7) / 8;
293 }
294 
295 #ifdef INET6
296 static int
297 decode_prefix6(const u_char *pd, char *buf, int buflen)
298 {
299 	struct in6_addr addr;
300 	int plen;
301 
302 	plen = pd[0];
303 	if (plen < 0 || 128 < plen)
304 		return -1;
305 
306 	memset(&addr, 0, sizeof(addr));
307 	memcpy(&addr, &pd[1], (plen + 7) / 8);
308 	if (plen % 8) {
309 		addr.s6_addr[(plen + 7) / 8 - 1] &=
310 			((0xff00 >> (plen % 8)) & 0xff);
311 	}
312 	sprintf(buf, "%s/%d", getname6((char *)&addr), plen);
313 	return 1 + (plen + 7) / 8;
314 }
315 #endif
316 
317 static void
318 bgp_attr_print(const struct bgp_attr *attr, const u_char *dat, int len)
319 {
320 	int i;
321 	u_int16_t af;
322 	u_int8_t safi, snpa;
323 	int advance;
324 	int tlen;
325 	const u_char *p;
326 	char buf[256];
327 
328 	p = dat;
329 
330 	switch (attr->bgpa_type) {
331 	case BGPTYPE_ORIGIN:
332 		if (len != 1)
333 			printf(" invalid len");
334 		else
335 			printf(" %s", bgp_attr_origin(p[0]));
336 		break;
337 	case BGPTYPE_AS_PATH:
338 		if (len % 2) {
339 			printf(" invalid len");
340 			break;
341 		}
342 		while (p < dat + len) {
343 			/*
344 			 * under RFC1965, p[0] means:
345 			 * 1: AS_SET 2: AS_SEQUENCE
346 			 * 3: AS_CONFED_SET 4: AS_CONFED_SEQUENCE
347 			 */
348 			printf(" ");
349 			if (p[0] == 3 || p[0] == 4)
350 				printf("confed");
351 			printf("%s", (p[0] & 1) ? "{" : "");
352 			for (i = 0; i < p[1]; i += 2) {
353 				printf("%s%u", i == 0 ? "" : " ",
354 					ntohs(*(u_int16_t *)&p[2 + i]));
355 			}
356 			printf("%s", (p[0] & 1) ? "}" : "");
357 			p += 2 + p[1] * 2;
358 		}
359 		break;
360 	case BGPTYPE_NEXT_HOP:
361 		if (len != 4)
362 			printf(" invalid len");
363 		else
364 			printf(" %s", getname(p));
365 		break;
366 	case BGPTYPE_MULTI_EXIT_DISC:
367 	case BGPTYPE_LOCAL_PREF:
368 		if (len != 4)
369 			printf(" invalid len");
370 		else
371 			printf(" %u", (u_int32_t)ntohl(*(u_int32_t *)p));
372 		break;
373 	case BGPTYPE_ATOMIC_AGGREGATE:
374 		if (len != 0)
375 			printf(" invalid len");
376 		break;
377 	case BGPTYPE_AGGREGATOR:
378 		if (len != 6) {
379 			printf(" invalid len");
380 			break;
381 		}
382 		printf(" AS #%u, origin %s", ntohs(*(u_int16_t *)p),
383 			getname(p + 2));
384 		break;
385 	case BGPTYPE_COMMUNITIES:
386 		if (len % 4) {
387 			printf(" invalid len");
388 			break;
389 		}
390 		for (i = 0; i < len; i += 4) {
391 			u_int32_t comm;
392 			comm = (u_int32_t)ntohl(*(u_int32_t *)&p[i]);
393 			switch (comm) {
394 			case BGP_COMMUNITY_NO_EXPORT:
395 				printf(" NO_EXPORT");
396 				break;
397 			case BGP_COMMUNITY_NO_ADVERT:
398 				printf(" NO_ADVERTISE");
399 				break;
400 			case BGP_COMMUNITY_NO_EXPORT_SUBCONFED:
401 				printf(" NO_EXPORT_SUBCONFED");
402 				break;
403 			default:
404 				printf(" (AS #%d value 0x%04x)",
405 					(comm >> 16) & 0xffff, comm & 0xffff);
406 				break;
407 			}
408 		}
409 		break;
410 	case BGPTYPE_MP_REACH_NLRI:
411 		af = ntohs(*(u_int16_t *)p);
412 		safi = p[2];
413 		if (safi >= 128)
414 			printf(" %s vendor specific,", af_name(af));
415 		else {
416 			printf(" %s %s,", af_name(af),
417 				bgp_attr_nlri_safi(safi));
418 		}
419 		p += 3;
420 
421 		if (af == AFNUM_INET)
422 			;
423 #ifdef INET6
424 		else if (af == AFNUM_INET6)
425 			;
426 #endif
427 		else
428 			break;
429 
430 		tlen = p[0];
431 		if (tlen) {
432 			printf(" nexthop");
433 			if (af == AFNUM_INET)
434 				advance = 4;
435 #ifdef INET6
436 			else if (af == AFNUM_INET6)
437 				advance = 16;
438 #endif
439 
440 			for (i = 0; i < tlen; i += advance) {
441 				if (af == AFNUM_INET)
442 					printf(" %s", getname(p + 1 + i));
443 #ifdef INET6
444 				else if (af == AFNUM_INET6)
445 					printf(" %s", getname6(p + 1 + i));
446 #endif
447 			}
448 			printf(",");
449 		}
450 		p += 1 + tlen;
451 
452 		snpa = p[0];
453 		p++;
454 		if (snpa) {
455 			printf(" %u snpa", snpa);
456 			for (/*nothing*/; snpa > 0; snpa--) {
457 				printf("(%d bytes)", p[0]);
458 				p += p[0] + 1;
459 			}
460 			printf(",");
461 		}
462 
463 		printf(" NLRI");
464 		while (len - (p - dat) > 0) {
465 			if (af == AFNUM_INET)
466 				advance = decode_prefix4(p, buf, sizeof(buf));
467 #ifdef INET6
468 			else if (af == AFNUM_INET6)
469 				advance = decode_prefix6(p, buf, sizeof(buf));
470 #endif
471 			printf(" %s", buf);
472 
473 			p += advance;
474 		}
475 
476 		break;
477 
478 	case BGPTYPE_MP_UNREACH_NLRI:
479 		af = ntohs(*(u_int16_t *)p);
480 		safi = p[2];
481 		if (safi >= 128)
482 			printf(" %s vendor specific,", af_name(af));
483 		else {
484 			printf(" %s %s,", af_name(af),
485 				bgp_attr_nlri_safi(safi));
486 		}
487 		p += 3;
488 
489 		printf(" Withdraw");
490 		while (len - (p - dat) > 0) {
491 			if (af == AFNUM_INET)
492 				advance = decode_prefix4(p, buf, sizeof(buf));
493 #ifdef INET6
494 			else if (af == AFNUM_INET6)
495 				advance = decode_prefix6(p, buf, sizeof(buf));
496 #endif
497 			printf(" %s", buf);
498 
499 			p += advance;
500 		}
501 		break;
502 	default:
503 		break;
504 	}
505 }
506 
507 static void
508 bgp_open_print(const u_char *dat, int length)
509 {
510 	struct bgp_open bgpo;
511 	struct bgp_opt bgpopt;
512 	int hlen;
513 	const u_char *opt;
514 	int i;
515 
516 	memcpy(&bgpo, dat, sizeof(bgpo));
517 	hlen = ntohs(bgpo.bgpo_len);
518 
519 	printf(": Version %d,", bgpo.bgpo_version);
520 	printf(" AS #%u,", ntohs(bgpo.bgpo_myas));
521 	printf(" Holdtime %u,", ntohs(bgpo.bgpo_holdtime));
522 	printf(" ID %s,", getname((char *)&bgpo.bgpo_id));
523 	printf(" Option length %u", bgpo.bgpo_optlen);
524 
525 	/* ugly! */
526 	opt = &((struct bgp_open *)dat)->bgpo_optlen;
527 	opt++;
528 
529 	for (i = 0; i < bgpo.bgpo_optlen; i++) {
530 		memcpy(&bgpopt, &opt[i], sizeof(bgpopt));
531 		if (i + 2 + bgpopt.bgpopt_len > bgpo.bgpo_optlen) {
532 			printf(" [|opt %d %d]", bgpopt.bgpopt_len, bgpopt.bgpopt_type);
533 			break;
534 		}
535 
536 		printf(" (option %s, len=%d)", bgp_opttype(bgpopt.bgpopt_type),
537 			bgpopt.bgpopt_len);
538 		i += sizeof(bgpopt) + bgpopt.bgpopt_len;
539 	}
540 }
541 
542 static void
543 bgp_update_print(const u_char *dat, int length)
544 {
545 	struct bgp bgp;
546 	struct bgp_attr bgpa;
547 	int hlen;
548 	const u_char *p;
549 	int len;
550 	int i;
551 	int newline;
552 
553 	memcpy(&bgp, dat, sizeof(bgp));
554 	hlen = ntohs(bgp.bgp_len);
555 	p = dat + BGP_SIZE;	/*XXX*/
556 	printf(":");
557 
558 	/* Unfeasible routes */
559 	len = ntohs(*(u_int16_t *)p);
560 	if (len) {
561 		printf(" (Withdrawn routes: %d bytes)", len);
562 	}
563 	p += 2 + len;
564 
565 	len = ntohs(*(u_int16_t *)p);
566 	if (len) {
567 		/* do something more useful!*/
568 		i = 2;
569 		printf(" (Path attributes:");	/* ) */
570 		newline = 0;
571 		while (i < 2 + len) {
572 			int alen, aoff;
573 
574 			memcpy(&bgpa, &p[i], sizeof(bgpa));
575 			alen = bgp_attr_len(&bgpa);
576 			aoff = bgp_attr_off(&bgpa);
577 
578 			if (vflag && newline)
579 				printf("\n\t\t");
580 			else
581 				printf(" ");
582 			printf("(");		/* ) */
583 			printf("%s", bgp_attr_type(bgpa.bgpa_type));
584 			if (bgpa.bgpa_flags) {
585 				printf("[%s%s%s%s]",
586 					bgpa.bgpa_flags & 0x80 ? "O" : "",
587 					bgpa.bgpa_flags & 0x40 ? "T" : "",
588 					bgpa.bgpa_flags & 0x20 ? "P" : "",
589 					bgpa.bgpa_flags & 0x00 ? "E" : "");
590 			}
591 
592 			bgp_attr_print(&bgpa, &p[i + aoff], alen);
593 			newline = 1;
594 
595 			/* ( */
596 			printf(")");
597 
598 			i += aoff + alen;
599 		}
600 
601 		/* ( */
602 		printf(")");
603 	}
604 	p += 2 + len;
605 
606 	if (len && dat + length > p)
607 		printf("\n\t\t");
608 	if (dat + length > p) {
609 		printf("(NLRI:");	/* ) */
610 		while (dat + length > p) {
611 			char buf[256];
612 			i = decode_prefix4(p, buf, sizeof(buf));
613 			printf(" %s", buf);
614 			if (i < 0)
615 				break;
616 			p += i;
617 		}
618 
619 		/* ( */
620 		printf(")");
621 	}
622 }
623 
624 static void
625 bgp_notification_print(const u_char *dat, int length)
626 {
627 	struct bgp_notification bgpn;
628 	int hlen;
629 
630 	memcpy(&bgpn, dat, sizeof(bgpn));
631 	hlen = ntohs(bgpn.bgpn_len);
632 
633 	printf(": error %s,", bgp_notify_major(bgpn.bgpn_major));
634 	printf(" subcode %s",
635 		bgp_notify_minor(bgpn.bgpn_major, bgpn.bgpn_minor));
636 }
637 
638 static void
639 bgp_header_print(const u_char *dat, int length)
640 {
641 	struct bgp bgp;
642 
643 	memcpy(&bgp, dat, sizeof(bgp));
644 	printf("(%s", bgp_type(bgp.bgp_type));		/* ) */
645 
646 	switch (bgp.bgp_type) {
647 	case BGP_OPEN:
648 		bgp_open_print(dat, length);
649 		break;
650 	case BGP_UPDATE:
651 		bgp_update_print(dat, length);
652 		break;
653 	case BGP_NOTIFICATION:
654 		bgp_notification_print(dat, length);
655 		break;
656 	}
657 
658 	/* ( */
659 	printf(")");
660 }
661 
662 void
663 bgp_print(const u_char *dat, int length)
664 {
665 	const u_char *p;
666 	const u_char *ep;
667 	const u_char *start;
668 	const u_char marker[] = {
669 		0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
670 		0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
671 	};
672 	struct bgp bgp;
673 	u_int16_t hlen;
674 	int newline;
675 
676 	ep = dat + length;
677 	if (snapend < dat + length)
678 		ep = snapend;
679 
680 	printf(": BGP");
681 
682 	p = dat;
683 	newline = 0;
684 	start = p;
685 	while (p < snapend) {
686 		if (!TTEST2(p[0], 1))
687 			break;
688 		if (p[0] != 0xff) {
689 			p++;
690 			continue;
691 		}
692 
693 		if (!TTEST2(p[0], sizeof(marker)))
694 			break;
695 		if (memcmp(p, marker, sizeof(marker)) != 0) {
696 			p++;
697 			continue;
698 		}
699 
700 		/* found BGP header */
701 		TCHECK2(p[0], BGP_SIZE);	/*XXX*/
702 		memcpy(&bgp, p, sizeof(bgp));
703 
704 		if (start != p)
705 			printf(" [|BGP]");
706 
707 		hlen = ntohs(bgp.bgp_len);
708 		if (vflag && newline)
709 			printf("\n\t");
710 		else
711 			printf(" ");
712 		if (TTEST2(p[0], hlen)) {
713 			bgp_header_print(p, hlen);
714 			newline = 1;
715 			p += hlen;
716 			start = p;
717 		} else {
718 			printf("[|BGP %s]", bgp_type(bgp.bgp_type));
719 			break;
720 		}
721 	}
722 
723 	return;
724 
725 trunc:
726 	printf(" [|BGP]");
727 }
728