xref: /freebsd/contrib/tcpdump/print-bgp.c (revision a3e8fd0b7f663db7eafff527d5c3ca3bcfa8a537)
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 1.27 2001/10/18 09:52:17 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 
46 #include <errno.h>
47 #include <stdio.h>
48 #include <string.h>
49 #include <netdb.h>
50 
51 #include "interface.h"
52 #include "addrtoname.h"
53 #include "extract.h"
54 
55 struct bgp {
56 	u_int8_t bgp_marker[16];
57 	u_int16_t bgp_len;
58 	u_int8_t bgp_type;
59 };
60 #define BGP_SIZE		19	/* unaligned */
61 
62 #define BGP_OPEN		1
63 #define BGP_UPDATE		2
64 #define BGP_NOTIFICATION	3
65 #define BGP_KEEPALIVE		4
66 
67 struct bgp_open {
68 	u_int8_t bgpo_marker[16];
69 	u_int16_t bgpo_len;
70 	u_int8_t bgpo_type;
71 	u_int8_t bgpo_version;
72 	u_int16_t bgpo_myas;
73 	u_int16_t bgpo_holdtime;
74 	u_int32_t bgpo_id;
75 	u_int8_t bgpo_optlen;
76 	/* options should follow */
77 };
78 #define BGP_OPEN_SIZE		29	/* unaligned */
79 
80 struct bgp_opt {
81 	u_int8_t bgpopt_type;
82 	u_int8_t bgpopt_len;
83 	/* variable length */
84 };
85 #define BGP_OPT_SIZE		2	/* some compilers may pad to 4 bytes */
86 
87 struct bgp_notification {
88 	u_int8_t bgpn_marker[16];
89 	u_int16_t bgpn_len;
90 	u_int8_t bgpn_type;
91 	u_int8_t bgpn_major;
92 	u_int8_t bgpn_minor;
93 	/* data should follow */
94 };
95 #define BGP_NOTIFICATION_SIZE		21	/* unaligned */
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", "Capabilities Advertisement",
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 		snprintf(buf, sizeof(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 		snprintf(buf, sizeof(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, u_int buflen)
277 {
278 	struct in_addr addr;
279 	u_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 	snprintf(buf, buflen, "%s/%d", getname((u_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, u_int buflen)
298 {
299 	struct in6_addr addr;
300 	u_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 	snprintf(buf, buflen, "%s/%d", getname6((u_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[MAXHOSTNAMELEN + 100];
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] * 2; i += 2) {
353 				printf("%s%u", i == 0 ? "" : " ",
354 					EXTRACT_16BITS(&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", EXTRACT_32BITS(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", EXTRACT_16BITS(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 = EXTRACT_32BITS(&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 = EXTRACT_16BITS(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 			i = 0;
434 			while (i < tlen) {
435 				switch (af) {
436 				case AFNUM_INET:
437 					printf(" %s", getname(p + 1 + i));
438 					i += sizeof(struct in_addr);
439 					break;
440 #ifdef INET6
441 				case AFNUM_INET6:
442 					printf(" %s", getname6(p + 1 + i));
443 					i += sizeof(struct in6_addr);
444 					break;
445 #endif
446 				default:
447 					printf(" (unknown af)");
448 					i = tlen;	/*exit loop*/
449 					break;
450 				}
451 			}
452 			printf(",");
453 		}
454 		p += 1 + tlen;
455 
456 		snpa = p[0];
457 		p++;
458 		if (snpa) {
459 			printf(" %u snpa", snpa);
460 			for (/*nothing*/; snpa > 0; snpa--) {
461 				printf("(%d bytes)", p[0]);
462 				p += p[0] + 1;
463 			}
464 			printf(",");
465 		}
466 
467 		printf(" NLRI");
468 		while (len - (p - dat) > 0) {
469 			switch (af) {
470 			case AFNUM_INET:
471 				advance = decode_prefix4(p, buf, sizeof(buf));
472 				printf(" %s", buf);
473 				break;
474 #ifdef INET6
475 			case AFNUM_INET6:
476 				advance = decode_prefix6(p, buf, sizeof(buf));
477 				printf(" %s", buf);
478 				break;
479 #endif
480 			default:
481 				printf(" (unknown af)");
482 				advance = 0;
483 				p = dat + len;
484 				break;
485 			}
486 
487 			p += advance;
488 		}
489 
490 		break;
491 
492 	case BGPTYPE_MP_UNREACH_NLRI:
493 		af = EXTRACT_16BITS(p);
494 		safi = p[2];
495 		if (safi >= 128)
496 			printf(" %s vendor specific,", af_name(af));
497 		else {
498 			printf(" %s %s,", af_name(af),
499 				bgp_attr_nlri_safi(safi));
500 		}
501 		p += 3;
502 
503 		printf(" Withdraw");
504 		while (len - (p - dat) > 0) {
505 			switch (af) {
506 			case AFNUM_INET:
507 				advance = decode_prefix4(p, buf, sizeof(buf));
508 				printf(" %s", buf);
509 				break;
510 #ifdef INET6
511 			case AFNUM_INET6:
512 				advance = decode_prefix6(p, buf, sizeof(buf));
513 				printf(" %s", buf);
514 				break;
515 #endif
516 			default:
517 				printf(" (unknown af)");
518 				advance = 0;
519 				p = dat + len;
520 				break;
521 			}
522 
523 			p += advance;
524 		}
525 		break;
526 	default:
527 		break;
528 	}
529 }
530 
531 static void
532 bgp_open_print(const u_char *dat, int length)
533 {
534 	struct bgp_open bgpo;
535 	struct bgp_opt bgpopt;
536 	int hlen;
537 	const u_char *opt;
538 	int i;
539 
540 	TCHECK2(dat[0], BGP_OPEN_SIZE);
541 	memcpy(&bgpo, dat, BGP_OPEN_SIZE);
542 	hlen = ntohs(bgpo.bgpo_len);
543 
544 	printf(": Version %d,", bgpo.bgpo_version);
545 	printf(" AS #%u,", ntohs(bgpo.bgpo_myas));
546 	printf(" Holdtime %u,", ntohs(bgpo.bgpo_holdtime));
547 	printf(" ID %s,", getname((u_char *)&bgpo.bgpo_id));
548 	printf(" Option length %u", bgpo.bgpo_optlen);
549 
550 	/* ugly! */
551 	opt = &((const struct bgp_open *)dat)->bgpo_optlen;
552 	opt++;
553 
554 	i = 0;
555 	while (i < bgpo.bgpo_optlen) {
556 		TCHECK2(opt[i], BGP_OPT_SIZE);
557 		memcpy(&bgpopt, &opt[i], BGP_OPT_SIZE);
558 		if (i + 2 + bgpopt.bgpopt_len > bgpo.bgpo_optlen) {
559 			printf(" [|opt %d %d]", bgpopt.bgpopt_len, bgpopt.bgpopt_type);
560 			break;
561 		}
562 
563 		printf(" (option %s, len=%d)", bgp_opttype(bgpopt.bgpopt_type),
564 			bgpopt.bgpopt_len);
565 		i += BGP_OPT_SIZE + bgpopt.bgpopt_len;
566 	}
567 	return;
568 trunc:
569 	printf("[|BGP]");
570 }
571 
572 static void
573 bgp_update_print(const u_char *dat, int length)
574 {
575 	struct bgp bgp;
576 	struct bgp_attr bgpa;
577 	int hlen;
578 	const u_char *p;
579 	int len;
580 	int i;
581 	int newline;
582 
583 	TCHECK2(dat[0], BGP_SIZE);
584 	memcpy(&bgp, dat, BGP_SIZE);
585 	hlen = ntohs(bgp.bgp_len);
586 	p = dat + BGP_SIZE;	/*XXX*/
587 	printf(":");
588 
589 	/* Unfeasible routes */
590 	len = EXTRACT_16BITS(p);
591 	if (len) {
592 		/*
593 		 * Without keeping state from the original NLRI message,
594 		 * it's not possible to tell if this a v4 or v6 route,
595 		 * so only try to decode it if we're not v6 enabled.
596 	         */
597 #ifdef INET6
598 		printf(" (Withdrawn routes: %d bytes)", len);
599 #else
600 		char buf[MAXHOSTNAMELEN + 100];
601 
602 		TCHECK2(p[2], len);
603  		i = 2;
604 
605 		printf(" (Withdrawn routes:");
606 
607 		while(i < 2 + len) {
608 			i += decode_prefix4(&p[i], buf, sizeof(buf));
609 			printf(" %s", buf);
610 		}
611 		printf(")\n");
612 #endif
613 	}
614 	p += 2 + len;
615 
616 	TCHECK2(p[0], 2);
617 	len = EXTRACT_16BITS(p);
618 	if (len) {
619 		/* do something more useful!*/
620 		i = 2;
621 		printf(" (Path attributes:");	/* ) */
622 		newline = 0;
623 		while (i < 2 + len) {
624 			int alen, aoff;
625 
626 			TCHECK2(p[i], sizeof(bgpa));
627 			memcpy(&bgpa, &p[i], sizeof(bgpa));
628 			alen = bgp_attr_len(&bgpa);
629 			aoff = bgp_attr_off(&bgpa);
630 
631 			if (vflag && newline)
632 				printf("\n\t\t");
633 			else
634 				printf(" ");
635 			printf("(");		/* ) */
636 			printf("%s", bgp_attr_type(bgpa.bgpa_type));
637 			if (bgpa.bgpa_flags) {
638 				printf("[%s%s%s%s",
639 					bgpa.bgpa_flags & 0x80 ? "O" : "",
640 					bgpa.bgpa_flags & 0x40 ? "T" : "",
641 					bgpa.bgpa_flags & 0x20 ? "P" : "",
642 					bgpa.bgpa_flags & 0x10 ? "E" : "");
643 				if (bgpa.bgpa_flags & 0xf)
644 					printf("+%x", bgpa.bgpa_flags & 0xf);
645 				printf("]");
646 			}
647 
648 			bgp_attr_print(&bgpa, &p[i + aoff], alen);
649 			newline = 1;
650 
651 			/* ( */
652 			printf(")");
653 
654 			i += aoff + alen;
655 		}
656 
657 		/* ( */
658 		printf(")");
659 	}
660 	p += 2 + len;
661 
662 	if (len && dat + length > p)
663 		printf("\n\t\t");
664 	if (dat + length > p) {
665 		printf("(NLRI:");	/* ) */
666 		while (dat + length > p) {
667 			char buf[MAXHOSTNAMELEN + 100];
668 			i = decode_prefix4(p, buf, sizeof(buf));
669 			printf(" %s", buf);
670 			if (i < 0)
671 				break;
672 			p += i;
673 		}
674 
675 		/* ( */
676 		printf(")");
677 	}
678 	return;
679 trunc:
680 	printf("[|BGP]");
681 }
682 
683 static void
684 bgp_notification_print(const u_char *dat, int length)
685 {
686 	struct bgp_notification bgpn;
687 	int hlen;
688 
689 	TCHECK2(dat[0], BGP_NOTIFICATION_SIZE);
690 	memcpy(&bgpn, dat, BGP_NOTIFICATION_SIZE);
691 	hlen = ntohs(bgpn.bgpn_len);
692 
693 	printf(": error %s,", bgp_notify_major(bgpn.bgpn_major));
694 	printf(" subcode %s",
695 		bgp_notify_minor(bgpn.bgpn_major, bgpn.bgpn_minor));
696 	return;
697 trunc:
698 	printf("[|BGP]");
699 }
700 
701 static void
702 bgp_header_print(const u_char *dat, int length)
703 {
704 	struct bgp bgp;
705 
706 	TCHECK2(dat[0], BGP_SIZE);
707 	memcpy(&bgp, dat, BGP_SIZE);
708 	printf("(%s", bgp_type(bgp.bgp_type));		/* ) */
709 
710 	switch (bgp.bgp_type) {
711 	case BGP_OPEN:
712 		bgp_open_print(dat, length);
713 		break;
714 	case BGP_UPDATE:
715 		bgp_update_print(dat, length);
716 		break;
717 	case BGP_NOTIFICATION:
718 		bgp_notification_print(dat, length);
719 		break;
720 	}
721 
722 	/* ( */
723 	printf(")");
724 	return;
725 trunc:
726 	printf("[|BGP]");
727 }
728 
729 void
730 bgp_print(const u_char *dat, int length)
731 {
732 	const u_char *p;
733 	const u_char *ep;
734 	const u_char *start;
735 	const u_char marker[] = {
736 		0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
737 		0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
738 	};
739 	struct bgp bgp;
740 	u_int16_t hlen;
741 	int newline;
742 
743 	ep = dat + length;
744 	if (snapend < dat + length)
745 		ep = snapend;
746 
747 	printf(": BGP");
748 
749 	p = dat;
750 	newline = 0;
751 	start = p;
752 	while (p < snapend) {
753 		if (!TTEST2(p[0], 1))
754 			break;
755 		if (p[0] != 0xff) {
756 			p++;
757 			continue;
758 		}
759 
760 		if (!TTEST2(p[0], sizeof(marker)))
761 			break;
762 		if (memcmp(p, marker, sizeof(marker)) != 0) {
763 			p++;
764 			continue;
765 		}
766 
767 		/* found BGP header */
768 		TCHECK2(p[0], BGP_SIZE);	/*XXX*/
769 		memcpy(&bgp, p, BGP_SIZE);
770 
771 		if (start != p)
772 			printf(" [|BGP]");
773 
774 		hlen = ntohs(bgp.bgp_len);
775 		if (vflag && newline)
776 			printf("\n\t");
777 		else
778 			printf(" ");
779 		if (TTEST2(p[0], hlen)) {
780 			bgp_header_print(p, hlen);
781 			newline = 1;
782 			p += hlen;
783 			start = p;
784 		} else {
785 			printf("[|BGP %s]", bgp_type(bgp.bgp_type));
786 			break;
787 		}
788 	}
789 
790 	return;
791 
792 trunc:
793 	printf(" [|BGP]");
794 }
795