xref: /freebsd/contrib/tcpdump/print-bgp.c (revision 1b6c76a2fe091c74f08427e6c870851025a9cf67)
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 1.21 2000/12/05 05:48:35 guy 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 
79 struct bgp_opt {
80 	u_int8_t bgpopt_type;
81 	u_int8_t bgpopt_len;
82 	/* variable length */
83 };
84 
85 struct bgp_notification {
86 	u_int8_t bgpn_marker[16];
87 	u_int16_t bgpn_len;
88 	u_int8_t bgpn_type;
89 	u_int8_t bgpn_major;
90 	u_int8_t bgpn_minor;
91 	/* data should follow */
92 };
93 
94 struct bgp_attr {
95 	u_int8_t bgpa_flags;
96 	u_int8_t bgpa_type;
97 	union {
98 		u_int8_t len;
99 		u_int16_t elen;
100 	} bgpa_len;
101 #define bgp_attr_len(p) \
102 	(((p)->bgpa_flags & 0x10) ? \
103 		ntohs((p)->bgpa_len.elen) : (p)->bgpa_len.len)
104 #define bgp_attr_off(p) \
105 	(((p)->bgpa_flags & 0x10) ? 4 : 3)
106 };
107 
108 #define BGPTYPE_ORIGIN			1
109 #define BGPTYPE_AS_PATH			2
110 #define BGPTYPE_NEXT_HOP		3
111 #define BGPTYPE_MULTI_EXIT_DISC		4
112 #define BGPTYPE_LOCAL_PREF		5
113 #define BGPTYPE_ATOMIC_AGGREGATE	6
114 #define BGPTYPE_AGGREGATOR		7
115 #define	BGPTYPE_COMMUNITIES		8	/* RFC1997 */
116 #define	BGPTYPE_ORIGINATOR_ID		9	/* RFC1998 */
117 #define	BGPTYPE_CLUSTER_LIST		10	/* RFC1998 */
118 #define	BGPTYPE_DPA			11	/* work in progress */
119 #define	BGPTYPE_ADVERTISERS		12	/* RFC1863 */
120 #define	BGPTYPE_RCID_PATH		13	/* RFC1863 */
121 #define BGPTYPE_MP_REACH_NLRI		14	/* RFC2283 */
122 #define BGPTYPE_MP_UNREACH_NLRI		15	/* RFC2283 */
123 
124 
125 static const char *bgptype[] = {
126 	NULL, "OPEN", "UPDATE", "NOTIFICATION", "KEEPALIVE",
127 };
128 #define bgp_type(x) num_or_str(bgptype, sizeof(bgptype)/sizeof(bgptype[0]), (x))
129 
130 static const char *bgpopt_type[] = {
131 	NULL, "Authentication Information",
132 };
133 #define bgp_opttype(x) \
134 	num_or_str(bgpopt_type, sizeof(bgpopt_type)/sizeof(bgpopt_type[0]), (x))
135 
136 static const char *bgpnotify_major[] = {
137 	NULL, "Message Header Error",
138 	"OPEN Message Error", "UPDATE Message Error",
139 	"Hold Timer Expired", "Finite State Machine Error",
140 	"Cease",
141 };
142 #define bgp_notify_major(x) \
143 	num_or_str(bgpnotify_major, \
144 		sizeof(bgpnotify_major)/sizeof(bgpnotify_major[0]), (x))
145 
146 static const char *bgpnotify_minor_1[] = {
147 	NULL, "Connection Not Synchronized",
148 	"Bad Message Length", "Bad Message Type",
149 };
150 
151 static const char *bgpnotify_minor_2[] = {
152 	NULL, "Unsupported Version Number",
153 	"Bad Peer AS", "Bad BGP Identifier",
154 	"Unsupported Optional Parameter", "Authentication Failure",
155 	"Unacceptable Hold Time",
156 };
157 
158 static const char *bgpnotify_minor_3[] = {
159 	NULL, "Malformed Attribute List",
160 	"Unrecognized Well-known Attribute", "Missing Well-known Attribute",
161 	"Attribute Flags Error", "Attribute Length Error",
162 	"Invalid ORIGIN Attribute", "AS Routing Loop",
163 	"Invalid NEXT_HOP Attribute", "Optional Attribute Error",
164 	"Invalid Network Field", "Malformed AS_PATH",
165 };
166 
167 static const char **bgpnotify_minor[] = {
168 	NULL, bgpnotify_minor_1, bgpnotify_minor_2, bgpnotify_minor_3,
169 };
170 static const int bgpnotify_minor_siz[] = {
171 	0, sizeof(bgpnotify_minor_1)/sizeof(bgpnotify_minor_1[0]),
172 	sizeof(bgpnotify_minor_2)/sizeof(bgpnotify_minor_2[0]),
173 	sizeof(bgpnotify_minor_3)/sizeof(bgpnotify_minor_3[0]),
174 };
175 
176 static const char *bgpattr_origin[] = {
177 	"IGP", "EGP", "INCOMPLETE",
178 };
179 #define bgp_attr_origin(x) \
180 	num_or_str(bgpattr_origin, \
181 		sizeof(bgpattr_origin)/sizeof(bgpattr_origin[0]), (x))
182 
183 static const char *bgpattr_type[] = {
184 	NULL, "ORIGIN", "AS_PATH", "NEXT_HOP",
185 	"MULTI_EXIT_DISC", "LOCAL_PREF", "ATOMIC_AGGREGATE", "AGGREGATOR",
186 	"COMMUNITIES", "ORIGINATOR_ID", "CLUSTER_LIST", "DPA",
187 	"ADVERTISERS", "RCID_PATH", "MP_REACH_NLRI", "MP_UNREACH_NLRI",
188 };
189 #define bgp_attr_type(x) \
190 	num_or_str(bgpattr_type, \
191 		sizeof(bgpattr_type)/sizeof(bgpattr_type[0]), (x))
192 
193 /* Subsequent address family identifier, RFC2283 section 7 */
194 static const char *bgpattr_nlri_safi[] = {
195     "Reserved", "Unicast", "Multicast", "Unicast+Multicast",
196 };
197 #define bgp_attr_nlri_safi(x) \
198 	num_or_str(bgpattr_nlri_safi, \
199 		sizeof(bgpattr_nlri_safi)/sizeof(bgpattr_nlri_safi[0]), (x))
200 
201 /* well-known community */
202 #define BGP_COMMUNITY_NO_EXPORT			0xffffff01
203 #define BGP_COMMUNITY_NO_ADVERT			0xffffff02
204 #define BGP_COMMUNITY_NO_EXPORT_SUBCONFED	0xffffff03
205 
206 /* RFC1700 address family numbers */
207 #define AFNUM_INET	1
208 #define AFNUM_INET6	2
209 #define AFNUM_NSAP	3
210 #define AFNUM_HDLC	4
211 #define AFNUM_BBN1822	5
212 #define AFNUM_802	6
213 #define AFNUM_E163	7
214 #define AFNUM_E164	8
215 #define AFNUM_F69	9
216 #define AFNUM_X121	10
217 #define AFNUM_IPX	11
218 #define AFNUM_ATALK	12
219 #define AFNUM_DECNET	13
220 #define AFNUM_BANYAN	14
221 #define AFNUM_E164NSAP	15
222 
223 static const char *afnumber[] = {
224 	"Reserved", "IPv4", "IPv6", "NSAP", "HDLC",
225 	"BBN 1822", "802", "E.163", "E.164", "F.69",
226 	"X.121", "IPX", "Appletalk", "Decnet IV", "Banyan Vines",
227 	"E.164 with NSAP subaddress",
228 };
229 #define af_name(x) \
230 	(((x) == 65535) ? afnumber[0] : \
231 		num_or_str(afnumber, \
232 			sizeof(afnumber)/sizeof(afnumber[0]), (x)))
233 
234 
235 static const char *
236 num_or_str(const char **table, size_t siz, int value)
237 {
238 	static char buf[20];
239 	if (value < 0 || siz <= value || table[value] == NULL) {
240 		snprintf(buf, sizeof(buf), "#%d", value);
241 		return buf;
242 	} else
243 		return table[value];
244 }
245 
246 static const char *
247 bgp_notify_minor(int major, int minor)
248 {
249 	static const char **table;
250 	int siz;
251 	static char buf[20];
252 	const char *p;
253 
254 	if (0 <= major
255 	 && major < sizeof(bgpnotify_minor)/sizeof(bgpnotify_minor[0])
256 	 && bgpnotify_minor[major]) {
257 		table = bgpnotify_minor[major];
258 		siz = bgpnotify_minor_siz[major];
259 		if (0 <= minor && minor < siz && table[minor])
260 			p = table[minor];
261 		else
262 			p = NULL;
263 	} else
264 		p = NULL;
265 	if (p == NULL) {
266 		snprintf(buf, sizeof(buf), "#%d", minor);
267 		return buf;
268 	} else
269 		return p;
270 }
271 
272 static int
273 decode_prefix4(const u_char *pd, char *buf, int buflen)
274 {
275 	struct in_addr addr;
276 	int plen;
277 
278 	plen = pd[0];
279 	if (plen < 0 || 32 < plen)
280 		return -1;
281 
282 	memset(&addr, 0, sizeof(addr));
283 	memcpy(&addr, &pd[1], (plen + 7) / 8);
284 	if (plen % 8) {
285 		((u_char *)&addr)[(plen + 7) / 8 - 1] &=
286 			((0xff00 >> (plen % 8)) & 0xff);
287 	}
288 	snprintf(buf, buflen, "%s/%d", getname((u_char *)&addr), plen);
289 	return 1 + (plen + 7) / 8;
290 }
291 
292 #ifdef INET6
293 static int
294 decode_prefix6(const u_char *pd, char *buf, int buflen)
295 {
296 	struct in6_addr addr;
297 	int plen;
298 
299 	plen = pd[0];
300 	if (plen < 0 || 128 < plen)
301 		return -1;
302 
303 	memset(&addr, 0, sizeof(addr));
304 	memcpy(&addr, &pd[1], (plen + 7) / 8);
305 	if (plen % 8) {
306 		addr.s6_addr[(plen + 7) / 8 - 1] &=
307 			((0xff00 >> (plen % 8)) & 0xff);
308 	}
309 	snprintf(buf, buflen, "%s/%d", getname6((char *)&addr), plen);
310 	return 1 + (plen + 7) / 8;
311 }
312 #endif
313 
314 static void
315 bgp_attr_print(const struct bgp_attr *attr, const u_char *dat, int len)
316 {
317 	int i;
318 	u_int16_t af;
319 	u_int8_t safi, snpa;
320 	int advance;
321 	int tlen;
322 	const u_char *p;
323 	char buf[MAXHOSTNAMELEN + 100];
324 
325 	p = dat;
326 
327 	switch (attr->bgpa_type) {
328 	case BGPTYPE_ORIGIN:
329 		if (len != 1)
330 			printf(" invalid len");
331 		else
332 			printf(" %s", bgp_attr_origin(p[0]));
333 		break;
334 	case BGPTYPE_AS_PATH:
335 		if (len % 2) {
336 			printf(" invalid len");
337 			break;
338 		}
339 		while (p < dat + len) {
340 			/*
341 			 * under RFC1965, p[0] means:
342 			 * 1: AS_SET 2: AS_SEQUENCE
343 			 * 3: AS_CONFED_SET 4: AS_CONFED_SEQUENCE
344 			 */
345 			printf(" ");
346 			if (p[0] == 3 || p[0] == 4)
347 				printf("confed");
348 			printf("%s", (p[0] & 1) ? "{" : "");
349 			for (i = 0; i < p[1]; i += 2) {
350 				printf("%s%u", i == 0 ? "" : " ",
351 					ntohs(*(u_int16_t *)&p[2 + i]));
352 			}
353 			printf("%s", (p[0] & 1) ? "}" : "");
354 			p += 2 + p[1] * 2;
355 		}
356 		break;
357 	case BGPTYPE_NEXT_HOP:
358 		if (len != 4)
359 			printf(" invalid len");
360 		else
361 			printf(" %s", getname(p));
362 		break;
363 	case BGPTYPE_MULTI_EXIT_DISC:
364 	case BGPTYPE_LOCAL_PREF:
365 		if (len != 4)
366 			printf(" invalid len");
367 		else
368 			printf(" %u", (u_int32_t)ntohl(*(u_int32_t *)p));
369 		break;
370 	case BGPTYPE_ATOMIC_AGGREGATE:
371 		if (len != 0)
372 			printf(" invalid len");
373 		break;
374 	case BGPTYPE_AGGREGATOR:
375 		if (len != 6) {
376 			printf(" invalid len");
377 			break;
378 		}
379 		printf(" AS #%u, origin %s", ntohs(*(u_int16_t *)p),
380 			getname(p + 2));
381 		break;
382 	case BGPTYPE_COMMUNITIES:
383 		if (len % 4) {
384 			printf(" invalid len");
385 			break;
386 		}
387 		for (i = 0; i < len; i += 4) {
388 			u_int32_t comm;
389 			comm = (u_int32_t)ntohl(*(u_int32_t *)&p[i]);
390 			switch (comm) {
391 			case BGP_COMMUNITY_NO_EXPORT:
392 				printf(" NO_EXPORT");
393 				break;
394 			case BGP_COMMUNITY_NO_ADVERT:
395 				printf(" NO_ADVERTISE");
396 				break;
397 			case BGP_COMMUNITY_NO_EXPORT_SUBCONFED:
398 				printf(" NO_EXPORT_SUBCONFED");
399 				break;
400 			default:
401 				printf(" (AS #%d value 0x%04x)",
402 					(comm >> 16) & 0xffff, comm & 0xffff);
403 				break;
404 			}
405 		}
406 		break;
407 	case BGPTYPE_MP_REACH_NLRI:
408 		af = ntohs(*(u_int16_t *)p);
409 		safi = p[2];
410 		if (safi >= 128)
411 			printf(" %s vendor specific,", af_name(af));
412 		else {
413 			printf(" %s %s,", af_name(af),
414 				bgp_attr_nlri_safi(safi));
415 		}
416 		p += 3;
417 
418 		if (af == AFNUM_INET)
419 			;
420 #ifdef INET6
421 		else if (af == AFNUM_INET6)
422 			;
423 #endif
424 		else
425 			break;
426 
427 		tlen = p[0];
428 		if (tlen) {
429 			printf(" nexthop");
430 			i = 0;
431 			while (i < tlen) {
432 				switch (af) {
433 				case AFNUM_INET:
434 					printf(" %s", getname(p + 1 + i));
435 					i += sizeof(struct in_addr);
436 					break;
437 #ifdef INET6
438 				case AFNUM_INET6:
439 					printf(" %s", getname6(p + 1 + i));
440 					i += sizeof(struct in6_addr);
441 					break;
442 #endif
443 				default:
444 					printf(" (unknown af)");
445 					i = tlen;	/*exit loop*/
446 					break;
447 				}
448 			}
449 			printf(",");
450 		}
451 		p += 1 + tlen;
452 
453 		snpa = p[0];
454 		p++;
455 		if (snpa) {
456 			printf(" %u snpa", snpa);
457 			for (/*nothing*/; snpa > 0; snpa--) {
458 				printf("(%d bytes)", p[0]);
459 				p += p[0] + 1;
460 			}
461 			printf(",");
462 		}
463 
464 		printf(" NLRI");
465 		while (len - (p - dat) > 0) {
466 			switch (af) {
467 			case AFNUM_INET:
468 				advance = decode_prefix4(p, buf, sizeof(buf));
469 				printf(" %s", buf);
470 				break;
471 #ifdef INET6
472 			case AFNUM_INET6:
473 				advance = decode_prefix6(p, buf, sizeof(buf));
474 				printf(" %s", buf);
475 				break;
476 #endif
477 			default:
478 				printf(" (unknown af)");
479 				advance = 0;
480 				p = dat + len;
481 				break;
482 			}
483 
484 			p += advance;
485 		}
486 
487 		break;
488 
489 	case BGPTYPE_MP_UNREACH_NLRI:
490 		af = ntohs(*(u_int16_t *)p);
491 		safi = p[2];
492 		if (safi >= 128)
493 			printf(" %s vendor specific,", af_name(af));
494 		else {
495 			printf(" %s %s,", af_name(af),
496 				bgp_attr_nlri_safi(safi));
497 		}
498 		p += 3;
499 
500 		printf(" Withdraw");
501 		while (len - (p - dat) > 0) {
502 			switch (af) {
503 			case AFNUM_INET:
504 				advance = decode_prefix4(p, buf, sizeof(buf));
505 				printf(" %s", buf);
506 				break;
507 #ifdef INET6
508 			case AFNUM_INET6:
509 				advance = decode_prefix6(p, buf, sizeof(buf));
510 				printf(" %s", buf);
511 				break;
512 #endif
513 			default:
514 				printf(" (unknown af)");
515 				advance = 0;
516 				p = dat + len;
517 				break;
518 			}
519 
520 			p += advance;
521 		}
522 		break;
523 	default:
524 		break;
525 	}
526 }
527 
528 static void
529 bgp_open_print(const u_char *dat, int length)
530 {
531 	struct bgp_open bgpo;
532 	struct bgp_opt bgpopt;
533 	int hlen;
534 	const u_char *opt;
535 	int i;
536 
537 	TCHECK2(dat[0], sizeof(bgpo));
538 	memcpy(&bgpo, dat, sizeof(bgpo));
539 	hlen = ntohs(bgpo.bgpo_len);
540 
541 	printf(": Version %d,", bgpo.bgpo_version);
542 	printf(" AS #%u,", ntohs(bgpo.bgpo_myas));
543 	printf(" Holdtime %u,", ntohs(bgpo.bgpo_holdtime));
544 	printf(" ID %s,", getname((u_char *)&bgpo.bgpo_id));
545 	printf(" Option length %u", bgpo.bgpo_optlen);
546 
547 	/* ugly! */
548 	opt = &((struct bgp_open *)dat)->bgpo_optlen;
549 	opt++;
550 
551 	for (i = 0; i < bgpo.bgpo_optlen; i++) {
552 		memcpy(&bgpopt, &opt[i], sizeof(bgpopt));
553 		if (i + 2 + bgpopt.bgpopt_len > bgpo.bgpo_optlen) {
554 			printf(" [|opt %d %d]", bgpopt.bgpopt_len, bgpopt.bgpopt_type);
555 			break;
556 		}
557 
558 		printf(" (option %s, len=%d)", bgp_opttype(bgpopt.bgpopt_type),
559 			bgpopt.bgpopt_len);
560 		i += sizeof(bgpopt) + bgpopt.bgpopt_len;
561 	}
562 	return;
563 trunc:
564 	printf("[|BGP]");
565 }
566 
567 static void
568 bgp_update_print(const u_char *dat, int length)
569 {
570 	struct bgp bgp;
571 	struct bgp_attr bgpa;
572 	int hlen;
573 	const u_char *p;
574 	int len;
575 	int i;
576 	int newline;
577 
578 	TCHECK2(dat[0], sizeof(bgp));
579 	memcpy(&bgp, dat, sizeof(bgp));
580 	hlen = ntohs(bgp.bgp_len);
581 	p = dat + BGP_SIZE;	/*XXX*/
582 	printf(":");
583 
584 	/* Unfeasible routes */
585 	len = EXTRACT_16BITS(p);
586 	if (len) {
587 		/*  Without keeping state from the original NLRI message,
588 		 *  it's not possible to tell if this a v4 or v6 route,
589 		 *  so only try to decode it if we're not v6 enabled.
590 	         */
591 #ifdef INET6
592 		printf(" (Withdrawn routes: %d bytes)", len);
593 #else
594 		char buf[MAXHOSTNAMELEN + 100];
595 
596 		TCHECK2(p[2], len);
597  		i = 2;
598 
599 		printf(" (Withdrawn routes:");
600 
601 		while(i < 2 + len) {
602 			i += decode_prefix4(&p[i], buf, sizeof(buf));
603 			printf(" %s", buf);
604 		}
605 		printf(")\n");
606 #endif
607 	}
608 	p += 2 + len;
609 
610 	TCHECK2(p[0], 2);
611 	len = EXTRACT_16BITS(p);
612 	if (len) {
613 		/* do something more useful!*/
614 		i = 2;
615 		printf(" (Path attributes:");	/* ) */
616 		newline = 0;
617 		while (i < 2 + len) {
618 			int alen, aoff;
619 
620 			TCHECK2(p[i], sizeof(bgpa));
621 			memcpy(&bgpa, &p[i], sizeof(bgpa));
622 			alen = bgp_attr_len(&bgpa);
623 			aoff = bgp_attr_off(&bgpa);
624 
625 			if (vflag && newline)
626 				printf("\n\t\t");
627 			else
628 				printf(" ");
629 			printf("(");		/* ) */
630 			printf("%s", bgp_attr_type(bgpa.bgpa_type));
631 			if (bgpa.bgpa_flags) {
632 				printf("[%s%s%s%s",
633 					bgpa.bgpa_flags & 0x80 ? "O" : "",
634 					bgpa.bgpa_flags & 0x40 ? "T" : "",
635 					bgpa.bgpa_flags & 0x20 ? "P" : "",
636 					bgpa.bgpa_flags & 0x10 ? "E" : "");
637 				if (bgpa.bgpa_flags & 0xf)
638 					printf("+%x", bgpa.bgpa_flags & 0xf);
639 				printf("]");
640 			}
641 
642 			bgp_attr_print(&bgpa, &p[i + aoff], alen);
643 			newline = 1;
644 
645 			/* ( */
646 			printf(")");
647 
648 			i += aoff + alen;
649 		}
650 
651 		/* ( */
652 		printf(")");
653 	}
654 	p += 2 + len;
655 
656 	if (len && dat + length > p)
657 		printf("\n\t\t");
658 	if (dat + length > p) {
659 		printf("(NLRI:");	/* ) */
660 		while (dat + length > p) {
661 			char buf[MAXHOSTNAMELEN + 100];
662 			i = decode_prefix4(p, buf, sizeof(buf));
663 			printf(" %s", buf);
664 			if (i < 0)
665 				break;
666 			p += i;
667 		}
668 
669 		/* ( */
670 		printf(")");
671 	}
672 	return;
673 trunc:
674 	printf("[|BGP]");
675 }
676 
677 static void
678 bgp_notification_print(const u_char *dat, int length)
679 {
680 	struct bgp_notification bgpn;
681 	int hlen;
682 
683 	TCHECK2(dat[0], sizeof(bgpn));
684 	memcpy(&bgpn, dat, sizeof(bgpn));
685 	hlen = ntohs(bgpn.bgpn_len);
686 
687 	printf(": error %s,", bgp_notify_major(bgpn.bgpn_major));
688 	printf(" subcode %s",
689 		bgp_notify_minor(bgpn.bgpn_major, bgpn.bgpn_minor));
690 	return;
691 trunc:
692 	printf("[|BGP]");
693 }
694 
695 static void
696 bgp_header_print(const u_char *dat, int length)
697 {
698 	struct bgp bgp;
699 
700 	TCHECK2(dat[0], sizeof(bgp));
701 	memcpy(&bgp, dat, sizeof(bgp));
702 	printf("(%s", bgp_type(bgp.bgp_type));		/* ) */
703 
704 	switch (bgp.bgp_type) {
705 	case BGP_OPEN:
706 		bgp_open_print(dat, length);
707 		break;
708 	case BGP_UPDATE:
709 		bgp_update_print(dat, length);
710 		break;
711 	case BGP_NOTIFICATION:
712 		bgp_notification_print(dat, length);
713 		break;
714 	}
715 
716 	/* ( */
717 	printf(")");
718 	return;
719 trunc:
720 	printf("[|BGP]");
721 }
722 
723 void
724 bgp_print(const u_char *dat, int length)
725 {
726 	const u_char *p;
727 	const u_char *ep;
728 	const u_char *start;
729 	const u_char marker[] = {
730 		0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
731 		0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
732 	};
733 	struct bgp bgp;
734 	u_int16_t hlen;
735 	int newline;
736 
737 	ep = dat + length;
738 	if (snapend < dat + length)
739 		ep = snapend;
740 
741 	printf(": BGP");
742 
743 	p = dat;
744 	newline = 0;
745 	start = p;
746 	while (p < snapend) {
747 		if (!TTEST2(p[0], 1))
748 			break;
749 		if (p[0] != 0xff) {
750 			p++;
751 			continue;
752 		}
753 
754 		if (!TTEST2(p[0], sizeof(marker)))
755 			break;
756 		if (memcmp(p, marker, sizeof(marker)) != 0) {
757 			p++;
758 			continue;
759 		}
760 
761 		/* found BGP header */
762 		TCHECK2(p[0], sizeof(bgp));	/*XXX*/
763 		memcpy(&bgp, p, sizeof(bgp));
764 
765 		if (start != p)
766 			printf(" [|BGP]");
767 
768 		hlen = ntohs(bgp.bgp_len);
769 		if (vflag && newline)
770 			printf("\n\t");
771 		else
772 			printf(" ");
773 		if (TTEST2(p[0], hlen)) {
774 			bgp_header_print(p, hlen);
775 			newline = 1;
776 			p += hlen;
777 			start = p;
778 		} else {
779 			printf("[|BGP %s]", bgp_type(bgp.bgp_type));
780 			break;
781 		}
782 	}
783 
784 	return;
785 
786 trunc:
787 	printf(" [|BGP]");
788 }
789