GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: usr.sbin/tcpdump/print-tcp.c Lines: 0 312 0.0 %
Date: 2017-11-13 Branches: 0 345 0.0 %

Line Branch Exec Source
1
/*	$OpenBSD: print-tcp.c,v 1.37 2016/11/16 13:47:27 reyk Exp $	*/
2
3
/*
4
 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
5
 *	The Regents of the University of California.  All rights reserved.
6
 *
7
 * Redistribution and use in source and binary forms, with or without
8
 * modification, are permitted provided that: (1) source code distributions
9
 * retain the above copyright notice and this paragraph in its entirety, (2)
10
 * distributions including binary code include the above copyright notice and
11
 * this paragraph in its entirety in the documentation or other materials
12
 * provided with the distribution, and (3) all advertising materials mentioning
13
 * features or use of this software display the following acknowledgement:
14
 * ``This product includes software developed by the University of California,
15
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
16
 * the University nor the names of its contributors may be used to endorse
17
 * or promote products derived from this software without specific prior
18
 * written permission.
19
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
20
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
21
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
22
 */
23
24
#include <sys/time.h>
25
#include <sys/socket.h>
26
27
#include <netinet/in.h>
28
#include <netinet/ip.h>
29
#include <netinet/ip_var.h>
30
#include <netinet/tcp.h>
31
#include <net/if.h>
32
#include <net/pfvar.h>
33
34
#include <rpc/rpc.h>
35
36
#include <stdio.h>
37
#include <stdlib.h>
38
#include <string.h>
39
#include <unistd.h>
40
41
#ifdef INET6
42
#include <netinet/ip6.h>
43
#endif
44
45
#include "interface.h"
46
#include "addrtoname.h"
47
#include "extract.h"
48
49
#include "nfs.h"
50
51
static void print_tcp_rst_data(const u_char *sp, u_int length);
52
53
#define MAX_RST_DATA_LEN	30
54
55
/* Compatibility */
56
#ifndef TCPOPT_WSCALE
57
#define	TCPOPT_WSCALE		3	/* window scale factor (rfc1072) */
58
#endif
59
#ifndef TCPOPT_SACKOK
60
#define	TCPOPT_SACKOK		4	/* selective ack ok (rfc2018) */
61
#endif
62
#ifndef TCPOPT_SACK
63
#define	TCPOPT_SACK		5	/* selective ack (rfc2018) */
64
#endif
65
#ifndef TCPOLEN_SACK
66
#define TCPOLEN_SACK		8	/* length of a SACK block */
67
#endif
68
#ifndef TCPOPT_ECHO
69
#define	TCPOPT_ECHO		6	/* echo (rfc1072) */
70
#endif
71
#ifndef TCPOPT_ECHOREPLY
72
#define	TCPOPT_ECHOREPLY	7	/* echo (rfc1072) */
73
#endif
74
#ifndef TCPOPT_TIMESTAMP
75
#define TCPOPT_TIMESTAMP	8	/* timestamps (rfc1323) */
76
#endif
77
#ifndef TCPOPT_CC
78
#define TCPOPT_CC		11	/* T/TCP CC options (rfc1644) */
79
#endif
80
#ifndef TCPOPT_CCNEW
81
#define TCPOPT_CCNEW		12	/* T/TCP CC options (rfc1644) */
82
#endif
83
#ifndef TCPOPT_CCECHO
84
#define TCPOPT_CCECHO		13	/* T/TCP CC options (rfc1644) */
85
#endif
86
87
/* Definitions required for ECN
88
   for use if the OS running tcpdump does not have ECN */
89
#ifndef TH_ECNECHO
90
#define TH_ECNECHO		0x40	/* ECN Echo in tcp header */
91
#endif
92
#ifndef TH_CWR
93
#define TH_CWR			0x80	/* ECN Cwnd Reduced in tcp header*/
94
#endif
95
96
struct tha {
97
#ifndef INET6
98
	struct in_addr src;
99
	struct in_addr dst;
100
#else
101
	struct in6_addr src;
102
	struct in6_addr dst;
103
#endif /*INET6*/
104
	u_int port;
105
};
106
107
struct tcp_seq_hash {
108
	struct tcp_seq_hash *nxt;
109
	struct tha addr;
110
	tcp_seq seq;
111
	tcp_seq ack;
112
};
113
114
#define TSEQ_HASHSIZE 919
115
116
/* These tcp optinos do not have the size octet */
117
#define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
118
119
static struct tcp_seq_hash tcp_seq_hash[TSEQ_HASHSIZE];
120
121
#ifndef BGP_PORT
122
#define BGP_PORT        179
123
#endif
124
#define NETBIOS_SSN_PORT 139
125
126
/* OpenFlow TCP ports. */
127
#define OLD_OFP_PORT	6633
128
#define OFP_PORT	6653
129
130
static int tcp_cksum(const struct ip *ip, const struct tcphdr *tp, int len)
131
{
132
	union phu {
133
		struct phdr {
134
			u_int32_t src;
135
			u_int32_t dst;
136
			u_char mbz;
137
			u_char proto;
138
			u_int16_t len;
139
		} ph;
140
		u_int16_t pa[6];
141
	} phu;
142
	const u_int16_t *sp;
143
	u_int32_t sum;
144
145
	/* pseudo-header.. */
146
	phu.ph.len = htons((u_int16_t)len);
147
	phu.ph.mbz = 0;
148
	phu.ph.proto = IPPROTO_TCP;
149
	memcpy(&phu.ph.src, &ip->ip_src.s_addr, sizeof(u_int32_t));
150
	memcpy(&phu.ph.dst, &ip->ip_dst.s_addr, sizeof(u_int32_t));
151
152
	sp = &phu.pa[0];
153
	sum = sp[0]+sp[1]+sp[2]+sp[3]+sp[4]+sp[5];
154
155
	return in_cksum((u_short *)tp, len, sum);
156
}
157
158
#ifdef INET6
159
static int tcp6_cksum(const struct ip6_hdr *ip6, const struct tcphdr *tp,
160
		      u_int len)
161
{
162
	union {
163
		struct {
164
			struct in6_addr ph_src;
165
			struct in6_addr ph_dst;
166
			u_int32_t       ph_len;
167
			u_int8_t        ph_zero[3];
168
			u_int8_t        ph_nxt;
169
		} ph;
170
		u_int16_t pa[20];
171
	} phu;
172
	size_t i;
173
	u_int32_t sum = 0;
174
175
	/* pseudo-header */
176
	memset(&phu, 0, sizeof(phu));
177
	phu.ph.ph_src = ip6->ip6_src;
178
	phu.ph.ph_dst = ip6->ip6_dst;
179
	phu.ph.ph_len = htonl(len);
180
	phu.ph.ph_nxt = IPPROTO_TCP;
181
182
	for (i = 0; i < sizeof(phu.pa) / sizeof(phu.pa[0]); i++)
183
		sum += phu.pa[i];
184
185
	return in_cksum((u_short *)tp, len, sum);
186
}
187
#endif
188
189
190
void
191
tcp_print(const u_char *bp, u_int length, const u_char *bp2)
192
{
193
	const struct tcphdr *tp;
194
	const struct ip *ip;
195
	u_char flags;
196
	int hlen;
197
	char ch;
198
	struct tcp_seq_hash *th = NULL;
199
	int rev = 0;
200
	u_int16_t sport, dport, win, urp;
201
	tcp_seq seq, ack;
202
#ifdef INET6
203
	const struct ip6_hdr *ip6;
204
#endif
205
206
	tp = (struct tcphdr *)bp;
207
	switch (((struct ip *)bp2)->ip_v) {
208
	case 4:
209
		ip = (struct ip *)bp2;
210
#ifdef INET6
211
		ip6 = NULL;
212
#endif
213
		break;
214
#ifdef INET6
215
	case 6:
216
		ip = NULL;
217
		ip6 = (struct ip6_hdr *)bp2;
218
		break;
219
#endif
220
	default:
221
		(void)printf("invalid ip version");
222
		return;
223
	}
224
225
	ch = '\0';
226
	if (length < sizeof(*tp)) {
227
		(void)printf("truncated-tcp %u", length);
228
		return;
229
	}
230
231
	if (!TTEST(tp->th_dport)) {
232
#ifdef INET6
233
		if (ip6) {
234
			(void)printf("%s > %s: [|tcp]",
235
				ip6addr_string(&ip6->ip6_src),
236
				ip6addr_string(&ip6->ip6_dst));
237
		} else
238
#endif /*INET6*/
239
		{
240
			(void)printf("%s > %s: [|tcp]",
241
				ipaddr_string(&ip->ip_src),
242
				ipaddr_string(&ip->ip_dst));
243
		}
244
		return;
245
	}
246
247
	sport = ntohs(tp->th_sport);
248
	dport = ntohs(tp->th_dport);
249
250
#ifdef INET6
251
	if (ip6) {
252
		if (ip6->ip6_nxt == IPPROTO_TCP) {
253
			(void)printf("%s.%s > %s.%s: ",
254
				ip6addr_string(&ip6->ip6_src),
255
				tcpport_string(sport),
256
				ip6addr_string(&ip6->ip6_dst),
257
				tcpport_string(dport));
258
		} else {
259
			(void)printf("%s > %s: ",
260
				tcpport_string(sport), tcpport_string(dport));
261
		}
262
	} else
263
#endif /*INET6*/
264
	{
265
		if (ip->ip_p == IPPROTO_TCP) {
266
			(void)printf("%s.%s > %s.%s: ",
267
				ipaddr_string(&ip->ip_src),
268
				tcpport_string(sport),
269
				ipaddr_string(&ip->ip_dst),
270
				tcpport_string(dport));
271
		} else {
272
			(void)printf("%s > %s: ",
273
				tcpport_string(sport), tcpport_string(dport));
274
		}
275
	}
276
277
	if (!qflag && TTEST(tp->th_seq) && !TTEST(tp->th_ack))
278
		(void)printf("%u ", ntohl(tp->th_seq));
279
280
	TCHECK(*tp);
281
	seq = ntohl(tp->th_seq);
282
	ack = ntohl(tp->th_ack);
283
	win = ntohs(tp->th_win);
284
	urp = ntohs(tp->th_urp);
285
	hlen = tp->th_off * 4;
286
287
	if (qflag) {
288
		(void)printf("tcp %d", length - tp->th_off * 4);
289
		return;
290
	} else if (packettype != PT_TCP) {
291
292
		/*
293
		 * If data present and NFS port used, assume NFS.
294
		 * Pass offset of data plus 4 bytes for RPC TCP msg length
295
		 * to NFS print routines.
296
		 */
297
		u_int len = length - hlen;
298
		if ((u_char *)tp + 4 + sizeof(struct rpc_msg) <= snapend &&
299
		    dport == NFS_PORT) {
300
			nfsreq_print((u_char *)tp + hlen + 4, len, bp2);
301
			return;
302
		} else if ((u_char *)tp + 4 +
303
		    sizeof(struct rpc_msg) <= snapend && sport == NFS_PORT) {
304
			nfsreply_print((u_char *)tp + hlen + 4, len, bp2);
305
			return;
306
		}
307
	}
308
	if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH|
309
				      TH_ECNECHO|TH_CWR)) {
310
		if (flags & TH_SYN)
311
			putchar('S');
312
		if (flags & TH_FIN)
313
			putchar('F');
314
		if (flags & TH_RST)
315
			putchar('R');
316
		if (flags & TH_PUSH)
317
			putchar('P');
318
		if (flags & TH_CWR)
319
			putchar('W');	/* congestion _W_indow reduced (ECN) */
320
		if (flags & TH_ECNECHO)
321
			putchar('E');	/* ecn _E_cho sent (ECN) */
322
	} else
323
		putchar('.');
324
325
	if (!Sflag && (flags & TH_ACK)) {
326
		struct tha tha;
327
		/*
328
		 * Find (or record) the initial sequence numbers for
329
		 * this conversation.  (we pick an arbitrary
330
		 * collating order so there's only one entry for
331
		 * both directions).
332
		 */
333
#ifdef INET6
334
		bzero(&tha, sizeof(tha));
335
		rev = 0;
336
		if (ip6) {
337
			if (sport > dport) {
338
				rev = 1;
339
			} else if (sport == dport) {
340
			    int i;
341
342
			    for (i = 0; i < 4; i++) {
343
				if (((u_int32_t *)(&ip6->ip6_src))[i] >
344
				    ((u_int32_t *)(&ip6->ip6_dst))[i]) {
345
					rev = 1;
346
					break;
347
				}
348
			    }
349
			}
350
			if (rev) {
351
				tha.src = ip6->ip6_dst;
352
				tha.dst = ip6->ip6_src;
353
				tha.port = dport << 16 | sport;
354
			} else {
355
				tha.dst = ip6->ip6_dst;
356
				tha.src = ip6->ip6_src;
357
				tha.port = sport << 16 | dport;
358
			}
359
		} else {
360
			if (sport > dport ||
361
			    (sport == dport &&
362
			     ip->ip_src.s_addr > ip->ip_dst.s_addr)) {
363
				rev = 1;
364
			}
365
			if (rev) {
366
				*(struct in_addr *)&tha.src = ip->ip_dst;
367
				*(struct in_addr *)&tha.dst = ip->ip_src;
368
				tha.port = dport << 16 | sport;
369
			} else {
370
				*(struct in_addr *)&tha.dst = ip->ip_dst;
371
				*(struct in_addr *)&tha.src = ip->ip_src;
372
				tha.port = sport << 16 | dport;
373
			}
374
		}
375
#else
376
		if (sport < dport ||
377
		    (sport == dport &&
378
		     ip->ip_src.s_addr < ip->ip_dst.s_addr)) {
379
			tha.src = ip->ip_src, tha.dst = ip->ip_dst;
380
			tha.port = sport << 16 | dport;
381
			rev = 0;
382
		} else {
383
			tha.src = ip->ip_dst, tha.dst = ip->ip_src;
384
			tha.port = dport << 16 | sport;
385
			rev = 1;
386
		}
387
#endif
388
389
		for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
390
		     th->nxt; th = th->nxt)
391
			if (!memcmp((char *)&tha, (char *)&th->addr,
392
				  sizeof(th->addr)))
393
				break;
394
395
		if (!th->nxt || flags & TH_SYN) {
396
			/* didn't find it or new conversation */
397
			if (th->nxt == NULL) {
398
				th->nxt = calloc(1, sizeof(*th));
399
				if (th->nxt == NULL)
400
					error("tcp_print: calloc");
401
			}
402
			th->addr = tha;
403
			if (rev)
404
				th->ack = seq, th->seq = ack - 1;
405
			else
406
				th->seq = seq, th->ack = ack - 1;
407
		} else {
408
			if (rev)
409
				seq -= th->ack, ack -= th->seq;
410
			else
411
				seq -= th->seq, ack -= th->ack;
412
		}
413
	}
414
	hlen = tp->th_off * 4;
415
	if (hlen > length) {
416
		(void)printf(" [bad hdr length]");
417
		return;
418
	}
419
420
	if (ip && ip->ip_v == 4 && vflag) {
421
		if (TTEST2(tp->th_sport, length)) {
422
			u_int16_t sum, tcp_sum;
423
			sum = tcp_cksum(ip, tp, length);
424
			if (sum != 0) {
425
				tcp_sum = EXTRACT_16BITS(&tp->th_sum);
426
				(void)printf(" [bad tcp cksum %x! -> %x]", tcp_sum,
427
				    in_cksum_shouldbe(tcp_sum, sum));
428
			} else
429
				(void)printf(" [tcp sum ok]");
430
		}
431
	}
432
#ifdef INET6
433
	if (ip6 && ip6->ip6_plen && vflag) {
434
		if (TTEST2(tp->th_sport, length)) {
435
			u_int16_t sum, tcp_sum;
436
			sum = tcp6_cksum(ip6, tp, length);
437
			if (sum != 0) {
438
				tcp_sum = EXTRACT_16BITS(&tp->th_sum);
439
				(void)printf(" [bad tcp cksum %x! -> %x]", tcp_sum,
440
				    in_cksum_shouldbe(tcp_sum, sum));
441
			} else
442
				(void)printf(" [tcp sum ok]");
443
		}
444
	}
445
#endif
446
447
	/* OS Fingerprint */
448
	if (oflag && (flags & (TH_SYN|TH_ACK)) == TH_SYN) {
449
		struct pf_osfp_enlist *head = NULL;
450
		struct pf_osfp_entry *fp;
451
		unsigned long left;
452
		left = (unsigned long)(snapend - (const u_char *)tp);
453
454
		if (left >= hlen)
455
			head = pf_osfp_fingerprint_hdr(ip, ip6, tp);
456
		if (head) {
457
			int prev = 0;
458
			printf(" (src OS:");
459
			SLIST_FOREACH(fp, head, fp_entry) {
460
				if (fp->fp_enflags & PF_OSFP_EXPANDED)
461
					continue;
462
				if (prev)
463
					printf(",");
464
				printf(" %s", fp->fp_class_nm);
465
				if (fp->fp_version_nm[0])
466
					printf(" %s", fp->fp_version_nm);
467
				if (fp->fp_subtype_nm[0])
468
					printf(" %s", fp->fp_subtype_nm);
469
				prev = 1;
470
			}
471
			printf(")");
472
		} else {
473
			if (left < hlen)
474
				printf(" (src OS: short-pkt)");
475
			else
476
				printf(" (src OS: unknown)");
477
		}
478
	}
479
480
	length -= hlen;
481
	if (vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST))
482
		(void)printf(" %u:%u(%u)", seq, seq + length, length);
483
	if (flags & TH_ACK)
484
		(void)printf(" ack %u", ack);
485
486
	(void)printf(" win %u", win);
487
488
	if (flags & TH_URG)
489
		(void)printf(" urg %u", urp);
490
	/*
491
	 * Handle any options.
492
	 */
493
	if ((hlen -= sizeof(*tp)) > 0) {
494
		const u_char *cp;
495
		int i, opt, len, datalen;
496
497
		cp = (const u_char *)tp + sizeof(*tp);
498
		putchar(' ');
499
		ch = '<';
500
		while (hlen > 0) {
501
			putchar(ch);
502
			TCHECK(*cp);
503
			opt = *cp++;
504
			if (ZEROLENOPT(opt))
505
				len = 1;
506
			else {
507
				TCHECK(*cp);
508
				len = *cp++;	/* total including type, len */
509
				if (len < 2 || len > hlen)
510
					goto bad;
511
				--hlen;		/* account for length byte */
512
			}
513
			--hlen;			/* account for type byte */
514
			datalen = 0;
515
516
/* Bail if "l" bytes of data are not left or were not captured  */
517
#define LENCHECK(l) { if ((l) > hlen) goto bad; TCHECK2(*cp, l); }
518
519
			switch (opt) {
520
521
			case TCPOPT_MAXSEG:
522
				(void)printf("mss");
523
				datalen = 2;
524
				LENCHECK(datalen);
525
				(void)printf(" %u", EXTRACT_16BITS(cp));
526
527
				break;
528
529
			case TCPOPT_EOL:
530
				(void)printf("eol");
531
				break;
532
533
			case TCPOPT_NOP:
534
				(void)printf("nop");
535
				break;
536
537
			case TCPOPT_WSCALE:
538
				(void)printf("wscale");
539
				datalen = 1;
540
				LENCHECK(datalen);
541
				(void)printf(" %u", *cp);
542
				break;
543
544
			case TCPOPT_SACKOK:
545
				(void)printf("sackOK");
546
				if (len != 2)
547
					(void)printf("[len %d]", len);
548
				break;
549
550
			case TCPOPT_SACK:
551
			{
552
				u_long s, e;
553
554
				datalen = len - 2;
555
				if ((datalen % TCPOLEN_SACK) != 0 ||
556
				    !(flags & TH_ACK)) {
557
				         (void)printf("malformed sack ");
558
					 (void)printf("[len %d] ", datalen);
559
					 break;
560
				}
561
				printf("sack %d ", datalen/TCPOLEN_SACK);
562
				for (i = 0; i < datalen; i += TCPOLEN_SACK) {
563
					LENCHECK (i + TCPOLEN_SACK);
564
					s = EXTRACT_32BITS(cp + i);
565
					e = EXTRACT_32BITS(cp + i + 4);
566
					if (!Sflag) {
567
						if (rev) {
568
							s -= th->seq;
569
							e -= th->seq;
570
						} else {
571
							s -= th->ack;
572
							e -= th->ack;
573
						}
574
					}
575
					(void) printf("{%lu:%lu} ", s, e);
576
				}
577
				break;
578
			}
579
			case TCPOPT_ECHO:
580
				(void)printf("echo");
581
				datalen = 4;
582
				LENCHECK(datalen);
583
				(void)printf(" %u", EXTRACT_32BITS(cp));
584
				break;
585
586
			case TCPOPT_ECHOREPLY:
587
				(void)printf("echoreply");
588
				datalen = 4;
589
				LENCHECK(datalen);
590
				(void)printf(" %u", EXTRACT_32BITS(cp));
591
				break;
592
593
			case TCPOPT_TIMESTAMP:
594
				(void)printf("timestamp");
595
				datalen = 8;
596
				LENCHECK(4);
597
				(void)printf(" %u", EXTRACT_32BITS(cp));
598
				LENCHECK(datalen);
599
				(void)printf(" %u", EXTRACT_32BITS(cp + 4));
600
				break;
601
602
			case TCPOPT_CC:
603
				(void)printf("cc");
604
				datalen = 4;
605
				LENCHECK(datalen);
606
				(void)printf(" %u", EXTRACT_32BITS(cp));
607
				break;
608
609
			case TCPOPT_CCNEW:
610
				(void)printf("ccnew");
611
				datalen = 4;
612
				LENCHECK(datalen);
613
				(void)printf(" %u", EXTRACT_32BITS(cp));
614
				break;
615
616
			case TCPOPT_CCECHO:
617
				(void)printf("ccecho");
618
				datalen = 4;
619
				LENCHECK(datalen);
620
				(void)printf(" %u", EXTRACT_32BITS(cp));
621
				break;
622
623
			case TCPOPT_SIGNATURE:
624
				(void)printf("tcpmd5:");
625
				datalen = len - 2;
626
				for (i = 0; i < datalen; ++i) {
627
					LENCHECK(i+1);
628
					(void)printf("%02x", cp[i]);
629
				}
630
				break;
631
632
			default:
633
				(void)printf("opt-%d:", opt);
634
				datalen = len - 2;
635
				for (i = 0; i < datalen; ++i) {
636
					LENCHECK(i+1);
637
					(void)printf("%02x", cp[i]);
638
				}
639
				break;
640
			}
641
642
			/* Account for data printed */
643
			cp += datalen;
644
			hlen -= datalen;
645
646
			/* Check specification against observed length */
647
			++datalen;			/* option octet */
648
			if (!ZEROLENOPT(opt))
649
				++datalen;		/* size octet */
650
			if (datalen != len)
651
				(void)printf("[len %d]", len);
652
			ch = ',';
653
			if (opt == TCPOPT_EOL)
654
				break;
655
		}
656
		putchar('>');
657
	}
658
659
	if (length <= 0)
660
		return;
661
662
	/*
663
	 * Decode payload if necessary.
664
	*/
665
	bp += (tp->th_off * 4);
666
	if (flags & TH_RST) {
667
		if (vflag)
668
			print_tcp_rst_data(bp, length);
669
	} else {
670
		if (sport == BGP_PORT || dport == BGP_PORT)
671
			bgp_print(bp, length);
672
		else if (sport == OLD_OFP_PORT || dport == OLD_OFP_PORT ||
673
		    sport == OFP_PORT || dport == OFP_PORT)
674
			ofp_print(bp, length);
675
#if 0
676
		else if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT)
677
			nbt_tcp_print(bp, length);
678
#endif
679
	}
680
	return;
681
bad:
682
	fputs("[bad opt]", stdout);
683
	if (ch != '\0')
684
		putchar('>');
685
	return;
686
trunc:
687
	fputs("[|tcp]", stdout);
688
	if (ch != '\0')
689
		putchar('>');
690
}
691
692
693
/*
694
 * RFC1122 says the following on data in RST segments:
695
 *
696
 *         4.2.2.12  RST Segment: RFC-793 Section 3.4
697
 *
698
 *            A TCP SHOULD allow a received RST segment to include data.
699
 *
700
 *            DISCUSSION
701
 *                 It has been suggested that a RST segment could contain
702
 *                 ASCII text that encoded and explained the cause of the
703
 *                 RST.  No standard has yet been established for such
704
 *                 data.
705
 *
706
 */
707
708
static void
709
print_tcp_rst_data(const u_char *sp, u_int length)
710
{
711
	int c;
712
713
	if (TTEST2(*sp, length))
714
		printf(" [RST");
715
	else
716
		printf(" [!RST");
717
	if (length > MAX_RST_DATA_LEN) {
718
		length = MAX_RST_DATA_LEN;	/* can use -X for longer */
719
		putchar('+');			/* indicate we truncate */
720
	}
721
	putchar(' ');
722
	while (length-- && sp < snapend) {
723
		c = *sp++;
724
		safeputchar(c);
725
	}
726
	putchar(']');
727
}