print-tcp.c revision 56893 
1/*
2 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code distributions
7 * retain the above copyright notice and this paragraph in its entirety, (2)
8 * distributions including binary code include the above copyright notice and
9 * this paragraph in its entirety in the documentation or other materials
10 * provided with the distribution, and (3) all advertising materials mentioning
11 * features or use of this software display the following acknowledgement:
12 * ``This product includes software developed by the University of California,
13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14 * the University nor the names of its contributors may be used to endorse
15 * or promote products derived from this software without specific prior
16 * written permission.
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20 */
21
22#ifndef lint
23static const char rcsid[] =
24    "@(#) $Header: /tcpdump/master/tcpdump/print-tcp.c,v 1.63 1999/12/22 15:44:10 itojun Exp $ (LBL)";
25#endif
26
27#ifdef HAVE_CONFIG_H
28#include "config.h"
29#endif
30
31#include <sys/param.h>
32#include <sys/time.h>
33
34#include <netinet/in.h>
35#include <netinet/in_systm.h>
36#include <netinet/ip.h>
37#include <netinet/ip_var.h>
38#include <netinet/tcp.h>
39
40#ifdef HAVE_MEMORY_H
41#include <memory.h>
42#endif
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <unistd.h>
47
48#ifdef INET6
49#include <netinet/ip6.h>
50#endif
51
52#include "interface.h"
53#include "addrtoname.h"
54#include "extract.h"
55
56/* Compatibility */
57#ifndef TCPOPT_WSCALE
58#define	TCPOPT_WSCALE		3	/* window scale factor (rfc1072) */
59#endif
60#ifndef TCPOPT_SACKOK
61#define	TCPOPT_SACKOK		4	/* selective ack ok (rfc1072) */
62#endif
63#ifndef TCPOPT_SACK
64#define	TCPOPT_SACK		5	/* selective ack (rfc1072) */
65#endif
66#ifndef TCPOPT_ECHO
67#define	TCPOPT_ECHO		6	/* echo (rfc1072) */
68#endif
69#ifndef TCPOPT_ECHOREPLY
70#define	TCPOPT_ECHOREPLY	7	/* echo (rfc1072) */
71#endif
72#ifndef TCPOPT_TIMESTAMP
73#define TCPOPT_TIMESTAMP	8	/* timestamps (rfc1323) */
74#endif
75#ifndef TCPOPT_CC
76#define TCPOPT_CC		11	/* T/TCP CC options (rfc1644) */
77#endif
78#ifndef TCPOPT_CCNEW
79#define TCPOPT_CCNEW		12	/* T/TCP CC options (rfc1644) */
80#endif
81#ifndef TCPOPT_CCECHO
82#define TCPOPT_CCECHO		13	/* T/TCP CC options (rfc1644) */
83#endif
84
85struct tha {
86#ifndef INET6
87	struct in_addr src;
88	struct in_addr dst;
89#else
90	struct in6_addr src;
91	struct in6_addr dst;
92#endif /*INET6*/
93	u_int port;
94};
95
96struct tcp_seq_hash {
97	struct tcp_seq_hash *nxt;
98	struct tha addr;
99	tcp_seq seq;
100	tcp_seq ack;
101};
102
103#define TSEQ_HASHSIZE 919
104
105/* These tcp optinos do not have the size octet */
106#define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
107
108static struct tcp_seq_hash tcp_seq_hash[TSEQ_HASHSIZE];
109
110
111#ifndef TELNET_PORT
112#define TELNET_PORT	23
113#endif
114#ifndef BGP_PORT
115#define BGP_PORT	179
116#endif
117#define NETBIOS_SSN_PORT 139
118
119void
120tcp_print(register const u_char *bp, register u_int length,
121	  register const u_char *bp2)
122{
123	register const struct tcphdr *tp;
124	register const struct ip *ip;
125	register u_char flags;
126	register int hlen;
127	register char ch;
128	u_short sport, dport, win, urp;
129	u_int32_t seq, ack, thseq, thack;
130	int threv;
131#ifdef INET6
132	register const struct ip6_hdr *ip6;
133#endif
134
135	tp = (struct tcphdr *)bp;
136	ip = (struct ip *)bp2;
137#ifdef INET6
138	if (ip->ip_v == 6)
139		ip6 = (struct ip6_hdr *)bp2;
140	else
141		ip6 = NULL;
142#endif /*INET6*/
143	ch = '\0';
144	if (!TTEST(tp->th_dport)) {
145		(void)printf("%s > %s: [|tcp]",
146			ipaddr_string(&ip->ip_src),
147			ipaddr_string(&ip->ip_dst));
148		return;
149	}
150
151	sport = ntohs(tp->th_sport);
152	dport = ntohs(tp->th_dport);
153
154#ifdef INET6
155	if (ip6) {
156		if (ip6->ip6_nxt == IPPROTO_TCP) {
157			(void)printf("%s.%s > %s.%s: ",
158				ip6addr_string(&ip6->ip6_src),
159				tcpport_string(sport),
160				ip6addr_string(&ip6->ip6_dst),
161				tcpport_string(dport));
162		} else {
163			(void)printf("%s > %s: ",
164				tcpport_string(sport), tcpport_string(dport));
165		}
166	} else
167#endif /*INET6*/
168	{
169		if (ip->ip_p == IPPROTO_TCP) {
170			(void)printf("%s.%s > %s.%s: ",
171				ipaddr_string(&ip->ip_src),
172				tcpport_string(sport),
173				ipaddr_string(&ip->ip_dst),
174				tcpport_string(dport));
175		} else {
176			(void)printf("%s > %s: ",
177				tcpport_string(sport), tcpport_string(dport));
178		}
179	}
180
181	TCHECK(*tp);
182
183	seq = ntohl(tp->th_seq);
184	ack = ntohl(tp->th_ack);
185	win = ntohs(tp->th_win);
186	urp = ntohs(tp->th_urp);
187
188	if (qflag) {
189		(void)printf("tcp %d", length - tp->th_off * 4);
190		return;
191	}
192#ifdef TH_ECN
193	if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH|TH_ECN))
194#else
195	if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH))
196#endif
197	{
198		if (flags & TH_SYN)
199			putchar('S');
200		if (flags & TH_FIN)
201			putchar('F');
202		if (flags & TH_RST)
203			putchar('R');
204		if (flags & TH_PUSH)
205			putchar('P');
206#ifdef TH_ECN
207		if (flags & TH_ECN)
208			putchar('C');
209#endif
210	} else
211		putchar('.');
212
213	if (flags&0xc0) {
214		printf(" [");
215		if (flags&0x40)
216			printf("ECN-Echo");
217		if (flags&0x80)
218			printf("%sCWR", (flags&0x40) ? "," : "");
219		printf("]");
220	}
221
222	if (!Sflag && (flags & TH_ACK)) {
223		register struct tcp_seq_hash *th;
224		register int rev;
225		struct tha tha;
226		/*
227		 * Find (or record) the initial sequence numbers for
228		 * this conversation.  (we pick an arbitrary
229		 * collating order so there's only one entry for
230		 * both directions).
231		 */
232#ifdef INET6
233		bzero(&tha, sizeof(tha));
234		rev = 0;
235		if (ip6) {
236			if (sport > dport) {
237				rev = 1;
238			} else if (sport == dport) {
239			    int i;
240
241			    for (i = 0; i < 4; i++) {
242				if (((u_int32_t *)(&ip6->ip6_src))[i] >
243				    ((u_int32_t *)(&ip6->ip6_dst))[i]) {
244					rev = 1;
245					break;
246				}
247			    }
248			}
249			if (rev) {
250				tha.src = ip6->ip6_dst;
251				tha.dst = ip6->ip6_src;
252				tha.port = dport << 16 | sport;
253			} else {
254				tha.dst = ip6->ip6_dst;
255				tha.src = ip6->ip6_src;
256				tha.port = sport << 16 | dport;
257			}
258		} else {
259			if (sport > dport ||
260			    (sport == dport &&
261			     ip->ip_src.s_addr > ip->ip_dst.s_addr)) {
262				rev = 1;
263			}
264			if (rev) {
265				*(struct in_addr *)&tha.src = ip->ip_dst;
266				*(struct in_addr *)&tha.dst = ip->ip_src;
267				tha.port = dport << 16 | sport;
268			} else {
269				*(struct in_addr *)&tha.dst = ip->ip_dst;
270				*(struct in_addr *)&tha.src = ip->ip_src;
271				tha.port = sport << 16 | dport;
272			}
273		}
274#else
275		if (sport < dport ||
276		    (sport == dport &&
277		     ip->ip_src.s_addr < ip->ip_dst.s_addr)) {
278			tha.src = ip->ip_src, tha.dst = ip->ip_dst;
279			tha.port = sport << 16 | dport;
280			rev = 0;
281		} else {
282			tha.src = ip->ip_dst, tha.dst = ip->ip_src;
283			tha.port = dport << 16 | sport;
284			rev = 1;
285		}
286#endif
287
288		threv = rev;
289		for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
290		     th->nxt; th = th->nxt)
291			if (!memcmp((char *)&tha, (char *)&th->addr,
292				  sizeof(th->addr)))
293				break;
294
295		if (!th->nxt || flags & TH_SYN) {
296			/* didn't find it or new conversation */
297			if (th->nxt == NULL) {
298				th->nxt = (struct tcp_seq_hash *)
299					calloc(1, sizeof(*th));
300				if (th->nxt == NULL)
301					error("tcp_print: calloc");
302			}
303			th->addr = tha;
304			if (rev)
305				th->ack = seq, th->seq = ack - 1;
306			else
307				th->seq = seq, th->ack = ack - 1;
308		} else {
309
310			thseq = th->seq;
311			thack = th->ack;
312
313			if (rev)
314				seq -= th->ack, ack -= th->seq;
315			else
316				seq -= th->seq, ack -= th->ack;
317		}
318	}
319	hlen = tp->th_off * 4;
320	if (hlen > length) {
321		(void)printf(" [bad hdr length]");
322		return;
323	}
324	length -= hlen;
325	if (vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST))
326		(void)printf(" %u:%u(%d)", seq, seq + length, length);
327	if (flags & TH_ACK)
328		(void)printf(" ack %u", ack);
329
330	(void)printf(" win %d", win);
331
332	if (flags & TH_URG)
333		(void)printf(" urg %d", urp);
334	/*
335	 * Handle any options.
336	 */
337	if ((hlen -= sizeof(*tp)) > 0) {
338		register const u_char *cp;
339		register int i, opt, len, datalen;
340
341		cp = (const u_char *)tp + sizeof(*tp);
342		putchar(' ');
343		ch = '<';
344		while (hlen > 0) {
345			putchar(ch);
346			TCHECK(*cp);
347			opt = *cp++;
348			if (ZEROLENOPT(opt))
349				len = 1;
350			else {
351				TCHECK(*cp);
352				len = *cp++;	/* total including type, len */
353				if (len < 2 || len > hlen)
354					goto bad;
355				--hlen;		/* account for length byte */
356			}
357			--hlen;			/* account for type byte */
358			datalen = 0;
359
360/* Bail if "l" bytes of data are not left or were not captured  */
361#define LENCHECK(l) { if ((l) > hlen) goto bad; TCHECK2(*cp, l); }
362
363			switch (opt) {
364
365			case TCPOPT_MAXSEG:
366				(void)printf("mss");
367				datalen = 2;
368				LENCHECK(datalen);
369				(void)printf(" %u", EXTRACT_16BITS(cp));
370
371				break;
372
373			case TCPOPT_EOL:
374				(void)printf("eol");
375				break;
376
377			case TCPOPT_NOP:
378				(void)printf("nop");
379				break;
380
381			case TCPOPT_WSCALE:
382				(void)printf("wscale");
383				datalen = 1;
384				LENCHECK(datalen);
385				(void)printf(" %u", *cp);
386				break;
387
388			case TCPOPT_SACKOK:
389				(void)printf("sackOK");
390				break;
391
392			case TCPOPT_SACK:
393				(void)printf("sack");
394				datalen = len - 2;
395				if (datalen % 8 != 0) {
396					(void)printf(" malformed sack ");
397				} else {
398					u_int32_t s, e;
399
400					(void)printf(" sack %d ", datalen / 8);
401					for (i = 0; i < datalen; i += 8) {
402						LENCHECK(i + 4);
403						s = EXTRACT_32BITS(cp + i);
404						LENCHECK(i + 8);
405						e = EXTRACT_32BITS(cp + i + 4);
406						if (threv) {
407							s -= thseq;
408							e -= thseq;
409						} else {
410							s -= thack;
411							e -= thack;
412						}
413						(void)printf("{%u:%u}", s, e);
414					}
415					(void)printf(" ");
416				}
417				break;
418
419			case TCPOPT_ECHO:
420				(void)printf("echo");
421				datalen = 4;
422				LENCHECK(datalen);
423				(void)printf(" %u", EXTRACT_32BITS(cp));
424				break;
425
426			case TCPOPT_ECHOREPLY:
427				(void)printf("echoreply");
428				datalen = 4;
429				LENCHECK(datalen);
430				(void)printf(" %u", EXTRACT_32BITS(cp));
431				break;
432
433			case TCPOPT_TIMESTAMP:
434				(void)printf("timestamp");
435				datalen = 8;
436				LENCHECK(4);
437				(void)printf(" %u", EXTRACT_32BITS(cp));
438				LENCHECK(datalen);
439				(void)printf(" %u", EXTRACT_32BITS(cp + 4));
440				break;
441
442			case TCPOPT_CC:
443				(void)printf("cc");
444				datalen = 4;
445				LENCHECK(datalen);
446				(void)printf(" %u", EXTRACT_32BITS(cp));
447				break;
448
449			case TCPOPT_CCNEW:
450				(void)printf("ccnew");
451				datalen = 4;
452				LENCHECK(datalen);
453				(void)printf(" %u", EXTRACT_32BITS(cp));
454				break;
455
456			case TCPOPT_CCECHO:
457				(void)printf("ccecho");
458				datalen = 4;
459				LENCHECK(datalen);
460				(void)printf(" %u", EXTRACT_32BITS(cp));
461				break;
462
463			default:
464				(void)printf("opt-%d:", opt);
465				datalen = len - 2;
466				for (i = 0; i < datalen; ++i) {
467					LENCHECK(i);
468					(void)printf("%02x", cp[i]);
469				}
470				break;
471			}
472
473			/* Account for data printed */
474			cp += datalen;
475			hlen -= datalen;
476
477			/* Check specification against observed length */
478			++datalen;			/* option octet */
479			if (!ZEROLENOPT(opt))
480				++datalen;		/* size octet */
481			if (datalen != len)
482				(void)printf("[len %d]", len);
483			ch = ',';
484			if (opt == TCPOPT_EOL)
485				break;
486		}
487		putchar('>');
488	}
489
490	if (length <= 0)
491		return;
492
493	/*
494	 * Decode payload if necessary.
495	 */
496	bp += (tp->th_off * 4);
497	if (!qflag && vflag && length > 0
498	 && (sport == TELNET_PORT || dport == TELNET_PORT))
499		telnet_print(bp, length);
500	else if (sport == BGP_PORT || dport == BGP_PORT)
501		bgp_print(bp, length);
502	else if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT)
503		nbt_tcp_print(bp, length);
504	return;
505bad:
506	fputs("[bad opt]", stdout);
507	if (ch != '\0')
508		putchar('>');
509	return;
510trunc:
511	fputs("[|tcp]", stdout);
512	if (ch != '\0')
513		putchar('>');
514}
515
516