xref: /freebsd/contrib/tcpdump/print-tcp.c (revision daf1cffce2e07931f27c6c6998652e90df6ba87e) 
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
23 static 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 
85 struct 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 
96 struct 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 
108 static 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 
119 void
120 tcp_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;
505 bad:
506 	fputs("[bad opt]", stdout);
507 	if (ch != '\0')
508 		putchar('>');
509 	return;
510 trunc:
511 	fputs("[|tcp]", stdout);
512 	if (ch != '\0')
513 		putchar('>');
514 }
515 
516