print-dccp.c revision 172683 
1/*
2 * Copyright (C) Arnaldo Carvalho de Melo 2004
3 * Copyright (C) Ian McDonald 2005
4 * Copyright (C) Yoshifumi Nishida 2005
5 *
6 * This software may be distributed either under the terms of the
7 * BSD-style license that accompanies tcpdump or the GNU GPL version 2
8 */
9
10#ifndef lint
11static const char rcsid[] _U_ =
12    "@(#) $Header: /tcpdump/master/tcpdump/print-dccp.c,v 1.1.2.6 2006/02/19 05:08:44 guy Exp $ (LBL)";
13#endif
14
15#ifdef HAVE_CONFIG_H
16#include "config.h"
17#endif
18
19#include <tcpdump-stdinc.h>
20
21#include "dccp.h"
22
23#include <stdio.h>
24#include <string.h>
25
26#include "interface.h"
27#include "addrtoname.h"
28#include "extract.h"			/* must come after interface.h */
29#include "ip.h"
30#ifdef INET6
31#include "ip6.h"
32#endif
33#include "ipproto.h"
34
35static const char *dccp_reset_codes[] = {
36	"unspecified",
37	"closed",
38	"aborted",
39	"no_connection",
40	"packet_error",
41	"option_error",
42	"mandatory_error",
43	"connection_refused",
44	"bad_service_code",
45	"too_busy",
46	"bad_init_cookie",
47	"aggression_penalty",
48};
49
50static const char *dccp_feature_nums[] = {
51	"reserved",
52	"ccid",
53	"allow_short_seqno",
54	"sequence_window",
55	"ecn_incapable",
56	"ack_ratio",
57	"send_ack_vector",
58	"send_ndp_count",
59	"minimum checksum coverage",
60	"check data checksum",
61};
62
63static int dccp_cksum(const struct ip *ip,
64	const struct dccp_hdr *dh, u_int len)
65{
66	union phu {
67		struct phdr {
68			u_int32_t src;
69			u_int32_t dst;
70			u_char mbz;
71			u_char proto;
72			u_int16_t len;
73		} ph;
74		u_int16_t pa[6];
75	} phu;
76	const u_int16_t *sp;
77
78	/* pseudo-header.. */
79	phu.ph.mbz = 0;
80	phu.ph.len = htons(len);
81	phu.ph.proto = IPPROTO_DCCP;
82	memcpy(&phu.ph.src, &ip->ip_src.s_addr, sizeof(u_int32_t));
83	if (IP_HL(ip) == 5)
84		memcpy(&phu.ph.dst, &ip->ip_dst.s_addr, sizeof(u_int32_t));
85	else
86		phu.ph.dst = ip_finddst(ip);
87
88	sp = &phu.pa[0];
89	return in_cksum((u_short *)dh, len, sp[0]+sp[1]+sp[2]+sp[3]+sp[4]+sp[5]);
90}
91
92#ifdef INET6
93static int dccp6_cksum(const struct ip6_hdr *ip6, const struct dccp_hdr *dh, u_int len)
94{
95	size_t i;
96	const u_int16_t *sp;
97	u_int32_t sum;
98	union {
99		struct {
100			struct in6_addr ph_src;
101			struct in6_addr ph_dst;
102			u_int32_t   ph_len;
103			u_int8_t    ph_zero[3];
104			u_int8_t    ph_nxt;
105		} ph;
106		u_int16_t pa[20];
107	} phu;
108
109	/* pseudo-header */
110	memset(&phu, 0, sizeof(phu));
111	phu.ph.ph_src = ip6->ip6_src;
112	phu.ph.ph_dst = ip6->ip6_dst;
113	phu.ph.ph_len = htonl(len);
114	phu.ph.ph_nxt = IPPROTO_DCCP;
115
116	sum = 0;
117	for (i = 0; i < sizeof(phu.pa) / sizeof(phu.pa[0]); i++)
118		sum += phu.pa[i];
119
120	sp = (const u_int16_t *)dh;
121
122	for (i = 0; i < (len & ~1); i += 2)
123		sum += *sp++;
124
125	if (len & 1)
126		sum += htons((*(const u_int8_t *)sp) << 8);
127
128	while (sum > 0xffff)
129		sum = (sum & 0xffff) + (sum >> 16);
130	sum = ~sum & 0xffff;
131
132	return (sum);
133}
134#endif
135
136static const char *dccp_reset_code(u_int8_t code)
137{
138	if (code >= __DCCP_RESET_CODE_LAST)
139		return "invalid";
140	return dccp_reset_codes[code];
141}
142
143static u_int64_t dccp_seqno(const struct dccp_hdr *dh)
144{
145	u_int32_t seq_high = DCCPH_SEQ(dh);
146	u_int64_t seqno = EXTRACT_24BITS(&seq_high) & 0xFFFFFF;
147
148	if (DCCPH_X(dh) != 0) {
149		const struct dccp_hdr_ext *dhx = (void *)(dh + 1);
150		u_int32_t seq_low = dhx->dccph_seq_low;
151		seqno &= 0x00FFFF;  /* clear reserved field */
152		seqno = (seqno << 32) + EXTRACT_32BITS(&seq_low);
153	}
154
155	return seqno;
156}
157
158static inline unsigned int dccp_basic_hdr_len(const struct dccp_hdr *dh)
159{
160	return sizeof(*dh) + (DCCPH_X(dh) ? sizeof(struct dccp_hdr_ext) : 0);
161}
162
163static void dccp_print_ack_no(const u_char *bp)
164{
165	const struct dccp_hdr *dh = (const struct dccp_hdr *)bp;
166	const struct dccp_hdr_ack_bits *dh_ack =
167		(struct dccp_hdr_ack_bits *)(bp + dccp_basic_hdr_len(dh));
168	u_int32_t ack_high;
169	u_int64_t ackno;
170
171	TCHECK2(*dh_ack,4);
172	ack_high = DCCPH_ACK(dh_ack);
173	ackno = EXTRACT_24BITS(&ack_high) & 0xFFFFFF;
174
175	if (DCCPH_X(dh) != 0) {
176		u_int32_t ack_low;
177
178		TCHECK2(*dh_ack,8);
179		ack_low = dh_ack->dccph_ack_nr_low;
180
181		ackno &= 0x00FFFF;  /* clear reserved field */
182		ackno = (ackno << 32) + EXTRACT_32BITS(&ack_low);
183	}
184
185	(void)printf("(ack=%" PRIu64 ") ", ackno);
186trunc:
187	return;
188}
189
190static inline unsigned int dccp_packet_hdr_len(const u_int8_t type)
191{
192	if (type == DCCP_PKT_DATA)
193		return 0;
194	if (type == DCCP_PKT_DATAACK	||
195	    type == DCCP_PKT_ACK	||
196	    type == DCCP_PKT_SYNC	||
197	    type == DCCP_PKT_SYNCACK	||
198	    type == DCCP_PKT_CLOSE	||
199	    type == DCCP_PKT_CLOSEREQ)
200		return sizeof(struct dccp_hdr_ack_bits);
201	if (type == DCCP_PKT_REQUEST)
202		return sizeof(struct dccp_hdr_request);
203	if (type == DCCP_PKT_RESPONSE)
204		return sizeof(struct dccp_hdr_response);
205	return sizeof(struct dccp_hdr_reset);
206}
207
208static int dccp_print_option(const u_char *option);
209
210/**
211 * dccp_print - show dccp packet
212 * @bp - beginning of dccp packet
213 * @data2 - beginning of enclosing
214 * @len - lenght of ip packet
215 */
216void dccp_print(const u_char *bp, const u_char *data2, u_int len)
217{
218	const struct dccp_hdr *dh;
219	const struct ip *ip;
220#ifdef INET6
221	const struct ip6_hdr *ip6;
222#endif
223	const u_char *cp;
224	u_short sport, dport;
225	u_int hlen;
226	u_int extlen = 0;
227
228	dh = (const struct dccp_hdr *)bp;
229
230	ip = (struct ip *)data2;
231#ifdef INET6
232	if (IP_V(ip) == 6)
233		ip6 = (const struct ip6_hdr *)data2;
234	else
235		ip6 = NULL;
236#endif /*INET6*/
237	cp = (const u_char *)(dh + 1);
238	if (cp > snapend) {
239		printf("[Invalid packet|dccp]");
240		return;
241	}
242
243	if (len < sizeof(struct dccp_hdr)) {
244		printf("truncated-dccp - %ld bytes missing!",
245			     (long)len - sizeof(struct dccp_hdr));
246		return;
247	}
248
249	sport = EXTRACT_16BITS(&dh->dccph_sport);
250	dport = EXTRACT_16BITS(&dh->dccph_dport);
251	hlen = dh->dccph_doff * 4;
252
253#ifdef INET6
254	if (ip6) {
255		(void)printf("%s.%d > %s.%d: ",
256			     ip6addr_string(&ip6->ip6_src), sport,
257			     ip6addr_string(&ip6->ip6_dst), dport);
258	} else
259#endif /*INET6*/
260	{
261		(void)printf("%s.%d > %s.%d: ",
262			     ipaddr_string(&ip->ip_src), sport,
263			     ipaddr_string(&ip->ip_dst), dport);
264	}
265	fflush(stdout);
266
267	if (qflag) {
268		(void)printf(" %d", len - hlen);
269		if (hlen > len) {
270			(void)printf("dccp [bad hdr length %u - too long, > %u]",
271			    hlen, len);
272		}
273		return;
274	}
275
276	/* other variables in generic header */
277	if (vflag) {
278		(void)printf("CCVal %d, CsCov %d, ", DCCPH_CCVAL(dh), DCCPH_CSCOV(dh));
279	}
280
281	/* checksum calculation */
282#ifdef INET6
283	if (ip6) {
284		if (ip6->ip6_plen && vflag) {
285			u_int16_t sum, dccp_sum;
286
287			sum = dccp6_cksum(ip6, dh, len);
288			dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);
289			printf("cksum 0x%04x", dccp_sum);
290			if (sum != 0) {
291				(void)printf(" (incorrect (-> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
292			} else
293				(void)printf(" (correct), ");
294		}
295	} else
296#endif /* INET6 */
297	if (vflag)
298	{
299		u_int16_t sum, dccp_sum;
300
301		sum = dccp_cksum(ip, dh, len);
302		dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);
303		printf("cksum 0x%04x", dccp_sum);
304		if (sum != 0) {
305			(void)printf(" (incorrect (-> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
306		} else
307			(void)printf(" (correct), ");
308	}
309
310	switch (DCCPH_TYPE(dh)) {
311	case DCCP_PKT_REQUEST: {
312		struct dccp_hdr_request *dhr =
313			(struct dccp_hdr_request *)(bp + dccp_basic_hdr_len(dh));
314		TCHECK(*dhr);
315		(void)printf("request (service=%d) ",
316			     EXTRACT_32BITS(&dhr->dccph_req_service));
317		extlen += 4;
318		break;
319	}
320	case DCCP_PKT_RESPONSE: {
321		struct dccp_hdr_response *dhr =
322			(struct dccp_hdr_response *)(bp + dccp_basic_hdr_len(dh));
323		TCHECK(*dhr);
324		(void)printf("response (service=%d) ",
325			     EXTRACT_32BITS(&dhr->dccph_resp_service));
326		extlen += 12;
327		break;
328	}
329	case DCCP_PKT_DATA:
330		(void)printf("data ");
331		break;
332	case DCCP_PKT_ACK: {
333		(void)printf("ack ");
334		extlen += 8;
335		break;
336	}
337	case DCCP_PKT_DATAACK: {
338		(void)printf("dataack ");
339		extlen += 8;
340		break;
341	}
342	case DCCP_PKT_CLOSEREQ:
343		(void)printf("closereq ");
344		extlen += 8;
345		break;
346	case DCCP_PKT_CLOSE:
347		(void)printf("close ");
348		extlen += 8;
349		break;
350	case DCCP_PKT_RESET: {
351		struct dccp_hdr_reset *dhr =
352			(struct dccp_hdr_reset *)(bp + dccp_basic_hdr_len(dh));
353		TCHECK(*dhr);
354		(void)printf("reset (code=%s) ",
355			     dccp_reset_code(dhr->dccph_reset_code));
356		extlen += 12;
357		break;
358	}
359	case DCCP_PKT_SYNC:
360		(void)printf("sync ");
361		extlen += 8;
362		break;
363	case DCCP_PKT_SYNCACK:
364		(void)printf("syncack ");
365		extlen += 8;
366		break;
367	default:
368		(void)printf("invalid ");
369		break;
370	}
371
372	if ((DCCPH_TYPE(dh) != DCCP_PKT_DATA) &&
373			(DCCPH_TYPE(dh) != DCCP_PKT_REQUEST))
374		dccp_print_ack_no(bp);
375
376	if (vflag < 2)
377		return;
378
379	(void)printf("seq %" PRIu64, dccp_seqno(dh));
380
381	/* process options */
382	if (hlen > dccp_basic_hdr_len(dh) + extlen){
383		const u_char *cp;
384		u_int optlen;
385		cp = bp + dccp_basic_hdr_len(dh) + extlen;
386		printf(" <");
387
388		hlen -= dccp_basic_hdr_len(dh) + extlen;
389		while(1){
390			TCHECK(*cp);
391			optlen = dccp_print_option(cp);
392			if (!optlen) goto trunc2;
393			if (hlen <= optlen) break;
394			hlen -= optlen;
395			cp += optlen;
396			printf(", ");
397		}
398		printf(">");
399	}
400	return;
401trunc:
402	printf("[|dccp]");
403trunc2:
404	return;
405}
406
407static int dccp_print_option(const u_char *option)
408{
409	u_int8_t optlen, i;
410	u_int32_t *ts;
411	u_int16_t *var16;
412	u_int32_t *var32;
413
414	TCHECK(*option);
415
416	if (*option >= 32) {
417		TCHECK(*(option+1));
418		optlen = *(option +1);
419		if (optlen < 2) {
420			printf("Option %d optlen too short",*option);
421			return 1;
422		}
423	} else optlen = 1;
424
425	TCHECK2(*option,optlen);
426
427	switch (*option){
428	case 0:
429		printf("nop");
430		break;
431	case 1:
432		printf("mandatory");
433		break;
434	case 2:
435		printf("slowreceiver");
436		break;
437	case 32:
438		printf("change_l");
439		if (*(option +2) < 10){
440			printf(" %s", dccp_feature_nums[*(option +2)]);
441			for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
442		}
443		break;
444	case 33:
445		printf("confirm_l");
446		if (*(option +2) < 10){
447			printf(" %s", dccp_feature_nums[*(option +2)]);
448			for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
449		}
450		break;
451	case 34:
452	        printf("change_r");
453		if (*(option +2) < 10){
454			printf(" %s", dccp_feature_nums[*(option +2)]);
455			for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
456		}
457		break;
458	case 35:
459		printf("confirm_r");
460		if (*(option +2) < 10){
461			printf(" %s", dccp_feature_nums[*(option +2)]);
462			for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
463		}
464		break;
465	case 36:
466		printf("initcookie 0x");
467		for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
468		break;
469	case 37:
470		printf("ndp_count");
471		for (i = 0; i < optlen -2; i ++) printf(" %d", *(option +2 + i));
472		break;
473	case 38:
474		printf("ack_vector0 0x");
475		for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
476		break;
477	case 39:
478		printf("ack_vector1 0x");
479		for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
480		break;
481	case 40:
482		printf("data_dropped 0x");
483		for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
484		break;
485	case 41:
486		ts = (u_int32_t *)(option + 2);
487		printf("timestamp %u", (u_int32_t)ntohl(*ts));
488		break;
489	case 42:
490		ts = (u_int32_t *)(option + 2);
491		printf("timestamp_echo %u", (u_int32_t)ntohl(*ts));
492		break;
493	case 43:
494		printf("elapsed_time ");
495		if (optlen == 6){
496			ts = (u_int32_t *)(option + 2);
497			printf("%u", (u_int32_t)ntohl(*ts));
498		} else {
499			var16 = (u_int16_t *)(option + 2);
500			printf("%u", ntohs(*var16));
501		}
502		break;
503	case 44:
504		printf("data_checksum ");
505		for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
506		break;
507	default :
508		if (*option >= 128) {
509			printf("CCID option %d",*option);
510			switch (optlen) {
511				case 4:
512					var16 = (u_int16_t *)(option + 2);
513					printf(" %u",ntohs(*var16));
514					break;
515				case 6:
516					var32 = (u_int32_t *)(option + 2);
517					printf(" %u",(u_int32_t)ntohl(*var32));
518					break;
519				default:
520					break;
521			}
522			break;
523		}
524
525		printf("unknown_opt %d", *option);
526		break;
527	}
528
529	return optlen;
530trunc:
531	printf("[|dccp]");
532	return 0;
533}
534