1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
|
/*
* Copyright (C) Arnaldo Carvalho de Melo 2004
* Copyright (C) Ian McDonald 2005
* Copyright (C) Yoshifumi Nishida 2005
*
* This software may be distributed either under the terms of the
* BSD-style license that accompanies tcpdump or the GNU GPL version 2
*/
#ifndef lint
static const char rcsid[] _U_ =
"@(#) $Header: /tcpdump/master/tcpdump/print-dccp.c,v 1.1.2.2 2005/09/20 06:25:45 guy Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <tcpdump-stdinc.h>
#include "dccp.h"
#include <stdio.h>
#include <string.h>
#include "interface.h"
#include "addrtoname.h"
#include "extract.h" /* must come after interface.h */
#include "ip.h"
#ifdef INET6
#include "ip6.h"
#endif
#include "ipproto.h"
static const char *dccp_reset_codes[] = {
"unspecified",
"closed",
"aborted",
"no_connection",
"packet_error",
"option_error",
"mandatory_error",
"connection_refused",
"bad_service_code",
"too_busy",
"bad_init_cookie",
"aggression_penalty",
};
static const char *dccp_feature_nums[] = {
"reserved",
"ccid",
"allow_short_seqno",
"sequence_window",
"ecn_incapable",
"ack_ratio",
"send_ack_vector",
"send_ndp_count",
"minimum checksum coverage",
"check data checksum",
};
static int dccp_cksum(const struct ip *ip,
const struct dccp_hdr *dh, u_int len)
{
union phu {
struct phdr {
u_int32_t src;
u_int32_t dst;
u_char mbz;
u_char proto;
u_int16_t len;
} ph;
u_int16_t pa[6];
} phu;
const u_int16_t *sp;
/* pseudo-header.. */
phu.ph.mbz = 0;
phu.ph.len = htons(len);
phu.ph.proto = IPPROTO_DCCP;
memcpy(&phu.ph.src, &ip->ip_src.s_addr, sizeof(u_int32_t));
if (IP_HL(ip) == 5)
memcpy(&phu.ph.dst, &ip->ip_dst.s_addr, sizeof(u_int32_t));
else
phu.ph.dst = ip_finddst(ip);
sp = &phu.pa[0];
return in_cksum((u_short *)dh, len, sp[0]+sp[1]+sp[2]+sp[3]+sp[4]+sp[5]);
}
#ifdef INET6
static int dccp6_cksum(const struct ip6_hdr *ip6, const struct dccp_hdr *dh, u_int len)
{
size_t i;
const u_int16_t *sp;
u_int32_t sum;
union {
struct {
struct in6_addr ph_src;
struct in6_addr ph_dst;
u_int32_t ph_len;
u_int8_t ph_zero[3];
u_int8_t ph_nxt;
} ph;
u_int16_t pa[20];
} phu;
/* pseudo-header */
memset(&phu, 0, sizeof(phu));
phu.ph.ph_src = ip6->ip6_src;
phu.ph.ph_dst = ip6->ip6_dst;
phu.ph.ph_len = htonl(len);
phu.ph.ph_nxt = IPPROTO_DCCP;
sum = 0;
for (i = 0; i < sizeof(phu.pa) / sizeof(phu.pa[0]); i++)
sum += phu.pa[i];
sp = (const u_int16_t *)dh;
for (i = 0; i < (len & ~1); i += 2)
sum += *sp++;
if (len & 1)
sum += htons((*(const u_int8_t *)sp) << 8);
while (sum > 0xffff)
sum = (sum & 0xffff) + (sum >> 16);
sum = ~sum & 0xffff;
return (sum);
}
#endif
static const char *dccp_reset_code(u_int8_t code)
{
if (code >= __DCCP_RESET_CODE_LAST)
return "invalid";
return dccp_reset_codes[code];
}
static u_int64_t dccp_seqno(const struct dccp_hdr *dh)
{
u_int32_t seq_high = DCCPH_SEQ(dh);
u_int64_t seqno = EXTRACT_24BITS(&seq_high) & 0xFFFFFF;
if (DCCPH_X(dh) != 0) {
const struct dccp_hdr_ext *dhx = (void *)dh + sizeof(*dh);
u_int32_t seq_low = dhx->dccph_seq_low;
seqno &= 0x00FFFF; /* clear reserved field */
seqno = (seqno << 32) + EXTRACT_32BITS(&seq_low);
}
return seqno;
}
static u_int64_t dccp_ack_no(const struct dccp_hdr *dh,
const struct dccp_hdr_ack_bits *dh_ack)
{
u_int32_t ack_high = DCCPH_ACK(dh_ack);
u_int64_t ackno = EXTRACT_24BITS(&ack_high) & 0xFFFFFF;
if (DCCPH_X(dh) != 0) {
u_int32_t ack_low = dh_ack->dccph_ack_nr_low;
ackno &= 0x00FFFF; /* clear reserved field */
ackno = (ackno << 32) + EXTRACT_32BITS(&ack_low);
}
return ackno;
}
static inline unsigned int dccp_basic_hdr_len(const struct dccp_hdr *dh)
{
return sizeof(*dh) + (DCCPH_X(dh) ? sizeof(struct dccp_hdr_ext) : 0);
}
static inline unsigned int dccp_packet_hdr_len(const u_int8_t type)
{
if (type == DCCP_PKT_DATA)
return 0;
if (type == DCCP_PKT_DATAACK ||
type == DCCP_PKT_ACK ||
type == DCCP_PKT_SYNC ||
type == DCCP_PKT_SYNCACK ||
type == DCCP_PKT_CLOSE ||
type == DCCP_PKT_CLOSEREQ)
return sizeof(struct dccp_hdr_ack_bits);
if (type == DCCP_PKT_REQUEST)
return sizeof(struct dccp_hdr_request);
if (type == DCCP_PKT_RESPONSE)
return sizeof(struct dccp_hdr_response);
return sizeof(struct dccp_hdr_reset);
}
static int dccp_print_option(const u_char *option);
/**
* dccp_print - show dccp packet
* @bp - beginning of dccp packet
* @data2 - beginning of enclosing
* @len - lenght of ip packet
*/
void dccp_print(const u_char *bp, const u_char *data2, u_int len)
{
const struct dccp_hdr *dh;
const struct ip *ip;
#ifdef INET6
const struct ip6_hdr *ip6;
#endif
const u_char *cp;
u_short sport, dport;
u_int hlen;
u_int extlen = 0;
dh = (const struct dccp_hdr *)bp;
ip = (struct ip *)data2;
#ifdef INET6
if (IP_V(ip) == 6)
ip6 = (const struct ip6_hdr *)data2;
else
ip6 = NULL;
#endif /*INET6*/
cp = (const u_char *)(dh + 1);
if (cp > snapend) {
printf("[Invalid packet|dccp]");
return;
}
if (len < sizeof(struct dccp_hdr)) {
printf("truncated-dccp - %ld bytes missing!",
(long)len - sizeof(struct dccp_hdr));
return;
}
sport = EXTRACT_16BITS(&dh->dccph_sport);
dport = EXTRACT_16BITS(&dh->dccph_dport);
hlen = dh->dccph_doff * 4;
#ifdef INET6
if (ip6) {
(void)printf("%s.%d > %s.%d: ",
ip6addr_string(&ip6->ip6_src), sport,
ip6addr_string(&ip6->ip6_dst), dport);
} else
#endif /*INET6*/
{
(void)printf("%s.%d > %s.%d: ",
ipaddr_string(&ip->ip_src), sport,
ipaddr_string(&ip->ip_dst), dport);
}
fflush(stdout);
if (qflag) {
(void)printf(" %d", len - hlen);
if (hlen > len) {
(void)printf("dccp [bad hdr length %u - too long, > %u]",
hlen, len);
}
return;
}
/* other variables in generic header */
if (vflag) {
(void)printf("CCVal %d, CsCov %d, ", DCCPH_CCVAL(dh), DCCPH_CSCOV(dh));
}
/* checksum calculation */
#ifdef INET6
if (ip6) {
if (ip6->ip6_plen && vflag) {
u_int16_t sum, dccp_sum;
sum = dccp6_cksum(ip6, dh, len);
dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);
printf("cksum 0x%04x", dccp_sum);
if (sum != 0) {
(void)printf(" (incorrect (-> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
} else
(void)printf(" (correct), ");
}
} else
#endif /* INET6 */
if (vflag)
{
u_int16_t sum, dccp_sum;
sum = dccp_cksum(ip, dh, len);
dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);
printf("cksum 0x%04x", dccp_sum);
if (sum != 0) {
(void)printf(" (incorrect (-> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
} else
(void)printf(" (correct), ");
}
switch (DCCPH_TYPE(dh)) {
case DCCP_PKT_REQUEST: {
struct dccp_hdr_request *dhr =
(struct dccp_hdr_request *)(bp + dccp_basic_hdr_len(dh));
TCHECK(*dhr);
(void)printf("request (service=%d) ", dhr->dccph_req_service);
extlen += 4;
break;
}
case DCCP_PKT_RESPONSE: {
struct dccp_hdr_response *dhr =
(struct dccp_hdr_response *)(bp + dccp_basic_hdr_len(dh));
TCHECK(*dhr);
(void)printf("response (service=%d, ack=%" PRIu64 ") ",
dhr->dccph_resp_service,
dccp_ack_no(dh,&(dhr->dccph_resp_ack)));
extlen += 12;
break;
}
case DCCP_PKT_DATA:
(void)printf("data ");
break;
case DCCP_PKT_ACK: {
struct dccp_hdr_ack_bits *dha =
(struct dccp_hdr_ack_bits *)(bp + dccp_basic_hdr_len(dh));
TCHECK(*dha);
(void)printf("ack (ack=%" PRIu64 ") ",
dccp_ack_no(dh,dha));
extlen += 8;
break;
}
case DCCP_PKT_DATAACK: {
struct dccp_hdr_ack_bits *dha =
(struct dccp_hdr_ack_bits *)(bp + dccp_basic_hdr_len(dh));
TCHECK(*dha);
(void)printf("dataack (ack=%" PRIu64 ") ",
dccp_ack_no(dh,dha));
extlen += 8;
break;
}
case DCCP_PKT_CLOSEREQ:
(void)printf("closereq ");
extlen += 8;
break;
case DCCP_PKT_CLOSE:
(void)printf("close ");
extlen += 8;
break;
case DCCP_PKT_RESET: {
struct dccp_hdr_reset *dhr =
(struct dccp_hdr_reset *)(bp + dccp_basic_hdr_len(dh));
TCHECK(*dhr);
(void)printf("reset (code=%s) ",
dccp_reset_code(dhr->dccph_reset_code));
extlen += 12;
break;
}
case DCCP_PKT_SYNC:
(void)printf("sync ");
extlen += 8;
break;
case DCCP_PKT_SYNCACK:
(void)printf("syncack ");
extlen += 8;
break;
default:
(void)printf("invalid ");
break;
}
if (vflag < 2)
return;
(void)printf("seq %" PRIu64, dccp_seqno(dh));
/* process options */
if (hlen > dccp_basic_hdr_len(dh) + extlen){
const u_char *cp;
u_int optlen;
cp = bp + dccp_basic_hdr_len(dh) + extlen;
printf(" <");
hlen -= dccp_basic_hdr_len(dh) + extlen;
while(1){
TCHECK(*cp);
optlen = dccp_print_option(cp);
if (!optlen) goto trunc2;
if (hlen <= optlen) break;
hlen -= optlen;
cp += optlen;
printf(", ");
}
printf(">");
}
return;
trunc:
printf("[|dccp]");
trunc2:
return;
}
static int dccp_print_option(const u_char *option)
{
u_int8_t optlen, i;
u_int32_t *ts;
u_int16_t *var16;
u_int32_t *var32;
TCHECK(*option);
if (*option >= 32) {
TCHECK(*(option+1));
optlen = *(option +1);
if (optlen < 2) {
printf("Option %d optlen too short",*option);
return 1;
}
} else optlen = 1;
TCHECK2(*option,optlen);
switch (*option){
case 0:
printf("nop");
break;
case 1:
printf("mandatory");
break;
case 2:
printf("slowreceiver");
break;
case 32:
printf("change_l");
if (*(option +2) < 10){
printf(" %s", dccp_feature_nums[*(option +2)]);
for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
}
break;
case 33:
printf("confirm_l");
if (*(option +2) < 10){
printf(" %s", dccp_feature_nums[*(option +2)]);
for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
}
break;
case 34:
printf("change_r");
if (*(option +2) < 10){
printf(" %s", dccp_feature_nums[*(option +2)]);
for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
}
break;
case 35:
printf("confirm_r");
if (*(option +2) < 10){
printf(" %s", dccp_feature_nums[*(option +2)]);
for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
}
break;
case 36:
printf("initcookie 0x");
for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
break;
case 37:
printf("ndp_count");
for (i = 0; i < optlen -2; i ++) printf(" %d", *(option +2 + i));
break;
case 38:
printf("ack_vector0 0x");
for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
break;
case 39:
printf("ack_vector1 0x");
for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
break;
case 40:
printf("data_dropped 0x");
for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
break;
case 41:
ts = (u_int32_t *)(option + 2);
printf("timestamp %u", (u_int32_t)ntohl(*ts));
break;
case 42:
ts = (u_int32_t *)(option + 2);
printf("timestamp_echo %u", (u_int32_t)ntohl(*ts));
break;
case 43:
printf("elapsed_time ");
if (optlen == 6){
ts = (u_int32_t *)(option + 2);
printf("%u", (u_int32_t)ntohl(*ts));
} else {
var16 = (u_int16_t *)(option + 2);
printf("%u", ntohs(*var16));
}
break;
case 44:
printf("data_checksum ");
for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
break;
default :
if (*option >= 128) {
printf("CCID option %d",*option);
switch (optlen) {
case 4:
var16 = (u_int16_t *)(option + 2);
printf(" %u",ntohs(*var16));
break;
case 6:
var32 = (u_int32_t *)(option + 2);
printf(" %u",(u_int32_t)ntohl(*var32));
break;
default:
break;
}
break;
}
printf("unknown_opt %d", *option);
break;
}
return optlen;
trunc:
printf("[|dccp]");
return 0;
}
|