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NDOize DCCP, Linux socket and RPKI-Router decoders
[tcpdump] / print-dccp.c
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 #ifdef HAVE_CONFIG_H
11 #include "config.h"
12 #endif
13
14 #include <tcpdump-stdinc.h>
15
16 #include <stdio.h>
17 #include <string.h>
18
19 #include "interface.h"
20 #include "addrtoname.h"
21 #include "extract.h" /* must come after interface.h */
22 #include "ip.h"
23 #ifdef INET6
24 #include "ip6.h"
25 #endif
26 #include "ipproto.h"
27
28 /**
29 * struct dccp_hdr - generic part of DCCP packet header, with a 24-bit
30 * sequence number
31 *
32 * @dccph_sport - Relevant port on the endpoint that sent this packet
33 * @dccph_dport - Relevant port on the other endpoint
34 * @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words
35 * @dccph_ccval - Used by the HC-Sender CCID
36 * @dccph_cscov - Parts of the packet that are covered by the Checksum field
37 * @dccph_checksum - Internet checksum, depends on dccph_cscov
38 * @dccph_x - 0 = 24 bit sequence number, 1 = 48
39 * @dccph_type - packet type, see DCCP_PKT_ prefixed macros
40 * @dccph_seq - 24-bit sequence number
41 */
42 struct dccp_hdr {
43 u_int16_t dccph_sport,
44 dccph_dport;
45 u_int8_t dccph_doff;
46 u_int8_t dccph_ccval_cscov;
47 u_int16_t dccph_checksum;
48 u_int8_t dccph_xtr;
49 u_int8_t dccph_seq[3];
50 } UNALIGNED;
51
52 /**
53 * struct dccp_hdr_ext - generic part of DCCP packet header, with a 48-bit
54 * sequence number
55 *
56 * @dccph_sport - Relevant port on the endpoint that sent this packet
57 * @dccph_dport - Relevant port on the other endpoint
58 * @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words
59 * @dccph_ccval - Used by the HC-Sender CCID
60 * @dccph_cscov - Parts of the packet that are covered by the Checksum field
61 * @dccph_checksum - Internet checksum, depends on dccph_cscov
62 * @dccph_x - 0 = 24 bit sequence number, 1 = 48
63 * @dccph_type - packet type, see DCCP_PKT_ prefixed macros
64 * @dccph_seq - 48-bit sequence number
65 */
66 struct dccp_hdr_ext {
67 u_int16_t dccph_sport,
68 dccph_dport;
69 u_int8_t dccph_doff;
70 u_int8_t dccph_ccval_cscov;
71 u_int16_t dccph_checksum;
72 u_int8_t dccph_xtr;
73 u_int8_t reserved;
74 u_int8_t dccph_seq[6];
75 } UNALIGNED;
76
77 #define DCCPH_CCVAL(dh) (((dh)->dccph_ccval_cscov >> 4) & 0xF)
78 #define DCCPH_CSCOV(dh) (((dh)->dccph_ccval_cscov) & 0xF)
79
80 #define DCCPH_X(dh) ((dh)->dccph_xtr & 1)
81 #define DCCPH_TYPE(dh) (((dh)->dccph_xtr >> 1) & 0xF)
82
83 /**
84 * struct dccp_hdr_request - Conection initiation request header
85 *
86 * @dccph_req_service - Service to which the client app wants to connect
87 */
88 struct dccp_hdr_request {
89 u_int32_t dccph_req_service;
90 } UNALIGNED;
91
92 /**
93 * struct dccp_hdr_response - Conection initiation response header
94 *
95 * @dccph_resp_ack - 48 bit ack number, contains GSR
96 * @dccph_resp_service - Echoes the Service Code on a received DCCP-Request
97 */
98 struct dccp_hdr_response {
99 u_int8_t dccph_resp_ack[8]; /* always 8 bytes */
100 u_int32_t dccph_resp_service;
101 } UNALIGNED;
102
103 /**
104 * struct dccp_hdr_reset - Unconditionally shut down a connection
105 *
106 * @dccph_resp_ack - 48 bit ack number
107 * @dccph_reset_service - Echoes the Service Code on a received DCCP-Request
108 */
109 struct dccp_hdr_reset {
110 u_int8_t dccph_reset_ack[8]; /* always 8 bytes */
111 u_int8_t dccph_reset_code,
112 dccph_reset_data[3];
113 } UNALIGNED;
114
115 enum dccp_pkt_type {
116 DCCP_PKT_REQUEST = 0,
117 DCCP_PKT_RESPONSE,
118 DCCP_PKT_DATA,
119 DCCP_PKT_ACK,
120 DCCP_PKT_DATAACK,
121 DCCP_PKT_CLOSEREQ,
122 DCCP_PKT_CLOSE,
123 DCCP_PKT_RESET,
124 DCCP_PKT_SYNC,
125 DCCP_PKT_SYNCACK,
126 DCCP_PKT_INVALID
127 };
128
129 enum dccp_reset_codes {
130 DCCP_RESET_CODE_UNSPECIFIED = 0,
131 DCCP_RESET_CODE_CLOSED,
132 DCCP_RESET_CODE_ABORTED,
133 DCCP_RESET_CODE_NO_CONNECTION,
134 DCCP_RESET_CODE_PACKET_ERROR,
135 DCCP_RESET_CODE_OPTION_ERROR,
136 DCCP_RESET_CODE_MANDATORY_ERROR,
137 DCCP_RESET_CODE_CONNECTION_REFUSED,
138 DCCP_RESET_CODE_BAD_SERVICE_CODE,
139 DCCP_RESET_CODE_TOO_BUSY,
140 DCCP_RESET_CODE_BAD_INIT_COOKIE,
141 DCCP_RESET_CODE_AGGRESSION_PENALTY,
142 __DCCP_RESET_CODE_LAST
143 };
144
145 static const char tstr[] = "[|dccp]";
146
147 static const char *dccp_reset_codes[] = {
148 "unspecified",
149 "closed",
150 "aborted",
151 "no_connection",
152 "packet_error",
153 "option_error",
154 "mandatory_error",
155 "connection_refused",
156 "bad_service_code",
157 "too_busy",
158 "bad_init_cookie",
159 "aggression_penalty",
160 };
161
162 static const char *dccp_feature_nums[] = {
163 "reserved",
164 "ccid",
165 "allow_short_seqno",
166 "sequence_window",
167 "ecn_incapable",
168 "ack_ratio",
169 "send_ack_vector",
170 "send_ndp_count",
171 "minimum checksum coverage",
172 "check data checksum",
173 };
174
175 static inline u_int dccp_csum_coverage(const struct dccp_hdr* dh, u_int len)
176 {
177 u_int cov;
178
179 if (DCCPH_CSCOV(dh) == 0)
180 return len;
181 cov = (dh->dccph_doff + DCCPH_CSCOV(dh) - 1) * sizeof(u_int32_t);
182 return (cov > len)? len : cov;
183 }
184
185 static int dccp_cksum(const struct ip *ip,
186 const struct dccp_hdr *dh, u_int len)
187 {
188 return nextproto4_cksum(ip, (const u_int8_t *)(void *)dh, len,
189 dccp_csum_coverage(dh, len), IPPROTO_DCCP);
190 }
191
192 #ifdef INET6
193 static int dccp6_cksum(const struct ip6_hdr *ip6, const struct dccp_hdr *dh, u_int len)
194 {
195 return nextproto6_cksum(ip6, (const u_int8_t *)(void *)dh, len,
196 dccp_csum_coverage(dh, len), IPPROTO_DCCP);
197 }
198 #endif
199
200 static const char *dccp_reset_code(u_int8_t code)
201 {
202 if (code >= __DCCP_RESET_CODE_LAST)
203 return "invalid";
204 return dccp_reset_codes[code];
205 }
206
207 static u_int64_t dccp_seqno(const u_char *bp)
208 {
209 const struct dccp_hdr *dh = (const struct dccp_hdr *)bp;
210 u_int64_t seqno;
211
212 if (DCCPH_X(dh) != 0) {
213 const struct dccp_hdr_ext *dhx = (const struct dccp_hdr_ext *)bp;
214 seqno = EXTRACT_48BITS(dhx->dccph_seq);
215 } else {
216 seqno = EXTRACT_24BITS(dh->dccph_seq);
217 }
218
219 return seqno;
220 }
221
222 static inline unsigned int dccp_basic_hdr_len(const struct dccp_hdr *dh)
223 {
224 return DCCPH_X(dh) ? sizeof(struct dccp_hdr_ext) : sizeof(struct dccp_hdr);
225 }
226
227 static void dccp_print_ack_no(netdissect_options *ndo, const u_char *bp)
228 {
229 const struct dccp_hdr *dh = (const struct dccp_hdr *)bp;
230 const u_char *ackp = bp + dccp_basic_hdr_len(dh);
231 u_int64_t ackno;
232
233 if (DCCPH_X(dh) != 0) {
234 ND_TCHECK2(*ackp, 8);
235 ackno = EXTRACT_48BITS(ackp + 2);
236 } else {
237 ND_TCHECK2(*ackp, 4);
238 ackno = EXTRACT_24BITS(ackp + 1);
239 }
240
241 ND_PRINT((ndo, "(ack=%" PRIu64 ") ", ackno));
242 trunc:
243 return;
244 }
245
246 static int dccp_print_option(netdissect_options *, const u_char *, u_int);
247
248 /**
249 * dccp_print - show dccp packet
250 * @bp - beginning of dccp packet
251 * @data2 - beginning of enclosing
252 * @len - lenght of ip packet
253 */
254 void dccp_print(netdissect_options *ndo, const u_char *bp, const u_char *data2,
255 u_int len)
256 {
257 const struct dccp_hdr *dh;
258 const struct ip *ip;
259 #ifdef INET6
260 const struct ip6_hdr *ip6;
261 #endif
262 const u_char *cp;
263 u_short sport, dport;
264 u_int hlen;
265 u_int fixed_hdrlen;
266
267 dh = (const struct dccp_hdr *)bp;
268
269 ip = (struct ip *)data2;
270 #ifdef INET6
271 if (IP_V(ip) == 6)
272 ip6 = (const struct ip6_hdr *)data2;
273 else
274 ip6 = NULL;
275 #endif /*INET6*/
276
277 /* make sure we have enough data to look at the X bit */
278 cp = (const u_char *)(dh + 1);
279 if (cp > ndo->ndo_snapend) {
280 ND_PRINT((ndo, "[Invalid packet|dccp]"));
281 return;
282 }
283 if (len < sizeof(struct dccp_hdr)) {
284 ND_PRINT((ndo, "truncated-dccp - %u bytes missing!",
285 len - (u_int)sizeof(struct dccp_hdr)));
286 return;
287 }
288
289 /* get the length of the generic header */
290 fixed_hdrlen = dccp_basic_hdr_len(dh);
291 if (len < fixed_hdrlen) {
292 ND_PRINT((ndo, "truncated-dccp - %u bytes missing!",
293 len - fixed_hdrlen));
294 return;
295 }
296 ND_TCHECK2(*dh, fixed_hdrlen);
297
298 sport = EXTRACT_16BITS(&dh->dccph_sport);
299 dport = EXTRACT_16BITS(&dh->dccph_dport);
300 hlen = dh->dccph_doff * 4;
301
302 #ifdef INET6
303 if (ip6) {
304 ND_PRINT((ndo, "%s.%d > %s.%d: ",
305 ip6addr_string(&ip6->ip6_src), sport,
306 ip6addr_string(&ip6->ip6_dst), dport));
307 } else
308 #endif /*INET6*/
309 {
310 ND_PRINT((ndo, "%s.%d > %s.%d: ",
311 ipaddr_string(&ip->ip_src), sport,
312 ipaddr_string(&ip->ip_dst), dport));
313 }
314 fflush(stdout);
315
316 if (ndo->ndo_qflag) {
317 ND_PRINT((ndo, " %d", len - hlen));
318 if (hlen > len) {
319 ND_PRINT((ndo, "dccp [bad hdr length %u - too long, > %u]",
320 hlen, len));
321 }
322 return;
323 }
324
325 /* other variables in generic header */
326 if (ndo->ndo_vflag) {
327 ND_PRINT((ndo, "CCVal %d, CsCov %d, ", DCCPH_CCVAL(dh), DCCPH_CSCOV(dh)));
328 }
329
330 /* checksum calculation */
331 if (ndo->ndo_vflag && ND_TTEST2(bp[0], len)) {
332 u_int16_t sum = 0, dccp_sum;
333
334 dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);
335 ND_PRINT((ndo, "cksum 0x%04x ", dccp_sum));
336 if (IP_V(ip) == 4)
337 sum = dccp_cksum(ip, dh, len);
338 #ifdef INET6
339 else if (IP_V(ip) == 6)
340 sum = dccp6_cksum(ip6, dh, len);
341 #endif
342 if (sum != 0)
343 ND_PRINT((ndo, "(incorrect -> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum)));
344 else
345 ND_PRINT((ndo, "(correct), "));
346 }
347
348 switch (DCCPH_TYPE(dh)) {
349 case DCCP_PKT_REQUEST: {
350 struct dccp_hdr_request *dhr =
351 (struct dccp_hdr_request *)(bp + fixed_hdrlen);
352 fixed_hdrlen += 4;
353 if (len < fixed_hdrlen) {
354 ND_PRINT((ndo, "truncated-dccp request - %u bytes missing!",
355 len - fixed_hdrlen));
356 return;
357 }
358 ND_TCHECK(*dhr);
359 ND_PRINT((ndo, "request (service=%d) ",
360 EXTRACT_32BITS(&dhr->dccph_req_service)));
361 break;
362 }
363 case DCCP_PKT_RESPONSE: {
364 struct dccp_hdr_response *dhr =
365 (struct dccp_hdr_response *)(bp + fixed_hdrlen);
366 fixed_hdrlen += 12;
367 if (len < fixed_hdrlen) {
368 ND_PRINT((ndo, "truncated-dccp response - %u bytes missing!",
369 len - fixed_hdrlen));
370 return;
371 }
372 ND_TCHECK(*dhr);
373 ND_PRINT((ndo, "response (service=%d) ",
374 EXTRACT_32BITS(&dhr->dccph_resp_service)));
375 break;
376 }
377 case DCCP_PKT_DATA:
378 ND_PRINT((ndo, "data "));
379 break;
380 case DCCP_PKT_ACK: {
381 fixed_hdrlen += 8;
382 if (len < fixed_hdrlen) {
383 ND_PRINT((ndo, "truncated-dccp ack - %u bytes missing!",
384 len - fixed_hdrlen));
385 return;
386 }
387 ND_PRINT((ndo, "ack "));
388 break;
389 }
390 case DCCP_PKT_DATAACK: {
391 fixed_hdrlen += 8;
392 if (len < fixed_hdrlen) {
393 ND_PRINT((ndo, "truncated-dccp dataack - %u bytes missing!",
394 len - fixed_hdrlen));
395 return;
396 }
397 ND_PRINT((ndo, "dataack "));
398 break;
399 }
400 case DCCP_PKT_CLOSEREQ:
401 fixed_hdrlen += 8;
402 if (len < fixed_hdrlen) {
403 ND_PRINT((ndo, "truncated-dccp closereq - %u bytes missing!",
404 len - fixed_hdrlen));
405 return;
406 }
407 ND_PRINT((ndo, "closereq "));
408 break;
409 case DCCP_PKT_CLOSE:
410 fixed_hdrlen += 8;
411 if (len < fixed_hdrlen) {
412 ND_PRINT((ndo, "truncated-dccp close - %u bytes missing!",
413 len - fixed_hdrlen));
414 return;
415 }
416 ND_PRINT((ndo, "close "));
417 break;
418 case DCCP_PKT_RESET: {
419 struct dccp_hdr_reset *dhr =
420 (struct dccp_hdr_reset *)(bp + fixed_hdrlen);
421 fixed_hdrlen += 12;
422 if (len < fixed_hdrlen) {
423 ND_PRINT((ndo, "truncated-dccp reset - %u bytes missing!",
424 len - fixed_hdrlen));
425 return;
426 }
427 ND_TCHECK(*dhr);
428 ND_PRINT((ndo, "reset (code=%s) ",
429 dccp_reset_code(dhr->dccph_reset_code)));
430 break;
431 }
432 case DCCP_PKT_SYNC:
433 fixed_hdrlen += 8;
434 if (len < fixed_hdrlen) {
435 ND_PRINT((ndo, "truncated-dccp sync - %u bytes missing!",
436 len - fixed_hdrlen));
437 return;
438 }
439 ND_PRINT((ndo, "sync "));
440 break;
441 case DCCP_PKT_SYNCACK:
442 fixed_hdrlen += 8;
443 if (len < fixed_hdrlen) {
444 ND_PRINT((ndo, "truncated-dccp syncack - %u bytes missing!",
445 len - fixed_hdrlen));
446 return;
447 }
448 ND_PRINT((ndo, "syncack "));
449 break;
450 default:
451 ND_PRINT((ndo, "invalid "));
452 break;
453 }
454
455 if ((DCCPH_TYPE(dh) != DCCP_PKT_DATA) &&
456 (DCCPH_TYPE(dh) != DCCP_PKT_REQUEST))
457 dccp_print_ack_no(ndo, bp);
458
459 if (ndo->ndo_vflag < 2)
460 return;
461
462 ND_PRINT((ndo, "seq %" PRIu64, dccp_seqno(bp)));
463
464 /* process options */
465 if (hlen > fixed_hdrlen){
466 const u_char *cp;
467 u_int optlen;
468 cp = bp + fixed_hdrlen;
469 ND_PRINT((ndo, " <"));
470
471 hlen -= fixed_hdrlen;
472 while(1){
473 optlen = dccp_print_option(ndo, cp, hlen);
474 if (!optlen)
475 break;
476 if (hlen <= optlen)
477 break;
478 hlen -= optlen;
479 cp += optlen;
480 ND_PRINT((ndo, ", "));
481 }
482 ND_PRINT((ndo, ">"));
483 }
484 return;
485 trunc:
486 ND_PRINT((ndo, "%s", tstr));
487 return;
488 }
489
490 static const struct tok dccp_option_values[] = {
491 { 0, "nop" },
492 { 1, "mandatory" },
493 { 2, "slowreceiver" },
494 { 32, "change_l" },
495 { 33, "confirm_l" },
496 { 34, "change_r" },
497 { 35, "confirm_r" },
498 { 36, "initcookie" },
499 { 37, "ndp_count" },
500 { 38, "ack_vector0" },
501 { 39, "ack_vector1" },
502 { 40, "data_dropped" },
503 { 41, "timestamp" },
504 { 42, "timestamp_echo" },
505 { 43, "elapsed_time" },
506 { 44, "data_checksum" },
507 { 0, NULL }
508 };
509
510 static int dccp_print_option(netdissect_options *ndo, const u_char *option, u_int hlen)
511 {
512 u_int8_t optlen, i;
513
514 ND_TCHECK(*option);
515
516 if (*option >= 32) {
517 ND_TCHECK(*(option+1));
518 optlen = *(option +1);
519 if (optlen < 2) {
520 if (*option >= 128)
521 ND_PRINT((ndo, "CCID option %u optlen too short", *option));
522 else
523 ND_PRINT((ndo, "%s optlen too short",
524 tok2str(dccp_option_values, "Option %u", *option)));
525 return 0;
526 }
527 } else
528 optlen = 1;
529
530 if (hlen < optlen) {
531 if (*option >= 128)
532 ND_PRINT((ndo, "CCID option %u optlen goes past header length",
533 *option));
534 else
535 ND_PRINT((ndo, "%s optlen goes past header length",
536 tok2str(dccp_option_values, "Option %u", *option)));
537 return 0;
538 }
539 ND_TCHECK2(*option, optlen);
540
541 if (*option >= 128) {
542 ND_PRINT((ndo, "CCID option %d", *option));
543 switch (optlen) {
544 case 4:
545 ND_PRINT((ndo, " %u", EXTRACT_16BITS(option + 2)));
546 break;
547 case 6:
548 ND_PRINT((ndo, " %u", EXTRACT_32BITS(option + 2)));
549 break;
550 default:
551 break;
552 }
553 } else {
554 ND_PRINT((ndo, "%s", tok2str(dccp_option_values, "Option %u", *option)));
555 switch (*option) {
556 case 32:
557 case 33:
558 case 34:
559 case 35:
560 if (optlen < 3) {
561 ND_PRINT((ndo, " optlen too short"));
562 return optlen;
563 }
564 if (*(option + 2) < 10){
565 ND_PRINT((ndo, " %s", dccp_feature_nums[*(option + 2)]));
566 for (i = 0; i < optlen - 3; i++)
567 ND_PRINT((ndo, " %d", *(option + 3 + i)));
568 }
569 break;
570 case 36:
571 if (optlen > 2) {
572 ND_PRINT((ndo, " 0x"));
573 for (i = 0; i < optlen - 2; i++)
574 ND_PRINT((ndo, "%02x", *(option + 2 + i)));
575 }
576 break;
577 case 37:
578 for (i = 0; i < optlen - 2; i++)
579 ND_PRINT((ndo, " %d", *(option + 2 + i)));
580 break;
581 case 38:
582 if (optlen > 2) {
583 ND_PRINT((ndo, " 0x"));
584 for (i = 0; i < optlen - 2; i++)
585 ND_PRINT((ndo, "%02x", *(option + 2 + i)));
586 }
587 break;
588 case 39:
589 if (optlen > 2) {
590 ND_PRINT((ndo, " 0x"));
591 for (i = 0; i < optlen - 2; i++)
592 ND_PRINT((ndo, "%02x", *(option + 2 + i)));
593 }
594 break;
595 case 40:
596 if (optlen > 2) {
597 ND_PRINT((ndo, " 0x"));
598 for (i = 0; i < optlen - 2; i++)
599 ND_PRINT((ndo, "%02x", *(option + 2 + i)));
600 }
601 break;
602 case 41:
603 if (optlen == 4)
604 ND_PRINT((ndo, " %u", EXTRACT_32BITS(option + 2)));
605 else
606 ND_PRINT((ndo, " optlen != 4"));
607 break;
608 case 42:
609 if (optlen == 4)
610 ND_PRINT((ndo, " %u", EXTRACT_32BITS(option + 2)));
611 else
612 ND_PRINT((ndo, " optlen != 4"));
613 break;
614 case 43:
615 if (optlen == 6)
616 ND_PRINT((ndo, " %u", EXTRACT_32BITS(option + 2)));
617 else if (optlen == 4)
618 ND_PRINT((ndo, " %u", EXTRACT_16BITS(option + 2)));
619 else
620 ND_PRINT((ndo, " optlen != 4 or 6"));
621 break;
622 case 44:
623 if (optlen > 2) {
624 ND_PRINT((ndo, " "));
625 for (i = 0; i < optlen - 2; i++)
626 ND_PRINT((ndo, "%02x", *(option + 2 + i)));
627 }
628 break;
629 }
630 }
631
632 return optlen;
633 trunc:
634 ND_PRINT((ndo, "%s", tstr));
635 return 0;
636 }