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[FreeBSD/FreeBSD.git] / contrib / 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 #define NETDISSECT_REWORKED
11 #ifdef HAVE_CONFIG_H
12 #include "config.h"
13 #endif
14
15 #include <tcpdump-stdinc.h>
16
17 #include <stdio.h>
18 #include <string.h>
19
20 #include "interface.h"
21 #include "addrtoname.h"
22 #include "extract.h"                    /* must come after interface.h */
23 #include "ip.h"
24 #ifdef INET6
25 #include "ip6.h"
26 #endif
27 #include "ipproto.h"
28
29 /**
30  * struct dccp_hdr - generic part of DCCP packet header, with a 24-bit
31  * sequence number
32  *
33  * @dccph_sport - Relevant port on the endpoint that sent this packet
34  * @dccph_dport - Relevant port on the other endpoint
35  * @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words
36  * @dccph_ccval - Used by the HC-Sender CCID
37  * @dccph_cscov - Parts of the packet that are covered by the Checksum field
38  * @dccph_checksum - Internet checksum, depends on dccph_cscov
39  * @dccph_x - 0 = 24 bit sequence number, 1 = 48
40  * @dccph_type - packet type, see DCCP_PKT_ prefixed macros
41  * @dccph_seq - 24-bit sequence number
42  */
43 struct dccp_hdr {
44         uint16_t        dccph_sport,
45                         dccph_dport;
46         uint8_t         dccph_doff;
47         uint8_t         dccph_ccval_cscov;
48         uint16_t        dccph_checksum;
49         uint8_t         dccph_xtr;
50         uint8_t         dccph_seq[3];
51 } UNALIGNED;
52
53 /**
54  * struct dccp_hdr_ext - generic part of DCCP packet header, with a 48-bit
55  * sequence number
56  *
57  * @dccph_sport - Relevant port on the endpoint that sent this packet
58  * @dccph_dport - Relevant port on the other endpoint
59  * @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words
60  * @dccph_ccval - Used by the HC-Sender CCID
61  * @dccph_cscov - Parts of the packet that are covered by the Checksum field
62  * @dccph_checksum - Internet checksum, depends on dccph_cscov
63  * @dccph_x - 0 = 24 bit sequence number, 1 = 48
64  * @dccph_type - packet type, see DCCP_PKT_ prefixed macros
65  * @dccph_seq - 48-bit sequence number
66  */
67 struct dccp_hdr_ext {
68         uint16_t        dccph_sport,
69                         dccph_dport;
70         uint8_t         dccph_doff;
71         uint8_t         dccph_ccval_cscov;
72         uint16_t        dccph_checksum;
73         uint8_t         dccph_xtr;
74         uint8_t         reserved;
75         uint8_t         dccph_seq[6];
76 } UNALIGNED;
77
78 #define DCCPH_CCVAL(dh) (((dh)->dccph_ccval_cscov >> 4) & 0xF)
79 #define DCCPH_CSCOV(dh) (((dh)->dccph_ccval_cscov) & 0xF)
80
81 #define DCCPH_X(dh)     ((dh)->dccph_xtr & 1)
82 #define DCCPH_TYPE(dh)  (((dh)->dccph_xtr >> 1) & 0xF)
83
84 /**
85  * struct dccp_hdr_request - Conection initiation request header
86  *
87  * @dccph_req_service - Service to which the client app wants to connect
88  */
89 struct dccp_hdr_request {
90         uint32_t        dccph_req_service;
91 } UNALIGNED;
92
93 /**
94  * struct dccp_hdr_response - Conection initiation response header
95  *
96  * @dccph_resp_ack - 48 bit ack number, contains GSR
97  * @dccph_resp_service - Echoes the Service Code on a received DCCP-Request
98  */
99 struct dccp_hdr_response {
100         uint8_t                         dccph_resp_ack[8];      /* always 8 bytes */
101         uint32_t                        dccph_resp_service;
102 } UNALIGNED;
103
104 /**
105  * struct dccp_hdr_reset - Unconditionally shut down a connection
106  *
107  * @dccph_resp_ack - 48 bit ack number
108  * @dccph_reset_service - Echoes the Service Code on a received DCCP-Request
109  */
110 struct dccp_hdr_reset {
111         uint8_t                         dccph_reset_ack[8];     /* always 8 bytes */
112         uint8_t                         dccph_reset_code,
113                                         dccph_reset_data[3];
114 } UNALIGNED;
115
116 enum dccp_pkt_type {
117         DCCP_PKT_REQUEST = 0,
118         DCCP_PKT_RESPONSE,
119         DCCP_PKT_DATA,
120         DCCP_PKT_ACK,
121         DCCP_PKT_DATAACK,
122         DCCP_PKT_CLOSEREQ,
123         DCCP_PKT_CLOSE,
124         DCCP_PKT_RESET,
125         DCCP_PKT_SYNC,
126         DCCP_PKT_SYNCACK,
127         DCCP_PKT_INVALID
128 };
129
130 enum dccp_reset_codes {
131         DCCP_RESET_CODE_UNSPECIFIED = 0,
132         DCCP_RESET_CODE_CLOSED,
133         DCCP_RESET_CODE_ABORTED,
134         DCCP_RESET_CODE_NO_CONNECTION,
135         DCCP_RESET_CODE_PACKET_ERROR,
136         DCCP_RESET_CODE_OPTION_ERROR,
137         DCCP_RESET_CODE_MANDATORY_ERROR,
138         DCCP_RESET_CODE_CONNECTION_REFUSED,
139         DCCP_RESET_CODE_BAD_SERVICE_CODE,
140         DCCP_RESET_CODE_TOO_BUSY,
141         DCCP_RESET_CODE_BAD_INIT_COOKIE,
142         DCCP_RESET_CODE_AGGRESSION_PENALTY,
143         __DCCP_RESET_CODE_LAST
144 };
145
146 static const char tstr[] = "[|dccp]";
147
148 static const char *dccp_reset_codes[] = {
149         "unspecified",
150         "closed",
151         "aborted",
152         "no_connection",
153         "packet_error",
154         "option_error",
155         "mandatory_error",
156         "connection_refused",
157         "bad_service_code",
158         "too_busy",
159         "bad_init_cookie",
160         "aggression_penalty",
161 };
162
163 static const char *dccp_feature_nums[] = {
164         "reserved",
165         "ccid",
166         "allow_short_seqno",
167         "sequence_window",
168         "ecn_incapable",
169         "ack_ratio",
170         "send_ack_vector",
171         "send_ndp_count",
172         "minimum checksum coverage",
173         "check data checksum",
174 };
175
176 static inline u_int dccp_csum_coverage(const struct dccp_hdr* dh, u_int len)
177 {
178         u_int cov;
179
180         if (DCCPH_CSCOV(dh) == 0)
181                 return len;
182         cov = (dh->dccph_doff + DCCPH_CSCOV(dh) - 1) * sizeof(uint32_t);
183         return (cov > len)? len : cov;
184 }
185
186 static int dccp_cksum(netdissect_options *ndo, const struct ip *ip,
187         const struct dccp_hdr *dh, u_int len)
188 {
189         return nextproto4_cksum(ndo, ip, (const uint8_t *)(void *)dh, len,
190                                 dccp_csum_coverage(dh, len), IPPROTO_DCCP);
191 }
192
193 #ifdef INET6
194 static int dccp6_cksum(const struct ip6_hdr *ip6, const struct dccp_hdr *dh, u_int len)
195 {
196         return nextproto6_cksum(ip6, (const uint8_t *)(void *)dh, len,
197                                 dccp_csum_coverage(dh, len), IPPROTO_DCCP);
198 }
199 #endif
200
201 static const char *dccp_reset_code(uint8_t code)
202 {
203         if (code >= __DCCP_RESET_CODE_LAST)
204                 return "invalid";
205         return dccp_reset_codes[code];
206 }
207
208 static uint64_t dccp_seqno(const u_char *bp)
209 {
210         const struct dccp_hdr *dh = (const struct dccp_hdr *)bp;
211         uint64_t seqno;
212
213         if (DCCPH_X(dh) != 0) {
214                 const struct dccp_hdr_ext *dhx = (const struct dccp_hdr_ext *)bp;
215                 seqno = EXTRACT_48BITS(dhx->dccph_seq);
216         } else {
217                 seqno = EXTRACT_24BITS(dh->dccph_seq);
218         }
219
220         return seqno;
221 }
222
223 static inline unsigned int dccp_basic_hdr_len(const struct dccp_hdr *dh)
224 {
225         return DCCPH_X(dh) ? sizeof(struct dccp_hdr_ext) : sizeof(struct dccp_hdr);
226 }
227
228 static void dccp_print_ack_no(netdissect_options *ndo, const u_char *bp)
229 {
230         const struct dccp_hdr *dh = (const struct dccp_hdr *)bp;
231         const u_char *ackp = bp + dccp_basic_hdr_len(dh);
232         uint64_t ackno;
233
234         if (DCCPH_X(dh) != 0) {
235                 ND_TCHECK2(*ackp, 8);
236                 ackno = EXTRACT_48BITS(ackp + 2);
237         } else {
238                 ND_TCHECK2(*ackp, 4);
239                 ackno = EXTRACT_24BITS(ackp + 1);
240         }
241
242         ND_PRINT((ndo, "(ack=%" PRIu64 ") ", ackno));
243 trunc:
244         return;
245 }
246
247 static int dccp_print_option(netdissect_options *, const u_char *, u_int);
248
249 /**
250  * dccp_print - show dccp packet
251  * @bp - beginning of dccp packet
252  * @data2 - beginning of enclosing
253  * @len - lenght of ip packet
254  */
255 void dccp_print(netdissect_options *ndo, const u_char *bp, const u_char *data2,
256                 u_int len)
257 {
258         const struct dccp_hdr *dh;
259         const struct ip *ip;
260 #ifdef INET6
261         const struct ip6_hdr *ip6;
262 #endif
263         const u_char *cp;
264         u_short sport, dport;
265         u_int hlen;
266         u_int fixed_hdrlen;
267
268         dh = (const struct dccp_hdr *)bp;
269
270         ip = (struct ip *)data2;
271 #ifdef INET6
272         if (IP_V(ip) == 6)
273                 ip6 = (const struct ip6_hdr *)data2;
274         else
275                 ip6 = NULL;
276 #endif /*INET6*/
277
278         /* make sure we have enough data to look at the X bit */
279         cp = (const u_char *)(dh + 1);
280         if (cp > ndo->ndo_snapend) {
281                 ND_PRINT((ndo, "[Invalid packet|dccp]"));
282                 return;
283         }
284         if (len < sizeof(struct dccp_hdr)) {
285                 ND_PRINT((ndo, "truncated-dccp - %u bytes missing!",
286                              len - (u_int)sizeof(struct dccp_hdr)));
287                 return;
288         }
289
290         /* get the length of the generic header */
291         fixed_hdrlen = dccp_basic_hdr_len(dh);
292         if (len < fixed_hdrlen) {
293                 ND_PRINT((ndo, "truncated-dccp - %u bytes missing!",
294                              len - fixed_hdrlen));
295                 return;
296         }
297         ND_TCHECK2(*dh, fixed_hdrlen);
298
299         sport = EXTRACT_16BITS(&dh->dccph_sport);
300         dport = EXTRACT_16BITS(&dh->dccph_dport);
301         hlen = dh->dccph_doff * 4;
302
303 #ifdef INET6
304         if (ip6) {
305                 ND_PRINT((ndo, "%s.%d > %s.%d: ",
306                              ip6addr_string(ndo, &ip6->ip6_src), sport,
307                              ip6addr_string(ndo, &ip6->ip6_dst), dport));
308         } else
309 #endif /*INET6*/
310         {
311                 ND_PRINT((ndo, "%s.%d > %s.%d: ",
312                              ipaddr_string(ndo, &ip->ip_src), sport,
313                              ipaddr_string(ndo, &ip->ip_dst), dport));
314         }
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                 uint16_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(ndo, 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         uint8_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 }