The Tcpdump Group git mirrors - tcpdump/blob - 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
  30  *
  31  * @dccph_sport - Relevant port on the endpoint that sent this packet
  32  * @dccph_dport - Relevant port on the other endpoint
  33  * @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words
  34  * @dccph_ccval - Used by the HC-Sender CCID
  35  * @dccph_cscov - Parts of the packet that are covered by the Checksum field
  36  * @dccph_checksum - Internet checksum, depends on dccph_cscov
  37  * @dccph_x - 0 = 24 bit sequence number, 1 = 48
  38  * @dccph_type - packet type, see DCCP_PKT_ prefixed macros
  39  * @dccph_seq - sequence number high or low order 24 bits, depends on dccph_x
  40  */
  41 struct dccp_hdr {
  42         u_int16_t       dccph_sport,
  43                         dccph_dport;
  44         u_int8_t        dccph_doff;
  45         u_int8_t        dccph_ccval_cscov;
  46         u_int16_t       dccph_checksum;
  47         union {
  48         u_int8_t        dccph_xtr;
  49         u_int32_t       dccph_seq;
  50         }               dccph_xtrs;
  51 } UNALIGNED;
  52
  53 #define DCCPH_CCVAL(dh) (((dh)->dccph_ccval_cscov >> 4) & 0xF)
  54 #define DCCPH_CSCOV(dh) (((dh)->dccph_ccval_cscov) & 0xF)
  55
  56 #define DCCPH_X(dh)     ((dh)->dccph_xtrs.dccph_xtr & 1)
  57 #define DCCPH_TYPE(dh)  (((dh)->dccph_xtrs.dccph_xtr >> 1) & 0xF)
  58 #define DCCPH_SEQ(dh)   (((dh)->dccph_xtrs.dccph_seq) >> 8)
  59
  60 /**
  61  * struct dccp_hdr_ext - the low bits of a 48 bit seq packet
  62  *
  63  * @dccph_seq_low - low 24 bits of a 48 bit seq packet
  64  */
  65 struct dccp_hdr_ext {
  66         u_int32_t       dccph_seq_low;
  67 } UNALIGNED;
  68
  69 /**
  70  * struct dccp_hdr_request - Conection initiation request header
  71  *
  72  * @dccph_req_service - Service to which the client app wants to connect
  73  */
  74 struct dccp_hdr_request {
  75         u_int32_t       dccph_req_service;
  76 } UNALIGNED;
  77
  78 /**
  79  * struct dccp_hdr_ack_bits - acknowledgment bits common to most packets
  80  *
  81  * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
  82  * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
  83  */
  84 struct dccp_hdr_ack_bits {
  85         u_int32_t       dccph_ra;
  86         u_int32_t       dccph_ack_nr_low;
  87 } UNALIGNED;
  88
  89 #define DCCPH_ACK(dh_ack)   ((dh_ack)->dccph_ra >> 8)
  90
  91 /**
  92  * struct dccp_hdr_response - Conection initiation response header
  93  *
  94  * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
  95  * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
  96  * @dccph_resp_service - Echoes the Service Code on a received DCCP-Request
  97  */
  98 struct dccp_hdr_response {
  99         struct dccp_hdr_ack_bits        dccph_resp_ack;
 100         u_int32_t                       dccph_resp_service;
 101 } UNALIGNED;
 102
 103 /**
 104  * struct dccp_hdr_reset - Unconditionally shut down a connection
 105  *
 106  * @dccph_reset_service - Echoes the Service Code on a received DCCP-Request
 107  */
 108 struct dccp_hdr_reset {
 109         struct dccp_hdr_ack_bits        dccph_reset_ack;
 110         u_int8_t                        dccph_reset_code,
 111                                         dccph_reset_data[3];
 112 } UNALIGNED;
 113
 114 enum dccp_pkt_type {
 115         DCCP_PKT_REQUEST = 0,
 116         DCCP_PKT_RESPONSE,
 117         DCCP_PKT_DATA,
 118         DCCP_PKT_ACK,
 119         DCCP_PKT_DATAACK,
 120         DCCP_PKT_CLOSEREQ,
 121         DCCP_PKT_CLOSE,
 122         DCCP_PKT_RESET,
 123         DCCP_PKT_SYNC,
 124         DCCP_PKT_SYNCACK,
 125         DCCP_PKT_INVALID
 126 };
 127
 128 enum dccp_reset_codes {
 129         DCCP_RESET_CODE_UNSPECIFIED = 0,
 130         DCCP_RESET_CODE_CLOSED,
 131         DCCP_RESET_CODE_ABORTED,
 132         DCCP_RESET_CODE_NO_CONNECTION,
 133         DCCP_RESET_CODE_PACKET_ERROR,
 134         DCCP_RESET_CODE_OPTION_ERROR,
 135         DCCP_RESET_CODE_MANDATORY_ERROR,
 136         DCCP_RESET_CODE_CONNECTION_REFUSED,
 137         DCCP_RESET_CODE_BAD_SERVICE_CODE,
 138         DCCP_RESET_CODE_TOO_BUSY,
 139         DCCP_RESET_CODE_BAD_INIT_COOKIE,
 140         DCCP_RESET_CODE_AGGRESSION_PENALTY,
 141         __DCCP_RESET_CODE_LAST
 142 };
 143
 144 static const char tstr[] = "[|dccp]";
 145
 146 static const char *dccp_reset_codes[] = {
 147         "unspecified",
 148         "closed",
 149         "aborted",
 150         "no_connection",
 151         "packet_error",
 152         "option_error",
 153         "mandatory_error",
 154         "connection_refused",
 155         "bad_service_code",
 156         "too_busy",
 157         "bad_init_cookie",
 158         "aggression_penalty",
 159 };
 160
 161 static const char *dccp_feature_nums[] = {
 162         "reserved",
 163         "ccid",
 164         "allow_short_seqno",
 165         "sequence_window",
 166         "ecn_incapable",
 167         "ack_ratio",
 168         "send_ack_vector",
 169         "send_ndp_count",
 170         "minimum checksum coverage",
 171         "check data checksum",
 172 };
 173
 174 static inline u_int dccp_csum_coverage(const struct dccp_hdr* dh, u_int len)
 175 {
 176         u_int cov;
 177
 178         if (DCCPH_CSCOV(dh) == 0)
 179                 return len;
 180         cov = (dh->dccph_doff + DCCPH_CSCOV(dh) - 1) * sizeof(u_int32_t);
 181         return (cov > len)? len : cov;
 182 }
 183
 184 static int dccp_cksum(const struct ip *ip,
 185         const struct dccp_hdr *dh, u_int len)
 186 {
 187         return nextproto4_cksum(ip, (const u_int8_t *)(void *)dh, len,
 188                                 dccp_csum_coverage(dh, len), IPPROTO_DCCP);
 189 }
 190
 191 #ifdef INET6
 192 static int dccp6_cksum(const struct ip6_hdr *ip6, const struct dccp_hdr *dh, u_int len)
 193 {
 194         return nextproto6_cksum(ip6, (const u_int8_t *)(void *)dh,
 195             dccp_csum_coverage(dh, len), IPPROTO_DCCP);
 196 }
 197 #endif
 198
 199 static const char *dccp_reset_code(u_int8_t code)
 200 {
 201         if (code >= __DCCP_RESET_CODE_LAST)
 202                 return "invalid";
 203         return dccp_reset_codes[code];
 204 }
 205
 206 static u_int64_t dccp_seqno(const struct dccp_hdr *dh)
 207 {
 208         u_int32_t seq_high = DCCPH_SEQ(dh);
 209         u_int64_t seqno = EXTRACT_24BITS(&seq_high) & 0xFFFFFF;
 210
 211         if (DCCPH_X(dh) != 0) {
 212                 const struct dccp_hdr_ext *dhx = (void *)(dh + 1);
 213                 u_int32_t seq_low = dhx->dccph_seq_low;
 214                 seqno &= 0x00FFFF;  /* clear reserved field */
 215                 seqno = (seqno << 32) + EXTRACT_32BITS(&seq_low);
 216         }
 217
 218         return seqno;
 219 }
 220
 221 static inline unsigned int dccp_basic_hdr_len(const struct dccp_hdr *dh)
 222 {
 223         return sizeof(*dh) + (DCCPH_X(dh) ? sizeof(struct dccp_hdr_ext) : 0);
 224 }
 225
 226 static void dccp_print_ack_no(const u_char *bp)
 227 {
 228         const struct dccp_hdr *dh = (const struct dccp_hdr *)bp;
 229         const u_char *ackp = bp + dccp_basic_hdr_len(dh);
 230         u_int64_t ackno;
 231
 232         if (DCCPH_X(dh) != 0) {
 233                 TCHECK2(*ackp, 8);
 234                 ackno = EXTRACT_48BITS(ackp + 2);
 235         } else {
 236                 TCHECK2(*ackp, 4);
 237                 ackno = EXTRACT_24BITS(ackp + 1);
 238         }
 239
 240         (void)printf("(ack=%" PRIu64 ") ", ackno);
 241 trunc:
 242         return;
 243 }
 244
 245 static inline unsigned int dccp_packet_hdr_len(const u_int8_t type)
 246 {
 247         if (type == DCCP_PKT_DATA)
 248                 return 0;
 249         if (type == DCCP_PKT_DATAACK    ||
 250             type == DCCP_PKT_ACK        ||
 251             type == DCCP_PKT_SYNC       ||
 252             type == DCCP_PKT_SYNCACK    ||
 253             type == DCCP_PKT_CLOSE      ||
 254             type == DCCP_PKT_CLOSEREQ)
 255                 return sizeof(struct dccp_hdr_ack_bits);
 256         if (type == DCCP_PKT_REQUEST)
 257                 return sizeof(struct dccp_hdr_request);
 258         if (type == DCCP_PKT_RESPONSE)
 259                 return sizeof(struct dccp_hdr_response);
 260         return sizeof(struct dccp_hdr_reset);
 261 }
 262
 263 static int dccp_print_option(const u_char *option);
 264
 265 /**
 266  * dccp_print - show dccp packet
 267  * @bp - beginning of dccp packet
 268  * @data2 - beginning of enclosing
 269  * @len - lenght of ip packet
 270  */
 271 void dccp_print(const u_char *bp, const u_char *data2, u_int len)
 272 {
 273         const struct dccp_hdr *dh;
 274         const struct ip *ip;
 275 #ifdef INET6
 276         const struct ip6_hdr *ip6;
 277 #endif
 278         const u_char *cp;
 279         u_short sport, dport;
 280         u_int hlen;
 281         u_int extlen = 0;
 282
 283         dh = (const struct dccp_hdr *)bp;
 284
 285         ip = (struct ip *)data2;
 286 #ifdef INET6
 287         if (IP_V(ip) == 6)
 288                 ip6 = (const struct ip6_hdr *)data2;
 289         else
 290                 ip6 = NULL;
 291 #endif /*INET6*/
 292         cp = (const u_char *)(dh + 1);
 293         if (cp > snapend) {
 294                 printf("[Invalid packet|dccp]");
 295                 return;
 296         }
 297
 298         if (len < sizeof(struct dccp_hdr)) {
 299                 printf("truncated-dccp - %ld bytes missing!",
 300                              (long)len - sizeof(struct dccp_hdr));
 301                 return;
 302         }
 303
 304         sport = EXTRACT_16BITS(&dh->dccph_sport);
 305         dport = EXTRACT_16BITS(&dh->dccph_dport);
 306         hlen = dh->dccph_doff * 4;
 307
 308 #ifdef INET6
 309         if (ip6) {
 310                 (void)printf("%s.%d > %s.%d: ",
 311                              ip6addr_string(&ip6->ip6_src), sport,
 312                              ip6addr_string(&ip6->ip6_dst), dport);
 313         } else
 314 #endif /*INET6*/
 315         {
 316                 (void)printf("%s.%d > %s.%d: ",
 317                              ipaddr_string(&ip->ip_src), sport,
 318                              ipaddr_string(&ip->ip_dst), dport);
 319         }
 320         fflush(stdout);
 321
 322         if (qflag) {
 323                 (void)printf(" %d", len - hlen);
 324                 if (hlen > len) {
 325                         (void)printf("dccp [bad hdr length %u - too long, > %u]",
 326                             hlen, len);
 327                 }
 328                 return;
 329         }
 330
 331         /* other variables in generic header */
 332         if (vflag) {
 333                 (void)printf("CCVal %d, CsCov %d, ", DCCPH_CCVAL(dh), DCCPH_CSCOV(dh));
 334         }
 335
 336         /* checksum calculation */
 337         if (vflag && TTEST2(bp[0], len)) {
 338                 u_int16_t sum = 0, dccp_sum;
 339
 340                 dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);
 341                 (void)printf("cksum 0x%04x ", dccp_sum);
 342                 if (IP_V(ip) == 4)
 343                         sum = dccp_cksum(ip, dh, len);
 344 #ifdef INET6
 345                 else if (IP_V(ip) == 6)
 346                         sum = dccp6_cksum(ip6, dh, len);
 347 #endif
 348                 if (sum != 0)
 349                         (void)printf("(incorrect -> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
 350                 else
 351                         (void)printf("(correct), ");
 352         }
 353
 354         switch (DCCPH_TYPE(dh)) {
 355         case DCCP_PKT_REQUEST: {
 356                 struct dccp_hdr_request *dhr =
 357                         (struct dccp_hdr_request *)(bp + dccp_basic_hdr_len(dh));
 358                 TCHECK(*dhr);
 359                 (void)printf("request (service=%d) ",
 360                              EXTRACT_32BITS(&dhr->dccph_req_service));
 361                 extlen += 4;
 362                 break;
 363         }
 364         case DCCP_PKT_RESPONSE: {
 365                 struct dccp_hdr_response *dhr =
 366                         (struct dccp_hdr_response *)(bp + dccp_basic_hdr_len(dh));
 367                 TCHECK(*dhr);
 368                 (void)printf("response (service=%d) ",
 369                              EXTRACT_32BITS(&dhr->dccph_resp_service));
 370                 extlen += 12;
 371                 break;
 372         }
 373         case DCCP_PKT_DATA:
 374                 (void)printf("data ");
 375                 break;
 376         case DCCP_PKT_ACK: {
 377                 (void)printf("ack ");
 378                 extlen += 8;
 379                 break;
 380         }
 381         case DCCP_PKT_DATAACK: {
 382                 (void)printf("dataack ");
 383                 extlen += 8;
 384                 break;
 385         }
 386         case DCCP_PKT_CLOSEREQ:
 387                 (void)printf("closereq ");
 388                 extlen += 8;
 389                 break;
 390         case DCCP_PKT_CLOSE:
 391                 (void)printf("close ");
 392                 extlen += 8;
 393                 break;
 394         case DCCP_PKT_RESET: {
 395                 struct dccp_hdr_reset *dhr =
 396                         (struct dccp_hdr_reset *)(bp + dccp_basic_hdr_len(dh));
 397                 TCHECK(*dhr);
 398                 (void)printf("reset (code=%s) ",
 399                              dccp_reset_code(dhr->dccph_reset_code));
 400                 extlen += 12;
 401                 break;
 402         }
 403         case DCCP_PKT_SYNC:
 404                 (void)printf("sync ");
 405                 extlen += 8;
 406                 break;
 407         case DCCP_PKT_SYNCACK:
 408                 (void)printf("syncack ");
 409                 extlen += 8;
 410                 break;
 411         default:
 412                 (void)printf("invalid ");
 413                 break;
 414         }
 415
 416         if ((DCCPH_TYPE(dh) != DCCP_PKT_DATA) &&
 417                         (DCCPH_TYPE(dh) != DCCP_PKT_REQUEST))
 418                 dccp_print_ack_no(bp);
 419
 420         if (vflag < 2)
 421                 return;
 422
 423         (void)printf("seq %" PRIu64, dccp_seqno(dh));
 424
 425         /* process options */
 426         if (hlen > dccp_basic_hdr_len(dh) + extlen){
 427                 const u_char *cp;
 428                 u_int optlen;
 429                 cp = bp + dccp_basic_hdr_len(dh) + extlen;
 430                 printf(" <");
 431
 432                 hlen -= dccp_basic_hdr_len(dh) + extlen;
 433                 while(1){
 434                         TCHECK(*cp);
 435                         optlen = dccp_print_option(cp);
 436                         if (!optlen) goto trunc2;
 437                         if (hlen <= optlen) break;
 438                         hlen -= optlen;
 439                         cp += optlen;
 440                         printf(", ");
 441                 }
 442                 printf(">");
 443         }
 444         return;
 445 trunc:
 446         printf("%s", tstr);
 447 trunc2:
 448         return;
 449 }
 450
 451 static int dccp_print_option(const u_char *option)
 452 {
 453         u_int8_t optlen, i;
 454
 455         TCHECK(*option);
 456
 457         if (*option >= 32) {
 458                 TCHECK(*(option+1));
 459                 optlen = *(option +1);
 460                 if (optlen < 2) {
 461                         printf("Option %d optlen too short",*option);
 462                         return 1;
 463                 }
 464         } else optlen = 1;
 465
 466         TCHECK2(*option,optlen);
 467
 468         switch (*option){
 469         case 0:
 470                 printf("nop");
 471                 break;
 472         case 1:
 473                 printf("mandatory");
 474                 break;
 475         case 2:
 476                 printf("slowreceiver");
 477                 break;
 478         case 32:
 479                 printf("change_l");
 480                 if (*(option +2) < 10){
 481                         printf(" %s", dccp_feature_nums[*(option +2)]);
 482                         for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
 483                 }
 484                 break;
 485         case 33:
 486                 printf("confirm_l");
 487                 if (*(option +2) < 10){
 488                         printf(" %s", dccp_feature_nums[*(option +2)]);
 489                         for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
 490                 }
 491                 break;
 492         case 34:
 493                 printf("change_r");
 494                 if (*(option +2) < 10){
 495                         printf(" %s", dccp_feature_nums[*(option +2)]);
 496                         for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
 497                 }
 498                 break;
 499         case 35:
 500                 printf("confirm_r");
 501                 if (*(option +2) < 10){
 502                         printf(" %s", dccp_feature_nums[*(option +2)]);
 503                         for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
 504                 }
 505                 break;
 506         case 36:
 507                 printf("initcookie 0x");
 508                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 509                 break;
 510         case 37:
 511                 printf("ndp_count");
 512                 for (i = 0; i < optlen -2; i ++) printf(" %d", *(option +2 + i));
 513                 break;
 514         case 38:
 515                 printf("ack_vector0 0x");
 516                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 517                 break;
 518         case 39:
 519                 printf("ack_vector1 0x");
 520                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 521                 break;
 522         case 40:
 523                 printf("data_dropped 0x");
 524                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 525                 break;
 526         case 41:
 527                 printf("timestamp %u", EXTRACT_32BITS(option + 2));
 528                 break;
 529         case 42:
 530                 printf("timestamp_echo %u", EXTRACT_32BITS(option + 2));
 531                 break;
 532         case 43:
 533                 printf("elapsed_time ");
 534                 if (optlen == 6)
 535                         printf("%u", EXTRACT_32BITS(option + 2));
 536                 else
 537                         printf("%u", EXTRACT_16BITS(option + 2));
 538                 break;
 539         case 44:
 540                 printf("data_checksum ");
 541                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 542                 break;
 543         default :
 544                 if (*option >= 128) {
 545                         printf("CCID option %d",*option);
 546                         switch (optlen) {
 547                                 case 4:
 548                                         printf(" %u", EXTRACT_16BITS(option + 2));
 549                                         break;
 550                                 case 6:
 551                                         printf(" %u", EXTRACT_32BITS(option + 2));
 552                                         break;
 553                                 default:
 554                                         break;
 555                         }
 556                         break;
 557                 }
 558
 559                 printf("unknown_opt %d", *option);
 560                 break;
 561         }
 562
 563         return optlen;
 564 trunc:
 565         printf("%s", tstr);
 566         return 0;
 567 }