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 #ifndef lint
  11 static const char rcsid[] _U_ =
  12     "@(#) $Header: /tcpdump/master/tcpdump/print-dccp.c,v 1.1.2.4 2005-12-05 21:46:37 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
  35 static 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
  50 static 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
  63 static 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
  93 static 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
 136 static 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
 143 static 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
 158 static 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
 163 static 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
 169         TCHECK2(*dh_ack,4);
 170         u_int32_t ack_high = DCCPH_ACK(dh_ack);
 171         u_int64_t ackno = EXTRACT_24BITS(&ack_high) & 0xFFFFFF;
 172
 173         if (DCCPH_X(dh) != 0) {
 174                 TCHECK2(*dh_ack,8);
 175                 u_int32_t ack_low = dh_ack->dccph_ack_nr_low;
 176
 177                 ackno &= 0x00FFFF;  /* clear reserved field */
 178                 ackno = (ackno << 32) + EXTRACT_32BITS(&ack_low);
 179         }
 180
 181         (void)printf("(ack=%" PRIu64 ") ", ackno);
 182 trunc:
 183         return;
 184 }
 185
 186 static inline unsigned int dccp_packet_hdr_len(const u_int8_t type)
 187 {
 188         if (type == DCCP_PKT_DATA)
 189                 return 0;
 190         if (type == DCCP_PKT_DATAACK    ||
 191             type == DCCP_PKT_ACK        ||
 192             type == DCCP_PKT_SYNC       ||
 193             type == DCCP_PKT_SYNCACK    ||
 194             type == DCCP_PKT_CLOSE      ||
 195             type == DCCP_PKT_CLOSEREQ)
 196                 return sizeof(struct dccp_hdr_ack_bits);
 197         if (type == DCCP_PKT_REQUEST)
 198                 return sizeof(struct dccp_hdr_request);
 199         if (type == DCCP_PKT_RESPONSE)
 200                 return sizeof(struct dccp_hdr_response);
 201         return sizeof(struct dccp_hdr_reset);
 202 }
 203
 204 static int dccp_print_option(const u_char *option);
 205
 206 /**
 207  * dccp_print - show dccp packet
 208  * @bp - beginning of dccp packet
 209  * @data2 - beginning of enclosing
 210  * @len - lenght of ip packet
 211  */
 212 void dccp_print(const u_char *bp, const u_char *data2, u_int len)
 213 {
 214         const struct dccp_hdr *dh;
 215         const struct ip *ip;
 216 #ifdef INET6
 217         const struct ip6_hdr *ip6;
 218 #endif
 219         const u_char *cp;
 220         u_short sport, dport;
 221         u_int hlen;
 222         u_int extlen = 0;
 223
 224         dh = (const struct dccp_hdr *)bp;
 225
 226         ip = (struct ip *)data2;
 227 #ifdef INET6
 228         if (IP_V(ip) == 6)
 229                 ip6 = (const struct ip6_hdr *)data2;
 230         else
 231                 ip6 = NULL;
 232 #endif /*INET6*/
 233         cp = (const u_char *)(dh + 1);
 234         if (cp > snapend) {
 235                 printf("[Invalid packet|dccp]");
 236                 return;
 237         }
 238
 239         if (len < sizeof(struct dccp_hdr)) {
 240                 printf("truncated-dccp - %ld bytes missing!",
 241                              (long)len - sizeof(struct dccp_hdr));
 242                 return;
 243         }
 244
 245         sport = EXTRACT_16BITS(&dh->dccph_sport);
 246         dport = EXTRACT_16BITS(&dh->dccph_dport);
 247         hlen = dh->dccph_doff * 4;
 248
 249 #ifdef INET6
 250         if (ip6) {
 251                 (void)printf("%s.%d > %s.%d: ",
 252                              ip6addr_string(&ip6->ip6_src), sport,
 253                              ip6addr_string(&ip6->ip6_dst), dport);
 254         } else
 255 #endif /*INET6*/
 256         {
 257                 (void)printf("%s.%d > %s.%d: ",
 258                              ipaddr_string(&ip->ip_src), sport,
 259                              ipaddr_string(&ip->ip_dst), dport);
 260         }
 261         fflush(stdout);
 262
 263         if (qflag) {
 264                 (void)printf(" %d", len - hlen);
 265                 if (hlen > len) {
 266                         (void)printf("dccp [bad hdr length %u - too long, > %u]",
 267                             hlen, len);
 268                 }
 269                 return;
 270         }
 271
 272         /* other variables in generic header */
 273         if (vflag) {
 274                 (void)printf("CCVal %d, CsCov %d, ", DCCPH_CCVAL(dh), DCCPH_CSCOV(dh));
 275         }
 276
 277         /* checksum calculation */
 278 #ifdef INET6
 279         if (ip6) {
 280                 if (ip6->ip6_plen && vflag) {
 281                         u_int16_t sum, dccp_sum;
 282
 283                         sum = dccp6_cksum(ip6, dh, len);
 284                         dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);
 285                         printf("cksum 0x%04x", dccp_sum);
 286                         if (sum != 0) {
 287                                 (void)printf(" (incorrect (-> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
 288                         } else
 289                                 (void)printf(" (correct), ");
 290                 }
 291         } else
 292 #endif /* INET6 */
 293         if (vflag)
 294         {
 295                 u_int16_t sum, dccp_sum;
 296
 297                 sum = dccp_cksum(ip, dh, len);
 298                 dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);
 299                 printf("cksum 0x%04x", dccp_sum);
 300                 if (sum != 0) {
 301                         (void)printf(" (incorrect (-> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
 302                 } else
 303                         (void)printf(" (correct), ");
 304         }
 305
 306         switch (DCCPH_TYPE(dh)) {
 307         case DCCP_PKT_REQUEST: {
 308                 struct dccp_hdr_request *dhr =
 309                         (struct dccp_hdr_request *)(bp + dccp_basic_hdr_len(dh));
 310                 TCHECK(*dhr);
 311                 (void)printf("request (service=%d) ", dhr->dccph_req_service);
 312                 extlen += 4;
 313                 break;
 314         }
 315         case DCCP_PKT_RESPONSE: {
 316                 struct dccp_hdr_response *dhr =
 317                         (struct dccp_hdr_response *)(bp + dccp_basic_hdr_len(dh));
 318                 TCHECK(*dhr);
 319                 (void)printf("response (service=%d) ", dhr->dccph_resp_service);
 320                 extlen += 12;
 321                 break;
 322         }
 323         case DCCP_PKT_DATA:
 324                 (void)printf("data ");
 325                 break;
 326         case DCCP_PKT_ACK: {
 327                 (void)printf("ack ");
 328                 extlen += 8;
 329                 break;
 330         }
 331         case DCCP_PKT_DATAACK: {
 332                 (void)printf("dataack ");
 333                 extlen += 8;
 334                 break;
 335         }
 336         case DCCP_PKT_CLOSEREQ:
 337                 (void)printf("closereq ");
 338                 extlen += 8;
 339                 break;
 340         case DCCP_PKT_CLOSE:
 341                 (void)printf("close ");
 342                 extlen += 8;
 343                 break;
 344         case DCCP_PKT_RESET: {
 345                 struct dccp_hdr_reset *dhr =
 346                         (struct dccp_hdr_reset *)(bp + dccp_basic_hdr_len(dh));
 347                 TCHECK(*dhr);
 348                 (void)printf("reset (code=%s) ",
 349                              dccp_reset_code(dhr->dccph_reset_code));
 350                 extlen += 12;
 351                 break;
 352         }
 353         case DCCP_PKT_SYNC:
 354                 (void)printf("sync ");
 355                 extlen += 8;
 356                 break;
 357         case DCCP_PKT_SYNCACK:
 358                 (void)printf("syncack ");
 359                 extlen += 8;
 360                 break;
 361         default:
 362                 (void)printf("invalid ");
 363                 break;
 364         }
 365
 366         if ((DCCPH_TYPE(dh) != DCCP_PKT_DATA) &&
 367                         (DCCPH_TYPE(dh) != DCCP_PKT_REQUEST))
 368                 dccp_print_ack_no(bp);
 369
 370         if (vflag < 2)
 371                 return;
 372
 373         (void)printf("seq %" PRIu64, dccp_seqno(dh));
 374
 375         /* process options */
 376         if (hlen > dccp_basic_hdr_len(dh) + extlen){
 377                 const u_char *cp;
 378                 u_int optlen;
 379                 cp = bp + dccp_basic_hdr_len(dh) + extlen;
 380                 printf(" <");
 381
 382                 hlen -= dccp_basic_hdr_len(dh) + extlen;
 383                 while(1){
 384                         TCHECK(*cp);
 385                         optlen = dccp_print_option(cp);
 386                         if (!optlen) goto trunc2;
 387                         if (hlen <= optlen) break;
 388                         hlen -= optlen;
 389                         cp += optlen;
 390                         printf(", ");
 391                 }
 392                 printf(">");
 393         }
 394         return;
 395 trunc:
 396         printf("[|dccp]");
 397 trunc2:
 398         return;
 399 }
 400
 401 static int dccp_print_option(const u_char *option)
 402 {
 403         u_int8_t optlen, i;
 404         u_int32_t *ts;
 405         u_int16_t *var16;
 406         u_int32_t *var32;
 407
 408         TCHECK(*option);
 409
 410         if (*option >= 32) {
 411                 TCHECK(*(option+1));
 412                 optlen = *(option +1);
 413                 if (optlen < 2) {
 414                         printf("Option %d optlen too short",*option);
 415                         return 1;
 416                 }
 417         } else optlen = 1;
 418
 419         TCHECK2(*option,optlen);
 420
 421         switch (*option){
 422         case 0:
 423                 printf("nop");
 424                 break;
 425         case 1:
 426                 printf("mandatory");
 427                 break;
 428         case 2:
 429                 printf("slowreceiver");
 430                 break;
 431         case 32:
 432                 printf("change_l");
 433                 if (*(option +2) < 10){
 434                         printf(" %s", dccp_feature_nums[*(option +2)]);
 435                         for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
 436                 }
 437                 break;
 438         case 33:
 439                 printf("confirm_l");
 440                 if (*(option +2) < 10){
 441                         printf(" %s", dccp_feature_nums[*(option +2)]);
 442                         for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
 443                 }
 444                 break;
 445         case 34:
 446                 printf("change_r");
 447                 if (*(option +2) < 10){
 448                         printf(" %s", dccp_feature_nums[*(option +2)]);
 449                         for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
 450                 }
 451                 break;
 452         case 35:
 453                 printf("confirm_r");
 454                 if (*(option +2) < 10){
 455                         printf(" %s", dccp_feature_nums[*(option +2)]);
 456                         for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
 457                 }
 458                 break;
 459         case 36:
 460                 printf("initcookie 0x");
 461                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 462                 break;
 463         case 37:
 464                 printf("ndp_count");
 465                 for (i = 0; i < optlen -2; i ++) printf(" %d", *(option +2 + i));
 466                 break;
 467         case 38:
 468                 printf("ack_vector0 0x");
 469                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 470                 break;
 471         case 39:
 472                 printf("ack_vector1 0x");
 473                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 474                 break;
 475         case 40:
 476                 printf("data_dropped 0x");
 477                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 478                 break;
 479         case 41:
 480                 ts = (u_int32_t *)(option + 2);
 481                 printf("timestamp %u", (u_int32_t)ntohl(*ts));
 482                 break;
 483         case 42:
 484                 ts = (u_int32_t *)(option + 2);
 485                 printf("timestamp_echo %u", (u_int32_t)ntohl(*ts));
 486                 break;
 487         case 43:
 488                 printf("elapsed_time ");
 489                 if (optlen == 6){
 490                         ts = (u_int32_t *)(option + 2);
 491                         printf("%u", (u_int32_t)ntohl(*ts));
 492                 } else {
 493                         var16 = (u_int16_t *)(option + 2);
 494                         printf("%u", ntohs(*var16));
 495                 }
 496                 break;
 497         case 44:
 498                 printf("data_checksum ");
 499                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 500                 break;
 501         default :
 502                 if (*option >= 128) {
 503                         printf("CCID option %d",*option);
 504                         switch (optlen) {
 505                                 case 4:
 506                                         var16 = (u_int16_t *)(option + 2);
 507                                         printf(" %u",ntohs(*var16));
 508                                         break;
 509                                 case 6:
 510                                         var32 = (u_int32_t *)(option + 2);
 511                                         printf(" %u",(u_int32_t)ntohl(*var32));
 512                                         break;
 513                                 default:
 514                                         break;
 515                         }
 516                         break;
 517                 }
 518
 519                 printf("unknown_opt %d", *option);
 520                 break;
 521         }
 522
 523         return optlen;
 524 trunc:
 525         printf("[|dccp]");
 526         return 0;
 527 }