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 1.1.2.2 2005-09-20 06:25:45 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 + sizeof(*dh);
 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 u_int64_t dccp_ack_no(const struct dccp_hdr *dh,
 159                 const struct dccp_hdr_ack_bits *dh_ack)
 160 {
 161         u_int32_t ack_high = DCCPH_ACK(dh_ack);
 162         u_int64_t ackno = EXTRACT_24BITS(&ack_high) & 0xFFFFFF;
 163
 164         if (DCCPH_X(dh) != 0) {
 165                 u_int32_t ack_low = dh_ack->dccph_ack_nr_low;
 166
 167                 ackno &= 0x00FFFF;  /* clear reserved field */
 168                 ackno = (ackno << 32) + EXTRACT_32BITS(&ack_low);
 169         }
 170
 171         return ackno;
 172 }
 173
 174 static inline unsigned int dccp_basic_hdr_len(const struct dccp_hdr *dh)
 175 {
 176         return sizeof(*dh) + (DCCPH_X(dh) ? sizeof(struct dccp_hdr_ext) : 0);
 177 }
 178
 179 static inline unsigned int dccp_packet_hdr_len(const u_int8_t type)
 180 {
 181         if (type == DCCP_PKT_DATA)
 182                 return 0;
 183         if (type == DCCP_PKT_DATAACK    ||
 184             type == DCCP_PKT_ACK        ||
 185             type == DCCP_PKT_SYNC       ||
 186             type == DCCP_PKT_SYNCACK    ||
 187             type == DCCP_PKT_CLOSE      ||
 188             type == DCCP_PKT_CLOSEREQ)
 189                 return sizeof(struct dccp_hdr_ack_bits);
 190         if (type == DCCP_PKT_REQUEST)
 191                 return sizeof(struct dccp_hdr_request);
 192         if (type == DCCP_PKT_RESPONSE)
 193                 return sizeof(struct dccp_hdr_response);
 194         return sizeof(struct dccp_hdr_reset);
 195 }
 196
 197 static int dccp_print_option(const u_char *option);
 198
 199 /**
 200  * dccp_print - show dccp packet
 201  * @bp - beginning of dccp packet
 202  * @data2 - beginning of enclosing
 203  * @len - lenght of ip packet
 204  */
 205 void dccp_print(const u_char *bp, const u_char *data2, u_int len)
 206 {
 207         const struct dccp_hdr *dh;
 208         const struct ip *ip;
 209 #ifdef INET6
 210         const struct ip6_hdr *ip6;
 211 #endif
 212         const u_char *cp;
 213         u_short sport, dport;
 214         u_int hlen;
 215         u_int extlen = 0;
 216
 217         dh = (const struct dccp_hdr *)bp;
 218
 219         ip = (struct ip *)data2;
 220 #ifdef INET6
 221         if (IP_V(ip) == 6)
 222                 ip6 = (const struct ip6_hdr *)data2;
 223         else
 224                 ip6 = NULL;
 225 #endif /*INET6*/
 226         cp = (const u_char *)(dh + 1);
 227         if (cp > snapend) {
 228                 printf("[Invalid packet|dccp]");
 229                 return;
 230         }
 231
 232         if (len < sizeof(struct dccp_hdr)) {
 233                 printf("truncated-dccp - %ld bytes missing!",
 234                              (long)len - sizeof(struct dccp_hdr));
 235                 return;
 236         }
 237
 238         sport = EXTRACT_16BITS(&dh->dccph_sport);
 239         dport = EXTRACT_16BITS(&dh->dccph_dport);
 240         hlen = dh->dccph_doff * 4;
 241
 242 #ifdef INET6
 243         if (ip6) {
 244                 (void)printf("%s.%d > %s.%d: ",
 245                              ip6addr_string(&ip6->ip6_src), sport,
 246                              ip6addr_string(&ip6->ip6_dst), dport);
 247         } else
 248 #endif /*INET6*/
 249         {
 250                 (void)printf("%s.%d > %s.%d: ",
 251                              ipaddr_string(&ip->ip_src), sport,
 252                              ipaddr_string(&ip->ip_dst), dport);
 253         }
 254         fflush(stdout);
 255
 256         if (qflag) {
 257                 (void)printf(" %d", len - hlen);
 258                 if (hlen > len) {
 259                         (void)printf("dccp [bad hdr length %u - too long, > %u]",
 260                             hlen, len);
 261                 }
 262                 return;
 263         }
 264
 265         /* other variables in generic header */
 266         if (vflag) {
 267                 (void)printf("CCVal %d, CsCov %d, ", DCCPH_CCVAL(dh), DCCPH_CSCOV(dh));
 268         }
 269
 270         /* checksum calculation */
 271 #ifdef INET6
 272         if (ip6) {
 273                 if (ip6->ip6_plen && vflag) {
 274                         u_int16_t sum, dccp_sum;
 275
 276                         sum = dccp6_cksum(ip6, dh, len);
 277                         dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);
 278                         printf("cksum 0x%04x", dccp_sum);
 279                         if (sum != 0) {
 280                                 (void)printf(" (incorrect (-> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
 281                         } else
 282                                 (void)printf(" (correct), ");
 283                 }
 284         } else
 285 #endif /* INET6 */
 286         if (vflag)
 287         {
 288                 u_int16_t sum, dccp_sum;
 289
 290                 sum = dccp_cksum(ip, dh, len);
 291                 dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);
 292                 printf("cksum 0x%04x", dccp_sum);
 293                 if (sum != 0) {
 294                         (void)printf(" (incorrect (-> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
 295                 } else
 296                         (void)printf(" (correct), ");
 297         }
 298
 299         switch (DCCPH_TYPE(dh)) {
 300         case DCCP_PKT_REQUEST: {
 301                 struct dccp_hdr_request *dhr =
 302                         (struct dccp_hdr_request *)(bp + dccp_basic_hdr_len(dh));
 303                 TCHECK(*dhr);
 304                 (void)printf("request (service=%d) ", dhr->dccph_req_service);
 305                 extlen += 4;
 306                 break;
 307         }
 308         case DCCP_PKT_RESPONSE: {
 309                 struct dccp_hdr_response *dhr =
 310                         (struct dccp_hdr_response *)(bp + dccp_basic_hdr_len(dh));
 311                 TCHECK(*dhr);
 312                 (void)printf("response (service=%d, ack=%" PRIu64 ") ",
 313                              dhr->dccph_resp_service,
 314                              dccp_ack_no(dh,&(dhr->dccph_resp_ack)));
 315                 extlen += 12;
 316                 break;
 317         }
 318         case DCCP_PKT_DATA:
 319                 (void)printf("data ");
 320                 break;
 321         case DCCP_PKT_ACK: {
 322                 struct dccp_hdr_ack_bits *dha =
 323                         (struct dccp_hdr_ack_bits *)(bp + dccp_basic_hdr_len(dh));
 324                 TCHECK(*dha);
 325                 (void)printf("ack (ack=%" PRIu64 ") ",
 326                              dccp_ack_no(dh,dha));
 327                 extlen += 8;
 328                 break;
 329         }
 330         case DCCP_PKT_DATAACK: {
 331                 struct dccp_hdr_ack_bits *dha =
 332                         (struct dccp_hdr_ack_bits *)(bp + dccp_basic_hdr_len(dh));
 333                 TCHECK(*dha);
 334                 (void)printf("dataack (ack=%" PRIu64 ") ",
 335                              dccp_ack_no(dh,dha));
 336                 extlen += 8;
 337                 break;
 338         }
 339         case DCCP_PKT_CLOSEREQ:
 340                 (void)printf("closereq ");
 341                 extlen += 8;
 342                 break;
 343         case DCCP_PKT_CLOSE:
 344                 (void)printf("close ");
 345                 extlen += 8;
 346                 break;
 347         case DCCP_PKT_RESET: {
 348                 struct dccp_hdr_reset *dhr =
 349                         (struct dccp_hdr_reset *)(bp + dccp_basic_hdr_len(dh));
 350                 TCHECK(*dhr);
 351                 (void)printf("reset (code=%s) ",
 352                              dccp_reset_code(dhr->dccph_reset_code));
 353                 extlen += 12;
 354                 break;
 355         }
 356         case DCCP_PKT_SYNC:
 357                 (void)printf("sync ");
 358                 extlen += 8;
 359                 break;
 360         case DCCP_PKT_SYNCACK:
 361                 (void)printf("syncack ");
 362                 extlen += 8;
 363                 break;
 364         default:
 365                 (void)printf("invalid ");
 366                 break;
 367         }
 368
 369         if (vflag < 2)
 370                 return;
 371
 372         (void)printf("seq %" PRIu64, dccp_seqno(dh));
 373
 374         /* process options */
 375         if (hlen > dccp_basic_hdr_len(dh) + extlen){
 376                 const u_char *cp;
 377                 u_int optlen;
 378                 cp = bp + dccp_basic_hdr_len(dh) + extlen;
 379                 printf(" <");
 380
 381                 hlen -= dccp_basic_hdr_len(dh) + extlen;
 382                 while(1){
 383                         TCHECK(*cp);
 384                         optlen = dccp_print_option(cp);
 385                         if (!optlen) goto trunc2;
 386                         if (hlen <= optlen) break;
 387                         hlen -= optlen;
 388                         cp += optlen;
 389                         printf(", ");
 390                 }
 391                 printf(">");
 392         }
 393         return;
 394 trunc:
 395         printf("[|dccp]");
 396 trunc2:
 397         return;
 398 }
 399
 400 static int dccp_print_option(const u_char *option)
 401 {
 402         u_int8_t optlen, i;
 403         u_int32_t *ts;
 404         u_int16_t *var16;
 405         u_int32_t *var32;
 406
 407         TCHECK(*option);
 408
 409         if (*option >= 32) {
 410                 TCHECK(*(option+1));
 411                 optlen = *(option +1);
 412                 if (optlen < 2) {
 413                         printf("Option %d optlen too short",*option);
 414                         return 1;
 415                 }
 416         } else optlen = 1;
 417
 418         TCHECK2(*option,optlen);
 419
 420         switch (*option){
 421         case 0:
 422                 printf("nop");
 423                 break;
 424         case 1:
 425                 printf("mandatory");
 426                 break;
 427         case 2:
 428                 printf("slowreceiver");
 429                 break;
 430         case 32:
 431                 printf("change_l");
 432                 if (*(option +2) < 10){
 433                         printf(" %s", dccp_feature_nums[*(option +2)]);
 434                         for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
 435                 }
 436                 break;
 437         case 33:
 438                 printf("confirm_l");
 439                 if (*(option +2) < 10){
 440                         printf(" %s", dccp_feature_nums[*(option +2)]);
 441                         for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
 442                 }
 443                 break;
 444         case 34:
 445                 printf("change_r");
 446                 if (*(option +2) < 10){
 447                         printf(" %s", dccp_feature_nums[*(option +2)]);
 448                         for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
 449                 }
 450                 break;
 451         case 35:
 452                 printf("confirm_r");
 453                 if (*(option +2) < 10){
 454                         printf(" %s", dccp_feature_nums[*(option +2)]);
 455                         for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
 456                 }
 457                 break;
 458         case 36:
 459                 printf("initcookie 0x");
 460                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 461                 break;
 462         case 37:
 463                 printf("ndp_count");
 464                 for (i = 0; i < optlen -2; i ++) printf(" %d", *(option +2 + i));
 465                 break;
 466         case 38:
 467                 printf("ack_vector0 0x");
 468                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 469                 break;
 470         case 39:
 471                 printf("ack_vector1 0x");
 472                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 473                 break;
 474         case 40:
 475                 printf("data_dropped 0x");
 476                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 477                 break;
 478         case 41:
 479                 ts = (u_int32_t *)(option + 2);
 480                 printf("timestamp %u", (u_int32_t)ntohl(*ts));
 481                 break;
 482         case 42:
 483                 ts = (u_int32_t *)(option + 2);
 484                 printf("timestamp_echo %u", (u_int32_t)ntohl(*ts));
 485                 break;
 486         case 43:
 487                 printf("elapsed_time ");
 488                 if (optlen == 6){
 489                         ts = (u_int32_t *)(option + 2);
 490                         printf("%u", (u_int32_t)ntohl(*ts));
 491                 } else {
 492                         var16 = (u_int16_t *)(option + 2);
 493                         printf("%u", ntohs(*var16));
 494                 }
 495                 break;
 496         case 44:
 497                 printf("data_checksum ");
 498                 for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
 499                 break;
 500         default :
 501                 if (*option >= 128) {
 502                         printf("CCID option %d",*option);
 503                         switch (optlen) {
 504                                 case 4:
 505                                         var16 = (u_int16_t *)(option + 2);
 506                                         printf(" %u",ntohs(*var16));
 507                                         break;
 508                                 case 6:
 509                                         var32 = (u_int32_t *)(option + 2);
 510                                         printf(" %u",(u_int32_t)ntohl(*var32));
 511                                         break;
 512                                 default:
 513                                         break;
 514                         }
 515                         break;
 516                 }
 517
 518                 printf("unknown_opt %d", *option);
 519                 break;
 520         }
 521
 522         return optlen;
 523 trunc:
 524         printf("[|dccp]");
 525         return 0;
 526 }