1 /* NetBSD: print-tcp.c,v 1.9 2007/07/26 18:15:12 plunky Exp */ 2 3 /* 4 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Copyright (c) 1999-2004 The tcpdump.org project 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that: (1) source code distributions 11 * retain the above copyright notice and this paragraph in its entirety, (2) 12 * distributions including binary code include the above copyright notice and 13 * this paragraph in its entirety in the documentation or other materials 14 * provided with the distribution, and (3) all advertising materials mentioning 15 * features or use of this software display the following acknowledgement: 16 * ``This product includes software developed by the University of California, 17 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 18 * the University nor the names of its contributors may be used to endorse 19 * or promote products derived from this software without specific prior 20 * written permission. 21 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 22 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 23 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 24 */ 25 26 /* \summary: TCP printer */ 27 28 #include <sys/cdefs.h> 29 #ifndef lint 30 __RCSID("$NetBSD: print-tcp.c,v 1.11 2023/08/17 20:19:40 christos Exp $"); 31 #endif 32 33 #ifdef HAVE_CONFIG_H 34 #include <config.h> 35 #endif 36 37 #include "netdissect-stdinc.h" 38 39 #include <stdlib.h> 40 #include <string.h> 41 42 #include "netdissect.h" 43 #include "addrtoname.h" 44 #include "extract.h" 45 46 #include "diag-control.h" 47 48 #include "tcp.h" 49 50 #include "ip.h" 51 #include "ip6.h" 52 #include "ipproto.h" 53 #include "rpc_auth.h" 54 #include "rpc_msg.h" 55 56 #ifdef HAVE_LIBCRYPTO 57 #include <openssl/md5.h> 58 #include "signature.h" 59 60 static int tcp_verify_signature(netdissect_options *ndo, 61 const struct ip *ip, const struct tcphdr *tp, 62 const u_char *data, u_int length, const u_char *rcvsig); 63 #endif 64 65 static void print_tcp_rst_data(netdissect_options *, const u_char *sp, u_int length); 66 static void print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp, 67 u_int datalen, int exp); 68 69 #define MAX_RST_DATA_LEN 30 70 71 72 struct tha { 73 nd_ipv4 src; 74 nd_ipv4 dst; 75 u_int port; 76 }; 77 78 struct tcp_seq_hash { 79 struct tcp_seq_hash *nxt; 80 struct tha addr; 81 uint32_t seq; 82 uint32_t ack; 83 }; 84 85 struct tha6 { 86 nd_ipv6 src; 87 nd_ipv6 dst; 88 u_int port; 89 }; 90 91 struct tcp_seq_hash6 { 92 struct tcp_seq_hash6 *nxt; 93 struct tha6 addr; 94 uint32_t seq; 95 uint32_t ack; 96 }; 97 98 #define TSEQ_HASHSIZE 919 99 100 /* These tcp options do not have the size octet */ 101 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP) 102 103 static struct tcp_seq_hash tcp_seq_hash4[TSEQ_HASHSIZE]; 104 static struct tcp_seq_hash6 tcp_seq_hash6[TSEQ_HASHSIZE]; 105 106 static const struct tok tcp_flag_values[] = { 107 { TH_FIN, "F" }, 108 { TH_SYN, "S" }, 109 { TH_RST, "R" }, 110 { TH_PUSH, "P" }, 111 { TH_ACK, "." }, 112 { TH_URG, "U" }, 113 { TH_ECNECHO, "E" }, 114 { TH_CWR, "W" }, 115 { 0, NULL } 116 }; 117 118 static const struct tok tcp_option_values[] = { 119 { TCPOPT_EOL, "eol" }, 120 { TCPOPT_NOP, "nop" }, 121 { TCPOPT_MAXSEG, "mss" }, 122 { TCPOPT_WSCALE, "wscale" }, 123 { TCPOPT_SACKOK, "sackOK" }, 124 { TCPOPT_SACK, "sack" }, 125 { TCPOPT_ECHO, "echo" }, 126 { TCPOPT_ECHOREPLY, "echoreply" }, 127 { TCPOPT_TIMESTAMP, "TS" }, 128 { TCPOPT_CC, "cc" }, 129 { TCPOPT_CCNEW, "ccnew" }, 130 { TCPOPT_CCECHO, "" }, 131 { TCPOPT_SIGNATURE, "md5" }, 132 { TCPOPT_SCPS, "scps" }, 133 { TCPOPT_UTO, "uto" }, 134 { TCPOPT_TCPAO, "tcp-ao" }, 135 { TCPOPT_MPTCP, "mptcp" }, 136 { TCPOPT_FASTOPEN, "tfo" }, 137 { TCPOPT_EXPERIMENT2, "exp" }, 138 { 0, NULL } 139 }; 140 141 static uint16_t 142 tcp_cksum(netdissect_options *ndo, 143 const struct ip *ip, 144 const struct tcphdr *tp, 145 u_int len) 146 { 147 return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len, 148 IPPROTO_TCP); 149 } 150 151 static uint16_t 152 tcp6_cksum(netdissect_options *ndo, 153 const struct ip6_hdr *ip6, 154 const struct tcphdr *tp, 155 u_int len) 156 { 157 return nextproto6_cksum(ndo, ip6, (const uint8_t *)tp, len, len, 158 IPPROTO_TCP); 159 } 160 161 UNALIGNED_OK 162 void 163 tcp_print(netdissect_options *ndo, 164 const u_char *bp, u_int length, 165 const u_char *bp2, int fragmented) 166 { 167 const struct tcphdr *tp; 168 const struct ip *ip; 169 u_char flags; 170 u_int hlen; 171 char ch; 172 uint16_t sport, dport, win, urp; 173 uint32_t seq, ack, thseq, thack; 174 u_int utoval; 175 uint16_t magic; 176 int rev; 177 const struct ip6_hdr *ip6; 178 u_int header_len; /* Header length in bytes */ 179 180 ndo->ndo_protocol = "tcp"; 181 tp = (const struct tcphdr *)bp; 182 ip = (const struct ip *)bp2; 183 if (IP_V(ip) == 6) 184 ip6 = (const struct ip6_hdr *)bp2; 185 else 186 ip6 = NULL; 187 ch = '\0'; 188 if (!ND_TTEST_2(tp->th_dport)) { 189 if (ip6) { 190 ND_PRINT("%s > %s:", 191 GET_IP6ADDR_STRING(ip6->ip6_src), 192 GET_IP6ADDR_STRING(ip6->ip6_dst)); 193 } else { 194 ND_PRINT("%s > %s:", 195 GET_IPADDR_STRING(ip->ip_src), 196 GET_IPADDR_STRING(ip->ip_dst)); 197 } 198 nd_print_trunc(ndo); 199 return; 200 } 201 202 sport = GET_BE_U_2(tp->th_sport); 203 dport = GET_BE_U_2(tp->th_dport); 204 205 if (ip6) { 206 if (GET_U_1(ip6->ip6_nxt) == IPPROTO_TCP) { 207 ND_PRINT("%s.%s > %s.%s: ", 208 GET_IP6ADDR_STRING(ip6->ip6_src), 209 tcpport_string(ndo, sport), 210 GET_IP6ADDR_STRING(ip6->ip6_dst), 211 tcpport_string(ndo, dport)); 212 } else { 213 ND_PRINT("%s > %s: ", 214 tcpport_string(ndo, sport), tcpport_string(ndo, dport)); 215 } 216 } else { 217 if (GET_U_1(ip->ip_p) == IPPROTO_TCP) { 218 ND_PRINT("%s.%s > %s.%s: ", 219 GET_IPADDR_STRING(ip->ip_src), 220 tcpport_string(ndo, sport), 221 GET_IPADDR_STRING(ip->ip_dst), 222 tcpport_string(ndo, dport)); 223 } else { 224 ND_PRINT("%s > %s: ", 225 tcpport_string(ndo, sport), tcpport_string(ndo, dport)); 226 } 227 } 228 229 ND_TCHECK_SIZE(tp); 230 231 hlen = TH_OFF(tp) * 4; 232 233 if (hlen < sizeof(*tp)) { 234 ND_PRINT(" tcp %u [bad hdr length %u - too short, < %zu]", 235 length - hlen, hlen, sizeof(*tp)); 236 return; 237 } 238 239 seq = GET_BE_U_4(tp->th_seq); 240 ack = GET_BE_U_4(tp->th_ack); 241 win = GET_BE_U_2(tp->th_win); 242 urp = GET_BE_U_2(tp->th_urp); 243 244 if (ndo->ndo_qflag) { 245 ND_PRINT("tcp %u", length - hlen); 246 if (hlen > length) { 247 ND_PRINT(" [bad hdr length %u - too long, > %u]", 248 hlen, length); 249 } 250 return; 251 } 252 253 flags = GET_U_1(tp->th_flags); 254 ND_PRINT("Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags)); 255 256 if (!ndo->ndo_Sflag && (flags & TH_ACK)) { 257 /* 258 * Find (or record) the initial sequence numbers for 259 * this conversation. (we pick an arbitrary 260 * collating order so there's only one entry for 261 * both directions). 262 */ 263 rev = 0; 264 if (ip6) { 265 struct tcp_seq_hash6 *th; 266 struct tcp_seq_hash6 *tcp_seq_hash; 267 const void *src, *dst; 268 struct tha6 tha; 269 270 tcp_seq_hash = tcp_seq_hash6; 271 src = (const void *)ip6->ip6_src; 272 dst = (const void *)ip6->ip6_dst; 273 if (sport > dport) 274 rev = 1; 275 else if (sport == dport) { 276 if (UNALIGNED_MEMCMP(src, dst, sizeof(ip6->ip6_dst)) > 0) 277 rev = 1; 278 } 279 if (rev) { 280 UNALIGNED_MEMCPY(&tha.src, dst, sizeof(ip6->ip6_dst)); 281 UNALIGNED_MEMCPY(&tha.dst, src, sizeof(ip6->ip6_src)); 282 tha.port = ((u_int)dport) << 16 | sport; 283 } else { 284 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof(ip6->ip6_dst)); 285 UNALIGNED_MEMCPY(&tha.src, src, sizeof(ip6->ip6_src)); 286 tha.port = ((u_int)sport) << 16 | dport; 287 } 288 289 for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE]; 290 th->nxt; th = th->nxt) 291 if (memcmp((char *)&tha, (char *)&th->addr, 292 sizeof(th->addr)) == 0) 293 break; 294 295 if (!th->nxt || (flags & TH_SYN)) { 296 /* didn't find it or new conversation */ 297 /* calloc() return used by the 'tcp_seq_hash6' 298 hash table: do not free() */ 299 if (th->nxt == NULL) { 300 th->nxt = (struct tcp_seq_hash6 *) 301 calloc(1, sizeof(*th)); 302 if (th->nxt == NULL) 303 (*ndo->ndo_error)(ndo, 304 S_ERR_ND_MEM_ALLOC, 305 "%s: calloc", __func__); 306 } 307 th->addr = tha; 308 if (rev) 309 th->ack = seq, th->seq = ack - 1; 310 else 311 th->seq = seq, th->ack = ack - 1; 312 } else { 313 if (rev) 314 seq -= th->ack, ack -= th->seq; 315 else 316 seq -= th->seq, ack -= th->ack; 317 } 318 319 thseq = th->seq; 320 thack = th->ack; 321 } else { 322 struct tcp_seq_hash *th; 323 struct tcp_seq_hash *tcp_seq_hash; 324 struct tha tha; 325 326 tcp_seq_hash = tcp_seq_hash4; 327 if (sport > dport) 328 rev = 1; 329 else if (sport == dport) { 330 if (UNALIGNED_MEMCMP(ip->ip_src, ip->ip_dst, sizeof(ip->ip_dst)) > 0) 331 rev = 1; 332 } 333 if (rev) { 334 UNALIGNED_MEMCPY(&tha.src, ip->ip_dst, 335 sizeof(ip->ip_dst)); 336 UNALIGNED_MEMCPY(&tha.dst, ip->ip_src, 337 sizeof(ip->ip_src)); 338 tha.port = ((u_int)dport) << 16 | sport; 339 } else { 340 UNALIGNED_MEMCPY(&tha.dst, ip->ip_dst, 341 sizeof(ip->ip_dst)); 342 UNALIGNED_MEMCPY(&tha.src, ip->ip_src, 343 sizeof(ip->ip_src)); 344 tha.port = ((u_int)sport) << 16 | dport; 345 } 346 347 for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE]; 348 th->nxt; th = th->nxt) 349 if (memcmp((char *)&tha, (char *)&th->addr, 350 sizeof(th->addr)) == 0) 351 break; 352 353 if (!th->nxt || (flags & TH_SYN)) { 354 /* didn't find it or new conversation */ 355 /* calloc() return used by the 'tcp_seq_hash4' 356 hash table: do not free() */ 357 if (th->nxt == NULL) { 358 th->nxt = (struct tcp_seq_hash *) 359 calloc(1, sizeof(*th)); 360 if (th->nxt == NULL) 361 (*ndo->ndo_error)(ndo, 362 S_ERR_ND_MEM_ALLOC, 363 "%s: calloc", __func__); 364 } 365 th->addr = tha; 366 if (rev) 367 th->ack = seq, th->seq = ack - 1; 368 else 369 th->seq = seq, th->ack = ack - 1; 370 } else { 371 if (rev) 372 seq -= th->ack, ack -= th->seq; 373 else 374 seq -= th->seq, ack -= th->ack; 375 } 376 377 thseq = th->seq; 378 thack = th->ack; 379 } 380 } else { 381 /*fool gcc*/ 382 thseq = thack = rev = 0; 383 } 384 if (hlen > length) { 385 ND_PRINT(" [bad hdr length %u - too long, > %u]", 386 hlen, length); 387 return; 388 } 389 390 if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) { 391 /* Check the checksum, if possible. */ 392 uint16_t sum, tcp_sum; 393 394 if (IP_V(ip) == 4) { 395 if (ND_TTEST_LEN(tp->th_sport, length)) { 396 sum = tcp_cksum(ndo, ip, tp, length); 397 tcp_sum = GET_BE_U_2(tp->th_sum); 398 399 ND_PRINT(", cksum 0x%04x", tcp_sum); 400 if (sum != 0) 401 ND_PRINT(" (incorrect -> 0x%04x)", 402 in_cksum_shouldbe(tcp_sum, sum)); 403 else 404 ND_PRINT(" (correct)"); 405 } 406 } else if (IP_V(ip) == 6) { 407 if (ND_TTEST_LEN(tp->th_sport, length)) { 408 sum = tcp6_cksum(ndo, ip6, tp, length); 409 tcp_sum = GET_BE_U_2(tp->th_sum); 410 411 ND_PRINT(", cksum 0x%04x", tcp_sum); 412 if (sum != 0) 413 ND_PRINT(" (incorrect -> 0x%04x)", 414 in_cksum_shouldbe(tcp_sum, sum)); 415 else 416 ND_PRINT(" (correct)"); 417 418 } 419 } 420 } 421 422 length -= hlen; 423 if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) { 424 ND_PRINT(", seq %u", seq); 425 426 if (length > 0) { 427 ND_PRINT(":%u", seq + length); 428 } 429 } 430 431 if (flags & TH_ACK) { 432 ND_PRINT(", ack %u", ack); 433 } 434 435 ND_PRINT(", win %u", win); 436 437 if (flags & TH_URG) 438 ND_PRINT(", urg %u", urp); 439 /* 440 * Handle any options. 441 */ 442 if (hlen > sizeof(*tp)) { 443 const u_char *cp; 444 u_int i, opt, datalen; 445 u_int len; 446 447 hlen -= sizeof(*tp); 448 cp = (const u_char *)tp + sizeof(*tp); 449 ND_PRINT(", options ["); 450 while (hlen > 0) { 451 if (ch != '\0') 452 ND_PRINT("%c", ch); 453 opt = GET_U_1(cp); 454 cp++; 455 if (ZEROLENOPT(opt)) 456 len = 1; 457 else { 458 len = GET_U_1(cp); 459 cp++; /* total including type, len */ 460 if (len < 2 || len > hlen) 461 goto bad; 462 --hlen; /* account for length byte */ 463 } 464 --hlen; /* account for type byte */ 465 datalen = 0; 466 467 /* Bail if "l" bytes of data are not left or were not captured */ 468 #define LENCHECK(l) { if ((l) > hlen) goto bad; ND_TCHECK_LEN(cp, l); } 469 470 471 ND_PRINT("%s", tok2str(tcp_option_values, "unknown-%u", opt)); 472 473 switch (opt) { 474 475 case TCPOPT_MAXSEG: 476 datalen = 2; 477 LENCHECK(datalen); 478 ND_PRINT(" %u", GET_BE_U_2(cp)); 479 break; 480 481 case TCPOPT_WSCALE: 482 datalen = 1; 483 LENCHECK(datalen); 484 ND_PRINT(" %u", GET_U_1(cp)); 485 break; 486 487 case TCPOPT_SACK: 488 datalen = len - 2; 489 if (datalen % 8 != 0) { 490 ND_PRINT(" invalid sack"); 491 } else { 492 uint32_t s, e; 493 494 ND_PRINT(" %u ", datalen / 8); 495 for (i = 0; i < datalen; i += 8) { 496 LENCHECK(i + 4); 497 s = GET_BE_U_4(cp + i); 498 LENCHECK(i + 8); 499 e = GET_BE_U_4(cp + i + 4); 500 if (rev) { 501 s -= thseq; 502 e -= thseq; 503 } else { 504 s -= thack; 505 e -= thack; 506 } 507 ND_PRINT("{%u:%u}", s, e); 508 } 509 } 510 break; 511 512 case TCPOPT_CC: 513 case TCPOPT_CCNEW: 514 case TCPOPT_CCECHO: 515 case TCPOPT_ECHO: 516 case TCPOPT_ECHOREPLY: 517 518 /* 519 * those options share their semantics. 520 * fall through 521 */ 522 datalen = 4; 523 LENCHECK(datalen); 524 ND_PRINT(" %u", GET_BE_U_4(cp)); 525 break; 526 527 case TCPOPT_TIMESTAMP: 528 datalen = 8; 529 LENCHECK(datalen); 530 ND_PRINT(" val %u ecr %u", 531 GET_BE_U_4(cp), 532 GET_BE_U_4(cp + 4)); 533 break; 534 535 case TCPOPT_SIGNATURE: 536 datalen = TCP_SIGLEN; 537 LENCHECK(datalen); 538 ND_PRINT(" "); 539 #ifdef HAVE_LIBCRYPTO 540 switch (tcp_verify_signature(ndo, ip, tp, 541 bp + TH_OFF(tp) * 4, length, cp)) { 542 543 case SIGNATURE_VALID: 544 ND_PRINT("valid"); 545 break; 546 547 case SIGNATURE_INVALID: 548 nd_print_invalid(ndo); 549 break; 550 551 case CANT_CHECK_SIGNATURE: 552 ND_PRINT("can't check - "); 553 for (i = 0; i < TCP_SIGLEN; ++i) 554 ND_PRINT("%02x", 555 GET_U_1(cp + i)); 556 break; 557 } 558 #else 559 for (i = 0; i < TCP_SIGLEN; ++i) 560 ND_PRINT("%02x", GET_U_1(cp + i)); 561 #endif 562 break; 563 564 case TCPOPT_SCPS: 565 datalen = 2; 566 LENCHECK(datalen); 567 ND_PRINT(" cap %02x id %u", GET_U_1(cp), 568 GET_U_1(cp + 1)); 569 break; 570 571 case TCPOPT_TCPAO: 572 datalen = len - 2; 573 /* RFC 5925 Section 2.2: 574 * "The Length value MUST be greater than or equal to 4." 575 * (This includes the Kind and Length fields already processed 576 * at this point.) 577 */ 578 if (datalen < 2) { 579 nd_print_invalid(ndo); 580 } else { 581 LENCHECK(1); 582 ND_PRINT(" keyid %u", GET_U_1(cp)); 583 LENCHECK(2); 584 ND_PRINT(" rnextkeyid %u", 585 GET_U_1(cp + 1)); 586 if (datalen > 2) { 587 ND_PRINT(" mac 0x"); 588 for (i = 2; i < datalen; i++) { 589 LENCHECK(i + 1); 590 ND_PRINT("%02x", 591 GET_U_1(cp + i)); 592 } 593 } 594 } 595 break; 596 597 case TCPOPT_EOL: 598 case TCPOPT_NOP: 599 case TCPOPT_SACKOK: 600 /* 601 * Nothing interesting. 602 * fall through 603 */ 604 break; 605 606 case TCPOPT_UTO: 607 datalen = 2; 608 LENCHECK(datalen); 609 utoval = GET_BE_U_2(cp); 610 ND_PRINT(" 0x%x", utoval); 611 if (utoval & 0x0001) 612 utoval = (utoval >> 1) * 60; 613 else 614 utoval >>= 1; 615 ND_PRINT(" %u", utoval); 616 break; 617 618 case TCPOPT_MPTCP: 619 { 620 const u_char *snapend_save; 621 int ret; 622 623 datalen = len - 2; 624 LENCHECK(datalen); 625 /* Update the snapend to the end of the option 626 * before calling mptcp_print(). Some options 627 * (MPTCP or others) may be present after a 628 * MPTCP option. This prevents that, in 629 * mptcp_print(), the remaining length < the 630 * remaining caplen. 631 */ 632 snapend_save = ndo->ndo_snapend; 633 ndo->ndo_snapend = ND_MIN(cp - 2 + len, 634 ndo->ndo_snapend); 635 ret = mptcp_print(ndo, cp - 2, len, flags); 636 ndo->ndo_snapend = snapend_save; 637 if (!ret) 638 goto bad; 639 break; 640 } 641 642 case TCPOPT_FASTOPEN: 643 datalen = len - 2; 644 LENCHECK(datalen); 645 ND_PRINT(" "); 646 print_tcp_fastopen_option(ndo, cp, datalen, FALSE); 647 break; 648 649 case TCPOPT_EXPERIMENT2: 650 datalen = len - 2; 651 LENCHECK(datalen); 652 if (datalen < 2) 653 goto bad; 654 /* RFC6994 */ 655 magic = GET_BE_U_2(cp); 656 ND_PRINT("-"); 657 658 switch(magic) { 659 660 case 0xf989: /* TCP Fast Open RFC 7413 */ 661 print_tcp_fastopen_option(ndo, cp + 2, datalen - 2, TRUE); 662 break; 663 664 default: 665 /* Unknown magic number */ 666 ND_PRINT("%04x", magic); 667 break; 668 } 669 break; 670 671 default: 672 datalen = len - 2; 673 if (datalen) 674 ND_PRINT(" 0x"); 675 for (i = 0; i < datalen; ++i) { 676 LENCHECK(i + 1); 677 ND_PRINT("%02x", GET_U_1(cp + i)); 678 } 679 break; 680 } 681 682 /* Account for data printed */ 683 cp += datalen; 684 hlen -= datalen; 685 686 /* Check specification against observed length */ 687 ++datalen; /* option octet */ 688 if (!ZEROLENOPT(opt)) 689 ++datalen; /* size octet */ 690 if (datalen != len) 691 ND_PRINT("[len %u]", len); 692 ch = ','; 693 if (opt == TCPOPT_EOL) 694 break; 695 } 696 ND_PRINT("]"); 697 } 698 699 /* 700 * Print length field before crawling down the stack. 701 */ 702 ND_PRINT(", length %u", length); 703 704 if (length == 0) 705 return; 706 707 /* 708 * Decode payload if necessary. 709 */ 710 header_len = TH_OFF(tp) * 4; 711 /* 712 * Do a bounds check before decoding the payload. 713 * At least the header data is required. 714 */ 715 if (!ND_TTEST_LEN(bp, header_len)) { 716 ND_PRINT(" [remaining caplen(%u) < header length(%u)]", 717 ND_BYTES_AVAILABLE_AFTER(bp), header_len); 718 nd_trunc_longjmp(ndo); 719 } 720 bp += header_len; 721 if ((flags & TH_RST) && ndo->ndo_vflag) { 722 print_tcp_rst_data(ndo, bp, length); 723 return; 724 } 725 726 if (ndo->ndo_packettype) { 727 switch (ndo->ndo_packettype) { 728 case PT_ZMTP1: 729 zmtp1_print(ndo, bp, length); 730 break; 731 case PT_RESP: 732 resp_print(ndo, bp, length); 733 break; 734 case PT_DOMAIN: 735 /* over_tcp: TRUE, is_mdns: FALSE */ 736 domain_print(ndo, bp, length, TRUE, FALSE); 737 break; 738 } 739 return; 740 } 741 742 if (IS_SRC_OR_DST_PORT(TELNET_PORT)) { 743 telnet_print(ndo, bp, length); 744 } else if (IS_SRC_OR_DST_PORT(SMTP_PORT)) { 745 ND_PRINT(": "); 746 smtp_print(ndo, bp, length); 747 } else if (IS_SRC_OR_DST_PORT(WHOIS_PORT)) { 748 ND_PRINT(": "); 749 whois_print(ndo, bp, length); 750 } else if (IS_SRC_OR_DST_PORT(BGP_PORT)) 751 bgp_print(ndo, bp, length); 752 else if (IS_SRC_OR_DST_PORT(PPTP_PORT)) 753 pptp_print(ndo, bp); 754 else if (IS_SRC_OR_DST_PORT(REDIS_PORT)) 755 resp_print(ndo, bp, length); 756 else if (IS_SRC_OR_DST_PORT(SSH_PORT)) 757 ssh_print(ndo, bp, length); 758 #ifdef ENABLE_SMB 759 else if (IS_SRC_OR_DST_PORT(NETBIOS_SSN_PORT)) 760 nbt_tcp_print(ndo, bp, length); 761 else if (IS_SRC_OR_DST_PORT(SMB_PORT)) 762 smb_tcp_print(ndo, bp, length); 763 #endif 764 else if (IS_SRC_OR_DST_PORT(BEEP_PORT)) 765 beep_print(ndo, bp, length); 766 else if (IS_SRC_OR_DST_PORT(OPENFLOW_PORT_OLD) || IS_SRC_OR_DST_PORT(OPENFLOW_PORT_IANA)) 767 openflow_print(ndo, bp, length); 768 else if (IS_SRC_OR_DST_PORT(FTP_PORT)) { 769 ND_PRINT(": "); 770 ftp_print(ndo, bp, length); 771 } else if (IS_SRC_OR_DST_PORT(HTTP_PORT) || IS_SRC_OR_DST_PORT(HTTP_PORT_ALT)) { 772 ND_PRINT(": "); 773 http_print(ndo, bp, length); 774 } else if (IS_SRC_OR_DST_PORT(RTSP_PORT) || IS_SRC_OR_DST_PORT(RTSP_PORT_ALT)) { 775 ND_PRINT(": "); 776 rtsp_print(ndo, bp, length); 777 } else if (IS_SRC_OR_DST_PORT(NAMESERVER_PORT)) { 778 /* over_tcp: TRUE, is_mdns: FALSE */ 779 domain_print(ndo, bp, length, TRUE, FALSE); 780 } else if (IS_SRC_OR_DST_PORT(MSDP_PORT)) { 781 msdp_print(ndo, bp, length); 782 } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT)) { 783 rpki_rtr_print(ndo, bp, length); 784 } else if (IS_SRC_OR_DST_PORT(LDP_PORT)) { 785 ldp_print(ndo, bp, length); 786 } else if ((IS_SRC_OR_DST_PORT(NFS_PORT)) && 787 length >= 4 && ND_TTEST_4(bp)) { 788 /* 789 * If data present, header length valid, and NFS port used, 790 * assume NFS. 791 * Pass offset of data plus 4 bytes for RPC TCP msg length 792 * to NFS print routines. 793 */ 794 uint32_t fraglen; 795 const struct sunrpc_msg *rp; 796 enum sunrpc_msg_type direction; 797 798 fraglen = GET_BE_U_4(bp) & 0x7FFFFFFF; 799 if (fraglen > (length) - 4) 800 fraglen = (length) - 4; 801 rp = (const struct sunrpc_msg *)(bp + 4); 802 if (ND_TTEST_4(rp->rm_direction)) { 803 direction = (enum sunrpc_msg_type) GET_BE_U_4(rp->rm_direction); 804 if (dport == NFS_PORT && direction == SUNRPC_CALL) { 805 ND_PRINT(": NFS request xid %u ", 806 GET_BE_U_4(rp->rm_xid)); 807 nfsreq_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip); 808 return; 809 } 810 if (sport == NFS_PORT && direction == SUNRPC_REPLY) { 811 ND_PRINT(": NFS reply xid %u ", 812 GET_BE_U_4(rp->rm_xid)); 813 nfsreply_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip); 814 return; 815 } 816 } 817 } 818 819 return; 820 bad: 821 ND_PRINT("[bad opt]"); 822 if (ch != '\0') 823 ND_PRINT("]"); 824 return; 825 trunc: 826 nd_print_trunc(ndo); 827 if (ch != '\0') 828 ND_PRINT(">"); 829 } 830 831 /* 832 * RFC1122 says the following on data in RST segments: 833 * 834 * 4.2.2.12 RST Segment: RFC-793 Section 3.4 835 * 836 * A TCP SHOULD allow a received RST segment to include data. 837 * 838 * DISCUSSION 839 * It has been suggested that a RST segment could contain 840 * ASCII text that encoded and explained the cause of the 841 * RST. No standard has yet been established for such 842 * data. 843 * 844 */ 845 846 static void 847 print_tcp_rst_data(netdissect_options *ndo, 848 const u_char *sp, u_int length) 849 { 850 u_char c; 851 852 ND_PRINT(ND_TTEST_LEN(sp, length) ? " [RST" : " [!RST"); 853 if (length > MAX_RST_DATA_LEN) { 854 length = MAX_RST_DATA_LEN; /* can use -X for longer */ 855 ND_PRINT("+"); /* indicate we truncate */ 856 } 857 ND_PRINT(" "); 858 while (length && sp < ndo->ndo_snapend) { 859 c = GET_U_1(sp); 860 sp++; 861 fn_print_char(ndo, c); 862 length--; 863 } 864 ND_PRINT("]"); 865 } 866 867 static void 868 print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp, 869 u_int datalen, int exp) 870 { 871 u_int i; 872 873 if (exp) 874 ND_PRINT("tfo"); 875 876 if (datalen == 0) { 877 /* Fast Open Cookie Request */ 878 ND_PRINT(" cookiereq"); 879 } else { 880 /* Fast Open Cookie */ 881 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) { 882 nd_print_invalid(ndo); 883 } else { 884 ND_PRINT(" cookie "); 885 for (i = 0; i < datalen; ++i) 886 ND_PRINT("%02x", GET_U_1(cp + i)); 887 } 888 } 889 } 890 891 #ifdef HAVE_LIBCRYPTO 892 DIAG_OFF_DEPRECATION 893 static int 894 tcp_verify_signature(netdissect_options *ndo, 895 const struct ip *ip, const struct tcphdr *tp, 896 const u_char *data, u_int length, const u_char *rcvsig) 897 { 898 struct tcphdr tp1; 899 u_char sig[TCP_SIGLEN]; 900 char zero_proto = 0; 901 MD5_CTX ctx; 902 uint16_t savecsum, tlen; 903 const struct ip6_hdr *ip6; 904 uint32_t len32; 905 uint8_t nxt; 906 907 if (data + length > ndo->ndo_snapend) { 908 ND_PRINT("snaplen too short, "); 909 return (CANT_CHECK_SIGNATURE); 910 } 911 912 tp1 = *tp; 913 914 if (ndo->ndo_sigsecret == NULL) { 915 ND_PRINT("shared secret not supplied with -M, "); 916 return (CANT_CHECK_SIGNATURE); 917 } 918 919 MD5_Init(&ctx); 920 /* 921 * Step 1: Update MD5 hash with IP pseudo-header. 922 */ 923 if (IP_V(ip) == 4) { 924 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src)); 925 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst)); 926 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto)); 927 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p)); 928 tlen = GET_BE_U_2(ip->ip_len) - IP_HL(ip) * 4; 929 tlen = htons(tlen); 930 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen)); 931 } else if (IP_V(ip) == 6) { 932 ip6 = (const struct ip6_hdr *)ip; 933 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src)); 934 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst)); 935 len32 = htonl(GET_BE_U_2(ip6->ip6_plen)); 936 MD5_Update(&ctx, (const char *)&len32, sizeof(len32)); 937 nxt = 0; 938 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt)); 939 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt)); 940 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt)); 941 nxt = IPPROTO_TCP; 942 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt)); 943 } else { 944 ND_PRINT("IP version not 4 or 6, "); 945 return (CANT_CHECK_SIGNATURE); 946 } 947 948 /* 949 * Step 2: Update MD5 hash with TCP header, excluding options. 950 * The TCP checksum must be set to zero. 951 */ 952 memcpy(&savecsum, tp1.th_sum, sizeof(savecsum)); 953 memset(tp1.th_sum, 0, sizeof(tp1.th_sum)); 954 MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr)); 955 memcpy(tp1.th_sum, &savecsum, sizeof(tp1.th_sum)); 956 /* 957 * Step 3: Update MD5 hash with TCP segment data, if present. 958 */ 959 if (length > 0) 960 MD5_Update(&ctx, data, length); 961 /* 962 * Step 4: Update MD5 hash with shared secret. 963 */ 964 MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret)); 965 MD5_Final(sig, &ctx); 966 967 if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0) 968 return (SIGNATURE_VALID); 969 else 970 return (SIGNATURE_INVALID); 971 } 972 DIAG_ON_DEPRECATION 973 #endif /* HAVE_LIBCRYPTO */ 974