/* $NetBSD: print-tcp.c,v 1.9 2007/07/26 18:15:12 plunky Exp $ */ /* * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997 * The Regents of the University of California. All rights reserved. * * Copyright (c) 1999-2004 The tcpdump.org project * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that: (1) source code distributions * retain the above copyright notice and this paragraph in its entirety, (2) * distributions including binary code include the above copyright notice and * this paragraph in its entirety in the documentation or other materials * provided with the distribution, and (3) all advertising materials mentioning * features or use of this software display the following acknowledgement: * ``This product includes software developed by the University of California, * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of * the University nor the names of its contributors may be used to endorse * or promote products derived from this software without specific prior * written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ #ifndef lint static const char rcsid[] _U_ = "@(#) $Header: /tcpdump/master/tcpdump/print-tcp.c,v 1.135 2008-11-09 23:35:03 mcr Exp $ (LBL)"; #else __RCSID("$NetBSD: print-tcp.c,v 1.8 2007/07/24 11:53:48 drochner Exp $"); #endif #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include #include #include "interface.h" #include "addrtoname.h" #include "extract.h" #include "tcp.h" #include "ip.h" #ifdef INET6 #include "ip6.h" #endif #include "ipproto.h" #include "rpc_auth.h" #include "rpc_msg.h" #include "nameser.h" #ifdef HAVE_LIBCRYPTO #include #include static int tcp_verify_signature(const struct ip *ip, const struct tcphdr *tp, const u_char *data, int length, const u_char *rcvsig); #endif static void print_tcp_rst_data(register const u_char *sp, u_int length); #define MAX_RST_DATA_LEN 30 struct tha { #ifndef INET6 struct in_addr src; struct in_addr dst; #else struct in6_addr src; struct in6_addr dst; #endif /*INET6*/ u_int port; }; struct tcp_seq_hash { struct tcp_seq_hash *nxt; struct tha addr; tcp_seq seq; tcp_seq ack; }; #define TSEQ_HASHSIZE 919 /* These tcp optinos do not have the size octet */ #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP) static struct tcp_seq_hash tcp_seq_hash[TSEQ_HASHSIZE]; struct tok tcp_flag_values[] = { { TH_FIN, "F" }, { TH_SYN, "S" }, { TH_RST, "R" }, { TH_PUSH, "P" }, { TH_ACK, "." }, { TH_URG, "U" }, { TH_ECNECHO, "E" }, { TH_CWR, "W" }, { 0, NULL } }; struct tok tcp_option_values[] = { { TCPOPT_EOL, "eol" }, { TCPOPT_NOP, "nop" }, { TCPOPT_MAXSEG, "mss" }, { TCPOPT_WSCALE, "wscale" }, { TCPOPT_SACKOK, "sackOK" }, { TCPOPT_SACK, "sack" }, { TCPOPT_ECHO, "echo" }, { TCPOPT_ECHOREPLY, "echoreply" }, { TCPOPT_TIMESTAMP, "TS" }, { TCPOPT_CC, "cc" }, { TCPOPT_CCNEW, "ccnew" }, { TCPOPT_CCECHO, "" }, { TCPOPT_SIGNATURE, "md5" }, { TCPOPT_AUTH, "enhanced auth" }, { TCPOPT_UTO, "uto" }, { 0, NULL } }; static int tcp_cksum(register const struct ip *ip, register const struct tcphdr *tp, register u_int len) { return (nextproto4_cksum(ip, (const u_int8_t *)tp, len, IPPROTO_TCP)); } void tcp_print(register const u_char *bp, register u_int length, register const u_char *bp2, int fragmented) { register const struct tcphdr *tp; register const struct ip *ip; register u_char flags; register u_int hlen; register char ch; u_int16_t sport, dport, win, urp; u_int32_t seq, ack, thseq, thack; u_int utoval; int threv; #ifdef INET6 register const struct ip6_hdr *ip6; #endif tp = (struct tcphdr *)bp; ip = (struct ip *)bp2; #ifdef INET6 if (IP_V(ip) == 6) ip6 = (struct ip6_hdr *)bp2; else ip6 = NULL; #endif /*INET6*/ ch = '\0'; if (!TTEST(tp->th_dport)) { (void)printf("%s > %s: [|tcp]", ipaddr_string(&ip->ip_src), ipaddr_string(&ip->ip_dst)); return; } sport = EXTRACT_16BITS(&tp->th_sport); dport = EXTRACT_16BITS(&tp->th_dport); hlen = TH_OFF(tp) * 4; /* * If data present, header length valid, and NFS port used, * assume NFS. * Pass offset of data plus 4 bytes for RPC TCP msg length * to NFS print routines. */ if (!qflag && hlen >= sizeof(*tp) && hlen <= length && (length - hlen) >= 4) { u_char *fraglenp; u_int32_t fraglen; register struct sunrpc_msg *rp; enum sunrpc_msg_type direction; fraglenp = (u_char *)tp + hlen; if (TTEST2(*fraglenp, 4)) { fraglen = EXTRACT_32BITS(fraglenp) & 0x7FFFFFFF; if (fraglen > (length - hlen) - 4) fraglen = (length - hlen) - 4; rp = (struct sunrpc_msg *)(fraglenp + 4); if (TTEST(rp->rm_direction)) { direction = (enum sunrpc_msg_type)EXTRACT_32BITS(&rp->rm_direction); if (dport == NFS_PORT && direction == SUNRPC_CALL) { nfsreq_print((u_char *)rp, fraglen, (u_char *)ip); return; } if (sport == NFS_PORT && direction == SUNRPC_REPLY) { nfsreply_print((u_char *)rp, fraglen, (u_char *)ip); return; } } } } #ifdef INET6 if (ip6) { if (ip6->ip6_nxt == IPPROTO_TCP) { (void)printf("%s.%s > %s.%s: ", ip6addr_string(&ip6->ip6_src), tcpport_string(sport), ip6addr_string(&ip6->ip6_dst), tcpport_string(dport)); } else { (void)printf("%s > %s: ", tcpport_string(sport), tcpport_string(dport)); } } else #endif /*INET6*/ { if (ip->ip_p == IPPROTO_TCP) { (void)printf("%s.%s > %s.%s: ", ipaddr_string(&ip->ip_src), tcpport_string(sport), ipaddr_string(&ip->ip_dst), tcpport_string(dport)); } else { (void)printf("%s > %s: ", tcpport_string(sport), tcpport_string(dport)); } } if (hlen < sizeof(*tp)) { (void)printf(" tcp %d [bad hdr length %u - too short, < %lu]", length - hlen, hlen, (unsigned long)sizeof(*tp)); return; } TCHECK(*tp); seq = EXTRACT_32BITS(&tp->th_seq); ack = EXTRACT_32BITS(&tp->th_ack); win = EXTRACT_16BITS(&tp->th_win); urp = EXTRACT_16BITS(&tp->th_urp); if (qflag) { (void)printf("tcp %d", length - hlen); if (hlen > length) { (void)printf(" [bad hdr length %u - too long, > %u]", hlen, length); } return; } flags = tp->th_flags; printf("Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags)); if (!Sflag && (flags & TH_ACK)) { register struct tcp_seq_hash *th; const void *src, *dst; register int rev; struct tha tha; /* * Find (or record) the initial sequence numbers for * this conversation. (we pick an arbitrary * collating order so there's only one entry for * both directions). */ #ifdef INET6 rev = 0; if (ip6) { src = &ip6->ip6_src; dst = &ip6->ip6_dst; if (sport > dport) rev = 1; else if (sport == dport) { if (memcmp(src, dst, sizeof ip6->ip6_dst) > 0) rev = 1; } if (rev) { memcpy(&tha.src, dst, sizeof ip6->ip6_dst); memcpy(&tha.dst, src, sizeof ip6->ip6_src); tha.port = dport << 16 | sport; } else { memcpy(&tha.dst, dst, sizeof ip6->ip6_dst); memcpy(&tha.src, src, sizeof ip6->ip6_src); tha.port = sport << 16 | dport; } } else { /* * Zero out the tha structure; the src and dst * fields are big enough to hold an IPv6 * address, but we only have IPv4 addresses * and thus must clear out the remaining 124 * bits. * * XXX - should we just clear those bytes after * copying the IPv4 addresses, rather than * zeroing out the entire structure and then * overwriting some of the zeroes? * * XXX - this could fail if we see TCP packets * with an IPv6 address with the lower 124 bits * all zero and also see TCP packes with an * IPv4 address with the same 32 bits as the * upper 32 bits of the IPv6 address in question. * Can that happen? Is it likely enough to be * an issue? */ memset(&tha, 0, sizeof(tha)); src = &ip->ip_src; dst = &ip->ip_dst; if (sport > dport) rev = 1; else if (sport == dport) { if (memcmp(src, dst, sizeof ip->ip_dst) > 0) rev = 1; } if (rev) { memcpy(&tha.src, dst, sizeof ip->ip_dst); memcpy(&tha.dst, src, sizeof ip->ip_src); tha.port = dport << 16 | sport; } else { memcpy(&tha.dst, dst, sizeof ip->ip_dst); memcpy(&tha.src, src, sizeof ip->ip_src); tha.port = sport << 16 | dport; } } #else rev = 0; src = &ip->ip_src; dst = &ip->ip_dst; if (sport > dport) rev = 1; else if (sport == dport) { if (memcmp(src, dst, sizeof ip->ip_dst) > 0) rev = 1; } if (rev) { memcpy(&tha.src, dst, sizeof ip->ip_dst); memcpy(&tha.dst, src, sizeof ip->ip_src); tha.port = dport << 16 | sport; } else { memcpy(&tha.dst, dst, sizeof ip->ip_dst); memcpy(&tha.src, src, sizeof ip->ip_src); tha.port = sport << 16 | dport; } #endif threv = rev; for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE]; th->nxt; th = th->nxt) if (memcmp((char *)&tha, (char *)&th->addr, sizeof(th->addr)) == 0) break; if (!th->nxt || (flags & TH_SYN)) { /* didn't find it or new conversation */ if (th->nxt == NULL) { th->nxt = (struct tcp_seq_hash *) calloc(1, sizeof(*th)); if (th->nxt == NULL) error("tcp_print: calloc"); } th->addr = tha; if (rev) th->ack = seq, th->seq = ack - 1; else th->seq = seq, th->ack = ack - 1; } else { if (rev) seq -= th->ack, ack -= th->seq; else seq -= th->seq, ack -= th->ack; } thseq = th->seq; thack = th->ack; } else { /*fool gcc*/ thseq = thack = threv = 0; } if (hlen > length) { (void)printf(" [bad hdr length %u - too long, > %u]", hlen, length); return; } if (vflag && !Kflag && !fragmented) { /* Check the checksum, if possible. */ u_int16_t sum, tcp_sum; if (IP_V(ip) == 4) { if (TTEST2(tp->th_sport, length)) { sum = tcp_cksum(ip, tp, length); tcp_sum = EXTRACT_16BITS(&tp->th_sum); (void)printf(", cksum 0x%04x", tcp_sum); if (sum != 0) (void)printf(" (incorrect -> 0x%04x)", in_cksum_shouldbe(tcp_sum, sum)); else (void)printf(" (correct)"); } } #ifdef INET6 else if (IP_V(ip) == 6 && ip6->ip6_plen) { if (TTEST2(tp->th_sport, length)) { sum = nextproto6_cksum(ip6, (const u_int8_t *)tp, length, IPPROTO_TCP); tcp_sum = EXTRACT_16BITS(&tp->th_sum); (void)printf(", cksum 0x%04x", tcp_sum); if (sum != 0) (void)printf(" (incorrect -> 0x%04x)", in_cksum_shouldbe(tcp_sum, sum)); else (void)printf(" (correct)"); } } #endif } length -= hlen; if (vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) { (void)printf(", seq %u", seq); if (length > 0) { (void)printf(":%u", seq + length); } } if (flags & TH_ACK) { (void)printf(", ack %u", ack); } (void)printf(", win %d", win); if (flags & TH_URG) (void)printf(", urg %d", urp); /* * Handle any options. */ if (hlen > sizeof(*tp)) { register const u_char *cp; register u_int i, opt, datalen; register u_int len; hlen -= sizeof(*tp); cp = (const u_char *)tp + sizeof(*tp); printf(", options ["); while (hlen > 0) { if (ch != '\0') putchar(ch); TCHECK(*cp); opt = *cp++; if (ZEROLENOPT(opt)) len = 1; else { TCHECK(*cp); len = *cp++; /* total including type, len */ if (len < 2 || len > hlen) goto bad; --hlen; /* account for length byte */ } --hlen; /* account for type byte */ datalen = 0; /* Bail if "l" bytes of data are not left or were not captured */ #define LENCHECK(l) { if ((l) > hlen) goto bad; TCHECK2(*cp, l); } printf("%s", tok2str(tcp_option_values, "Unknown Option %u", opt)); switch (opt) { case TCPOPT_MAXSEG: datalen = 2; LENCHECK(datalen); (void)printf(" %u", EXTRACT_16BITS(cp)); break; case TCPOPT_WSCALE: datalen = 1; LENCHECK(datalen); (void)printf(" %u", *cp); break; case TCPOPT_SACK: datalen = len - 2; if (datalen % 8 != 0) { (void)printf("malformed sack"); } else { u_int32_t s, e; (void)printf(" %d ", datalen / 8); for (i = 0; i < datalen; i += 8) { LENCHECK(i + 4); s = EXTRACT_32BITS(cp + i); LENCHECK(i + 8); e = EXTRACT_32BITS(cp + i + 4); if (threv) { s -= thseq; e -= thseq; } else { s -= thack; e -= thack; } (void)printf("{%u:%u}", s, e); } } break; case TCPOPT_CC: case TCPOPT_CCNEW: case TCPOPT_CCECHO: case TCPOPT_ECHO: case TCPOPT_ECHOREPLY: /* * those options share their semantics. * fall through */ datalen = 4; LENCHECK(datalen); (void)printf(" %u", EXTRACT_32BITS(cp)); break; case TCPOPT_TIMESTAMP: datalen = 8; LENCHECK(datalen); (void)printf(" val %u ecr %u", EXTRACT_32BITS(cp), EXTRACT_32BITS(cp + 4)); break; case TCPOPT_SIGNATURE: datalen = TCP_SIGLEN; LENCHECK(datalen); #ifdef HAVE_LIBCRYPTO switch (tcp_verify_signature(ip, tp, bp + TH_OFF(tp) * 4, length, cp)) { case SIGNATURE_VALID: (void)printf("valid"); break; case SIGNATURE_INVALID: (void)printf("invalid"); break; case CANT_CHECK_SIGNATURE: (void)printf("can't check - "); for (i = 0; i < TCP_SIGLEN; ++i) (void)printf("%02x", cp[i]); break; } #else for (i = 0; i < TCP_SIGLEN; ++i) (void)printf("%02x", cp[i]); #endif break; case TCPOPT_AUTH: (void)printf("keyid %d", *cp++); datalen = len - 3; for (i = 0; i < datalen; ++i) { LENCHECK(i); (void)printf("%02x", cp[i]); } break; case TCPOPT_EOL: case TCPOPT_NOP: case TCPOPT_SACKOK: /* * Nothing interesting. * fall through */ break; case TCPOPT_UTO: datalen = 2; LENCHECK(datalen); utoval = EXTRACT_16BITS(cp); (void)printf("0x%x", utoval); if (utoval & 0x0001) utoval = (utoval >> 1) * 60; else utoval >>= 1; (void)printf(" %u", utoval); break; default: datalen = len - 2; for (i = 0; i < datalen; ++i) { LENCHECK(i); (void)printf("%02x", cp[i]); } break; } /* Account for data printed */ cp += datalen; hlen -= datalen; /* Check specification against observed length */ ++datalen; /* option octet */ if (!ZEROLENOPT(opt)) ++datalen; /* size octet */ if (datalen != len) (void)printf("[len %d]", len); ch = ','; if (opt == TCPOPT_EOL) break; } putchar(']'); } /* * Print length field before crawling down the stack. */ printf(", length %u", length); if (length <= 0) return; /* * Decode payload if necessary. */ bp += TH_OFF(tp) * 4; if ((flags & TH_RST) && vflag) { print_tcp_rst_data(bp, length); return; } if (sport == TELNET_PORT || dport == TELNET_PORT) { if (!qflag && vflag) telnet_print(bp, length); } else if (sport == BGP_PORT || dport == BGP_PORT) bgp_print(bp, length); else if (sport == PPTP_PORT || dport == PPTP_PORT) pptp_print(bp); #ifdef TCPDUMP_DO_SMB else if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT) nbt_tcp_print(bp, length); else if (sport == SMB_PORT || dport == SMB_PORT) smb_tcp_print(bp, length); #endif else if (sport == BEEP_PORT || dport == BEEP_PORT) beep_print(bp, length); else if (length > 2 && (sport == NAMESERVER_PORT || dport == NAMESERVER_PORT || sport == MULTICASTDNS_PORT || dport == MULTICASTDNS_PORT)) { /* * TCP DNS query has 2byte length at the head. * XXX packet could be unaligned, it can go strange */ ns_print(bp + 2, length - 2, 0); } else if (sport == MSDP_PORT || dport == MSDP_PORT) { msdp_print(bp, length); } else if (sport == RPKI_RTR_PORT || dport == RPKI_RTR_PORT) { rpki_rtr_print(bp, length); } else if (length > 0 && (sport == LDP_PORT || dport == LDP_PORT)) { ldp_print(bp, length); } return; bad: fputs("[bad opt]", stdout); if (ch != '\0') putchar('>'); return; trunc: fputs("[|tcp]", stdout); if (ch != '\0') putchar('>'); } /* * RFC1122 says the following on data in RST segments: * * 4.2.2.12 RST Segment: RFC-793 Section 3.4 * * A TCP SHOULD allow a received RST segment to include data. * * DISCUSSION * It has been suggested that a RST segment could contain * ASCII text that encoded and explained the cause of the * RST. No standard has yet been established for such * data. * */ static void print_tcp_rst_data(register const u_char *sp, u_int length) { int c; if (TTEST2(*sp, length)) printf(" [RST"); else printf(" [!RST"); if (length > MAX_RST_DATA_LEN) { length = MAX_RST_DATA_LEN; /* can use -X for longer */ putchar('+'); /* indicate we truncate */ } putchar(' '); while (length-- && sp <= snapend) { c = *sp++; safeputchar(c); } putchar(']'); } #ifdef HAVE_LIBCRYPTO static int tcp_verify_signature(const struct ip *ip, const struct tcphdr *tp, const u_char *data, int length, const u_char *rcvsig) { struct tcphdr tp1; u_char sig[TCP_SIGLEN]; char zero_proto = 0; MD5_CTX ctx; u_int16_t savecsum, tlen; #ifdef INET6 struct ip6_hdr *ip6; u_int32_t len32; u_int8_t nxt; #endif if (data + length > snapend) { printf("snaplen too short, "); return (CANT_CHECK_SIGNATURE); } tp1 = *tp; if (sigsecret == NULL) { printf("shared secret not supplied with -M, "); return (CANT_CHECK_SIGNATURE); } MD5_Init(&ctx); /* * Step 1: Update MD5 hash with IP pseudo-header. */ if (IP_V(ip) == 4) { MD5_Update(&ctx, (char *)&ip->ip_src, sizeof(ip->ip_src)); MD5_Update(&ctx, (char *)&ip->ip_dst, sizeof(ip->ip_dst)); MD5_Update(&ctx, (char *)&zero_proto, sizeof(zero_proto)); MD5_Update(&ctx, (char *)&ip->ip_p, sizeof(ip->ip_p)); tlen = EXTRACT_16BITS(&ip->ip_len) - IP_HL(ip) * 4; tlen = htons(tlen); MD5_Update(&ctx, (char *)&tlen, sizeof(tlen)); #ifdef INET6 } else if (IP_V(ip) == 6) { ip6 = (struct ip6_hdr *)ip; MD5_Update(&ctx, (char *)&ip6->ip6_src, sizeof(ip6->ip6_src)); MD5_Update(&ctx, (char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst)); len32 = htonl(EXTRACT_16BITS(&ip6->ip6_plen)); MD5_Update(&ctx, (char *)&len32, sizeof(len32)); nxt = 0; MD5_Update(&ctx, (char *)&nxt, sizeof(nxt)); MD5_Update(&ctx, (char *)&nxt, sizeof(nxt)); MD5_Update(&ctx, (char *)&nxt, sizeof(nxt)); nxt = IPPROTO_TCP; MD5_Update(&ctx, (char *)&nxt, sizeof(nxt)); #endif } else { #ifdef INET6 printf("IP version not 4 or 6, "); #else printf("IP version not 4, "); #endif return (CANT_CHECK_SIGNATURE); } /* * Step 2: Update MD5 hash with TCP header, excluding options. * The TCP checksum must be set to zero. */ savecsum = tp1.th_sum; tp1.th_sum = 0; MD5_Update(&ctx, (char *)&tp1, sizeof(struct tcphdr)); tp1.th_sum = savecsum; /* * Step 3: Update MD5 hash with TCP segment data, if present. */ if (length > 0) MD5_Update(&ctx, data, length); /* * Step 4: Update MD5 hash with shared secret. */ MD5_Update(&ctx, sigsecret, strlen(sigsecret)); MD5_Final(sig, &ctx); if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0) return (SIGNATURE_VALID); else return (SIGNATURE_INVALID); } #endif /* HAVE_LIBCRYPTO */ /* * Local Variables: * c-style: whitesmith * c-basic-offset: 8 * End: */