X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/3472526186b90037dbb016feab89f5ad33db6e75..39f09d68ce7ebe9e229c9bf5209bfc30a8f51064:/print-tcp.c diff --git a/print-tcp.c b/print-tcp.c index 2846b246..0c250a07 100644 --- a/print-tcp.c +++ b/print-tcp.c @@ -1,3 +1,5 @@ +/* $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. @@ -21,672 +23,815 @@ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ +/* \summary: TCP printer */ + #ifndef lint -static const char rcsid[] _U_ = - "@(#) $Header: /tcpdump/master/tcpdump/print-tcp.c,v 1.126 2006-11-02 08:56:16 hannes 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" +#include #endif -#include +#include "netdissect-stdinc.h" -#include #include #include -#include "interface.h" +#define ND_LONGJMP_FROM_TCHECK +#include "netdissect.h" #include "addrtoname.h" #include "extract.h" +#include "diag-control.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 "signature.h" -#define SIGNATURE_VALID 0 -#define SIGNATURE_INVALID 1 -#define CANT_CHECK_SIGNATURE 2 - -static int tcp_verify_signature(const struct ip *ip, const struct tcphdr *tp, - const u_char *data, int length, const u_char *rcvsig); +static int tcp_verify_signature(netdissect_options *ndo, + const struct ip *ip, const struct tcphdr *tp, + const u_char *data, u_int length, const u_char *rcvsig); #endif -static void print_tcp_rst_data(register const u_char *sp, u_int length); +static void print_tcp_rst_data(netdissect_options *, const u_char *sp, u_int length); +static void print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp, + u_int datalen); #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; + nd_ipv4 src; + nd_ipv4 dst; + u_int port; }; struct tcp_seq_hash { - struct tcp_seq_hash *nxt; - struct tha addr; - tcp_seq seq; - tcp_seq ack; + struct tcp_seq_hash *nxt; + struct tha addr; + uint32_t seq; + uint32_t ack; +}; + +struct tha6 { + nd_ipv6 src; + nd_ipv6 dst; + u_int port; +}; + +struct tcp_seq_hash6 { + struct tcp_seq_hash6 *nxt; + struct tha6 addr; + uint32_t seq; + uint32_t ack; }; #define TSEQ_HASHSIZE 919 -/* These tcp optinos do not have the size octet */ +/* These tcp options 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]; - +static struct tcp_seq_hash tcp_seq_hash4[TSEQ_HASHSIZE]; +static struct tcp_seq_hash6 tcp_seq_hash6[TSEQ_HASHSIZE]; + +const 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 } +}; -#ifndef TELNET_PORT -#define TELNET_PORT 23 -#endif -#ifndef BGP_PORT -#define BGP_PORT 179 -#endif -#define NETBIOS_SSN_PORT 139 -#ifndef PPTP_PORT -#define PPTP_PORT 1723 -#endif -#define BEEP_PORT 10288 -#ifndef NFS_PORT -#define NFS_PORT 2049 -#endif -#define MSDP_PORT 639 -#define LDP_PORT 646 +static const 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_SCPS, "scps" }, + { TCPOPT_UTO, "uto" }, + { TCPOPT_TCPAO, "tcp-ao" }, + { TCPOPT_MPTCP, "mptcp" }, + { TCPOPT_FASTOPEN, "tfo" }, + { TCPOPT_EXPERIMENT2, "exp" }, + { 0, NULL } +}; -static int tcp_cksum(register const struct ip *ip, - register const struct tcphdr *tp, - register u_int len) +static uint16_t +tcp_cksum(netdissect_options *ndo, + const struct ip *ip, + const struct tcphdr *tp, + u_int len) { - union phu { - struct phdr { - u_int32_t src; - u_int32_t dst; - u_char mbz; - u_char proto; - u_int16_t len; - } ph; - u_int16_t pa[6]; - } phu; - const u_int16_t *sp; - - /* pseudo-header.. */ - phu.ph.len = htons((u_int16_t)len); - phu.ph.mbz = 0; - phu.ph.proto = IPPROTO_TCP; - memcpy(&phu.ph.src, &ip->ip_src.s_addr, sizeof(u_int32_t)); - if (IP_HL(ip) == 5) - memcpy(&phu.ph.dst, &ip->ip_dst.s_addr, sizeof(u_int32_t)); - else - phu.ph.dst = ip_finddst(ip); - - sp = &phu.pa[0]; - return in_cksum((u_short *)tp, len, - sp[0]+sp[1]+sp[2]+sp[3]+sp[4]+sp[5]); + return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len, + IPPROTO_TCP); } -#ifdef INET6 -static int tcp6_cksum(const struct ip6_hdr *ip6, const struct tcphdr *tp, - u_int len) +static uint16_t +tcp6_cksum(netdissect_options *ndo, + const struct ip6_hdr *ip6, + const struct tcphdr *tp, + u_int len) { - size_t i; - u_int32_t sum = 0; - union { - struct { - struct in6_addr ph_src; - struct in6_addr ph_dst; - u_int32_t ph_len; - u_int8_t ph_zero[3]; - u_int8_t ph_nxt; - } ph; - u_int16_t pa[20]; - } phu; - - /* pseudo-header */ - memset(&phu, 0, sizeof(phu)); - phu.ph.ph_src = ip6->ip6_src; - phu.ph.ph_dst = ip6->ip6_dst; - phu.ph.ph_len = htonl(len); - phu.ph.ph_nxt = IPPROTO_TCP; - - for (i = 0; i < sizeof(phu.pa) / sizeof(phu.pa[0]); i++) - sum += phu.pa[i]; - - return in_cksum((u_short *)tp, len, sum); + return nextproto6_cksum(ndo, ip6, (const uint8_t *)tp, len, len, + IPPROTO_TCP); } -#endif void -tcp_print(register const u_char *bp, register u_int length, - register const u_char *bp2, int fragmented) +tcp_print(netdissect_options *ndo, + const u_char *bp, u_int length, + 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; - 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) { - if ((u_char *)tp + 4 + sizeof(struct sunrpc_msg) <= snapend && - dport == NFS_PORT) { - nfsreq_print((u_char *)tp + hlen + 4, length - hlen, - (u_char *)ip); - return; - } else if ((u_char *)tp + 4 + sizeof(struct sunrpc_msg) - <= snapend && - sport == NFS_PORT) { - nfsreply_print((u_char *)tp + hlen + 4, length - hlen, - (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; - } - if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH| - TH_ECNECHO|TH_CWR)) { - if (flags & TH_SYN) - putchar('S'); - if (flags & TH_FIN) - putchar('F'); - if (flags & TH_RST) - putchar('R'); - if (flags & TH_PUSH) - putchar('P'); - if (flags & TH_CWR) - putchar('W'); /* congestion _W_indow reduced (ECN) */ - if (flags & TH_ECNECHO) - putchar('E'); /* ecn _E_cho sent (ECN) */ - } else - putchar('.'); - - 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 - memset(&tha, 0, sizeof(tha)); - 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 { - 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 (IP_V(ip) == 4 && vflag && !Kflag && !fragmented) { - u_int16_t sum, tcp_sum; - if (TTEST2(tp->th_sport, length)) { - sum = tcp_cksum(ip, tp, length); - - (void)printf(", cksum 0x%04x",EXTRACT_16BITS(&tp->th_sum)); - if (sum != 0) { - tcp_sum = EXTRACT_16BITS(&tp->th_sum); - (void)printf(" (incorrect -> 0x%04x),",in_cksum_shouldbe(tcp_sum, sum)); - } else - (void)printf(" (correct),"); - } - } -#ifdef INET6 - if (IP_V(ip) == 6 && ip6->ip6_plen && vflag && !Kflag && !fragmented) { - u_int16_t sum,tcp_sum; - if (TTEST2(tp->th_sport, length)) { - sum = tcp6_cksum(ip6, tp, length); - (void)printf(", cksum 0x%04x",EXTRACT_16BITS(&tp->th_sum)); - if (sum != 0) { - tcp_sum = EXTRACT_16BITS(&tp->th_sum); - (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(" %u:%u(%u)", seq, seq + length, 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); - putchar(' '); - ch = '<'; - while (hlen > 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; + const struct tcphdr *tp; + const struct ip *ip; + u_char flags; + u_int hlen; + char ch; + uint16_t sport, dport, win, urp; + uint32_t seq, ack, thseq, thack; + u_int utoval; + uint16_t magic; + int rev; + const struct ip6_hdr *ip6; + u_int header_len; /* Header length in bytes */ + + ndo->ndo_protocol = "tcp"; + tp = (const struct tcphdr *)bp; + ip = (const struct ip *)bp2; + if (IP_V(ip) == 6) + ip6 = (const struct ip6_hdr *)bp2; + else + ip6 = NULL; + ch = '\0'; + if (!ND_TTEST_2(tp->th_dport)) { + if (ip6) { + ND_PRINT("%s > %s:", + GET_IP6ADDR_STRING(ip6->ip6_src), + GET_IP6ADDR_STRING(ip6->ip6_dst)); + } else { + ND_PRINT("%s > %s:", + GET_IPADDR_STRING(ip->ip_src), + GET_IPADDR_STRING(ip->ip_dst)); + } + nd_trunc_longjmp(ndo); + } + + sport = GET_BE_U_2(tp->th_sport); + dport = GET_BE_U_2(tp->th_dport); + + if (ip6) { + if (GET_U_1(ip6->ip6_nxt) == IPPROTO_TCP) { + ND_PRINT("%s.%s > %s.%s: ", + GET_IP6ADDR_STRING(ip6->ip6_src), + tcpport_string(ndo, sport), + GET_IP6ADDR_STRING(ip6->ip6_dst), + tcpport_string(ndo, dport)); + } else { + ND_PRINT("%s > %s: ", + tcpport_string(ndo, sport), tcpport_string(ndo, dport)); + } + } else { + if (GET_U_1(ip->ip_p) == IPPROTO_TCP) { + ND_PRINT("%s.%s > %s.%s: ", + GET_IPADDR_STRING(ip->ip_src), + tcpport_string(ndo, sport), + GET_IPADDR_STRING(ip->ip_dst), + tcpport_string(ndo, dport)); + } else { + ND_PRINT("%s > %s: ", + tcpport_string(ndo, sport), tcpport_string(ndo, dport)); + } + } + + hlen = TH_OFF(tp) * 4; + + if (hlen < sizeof(*tp)) { + ND_PRINT(" tcp %u [bad hdr length %u - too short, < %zu]", + length - hlen, hlen, sizeof(*tp)); + goto invalid; + } + + seq = GET_BE_U_4(tp->th_seq); + ack = GET_BE_U_4(tp->th_ack); + win = GET_BE_U_2(tp->th_win); + urp = GET_BE_U_2(tp->th_urp); + + if (ndo->ndo_qflag) { + ND_PRINT("tcp %u", length - hlen); + if (hlen > length) { + ND_PRINT(" [bad hdr length %u - too long, > %u]", + hlen, length); + goto invalid; + } + return; + } + + flags = GET_U_1(tp->th_flags); + ND_PRINT("Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags)); + + if (!ndo->ndo_Sflag && (flags & TH_ACK)) { + /* + * 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). + */ + rev = 0; + if (ip6) { + struct tcp_seq_hash6 *th; + struct tcp_seq_hash6 *tcp_seq_hash; + const void *src, *dst; + struct tha6 tha; + + tcp_seq_hash = tcp_seq_hash6; + src = (const void *)ip6->ip6_src; + dst = (const void *)ip6->ip6_dst; + if (sport > dport) + rev = 1; + else if (sport == dport) { + if (UNALIGNED_MEMCMP(src, dst, sizeof(ip6->ip6_dst)) > 0) + rev = 1; + } + if (rev) { + UNALIGNED_MEMCPY(&tha.src, dst, sizeof(ip6->ip6_dst)); + UNALIGNED_MEMCPY(&tha.dst, src, sizeof(ip6->ip6_src)); + tha.port = ((u_int)dport) << 16 | sport; + } else { + UNALIGNED_MEMCPY(&tha.dst, dst, sizeof(ip6->ip6_dst)); + UNALIGNED_MEMCPY(&tha.src, src, sizeof(ip6->ip6_src)); + tha.port = ((u_int)sport) << 16 | dport; + } + + 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 */ + /* calloc() return used by the 'tcp_seq_hash6' + hash table: do not free() */ + if (th->nxt == NULL) { + th->nxt = (struct tcp_seq_hash6 *) + calloc(1, sizeof(*th)); + if (th->nxt == NULL) + (*ndo->ndo_error)(ndo, + S_ERR_ND_MEM_ALLOC, + "%s: calloc", __func__); + } + 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 { + struct tcp_seq_hash *th; + struct tcp_seq_hash *tcp_seq_hash; + struct tha tha; + + tcp_seq_hash = tcp_seq_hash4; + if (sport > dport) + rev = 1; + else if (sport == dport) { + if (UNALIGNED_MEMCMP(ip->ip_src, ip->ip_dst, sizeof(ip->ip_dst)) > 0) + rev = 1; + } + if (rev) { + UNALIGNED_MEMCPY(&tha.src, ip->ip_dst, + sizeof(ip->ip_dst)); + UNALIGNED_MEMCPY(&tha.dst, ip->ip_src, + sizeof(ip->ip_src)); + tha.port = ((u_int)dport) << 16 | sport; + } else { + UNALIGNED_MEMCPY(&tha.dst, ip->ip_dst, + sizeof(ip->ip_dst)); + UNALIGNED_MEMCPY(&tha.src, ip->ip_src, + sizeof(ip->ip_src)); + tha.port = ((u_int)sport) << 16 | dport; + } + + 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 */ + /* calloc() return used by the 'tcp_seq_hash4' + hash table: do not free() */ + if (th->nxt == NULL) { + th->nxt = (struct tcp_seq_hash *) + calloc(1, sizeof(*th)); + if (th->nxt == NULL) + (*ndo->ndo_error)(ndo, + S_ERR_ND_MEM_ALLOC, + "%s: calloc", __func__); + } + 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 = rev = 0; + } + if (hlen > length) { + ND_PRINT(" [bad hdr length %u - too long, > %u]", + hlen, length); + goto invalid; + } + + if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) { + /* Check the checksum, if possible. */ + uint16_t sum, tcp_sum; + + if (IP_V(ip) == 4) { + if (ND_TTEST_LEN(tp->th_sport, length)) { + sum = tcp_cksum(ndo, ip, tp, length); + tcp_sum = GET_BE_U_2(tp->th_sum); + + ND_PRINT(", cksum 0x%04x", tcp_sum); + if (sum != 0) + ND_PRINT(" (incorrect -> 0x%04x)", + in_cksum_shouldbe(tcp_sum, sum)); + else + ND_PRINT(" (correct)"); + } + } else if (IP_V(ip) == 6) { + if (ND_TTEST_LEN(tp->th_sport, length)) { + sum = tcp6_cksum(ndo, ip6, tp, length); + tcp_sum = GET_BE_U_2(tp->th_sum); + + ND_PRINT(", cksum 0x%04x", tcp_sum); + if (sum != 0) + ND_PRINT(" (incorrect -> 0x%04x)", + in_cksum_shouldbe(tcp_sum, sum)); + else + ND_PRINT(" (correct)"); + + } + } + } + + length -= hlen; + if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) { + ND_PRINT(", seq %u", seq); + + if (length > 0) { + ND_PRINT(":%u", seq + length); + } + } + + if (flags & TH_ACK) { + ND_PRINT(", ack %u", ack); + } + + ND_PRINT(", win %u", win); + + if (flags & TH_URG) + ND_PRINT(", urg %u", urp); + /* + * Handle any options. + */ + if (hlen > sizeof(*tp)) { + const u_char *cp; + u_int i, opt, datalen; + u_int len; + + hlen -= sizeof(*tp); + cp = (const u_char *)tp + sizeof(*tp); + ND_PRINT(", options ["); + while (hlen > 0) { + if (ch != '\0') + ND_PRINT("%c", ch); + opt = GET_U_1(cp); + cp++; + if (ZEROLENOPT(opt)) + len = 1; + else { + len = GET_U_1(cp); + 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); } - - switch (opt) { - - case TCPOPT_MAXSEG: - (void)printf("mss"); - datalen = 2; - LENCHECK(datalen); - (void)printf(" %u", EXTRACT_16BITS(cp)); - - break; - - case TCPOPT_EOL: - (void)printf("eol"); - break; - - case TCPOPT_NOP: - (void)printf("nop"); - break; - - case TCPOPT_WSCALE: - (void)printf("wscale"); - datalen = 1; - LENCHECK(datalen); - (void)printf(" %u", *cp); - break; - - case TCPOPT_SACKOK: - (void)printf("sackOK"); - break; - - case TCPOPT_SACK: - datalen = len - 2; - if (datalen % 8 != 0) { - (void)printf("malformed sack"); - } else { - u_int32_t s, e; - - (void)printf("sack %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_ECHO: - (void)printf("echo"); - datalen = 4; - LENCHECK(datalen); - (void)printf(" %u", EXTRACT_32BITS(cp)); - break; - - case TCPOPT_ECHOREPLY: - (void)printf("echoreply"); - datalen = 4; - LENCHECK(datalen); - (void)printf(" %u", EXTRACT_32BITS(cp)); - break; - - case TCPOPT_TIMESTAMP: - (void)printf("timestamp"); - datalen = 8; - LENCHECK(4); - (void)printf(" %u", EXTRACT_32BITS(cp)); - LENCHECK(datalen); - (void)printf(" %u", EXTRACT_32BITS(cp + 4)); - break; - - case TCPOPT_CC: - (void)printf("cc"); - datalen = 4; - LENCHECK(datalen); - (void)printf(" %u", EXTRACT_32BITS(cp)); - break; - - case TCPOPT_CCNEW: - (void)printf("ccnew"); - datalen = 4; - LENCHECK(datalen); - (void)printf(" %u", EXTRACT_32BITS(cp)); - break; - - case TCPOPT_CCECHO: - (void)printf("ccecho"); - datalen = 4; - LENCHECK(datalen); - (void)printf(" %u", EXTRACT_32BITS(cp)); - break; - - case TCPOPT_SIGNATURE: - (void)printf("md5:"); - datalen = TCP_SIGLEN; - LENCHECK(datalen); +#define LENCHECK(l) { if ((l) > hlen) goto bad; } + + + ND_PRINT("%s", tok2str(tcp_option_values, "unknown-%u", opt)); + + switch (opt) { + + case TCPOPT_MAXSEG: + datalen = 2; + LENCHECK(datalen); + ND_PRINT(" %u", GET_BE_U_2(cp)); + break; + + case TCPOPT_WSCALE: + datalen = 1; + LENCHECK(datalen); + ND_PRINT(" %u", GET_U_1(cp)); + break; + + case TCPOPT_SACK: + datalen = len - 2; + if (datalen % 8 != 0) { + ND_PRINT(" invalid sack"); + } else { + uint32_t s, e; + + ND_PRINT(" %u ", datalen / 8); + for (i = 0; i < datalen; i += 8) { + LENCHECK(i + 4); + s = GET_BE_U_4(cp + i); + LENCHECK(i + 8); + e = GET_BE_U_4(cp + i + 4); + if (rev) { + s -= thseq; + e -= thseq; + } else { + s -= thack; + e -= thack; + } + ND_PRINT("{%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); + ND_PRINT(" %u", GET_BE_U_4(cp)); + break; + + case TCPOPT_TIMESTAMP: + datalen = 8; + LENCHECK(datalen); + ND_PRINT(" val %u ecr %u", + GET_BE_U_4(cp), + GET_BE_U_4(cp + 4)); + break; + + case TCPOPT_SIGNATURE: + datalen = TCP_SIGLEN; + LENCHECK(datalen); + ND_TCHECK_LEN(cp, datalen); + ND_PRINT(" "); #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; - } + switch (tcp_verify_signature(ndo, ip, tp, + bp + TH_OFF(tp) * 4, length, cp)) { + + case SIGNATURE_VALID: + ND_PRINT("valid"); + break; + + case SIGNATURE_INVALID: + nd_print_invalid(ndo); + break; + + case CANT_CHECK_SIGNATURE: + ND_PRINT("can't check - "); + for (i = 0; i < TCP_SIGLEN; ++i) + ND_PRINT("%02x", + GET_U_1(cp + i)); + break; + } #else - for (i = 0; i < TCP_SIGLEN; ++i) - (void)printf("%02x", cp[i]); + for (i = 0; i < TCP_SIGLEN; ++i) + ND_PRINT("%02x", GET_U_1(cp + i)); #endif - break; + break; + + case TCPOPT_SCPS: + datalen = 2; + LENCHECK(datalen); + ND_PRINT(" cap %02x id %u", GET_U_1(cp), + GET_U_1(cp + 1)); + break; + + case TCPOPT_TCPAO: + datalen = len - 2; + /* RFC 5925 Section 2.2: + * "The Length value MUST be greater than or equal to 4." + * (This includes the Kind and Length fields already processed + * at this point.) + */ + if (datalen < 2) { + nd_print_invalid(ndo); + } else { + LENCHECK(1); + ND_PRINT(" keyid %u", GET_U_1(cp)); + LENCHECK(2); + ND_PRINT(" rnextkeyid %u", + GET_U_1(cp + 1)); + if (datalen > 2) { + ND_PRINT(" mac 0x"); + for (i = 2; i < datalen; i++) { + LENCHECK(i + 1); + ND_PRINT("%02x", + GET_U_1(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 = GET_BE_U_2(cp); + ND_PRINT(" 0x%x", utoval); + if (utoval & 0x0001) + utoval = (utoval >> 1) * 60; + else + utoval >>= 1; + ND_PRINT(" %u", utoval); + break; + + case TCPOPT_MPTCP: + { + const u_char *snapend_save; + int ret; + + datalen = len - 2; + LENCHECK(datalen); + /* FIXME: Proof-read mptcp_print() and if it + * always covers all bytes when it returns 1, + * only do ND_TCHECK_LEN() if it returned 0. + */ + ND_TCHECK_LEN(cp, datalen); + /* Update the snapend to the end of the option + * before calling mptcp_print(). Some options + * (MPTCP or others) may be present after a + * MPTCP option. This prevents that, in + * mptcp_print(), the remaining length < the + * remaining caplen. + */ + snapend_save = ndo->ndo_snapend; + ndo->ndo_snapend = ND_MIN(cp - 2 + len, + ndo->ndo_snapend); + ret = mptcp_print(ndo, cp - 2, len, flags); + ndo->ndo_snapend = snapend_save; + if (!ret) + goto bad; + break; + } + + case TCPOPT_FASTOPEN: + datalen = len - 2; + LENCHECK(datalen); + ND_TCHECK_LEN(cp, datalen); + ND_PRINT(" "); + print_tcp_fastopen_option(ndo, cp, datalen); + break; + + case TCPOPT_EXPERIMENT2: + datalen = len - 2; + LENCHECK(datalen); + ND_TCHECK_LEN(cp, datalen); + if (datalen < 2) + goto bad; + /* RFC6994 */ + magic = GET_BE_U_2(cp); + ND_PRINT("-"); + + switch(magic) { + + case 0xf989: /* TCP Fast Open RFC 7413 */ + ND_PRINT("tfo"); + print_tcp_fastopen_option(ndo, cp + 2, datalen - 2); + break; + + default: + /* Unknown magic number */ + ND_PRINT("%04x", magic); + break; + } + break; - case TCPOPT_AUTH: - (void)printf("Enhanced Auth: keyid %d", *cp++); - datalen = len - 3; + default: + datalen = len - 2; + if (datalen) + ND_PRINT(" 0x"); for (i = 0; i < datalen; ++i) { - LENCHECK(i); - (void)printf("%02x", cp[i]); + LENCHECK(i + 1); + ND_PRINT("%02x", GET_U_1(cp + i)); } - break; - - default: - (void)printf("opt-%u:", opt); - 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('>'); - } - - if (length <= 0) - return; - - /* - * Decode payload if necessary. - */ - bp += TH_OFF(tp) * 4; - if (flags & TH_RST) { - if (vflag) - print_tcp_rst_data(bp, length); - } else { - 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); + 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) + ND_PRINT("[len %u]", len); + ch = ','; + if (opt == TCPOPT_EOL) + break; + } + ND_PRINT("]"); + } + + /* + * Print length field before crawling down the stack. + */ + ND_PRINT(", length %u", length); + + if (length <= 0) + return; + + /* + * Decode payload if necessary. + */ + header_len = TH_OFF(tp) * 4; + /* + * Do a bounds check before decoding the payload. + * At least the header data is required. + */ + if (!ND_TTEST_LEN(bp, header_len)) { + ND_PRINT(" [remaining caplen(%u) < header length(%u)]", + ND_BYTES_AVAILABLE_AFTER(bp), header_len); + nd_trunc_longjmp(ndo); + } + bp += header_len; + if ((flags & TH_RST) && ndo->ndo_vflag) { + print_tcp_rst_data(ndo, bp, length); + return; + } + + if (ndo->ndo_packettype) { + switch (ndo->ndo_packettype) { + case PT_ZMTP1: + zmtp1_print(ndo, bp, length); + break; + case PT_RESP: + resp_print(ndo, bp, length); + break; + case PT_DOMAIN: + /* over_tcp: TRUE, is_mdns: FALSE */ + domain_print(ndo, bp, length, TRUE, FALSE); + break; + } + return; + } + + if (IS_SRC_OR_DST_PORT(TELNET_PORT)) { + telnet_print(ndo, bp, length); + } else if (IS_SRC_OR_DST_PORT(SMTP_PORT)) { + ND_PRINT(": "); + smtp_print(ndo, bp, length); + } else if (IS_SRC_OR_DST_PORT(WHOIS_PORT)) { + ND_PRINT(": "); + ndo->ndo_protocol = "whois"; /* needed by txtproto_print() */ + txtproto_print(ndo, bp, length, NULL, 0); /* RFC 3912 */ + } else if (IS_SRC_OR_DST_PORT(BGP_PORT)) + bgp_print(ndo, bp, length); + else if (IS_SRC_OR_DST_PORT(PPTP_PORT)) + pptp_print(ndo, bp); + else if (IS_SRC_OR_DST_PORT(REDIS_PORT)) + resp_print(ndo, bp, length); + else if (IS_SRC_OR_DST_PORT(SSH_PORT)) + ssh_print(ndo, bp, length); +#ifdef ENABLE_SMB + else if (IS_SRC_OR_DST_PORT(NETBIOS_SSN_PORT)) + nbt_tcp_print(ndo, bp, length); + else if (IS_SRC_OR_DST_PORT(SMB_PORT)) + smb_tcp_print(ndo, 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 (length > 0 && (sport == LDP_PORT || dport == LDP_PORT)) { - ldp_print(bp, length); - } - } - return; + else if (IS_SRC_OR_DST_PORT(BEEP_PORT)) + beep_print(ndo, bp, length); + else if (IS_SRC_OR_DST_PORT(OPENFLOW_PORT_OLD) || IS_SRC_OR_DST_PORT(OPENFLOW_PORT_IANA)) + openflow_print(ndo, bp, length); + else if (IS_SRC_OR_DST_PORT(FTP_PORT)) { + ND_PRINT(": "); + ftp_print(ndo, bp, length); + } else if (IS_SRC_OR_DST_PORT(HTTP_PORT) || IS_SRC_OR_DST_PORT(HTTP_PORT_ALT)) { + ND_PRINT(": "); + http_print(ndo, bp, length); + } else if (IS_SRC_OR_DST_PORT(RTSP_PORT) || IS_SRC_OR_DST_PORT(RTSP_PORT_ALT)) { + ND_PRINT(": "); + rtsp_print(ndo, bp, length); + } else if (IS_SRC_OR_DST_PORT(NAMESERVER_PORT)) { + /* over_tcp: TRUE, is_mdns: FALSE */ + domain_print(ndo, bp, length, TRUE, FALSE); + } else if (IS_SRC_OR_DST_PORT(MSDP_PORT)) { + msdp_print(ndo, bp, length); + } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT)) { + rpki_rtr_print(ndo, bp, length); + } else if (IS_SRC_OR_DST_PORT(LDP_PORT)) { + ldp_print(ndo, bp, length); + } else if ((IS_SRC_OR_DST_PORT(NFS_PORT)) && + length >= 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. + */ + uint32_t fraglen; + const struct sunrpc_msg *rp; + enum sunrpc_msg_type direction; + + fraglen = GET_BE_U_4(bp) & 0x7FFFFFFF; + if (fraglen > (length) - 4) + fraglen = (length) - 4; + rp = (const struct sunrpc_msg *)(bp + 4); + if (ND_TTEST_4(rp->rm_direction)) { + direction = (enum sunrpc_msg_type) GET_BE_U_4(rp->rm_direction); + if (dport == NFS_PORT && direction == SUNRPC_CALL) { + ND_PRINT(": NFS request xid %u ", + GET_BE_U_4(rp->rm_xid)); + nfsreq_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip); + return; + } + if (sport == NFS_PORT && direction == SUNRPC_REPLY) { + ND_PRINT(": NFS reply xid %u ", + GET_BE_U_4(rp->rm_xid)); + nfsreply_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip); + return; + } + } + } + + return; bad: - fputs("[bad opt]", stdout); - if (ch != '\0') - putchar('>'); - return; -trunc: - fputs("[|tcp]", stdout); - if (ch != '\0') - putchar('>'); + ND_PRINT("[bad opt]"); + if (ch != '\0') + ND_PRINT("]"); + return; +invalid: + nd_print_invalid(ndo); } /* @@ -705,98 +850,120 @@ trunc: */ static void -print_tcp_rst_data(register const u_char *sp, u_int length) +print_tcp_rst_data(netdissect_options *ndo, + 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(']'); + ND_PRINT(ND_TTEST_LEN(sp, length) ? " [RST" : " [!RST"); + if (length > MAX_RST_DATA_LEN) { + length = MAX_RST_DATA_LEN; /* can use -X for longer */ + ND_PRINT("+"); /* indicate we truncate */ + } + ND_PRINT(" "); + (void)nd_printn(ndo, sp, length, ndo->ndo_snapend); + ND_PRINT("]"); +} + +static void +print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp, + u_int datalen) +{ + u_int i; + + if (datalen == 0) { + /* Fast Open Cookie Request */ + ND_PRINT(" cookiereq"); + } else { + /* Fast Open Cookie */ + if (datalen % 2 != 0 || datalen < 4 || datalen > 16) { + nd_print_invalid(ndo); + } else { + ND_PRINT(" cookie "); + for (i = 0; i < datalen; ++i) + ND_PRINT("%02x", GET_U_1(cp + i)); + } + } } #ifdef HAVE_LIBCRYPTO +DIAG_OFF_DEPRECATION static int -tcp_verify_signature(const struct ip *ip, const struct tcphdr *tp, - const u_char *data, int length, const u_char *rcvsig) +tcp_verify_signature(netdissect_options *ndo, + const struct ip *ip, const struct tcphdr *tp, + const u_char *data, u_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; -#endif - u_int32_t len32; - u_int8_t nxt; - - tp1 = *tp; - - if (tcpmd5secret == NULL) - 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(ntohs(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 - 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, tcpmd5secret, strlen(tcpmd5secret)); - MD5_Final(sig, &ctx); - - if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0) - return (SIGNATURE_VALID); - else - return (SIGNATURE_INVALID); + u_char sig[TCP_SIGLEN]; + char zero_proto = 0; + MD5_CTX ctx; + uint16_t savecsum, tlen; + const struct ip6_hdr *ip6; + uint32_t len32; + uint8_t nxt; + + if (!ND_TTEST_LEN(data, length)) { + ND_PRINT("snaplen too short, "); + return (CANT_CHECK_SIGNATURE); + } + + tp1 = *tp; + + if (ndo->ndo_sigsecret == NULL) { + ND_PRINT("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, (const char *)&ip->ip_src, sizeof(ip->ip_src)); + MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst)); + MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto)); + MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p)); + tlen = GET_BE_U_2(ip->ip_len) - IP_HL(ip) * 4; + tlen = htons(tlen); + MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen)); + } else if (IP_V(ip) == 6) { + ip6 = (const struct ip6_hdr *)ip; + MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src)); + MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst)); + len32 = htonl(GET_BE_U_2(ip6->ip6_plen)); + MD5_Update(&ctx, (const char *)&len32, sizeof(len32)); + nxt = 0; + MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt)); + MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt)); + MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt)); + nxt = IPPROTO_TCP; + MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt)); + } else { + ND_PRINT("IP version not 4 or 6, "); + return (CANT_CHECK_SIGNATURE); + } + + /* + * Step 2: Update MD5 hash with TCP header, excluding options. + * The TCP checksum must be set to zero. + */ + memcpy(&savecsum, tp1.th_sum, sizeof(savecsum)); + memset(tp1.th_sum, 0, sizeof(tp1.th_sum)); + MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr)); + memcpy(tp1.th_sum, &savecsum, sizeof(tp1.th_sum)); + /* + * 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, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret)); + MD5_Final(sig, &ctx); + + if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0) + return (SIGNATURE_VALID); + else + return (SIGNATURE_INVALID); } +DIAG_ON_DEPRECATION #endif /* HAVE_LIBCRYPTO */