X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/3cd171317f54bc968808d49e3ca87b6c49ccdcdd..cbd4cbb99cf9e68c67af16b5b20a050ef8819af6:/print-tcp.c diff --git a/print-tcp.c b/print-tcp.c index fa209918..eecf0b48 100644 --- a/print-tcp.c +++ b/print-tcp.c @@ -21,7 +21,7 @@ #ifndef lint static const char rcsid[] = - "@(#) $Header: /tcpdump/master/tcpdump/print-tcp.c,v 1.67 2000-07-01 03:39:10 assar Exp $ (LBL)"; + "@(#) $Header: /tcpdump/master/tcpdump/print-tcp.c,v 1.86 2001-05-09 01:16:57 fenner Exp $ (LBL)"; #endif #ifdef HAVE_CONFIG_H @@ -34,64 +34,31 @@ static const char rcsid[] = #include #include -#include -#include -#include -#include #include #include #include +#include #include -#ifdef INET6 -#include -#endif - #include "interface.h" #include "addrtoname.h" #include "extract.h" -/* Compatibility */ -#ifndef TCPOPT_WSCALE -#define TCPOPT_WSCALE 3 /* window scale factor (rfc1072) */ -#endif -#ifndef TCPOPT_SACKOK -#define TCPOPT_SACKOK 4 /* selective ack ok (rfc1072) */ -#endif -#ifndef TCPOPT_SACK -#define TCPOPT_SACK 5 /* selective ack (rfc1072) */ -#endif -#ifndef TCPOPT_ECHO -#define TCPOPT_ECHO 6 /* echo (rfc1072) */ -#endif -#ifndef TCPOPT_ECHOREPLY -#define TCPOPT_ECHOREPLY 7 /* echo (rfc1072) */ -#endif -#ifndef TCPOPT_TIMESTAMP -#define TCPOPT_TIMESTAMP 8 /* timestamps (rfc1323) */ -#endif -#ifndef TCPOPT_CC -#define TCPOPT_CC 11 /* T/TCP CC options (rfc1644) */ -#endif -#ifndef TCPOPT_CCNEW -#define TCPOPT_CCNEW 12 /* T/TCP CC options (rfc1644) */ -#endif -#ifndef TCPOPT_CCECHO -#define TCPOPT_CCECHO 13 /* T/TCP CC options (rfc1644) */ -#endif +#include "tcp.h" -/* - * Definitions required for ECN - * for use if the OS running tcpdump does not have ECN - */ -#ifndef TH_ECNECHO -#define TH_ECNECHO 0x40 /* ECN Echo in tcp header */ -#endif -#ifndef TH_CWR -#define TH_CWR 0x80 /* ECN Cwnd Reduced in tcp header*/ +#include "ip.h" +#ifdef INET6 +#include "ip6.h" #endif +#include "nameser.h" + +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; @@ -125,13 +92,110 @@ static struct tcp_seq_hash tcp_seq_hash[TSEQ_HASHSIZE]; #define BGP_PORT 179 #endif #define NETBIOS_SSN_PORT 139 +#ifndef PPTP_PORT +#define PPTP_PORT 1723 +#endif +#define BXXP_PORT 10288 #ifndef NFS_PORT #define NFS_PORT 2049 #endif +static int tcp_cksum(register const struct ip *ip, + register const struct tcphdr *tp, + register int len) +{ + int i, tlen; + 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; + register const u_int16_t *sp; + u_int32_t sum; + tlen = ntohs(ip->ip_len) - ((const char *)tp-(const char*)ip); + + /* pseudo-header.. */ + phu.ph.len = htons(tlen); + phu.ph.mbz = 0; + phu.ph.proto = IPPROTO_TCP; + memcpy(&phu.ph.src, &ip->ip_src.s_addr, sizeof(u_int32_t)); + memcpy(&phu.ph.dst, &ip->ip_dst.s_addr, sizeof(u_int32_t)); + + sp = &phu.pa[0]; + sum = sp[0]+sp[1]+sp[2]+sp[3]+sp[4]+sp[5]; + + sp = (const u_int16_t *)tp; + + for (i=0; i<(tlen&~1); i+= 2) + sum += *sp++; + + if (tlen & 1) { + sum += htons( (*(const u_int8_t *)sp) << 8); + } + + while (sum > 0xffff) + sum = (sum & 0xffff) + (sum >> 16); + sum = ~sum & 0xffff; + + return (sum); +} + +#ifdef INET6 +static int tcp6_cksum(const struct ip6_hdr *ip6, const struct tcphdr *tp, + int len) +{ + int i, tlen; + register const u_int16_t *sp; + u_int32_t sum; + 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; + + tlen = ntohs(ip6->ip6_plen) + sizeof(struct ip6_hdr) - + ((const char *)tp - (const char*)ip6); + + /* 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(tlen); + phu.ph.ph_nxt = IPPROTO_TCP; + + sum = 0; + for (i = 0; i < sizeof(phu.pa) / sizeof(phu.pa[0]); i++) + sum += phu.pa[i]; + + sp = (const u_int16_t *)tp; + + for (i = 0; i < (tlen & ~1); i += 2) + sum += *sp++; + + if (tlen & 1) + sum += htons((*(const u_int8_t *)sp) << 8); + + while (sum > 0xffff) + sum = (sum & 0xffff) + (sum >> 16); + sum = ~sum & 0xffff; + + return (sum); +} +#endif + void tcp_print(register const u_char *bp, register u_int length, - register const u_char *bp2) + register const u_char *bp2, int fragmented) { register const struct tcphdr *tp; register const struct ip *ip; @@ -148,7 +212,7 @@ tcp_print(register const u_char *bp, register u_int length, tp = (struct tcphdr *)bp; ip = (struct ip *)bp2; #ifdef INET6 - if (ip->ip_v == 6) + if (IP_V(ip) == 6) ip6 = (struct ip6_hdr *)bp2; else ip6 = NULL; @@ -165,7 +229,7 @@ tcp_print(register const u_char *bp, register u_int length, dport = ntohs(tp->th_dport); - hlen = tp->th_off * 4; + hlen = TH_OFF(tp) * 4; /* * If data present and NFS port used, assume NFS. @@ -175,7 +239,7 @@ tcp_print(register const u_char *bp, register u_int length, if (!qflag) { if ((u_char *)tp + 4 + sizeof(struct rpc_msg) <= snapend && dport == NFS_PORT) { - nfsreq_print((u_char *)tp + hlen + 4, length-hlen, + nfsreq_print((u_char *)tp + hlen + 4, length - hlen, (u_char *)ip); return; } else if ((u_char *)tp + 4 + sizeof(struct rpc_msg) @@ -221,7 +285,7 @@ tcp_print(register const u_char *bp, register u_int length, urp = ntohs(tp->th_urp); if (qflag) { - (void)printf("tcp %d", length - tp->th_off * 4); + (void)printf("tcp %d", length - TH_OFF(tp) * 4); return; } if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH| @@ -252,21 +316,21 @@ tcp_print(register const u_char *bp, register u_int length, * both directions). */ #ifdef INET6 - bzero(&tha, sizeof(tha)); + memset(&tha, 0, sizeof(tha)); rev = 0; if (ip6) { - if (sport > dport) { + if (sport > dport) rev = 1; - } else if (sport == dport) { - int i; - - for (i = 0; i < 4; i++) { - if (((u_int32_t *)(&ip6->ip6_src))[i] > - ((u_int32_t *)(&ip6->ip6_dst))[i]) { - rev = 1; - break; + else if (sport == dport) { + int i; + + for (i = 0; i < 4; i++) { + if (((u_int32_t *)(&ip6->ip6_src))[i] > + ((u_int32_t *)(&ip6->ip6_dst))[i]) { + rev = 1; + break; + } } - } } if (rev) { tha.src = ip6->ip6_dst; @@ -327,7 +391,6 @@ tcp_print(register const u_char *bp, register u_int length, th->ack = seq, th->seq = ack - 1; else th->seq = seq, th->ack = ack - 1; - } else { if (rev) seq -= th->ack, ack -= th->seq; @@ -345,6 +408,30 @@ tcp_print(register const u_char *bp, register u_int length, (void)printf(" [bad hdr length]"); return; } + + if (IP_V(ip) == 4 && vflag && !fragmented) { + int sum; + if (TTEST2(tp->th_sport, length)) { + sum = tcp_cksum(ip, tp, length); + if (sum != 0) + (void)printf(" [bad tcp cksum %x!]", sum); + else + (void)printf(" [tcp sum ok]"); + } + } +#ifdef INET6 + if (IP_V(ip) == 6 && ip6->ip6_plen && vflag && !fragmented) { + int sum; + if (TTEST2(tp->th_sport, length)) { + sum = tcp6_cksum(ip6, tp, length); + if (sum != 0) + (void)printf(" [bad tcp cksum %x!]", sum); + else + (void)printf(" [tcp sum ok]"); + } + } +#endif + length -= hlen; if (vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) (void)printf(" %u:%u(%d)", seq, seq + length, length); @@ -517,14 +604,28 @@ tcp_print(register const u_char *bp, register u_int length, /* * Decode payload if necessary. */ - bp += (tp->th_off * 4); - if (!qflag && vflag && length > 0 - && (sport == TELNET_PORT || dport == TELNET_PORT)) - telnet_print(bp, length); - else if (sport == BGP_PORT || dport == BGP_PORT) - bgp_print(bp, length); - else if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT) - nbt_tcp_print(bp, length); + 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, length); + else if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT) + nbt_tcp_print(bp, length); + else if (sport == BXXP_PORT || dport == BXXP_PORT) + bxxp_print(bp, length); + else if (length > 2 && + (sport == NAMESERVER_PORT || dport == NAMESERVER_PORT)) { + /* TCP DNS query has 2byte length at the head */ + ns_print(bp + 2, length - 2); + } + } return; bad: fputs("[bad opt]", stdout); @@ -537,3 +638,38 @@ trunc: 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(']'); +}