print-tcp.c

来自「TCPDUMP的C语言源代码,是在数据链路层的应用」· C语言 代码 · 共 819 行 · 第 1/2 页

/*	$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 1.130.2.3 2007-12-22 03:08:45 guy 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 <tcpdump-stdinc.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#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 <openssl/md5.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);
#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" },
        { 0, NULL }
};

static int tcp_cksum(register const struct ip *ip,
		     register const struct tcphdr *tp,
		     register 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]);
}

#ifdef INET6
static int tcp6_cksum(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);
}
#endif

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;
        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
                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)