mirror of
https://github.com/the-tcpdump-group/tcpdump.git
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988cd2bb0e
return -1 if they run out of data. Have the IPv4 and IPv6 dissectors check for non-positive return values from those routines and quit if they see one.
641 lines
15 KiB
C
641 lines
15 KiB
C
/*
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* Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that: (1) source code distributions
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* retain the above copyright notice and this paragraph in its entirety, (2)
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* distributions including binary code include the above copyright notice and
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* this paragraph in its entirety in the documentation or other materials
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* provided with the distribution, and (3) all advertising materials mentioning
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* features or use of this software display the following acknowledgement:
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* ``This product includes software developed by the University of California,
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* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
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* the University nor the names of its contributors may be used to endorse
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* or promote products derived from this software without specific prior
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* written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#ifndef lint
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static const char rcsid[] _U_ =
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"@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.132 2003-11-19 00:36:07 guy Exp $ (LBL)";
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#endif
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <tcpdump-stdinc.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "addrtoname.h"
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#include "interface.h"
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#include "extract.h" /* must come after interface.h */
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#include "ip.h"
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#include "ipproto.h"
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/*
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* print the recorded route in an IP RR, LSRR or SSRR option.
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*/
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static void
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ip_printroute(const char *type, register const u_char *cp, u_int length)
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{
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register u_int ptr = cp[2] - 1;
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register u_int len;
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printf(" %s{", type);
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if ((length + 1) & 3)
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printf(" [bad length %d]", length);
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if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
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printf(" [bad ptr %d]", cp[2]);
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type = "";
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for (len = 3; len < length; len += 4) {
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if (ptr == len)
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type = "#";
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printf("%s%s", type, ipaddr_string(&cp[len]));
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type = " ";
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}
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printf("%s}", ptr == len? "#" : "");
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}
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/*
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* If source-routing is present, return the final destination.
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* Otherwise, return IP destination.
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*
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* This is used for UDP and TCP pseudo-header in the checksum
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* calculation.
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*/
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u_int32_t
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ip_finddst(const struct ip *ip)
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{
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int length;
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int len;
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const u_char *cp;
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u_int32_t retval;
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cp = (const u_char *)(ip + 1);
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length = (IP_HL(ip) << 2) - sizeof(struct ip);
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for (; length > 0; cp += len, length -= len) {
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int tt = *cp;
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if (tt == IPOPT_NOP || tt == IPOPT_EOL)
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len = 1;
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else {
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if (&cp[1] >= snapend) {
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return 0;
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}
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len = cp[1];
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}
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if (len <= 0) {
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return 0;
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}
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if (&cp[1] >= snapend || cp + len > snapend) {
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return 0;
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}
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switch (tt) {
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case IPOPT_SSRR:
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case IPOPT_LSRR:
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memcpy(&retval, cp + len - 4, 4);
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return retval;
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}
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}
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return ip->ip_dst.s_addr;
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}
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static void
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ip_printts(register const u_char *cp, u_int length)
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{
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register u_int ptr = cp[2] - 1;
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register u_int len = 0;
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int hoplen;
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const char *type;
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printf(" TS{");
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hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
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if ((length - 4) & (hoplen-1))
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printf("[bad length %d]", length);
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if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
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printf("[bad ptr %d]", cp[2]);
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switch (cp[3]&0xF) {
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case IPOPT_TS_TSONLY:
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printf("TSONLY");
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break;
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case IPOPT_TS_TSANDADDR:
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printf("TS+ADDR");
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break;
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/*
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* prespecified should really be 3, but some ones might send 2
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* instead, and the IPOPT_TS_PRESPEC constant can apparently
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* have both values, so we have to hard-code it here.
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*/
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case 2:
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printf("PRESPEC2.0");
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break;
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case 3: /* IPOPT_TS_PRESPEC */
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printf("PRESPEC");
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break;
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default:
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printf("[bad ts type %d]", cp[3]&0xF);
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goto done;
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}
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type = " ";
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for (len = 4; len < length; len += hoplen) {
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if (ptr == len)
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type = " ^ ";
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printf("%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
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hoplen!=8 ? "" : ipaddr_string(&cp[len]));
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type = " ";
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}
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done:
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printf("%s", ptr == len ? " ^ " : "");
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if (cp[3]>>4)
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printf(" [%d hops not recorded]} ", cp[3]>>4);
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else
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printf("}");
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}
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/*
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* print IP options.
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*/
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static void
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ip_optprint(register const u_char *cp, u_int length)
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{
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register u_int len;
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for (; length > 0; cp += len, length -= len) {
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int tt = *cp;
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if (tt == IPOPT_NOP || tt == IPOPT_EOL)
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len = 1;
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else {
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if (&cp[1] >= snapend) {
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printf("[|ip]");
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return;
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}
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len = cp[1];
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}
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if (len <= 0) {
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printf("[|ip op len %d]", len);
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return;
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}
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if (&cp[1] >= snapend || cp + len > snapend) {
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printf("[|ip]");
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return;
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}
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switch (tt) {
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case IPOPT_EOL:
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printf(" EOL");
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if (length > 1)
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printf("-%d", length - 1);
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return;
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case IPOPT_NOP:
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printf(" NOP");
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break;
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case IPOPT_TS:
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ip_printts(cp, len);
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break;
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#ifndef IPOPT_SECURITY
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#define IPOPT_SECURITY 130
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#endif /* IPOPT_SECURITY */
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case IPOPT_SECURITY:
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printf(" SECURITY{%d}", len);
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break;
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case IPOPT_RR:
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ip_printroute("RR", cp, len);
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break;
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case IPOPT_SSRR:
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ip_printroute("SSRR", cp, len);
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break;
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case IPOPT_LSRR:
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ip_printroute("LSRR", cp, len);
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break;
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#ifndef IPOPT_RA
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#define IPOPT_RA 148 /* router alert */
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#endif
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case IPOPT_RA:
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printf(" RA");
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if (len != 4)
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printf("{%d}", len);
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else if (cp[2] || cp[3])
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printf("%d.%d", cp[2], cp[3]);
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break;
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default:
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printf(" IPOPT-%d{%d}", cp[0], len);
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break;
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}
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}
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}
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/*
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* compute an IP header checksum.
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* don't modifiy the packet.
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*/
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u_short
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in_cksum(const u_short *addr, register u_int len, int csum)
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{
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int nleft = len;
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const u_short *w = addr;
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u_short answer;
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int sum = csum;
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/*
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* Our algorithm is simple, using a 32 bit accumulator (sum),
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* we add sequential 16 bit words to it, and at the end, fold
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* back all the carry bits from the top 16 bits into the lower
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* 16 bits.
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*/
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while (nleft > 1) {
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sum += *w++;
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nleft -= 2;
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}
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if (nleft == 1)
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sum += htons(*(u_char *)w<<8);
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/*
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* add back carry outs from top 16 bits to low 16 bits
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*/
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sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
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sum += (sum >> 16); /* add carry */
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answer = ~sum; /* truncate to 16 bits */
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return (answer);
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}
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/*
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* Given the host-byte-order value of the checksum field in a packet
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* header, and the network-byte-order computed checksum of the data
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* that the checksum covers (including the checksum itself), compute
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* what the checksum field *should* have been.
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*/
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u_int16_t
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in_cksum_shouldbe(u_int16_t sum, u_int16_t computed_sum)
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{
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u_int32_t shouldbe;
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/*
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* The value that should have gone into the checksum field
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* is the negative of the value gotten by summing up everything
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* *but* the checksum field.
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*
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* We can compute that by subtracting the value of the checksum
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* field from the sum of all the data in the packet, and then
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* computing the negative of that value.
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*
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* "sum" is the value of the checksum field, and "computed_sum"
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* is the negative of the sum of all the data in the packets,
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* so that's -(-computed_sum - sum), or (sum + computed_sum).
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*
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* All the arithmetic in question is one's complement, so the
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* addition must include an end-around carry; we do this by
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* doing the arithmetic in 32 bits (with no sign-extension),
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* and then adding the upper 16 bits of the sum, which contain
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* the carry, to the lower 16 bits of the sum, and then do it
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* again in case *that* sum produced a carry.
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*
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* As RFC 1071 notes, the checksum can be computed without
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* byte-swapping the 16-bit words; summing 16-bit words
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* on a big-endian machine gives a big-endian checksum, which
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* can be directly stuffed into the big-endian checksum fields
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* in protocol headers, and summing words on a little-endian
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* machine gives a little-endian checksum, which must be
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* byte-swapped before being stuffed into a big-endian checksum
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* field.
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*
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* "computed_sum" is a network-byte-order value, so we must put
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* it in host byte order before subtracting it from the
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* host-byte-order value from the header; the adjusted checksum
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* will be in host byte order, which is what we'll return.
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*/
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shouldbe = sum;
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shouldbe += ntohs(computed_sum);
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shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
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shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
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return shouldbe;
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}
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#ifndef IP_MF
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#define IP_MF 0x2000
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#endif /* IP_MF */
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#ifndef IP_DF
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#define IP_DF 0x4000
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#endif /* IP_DF */
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#define IP_RES 0x8000
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static struct tok ip_frag_values[] = {
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{ IP_MF, "+" },
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{ IP_DF, "DF" },
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{ IP_RES, "rsvd" }, /* The RFC3514 evil ;-) bit */
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{ 0, NULL }
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};
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/*
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* print an IP datagram.
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*/
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void
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ip_print(register const u_char *bp, register u_int length)
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{
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register const struct ip *ip;
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register u_int hlen, len, len0, off;
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const u_char *ipend;
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register const u_char *cp;
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u_char nh;
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int advance;
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struct protoent *proto;
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u_int16_t sum, ip_sum;
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ip = (const struct ip *)bp;
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if (IP_V(ip) != 4) { /* print version if != 4 */
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printf("IP%u ", IP_V(ip));
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if (IP_V(ip) == 6)
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printf(", wrong link-layer encapsulation");
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}
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else
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printf("IP ");
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if ((u_char *)(ip + 1) > snapend) {
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printf("[|ip]");
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return;
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}
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if (length < sizeof (struct ip)) {
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(void)printf("truncated-ip %d", length);
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return;
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}
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hlen = IP_HL(ip) * 4;
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if (hlen < sizeof (struct ip)) {
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(void)printf("bad-hlen %u", hlen);
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return;
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}
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len = EXTRACT_16BITS(&ip->ip_len);
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if (length < len)
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(void)printf("truncated-ip - %u bytes missing! ",
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len - length);
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if (len < hlen) {
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(void)printf("bad-len %u", len);
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return;
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}
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/*
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* Cut off the snapshot length to the end of the IP payload.
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*/
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ipend = bp + len;
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if (ipend < snapend)
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snapend = ipend;
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len -= hlen;
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len0 = len;
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off = EXTRACT_16BITS(&ip->ip_off);
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if (vflag) {
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(void)printf("(tos 0x%x", (int)ip->ip_tos);
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/* ECN bits */
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if (ip->ip_tos & 0x03) {
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switch (ip->ip_tos & 0x03) {
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case 1:
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(void)printf(",ECT(1)");
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break;
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case 2:
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(void)printf(",ECT(0)");
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break;
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case 3:
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(void)printf(",CE");
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}
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}
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if (ip->ip_ttl >= 1)
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(void)printf(", ttl %3u", ip->ip_ttl);
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/*
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* for the firewall guys, print id, offset.
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* On all but the last stick a "+" in the flags portion.
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* For unfragmented datagrams, note the don't fragment flag.
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*/
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(void)printf(", id %u, offset %u, flags [%s]",
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EXTRACT_16BITS(&ip->ip_id),
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(off & 0x1fff) * 8,
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bittok2str(ip_frag_values, "none", off & 0xe000 ));
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(void)printf(", length: %u", EXTRACT_16BITS(&ip->ip_len));
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if ((hlen - sizeof(struct ip)) > 0) {
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(void)printf(", optlength: %u (", hlen - (u_int)sizeof(struct ip));
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ip_optprint((u_char *)(ip + 1), hlen - sizeof(struct ip));
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printf(" )");
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}
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if ((u_char *)ip + hlen <= snapend) {
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sum = in_cksum((const u_short *)ip, hlen, 0);
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if (sum != 0) {
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ip_sum = EXTRACT_16BITS(&ip->ip_sum);
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(void)printf(", bad cksum %x (->%x)!", ip_sum,
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in_cksum_shouldbe(ip_sum, sum));
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}
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}
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printf(") ");
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}
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/*
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* If this is fragment zero, hand it to the next higher
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* level protocol.
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*/
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if ((off & 0x1fff) == 0) {
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cp = (const u_char *)ip + hlen;
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nh = ip->ip_p;
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if (nh != IPPROTO_TCP && nh != IPPROTO_UDP &&
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nh != IPPROTO_SCTP) {
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(void)printf("%s > %s: ", ipaddr_string(&ip->ip_src),
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ipaddr_string(&ip->ip_dst));
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}
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again:
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switch (nh) {
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case IPPROTO_AH:
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nh = *cp;
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advance = ah_print(cp);
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if (advance <= 0)
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break;
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cp += advance;
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len -= advance;
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goto again;
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case IPPROTO_ESP:
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{
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int enh, padlen;
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advance = esp_print(cp, (const u_char *)ip, &enh, &padlen);
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if (advance <= 0)
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break;
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cp += advance;
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len -= advance + padlen;
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nh = enh & 0xff;
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goto again;
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}
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case IPPROTO_IPCOMP:
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{
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int enh;
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advance = ipcomp_print(cp, &enh);
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if (advance <= 0)
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break;
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cp += advance;
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len -= advance;
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nh = enh & 0xff;
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goto again;
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}
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case IPPROTO_SCTP:
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sctp_print(cp, (const u_char *)ip, len);
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break;
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case IPPROTO_TCP:
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tcp_print(cp, len, (const u_char *)ip, (off &~ 0x6000));
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break;
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case IPPROTO_UDP:
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udp_print(cp, len, (const u_char *)ip, (off &~ 0x6000));
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break;
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case IPPROTO_ICMP:
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/* pass on the MF bit plus the offset to detect fragments */
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icmp_print(cp, len, (const u_char *)ip, (off & 0x3fff));
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break;
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case IPPROTO_IGRP:
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igrp_print(cp, len, (const u_char *)ip);
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break;
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case IPPROTO_ND:
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(void)printf(" nd %d", len);
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break;
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case IPPROTO_EGP:
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egp_print(cp);
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break;
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case IPPROTO_OSPF:
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ospf_print(cp, len, (const u_char *)ip);
|
|
break;
|
|
|
|
case IPPROTO_IGMP:
|
|
igmp_print(cp, len);
|
|
break;
|
|
|
|
case IPPROTO_IPV4:
|
|
/* DVMRP multicast tunnel (ip-in-ip encapsulation) */
|
|
ip_print(cp, len);
|
|
if (! vflag) {
|
|
printf(" (ipip-proto-4)");
|
|
return;
|
|
}
|
|
break;
|
|
|
|
#ifdef INET6
|
|
case IPPROTO_IPV6:
|
|
/* ip6-in-ip encapsulation */
|
|
ip6_print(cp, len);
|
|
break;
|
|
#endif /*INET6*/
|
|
|
|
case IPPROTO_RSVP:
|
|
rsvp_print(cp, len);
|
|
break;
|
|
|
|
case IPPROTO_GRE:
|
|
/* do it */
|
|
gre_print(cp, len);
|
|
break;
|
|
|
|
case IPPROTO_MOBILE:
|
|
mobile_print(cp, len);
|
|
break;
|
|
|
|
case IPPROTO_PIM:
|
|
pim_print(cp, len);
|
|
break;
|
|
|
|
case IPPROTO_VRRP:
|
|
vrrp_print(cp, len, ip->ip_ttl);
|
|
break;
|
|
|
|
default:
|
|
if ((proto = getprotobynumber(nh)) != NULL)
|
|
(void)printf(" %s", proto->p_name);
|
|
else
|
|
(void)printf(" ip-proto-%d", nh);
|
|
printf(" %d", len);
|
|
break;
|
|
}
|
|
} else {
|
|
/* Ultra quiet now means that all this stuff should be suppressed */
|
|
if (qflag > 1) return;
|
|
|
|
/*
|
|
* if this isn't the first frag, we're missing the
|
|
* next level protocol header. print the ip addr
|
|
* and the protocol.
|
|
*/
|
|
if (off & 0x1fff) {
|
|
(void)printf("%s > %s:", ipaddr_string(&ip->ip_src),
|
|
ipaddr_string(&ip->ip_dst));
|
|
if ((proto = getprotobynumber(ip->ip_p)) != NULL)
|
|
(void)printf(" %s", proto->p_name);
|
|
else
|
|
(void)printf(" ip-proto-%d", ip->ip_p);
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
ipN_print(register const u_char *bp, register u_int length)
|
|
{
|
|
struct ip *ip, hdr;
|
|
|
|
ip = (struct ip *)bp;
|
|
if (length < 4) {
|
|
(void)printf("truncated-ip %d", length);
|
|
return;
|
|
}
|
|
memcpy (&hdr, (char *)ip, 4);
|
|
switch (IP_V(&hdr)) {
|
|
case 4:
|
|
ip_print (bp, length);
|
|
return;
|
|
#ifdef INET6
|
|
case 6:
|
|
ip6_print (bp, length);
|
|
return;
|
|
#endif
|
|
default:
|
|
(void)printf("unknown ip %d", IP_V(&hdr));
|
|
return;
|
|
}
|
|
}
|
|
|
|
|
|
|