mirror of
https://github.com/the-tcpdump-group/tcpdump.git
synced 2024-11-27 20:14:12 +08:00
7039327875
Report if it's not, and don't use it as an out-of-bounds index into an array. This fixes a buffer overflow discovered by Wilfried Kirsch. Add a test using the capture file supplied by the reporter(s), modified so the capture file won't be rejected as an invalid capture.
277 lines
6.6 KiB
C
277 lines
6.6 KiB
C
/*
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* Copyright (c) 1989, 1990, 1991, 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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/* \summary: Compressed Serial Line Internet Protocol printer */
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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 <netdissect-stdinc.h>
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#include "netdissect.h"
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#include "extract.h"
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#include "ip.h"
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#include "tcp.h"
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#include "slcompress.h"
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/*
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* definitions of the pseudo- link-level header attached to slip
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* packets grabbed by the packet filter (bpf) traffic monitor.
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*/
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#define SLIP_HDRLEN 16
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#define SLX_DIR 0
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#define SLX_CHDR 1
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#define CHDR_LEN 15
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#define SLIPDIR_IN 0
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#define SLIPDIR_OUT 1
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static const char tstr[] = "[|slip]";
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static u_int lastlen[2][256];
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static u_int lastconn = 255;
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static void sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int);
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static void compressed_sl_print(netdissect_options *, const u_char *, const struct ip *, u_int, int);
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u_int
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sl_if_print(netdissect_options *ndo,
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const struct pcap_pkthdr *h, const u_char *p)
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{
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register u_int caplen = h->caplen;
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register u_int length = h->len;
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register const struct ip *ip;
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if (caplen < SLIP_HDRLEN || length < SLIP_HDRLEN) {
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ND_PRINT((ndo, "%s", tstr));
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return (caplen);
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}
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caplen -= SLIP_HDRLEN;
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length -= SLIP_HDRLEN;
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ip = (const struct ip *)(p + SLIP_HDRLEN);
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if (ndo->ndo_eflag)
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sliplink_print(ndo, p, ip, length);
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if (caplen < 1 || length < 1) {
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ND_PRINT((ndo, "%s", tstr));
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return (caplen + SLIP_HDRLEN);
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}
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switch (IP_V(ip)) {
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case 4:
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ip_print(ndo, (const u_char *)ip, length);
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break;
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case 6:
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ip6_print(ndo, (const u_char *)ip, length);
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break;
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default:
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ND_PRINT((ndo, "ip v%d", IP_V(ip)));
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}
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return (SLIP_HDRLEN);
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}
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u_int
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sl_bsdos_if_print(netdissect_options *ndo,
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const struct pcap_pkthdr *h, const u_char *p)
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{
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register u_int caplen = h->caplen;
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register u_int length = h->len;
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register const struct ip *ip;
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if (caplen < SLIP_HDRLEN) {
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ND_PRINT((ndo, "%s", tstr));
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return (caplen);
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}
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length -= SLIP_HDRLEN;
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ip = (const struct ip *)(p + SLIP_HDRLEN);
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#ifdef notdef
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if (ndo->ndo_eflag)
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sliplink_print(ndo, p, ip, length);
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#endif
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ip_print(ndo, (const u_char *)ip, length);
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return (SLIP_HDRLEN);
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}
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static void
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sliplink_print(netdissect_options *ndo,
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register const u_char *p, register const struct ip *ip,
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register u_int length)
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{
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int dir;
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u_int hlen;
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dir = p[SLX_DIR];
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switch (dir) {
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case SLIPDIR_IN:
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ND_PRINT((ndo, "I "));
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break;
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case SLIPDIR_OUT:
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ND_PRINT((ndo, "O "));
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break;
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default:
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ND_PRINT((ndo, "Invalid direction %d ", dir));
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dir = -1;
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break;
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}
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if (ndo->ndo_nflag) {
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/* XXX just dump the header */
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register int i;
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for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i)
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ND_PRINT((ndo, "%02x.", p[i]));
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ND_PRINT((ndo, "%02x: ", p[SLX_CHDR + CHDR_LEN - 1]));
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return;
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}
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switch (p[SLX_CHDR] & 0xf0) {
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case TYPE_IP:
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ND_PRINT((ndo, "ip %d: ", length + SLIP_HDRLEN));
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break;
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case TYPE_UNCOMPRESSED_TCP:
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/*
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* The connection id is stored in the IP protocol field.
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* Get it from the link layer since sl_uncompress_tcp()
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* has restored the IP header copy to IPPROTO_TCP.
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*/
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lastconn = ((const struct ip *)&p[SLX_CHDR])->ip_p;
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ND_PRINT((ndo, "utcp %d: ", lastconn));
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if (dir == -1) {
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/* Direction is bogus, don't use it */
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return;
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}
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hlen = IP_HL(ip);
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hlen += TH_OFF((const struct tcphdr *)&((const int *)ip)[hlen]);
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lastlen[dir][lastconn] = length - (hlen << 2);
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break;
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default:
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if (dir == -1) {
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/* Direction is bogus, don't use it */
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return;
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}
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if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) {
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compressed_sl_print(ndo, &p[SLX_CHDR], ip,
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length, dir);
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ND_PRINT((ndo, ": "));
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} else
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ND_PRINT((ndo, "slip-%d!: ", p[SLX_CHDR]));
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}
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}
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static const u_char *
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print_sl_change(netdissect_options *ndo,
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const char *str, register const u_char *cp)
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{
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register u_int i;
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if ((i = *cp++) == 0) {
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i = EXTRACT_16BITS(cp);
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cp += 2;
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}
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ND_PRINT((ndo, " %s%d", str, i));
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return (cp);
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}
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static const u_char *
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print_sl_winchange(netdissect_options *ndo,
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register const u_char *cp)
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{
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register short i;
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if ((i = *cp++) == 0) {
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i = EXTRACT_16BITS(cp);
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cp += 2;
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}
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if (i >= 0)
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ND_PRINT((ndo, " W+%d", i));
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else
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ND_PRINT((ndo, " W%d", i));
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return (cp);
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}
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static void
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compressed_sl_print(netdissect_options *ndo,
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const u_char *chdr, const struct ip *ip,
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u_int length, int dir)
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{
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register const u_char *cp = chdr;
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register u_int flags, hlen;
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flags = *cp++;
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if (flags & NEW_C) {
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lastconn = *cp++;
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ND_PRINT((ndo, "ctcp %d", lastconn));
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} else
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ND_PRINT((ndo, "ctcp *"));
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/* skip tcp checksum */
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cp += 2;
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switch (flags & SPECIALS_MASK) {
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case SPECIAL_I:
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ND_PRINT((ndo, " *SA+%d", lastlen[dir][lastconn]));
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break;
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case SPECIAL_D:
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ND_PRINT((ndo, " *S+%d", lastlen[dir][lastconn]));
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break;
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default:
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if (flags & NEW_U)
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cp = print_sl_change(ndo, "U=", cp);
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if (flags & NEW_W)
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cp = print_sl_winchange(ndo, cp);
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if (flags & NEW_A)
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cp = print_sl_change(ndo, "A+", cp);
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if (flags & NEW_S)
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cp = print_sl_change(ndo, "S+", cp);
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break;
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}
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if (flags & NEW_I)
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cp = print_sl_change(ndo, "I+", cp);
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/*
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* 'hlen' is the length of the uncompressed TCP/IP header (in words).
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* 'cp - chdr' is the length of the compressed header.
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* 'length - hlen' is the amount of data in the packet.
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*/
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hlen = IP_HL(ip);
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hlen += TH_OFF((const struct tcphdr *)&((const int32_t *)ip)[hlen]);
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lastlen[dir][lastconn] = length - (hlen << 2);
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ND_PRINT((ndo, " %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr)));
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}
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