nexmon – Rev 1
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/*
* Copyright (c) 1989, 1990, 1991, 1993, 1994, 1995, 1996, 1997
* The Regents of the University of California. All rights reserved.
*
* 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.
*/
#define NETDISSECT_REWORKED
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <tcpdump-stdinc.h>
#include "interface.h"
#include "extract.h" /* must come after interface.h */
#include "ip.h"
#include "tcp.h"
#include "slcompress.h"
/*
* definitions of the pseudo- link-level header attached to slip
* packets grabbed by the packet filter (bpf) traffic monitor.
*/
#define SLIP_HDRLEN 16
#define SLX_DIR 0
#define SLX_CHDR 1
#define CHDR_LEN 15
#define SLIPDIR_IN 0
#define SLIPDIR_OUT 1
static const char tstr[] = "[|slip]";
static u_int lastlen[2][256];
static u_int lastconn = 255;
static void sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int);
static void compressed_sl_print(netdissect_options *, const u_char *, const struct ip *, u_int, int);
u_int
sl_if_print(netdissect_options *ndo,
const struct pcap_pkthdr *h, const u_char *p)
{
register u_int caplen = h->caplen;
register u_int length = h->len;
register const struct ip *ip;
if (caplen < SLIP_HDRLEN || length < SLIP_HDRLEN) {
ND_PRINT((ndo, "%s", tstr));
return (caplen);
}
length -= SLIP_HDRLEN;
ip = (struct ip *)(p + SLIP_HDRLEN);
if (ndo->ndo_eflag)
sliplink_print(ndo, p, ip, length);
switch (IP_V(ip)) {
case 4:
ip_print(ndo, (u_char *)ip, length);
break;
case 6:
ip6_print(ndo, (u_char *)ip, length);
break;
default:
ND_PRINT((ndo, "ip v%d", IP_V(ip)));
}
return (SLIP_HDRLEN);
}
u_int
sl_bsdos_if_print(netdissect_options *ndo,
const struct pcap_pkthdr *h, const u_char *p)
{
register u_int caplen = h->caplen;
register u_int length = h->len;
register const struct ip *ip;
if (caplen < SLIP_HDRLEN) {
ND_PRINT((ndo, "%s", tstr));
return (caplen);
}
length -= SLIP_HDRLEN;
ip = (struct ip *)(p + SLIP_HDRLEN);
#ifdef notdef
if (ndo->ndo_eflag)
sliplink_print(ndo, p, ip, length);
#endif
ip_print(ndo, (u_char *)ip, length);
return (SLIP_HDRLEN);
}
static void
sliplink_print(netdissect_options *ndo,
register const u_char *p, register const struct ip *ip,
register u_int length)
{
int dir;
u_int hlen;
dir = p[SLX_DIR];
ND_PRINT((ndo, dir == SLIPDIR_IN ? "I " : "O "));
if (ndo->ndo_nflag) {
/* XXX just dump the header */
register int i;
for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i)
ND_PRINT((ndo, "%02x.", p[i]));
ND_PRINT((ndo, "%02x: ", p[SLX_CHDR + CHDR_LEN - 1]));
return;
}
switch (p[SLX_CHDR] & 0xf0) {
case TYPE_IP:
ND_PRINT((ndo, "ip %d: ", length + SLIP_HDRLEN));
break;
case TYPE_UNCOMPRESSED_TCP:
/*
* The connection id is stored in the IP protocol field.
* Get it from the link layer since sl_uncompress_tcp()
* has restored the IP header copy to IPPROTO_TCP.
*/
lastconn = ((struct ip *)&p[SLX_CHDR])->ip_p;
hlen = IP_HL(ip);
hlen += TH_OFF((struct tcphdr *)&((int *)ip)[hlen]);
lastlen[dir][lastconn] = length - (hlen << 2);
ND_PRINT((ndo, "utcp %d: ", lastconn));
break;
default:
if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) {
compressed_sl_print(ndo, &p[SLX_CHDR], ip,
length, dir);
ND_PRINT((ndo, ": "));
} else
ND_PRINT((ndo, "slip-%d!: ", p[SLX_CHDR]));
}
}
static const u_char *
print_sl_change(netdissect_options *ndo,
const char *str, register const u_char *cp)
{
register u_int i;
if ((i = *cp++) == 0) {
i = EXTRACT_16BITS(cp);
cp += 2;
}
ND_PRINT((ndo, " %s%d", str, i));
return (cp);
}
static const u_char *
print_sl_winchange(netdissect_options *ndo,
register const u_char *cp)
{
register short i;
if ((i = *cp++) == 0) {
i = EXTRACT_16BITS(cp);
cp += 2;
}
if (i >= 0)
ND_PRINT((ndo, " W+%d", i));
else
ND_PRINT((ndo, " W%d", i));
return (cp);
}
static void
compressed_sl_print(netdissect_options *ndo,
const u_char *chdr, const struct ip *ip,
u_int length, int dir)
{
register const u_char *cp = chdr;
register u_int flags, hlen;
flags = *cp++;
if (flags & NEW_C) {
lastconn = *cp++;
ND_PRINT((ndo, "ctcp %d", lastconn));
} else
ND_PRINT((ndo, "ctcp *"));
/* skip tcp checksum */
cp += 2;
switch (flags & SPECIALS_MASK) {
case SPECIAL_I:
ND_PRINT((ndo, " *SA+%d", lastlen[dir][lastconn]));
break;
case SPECIAL_D:
ND_PRINT((ndo, " *S+%d", lastlen[dir][lastconn]));
break;
default:
if (flags & NEW_U)
cp = print_sl_change(ndo, "U=", cp);
if (flags & NEW_W)
cp = print_sl_winchange(ndo, cp);
if (flags & NEW_A)
cp = print_sl_change(ndo, "A+", cp);
if (flags & NEW_S)
cp = print_sl_change(ndo, "S+", cp);
break;
}
if (flags & NEW_I)
cp = print_sl_change(ndo, "I+", cp);
/*
* 'hlen' is the length of the uncompressed TCP/IP header (in words).
* 'cp - chdr' is the length of the compressed header.
* 'length - hlen' is the amount of data in the packet.
*/
hlen = IP_HL(ip);
hlen += TH_OFF((struct tcphdr *)&((int32_t *)ip)[hlen]);
lastlen[dir][lastconn] = length - (hlen << 2);
ND_PRINT((ndo, " %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr)));
}