mirror of
https://github.com/the-tcpdump-group/tcpdump.git
synced 2024-11-28 04:25:16 +08:00
a11713da52
Finish converting over to having the caller print the IP address (except for UDP, TCP and SCTP). This consists mostly of removing places where the IP address is printed, both in the big "case" in ip_print() and in the individual printers. Also fix a couple of spacing bugs.
177 lines
4.3 KiB
C
177 lines
4.3 KiB
C
/*
|
|
* Copyright (c) 1996
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms are permitted
|
|
* provided that the above copyright notice and this paragraph are
|
|
* duplicated in all such forms and that any documentation,
|
|
* advertising materials, and other materials related to such
|
|
* distribution and use acknowledge that the software was developed
|
|
* by the University of California, Lawrence Berkeley Laboratory,
|
|
* Berkeley, CA. The name of the University may not 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 MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
|
|
*
|
|
* Initial contribution from John Hawkinson <jhawk@bbnplanet.com>
|
|
*
|
|
* This module implements support for decoding GRE (Generic Routing
|
|
* Encapsulation) tunnels; they're documented in RFC1701 and RFC1702.
|
|
* This code only supports the IP encapsulation thereof.
|
|
*/
|
|
|
|
#ifndef lint
|
|
static const char rcsid[] =
|
|
"@(#) $Header: /tcpdump/master/tcpdump/print-gre.c,v 1.13 2001-06-15 22:17:31 fenner Exp $";
|
|
#endif
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
#include "config.h"
|
|
#endif
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/time.h>
|
|
#include <sys/uio.h>
|
|
#include <sys/socket.h>
|
|
|
|
#include <netinet/in.h>
|
|
|
|
#include <netdb.h>
|
|
#include <stdio.h>
|
|
|
|
#include "interface.h"
|
|
#include "addrtoname.h"
|
|
#include "extract.h" /* must come after interface.h */
|
|
|
|
struct gre {
|
|
u_int16_t flags;
|
|
u_int16_t proto;
|
|
};
|
|
|
|
/* RFC 2784 - GRE */
|
|
#define GRE_CP 0x8000 /* Checksum Present */
|
|
#define GRE_VER_MASK 0x0007 /* Version */
|
|
|
|
/* RFC 2890 - Key and Sequence extensions to GRE */
|
|
#define GRE_KP 0x2000 /* Key Present */
|
|
#define GRE_SP 0x1000 /* Sequence Present */
|
|
|
|
/* Legacy from RFC 1700 */
|
|
#define GRE_RP 0x4000 /* Routing Present */
|
|
#define GRE_sP 0x0800 /* strict source route present */
|
|
#define GRE_RECUR_MASK 0x0700 /* Recursion Control */
|
|
#define GRE_RECUR_SHIFT 8
|
|
|
|
#define GRE_COP (GRE_RP|GRE_CP) /* Checksum & Offset Present */
|
|
|
|
/* "Enhanced GRE" from RFC2637 - PPTP */
|
|
#define GRE_AP 0x0080 /* Ack present */
|
|
|
|
#define GRE_MBZ_MASK 0x0078 /* not defined */
|
|
|
|
/*
|
|
* Deencapsulate and print a GRE-tunneled IP datagram
|
|
*/
|
|
void
|
|
gre_print(const u_char *bp, u_int length)
|
|
{
|
|
const u_char *cp = bp + 4;
|
|
const struct gre *gre;
|
|
u_int16_t flags, proto;
|
|
u_short ver=0;
|
|
u_short extracted_ethertype;
|
|
|
|
gre = (const struct gre *)bp;
|
|
|
|
TCHECK(gre->proto);
|
|
flags = EXTRACT_16BITS(&gre->flags);
|
|
proto = EXTRACT_16BITS(&gre->proto);
|
|
(void)printf("gre ");
|
|
|
|
if (flags) {
|
|
/* Decode the flags */
|
|
putchar('[');
|
|
if (flags & GRE_CP)
|
|
putchar('C');
|
|
if (flags & GRE_RP)
|
|
putchar('R');
|
|
if (flags & GRE_KP)
|
|
putchar('K');
|
|
if (flags & GRE_SP)
|
|
putchar('S');
|
|
if (flags & GRE_sP)
|
|
putchar('s');
|
|
if (flags & GRE_AP)
|
|
putchar('A');
|
|
if (flags & GRE_RECUR_MASK)
|
|
printf("R%x", (flags & GRE_RECUR_MASK) >> GRE_RECUR_SHIFT);
|
|
ver = flags & GRE_VER_MASK;
|
|
printf("v%u", ver);
|
|
|
|
if (flags & GRE_MBZ_MASK)
|
|
printf("!%x", flags & GRE_MBZ_MASK);
|
|
fputs("] ", stdout);
|
|
}
|
|
|
|
if (flags & GRE_COP) {
|
|
int checksum, offset;
|
|
|
|
TCHECK2(*cp, 4);
|
|
checksum = EXTRACT_16BITS(cp);
|
|
offset = EXTRACT_16BITS(cp + 2);
|
|
|
|
if (flags & GRE_CP) {
|
|
/* Checksum present */
|
|
|
|
/* todo: check checksum */
|
|
if (vflag > 1)
|
|
printf("C:%04x ", checksum);
|
|
}
|
|
if (flags & GRE_RP) {
|
|
/* Offset present */
|
|
|
|
if (vflag > 1)
|
|
printf("O:%04x ", offset);
|
|
}
|
|
cp += 4; /* skip checksum and offset */
|
|
}
|
|
if (flags & GRE_KP) {
|
|
TCHECK2(*cp, 4);
|
|
if (ver == 1) { /* PPTP */
|
|
if (vflag > 1)
|
|
printf("PL:%u ", EXTRACT_16BITS(cp));
|
|
printf("ID:%04x ", EXTRACT_16BITS(cp+2));
|
|
}
|
|
else
|
|
printf("K:%08x ", EXTRACT_32BITS(cp));
|
|
cp += 4; /* skip key */
|
|
}
|
|
if (flags & GRE_SP) {
|
|
TCHECK2(*cp, 4);
|
|
printf("S:%u ", EXTRACT_32BITS(cp));
|
|
cp += 4; /* skip seq */
|
|
}
|
|
if (flags & GRE_AP && ver >= 1) {
|
|
TCHECK2(*cp, 4);
|
|
printf("A:%u ", EXTRACT_32BITS(cp));
|
|
cp += 4; /* skip ack */
|
|
}
|
|
/* We don't support routing fields (variable length) now. Punt. */
|
|
if (flags & GRE_RP)
|
|
return;
|
|
|
|
TCHECK(cp[0]);
|
|
|
|
length -= cp - bp;
|
|
if (ether_encap_print(proto, cp, length, length,
|
|
&extracted_ethertype) == 0)
|
|
printf("gre-proto-0x%04X", proto);
|
|
return;
|
|
|
|
trunc:
|
|
fputs("[|gre]", stdout);
|
|
|
|
}
|