tcpdump/print-ipcomp.c
guy fcc82f451d The "__attribute__((packed))" tag on structures causes some files not to
compile with Sun C, as "interface.h" isn't being included before the
structures are being declared.

Furthermore, in the files that Sun C *can* compile, it doesn't cause Sun
C to generate code that's safe with unaligned accesses, as
"__attribute__" is defined as a do-nothing macro with compilers that
don't support it.

Therefore, we get rid of that tag on the structures to which it was
added, and instead use "EXTRACT_16BIT()" and "EXTRACT_32BIT()" to fetch
16-bit and 32-bit big-endian quantities from packets.  We also fix some
other references to multi-byte quantities to get rid of code that tries
to do unaligned loads on platforms that don't support them.

We also throw in a hack that makes those macros use
"__attribute__((packed))" on structures containing only one 16-bit or
32-bit integer to get the compiler to generate unaligned-safe code
rather than doing it by hand.  (GCC on SPARC produces the same code that
doing it by hand does; I don't know if GCC on any other big-endian
strict-alignment processor generates better code for that case.  On
little-endian processors, as "ntohs()" and "ntohl()" might be functions,
that might actually produce worse code.)

Fix some places to use "%u" rather than "%d" to print unsigned
quantities.
2002-12-11 07:13:49 +00:00

94 lines
2.6 KiB
C

/*
* Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994
* 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.
*/
#ifndef lint
static const char rcsid[] =
"@(#) $Header: /tcpdump/master/tcpdump/print-ipcomp.c,v 1.17 2002-12-11 07:14:03 guy Exp $";
#endif
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include <tcpdump-stdinc.h>
#include <stdio.h>
struct ipcomp {
u_int8_t comp_nxt; /* Next Header */
u_int8_t comp_flags; /* Length of data, in 32bit */
u_int16_t comp_cpi; /* Compression parameter index */
};
#if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
#include <zlib.h>
#endif
#include "interface.h"
#include "addrtoname.h"
#include "extract.h"
int
ipcomp_print(register const u_char *bp, int *nhdr)
{
register const struct ipcomp *ipcomp;
register const u_char *ep;
u_int16_t cpi;
#if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
int advance;
#endif
ipcomp = (struct ipcomp *)bp;
cpi = EXTRACT_16BITS(&ipcomp->comp_cpi);
/* 'ep' points to the end of available data. */
ep = snapend;
if ((u_char *)(ipcomp + 1) >= ep - sizeof(struct ipcomp)) {
fputs("[|IPCOMP]", stdout);
goto fail;
}
printf("IPComp(cpi=0x%04x)", cpi);
#if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
if (1)
goto fail;
/*
* We may want to decompress the packet here. Packet buffer
* management is a headache (if we decompress, packet will become
* larger).
*/
if (nhdr)
*nhdr = ipcomp->comp_nxt;
advance = sizeof(struct ipcomp);
printf(": ");
return advance;
#endif
fail:
if (nhdr)
*nhdr = -1;
return 65536;
}