tcpdump/lane.h
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

42 lines
1.1 KiB
C

/*
* Marko Kiiskila carnil@cs.tut.fi
*
* Tampere University of Technology - Telecommunications Laboratory
*
* Permission to use, copy, modify and distribute this
* software and its documentation is hereby granted,
* provided that both the copyright notice and this
* permission notice appear in all copies of the software,
* derivative works or modified versions, and any portions
* thereof, that both notices appear in supporting
* documentation, and that the use of this software is
* acknowledged in any publications resulting from using
* the software.
*
* TUT ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION AND DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS
* SOFTWARE.
*
*/
/* $Id: lane.h,v 1.7 2002-12-11 07:13:54 guy Exp $ */
#ifndef ETHER_ADDR_LEN
#define ETHER_ADDR_LEN 6
#endif
struct lecdatahdr_8023 {
u_int16_t le_header;
u_int8_t h_dest[ETHER_ADDR_LEN];
u_int8_t h_source[ETHER_ADDR_LEN];
u_int16_t h_type;
};
struct lane_controlhdr {
u_int16_t lec_header;
u_int8_t lec_proto;
u_int8_t lec_vers;
u_int16_t lec_opcode;
};