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.

1 files changed, 2 insertions, 2 deletions

diff --git a/tcp.h b/tcp.h
index 667948d9..43587ec4 100644
--- a/tcp.h
+++ b/tcp.h
@@ -1,4 +1,4 @@
-/* @(#) $Header: /tcpdump/master/tcpdump/tcp.h,v 1.9 2002-11-09 17:19:32 itojun Exp $ (LBL) */
+/* @(#) $Header: /tcpdump/master/tcpdump/tcp.h,v 1.10 2002-12-11 07:14:11 guy Exp $ (LBL) */
 /*
  * Copyright (c) 1982, 1986, 1993
  *	The Regents of the University of California.  All rights reserved.
@@ -58,7 +58,7 @@ struct tcphdr {
 	u_int16_t	th_win;			/* window */
 	u_int16_t	th_sum;			/* checksum */
 	u_int16_t	th_urp;			/* urgent pointer */
-} __attribute__((packed));
+};
 
 #define	TCPOPT_EOL		0
 #define	TCPOPT_NOP		1