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, 8 insertions, 7 deletions

diff --git a/print-frag6.c b/print-frag6.c
index 4e5309e1..c3cbe2f5 100644
--- a/print-frag6.c
+++ b/print-frag6.c
@@ -21,7 +21,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-frag6.c,v 1.14 2002-08-01 08:53:07 risso Exp $";
+    "@(#) $Header: /tcpdump/master/tcpdump/print-frag6.c,v 1.15 2002-12-11 07:14:00 guy Exp $";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -38,6 +38,7 @@ static const char rcsid[] =
 
 #include "interface.h"
 #include "addrtoname.h"
+#include "extract.h"
 
 int
 frag6_print(register const u_char *bp, register const u_char *bp2)
@@ -56,20 +57,20 @@ frag6_print(register const u_char *bp, register const u_char *bp2)
 
 	if (vflag) {
 		printf("frag (0x%08x:%d|%ld)",
-		       (u_int32_t)ntohl(dp->ip6f_ident),
-		       ntohs(dp->ip6f_offlg & IP6F_OFF_MASK),
-		       sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) -
+		       EXTRACT_32BITS(&dp->ip6f_ident),
+		       EXTRACT_16BITS(&dp->ip6f_offlg & IP6F_OFF_MASK),
+		       sizeof(struct ip6_hdr) + EXTRACT_16BITS(&ip6->ip6_plen) -
 			       (long)(bp - bp2) - sizeof(struct ip6_frag));
 	} else {
 		printf("frag (%d|%ld)",
-		       ntohs(dp->ip6f_offlg & IP6F_OFF_MASK),
-		       sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) -
+		       EXTRACT_16BITS(&dp->ip6f_offlg & IP6F_OFF_MASK),
+		       sizeof(struct ip6_hdr) + EXTRACT_16BITS(&ip6->ip6_plen) -
 			       (long)(bp - bp2) - sizeof(struct ip6_frag));
 	}
 
 #if 1
 	/* it is meaningless to decode non-first fragment */
-	if (ntohs(dp->ip6f_offlg & IP6F_OFF_MASK) != 0)
+	if (EXTRACT_16BITS(&dp->ip6f_offlg & IP6F_OFF_MASK) != 0)
 		return 65535;
 	else
 #endif