[PATCH] x_tables: fix alignment on [at least] ppc32 (was Re: 2.6.16-rc1: iptables broken on ppc32?)
Harald Welte
laforge at netfilter.org
Fri Jan 20 11:45:12 EST 2006
Hi,
the patch below fixes the problem on ppc32. Dave: Please apply.
[NETFILTER] x_tables: Fix XT_ALIGN() macro on [at least] ppc32
To keep backwards compatibility with old iptables userspace programs,
the new XT_ALIGN macro always has to return the same value as IPT_ALIGN,
IP6T_ALIGN or ARPT_ALIGN in previous kernels.
However, in those kernels the macro was defined in dependency to the
respective layer3 specifi data structures, which we can no longer do with
x_tables.
The fix is an ugly kludge, but it has been tested to solve the problem. Yet
another reason to move away from the current {ip,ip6,arp,eb}tables like
data structures.
Signed-off-by: Harald Welte <laforge at netfilter.org>
---
commit 470faeb379560fe877b685ca69be6a7e4f0e91ed
tree 5732ecd9bcab28469805752514e5c57ba26189a1
parent 44718bbfa186d58477163418d37df173aa2dd079
author Harald Welte <laforge at netfilter.org> Fri, 20 Jan 2006 01:44:24 +0100
committer Harald Welte <laforge at netfilter.org> Fri, 20 Jan 2006 01:44:24 +0100
include/linux/netfilter/x_tables.h | 15 ++++++++++++++-
1 files changed, 14 insertions(+), 1 deletions(-)
diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index 472f048..65f9cd8 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -19,7 +19,20 @@ struct xt_get_revision
/* For standard target */
#define XT_RETURN (-NF_REPEAT - 1)
-#define XT_ALIGN(s) (((s) + (__alignof__(void *)-1)) & ~(__alignof__(void *)-1))
+/* this is a dummy structure to find out the alignment requirement for a struct
+ * containing all the fundamental data types that are used in ipt_entry, ip6t_entry
+ * and arpt_entry. This sucks, and it is a hack. It will be my personal pleasure
+ * to remove it -HW */
+struct _xt_align
+{
+ u_int8_t u8;
+ u_int16_t u16;
+ u_int32_t u32;
+ u_int64_t u64;
+};
+
+#define XT_ALIGN(s) (((s) + (__alignof__(struct _xt_align)-1)) \
+ & ~(__alignof__(struct _xt_align)-1))
/* Standard return verdict, or do jump. */
#define XT_STANDARD_TARGET ""
--
- Harald Welte <laforge at netfilter.org> http://netfilter.org/
============================================================================
"Fragmentation is like classful addressing -- an interesting early
architectural error that shows how much experimentation was going
on while IP was being designed." -- Paul Vixie
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