[oe] [meta-networking][PATCH] ebtables: make it be able to work on 64bit kernel with 32 bit userspace

[Mark Hatle]

From: "Roy.Li" <rongqing.li at windriver.com>


[ This patch is being sent up for Yocto Project compliance.  I'm not sure it's generally applicable. ]


Some structs, which is used to communicate between user space and kernel,
have the alignment issue on 64bit kernel with 32 bit userspace. To fix
this issue, ebtables redefines these struct, not use the kernel(sysroot)
include/uapi/linux/netfilter_bridge/ebtables.h, like ebt_entry_target:

The kernel's:
struct ebt_entry_target {
        union {
                char name[EBT_FUNCTION_MAXNAMELEN];
                struct xt_target *target;
        } u;
        /* size of data */
        unsigned int target_size;
        unsigned char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
};

The ebtables:
struct ebt_entry_target
{
        union {
                char name[EBT_FUNCTION_MAXNAMELEN];
                struct ebt_target *target;
        } u;
        /* size of data */
        unsigned int target_size;
|#ifdef KERNEL_64_USERSPACE_32
        unsigned int pad;
|#endif
        unsigned char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
};

To make it work on 64bit kernel and 32bit userspace, KERNEL_64_USERSPACE_32
is needed to be enabled.

If the MLPREFIX of package matchs "lib.?32", the 32bit multilib  package on
64bit kernel is being built.

Signed-off-by: Roy.Li <rongqing.li at windriver.com>
Signed-off-by: Mark Hatle <mark.hatle at windriver.com>
---
 recipes-filter/ebtables/ebtables_2.0.10-4.bb | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/recipes-filter/ebtables/ebtables_2.0.10-4.bb b/recipes-filter/ebtables/ebtables_2.0.10-4.bb
index 32cfc75..ca084e3 100644
--- a/recipes-filter/ebtables/ebtables_2.0.10-4.bb
+++ b/recipes-filter/ebtables/ebtables_2.0.10-4.bb
@@ -27,6 +27,17 @@ S = "${WORKDIR}/ebtables-v${PV}"
 
 inherit update-rc.d systemd
 
+python __anonymous () {
+    import re
+
+    multilib = d.getVar('MLPREFIX', True)
+    if multilib:
+        searchstr = "lib.?32"
+        reg = re.compile(searchstr)
+        if reg.search(multilib):
+            d.appendVar('CFLAGS' ,' -DKERNEL_64_USERSPACE_32 -DEBT_MIN_ALIGN=8')
+}
+
 EXTRA_OEMAKE = " \
         BINDIR=${base_sbindir} \
         MANDIR=${mandir} \
-- 
1.9.3