netlink: store set byteorder in NFTA_SET_USERDATA

The integer datatype has neither specific byteorder nor length. This
results in the following broken output:

 # nft list ruleset
 table ip x {
        chain y {
                mark set cpu map { 0 : 0x00000001, 16777216 : 0x00000002}
        }
 }

Currently, with BYTEORDER_INVALID, nft defaults on network byteorder,
hence the output above.

This patch stores the key byteorder in the userdata using a TLV
structure in the NFTA_SET_USERDATA area, so nft can interpret key
accordingly when dumping the set back to userspace.

Thus, after this patch the listing is correct:

 # nft list ruleset
 table ip x {
        chain y {
                mark set cpu map { 0 : 0x00000001, 1 : 0x00000002}
        }
 }

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/rule.h b/include/rule.h
index 878563d9..f5160daf 100644
--- a/include/rule.h
+++ b/include/rule.h
@@ -477,4 +477,10 @@ enum udata_type {
 
 #define UDATA_COMMENT_MAXLEN 128
 
+enum udata_set_type {
+	UDATA_SET_KEYBYTEORDER,
+	__UDATA_SET_MAX,
+};
+#define UDATA_SET_MAX (__UDATA_SET_MAX - 1)
+
 #endif /* NFTABLES_RULE_H */