netfilter: nf_tables: add support for inverted logic in nft_lookup
Introduce a new configuration option for this expression, which allows users
to invert the logic of set lookups.
In _init() we will now return EINVAL if NFT_LOOKUP_F_INV is in anyway
related to a map lookup.
The code in the _eval() function has been untangled and updated to sopport the
XOR of options, as we should consider 4 cases:
* lookup false, invert false -> NFT_BREAK
* lookup false, invert true -> return w/o NFT_BREAK
* lookup true, invert false -> return w/o NFT_BREAK
* lookup true, invert true -> NFT_BREAK
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 6a4dbe0..01751fa 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -546,6 +546,10 @@
};
#define NFTA_CMP_MAX (__NFTA_CMP_MAX - 1)
+enum nft_lookup_flags {
+ NFT_LOOKUP_F_INV = (1 << 0),
+};
+
/**
* enum nft_lookup_attributes - nf_tables set lookup expression netlink attributes
*
@@ -553,6 +557,7 @@
* @NFTA_LOOKUP_SREG: source register of the data to look for (NLA_U32: nft_registers)
* @NFTA_LOOKUP_DREG: destination register (NLA_U32: nft_registers)
* @NFTA_LOOKUP_SET_ID: uniquely identifies a set in a transaction (NLA_U32)
+ * @NFTA_LOOKUP_FLAGS: flags (NLA_U32: enum nft_lookup_flags)
*/
enum nft_lookup_attributes {
NFTA_LOOKUP_UNSPEC,
@@ -560,6 +565,7 @@
NFTA_LOOKUP_SREG,
NFTA_LOOKUP_DREG,
NFTA_LOOKUP_SET_ID,
+ NFTA_LOOKUP_FLAGS,
__NFTA_LOOKUP_MAX
};
#define NFTA_LOOKUP_MAX (__NFTA_LOOKUP_MAX - 1)