From 1814096980bbe546c4384b7b064126cbe7d40d30 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Thu, 24 Nov 2016 12:04:55 +0100 Subject: netfilter: nft_payload: layer 4 checksum adjustment for pseudoheader fields This patch adds a new flag that signals the kernel to update layer 4 checksum if the packet field belongs to the layer 4 pseudoheader. This implicitly provides stateless NAT 1:1 that is useful under very specific usecases. Since rules mangling layer 3 fields that are part of the pseudoheader may potentially convey any layer 4 packet, we have to deal with the layer 4 checksum adjustment using protocol specific code. This patch adds support for TCP, UDP and ICMPv6, since they include the pseudoheader in the layer 4 checksum calculation. ICMP doesn't, so we can skip it. Signed-off-by: Pablo Neira Ayuso --- include/uapi/linux/netfilter/nf_tables.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index 14e5f619167e..f030e59aa2ec 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -659,6 +659,10 @@ enum nft_payload_csum_types { NFT_PAYLOAD_CSUM_INET, }; +enum nft_payload_csum_flags { + NFT_PAYLOAD_L4CSUM_PSEUDOHDR = (1 << 0), +}; + /** * enum nft_payload_attributes - nf_tables payload expression netlink attributes * @@ -669,6 +673,7 @@ enum nft_payload_csum_types { * @NFTA_PAYLOAD_SREG: source register to load data from (NLA_U32: nft_registers) * @NFTA_PAYLOAD_CSUM_TYPE: checksum type (NLA_U32) * @NFTA_PAYLOAD_CSUM_OFFSET: checksum offset relative to base (NLA_U32) + * @NFTA_PAYLOAD_CSUM_FLAGS: checksum flags (NLA_U32) */ enum nft_payload_attributes { NFTA_PAYLOAD_UNSPEC, @@ -679,6 +684,7 @@ enum nft_payload_attributes { NFTA_PAYLOAD_SREG, NFTA_PAYLOAD_CSUM_TYPE, NFTA_PAYLOAD_CSUM_OFFSET, + NFTA_PAYLOAD_CSUM_FLAGS, __NFTA_PAYLOAD_MAX }; #define NFTA_PAYLOAD_MAX (__NFTA_PAYLOAD_MAX - 1) -- cgit v1.2.3