From 3a07327d10a09379315c844c63f27941f5081e0a Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Tue, 25 Oct 2022 13:48:15 +0200 Subject: netfilter: nft_inner: support for inner tunnel header matching This new expression allows you to match on the inner headers that are encapsulated by any of the existing tunneling protocols. This expression parses the inner packet to set the link, network and transport offsets, so the existing expressions (with a few updates) can be reused to match on the inner headers. The inner expression supports for different tunnel combinations such as: - ethernet frame over IPv4/IPv6 packet, eg. VxLAN. - IPv4/IPv6 packet over IPv4/IPv6 packet, eg. IPIP. - IPv4/IPv6 packet over IPv4/IPv6 + transport header, eg. GRE. - transport header (ESP or SCTP) over transport header (usually UDP) The following fields are used to describe the tunnel protocol: - flags, which describe how to parse the inner headers: NFT_PAYLOAD_CTX_INNER_TUN, the tunnel provides its own header. NFT_PAYLOAD_CTX_INNER_ETHER, the ethernet frame is available as inner header. NFT_PAYLOAD_CTX_INNER_NH, the network header is available as inner header. NFT_PAYLOAD_CTX_INNER_TH, the transport header is available as inner header. For example, VxLAN sets on all of these flags. While GRE only sets on NFT_PAYLOAD_CTX_INNER_NH and NFT_PAYLOAD_CTX_INNER_TH. Then, ESP over UDP only sets on NFT_PAYLOAD_CTX_INNER_TH. The tunnel description is composed of the following attributes: - header size: in case the tunnel comes with its own header, eg. VxLAN. - type: this provides a hint to userspace on how to delinearize the rule. This is useful for VxLAN and Geneve since they run over UDP, since transport does not provide a hint. This is also useful in case hardware offload is ever supported. The type is not currently interpreted by the kernel. - expression: currently only payload supported. Follow up patch adds also inner meta support which is required by autogenerated dependencies. The exthdr expression should be supported too at some point. There is a new inner_ops operation that needs to be set on to allow to use an existing expression from the inner expression. This patch adds a new NFT_PAYLOAD_TUN_HEADER base which allows to match on the tunnel header fields, eg. vxlan vni. The payload expression is embedded into nft_inner private area and this private data area is passed to the payload inner eval function via direct call. Signed-off-by: Pablo Neira Ayuso --- net/netfilter/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/netfilter/Makefile') diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index 7a6b518ba2b4..1d4db1943936 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -86,7 +86,7 @@ nf_tables-objs := nf_tables_core.o nf_tables_api.o nft_chain_filter.o \ nf_tables_trace.o nft_immediate.o nft_cmp.o nft_range.o \ nft_bitwise.o nft_byteorder.o nft_payload.o nft_lookup.o \ nft_dynset.o nft_meta.o nft_rt.o nft_exthdr.o nft_last.o \ - nft_counter.o nft_objref.o \ + nft_counter.o nft_objref.o nft_inner.o \ nft_chain_route.o nf_tables_offload.o \ nft_set_hash.o nft_set_bitmap.o nft_set_rbtree.o \ nft_set_pipapo.o -- cgit v1.2.3