netfilter: nft_tproxy: restrict support to TCP and UDP transport protocols

[ Upstream commit 52f0f4e178c757b3d356087376aad8bd77271828 ]

Add unfront check for TCP and UDP packets before performing further
processing.

Fixes: 4ed8eb6570a4 ("netfilter: nf_tables: Add native tproxy support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
1 file changed