6578171a7f
This patch adds a minimal helper for doing the groundwork of changing the skb->protocol in a controlled way. Currently supported is v4 to v6 and vice versa transitions, which allows f.e. for a minimal, static nat64 implementation where applications in containers that still require IPv4 can be transparently operated in an IPv6-only environment. For example, host facing veth of the container can transparently do the transitions in a programmatic way with the help of clsact qdisc and cls_bpf. Idea is to separate concerns for keeping complexity of the helper lower, which means that the programs utilize bpf_skb_change_proto(), bpf_skb_store_bytes() and bpf_lX_csum_replace() to get the job done, instead of doing everything in a single helper (and thus partially duplicating helper functionality). Also, bpf_skb_change_proto() shouldn't need to deal with raw packet data as this is done by other helpers. bpf_skb_proto_6_to_4() and bpf_skb_proto_4_to_6() unclone the skb to operate on a private one, push or pop additionally required header space and migrate the gso/gro meta data from the shared info. We do mark the gso type as dodgy so that headers are checked and segs recalculated by the gso/gro engine. The gso_size target is adapted as well. The flags argument added is currently reserved and can be used for future extensions. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| .. | ||
| asm-generic | ||
| drm | ||
| linux | ||
| misc | ||
| mtd | ||
| rdma | ||
| scsi | ||
| sound | ||
| video | ||
| xen | ||
| Kbuild | ||