On Wed, Jan 3, 2024 at 3:44 PM Richard Gobert richardbgobert@gmail.com wrote:
The existing code always pulls the IPv6 header and sets the transport offset initially. Then optionally again pulls any extension headers in ipv6_gso_pull_exthdrs and sets the transport offset again on return from that call. skb->data is set at the start of the first extension header before calling ipv6_gso_pull_exthdrs, and must disable the frag0 optimization because that function uses pskb_may_pull/pskb_pull instead of skb_gro_ helpers. It sets the GRO offset to the TCP header with skb_gro_pull and sets the transport header. Then returns skb->data to its position before this block.
This commit introduces a new helper function - ipv6_gro_pull_exthdrs - which is used in ipv6_gro_receive to pull ipv6 ext headers instead of ipv6_gso_pull_exthdrs. Thus, there is no modification of skb->data, all operations use skb_gro_* helpers, and the frag0 fast path can be taken for IPv6 packets with ext headers.
Signed-off-by: Richard Gobert richardbgobert@gmail.com Reviewed-by: Willem de Bruijn willemb@google.com Reviewed-by: David Ahern dsahern@kernel.org
Reviewed-by: Eric Dumazet edumazet@google.com
Thanks !