Commit dff0b016 authored by Richard Gobert's avatar Richard Gobert Committed by Jakub Kicinski
Browse files

net: gro: parse ipv6 ext headers without frag0 invalidation 



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: default avatarRichard Gobert <richardbgobert@gmail.com>
Reviewed-by: default avatarWillem de Bruijn <willemb@google.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/504130f6-b56c-4dcc-882c-97942c59f5b7@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent f2e3fc21

net/ipv6/ip6_offload.c

+41 −10
Original line number Diff line number Diff line
@@ -37,6 +37,40 @@ 
		INDIRECT_CALL_L4(cb, f2, f1, head, skb);	\

})



static int ipv6_gro_pull_exthdrs(struct sk_buff *skb, int off, int proto)

{

	const struct net_offload *ops = NULL;

	struct ipv6_opt_hdr *opth;



	for (;;) {

		int len;



		ops = rcu_dereference(inet6_offloads[proto]);



		if (unlikely(!ops))

			break;



		if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))

			break;



		opth = skb_gro_header(skb, off + sizeof(*opth), off);

		if (unlikely(!opth))

			break;



		len = ipv6_optlen(opth);



		opth = skb_gro_header(skb, off + len, off);

		if (unlikely(!opth))

			break;

		proto = opth->nexthdr;



		off += len;

	}



	skb_gro_pull(skb, off - skb_network_offset(skb));

	return proto;

}



static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)

{

	const struct net_offload *ops = NULL;
@@ -203,28 +237,25 @@ INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head, 
		goto out;



	skb_set_network_header(skb, off);

	skb_gro_pull(skb, sizeof(*iph));

	skb_set_transport_header(skb, skb_gro_offset(skb));



	flush += ntohs(iph->payload_len) != skb_gro_len(skb);

	flush += ntohs(iph->payload_len) != skb->len - hlen;



	proto = iph->nexthdr;

	ops = rcu_dereference(inet6_offloads[proto]);

	if (!ops || !ops->callbacks.gro_receive) {

		pskb_pull(skb, skb_gro_offset(skb));

		skb_gro_frag0_invalidate(skb);

		proto = ipv6_gso_pull_exthdrs(skb, proto);

		skb_gro_pull(skb, -skb_transport_offset(skb));

		skb_reset_transport_header(skb);

		__skb_push(skb, skb_gro_offset(skb));

		proto = ipv6_gro_pull_exthdrs(skb, hlen, proto);



		ops = rcu_dereference(inet6_offloads[proto]);

		if (!ops || !ops->callbacks.gro_receive)

			goto out;



		iph = ipv6_hdr(skb);

		iph = skb_gro_network_header(skb);

	} else {

		skb_gro_pull(skb, sizeof(*iph));

	}



	skb_set_transport_header(skb, skb_gro_offset(skb));



	NAPI_GRO_CB(skb)->proto = proto;



	flush--;