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 <richardbgob...@gmail.com>
Reviewed-by: Willem de Bruijn <will...@google.com>
---
include/net/ipv6.h | 1 +
net/ipv6/ip6_offload.c | 51 +++++++++++++++++++++++++++++++++---------
2 files changed, 42 insertions(+), 10 deletions(-)
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 78d38dd88aba..217240efa182 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -26,6 +26,7 @@ struct ip_tunnel_info;
#define SIN6_LEN_RFC2133 24
#define IPV6_MAXPLEN 65535
+#define IPV6_MIN_EXTHDR_LEN 8
/*
* NextHeader field of IPv6 header
diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index 0e0b5fed0995..c07111d8f56a 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -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 + IPV6_MIN_EXTHDR_LEN, 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--;
--
2.36.1
