From a0ca153f98db8cf25298565a09e11fe9d82846ad Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Tue, 5 Apr 2016 09:13:39 -0700 Subject: GRE: Disable segmentation offloads w/ CSUM and we are encapsulated via FOU This patch fixes an issue I found in which we were dropping frames if we had enabled checksums on GRE headers that were encapsulated by either FOU or GUE. Without this patch I was barely able to get 1 Gb/s of throughput. With this patch applied I am now at least getting around 6 Gb/s. The issue is due to the fact that with FOU or GUE applied we do not provide a transport offset pointing to the GRE header, nor do we offload it in software as the GRE header is completely skipped by GSO and treated like a VXLAN or GENEVE type header. As such we need to prevent the stack from generating it and also prevent GRE from generating it via any interface we create. Fixes: c3483384ee511 ("gro: Allow tunnel stacking in the case of FOU/GUE") Signed-off-by: Alexander Duyck Signed-off-by: David S. Miller --- net/ipv4/gre_offload.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'net/ipv4/gre_offload.c') diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c index c47539d04b88..6a5bd4317866 100644 --- a/net/ipv4/gre_offload.c +++ b/net/ipv4/gre_offload.c @@ -150,6 +150,14 @@ static struct sk_buff **gre_gro_receive(struct sk_buff **head, if ((greh->flags & ~(GRE_KEY|GRE_CSUM)) != 0) goto out; + /* We can only support GRE_CSUM if we can track the location of + * the GRE header. In the case of FOU/GUE we cannot because the + * outer UDP header displaces the GRE header leaving us in a state + * of limbo. + */ + if ((greh->flags & GRE_CSUM) && NAPI_GRO_CB(skb)->is_fou) + goto out; + type = greh->protocol; rcu_read_lock(); -- cgit v1.2.3