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GRE: Disable segmentation offloads w/ CSUM and we are encapsulated via FOU

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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: c3483384ee ("gro: Allow tunnel stacking in the case of FOU/GUE")
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexander Duyck 2016-04-05 09:13:39 -07:00 • committed by David S. Miller
parent 0a1a37b6d6
commit a0ca153f98
5 changed files with 29 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

6
net/ipv4/fou.c
View file

@ -203,6 +203,9 @@ static struct sk_buff **fou_gro_receive(struct sk_buff **head,
*/
NAPI_GRO_CB(skb)->encap_mark = 0;
/* Flag this frame as already having an outer encap header */
NAPI_GRO_CB(skb)->is_fou = 1;
rcu_read_lock();
offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
ops = rcu_dereference(offloads[proto]);
@ -368,6 +371,9 @@ static struct sk_buff **gue_gro_receive(struct sk_buff **head,
*/
NAPI_GRO_CB(skb)->encap_mark = 0;
/* Flag this frame as already having an outer encap header */
NAPI_GRO_CB(skb)->is_fou = 1;
rcu_read_lock();
offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
ops = rcu_dereference(offloads[guehdr->proto_ctype]);

8
net/ipv4/gre_offload.c
View file

@ -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();

13
net/ipv4/ip_gre.c
View file

@ -862,9 +862,16 @@ static void __gre_tunnel_init(struct net_device *dev)
dev->hw_features |= GRE_FEATURES;
if (!(tunnel->parms.o_flags & TUNNEL_SEQ)) {
/* TCP offload with GRE SEQ is not supported. */
dev->features |= NETIF_F_GSO_SOFTWARE;
dev->hw_features |= NETIF_F_GSO_SOFTWARE;
/* TCP offload with GRE SEQ is not supported, nor
* can we support 2 levels of outer headers requiring
* an update.
*/
if (!(tunnel->parms.o_flags & TUNNEL_CSUM) ||
(tunnel->encap.type == TUNNEL_ENCAP_NONE)) {
dev->features |= NETIF_F_GSO_SOFTWARE;
dev->hw_features |= NETIF_F_GSO_SOFTWARE;
}
/* Can use a lockless transmit, unless we generate
* output sequences
*/