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udp: properly complete L4 GRO over UDP tunnel packet

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After the previous patch, the stack can do L4 UDP aggregation
on top of a UDP tunnel.

In such scenario, udp{4,6}_gro_complete will be called twice. This function
will enter its is_flist branch immediately, even though that is only
correct on the second call, as GSO_FRAGLIST is only relevant for the
inner packet.

Instead, we need to try first UDP tunnel-based aggregation, if the GRO
packet requires that.

This patch changes udp{4,6}_gro_complete to skip the frag list processing
when while encap_mark == 1, identifying processing of the outer tunnel
header.
Additionally, clears the field in udp_gro_complete() so that we can enter
the frag list path on the next round, for the inner header.

v1 -> v2:
 - hopefully clarified the commit message

Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2021-03-30 12:28:51 +02:00 committed by David S. Miller
parent 18f25dc399
commit e0e3070a9b
2 changed files with 9 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

8
net/ipv4/udp_offload.c
View file

@ -642,6 +642,11 @@ int udp_gro_complete(struct sk_buff *skb, int nhoff,
skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
: SKB_GSO_UDP_TUNNEL; : SKB_GSO_UDP_TUNNEL;
/* clear the encap mark, so that inner frag_list gro_complete
* can take place
*/
NAPI_GRO_CB(skb)->encap_mark = 0;
/* Set encapsulation before calling into inner gro_complete() /* Set encapsulation before calling into inner gro_complete()
* functions to make them set up the inner offsets. * functions to make them set up the inner offsets.
*/ */
@ -665,7 +670,8 @@ INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
const struct iphdr *iph = ip_hdr(skb); const struct iphdr *iph = ip_hdr(skb);
struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
if (NAPI_GRO_CB(skb)->is_flist) { /* do fraglist only if there is no outer UDP encap (or we already processed it) */
if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) {
uh->len = htons(skb->len - nhoff); uh->len = htons(skb->len - nhoff);
skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4); skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);

3
net/ipv6/udp_offload.c
View file

@ -163,7 +163,8 @@ INDIRECT_CALLABLE_SCOPE int udp6_gro_complete(struct sk_buff *skb, int nhoff)
const struct ipv6hdr *ipv6h = ipv6_hdr(skb); const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
if (NAPI_GRO_CB(skb)->is_flist) { /* do fraglist only if there is no outer UDP encap (or we already processed it) */
if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) {
uh->len = htons(skb->len - nhoff); uh->len = htons(skb->len - nhoff);
skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4); skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);