From: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
To: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@kernel.org>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Simon Horman <horms@kernel.org>,
Willem de Bruijn <willemb@google.com>,
Alexander Lobakin <alobakin@pm.me>
Cc: linux-kernel@vger.kernel.org,
Eva Kurchatova <eva.kurchatova@virtuozzo.com>,
netdev@vger.kernel.org
Subject: [PATCH] udp: let rx-udp-gro-forwarding aggregate under encapsulation
Date: Thu, 8 Oct 2026 19:38:16 +0300 [thread overview]
Message-ID: <20261008163817.2983484-1-eva.kurchatova@virtuozzo.com> (raw)
The rx-udp-gro-forwarding checks of the veth kselftest fail with "got
10 packets, expected 1" on a host where something uses UDP
encapsulation, a vxlan say, and pass on a host where nothing does.
Since commit f2e9de210d50 ("udp: gro behind static key") the receiving
socket is looked up only once a tunnel socket exists, and commit
36707061d6ba ("udp: allow forwarding of plain (non-fraglisted) UDP GRO
packets") takes "no socket found" for "forwarded" and aggregates only
then. So the device setting works on a host without a tunnel and stops
working with one.
Aggregate whenever the device asks, socket found or not. That is what
every host without a tunnel has done all along: a local socket without
UDP_GRO gets the packets resegmented on delivery, and a tunnel socket
keeps its own receive path.
Fixes: 36707061d6ba ("udp: allow forwarding of plain (non-fraglisted) UDP GRO packets")
Signed-off-by: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
---
net/ipv4/udp_offload.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index cf07c3c6611a..d4e0e6bb9959 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -804,7 +804,7 @@ struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
NAPI_GRO_CB(skb)->is_flist = sk ? !udp_test_bit(GRO_ENABLED, sk) : 1;
- if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
+ if ((skb->dev->features & NETIF_F_GRO_UDP_FWD) ||
(sk && udp_test_bit(GRO_ENABLED, sk)) || NAPI_GRO_CB(skb)->is_flist)
return call_gro_receive(udp_gro_receive_segment, head, skb);
--
2.56.0
reply other threads:[~2026-10-08 16:38 UTC|newest]
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