From: Alexander Lobakin alobakin@pm.me
[ Upstream commit 8be33ecfc1ffd2da20cc29e957e4cb6eb99310cb ]
Similar to commit fda55eca5a33f ("net: introduce skb_transport_header_was_set()"), avoid resetting transport offsets that were already set by GRO layer. This not only mirrors the behavior of __netif_receive_skb_core(), but also makes sense when it comes to UDP GSO fraglists forwarding: transport offset of such skbs is set only once by GRO receive callback and remains untouched and correct up to the xmitting driver in 1:1 case, but becomes junk after untagging in ingress VLAN case and breaks UDP GSO offload. This does not happen after this change, and all types of forwarding of UDP GSO fraglists work as expected.
Since v1 [1]: - keep the code 1:1 with __netif_receive_skb_core() (Jakub).
[1] https://lore.kernel.org/netdev/zYurwsZRN7BkqSoikWQLVqHyxz18h4LhHU4NFa2Vw@cp4...
Signed-off-by: Alexander Lobakin alobakin@pm.me Link: https://lore.kernel.org/r/7JgIkgEztzt0W6ZtC9V9Cnk5qfkrUFYcpN871syCi8@cp4-web... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/skbuff.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index a4c4234976862..f38ed5b9f5bf7 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -4607,7 +4607,8 @@ struct sk_buff *skb_vlan_untag(struct sk_buff *skb) goto err_free;
skb_reset_network_header(skb); - skb_reset_transport_header(skb); + if (!skb_transport_header_was_set(skb)) + skb_reset_transport_header(skb); skb_reset_mac_len(skb);
return skb;