From: Alice Mikityanska Date: Thu, 11 Jun 2026 19:29:45 +0000 (+0200) Subject: net/sched: act_csum: don't mangle UDP tunnel GSO packets X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9bcb30b389ec5888590cb6ec58c7a3b80fe49a11;p=thirdparty%2Flinux.git net/sched: act_csum: don't mangle UDP tunnel GSO packets Similar to commit add641e7dee3 ("sched: act_csum: don't mangle TCP and UDP GSO packets"), UDP tunnel GSO packets going through act_csum shouldn't have their checksum calculated at this point, because it will be done after segmentation. Setting the checksum in act_csum modifies skb->ip_summed and prevents inner IP csum offload from kicking in, resulting in a packet with a bad checksum. Add UDP tunnel GSO packets to the exceptions, and also add UDP GSO (SKB_GSO_UDP_L4), as the same logic as in the commit mentioned above applies to UDP GSO too. Signed-off-by: Alice Mikityanska Reviewed-by: Davide Caratti Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20260611192955.604661-2-alice.kernel@fastmail.im Signed-off-by: Paolo Abeni --- diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c index a9e4635d899e..078d3a27130b 100644 --- a/net/sched/act_csum.c +++ b/net/sched/act_csum.c @@ -259,7 +259,9 @@ static int tcf_csum_ipv4_udp(struct sk_buff *skb, unsigned int ihl, const struct iphdr *iph; u16 ul; - if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP) + if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & + (SKB_GSO_UDP | SKB_GSO_UDP_L4 | + SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM)) return 1; /* @@ -315,7 +317,9 @@ static int tcf_csum_ipv6_udp(struct sk_buff *skb, unsigned int ihl, const struct ipv6hdr *ip6h; u16 ul; - if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP) + if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & + (SKB_GSO_UDP | SKB_GSO_UDP_L4 | + SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM)) return 1; /*