When using an 802.1ad bridge with vlan_tunnel, the C-VLAN tag is incorrectly stripped from frames during egress processing. br_handle_egress_vlan_tunnel() uses skb_vlan_pop() to remove the S-VLAN from hwaccel before VXLAN encapsulation. However, skb_vlan_pop() also moves any "next" VLAN from the payload into hwaccel: /* move next vlan tag to hw accel tag */ __skb_vlan_pop(skb, &vlan_tci); __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci); For QinQ frames where the C-VLAN sits in the payload, this moves it to hwaccel where it gets lost during VXLAN encapsulation. Fix by calling __vlan_hwaccel_clear_tag() directly, which clears only the hwaccel S-VLAN and leaves the payload untouched. This path is only taken when vlan_tunnel is enabled and tunnel_info is configured, so 802.1Q bridges are unaffected. Tested with 802.1ad bridge + VXLAN vlan_tunnel, verified C-VLAN preserved in VXLAN payload via tcpdump. Fixes: 11538d039ac6 ("bridge: vlan dst_metadata hooks in ingress and egress paths") Signed-off-by: Alexandre Knecht --- net/bridge/br_vlan_tunnel.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/net/bridge/br_vlan_tunnel.c b/net/bridge/br_vlan_tunnel.c index 12de0d1df0bc..a1b62507e521 100644 --- a/net/bridge/br_vlan_tunnel.c +++ b/net/bridge/br_vlan_tunnel.c @@ -189,7 +189,6 @@ int br_handle_egress_vlan_tunnel(struct sk_buff *skb, IP_TUNNEL_DECLARE_FLAGS(flags) = { }; struct metadata_dst *tunnel_dst; __be64 tunnel_id; - int err; if (!vlan) return 0; @@ -199,9 +198,13 @@ int br_handle_egress_vlan_tunnel(struct sk_buff *skb, return 0; skb_dst_drop(skb); - err = skb_vlan_pop(skb); - if (err) - return err; + /* For 802.1ad (QinQ), skb_vlan_pop() incorrectly moves the C-VLAN + * from payload to hwaccel after clearing S-VLAN. We only need to + * clear the hwaccel S-VLAN; the C-VLAN must stay in payload for + * correct VXLAN encapsulation. This is also correct for 802.1Q + * where no C-VLAN exists in payload. + */ + __vlan_hwaccel_clear_tag(skb); if (BR_INPUT_SKB_CB(skb)->backup_nhid) { __set_bit(IP_TUNNEL_KEY_BIT, flags); -- 2.43.0