We use the openvswitch 2.7.0 and find the issue when ovs use the skb_get_hash() to get the hash of QinQ skb. Because the __skb_flow_dissect() get the wrong vlan protocol headers.
Someone report bonding driver has the same issue use the __skb_flow_dissect() to count hash in bond_xmit_hash: https://lore.kernel.org/netdev/00a5d09f-a23e-661f-60c0- 75fba6227...@huawei.com/T/. Because in netif_receive_skb, the skb_network_header points to vlan head, but in dev_hard_start_xmit, the skb_network_header points to IP header. So use the skb_network_offset to get the vlan head is not reliable. Should we use the skb_mac_offset instead the skb_network_offset to get the vlan head when proto is ETH_P_8021AD or ETH_P_8021Q? Signed-off-by: Feng tiantian <fengtiant...@huawei.com> --- net/core/flow_dissector.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 415b95f..9a77d5d 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -629,6 +629,13 @@ bool __skb_flow_dissect(const struct sk_buff *skb, skb->vlan_proto : skb->protocol; nhoff = skb_network_offset(skb); hlen = skb_headlen(skb); + + if (proto == htons(ETH_P_8021AD) || + proto == htons(ETH_P_8021Q)) { + if (skb_mac_header_was_set(skb)) + nhoff = skb_mac_offset(skb) + ETH_HLEN; + } + #if IS_ENABLED(CONFIG_NET_DSA) if (unlikely(skb->dev && netdev_uses_dsa(skb->dev))) { const struct dsa_device_ops *ops; -- 1.8.3.1
