On Mon, Feb 8, 2021 at 7:16 AM huangxuesen <hxseveryth...@gmail.com> wrote: > > From: huangxuesen <huangxue...@kuaishou.com> > > When pushing vxlan tunnel header, set inner protocol as ETH_P_TEB in skb > to avoid HW device disabling udp tunnel segmentation offload, just like > vxlan_build_skb does. > > Drivers for NIC may invoke vxlan_features_check to check the > inner_protocol in skb for vxlan packets to decide whether to disable > NETIF_F_GSO_MASK. Currently it sets inner_protocol as the original > skb->protocol, that will make mlx5_core disable TSO and lead to huge > performance degradation. > > Signed-off-by: huangxuesen <huangxue...@kuaishou.com> > Signed-off-by: chengzhiyong <chengzhiy...@kuaishou.com> > Signed-off-by: wangli <wangl...@kuaishou.com> > --- > net/core/filter.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/net/core/filter.c b/net/core/filter.c > index 255aeee72402..f8d3ba3fe10f 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -3466,7 +3466,12 @@ static int bpf_skb_net_grow(struct sk_buff *skb, u32 > off, u32 len_diff, > skb->inner_mac_header = inner_net - inner_mac_len; > skb->inner_network_header = inner_net; > skb->inner_transport_header = inner_trans; > - skb_set_inner_protocol(skb, skb->protocol); > + > + if (flags & BPF_F_ADJ_ROOM_ENCAP_L4_UDP && > + inner_mac_len == ETH_HLEN) > + skb_set_inner_protocol(skb, htons(ETH_P_TEB));
This may be used by vxlan, but it does not imply it. Adding ETH_HLEN bytes likely means pushing an Ethernet header, but same point. Conversely, pushing an Ethernet header is not limited to UDP encap. This probably needs a new explicit BPF_F_ADJ_ROOM_.. flag, rather than trying to infer from imprecise heuristics.
