From d01b59c9ae94560fbcceaafeef39784d72765033 Mon Sep 17 00:00:00 2001 From: Xuesen Huang Date: Thu, 4 Mar 2021 14:40:46 +0800 Subject: bpf: Add bpf_skb_adjust_room flag BPF_F_ADJ_ROOM_ENCAP_L2_ETH bpf_skb_adjust_room sets the inner_protocol as skb->protocol for packets encapsulation. But that is not appropriate when pushing Ethernet header. Add an option to further specify encap L2 type and set the inner_protocol as ETH_P_TEB. Suggested-by: Willem de Bruijn Signed-off-by: Xuesen Huang Signed-off-by: Zhiyong Cheng Signed-off-by: Li Wang Signed-off-by: Daniel Borkmann Acked-by: Willem de Bruijn Link: https://lore.kernel.org/bpf/20210304064046.6232-1-hxseverything@gmail.com --- net/core/filter.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'net') diff --git a/net/core/filter.c b/net/core/filter.c index a526db494c62..588b19ba0da8 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3409,6 +3409,7 @@ static u32 bpf_skb_net_base_len(const struct sk_buff *skb) BPF_F_ADJ_ROOM_ENCAP_L3_MASK | \ BPF_F_ADJ_ROOM_ENCAP_L4_GRE | \ BPF_F_ADJ_ROOM_ENCAP_L4_UDP | \ + BPF_F_ADJ_ROOM_ENCAP_L2_ETH | \ BPF_F_ADJ_ROOM_ENCAP_L2( \ BPF_ADJ_ROOM_ENCAP_L2_MASK)) @@ -3445,6 +3446,10 @@ static int bpf_skb_net_grow(struct sk_buff *skb, u32 off, u32 len_diff, flags & BPF_F_ADJ_ROOM_ENCAP_L4_UDP) return -EINVAL; + if (flags & BPF_F_ADJ_ROOM_ENCAP_L2_ETH && + inner_mac_len < ETH_HLEN) + return -EINVAL; + if (skb->encapsulation) return -EALREADY; @@ -3463,7 +3468,11 @@ 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_L2_ETH) + skb_set_inner_protocol(skb, htons(ETH_P_TEB)); + else + skb_set_inner_protocol(skb, skb->protocol); skb->encapsulation = 1; skb_set_network_header(skb, mac_len); -- cgit v1.2.3