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 <willemb@google.com>
Signed-off-by: Xuesen Huang <huangxuesen@kuaishou.com>
Signed-off-by: Zhiyong Cheng <chengzhiyong@kuaishou.com>
Signed-off-by: Li Wang <wangli09@kuaishou.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/bpf/20210304064046.6232-1-hxseverything@gmail.com
This commit is contained in:
Xuesen Huang 2021-03-04 14:40:46 +08:00 committed by Daniel Borkmann
parent bce8623135
commit d01b59c9ae
3 changed files with 20 additions and 1 deletions

View File

@ -2484,6 +2484,10 @@ union bpf_attr {
* Use with ENCAP_L3/L4 flags to further specify the tunnel
* type; *len* is the length of the inner MAC header.
*
* * **BPF_F_ADJ_ROOM_ENCAP_L2_ETH**:
* Use with BPF_F_ADJ_ROOM_ENCAP_L2 flag to further specify the
* L2 type as Ethernet.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
@ -4916,6 +4920,7 @@ enum {
BPF_F_ADJ_ROOM_ENCAP_L4_GRE = (1ULL << 3),
BPF_F_ADJ_ROOM_ENCAP_L4_UDP = (1ULL << 4),
BPF_F_ADJ_ROOM_NO_CSUM_RESET = (1ULL << 5),
BPF_F_ADJ_ROOM_ENCAP_L2_ETH = (1ULL << 6),
};
enum {

View File

@ -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);

View File

@ -2484,6 +2484,10 @@ union bpf_attr {
* Use with ENCAP_L3/L4 flags to further specify the tunnel
* type; *len* is the length of the inner MAC header.
*
* * **BPF_F_ADJ_ROOM_ENCAP_L2_ETH**:
* Use with BPF_F_ADJ_ROOM_ENCAP_L2 flag to further specify the
* L2 type as Ethernet.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
@ -4916,6 +4920,7 @@ enum {
BPF_F_ADJ_ROOM_ENCAP_L4_GRE = (1ULL << 3),
BPF_F_ADJ_ROOM_ENCAP_L4_UDP = (1ULL << 4),
BPF_F_ADJ_ROOM_NO_CSUM_RESET = (1ULL << 5),
BPF_F_ADJ_ROOM_ENCAP_L2_ETH = (1ULL << 6),
};
enum {