diff options
| author | Alexei Starovoitov <ast@plumgrid.com> | 2015-05-27 15:30:39 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-05-30 17:51:13 -0700 |
| commit | 37e82c2f974b72c9ab49c787ef7b5bb1aec12768 (patch) | |
| tree | 9d998b6f8ae66f6e50c48fff7136c3b93a157021 | |
| parent | e01ec2199ef22e2cabd7d6e68a192f3eb728029f (diff) | |
bpf: allow BPF programs access skb->skb_iif and skb->dev->ifindex fields
classic BPF already exposes skb->dev->ifindex via SKF_AD_IFINDEX extension.
Allow eBPF program to access it as well. Note that classic aborts execution
of the program if 'skb->dev == NULL' (which is inconvenient for program
writers), whereas eBPF returns zero in such case.
Also expose the 'skb_iif' field, since programs triggered by redirected
packet need to known the original interface index.
Summary:
__skb->ifindex -> skb->dev->ifindex
__skb->ingress_ifindex -> skb->skb_iif
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/uapi/linux/bpf.h | 2 | ||||
| -rw-r--r-- | net/core/filter.c | 18 |
2 files changed, 20 insertions, 0 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index f0a9af8b4dae..72f3080afa1e 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -236,6 +236,8 @@ struct __sk_buff { __u32 vlan_tci; __u32 vlan_proto; __u32 priority; + __u32 ingress_ifindex; + __u32 ifindex; }; #endif /* _UAPI__LINUX_BPF_H__ */ diff --git a/net/core/filter.c b/net/core/filter.c index 3adcca6f17a4..2c30d6632d66 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1499,6 +1499,24 @@ static u32 sk_filter_convert_ctx_access(int dst_reg, int src_reg, int ctx_off, offsetof(struct sk_buff, priority)); break; + case offsetof(struct __sk_buff, ingress_ifindex): + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, skb_iif) != 4); + + *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, + offsetof(struct sk_buff, skb_iif)); + break; + + case offsetof(struct __sk_buff, ifindex): + BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4); + + *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)), + dst_reg, src_reg, + offsetof(struct sk_buff, dev)); + *insn++ = BPF_JMP_IMM(BPF_JEQ, dst_reg, 0, 1); + *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, dst_reg, + offsetof(struct net_device, ifindex)); + break; + case offsetof(struct __sk_buff, mark): return convert_skb_access(SKF_AD_MARK, dst_reg, src_reg, insn); |