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authorAlexei Starovoitov <ast@plumgrid.com>2015-05-27 15:30:39 -0700
committerDavid S. Miller <davem@davemloft.net>2015-05-30 17:51:13 -0700
commit37e82c2f974b72c9ab49c787ef7b5bb1aec12768 (patch)
tree9d998b6f8ae66f6e50c48fff7136c3b93a157021 /net/core
parente01ec2199ef22e2cabd7d6e68a192f3eb728029f (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>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/filter.c18
1 files changed, 18 insertions, 0 deletions
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);

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