net: filter: add vlan tag access
BPF filters lack ability to access skb->vlan_tci
This patch adds two new ancillary accessors :
SKF_AD_VLAN_TAG (44) mapped to vlan_tx_tag_get(skb)
SKF_AD_VLAN_TAG_PRESENT (48) mapped to vlan_tx_tag_present(skb)
This allows libpcap/tcpdump to use a kernel filter instead of
having to fallback to accept all packets, then filter them in
user space.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Ani Sinha <ani@aristanetworks.com>
Suggested-by: Daniel Borkmann <danborkmann@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 24d251f..c9f0005 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -123,6 +123,8 @@
BPF_S_ANC_CPU,
BPF_S_ANC_ALU_XOR_X,
BPF_S_ANC_SECCOMP_LD_W,
+ BPF_S_ANC_VLAN_TAG,
+ BPF_S_ANC_VLAN_TAG_PRESENT,
};
#endif /* __LINUX_FILTER_H__ */
diff --git a/include/uapi/linux/filter.h b/include/uapi/linux/filter.h
index 3d79224..9cfde69 100644
--- a/include/uapi/linux/filter.h
+++ b/include/uapi/linux/filter.h
@@ -127,7 +127,9 @@
#define SKF_AD_RXHASH 32
#define SKF_AD_CPU 36
#define SKF_AD_ALU_XOR_X 40
-#define SKF_AD_MAX 44
+#define SKF_AD_VLAN_TAG 44
+#define SKF_AD_VLAN_TAG_PRESENT 48
+#define SKF_AD_MAX 52
#define SKF_NET_OFF (-0x100000)
#define SKF_LL_OFF (-0x200000)