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>
This commit is contained in:
Eric Dumazet 2012-10-27 02:26:17 +00:00 committed by David S. Miller
parent 0f6ae8f14e
commit f3335031b9
3 changed files with 14 additions and 1 deletions

View file

@ -127,7 +127,9 @@ struct sock_fprog { /* Required for SO_ATTACH_FILTER. */
#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)