net: Socket filter ancilliary data access for skb->dev->type

Add an SKF_AD_HATYPE field to the packet ancilliary data area, giving
access to skb->dev->type, as reported in the sll_hatype field.

When capturing packets on a PF_PACKET/SOCK_RAW socket bound to all
interfaces, there doesn't appear to be a way for the filter program to
actually find out the underlying hardware type the packet was captured
on. This patch adds such ability.

This patch also handles the case where skb->dev can be NULL, such as on
netlink sockets.

Signed-off-by: Paul Evans <leonerd@leonerd.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 29a0e3db9f43..151f5d703b7e 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -123,7 +123,8 @@ struct sock_fprog {	/* Required for SO_ATTACH_FILTER. */
 #define SKF_AD_NLATTR_NEST      16
 #define SKF_AD_MARK     20
 #define SKF_AD_QUEUE    24
-#define SKF_AD_MAX      28
+#define SKF_AD_HATYPE   28
+#define SKF_AD_MAX      32
 #define SKF_NET_OFF   (-0x100000)
 #define SKF_LL_OFF    (-0x200000)