Subject: [PATCH] Socket filter ancilliary data access for skb->dev->type

From: Paul LeoNerd Evans <[email-masked]>
Date: Thu, 22 Apr 2010 13:12:53 +0100

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.

Signed-off-by: Paul Evans <[email-masked]>

---

diff -ur linux-2.6.33.2.orig/include/linux/filter.h linux-2.6.33.2/include/linux/filter.h
--- linux-2.6.33.2.orig/include/linux/filter.h	2010-04-02 00:02:33.000000000 +0100
+++ linux-2.6.33.2/include/linux/filter.h	2010-04-20 22:40:25.000000000 +0100
@@ -123,7 +123,8 @@
 #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)
 
diff -ur linux-2.6.33.2.orig/net/core/filter.c linux-2.6.33.2/net/core/filter.c
--- linux-2.6.33.2.orig/net/core/filter.c	2010-04-02 00:02:33.000000000 +0100
+++ linux-2.6.33.2/net/core/filter.c	2010-04-20 22:41:01.000000000 +0100
@@ -309,6 +309,9 @@
 		case SKF_AD_QUEUE:
 			A = skb->queue_mapping;
 			continue;
+		case SKF_AD_HATYPE:
+			A = skb->dev->type;
+			continue;
 		case SKF_AD_NLATTR: {
 			struct nlattr *nla;