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

PATCH In review Paul LeoNerd Evans 2 participants 2 messages Apr 22, 2010

Subsystems (5)
Networking Network drivers BPF BPF core +1 more subsystems
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Paul LeoNerd Evans

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#0 lore raw

PATCH v2 1/1 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 <[email protected]>

---

include/linux/filter.h +2 -1
diff -ur linux-2.6.33.2.orig/include/linux/filter.h linux-2.6.33.2/include/linux/filter.h
@@ -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)
net/core/filter.c +7 -0
diff -ur linux-2.6.33.2.orig/net/core/filter.c linux-2.6.33.2/net/core/filter.c
@@ -301,6 +301,8 @@
 			A = skb->pkt_type;
 			continue;
 		case SKF_AD_IFINDEX:
+			if (!skb->dev)
+				return 0;
 			A = skb->dev->ifindex;
 			continue;
 		case SKF_AD_MARK:

@@ -309,6 +311,11 @@
 		case SKF_AD_QUEUE:
 			A = skb->queue_mapping;
 			continue;
+		case SKF_AD_HATYPE:
+			if (!skb->dev)
+				return 0;
+			A = skb->dev->type;
+			continue;
 		case SKF_AD_NLATTR: {
 			struct nlattr *nla;
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#1 lore raw

From: Paul LeoNerd Evans <[email protected]>
Date: Thu, 22 Apr 2010 14:32:22 +0100

Quoted 8 lines

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.

Quoted 4 lines

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

Signed-off-by Paul Evans <[email protected]>

Looks good, applied to net-next-2.6, thanks!