ipv4: Add ip_defrag() agent IP_DEFRAG_AF_PACKET.

Elide the ICMP on frag queue timeouts unconditionally for
this user.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/ip.h

@@ -404,7 +404,8 @@ enum ip_defrag_users {
 	__IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
 	IP_DEFRAG_VS_IN,
 	IP_DEFRAG_VS_OUT,
-	IP_DEFRAG_VS_FWD
+	IP_DEFRAG_VS_FWD,
+	IP_DEFRAG_AF_PACKET,
 };
 
 int ip_defrag(struct sk_buff *skb, u32 user);

net/ipv4/ip_fragment.c

@@ -261,8 +261,9 @@ static void ip_expire(unsigned long arg)
 		 * Only an end host needs to send an ICMP
 		 * "Fragment Reassembly Timeout" message, per RFC792.
 		 */
-		if (qp->user == IP_DEFRAG_CONNTRACK_IN &&
-		    skb_rtable(head)->rt_type != RTN_LOCAL)
+		if (qp->user == IP_DEFRAG_AF_PACKET ||
+		    (qp->user == IP_DEFRAG_CONNTRACK_IN &&
+		     skb_rtable(head)->rt_type != RTN_LOCAL))
 			goto out_rcu_unlock;