1 files changed, 32 insertions, 7 deletions

diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 86964b3..b59430b 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -32,6 +32,8 @@
 #include <linux/netdevice.h>
 #include <linux/jhash.h>
 #include <linux/random.h>
+#include <net/route.h>
+#include <net/dst.h>
 #include <net/sock.h>
 #include <net/ip.h>
 #include <net/icmp.h>
@@ -205,11 +207,34 @@ static void ip_expire(unsigned long arg)
 	if ((qp->q.last_in & INET_FRAG_FIRST_IN) && qp->q.fragments != NULL) {
 		struct sk_buff *head = qp->q.fragments;
 
-		/* Send an ICMP "Fragment Reassembly Timeout" message. */
 		rcu_read_lock();
 		head->dev = dev_get_by_index_rcu(net, qp->iif);
-		if (head->dev)
-			icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0);
+		if (!head->dev)
+			goto out_rcu_unlock;
+
+		/*
+		 * Only search router table for the head fragment,
+		 * when defraging timeout at PRE_ROUTING HOOK.
+		 */
+		if (qp->user == IP_DEFRAG_CONNTRACK_IN && !skb_dst(head)) {
+			const struct iphdr *iph = ip_hdr(head);
+			int err = ip_route_input(head, iph->daddr, iph->saddr,
+						 iph->tos, head->dev);
+			if (unlikely(err))
+				goto out_rcu_unlock;
+
+			/*
+			 * Only an end host needs to send an ICMP
+			 * "Fragment Reassembly Timeout" message, per RFC792.
+			 */
+			if (skb_rtable(head)->rt_type != RTN_LOCAL)
+				goto out_rcu_unlock;
+
+		}
+
+		/* Send an ICMP "Fragment Reassembly Timeout" message. */
+		icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0);
+out_rcu_unlock:
 		rcu_read_unlock();
 	}
 out:
@@ -646,7 +671,7 @@ static struct ctl_table ip4_frags_ctl_table[] = {
 	{ }
 };
 
-static int ip4_frags_ns_ctl_register(struct net *net)
+static int __net_init ip4_frags_ns_ctl_register(struct net *net)
 {
 	struct ctl_table *table;
 	struct ctl_table_header *hdr;
@@ -676,7 +701,7 @@ err_alloc:
 	return -ENOMEM;
 }
 
-static void ip4_frags_ns_ctl_unregister(struct net *net)
+static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net)
 {
 	struct ctl_table *table;
 
@@ -704,7 +729,7 @@ static inline void ip4_frags_ctl_register(void)
 }
 #endif
 
-static int ipv4_frags_init_net(struct net *net)
+static int __net_init ipv4_frags_init_net(struct net *net)
 {
 	/*
 	 * Fragment cache limits. We will commit 256K at one time. Should we
@@ -726,7 +751,7 @@ static int ipv4_frags_init_net(struct net *net)
 	return ip4_frags_ns_ctl_register(net);
 }
 
-static void ipv4_frags_exit_net(struct net *net)
+static void __net_exit ipv4_frags_exit_net(struct net *net)
 {
 	ip4_frags_ns_ctl_unregister(net);
 	inet_frags_exit_net(&net->ipv4.frags, &ip4_frags);