inet: frags: use INET_FRAG_EVICTED to prevent icmp messages

Now that we have INET_FRAG_EVICTED we might as well use it to stop
sending icmp messages in the "frag_expire" functions instead of
stripping INET_FRAG_FIRST_IN from their flags when evicting.
Also fix the comment style in ip6_expire_frag_queue().

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/inet_fragment.c

@@ -151,8 +151,6 @@ inet_evict_bucket(struct inet_frags *f, struct inet_frag_bucket *hb)
 			goto evict_again;
 		}
 
-		/* suppress xmit of (icmp) error packet */
-		fq->flags &= ~INET_FRAG_FIRST_IN;
 		fq->flags |= INET_FRAG_EVICTED;
 		hlist_del(&fq->list);
 		hlist_add_head(&fq->list, &expired);

net/ipv4/ip_fragment.c

@@ -189,16 +189,18 @@ static void ip_expire(unsigned long arg)
 		goto out;
 
 	ipq_kill(qp);
-
-	if (!(qp->q.flags & INET_FRAG_EVICTED))
-		IP_INC_STATS_BH(net, IPSTATS_MIB_REASMTIMEOUT);
 	IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS);
 
-	if ((qp->q.flags & INET_FRAG_FIRST_IN) && qp->q.fragments != NULL) {
+	if (!(qp->q.flags & INET_FRAG_EVICTED)) {
 		struct sk_buff *head = qp->q.fragments;
 		const struct iphdr *iph;
 		int err;
 
+		IP_INC_STATS_BH(net, IPSTATS_MIB_REASMTIMEOUT);
+
+		if (!(qp->q.flags & INET_FRAG_FIRST_IN) || !qp->q.fragments)
+			goto out;
+
 		rcu_read_lock();
 		head->dev = dev_get_by_index_rcu(net, qp->iif);
 		if (!head->dev)
@@ -211,8 +213,7 @@ static void ip_expire(unsigned long arg)
 		if (err)
 			goto out_rcu_unlock;
 
-		/*
-		 * Only an end host needs to send an ICMP
+		/* Only an end host needs to send an ICMP
 		 * "Fragment Reassembly Timeout" message, per RFC792.
 		 */
 		if (qp->user == IP_DEFRAG_AF_PACKET ||
@@ -221,7 +222,6 @@ static void ip_expire(unsigned long arg)
 		     (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:

net/ipv6/reassembly.c

@@ -141,19 +141,20 @@ void ip6_expire_frag_queue(struct net *net, struct frag_queue *fq,
 	if (!dev)
 		goto out_rcu_unlock;
 
-	if (!(fq->q.flags & INET_FRAG_EVICTED))
-		IP6_INC_STATS_BH(net, __in6_dev_get(dev),
-				 IPSTATS_MIB_REASMTIMEOUT);
 	IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 
+	if (fq->q.flags & INET_FRAG_EVICTED)
+		goto out_rcu_unlock;
+
+	IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
+
 	/* Don't send error if the first segment did not arrive. */
 	if (!(fq->q.flags & INET_FRAG_FIRST_IN) || !fq->q.fragments)
 		goto out_rcu_unlock;
 
-	/*
-	   But use as source device on which LAST ARRIVED
-	   segment was received. And do not use fq->dev
-	   pointer directly, device might already disappeared.
+	/* But use as source device on which LAST ARRIVED
+	 * segment was received. And do not use fq->dev
+	 * pointer directly, device might already disappeared.
 	 */
 	fq->q.fragments->dev = dev;
 	icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);