diff mbox

neigh: fix state transition INCOMPLETE->FAILED via Netlink request

Message ID 1244716345-9407-1-git-send-email-timo.teras@iki.fi
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Timo Teras June 11, 2009, 10:32 a.m. UTC 
The current code errors out the INCOMPLETE neigh entry skb queue only from
the timer if maximum probes have been attempted and there has been no reply.
This also causes the transtion to FAILED state.

However, the neigh entry can be also updated via Netlink to inform that the
address is unavailable.  Currently, neigh_update() just stops the timers and
leaves the pending skb's unreleased. This results that the clean up code in
the timer callback is never called, preventing also proper garbage collection.

This fixes neigh_update() to process the pending skb queue immediately if
INCOMPLETE -> FAILED state transtion occurs due to a Netlink request.

Signed-off-by: Timo Teras <timo.teras@iki.fi>
---
 net/core/neighbour.c |   46 ++++++++++++++++++++++++++++------------------
 1 files changed, 28 insertions(+), 18 deletions(-)

Comments

David Miller June 11, 2009, 11:16 a.m. UTC | #1 
From: Timo Teras <timo.teras@iki.fi>
Date: Thu, 11 Jun 2009 13:32:25 +0300

> The current code errors out the INCOMPLETE neigh entry skb queue only from
> the timer if maximum probes have been attempted and there has been no reply.
> This also causes the transtion to FAILED state.
> 
> However, the neigh entry can be also updated via Netlink to inform that the
> address is unavailable.  Currently, neigh_update() just stops the timers and
> leaves the pending skb's unreleased. This results that the clean up code in
> the timer callback is never called, preventing also proper garbage collection.
> 
> This fixes neigh_update() to process the pending skb queue immediately if
> INCOMPLETE -> FAILED state transtion occurs due to a Netlink request.
> 
> Signed-off-by: Timo Teras <timo.teras@iki.fi>

Looks great, applied, thanks!
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diff mbox

Patch

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index a1cbce7..a17cb9d 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -771,6 +771,28 @@  static __inline__ int neigh_max_probes(struct neighbour *n)
 		p->ucast_probes + p->app_probes + p->mcast_probes);
 }
 
+static void neigh_invalidate(struct neighbour *neigh)
+{
+	struct sk_buff *skb;
+
+	NEIGH_CACHE_STAT_INC(neigh->tbl, res_failed);
+	NEIGH_PRINTK2("neigh %p is failed.\n", neigh);
+	neigh->updated = jiffies;
+
+	/* It is very thin place. report_unreachable is very complicated
+	   routine. Particularly, it can hit the same neighbour entry!
+
+	   So that, we try to be accurate and avoid dead loop. --ANK
+	 */
+	while (neigh->nud_state == NUD_FAILED &&
+	       (skb = __skb_dequeue(&neigh->arp_queue)) != NULL) {
+		write_unlock(&neigh->lock);
+		neigh->ops->error_report(neigh, skb);
+		write_lock(&neigh->lock);
+	}
+	skb_queue_purge(&neigh->arp_queue);
+}
+
 /* Called when a timer expires for a neighbour entry. */
 
 static void neigh_timer_handler(unsigned long arg)
@@ -835,26 +857,9 @@  static void neigh_timer_handler(unsigned long arg)
 
 	if ((neigh->nud_state & (NUD_INCOMPLETE | NUD_PROBE)) &&
 	    atomic_read(&neigh->probes) >= neigh_max_probes(neigh)) {
-		struct sk_buff *skb;
-
 		neigh->nud_state = NUD_FAILED;
-		neigh->updated = jiffies;
 		notify = 1;
-		NEIGH_CACHE_STAT_INC(neigh->tbl, res_failed);
-		NEIGH_PRINTK2("neigh %p is failed.\n", neigh);
-
-		/* It is very thin place. report_unreachable is very complicated
-		   routine. Particularly, it can hit the same neighbour entry!
-
-		   So that, we try to be accurate and avoid dead loop. --ANK
-		 */
-		while (neigh->nud_state == NUD_FAILED &&
-		       (skb = __skb_dequeue(&neigh->arp_queue)) != NULL) {
-			write_unlock(&neigh->lock);
-			neigh->ops->error_report(neigh, skb);
-			write_lock(&neigh->lock);
-		}
-		skb_queue_purge(&neigh->arp_queue);
+		neigh_invalidate(neigh);
 	}
 
 	if (neigh->nud_state & NUD_IN_TIMER) {
@@ -1001,6 +1006,11 @@  int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
 		neigh->nud_state = new;
 		err = 0;
 		notify = old & NUD_VALID;
+		if ((old & (NUD_INCOMPLETE | NUD_PROBE)) &&
+		    (new & NUD_FAILED)) {
+			neigh_invalidate(neigh);
+			notify = 1;
+		}
 		goto out;
 	}