[PATCH 1/2] ipv6: Clamp reported valid_lft to a minimum of 0

[PATCH 1/2] ipv6: Clamp reported valid_lft to a minimum of 0

[Ben Hutchings]

Since addresses are only revalidated every 2 minutes, the reported
valid_lft can underflow shortly before the address is deleted.
Clamp it to a minimum of 0, as for prefered_lft.

Reported-by: Piotr Lewandowski <piotr.lewandowski@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
This is compile-tested only.  I don't claim any familiarity with this
code.

Ben.

 net/ipv6/addrconf.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index b97bb1f..1459eed 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3492,8 +3492,12 @@ static int inet6_fill_ifaddr(struct sk_buff *skb, struct inet6_ifaddr *ifa,
 				preferred -= tval;
 			else
 				preferred = 0;
-			if (valid != INFINITY_LIFE_TIME)
-				valid -= tval;
+			if (valid != INFINITY_LIFE_TIME) {
+				if (valid > tval)
+					valid -= tval;
+				else
+					valid = 0;
+			}
 		}
 	} else {
 		preferred = INFINITY_LIFE_TIME;
-- 
1.7.1

[PATCH 2/2] ipv6: Use interface max_desync_factor instead of static default

[Ben Hutchings]

max_desync_factor can be configured per-interface, but nothing is
using the value.

Reported-by: Piotr Lewandowski <piotr.lewandowski@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
Also compile-tested only.

Note that there is nothing to stop temp_prefered_lft being set smaller
than max_desync_factor, which can result in underflow in calculation of
tmp_prefered_lft in ipv6_create_tempaddr().  However, the same applies
to the current static variable desync_factor.

Ben.

 net/ipv6/addrconf.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 1459eed..ec8c92f 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -121,8 +121,6 @@ static inline void addrconf_sysctl_unregister(struct inet6_dev *idev)
 static int __ipv6_regen_rndid(struct inet6_dev *idev);
 static int __ipv6_try_regen_rndid(struct inet6_dev *idev, struct in6_addr *tmpaddr);
 static void ipv6_regen_rndid(unsigned long data);
-
-static int desync_factor = MAX_DESYNC_FACTOR * HZ;
 #endif
 
 static int ipv6_generate_eui64(u8 *eui, struct net_device *dev);
@@ -890,7 +888,8 @@ retry:
 			      idev->cnf.temp_valid_lft);
 	tmp_prefered_lft = min_t(__u32,
 				 ifp->prefered_lft,
-				 idev->cnf.temp_prefered_lft - desync_factor / HZ);
+				 idev->cnf.temp_prefered_lft -
+				 idev->cnf.max_desync_factor);
 	tmp_plen = ifp->prefix_len;
 	max_addresses = idev->cnf.max_addresses;
 	tmp_cstamp = ifp->cstamp;
@@ -1650,7 +1649,8 @@ static void ipv6_regen_rndid(unsigned long data)
 
 	expires = jiffies +
 		idev->cnf.temp_prefered_lft * HZ -
-		idev->cnf.regen_max_retry * idev->cnf.dad_transmits * idev->nd_parms->retrans_time - desync_factor;
+		idev->cnf.regen_max_retry * idev->cnf.dad_transmits * idev->nd_parms->retrans_time -
+		idev->cnf.max_desync_factor * HZ;
 	if (time_before(expires, jiffies)) {
 		printk(KERN_WARNING
 			"ipv6_regen_rndid(): too short regeneration interval; timer disabled for %s.\n",
-- 
1.7.1

Re: [PATCH 1/2] ipv6: Clamp reported valid_lft to a minimum of 0

[David Miller]

From: Ben Hutchings <ben@decadent.org.uk>
Date: Sat, 26 Jun 2010 22:37:47 +0100

> Since addresses are only revalidated every 2 minutes, the reported
> valid_lft can underflow shortly before the address is deleted.
> Clamp it to a minimum of 0, as for prefered_lft.
> 
> Reported-by: Piotr Lewandowski <piotr.lewandowski@gmail.com>
> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

Applied to net-next-2.6

Re: [PATCH 2/2] ipv6: Use interface max_desync_factor instead of static default

[David Miller]

From: Ben Hutchings <ben@decadent.org.uk>
Date: Sat, 26 Jun 2010 22:42:55 +0100

> max_desync_factor can be configured per-interface, but nothing is
> using the value.
> 
> Reported-by: Piotr Lewandowski <piotr.lewandowski@gmail.com>
> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

Applied to net-next-2.6