Re: [Bugme-new] [Bug 9440] New: Problem in joinning a socket to ipv6 multicast address in specific scenario

[Evgeniy Polyakov <johnpol@2ka.mipt.ru>]

Hi.

Avaid provided test application, so bug got fixed.

IPv6 addrconf removes ipv6 inner device from netdev each time cmu
changes and new value is less than IPV6_MIN_MTU (1280 bytes).
When mtu is changed and new value is greater than IPV6_MIN_MTU,
it does not add ipv6 addresses and inner device bac.

This patch fixes that.

Tested with Avaid's application, which works ok now.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 567664e..4f7e46c 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2357,12 +2358,18 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event,
 		break;
 
 	case NETDEV_CHANGEMTU:
-		if ( idev && dev->mtu >= IPV6_MIN_MTU) {
+		if (idev && dev->mtu >= IPV6_MIN_MTU) {
 			rt6_mtu_change(dev, dev->mtu);
 			idev->cnf.mtu6 = dev->mtu;
 			break;
 		}
 
+		if (!idev && dev->mtu >= IPV6_MIN_MTU) {
+			idev = ipv6_add_dev(dev);
+			if (idev)
+				break;
+		}
+
 		/* MTU falled under IPV6_MIN_MTU. Stop IPv6 on this interface. */
 
 	case NETDEV_DOWN:

-- 
	Evgeniy Polyakov