IPV6: Restore IPv6 when MTU is big enough

[IPV6]: Restore IPv6 when MTU is big enough

[ Upstream commit: d31c7b8fa303eb81311f27b80595b8d2cbeef950 ]

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>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 45b4c82148a065b43a4a3e14648032a69f00721d..09179449db8629c7a4205499fd5900f52878b218 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2281,6 +2281,9 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event,
                                break;
                        }
 
+                       if (!idev && dev->mtu >= IPV6_MIN_MTU)
+                               idev = ipv6_add_dev(dev);
+
                        if (idev)
                                idev->if_flags |= IF_READY;
                } else {
@@ -2345,12 +2348,18 @@ 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: