[IPV6]: Address autoconfiguration does not work after device down/up cycle

If you set network interface down and up again, the IPv6 address
autoconfiguration does not work. 'ip addr' shows that the link-local
address is in tentative state. We don't even react to periodical router
advertisements.

During NETDEV_DOWN we clear IF_READY, and we don't set it back in
NETDEV_UP. While starting to perform DAD on the link-local address, we
notice that the device is not in IF_READY, and we abort autoconfiguration
process (which would eventually send router solicitations).

Acked-by: Juha-Matti Tapio <jmtapio@verkkotelakka.net>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 1db50487916b..b7d8822c1be4 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2165,6 +2165,9 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event,
                                         dev->name);
                                 break;
                         }
+
+                        if (idev)
+                                idev->if_flags |= IF_READY;
                 } else {
                         if (!netif_carrier_ok(dev)) {
                                 /* device is still not ready. */