ipv6: clean up anycast when an interface is destroyed

If we try to rmmod the driver for an interface while sockets with
setsockopt(JOIN_ANYCAST) are alive, some refcounts aren't cleaned up
and we get stuck on:

  unregister_netdevice: waiting for ens3 to become free. Usage count = 1

If we LEAVE_ANYCAST/close everything before rmmod'ing, there is no
problem.

We need to perform a cleanup similar to the one for multicast in
addrconf_ifdown(how == 1).

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 21 insertions, 0 deletions

diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index ff2de7d9d8e6..9a386842fd62 100644
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -351,6 +351,27 @@ static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr)
         return __ipv6_dev_ac_dec(idev, addr);
 }
 
+void ipv6_ac_destroy_dev(struct inet6_dev *idev)
+{
+        struct ifacaddr6 *aca;
+
+        write_lock_bh(&idev->lock);
+        while ((aca = idev->ac_list) != NULL) {
+                idev->ac_list = aca->aca_next;
+                write_unlock_bh(&idev->lock);
+
+                addrconf_leave_solict(idev, &aca->aca_addr);
+
+                dst_hold(&aca->aca_rt->dst);
+                ip6_del_rt(aca->aca_rt);
+
+                aca_put(aca);
+
+                write_lock_bh(&idev->lock);
+        }
+        write_unlock_bh(&idev->lock);
+}
+
 /*
  *      check if the interface has this anycast address
  *      called with rcu_read_lock()