ipv6: Send unsolicited neighbour advertismements when notified

The NETDEV_NOTIFY_PEERS notifier is a request to send such
advertisements following migration to a different physical link,
e.g. virtual machine migration.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 26 insertions, 0 deletions

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index f057ff312840..62cbd15b4cde 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -611,6 +611,29 @@ static void ndisc_send_na(struct net_device *dev, struct neighbour *neigh,
                      inc_opt ? ND_OPT_TARGET_LL_ADDR : 0);
 }
 
+static void ndisc_send_unsol_na(struct net_device *dev)
+{
+        struct inet6_dev *idev;
+        struct inet6_ifaddr *ifa;
+        struct in6_addr mcaddr;
+
+        idev = in6_dev_get(dev);
+        if (!idev)
+                return;
+
+        read_lock_bh(&idev->lock);
+        list_for_each_entry(ifa, &idev->addr_list, if_list) {
+                addrconf_addr_solict_mult(&ifa->addr, &mcaddr);
+                ndisc_send_na(dev, NULL, &mcaddr, &ifa->addr,
+                              /*router=*/ !!idev->cnf.forwarding,
+                              /*solicited=*/ false, /*override=*/ true,
+                              /*inc_opt=*/ true);
+        }
+        read_unlock_bh(&idev->lock);
+
+        in6_dev_put(idev);
+}
+
 void ndisc_send_ns(struct net_device *dev, struct neighbour *neigh,
                    const struct in6_addr *solicit,
                    const struct in6_addr *daddr, const struct in6_addr *saddr)
@@ -1723,6 +1746,9 @@ static int ndisc_netdev_event(struct notifier_block *this, unsigned long event,
                 neigh_ifdown(&nd_tbl, dev);
                 fib6_run_gc(~0UL, net);
                 break;
+        case NETDEV_NOTIFY_PEERS:
+                ndisc_send_unsol_na(dev);
+                break;
         default:
                 break;
         }