ipv4: Invalidate nexthop cache nh_saddr more correctly.

Any operation that:

1) Brings up an interface
2) Adds an IP address to an interface
3) Deletes an IP address from an interface

can potentially invalidate the nh_saddr value, requiring
it to be recomputed.

Perform the recomputation lazily using a generation ID.

Reported-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 4 deletions

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 02c3ba61884..f116ce8f1b4 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -228,7 +228,7 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
                 if (res.type != RTN_LOCAL || !accept_local)
                         goto e_inval;
         }
-        *spec_dst = FIB_RES_PREFSRC(res);
+        *spec_dst = FIB_RES_PREFSRC(net, res);
         fib_combine_itag(itag, &res);
         dev_match = false;
 
@@ -258,7 +258,7 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
         ret = 0;
         if (fib_lookup(net, &fl4, &res) == 0) {
                 if (res.type == RTN_UNICAST) {
-                        *spec_dst = FIB_RES_PREFSRC(res);
+                        *spec_dst = FIB_RES_PREFSRC(net, res);
                         ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
                 }
         }
@@ -960,6 +960,7 @@ static int fib_inetaddr_event(struct notifier_block *this, unsigned long event,
 {
         struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
         struct net_device *dev = ifa->ifa_dev->dev;
+        struct net *net = dev_net(dev);
 
         switch (event) {
         case NETDEV_UP:
@@ -967,12 +968,12 @@ static int fib_inetaddr_event(struct notifier_block *this, unsigned long event,
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
                 fib_sync_up(dev);
 #endif
-                fib_update_nh_saddrs(dev);
+                atomic_inc(&net->ipv4.dev_addr_genid);
                 rt_cache_flush(dev_net(dev), -1);
                 break;
         case NETDEV_DOWN:
                 fib_del_ifaddr(ifa, NULL);
-                fib_update_nh_saddrs(dev);
+                atomic_inc(&net->ipv4.dev_addr_genid);
                 if (ifa->ifa_dev->ifa_list == NULL) {
                         /* Last address was deleted from this interface.
                          * Disable IP.
@@ -990,6 +991,7 @@ static int fib_netdev_event(struct notifier_block *this, unsigned long event, vo
 {
         struct net_device *dev = ptr;
         struct in_device *in_dev = __in_dev_get_rtnl(dev);
+        struct net *net = dev_net(dev);
 
         if (event == NETDEV_UNREGISTER) {
                 fib_disable_ip(dev, 2, -1);
@@ -1007,6 +1009,7 @@ static int fib_netdev_event(struct notifier_block *this, unsigned long event, vo
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
                 fib_sync_up(dev);
 #endif
+                atomic_inc(&net->ipv4.dev_addr_genid);
                 rt_cache_flush(dev_net(dev), -1);
                 break;
         case NETDEV_DOWN: