net: Support filtering interfaces on no master

Currently there's support for filtering neighbours/links for interfaces
which have a specific master device (using the IFLA_MASTER/NDA_MASTER
attributes).

This patch adds support for filtering interfaces/neighbours dump for
interfaces that *don't* have a master.

Signed-off-by: Lahav Schlesinger <lschlesinger@drivenets.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20210810090658.2778960-1-lschlesinger@drivenets.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index b963d6b..2d5bc3a 100644 (file)
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -2528,6 +2528,13 @@ static bool neigh_master_filtered(struct net_device *dev, int master_idx)
                return false;
 
        master = dev ? netdev_master_upper_dev_get(dev) : NULL;
+
+       /* 0 is already used to denote NDA_MASTER wasn't passed, therefore need another
+        * invalid value for ifindex to denote "no master".
+        */
+       if (master_idx == -1)
+               return !!master;
+
        if (!master || master->ifindex != master_idx)
                return true;
 

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 7c9d32c..2dcf1c0 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1959,6 +1959,13 @@ static bool link_master_filtered(struct net_device *dev, int master_idx)
                return false;
 
        master = netdev_master_upper_dev_get(dev);
+
+       /* 0 is already used to denote IFLA_MASTER wasn't passed, therefore need
+        * another invalid value for ifindex to denote "no master".
+        */
+       if (master_idx == -1)
+               return !!master;
+
        if (!master || master->ifindex != master_idx)
                return true;