From 50d629e7a843d1635ecb1658335279503c4ec9a8 Mon Sep 17 00:00:00 2001 From: Mike Manning Date: Mon, 26 Feb 2018 23:49:30 +0000 Subject: [PATCH] net: allow interface to be set into VRF if VLAN interface in same VRF Setting an interface into a VRF fails with 'RTNETLINK answers: File exists' if one of its VLAN interfaces is already in the same VRF. As the VRF is an upper device of the VLAN interface, it is also showing up as an upper device of the interface itself. The solution is to restrict this check to devices other than master. As only one master device can be linked to a device, the check in this case is that the upper device (VRF) being linked to is not the same as the master device instead of it not being any one of the upper devices. The following example shows an interface ens12 (with a VLAN interface ens12.10) being set into VRF green, which behaves as expected: # ip link add link ens12 ens12.10 type vlan id 10 # ip link set dev ens12 master vrfgreen # ip link show dev ens12 3: ens12: mtu 1500 qdisc fq_codel master vrfgreen state UP mode DEFAULT group default qlen 1000 link/ether 52:54:00:4c:a0:45 brd ff:ff:ff:ff:ff:ff But if the VLAN interface has previously been set into the same VRF, then setting the interface into the VRF fails: # ip link set dev ens12 nomaster # ip link set dev ens12.10 master vrfgreen # ip link show dev ens12.10 39: ens12.10@ens12: mtu 1500 qdisc noqueue master vrfgreen state UP mode DEFAULT group default qlen 1000 link/ether 52:54:00:4c:a0:45 brd ff:ff:ff:ff:ff:ff # ip link set dev ens12 master vrfgreen RTNETLINK answers: File exists The workaround is to move the VLAN interface back into the default VRF beforehand, but it has to be shut first so as to avoid the risk of traffic leaking from the VRF. This fix avoids needing this workaround. Signed-off-by: Mike Manning Signed-off-by: David S. Miller --- net/core/dev.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index d4362befe7e2..2cedf520cb28 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6396,6 +6396,7 @@ static int __netdev_upper_dev_link(struct net_device *dev, .linking = true, .upper_info = upper_info, }; + struct net_device *master_dev; int ret = 0; ASSERT_RTNL(); @@ -6407,11 +6408,14 @@ static int __netdev_upper_dev_link(struct net_device *dev, if (netdev_has_upper_dev(upper_dev, dev)) return -EBUSY; - if (netdev_has_upper_dev(dev, upper_dev)) - return -EEXIST; - - if (master && netdev_master_upper_dev_get(dev)) - return -EBUSY; + if (!master) { + if (netdev_has_upper_dev(dev, upper_dev)) + return -EEXIST; + } else { + master_dev = netdev_master_upper_dev_get(dev); + if (master_dev) + return master_dev == upper_dev ? -EEXIST : -EBUSY; + } ret = call_netdevice_notifiers_info(NETDEV_PRECHANGEUPPER, &changeupper_info.info); -- 2.39.5