From 00ba4cb36da682c68dc87d1703a8aaffe2b4e9c5 Mon Sep 17 00:00:00 2001 From: Vincent Bernat Date: Sat, 16 Sep 2017 16:18:33 +0200 Subject: [PATCH] bridge: also trigger RTM_NEWLINK when interface is released from bridge Currently, when an interface is released from a bridge via ioctl(), we get a RTM_DELLINK event through netlink: Deleted 2: dummy0: mtu 1500 master bridge0 state UNKNOWN link/ether 6e:23:c2:54:3a:b3 Userspace has to interpret that as a removal from the bridge, not as a complete removal of the interface. When an bridged interface is completely removed, we get two events: Deleted 2: dummy0: mtu 1500 master bridge0 state DOWN link/ether 6e:23:c2:54:3a:b3 Deleted 2: dummy0: mtu 1500 qdisc noop state DOWN group default link/ether 6e:23:c2:54:3a:b3 brd ff:ff:ff:ff:ff:ff In constrast, when an interface is released from a bond, we get a RTM_NEWLINK with only the new characteristics (no master): 3: dummy1: mtu 1500 qdisc noqueue master bond0 state UNKNOWN group default link/ether ae:dc:7a:8c:9a:3c brd ff:ff:ff:ff:ff:ff 3: dummy1: mtu 1500 qdisc noqueue state UNKNOWN group default link/ether ae:dc:7a:8c:9a:3c brd ff:ff:ff:ff:ff:ff 4: bond0: mtu 1500 qdisc noqueue state UP group default link/ether ae:dc:7a:8c:9a:3c brd ff:ff:ff:ff:ff:ff 3: dummy1: mtu 1500 qdisc noqueue state DOWN group default link/ether ae:dc:7a:8c:9a:3c brd ff:ff:ff:ff:ff:ff 3: dummy1: mtu 1500 qdisc noqueue state DOWN group default link/ether ca:c8:7b:66:f8:25 brd ff:ff:ff:ff:ff:ff 4: bond0: mtu 1500 qdisc noqueue state UP group default link/ether ae:dc:7a:8c:9a:3c brd ff:ff:ff:ff:ff:ff Userland may be confused by the fact we say a link is deleted while its characteristics are only modified. A first solution would have been to turn the RTM_DELLINK event in del_nbp() into a RTM_NEWLINK event. However, maybe some piece of userland is relying on this RTM_DELLINK to detect when a bridged interface is released. Instead, we also emit a RTM_NEWLINK event once the interface is released (without master info). Deleted 2: dummy0: mtu 1500 master bridge0 state UNKNOWN link/ether 8a:bb:e7:94:b1:f8 2: dummy0: mtu 1500 qdisc noqueue state UNKNOWN group default link/ether 8a:bb:e7:94:b1:f8 brd ff:ff:ff:ff:ff:ff This is done only when using ioctl(). When using Netlink, such an event is already automatically emitted in do_setlink(). Signed-off-by: Vincent Bernat Signed-off-by: David S. Miller --- net/bridge/br_ioctl.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c index 7970f85..3148cb3 100644 --- a/net/bridge/br_ioctl.c +++ b/net/bridge/br_ioctl.c @@ -99,8 +99,10 @@ static int add_del_if(struct net_bridge *br, int ifindex, int isadd) if (isadd) ret = br_add_if(br, dev); - else + else { ret = br_del_if(br, dev); + rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_MASTER, GFP_KERNEL); + } return ret; } -- 2.7.4