Discussion:
[PATCH net-next v2] bridge: also trigger RTM_NEWLINK when interface is released from bridge
(too old to reply)
David Miller
2017-09-20 21:09:56 UTC
Permalink
From: Vincent Bernat <***@bernat.im>
Date: Sat, 16 Sep 2017 16:18:33 +0200

David, I am CC:'ing you because you've done work in this area over the
past year. I'm applying this patch, it's been sitting since the 16th
and likes entirely correct to me. But if you have objections just let
me know.
Currently, when an interface is released from a bridge via
Deleted 2: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> 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
Deleted 2: dummy0: <BROADCAST,NOARP> mtu 1500 master bridge0 state DOWN
link/ether 6e:23:c2:54:3a:b3
Deleted 2: dummy0: <BROADCAST,NOARP> 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
3: dummy1: <BROADCAST,NOARP,SLAVE,UP,LOWER_UP> 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: <BROADCAST,NOARP,UP,LOWER_UP> 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: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> 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: <BROADCAST,NOARP> 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: <BROADCAST,NOARP> 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: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> 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: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 8a:bb:e7:94:b1:f8
2: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> 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().
Applied, thank you.
David Ahern
2017-09-20 21:57:16 UTC
Permalink
Post by David Miller
Date: Sat, 16 Sep 2017 16:18:33 +0200
David, I am CC:'ing you because you've done work in this area over the
past year. I'm applying this patch, it's been sitting since the 16th
and likes entirely correct to me. But if you have objections just let
me know.
Currently, when an interface is released from a bridge via
Deleted 2: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> 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
Deleted 2: dummy0: <BROADCAST,NOARP> mtu 1500 master bridge0 state DOWN
link/ether 6e:23:c2:54:3a:b3
Deleted 2: dummy0: <BROADCAST,NOARP> 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
3: dummy1: <BROADCAST,NOARP,SLAVE,UP,LOWER_UP> 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: <BROADCAST,NOARP,UP,LOWER_UP> 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: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> 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: <BROADCAST,NOARP> 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: <BROADCAST,NOARP> 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: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> 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: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 8a:bb:e7:94:b1:f8
2: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> 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().
The DELLINK is for AF_BRIDGE family (ifi_family). Adding family to
print_linkinfo and running the monitor I get:


[LINK]family 0: 35: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc
noqueue master br0 state UNKNOWN group default
link/ether d6:c3:73:86:3c:73 brd ff:ff:ff:ff:ff:ff

[LINK]family 7: 35: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500
master br0 state UNKNOWN
link/ether d6:c3:73:86:3c:73

[LINK]Deleted family 7: 35: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu
1500 master br0 state UNKNOWN
link/ether d6:c3:73:86:3c:73

[LINK]family 0: 35: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc
noqueue state UNKNOWN group default
link/ether d6:c3:73:86:3c:73 brd ff:ff:ff:ff:ff:ff

And that seems correct. So I think the RTM_NEWLINK added by this patch
should not be needed.
David Miller
2017-09-20 22:41:17 UTC
Permalink
From: Vincent Bernat <***@bernat.im>
Date: Thu, 21 Sep 2017 00:12:53 +0200
Post by David Ahern
The DELLINK is for AF_BRIDGE family (ifi_family). Adding family to
[LINK]family 0: 35: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc
noqueue master br0 state UNKNOWN group default
link/ether d6:c3:73:86:3c:73 brd ff:ff:ff:ff:ff:ff
[LINK]family 7: 35: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500
master br0 state UNKNOWN
link/ether d6:c3:73:86:3c:73
[LINK]Deleted family 7: 35: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu
1500 master br0 state UNKNOWN
link/ether d6:c3:73:86:3c:73
I didn't know about the family. We can drop the patch.
Ok, I've reverted.

Th
Stephen Hemminger
2017-09-20 23:21:40 UTC
Permalink
On Wed, 20 Sep 2017 15:57:16 -0600
Post by David Ahern
Post by David Miller
Date: Sat, 16 Sep 2017 16:18:33 +0200
David, I am CC:'ing you because you've done work in this area over the
past year. I'm applying this patch, it's been sitting since the 16th
and likes entirely correct to me. But if you have objections just let
me know.
Currently, when an interface is released from a bridge via
Deleted 2: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> 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
Deleted 2: dummy0: <BROADCAST,NOARP> mtu 1500 master bridge0 state DOWN
link/ether 6e:23:c2:54:3a:b3
Deleted 2: dummy0: <BROADCAST,NOARP> 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
3: dummy1: <BROADCAST,NOARP,SLAVE,UP,LOWER_UP> 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: <BROADCAST,NOARP,UP,LOWER_UP> 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: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> 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: <BROADCAST,NOARP> 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: <BROADCAST,NOARP> 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: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> 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: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 8a:bb:e7:94:b1:f8
2: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> 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().
The DELLINK is for AF_BRIDGE family (ifi_family). Adding family to
[LINK]family 0: 35: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc
noqueue master br0 state UNKNOWN group default
link/ether d6:c3:73:86:3c:73 brd ff:ff:ff:ff:ff:ff
[LINK]family 7: 35: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500
master br0 state UNKNOWN
link/ether d6:c3:73:86:3c:73
[LINK]Deleted family 7: 35: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu
1500 master br0 state UNKNOWN
link/ether d6:c3:73:86:3c:73
[LINK]family 0: 35: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc
noqueue state UNKNOWN group default
link/ether d6:c3:73:86:3c:73 brd ff:ff:ff:ff:ff:ff
And that seems correct. So I think the RTM_NEWLINK added by this patch
should not be needed.
Agreed, thanks for tracing this.

The one concern is that ports added or removed through ioctl should
cause same events as doing the same thing via netlink. Some users use
brctl (ioctl) and others use newer bridge (netlink) API.
Roopa Prabhu
2017-09-21 15:09:28 UTC
Permalink
Post by Stephen Hemminger
The one concern is that ports added or removed through ioctl should
cause same events as doing the same thing via netlink. Some users use
brctl (ioctl) and others use newer bridge (netlink) API.
I'll make a third iteration to have the same notifications when using
ioctl() with details in the commit message.
--
as long as the ioctl path for bridge port removal is generating a:
RTM_DELLINK with AF_BRIDGE and
RTM_NEWLINK with AF_UNSPEC with 'master' removed

we should be good. These are the most important ones.

are there other specific bridge-events missing ?. you might want to
run `bridge monitor link` also. and un-slaving of a port also triggers
fdb events which are visible under `bridge monitor fdb`
Vincent Bernat
2017-09-21 15:31:32 UTC
Permalink
Post by Roopa Prabhu
Post by Stephen Hemminger
The one concern is that ports added or removed through ioctl should
cause same events as doing the same thing via netlink. Some users use
brctl (ioctl) and others use newer bridge (netlink) API.
I'll make a third iteration to have the same notifications when using
ioctl() with details in the commit message.
--
RTM_DELLINK with AF_BRIDGE and
RTM_NEWLINK with AF_UNSPEC with 'master' removed
we should be good. These are the most important ones.
are there other specific bridge-events missing ?. you might want to
run `bridge monitor link` also. and un-slaving of a port also triggers
fdb events which are visible under `bridge monitor fdb`
With the patch, bridge monitor link generates the same event with
ioctl() than with netlink (like for ip monitor link, netlink generates
one extra duplicate event when enslaving).

For bridge monitor fdb, there is a difference. With ioctl(), I don't get
the event for VLAN1:

Deleted ca:18:06:bc:f6:11 dev dummy1 vlan 1 master bridge0 permanent

I suppose this is an expected difference due to the inability to manage
VLAN-aware bridges with ioctl().
--
Use the fundamental control flow constructs.
- The Elements of Programming Style (Kernighan & Plauger)
Stephen Hemminger
2017-09-21 15:15:42 UTC
Permalink
On Thu, 21 Sep 2017 12:05:25 +0200
Currently, there is a difference in netlink events received when an
interface is modified through bridge ioctl() or through netlink. This
patch generates additional events when an interface is added to or
removed from a bridge via ioctl().
When adding then removing an interface from a bridge with netlink, we
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
Deleted 5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
Deleted 5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
Without this patch, the last netlink notification is not sent.
This makes sense, you should probably add a Fixes: tag to help maintainers
of long term stable kernels.

Reviewed-by: Stephen Hemminger <***@networkplumber.org>
Vincent Bernat
2017-09-21 15:45:17 UTC
Permalink
Post by Stephen Hemminger
Currently, there is a difference in netlink events received when an
interface is modified through bridge ioctl() or through netlink. This
patch generates additional events when an interface is added to or
removed from a bridge via ioctl().
When adding then removing an interface from a bridge with netlink, we
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
Deleted 5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
Deleted 5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
Without this patch, the last netlink notification is not sent.
This makes sense, you should probably add a Fixes: tag to help maintainers
of long term stable kernels.
I wouldn't know which commit would be fixed since this is not a
regression, just a behavior difference.
--
Make sure special cases are truly special.
- The Elements of Programming Style (Kernighan & Plauger)
David Ahern
2017-09-21 16:43:35 UTC
Permalink
Currently, there is a difference in netlink events received when an
interface is modified through bridge ioctl() or through netlink. This
patch generates additional events when an interface is added to or
removed from a bridge via ioctl().
When adding then removing an interface from a bridge with netlink, we
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
Deleted 5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
Deleted 5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
Without this patch, the last netlink notification is not sent.
---
net/bridge/br_ioctl.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c
index 7970f8540cbb..66cd98772051 100644
--- a/net/bridge/br_ioctl.c
+++ b/net/bridge/br_ioctl.c
@@ -102,6 +102,9 @@ static int add_del_if(struct net_bridge *br, int ifindex, int isadd)
else
ret = br_del_if(br, dev);
+ if (!ret)
+ rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_MASTER, GFP_KERNEL);
+
return ret;
}
Agreed that this is needed for userspace to know about the master change
when done through ioctl. The bridge code is emitting a lot of what
appears to be redundant messages for both paths (netlink and ioctl).

Reviewed-by: David Ahern <***@gmail.com>
Roopa Prabhu
2017-09-21 17:20:12 UTC
Permalink
Post by David Ahern
Currently, there is a difference in netlink events received when an
interface is modified through bridge ioctl() or through netlink. This
patch generates additional events when an interface is added to or
removed from a bridge via ioctl().
When adding then removing an interface from a bridge with netlink, we
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
Deleted 5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue master bridge0 state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
Deleted 5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 master bridge0 state UNKNOWN
link/ether 9e:da:60:ee:cf:c8
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default
link/ether 9e:da:60:ee:cf:c8 brd ff:ff:ff:ff:ff:ff
Without this patch, the last netlink notification is not sent.
---
net/bridge/br_ioctl.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c
index 7970f8540cbb..66cd98772051 100644
--- a/net/bridge/br_ioctl.c
+++ b/net/bridge/br_ioctl.c
@@ -102,6 +102,9 @@ static int add_del_if(struct net_bridge *br, int ifindex, int isadd)
else
ret = br_del_if(br, dev);
+ if (!ret)
+ rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_MASTER, GFP_KERNEL);
+
return ret;
}
Agreed that this is needed for userspace to know about the master change
when done through ioctl. The bridge code is emitting a lot of what
appears to be redundant messages for both paths (netlink and ioctl).
this patch seems fine...but ideally I would have assumed
netdev_upper_dev_unlink which
is eventually called in both paths would generate the RTN_NEWLINK
IFF_MASTER in response
to the NETDEV_CHANGEUPPER notifier. If we add it there now, it might
need some more fixes
to not generate redundant notifications for the netlink case.
David Ahern
2017-09-21 17:29:55 UTC
Permalink
Post by Roopa Prabhu
this patch seems fine...but ideally I would have assumed
netdev_upper_dev_unlink which
is eventually called in both paths would generate the RTN_NEWLINK
IFF_MASTER in response
to the NETDEV_CHANGEUPPER notifier. If we add it there now, it might
need some more fixes
to not generate redundant notifications for the netlink case.
Agreed and it is another pandora's box
David Miller
2017-09-21 22:45:32 UTC
Permalink
From: Vincent Bernat <***@bernat.im>
Date: Thu, 21 Sep 2017 12:05:25 +0200
Currently, there is a difference in netlink events received when an
interface is modified through bridge ioctl() or through netlink. This
patch generates additional events when an interface is added to or
removed from a bridge via ioctl().
...
Applied.
Continue reading on narkive:
Loading...