[patch net-next 1/2] rtnetlink: allow to register ops without ops->setup set

[patch net-next 1/2] rtnetlink: allow to register ops without ops->setup set

[Jiri Pirko]

So far, it is assumed that ops->setup is filled up. But there might be
case that ops might make sense even without ->setup. In that case,
forbid to newlink and dellink.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
---
 net/core/rtnetlink.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 1063996..84affd7 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1777,7 +1777,7 @@ static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh)
 		return -ENODEV;
 
 	ops = dev->rtnl_link_ops;
-	if (!ops)
+	if (!ops || !ops->setup)
 		return -EOPNOTSUPP;
 
 	ops->dellink(dev, &list_kill);
@@ -2038,6 +2038,9 @@ replay:
 			return -EOPNOTSUPP;
 		}
 
+		if (!ops->setup)
+			return -EOPNOTSUPP;
+
 		if (!ifname[0])
 			snprintf(ifname, IFNAMSIZ, "%s%%d", ops->kind);
 
-- 
1.9.0

[patch net-next 2/2] openvswitch: introduce rtnl ops stub

[Jiri Pirko]

This stub now allows userspace to see IFLA_INFO_KIND for ovs master and
IFLA_INFO_SLAVE_KIND for slave.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
---
 net/openvswitch/datapath.c           |  9 ++++++++-
 net/openvswitch/vport-internal_dev.c | 16 ++++++++++++++++
 net/openvswitch/vport-internal_dev.h |  2 ++
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 0d407bc..fe95b6c 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -2054,10 +2054,14 @@ static int __init dp_init(void)
 
 	pr_info("Open vSwitch switching datapath\n");
 
-	err = ovs_flow_init();
+	err = ovs_internal_dev_rtnl_link_register();
 	if (err)
 		goto error;
 
+	err = ovs_flow_init();
+	if (err)
+		goto error_unreg_rtnl_link;
+
 	err = ovs_vport_init();
 	if (err)
 		goto error_flow_exit;
@@ -2084,6 +2088,8 @@ error_vport_exit:
 	ovs_vport_exit();
 error_flow_exit:
 	ovs_flow_exit();
+error_unreg_rtnl_link:
+	ovs_internal_dev_rtnl_link_unregister();
 error:
 	return err;
 }
@@ -2096,6 +2102,7 @@ static void dp_cleanup(void)
 	rcu_barrier();
 	ovs_vport_exit();
 	ovs_flow_exit();
+	ovs_internal_dev_rtnl_link_unregister();
 }
 
 module_init(dp_init);
diff --git a/net/openvswitch/vport-internal_dev.c b/net/openvswitch/vport-internal_dev.c
index 789af92..295471a 100644
--- a/net/openvswitch/vport-internal_dev.c
+++ b/net/openvswitch/vport-internal_dev.c
@@ -26,6 +26,7 @@
 
 #include <net/dst.h>
 #include <net/xfrm.h>
+#include <net/rtnetlink.h>
 
 #include "datapath.h"
 #include "vport-internal_dev.h"
@@ -121,6 +122,10 @@ static const struct net_device_ops internal_dev_netdev_ops = {
 	.ndo_get_stats64 = internal_dev_get_stats,
 };
 
+static struct rtnl_link_ops internal_dev_link_ops __read_mostly = {
+	.kind = "openvswitch",
+};
+
 static void do_setup(struct net_device *netdev)
 {
 	ether_setup(netdev);
@@ -131,6 +136,7 @@ static void do_setup(struct net_device *netdev)
 	netdev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
 	netdev->destructor = internal_dev_destructor;
 	netdev->ethtool_ops = &internal_dev_ethtool_ops;
+	netdev->rtnl_link_ops = &internal_dev_link_ops;
 	netdev->tx_queue_len = 0;
 
 	netdev->features = NETIF_F_LLTX | NETIF_F_SG | NETIF_F_FRAGLIST |
@@ -248,3 +254,13 @@ struct vport *ovs_internal_dev_get_vport(struct net_device *netdev)
 
 	return internal_dev_priv(netdev)->vport;
 }
+
+int ovs_internal_dev_rtnl_link_register(void)
+{
+	return rtnl_link_register(&internal_dev_link_ops);
+}
+
+void ovs_internal_dev_rtnl_link_unregister(void)
+{
+	rtnl_link_unregister(&internal_dev_link_ops);
+}
diff --git a/net/openvswitch/vport-internal_dev.h b/net/openvswitch/vport-internal_dev.h
index 9a7d30e..1b179a1 100644
--- a/net/openvswitch/vport-internal_dev.h
+++ b/net/openvswitch/vport-internal_dev.h
@@ -24,5 +24,7 @@
 
 int ovs_is_internal_dev(const struct net_device *);
 struct vport *ovs_internal_dev_get_vport(struct net_device *);
+int ovs_internal_dev_rtnl_link_register(void);
+void ovs_internal_dev_rtnl_link_unregister(void);
 
 #endif /* vport-internal_dev.h */
-- 
1.9.0

Re: [patch net-next 1/2] rtnetlink: allow to register ops without ops->setup set

[Eric W. Biederman]

Jiri Pirko <jiri@resnulli.us> writes:

> So far, it is assumed that ops->setup is filled up. But there might be
> case that ops might make sense even without ->setup. In that case,
> forbid to newlink and dellink.

This patch does not handle all cases of dellink, and so you have created
a way to oops the kernel.  One case that is not handled is
default_device_exit_batch.

Further using !setup to prevent dellink does not make any kind of
logical sense.  Which leads to a maintenance hazard.  Aka how can we
further update this code without running into weird corner cases.

Further you have not given a description why anyone would want to have
something that is almost completely unlike rtnl link operations
implemented with the rtnl link operations.


> Signed-off-by: Jiri Pirko <jiri@resnulli.us>
> ---
>  net/core/rtnetlink.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index 1063996..84affd7 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -1777,7 +1777,7 @@ static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh)
>  		return -ENODEV;
>  
>  	ops = dev->rtnl_link_ops;
> -	if (!ops)
> +	if (!ops || !ops->setup)
>  		return -EOPNOTSUPP;
>  
>  	ops->dellink(dev, &list_kill);
> @@ -2038,6 +2038,9 @@ replay:
>  			return -EOPNOTSUPP;
>  		}
>  
> +		if (!ops->setup)
> +			return -EOPNOTSUPP;
> +
>  		if (!ifname[0])
>  			snprintf(ifname, IFNAMSIZ, "%s%%d", ops->kind);

Re: [patch net-next 2/2] openvswitch: introduce rtnl ops stub

[Eric W. Biederman]

Jiri Pirko <jiri@resnulli.us> writes:

> This stub now allows userspace to see IFLA_INFO_KIND for ovs master and
> IFLA_INFO_SLAVE_KIND for slave.

I am puzzled why you don't implement full rtnl_link_operations support.

If all you want is to report which kind of driver you have I suspect
implementing ethtool_ops.get_drvinfo is a much better fit.

Eric

> Signed-off-by: Jiri Pirko <jiri@resnulli.us>
> ---
>  net/openvswitch/datapath.c           |  9 ++++++++-
>  net/openvswitch/vport-internal_dev.c | 16 ++++++++++++++++
>  net/openvswitch/vport-internal_dev.h |  2 ++
>  3 files changed, 26 insertions(+), 1 deletion(-)
>
> diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
> index 0d407bc..fe95b6c 100644
> --- a/net/openvswitch/datapath.c
> +++ b/net/openvswitch/datapath.c
> @@ -2054,10 +2054,14 @@ static int __init dp_init(void)
>  
>  	pr_info("Open vSwitch switching datapath\n");
>  
> -	err = ovs_flow_init();
> +	err = ovs_internal_dev_rtnl_link_register();
>  	if (err)
>  		goto error;
>  
> +	err = ovs_flow_init();
> +	if (err)
> +		goto error_unreg_rtnl_link;
> +
>  	err = ovs_vport_init();
>  	if (err)
>  		goto error_flow_exit;
> @@ -2084,6 +2088,8 @@ error_vport_exit:
>  	ovs_vport_exit();
>  error_flow_exit:
>  	ovs_flow_exit();
> +error_unreg_rtnl_link:
> +	ovs_internal_dev_rtnl_link_unregister();
>  error:
>  	return err;
>  }
> @@ -2096,6 +2102,7 @@ static void dp_cleanup(void)
>  	rcu_barrier();
>  	ovs_vport_exit();
>  	ovs_flow_exit();
> +	ovs_internal_dev_rtnl_link_unregister();
>  }
>  
>  module_init(dp_init);
> diff --git a/net/openvswitch/vport-internal_dev.c b/net/openvswitch/vport-internal_dev.c
> index 789af92..295471a 100644
> --- a/net/openvswitch/vport-internal_dev.c
> +++ b/net/openvswitch/vport-internal_dev.c
> @@ -26,6 +26,7 @@
>  
>  #include <net/dst.h>
>  #include <net/xfrm.h>
> +#include <net/rtnetlink.h>
>  
>  #include "datapath.h"
>  #include "vport-internal_dev.h"
> @@ -121,6 +122,10 @@ static const struct net_device_ops internal_dev_netdev_ops = {
>  	.ndo_get_stats64 = internal_dev_get_stats,
>  };
>  
> +static struct rtnl_link_ops internal_dev_link_ops __read_mostly = {
> +	.kind = "openvswitch",
> +};
> +
>  static void do_setup(struct net_device *netdev)
>  {
>  	ether_setup(netdev);
> @@ -131,6 +136,7 @@ static void do_setup(struct net_device *netdev)
>  	netdev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
>  	netdev->destructor = internal_dev_destructor;
>  	netdev->ethtool_ops = &internal_dev_ethtool_ops;
> +	netdev->rtnl_link_ops = &internal_dev_link_ops;
>  	netdev->tx_queue_len = 0;
>  
>  	netdev->features = NETIF_F_LLTX | NETIF_F_SG | NETIF_F_FRAGLIST |
> @@ -248,3 +254,13 @@ struct vport *ovs_internal_dev_get_vport(struct net_device *netdev)
>  
>  	return internal_dev_priv(netdev)->vport;
>  }
> +
> +int ovs_internal_dev_rtnl_link_register(void)
> +{
> +	return rtnl_link_register(&internal_dev_link_ops);
> +}
> +
> +void ovs_internal_dev_rtnl_link_unregister(void)
> +{
> +	rtnl_link_unregister(&internal_dev_link_ops);
> +}
> diff --git a/net/openvswitch/vport-internal_dev.h b/net/openvswitch/vport-internal_dev.h
> index 9a7d30e..1b179a1 100644
> --- a/net/openvswitch/vport-internal_dev.h
> +++ b/net/openvswitch/vport-internal_dev.h
> @@ -24,5 +24,7 @@
>  
>  int ovs_is_internal_dev(const struct net_device *);
>  struct vport *ovs_internal_dev_get_vport(struct net_device *);
> +int ovs_internal_dev_rtnl_link_register(void);
> +void ovs_internal_dev_rtnl_link_unregister(void);
>  
>  #endif /* vport-internal_dev.h */

Re: [patch net-next 1/2] rtnetlink: allow to register ops without ops->setup set

[Jiri Pirko]

Wed, Jun 25, 2014 at 05:55:02PM CEST, ebiederm@xmission.com wrote:
>Jiri Pirko <jiri@resnulli.us> writes:
>
>> So far, it is assumed that ops->setup is filled up. But there might be
>> case that ops might make sense even without ->setup. In that case,
>> forbid to newlink and dellink.
>
>This patch does not handle all cases of dellink, and so you have created
>a way to oops the kernel.  One case that is not handled is
>default_device_exit_batch.

Thanks. Missed that.

>
>Further using !setup to prevent dellink does not make any kind of
>logical sense.  Which leads to a maintenance hazard.  Aka how can we
>further update this code without running into weird corner cases.

You are right. Changed this in next patch iteration.


>
>Further you have not given a description why anyone would want to have
>something that is almost completely unlike rtnl link operations
>implemented with the rtnl link operations.


Well the main reason is that this is consistent way of telling what kind
of netdevice or slave kind this is to userspace. I do not see any reason
to do it in some other way. We just would not use rtnllinkops to its full
potential in cases like this, which is I believe ok.

I will extend the patch desc.

Thanks for review Eric.

>
>
>> Signed-off-by: Jiri Pirko <jiri@resnulli.us>
>> ---
>>  net/core/rtnetlink.c | 5 ++++-
>>  1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
>> index 1063996..84affd7 100644
>> --- a/net/core/rtnetlink.c
>> +++ b/net/core/rtnetlink.c
>> @@ -1777,7 +1777,7 @@ static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh)
>>  		return -ENODEV;
>>  
>>  	ops = dev->rtnl_link_ops;
>> -	if (!ops)
>> +	if (!ops || !ops->setup)
>>  		return -EOPNOTSUPP;
>>  
>>  	ops->dellink(dev, &list_kill);
>> @@ -2038,6 +2038,9 @@ replay:
>>  			return -EOPNOTSUPP;
>>  		}
>>  
>> +		if (!ops->setup)
>> +			return -EOPNOTSUPP;
>> +
>>  		if (!ifname[0])
>>  			snprintf(ifname, IFNAMSIZ, "%s%%d", ops->kind);

Re: [patch net-next 2/2] openvswitch: introduce rtnl ops stub

[Jiri Pirko]

Wed, Jun 25, 2014 at 06:02:42PM CEST, ebiederm@xmission.com wrote:
>Jiri Pirko <jiri@resnulli.us> writes:
>
>> This stub now allows userspace to see IFLA_INFO_KIND for ovs master and
>> IFLA_INFO_SLAVE_KIND for slave.
>
>I am puzzled why you don't implement full rtnl_link_operations support.

openvswitch does not need that at the moment (most probably it never
will). Creation and deletion is handled over separate genl channel.

>
>If all you want is to report which kind of driver you have I suspect
>implementing ethtool_ops.get_drvinfo is a much better fit.

That is maybe partly true but that would not be consistent with bond, team,
bridge masters and slaves which benefit ops->kind to expose the type
into userspace.

>
>Eric
>
>> Signed-off-by: Jiri Pirko <jiri@resnulli.us>
>> ---
>>  net/openvswitch/datapath.c           |  9 ++++++++-
>>  net/openvswitch/vport-internal_dev.c | 16 ++++++++++++++++
>>  net/openvswitch/vport-internal_dev.h |  2 ++
>>  3 files changed, 26 insertions(+), 1 deletion(-)
>>
>> diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
>> index 0d407bc..fe95b6c 100644
>> --- a/net/openvswitch/datapath.c
>> +++ b/net/openvswitch/datapath.c
>> @@ -2054,10 +2054,14 @@ static int __init dp_init(void)
>>  
>>  	pr_info("Open vSwitch switching datapath\n");
>>  
>> -	err = ovs_flow_init();
>> +	err = ovs_internal_dev_rtnl_link_register();
>>  	if (err)
>>  		goto error;
>>  
>> +	err = ovs_flow_init();
>> +	if (err)
>> +		goto error_unreg_rtnl_link;
>> +
>>  	err = ovs_vport_init();
>>  	if (err)
>>  		goto error_flow_exit;
>> @@ -2084,6 +2088,8 @@ error_vport_exit:
>>  	ovs_vport_exit();
>>  error_flow_exit:
>>  	ovs_flow_exit();
>> +error_unreg_rtnl_link:
>> +	ovs_internal_dev_rtnl_link_unregister();
>>  error:
>>  	return err;
>>  }
>> @@ -2096,6 +2102,7 @@ static void dp_cleanup(void)
>>  	rcu_barrier();
>>  	ovs_vport_exit();
>>  	ovs_flow_exit();
>> +	ovs_internal_dev_rtnl_link_unregister();
>>  }
>>  
>>  module_init(dp_init);
>> diff --git a/net/openvswitch/vport-internal_dev.c b/net/openvswitch/vport-internal_dev.c
>> index 789af92..295471a 100644
>> --- a/net/openvswitch/vport-internal_dev.c
>> +++ b/net/openvswitch/vport-internal_dev.c
>> @@ -26,6 +26,7 @@
>>  
>>  #include <net/dst.h>
>>  #include <net/xfrm.h>
>> +#include <net/rtnetlink.h>
>>  
>>  #include "datapath.h"
>>  #include "vport-internal_dev.h"
>> @@ -121,6 +122,10 @@ static const struct net_device_ops internal_dev_netdev_ops = {
>>  	.ndo_get_stats64 = internal_dev_get_stats,
>>  };
>>  
>> +static struct rtnl_link_ops internal_dev_link_ops __read_mostly = {
>> +	.kind = "openvswitch",
>> +};
>> +
>>  static void do_setup(struct net_device *netdev)
>>  {
>>  	ether_setup(netdev);
>> @@ -131,6 +136,7 @@ static void do_setup(struct net_device *netdev)
>>  	netdev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
>>  	netdev->destructor = internal_dev_destructor;
>>  	netdev->ethtool_ops = &internal_dev_ethtool_ops;
>> +	netdev->rtnl_link_ops = &internal_dev_link_ops;
>>  	netdev->tx_queue_len = 0;
>>  
>>  	netdev->features = NETIF_F_LLTX | NETIF_F_SG | NETIF_F_FRAGLIST |
>> @@ -248,3 +254,13 @@ struct vport *ovs_internal_dev_get_vport(struct net_device *netdev)
>>  
>>  	return internal_dev_priv(netdev)->vport;
>>  }
>> +
>> +int ovs_internal_dev_rtnl_link_register(void)
>> +{
>> +	return rtnl_link_register(&internal_dev_link_ops);
>> +}
>> +
>> +void ovs_internal_dev_rtnl_link_unregister(void)
>> +{
>> +	rtnl_link_unregister(&internal_dev_link_ops);
>> +}
>> diff --git a/net/openvswitch/vport-internal_dev.h b/net/openvswitch/vport-internal_dev.h
>> index 9a7d30e..1b179a1 100644
>> --- a/net/openvswitch/vport-internal_dev.h
>> +++ b/net/openvswitch/vport-internal_dev.h
>> @@ -24,5 +24,7 @@
>>  
>>  int ovs_is_internal_dev(const struct net_device *);
>>  struct vport *ovs_internal_dev_get_vport(struct net_device *);
>> +int ovs_internal_dev_rtnl_link_register(void);
>> +void ovs_internal_dev_rtnl_link_unregister(void);
>>  
>>  #endif /* vport-internal_dev.h */

Re: [patch net-next 2/2] openvswitch: introduce rtnl ops stub

[Eric W. Biederman]

Jiri Pirko <jiri@resnulli.us> writes:

> Wed, Jun 25, 2014 at 06:02:42PM CEST, ebiederm@xmission.com wrote:
>>Jiri Pirko <jiri@resnulli.us> writes:
>>
>>> This stub now allows userspace to see IFLA_INFO_KIND for ovs master and
>>> IFLA_INFO_SLAVE_KIND for slave.
>>
>>I am puzzled why you don't implement full rtnl_link_operations support.
>
> openvswitch does not need that at the moment (most probably it never
> will). Creation and deletion is handled over separate genl channel.
>
>>
>>If all you want is to report which kind of driver you have I suspect
>>implementing ethtool_ops.get_drvinfo is a much better fit.
>
> That is maybe partly true but that would not be consistent with bond, team,
> bridge masters and slaves which benefit ops->kind to expose the type
> into userspace.

So instead of using the mechanism that is supported by most of the
network drivers in the tree you are instead relying on a mechanism
that only works for a handful of software defined network devices.

I really think exposing a kind at this point is lying to user space
as having a kind implies that the netlink messages behind "ip link add"
and "ip link del" work.

Further I have seen nothing in what you are proposing that addresses
that absolute horrible maintenance consequences of your patch.

Eric

Re: [patch net-next 2/2] openvswitch: introduce rtnl ops stub

[Jiri Pirko]

Wed, Jun 25, 2014 at 07:13:09PM CEST, ebiederm@xmission.com wrote:
>Jiri Pirko <jiri@resnulli.us> writes:
>
>> Wed, Jun 25, 2014 at 06:02:42PM CEST, ebiederm@xmission.com wrote:
>>>Jiri Pirko <jiri@resnulli.us> writes:
>>>
>>>> This stub now allows userspace to see IFLA_INFO_KIND for ovs master and
>>>> IFLA_INFO_SLAVE_KIND for slave.
>>>
>>>I am puzzled why you don't implement full rtnl_link_operations support.
>>
>> openvswitch does not need that at the moment (most probably it never
>> will). Creation and deletion is handled over separate genl channel.
>>
>>>
>>>If all you want is to report which kind of driver you have I suspect
>>>implementing ethtool_ops.get_drvinfo is a much better fit.
>>
>> That is maybe partly true but that would not be consistent with bond, team,
>> bridge masters and slaves which benefit ops->kind to expose the type
>> into userspace.
>
>So instead of using the mechanism that is supported by most of the
>network drivers in the tree you are instead relying on a mechanism
>that only works for a handful of software defined network devices.

As I said, I just want openvswitch to be similar in this with
bridge/bond/team. ops->kind is there, its exposed to userspace, I don't
see any harm adding one another code which benefits that.

Note that this also allows to see slave kind.

>
>I really think exposing a kind at this point is lying to user space
>as having a kind implies that the netlink messages behind "ip link add"
>and "ip link del" work.

Proper -EOPNOTSUPP is returned. And is is the same as if !ops. The
behavior is not changed.

>
>Further I have seen nothing in what you are proposing that addresses
>that absolute horrible maintenance consequences of your patch.

I don't understand what maintenance consequences you have on mind. Would
you please exmplain? Thanks.

>
>Eric