PIM-SM namespace changes

PIM-SM namespace changes

[David Miller]

Some bugs to fix before I can apply these Tom.

For one thing, in the IPV4 patch:

 	setup_timer(&ipmr_expire_timer, ipmr_expire_process, 0);
 	err = register_netdevice_notifier(&ip_mr_notifier);
+#ifdef CONFIG_IP_PIMSM_V2
+	if (inet_add_protocol(&pim_protocol, IPPROTO_PIM) < 0) {
+		printk(KERN_ERR "ip_mr_init: can't add PIM protocol\n");
+		err = -EAGAIN;
+	}
+#endif
 	if (err)
 		goto reg_notif_fail;

This adds the protocol even if the notifier registry fails.

It also leaves the notifier registered if the protocol add fails.

Also we need to seriously discuss how now we unconditionally
register the PIM protocols.  Before we had a policy of only
doing so conditionally, and that's a change that needs to
be carefully considered and discussed.

Re: PIM-SM namespace changes

[Tom Goff]

> Some bugs to fix before I can apply these Tom.
...
> Also we need to seriously discuss how now we unconditionally
> register the PIM protocols.  Before we had a policy of only
> doing so conditionally, and that's a change that needs to
> be carefully considered and discussed.

Thanks for the feedback, I think the patch below includes proper error
handling.

For protocol registration I see three basic approaches for using PIM
with namespaces:

  - unconditionally add PIM when multicast routing is initialized
    (maybe only ifdef CONFIG_NET_NS, otherwise preserve the current
    behavior)

  - keep a count of the number of namespaces that have enabled PIM and
    add/delete PIM when transitioning from/to zero

  - make all or some protocol registration per network namespace

There are obviously tradeoffs and I would appreciate any
comments/suggestions on alternatives that allow namespace use of
dynamically enabled protocols.

  Tom


PIM-SM namespace changes

IPv4:
  - make PIM register vifs netns local
  - set the netns when a PIM register vif is created
  - make PIM available in all network namespaces (if CONFIG_IP_PIMSM_V2)
    by adding the protocol handler when multicast routing is initialized

IPv6:
  - make PIM register vifs netns local
  - make PIM available in all network namespaces (if CONFIG_IPV6_PIMSM_V2)
    by adding the protocol handler when multicast routing is initialized

Signed-off-by: Tom Goff <thomas.goff@boeing.com>
---
 net/ipv4/ipmr.c  |   29 +++++++++++++++++------------
 net/ipv6/ip6mr.c |   20 ++++++++++++--------
 2 files changed, 29 insertions(+), 20 deletions(-)

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 13e9dd3..0f34e25 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -226,9 +226,10 @@ static void reg_vif_setup(struct net_device *dev)
 	dev->flags		= IFF_NOARP;
 	dev->netdev_ops		= &reg_vif_netdev_ops,
 	dev->destructor		= free_netdev;
+	dev->features		|= NETIF_F_NETNS_LOCAL;
 }
 
-static struct net_device *ipmr_reg_vif(void)
+static struct net_device *ipmr_reg_vif(struct net *net)
 {
 	struct net_device *dev;
 	struct in_device *in_dev;
@@ -238,6 +239,8 @@ static struct net_device *ipmr_reg_vif(void)
 	if (dev == NULL)
 		return NULL;
 
+	dev_net_set(dev, net);
+
 	if (register_netdevice(dev)) {
 		free_netdev(dev);
 		return NULL;
@@ -448,7 +451,7 @@ static int vif_add(struct net *net, struct vifctl *vifc, int mrtsock)
 		 */
 		if (net->ipv4.mroute_reg_vif_num >= 0)
 			return -EADDRINUSE;
-		dev = ipmr_reg_vif();
+		dev = ipmr_reg_vif(net);
 		if (!dev)
 			return -ENOBUFS;
 		err = dev_set_allmulti(dev, 1);
@@ -1031,16 +1034,6 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, int
 		if (v != net->ipv4.mroute_do_pim) {
 			net->ipv4.mroute_do_pim = v;
 			net->ipv4.mroute_do_assert = v;
-#ifdef CONFIG_IP_PIMSM_V2
-			if (net->ipv4.mroute_do_pim)
-				ret = inet_add_protocol(&pim_protocol,
-							IPPROTO_PIM);
-			else
-				ret = inet_del_protocol(&pim_protocol,
-							IPPROTO_PIM);
-			if (ret < 0)
-				ret = -EAGAIN;
-#endif
 		}
 		rtnl_unlock();
 		return ret;
@@ -1955,6 +1948,7 @@ static const struct file_operations ipmr_mfc_fops = {
 #ifdef CONFIG_IP_PIMSM_V2
 static struct net_protocol pim_protocol = {
 	.handler	=	pim_rcv,
+	.netns_ok	=	1,
 };
 #endif
 
@@ -2041,8 +2035,19 @@ int __init ip_mr_init(void)
 	err = register_netdevice_notifier(&ip_mr_notifier);
 	if (err)
 		goto reg_notif_fail;
+#ifdef CONFIG_IP_PIMSM_V2
+	if (inet_add_protocol(&pim_protocol, IPPROTO_PIM) < 0) {
+		printk(KERN_ERR "ip_mr_init: can't add PIM protocol\n");
+		err = -EAGAIN;
+		goto add_proto_fail;
+	}
+#endif
 	return 0;
 
+#ifdef CONFIG_IP_PIMSM_V2
+add_proto_fail:
+	unregister_netdevice_notifier(&ip_mr_notifier);
+#endif
 reg_notif_fail:
 	del_timer(&ipmr_expire_timer);
 	unregister_pernet_subsys(&ipmr_net_ops);
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 228be55..6055c58 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -442,6 +442,7 @@ static void reg_vif_setup(struct net_device *dev)
 	dev->flags		= IFF_NOARP;
 	dev->netdev_ops		= &reg_vif_netdev_ops;
 	dev->destructor		= free_netdev;
+	dev->features		|= NETIF_F_NETNS_LOCAL;
 }
 
 static struct net_device *ip6mr_reg_vif(struct net *net)
@@ -1078,7 +1079,18 @@ int __init ip6_mr_init(void)
 	err = register_netdevice_notifier(&ip6_mr_notifier);
 	if (err)
 		goto reg_notif_fail;
+#ifdef CONFIG_IPV6_PIMSM_V2
+	if (inet6_add_protocol(&pim6_protocol, IPPROTO_PIM) < 0) {
+		printk(KERN_ERR "ip6_mr_init: can't add PIM protocol\n");
+		err = -EAGAIN;
+		goto add_proto_fail;
+	}
+#endif
 	return 0;
+#ifdef CONFIG_IPV6_PIMSM_V2
+add_proto_fail:
+	unregister_netdevice_notifier(&ip6_mr_notifier);
+#endif
 reg_notif_fail:
 	del_timer(&ipmr_expire_timer);
 	unregister_pernet_subsys(&ip6mr_net_ops);
@@ -1364,14 +1376,6 @@ int ip6_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, int
 		if (v != net->ipv6.mroute_do_pim) {
 			net->ipv6.mroute_do_pim = v;
 			net->ipv6.mroute_do_assert = v;
-			if (net->ipv6.mroute_do_pim)
-				ret = inet6_add_protocol(&pim6_protocol,
-							 IPPROTO_PIM);
-			else
-				ret = inet6_del_protocol(&pim6_protocol,
-							 IPPROTO_PIM);
-			if (ret < 0)
-				ret = -EAGAIN;
 		}
 		rtnl_unlock();
 		return ret;
-- 
1.6.0.6

Re: PIM-SM namespace changes

[Tom Goff]

On Tue, May 19, 2009 at 05:43:44PM -0700, Tom Goff wrote:
> > Some bugs to fix before I can apply these Tom.
> ...
> > Also we need to seriously discuss how now we unconditionally
> > register the PIM protocols.  Before we had a policy of only
> > doing so conditionally, and that's a change that needs to
> > be carefully considered and discussed.
> 
> Thanks for the feedback, I think the patch below includes proper error
> handling.
> 
> For protocol registration I see three basic approaches for using PIM
> with namespaces:
> 
>   - unconditionally add PIM when multicast routing is initialized
>     (maybe only ifdef CONFIG_NET_NS, otherwise preserve the current
>     behavior)
> 
>   - keep a count of the number of namespaces that have enabled PIM and
>     add/delete PIM when transitioning from/to zero
> 
>   - make all or some protocol registration per network namespace
> 
> There are obviously tradeoffs and I would appreciate any
> comments/suggestions on alternatives that allow namespace use of
> dynamically enabled protocols.
> 
[patch omitted]

Any further thoughts on handling PIM/namespace interaction?

  Tom

Re: PIM-SM namespace changes

[David Miller]

From: Tom Goff <thomas.goff@boeing.com>
Date: Mon, 1 Jun 2009 13:28:34 -0700

> Any further thoughts on handling PIM/namespace interaction?

It's in my backlog.

Mindless work such as reviewing bug fixes and "easy" patches takes up
all of my time most days... leaving no time for patches and questions
that require real in-depth thinking and study on my part.

Re: PIM-SM namespace changes

[David Miller]

From: Tom Goff <thomas.goff@boeing.com>
Date: Tue, 19 May 2009 17:43:44 -0700

> For protocol registration I see three basic approaches for using PIM
> with namespaces:
> 
>   - unconditionally add PIM when multicast routing is initialized
>     (maybe only ifdef CONFIG_NET_NS, otherwise preserve the current
>     behavior)
> 
>   - keep a count of the number of namespaces that have enabled PIM and
>     add/delete PIM when transitioning from/to zero
> 
>   - make all or some protocol registration per network namespace
> 
> There are obviously tradeoffs and I would appreciate any
> comments/suggestions on alternatives that allow namespace use of
> dynamically enabled protocols.

Ok, I'm willing to accept your current approach for now, let's
see what falls out of this.  Patch applied, thanks.

Doing the enabling per-namespace is complexity for an unknown
gain.  I don't even know what the benefit could be for how we
behaved previously.

Anyone know?

Re: PIM-SM namespace changes

[Pavel Emelyanov]

David Miller wrote:
> From: Tom Goff <thomas.goff@boeing.com>
> Date: Tue, 19 May 2009 17:43:44 -0700
> 
>> For protocol registration I see three basic approaches for using PIM
>> with namespaces:
>>
>>   - unconditionally add PIM when multicast routing is initialized
>>     (maybe only ifdef CONFIG_NET_NS, otherwise preserve the current
>>     behavior)
>>
>>   - keep a count of the number of namespaces that have enabled PIM and
>>     add/delete PIM when transitioning from/to zero
>>
>>   - make all or some protocol registration per network namespace
>>
>> There are obviously tradeoffs and I would appreciate any
>> comments/suggestions on alternatives that allow namespace use of
>> dynamically enabled protocols.
> 
> Ok, I'm willing to accept your current approach for now, let's
> see what falls out of this.  Patch applied, thanks.
> 
> Doing the enabling per-namespace is complexity for an unknown
> gain.  I don't even know what the benefit could be for how we
> behaved previously.
> 
> Anyone know?

Well, maybe I do :)

I haven't thought much about per-namespace protocols, but I think, that
it makes sense to enable/disable at least virtual devices (tunnels and
vlans currently) per-namespace.

Not every namespace really needs this big amount of functionality and
saving sizeof(struct net_device) + private - the fallback devices each
tunnel creates, and this is somewhat around 4Kb each - sounds good.

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