[PATCH net-next] net: llc: remove init_net check

[PATCH net-next] net: llc: remove init_net check

[Alexander Aring]

Commit e730c15519d09 ("[NET]: Make packet reception network namespace
safe") added several init_net compares to protocols with unknown
net namespace support. The idea was as users started using the different
protocols they would test and enable them.
In our use-case we generate STP enabled Linux bridges in different
namespaces. The bridges are connected via veth interfaces.
This patch makes STP work in such a setup.

Signed-off-by: Alexander Aring <aring@mojatatu.com>
---
 net/llc/llc_input.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/net/llc/llc_input.c b/net/llc/llc_input.c
index 82cb93f66b9b..09b530d90610 100644
--- a/net/llc/llc_input.c
+++ b/net/llc/llc_input.c
@@ -14,7 +14,6 @@
 #include <linux/netdevice.h>
 #include <linux/slab.h>
 #include <linux/export.h>
-#include <net/net_namespace.h>
 #include <net/llc.h>
 #include <net/llc_pdu.h>
 #include <net/llc_sap.h>
@@ -162,9 +161,6 @@ int llc_rcv(struct sk_buff *skb, struct net_device *dev,
 	void (*sta_handler)(struct sk_buff *skb);
 	void (*sap_handler)(struct llc_sap *sap, struct sk_buff *skb);
 
-	if (!net_eq(dev_net(dev), &init_net))
-		goto drop;
-
 	/*
 	 * When the interface is in promisc. mode, drop all the crap that it
 	 * receives, do not try to analyse it.
-- 
2.11.0

Re: [PATCH net-next] net: llc: remove init_net check

[Eric Dumazet]

On Thu, 2017-11-30 at 14:45 -0500, Alexander Aring wrote:
> Commit e730c15519d09 ("[NET]: Make packet reception network namespace
> safe") added several init_net compares to protocols with unknown
> net namespace support. The idea was as users started using the
> different
> protocols they would test and enable them.
> In our use-case we generate STP enabled Linux bridges in different
> namespaces. The bridges are connected via veth interfaces.
> This patch makes STP work in such a setup.
> 
> Signed-off-by: Alexander Aring <aring@mojatatu.com>
> ---
>  net/llc/llc_input.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/net/llc/llc_input.c b/net/llc/llc_input.c
> index 82cb93f66b9b..09b530d90610 100644
> --- a/net/llc/llc_input.c
> +++ b/net/llc/llc_input.c
> @@ -14,7 +14,6 @@
>  #include <linux/netdevice.h>
>  #include <linux/slab.h>
>  #include <linux/export.h>
> -#include <net/net_namespace.h>
>  #include <net/llc.h>
>  #include <net/llc_pdu.h>
>  #include <net/llc_sap.h>
> @@ -162,9 +161,6 @@ int llc_rcv(struct sk_buff *skb, struct
> net_device *dev,
>  	void (*sta_handler)(struct sk_buff *skb);
>  	void (*sap_handler)(struct llc_sap *sap, struct sk_buff
> *skb);
>  
> -	if (!net_eq(dev_net(dev), &init_net))
> -		goto drop;
> -
>  	/*
>  	 * When the interface is in promisc. mode, drop all the crap
> that it
>  	 * receives, do not try to analyse it.


Well, we use different netns for isolation.

You need more changes than simply removing this check, I guess.

__llc_sap_find() would need a per netns list, or proper netns checks.

Re: [PATCH net-next] net: llc: remove init_net check

[Alexander Aring]

Hi,

On Thu, Nov 30, 2017 at 3:12 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
>
...
>
>
> Well, we use different netns for isolation.
>
> You need more changes than simply removing this check, I guess.
>
> __llc_sap_find() would need a per netns list, or proper netns checks.
>

I looked deeper into this and try to move the list from global
resource to net struct and use per netns init... it's just a very big
task and I try to do my best there...
Also I figured out that the bridge code use a lot of global resources
which should also be per netns as well and I am worried that you can
actually move bridges to different namespaces. :-/

Just a status update - when I have time I try to do that... just need
time and it's not simple to do this change in llc.

- Alex