[Devel] Re: [PATCH 1/12] L2 network namespace: current network namespace operations

[Eric W. Biederman]

Dmitry Mishin <dim at openvz.org> writes:

> Added functions and macros required to operate with current network namespaces.
> They are required in order to switch network namespace for incoming packets and
> to not extend current network interface by addtiotional network namespace argue.
>
> Signed-off-by: Dmitry Mishin <dim at openvz.org>
>
> -#else
> +#define current_net_ns		(current->nsproxy->net_ns)
> +#else /* CONFIG_NET_NS */
>  
>  #define INIT_NET_NS(net_ns)
>  
> @@ -57,6 +78,22 @@ static inline int copy_net_ns(int flags,
>  static inline void put_net_ns(struct net_namespace *ns)
>  {
>  }
> -#endif
> +
> +#define current_net_ns			NULL

> +#endif /* !CONFIG_NET_NS */

Ouch!  NULL is not a good default.

Can we please pick an idiom for referencing global network stack
variables that works if we are compiled in or not.  At least if
we are going to offer the option.

That way we can merge the changes for looking up all of the globals
before merging the network namespace support.

Doing it this way seems to imply we will need context support to
implement this.

My initial suggestion is to base the work on the per cpu variable
support.

Using __get_net_var(variable).  To reference the global variable.
And the variables marked as __per_net in their declaration so
we know the variables are per network namespace.

This allows us to handle ipv6 and other modules that only have their
variables present when they are loaded the same way per cpu variables
are treated.  And it ensures that the form used when everything is

Eric
_______________________________________________
Containers mailing list
Containers at lists.osdl.org
https://lists.osdl.org/mailman/listinfo/containers