Re: [PATCH V2 0/1] ipv4: net namespace does not inherit network configurations

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 21 Aug 2014 10:32:00 +0800
Zhu Yanjun <zyjzyj2000@gmail.com> wrote:

> V2: Following the advice from Cong Wang, I submit a patch as normal.
> 
> Hi,all
> 
> I did a test on kernel3.16 rc6:
> 
> root@qemu1:~# echo 1 > /proc/sys/net/ipv6/conf/all/forwarding
> root@qemu1:~# echo 1 > /proc/sys/net/ipv4/conf/all/forwarding
> root@qemu1:~# ip netns list
> root@qemu1:~# ip netns add fib1
> root@qemu1:~# ip netns exec fib1 bash
> root@qemu1:~# cat /proc/sys/net/ipv6/conf/all/forwarding
> 0
> root@qemu1:~# cat /proc/sys/net/ipv4/conf/all/forwarding
> 1
> 
> The behavior of ipv4 and ipv6 is very inconsistent. I checked
> the kernel source code. I found that from this patch
> [ipv6: fix bad free of addrconf_init_net], the above difference
> appeared.
> 
> Since a net namespace is independent to another. That is, there
> is no any relationship between the net namespaces. So the behavior
> of ipv4 is not correct.
> 
> Based on this patch [ipv6: fix bad free of addrconf_init_net], I made
> a new patch to fix this problem on ipv4.
> 
> Any reply is appreciated. 
> 
> Zhu Yanjun (1):
>   ipv4: net namespace does not inherit network configurations
> 
>  net/ipv4/devinet.c | 29 ++++++++++++-----------------
>  1 file changed, 12 insertions(+), 17 deletions(-)
> 

This a semantic change to network namespaces and therefore is
likely to break existing applications using network namespaces.