nsdo

nsdo (network namespace do) is a simple C program that runs a command inside a given Linux network namespace.

Effectively, it simplifies:

$ sudo ip netns exec myns sudo -u $USER myprogram

to

$ nsdo myns myprogram

Thanks to magic of the setuid bit, it initially has root privileges, which allows it to change its own network namespace, setuid() to the user who ran the command, and then exec() the requested command.

installation

If you're on Arch, you can build my AUR package.

Otherwise:

$ make
# make install

To change the default installation directory of /usr/local, set PREFIX to something else when you call make install.

openvpn example

I wrote this program because I run some applications under a VPN (e.g., clients for peer-to-peer protocols) and leave others untouched (like a game client).

For more details, see my blog post on the subject.

license

MIT/X11.

manpage

nsdo(1)               General Commands Manual              nsdo(1)

NAME
       nsdo - run a command in a network namespace

SYNOPSIS
       nsdo namespace command [args ...]

       nsdo { --version | -V }

DESCRIPTION
       Execute  command  as the current user/group in namespace, a
       Linux network namespace  set  up  with  iproute2  (see  ip-
       netns(8)).

       By   default,   iproute2   places   network  namespaces  in
       /var/run/netns/,  so  nsdo  searces  for  namespaces  there
       (including  namespace).   To  prevent  command  from easily
       escaping the namespace 'jail,' nsdo will exit if  the  cur‐
       rent namespace exists in that directory.  Consequently, you
       can not nest instances of nsdo.

OPTIONS
       --version, -V
              Instead of running a command, print  nsdo's  version
              and exit.

SEE ALSO
       ip(8), ip-netns(8), namespaces(7), nsenter(1)

                            2016-01-23                     nsdo(1)