Moving interfaces to the outer namespace

[jimfunk]

I'm trying to get interfaces that I have moved into a namespace back out into the main namespace. However, none of the obvious methods appear to work. I've tried setting net_ns_pid and net_ns_fd and both fail in different way.

When I tried net_ns_pid, it would wait a while and then half-work:

Traceback (most recent call last):
  File "./nstest.py", line 21, in <module>
    interface.net_ns_pid = os.getpid()
  File "/usr/lib/python3.5/site-packages/pyroute2/ipdb/transactional.py", line 194, in __exit__
    self.commit()
  File "/usr/lib/python3.5/site-packages/pyroute2/ipdb/interface.py", line 905, in commit
    raise error
  File "/usr/lib/python3.5/site-packages/pyroute2/ipdb/interface.py", line 745, in commit
    transaction.wait_all_targets()
  File "/usr/lib/python3.5/site-packages/pyroute2/ipdb/transactional.py", line 468, in wait_all_targets
    raise CommitException('target %s is not set' % key)
pyroute2.ipdb.exceptions.CommitException: target net_ns_pid is not set

The really strange thing here is that the interface exists in both the outer and inner namespaces at this point. I didn't think that was even possible:

# ip link show fooint
73: fooint: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether 12:51:fa:28:2f:2e brd ff:ff:ff:ff:ff:ff
# ip netns exec foo ip link show fooint
7: fooint: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether 12:51:fa:28:2f:2e brd ff:ff:ff:ff:ff:ff

With net_ns_fd, it doesn't work at all:

Traceback (most recent call last):
  File "./nstest.py", line 22, in <module>
    interface.net_ns_fd = outer_ns_fd
  File "/usr/lib/python3.5/site-packages/pyroute2/ipdb/transactional.py", line 194, in __exit__
    self.commit()
  File "/usr/lib/python3.5/site-packages/pyroute2/ipdb/interface.py", line 905, in commit
    raise error
  File "/usr/lib/python3.5/site-packages/pyroute2/ipdb/interface.py", line 727, in commit
    run(nl.link, 'set', **request)
  File "/usr/lib/python3.5/site-packages/pyroute2/ipdb/interface.py", line 459, in _run
    raise error
  File "/usr/lib/python3.5/site-packages/pyroute2/ipdb/interface.py", line 454, in _run
    return cmd(*argv, **kwarg)
  File "/usr/lib/python3.5/site-packages/pyroute2/iproute.py", line 1239, in link
    msg_flags=msg_flags)
  File "/usr/lib/python3.5/site-packages/pyroute2/netlink/nlsocket.py", line 791, in nlm_request
    return do_try()
  File "/usr/lib/python3.5/site-packages/pyroute2/netlink/nlsocket.py", line 770, in do_try
    ret = self.get(msg_seq=msg_seq, terminate=terminate)
  File "/usr/lib/python3.5/site-packages/pyroute2/netlink/nlsocket.py", line 638, in get
    raise msg['header']['error']
pyroute2.netlink.exceptions.NetlinkError: (9, 'Bad file descriptor')

This is the script I'm using to test:

#!/usr/bin/env python3
import os
from pyroute2 import NetNS, IPDB


outer = IPDB()
netns = NetNS('foo')
inner = IPDB(netns)
outer_ns_fd = os.open('/proc/%s/ns/net' % os.getpid(), os.O_RDONLY)
#outer_ns_fd = os.open('/var/run/netns/foo', os.O_RDONLY)


for ipdb in (outer, inner):
    if 'fooint' in ipdb.interfaces:
        with ipdb.interfaces['fooint'] as interface:
            interface.remove()

inner.create(ifname='fooint', kind='dummy').commit()

with inner.interfaces['fooint'] as interface:
    #interface.net_ns_pid = os.getpid()
    interface.net_ns_fd = outer_ns_fd

assert 'fooint' not in inner.interfaces
assert 'fooint' in outer.interfaces

[svinota]

I didn't think that was even possible

Ahhaha, me neither :)))) Thanks for the report, and give me some time to investigate :)

[svinota]

Pls, write also you kernel and pyroute2 versions. Thanks!

[svinota]

The net_ns_pid in IPDB is fixed, pls try it.

[jimfunk]

Yup. This works perfectly.

Thanks!

[svinota]

Cool. So I close the issue.