| Dir : /proc/self/root/opt/saltstack/salt/extras-3.10/pyroute2/nslink/ |
| Server: Linux ngx353.inmotionhosting.com 4.18.0-553.22.1.lve.1.el8.x86_64 #1 SMP Tue Oct 8 15:52:54 UTC 2024 x86_64 IP: 209.182.202.254 |
| Dir : //proc/self/root/opt/saltstack/salt/extras-3.10/pyroute2/nslink/nslink.py |
'''
NetNS objects
=============
A NetNS object is IPRoute-like. It runs in the main network
namespace, but also creates a proxy process running in
the required netns. All the netlink requests are done via
that proxy process.
NetNS supports standard IPRoute API, so can be used instead
of IPRoute, e.g., in IPDB::
# start the main network settings database:
ipdb_main = IPDB()
# start the same for a netns:
ipdb_test = IPDB(nl=NetNS('test'))
# create VETH
ipdb_main.create(ifname='v0p0', kind='veth', peer='v0p1').commit()
# move peer VETH into the netns
with ipdb_main.interfaces.v0p1 as veth:
veth.net_ns_fd = 'test'
# please keep in mind, that netns move clears all the settings
# on a VETH interface pair, so one should run netns assignment
# as a separate operation only
# assign addresses
# please notice, that `v0p1` is already in the `test` netns,
# so should be accessed via `ipdb_test`
with ipdb_main.interfaces.v0p0 as veth:
veth.add_ip('172.16.200.1/24')
veth.up()
with ipdb_test.interfaces.v0p1 as veth:
veth.add_ip('172.16.200.2/24')
veth.up()
Please review also the test code, under `tests/test_netns.py` for
more examples.
By default, NetNS creates requested netns, if it doesn't exist,
or uses existing one. To control this behaviour, one can use flags
as for `open(2)` system call::
# create a new netns or fail, if it already exists
netns = NetNS('test', flags=os.O_CREAT | os.O_EXCL)
# create a new netns or use existing one
netns = NetNS('test', flags=os.O_CREAT)
# the same as above, the default behaviour
netns = NetNS('test')
To remove a network namespace::
from pyroute2 import NetNS
netns = NetNS('test')
netns.close()
netns.remove()
One should stop it first with `close()`, and only after that
run `remove()`.
'''
import atexit
import errno
import logging
import os
from functools import partial
from pyroute2.iproute import RTNL_API
from pyroute2.netlink.rtnl import RTMGRP_DEFAULTS
from pyroute2.netlink.rtnl.iprsocket import MarshalRtnl
from pyroute2.netns import remove, setns
from ..remote.transport import RemoteSocket, Server, Transport
log = logging.getLogger(__name__)
class FD(object):
def __init__(self, fd):
self.fd = fd
for name in ('read', 'write', 'close'):
setattr(self, name, partial(getattr(os, name), self.fd))
def fileno(self):
return self.fd
def flush(self):
return None
class NetNS(RTNL_API, RemoteSocket):
'''
NetNS is the IPRoute API with network namespace support.
**Why not IPRoute?**
The task to run netlink commands in some network namespace, being in
another network namespace, requires the architecture, that differs
too much from a simple Netlink socket.
NetNS starts a proxy process in a network namespace and uses
`multiprocessing` communication channels between the main and the proxy
processes to route all `recv()` and `sendto()` requests/responses.
**Any specific API calls?**
Nope. `NetNS` supports all the same, that `IPRoute` does, in the same
way. It provides full `socket`-compatible API and can be used in
poll/select as well.
The only difference is the `close()` call. In the case of `NetNS` it
is **mandatory** to close the socket before exit.
'''
def __init__(
self,
netns,
flags=os.O_CREAT,
target=None,
libc=None,
groups=RTMGRP_DEFAULTS,
):
self.netns = netns
self.flags = flags
target = target or netns
trnsp_in, self.remote_trnsp_out = [Transport(FD(x)) for x in os.pipe()]
self.remote_trnsp_in, trnsp_out = [Transport(FD(x)) for x in os.pipe()]
self.child = os.fork()
if self.child == 0:
# child process
trnsp_in.close()
trnsp_out.close()
trnsp_in.file_obj.close()
trnsp_out.file_obj.close()
try:
setns(self.netns, self.flags, libc=libc)
except OSError as e:
(self.remote_trnsp_out.send({'stage': 'init', 'error': e}))
os._exit(e.errno)
except Exception as e:
(
self.remote_trnsp_out.send(
{
'stage': 'init',
'error': OSError(errno.ECOMM, str(e), self.netns),
}
)
)
os._exit(255)
try:
Server(
self.remote_trnsp_in,
self.remote_trnsp_out,
target=target,
groups=groups,
)
finally:
os._exit(0)
try:
self.remote_trnsp_in.close()
self.remote_trnsp_out.close()
super(NetNS, self).__init__(trnsp_in, trnsp_out, groups=groups)
self.target = target
except Exception:
self.close()
raise
atexit.register(self.close)
self.marshal = MarshalRtnl()
def clone(self):
return type(self)(self.netns, self.flags)
def _cleanup_atexit(self):
if hasattr(atexit, 'unregister'):
atexit.unregister(self.close)
else:
try:
atexit._exithandlers.remove((self.close, (), {}))
except ValueError:
pass
def close(self, code=errno.ECONNRESET):
self._cleanup_atexit()
try:
super(NetNS, self).close(code=code)
except:
# something went wrong, force server shutdown
try:
self.trnsp_out.send({'stage': 'shutdown'})
except Exception:
pass
log.error('forced shutdown procedure, clean up netns manually')
def open_file(self, path):
'''Proxy the open_file method if we are the parent.'''
if self.child != 0:
return self.proxy('open_file', path)
return super(NetNS, self).open_file(path)
def close_file(self, fd):
'''Proxy the close_file method if we are the parent.'''
if self.child != 0:
return self.proxy('close_file', fd)
return super(NetNS, self).close_file(fd)
def get_pid(self):
'''Proxy the get_pid method if we are the parent.'''
if self.child != 0:
return self.proxy('get_pid')
return super(NetNS, self).get_pid()
def post_init(self):
pass
def remove(self):
'''
Try to remove this network namespace from the system.
'''
remove(self.netns)