Added VpnProtocol.

sjrpc/core/protocols/__init__.py

@@ -82,5 +82,6 @@ class Protocol(object):
 
 from sjrpc.core.protocols.rpc import RpcProtocol
 from sjrpc.core.protocols.tunnel import TunnelProtocol
+from sjrpc.core.protocols.vpn import VpnProtocol
 
-__all__ = ['Protocol', 'RpcProtocol', 'TunnelProtocol']
+__all__ = ['Protocol', 'RpcProtocol', 'TunnelProtocol', 'VpnProtocol']

sjrpc/core/protocols/vpn.py

+from __future__ import absolute_import
+
+import os
+import struct
+import fcntl
+
+from sjrpc.core.protocols import TunnelProtocol
+
+__all__ = ['VpnProtocol']
+
+class _FileSocket(object):
+
+    '''
+    A fake Socket interface for files.
+    '''
+
+    def __init__(self, file_):
+        self.file = file_
+
+    def recv(self, size):
+        self.file.read(size)
+
+    def send(self, data):
+        self.file.write(data)
+        return len(data)
+
+    def fileno(self):
+        return self.file.fileno()
+
+    def setblocking(self, blocking):
+        if not blocking:
+            # Disable blocking mode on devzero:
+            current_flags = fcntl.fcntl(self.fileno(), fcntl.F_GETFL)
+            fcntl.fcntl(self.fileno(), fcntl.F_SETFL, current_flags | os.O_NONBLOCK)
+        else:
+            raise NotImplementedError('Not implemented')
+
+
+class VpnProtocol(TunnelProtocol):
+
+    '''
+    A VPN protocol which spawn a network interface and tunnel all its traffic
+    through the sjRpc tunnel.
+
+    :param inherited: All options (except endpoint) are inherited from
+                      :class:`TunnelProtocol`.
+    :param tun_prefix: the prefix name of the spawned interface
+    :param tun_mode: which can be VpnProtocol.IFF_TUN or VpnProtocol.IFF_TAP
+
+    The user starting the sjRpc process must have the CAP_NET_ADMIN capability,
+    by default, only root have this capability.
+
+    .. warning::
+       This protocol is a proof of concept and should not be used in production
+       software.
+    '''
+
+    # Taken from linux/if_tun.h:
+    TUNSETIFF = 0x400454ca
+    IFF_TUN = 0x0001
+    IFF_TAP = 0x0002
+
+    # Default values:
+    DEFAULT_TUN_PREFIX = 'tun'
+    DEFAULT_TUN_MODE = IFF_TAP
+
+    def __init__(self, *args, **kwargs):
+        tun_prefix = kwargs.pop('tun_prefix', VpnProtocol.DEFAULT_TUN_PREFIX)
+        tun_mode = kwargs.pop('tun_mode', VpnProtocol.DEFAULT_TUN_MODE)
+
+        ftun = open('/dev/net/tun', 'r+b')
+        # Create the tunnel and get its final name:
+        create_tun_arg = struct.pack('16sH', tun_prefix + '%d', tun_mode)
+        tun = fcntl.ioctl(ftun, VpnProtocol.TUNSETIFF, create_tun_arg)
+        self.tun_name = tun[:16].rstrip('\0')
+
+        kwargs['endpoint'] = _FileSocket(ftun)
+        super(VpnProtocol, self).__init__(*args, **kwargs)