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Diffstat (limited to 'Monitoring/MonitoringService/Driver/SshTunnel.py')
| -rw-r--r-- | Monitoring/MonitoringService/Driver/SshTunnel.py | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/Monitoring/MonitoringService/Driver/SshTunnel.py b/Monitoring/MonitoringService/Driver/SshTunnel.py new file mode 100644 index 0000000..f2b7d39 --- /dev/null +++ b/Monitoring/MonitoringService/Driver/SshTunnel.py @@ -0,0 +1,178 @@ +''' +Created on Jan 14, 2013 + +@author: steger +''' + +import select +import SocketServer +from Driver import Driver +from SshExec import SshDriver +from threading import Thread +from SshExec import SshExec + +class SshTunnel(SshDriver): + ''' + @summary: this class extends L{SshDriver} and establishes a connection + to the requested SSH server and sets up local port + forwarding (the openssh -L option) from a local port through a tunneled + connection to a destination reachable from the SSH server machine. + @ivar t: the thread container + @type t: threading.Thread or None + ''' + + class ForwardServer (SocketServer.ThreadingTCPServer): + daemon_threads = True + allow_reuse_address = True + + class Handler (SocketServer.BaseRequestHandler): + def handle(self): + try: + chan = self.ssh_transport.open_channel('direct-tcpip', + (self.chain_host, self.chain_port), + self.request.getpeername()) + except Exception, e: + Driver.logger.debug('Incoming request to %s:%d failed: %s' % (self.chain_host, + self.chain_port, + repr(e))) + return + if chan is None: + Driver.logger.debug('Incoming request to %s:%d was rejected by the SSH server.' % + (self.chain_host, self.chain_port)) + return + + Driver.logger.debug('Tunnel open %r -> %r -> %r' % (self.request.getpeername(), + chan.getpeername(), (self.chain_host, self.chain_port))) + while True: + r, _, _ = select.select([self.request, chan], [], []) + if self.request in r: + data = self.request.recv(1024) + if len(data) == 0: + break + chan.send(data) + if chan in r: + data = chan.recv(1024) + if len(data) == 0: + break + self.request.send(data) + chan.close() + self.request.close() + Driver.logger.debug('Tunnel closed from %r' % (self.request.getpeername(),)) + + def __init__(self): + ''' + @summary: allocates thread pointer container + ''' + SshDriver.__init__(self) + self.t = None + + def connect(self, host, credential, localport, port, remoteserver, remoteport, known_host = None): + ''' + @summary: set up the tunnel connection + @param host: the host name of the remote server acting a port forwarder + @type host: str + @param credential: the secret to use for connection set up + @type credential: L{Credential} + @param localport: the local port entry mapped to the remoteport + @type localport: int + @param port: the port of the forwarder ssh server + @type port: int + @param remoteserver: the sink of the tunnel + @type remoteserver: str + @param remoteport: the port of the tunnel sink + @type remoteport: int + @param known_host: a file name containing host signatures to check, if None AutoAddPolicy applies + @type known_host: str + ''' + SshDriver.connect(self, host, credential, port, known_host) + self.logger.info('Now forwarding port %d to %s:%d ...' % (localport, remoteserver, remoteport)) + self.t = Thread(target = self._tran, kwargs = {'localport': localport, 'remoteserver': remoteserver, 'remoteport': remoteport}) + self.t.daemon = True + self.t.start() + + def _tran(self, localport, remoteserver, remoteport): + ''' + @summary: thread worker to transport data over the tunnel + @param localport: the local port entry mapped to the remoteport + @type localport: int + @param remoteserver: the sink of the tunnel + @type remoteserver: str + @param remoteport: the port of the tunnel sink + @type remoteport: int + ''' + try: + # this is a little convoluted, but lets me configure things for the Handler + # object. (SocketServer doesn't give Handlers any way to access the outer + # server normally.) + class SubHander (self.Handler): + chain_host = remoteserver + chain_port = remoteport + ssh_transport = self.client.get_transport() + self.service = self.ForwardServer(('', localport), SubHander) + self.service.serve_forever() + except KeyboardInterrupt: + self.logger.debug('C-c: Port forwarding stopped.') + self.close() + + def close(self): + ''' + @summary: stops the thread and tears down the tunnel + ''' + if self.t is None: + return + self.t.join(timeout = self.timeout) + self.t = None + self.service.shutdown() + self.logger.info('Port forwarding stopped @ %s.' % self.host) + SshDriver.close(self) + + +class SshExecTunnel(SshTunnel): + ''' + @summary: an extension of the L{SshTunnel} driver to execute commands + on the remote machine accessed via the tunnel + @ivar command: the string representation of the command to run + @type command: str + @ivar localdriver: the representation of an ssh client connecting over an existing ssh tunnel + @type localdriver: L{SshExec} + ''' + + def __init__(self, host, credential, localport, port, remoteserver, remoteport, remotecredential = None, command = "echo helloworld @ `hostname`", known_host = None): + ''' + @summary: initializes an ssh connection and stores a default command + @param host: the host name of the remote server acting a port forwarder + @type host: str + @param credential: the secret to use for tunnel set up + @type credential: L{Credential} + @param localport: the local port entry mapped to the remoteport + @type localport: int + @param port: the port of the forwarder ssh server + @type port: int + @param remoteserver: the sink of the tunnel + @type remoteserver: str + @param remoteport: the port of the tunnel sink + @type remoteport: int + @param remotecredential: the secret to use for connection set up, if None then we fall back to the credential + @type remotecredential: L{Credential} or None + @param command: the default remote command + @type command: str + @param known_host: a file name containing host signatures to check, if None AutoAddPolicy applies + @type known_host: str + ''' + SshTunnel.__init__(self) + self.connect(host, credential, localport, port, remoteserver, remoteport, known_host) + self.command = command + if remotecredential is None: + remotecredential = credential + self.localdriver = SshExec(host = 'localhost', credential = remotecredential, port = localport, command = command, known_host = None) + self.logger.info("connected over tunnel") + + def execute(self, command = None): + ''' + @summary: executes a remote command + @param command: the command to run, if None, the default command is issued + @type command: str or None + @return: the standard output of the command run + @rtype: paramico.ChannelFile + ''' + return self.localdriver.execute(command) |