# Copyright (c) 2011, 2012 Nicira, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""
rpcserver is an XML RPC server that allows RPC client to initiate tests
"""

from __future__ import print_function

import exceptions
import sys

import six.moves.xmlrpc_client
from twisted.internet import reactor
from twisted.internet.error import CannotListenError
from twisted.web import xmlrpc
from twisted.web import server

import tcp
import udp
import util
import vswitch


class TestArena(xmlrpc.XMLRPC):
    """
    This class contains all the functions that ovs-test client will call
    remotely. The caller is responsible to use designated handleIds
    for designated methods (e.g. do not mix UDP and TCP handles).
    """

    def __init__(self):
        xmlrpc.XMLRPC.__init__(self, allowNone=True)
        self.handle_id = 1
        self.handle_map = {}
        self.bridges = set()
        self.pbridges = set()
        self.ports = set()
        self.request = None

    def __acquire_handle(self, value):
        """
        Allocates new handle and assigns value object to it
        """
        handle = self.handle_id
        self.handle_map[handle] = value
        self.handle_id += 1
        return handle

    def __get_handle_resources(self, handle):
        """
        Return resources that were assigned to handle
        """
        return self.handle_map[handle]

    def __delete_handle(self, handle):
        """
        Releases handle from handle_map
        """
        del self.handle_map[handle]

    def cleanup(self):
        """
        Delete all remaining bridges and ports if ovs-test client did not had
        a chance to remove them. It is necessary to call this function if
        ovs-test server is abruptly terminated when doing the tests.
        """
        for port in self.ports:
            # Remove ports that were added to existing bridges
            vswitch.ovs_vsctl_del_port_from_bridge(port)

        for bridge in self.bridges:
            # Remove bridges that were added for L3 tests
            vswitch.ovs_vsctl_del_bridge(bridge)

        for pbridge in self.pbridges:
            # Remove bridges that were added for VLAN tests
            vswitch.ovs_vsctl_del_pbridge(pbridge[0], pbridge[1])

    def render(self, request):
        """
        This method overrides the original XMLRPC.render method so that it
        would be possible to get the XML RPC client IP address from the
        request object.
        """
        self.request = request
        return xmlrpc.XMLRPC.render(self, request)

    def xmlrpc_get_my_address(self):
        """
        Returns the RPC client's IP address.
        """
        return self.request.getClientIP()

    def xmlrpc_get_my_address_from(self, his_ip, his_port):
        """
        Returns the ovs-test server IP address that the other ovs-test server
        with the given ip will see.
        """
        server1 = six.moves.xmlrpc_client.Server("http://%s:%u/" %
                                                 (his_ip, his_port))
        return server1.get_my_address()

    def xmlrpc_create_udp_listener(self, port):
        """
        Creates a UDP listener that will receive packets from UDP sender
        """
        try:
            listener = udp.UdpListener()
            reactor.listenUDP(port, listener)
            handle_id = self.__acquire_handle(listener)
        except CannotListenError:
            return -1
        return handle_id

    def xmlrpc_create_udp_sender(self, host, count, size, duration):
        """
        Send UDP datagrams to UDP listener
        """
        sender = udp.UdpSender(tuple(host), count, size, duration)
        reactor.listenUDP(0, sender)
        handle_id = self.__acquire_handle(sender)
        return handle_id

    def xmlrpc_get_udp_listener_results(self, handle):
        """
        Returns number of datagrams that were received
        """
        listener = self.__get_handle_resources(handle)
        return listener.getResults()

    def xmlrpc_get_udp_sender_results(self, handle):
        """
        Returns number of datagrams that were sent
        """
        sender = self.__get_handle_resources(handle)
        return sender.getResults()

    def xmlrpc_close_udp_listener(self, handle):
        """
        Releases UdpListener and all its resources
        """
        listener = self.__get_handle_resources(handle)
        listener.transport.stopListening()
        self.__delete_handle(handle)
        return 0

    def xmlrpc_close_udp_sender(self, handle):
        """
        Releases UdpSender and all its resources
        """
        sender = self.__get_handle_resources(handle)
        sender.transport.stopListening()
        self.__delete_handle(handle)
        return 0

    def xmlrpc_create_tcp_listener(self, port):
        """
        Creates a TcpListener that will accept connection from TcpSender
        """
        try:
            listener = tcp.TcpListenerFactory()
            port = reactor.listenTCP(port, listener)
            handle_id = self.__acquire_handle((listener, port))
            return handle_id
        except CannotListenError:
            return -1

    def xmlrpc_create_tcp_sender(self, his_ip, his_port, duration):
        """
        Creates a TcpSender that will connect to TcpListener
        """
        sender = tcp.TcpSenderFactory(duration)
        connector = reactor.connectTCP(his_ip, his_port, sender)
        handle_id = self.__acquire_handle((sender, connector))
        return handle_id

    def xmlrpc_get_tcp_listener_results(self, handle):
        """
        Returns number of bytes received
        """
        (listener, _) = self.__get_handle_resources(handle)
        return listener.getResults()

    def xmlrpc_get_tcp_sender_results(self, handle):
        """
        Returns number of bytes sent
        """
        (sender, _) = self.__get_handle_resources(handle)
        return sender.getResults()

    def xmlrpc_close_tcp_listener(self, handle):
        """
        Releases TcpListener and all its resources
        """
        try:
            (_, port) = self.__get_handle_resources(handle)
            port.loseConnection()
            self.__delete_handle(handle)
        except exceptions.KeyError:
            return -1
        return 0

    def xmlrpc_close_tcp_sender(self, handle):
        """
        Releases TcpSender and all its resources
        """
        try:
            (_, connector) = self.__get_handle_resources(handle)
            connector.disconnect()
            self.__delete_handle(handle)
        except exceptions.KeyError:
            return -1
        return 0

    def xmlrpc_create_test_bridge(self, bridge, iface):
        """
        This function creates a physical bridge from iface. It moves the
        IP configuration from the physical interface to the bridge.
        """
        ret = vswitch.ovs_vsctl_add_bridge(bridge)
        if ret == 0:
            self.pbridges.add((bridge, iface))
            util.interface_up(bridge)
            (ip_addr, mask) = util.interface_get_ip(iface)
            util.interface_assign_ip(bridge, ip_addr, mask)
            util.move_routes(iface, bridge)
            util.interface_assign_ip(iface, "0.0.0.0", "255.255.255.255")
            ret = vswitch.ovs_vsctl_add_port_to_bridge(bridge, iface)
            if ret == 0:
                self.ports.add(iface)
            else:
                util.interface_assign_ip(iface, ip_addr, mask)
                util.move_routes(bridge, iface)
                vswitch.ovs_vsctl_del_bridge(bridge)

        return ret

    def xmlrpc_del_test_bridge(self, bridge, iface):
        """
        This function deletes the test bridge and moves its IP configuration
        back to the physical interface.
        """
        ret = vswitch.ovs_vsctl_del_pbridge(bridge, iface)
        self.pbridges.discard((bridge, iface))
        return ret

    def xmlrpc_get_iface_from_bridge(self, brname):
        """
        Tries to figure out physical interface from bridge.
        """
        return vswitch.ovs_get_physical_interface(brname)

    def xmlrpc_create_bridge(self, brname):
        """
        Creates an OVS bridge.
        """
        ret = vswitch.ovs_vsctl_add_bridge(brname)
        if ret == 0:
            self.bridges.add(brname)
        return ret

    def xmlrpc_del_bridge(self, brname):
        """
        Deletes an OVS bridge.
        """
        ret = vswitch.ovs_vsctl_del_bridge(brname)
        if ret == 0:
            self.bridges.discard(brname)
        return ret

    def xmlrpc_is_ovs_bridge(self, bridge):
        """
        This function verifies whether given interface is an ovs bridge.
        """
        return vswitch.ovs_vsctl_is_ovs_bridge(bridge)

    def xmlrpc_add_port_to_bridge(self, bridge, port):
        """
        Adds a port to the OVS bridge.
        """
        ret = vswitch.ovs_vsctl_add_port_to_bridge(bridge, port)
        if ret == 0:
            self.ports.add(port)
        return ret

    def xmlrpc_del_port_from_bridge(self, port):
        """
        Removes a port from OVS bridge.
        """
        ret = vswitch.ovs_vsctl_del_port_from_bridge(port)
        if ret == 0:
            self.ports.discard(port)
        return ret

    def xmlrpc_ovs_vsctl_set(self, table, record, column, key, value):
        """
        This function allows to alter OVS database.
        """
        return vswitch.ovs_vsctl_set(table, record, column, key, value)

    def xmlrpc_interface_up(self, iface):
        """
        This function brings up given interface.
        """
        return util.interface_up(iface)

    def xmlrpc_interface_assign_ip(self, iface, ip_address, mask):
        """
        This function allows to assing ip address to the given interface.
        """
        return util.interface_assign_ip(iface, ip_address, mask)

    def xmlrpc_get_interface(self, address):
        """
        Finds first interface that has given address
        """
        return util.get_interface(address)

    def xmlrpc_get_interface_mtu(self, iface):
        """
        Returns MTU of the given interface
        """
        return util.get_interface_mtu(iface)

    def xmlrpc_uname(self):
        """
        Return information about running kernel
        """
        return util.uname()

    def xmlrpc_get_driver(self, iface):
        """
        Returns driver version
        """
        return util.get_driver(iface)

    def xmlrpc_get_interface_from_routing_decision(self, ip):
        """
        Returns driver version
        """
        return util.get_interface_from_routing_decision(ip)


def start_rpc_server(port):
    """
    This function creates a RPC server and adds it to the Twisted Reactor.
    """
    rpc_server = TestArena()
    reactor.listenTCP(port, server.Site(rpc_server))
    try:
        print("Starting RPC server\n")
        sys.stdout.flush()
        # If this server was started from ovs-test client then we must flush
        # STDOUT so that client would know that server is ready to accept
        # XML RPC connections.
        reactor.run()
    finally:
        rpc_server.cleanup()
