#!/usr/bin/env python3
#
# xapi plugin script to update the cache of configuration items in the
# ovs-vswitchd configuration that are managed in the xapi database when
# integrated with Citrix management tools.

# Copyright (C) 2009, 2010, 2011, 2012, 2013 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.

# TBD: - error handling needs to be improved.  Currently this can leave
# TBD:   the system in a bad state if anything goes wrong.

import contextlib
import os
import re

import XenAPIPlugin
from xcp.cmd import runCmd

vsctl = "/usr/bin/ovs-vsctl"
ofctl = "/usr/bin/ovs-ofctl"
bootstrap_cacert = "/etc/openvswitch/vswitchd.cacert"
preinstalled_cacert = "/etc/stunnel/certs/sdn-controller-ca.pem"
iptablectl = "/etc/xapi.d/plugins/firewall-port"


# Delete the CA certificate, so that we go back to boot-strapping mode
def delete_cacert():
    if os.path.exists(bootstrap_cacert):
        os.remove(bootstrap_cacert)


def update(session, args):
    pools = session.xenapi.pool.get_all()
    # We assume there is only ever one pool...
    if len(pools) == 0:
        raise XenAPIPlugin.Failure("NO_POOL_FOR_HOST", [])
    if len(pools) > 1:
        raise XenAPIPlugin.Failure("MORE_THAN_ONE_POOL_FOR_HOST", [])

    new_controller = False
    pool = session.xenapi.pool.get_record(pools[0])

    bootstrap = False
    controller = ""
    controller_protocol = ""
    controller_address = ""
    controller_port = ""

    controllers = session.xenapi.SDN_controller.get_all()
    if len(controllers) > 0:
        # There is at most one SDN_controller record.
        controller_protocol = session.xenapi.SDN_controller.get_protocol(controllers[0])
        controller_address = session.xenapi.SDN_controller.get_address(controllers[0])
        controller_port = session.xenapi.SDN_controller.get_port(controllers[0])
        bootstrap, controller = composeController(
            controller_protocol, controller_address, controller_port
        )

    ret_str = ""
    currentControllers = vswitchCurrentControllers()

    if not controller and currentControllers:
        delete_cacert()
        runCmd([iptablectl, "close", "6640"])
        runCmd([iptablectl, "close", "6653"])
        with contextlib.suppress(Exception):
            emergency_reset(session, None)
        removeControllerCfg()
        ret_str += "Successfully removed controller config.  "
    # controller cannot be empty, otherwise, this will always be True.
    elif controller and controller not in currentControllers:
        delete_cacert()
        with contextlib.suppress(Exception):
            emergency_reset(session, None)
        setControllerCfg(bootstrap, controller)
        new_controller = True
        ret_str += "Successfully set controller to %s.  " % controller

    pool_fail_mode = pool["other_config"].get("vswitch-controller-fail-mode")

    bton = {}

    for rec in session.xenapi.network.get_all_records().values():
        with contextlib.suppress(KeyError):
            bton[rec["bridge"]] = rec

    # If new controller, get management MAC addresses from XAPI now
    # in case fail_mode set to secure which may affect XAPI access
    mgmt_bridge = None
    host_mgmt_mac = None
    host_mgmt_device = None
    pool_mgmt_macs = {}
    if new_controller:
        query = 'field "management"="true"'
        recs = session.xenapi.PIF.get_all_records_where(query)
        for rec in recs.values():
            pool_mgmt_macs[rec.get("MAC")] = rec.get("device")

    dib_changed = False
    fail_mode_changed = False
    for bridge in vswitchCfgQuery(["list-br"]).split():
        if bridge not in bton:
            continue
        network = bton[bridge]
        bridge = vswitchCfgQuery(["br-to-parent", bridge])

        xapi_dib = network["other_config"].get("vswitch-disable-in-band")
        if not xapi_dib:
            xapi_dib = ""

        ovs_dib = vswitchCfgQuery(
            [
                "--",
                "--if-exists",
                "get",
                "Bridge",
                bridge,
                "other_config:disable-in-band",
            ]
        ).strip('"')

        # Do nothing if setting is invalid, and warn the user.
        if xapi_dib not in ["true", "false", ""]:
            ret_str += '"%s" is an invalid value for vswitch-disable-in-band on %s  ' % (
                xapi_dib,
                bridge,
            )

        # Change bridge disable-in-band option if XAPI and OVS states differ.
        elif xapi_dib != ovs_dib:
            # 'true' or 'false'
            if xapi_dib:
                vswitchCfgMod(
                    [
                        "--",
                        "set",
                        "Bridge",
                        bridge,
                        "other_config:disable-in-band=" + xapi_dib,
                    ]
                )
            # '' or None
            else:
                vswitchCfgMod(
                    [
                        "--",
                        "remove",
                        "Bridge",
                        bridge,
                        "other_config",
                        "disable-in-band",
                    ]
                )
            dib_changed = True

        # Change bridge fail_mode if XAPI state differs from OVS state.
        bridge_fail_mode = vswitchCfgQuery(
            ["get", "Bridge", bridge, "fail_mode"]
        ).strip('[]"')

        try:
            other_config = bton[bridge]["other_config"]
            fail_mode = other_config["vswitch-controller-fail-mode"]
        except KeyError:
            fail_mode = None

        if fail_mode not in ["secure", "standalone"]:
            fail_mode = pool_fail_mode

        if fail_mode != "secure":
            fail_mode = "standalone"

        if bridge_fail_mode != fail_mode:
            vswitchCfgMod(["--", "set", "Bridge", bridge, "fail_mode=%s" % fail_mode])
            fail_mode_changed = True

        # Determine local mgmt MAC address if host being added to secure
        # pool so we can add default flows to allow management traffic
        if new_controller and fail_mode_changed and pool_fail_mode == "secure":
            oc = vswitchCfgQuery(["get", "Bridge", bridge, "other-config"])
            m = re.match('.*hwaddr="([0-9a-fA-F:].*)".*', oc)
            if m and m.group(1) in pool_mgmt_macs:
                mgmt_bridge = bridge
                host_mgmt_mac = m.group(1)
                host_mgmt_device = pool_mgmt_macs[host_mgmt_mac]

    if all([host_mgmt_mac, mgmt_bridge, host_mgmt_device]):
        tp = "idle_timeout=0,priority=0"
        port = vswitchCfgQuery(["get", "interface", host_mgmt_device, "ofport"])

        addFlow(mgmt_bridge, "%s,in_port=%s,arp,nw_proto=1,actions=local" % (tp, port))
        addFlow(
            mgmt_bridge,
            "%s,in_port=local,arp,dl_src=%s,actions=%s" % (tp, host_mgmt_mac, port),
        )
        addFlow(
            mgmt_bridge,
            "%s,in_port=%s,dl_dst=%s,actions=local" % (tp, port, host_mgmt_mac),
        )
        addFlow(
            mgmt_bridge,
            "%s,in_port=local,dl_src=%s,actions=%s" % (tp, host_mgmt_mac, port),
        )

    if dib_changed:
        ret_str += "Updated in-band management.  "

    if fail_mode_changed:
        ret_str += "Updated fail_mode.  "

    return ret_str if ret_str else "No change to configuration"


def vswitchCurrentControllers():
    controllers = vswitchCfgQuery(["get-manager"])
    return controllers.split("\n") if controllers else []


def removeControllerCfg():
    vswitchCfgMod(["--", "del-manager", "--", "del-ssl"])


def setControllerCfg(bootstrap, controller):
    # /etc/xensource/xapi-ssl.pem is mentioned twice below because it
    # contains both the private key and the certificate.
    if bootstrap:
        # For active ssl, do not need to turn on TCP port 6640 on host.
        runCmd([iptablectl, "close", "6640"])
        vswitchCfgMod(
            [
                "--",
                "del-manager",
                "--",
                "del-ssl",
                "--",
                "--bootstrap",
                "set-ssl",
                "/etc/xensource/xapi-ssl.pem",
                "/etc/xensource/xapi-ssl.pem",
                bootstrap_cacert,
                "--",
                "set-manager",
                controller,
            ]
        )
    else:
        # For passive ssl, only TCP port 6640 is meaningful.
        # Turn on the port of the host.
        runCmd([iptablectl, "open", "6640"])
        vswitchCfgMod(
            [
                "--",
                "del-manager",
                "--",
                "del-ssl",
                "--",
                "set-ssl",
                "/etc/xensource/xapi-ssl.pem",
                "/etc/xensource/xapi-ssl.pem",
                preinstalled_cacert,
                "--",
                "set-manager",
                controller,
            ]
        )
    runCmd([iptablectl, "open", "6653"])


def composeController(protocol, controllerIP, tcpport):
    bootstrap = False
    controller = ""
    if protocol == "ssl":
        bootstrap = True
        controller = protocol + ":" + controllerIP + ":" + tcpport
    elif protocol == "pssl":
        controller = protocol + ":6640"
    return bootstrap, controller


def vswitchCfgQuery(action_args):
    cmd = [vsctl, "-vconsole:off", *action_args]
    (rc, output) = runCmd(cmd, with_stdout=True)
    if rc != 0 or len(output) == 0 or output[0] is None:
        output = ""
    else:
        output = output[0].strip()
    return output


def vswitchCfgMod(action_args):
    cmd = [vsctl, "--timeout=5", "-vconsole:off", *action_args]
    exitcode = runCmd(cmd)
    if exitcode != 0:
        raise XenAPIPlugin.Failure(
            "VSWITCH_CONFIG_MOD_FAILURE", [str(exitcode), str(action_args)]
        )


def emergency_reset(session, args):
    cmd = [vsctl, "--timeout=5", "emer-reset"]
    exitcode = runCmd(cmd)
    if exitcode != 0:
        raise XenAPIPlugin.Failure("VSWITCH_EMER_RESET_FAILURE", [str(exitcode)])

    return "Successfully reset configuration"


def addFlow(switch, flow):
    cmd = [ofctl, "add-flow", switch, flow]
    exitcode = runCmd(cmd)
    if exitcode != 0:
        raise XenAPIPlugin.Failure(
            "VSWITCH_ADD_FLOW_FAILURE", [str(exitcode), str(switch), str(flow)]
        )


if __name__ == "__main__":
    XenAPIPlugin.dispatch({"update": update, "emergency_reset": emergency_reset})
