[mirror_ifupdown2.git] / addons / vrf.py

#!/usr/bin/python
#
# Copyright 2014 Cumulus Networks, Inc. All rights reserved.
# Author: Roopa Prabhu, roopa@cumulusnetworks.com
#

import os
import signal
import errno 
import subprocess
import atexit
from ifupdown.iface import *
import ifupdown.policymanager as policymanager
import ifupdownaddons
import ifupdown.rtnetlink_api as rtnetlink_api
import ifupdown.ifupdownflags as ifupdownflags
from ifupdownaddons.modulebase import moduleBase
from ifupdownaddons.bondutil import bondutil
from ifupdownaddons.iproute2 import iproute2
from ifupdownaddons.dhclient import dhclient

class vrfPrivFlags:
    PROCESSED = 0x1

class vrf(moduleBase):
    """  ifupdown2 addon module to configure vrfs """
    _modinfo = { 'mhelp' : 'vrf configuration module',
                    'attrs' : {
                    'vrf-table':
                         {'help' : 'vrf device table id. key to ' +
                                   'creating a vrf device',
                          'example': ['vrf-table-id 1']},
                    'vrf':
                         {'help' : 'vrf the interface is part of.',
                          'example': ['vrf blue']}}}

    iproute2_vrf_filename = '/etc/iproute2/rt_tables.d/ifupdown2_vrf_map.conf'
    iproute2_vrf_filehdr = '# This file is autogenerated by ifupdown2.\n' + \
                           '# It contains the vrf name to table mapping.\n' + \
                           '# Reserved table range %s %s\n'
    VRF_TABLE_START = 1001
    VRF_TABLE_END = 5000

    system_reserved_rt_tables = {'255' : 'local', '254' : 'main', 
                                 '253' : 'default', '0' : 'unspec'}

    def __init__(self, *args, **kargs):
        ifupdownaddons.modulebase.moduleBase.__init__(self, *args, **kargs)
        self.ipcmd = None
        self.bondcmd = None
        self.dhclientcmd = None
        self.name = self.__class__.__name__
        if ifupdownflags.flags.PERFMODE:
            # if perf mode is set, remove vrf map file.
            # start afresh. PERFMODE is set at boot
            if os.path.exists(self.iproute2_vrf_filename):
                try:
                    self.logger.info('vrf: removing file %s'
                                     %self.iproute2_vrf_filename)
                    os.remove(self.iproute2_vrf_filename)
                except Exception, e:
                    self.logger.debug('vrf: removing file failed (%s)'
                                      %str(e))
        try:
            ip_rules = self.exec_command('/sbin/ip rule show').splitlines()
            self.ip_rule_cache = [' '.join(r.split()) for r in ip_rules]
        except Exception, e:
            self.ip_rule_cache = []
            self.logger.warn('%s' %str(e))

        try:
            ip_rules = self.exec_command('/sbin/ip -6 rule show').splitlines()
            self.ip6_rule_cache = [' '.join(r.split()) for r in ip_rules]
        except Exception, e:
            self.ip6_rule_cache = []
            self.logger.warn('%s' %str(e))

        #self.logger.debug("vrf: ip rule cache")
        #self.logger.info(self.ip_rule_cache)

        #self.logger.info("vrf: ip -6 rule cache")
        #self.logger.info(self.ip6_rule_cache)

        self._iproute2_vrf_map_initialized = False
        self.iproute2_vrf_map = {}
        self.iproute2_vrf_map_fd = None
        self.iproute2_vrf_map_sync_to_disk = False

        self.vrf_table_id_start = policymanager.policymanager_api.get_module_globals(module_name=self.__class__.__name__, attr='vrf-table-id-start')
        if not self.vrf_table_id_start:
            self.vrf_table_id_start = self.VRF_TABLE_START
        self.vrf_table_id_end = policymanager.policymanager_api.get_module_globals(module_name=self.__class__.__name__, attr='vrf-table-id-end')
        if not self.vrf_table_id_end:
            self.vrf_table_id_end = self.VRF_TABLE_END
        self.vrf_max_count = policymanager.policymanager_api.get_module_globals(module_name=self.__class__.__name__, attr='vrf-max-count')

        self.vrf_fix_local_table = True
        self.vrf_count = 0
        self.vrf_mgmt_devname = policymanager.policymanager_api.get_module_globals(module_name=self.__class__.__name__, attr='vrf-mgmt-devname')
        self.vrf_helper = policymanager.policymanager_api.get_module_globals(module_name=self.__class__.__name__, attr='vrf-helper')

    def _iproute2_vrf_map_initialize(self, writetodisk=True):
        if self._iproute2_vrf_map_initialized:
            return

        # XXX: check for vrf reserved overlap in /etc/iproute2/rt_tables
        self.iproute2_vrf_map = {}
        iproute2_vrf_map_force_rewrite = False
        # read or create /etc/iproute2/rt_tables.d/ifupdown2.vrf_map
        if os.path.exists(self.iproute2_vrf_filename):
            vrf_map_fd = open(self.iproute2_vrf_filename, 'r+')
            lines = vrf_map_fd.readlines()
            for l in lines:
                l = l.strip()
                if l[0] == '#':
                    continue
                try:
                    (table, vrf_name) = l.strip().split()
                    if self.iproute2_vrf_map.get(int(table)):
                        # looks like the existing file has
                        # duplicate entries, force rewrite of the
                        # file
                        iproute2_vrf_map_force_rewrite = True
                        continue
                    self.iproute2_vrf_map[int(table)] = vrf_name
                except Exception, e:
                    self.logger.info('vrf: iproute2_vrf_map: unable to parse %s'
                                     %l)
                    pass

        vrfs = self.ipcmd.link_get_vrfs()
        running_vrf_map = {}
        if vrfs:
            for v, lattrs in vrfs.iteritems():
                table = lattrs.get('table', None)
                if table:
                   running_vrf_map[int(table)] = v

        if (not running_vrf_map or (running_vrf_map != self.iproute2_vrf_map)):
            self.iproute2_vrf_map = running_vrf_map
            iproute2_vrf_map_force_rewrite = True

        self.iproute2_vrf_map_fd = None
        if writetodisk:
            if iproute2_vrf_map_force_rewrite:
                # reopen the file and rewrite the map
                self._iproute2_vrf_map_open(True, False)
            else:
                self._iproute2_vrf_map_open(False, True)

        self.iproute2_vrf_map_sync_to_disk = False
        atexit.register(self._iproute2_vrf_map_sync_to_disk)

        self.logger.info("vrf: dumping iproute2_vrf_map")
        self.logger.info(self.iproute2_vrf_map)

        last_used_vrf_table = None
        for t in range(self.vrf_table_id_start,
                       self.vrf_table_id_end):
            if not self.iproute2_vrf_map.get(t):
                break
            last_used_vrf_table = t
        self.last_used_vrf_table = last_used_vrf_table
        self._iproute2_vrf_map_initialized = True
        self.vrf_count = len(self.iproute2_vrf_map)

    def _iproute2_vrf_map_sync_to_disk(self):
        if (ifupdownflags.flags.DRYRUN or
            not self.iproute2_vrf_map_sync_to_disk):
            return
        self.logger.info('vrf: syncing table map to %s'
                         %self.iproute2_vrf_filename)
        with open(self.iproute2_vrf_filename, 'w') as f:
            f.write(self.iproute2_vrf_filehdr %(self.vrf_table_id_start,
                    self.vrf_table_id_end))
            for t, v in self.iproute2_vrf_map.iteritems():
                f.write('%s %s\n' %(t, v))
            f.flush()

    def _iproute2_vrf_map_open(self, sync_vrfs=False, append=False):
        self.logger.info('vrf: syncing table map to %s'
                         %self.iproute2_vrf_filename)
        if ifupdownflags.flags.DRYRUN:
            return
        fmode = 'a+' if append else 'w'
        try:
            self.iproute2_vrf_map_fd = open(self.iproute2_vrf_filename,
                                         '%s' %fmode)
        except Exception, e:
            self.log_warn('vrf: error opening %s (%s)'
                          %(self.iproute2_vrf_filename, str(e)))
            return

        if not append:
            # write file header
            self.iproute2_vrf_map_fd.write(self.iproute2_vrf_filehdr
                                           %(self.vrf_table_id_start,
                                             self.vrf_table_id_end))
            for t, v in self.iproute2_vrf_map.iteritems():
                self.iproute2_vrf_map_fd.write('%s %s\n' %(t, v))
            self.iproute2_vrf_map_fd.flush()

    def _is_vrf(self, ifaceobj):
        if ifaceobj.get_attr_value_first('vrf-table'):
            return True
        return False

    def get_upper_ifacenames(self, ifaceobj, ifacenames_all=None):
        """ Returns list of interfaces dependent on ifaceobj """

        vrf_table = ifaceobj.get_attr_value_first('vrf-table')
        if vrf_table:
            ifaceobj.link_type = ifaceLinkType.LINK_MASTER
            ifaceobj.link_kind |= ifaceLinkKind.VRF
            ifaceobj.role |= ifaceRole.MASTER
        vrf_iface_name = ifaceobj.get_attr_value_first('vrf')
        if not vrf_iface_name:
            return None
        ifaceobj.link_type = ifaceLinkType.LINK_SLAVE
        ifaceobj.link_privflags |= ifaceLinkPrivFlags.VRF_SLAVE

        return [vrf_iface_name]

    def get_upper_ifacenames_running(self, ifaceobj):
        return None

    def _get_iproute2_vrf_table(self, vrf_dev_name):
        for t, v in self.iproute2_vrf_map.iteritems():
            if v == vrf_dev_name:
                return str(t)
        return None

    def _get_avail_vrf_table_id(self):
        if self.last_used_vrf_table == None:
            table_id_start = self.vrf_table_id_start
        else:
            table_id_start = self.last_used_vrf_table + 1
        for t in range(table_id_start,
                       self.vrf_table_id_end):
            if not self.iproute2_vrf_map.get(t):
                self.last_used_vrf_table = t
                return str(t)
        return None

    def _iproute2_is_vrf_tableid_inuse(self, vrf_dev_name, table_id):
        old_vrf_name = self.iproute2_vrf_map.get(int(table_id))
        if old_vrf_name and old_vrf_name != vrf_dev_name:
            self.log_error('table id %s already assigned to vrf dev %s'
                           %(table_id, old_vrf_name))

    def _iproute2_vrf_table_entry_add(self, vrf_dev_name, table_id):
        old_vrf_name = self.iproute2_vrf_map.get(int(table_id))
        if not old_vrf_name:
            self.iproute2_vrf_map[int(table_id)] = vrf_dev_name
            if self.iproute2_vrf_map_fd:
                self.iproute2_vrf_map_fd.write('%s %s\n'
                                               %(table_id, vrf_dev_name))
                self.iproute2_vrf_map_fd.flush()
                self.vrf_count += 1
            return

        if old_vrf_name != vrf_dev_name:
            self.log_error('table id %d already assigned to vrf dev %s'
                           %(table_id, old_vrf_name))

    def _iproute2_vrf_table_entry_del(self, table_id):
        try:
            # with any del of vrf map, we need to force sync to disk
            self.iproute2_vrf_map_sync_to_disk = True
            del self.iproute2_vrf_map[int(table_id)]
        except Exception, e:
            self.logger.info('vrf: iproute2 vrf map del failed for %d (%s)'
                             %(table_id, str(e)))
            pass

    def _is_vrf_dev(self, ifacename):
        # Look at iproute2 map for now.
        # If it was a master we knew about,
        # it is definately there
        if ifacename in self.iproute2_vrf_map.values():
            return True
        return False

    def _is_dhcp_slave(self, ifaceobj):
        if (not ifaceobj.addr_method or
            (ifaceobj.addr_method != 'dhcp' and
             ifaceobj.addr_method != 'dhcp6')):
                return False
        return True

    def _up_vrf_slave_without_master(self, ifacename, vrfname, ifaceobj,
                                      ifaceobj_getfunc):
        """ If we have a vrf slave that has dhcp configured, bring up the
            vrf master now. This is needed because vrf has special handling
            in dhclient hook which requires the vrf master to be present """

        vrf_master = ifaceobj.upperifaces[0]
        if not vrf_master:
            self.logger.warn('%s: vrf master not found' %ifacename)
            return
        if os.path.exists('/sys/class/net/%s' %vrf_master):
            self.logger.info('%s: vrf master %s exists returning'
                             %(ifacename, vrf_master))
            return
        vrf_master_objs = ifaceobj_getfunc(vrf_master)
        if not vrf_master_objs:
            self.logger.warn('%s: vrf master ifaceobj not found' %ifacename)
            return
        self.logger.info('%s: bringing up vrf master %s'
                         %(ifacename, vrf_master))
        for mobj in vrf_master_objs:
            vrf_table = mobj.get_attr_value_first('vrf-table')
            if vrf_table:
                if vrf_table == 'auto':
                    vrf_table = self._get_avail_vrf_table_id()
                    if not vrf_table:
                        self.log_error('%s: unable to get an auto table id'
                                       %mobj.name)
                    self.logger.info('%s: table id auto: selected table id %s\n'
                                     %(mobj.name, vrf_table))
                try:
                    self._up_vrf_dev(mobj, vrf_table, False)
                except Exception:
                    raise
                break
        self._handle_existing_connections(ifaceobj, vrfname)
        self.ipcmd.link_set(ifacename, 'master', vrfname)
        return

    def _down_dhcp_slave(self, ifaceobj, vrfname):
        try:
            dhclient_cmd_prefix = None
            if (vrfname and self.vrf_exec_cmd_prefix and
                self.ipcmd.link_exists(vrfname)):
                dhclient_cmd_prefix = '%s %s' %(self.vrf_exec_cmd_prefix,
                                                vrfname)
            self.dhclientcmd.release(ifaceobj.name, dhclient_cmd_prefix)
        except:
            # ignore any dhclient release errors
            pass

    def _handle_existing_connections(self, ifaceobj, vrfname):
        if not ifaceobj or ifupdownflags.flags.PERFMODE:
            return
        if (self.vrf_mgmt_devname and
            self.vrf_mgmt_devname == vrfname):
            self._kill_ssh_connections(ifaceobj.name)
        if self._is_dhcp_slave(ifaceobj):
            self._down_dhcp_slave(ifaceobj, vrfname)

    def _up_vrf_slave(self, ifacename, vrfname, ifaceobj=None,
                      ifaceobj_getfunc=None, vrf_exists=False):
        try:
            if vrf_exists or self.ipcmd.link_exists(vrfname):
                upper = self.ipcmd.link_get_upper(ifacename)
                if not upper or upper != vrfname:
                    self._handle_existing_connections(ifaceobj, vrfname)
                    self.ipcmd.link_set(ifacename, 'master', vrfname)
            elif ifaceobj:
                self._up_vrf_slave_without_master(ifacename, vrfname, ifaceobj,
                                                  ifaceobj_getfunc)
            rtnetlink_api.rtnl_api.link_set(ifacename, "up")
        except Exception, e:
            self.log_error('%s: %s' %(ifacename, str(e)))

    def _del_vrf_rules(self, vrf_dev_name, vrf_table):
        pref = 200
        ip_rule_out_format = '%s: from all %s %s lookup %s'
        ip_rule_cmd = 'ip %s rule del pref %s %s %s table %s' 

        rule = ip_rule_out_format %(pref, 'oif', vrf_dev_name, vrf_dev_name)
        if rule in self.ip_rule_cache:
            rule_cmd = ip_rule_cmd %('', pref, 'oif', vrf_dev_name,
                                     vrf_dev_name)
            self.exec_command(rule_cmd)

        rule = ip_rule_out_format %(pref, 'iif', vrf_dev_name, vrf_dev_name)
        if rule in self.ip_rule_cache:
            rule_cmd = ip_rule_cmd %('', pref, 'iif', vrf_dev_name,
                                     vrf_dev_name)
            self.exec_command(rule_cmd)

        rule = ip_rule_out_format %(pref, 'oif', vrf_dev_name, vrf_dev_name)
        if rule in self.ip6_rule_cache:
            rule_cmd = ip_rule_cmd %('-6', pref, 'oif', vrf_dev_name,
                                     vrf_dev_name)
            self.exec_command(rule_cmd)

        rule = ip_rule_out_format %(pref, 'iif', vrf_dev_name, vrf_dev_name)
        if rule in self.ip6_rule_cache:
            rule_cmd = ip_rule_cmd %('-6', pref, 'iif', vrf_dev_name,
                                     vrf_dev_name)
            self.exec_command(rule_cmd)

    def _add_vrf_rules(self, vrf_dev_name, vrf_table):
        pref = 200
        ip_rule_out_format = '%s: from all %s %s lookup %s'
        ip_rule_cmd = 'ip %s rule add pref %s %s %s table %s' 
        if self.vrf_fix_local_table:
            self.vrf_fix_local_table = False
            rule = '0: from all lookup local'
            if rule in self.ip_rule_cache:
                try:
                    self.exec_command('ip rule del pref 0')
                    self.exec_command('ip rule add pref 32765 table local')
                except Exception, e:
                    self.logger.info('%s' %str(e))
                    pass
            if rule in self.ip6_rule_cache:
                try:
                    self.exec_command('ip -6 rule del pref 0')
                    self.exec_command('ip -6 rule add pref 32765 table local')
                except Exception, e:
                    self.logger.info('%s' %str(e))
                    pass

        #Example ip rule
        #200: from all oif blue lookup blue
        #200: from all iif blue lookup blue

        rule = ip_rule_out_format %(pref, 'oif', vrf_dev_name, vrf_dev_name)
        if rule not in self.ip_rule_cache:
            rule_cmd = ip_rule_cmd %('', pref, 'oif', vrf_dev_name,
                                     vrf_dev_name)
            self.exec_command(rule_cmd)

        rule = ip_rule_out_format %(pref, 'iif', vrf_dev_name, vrf_dev_name)
        if rule not in self.ip_rule_cache:
            rule_cmd = ip_rule_cmd %('', pref, 'iif', vrf_dev_name,
                                     vrf_dev_name)
            self.exec_command(rule_cmd)

        rule = ip_rule_out_format %(pref, 'oif', vrf_dev_name, vrf_dev_name)
        if rule not in self.ip6_rule_cache:
            rule_cmd = ip_rule_cmd %('-6', pref, 'oif', vrf_dev_name,
                                     vrf_dev_name)
            self.exec_command(rule_cmd)

        rule = ip_rule_out_format %(pref, 'iif', vrf_dev_name, vrf_dev_name)
        if rule not in self.ip6_rule_cache:
            rule_cmd = ip_rule_cmd %('-6', pref, 'iif', vrf_dev_name,
                                     vrf_dev_name)
            self.exec_command(rule_cmd)

    def _add_vrf_slaves(self, ifaceobj, ifaceobj_getfunc=None):
        running_slaves = self.ipcmd.link_get_lowers(ifaceobj.name)
        config_slaves = ifaceobj.lowerifaces
        if not config_slaves and not running_slaves:
            return

        if not config_slaves: config_slaves = []
        if not running_slaves: running_slaves = []
        add_slaves = set(config_slaves).difference(set(running_slaves))
        del_slaves = set(running_slaves).difference(set(config_slaves))
        if add_slaves:
            for s in add_slaves:
                try:
                    sobj = None
                    if ifaceobj_getfunc:
                        sobj = ifaceobj_getfunc(s)
                    self._up_vrf_slave(s, ifaceobj.name,
                                       sobj[0] if sobj else None,
                                       ifaceobj_getfunc, True)
                except Exception, e:
                    self.logger.info('%s: %s' %(ifaceobj.name, str(e)))

        if del_slaves:
            for s in del_slaves:
                try:
                    sobj = None
                    if ifaceobj_getfunc:
                        sobj = ifaceobj_getfunc(s)
                    self._down_vrf_slave(s, sobj[0] if sobj else None,
                                         ifaceobj.name)
                except Exception, e:
                    self.logger.info('%s: %s' %(ifaceobj.name, str(e)))

        if ifaceobj.link_type == ifaceLinkType.LINK_MASTER:
            for s in config_slaves:
                try:
                    rtnetlink_api.rtnl_api.link_set(s, "up")
                except Exception, e:
                    self.logger.debug('%s: %s: link set up (%s)'
                                      %(ifaceobj.name, s, str(e)))
                    pass

    def _set_vrf_dev_processed_flag(self, ifaceobj):
        ifaceobj.module_flags[self.name] = \
                             ifaceobj.module_flags.setdefault(self.name, 0) | \
                                        vrfPrivFlags.PROCESSED

    def _check_vrf_dev_processed_flag(self, ifaceobj):
        if (ifaceobj.module_flags.get(self.name, 0) & vrfPrivFlags.PROCESSED):
            return True
        return False

    def _create_vrf_dev(self, ifaceobj, vrf_table):
        if not self.ipcmd.link_exists(ifaceobj.name):
            if ifaceobj.name in self.system_reserved_rt_tables.values():
                self.log_error('cannot use system reserved %s vrf names'
                                %( str(self.system_reserved_rt_tables.values())))
            if self.vrf_count == self.vrf_max_count:
                self.log_error('%s: max vrf count %d hit...not '
                               'creating vrf' %(ifaceobj.name,
                                                self.vrf_count))
            if vrf_table == 'auto':
                vrf_table = self._get_avail_vrf_table_id()
                if not vrf_table:
                    self.log_error('%s: unable to get an auto table id'
                                   %ifaceobj.name)
                self.logger.info('%s: table id auto: selected table id %s\n'
                                 %(ifaceobj.name, vrf_table))
            else:
                self._iproute2_is_vrf_tableid_inuse(ifaceobj.name, vrf_table)
                if ifaceobj.name in self.system_reserved_rt_tables.keys():
                    self.log_error('cannot use system reserved %s table ids'
                                  %(str(self.system_reserved_rt_tables.keys())))

            if not vrf_table.isdigit():
                self.log_error('%s: vrf-table must be an integer or \'auto\''
                               %(ifaceobj.name), ifaceobj)

            # XXX: If we decide to not allow vrf id usages out of
            # the reserved ifupdown range, then uncomment this code.
            else:
                if (int(vrf_table) < self.vrf_table_id_start or
                    int(vrf_table) > self.vrf_table_id_end):
                    self.log_error('%s: vrf table id %s out of reserved range [%d,%d]'
                                   %(ifaceobj.name, vrf_table,
                                     self.vrf_table_id_start,
                                     self.vrf_table_id_end))
            try:
                self.ipcmd.link_create(ifaceobj.name, 'vrf',
                                       {'table' : '%s' %vrf_table})
            except Exception, e:
                self.log_error('%s: create failed (%s)\n'
                               %(ifaceobj.name, str(e)))
            if vrf_table != 'auto':
                self._iproute2_vrf_table_entry_add(ifaceobj.name, vrf_table)
        else:
            if vrf_table == 'auto':
                vrf_table = self._get_iproute2_vrf_table(ifaceobj.name)
                if not vrf_table:
                    self.log_error('%s: unable to get vrf table id'
                                   %ifaceobj.name)

            # if the device exists, check if table id is same
            vrfdev_attrs = self.ipcmd.link_get_linkinfo_attrs(ifaceobj.name)
            if vrfdev_attrs:
                running_table = vrfdev_attrs.get('table', None)
                if vrf_table != running_table:
                    self.log_error('%s: cannot change vrf table id,running table id %s is different from config id %s' %(ifaceobj.name,
                                         running_table, vrf_table))
        return vrf_table

    def _up_vrf_helper(self, ifaceobj, vrf_table):
        mode = ""
        if ifupdownflags.flags.PERFMODE:
            mode = "boot"
        if self.vrf_helper:
            self.exec_command('%s create %s %s %s' %(self.vrf_helper,
                              ifaceobj.name, vrf_table, mode))

    def _up_vrf_dev(self, ifaceobj, vrf_table, add_slaves=True,
                    ifaceobj_getfunc=None):

        # if vrf dev is already processed return. This can happen
        # if we the slave was configured before.
        # see self._up_vrf_slave_without_master
        if self._check_vrf_dev_processed_flag(ifaceobj):
            return True

        try:
            vrf_table = self._create_vrf_dev(ifaceobj, vrf_table)
        except Exception, e:
            self.log_error('%s: %s' %(ifaceobj.name, str(e)))
        
        try:
            self._add_vrf_rules(ifaceobj.name, vrf_table)
            self._up_vrf_helper(ifaceobj, vrf_table)
            if add_slaves:
                self._add_vrf_slaves(ifaceobj, ifaceobj_getfunc)
            self._set_vrf_dev_processed_flag(ifaceobj)
            rtnetlink_api.rtnl_api.link_set(ifaceobj.name, "up")
        except Exception, e:
            self.log_error('%s: %s' %(ifaceobj.name, str(e)))

    def _kill_ssh_connections(self, ifacename):
        try:
            runningaddrsdict = self.ipcmd.addr_get(ifacename)
            if not runningaddrsdict:
                return
            iplist = [i.split('/', 1)[0] for i in runningaddrsdict.keys()]
            if not iplist:
                return
            proc=[]
            #Example output:
            #ESTAB      0      0      10.0.1.84:ssh       10.0.1.228:45186     
            #users:(("sshd",pid=2528,fd=3))
            cmdl = ['/bin/ss', '-t', '-p']
            for line in subprocess.check_output(cmdl, stderr=subprocess.STDOUT,
                                                shell=False).splitlines():
                citems = line.split()
                addr = None
                if '%' in citems[3]:
                    addr = citems[3].split('%')[0]
                elif ':ssh' in citems[3]:
                    addr = citems[3].split(':')[0]
                if not addr:
                    continue
                if addr in iplist:
                    if len(citems) == 6:
                        proc.append(citems[5].split(',')[1].split('=')[1])

            if not proc:
                return
            pid = subprocess.check_output(['/bin/ps', '--no-headers',
                                           '-fp', str(os.getppid())],
                                           stderr=subprocess.STDOUT,
                                           shell=False).split()[2]
            self.logger.info("%s: killing active ssh sessions: %s"
                             %(ifacename, str(proc)))
            for id in proc:
                if id != pid:
                    try:
                        os.kill(int(id), signal.SIGINT)
                    except OSError as e:
                        continue

            # Kill current SSH client
            if pid in proc:
                try:
                    forkret = os.fork()
                except OSError, e:
                    self.logger.info("fork error : %s [%d]" % (e.strerror, e.errno))
                if (forkret == 0):  # The first child.
                    try:
                        os.setsid()
                        self.logger.info("%s: ifreload continuing in the background" %ifacename)
                    except OSError, (err_no, err_message):
                        self.logger.info("os.setsid failed: errno=%d: %s" % (err_no, err_message))
                        self.logger.info("pid=%d  pgid=%d" % (os.getpid(), os.getpgid(0)))
                try:
                    self.logger.info("%s: killing our session: %s"
                                     %(ifacename, str(proc)))
                    os.kill(int(pid), signal.SIGINT)
                    return
                except OSError as e:
                    return
        except Exception, e:
            self.logger.info('%s: %s' %(ifacename, str(e)))

    def _up(self, ifaceobj, ifaceobj_getfunc=None):
        try:
            vrf_table = ifaceobj.get_attr_value_first('vrf-table')
            if vrf_table:
                self._iproute2_vrf_map_initialize()
                # This is a vrf device
                self._up_vrf_dev(ifaceobj, vrf_table, True, ifaceobj_getfunc)
            else:
                vrf = ifaceobj.get_attr_value_first('vrf')
                if vrf:
                    self._iproute2_vrf_map_initialize()
                    # This is a vrf slave
                    self._up_vrf_slave(ifaceobj.name, vrf, ifaceobj,
                                       ifaceobj_getfunc)
                else:
                    # check if we were a slave before
                    master = self.ipcmd.link_get_master(ifaceobj.name)
                    if master:
                        self._iproute2_vrf_map_initialize()
                        if self._is_vrf_dev(master):
                            self._down_vrf_slave(ifaceobj.name, ifaceobj,
                                                 master)
        except Exception, e:
            self.log_error(str(e))

    def _down_vrf_helper(self, ifaceobj, vrf_table):
        mode = ""
        if ifupdownflags.flags.PERFMODE:
            mode = "boot"
        if self.vrf_helper:
            self.exec_command('%s delete %s %s %s' %(self.vrf_helper,
                              ifaceobj.name, vrf_table, mode))

    def _down_vrf_dev(self, ifaceobj, vrf_table, ifaceobj_getfunc=None):

        if vrf_table == 'auto':
            vrf_table = self._get_iproute2_vrf_table(ifaceobj.name)

        running_slaves = self.ipcmd.link_get_lowers(ifaceobj.name)
        if running_slaves:
            for s in running_slaves:
                if ifaceobj_getfunc:
                    sobj = ifaceobj_getfunc(s)
                    try:
                        self._handle_existing_connections(sobj[0]
                                                          if sobj else None,
                                                          ifaceobj.name)
                    except Exception, e:
                        self.logger.info('%s: %s' %(ifaceobj.name, str(e)))
                        pass
                try:
                    self.ipcmd.addr_flush(s)
                    rtnetlink_api.rtnl_api.link_set(s, "down")
                except Exception, e:
                    self.logger.info('%s: %s' %(ifaceobj.name, str(e)))
                    pass

        self._down_vrf_helper(ifaceobj, vrf_table)

        try:
            self._del_vrf_rules(ifaceobj.name, vrf_table)
        except Exception, e:
            self.logger.info('%s: %s' %(ifaceobj.name, str(e)))
            pass

        try:
            self.ipcmd.link_delete(ifaceobj.name)
        except Exception, e:
            self.logger.info('%s: %s' %(ifaceobj.name, str(e)))
            pass

        try:
            self._iproute2_vrf_table_entry_del(vrf_table)
        except Exception, e:
            self.logger.info('%s: %s' %(ifaceobj.name, str(e)))
            pass


    def _down_vrf_slave(self, ifacename, ifaceobj=None, vrfname=None):
        try:
            self._handle_existing_connections(ifaceobj, vrfname)
            self.ipcmd.link_set(ifacename, 'nomaster')
            rtnetlink_api.rtnl_api.link_set(ifacename, "down")
        except Exception, e:
            self.logger.warn('%s: %s' %(ifacename, str(e)))

    def _down(self, ifaceobj, ifaceobj_getfunc=None):
        try:
            vrf_table = ifaceobj.get_attr_value_first('vrf-table')
            if vrf_table:
                self._iproute2_vrf_map_initialize()
                self._down_vrf_dev(ifaceobj, vrf_table, ifaceobj_getfunc)
            else:
                vrf = ifaceobj.get_attr_value_first('vrf')
                if vrf:
                    self._iproute2_vrf_map_initialize()
                    self._down_vrf_slave(ifaceobj.name, ifaceobj, None)
        except Exception, e:
            self.log_warn(str(e))

    def _query_check_vrf_slave(self, ifaceobj, ifaceobjcurr, vrf):
        try:
            master = self.ipcmd.link_get_master(ifaceobj.name)
            if not master or master != vrf:
                ifaceobjcurr.update_config_with_status('vrf', str(master), 1)
            else:
                ifaceobjcurr.update_config_with_status('vrf', master, 0)
        except Exception, e:
            self.log_warn(str(e))

    def _query_check_vrf_dev(self, ifaceobj, ifaceobjcurr, vrf_table):
        try:
            if not self.ipcmd.link_exists(ifaceobj.name):
                self.logger.info('%s: vrf: does not exist' %(ifaceobj.name))
                return
            if vrf_table == 'auto':
                config_table = self._get_iproute2_vrf_table(ifaceobj.name)
            else:
                config_table = vrf_table
            vrfdev_attrs = self.ipcmd.link_get_linkinfo_attrs(ifaceobj.name)
            if not vrfdev_attrs:
                ifaceobjcurr.update_config_with_status('vrf-table', 'None', 1)
                return
            running_table = vrfdev_attrs.get('table')
            if not running_table:
                ifaceobjcurr.update_config_with_status('vrf-table', 'None', 1)
                return
            if config_table != running_table:
                ifaceobjcurr.update_config_with_status('vrf-table',
                                                       running_table, 1)
            else:
                ifaceobjcurr.update_config_with_status('vrf-table',
                                                       running_table, 0)
            if not ifupdownflags.flags.WITHDEFAULTS:
                return
            if self.vrf_helper:
                try:
                    self.exec_command('%s verify %s %s'
                                      %(self.vrf_helper,
                                      ifaceobj.name, config_table))
                    ifaceobjcurr.update_config_with_status('vrf-helper',
                                                           '%s create %s %s'
                                                           %(self.vrf_helper,
                                                           ifaceobj.name,
                                                           config_table), 0)
                except Exception, e:
                    ifaceobjcurr.update_config_with_status('vrf-helper',
                                                           '%s create %s %s'
                                                           %(self.vrf_helper,
                                                           ifaceobj.name,
                                                           config_table), 1)
                    pass
        except Exception, e:
            self.log_warn(str(e))

    def _query_check(self, ifaceobj, ifaceobjcurr):
        try:
            vrf_table = ifaceobj.get_attr_value_first('vrf-table')
            if vrf_table:
                self._iproute2_vrf_map_initialize(writetodisk=False)
                self._query_check_vrf_dev(ifaceobj, ifaceobjcurr, vrf_table)
            else:
                vrf = ifaceobj.get_attr_value_first('vrf')
                if vrf:
                    self._iproute2_vrf_map_initialize(writetodisk=False)
                    self._query_check_vrf_slave(ifaceobj, ifaceobjcurr, vrf)
        except Exception, e:
            self.log_warn(str(e))

    def _query_running(self, ifaceobjrunning, ifaceobj_getfunc=None):
        try:
            kind = self.ipcmd.link_get_kind(ifaceobjrunning.name)
            if kind == 'vrf':
                vrfdev_attrs = self.ipcmd.link_get_linkinfo_attrs(ifaceobjrunning.name)
                if vrfdev_attrs:
                    running_table = vrfdev_attrs.get('table')
                    if running_table:
                        ifaceobjrunning.update_config('vrf-table',
                                                      running_table)
            elif kind == 'vrf_slave':
                vrf = self.ipcmd.link_get_master(ifaceobjrunning.name)
                if vrf:
                    ifaceobjrunning.update_config('vrf', vrf)
        except Exception, e:
            self.log_warn(str(e))

    def _query(self, ifaceobj, **kwargs):
        if not self.vrf_helper:
            return
        if (ifaceobj.link_kind & ifaceLinkKind.VRF):
            ifaceobj.update_config('vrf-helper', '%s %s' %(self.vrf_helper,
                                   ifaceobj.name))

    _run_ops = {'pre-up' : _up,
               'post-down' : _down,
               'query-running' : _query_running,
               'query-checkcurr' : _query_check,
               'query' : _query}

    def get_ops(self):
        """ returns list of ops supported by this module """
        return self._run_ops.keys()

    def _init_command_handlers(self):
        if not self.ipcmd:
            self.ipcmd = iproute2()
        if not self.bondcmd:
            self.bondcmd = bondutil()
        if not self.dhclientcmd:
            self.dhclientcmd = dhclient()

    def run(self, ifaceobj, operation, query_ifaceobj=None,
            ifaceobj_getfunc=None, **extra_args):
        """ run bond configuration on the interface object passed as argument

        Args:
            **ifaceobj** (object): iface object

            **operation** (str): any of 'pre-up', 'post-down', 'query-checkcurr',
                'query-running'

        Kwargs:
            **query_ifaceobj** (object): query check ifaceobject. This is only
                valid when op is 'query-checkcurr'. It is an object same as
                ifaceobj, but contains running attribute values and its config
                status. The modules can use it to return queried running state
                of interfaces. status is success if the running state is same
                as user required state in ifaceobj. error otherwise.
        """
        op_handler = self._run_ops.get(operation)
        if not op_handler:
            return
        self._init_command_handlers()
        if operation == 'query-checkcurr':
            op_handler(self, ifaceobj, query_ifaceobj)
        else:
            op_handler(self, ifaceobj, ifaceobj_getfunc=ifaceobj_getfunc)