vland.py

#! /usr/bin/python

#  Copyright 2014 Linaro Limited
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#  MA 02110-1301, USA.
#
#  Main VLANd module
#

import os, sys
import time
import logging

vlandpath = os.path.abspath(os.path.normpath(os.path.dirname(sys.argv[0])))
sys.path.insert(0, vlandpath)

import drivers
from config.config import VlanConfig
from db.db import VlanDB
from ipc.ipc import VlanIpc
from errors import CriticalError, InputError, ConfigError, SocketError
from util import VlanUtil

class DaemonState:
    """ Simple container for stuff to make for nicer syntax """

state = DaemonState()
state.version = "0.2-DEV"
state.banner = "Linaro VLANd version %s" % state.version
state.starttime = time.time()

print '%s' % state.banner

print 'Parsing Config...'
state.config = VlanConfig(filenames=('./vland.cfg',))
print '  Config knows about %d switches' % len(state.config.switches)

util = VlanUtil()

print 'Connecting to DB...'
state.db = VlanDB(db_name=state.config.database.dbname,
                  username=state.config.database.username)

switches = state.db.all_switches()
print '  DB knows about %d switches' % len(switches)
ports = state.db.all_ports()
print '  DB knows about %d ports' % len(ports)
vlans = state.db.all_vlans()
print '  DB knows about %d vlans' % len(vlans)

# Initial startup sanity chacking

# For sanity, we need to know the vlan_id for the default vlan (tag
# 1). Make sure we know that before anybody attempts to create things
# that depend on it.
state.default_vlan_id = state.db.get_vlan_id_by_tag(state.config.vland.default_vlan_tag)
if state.default_vlan_id is None:
    # It doesn't exist - create it and try again
    state.default_vlan_id = state.db.create_vlan("DEFAULT",
                                                 state.config.vland.default_vlan_tag,
                                                 True)

if len(switches) != len(state.config.switches):
    print 'You have configured access details for %d switch(es), ' % len(state.config.switches)
    print 'but have %d switch(es) registered in your database.' % len(switches)
    print 'You must fix this difference for VLANd to work sensibly.'
    print 'HINT: Running admin.py --auto-import-switch <switch_name>'
    print 'for each of your switches may help!'
    print

# Now start up the core loop. Listen for command connections and
# process them
state.running = True
ipc = VlanIpc()
ipc.server_init('localhost', state.config.vland.port)
while state.running:
    try:
        ipc.server_listen()
        json_data = ipc.server_recv()
    except SocketError as e:
        print e
        logging.debug('Caught IPC error, ignoring')
        continue
    except:
        ipc.server_close()
        raise

    logging.debug("client %s sent us:" % json_data['client_name'])
    logging.debug(json_data)

    response = {}

    # Several types of IPC message here, with potentially different
    # access control and safety

    # First - simple queries to the database only. Should be safe!
    if json_data['type'] == 'db_query':
        response['type'] = 'response'
        try:
            response['data'] = util.perform_db_query(state, json_data['command'], json_data['data'])
            response['response'] = 'ACK'
        except InputError as e:
            print e
            response['response'] = 'ERROR'
            response['error'] = e.__str__()

    # Next - simple queries about daemon state only. Should be safe!
    if json_data['type'] == 'daemon_query':
        response['type'] = 'response'
        try:
            response['data'] = util.perform_daemon_query(state, json_data['command'], json_data['data'])
            response['response'] = 'ACK'
        except InputError as e:
            print e
            response['response'] = 'ERROR'
            response['error'] = e.__str__()

    # Next, calls that manipulate objects in the database only
    # (switches and ports). These are safe and don't need actual
    # co-ordinating with hardware directly.
    #
    # As/when/if we add authentication, use of this function will need
    # it.
    if json_data['type'] == 'db_update':
        response['type'] = 'response'
        try:
            response['data'] = util.perform_db_update(state, json_data['command'], json_data['data'])
            response['response'] = 'ACK'
        except InputError as e:
            print e
            response['response'] = 'ERROR'
            response['error'] = e.__str__()

    # Next, calls that may manipulate switch state *as well* as state
    # in the database - changes to VLAN setup.
    #
    # As/when/if we add authentication, use of this function will need
    # it.
    if json_data['type'] == 'vlan_update':
        response['type'] = 'response'
        try:
            response['data'] = util.perform_vlan_update(state, json_data['command'], json_data['data'])
            response['response'] = 'ACK'
        except InputError as e:
            print e
            response['response'] = 'ERROR'
            response['error'] = e.__str__()

    # Finally, IPC interface for more complex API calls.
    # NOT IMPLEMENTED YET
    if json_data['type'] == 'vland_api':
        response['type'] = 'response'
        response['response'] = 'ERROR'
        response['error'] = 'VLANd API not yet implemented...'

    logging.debug("sending reply:")
    logging.debug(response)

    ipc.server_reply(response)

# We've been asked to shut down. Do that as cleanly as we can
ipc.server_close()