#!/usr/bin/env python3 # # Copyright (C) 2022 VyOS maintainers and contributors # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License version 2 or later as # published by the Free Software Foundation. # # 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, see . import argparse import json import subprocess import socket import time from vyos.util import rc_cmd from pathlib import Path from systemd import journal my_name = Path(__file__).stem def get_best_route_options(route, debug=False): """ Return current best route ('gateway, interface, metric) % get_best_route_options('203.0.113.1') ('192.168.0.1', 'eth1', 1) % get_best_route_options('203.0.113.254') (None, None, None) """ rc, data = rc_cmd(f'ip --detail --json route show protocol failover {route}') if rc == 0: data = json.loads(data) if len(data) == 0: print(f'\nRoute {route} for protocol failover was not found') return None, None, None # Fake metric 999 by default # Search route with the lowest metric best_metric = 999 for entry in data: if debug: print('\n', entry) metric = entry.get('metric') gateway = entry.get('gateway') iface = entry.get('dev') if metric < best_metric: best_metric = metric best_gateway = gateway best_interface = iface if debug: print(f'### Best_route exists: {route}, best_gateway: {best_gateway}, ' f'best_metric: {best_metric}, best_iface: {best_interface}') return best_gateway, best_interface, best_metric def is_port_open(ip, port): """ Check connection to remote host and port Return True if host alive % is_port_open('example.com', 8080) True """ s = socket.socket(socket.AF_INET, socket.SOCK_STREAM, socket.IPPROTO_TCP) s.settimeout(2) try: s.connect((ip, int(port))) s.shutdown(socket.SHUT_RDWR) return True except: return False finally: s.close() def is_target_alive(target=None, iface='', proto='icmp', port=None, debug=False): """ Host availability check by ICMP, ARP, TCP Return True if target checks is successful % is_target_alive('192.0.2.1', 'eth1', proto='arp') True """ if iface != '': iface = f'-I {iface}' if proto == 'icmp': command = f'/usr/bin/ping -q {target} {iface} -n -c 2 -W 1' rc, response = rc_cmd(command) if debug: print(f' [ CHECK-TARGET ]: [{command}] -- return-code [RC: {rc}]') if rc == 0: return True elif proto == 'arp': command = f'/usr/bin/arping -b -c 2 -f -w 1 -i 1 {iface} {target}' rc, response = rc_cmd(command) if debug: print(f' [ CHECK-TARGET ]: [{command}] -- return-code [RC: {rc}]') if rc == 0: return True elif proto == 'tcp' and port is not None: return True if is_port_open(target, port) else False else: return False if __name__ == '__main__': # Parse command arguments and get config parser = argparse.ArgumentParser() parser.add_argument('-c', '--config', action='store', help='Path to protocols failover configuration', required=True, type=Path) args = parser.parse_args() try: config_path = Path(args.config) config = json.loads(config_path.read_text()) except Exception as err: print( f'Configuration file "{config_path}" does not exist or malformed: {err}' ) exit(1) # Useful debug info to console, use debug = True # sudo systemctl stop vyos-failover.service # sudo /usr/libexec/vyos/vyos-failover.py --config /run/vyos-failover.conf debug = False while(True): for route, route_config in config.get('route').items(): exists_route = exists_gateway, exists_iface, exists_metric = get_best_route_options(route, debug=debug) for next_hop, nexthop_config in route_config.get('next_hop').items(): conf_iface = nexthop_config.get('interface') conf_metric = int(nexthop_config.get('metric')) port = nexthop_config.get('check').get('port') port_opt = f'port {port}' if port else '' proto = nexthop_config.get('check').get('type') target = nexthop_config.get('check').get('target') timeout = nexthop_config.get('check').get('timeout') # Best route not fonund in the current routing table if exists_route == (None, None, None): if debug: print(f" [NEW_ROUTE_DETECTED] route: [{route}]") # Add route if check-target alive if is_target_alive(target, conf_iface, proto, port, debug=debug): if debug: print(f' [ ADD ] -- ip route add {route} via {next_hop} dev {conf_iface} ' f'metric {conf_metric} proto failover\n###') rc, command = rc_cmd(f'ip route add {route} via {next_hop} dev {conf_iface} ' f'metric {conf_metric} proto failover') # If something is wrong and gateway not added # Example: Error: Next-hop has invalid gateway. if rc !=0: if debug: print(f'{command} -- return-code [RC: {rc}] {next_hop} dev {conf_iface}') else: journal.send(f'ip route add {route} via {next_hop} dev {conf_iface} ' f'metric {conf_metric} proto failover', SYSLOG_IDENTIFIER=my_name) else: if debug: print(f' [ TARGET_FAIL ] target checks fails for [{target}], do nothing') journal.send(f'Check fail for route {route} target {target} proto {proto} ' f'{port_opt}', SYSLOG_IDENTIFIER=my_name) # Route was added, check if the target is alive # We should delete route if check fails only if route exists in the routing table if not is_target_alive(target, conf_iface, proto, port, debug=debug) and \ exists_route != (None, None, None): if debug: print(f'Nexh_hop {next_hop} fail, target not response') print(f' [ DEL ] -- ip route del {route} via {next_hop} dev {conf_iface} ' f'metric {conf_metric} proto failover [DELETE]') rc_cmd(f'ip route del {route} via {next_hop} dev {conf_iface} metric {conf_metric} proto failover') journal.send(f'ip route del {route} via {next_hop} dev {conf_iface} ' f'metric {conf_metric} proto failover', SYSLOG_IDENTIFIER=my_name) time.sleep(int(timeout))