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Diffstat (limited to 'src/helpers/vyos-failover.py')
| -rwxr-xr-x | src/helpers/vyos-failover.py | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/src/helpers/vyos-failover.py b/src/helpers/vyos-failover.py new file mode 100755 index 000000000..1ac193423 --- /dev/null +++ b/src/helpers/vyos-failover.py @@ -0,0 +1,184 @@ +#!/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 <http://www.gnu.org/licenses/>. + +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)) |