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-rwxr-xr-xsrc/helpers/vyos-failover.py184
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))