Store and restore static routes upon DHCP renew

net-dhcp/network.py

@@ -354,6 +354,15 @@ class ContainerDHCPManager:
             elif event_type == udhcpc.EventType.BOUND:
                 logger.info('[dhcp container] BOUND Event %s', _event)
 
+            result = subprocess.run(['nsenter', f'-n{dhcp.netns}', '--', '/sbin/ip', 'route', 'show', 'type', 'unicast', 'proto', 'static', 'table', 'all'], timeout=1, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
+            if result.returncode == 0:
+                routes = result.stdout
+                routes = routes.splitlines()
+                if routes:
+                    logger.info('[dhcp container] Store existing static routes')
+                    for route in routes:
+                        logger.info('[dhcp container] Stored static route: %s', route)
+
             logger.info('[dhcp container] Flushing IP addresses')
             subprocess.check_call(['nsenter', f'-n{dhcp.netns}', '--', '/sbin/ip', 'address', 'flush', 'dev',
                 str(dhcp.iface['ifname']), 'label', str(dhcp.iface['ifname'])],
@@ -369,6 +378,14 @@ class ContainerDHCPManager:
                 subprocess.check_call(['nsenter', f'-n{dhcp.netns}', '--', '/sbin/ip', 'route', 'replace', 'default', 'via',
                     str(dhcp.gateway)],
                     timeout=1, stdin=subprocess.DEVNULL, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+
+            if routes:
+                logger.info('[dhcp container] Restore static routes')
+                for route in routes:
+                    parts = route.split()
+                    command = ['nsenter', f'-n{dhcp.netns}', '--', '/sbin/ip', 'route', 'add'] + parts + ['proto', 'static']
+                    output = subprocess.run(command, timeout=1, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+                    logger.info('[dhcp container] Restored static route: %s', route)
         else:
             logger.info('[dhcp container] Unhandled Event %s: %s', event_type,_event)