dhcp: T2562: harden implementation for non existing shared-subnets

2 files changed, 56 insertions, 19 deletions

diff --git a/smoketest/scripts/cli/test_service_dhcp-server.py b/smoketest/scripts/cli/test_service_dhcp-server.py
index c9ec9ebc0..db7b2dda4 100755
--- a/smoketest/scripts/cli/test_service_dhcp-server.py
+++ b/smoketest/scripts/cli/test_service_dhcp-server.py
@@ -369,7 +369,7 @@ class TestServiceDHCPServer(unittest.TestCase):
         # commit changes
         self.session.commit()
 
-        # VErify
+        # Verify
         config = read_file(DHCPD_CONF)
         network = address_from_cidr(subnet)
         netmask = netmask_from_cidr(subnet)
@@ -382,5 +382,39 @@ class TestServiceDHCPServer(unittest.TestCase):
         # Check for running process
         self.assertTrue(process_named_running(PROCESS_NAME))
 
+    def test_dhcp_relay_server(self):
+        # Listen on specific address and return DHCP leases from a non
+        # directly connected pool
+        self.session.set(base_path + ['listen-address', router])
+
+        relay_subnet = '10.0.0.0/16'
+        relay_router = inc_ip(relay_subnet, 1)
+
+        range_0_start = '10.0.1.0'
+        range_0_stop  = '10.0.250.255'
+
+        pool = base_path + ['shared-network-name', 'RELAY', 'subnet', relay_subnet]
+        self.session.set(pool + ['default-router', relay_router])
+        self.session.set(pool + ['range', '0', 'start', range_0_start])
+        self.session.set(pool + ['range', '0', 'stop', range_0_stop])
+
+        # commit changes
+        self.session.commit()
+
+        config = read_file(DHCPD_CONF)
+        network = address_from_cidr(subnet)
+        netmask = netmask_from_cidr(subnet)
+        # Check the relay network
+        self.assertIn(f'subnet {network} netmask {netmask}' + r' { }', config)
+
+        relay_network = address_from_cidr(relay_subnet)
+        relay_netmask = netmask_from_cidr(relay_subnet)
+        self.assertIn(f'subnet {relay_network} netmask {relay_netmask}' + r' {', config)
+        self.assertIn(f'option routers {relay_router};', config)
+        self.assertIn(f'range {range_0_start} {range_0_stop};', config)
+
+        # Check for running process
+        self.assertTrue(process_named_running(PROCESS_NAME))
+
 if __name__ == '__main__':
     unittest.main(verbosity=2)
diff --git a/src/conf_mode/dhcp_server.py b/src/conf_mode/dhcp_server.py
index 392a69427..84a8736e8 100755
--- a/src/conf_mode/dhcp_server.py
+++ b/src/conf_mode/dhcp_server.py
@@ -110,24 +110,27 @@ def get_config(config=None):
     # T2665: defaults include lease time per TAG node which need to be added to
     # individual subnet definitions
     default_values = defaults(base + ['shared-network-name', 'subnet'])
-    for network, network_config in (dict_search('shared_network_name', dhcp).items() or {}):
-        for subnet, subnet_config in (dict_search('subnet', network_config).items() or {}):
-            if 'lease' not in subnet_config:
-                dhcp['shared_network_name'][network]['subnet'][subnet] = dict_merge(
-                    default_values, dhcp['shared_network_name'][network]['subnet'][subnet])
-
-            # If exclude IP addresses are defined we need to slice them out of
-            # the defined ranges
-            if {'exclude', 'range'} <= set(subnet_config):
-                new_range_id = 0
-                new_range_dict = {}
-                for r, r_config in subnet_config['range'].items():
-                    for slice in dhcp_slice_range(subnet_config['exclude'], r_config):
-                        new_range_dict.update({new_range_id : slice})
-                        new_range_id +=1
-
-                dhcp['shared_network_name'][network]['subnet'][subnet].update(
-                        {'range' : new_range_dict})
+
+    if 'shared_network_name' in dhcp:
+        for network, network_config in dhcp['shared_network_name'].items():
+            if 'subnet' in network_config:
+                for subnet, subnet_config in network_config['subnet'].items():
+                    if 'lease' not in subnet_config:
+                        dhcp['shared_network_name'][network]['subnet'][subnet] = dict_merge(
+                            default_values, dhcp['shared_network_name'][network]['subnet'][subnet])
+
+                    # If exclude IP addresses are defined we need to slice them out of
+                    # the defined ranges
+                    if {'exclude', 'range'} <= set(subnet_config):
+                        new_range_id = 0
+                        new_range_dict = {}
+                        for r, r_config in subnet_config['range'].items():
+                            for slice in dhcp_slice_range(subnet_config['exclude'], r_config):
+                                new_range_dict.update({new_range_id : slice})
+                                new_range_id +=1
+
+                        dhcp['shared_network_name'][network]['subnet'][subnet].update(
+                                {'range' : new_range_dict})
 
     return dhcp