dhcp-server: T3672: only one failover peer is supported

2 files changed, 39 insertions, 22 deletions

diff --git a/src/conf_mode/dhcp_server.py b/src/conf_mode/dhcp_server.py
index 8d6cef8b7..5b3809017 100755
--- a/src/conf_mode/dhcp_server.py
+++ b/src/conf_mode/dhcp_server.py
@@ -148,9 +148,9 @@ def verify(dhcp):
                           'At least one DHCP shared network must be configured.')
 
     # Inspect shared-network/subnet
-    failover_names = []
     listen_ok = False
     subnets = []
+    failover_ok = False
 
     # A shared-network requires a subnet definition
     for network, network_config in dhcp['shared_network_name'].items():
@@ -159,11 +159,19 @@ def verify(dhcp):
                               'lease subnet must be configured.')
 
         for subnet, subnet_config in network_config['subnet'].items():
+            # All delivered static routes require a next-hop to be set
             if 'static_route' in subnet_config:
                 for route, route_option in subnet_config['static_route'].items():
                     if 'next_hop' not in route_option:
                         raise ConfigError(f'DHCP static-route "{route}" requires router to be defined!')
 
+            # DHCP failover needs at least one subnet that uses it
+            if 'enable_failover' in subnet_config:
+                if 'failover' not in dhcp:
+                    raise ConfigError(f'Can not enable failover for "{subnet}" in "{network}".\n' \
+                                      'Failover is not configured globally!')
+                failover_ok = True
+
             # Check if DHCP address range is inside configured subnet declaration
             if 'range' in subnet_config:
                 networks = []
@@ -192,23 +200,6 @@ def verify(dhcp):
                     tmp = IPRange(range_config['start'], range_config['stop'])
                     networks.append(tmp)
 
-            if 'failover' in subnet_config:
-                for key in ['local_address', 'peer_address', 'name', 'status']:
-                    if key not in subnet_config['failover']:
-                        raise ConfigError(f'Missing DHCP failover parameter "{key}"!')
-
-                # Failover names must be uniquie
-                if subnet_config['failover']['name'] in failover_names:
-                    name = subnet_config['failover']['name']
-                    raise ConfigError(f'DHCP failover names must be unique:\n' \
-                                      f'{name} has already been configured!')
-                failover_names.append(subnet_config['failover']['name'])
-
-                # Failover requires start/stop ranges for pool
-                if 'range' not in subnet_config:
-                    raise ConfigError(f'DHCP failover requires at least one start-stop range to be configured\n'\
-                                      f'within shared-network "{network}, {subnet}" for using failover!')
-
             # Exclude addresses must be in bound
             if 'exclude' in subnet_config:
                 for exclude in subnet_config['exclude']:
@@ -252,6 +243,15 @@ def verify(dhcp):
                     if net.overlaps(net2):
                         raise ConfigError('Conflicting subnet ranges: "{net}" overlaps "{net2}"!')
 
+    if 'failover' in dhcp:
+        if not failover_ok:
+            raise ConfigError('DHCP failover must be enabled for at least one subnet!')
+
+        for key in ['source_address', 'remote', 'status']:
+            if key not in dhcp['failover']:
+                tmp = key.replace('_', '-')
+                raise ConfigError(f'DHCP failover requires "{tmp}" to be specified!')
+
     for address in (dict_search('listen_address', dhcp) or []):
         if is_addr_assigned(address):
             listen_ok = True
diff --git a/src/migration-scripts/dhcp-server/5-to-6 b/src/migration-scripts/dhcp-server/5-to-6
index 7f447ac17..39bbb9f50 100755
--- a/src/migration-scripts/dhcp-server/5-to-6
+++ b/src/migration-scripts/dhcp-server/5-to-6
@@ -29,16 +29,16 @@ file_name = sys.argv[1]
 with open(file_name, 'r') as f:
     config_file = f.read()
 
-base = ['service', 'dhcp-server', 'shared-network-name']
+base = ['service', 'dhcp-server']
 config = ConfigTree(config_file)
 
-if not config.exists(base):
+if not config.exists(base + ['shared-network-name']):
     # Nothing to do
     exit(0)
 
 # Run this for every instance if 'shared-network-name'
-for network in config.list_nodes(base):
-    base_network = base + [network]
+for network in config.list_nodes(base + ['shared-network-name']):
+    base_network = base + ['shared-network-name', network]
 
     if not config.exists(base_network + ['subnet']):
         continue
@@ -60,6 +60,23 @@ for network in config.list_nodes(base):
         if config.exists(base_subnet + ['dns-server']):
             config.rename(base_subnet + ['dns-server'], 'name-server')
 
+
+        # T3672: ISC DHCP server only supports one failover peer
+        if config.exists(base_subnet + ['failover']):
+            # There can only be one failover configuration, if none is present
+            # we add the first one
+            if not config.exists(base + ['failover']):
+                local = config.return_value(base_subnet + ['failover', 'local-address'])
+                remote = config.return_value(base_subnet + ['failover', 'peer-address'])
+                status = config.return_value(base_subnet + ['failover', 'status'])
+
+                config.set(base + ['failover', 'remote'], value=remote)
+                config.set(base + ['failover', 'source-address'], value=local)
+                config.set(base + ['failover', 'status'], value=status)
+
+            config.delete(base_subnet + ['failover'])
+            config.set(base_subnet + ['enable-failover'])
+
 try:
     with open(file_name, 'w') as f:
         f.write(config.to_string())