dhcpv6-server: T5993: Add subnet `interface` node, link subnet to locally connected interfaces

Prior dhcpd behaviour implicitly handled requests for locally connected subnets. Kea requires an explicit link between subnets and an interface.

1 files changed, 68 insertions, 0 deletions

diff --git a/src/migration-scripts/dhcpv6-server/4-to-5 b/src/migration-scripts/dhcpv6-server/4-to-5
new file mode 100755
index 000000000..e808edbe0
--- /dev/null
+++ b/src/migration-scripts/dhcpv6-server/4-to-5
@@ -0,0 +1,68 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2024 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/>.
+
+# T5993: Check if subnet is locally accessible and assign interface to subnet
+
+import sys
+from ipaddress import ip_network
+from vyos.configtree import ConfigTree
+
+if (len(sys.argv) < 1):
+    print("Must specify file name!")
+    sys.exit(1)
+
+file_name = sys.argv[1]
+
+with open(file_name, 'r') as f:
+    config_file = f.read()
+
+base = ['service', 'dhcpv6-server', 'shared-network-name']
+config = ConfigTree(config_file)
+
+if not config.exists(base):
+    # Nothing to do
+    exit(0)
+
+def find_subnet_interface(subnet):
+    subnet_net = ip_network(subnet)
+
+    for iftype in config.list_nodes(['interfaces']):
+        for ifname in config.list_nodes(['interfaces', iftype]):
+            if_base = ['interfaces', iftype, ifname]
+
+            if config.exists(if_base + ['address']):
+                for addr in config.return_values(if_base + ['address']):
+                    if ip_network(addr, strict=False) == subnet_net:
+                        return ifname
+
+    return False
+
+for network in config.list_nodes(base):
+    if not config.exists(base + [network, 'subnet']):
+        continue
+
+    for subnet in config.list_nodes(base + [network, 'subnet']):
+        subnet_interface = find_subnet_interface(subnet)
+
+        if subnet_interface:
+            config.set(base + [network, 'subnet', subnet, 'interface'], value=subnet_interface)
+
+try:
+    with open(file_name, 'w') as f:
+        f.write(config.to_string())
+except OSError as e:
+    print("Failed to save the modified config: {}".format(e))
+    exit(1)