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.

5 files changed, 89 insertions, 1 deletions

diff --git a/interface-definitions/include/version/dhcpv6-server-version.xml.i b/interface-definitions/include/version/dhcpv6-server-version.xml.i
index bfef27b77..1f30368a3 100644
--- a/interface-definitions/include/version/dhcpv6-server-version.xml.i
+++ b/interface-definitions/include/version/dhcpv6-server-version.xml.i
@@ -1,3 +1,3 @@
 <!-- include start from include/version/dhcpv6-server-version.xml.i -->
-<syntaxVersion component='dhcpv6-server' version='4'></syntaxVersion>
+<syntaxVersion component='dhcpv6-server' version='5'></syntaxVersion>
 <!-- include end -->
diff --git a/interface-definitions/service_dhcpv6-server.xml.in b/interface-definitions/service_dhcpv6-server.xml.in
index 28b97a64b..daca7b43f 100644
--- a/interface-definitions/service_dhcpv6-server.xml.in
+++ b/interface-definitions/service_dhcpv6-server.xml.in
@@ -97,6 +97,21 @@
                 </properties>
                 <children>
                   #include <include/dhcp/option-v6.xml.i>
+                  <leafNode name="interface">
+                    <properties>
+                      <help>Optional interface for this subnet to accept requests from</help>
+                      <completionHelp>
+                        <script>${vyos_completion_dir}/list_interfaces</script>
+                      </completionHelp>
+                      <valueHelp>
+                        <format>txt</format>
+                        <description>Interface name</description>
+                      </valueHelp>
+                      <constraint>
+                        #include <include/constraint/interface-name.xml.i>
+                      </constraint>
+                    </properties>
+                  </leafNode>
                   <tagNode name="range">
                     <properties>
                       <help>Parameters setting ranges for assigning IPv6 addresses</help>
diff --git a/python/vyos/kea.py b/python/vyos/kea.py
index 720bebec3..7365c1f02 100644
--- a/python/vyos/kea.py
+++ b/python/vyos/kea.py
@@ -212,6 +212,9 @@ def kea6_parse_subnet(subnet, config):
     if 'option' in config:
         out['option-data'] = kea6_parse_options(config['option'])
 
+    if 'interface' in config:
+        out['interface'] = config['interface']
+
     if 'range' in config:
         pools = []
         for num, range_config in config['range'].items():
diff --git a/smoketest/scripts/cli/test_service_dhcpv6-server.py b/smoketest/scripts/cli/test_service_dhcpv6-server.py
index 5a831b8a0..6ecf6c1cf 100755
--- a/smoketest/scripts/cli/test_service_dhcpv6-server.py
+++ b/smoketest/scripts/cli/test_service_dhcpv6-server.py
@@ -102,6 +102,7 @@ class TestServiceDHCPv6Server(VyOSUnitTestSHIM.TestCase):
         pool = base_path + ['shared-network-name', shared_net_name, 'subnet', subnet]
 
         self.cli_set(base_path + ['preference', preference])
+        self.cli_set(pool + ['interface', interface])
         self.cli_set(pool + ['subnet-id', '1'])
         # we use the first subnet IP address as default gateway
         self.cli_set(pool + ['lease-time', 'default', lease_time])
@@ -146,6 +147,7 @@ class TestServiceDHCPv6Server(VyOSUnitTestSHIM.TestCase):
 
         self.verify_config_value(obj, ['Dhcp6', 'shared-networks'], 'name', shared_net_name)
         self.verify_config_value(obj, ['Dhcp6', 'shared-networks', 0, 'subnet6'], 'subnet', subnet)
+        self.verify_config_value(obj, ['Dhcp6', 'shared-networks', 0, 'subnet6'], 'interface', interface)
         self.verify_config_value(obj, ['Dhcp6', 'shared-networks', 0, 'subnet6'], 'id', 1)
         self.verify_config_value(obj, ['Dhcp6', 'shared-networks', 0, 'subnet6'], 'valid-lifetime', int(lease_time))
         self.verify_config_value(obj, ['Dhcp6', 'shared-networks', 0, 'subnet6'], 'min-valid-lifetime', int(min_lease_time))
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)