dhcp: T3316: Fix `listen-address` handling and add `listen-interface` as supported by Kea

7 files changed, 61 insertions, 5 deletions

diff --git a/data/templates/dhcp-server/kea-dhcp4.conf.j2 b/data/templates/dhcp-server/kea-dhcp4.conf.j2
index 6ab13ab27..629fa952a 100644
--- a/data/templates/dhcp-server/kea-dhcp4.conf.j2
+++ b/data/templates/dhcp-server/kea-dhcp4.conf.j2
@@ -1,8 +1,16 @@
 {
     "Dhcp4": {
         "interfaces-config": {
+{% if listen_address is vyos_defined %}
+            "interfaces": {{ listen_address | kea_address_json }},
+            "dhcp-socket-type": "udp",
+{% elif listen_interface is vyos_defined %}
+            "interfaces": {{ listen_interface | tojson }},
+            "dhcp-socket-type": "raw",
+{% else %}
             "interfaces": [ "*" ],
             "dhcp-socket-type": "raw",
+{% endif %}
             "service-sockets-max-retries": 5,
             "service-sockets-retry-wait-time": 5000
         },
diff --git a/interface-definitions/include/listen-interface-multi-broadcast.xml.i b/interface-definitions/include/listen-interface-multi-broadcast.xml.i
new file mode 100644
index 000000000..b3d5a3ecc
--- /dev/null
+++ b/interface-definitions/include/listen-interface-multi-broadcast.xml.i
@@ -0,0 +1,18 @@
+<!-- include start from listen-interface-multi-broadcast.xml.i -->
+<leafNode name="listen-interface">
+  <properties>
+    <help>Interface for DHCP Relay Agent to listen for requests</help>
+    <completionHelp>
+      <script>${vyos_completion_dir}/list_interfaces --broadcast</script>
+    </completionHelp>
+    <valueHelp>
+      <format>txt</format>
+      <description>Interface name</description>
+    </valueHelp>
+    <constraint>
+      #include <include/constraint/interface-name.xml.i>
+    </constraint>
+    <multi/>
+  </properties>
+</leafNode>
+<!-- include end -->
diff --git a/interface-definitions/service_dhcp-server.xml.in b/interface-definitions/service_dhcp-server.xml.in
index a5cee62d1..27485b6d4 100644
--- a/interface-definitions/service_dhcp-server.xml.in
+++ b/interface-definitions/service_dhcp-server.xml.in
@@ -74,6 +74,7 @@
             </properties>
           </leafNode>
           #include <include/listen-address-ipv4.xml.i>
+          #include <include/listen-interface-multi-broadcast.xml.i>
           <tagNode name="shared-network-name">
             <properties>
               <help>Name of DHCP shared network</help>
diff --git a/python/vyos/template.py b/python/vyos/template.py
index c0c09f690..1368f1f61 100644
--- a/python/vyos/template.py
+++ b/python/vyos/template.py
@@ -786,6 +786,23 @@ def range_to_regex(num_range):
     regex = range_to_regex(num_range)
     return f'({regex})'
 
+@register_filter('kea_address_json')
+def kea_address_json(addresses):
+    from json import dumps
+    from vyos.utils.network import is_addr_assigned
+
+    out = []
+
+    for address in addresses:
+        ifname = is_addr_assigned(address, return_ifname=True)
+
+        if not ifname:
+            continue
+
+        out.append(f'{ifname}/{address}')
+
+    return dumps(out)
+
 @register_filter('kea_failover_json')
 def kea_failover_json(config):
     from json import dumps
diff --git a/python/vyos/utils/network.py b/python/vyos/utils/network.py
index 997ee6309..b782e0bd8 100644
--- a/python/vyos/utils/network.py
+++ b/python/vyos/utils/network.py
@@ -308,7 +308,7 @@ def is_ipv6_link_local(addr):
 
     return False
 
-def is_addr_assigned(ip_address, vrf=None) -> bool:
+def is_addr_assigned(ip_address, vrf=None, return_ifname=False) -> bool | str:
     """ Verify if the given IPv4/IPv6 address is assigned to any interface """
     from netifaces import interfaces
     from vyos.utils.network import get_interface_config
@@ -323,7 +323,7 @@ def is_addr_assigned(ip_address, vrf=None) -> bool:
             continue
 
         if is_intf_addr_assigned(interface, ip_address):
-            return True
+            return interface if return_ifname else True
 
     return False
 
diff --git a/smoketest/scripts/cli/test_service_dhcp-server.py b/smoketest/scripts/cli/test_service_dhcp-server.py
index 99ac406cd..ef6191fb1 100755
--- a/smoketest/scripts/cli/test_service_dhcp-server.py
+++ b/smoketest/scripts/cli/test_service_dhcp-server.py
@@ -32,6 +32,7 @@ CTRL_PROCESS_NAME = 'kea-ctrl-agent'
 KEA4_CONF = '/run/kea/kea-dhcp4.conf'
 KEA4_CTRL = '/run/kea/dhcp4-ctrl-socket'
 base_path = ['service', 'dhcp-server']
+interface = 'dum8765'
 subnet = '192.0.2.0/25'
 router = inc_ip(subnet, 1)
 dns_1 = inc_ip(subnet, 2)
@@ -46,11 +47,11 @@ class TestServiceDHCPServer(VyOSUnitTestSHIM.TestCase):
         cls.cli_delete(cls, base_path)
 
         cidr_mask = subnet.split('/')[-1]
-        cls.cli_set(cls, ['interfaces', 'dummy', 'dum8765', 'address', f'{router}/{cidr_mask}'])
+        cls.cli_set(cls, ['interfaces', 'dummy', interface, 'address', f'{router}/{cidr_mask}'])
 
     @classmethod
     def tearDownClass(cls):
-        cls.cli_delete(cls, ['interfaces', 'dummy', 'dum8765'])
+        cls.cli_delete(cls, ['interfaces', 'dummy', interface])
         super(TestServiceDHCPServer, cls).tearDownClass()
 
     def tearDown(self):
@@ -95,6 +96,8 @@ class TestServiceDHCPServer(VyOSUnitTestSHIM.TestCase):
         range_1_start = inc_ip(subnet, 40)
         range_1_stop  = inc_ip(subnet, 50)
 
+        self.cli_set(base_path + ['listen-interface', interface])
+
         pool = base_path + ['shared-network-name', shared_net_name, 'subnet', subnet]
         # we use the first subnet IP address as default gateway
         self.cli_set(pool + ['option', 'default-router', router])
@@ -116,6 +119,7 @@ class TestServiceDHCPServer(VyOSUnitTestSHIM.TestCase):
         config = read_file(KEA4_CONF)
         obj = loads(config)
 
+        self.verify_config_value(obj, ['Dhcp4', 'interfaces-config'], 'interfaces', [interface])
         self.verify_config_value(obj, ['Dhcp4', 'shared-networks'], 'name', shared_net_name)
         self.verify_config_value(obj, ['Dhcp4', 'shared-networks', 0, 'subnet4'], 'subnet', subnet)
         self.verify_config_value(obj, ['Dhcp4', 'shared-networks', 0, 'subnet4'], 'valid-lifetime', 86400)
@@ -607,6 +611,7 @@ class TestServiceDHCPServer(VyOSUnitTestSHIM.TestCase):
         config = read_file(KEA4_CONF)
         obj = loads(config)
 
+        self.verify_config_value(obj, ['Dhcp4', 'interfaces-config'], 'interfaces', [f'{interface}/{router}'])
         self.verify_config_value(obj, ['Dhcp4', 'shared-networks'], 'name', 'RELAY')
         self.verify_config_value(obj, ['Dhcp4', 'shared-networks', 0, 'subnet4'], 'subnet', relay_subnet)
 
diff --git a/src/conf_mode/service_dhcp-server.py b/src/conf_mode/service_dhcp-server.py
index 7ebc560ba..329e18993 100755
--- a/src/conf_mode/service_dhcp-server.py
+++ b/src/conf_mode/service_dhcp-server.py
@@ -31,6 +31,7 @@ from vyos.utils.file import chmod_775
 from vyos.utils.file import makedir
 from vyos.utils.file import write_file
 from vyos.utils.process import call
+from vyos.utils.network import interface_exists
 from vyos.utils.network import is_subnet_connected
 from vyos.utils.network import is_addr_assigned
 from vyos import ConfigError
@@ -294,12 +295,18 @@ def verify(dhcp):
         else:
             raise ConfigError(f'listen-address "{address}" not configured on any interface')
 
-
     if not listen_ok:
         raise ConfigError('None of the configured subnets have an appropriate primary IP address on any\n'
                           'broadcast interface configured, nor was there an explicit listen-address\n'
                           'configured for serving DHCP relay packets!')
 
+    if 'listen_address' in dhcp and 'listen_interface' in dhcp:
+        raise ConfigError(f'Cannot define listen-address and listen-interface at the same time')
+
+    for interface in (dict_search('listen_interface', dhcp) or []):
+        if not interface_exists(interface):
+            raise ConfigError(f'listen-interface "{interface}" does not exist')
+
     return None
 
 def generate(dhcp):