Support DHCPv6

net-dhcp/network.py

@@ -17,6 +17,7 @@ from . import NetDhcpError, udhcpc, app
 OPTS_KEY = 'com.docker.network.generic'
 OPT_PREFIX = 'devplayer0.net-dhcp'
 OPT_BRIDGE = f'{OPT_PREFIX}.bridge'
+OPT_IPV6 = f'{OPT_PREFIX}.ipv6'
 
 logger = logging.getLogger('gunicorn.error')
 
@@ -57,7 +58,9 @@ def get_bridges():
 def net_bridge(n):
     return ndb.interfaces[client.networks.get(n).attrs['Options'][OPT_BRIDGE]]
 def ipv6_enabled(n):
-    return client.networks.get(n).attrs['EnableIPv6']
+    options = client.networks.get(n).attrs['Options']
+    return OPT_IPV6 in options and options[OPT_IPV6] == 'true'
+
 def endpoint_container_iface(n, e):
     for cid, info in client.networks.get(n).attrs['Containers'].items():
         if info['EndpointID'] == e:
@@ -99,10 +102,15 @@ def net_get_capabilities():
 @app.route('/NetworkDriver.CreateNetwork', methods=['POST'])
 def create_net():
     req = request.get_json(force=True)
-    if OPT_BRIDGE not in req['Options'][OPTS_KEY]:
+    options = req['Options'][OPTS_KEY]
+    if OPT_BRIDGE not in options:
         return jsonify({'Err': 'No bridge provided'}), 400
+    # We have to use a custom "enable IPv6" option because Docker's null IPAM driver doesn't support IPv6 and a plugin
+    # IPAM driver isn't allowed to return an empty address
+    if OPT_IPV6 in options and options[OPT_IPV6] not in ('', 'true', 'false'):
+        return jsonify({'Err': 'Invalid boolean value for ipv6'}), 400
 
-    desired = req['Options'][OPTS_KEY][OPT_BRIDGE]
+    desired = options[OPT_BRIDGE]
     bridges = get_bridges()
     if desired not in bridges:
         return jsonify({'Err': f'Bridge "{desired}" not found (or the specified bridge is already used by Docker)'}), 400
@@ -156,14 +164,16 @@ def create_endpoint():
                 for bridge_addr in bridge_addrs:
                     if addr.ip == bridge_addr.ip:
                         raise NetDhcpError(400, f'Address {addr} is already in use on bridge {bridge["ifname"]}')
-            elif type_ == 'v4':
-                dhcp = udhcpc.DHCPClient(if_container, once=True)
-                addr = dhcp.finish()
-                res_iface['Address'] = str(addr)
-                gateway_hints[endpoint_id] = dhcp.gateway
             else:
-                raise NetDhcpError(400, f'DHCPv6 is currently unsupported')
-            logger.info('Adding address %s to %s', addr, if_container['ifname'])
+                dhcp = udhcpc.DHCPClient(if_container, v6=type_ == 'v6', once=True)
+                addr = dhcp.finish()
+                if not addr:
+                    return
+                res_iface[k] = str(addr)
+
+                if dhcp.gateway:
+                    gateway_hints[endpoint_id] = dhcp.gateway
+            logger.info('Adding IP%s address %s to %s', type_, addr, if_container['ifname'])
 
         try_addr('v4')
         if ipv6_enabled(network_id):
@@ -236,7 +246,8 @@ def join():
         },
         'StaticRoutes': []
     }
-    if endpoint in gateway_hints and gateway_hints[endpoint]:
+
+    if endpoint in gateway_hints:
         gateway = gateway_hints[endpoint]
         logger.info('Setting IPv4 gateway from DHCP (%s)', gateway)
         res['Gateway'] = str(gateway)
@@ -288,6 +299,7 @@ class ContainerDHCPManager:
         self.ipv6 = ipv6_enabled(network)
 
         self.dhcp = None
+        self.dhcp6 = None
         self._thread = threading.Thread(target=self.run)
         self._thread.start()
 
@@ -323,9 +335,15 @@ class ContainerDHCPManager:
     def run(self):
         try:
             iface = await_endpoint_container_iface(self.network, self.endpoint)
+
             self.dhcp = udhcpc.DHCPClient(iface, event_listener=self._on_event)
-            logger.info('Starting DHCP client on %s in container namespace %s', iface['ifname'], \
+            logger.info('Starting DHCPv4 client on %s in container namespace %s', iface['ifname'], \
                 self.dhcp.netns)
+
+            if self.ipv6:
+                self.dhcp6 = udhcpc.DHCPClient(iface, v6=True, event_listener=self._on_event)
+                logger.info('Starting DHCPv6 client on %s in container namespace %s', iface['ifname'], \
+                    self.dhcp6.netns)
         except Exception as e:
             logger.exception(e)
 
@@ -333,8 +351,14 @@ class ContainerDHCPManager:
         if not self.dhcp:
             return
 
-        logger.info('Shutting down DHCP client on %s in container namespace %s', \
+        logger.info('Shutting down DHCPv4 client on %s in container namespace %s', \
             self.dhcp.iface['ifname'], self.dhcp.netns)
         self.dhcp.finish(timeout=1)
+
+        if self.ipv6:
+            logger.info('Shutting down DHCPv6 client on %s in container namespace %s', \
+                self.dhcp6.iface['ifname'], self.dhcp.netns)
+            self.dhcp6.finish(timeout=1)
+
         ndb.sources.remove(self.dhcp.netns)
         self._thread.join()

net-dhcp/udhcpc.py

@@ -29,8 +29,9 @@ class DHCPClientError(Exception):
 def _nspopen_wrapper(netns):
     return lambda *args, **kwargs: NSPopen(netns, *args, **kwargs)
 class DHCPClient:
-    def __init__(self, iface, once=False, event_listener=None):
+    def __init__(self, iface, v6=False, once=False, event_listener=None):
         self.iface = iface
+        self.v6 = v6
         self.once = once
         self.event_listeners = [DHCPClient._attr_listener]
         if event_listener:
@@ -42,10 +43,12 @@ class DHCPClient:
             logger.debug('udhcpc using netns %s', self.netns)
 
         Popen = _nspopen_wrapper(self.netns) if self.netns else subprocess.Popen
-        cmdline = ['/sbin/udhcpc', '-s', HANDLER_SCRIPT, '-i', iface['ifname'], '-f']
+        bin_path = '/usr/bin/udhcpc6' if v6 else '/sbin/udhcpc'
+        cmdline = [bin_path, '-s', HANDLER_SCRIPT, '-i', iface['ifname'], '-f']
         cmdline.append('-q' if once else '-R')
 
-        self._event_queue = posix_ipc.MessageQueue(f'/udhcpc_{iface["address"].replace(":", "_")}', \
+        self._suffix = '6' if v6 else ''
+        self._event_queue = posix_ipc.MessageQueue(f'/udhcpc{self._suffix}_{iface["address"].replace(":", "_")}', \
             flags=os.O_CREAT | os.O_EXCL)
         self.proc = Popen(cmdline, env={'EVENT_QUEUE': self._event_queue.name})
 
@@ -84,10 +87,10 @@ class DHCPClient:
             try:
                 event['type'] = EventType(event['type'])
             except ValueError:
-                logger.warning('udhcpc#%d unknown event "%s"', self.proc.pid, event)
+                logger.warning('udhcpc%s#%d unknown event "%s"', self._suffix, self.proc.pid, event)
                 continue
 
-            logger.debug('[udhcp#%d event] %s', self.proc.pid, event)
+            logger.debug('[udhcp%s#%d event] %s', self._suffix, self.proc.pid, event)
             for listener in self.event_listeners:
                 try:
                     listener(self, event['type'], event)
@@ -96,7 +99,7 @@ class DHCPClient:
 
     def await_ip(self, timeout=10):
         if not self._has_lease.wait(timeout=timeout):
-            raise DHCPClientError('Timed out waiting for dhcp lease')
+            raise DHCPClientError(f'Timed out waiting for lease from udhcpc{self._suffix}')
 
         return self.ip
 
@@ -105,14 +108,14 @@ class DHCPClient:
             return
 
         if self.proc.returncode != None and (not self.once or self.proc.returncode != 0):
-            raise DHCPClientError(f'udhcpc exited early with code {self.proc.returncode}')
+            raise DHCPClientError(f'udhcpc{self._suffix} exited early with code {self.proc.returncode}')
         if self.once:
             self.await_ip()
         else:
             self.proc.terminate()
 
         if self.proc.wait(timeout=timeout) != 0:
-            raise DHCPClientError(f'udhcpc exited with non-zero exit code {self.proc.returncode}')
+            raise DHCPClientError(f'udhcpc{self._suffix} exited with non-zero exit code {self.proc.returncode}')
         if self.netns:
             self.proc.release()
 

net-dhcp/udhcpc_handler.py

@@ -11,11 +11,14 @@ if __name__ != '__main__':
 
 event = {'type': sys.argv[1]}
 if event['type'] in ('bound', 'renew'):
-    event['ip'] = f'{env["ip"]}/{env["mask"]}'
-    if 'router' in env:
-        event['gateway'] = env['router']
-    if 'domain' in env:
-        event['domain'] = env['domain']
+    if 'ipv6' in env:
+        event['ip'] = env['ipv6']
+    else:
+        event['ip'] = f'{env["ip"]}/{env["mask"]}'
+        if 'router' in env:
+            event['gateway'] = env['router']
+        if 'domain' in env:
+            event['domain'] = env['domain']
 elif event['type'] in ('deconfig', 'leasefail', 'nak'):
     pass
 else: