T913: DHCP relay service XML/Python rewrite for IPv6

1 files changed, 121 insertions, 0 deletions

diff --git a/src/conf_mode/dhcpv6_relay.py b/src/conf_mode/dhcpv6_relay.py
new file mode 100755
index 000000000..982320d18
--- /dev/null
+++ b/src/conf_mode/dhcpv6_relay.py
@@ -0,0 +1,121 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2018 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/>.
+#
+#
+
+import sys
+import os
+import jinja2
+
+from vyos.config import Config
+from vyos import ConfigError
+
+config_file = r'/etc/default/isc-dhcpv6-relay'
+
+# Please be careful if you edit the template.
+config_tmpl = """
+### Autogenerated by dhcpv6_relay.py ###
+
+# Defaults for isc-dhcpv6-relay initscript sourced by /etc/init.d/isc-dhcpv6-relay
+
+OPTIONS="-6 -l {{ listen_addr | join('-l ') }} -p {{ port }} {{ options | join(' ') }} -u {{ upstream_addr | join('-u ') }}"
+"""
+
+default_config_data = {
+    'listen_addr': [],
+    'upstream_addr': [],
+    'port': '547',
+    'options': [],
+}
+
+def get_config():
+    relay = default_config_data
+    conf = Config()
+    if not conf.exists('service dhcpv6-relay'):
+        return None
+    else:
+        conf.set_level('service dhcpv6-relay')
+
+    # Network interfaces/address to listen on for DHCPv6 query(s)
+    if conf.exists('listen-interface'):
+        interfaces = conf.list_nodes('listen-interface')
+        for intf in interfaces:
+            addr = conf.return_value('listen-interface {0} address'.format(intf))
+            listen = addr + '%' + intf
+            relay['listen_addr'].append(listen)
+
+    # Upstream interface/address for remote DHCPv6 server
+    if conf.exists('upstream-interface'):
+        interfaces = conf.list_nodes('upstream-interface')
+        for intf in interfaces:
+            addr = conf.return_value('upstream-interface {0} address'.format(intf))
+            server = addr + '%' + intf
+            relay['upstream_addr'].append(server)
+
+    # Listen and transmit on port <xy>. This is mostly useful for debugging
+    # purposes. Default is port 67 for DHCPv4/BOOTP, or port 547 for DHCPv6.
+    if conf.exists('listen-port'):
+        relay['port'] = conf.return_value('listen-port')
+
+    # Maximum hop count. When forwarding packets, dhcrelay discards packets
+    # which have reached a hop count of COUNT. Default is 10. Maximum is 255.
+    if conf.exists('max-hop-count'):
+        count = '-c ' + conf.return_value('max-hop-count')
+        relay['options'].append(count)
+
+    if conf.exists('use-interface-id-option'):
+        relay['options'].append('-I')
+
+    return relay
+
+def verify(relay):
+    # bail out early - looks like removal from running config
+    if relay is None:
+        return None
+
+    return None
+
+def generate(relay):
+    # bail out early - looks like removal from running config
+    if relay is None:
+        return None
+
+    tmpl = jinja2.Template(config_tmpl)
+    config_text = tmpl.render(relay)
+    with open(config_file, 'w') as f:
+        f.write(config_text)
+
+    return None
+
+def apply(relay):
+    if relay is not None:
+        os.system('sudo systemctl restart isc-dhcpv6-relay.service')
+    else:
+        # DHCPv6 relay support is removed in the commit
+        os.system('sudo systemctl stop isc-dhcpv6-relay.service')
+        os.unlink(config_file)
+
+    return None
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        sys.exit(1)