T1016: fix IPv4/IPv6 dhcp relay restart command

Current implementation referred to a no longer existing Perl script to
restart the IPv4 and IPv6 instance of dhcrelay.

> restart dhcp relay-agent
> restart dhcpv6 relay-agent

(cherry picked from commit f9007c5f5e6e7957ab1c955c10b3842dca7b253d)

2 files changed, 55 insertions, 2 deletions

diff --git a/op-mode-definitions/dhcp.xml b/op-mode-definitions/dhcp.xml
index eb57f8f1f..a7d09304e 100644
--- a/op-mode-definitions/dhcp.xml
+++ b/op-mode-definitions/dhcp.xml
@@ -83,7 +83,7 @@
             <properties>
               <help>Restart the DHCP server process</help>
             </properties>
-            <command>sudo /opt/vyatta/sbin/dhcrelay-starter.pl --op-mode --init='/opt/vyatta/sbin/dhcrelay.init'</command>
+            <command>sudo ${vyos_op_scripts_dir}/restart_dhcp_relay.py --ipv4</command>
           </node>
         </children>
       </node>
@@ -102,7 +102,7 @@
             <properties>
               <help>Restart the DHCP server process</help>
             </properties>
-            <command>sudo /opt/vyatta/sbin/dhcv6relay-starter.pl --op_mode --config_action ACTIVE</command>
+            <command>sudo ${vyos_op_scripts_dir}/restart_dhcp_relay.py --ipv6</command>
           </node>
         </children>
       </node>
diff --git a/src/op_mode/restart_dhcp_relay.py b/src/op_mode/restart_dhcp_relay.py
new file mode 100755
index 000000000..ab02d1eb3
--- /dev/null
+++ b/src/op_mode/restart_dhcp_relay.py
@@ -0,0 +1,53 @@
+#!/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/>.
+
+# File: restart_dhcp_relay.py
+# Purpose:
+#    Restart IPv4 and IPv6 DHCP relay instances of dhcrelay service
+
+import sys
+import argparse
+import os
+
+import vyos.config
+
+parser = argparse.ArgumentParser()
+parser.add_argument("--ipv4", action="store_true", help="Restart IPv4 DHCP relay")
+parser.add_argument("--ipv6", action="store_true", help="Restart IPv6 DHCP relay")
+
+if __name__ == '__main__':
+    args = parser.parse_args()
+    c = vyos.config.Config()
+
+    if args.ipv4:
+        # Do nothing if service is not configured
+        if not c.exists_effective('service dhcp-relay'):
+            print("DHCP relay service not configured")
+        else:
+            os.system('sudo systemctl restart isc-dhcp-relay.service')
+
+        sys.exit(0)
+    elif args.ipv6:
+        # Do nothing if service is not configured
+        if not c.exists_effective('service dhcpv6-relay'):
+            print("DHCPv6 relay service not configured")
+        else:
+            os.system('sudo systemctl restart isc-dhcpv6-relay.service')
+
+        sys.exit(0)
+    else:
+        parser.print_help()
+        sys.exit(1)