openvpn: T3051: fix creation of ifconfig-pool for client communication

2 files changed, 25 insertions, 13 deletions

diff --git a/data/templates/openvpn/server.conf.tmpl b/data/templates/openvpn/server.conf.tmpl
index 66da9c794..e8f7c3ab8 100644
--- a/data/templates/openvpn/server.conf.tmpl
+++ b/data/templates/openvpn/server.conf.tmpl
@@ -60,24 +60,24 @@ mode server
 tls-server
 {%   if server is defined and server is not none %}
 {%     if server.subnet is defined and server.subnet is not none %}
+{%     if server.topology is defined and server.topology == 'point-to-point' %}
+topology p2p
+{%     elif server.topology is defined and server.topology is not none %}
+topology {{ server.topology }}
+{%     endif %}
 {%       for subnet in server.subnet if subnet | ipv4 %}
 server {{ subnet | address_from_cidr }} {{ subnet | netmask_from_cidr }} nopool
 {# OpenVPN assigns the first IP address to its local interface so the pool used #}
 {# in net30 topology - where each client receives a /30 must start from the second subnet #}
 {%     if server.topology is defined and server.topology == 'net30' %}
-ifconfig-pool {{ subnet | inc_ip('4') }} {{ subnet | last_host_address }} {{ subnet | netmask_from_cidr if device_type == 'tap' else '' }}
+ifconfig-pool {{ subnet | inc_ip('4') }} {{ subnet | last_host_address | dec_ip('1') }} {{ subnet | netmask_from_cidr if device_type == 'tap' else '' }}
 {%     else %}
 {# OpenVPN assigns the first IP address to its local interface so the pool must #}
 {# start from the second address and end on the last address #}
-ifconfig-pool {{ subnet | first_host_address | inc_ip('1') }} {{ subnet | last_host_address }} {{ subnet | netmask_from_cidr if device_type == 'tap' else '' }}
+ifconfig-pool {{ subnet | first_host_address | inc_ip('1') }} {{ subnet | last_host_address | dec_ip('1') }} {{ subnet | netmask_from_cidr if device_type == 'tun' else '' }}
 {%     endif %}
 {%       endfor %}
 {%     endif %}
-{%     if server.topology is defined and server.topology == 'point-to-point' %}
-topology p2p
-{%     elif server.topology is defined and server.topology is not none %}
-topology {{ server.topology }}
-{%     endif %}
 {%     if server.client_ip_pool is defined and server.client_ip_pool is not none and server.client_ip_pool.disable is not defined %}
 ifconfig-pool {{ server.client_ip_pool.start }} {{ server.client_ip_pool.stop }}{{ server.client_ip_pool.subnet_mask if server.client_ip_pool.subnet_mask is defined and server.client_ip_pool.subnet_mask is not none }}
 {%     endif %}
diff --git a/python/vyos/template.py b/python/vyos/template.py
index 389f6927f..53e1dc1b5 100644
--- a/python/vyos/template.py
+++ b/python/vyos/template.py
@@ -190,11 +190,23 @@ def vyos_last_host_address(text):
     return str(IPv6Network(addr).broadcast_address)
 
 @register_filter('inc_ip')
-def vyos_inc_ip(text, increment):
-    """ Return first usable IP address from given prefix.
-    Example:
-      - 10.0.0.0/24 -> 10.0.0.1
-      - 2001:db8::/64 -> 2001:db8::1
+def vyos_inc_ip(address, increment):
+    """ Increment given IP address by 'increment'
+
+    Example (inc by 2):
+      - 10.0.0.0/24 -> 10.0.0.2
+      - 2001:db8::/64 -> 2001:db8::2
+    """
+    from ipaddress import ip_interface
+    return str(ip_interface(address).ip + int(increment))
+
+@register_filter('dec_ip')
+def vyos_dec_ip(address, decrement):
+    """ Decrement given IP address by 'decrement'
+
+    Example (inc by 2):
+      - 10.0.0.0/24 -> 10.0.0.2
+      - 2001:db8::/64 -> 2001:db8::2
     """
     from ipaddress import ip_interface
-    return str(ip_interface(text).ip + int(increment))
+    return str(ip_interface(address).ip - int(decrement))