Switch to OpenVPN 2.4

The behaviour of --link-mtu has changed and we increase the values to
at least have interface MTU greater than IPv6 minimum.
We'll see later to have even greater values in ovpn_link_mtu_dict
(so that the resulting MTU is closer to what we had with 2.3)
or review the whole MTU part completely.

README.rst

@@ -54,7 +54,7 @@ Requirements
 
 - Python 2.6 or 2.7
 - OpenSSL binary and development libraries
-- OpenVPN >= 2.3
+- OpenVPN >= 2.4
 - Babel_ (with Nexedi patches)
 - geoip2: `python library`_ and `country lite database`_ (optional)
 - python-miniupnpc for UPnP support (optional)

debian/control

@@ -8,7 +8,7 @@ X-Python-Version: >= 2.7
 
 Package: re6stnet
 Architecture: all
-Depends: ${misc:Depends}, ${python:Depends}, python-pkg-resources, python-openssl (>= 0.13), openvpn (>= 2.3), babeld (= 1.6.2-nxd1), iproute2 | iproute, openssl
+Depends: ${misc:Depends}, ${python:Depends}, python-pkg-resources, python-openssl (>= 0.13), openvpn (>= 2.4), babeld (= 1.6.2-nxd1), iproute2 | iproute, openssl
 Recommends: ${python:Recommends}, logrotate
 Suggests: ${python:Suggests}, ndisc6
 Conflicts: re6st-node

re6st/plib.py

@@ -23,13 +23,14 @@ def openvpn(iface, encrypt, *args, **kw):
     logging.debug('%r', args)
     return utils.Popen(args, **kw)
 
-ovpn_link_mtu_dict = {'udp': 1432, 'udp6': 1450}
+ovpn_link_mtu_dict = {'udp4': 1500, 'udp6': 1500}
 
 def server(iface, max_clients, dh_path, fd, port, proto, encrypt, *args, **kw):
+    if proto == 'udp':
+        proto = 'udp4'
     client_script = '%s %s' % (ovpn_server, fd)
     try:
         args = ('--link-mtu', str(ovpn_link_mtu_dict[proto]),
-                # mtu-disc ignored for udp6 due to a bug in OpenVPN
                 '--mtu-disc', 'yes') + args
     except KeyError:
         proto += '-server'
@@ -50,6 +51,8 @@ def client(iface, address_list, encrypt, *args, **kw):
     # XXX: We'd like to pass <connection> sections at command-line.
     link_mtu = set()
     for ip, port, proto in address_list:
+        if proto == 'udp':
+            proto = 'udp4'
         remote += '--remote', ip, port, proto
         link_mtu.add(ovpn_link_mtu_dict.get(proto))
     link_mtu, = link_mtu

re6stnet.spec

@@ -12,7 +12,7 @@ BuildArch:  noarch
 Requires:   babeld = 1.6.2-nxd1
 Requires:   iproute
 Requires:   openssl
-Requires:   openvpn >= 2.3
+Requires:   openvpn >= 2.4
 Requires:   python >= 2.7
 Requires:   pyOpenSSL >= 0.13
 Requires:   python-setuptools