@@ -23,11 +23,12 @@ NTLMv1 authentication support for HTTP proxies has been removed.

 ``persist-key`` option has been enabled by default.

     All the keys will be kept in memory across restart.

-Default for ``--topology`` changed to ``subnet``

-    Previous releases used ``net30`` as default. This only affects

-    configs with ``--dev tun`` and only IPv4. Note that this

-    changes the semantics of ``--ifconfig``, so if you have manual

-    settings for that in your config but not set ``--topology``

+Default for ``--topology`` changed to ``subnet`` for ``--mode server``

+    Previous releases always used ``net30`` as default. This only affects

+    configs with ``--mode server`` or ``--server`` (the latter implies the

+    former), and ``--dev tun``, and only if IPv4 is enabled.

+    Note that this changes the semantics of ``--ifconfig``, so if you have

+    manual settings for that in your config but not set ``--topology``

     your config might fail to parse with the new version. Just adding

     ``--topology net30`` to the config should fix the problem.

     By default ``--topology`` is pushed from server to client.

@@ -137,6 +137,32 @@ verify_common_subnet(const char *opt, const in_addr_t a, const in_addr_t b, cons

 }

+/**

+ * Set --topology default depending on --mode

+ */

+void

+helper_setdefault_topology(struct options *o)

+{

+    if (o->topology != TOP_UNDEF)

+    {

+        return;

+    }

+    int dev = dev_type_enum(o->dev, o->dev_type);

+    if (dev != DEV_TYPE_TUN)

+    {

+        return;

+    }

+    if (o->mode == MODE_SERVER)

+    {

+        o->topology = TOP_SUBNET;

+    }

+    else

+    {

+        o->topology = TOP_NET30;

+    }

+}

+

+

 /*

  * Process server, server-bridge, and client helper

  * directives after the parameters themselves have been

@@ -151,7 +177,6 @@ helper_client_server(struct options *o)

      * Get tun/tap/null device type

      */

     const int dev = dev_type_enum(o->dev, o->dev_type);

-    const int topology = o->topology;

     /*

      *

@@ -177,11 +202,11 @@ helper_client_server(struct options *o)

         if (o->server_flags & SF_NOPOOL)

         {

-            msg( M_USAGE, "--server-ipv6 is incompatible with 'nopool' option" );

+            msg(M_USAGE, "--server-ipv6 is incompatible with 'nopool' option");

         }

         if (o->ifconfig_ipv6_pool_defined)

         {

-            msg( M_USAGE, "--server-ipv6 already defines an ifconfig-ipv6-pool, so you can't also specify --ifconfig-pool explicitly");

+            msg(M_USAGE, "--server-ipv6 already defines an ifconfig-ipv6-pool, so you can't also specify --ifconfig-pool explicitly");

         }

         o->mode = MODE_SERVER;

@@ -207,7 +232,7 @@ helper_client_server(struct options *o)

                                                   o->server_netbits_ipv6 < 112 ? 0x1000 : 2);

         o->ifconfig_ipv6_pool_netbits = o->server_netbits_ipv6;

-        push_option( o, "tun-ipv6", M_USAGE );

+        push_option(o, "tun-ipv6", M_USAGE);

     }

     /*

@@ -305,8 +330,10 @@ helper_client_server(struct options *o)

             o->mode = MODE_SERVER;

             o->tls_server = true;

+            /* Need to know topology now */

+            helper_setdefault_topology(o);

-            if (topology == TOP_NET30 || topology == TOP_P2P)

+            if (o->topology == TOP_NET30 || o->topology == TOP_P2P)

             {

                 o->ifconfig_local = print_in_addr_t(o->server_network + 1, 0, &o->gc);

                 o->ifconfig_remote_netmask = print_in_addr_t(o->server_network + 2, 0, &o->gc);

@@ -324,12 +351,12 @@ helper_client_server(struct options *o)

                 {

                     push_option(o, print_opt_route(o->server_network, o->server_netmask, &o->gc), M_USAGE);

                 }

-                else if (topology == TOP_NET30)

+                else if (o->topology == TOP_NET30)

                 {

                     push_option(o, print_opt_route(o->server_network + 1, 0, &o->gc), M_USAGE);

                 }

             }

-            else if (topology == TOP_SUBNET)

+            else if (o->topology == TOP_SUBNET)

             {

                 o->ifconfig_local = print_in_addr_t(o->server_network + 1, 0, &o->gc);

                 o->ifconfig_remote_netmask = print_in_addr_t(o->server_netmask, 0, &o->gc);

@@ -354,9 +381,9 @@ helper_client_server(struct options *o)

                 ASSERT(0);

             }

-            push_option(o, print_opt_topology(topology, &o->gc), M_USAGE);

+            push_option(o, print_opt_topology(o->topology, &o->gc), M_USAGE);

-            if (topology == TOP_NET30 && !(o->server_flags & SF_NOPOOL))

+            if (o->topology == TOP_NET30 && !(o->server_flags & SF_NOPOOL))

             {

                 msg(M_WARN, "WARNING: --topology net30 support for server "

                     "configs with IPv4 pools will be removed in a future "

@@ -394,7 +421,7 @@ helper_client_server(struct options *o)

         }

         /* set push-ifconfig-constraint directive */

-        if ((dev == DEV_TYPE_TAP || topology == TOP_SUBNET))

+        if ((dev == DEV_TYPE_TAP || o->topology == TOP_SUBNET))

         {

             o->push_ifconfig_constraint_defined = true;

             o->push_ifconfig_constraint_network = o->server_network;

@@ -30,6 +30,8 @@

 #include "options.h"

+void helper_setdefault_topology(struct options *o);

+

 void helper_keepalive(struct options *o);

 void helper_client_server(struct options *o);

@@ -796,7 +796,7 @@ init_options(struct options *o, const bool init_gc)

         o->gc_owned = true;

     }

     o->mode = MODE_POINT_TO_POINT;

-    o->topology = TOP_SUBNET;

+    o->topology = TOP_UNDEF;

     o->ce.proto = PROTO_UDP;

     o->ce.af = AF_UNSPEC;

     o->ce.bind_ipv6_only = false;

@@ -3478,6 +3478,7 @@ options_postprocess_verify(const struct options *o)

     }

 }

+

 /**

  * Checks for availibility of Chacha20-Poly1305 and sets

  * the ncp_cipher to either AES-256-GCM:AES-128-GCM or

@@ -3680,6 +3681,8 @@ options_postprocess_mutate(struct options *o, struct env_set *es)

      * sequences of options.

      */

     helper_client_server(o);

+    /* must be called after helpers that might set --mode */

+    helper_setdefault_topology(o);

     helper_keepalive(o);

     helper_tcp_nodelay(o);