attempt to add IPv6 route even when no IPv6 address was configured

Even if no IPv6 address is configured, OpenVPN still supports
transporting IPv6 segments, therefore adding an IPv6 route
should always be allowed.

However, the route might fail to be installed or may just not work
as expected, therefore, a proper warning should be printed to inform
the user of the possible pitfall.

Always allow adding an IPv6 route and print a WARNING when
no IPv6 address is configured for the interface.

Trac: #832
Signed-off-by: Antonio Quartulli <a@unstable.cc>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20170131112131.13570-1-a@unstable.cc>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg13994.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

diff --git a/src/openvpn/route.c b/src/openvpn/route.c
index 223cb5f4c3777ba50f449da495fa1fa0d6736c7e..0145db3c6f97c74a3c06225feb18d332441c4e59 100644 (file)
--- a/src/openvpn/route.c
+++ b/src/openvpn/route.c
@@ -1196,6 +1196,15 @@ add_routes(struct route_list *rl, struct route_ipv6_list *rl6, const struct tunt
     if (rl6 && !(rl6->iflags & RL_ROUTES_ADDED) )
     {
         struct route_ipv6 *r;
+
+        if (!tt->did_ifconfig_ipv6_setup)
+        {
+            msg(M_INFO, "WARNING: OpenVPN was configured to add an IPv6 "
+                "route over %s. However, no IPv6 has been configured for "
+                "this interface, therefore the route installation may "
+                "fail or may not work as expected.", tt->actual_name);
+        }
+
         for (r = rl6->routes_ipv6; r; r = r->next)
         {
             if (flags & ROUTE_DELETE_FIRST)
@@ -1882,14 +1891,6 @@ add_route_ipv6(struct route_ipv6 *r6, const struct tuntap *tt, unsigned int flag
     }
 #endif
 
-    if (!tt->did_ifconfig_ipv6_setup)
-    {
-        msg( M_INFO, "add_route_ipv6(): not adding %s/%d: "
-             "no IPv6 address been configured on interface %s",
-             network, r6->netbits, device);
-        return;
-    }
-
     msg( M_INFO, "add_route_ipv6(%s/%d -> %s metric %d) dev %s",
          network, r6->netbits, gateway, r6->metric, device );