[Openvpn-devel,v4,2/8] windows: properly configure TAP driver when no IPv4 is configured

Message ID 20180623183108.18684-1-a@unstable.cc
State Accepted
Headers show
Series
  • Untitled series #262
Related show

Commit Message

Antonio Quartulli June 23, 2018, 6:31 p.m.
From: Antonio Quartulli <antonio@openvpn.net>

This patch ensures that the TAP driver on a windows host is still
configured, even though no IPv4 has been provided.

In this case the TAP driver ioctl will be invoked with a fake
0.0.0.0/0.0.0.0 IPv4 which will simply start the interface and
get it to a working state.

Trac: #208
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
---

Changes from v2:
- rebased on top ov v4 1/8
- extended commit message
- moved did_ifconfig_setup check into test_routes()
- added longer comment into test_routes() to explain check condition

Changes from v3:
- fixed typ0 in condition in test_routes(): from 'c->c1.tuntap' to 'tt'
- tested on Win10 against ipv6-only and ipv6+ipv4 server (on same LAN)


 src/openvpn/route.c |  6 +++++-
 src/openvpn/tun.c   | 24 +++++++++++++++++-------
 2 files changed, 22 insertions(+), 8 deletions(-)

Comments

Gert Doering June 23, 2018, 7:02 p.m. | #1
Acked-by: Gert Doering <gert@greenie.muc.de>

Took us a while to get here, but here we are :-) - it compiles!  (And it
actually *works* - tested v4+v6 and v6-only on Win7/64 - with iservice - and 
it does the right thing and logs useful messages)

Your patch has been applied to the master branch.

commit 125e9df9539a0d3aa7894f959ef966464754f1da
Author: Antonio Quartulli
Date:   Sun Jun 24 02:31:08 2018 +0800

     windows: properly configure TAP driver when no IPv4 is configured

     Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
     Acked-by: Gert Doering <gert@greenie.muc.de>
     Message-Id: <20180623183108.18684-1-a@unstable.cc>
     URL: https://www.mail-archive.com/search?l=mid&q=20180623183108.18684-1-a@unstable.cc
     Signed-off-by: Gert Doering <gert@greenie.muc.de>


--
kind regards,

Gert Doering


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Patch

diff --git a/src/openvpn/route.c b/src/openvpn/route.c
index 8990a986..f6962848 100644
--- a/src/openvpn/route.c
+++ b/src/openvpn/route.c
@@ -2642,7 +2642,11 @@  test_routes(const struct route_list *rl, const struct tuntap *tt)
         ret = true;
         adapter_up = true;
 
-        if (rl)
+        /* we do this test only if we have IPv4 routes to install, and if
+         * the tun/tap interface has seen IPv4 ifconfig - because if we
+         * have no IPv4, the check will always fail, failing tun init
+         */
+        if (rl && tt->did_ifconfig_setup)
         {
             struct route_ipv4 *r;
             for (r = rl->routes, len = 0; r; r = r->next, ++len)
diff --git a/src/openvpn/tun.c b/src/openvpn/tun.c
index 2e1c96e6..f9b9c716 100644
--- a/src/openvpn/tun.c
+++ b/src/openvpn/tun.c
@@ -5703,7 +5703,10 @@  open_tun(const char *dev, const char *dev_type, const char *dev_node, struct tun
             msg(M_FATAL, "ERROR: --dev tun also requires --ifconfig");
         }
 
-        if (tt->topology == TOP_SUBNET)
+        /* send 0/0/0 to the TAP driver even if we have no IPv4 configured to
+         * ensure it is somehow initialized.
+         */
+        if (!tt->did_ifconfig_setup || tt->topology == TOP_SUBNET)
         {
             in_addr_t ep[3];
             BOOL status;
@@ -5716,12 +5719,19 @@  open_tun(const char *dev, const char *dev_type, const char *dev_node, struct tun
                                      ep, sizeof(ep),
                                      ep, sizeof(ep), &len, NULL);
 
-            msg(status ? M_INFO : M_FATAL, "Set TAP-Windows TUN subnet mode network/local/netmask = %s/%s/%s [%s]",
-                print_in_addr_t(ep[1], IA_NET_ORDER, &gc),
-                print_in_addr_t(ep[0], IA_NET_ORDER, &gc),
-                print_in_addr_t(ep[2], IA_NET_ORDER, &gc),
-                status ? "SUCCEEDED" : "FAILED");
-
+            if (tt->did_ifconfig_setup)
+            {
+                msg(status ? M_INFO : M_FATAL, "Set TAP-Windows TUN subnet mode network/local/netmask = %s/%s/%s [%s]",
+                    print_in_addr_t(ep[1], IA_NET_ORDER, &gc),
+                    print_in_addr_t(ep[0], IA_NET_ORDER, &gc),
+                    print_in_addr_t(ep[2], IA_NET_ORDER, &gc),
+                    status ? "SUCCEEDED" : "FAILED");
+            }
+            else
+            {
+                msg(status ? M_INFO : M_FATAL, "Set TAP-Windows TUN with fake IPv4 [%s]",
+                    status ? "SUCCEEDED" : "FAILED");
+            }
         }
         else
         {