Move to common backend_driver type in struct tuntap

With the introduction of utun on macOS and DCO on Linux, FreeBSD and Windows, a lot of platforms have now more than one driver/backend for the tun interface but each one uses a different mechanism. Unify these approach with using a common enum that defines the driver_type. Change-Id: I8c0e9f32b235cb262ca2be6aac8d520e49b30d74 Signed-off-by: Arne Schwabe <[email protected]> Acked-by: Gert Doering <[email protected]> Message-Id: <[email protected]> URL: https://www.mail-archive.com/[email protected]/msg29352.html Signed-off-by: Gert Doering <[email protected]>
OpenVPN · Sep 22, 2024 · d849073 · d849073
1 parent b322690
commit d849073
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Showing 8 changed files with 110 additions and 98 deletions.
diff --git a/src/openvpn/dco.c b/src/openvpn/dco.c
@@ -328,7 +328,7 @@ dco_check_startup_option(int msglevel, const struct options *o)
         || (o->windows_driver == WINDOWS_DRIVER_TAP_WINDOWS6))
     {
         msg(msglevel, "--windows-driver is set to '%s'. Disabling Data Channel Offload",
-            print_windows_driver(o->windows_driver));
+            print_tun_backend_driver(o->windows_driver));
         return false;
     }
 

diff --git a/src/openvpn/dco_win.c b/src/openvpn/dco_win.c
@@ -44,7 +44,7 @@ const IN_ADDR in4addr_any = { 0 };
 struct tuntap
 create_dco_handle(const char *devname, struct gc_arena *gc)
 {
-    struct tuntap tt = { .windows_driver = WINDOWS_DRIVER_DCO };
+    struct tuntap tt = { .backend_driver = DRIVER_DCO };
     const char *device_guid;
 
     tun_open_device(&tt, devname, &device_guid, gc);

diff --git a/src/openvpn/forward.c b/src/openvpn/forward.c
@@ -1299,7 +1299,7 @@ read_incoming_tun(struct context *c)
     c->c2.buf = c->c2.buffers->read_tun_buf;
 
 #ifdef _WIN32
-    if (c->c1.tuntap->windows_driver == WINDOWS_DRIVER_WINTUN)
+    if (c->c1.tuntap->backend_driver == WINDOWS_DRIVER_WINTUN)
     {
         read_wintun(c->c1.tuntap, &c->c2.buf);
         if (c->c2.buf.len == -1)

diff --git a/src/openvpn/init.c b/src/openvpn/init.c
@@ -1126,7 +1126,7 @@ do_persist_tuntap(struct options *options, openvpn_net_ctx_t *ctx)
             msg(M_WARN, "Note: --mktun does not support DCO. Creating TUN interface.");
         }
 
-        options->tuntap_options.disable_dco = true;
+        options->disable_dco = true;
     }
 #endif
 
@@ -1759,7 +1759,16 @@ do_init_tun(struct context *c)
                             c->c1.tuntap);
 
 #ifdef _WIN32
-    c->c1.tuntap->windows_driver = c->options.windows_driver;
+    c->c1.tuntap->backend_driver = c->options.windows_driver;
+#else
+    if (dco_enabled(&c->options))
+    {
+        c->c1.tuntap->backend_driver = DRIVER_DCO;
+    }
+    else
+    {
+        c->c1.tuntap->backend_driver = DRIVER_GENERIC_TUNTAP;
+    }
 #endif
 
     init_tun_post(c->c1.tuntap,

diff --git a/src/openvpn/options.c b/src/openvpn/options.c
@@ -905,7 +905,7 @@ init_options(struct options *o, const bool init_gc)
     o->allow_recursive_routing = false;
 
 #ifndef ENABLE_DCO
-    o->tuntap_options.disable_dco = true;
+    o->disable_dco = true;
 #endif /* ENABLE_DCO */
 }
 
@@ -1829,7 +1829,7 @@ show_settings(const struct options *o)
     SHOW_STR(dev_type);
     SHOW_STR(dev_node);
 #if defined(ENABLE_DCO)
-    SHOW_BOOL(tuntap_options.disable_dco);
+    SHOW_BOOL(disable_dco);
 #endif
     SHOW_STR(lladdr);
     SHOW_INT(topology);
@@ -2489,7 +2489,7 @@ options_postprocess_verify_ce(const struct options *options,
         if (options->windows_driver != WINDOWS_DRIVER_TAP_WINDOWS6)
         {
             msg(M_USAGE, "%s, which is not supported by the selected %s driver",
-                prefix, print_windows_driver(options->windows_driver));
+                prefix, print_tun_backend_driver(options->windows_driver));
         }
         else if (options->tuntap_options.ip_win32_type != IPW32_SET_DHCP_MASQ
                  && options->tuntap_options.ip_win32_type != IPW32_SET_ADAPTIVE)
@@ -3403,7 +3403,7 @@ options_postprocess_mutate_invariant(struct options *options)
 
     /* when using wintun/ovpn-dco, kernel doesn't send DHCP requests, so don't use it */
     if ((options->windows_driver == WINDOWS_DRIVER_WINTUN
-         || options->windows_driver == WINDOWS_DRIVER_DCO)
+         || options->windows_driver == DRIVER_DCO)
         && (options->tuntap_options.ip_win32_type == IPW32_SET_DHCP_MASQ
             || options->tuntap_options.ip_win32_type == IPW32_SET_ADAPTIVE))
     {
@@ -3777,8 +3777,8 @@ options_postprocess_mutate(struct options *o, struct env_set *es)
     if (dco_enabled(o))
     {
         /* check if any option should force disabling DCO */
-        o->tuntap_options.disable_dco = !dco_check_option(D_DCO, o)
-                                        || !dco_check_startup_option(D_DCO, o);
+        o->disable_dco = !dco_check_option(D_DCO, o)
+                         || !dco_check_startup_option(D_DCO, o);
     }
 #ifdef USE_COMP
     if (dco_enabled(o))
@@ -3790,11 +3790,11 @@ options_postprocess_mutate(struct options *o, struct env_set *es)
 #ifdef _WIN32
     if (dco_enabled(o))
     {
-        o->windows_driver = WINDOWS_DRIVER_DCO;
+        o->windows_driver = DRIVER_DCO;
     }
     else
     {
-        if (o->windows_driver == WINDOWS_DRIVER_DCO)
+        if (o->windows_driver == DRIVER_DCO)
         {
             msg(M_WARN, "Option --windows-driver ovpn-dco is ignored because Data Channel Offload is disabled");
             o->windows_driver = WINDOWS_DRIVER_TAP_WINDOWS6;
@@ -4699,9 +4699,9 @@ options_string_extract_option(const char *options_string, const char *opt_name,
  *
  * @param str       value of --windows-driver option
  * @param msglevel  msglevel to report parsing error
- * @return enum windows_driver_type  driver type, WINDOWS_DRIVER_UNSPECIFIED on unknown --windows-driver value
+ * @return enum tun_driver_type  driver type, WINDOWS_DRIVER_UNSPECIFIED on unknown --windows-driver value
  */
-static enum windows_driver_type
+static enum tun_driver_type
 parse_windows_driver(const char *str, const int msglevel)
 {
     if (streq(str, "tap-windows6"))
@@ -4715,7 +4715,7 @@ parse_windows_driver(const char *str, const int msglevel)
 
     else if (streq(str, "ovpn-dco"))
     {
-        return WINDOWS_DRIVER_DCO;
+        return DRIVER_DCO;
     }
     else
     {
@@ -6053,7 +6053,7 @@ add_option(struct options *options,
 #endif
     else if (streq(p[0], "disable-dco"))
     {
-        options->tuntap_options.disable_dco = true;
+        options->disable_dco = true;
     }
     else if (streq(p[0], "dev-node") && p[1] && !p[2])
     {

diff --git a/src/openvpn/options.h b/src/openvpn/options.h
@@ -354,6 +354,9 @@ struct options
     const char *ip_remote_hint;
 
     struct tuntap_options tuntap_options;
+    /* DCO is disabled and should not be used as backend driver for the
+     * tun/tap device */
+    bool disable_dco;
 
     /* Misc parms */
     const char *username;
@@ -676,7 +679,7 @@ struct options
     bool show_net_up;
     int route_method;
     bool block_outside_dns;
-    enum windows_driver_type windows_driver;
+    enum tun_driver_type windows_driver;
 #endif
 
     bool use_peer_id;
@@ -907,7 +910,7 @@ static inline bool
 dco_enabled(const struct options *o)
 {
 #ifdef ENABLE_DCO
-    return !o->tuntap_options.disable_dco;
+    return !o->disable_dco;
 #else
     return false;
 #endif /* ENABLE_DCO */