@@ -1847,8 +1847,11 @@ static void

 do_close_tun_simple(struct context *c)

 {

     msg(D_CLOSE, "Closing TUN/TAP interface");

-    close_tun(c->c1.tuntap);

-    c->c1.tuntap = NULL;

+    if (c->c1.tuntap)

+    {

+        close_tun(c->c1.tuntap);

+        c->c1.tuntap = NULL;

+    }

     c->c1.tuntap_owned = false;

 #if P2MP

     CLEAR(c->c1.pulled_options_digest_save);

@@ -1900,11 +1900,10 @@ open_tun(const char *dev, const char *dev_type, const char *dev_node, struct tun

 void

 close_tun(struct tuntap *tt)

 {

-    if (tt)

-    {

-        close_tun_generic(tt);

-        free(tt);

-    }

+    ASSERT(tt);

+

+    close_tun_generic(tt);

+    free(tt);

 }

 int

@@ -2103,77 +2102,76 @@ tuncfg(const char *dev, const char *dev_type, const char *dev_node, int persist_

 void

 close_tun(struct tuntap *tt)

 {

-    if (tt)

+    ASSERT(tt);

+

+    if (tt->type != DEV_TYPE_NULL && tt->did_ifconfig)

     {

-        if (tt->type != DEV_TYPE_NULL && tt->did_ifconfig)

-        {

-            struct argv argv = argv_new();

-            struct gc_arena gc = gc_new();

+        struct argv argv = argv_new();

+        struct gc_arena gc = gc_new();

 #ifdef ENABLE_IPROUTE

-            if (is_tun_p2p(tt))

-            {

-                argv_printf(&argv,

-                            "%s addr del dev %s local %s peer %s",

-                            iproute_path,

-                            tt->actual_name,

-                            print_in_addr_t(tt->local, 0, &gc),

-                            print_in_addr_t(tt->remote_netmask, 0, &gc)

-                            );

-            }

-            else

-            {

-                argv_printf(&argv,

-                            "%s addr del dev %s %s/%d",

-                            iproute_path,

-                            tt->actual_name,

-                            print_in_addr_t(tt->local, 0, &gc),

-                            netmask_to_netbits2(tt->remote_netmask)

-                            );

-            }

-#else  /* ifdef ENABLE_IPROUTE */

+        if (is_tun_p2p(tt))

+        {

             argv_printf(&argv,

-                        "%s %s 0.0.0.0",

-                        IFCONFIG_PATH,

-                        tt->actual_name

-                        );

+                        "%s addr del dev %s local %s peer %s",

+                        iproute_path,

+                        tt->actual_name,

+                        print_in_addr_t(tt->local, 0, &gc),

+                        print_in_addr_t(tt->remote_netmask, 0, &gc)

+                       );

+        }

+        else

+        {

+            argv_printf(&argv,

+                        "%s addr del dev %s %s/%d",

+                        iproute_path,

+                        tt->actual_name,

+                        print_in_addr_t(tt->local, 0, &gc),

+                        netmask_to_netbits2(tt->remote_netmask)

+                       );

+        }

+#else  /* ifdef ENABLE_IPROUTE */

+        argv_printf(&argv,

+                    "%s %s 0.0.0.0",

+                    IFCONFIG_PATH,

+                    tt->actual_name

+                   );

 #endif /* ifdef ENABLE_IPROUTE */

-            argv_msg(M_INFO, &argv);

-            openvpn_execve_check(&argv, NULL, 0, "Linux ip addr del failed");

+        argv_msg(M_INFO, &argv);

+        openvpn_execve_check(&argv, NULL, 0, "Linux ip addr del failed");

-            if (tt->did_ifconfig_ipv6_setup)

-            {

-                const char *ifconfig_ipv6_local = print_in6_addr(tt->local_ipv6, 0, &gc);

+        if (tt->did_ifconfig_ipv6_setup)

+        {

+            const char *ifconfig_ipv6_local = print_in6_addr(tt->local_ipv6, 0, &gc);

 #ifdef ENABLE_IPROUTE

-                argv_printf(&argv, "%s -6 addr del %s/%d dev %s",

-                            iproute_path,

-                            ifconfig_ipv6_local,

-                            tt->netbits_ipv6,

-                            tt->actual_name

-                            );

-                argv_msg(M_INFO, &argv);

-                openvpn_execve_check(&argv, NULL, 0, "Linux ip -6 addr del failed");

+            argv_printf(&argv, "%s -6 addr del %s/%d dev %s",

+                        iproute_path,

+                        ifconfig_ipv6_local,

+                        tt->netbits_ipv6,

+                        tt->actual_name

+                       );

+            argv_msg(M_INFO, &argv);

+            openvpn_execve_check(&argv, NULL, 0, "Linux ip -6 addr del failed");

 #else  /* ifdef ENABLE_IPROUTE */

-                argv_printf(&argv,

-                            "%s %s del %s/%d",

-                            IFCONFIG_PATH,

-                            tt->actual_name,

-                            ifconfig_ipv6_local,

-                            tt->netbits_ipv6

-                            );

-                argv_msg(M_INFO, &argv);

-                openvpn_execve_check(&argv, NULL, 0, "Linux ifconfig inet6 del failed");

+            argv_printf(&argv,

+                        "%s %s del %s/%d",

+                        IFCONFIG_PATH,

+                        tt->actual_name,

+                        ifconfig_ipv6_local,

+                        tt->netbits_ipv6

+                       );

+            argv_msg(M_INFO, &argv);

+            openvpn_execve_check(&argv, NULL, 0, "Linux ifconfig inet6 del failed");

 #endif

-            }

-

-            argv_reset(&argv);

-            gc_free(&gc);

         }

-        close_tun_generic(tt);

-        free(tt);

+

+        argv_reset(&argv);

+        gc_free(&gc);

     }

+    close_tun_generic(tt);

+    free(tt);

 }

 int

@@ -2431,57 +2429,54 @@ open_tun(const char *dev, const char *dev_type, const char *dev_node, struct tun

 static void

 solaris_close_tun(struct tuntap *tt)

 {

-    if (tt)

+    /* IPv6 interfaces need to be 'manually' de-configured */

+    if (tt->did_ifconfig_ipv6_setup)

     {

-        /* IPv6 interfaces need to be 'manually' de-configured */

-        if (tt->did_ifconfig_ipv6_setup)

+        struct argv argv = argv_new();

+        argv_printf( &argv, "%s %s inet6 unplumb",

+                     IFCONFIG_PATH, tt->actual_name );

+        argv_msg(M_INFO, &argv);

+        openvpn_execve_check(&argv, NULL, 0, "Solaris ifconfig inet6 unplumb failed");

+        argv_reset(&argv);

+    }

+

+    if (tt->ip_fd >= 0)

+    {

+        struct lifreq ifr;

+        CLEAR(ifr);

+        strncpynt(ifr.lifr_name, tt->actual_name, sizeof(ifr.lifr_name));

+

+        if (ioctl(tt->ip_fd, SIOCGLIFFLAGS, &ifr) < 0)

         {

-            struct argv argv = argv_new();

-            argv_printf( &argv, "%s %s inet6 unplumb",

-                         IFCONFIG_PATH, tt->actual_name );

-            argv_msg(M_INFO, &argv);

-            openvpn_execve_check(&argv, NULL, 0, "Solaris ifconfig inet6 unplumb failed");

-            argv_reset(&argv);

+            msg(M_WARN | M_ERRNO, "Can't get iface flags");

         }

-        if (tt->ip_fd >= 0)

+        if (ioctl(tt->ip_fd, SIOCGLIFMUXID, &ifr) < 0)

         {

-            struct lifreq ifr;

-            CLEAR(ifr);

-            strncpynt(ifr.lifr_name, tt->actual_name, sizeof(ifr.lifr_name));

-

-            if (ioctl(tt->ip_fd, SIOCGLIFFLAGS, &ifr) < 0)

-            {

-                msg(M_WARN | M_ERRNO, "Can't get iface flags");

-            }

-

-            if (ioctl(tt->ip_fd, SIOCGLIFMUXID, &ifr) < 0)

-            {

-                msg(M_WARN | M_ERRNO, "Can't get multiplexor id");

-            }

-

-            if (tt->type == DEV_TYPE_TAP)

-            {

-                if (ioctl(tt->ip_fd, I_PUNLINK, ifr.lifr_arp_muxid) < 0)

-                {

-                    msg(M_WARN | M_ERRNO, "Can't unlink interface(arp)");

-                }

-            }

+            msg(M_WARN | M_ERRNO, "Can't get multiplexor id");

+        }

-            if (ioctl(tt->ip_fd, I_PUNLINK, ifr.lifr_ip_muxid) < 0)

+        if (tt->type == DEV_TYPE_TAP)

+        {

+            if (ioctl(tt->ip_fd, I_PUNLINK, ifr.lifr_arp_muxid) < 0)

             {

-                msg(M_WARN | M_ERRNO, "Can't unlink interface(ip)");

+                msg(M_WARN | M_ERRNO, "Can't unlink interface(arp)");

             }

-

-            close(tt->ip_fd);

-            tt->ip_fd = -1;

         }

-        if (tt->fd >= 0)

+        if (ioctl(tt->ip_fd, I_PUNLINK, ifr.lifr_ip_muxid) < 0)

         {

-            close(tt->fd);

-            tt->fd = -1;

+            msg(M_WARN | M_ERRNO, "Can't unlink interface(ip)");

         }

+

+        close(tt->ip_fd);

+        tt->ip_fd = -1;

+    }

+

+    if (tt->fd >= 0)

+    {

+        close(tt->fd);

+        tt->fd = -1;

     }

 }

@@ -2491,18 +2486,17 @@ solaris_close_tun(struct tuntap *tt)

 void

 close_tun(struct tuntap *tt)

 {

-    if (tt)

-    {

-        solaris_close_tun(tt);

+    ASSERT(tt);

-        if (tt->actual_name)

-        {

-            free(tt->actual_name);

-        }

+    solaris_close_tun(tt);

-        clear_tuntap(tt);

-        free(tt);

+    if (tt->actual_name)

+    {

+        free(tt->actual_name);

     }

+

+    clear_tuntap(tt);

+    free(tt);

 }

 static void

@@ -2591,31 +2585,32 @@ open_tun(const char *dev, const char *dev_type, const char *dev_node, struct tun

 void

 close_tun(struct tuntap *tt)

 {

+    ASSERT(tt);

+

     /* only *TAP* devices need destroying, tun devices auto-self-destruct

      */

-    if (tt && (tt->type == DEV_TYPE_TUN || tt->persistent_if ) )

+    if (tt->type == DEV_TYPE_TUN || tt->persistent_if)

     {

         close_tun_generic(tt);

         free(tt);

+        return;

     }

-    else if (tt)

-    {

-        struct argv argv = argv_new();

-        /* setup command, close tun dev (clears tt->actual_name!), run command

-         */

+    struct argv argv = argv_new();

-        argv_printf(&argv, "%s %s destroy",

-                    IFCONFIG_PATH, tt->actual_name);

+    /* setup command, close tun dev (clears tt->actual_name!), run command

+    */

-        close_tun_generic(tt);

+    argv_printf(&argv, "%s %s destroy",

+                IFCONFIG_PATH, tt->actual_name);

-        argv_msg(M_INFO, &argv);

-        openvpn_execve_check(&argv, NULL, 0, "OpenBSD 'destroy tun interface' failed (non-critical)");

+    close_tun_generic(tt);

-        free(tt);

-        argv_reset(&argv);

-    }

+    argv_msg(M_INFO, &argv);

+    openvpn_execve_check(&argv, NULL, 0, "OpenBSD 'destroy tun interface' failed (non-critical)");

+

+    free(tt);

+    argv_reset(&argv);

 }

 int

@@ -2676,31 +2671,32 @@ open_tun(const char *dev, const char *dev_type, const char *dev_node, struct tun

 void

 close_tun(struct tuntap *tt)

 {

+    ASSERT(tt);

+

     /* only tun devices need destroying, tap devices auto-self-destruct

      */

-    if (tt && ( tt->type != DEV_TYPE_TUN || tt->persistent_if ) )

+    if (tt->type != DEV_TYPE_TUN || tt->persistent_if)

     {

         close_tun_generic(tt);

         free(tt);

+        return;

     }

-    else if (tt)

-    {

-        struct argv argv = argv_new();

-        /* setup command, close tun dev (clears tt->actual_name!), run command

-         */

+    struct argv argv = argv_new();

-        argv_printf(&argv, "%s %s destroy",

-                    IFCONFIG_PATH, tt->actual_name);

+    /* setup command, close tun dev (clears tt->actual_name!), run command

+    */

-        close_tun_generic(tt);

+    argv_printf(&argv, "%s %s destroy",

+                IFCONFIG_PATH, tt->actual_name);

-        argv_msg(M_INFO, &argv);

-        openvpn_execve_check(&argv, NULL, 0, "NetBSD 'destroy tun interface' failed (non-critical)");

+    close_tun_generic(tt);

-        free(tt);

-        argv_reset(&argv);

-    }

+    argv_msg(M_INFO, &argv);

+    openvpn_execve_check(&argv, NULL, 0, "NetBSD 'destroy tun interface' failed (non-critical)");

+

+    free(tt);

+    argv_reset(&argv);

 }

 static inline int

@@ -2816,29 +2812,32 @@ open_tun(const char *dev, const char *dev_type, const char *dev_node, struct tun

 void

 close_tun(struct tuntap *tt)

 {

-    if (tt && tt->persistent_if)        /* keep pre-existing if around */

+    ASSERT(tt);

+

+    if (tt->persistent_if)        /* keep pre-existing if around */

     {

         close_tun_generic(tt);

         free(tt);

+        return;

     }

-    else if (tt)                        /* close and destroy */

-    {

-        struct argv argv = argv_new();

-        /* setup command, close tun dev (clears tt->actual_name!), run command

-         */

+    /* close and destroy */

+    struct argv argv = argv_new();

-        argv_printf(&argv, "%s %s destroy",

-                    IFCONFIG_PATH, tt->actual_name);

+    /* setup command, close tun dev (clears tt->actual_name!), run command

+    */

-        close_tun_generic(tt);

+    argv_printf(&argv, "%s %s destroy",

+                IFCONFIG_PATH, tt->actual_name);

-        argv_msg(M_INFO, &argv);

-        openvpn_execve_check(&argv, NULL, 0, "FreeBSD 'destroy tun interface' failed (non-critical)");

+    close_tun_generic(tt);

-        free(tt);

-        argv_reset(&argv);

-    }

+    argv_msg(M_INFO, &argv);

+    openvpn_execve_check(&argv, NULL, 0,

+                         "FreeBSD 'destroy tun interface' failed (non-critical)");

+

+    free(tt);

+    argv_reset(&argv);

 }

 int

@@ -2929,11 +2928,10 @@ open_tun(const char *dev, const char *dev_type, const char *dev_node, struct tun

 void

 close_tun(struct tuntap *tt)

 {

-    if (tt)

-    {

-        close_tun_generic(tt);

-        free(tt);

-    }

+    ASSERT(tt);

+

+    close_tun_generic(tt);

+    free(tt);

 }

 int

@@ -3186,27 +3184,26 @@ open_tun(const char *dev, const char *dev_type, const char *dev_node, struct tun

 void

 close_tun(struct tuntap *tt)

 {

-    if (tt)

-    {

-        struct gc_arena gc = gc_new();

-        struct argv argv = argv_new();

+    ASSERT(tt);

-        if (tt->did_ifconfig_ipv6_setup)

-        {

-            const char *ifconfig_ipv6_local =

-                print_in6_addr(tt->local_ipv6, 0, &gc);

+    struct gc_arena gc = gc_new();

+    struct argv argv = argv_new();

-            argv_printf(&argv, "%s delete -inet6 %s",

-                        ROUTE_PATH, ifconfig_ipv6_local );

-            argv_msg(M_INFO, &argv);

-            openvpn_execve_check(&argv, NULL, 0, "MacOS X 'remove inet6 route' failed (non-critical)");

-        }

+    if (tt->did_ifconfig_ipv6_setup)

+    {

+        const char *ifconfig_ipv6_local =

+            print_in6_addr(tt->local_ipv6, 0, &gc);

-        close_tun_generic(tt);

-        free(tt);

-        argv_reset(&argv);

-        gc_free(&gc);

+        argv_printf(&argv, "%s delete -inet6 %s",

+                    ROUTE_PATH, ifconfig_ipv6_local );

+        argv_msg(M_INFO, &argv);

+        openvpn_execve_check(&argv, NULL, 0, "MacOS X 'remove inet6 route' failed (non-critical)");

     }

+

+    close_tun_generic(tt);

+    free(tt);

+    argv_reset(&argv);

+    gc_free(&gc);

 }

 int

@@ -3335,14 +3332,11 @@ open_tun(const char *dev, const char *dev_type, const char *dev_node, struct tun

 void

 close_tun(struct tuntap *tt)

 {

+    ASSERT(tt);

+

     struct argv argv = argv_new();

     struct env_set *es = env_set_create(NULL);

-    if (!tt)

-    {

-        return;

-    }

-

     /* persistent devices need IP address unconfig, others need destroyal

      */

     if (tt->persistent_if)

@@ -6181,104 +6175,103 @@ tun_show_debug(struct tuntap *tt)

 void

 close_tun(struct tuntap *tt)

 {

+    ASSERT(tt);

+

     struct gc_arena gc = gc_new();

-    if (tt)

+    if (tt->did_ifconfig_ipv6_setup)

     {

-        if (tt->did_ifconfig_ipv6_setup)

-        {

-            /* remove route pointing to interface */

-            delete_route_connected_v6_net(tt, NULL);

+        /* remove route pointing to interface */

+        delete_route_connected_v6_net(tt, NULL);

-            if (tt->options.msg_channel)

+        if (tt->options.msg_channel)

+        {

+            do_address_service(false, AF_INET6, tt);

+            if (tt->options.dns6_len > 0)

             {

-                do_address_service(false, AF_INET6, tt);

-                if (tt->options.dns6_len > 0)

-                {

-                    do_dns6_service(false, tt);

-                }

+                do_dns6_service(false, tt);

             }

-            else

-            {

-                const char *ifconfig_ipv6_local;

-                struct argv argv = argv_new();

+        }

+        else

+        {

+            const char *ifconfig_ipv6_local;

+            struct argv argv = argv_new();

-                /* "store=active" is needed in Windows 8(.1) to delete the

-                 * address we added (pointed out by Cedric Tabary).

-                 */

+            /* "store=active" is needed in Windows 8(.1) to delete the

+             * address we added (pointed out by Cedric Tabary).

+             */

+

+            /* netsh interface ipv6 delete address \"%s\" %s */

+            ifconfig_ipv6_local = print_in6_addr(tt->local_ipv6, 0,  &gc);

+            argv_printf(&argv,

+                        "%s%sc interface ipv6 delete address %s %s store=active",

+                        get_win_sys_path(),

+                        NETSH_PATH_SUFFIX,

+                        tt->actual_name,

+                        ifconfig_ipv6_local);

-                /* netsh interface ipv6 delete address \"%s\" %s */

-                ifconfig_ipv6_local = print_in6_addr(tt->local_ipv6, 0,  &gc);

+            netsh_command(&argv, 1, M_WARN);

+

+            /* delete ipv6 dns servers if any were set */

+            if (tt->options.dns6_len > 0)

+            {

                 argv_printf(&argv,

-                            "%s%sc interface ipv6 delete address %s %s store=active",

+                            "%s%sc interface ipv6 delete dns %s all",

                             get_win_sys_path(),

                             NETSH_PATH_SUFFIX,

-                            tt->actual_name,

-                            ifconfig_ipv6_local);

-

+                            tt->actual_name);

                 netsh_command(&argv, 1, M_WARN);

-

-                /* delete ipv6 dns servers if any were set */

-                if (tt->options.dns6_len > 0)

-                {

-                    argv_printf(&argv,

-                                "%s%sc interface ipv6 delete dns %s all",

-                                get_win_sys_path(),

-                                NETSH_PATH_SUFFIX,

-                                tt->actual_name);

-                    netsh_command(&argv, 1, M_WARN);

-                }

-                argv_reset(&argv);

             }

+            argv_reset(&argv);

         }

+    }

 #if 1

-        if (tt->ipapi_context_defined)

+    if (tt->ipapi_context_defined)

+    {

+        DWORD status;

+        if ((status = DeleteIPAddress(tt->ipapi_context)) != NO_ERROR)

         {

-            DWORD status;

-            if ((status = DeleteIPAddress(tt->ipapi_context)) != NO_ERROR)

-            {

-                msg(M_WARN, "Warning: DeleteIPAddress[%u] failed on TAP-Windows adapter, status=%u : %s",

-                    (unsigned int)tt->ipapi_context,

-                    (unsigned int)status,

-                    strerror_win32(status, &gc));

-            }

+            msg(M_WARN, "Warning: DeleteIPAddress[%u] failed on TAP-Windows adapter, status=%u : %s",

+                (unsigned int)tt->ipapi_context,

+                (unsigned int)status,

+                strerror_win32(status, &gc));

         }

+    }

 #endif

-        dhcp_release(tt);

+    dhcp_release(tt);

-        if (tt->hand != NULL)

+    if (tt->hand != NULL)

+    {

+        dmsg(D_WIN32_IO_LOW, "Attempting CancelIO on TAP-Windows adapter");

+        if (!CancelIo(tt->hand))

         {

-            dmsg(D_WIN32_IO_LOW, "Attempting CancelIO on TAP-Windows adapter");

-            if (!CancelIo(tt->hand))

-            {

-                msg(M_WARN | M_ERRNO, "Warning: CancelIO failed on TAP-Windows adapter");

-            }

+            msg(M_WARN | M_ERRNO, "Warning: CancelIO failed on TAP-Windows adapter");

         }

+    }

-        dmsg(D_WIN32_IO_LOW, "Attempting close of overlapped read event on TAP-Windows adapter");

-        overlapped_io_close(&tt->reads);

-

-        dmsg(D_WIN32_IO_LOW, "Attempting close of overlapped write event on TAP-Windows adapter");

-        overlapped_io_close(&tt->writes);

+    dmsg(D_WIN32_IO_LOW, "Attempting close of overlapped read event on TAP-Windows adapter");

+    overlapped_io_close(&tt->reads);

-        if (tt->hand != NULL)

-        {

-            dmsg(D_WIN32_IO_LOW, "Attempting CloseHandle on TAP-Windows adapter");

-            if (!CloseHandle(tt->hand))

-            {

-                msg(M_WARN | M_ERRNO, "Warning: CloseHandle failed on TAP-Windows adapter");

-            }

-        }

+    dmsg(D_WIN32_IO_LOW, "Attempting close of overlapped write event on TAP-Windows adapter");

+    overlapped_io_close(&tt->writes);

-        if (tt->actual_name)

+    if (tt->hand != NULL)

+    {

+        dmsg(D_WIN32_IO_LOW, "Attempting CloseHandle on TAP-Windows adapter");

+        if (!CloseHandle(tt->hand))

         {

-            free(tt->actual_name);

+            msg(M_WARN | M_ERRNO, "Warning: CloseHandle failed on TAP-Windows adapter");

         }

+    }

-        clear_tuntap(tt);

-        free(tt);

+    if (tt->actual_name)

+    {

+        free(tt->actual_name);

     }

+

+    clear_tuntap(tt);

+    free(tt);

     gc_free(&gc);

 }

@@ -6357,11 +6350,10 @@ open_tun(const char *dev, const char *dev_type, const char *dev_node, struct tun

 void

 close_tun(struct tuntap *tt)

 {

-    if (tt)

-    {

-        close_tun_generic(tt);

-        free(tt);

-    }

+    ASSERT(tt);

+

+    close_tun_generic(tt);

+    free(tt);

 }

 int