[Openvpn-devel,v2,2/3] tun: always pass a valid tt pointer

Message ID 20180613122824.4207-3-a@unstable.cc
State Accepted
Headers show
Series
  • pre-ipv6-only clean up patchset
Related show

Commit Message

Antonio Quartulli June 13, 2018, 12:28 p.m.
From: Antonio Quartulli <antonio@openvpn.net>

This patch is a small "logic restyle" which basically moves the
check for "tt != NULL" outside of the various close_tun()
implementations and replaces it with an ASSERT.

This way the check is done only once and the function can rely
on the assumption that "tt" is always valid.

This change is mainly to improve the code style inside close_tun()
implementations by removing one level of indentation.

No functional change is present.

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

---

Changes from v1:
- remove ASSERT from solaris_error_close()
- remove "if (tt)" block from solaris_close_tun()
- restored "/* close and destroy */" comment in FreeBSD close_tun()


 src/openvpn/init.c |   7 +-
 src/openvpn/tun.c  | 501 ++++++++++++++++++++++-----------------------
 2 files changed, 252 insertions(+), 256 deletions(-)

Comments

Gert Doering June 13, 2018, 1:12 p.m. | #1
Acked-by: Gert Doering <gert@greenie.muc.de>

Makes the code more readable, doesn't change anything (check with 
"git show -w", otherwise all the whitespace change is non-helpful).

Note: there was a rebase fail in the "NetBSD" close_tun() function,
bringing back the gc_arena that v2 1/3 just dropped.  I've taken the
liberty to remove it again - it did not want to be there.

Your patch has been applied to the master branch.

commit 0bea472c98dca8b3470ef863fd90a63b6c79fa68
Author: Antonio Quartulli
Date:   Wed Jun 13 20:28:23 2018 +0800

     tun: always pass a valid tt pointer

     Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
     Acked-by: Gert Doering <gert@greenie.muc.de>
     Message-Id: <20180613122824.4207-3-a@unstable.cc>
     URL: https://www.mail-archive.com/search?l=mid&q=20180613122824.4207-3-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/init.c b/src/openvpn/init.c
index 36c1a4c4..b748357d 100644
--- a/src/openvpn/init.c
+++ b/src/openvpn/init.c
@@ -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);
diff --git a/src/openvpn/tun.c b/src/openvpn/tun.c
index 72506c4b..12b33ae7 100644
--- a/src/openvpn/tun.c
+++ b/src/openvpn/tun.c
@@ -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 +2671,33 @@  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 gc_arena gc = gc_new();
+    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 +2813,32 @@  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 +2929,10 @@  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 +3185,26 @@  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 +3333,11 @@  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 +6176,103 @@  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 +6351,10 @@  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