[Openvpn-devel] Simplify iphlpapi.dll API calls

Message ID 20171012080720.7764-1-simon@rozman.si
State Accepted
Headers show
Series
  • [Openvpn-devel] Simplify iphlpapi.dll API calls
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Commit Message

Simon Rozman Oct. 12, 2017, 8:07 a.m.
Dynamically locating API function addresses at run-time using
GetProcAddress() was a leftover from the early days of the interactive
service development. It was required before `NTDDI_VERSION` was raised
from Windows XP to Windows Vista.

After NTDDI_VERSION API level was raised to NTDDI_VISTA, the direct
calling of Vista introduced API functions is possible and much
simpler.

This patch simplifies the code while in the same time it removes
controversial function type definitions that caused interactive service not to compile on MSVC.
---
 src/openvpnserv/interactive.c | 123 +-----------------------------------------
 1 file changed, 1 insertion(+), 122 deletions(-)

Comments

Selva Nair Oct. 13, 2017, 2:33 a.m. | #1
Hi,

Note to self: this is v2 of [PATCH 05/13]
https://www.mail-archive.com/openvpn-devel@lists.sourceforge
.net/msg15589.html

On Thu, Oct 12, 2017 at 4:07 AM, Simon Rozman <simon@rozman.si> wrote:

> Dynamically locating API function addresses at run-time using
> GetProcAddress() was a leftover from the early days of the interactive
> service development. It was required before `NTDDI_VERSION` was raised
> from Windows XP to Windows Vista.
>
> After NTDDI_VERSION API level was raised to NTDDI_VISTA, the direct
> calling of Vista introduced API functions is possible and much
> simpler.
>
> This patch simplifies the code while in the same time it removes
> controversial function type definitions that caused interactive service
> not to compile on MSVC.
> ---
>  src/openvpnserv/interactive.c | 123 +-----------------------------
> ------------
>  1 file changed, 1 insertion(+), 122 deletions(-)
>
> diff --git a/src/openvpnserv/interactive.c b/src/openvpnserv/interactive.c
> index a060a06..bb8c5f6 100644
> --- a/src/openvpnserv/interactive.c
> +++ b/src/openvpnserv/interactive.c
> @@ -549,23 +549,6 @@ InterfaceLuid(const char *iface_name, PNET_LUID luid)
>      LPWSTR wide_name;
>      int n;
>
> -    typedef NETIO_STATUS WINAPI (*ConvertInterfaceAliasToLuidFn)
> (LPCWSTR, PNET_LUID);
> -    static ConvertInterfaceAliasToLuidFn ConvertInterfaceAliasToLuid =
> NULL;
> -    if (!ConvertInterfaceAliasToLuid)
> -    {
> -        HMODULE iphlpapi = GetModuleHandle(TEXT("iphlpapi.dll"));
> -        if (iphlpapi == NULL)
> -        {
> -            return GetLastError();
> -        }
> -
> -        ConvertInterfaceAliasToLuid = (ConvertInterfaceAliasToLuidFn)
> GetProcAddress(iphlpapi, "ConvertInterfaceAliasToLuid");
> -        if (!ConvertInterfaceAliasToLuid)
> -        {
> -            return GetLastError();
> -        }
> -    }
> -
>      n = MultiByteToWideChar(CP_UTF8, 0, iface_name, -1, NULL, 0);
>      wide_name = malloc(n * sizeof(WCHAR));

     MultiByteToWideChar(CP_UTF8, 0, iface_name, -1, wide_name, n);
>

Not a fault of this patch, but malloc's return value not checked... Let's
address that in a separate patch.


> @@ -584,24 +567,6 @@ CmpAddress(LPVOID item, LPVOID address)
>  static DWORD
>  DeleteAddress(PMIB_UNICASTIPADDRESS_ROW addr_row)
>  {
> -    typedef NETIOAPI_API (*DeleteUnicastIpAddressEntryFn) (const
> PMIB_UNICASTIPADDRESS_ROW);
> -    static DeleteUnicastIpAddressEntryFn DeleteUnicastIpAddressEntry =
> NULL;
> -
> -    if (!DeleteUnicastIpAddressEntry)
> -    {
> -        HMODULE iphlpapi = GetModuleHandle(TEXT("iphlpapi.dll"));
> -        if (iphlpapi == NULL)
> -        {
> -            return GetLastError();
> -        }
> -
> -        DeleteUnicastIpAddressEntry = (DeleteUnicastIpAddressEntryFn)
> GetProcAddress(iphlpapi, "DeleteUnicastIpAddressEntry");
> -        if (!DeleteUnicastIpAddressEntry)
> -        {
> -            return GetLastError();
> -        }
> -    }
> -
>      return DeleteUnicastIpAddressEntry(addr_row);
>  }
>
> @@ -612,32 +577,6 @@ HandleAddressMessage(address_message_t *msg,
> undo_lists_t *lists)
>      PMIB_UNICASTIPADDRESS_ROW addr_row;
>      BOOL add = msg->header.type == msg_add_address;
>
> -    typedef NETIOAPI_API (*CreateUnicastIpAddressEntryFn) (const
> PMIB_UNICASTIPADDRESS_ROW);
> -    typedef NETIOAPI_API (*InitializeUnicastIpAddressEntryFn)
> (PMIB_UNICASTIPADDRESS_ROW);
> -    static CreateUnicastIpAddressEntryFn CreateUnicastIpAddressEntry =
> NULL;
> -    static InitializeUnicastIpAddressEntryFn
> InitializeUnicastIpAddressEntry = NULL;
> -
> -    if (!CreateUnicastIpAddressEntry || !InitializeUnicastIpAddressEntry)
> -    {
> -        HMODULE iphlpapi = GetModuleHandle(TEXT("iphlpapi.dll"));
> -        if (iphlpapi == NULL)
> -        {
> -            return GetLastError();
> -        }
> -
> -        CreateUnicastIpAddressEntry = (CreateUnicastIpAddressEntryFn)
> GetProcAddress(iphlpapi, "CreateUnicastIpAddressEntry");
> -        if (!CreateUnicastIpAddressEntry)
> -        {
> -            return GetLastError();
> -        }
> -
> -        InitializeUnicastIpAddressEntry = (InitializeUnicastIpAddressEntryFn)
> GetProcAddress(iphlpapi, "InitializeUnicastIpAddressEntry");
> -        if (!InitializeUnicastIpAddressEntry)
> -        {
> -            return GetLastError();
> -        }
> -    }
> -
>      addr_row = malloc(sizeof(*addr_row));
>      if (addr_row == NULL)
>      {
> @@ -706,24 +645,6 @@ CmpRoute(LPVOID item, LPVOID route)
>  static DWORD
>  DeleteRoute(PMIB_IPFORWARD_ROW2 fwd_row)
>  {
> -    typedef NETIOAPI_API (*DeleteIpForwardEntry2Fn) (PMIB_IPFORWARD_ROW2);
> -    static DeleteIpForwardEntry2Fn DeleteIpForwardEntry2 = NULL;
> -
> -    if (!DeleteIpForwardEntry2)
> -    {
> -        HMODULE iphlpapi = GetModuleHandle(TEXT("iphlpapi.dll"));
> -        if (iphlpapi == NULL)
> -        {
> -            return GetLastError();
> -        }
> -
> -        DeleteIpForwardEntry2 = (DeleteIpForwardEntry2Fn)
> GetProcAddress(iphlpapi, "DeleteIpForwardEntry2");
> -        if (!DeleteIpForwardEntry2)
> -        {
> -            return GetLastError();
> -        }
> -    }
> -
>      return DeleteIpForwardEntry2(fwd_row);
>  }
>
> @@ -734,24 +655,6 @@ HandleRouteMessage(route_message_t *msg,
> undo_lists_t *lists)
>      PMIB_IPFORWARD_ROW2 fwd_row;
>      BOOL add = msg->header.type == msg_add_route;
>
> -    typedef NETIOAPI_API (*CreateIpForwardEntry2Fn) (PMIB_IPFORWARD_ROW2);
> -    static CreateIpForwardEntry2Fn CreateIpForwardEntry2 = NULL;
> -
> -    if (!CreateIpForwardEntry2)
> -    {
> -        HMODULE iphlpapi = GetModuleHandle(TEXT("iphlpapi.dll"));
> -        if (iphlpapi == NULL)
> -        {
> -            return GetLastError();
> -        }
> -
> -        CreateIpForwardEntry2 = (CreateIpForwardEntry2Fn)
> GetProcAddress(iphlpapi, "CreateIpForwardEntry2");
> -        if (!CreateIpForwardEntry2)
> -        {
> -            return GetLastError();
> -        }
> -    }
> -
>      fwd_row = malloc(sizeof(*fwd_row));
>      if (fwd_row == NULL)
>      {
> @@ -820,36 +723,12 @@ out:
>  static DWORD
>  HandleFlushNeighborsMessage(flush_neighbors_message_t *msg)
>  {
> -    typedef NETIOAPI_API (*FlushIpNetTable2Fn) (ADDRESS_FAMILY,
> NET_IFINDEX);
> -    static FlushIpNetTable2Fn flush_fn = NULL;
> -
>      if (msg->family == AF_INET)
>      {
>          return FlushIpNetTable(msg->iface.index);
>      }
>
> -    if (!flush_fn)
> -    {
> -        HMODULE iphlpapi = GetModuleHandle(TEXT("iphlpapi.dll"));
> -        if (iphlpapi == NULL)
> -        {
> -            return GetLastError();
> -        }
> -
> -        flush_fn = (FlushIpNetTable2Fn) GetProcAddress(iphlpapi,
> "FlushIpNetTable2");
> -        if (!flush_fn)
> -        {
> -            if (GetLastError() == ERROR_PROC_NOT_FOUND)
> -            {
> -                return WSAEPFNOSUPPORT;
> -            }
> -            else
> -            {
> -                return GetLastError();
> -            }
> -        }
> -    }
> -    return flush_fn(msg->family, msg->iface.index);
> +    return FlushIpNetTable2(msg->family, msg->iface.index);
>  }
>

Looks good and cross-compiles without issues.

ACK

Selva
<div dir="ltr">Hi,<div><br></div><div>Note to self: this is v2 of [PATCH 05/13]</div><div><div class="gmail_extra"><a href="https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg15589.html" target="_blank">https://www.mail-archive.com/o<wbr>penvpn-devel@lists.sourceforge<wbr>.net/msg15589.html</a></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Oct 12, 2017 at 4:07 AM, Simon Rozman <span dir="ltr">&lt;<a href="mailto:simon@rozman.si" target="_blank">simon@rozman.si</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Dynamically locating API function addresses at run-time using<br>
GetProcAddress() was a leftover from the early days of the interactive<br>
service development. It was required before `NTDDI_VERSION` was raised<br>
from Windows XP to Windows Vista.<br>
<br>
After NTDDI_VERSION API level was raised to NTDDI_VISTA, the direct<br>
calling of Vista introduced API functions is possible and much<br>
simpler.<br>
<br>
This patch simplifies the code while in the same time it removes<br>
controversial function type definitions that caused interactive service not to compile on MSVC.<br>
---<br>
 src/openvpnserv/interactive.c | 123 +-----------------------------<wbr>------------<br>
 1 file changed, 1 insertion(+), 122 deletions(-)<br>
<br>
diff --git a/src/openvpnserv/interactive.<wbr>c b/src/openvpnserv/interactive.<wbr>c<br>
index a060a06..bb8c5f6 100644<br>
--- a/src/openvpnserv/interactive.<wbr>c<br>
+++ b/src/openvpnserv/interactive.<wbr>c<br>
@@ -549,23 +549,6 @@ InterfaceLuid(const char *iface_name, PNET_LUID luid)<br>
     LPWSTR wide_name;<br>
     int n;<br>
<br>
-    typedef NETIO_STATUS WINAPI (*ConvertInterfaceAliasToLuidF<wbr>n) (LPCWSTR, PNET_LUID);<br>
-    static ConvertInterfaceAliasToLuidFn ConvertInterfaceAliasToLuid = NULL;<br>
-    if (!ConvertInterfaceAliasToLuid)<br>
-    {<br>
-        HMODULE iphlpapi = GetModuleHandle(TEXT(&quot;iphlpapi<wbr>.dll&quot;));<br>
-        if (iphlpapi == NULL)<br>
-        {<br>
-            return GetLastError();<br>
-        }<br>
-<br>
-        ConvertInterfaceAliasToLuid = (ConvertInterfaceAliasToLuidFn<wbr>) GetProcAddress(iphlpapi, &quot;ConvertInterfaceAliasToLuid&quot;)<wbr>;<br>
-        if (!ConvertInterfaceAliasToLuid)<br>
-        {<br>
-            return GetLastError();<br>
-        }<br>
-    }<br>
-<br>
     n = MultiByteToWideChar(CP_UTF8, 0, iface_name, -1, NULL, 0);<br>
     wide_name = malloc(n * sizeof(WCHAR));</blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
     MultiByteToWideChar(CP_UTF8, 0, iface_name, -1, wide_name, n);<br></blockquote><div><br></div><div>Not a fault of this patch, but malloc&#39;s return value not checked... Let&#39;s</div><div>address that in a separate patch. </div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">@@ -584,24 +567,6 @@ CmpAddress(LPVOID item, LPVOID address)<br>
 static DWORD<br>
 DeleteAddress(PMIB_UNICASTIPA<wbr>DDRESS_ROW addr_row)<br>
 {<br>
-    typedef NETIOAPI_API (*DeleteUnicastIpAddressEntryF<wbr>n) (const PMIB_UNICASTIPADDRESS_ROW);<br>
-    static DeleteUnicastIpAddressEntryFn DeleteUnicastIpAddressEntry = NULL;<br>
-<br>
-    if (!DeleteUnicastIpAddressEntry)<br>
-    {<br>
-        HMODULE iphlpapi = GetModuleHandle(TEXT(&quot;iphlpapi<wbr>.dll&quot;));<br>
-        if (iphlpapi == NULL)<br>
-        {<br>
-            return GetLastError();<br>
-        }<br>
-<br>
-        DeleteUnicastIpAddressEntry = (DeleteUnicastIpAddressEntryFn<wbr>) GetProcAddress(iphlpapi, &quot;DeleteUnicastIpAddressEntry&quot;)<wbr>;<br>
-        if (!DeleteUnicastIpAddressEntry)<br>
-        {<br>
-            return GetLastError();<br>
-        }<br>
-    }<br>
-<br>
     return DeleteUnicastIpAddressEntry(ad<wbr>dr_row);<br>
 }<br>
<br>
@@ -612,32 +577,6 @@ HandleAddressMessage(address_m<wbr>essage_t *msg, undo_lists_t *lists)<br>
     PMIB_UNICASTIPADDRESS_ROW addr_row;<br>
     BOOL add = msg-&gt;header.type == msg_add_address;<br>
<br>
-    typedef NETIOAPI_API (*CreateUnicastIpAddressEntryF<wbr>n) (const PMIB_UNICASTIPADDRESS_ROW);<br>
-    typedef NETIOAPI_API (*InitializeUnicastIpAddressEn<wbr>tryFn) (PMIB_UNICASTIPADDRESS_ROW);<br>
-    static CreateUnicastIpAddressEntryFn CreateUnicastIpAddressEntry = NULL;<br>
-    static InitializeUnicastIpAddressEntr<wbr>yFn InitializeUnicastIpAddressEntr<wbr>y = NULL;<br>
-<br>
-    if (!CreateUnicastIpAddressEntry || !InitializeUnicastIpAddressEnt<wbr>ry)<br>
-    {<br>
-        HMODULE iphlpapi = GetModuleHandle(TEXT(&quot;iphlpapi<wbr>.dll&quot;));<br>
-        if (iphlpapi == NULL)<br>
-        {<br>
-            return GetLastError();<br>
-        }<br>
-<br>
-        CreateUnicastIpAddressEntry = (CreateUnicastIpAddressEntryFn<wbr>) GetProcAddress(iphlpapi, &quot;CreateUnicastIpAddressEntry&quot;)<wbr>;<br>
-        if (!CreateUnicastIpAddressEntry)<br>
-        {<br>
-            return GetLastError();<br>
-        }<br>
-<br>
-        InitializeUnicastIpAddressEntr<wbr>y = (InitializeUnicastIpAddressEnt<wbr>ryFn) GetProcAddress(iphlpapi, &quot;InitializeUnicastIpAddressEnt<wbr>ry&quot;);<br>
-        if (!InitializeUnicastIpAddressEn<wbr>try)<br>
-        {<br>
-            return GetLastError();<br>
-        }<br>
-    }<br>
-<br>
     addr_row = malloc(sizeof(*addr_row));<br>
     if (addr_row == NULL)<br>
     {<br>
@@ -706,24 +645,6 @@ CmpRoute(LPVOID item, LPVOID route)<br>
 static DWORD<br>
 DeleteRoute(PMIB_IPFORWARD_RO<wbr>W2 fwd_row)<br>
 {<br>
-    typedef NETIOAPI_API (*DeleteIpForwardEntry2Fn) (PMIB_IPFORWARD_ROW2);<br>
-    static DeleteIpForwardEntry2Fn DeleteIpForwardEntry2 = NULL;<br>
-<br>
-    if (!DeleteIpForwardEntry2)<br>
-    {<br>
-        HMODULE iphlpapi = GetModuleHandle(TEXT(&quot;iphlpapi<wbr>.dll&quot;));<br>
-        if (iphlpapi == NULL)<br>
-        {<br>
-            return GetLastError();<br>
-        }<br>
-<br>
-        DeleteIpForwardEntry2 = (DeleteIpForwardEntry2Fn) GetProcAddress(iphlpapi, &quot;DeleteIpForwardEntry2&quot;);<br>
-        if (!DeleteIpForwardEntry2)<br>
-        {<br>
-            return GetLastError();<br>
-        }<br>
-    }<br>
-<br>
     return DeleteIpForwardEntry2(fwd_row)<wbr>;<br>
 }<br>
<br>
@@ -734,24 +655,6 @@ HandleRouteMessage(route_messa<wbr>ge_t *msg, undo_lists_t *lists)<br>
     PMIB_IPFORWARD_ROW2 fwd_row;<br>
     BOOL add = msg-&gt;header.type == msg_add_route;<br>
<br>
-    typedef NETIOAPI_API (*CreateIpForwardEntry2Fn) (PMIB_IPFORWARD_ROW2);<br>
-    static CreateIpForwardEntry2Fn CreateIpForwardEntry2 = NULL;<br>
-<br>
-    if (!CreateIpForwardEntry2)<br>
-    {<br>
-        HMODULE iphlpapi = GetModuleHandle(TEXT(&quot;iphlpapi<wbr>.dll&quot;));<br>
-        if (iphlpapi == NULL)<br>
-        {<br>
-            return GetLastError();<br>
-        }<br>
-<br>
-        CreateIpForwardEntry2 = (CreateIpForwardEntry2Fn) GetProcAddress(iphlpapi, &quot;CreateIpForwardEntry2&quot;);<br>
-        if (!CreateIpForwardEntry2)<br>
-        {<br>
-            return GetLastError();<br>
-        }<br>
-    }<br>
-<br>
     fwd_row = malloc(sizeof(*fwd_row));<br>
     if (fwd_row == NULL)<br>
     {<br>
@@ -820,36 +723,12 @@ out:<br>
 static DWORD<br>
 HandleFlushNeighborsMessage(f<wbr>lush_neighbors_message_t *msg)<br>
 {<br>
-    typedef NETIOAPI_API (*FlushIpNetTable2Fn) (ADDRESS_FAMILY, NET_IFINDEX);<br>
-    static FlushIpNetTable2Fn flush_fn = NULL;<br>
-<br>
     if (msg-&gt;family == AF_INET)<br>
     {<br>
         return FlushIpNetTable(msg-&gt;iface.ind<wbr>ex);<br>
     }<br>
<br>
-    if (!flush_fn)<br>
-    {<br>
-        HMODULE iphlpapi = GetModuleHandle(TEXT(&quot;iphlpapi<wbr>.dll&quot;));<br>
-        if (iphlpapi == NULL)<br>
-        {<br>
-            return GetLastError();<br>
-        }<br>
-<br>
-        flush_fn = (FlushIpNetTable2Fn) GetProcAddress(iphlpapi, &quot;FlushIpNetTable2&quot;);<br>
-        if (!flush_fn)<br>
-        {<br>
-            if (GetLastError() == ERROR_PROC_NOT_FOUND)<br>
-            {<br>
-                return WSAEPFNOSUPPORT;<br>
-            }<br>
-            else<br>
-            {<br>
-                return GetLastError();<br>
-            }<br>
-        }<br>
-    }<br>
-    return flush_fn(msg-&gt;family, msg-&gt;iface.index);<br>
+    return FlushIpNetTable2(msg-&gt;family, msg-&gt;iface.index);<br>
 }<br></blockquote><div><br></div><div>Looks good and cross-compiles without issues.</div><div><br></div><div>ACK</div><div><br></div><div>Selva</div></div></div></div></div>
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Gert Doering Oct. 14, 2017, 9:03 p.m. | #2
I like patches that *remove* lots of lines of code :-)

Your patch has been applied to the master and release/2.4 branch.

commit a5d73667ffebea93960c135322aa3a8d0fd70d7a (master)
commit c5f0ccf1376b6c7e1fe58c87a67b009be3ac9361 (release/2.4)
Author: Simon Rozman
Date:   Thu Oct 12 10:07:20 2017 +0200

     Simplify iphlpapi.dll API calls

     Acked-by: Selva Nair <selva.nair@gmail.com>
     Message-Id: <20171012080720.7764-1-simon@rozman.si>
     URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg15614.html
     Signed-off-by: Gert Doering <gert@greenie.muc.de>


--
kind regards,

Gert Doering


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Patch

diff --git a/src/openvpnserv/interactive.c b/src/openvpnserv/interactive.c
index a060a06..bb8c5f6 100644
--- a/src/openvpnserv/interactive.c
+++ b/src/openvpnserv/interactive.c
@@ -549,23 +549,6 @@  InterfaceLuid(const char *iface_name, PNET_LUID luid)
     LPWSTR wide_name;
     int n;
 
-    typedef NETIO_STATUS WINAPI (*ConvertInterfaceAliasToLuidFn) (LPCWSTR, PNET_LUID);
-    static ConvertInterfaceAliasToLuidFn ConvertInterfaceAliasToLuid = NULL;
-    if (!ConvertInterfaceAliasToLuid)
-    {
-        HMODULE iphlpapi = GetModuleHandle(TEXT("iphlpapi.dll"));
-        if (iphlpapi == NULL)
-        {
-            return GetLastError();
-        }
-
-        ConvertInterfaceAliasToLuid = (ConvertInterfaceAliasToLuidFn) GetProcAddress(iphlpapi, "ConvertInterfaceAliasToLuid");
-        if (!ConvertInterfaceAliasToLuid)
-        {
-            return GetLastError();
-        }
-    }
-
     n = MultiByteToWideChar(CP_UTF8, 0, iface_name, -1, NULL, 0);
     wide_name = malloc(n * sizeof(WCHAR));
     MultiByteToWideChar(CP_UTF8, 0, iface_name, -1, wide_name, n);
@@ -584,24 +567,6 @@  CmpAddress(LPVOID item, LPVOID address)
 static DWORD
 DeleteAddress(PMIB_UNICASTIPADDRESS_ROW addr_row)
 {
-    typedef NETIOAPI_API (*DeleteUnicastIpAddressEntryFn) (const PMIB_UNICASTIPADDRESS_ROW);
-    static DeleteUnicastIpAddressEntryFn DeleteUnicastIpAddressEntry = NULL;
-
-    if (!DeleteUnicastIpAddressEntry)
-    {
-        HMODULE iphlpapi = GetModuleHandle(TEXT("iphlpapi.dll"));
-        if (iphlpapi == NULL)
-        {
-            return GetLastError();
-        }
-
-        DeleteUnicastIpAddressEntry = (DeleteUnicastIpAddressEntryFn) GetProcAddress(iphlpapi, "DeleteUnicastIpAddressEntry");
-        if (!DeleteUnicastIpAddressEntry)
-        {
-            return GetLastError();
-        }
-    }
-
     return DeleteUnicastIpAddressEntry(addr_row);
 }
 
@@ -612,32 +577,6 @@  HandleAddressMessage(address_message_t *msg, undo_lists_t *lists)
     PMIB_UNICASTIPADDRESS_ROW addr_row;
     BOOL add = msg->header.type == msg_add_address;
 
-    typedef NETIOAPI_API (*CreateUnicastIpAddressEntryFn) (const PMIB_UNICASTIPADDRESS_ROW);
-    typedef NETIOAPI_API (*InitializeUnicastIpAddressEntryFn) (PMIB_UNICASTIPADDRESS_ROW);
-    static CreateUnicastIpAddressEntryFn CreateUnicastIpAddressEntry = NULL;
-    static InitializeUnicastIpAddressEntryFn InitializeUnicastIpAddressEntry = NULL;
-
-    if (!CreateUnicastIpAddressEntry || !InitializeUnicastIpAddressEntry)
-    {
-        HMODULE iphlpapi = GetModuleHandle(TEXT("iphlpapi.dll"));
-        if (iphlpapi == NULL)
-        {
-            return GetLastError();
-        }
-
-        CreateUnicastIpAddressEntry = (CreateUnicastIpAddressEntryFn) GetProcAddress(iphlpapi, "CreateUnicastIpAddressEntry");
-        if (!CreateUnicastIpAddressEntry)
-        {
-            return GetLastError();
-        }
-
-        InitializeUnicastIpAddressEntry = (InitializeUnicastIpAddressEntryFn) GetProcAddress(iphlpapi, "InitializeUnicastIpAddressEntry");
-        if (!InitializeUnicastIpAddressEntry)
-        {
-            return GetLastError();
-        }
-    }
-
     addr_row = malloc(sizeof(*addr_row));
     if (addr_row == NULL)
     {
@@ -706,24 +645,6 @@  CmpRoute(LPVOID item, LPVOID route)
 static DWORD
 DeleteRoute(PMIB_IPFORWARD_ROW2 fwd_row)
 {
-    typedef NETIOAPI_API (*DeleteIpForwardEntry2Fn) (PMIB_IPFORWARD_ROW2);
-    static DeleteIpForwardEntry2Fn DeleteIpForwardEntry2 = NULL;
-
-    if (!DeleteIpForwardEntry2)
-    {
-        HMODULE iphlpapi = GetModuleHandle(TEXT("iphlpapi.dll"));
-        if (iphlpapi == NULL)
-        {
-            return GetLastError();
-        }
-
-        DeleteIpForwardEntry2 = (DeleteIpForwardEntry2Fn) GetProcAddress(iphlpapi, "DeleteIpForwardEntry2");
-        if (!DeleteIpForwardEntry2)
-        {
-            return GetLastError();
-        }
-    }
-
     return DeleteIpForwardEntry2(fwd_row);
 }
 
@@ -734,24 +655,6 @@  HandleRouteMessage(route_message_t *msg, undo_lists_t *lists)
     PMIB_IPFORWARD_ROW2 fwd_row;
     BOOL add = msg->header.type == msg_add_route;
 
-    typedef NETIOAPI_API (*CreateIpForwardEntry2Fn) (PMIB_IPFORWARD_ROW2);
-    static CreateIpForwardEntry2Fn CreateIpForwardEntry2 = NULL;
-
-    if (!CreateIpForwardEntry2)
-    {
-        HMODULE iphlpapi = GetModuleHandle(TEXT("iphlpapi.dll"));
-        if (iphlpapi == NULL)
-        {
-            return GetLastError();
-        }
-
-        CreateIpForwardEntry2 = (CreateIpForwardEntry2Fn) GetProcAddress(iphlpapi, "CreateIpForwardEntry2");
-        if (!CreateIpForwardEntry2)
-        {
-            return GetLastError();
-        }
-    }
-
     fwd_row = malloc(sizeof(*fwd_row));
     if (fwd_row == NULL)
     {
@@ -820,36 +723,12 @@  out:
 static DWORD
 HandleFlushNeighborsMessage(flush_neighbors_message_t *msg)
 {
-    typedef NETIOAPI_API (*FlushIpNetTable2Fn) (ADDRESS_FAMILY, NET_IFINDEX);
-    static FlushIpNetTable2Fn flush_fn = NULL;
-
     if (msg->family == AF_INET)
     {
         return FlushIpNetTable(msg->iface.index);
     }
 
-    if (!flush_fn)
-    {
-        HMODULE iphlpapi = GetModuleHandle(TEXT("iphlpapi.dll"));
-        if (iphlpapi == NULL)
-        {
-            return GetLastError();
-        }
-
-        flush_fn = (FlushIpNetTable2Fn) GetProcAddress(iphlpapi, "FlushIpNetTable2");
-        if (!flush_fn)
-        {
-            if (GetLastError() == ERROR_PROC_NOT_FOUND)
-            {
-                return WSAEPFNOSUPPORT;
-            }
-            else
-            {
-                return GetLastError();
-            }
-        }
-    }
-    return flush_fn(msg->family, msg->iface.index);
+    return FlushIpNetTable2(msg->family, msg->iface.index);
 }
 
 static void