BSD-style lwIP TCP/IP stack support:

Allow compilation of libcurl and curl using BSD-style lwIP on Win32.

In order to compile libcurl and curl with this support it is necessary
to edit files lib/config-win32.h and src/config-win32.h and uncomment
a line to make definition of preprocessor symbol USE_LWIPSOCK visible.

Afterwards you can compile as usual.

In order to use compiled library with BSD-style lwIP TCP/IP stack in
your program it is mandatory that you include lwIP header file <lwip/opt.h>
before including <curl/curl.h> or <curl/multi.h>

Compilation has been verified with lwIP 1.4.0 and contrib-1.4.0 from:

http://download.savannah.gnu.org/releases/lwip/lwip-1.4.0.zip
http://download.savannah.gnu.org/releases/lwip/contrib-1.4.0.zip

Have fun!

include/curl/curl.h

@@ -56,7 +56,7 @@
 #include <time.h>
 
 #if defined(WIN32) && !defined(_WIN32_WCE) && !defined(__CYGWIN__)
-#if !(defined(_WINSOCKAPI_) || defined(_WINSOCK_H))
+#if !(defined(_WINSOCKAPI_) || defined(_WINSOCK_H) || defined(__LWIP_OPT_H__))
 /* The check above prevents the winsock2 inclusion if winsock.h already was
    included, since they can't co-exist without problems */
 #include <winsock2.h>
@@ -78,6 +78,10 @@
 #include <sys/socket.h>
 #endif
 
+#if defined(__LWIP_OPT_H__)
+#include <lwip/sockets.h>
+#endif
+
 #if !defined(WIN32) && !defined(__WATCOMC__) && !defined(__VXWORKS__)
 #include <sys/time.h>
 #endif

lib/config-win32.h

@@ -388,6 +388,31 @@
 /* Define this if you have struct timeval */
 #define HAVE_STRUCT_TIMEVAL 1
 
+/* ---------------------------------------------------------------- */
+/*               BSD-style lwIP TCP/IP stack SPECIFIC               */
+/* ---------------------------------------------------------------- */
+
+/* Define this to use BSD-style lwIP TCP/IP stack  */
+/* #define USE_LWIPSOCK 1 */
+
+#ifdef USE_LWIPSOCK
+#  undef USE_WINSOCK
+#  undef HAVE_WINSOCK_H
+#  undef HAVE_WINSOCK2_H
+#  undef HAVE_WS2TCPIP_H
+#  undef HAVE_ERRNO_H
+#  undef HAVE_GETHOSTNAME
+#  undef HAVE_GETNAMEINFO
+#  undef LWIP_POSIX_SOCKETS_IO_NAMES
+#  define HAVE_FREEADDRINFO
+#  define HAVE_GETADDRINFO
+#  define HAVE_GETHOSTBYNAME
+#  define HAVE_GETHOSTBYNAME_R
+#  define HAVE_GETHOSTBYNAME_R_6
+#  define LWIP_POSIX_SOCKETS_IO_NAMES 0
+#  define SOCKET int
+#endif
+
 /* ---------------------------------------------------------------- */
 /*                        Watt-32 tcp/ip SPECIFIC                   */
 /* ---------------------------------------------------------------- */

lib/setup.h

@@ -251,6 +251,11 @@
 #  endif
 #endif
 
+#ifdef USE_LWIPSOCK
+#  include <lwip/sockets.h>
+#  include <lwip/netdb.h>
+#endif
+
 #ifdef HAVE_EXTRA_STRICMP_H
 #  include <extra/stricmp.h>
 #endif

src/config-win32.h

@@ -262,6 +262,31 @@
 /* Define this if struct sockaddr_in6 has the sin6_scope_id member */
 #define HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID 1
 
+/* ---------------------------------------------------------------- */
+/*               BSD-style lwIP TCP/IP stack SPECIFIC               */
+/* ---------------------------------------------------------------- */
+
+/* Define this to use BSD-style lwIP TCP/IP stack  */
+/* #define USE_LWIPSOCK 1 */
+
+#ifdef USE_LWIPSOCK
+#  undef USE_WINSOCK
+#  undef HAVE_WINSOCK_H
+#  undef HAVE_WINSOCK2_H
+#  undef HAVE_WS2TCPIP_H
+#  undef HAVE_ERRNO_H
+#  undef HAVE_GETHOSTNAME
+#  undef HAVE_GETNAMEINFO
+#  undef LWIP_POSIX_SOCKETS_IO_NAMES
+#  define HAVE_FREEADDRINFO
+#  define HAVE_GETADDRINFO
+#  define HAVE_GETHOSTBYNAME
+#  define HAVE_GETHOSTBYNAME_R
+#  define HAVE_GETHOSTBYNAME_R_6
+#  define LWIP_POSIX_SOCKETS_IO_NAMES 0
+#  define SOCKET int
+#endif
+
 /* ---------------------------------------------------------------- */
 /*                        Watt-32 tcp/ip SPECIFIC                   */
 /* ---------------------------------------------------------------- */

src/setup.h

@@ -135,6 +135,11 @@
 #  endif
 #endif
 
+#ifdef USE_LWIPSOCK
+#  include <lwip/sockets.h>
+#  include <lwip/netdb.h>
+#endif
+
 #ifdef TPF
 #  include <sys/socket.h>
    /* change which select is used for the curl command line tool */