Proper type for variables and function arguments

The actual optval argument type is DWORD (boolean) for the SOL_SOCKET
socket option SO_REUSEADDR:
  https://docs.microsoft.com/windows/win32/winsock/sol-socket-socket-options

The type of the optlen argument of setsockopt() is "int":
  https://docs.microsoft.com/windows/win32/api/winsock/nf-winsock-setsockopt#syntax

The type of the namelen argument of getsockname() is "int *":
  https://docs.microsoft.com/windows/win32/api/winsock/nf-winsock-getsockname#syntax

After these changes, socklen_t is not used anymore. Therefore we can
revert from <w2stcpip.h> to <winsock2.h>.

Author: DimitriPapadopoulos

dummy_headers/windows.h

@@ -1,5 +1,6 @@
 typedef void* SOCKET;
 typedef unsigned int DWORD;
+typedef unsigned int GROUP;
 #define WSA_FLAG_OVERLAPPED 1
 extern void WSASetLastError(int);
 extern int WSAGetLastError();
@@ -8,24 +9,23 @@ extern int WSAGetLastError();
 #define AF_INET 33
 #define SOCK_STREAM 44
 #define IPPROTO_TCP 55
-#define INVALID_SOCKET 0
+#define INVALID_SOCKET (SOCKET)(~0)
 extern void* socket(int, int, int);
 struct sockaddr_in {
     int sin_family;
     struct { unsigned s_addr; } sin_addr;
     unsigned short sin_port;
 };
 struct sockaddr { int dummy; };
-typedef unsigned socklen_t;
 #define SOL_SOCKET 66
 #define SO_REUSEADDR 77
 #define INADDR_LOOPBACK 88
-extern int setsockopt(SOCKET, int, int, char*, unsigned);
-extern int bind(SOCKET, struct sockaddr*, unsigned);
-extern int getsockname(SOCKET, struct sockaddr*, socklen_t*);
+extern int setsockopt(SOCKET, int, int, const char*, int);
+extern int bind(SOCKET, const struct sockaddr*, int);
+extern int getsockname(SOCKET, struct sockaddr*, int*);
 extern int listen(SOCKET, int);
-extern SOCKET WSASocket(int, int, int, void*, int, int);
-extern int connect(SOCKET, struct sockaddr*, unsigned);
-extern SOCKET accept(SOCKET, void*, void*);
+extern SOCKET WSASocket(int, int, int, void*, GROUP, DWORD);
+extern int connect(SOCKET, const struct sockaddr*, int);
+extern SOCKET accept(SOCKET, struct sockaddr*, int*);
 extern int closesocket(SOCKET);
-extern unsigned htonl(unsigned);
+extern unsigned long htonl(unsigned long);

dummy_headers/ws2tcpip.h dummy_headers/winsock2.h

@@ -51,7 +51,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <string.h>
 
 #ifdef WIN32
-# include <ws2tcpip.h>  /* socklen_t, et al (MSVC20xx) */
+# include <winsock2.h>
 # include <windows.h>
 # include <io.h>
 #else
@@ -77,16 +77,16 @@ int dumb_socketpair(SOCKET socks[2], int make_overlapped)
        struct sockaddr addr;
     } a;
     SOCKET listener;
-    int e;
-    socklen_t addrlen = sizeof(a.inaddr);
+    int addrlen = (int) sizeof(a.inaddr);
     DWORD flags = (make_overlapped ? WSA_FLAG_OVERLAPPED : 0);
-    int reuse = 1;
+    DWORD reuse = 1;
+    int e;
 
     if (socks == 0) {
       WSASetLastError(WSAEINVAL);
       return SOCKET_ERROR;
     }
-    socks[0] = socks[1] = -1;
+    socks[0] = socks[1] = INVALID_SOCKET;
 
     listener = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
     if (listener == INVALID_SOCKET)
@@ -99,9 +99,9 @@ int dumb_socketpair(SOCKET socks[2], int make_overlapped)
 
     for (;;) {
         if (setsockopt(listener, SOL_SOCKET, SO_REUSEADDR,
-               (char*) &reuse, (socklen_t) sizeof(reuse)) == SOCKET_ERROR)
+               (const char*) &reuse, (int) sizeof(reuse)) == SOCKET_ERROR)
             break;
-        if  (bind(listener, &a.addr, sizeof(a.inaddr)) == SOCKET_ERROR)
+        if  (bind(listener, &a.addr, (int) sizeof(a.inaddr)) == SOCKET_ERROR)
             break;
 
         memset(&a, 0, sizeof(a));
@@ -118,7 +118,7 @@ int dumb_socketpair(SOCKET socks[2], int make_overlapped)
         socks[0] = WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0, flags);
         if (socks[0] == INVALID_SOCKET)
             break;
-        if (connect(socks[0], &a.addr, sizeof(a.inaddr)) == SOCKET_ERROR)
+        if (connect(socks[0], &a.addr, (int) sizeof(a.inaddr)) == SOCKET_ERROR)
             break;
 
         socks[1] = accept(listener, NULL, NULL);
@@ -134,7 +134,7 @@ int dumb_socketpair(SOCKET socks[2], int make_overlapped)
     closesocket(socks[0]);
     closesocket(socks[1]);
     WSASetLastError(e);
-    socks[0] = socks[1] = -1;
+    socks[0] = socks[1] = INVALID_SOCKET;
     return SOCKET_ERROR;
 }
 #else