1 files changed, 52 insertions, 0 deletions
diff --git a/include/internal/e_winsock.h b/include/internal/e_winsock.h
new file mode 100644
index 000000000000..72a38a529f5b
--- /dev/null
+++ b/include/internal/e_winsock.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2022 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#ifndef OSSL_E_WINSOCK_H
+# define OSSL_E_WINSOCK_H
+# pragma once
+
+# ifdef WINDOWS
+#  if !defined(_WIN32_WCE) && !defined(_WIN32_WINNT)
+      /*
+       * Defining _WIN32_WINNT here in e_winsock.h implies certain "discipline."
+       * Most notably we ought to check for availability of each specific
+       * routine that was introduced after denoted _WIN32_WINNT with
+       * GetProcAddress(). Normally newer functions are masked with higher
+       * _WIN32_WINNT in SDK headers. So that if you wish to use them in
+       * some module, you'd need to override _WIN32_WINNT definition in
+       * the target module in order to "reach for" prototypes, but replace
+       * calls to new functions with indirect calls. Alternatively it
+       * might be possible to achieve the goal by /DELAYLOAD-ing .DLLs
+       * and check for current OS version instead.
+       */
+#   define _WIN32_WINNT 0x0501
+#  endif
+#  if defined(_WIN32_WINNT) || defined(_WIN32_WCE)
+      /*
+       * Just like defining _WIN32_WINNT including winsock2.h implies
+       * certain "discipline" for maintaining [broad] binary compatibility.
+       * As long as structures are invariant among Winsock versions,
+       * it's sufficient to check for specific Winsock2 API availability
+       * at run-time [DSO_global_lookup is recommended]...
+       */
+#   include <winsock2.h>
+#   include <ws2tcpip.h>
+      /*
+       * Clang-based C++Builder 10.3.3 toolchains cannot find C inline
+       * definitions at link-time.  This header defines WspiapiLoad() as an
+       * __inline function.  https://quality.embarcadero.com/browse/RSP-33806
+       */
+#   if !defined(__BORLANDC__) || !defined(__clang__)
+#    include <wspiapi.h>
+#   endif
+      /* yes, they have to be #included prior to <windows.h> */
+#  endif
+#  include <windows.h>
+# endif
+#endif /* !(OSSL_E_WINSOCK_H) */