SslGetExtensions

// SCHANNEL.dll
#include <windows.h>

HRESULT SslGetExtensions(
    const BYTE* clientHello,
    DWORD clientHelloByteSize,
    SCH_EXTENSION_DATA* genericExtensions,
    BYTE genericExtensionsCount,
    DWORD* bytesToRead,
    SchGetExtensionsOptions flags
);

<DllImport("SCHANNEL.dll", ExactSpelling:=True)>
Public Shared Function SslGetExtensions(
    clientHello As IntPtr,   ' BYTE*
    clientHelloByteSize As UInteger,   ' DWORD
    genericExtensions As IntPtr,   ' SCH_EXTENSION_DATA* in/out
    genericExtensionsCount As Byte,   ' BYTE
    <Out> ByRef bytesToRead As UInteger,   ' DWORD* out
    flags As Integer   ' SchGetExtensionsOptions
) As Integer
End Function

' clientHello : BYTE*
' clientHelloByteSize : DWORD
' genericExtensions : SCH_EXTENSION_DATA* in/out
' genericExtensionsCount : BYTE
' bytesToRead : DWORD* out
' flags : SchGetExtensionsOptions
Declare PtrSafe Function SslGetExtensions Lib "schannel" ( _
    ByVal clientHello As LongPtr, _
    ByVal clientHelloByteSize As Long, _
    ByVal genericExtensions As LongPtr, _
    ByVal genericExtensionsCount As Byte, _
    ByRef bytesToRead As Long, _
    ByVal flags As Long) As Long
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

SslGetExtensions = ctypes.windll.schannel.SslGetExtensions
SslGetExtensions.restype = ctypes.c_int
SslGetExtensions.argtypes = [
    ctypes.POINTER(ctypes.c_ubyte),  # clientHello : BYTE*
    wintypes.DWORD,  # clientHelloByteSize : DWORD
    ctypes.c_void_p,  # genericExtensions : SCH_EXTENSION_DATA* in/out
    ctypes.c_ubyte,  # genericExtensionsCount : BYTE
    ctypes.POINTER(wintypes.DWORD),  # bytesToRead : DWORD* out
    ctypes.c_int,  # flags : SchGetExtensionsOptions
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('SCHANNEL.dll')
SslGetExtensions = Fiddle::Function.new(
  lib['SslGetExtensions'],
  [
    Fiddle::TYPE_VOIDP,  # clientHello : BYTE*
    -Fiddle::TYPE_INT,  # clientHelloByteSize : DWORD
    Fiddle::TYPE_VOIDP,  # genericExtensions : SCH_EXTENSION_DATA* in/out
    -Fiddle::TYPE_CHAR,  # genericExtensionsCount : BYTE
    Fiddle::TYPE_VOIDP,  # bytesToRead : DWORD* out
    Fiddle::TYPE_INT,  # flags : SchGetExtensionsOptions
  ],
  Fiddle::TYPE_INT)

#[link(name = "schannel")]
extern "system" {
    fn SslGetExtensions(
        clientHello: *const u8,  // BYTE*
        clientHelloByteSize: u32,  // DWORD
        genericExtensions: *mut SCH_EXTENSION_DATA,  // SCH_EXTENSION_DATA* in/out
        genericExtensionsCount: u8,  // BYTE
        bytesToRead: *mut u32,  // DWORD* out
        flags: i32  // SchGetExtensionsOptions
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("SCHANNEL.dll")]
public static extern int SslGetExtensions(IntPtr clientHello, uint clientHelloByteSize, IntPtr genericExtensions, byte genericExtensionsCount, out uint bytesToRead, int flags);
"@
$api = Add-Type -MemberDefinition $sig -Name 'SCHANNEL_SslGetExtensions' -Namespace Win32 -PassThru
# $api::SslGetExtensions(clientHello, clientHelloByteSize, genericExtensions, genericExtensionsCount, bytesToRead, flags)

#uselib "SCHANNEL.dll"
#func global SslGetExtensions "SslGetExtensions" sptr, sptr, sptr, sptr, sptr, sptr
; SslGetExtensions varptr(clientHello), clientHelloByteSize, varptr(genericExtensions), genericExtensionsCount, varptr(bytesToRead), flags   ; 戻り値は stat
; clientHello : BYTE* -> "sptr"
; clientHelloByteSize : DWORD -> "sptr"
; genericExtensions : SCH_EXTENSION_DATA* in/out -> "sptr"
; genericExtensionsCount : BYTE -> "sptr"
; bytesToRead : DWORD* out -> "sptr"
; flags : SchGetExtensionsOptions -> "sptr"
; ※HSP3.7は #func のため戻り値はシステム変数 stat に格納されます。

#uselib "SCHANNEL.dll"
#cfunc global SslGetExtensions "SslGetExtensions" var, int, var, int, var, int
; res = SslGetExtensions(clientHello, clientHelloByteSize, genericExtensions, genericExtensionsCount, bytesToRead, flags)
; clientHello : BYTE* -> "var"
; clientHelloByteSize : DWORD -> "int"
; genericExtensions : SCH_EXTENSION_DATA* in/out -> "var"
; genericExtensionsCount : BYTE -> "int"
; bytesToRead : DWORD* out -> "var"
; flags : SchGetExtensionsOptions -> "int"
; ※出力/バッファ引数は var 方式(変数を直接渡す)。varptr 方式にも切替可。

; HRESULT SslGetExtensions(BYTE* clientHello, DWORD clientHelloByteSize, SCH_EXTENSION_DATA* genericExtensions, BYTE genericExtensionsCount, DWORD* bytesToRead, SchGetExtensionsOptions flags)
#uselib "SCHANNEL.dll"
#cfunc global SslGetExtensions "SslGetExtensions" var, int, var, int, var, int
; res = SslGetExtensions(clientHello, clientHelloByteSize, genericExtensions, genericExtensionsCount, bytesToRead, flags)
; clientHello : BYTE* -> "var"
; clientHelloByteSize : DWORD -> "int"
; genericExtensions : SCH_EXTENSION_DATA* in/out -> "var"
; genericExtensionsCount : BYTE -> "int"
; bytesToRead : DWORD* out -> "var"
; flags : SchGetExtensionsOptions -> "int"
; ※出力/バッファ引数は var 方式(変数を直接渡す)。varptr 方式にも切替可。

import (
	"golang.org/x/sys/windows"
	"unsafe"
)

var (
	schannel = windows.NewLazySystemDLL("SCHANNEL.dll")
	procSslGetExtensions = schannel.NewProc("SslGetExtensions")
)

// clientHello (BYTE*), clientHelloByteSize (DWORD), genericExtensions (SCH_EXTENSION_DATA* in/out), genericExtensionsCount (BYTE), bytesToRead (DWORD* out), flags (SchGetExtensionsOptions)
r1, _, err := procSslGetExtensions.Call(
	uintptr(clientHello),
	uintptr(clientHelloByteSize),
	uintptr(genericExtensions),
	uintptr(genericExtensionsCount),
	uintptr(bytesToRead),
	uintptr(flags),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HRESULT

function SslGetExtensions(
  clientHello: Pointer;   // BYTE*
  clientHelloByteSize: DWORD;   // DWORD
  genericExtensions: Pointer;   // SCH_EXTENSION_DATA* in/out
  genericExtensionsCount: Byte;   // BYTE
  bytesToRead: Pointer;   // DWORD* out
  flags: Integer   // SchGetExtensionsOptions
): Integer; stdcall;
  external 'SCHANNEL.dll' name 'SslGetExtensions';

result := DllCall("SCHANNEL\SslGetExtensions"
    , "Ptr", clientHello   ; BYTE*
    , "UInt", clientHelloByteSize   ; DWORD
    , "Ptr", genericExtensions   ; SCH_EXTENSION_DATA* in/out
    , "UChar", genericExtensionsCount   ; BYTE
    , "Ptr", bytesToRead   ; DWORD* out
    , "Int", flags   ; SchGetExtensionsOptions
    , "Int")   ; return: HRESULT

●SslGetExtensions(clientHello, clientHelloByteSize, genericExtensions, genericExtensionsCount, bytesToRead, flags) = DLL("SCHANNEL.dll", "int SslGetExtensions(void*, dword, void*, byte, void*, int)")
# 呼び出し: SslGetExtensions(clientHello, clientHelloByteSize, genericExtensions, genericExtensionsCount, bytesToRead, flags)
# clientHello : BYTE* -> "void*"
# clientHelloByteSize : DWORD -> "dword"
# genericExtensions : SCH_EXTENSION_DATA* in/out -> "void*"
# genericExtensionsCount : BYTE -> "byte"
# bytesToRead : DWORD* out -> "void*"
# flags : SchGetExtensionsOptions -> "int"
# なでしこ1は32bit・ANSI(Shift_JIS)。文字列=char*(ANSI)、ポインタ/ハンドル=void*(4byte)。