When disabling the Windows device, wait for pending reads to complete.

[tinc] / src / mingw / device.c

diff --git a/src/mingw/device.c b/src/mingw/device.c
index 6ee26e7..73da2f1 100644 (file)
--- a/src/mingw/device.c
+++ b/src/mingw/device.c
@@ -1,7 +1,7 @@
 /*
     device.c -- Interaction with Windows tap driver in a MinGW environment
     Copyright (C) 2002-2005 Ivo Timmermans,
-                  2002-2013 Guus Sliepen <guus@tinc-vpn.org>
+                  2002-2014 Guus Sliepen <guus@tinc-vpn.org>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -210,10 +210,18 @@ static void disable_device(void) {
 
        io_del(&device_read_io);
        CancelIo(device_handle);
+
+       /* According to MSDN, CancelIo() does not necessarily wait for the operation to complete.
+          To prevent race conditions, make sure the operation is complete
+          before we close the event it's referencing. */
+
+       DWORD len;
+       if(!GetOverlappedResult(device_handle, &device_read_overlapped, &len, TRUE) && GetLastError() != ERROR_OPERATION_ABORTED)
+               logger(DEBUG_ALWAYS, LOG_ERR, "Could not wait for %s %s read to cancel: %s", device_info, device, winerror(GetLastError()));
+
        CloseHandle(device_read_overlapped.hEvent);
 
        ULONG status = 0;
-       DWORD len;
        DeviceIoControl(device_handle, TAP_IOCTL_SET_MEDIA_STATUS, &status, sizeof status, &status, sizeof status, &len, NULL);
 }
 
@@ -236,7 +244,7 @@ static bool write_packet(vpn_packet_t *packet) {
        logger(DEBUG_TRAFFIC, LOG_DEBUG, "Writing packet of %d bytes to %s",
                           packet->len, device_info);
 
-       if(!WriteFile(device_handle, packet->data, packet->len, &outlen, &overlapped)) {
+       if(!WriteFile(device_handle, DATA(packet), packet->len, &outlen, &overlapped)) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(GetLastError()));
                return false;
        }