Move ResetEvent() call before ReadFile().

Commit 313a752 changed the Windows device code such that ResetEvent() is
called on the read OVERLAPPED structure before GetOverlappedResult(), as
opposed to before ReadFile(). In [1] Guus pointed out that this doesn't
make a ton of sense, and I agree with him; it must have been an
oversight on my part when I wrote this code.

Surprisingly, none of this makes any difference in my testing, at least
with the standard TAP 9.0.0.9 driver. Nevertheless, this code is
probably wrong and fixing it will make me sleep better at night.

[1]: https://www.tinc-vpn.org/pipermail/tinc/2018-January/005091.html

diff --git a/src/mingw/device.c b/src/mingw/device.c
index 49d0cd341c8229785bd67035fa69c17d4259ff56..d90c69b0244622138422390c110ba7b3e7ea4c0e 100644 (file)
--- a/src/mingw/device.c
+++ b/src/mingw/device.c
@@ -54,6 +54,8 @@ static void device_issue_read() {
        int status;
 
        for(;;) {
+               ResetEvent(device_read_overlapped.hEvent);
+
                DWORD len;
                status = ReadFile(device_handle, (void *)device_read_packet.data, MTU, &len, &device_read_overlapped);
 
@@ -72,10 +74,7 @@ static void device_issue_read() {
 }
 
 static void device_handle_read(void *data, int flags) {
-       ResetEvent(device_read_overlapped.hEvent);
-
        DWORD len;
-
        if(!GetOverlappedResult(device_handle, &device_read_overlapped, &len, FALSE)) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Error getting read result from %s %s: %s", device_info,
                       device, strerror(errno));