Warn about performance if using TAP-Windows >=9.21.

[tinc] / src / mingw / device.c

diff --git a/src/mingw/device.c b/src/mingw/device.c
index 2ef0064..e95878c 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
@@ -49,11 +49,20 @@ static void device_issue_read() {
        device_read_overlapped.Offset = 0;
        device_read_overlapped.OffsetHigh = 0;
 
-       int status = ReadFile(device_handle, (void *)device_read_packet.data, MTU, NULL, &device_read_overlapped);
+       int status;
+       for (;;) {
+               DWORD len;
+               status = ReadFile(device_handle, (void *)device_read_packet.data, MTU, &len, &device_read_overlapped);
+               if (!status) {
+                       if (GetLastError() != ERROR_IO_PENDING)
+                               logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
+                                          device, strerror(errno));
+                       break;
+               }
 
-       if(!status && GetLastError() != ERROR_IO_PENDING) {
-               logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
-                          device, strerror(errno));
+               device_read_packet.len = len;
+               device_read_packet.priority = 0;
+               route(myself, &device_read_packet);
        }
 }
 
@@ -166,6 +175,25 @@ static bool setup_device(void) {
                return false;
        }
 
+       /* Get version information from tap device */
+
+       {
+               ULONG info[3] = {0};
+               DWORD len;
+               if(!DeviceIoControl(device_handle, TAP_IOCTL_GET_VERSION, &info, sizeof info, &info, sizeof info, &len, NULL))
+                       logger(DEBUG_ALWAYS, LOG_WARNING, "Could not get version information from Windows tap device %s (%s): %s", device, iface, winerror(GetLastError()));
+               else {
+                       logger(DEBUG_ALWAYS, LOG_INFO, "TAP-Windows driver version: %lu.%lu%s", info[0], info[1], info[2] ? " (DEBUG)" : "");
+
+                       /* Warn if using >=9.21. This is because starting from 9.21, TAP-Win32 seems to use a different, less efficient write path. */
+                       if(info[0] == 9 && info[1] >= 21)
+                               logger(DEBUG_ALWAYS, LOG_WARNING,
+                                       "You are using the newer (>= 9.0.0.21, NDIS6) series of TAP-Win32 drivers. "
+                                       "Using these drivers with tinc is not recommanded as it can result in poor performance. "
+                                       "You might want to revert back to 9.0.0.9 instead.");
+               }
+       }
+
        /* Get MAC address from tap device */
 
        if(!DeviceIoControl(device_handle, TAP_IOCTL_GET_MAC, mymac.x, sizeof mymac.x, mymac.x, sizeof mymac.x, &len, 0)) {
@@ -227,7 +255,7 @@ 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;
        }