/*
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
static HANDLE device_handle = INVALID_HANDLE_VALUE;
static io_t device_read_io;
static OVERLAPPED device_read_overlapped;
+static OVERLAPPED device_write_overlapped;
static vpn_packet_t device_read_packet;
+static vpn_packet_t device_write_packet;
char *device = NULL;
char *iface = NULL;
static char *device_info = NULL;
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);
}
}
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)) {
overwrite_mac = 1;
}
- /* Start the tap reader */
-
- io_add_event(&device_read_io, device_handle_read, NULL, CreateEvent(NULL, TRUE, FALSE, NULL));
- device_read_overlapped.hEvent = device_read_io.event;
- device_issue_read();
-
device_info = "Windows tap device";
logger(DEBUG_ALWAYS, LOG_INFO, "%s (%s) is a %s", device, iface, device_info);
static void enable_device(void) {
logger(DEBUG_ALWAYS, LOG_INFO, "Enabling %s", device_info);
+
ULONG status = 1;
DWORD len;
DeviceIoControl(device_handle, TAP_IOCTL_SET_MEDIA_STATUS, &status, sizeof status, &status, sizeof status, &len, NULL);
+
+ /* We don't use the write event directly, but GetOverlappedResult() does, internally. */
+
+ device_read_overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
+ device_write_overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
+
+ io_add_event(&device_read_io, device_handle_read, NULL, device_read_overlapped.hEvent);
+ device_issue_read();
}
static void disable_device(void) {
logger(DEBUG_ALWAYS, LOG_INFO, "Disabling %s", device_info);
- ULONG status = 0;
+
+ 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()));
+ if(device_write_packet.len > 0 && !GetOverlappedResult(device_handle, &device_write_overlapped, &len, TRUE) && GetLastError() != ERROR_OPERATION_ABORTED)
+ logger(DEBUG_ALWAYS, LOG_ERR, "Could not wait for %s %s write to cancel: %s", device_info, device, winerror(GetLastError()));
+ device_write_packet.len = 0;
+
+ CloseHandle(device_read_overlapped.hEvent);
+ CloseHandle(device_write_overlapped.hEvent);
+
+ ULONG status = 0;
DeviceIoControl(device_handle, TAP_IOCTL_SET_MEDIA_STATUS, &status, sizeof status, &status, sizeof status, &len, NULL);
}
static void close_device(void) {
- io_del(&device_read_io);
- CancelIo(device_handle);
- CloseHandle(device_read_overlapped.hEvent);
CloseHandle(device_handle); device_handle = INVALID_HANDLE_VALUE;
free(device); device = NULL;
static bool write_packet(vpn_packet_t *packet) {
DWORD outlen;
- OVERLAPPED overlapped = {0};
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(device_write_packet.len > 0) {
+ /* Make sure the previous write operation is finished before we start the next one;
+ otherwise we end up with multiple write ops referencing the same OVERLAPPED structure,
+ which according to MSDN is a no-no. */
+
+ if(!GetOverlappedResult(device_handle, &device_write_overlapped, &outlen, FALSE)) {
+ int log_level = (GetLastError() == ERROR_IO_INCOMPLETE) ? DEBUG_TRAFFIC : DEBUG_ALWAYS;
+ logger(log_level, LOG_ERR, "Error while checking previous write to %s %s: %s", device_info, device, winerror(GetLastError()));
+ return false;
+ }
+ }
+
+ /* Copy the packet, since the write operation might still be ongoing after we return. */
+
+ memcpy(&device_write_packet, packet, sizeof *packet);
+
+ if(WriteFile(device_handle, DATA(&device_write_packet), device_write_packet.len, &outlen, &device_write_overlapped))
+ device_write_packet.len = 0;
+ else if (GetLastError() != ERROR_IO_PENDING) {
logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(GetLastError()));
return false;
}