/*
device.c -- Interaction with Windows tap driver in a MinGW environment
Copyright (C) 2002-2005 Ivo Timmermans,
- 2002-2014 Guus Sliepen <guus@tinc-vpn.org>
+ 2002-2018 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;
+static const char *device_info = "Windows tap device";
extern char *myport;
static void device_issue_read() {
- device_read_overlapped.Offset = 0;
- device_read_overlapped.OffsetHigh = 0;
-
int status;
- for (;;) {
+
+ for(;;) {
+ ResetEvent(device_read_overlapped.hEvent);
+
DWORD len;
status = ReadFile(device_handle, (void *)device_read_packet.data, MTU, &len, &device_read_overlapped);
- if (!status) {
- if (GetLastError() != ERROR_IO_PENDING)
+
+ if(!status) {
+ if(GetLastError() != ERROR_IO_PENDING)
logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
- device, strerror(errno));
+ device, strerror(errno));
+
break;
}
}
static void device_handle_read(void *data, int flags) {
- ResetEvent(device_read_overlapped.hEvent);
+ (void)data;
+ (void)flags;
DWORD len;
- if (!GetOverlappedResult(device_handle, &device_read_overlapped, &len, FALSE)) {
+
+ 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));
+ device, strerror(errno));
+
+ if(GetLastError() != ERROR_IO_INCOMPLETE) {
+ /* Must reset event or it will keep firing. */
+ ResetEvent(device_read_overlapped.hEvent);
+ }
+
return;
}
get_config_string(lookup_config(config_tree, "Device"), &device);
get_config_string(lookup_config(config_tree, "Interface"), &iface);
+ if(device && iface) {
+ logger(DEBUG_ALWAYS, LOG_WARNING, "Warning: both Device and Interface specified, results may not be as expected");
+ }
+
/* Open registry and look for network adapters */
if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, NETWORK_CONNECTIONS_KEY, 0, KEY_READ, &key)) {
return false;
}
- for (i = 0; ; i++) {
- len = sizeof adapterid;
- if(RegEnumKeyEx(key, i, adapterid, &len, 0, 0, 0, NULL))
+ for(i = 0; ; i++) {
+ len = sizeof(adapterid);
+
+ if(RegEnumKeyEx(key, i, adapterid, &len, 0, 0, 0, NULL)) {
break;
+ }
/* Find out more about this adapter */
- snprintf(regpath, sizeof regpath, "%s\\%s\\Connection", NETWORK_CONNECTIONS_KEY, adapterid);
+ snprintf(regpath, sizeof(regpath), "%s\\%s\\Connection", NETWORK_CONNECTIONS_KEY, adapterid);
- if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, regpath, 0, KEY_READ, &key2))
+ if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, regpath, 0, KEY_READ, &key2)) {
continue;
+ }
- len = sizeof adaptername;
+ len = sizeof(adaptername);
err = RegQueryValueEx(key2, "Name", 0, 0, (LPBYTE)adaptername, &len);
RegCloseKey(key2);
- if(err)
+ if(err) {
continue;
+ }
if(device) {
if(!strcmp(device, adapterid)) {
found = true;
break;
- } else
+ } else {
continue;
+ }
}
if(iface) {
if(!strcmp(iface, adaptername)) {
found = true;
break;
- } else
+ } else {
continue;
+ }
}
- snprintf(tapname, sizeof tapname, USERMODEDEVICEDIR "%s" TAPSUFFIX, adapterid);
+ snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, adapterid);
device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_OVERLAPPED, 0);
+
if(device_handle != INVALID_HANDLE_VALUE) {
found = true;
break;
return false;
}
- if(!device)
+ if(!device) {
device = xstrdup(adapterid);
+ }
- if(!iface)
+ if(!iface) {
iface = xstrdup(adaptername);
+ }
/* Try to open the corresponding tap device */
if(device_handle == INVALID_HANDLE_VALUE) {
- snprintf(tapname, sizeof tapname, USERMODEDEVICEDIR "%s" TAPSUFFIX, device);
+ snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, device);
device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_OVERLAPPED, 0);
}
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 recommended 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)) {
+ if(!DeviceIoControl(device_handle, TAP_IOCTL_GET_MAC, mymac.x, sizeof(mymac.x), mymac.x, sizeof(mymac.x), &len, 0)) {
logger(DEBUG_ALWAYS, LOG_ERR, "Could not get MAC address from Windows tap device %s (%s): %s", device, iface, winerror(GetLastError()));
return false;
}
logger(DEBUG_ALWAYS, LOG_INFO, "%s (%s) is a %s", device, iface, device_info);
+ device_read_overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
+ device_write_overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
+
return true;
}
ULONG status = 1;
DWORD len;
- DeviceIoControl(device_handle, TAP_IOCTL_SET_MEDIA_STATUS, &status, sizeof status, &status, sizeof status, &len, NULL);
+ 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. */
- io_add_event(&device_read_io, device_handle_read, NULL, CreateEvent(NULL, TRUE, FALSE, NULL));
- device_read_overlapped.hEvent = device_read_io.event;
+ io_add_event(&device_read_io, device_handle_read, NULL, device_read_overlapped.hEvent);
device_issue_read();
}
logger(DEBUG_ALWAYS, LOG_INFO, "Disabling %s", device_info);
io_del(&device_read_io);
+
+ ULONG status = 0;
+ DWORD len;
+ DeviceIoControl(device_handle, TAP_IOCTL_SET_MEDIA_STATUS, &status, sizeof(status), &status, sizeof(status), &len, NULL);
+
+ /* Note that we don't try to cancel ongoing I/O here - we just stop listening.
+ This is because some TAP-Win32 drivers don't seem to handle cancellation very well,
+ especially when combined with other events such as the computer going to sleep - cases
+ were observed where the GetOverlappedResult() would just block indefinitely and never
+ return in that case. */
+}
+
+static void close_device(void) {
CancelIo(device_handle);
/* According to MSDN, CancelIo() does not necessarily wait for the operation to complete.
before we close the event it's referencing. */
DWORD len;
- if(!GetOverlappedResult(device_handle, &device_read_overlapped, &len, TRUE) && GetLastError() != ERROR_OPERATION_ABORTED)
+
+ 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);
+ 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()));
+ }
- ULONG status = 0;
- DeviceIoControl(device_handle, TAP_IOCTL_SET_MEDIA_STATUS, &status, sizeof status, &status, sizeof status, &len, NULL);
-}
+ device_write_packet.len = 0;
-static void close_device(void) {
- CloseHandle(device_handle); device_handle = INVALID_HANDLE_VALUE;
+ CloseHandle(device_read_overlapped.hEvent);
+ CloseHandle(device_write_overlapped.hEvent);
+
+ CloseHandle(device_handle);
+ device_handle = INVALID_HANDLE_VALUE;
- free(device); device = NULL;
- free(iface); iface = NULL;
+ free(device);
+ device = NULL;
+ free(iface);
+ iface = NULL;
device_info = NULL;
}
static bool read_packet(vpn_packet_t *packet) {
+ (void)packet;
return false;
}
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);
+ packet->len, device_info);
+
+ 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)) {
+ if(GetLastError() != ERROR_IO_INCOMPLETE) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Error completing previously queued write to %s %s: %s", device_info, device, winerror(GetLastError()));
+ } else {
+ logger(DEBUG_TRAFFIC, LOG_ERR, "Previous overlapped write to %s %s still in progress", device_info, device);
+ // drop this packet
+ return true;
+ }
+ }
+ }
+
+ /* Copy the packet, since the write operation might still be ongoing after we return. */
+
+ memcpy(&device_write_packet, packet, sizeof(*packet));
+
+ ResetEvent(device_write_overlapped.hEvent);
- if(!WriteFile(device_handle, DATA(packet), packet->len, &outlen, &overlapped)) {
+ if(WriteFile(device_handle, DATA(&device_write_packet), device_write_packet.len, &outlen, &device_write_overlapped)) {
+ // Write was completed immediately.
+ 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()));
+ device_write_packet.len = 0;
return false;
}
projects / tinc / blobdiff