Warn about performance if using TAP-Windows >=9.21.
[tinc] / src / mingw / device.c
index 85c0c7b..e95878c 100644 (file)
@@ -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
 
 int device_fd = -1;
 static HANDLE device_handle = INVALID_HANDLE_VALUE;
+static io_t device_read_io;
+static OVERLAPPED device_read_overlapped;
+static vpn_packet_t device_read_packet;
 char *device = NULL;
 char *iface = NULL;
 static char *device_info = NULL;
 
-static uint64_t device_total_in = 0;
-static uint64_t device_total_out = 0;
-
 extern char *myport;
 
-static DWORD WINAPI tapreader(void *bla) {
-       int status;
-       DWORD len;
-       OVERLAPPED overlapped;
-       vpn_packet_t packet;
-
-       logger(DEBUG_ALWAYS, LOG_DEBUG, "Tap reader running");
-
-       /* Read from tap device and send to parent */
+static void device_issue_read() {
+       device_read_overlapped.Offset = 0;
+       device_read_overlapped.OffsetHigh = 0;
 
-       overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
-
-       for(;;) {
-               overlapped.Offset = 0;
-               overlapped.OffsetHigh = 0;
-               ResetEvent(overlapped.hEvent);
-
-               status = ReadFile(device_handle, (void *)packet.data, MTU, &len, &overlapped);
-
-               if(!status) {
-                       if(GetLastError() == ERROR_IO_PENDING) {
-                               WaitForSingleObject(overlapped.hEvent, INFINITE);
-                               if(!GetOverlappedResult(device_handle, &overlapped, &len, FALSE))
-                                       continue;
-                       } else {
+       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));
-                               return -1;
-                       }
+                       break;
                }
 
-               EnterCriticalSection(&mutex);
-               packet.len = len;
-               packet.priority = 0;
-               route(myself, &packet);
-               event_flush_output();
-               LeaveCriticalSection(&mutex);
+               device_read_packet.len = len;
+               device_read_packet.priority = 0;
+               route(myself, &device_read_packet);
+       }
+}
+
+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));
+               return;
        }
+
+       device_read_packet.len = len;
+       device_read_packet.priority = 0;
+       route(myself, &device_read_packet);
+       device_issue_read();
 }
 
 static bool setup_device(void) {
@@ -94,12 +91,10 @@ static bool setup_device(void) {
        char adaptername[1024];
        char tapname[1024];
        DWORD len;
-       unsigned long status;
 
        bool found = false;
 
        int err;
-       HANDLE thread;
 
        get_config_string(lookup_config(config_tree, "Device"), &device);
        get_config_string(lookup_config(config_tree, "Interface"), &iface);
@@ -180,6 +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)) {
@@ -191,25 +205,35 @@ static bool setup_device(void) {
                overwrite_mac = 1;
        }
 
-       /* Start the tap reader */
+       device_info = "Windows tap device";
 
-       thread = CreateThread(NULL, 0, tapreader, NULL, 0, NULL);
+       logger(DEBUG_ALWAYS, LOG_INFO, "%s (%s) is a %s", device, iface, device_info);
 
-       if(!thread) {
-               logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "CreateThread", winerror(GetLastError()));
-               return false;
-       }
+       return true;
+}
 
-       /* Set media status for newer TAP-Win32 devices */
+static void enable_device(void) {
+       logger(DEBUG_ALWAYS, LOG_INFO, "Enabling %s", device_info);
 
-       status = true;
+       ULONG status = 1;
+       DWORD len;
        DeviceIoControl(device_handle, TAP_IOCTL_SET_MEDIA_STATUS, &status, sizeof status, &status, sizeof status, &len, NULL);
 
-       device_info = "Windows tap device";
+       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();
+}
 
-       logger(DEBUG_ALWAYS, LOG_INFO, "%s (%s) is a %s", device, iface, device_info);
+static void disable_device(void) {
+       logger(DEBUG_ALWAYS, LOG_INFO, "Disabling %s", device_info);
 
-       return true;
+       io_del(&device_read_io);
+       CancelIo(device_handle);
+       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);
 }
 
 static void close_device(void) {
@@ -231,13 +255,11 @@ 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;
        }
 
-       device_total_out += packet->len;
-
        return true;
 }
 
@@ -246,4 +268,6 @@ const devops_t os_devops = {
        .close = close_device,
        .read = read_packet,
        .write = write_packet,
+       .enable = enable_device,
+       .disable = disable_device,
 };