Add warnings for bad combinations of Device and Interface.

[tinc] / src / mingw / device.c

diff --git a/src/mingw/device.c b/src/mingw/device.c
index 56203d4..b77282a 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
@@ -43,44 +43,55 @@ static uint64_t device_total_in = 0;
 static uint64_t device_total_out = 0;
 
 extern char *myport;
+OVERLAPPED r_overlapped;
+OVERLAPPED w_overlapped;
 
 static DWORD WINAPI tapreader(void *bla) {
        int status;
        DWORD len;
-       OVERLAPPED overlapped;
        vpn_packet_t packet;
+       int errors = 0;
 
        logger(LOG_DEBUG, "Tap reader running");
 
        /* Read from tap device and send to parent */
 
-       overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
+       r_overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
 
        for(;;) {
-               overlapped.Offset = 0;
-               overlapped.OffsetHigh = 0;
-               ResetEvent(overlapped.hEvent);
+               ResetEvent(r_overlapped.hEvent);
 
-               status = ReadFile(device_handle, packet.data, MTU, &len, &overlapped);
+               status = ReadFile(device_handle, packet.data, MTU, &len, &r_overlapped);
 
                if(!status) {
                        if(GetLastError() == ERROR_IO_PENDING) {
-                               WaitForSingleObject(overlapped.hEvent, INFINITE);
-                               if(!GetOverlappedResult(device_handle, &overlapped, &len, FALSE))
+                               WaitForSingleObject(r_overlapped.hEvent, INFINITE);
+                               if(!GetOverlappedResult(device_handle, &r_overlapped, &len, FALSE))
                                        continue;
                        } else {
                                logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
                                           device, strerror(errno));
-                               return -1;
+                               errors++;
+                               if(errors >= 10) {
+                                       EnterCriticalSection(&mutex);
+                                       running = false;
+                                       LeaveCriticalSection(&mutex);
+                               }
+                               usleep(1000000);
+                               continue;
                        }
                }
 
-               EnterCriticalSection(&mutex);
+               errors = 0;
                packet.len = len;
                packet.priority = 0;
+
+               EnterCriticalSection(&mutex);
                route(myself, &packet);
                LeaveCriticalSection(&mutex);
        }
+
+       return 0;
 }
 
 static bool setup_device(void) {
@@ -102,6 +113,9 @@ static bool setup_device(void) {
        get_config_string(lookup_config(config_tree, "Device"), &device);
        get_config_string(lookup_config(config_tree, "Interface"), &iface);
 
+       if(device && interface)
+               logger(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)) {
@@ -189,6 +203,11 @@ static bool setup_device(void) {
                overwrite_mac = 1;
        }
 
+       /* Create overlapped events for tap I/O */
+
+       r_overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
+       w_overlapped.hEvent = CreateEvent(NULL, TRUE, TRUE, NULL);
+
        /* Start the tap reader */
 
        thread = CreateThread(NULL, 0, tapreader, NULL, 0, NULL);
@@ -223,14 +242,48 @@ static bool read_packet(vpn_packet_t *packet) {
 
 static bool write_packet(vpn_packet_t *packet) {
        DWORD lenout;
-       OVERLAPPED overlapped = {0};
+       static vpn_packet_t queue;
 
        ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
                           packet->len, device_info);
 
-       if(!WriteFile(device_handle, packet->data, packet->len, &lenout, &overlapped)) {
-               logger(LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(GetLastError()));
-               return false;
+       /* Check if there is something in progress */
+
+       if(queue.len) {
+               DWORD size;
+               BOOL success = GetOverlappedResult(device_handle, &w_overlapped, &size, FALSE);
+               if(success) {
+                       ResetEvent(&w_overlapped);
+                       queue.len = 0;
+               } else {
+                       int err = GetLastError();
+                       if(err != ERROR_IO_INCOMPLETE) {
+                               ifdebug(TRAFFIC) logger(LOG_DEBUG, "Error completing previously queued write: %s", winerror(err));
+                               ResetEvent(&w_overlapped);
+                               queue.len = 0;
+                       } else {
+                               ifdebug(TRAFFIC) logger(LOG_DEBUG, "Previous overlapped write still in progress");
+                               // drop this packet
+                               return true;
+                       }
+               }
+       }
+
+       /* Otherwise, try to write. */
+
+       memcpy(queue.data, packet->data, packet->len);
+
+       if(!WriteFile(device_handle, queue.data, packet->len, &lenout, &w_overlapped)) {
+               int err = GetLastError();
+               if(err != ERROR_IO_PENDING) {
+                       logger(LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(err));
+                       return false;
+               }
+               // Write is being done asynchronously.
+               queue.len = packet->len;
+       } else {
+               // Write was completed immediately.
+               ResetEvent(&w_overlapped);
        }
 
        device_total_out += packet->len;