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Use a mutex to allow the TAP reader to process packets faster on Windows.

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The TAP-Win32 device is not a socket, and select() under Windows only works
with sockets.  Tinc used a separate thread to read from the TAP-Win32 device,
and passed this via a local socket to the main thread which could then select()
from it. We now use a global mutex, which is only unlocked when the main thread
is waiting for select(), to allow the TAP reader thread to process packets
directly.
This commit is contained in:
Guus Sliepen 2009-09-15 22:59:01 +02:00
parent 802a50ffcd
commit b47c17bcde
4 changed files with 25 additions and 117 deletions
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126
src/mingw/device.c
View file

@ -34,7 +34,7 @@
#include "mingw/common.h"
int device_fd = 0;
int device_fd = -1;
static HANDLE device_handle = INVALID_HANDLE_VALUE;
char *device = NULL;
char *iface = NULL;
@ -45,63 +45,24 @@ static int device_total_out = 0;
extern char *myport;
static struct packetbuf {
uint8_t data[MTU];
length_t len;
} *bufs;
static int nbufs = 64;
static DWORD WINAPI tapreader(void *bla) {
int sock, err, status;
struct addrinfo *ai;
struct addrinfo hint = {
.ai_family = AF_UNSPEC,
.ai_socktype = SOCK_STREAM,
.ai_protocol = IPPROTO_TCP,
.ai_flags = 0,
};
unsigned char bufno = 0;
int status;
long len;
OVERLAPPED overlapped;
/* Open a socket to the parent process */
err = getaddrinfo(NULL, myport, &hint, &ai);
if(err || !ai) {
logger(LOG_ERR, _("System call `%s' failed: %s"), "getaddrinfo", gai_strerror(errno));
return -1;
}
sock = socket(ai->ai_family, SOCK_STREAM, IPPROTO_TCP);
if(sock < 0) {
logger(LOG_ERR, _("System call `%s' failed: %s"), "socket", strerror(errno));
freeaddrinfo(ai);
return -1;
}
if(connect(sock, ai->ai_addr, ai->ai_addrlen)) {
logger(LOG_ERR, _("System call `%s' failed: %s"), "connect", strerror(errno));
freeaddrinfo(ai);
return -1;
}
freeaddrinfo(ai);
vpn_packet_t packet;
logger(LOG_DEBUG, _("Tap reader running"));
/* Read from tap device and send to parent */
overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
for(;;) {
overlapped.Offset = 0;
overlapped.OffsetHigh = 0;
ResetEvent(overlapped.hEvent);
status = ReadFile(device_handle, bufs[bufno].data, MTU, &len, &overlapped);
status = ReadFile(device_handle, packet.data, MTU, &len, &overlapped);
if(!status) {
if(GetLastError() == ERROR_IO_PENDING) {
@ -115,11 +76,11 @@ static DWORD WINAPI tapreader(void *bla) {
}
}
bufs[bufno].len = len;
if(send(sock, &bufno, 1, 0) <= 0)
return -1;
if(++bufno >= nbufs)
bufno = 0;
EnterCriticalSection(&mutex);
packet.len = len;
packet.priority = 0;
route(myself, &packet);
LeaveCriticalSection(&mutex);
}
}
@ -240,44 +201,6 @@ bool setup_device(void)
overwrite_mac = 1;
}
/* Set up ringbuffer */
get_config_int(lookup_config(config_tree, "RingBufferSize"), &nbufs);
if(nbufs <= 1)
nbufs = 1;
else if(nbufs > 256)
nbufs = 256;
bufs = xmalloc_and_zero(nbufs * sizeof *bufs);
/* Create a listening socket */
err = getaddrinfo(NULL, myport, &hint, &ai);
if(err || !ai) {
logger(LOG_ERR, _("System call `%s' failed: %s"), "getaddrinfo", gai_strerror(errno));
return false;
}
sock = socket(ai->ai_family, SOCK_STREAM, IPPROTO_TCP);
if(sock < 0) {
logger(LOG_ERR, _("System call `%s' failed: %s"), "socket", strerror(errno));
return false;
}
if(bind(sock, ai->ai_addr, ai->ai_addrlen)) {
logger(LOG_ERR, _("System call `%s' failed: %s"), "bind", strerror(errno));
return false;
}
freeaddrinfo(ai);
if(listen(sock, 1)) {
logger(LOG_ERR, _("System call `%s' failed: %s"), "listen", strerror(errno));
return false;
}
/* Start the tap reader */
thread = CreateThread(NULL, 0, tapreader, NULL, 0, NULL);
@ -287,15 +210,6 @@ bool setup_device(void)
return false;
}
/* Wait for the tap reader to connect back to us */
if((device_fd = accept(sock, NULL, 0)) == -1) {
logger(LOG_ERR, _("System call `%s' failed: %s"), "accept", strerror(errno));
return false;
}
closesocket(sock);
/* Set media status for newer TAP-Win32 devices */
status = true;
@ -320,25 +234,7 @@ void close_device(void)
bool read_packet(vpn_packet_t *packet)
{
unsigned char bufno;
cp();
if((recv(device_fd, &bufno, 1, 0)) <= 0) {
logger(LOG_ERR, _("Error while reading from %s %s: %s"), device_info,
device, strerror(errno));
return false;
}
packet->len = bufs[bufno].len;
memcpy(packet->data, bufs[bufno].data, bufs[bufno].len);
device_total_in += packet->len;
ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
device_info);
return true;
return false;
}
bool write_packet(vpn_packet_t *packet)

11
src/net.c
View file

@ -149,7 +149,8 @@ static int build_fdset(fd_set *readset, fd_set *writeset)
max = listen_socket[i].udp;
}
FD_SET(device_fd, readset);
if(device_fd >= 0)
FD_SET(device_fd, readset);
if(device_fd > max)
max = device_fd;
@ -294,7 +295,7 @@ static void check_network_activity(fd_set * readset, fd_set * writeset)
cp();
/* check input from kernel */
if(FD_ISSET(device_fd, readset)) {
if(device_fd >= 0 && FD_ISSET(device_fd, readset)) {
if(read_packet(&packet)) {
packet.priority = 0;
route(myself, &packet);
@ -378,7 +379,13 @@ int main_loop(void)
maxfd = build_fdset(&readset, &writeset);
#ifdef HAVE_MINGW
LeaveCriticalSection(&mutex);
#endif
r = select(maxfd + 1, &readset, &writeset, NULL, &tv);
#ifdef HAVE_MINGW
EnterCriticalSection(&mutex);
#endif
if(r < 0) {
if(errno != EINTR && errno != EAGAIN) {

2
src/net.h
View file

@ -143,6 +143,8 @@ extern void send_mtu_probe(struct node_t *);
#ifndef HAVE_MINGW
#define closesocket(s) close(s)
#else
extern CRITICAL_SECTION mutex;
#endif
#endif /* __TINC_NET_H__ */

3
src/tincd.c
View file

@ -115,6 +115,7 @@ static struct option const long_options[] = {
#ifdef HAVE_MINGW
static struct WSAData wsa_state;
CRITICAL_SECTION mutex;
#endif
static void usage(bool status)
@ -568,6 +569,8 @@ int main(int argc, char **argv)
int main2(int argc, char **argv)
{
InitializeCriticalSection(&mutex);
EnterCriticalSection(&mutex);
#endif
if(!detach())