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/*
* Copyright (C) 2003-2011 The Music Player Daemon Project
* http://www.musicpd.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
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "ntp_server.h"
#include <glib.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <sys/time.h>
#ifdef WIN32
#define WINVER 0x0501
#include <ws2tcpip.h>
#include <winsock.h>
#else
#include <sys/select.h>
#include <sys/socket.h>
#endif
/*
* Calculate the current NTP time, store it in the buffer.
*/
static void
fill_int(unsigned char *buffer, uint32_t value)
{
uint32_t be = GINT32_TO_BE(value);
memcpy(buffer, &be, sizeof(be));
}
/*
* Store time in the NTP format in the buffer
*/
static void
fill_time_buffer_with_time(unsigned char *buffer, struct timeval *tout)
{
unsigned long secs_to_baseline = 964697997;
double fraction;
unsigned long long_fraction;
unsigned long secs;
fraction = ((double) tout->tv_usec) / 1000000.0;
long_fraction = (unsigned long) (fraction * 256.0 * 256.0 * 256.0 * 256.0);
secs = secs_to_baseline + tout->tv_sec;
fill_int(buffer, secs);
fill_int(buffer + 4, long_fraction);
}
/*
* Calculate the current NTP time, store it in the buffer.
*/
static void
fill_time_buffer(unsigned char *buffer)
{
struct timeval current_time;
gettimeofday(¤t_time,NULL);
fill_time_buffer_with_time(buffer, ¤t_time);
}
bool
ntp_server_handle(struct ntp_server *ntp)
{
unsigned char buf[32];
struct sockaddr addr;
int iter;
unsigned int addr_len = sizeof(addr);
int num_bytes = recvfrom(ntp->fd, buf, sizeof(buf), 0, &addr, &addr_len);
if (num_bytes == 0) {
return false;
}
fill_time_buffer(buf + 16);
// set to response
buf[1] = 0xd3;
// copy request
for (iter = 0; iter < 8; iter++) {
buf[8 + iter] = buf[24 + iter];
}
fill_time_buffer(buf + 24);
num_bytes = sendto(ntp->fd, buf, num_bytes, 0, &addr, addr_len);
return num_bytes == sizeof(buf);
}
bool
ntp_server_check(struct ntp_server *ntp, struct timeval *tout)
{
fd_set rdfds;
int fdmax = 0;
FD_ZERO(&rdfds);
FD_SET(ntp->fd, &rdfds);
fdmax = ntp->fd;
select(fdmax + 1, &rdfds,NULL, NULL, tout);
if (FD_ISSET(ntp->fd, &rdfds)) {
if (!ntp_server_handle(ntp)) {
g_debug("unable to send timing response\n");
return false;
}
}
return true;
}
void
ntp_server_init(struct ntp_server *ntp)
{
ntp->port = 6002;
ntp->fd = -1;
}
void
ntp_server_close(struct ntp_server *ntp)
{
if (ntp->fd >= 0)
close(ntp->fd);
}
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