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Diffstat (limited to '')
| -rw-r--r-- | src/ntp_server.c | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/src/ntp_server.c b/src/ntp_server.c new file mode 100644 index 000000000..3d8298f4a --- /dev/null +++ b/src/ntp_server.c @@ -0,0 +1,135 @@ +/* + * 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); +} |