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-rw-r--r--src/ntp_server.c132
1 files changed, 132 insertions, 0 deletions
diff --git a/src/ntp_server.c b/src/ntp_server.c
new file mode 100644
index 000000000..c33c0a933
--- /dev/null
+++ b/src/ntp_server.c
@@ -0,0 +1,132 @@
+/*
+ * 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 "udp_server.h"
+
+#include <glib.h>
+#include <assert.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/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(&current_time,NULL);
+ fill_time_buffer_with_time(buffer, &current_time);
+}
+
+static void
+ntp_server_datagram(int fd, const void *data, size_t num_bytes,
+ const struct sockaddr *source_address,
+ size_t source_address_length, G_GNUC_UNUSED void *ctx)
+{
+ unsigned char buf[32];
+ int iter;
+
+ if (num_bytes > sizeof(buf))
+ num_bytes = sizeof(buf);
+ memcpy(buf, data, num_bytes);
+
+ 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);
+
+ sendto(fd, (void *)buf, num_bytes, 0,
+ source_address, source_address_length);
+}
+
+static const struct udp_server_handler ntp_server_handler = {
+ .datagram = ntp_server_datagram,
+};
+
+void
+ntp_server_init(struct ntp_server *ntp)
+{
+ ntp->port = 6002;
+ ntp->udp = NULL;
+}
+
+bool
+ntp_server_open(struct ntp_server *ntp, GError **error_r)
+{
+ assert(ntp->udp == NULL);
+
+ ntp->udp = udp_server_new(ntp->port, &ntp_server_handler, ntp,
+ error_r);
+ return ntp->udp != NULL;
+}
+
+void
+ntp_server_close(struct ntp_server *ntp)
+{
+ if (ntp->udp != NULL) {
+ udp_server_free(ntp->udp);
+ ntp->udp = NULL;
+ }
+}