/*	$OpenBSD: client.c,v 1.1 2004/06/17 19:17:48 henning Exp $ */

/*
 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
 * Copyright (c) 2004 Alexander Guy <alexander.guy@andern.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/param.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include "ntpd.h"

int
client_peer_init(struct ntp_peer *p)
{
	struct sockaddr_in	*sa_in;
	struct sockaddr_in6	*sa_in6;

	if ((p->query = calloc(1, sizeof(struct ntp_msg))) == NULL)
		fatal("client_query calloc");

	switch (p->ss.ss_family) {
	case AF_INET:
		sa_in = (struct sockaddr_in *)&p->ss;
		if (ntohs(sa_in->sin_port) == 0)
			sa_in->sin_port = htons(123);
		break;
	case AF_INET6:
		sa_in6 = (struct sockaddr_in6 *)&p->ss;
		if (ntohs(sa_in6->sin6_port) == 0)
			sa_in6->sin6_port = htons(123);
		break;
	default:
		fatal("king bula sez: wrong AF in client_peer_init");
		/* not reached */
	}

	if ((p->query->fd = socket(p->ss.ss_family, SOCK_DGRAM, 0)) == -1)
		fatal("client_query socket");

	p->query->msg.status = MODE_CLIENT | (NTP_VERSION << 3);
	p->state = STATE_NONE;
	p->next = time(NULL);

	return (0);
}

int
client_query(struct ntp_peer *p)
{
	/*
	 * Send out a random 64-bit number as our transmit time.  The NTP
	 * server will copy said number into the originate field on the
	 * response that it sends us.  This is totally legal per the SNTP spec.
	 *
	 * The impact of this is two fold: we no longer send out the current
	 * system time for the world to see (which may aid an attacker), and
	 * it gives us a (not very secure) way of knowing that we're not
	 * getting spoofed by an attacker that can't capture our traffic
	 * but can spoof packets from the NTP server we're communicating with.
	 *
	 * Save the real transmit timestamp locally.
	 */

	p->query->msg.xmttime.int_part = arc4random();
	p->query->msg.xmttime.fraction = arc4random();
	get_ts(&p->query->xmttime);

	ntp_sendmsg(p->query->fd, (struct sockaddr *)&p->ss, &p->query->msg,
	    NTP_MSGSIZE_NOAUTH, 0);
	p->state = STATE_QUERY_SENT;
	p->next = 0;
	p->deadline = time(NULL) + MAX_QUERYTIME;

	return (0);
}

int
client_dispatch(struct ntp_peer *p)
{
	struct sockaddr_storage	 fsa;
	socklen_t		 fsa_len;
	char			 buf[NTP_MSGSIZE];
	ssize_t			 size;
	struct ntp_msg		 msg;
	struct l_fixedpt	 rtt, t;

	fsa_len = sizeof(fsa);
	if ((size = recvfrom(p->query->fd, &buf, sizeof(buf), 0,
	    (struct sockaddr *)&fsa, &fsa_len)) == -1)
		fatal("recvfrom");

	ntp_getmsg(buf, size, &msg);

	if (msg.orgtime.int_part != p->query->msg.xmttime.int_part ||
	    msg.orgtime.fraction != p->query->msg.xmttime.fraction) {
		log_warn("received packet without correct cookie, discarding");
		return (0);
	}

log_debug("reply received");

	/* XXX parse */
	get_ts(&t);
	rtt.int_part = (t.int_part - p->query->xmttime.int_part) -
	    (msg.rectime.int_part - msg.xmttime.int_part);

	p->state = STATE_REPLY_RECEIVED;
	p->next = time(NULL) + QUERY_INTERVAL;
	p->deadline = 0;

	return (0);
}