1/*
2 * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code distributions
7 * retain the above copyright notice and this paragraph in its entirety, (2)
8 * distributions including binary code include the above copyright notice and
9 * this paragraph in its entirety in the documentation or other materials
10 * provided with the distribution, and (3) all advertising materials mentioning
11 * features or use of this software display the following acknowledgement:
12 * ``This product includes software developed by the University of California,
13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14 * the University nor the names of its contributors may be used to endorse
15 * or promote products derived from this software without specific prior
16 * written permission.
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20 *
21 */
22
23#ifdef HAVE_CONFIG_H
24#include <config.h>
25#endif
26
27#include "ntp.h"
28
29#include "extract.h"
30
31#define	JAN_1970	INT64_T_CONSTANT(2208988800)	/* 1970 - 1900 in seconds */
32
33void
34p_ntp_time(netdissect_options *ndo,
35	   const struct l_fixedpt *lfp)
36{
37	uint32_t i;
38	uint32_t uf;
39	uint32_t f;
40	double ff;
41
42	i = GET_BE_U_4(lfp->int_part);
43	uf = GET_BE_U_4(lfp->fraction);
44	ff = uf;
45	if (ff < 0.0)		/* some compilers are buggy */
46		ff += FMAXINT;
47	ff = ff / FMAXINT;			/* shift radix point by 32 bits */
48	f = (uint32_t)(ff * 1000000000.0);	/* treat fraction as parts per billion */
49	ND_PRINT("%u.%09u", i, f);
50
51	/*
52	 * print the UTC time in human-readable format.
53	 */
54	if (i) {
55	    int64_t seconds_64bit = (int64_t)i - JAN_1970;
56	    time_t seconds;
57	    char time_buf[128];
58	    const char *time_string;
59
60	    seconds = (time_t)seconds_64bit;
61	    if (seconds != seconds_64bit) {
62		/*
63		 * It doesn't fit into a time_t, so we can't hand it
64		 * to gmtime.
65		 */
66		time_string = "[Time is too large to fit into a time_t]";
67	    } else {
68		/* use ISO 8601 (RFC3339) format */
69		time_string = nd_format_time(time_buf, sizeof (time_buf),
70		  "%Y-%m-%dT%H:%M:%SZ", gmtime(&seconds));
71	    }
72	    ND_PRINT(" (%s)", time_string);
73	}
74}
75