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Diffstat (limited to 'ntp.c')
| -rw-r--r-- | ntp.c | 85 |
1 files changed, 85 insertions, 0 deletions
@@ -0,0 +1,85 @@ +/* + * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that: (1) source code distributions + * retain the above copyright notice and this paragraph in its entirety, (2) + * distributions including binary code include the above copyright notice and + * this paragraph in its entirety in the documentation or other materials + * provided with the distribution, and (3) all advertising materials mentioning + * features or use of this software display the following acknowledgement: + * ``This product includes software developed by the University of California, + * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of + * the University nor the names of its contributors may be used to endorse + * or promote products derived from this software without specific prior + * written permission. + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. + * + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include "ntp.h" + +#include "extract.h" + +#define JAN_1970 INT64_T_CONSTANT(2208988800) /* 1970 - 1900 in seconds */ + +void +p_ntp_time(netdissect_options *ndo, + const struct l_fixedpt *lfp) +{ + uint32_t i; + uint32_t uf; + uint32_t f; + double ff; + + i = GET_BE_U_4(lfp->int_part); + uf = GET_BE_U_4(lfp->fraction); + ff = uf; + if (ff < 0.0) /* some compilers are buggy */ + ff += FMAXINT; + ff = ff / FMAXINT; /* shift radix point by 32 bits */ + f = (uint32_t)(ff * 1000000000.0); /* treat fraction as parts per billion */ + ND_PRINT("%u.%09u", i, f); + +#ifdef HAVE_STRFTIME + /* + * print the UTC time in human-readable format. + */ + if (i) { + int64_t seconds_64bit = (int64_t)i - JAN_1970; + time_t seconds; + struct tm *tm; + char time_buf[128]; + + seconds = (time_t)seconds_64bit; + if (seconds != seconds_64bit) { + /* + * It doesn't fit into a time_t, so we can't hand it + * to gmtime. + */ + ND_PRINT(" (unrepresentable)"); + } else { + tm = gmtime(&seconds); + if (tm == NULL) { + /* + * gmtime() can't handle it. + * (Yes, that might happen with some version of + * Microsoft's C library.) + */ + ND_PRINT(" (unrepresentable)"); + } else { + /* use ISO 8601 (RFC3339) format */ + strftime(time_buf, sizeof (time_buf), "%Y-%m-%dT%H:%M:%SZ", tm); + ND_PRINT(" (%s)", time_buf); + } + } + } +#endif +} |