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 #include <config.h> 24 25 #include "ntp.h" 26 27 #include "extract.h" 28 29 #define JAN_1970 INT64_T_CONSTANT(2208988800) /* 1970 - 1900 in seconds */ 30 31 void 32 p_ntp_time(netdissect_options *ndo, 33 const struct l_fixedpt *lfp) 34 { 35 uint32_t i; 36 uint32_t uf; 37 uint32_t f; 38 double ff; 39 40 i = GET_BE_U_4(lfp->int_part); 41 uf = GET_BE_U_4(lfp->fraction); 42 ff = uf; 43 if (ff < 0.0) /* some compilers are buggy */ 44 ff += FMAXINT; 45 ff = ff / FMAXINT; /* shift radix point by 32 bits */ 46 f = (uint32_t)(ff * 1000000000.0); /* treat fraction as parts per billion */ 47 ND_PRINT("%u.%09u", i, f); 48 49 /* 50 * print the UTC time in human-readable format. 51 */ 52 if (i) { 53 int64_t seconds_64bit = (int64_t)i - JAN_1970; 54 time_t seconds; 55 char time_buf[128]; 56 const char *time_string; 57 58 seconds = (time_t)seconds_64bit; 59 if (seconds != seconds_64bit) { 60 /* 61 * It doesn't fit into a time_t, so we can't hand it 62 * to gmtime. 63 */ 64 time_string = "[Time is too large to fit into a time_t]"; 65 } else { 66 /* use ISO 8601 (RFC3339) format */ 67 time_string = nd_format_time(time_buf, sizeof (time_buf), 68 "%Y-%m-%dT%H:%M:%SZ", gmtime(&seconds)); 69 } 70 ND_PRINT(" (%s)", time_string); 71 } 72 } 73