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 33 void 34 p_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 #ifdef HAVE_STRFTIME 52 /* 53 * print the UTC time in human-readable format. 54 */ 55 if (i) { 56 int64_t seconds_64bit = (int64_t)i - JAN_1970; 57 time_t seconds; 58 struct tm *tm; 59 char time_buf[128]; 60 61 seconds = (time_t)seconds_64bit; 62 if (seconds != seconds_64bit) { 63 /* 64 * It doesn't fit into a time_t, so we can't hand it 65 * to gmtime. 66 */ 67 ND_PRINT(" (unrepresentable)"); 68 } else { 69 tm = gmtime(&seconds); 70 if (tm == NULL) { 71 /* 72 * gmtime() can't handle it. 73 * (Yes, that might happen with some version of 74 * Microsoft's C library.) 75 */ 76 ND_PRINT(" (unrepresentable)"); 77 } else { 78 /* use ISO 8601 (RFC3339) format */ 79 strftime(time_buf, sizeof (time_buf), "%Y-%m-%dT%H:%M:%SZ", tm); 80 ND_PRINT(" (%s)", time_buf); 81 } 82 } 83 } 84 #endif 85 } 86