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tcpdump/print-ntp.c
Guy Harris ff1df423b6 Use double rather than float. 
That means we can fit a 32-bit integer into a floating-point value
without losing precision.

Also, put in explicit casts when we convert a floating-point value to an
integral value, to suppress compiler warnings.
2015-09-14 15:12:28 -07:00

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/*
* 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.
*
* Format and print ntp packets.
* By Jeffrey Mogul/DECWRL
* loosely based on print-bootp.c
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <netdissect-stdinc.h>
#ifdef HAVE_STRFTIME
#include <time.h>
#endif
#include "netdissect.h"
#include "addrtoname.h"
#include "extract.h"
/*
* Based on ntp.h from the U of MD implementation
* This file is based on Version 2 of the NTP spec (RFC1119).
*/
/*
* Definitions for the masses
*/
#define JAN_1970 2208988800U /* 1970 - 1900 in seconds */
/*
* Structure definitions for NTP fixed point values
*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Integer Part |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Fraction Part |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Integer Part | Fraction Part |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
struct l_fixedpt {
uint32_t int_part;
uint32_t fraction;
};
struct s_fixedpt {
uint16_t int_part;
uint16_t fraction;
};
/* rfc2030
* 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |LI | VN |Mode | Stratum | Poll | Precision |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Root Delay |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Root Dispersion |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Reference Identifier |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | Reference Timestamp (64) |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | Originate Timestamp (64) |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | Receive Timestamp (64) |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | Transmit Timestamp (64) |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Key Identifier (optional) (32) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | |
* | Message Digest (optional) (128) |
* | |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
struct ntpdata {
u_char status; /* status of local clock and leap info */
u_char stratum; /* Stratum level */
u_char ppoll; /* poll value */
int precision:8;
struct s_fixedpt root_delay;
struct s_fixedpt root_dispersion;
uint32_t refid;
struct l_fixedpt ref_timestamp;
struct l_fixedpt org_timestamp;
struct l_fixedpt rec_timestamp;
struct l_fixedpt xmt_timestamp;
uint32_t key_id;
uint8_t message_digest[16];
};
/*
* Leap Second Codes (high order two bits)
*/
#define NO_WARNING 0x00 /* no warning */
#define PLUS_SEC 0x40 /* add a second (61 seconds) */
#define MINUS_SEC 0x80 /* minus a second (59 seconds) */
#define ALARM 0xc0 /* alarm condition (clock unsynchronized) */
/*
* Clock Status Bits that Encode Version
*/
#define NTPVERSION_1 0x08
#define VERSIONMASK 0x38
#define LEAPMASK 0xc0
#ifdef MODEMASK
#undef MODEMASK /* Solaris sucks */
#endif
#define MODEMASK 0x07
/*
* Code values
*/
#define MODE_UNSPEC 0 /* unspecified */
#define MODE_SYM_ACT 1 /* symmetric active */
#define MODE_SYM_PAS 2 /* symmetric passive */
#define MODE_CLIENT 3 /* client */
#define MODE_SERVER 4 /* server */
#define MODE_BROADCAST 5 /* broadcast */
#define MODE_RES1 6 /* reserved */
#define MODE_RES2 7 /* reserved */
/*
* Stratum Definitions
*/
#define UNSPECIFIED 0
#define PRIM_REF 1 /* radio clock */
#define INFO_QUERY 62 /* **** THIS implementation dependent **** */
#define INFO_REPLY 63 /* **** THIS implementation dependent **** */
static void p_sfix(netdissect_options *ndo, const struct s_fixedpt *);
static void p_ntp_time(netdissect_options *, const struct l_fixedpt *);
static void p_ntp_delta(netdissect_options *, const struct l_fixedpt *, const struct l_fixedpt *);
static const struct tok ntp_mode_values[] = {
{ MODE_UNSPEC, "unspecified" },
{ MODE_SYM_ACT, "symmetric active" },
{ MODE_SYM_PAS, "symmetric passive" },
{ MODE_CLIENT, "Client" },
{ MODE_SERVER, "Server" },
{ MODE_BROADCAST, "Broadcast" },
{ MODE_RES1, "Reserved" },
{ MODE_RES2, "Reserved" },
{ 0, NULL }
};
static const struct tok ntp_leapind_values[] = {
{ NO_WARNING, "" },
{ PLUS_SEC, "+1s" },
{ MINUS_SEC, "-1s" },
{ ALARM, "clock unsynchronized" },
{ 0, NULL }
};
static const struct tok ntp_stratum_values[] = {
{ UNSPECIFIED, "unspecified" },
{ PRIM_REF, "primary reference" },
{ 0, NULL }
};
/*
* Print ntp requests
*/
void
ntp_print(netdissect_options *ndo,
register const u_char *cp, u_int length)
{
register const struct ntpdata *bp;
int mode, version, leapind;
bp = (const struct ntpdata *)cp;
ND_TCHECK(bp->status);
version = (int)(bp->status & VERSIONMASK) >> 3;
ND_PRINT((ndo, "NTPv%d", version));
mode = bp->status & MODEMASK;
if (!ndo->ndo_vflag) {
ND_PRINT((ndo, ", %s, length %u",
tok2str(ntp_mode_values, "Unknown mode", mode),
length));
return;
}
ND_PRINT((ndo, ", length %u\n\t%s",
length,
tok2str(ntp_mode_values, "Unknown mode", mode)));
leapind = bp->status & LEAPMASK;
ND_PRINT((ndo, ", Leap indicator: %s (%u)",
tok2str(ntp_leapind_values, "Unknown", leapind),
leapind));
ND_TCHECK(bp->stratum);
ND_PRINT((ndo, ", Stratum %u (%s)",
bp->stratum,
tok2str(ntp_stratum_values, (bp->stratum >=2 && bp->stratum<=15) ? "secondary reference" : "reserved", bp->stratum)));
ND_TCHECK(bp->ppoll);
ND_PRINT((ndo, ", poll %u (%us)", bp->ppoll, 1 << bp->ppoll));
/* Can't ND_TCHECK bp->precision bitfield so bp->distance + 0 instead */
ND_TCHECK2(bp->root_delay, 0);
ND_PRINT((ndo, ", precision %d", bp->precision));
ND_TCHECK(bp->root_delay);
ND_PRINT((ndo, "\n\tRoot Delay: "));
p_sfix(ndo, &bp->root_delay);
ND_TCHECK(bp->root_dispersion);
ND_PRINT((ndo, ", Root dispersion: "));
p_sfix(ndo, &bp->root_dispersion);
ND_TCHECK(bp->refid);
ND_PRINT((ndo, ", Reference-ID: "));
/* Interpretation depends on stratum */
switch (bp->stratum) {
case UNSPECIFIED:
ND_PRINT((ndo, "(unspec)"));
break;
case PRIM_REF:
if (fn_printn(ndo, (const u_char *)&(bp->refid), 4, ndo->ndo_snapend))
goto trunc;
break;
case INFO_QUERY:
ND_PRINT((ndo, "%s INFO_QUERY", ipaddr_string(ndo, &(bp->refid))));
/* this doesn't have more content */
return;
case INFO_REPLY:
ND_PRINT((ndo, "%s INFO_REPLY", ipaddr_string(ndo, &(bp->refid))));
/* this is too complex to be worth printing */
return;
default:
ND_PRINT((ndo, "%s", ipaddr_string(ndo, &(bp->refid))));
break;
}
ND_TCHECK(bp->ref_timestamp);
ND_PRINT((ndo, "\n\t Reference Timestamp: "));
p_ntp_time(ndo, &(bp->ref_timestamp));
ND_TCHECK(bp->org_timestamp);
ND_PRINT((ndo, "\n\t Originator Timestamp: "));
p_ntp_time(ndo, &(bp->org_timestamp));
ND_TCHECK(bp->rec_timestamp);
ND_PRINT((ndo, "\n\t Receive Timestamp: "));
p_ntp_time(ndo, &(bp->rec_timestamp));
ND_TCHECK(bp->xmt_timestamp);
ND_PRINT((ndo, "\n\t Transmit Timestamp: "));
p_ntp_time(ndo, &(bp->xmt_timestamp));
ND_PRINT((ndo, "\n\t Originator - Receive Timestamp: "));
p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->rec_timestamp));
ND_PRINT((ndo, "\n\t Originator - Transmit Timestamp: "));
p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->xmt_timestamp));
if ( (sizeof(struct ntpdata) - length) == 16) { /* Optional: key-id */
ND_TCHECK(bp->key_id);
ND_PRINT((ndo, "\n\tKey id: %u", bp->key_id));
} else if ( (sizeof(struct ntpdata) - length) == 0) { /* Optional: key-id + authentication */
ND_TCHECK(bp->key_id);
ND_PRINT((ndo, "\n\tKey id: %u", bp->key_id));
ND_TCHECK2(bp->message_digest, sizeof (bp->message_digest));
ND_PRINT((ndo, "\n\tAuthentication: %08x%08x%08x%08x",
EXTRACT_32BITS(bp->message_digest),
EXTRACT_32BITS(bp->message_digest + 4),
EXTRACT_32BITS(bp->message_digest + 8),
EXTRACT_32BITS(bp->message_digest + 12)));
}
return;
trunc:
ND_PRINT((ndo, " [|ntp]"));
}
static void
p_sfix(netdissect_options *ndo,
register const struct s_fixedpt *sfp)
{
register int i;
register int f;
register double ff;
i = EXTRACT_16BITS(&sfp->int_part);
f = EXTRACT_16BITS(&sfp->fraction);
ff = f / 65536.0; /* shift radix point by 16 bits */
f = (int)(ff * 1000000.0); /* Treat fraction as parts per million */
ND_PRINT((ndo, "%d.%06d", i, f));
}
#define FMAXINT (4294967296.0) /* floating point rep. of MAXINT */
static void
p_ntp_time(netdissect_options *ndo,
register const struct l_fixedpt *lfp)
{
register int32_t i;
register uint32_t uf;
register uint32_t f;
register double ff;
i = EXTRACT_32BITS(&lfp->int_part);
uf = EXTRACT_32BITS(&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((ndo, "%u.%09d", i, f));
#ifdef HAVE_STRFTIME
/*
* print the time in human-readable format.
*/
if (i) {
time_t seconds = i - JAN_1970;
struct tm *tm;
char time_buf[128];
tm = localtime(&seconds);
strftime(time_buf, sizeof (time_buf), "%Y/%m/%d %H:%M:%S", tm);
ND_PRINT((ndo, " (%s)", time_buf));
}
#endif
}
/* Prints time difference between *lfp and *olfp */
static void
p_ntp_delta(netdissect_options *ndo,
register const struct l_fixedpt *olfp,
register const struct l_fixedpt *lfp)
{
register int32_t i;
register uint32_t u, uf;
register uint32_t ou, ouf;
register uint32_t f;
register double ff;
int signbit;
u = EXTRACT_32BITS(&lfp->int_part);
ou = EXTRACT_32BITS(&olfp->int_part);
uf = EXTRACT_32BITS(&lfp->fraction);
ouf = EXTRACT_32BITS(&olfp->fraction);
if (ou == 0 && ouf == 0) {
p_ntp_time(ndo, lfp);
return;
}
i = u - ou;
if (i > 0) { /* new is definitely greater than old */
signbit = 0;
f = uf - ouf;
if (ouf > uf) /* must borrow from high-order bits */
i -= 1;
} else if (i < 0) { /* new is definitely less than old */
signbit = 1;
f = ouf - uf;
if (uf > ouf) /* must carry into the high-order bits */
i += 1;
i = -i;
} else { /* int_part is zero */
if (uf > ouf) {
signbit = 0;
f = uf - ouf;
} else {
signbit = 1;
f = ouf - uf;
}
}
ff = f;
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((ndo, "%s%d.%09d", signbit ? "-" : "+", i, f));
}
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