/*      $OpenBSD: print-ntp.c,v 1.20 2021/12/01 18:28:46 deraadt Exp $  */

/*
 * 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
 */

#include <sys/time.h>
#include <sys/socket.h>

#include <net/if.h>

#include <netinet/in.h>
#include <netinet/if_ether.h>

#include <ctype.h>
#include <stdio.h>
#include <string.h>

#include "interface.h"
#include "addrtoname.h"
#ifdef MODEMASK
#undef MODEMASK                                 /* Solaris sucks */
#endif
#include "ntp.h"

static void p_sfix(const struct s_fixedpt *);
static void p_ntp_time(const struct l_fixedpt *);
static void p_ntp_delta(const struct l_fixedpt *, const struct l_fixedpt *);

/*
 * Print ntp requests
 */
void
ntp_print(const u_char *cp, u_int length)
{
        const struct ntpdata *bp;
        int mode, version, leapind;

        bp = (struct ntpdata *)cp;
        /* Note funny sized packets */
        if (length != sizeof(struct ntpdata))
                printf(" [len=%d]", length);

        TCHECK(bp->status);

        version = (int)(bp->status & VERSIONMASK) >> 3;
        printf("v%d", version);

        leapind = bp->status & LEAPMASK;
        switch (leapind) {

        case NO_WARNING:
                break;

        case ALARM:
                printf(" alarm");
                break;

        case PLUS_SEC:
                printf(" +1s");
                break;

        case MINUS_SEC:
                printf(" -1s");
                break;
        }

        mode = bp->status & MODEMASK;
        switch (mode) {

        case MODE_UNSPEC:       /* unspecified */
                printf(" unspec");
                break;

        case MODE_SYM_ACT:      /* symmetric active */
                printf(" sym_act");
                break;

        case MODE_SYM_PAS:      /* symmetric passive */
                printf(" sym_pas");
                break;

        case MODE_CLIENT:       /* client */
                printf(" client");
                break;

        case MODE_SERVER:       /* server */
                printf(" server");
                break;

        case MODE_BROADCAST:    /* broadcast */
                printf(" bcast");
                break;

        case MODE_RES1:         /* reserved */
                printf(" res1");
                break;

        case MODE_RES2:         /* reserved */
                printf(" res2");
                break;

        }

        TCHECK(bp->stratum);
        printf(" strat %d", bp->stratum);

        TCHECK(bp->ppoll);
        printf(" poll %d", bp->ppoll);

        /* Can't TCHECK bp->precision bitfield so bp->distance + 0 instead */
        TCHECK2(bp->distance, 0);
        printf(" prec %d", bp->precision);

        if (!vflag)
                return;

        TCHECK(bp->distance);
        printf(" dist ");
        p_sfix(&bp->distance);

        TCHECK(bp->dispersion);
        printf(" disp ");
        p_sfix(&bp->dispersion);

        TCHECK(bp->refid);
        printf(" ref ");
        /* Interpretation depends on stratum */
        switch (bp->stratum) {

        case UNSPECIFIED:
                printf("(unspec)");
                break;

        case PRIM_REF:
                fn_printn((u_char *)&bp->refid, sizeof(bp->refid), NULL);
                break;

        case INFO_QUERY:
                printf("%s INFO_QUERY", ipaddr_string(&(bp->refid)));
                /* this doesn't have more content */
                return;

        case INFO_REPLY:
                printf("%s INFO_REPLY", ipaddr_string(&(bp->refid)));
                /* this is too complex to be worth printing */
                return;

        default:
                printf("%s", ipaddr_string(&(bp->refid)));
                break;
        }

        TCHECK(bp->reftime);
        putchar('@');
        p_ntp_time(&(bp->reftime));

        TCHECK(bp->org);
        printf(" orig ");
        p_ntp_time(&(bp->org));

        TCHECK(bp->rec);
        printf(" rec ");
        p_ntp_delta(&(bp->org), &(bp->rec));

        TCHECK(bp->xmt);
        printf(" xmt ");
        p_ntp_delta(&(bp->org), &(bp->xmt));

        return;

trunc:
        printf(" [|ntp]");
}

static void
p_sfix(const struct s_fixedpt *sfp)
{
        int i;
        int f;
        float ff;

        i = ntohs(sfp->int_part);
        f = ntohs(sfp->fraction);
        ff = f / 65536.0;       /* shift radix point by 16 bits */
        f = ff * 1000000.0;     /* Treat fraction as parts per million */
        printf("%d.%06d", i, f);
}

#define FMAXINT (4294967296.0)  /* floating point rep. of MAXINT */

static void
p_ntp_time(const struct l_fixedpt *lfp)
{
        int32_t i;
        u_int32_t uf;
        u_int32_t f;
        float ff;

        i = ntohl(lfp->int_part);
        uf = ntohl(lfp->fraction);
        ff = uf;
        if (ff < 0.0)           /* some compilers are buggy */
                ff += FMAXINT;
        ff = ff / FMAXINT;      /* shift radix point by 32 bits */
        f = ff * 1000000000.0;  /* treat fraction as parts per billion */
        printf("%u.%09d", i, f);
}

/* Prints time difference between *lfp and *olfp */
static void
p_ntp_delta(const struct l_fixedpt *olfp, const struct l_fixedpt *lfp)
{
        int32_t i;
        u_int32_t uf;
        u_int32_t ouf;
        u_int32_t f;
        float ff;
        int signbit;

        i = ntohl(lfp->int_part) - ntohl(olfp->int_part);

        uf = ntohl(lfp->fraction);
        ouf = ntohl(olfp->fraction);

        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 = ff * 1000000000.0;  /* treat fraction as parts per billion */
        if (signbit)
                putchar('-');
        else
                putchar('+');
        printf("%d.%09d", i, f);
}