xref: /openbsd/usr.sbin/tcpdump/print-ntp.c (revision e5dd7070)
1 /*	$OpenBSD: print-ntp.c,v 1.19 2020/01/24 22:46:37 procter Exp $	*/
2 
3 /*
4  * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that: (1) source code distributions
9  * retain the above copyright notice and this paragraph in its entirety, (2)
10  * distributions including binary code include the above copyright notice and
11  * this paragraph in its entirety in the documentation or other materials
12  * provided with the distribution, and (3) all advertising materials mentioning
13  * features or use of this software display the following acknowledgement:
14  * ``This product includes software developed by the University of California,
15  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
16  * the University nor the names of its contributors may be used to endorse
17  * or promote products derived from this software without specific prior
18  * written permission.
19  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
20  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
21  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
22  *
23  * Format and print ntp packets.
24  *	By Jeffrey Mogul/DECWRL
25  *	loosely based on print-bootp.c
26  */
27 
28 #include <sys/time.h>
29 #include <sys/socket.h>
30 
31 struct mbuf;
32 struct rtentry;
33 #include <net/if.h>
34 
35 #include <netinet/in.h>
36 #include <netinet/if_ether.h>
37 
38 #include <ctype.h>
39 #include <stdio.h>
40 #include <string.h>
41 
42 #include "interface.h"
43 #include "addrtoname.h"
44 #ifdef MODEMASK
45 #undef MODEMASK					/* Solaris sucks */
46 #endif
47 #include "ntp.h"
48 
49 static void p_sfix(const struct s_fixedpt *);
50 static void p_ntp_time(const struct l_fixedpt *);
51 static void p_ntp_delta(const struct l_fixedpt *, const struct l_fixedpt *);
52 
53 /*
54  * Print ntp requests
55  */
56 void
57 ntp_print(const u_char *cp, u_int length)
58 {
59 	const struct ntpdata *bp;
60 	int mode, version, leapind;
61 
62 	bp = (struct ntpdata *)cp;
63 	/* Note funny sized packets */
64 	if (length != sizeof(struct ntpdata))
65 		printf(" [len=%d]", length);
66 
67 	TCHECK(bp->status);
68 
69 	version = (int)(bp->status & VERSIONMASK) >> 3;
70 	printf("v%d", version);
71 
72 	leapind = bp->status & LEAPMASK;
73 	switch (leapind) {
74 
75 	case NO_WARNING:
76 		break;
77 
78 	case ALARM:
79 		printf(" alarm");
80 		break;
81 
82 	case PLUS_SEC:
83 		printf(" +1s");
84 		break;
85 
86 	case MINUS_SEC:
87 		printf(" -1s");
88 		break;
89 	}
90 
91 	mode = bp->status & MODEMASK;
92 	switch (mode) {
93 
94 	case MODE_UNSPEC:	/* unspecified */
95 		printf(" unspec");
96 		break;
97 
98 	case MODE_SYM_ACT:	/* symmetric active */
99 		printf(" sym_act");
100 		break;
101 
102 	case MODE_SYM_PAS:	/* symmetric passive */
103 		printf(" sym_pas");
104 		break;
105 
106 	case MODE_CLIENT:	/* client */
107 		printf(" client");
108 		break;
109 
110 	case MODE_SERVER:	/* server */
111 		printf(" server");
112 		break;
113 
114 	case MODE_BROADCAST:	/* broadcast */
115 		printf(" bcast");
116 		break;
117 
118 	case MODE_RES1:		/* reserved */
119 		printf(" res1");
120 		break;
121 
122 	case MODE_RES2:		/* reserved */
123 		printf(" res2");
124 		break;
125 
126 	}
127 
128 	TCHECK(bp->stratum);
129 	printf(" strat %d", bp->stratum);
130 
131 	TCHECK(bp->ppoll);
132 	printf(" poll %d", bp->ppoll);
133 
134 	/* Can't TCHECK bp->precision bitfield so bp->distance + 0 instead */
135 	TCHECK2(bp->distance, 0);
136 	printf(" prec %d", bp->precision);
137 
138 	if (!vflag)
139 		return;
140 
141 	TCHECK(bp->distance);
142 	printf(" dist ");
143 	p_sfix(&bp->distance);
144 
145 	TCHECK(bp->dispersion);
146 	printf(" disp ");
147 	p_sfix(&bp->dispersion);
148 
149 	TCHECK(bp->refid);
150 	printf(" ref ");
151 	/* Interpretation depends on stratum */
152 	switch (bp->stratum) {
153 
154 	case UNSPECIFIED:
155 		printf("(unspec)");
156 		break;
157 
158 	case PRIM_REF:
159 		fn_printn((u_char *)&bp->refid, sizeof(bp->refid), NULL);
160 		break;
161 
162 	case INFO_QUERY:
163 		printf("%s INFO_QUERY", ipaddr_string(&(bp->refid)));
164 		/* this doesn't have more content */
165 		return;
166 
167 	case INFO_REPLY:
168 		printf("%s INFO_REPLY", ipaddr_string(&(bp->refid)));
169 		/* this is too complex to be worth printing */
170 		return;
171 
172 	default:
173 		printf("%s", ipaddr_string(&(bp->refid)));
174 		break;
175 	}
176 
177 	TCHECK(bp->reftime);
178 	putchar('@');
179 	p_ntp_time(&(bp->reftime));
180 
181 	TCHECK(bp->org);
182 	printf(" orig ");
183 	p_ntp_time(&(bp->org));
184 
185 	TCHECK(bp->rec);
186 	printf(" rec ");
187 	p_ntp_delta(&(bp->org), &(bp->rec));
188 
189 	TCHECK(bp->xmt);
190 	printf(" xmt ");
191 	p_ntp_delta(&(bp->org), &(bp->xmt));
192 
193 	return;
194 
195 trunc:
196 	printf(" [|ntp]");
197 }
198 
199 static void
200 p_sfix(const struct s_fixedpt *sfp)
201 {
202 	int i;
203 	int f;
204 	float ff;
205 
206 	i = ntohs(sfp->int_part);
207 	f = ntohs(sfp->fraction);
208 	ff = f / 65536.0;	/* shift radix point by 16 bits */
209 	f = ff * 1000000.0;	/* Treat fraction as parts per million */
210 	printf("%d.%06d", i, f);
211 }
212 
213 #define	FMAXINT	(4294967296.0)	/* floating point rep. of MAXINT */
214 
215 static void
216 p_ntp_time(const struct l_fixedpt *lfp)
217 {
218 	int32_t i;
219 	u_int32_t uf;
220 	u_int32_t f;
221 	float ff;
222 
223 	i = ntohl(lfp->int_part);
224 	uf = ntohl(lfp->fraction);
225 	ff = uf;
226 	if (ff < 0.0)		/* some compilers are buggy */
227 		ff += FMAXINT;
228 	ff = ff / FMAXINT;	/* shift radix point by 32 bits */
229 	f = ff * 1000000000.0;	/* treat fraction as parts per billion */
230 	printf("%u.%09d", i, f);
231 }
232 
233 /* Prints time difference between *lfp and *olfp */
234 static void
235 p_ntp_delta(const struct l_fixedpt *olfp, const struct l_fixedpt *lfp)
236 {
237 	int32_t i;
238 	u_int32_t uf;
239 	u_int32_t ouf;
240 	u_int32_t f;
241 	float ff;
242 	int signbit;
243 
244 	i = ntohl(lfp->int_part) - ntohl(olfp->int_part);
245 
246 	uf = ntohl(lfp->fraction);
247 	ouf = ntohl(olfp->fraction);
248 
249 	if (i > 0) {		/* new is definitely greater than old */
250 		signbit = 0;
251 		f = uf - ouf;
252 		if (ouf > uf)	/* must borrow from high-order bits */
253 			i -= 1;
254 	} else if (i < 0) {	/* new is definitely less than old */
255 		signbit = 1;
256 		f = ouf - uf;
257 		if (uf > ouf)	/* must carry into the high-order bits */
258 			i += 1;
259 		i = -i;
260 	} else {		/* int_part is zero */
261 		if (uf > ouf) {
262 			signbit = 0;
263 			f = uf - ouf;
264 		} else {
265 			signbit = 1;
266 			f = ouf - uf;
267 		}
268 	}
269 
270 	ff = f;
271 	if (ff < 0.0)		/* some compilers are buggy */
272 		ff += FMAXINT;
273 	ff = ff / FMAXINT;	/* shift radix point by 32 bits */
274 	f = ff * 1000000000.0;	/* treat fraction as parts per billion */
275 	if (signbit)
276 		putchar('-');
277 	else
278 		putchar('+');
279 	printf("%d.%09d", i, f);
280 }
281