xref: /original-bsd/bin/date/netdate.c (revision dd262573)
1 /*-
2  * Copyright (c) 1990 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * %sccs.include.redist.c%
6  */
7 
8 #ifndef lint
9 static char sccsid[] = "@(#)netdate.c	5.1 (Berkeley) 12/04/90";
10 #endif /* not lint */
11 
12 #include <sys/param.h>
13 #include <sys/time.h>
14 #include <sys/socket.h>
15 #include <sys/errno.h>
16 #include <netinet/in.h>
17 #include <netdb.h>
18 #define TSPTYPES
19 #include <protocols/timed.h>
20 #include <stdio.h>
21 
22 #define	WAITACK		2	/* seconds */
23 #define	WAITDATEACK	5	/* seconds */
24 
25 extern int retval;
26 
27 /*
28  * Set the date in the machines controlled by timedaemons by communicating the
29  * new date to the local timedaemon.  If the timedaemon is in the master state,
30  * it performs the correction on all slaves.  If it is in the slave state, it
31  * notifies the master that a correction is needed.
32  * Returns 0 on success.  Returns > 0 on failure, setting retval to 2;
33  */
34 netsettime(tval)
35 	time_t tval;
36 {
37 	struct timeval tout;
38 	struct servent *sp;
39 	struct tsp msg;
40 	struct sockaddr_in sin, dest, from;
41 	fd_set ready;
42 	long waittime;
43 	int s, length, port, timed_ack, found, err;
44 	char hostname[MAXHOSTNAMELEN];
45 
46 	if ((sp = getservbyname("timed", "udp")) == NULL) {
47 		(void)fprintf(stderr, "date: udp/timed: unknown service.n");
48 		return (retval = 2);
49 	}
50 
51 	dest.sin_port = sp->s_port;
52 	dest.sin_family = AF_INET;
53 	dest.sin_addr.s_addr = htonl((u_long)INADDR_ANY);
54 	s = socket(AF_INET, SOCK_DGRAM, 0);
55 	if (s < 0) {
56 		if (errno != EPROTONOSUPPORT)
57 			perror("date: timed");
58 		return(retval = 2);
59 	}
60 
61 	bzero((char *)&sin, sizeof(sin));
62 	sin.sin_family = AF_INET;
63 	for (port = IPPORT_RESERVED - 1; port > IPPORT_RESERVED / 2; port--) {
64 		sin.sin_port = htons((u_short)port);
65 		if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
66 			break;
67 		if (errno == EADDRINUSE)
68 			continue;
69 		if (errno != EADDRNOTAVAIL)
70 			perror("date: bind");
71 		goto bad;
72 	}
73 	if (port == IPPORT_RESERVED / 2) {
74 		(void)fprintf(stderr, "date: all ports in use.\n");
75 		goto bad;
76 	}
77 	msg.tsp_type = TSP_SETDATE;
78 	msg.tsp_vers = TSPVERSION;
79 	if (gethostname(hostname, sizeof(hostname))) {
80 		perror("date: gethostname");
81 		goto bad;
82 	}
83 	(void)strncpy(msg.tsp_name, hostname, sizeof(hostname));
84 	msg.tsp_seq = htons((u_short)0);
85 	msg.tsp_time.tv_sec = htonl((u_long)tval);
86 	msg.tsp_time.tv_usec = htonl((u_long)0);
87 	length = sizeof(struct sockaddr_in);
88 	if (connect(s, &dest, length) < 0) {
89 		perror("date: connect");
90 		goto bad;
91 	}
92 	if (send(s, (char *)&msg, sizeof(struct tsp), 0) < 0) {
93 		if (errno != ECONNREFUSED)
94 			perror("date: send");
95 		goto bad;
96 	}
97 
98 	timed_ack = -1;
99 	waittime = WAITACK;
100 loop:
101 	tout.tv_sec = waittime;
102 	tout.tv_usec = 0;
103 
104 	FD_ZERO(&ready);
105 	FD_SET(s, &ready);
106 	found = select(FD_SETSIZE, &ready, (fd_set *)0, (fd_set *)0, &tout);
107 
108 	length = sizeof(err);
109 	if (!getsockopt(s, SOL_SOCKET, SO_ERROR, (char *)&err, &length)
110 	    && err) {
111 		if (err != ECONNREFUSED)
112 			perror("date: send (delayed error)");
113 		goto bad;
114 	}
115 
116 	if (found > 0 && FD_ISSET(s, &ready)) {
117 		length = sizeof(struct sockaddr_in);
118 		if (recvfrom(s, (char *)&msg, sizeof(struct tsp), 0, &from,
119 		    &length) < 0) {
120 			if (errno != ECONNREFUSED)
121 				perror("date: recvfrom");
122 			goto bad;
123 		}
124 		msg.tsp_seq = ntohs(msg.tsp_seq);
125 		msg.tsp_time.tv_sec = ntohl(msg.tsp_time.tv_sec);
126 		msg.tsp_time.tv_usec = ntohl(msg.tsp_time.tv_usec);
127 		switch (msg.tsp_type) {
128 		case TSP_ACK:
129 			timed_ack = TSP_ACK;
130 			waittime = WAITDATEACK;
131 			goto loop;
132 		case TSP_DATEACK:
133 			(void)close(s);
134 			return (0);
135 		default:
136 			(void)fprintf(stderr,
137 			    "date: wrong ack received from timed: %s.\n",
138 			    tsptype[msg.tsp_type]);
139 			timed_ack = -1;
140 			break;
141 		}
142 	}
143 	if (timed_ack == -1)
144 		(void)fprintf(stderr,
145 		    "date: can't reach time daemon, time set locally.\n");
146 
147 bad:
148 	(void)close(s);
149 	return(retval = 2);
150 }
151