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freebsd-skq/usr.sbin/xntpd/ntpdate/ntpdate.c
Garrett Wollman daa35edbd0 xntp 3.4e from Dave Mills @ UDel
1994-09-29 23:04:24 +00:00

1587 lines
34 KiB
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/*
* ntpdate - set the time of day by polling one or more NTP servers
*/
#include <stdio.h>
#include <signal.h>
#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/signal.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/resource.h>
#ifdef __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif
#if defined(SYS_HPUX)
#include <utmp.h>
#endif
#ifdef SYS_LINUX
#include <sys/timex.h>
#endif
#ifndef SYSLOG_FILE
#define SYSLOG_FILE /* we want to go through the syslog/printf/file code */
#endif
#include "ntp_select.h"
#include "ntp_fp.h"
#include "ntp.h"
#include "ntp_io.h"
#include "ntp_unixtime.h"
#include "ntpdate.h"
#include "ntp_string.h"
#include "ntp_stdlib.h"
#include "ntp_syslog.h"
/*
* Scheduling priority we run at
*/
#define NTPDATE_PRIO (-12)
/*
* Compatibility stuff for Version 2
*/
#define NTP_MAXSKW 0x28f /* 0.01 sec in fp format */
#define NTP_MINDIST 0x51f /* 0.02 sec in fp format */
#define PEER_MAXDISP (64*FP_SECOND) /* maximum dispersion (fp 64) */
#define NTP_INFIN 15 /* max stratum, infinity a la Bellman-Ford */
#define NTP_MAXWGT (8*FP_SECOND) /* maximum select weight 8 seconds */
#define NTP_MAXLIST 5 /* maximum select list size */
#define PEER_SHIFT 8 /* 8 suitable for crystal time base */
/*
* Debugging flag
*/
int debug = 0;
/*
* File descriptor masks etc. for call to select
*/
int fd;
fd_set fdmask;
/*
* Initializing flag. All async routines watch this and only do their
* thing when it is clear.
*/
int initializing = 1;
/*
* Alarm flag. Set when an alarm occurs
*/
int alarm_flag = 0;
/*
* Simple query flag.
*/
int simple_query = 0;
/*
* Program name.
*/
char *progname;
/*
* Systemwide parameters and flags
*/
int sys_samples = DEFSAMPLES; /* number of samples/server */
u_long sys_timeout = DEFTIMEOUT; /* timeout time, in TIMER_HZ units */
struct server **sys_servers; /* the server list */
int sys_numservers = 0; /* number of servers to poll */
int sys_maxservers = 0; /* max number of servers to deal with */
int sys_authenticate = 0; /* true when authenticating */
u_long sys_authkey = 0; /* set to authentication key in use */
u_long sys_authdelay = 0; /* authentication delay */
int sys_version = NTP_VERSION; /* version to poll with */
/*
* The current internal time
*/
u_long current_time = 0;
/*
* Counter for keeping track of completed servers
*/
int complete_servers = 0;
/*
* File of encryption keys
*/
#ifndef KEYFILE
#define KEYFILE "/etc/ntp.keys"
#endif /* KEYFILE */
char *key_file = KEYFILE;
/*
* Miscellaneous flags
*/
extern int syslogit;
int verbose = 0;
int always_step = 0;
extern int errno;
static void transmit P((struct server *));
static void receive P((struct recvbuf *));
static void server_data P((struct server *, s_fp, l_fp *, u_fp));
static void clock_filter P((struct server *));
static struct server *clock_select P((void));
static int clock_adjust P((void));
static void addserver P((char *));
static struct server *findserver P((struct sockaddr_in *));
static void timer P((void));
static void init_alarm P((void));
static RETSIGTYPE alarming P((int));
static void init_io P((void));
static struct recvbuf *getrecvbufs P((void));
static void freerecvbuf P((struct recvbuf *));
static void sendpkt P((struct sockaddr_in *, struct pkt *, int));
static void input_handler P((void));
static int l_adj_systime P((l_fp *));
static int l_step_systime P((l_fp *));
static int getnetnum P((char *, u_long *));
static void printserver P((struct server *, FILE *));
/*
* Main program. Initialize us and loop waiting for I/O and/or
* timer expiries.
*/
void
main(argc, argv)
int argc;
char *argv[];
{
int was_alarmed;
struct recvbuf *rbuflist;
struct recvbuf *rbuf;
l_fp tmp;
int errflg;
int c;
extern char *ntp_optarg;
extern int ntp_optind;
extern char *Version;
errflg = 0;
progname = argv[0];
syslogit = 0;
/*
* Decode argument list
*/
while ((c = ntp_getopt(argc, argv, "a:bde:k:o:p:qst:v")) != EOF)
switch (c) {
case 'a':
c = atoi(ntp_optarg);
sys_authenticate = 1;
sys_authkey = c;
break;
case 'b':
always_step++;
break;
case 'd':
++debug;
break;
case 'e':
if (!atolfp(ntp_optarg, &tmp)
|| tmp.l_ui != 0) {
(void) fprintf(stderr,
"%s: encryption delay %s is unlikely\n",
progname, ntp_optarg);
errflg++;
} else {
sys_authdelay = tmp.l_uf;
}
break;
case 'k':
key_file = ntp_optarg;
break;
case 'o':
sys_version = atoi(ntp_optarg);
break;
case 'p':
c = atoi(ntp_optarg);
if (c <= 0 || c > NTP_SHIFT) {
(void) fprintf(stderr,
"%s: number of samples (%d) is invalid\n",
progname, c);
errflg++;
} else {
sys_samples = c;
}
break;
case 'q':
simple_query = 1;
break;
case 's':
syslogit = 1;
break;
case 't':
if (!atolfp(ntp_optarg, &tmp)) {
(void) fprintf(stderr,
"%s: timeout %s is undecodeable\n",
progname, ntp_optarg);
errflg++;
} else {
sys_timeout = ((LFPTOFP(&tmp) * TIMER_HZ)
+ 0x8000) >> 16;
if (sys_timeout == 0)
sys_timeout = 1;
}
break;
case 'v':
verbose = 1;
break;
case '?':
++errflg;
break;
default:
break;
}
sys_maxservers = argc - ntp_optind;
if (errflg || sys_maxservers == 0) {
(void) fprintf(stderr,
"usage: %s [-bqs] [-a key#] [-k file] [-p samples] [-t timeo] server ...\n",
progname);
exit(2);
}
sys_servers = (struct server **)
emalloc(sys_maxservers * sizeof(struct server *));
if (debug || simple_query) {
#ifdef NTP_POSIX_SOURCE
static char buf[BUFSIZ];
setvbuf(stdout, buf, _IOLBF, BUFSIZ);
#else
setlinebuf(stdout);
#endif
}
/*
* Logging. Open the syslog if we have to
*/
if (syslogit) {
#ifndef LOG_DAEMON
openlog("ntpdate", LOG_PID);
#else
#ifndef LOG_NTP
#define LOG_NTP LOG_DAEMON
#endif
openlog("ntpdate", LOG_PID | LOG_NDELAY, LOG_NTP);
if (debug)
setlogmask(LOG_UPTO(LOG_DEBUG));
else
setlogmask(LOG_UPTO(LOG_INFO));
#endif /* LOG_DAEMON */
}
if (debug || verbose)
syslog(LOG_NOTICE, "%s", Version);
/*
* Add servers we are going to be polling
*/
for ( ; ntp_optind < argc; ntp_optind++)
addserver(argv[ntp_optind]);
if (sys_numservers == 0) {
syslog(LOG_ERR, "no servers can be used, exiting");
exit(1);
}
/*
* Initialize the time of day routines and the I/O subsystem
*/
if (sys_authenticate) {
init_auth();
if (!authreadkeys(key_file)) {
syslog(LOG_ERR, "no key file, exitting");
exit(1);
}
if (!authhavekey(sys_authkey)) {
char buf[10];
(void) sprintf(buf, "%lu", (unsigned long)sys_authkey);
syslog(LOG_ERR, "authentication key %s unknown", buf);
exit(1);
}
}
init_io();
init_alarm();
/*
* Set the priority.
*/
#if defined(HAVE_ATT_NICE)
nice (NTPDATE_PRIO);
#endif
#if defined(HAVE_BSD_NICE)
(void) setpriority(PRIO_PROCESS, 0, NTPDATE_PRIO);
#endif
initializing = 0;
was_alarmed = 0;
rbuflist = (struct recvbuf *)0;
while (complete_servers < sys_numservers) {
fd_set rdfdes;
int nfound;
if (alarm_flag) { /* alarmed? */
was_alarmed = 1;
alarm_flag = 0;
}
rbuflist = getrecvbufs(); /* get received buffers */
if (!was_alarmed && rbuflist == (struct recvbuf *)0) {
/*
* Nothing to do. Wait for something.
*/
rdfdes = fdmask;
nfound = select(fd+1, &rdfdes, (fd_set *)0,
(fd_set *)0, (struct timeval *)0);
if (nfound > 0)
input_handler();
else if (nfound == -1 && errno != EINTR) {
syslog(LOG_ERR, "select() error: %m");
}
if (alarm_flag) { /* alarmed? */
was_alarmed = 1;
alarm_flag = 0;
}
rbuflist = getrecvbufs(); /* get received buffers */
}
/*
* Out here, signals are unblocked. Call receive
* procedure for each incoming packet.
*/
while (rbuflist != (struct recvbuf *)0) {
rbuf = rbuflist;
rbuflist = rbuf->next;
receive(rbuf);
freerecvbuf(rbuf);
}
/*
* Call timer to process any timeouts
*/
if (was_alarmed) {
timer();
was_alarmed = 0;
}
/*
* Go around again
*/
}
/*
* When we get here we've completed the polling of all servers.
* Adjust the clock, then exit.
*/
exit(clock_adjust());
}
/*
* transmit - transmit a packet to the given server, or mark it completed.
* This is called by the timeout routine and by the receive
* procedure.
*/
static void
transmit(server)
register struct server *server;
{
struct pkt xpkt;
if (debug)
printf("transmit(%s)\n", ntoa(&server->srcadr));
if (server->filter_nextpt < server->xmtcnt) {
l_fp ts;
/*
* Last message to this server timed out. Shift
* zeros into the filter.
*/
L_CLR(&ts);
server_data(server, 0, &ts, 0);
}
if ((int)server->filter_nextpt >= sys_samples) {
/*
* Got all the data we need. Mark this guy
* completed and return.
*/
server->event_time = 0;
complete_servers++;
return;
}
/*
* If we're here, send another message to the server. Fill in
* the packet and let 'er rip.
*/
xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOTINSYNC,
sys_version, MODE_CLIENT);
xpkt.stratum = STRATUM_TO_PKT(STRATUM_UNSPEC);
xpkt.ppoll = NTP_MINPOLL;
xpkt.precision = NTPDATE_PRECISION;
xpkt.rootdelay = htonl(NTPDATE_DISTANCE);
xpkt.rootdispersion = htonl(NTPDATE_DISP);
xpkt.refid = htonl(NTPDATE_REFID);
L_CLR(&xpkt.reftime);
L_CLR(&xpkt.org);
L_CLR(&xpkt.rec);
/*
* Determine whether to authenticate or not. If so,
* fill in the extended part of the packet and do it.
* If not, just timestamp it and send it away.
*/
if (sys_authenticate) {
int len;
xpkt.keyid = htonl(sys_authkey);
auth1crypt(sys_authkey, (U_LONG *)&xpkt, LEN_PKT_NOMAC);
get_systime(&server->xmt);
L_ADDUF(&server->xmt, sys_authdelay);
HTONL_FP(&server->xmt, &xpkt.xmt);
len = auth2crypt(sys_authkey, (U_LONG *)&xpkt, LEN_PKT_NOMAC);
sendpkt(&(server->srcadr), &xpkt, LEN_PKT_NOMAC + len);
if (debug > 1)
printf("transmit auth to %s\n",
ntoa(&(server->srcadr)));
} else {
get_systime(&(server->xmt));
HTONL_FP(&server->xmt, &xpkt.xmt);
sendpkt(&(server->srcadr), &xpkt, LEN_PKT_NOMAC);
if (debug > 1)
printf("transmit to %s\n", ntoa(&(server->srcadr)));
}
/*
* Update the server timeout and transmit count
*/
server->event_time = current_time + sys_timeout;
server->xmtcnt++;
}
/*
* receive - receive and process an incoming frame
*/
static void
receive(rbufp)
struct recvbuf *rbufp;
{
register struct pkt *rpkt;
register struct server *server;
register s_fp di;
l_fp t10, t23;
l_fp org;
l_fp rec;
l_fp ci;
int has_mac;
int is_authentic;
if (debug)
printf("receive(%s)\n", ntoa(&rbufp->srcadr));
/*
* Check to see if the packet basically looks like something
* intended for us.
*/
if (rbufp->recv_length == LEN_PKT_NOMAC)
has_mac = 0;
else if (rbufp->recv_length >= LEN_PKT_NOMAC)
has_mac = 1;
else {
if (debug)
printf("receive: packet length %d\n",
rbufp->recv_length);
return; /* funny length packet */
}
rpkt = &(rbufp->recv_pkt);
if (PKT_VERSION(rpkt->li_vn_mode) < NTP_OLDVERSION ||
PKT_VERSION(rpkt->li_vn_mode) > NTP_VERSION) {
return;
}
if ((PKT_MODE(rpkt->li_vn_mode) != MODE_SERVER
&& PKT_MODE(rpkt->li_vn_mode) != MODE_PASSIVE)
|| rpkt->stratum > NTP_MAXSTRATUM) {
if (debug)
printf("receive: mode %d stratum %d\n",
PKT_MODE(rpkt->li_vn_mode), rpkt->stratum);
return;
}
/*
* So far, so good. See if this is from a server we know.
*/
server = findserver(&(rbufp->srcadr));
if (server == NULL) {
if (debug)
printf("receive: server not found\n");
return;
}
/*
* Decode the org timestamp and make sure we're getting a response
* to our last request.
*/
NTOHL_FP(&rpkt->org, &org);
if (!L_ISEQU(&org, &server->xmt)) {
if (debug)
printf("receive: pkt.org and peer.xmt differ\n");
return;
}
/*
* Check out the authenticity if we're doing that.
*/
if (!sys_authenticate)
is_authentic = 1;
else {
is_authentic = 0;
if (debug > 3)
printf("receive: rpkt keyid=%ld sys_authkey=%ld decrypt=%ld\n",
(long int)ntohl(rpkt->keyid), (long int)sys_authkey,
(long int)authdecrypt(sys_authkey, (U_LONG *)rpkt,
LEN_PKT_NOMAC));
if (has_mac && ntohl(rpkt->keyid) == sys_authkey &&
authdecrypt(sys_authkey, (U_LONG *)rpkt, LEN_PKT_NOMAC))
is_authentic = 1;
if (debug)
printf("receive: authentication %s\n",
is_authentic ? "passed" : "failed");
}
server->trust <<= 1;
if (!is_authentic)
server->trust |= 1;
/*
* Looks good. Record info from the packet.
*/
server->leap = PKT_LEAP(rpkt->li_vn_mode);
server->stratum = PKT_TO_STRATUM(rpkt->stratum);
server->precision = rpkt->precision;
server->rootdelay = ntohl(rpkt->rootdelay);
server->rootdispersion = ntohl(rpkt->rootdispersion);
server->refid = rpkt->refid;
NTOHL_FP(&rpkt->reftime, &server->reftime);
NTOHL_FP(&rpkt->rec, &rec);
NTOHL_FP(&rpkt->xmt, &server->org);
/*
* Make sure the server is at least somewhat sane. If not, try
* again.
*/
if (L_ISZERO(&rec) || !L_ISHIS(&server->org, &rec)) {
transmit(server);
return;
}
/*
* Calculate the round trip delay (di) and the clock offset (ci).
* We use the equations (reordered from those in the spec):
*
* d = (t2 - t3) - (t1 - t0)
* c = ((t2 - t3) + (t1 - t0)) / 2
*/
t10 = server->org; /* pkt.xmt == t1 */
L_SUB(&t10, &rbufp->recv_time); /* recv_time == t0*/
t23 = rec; /* pkt.rec == t2 */
L_SUB(&t23, &org); /* pkt->org == t3 */
/* now have (t2 - t3) and (t0 - t1). Calculate (ci) and (di) */
ci = t10;
L_ADD(&ci, &t23);
L_RSHIFT(&ci);
/*
* Calculate di in t23 in full precision, then truncate
* to an s_fp.
*/
L_SUB(&t23, &t10);
di = LFPTOFP(&t23);
if (debug > 3)
printf("offset: %s, delay %s\n", lfptoa(&ci, 6), fptoa(di, 5));
di += (FP_SECOND >> (-(int)NTPDATE_PRECISION))
+ (FP_SECOND >> (-(int)server->precision)) + NTP_MAXSKW;
if (di <= 0) { /* value still too raunchy to use? */
L_CLR(&ci);
di = 0;
} else {
di = max(di, NTP_MINDIST);
}
/*
* Shift this data in, then transmit again.
*/
server_data(server, (u_fp) di, &ci, 0);
transmit(server);
}
/*
* server_data - add a sample to the server's filter registers
*/
static void
server_data(server, d, c, e)
register struct server *server;
s_fp d;
l_fp *c;
u_fp e;
{
register int i;
i = server->filter_nextpt;
if (i < NTP_SHIFT) {
server->filter_delay[i] = d;
server->filter_offset[i] = *c;
server->filter_soffset[i] = LFPTOFP(c);
server->filter_error[i] = e;
server->filter_nextpt = i + 1;
}
}
/*
* clock_filter - determine a server's delay, dispersion and offset
*/
static void
clock_filter(server)
register struct server *server;
{
register int i, j;
int ord[NTP_SHIFT];
/*
* Sort indices into increasing delay order
*/
for (i = 0; i < sys_samples; i++)
ord[i] = i;
for (i = 0; i < (sys_samples-1); i++) {
for (j = i+1; j < sys_samples; j++) {
if (server->filter_delay[ord[j]] == 0)
continue;
if (server->filter_delay[ord[i]] == 0
|| (server->filter_delay[ord[i]]
> server->filter_delay[ord[j]])) {
register int tmp;
tmp = ord[i];
ord[i] = ord[j];
ord[j] = tmp;
}
}
}
/*
* Now compute the dispersion, and assign values to delay and
* offset. If there are no samples in the register, delay and
* offset go to zero and dispersion is set to the maximum.
*/
if (server->filter_delay[ord[0]] == 0) {
server->delay = 0;
L_CLR(&server->offset);
server->soffset = 0;
server->dispersion = PEER_MAXDISP;
} else {
register s_fp d;
server->delay = server->filter_delay[ord[0]];
server->offset = server->filter_offset[ord[0]];
server->soffset = LFPTOFP(&server->offset);
server->dispersion = 0;
for (i = 1; i < sys_samples; i++) {
if (server->filter_delay[ord[i]] == 0)
d = PEER_MAXDISP;
else {
d = server->filter_soffset[ord[i]]
- server->filter_soffset[ord[0]];
if (d < 0)
d = -d;
if (d > PEER_MAXDISP)
d = PEER_MAXDISP;
}
/*
* XXX This *knows* PEER_FILTER is 1/2
*/
server->dispersion += (u_fp)(d) >> i;
}
}
/*
* We're done
*/
}
/*
* clock_select - select the pick-of-the-litter clock from the samples
* we've got.
*/
static struct server *
clock_select()
{
register struct server *server;
register int i;
register int nlist;
register s_fp d;
register int j;
register int n;
s_fp local_threshold;
struct server *server_list[NTP_MAXCLOCK];
u_fp server_badness[NTP_MAXCLOCK];
struct server *sys_server;
/*
* This first chunk of code is supposed to go through all
* servers we know about to find the NTP_MAXLIST servers which
* are most likely to succeed. We run through the list
* doing the sanity checks and trying to insert anyone who
* looks okay. We are at all times aware that we should
* only keep samples from the top two strata and we only need
* NTP_MAXLIST of them.
*/
nlist = 0; /* none yet */
for (n = 0; n < sys_numservers; n++) {
server = sys_servers[n];
if (server->delay == 0)
continue; /* no data */
if (server->stratum > NTP_INFIN)
continue; /* stratum no good */
if (server->delay > NTP_MAXWGT) {
continue; /* too far away */
}
if (server->leap == LEAP_NOTINSYNC)
continue; /* he's in trouble */
if (!L_ISHIS(&server->org, &server->reftime)) {
continue; /* very broken host */
}
if ((server->org.l_ui - server->reftime.l_ui)
>= NTP_MAXAGE) {
continue; /* too long without sync */
}
if (server->trust != 0) {
continue;
}
/*
* This one seems sane. Find where he belongs
* on the list.
*/
d = server->dispersion + server->dispersion;
for (i = 0; i < nlist; i++)
if (server->stratum <= server_list[i]->stratum)
break;
for ( ; i < nlist; i++) {
if (server->stratum < server_list[i]->stratum)
break;
if (d < server_badness[i])
break;
}
/*
* If i points past the end of the list, this
* guy is a loser, else stick him in.
*/
if (i >= NTP_MAXLIST)
continue;
for (j = nlist; j > i; j--)
if (j < NTP_MAXLIST) {
server_list[j] = server_list[j-1];
server_badness[j]
= server_badness[j-1];
}
server_list[i] = server;
server_badness[i] = d;
if (nlist < NTP_MAXLIST)
nlist++;
}
/*
* Got the five-or-less best. Cut the list where the number of
* strata exceeds two.
*/
j = 0;
for (i = 1; i < nlist; i++)
if (server_list[i]->stratum > server_list[i-1]->stratum)
if (++j == 2) {
nlist = i;
break;
}
/*
* Whew! What we should have by now is 0 to 5 candidates for
* the job of syncing us. If we have none, we're out of luck.
* If we have one, he's a winner. If we have more, do falseticker
* detection.
*/
if (nlist == 0)
sys_server = 0;
else if (nlist == 1) {
sys_server = server_list[0];
} else {
/*
* Re-sort by stratum, bdelay estimate quality and
* server.delay.
*/
for (i = 0; i < nlist-1; i++)
for (j = i+1; j < nlist; j++) {
if (server_list[i]->stratum
< server_list[j]->stratum)
break; /* already sorted by stratum */
if (server_list[i]->delay
< server_list[j]->delay)
continue;
server = server_list[i];
server_list[i] = server_list[j];
server_list[j] = server;
}
/*
* Calculate the fixed part of the dispersion limit
*/
local_threshold = (FP_SECOND >> (-(int)NTPDATE_PRECISION))
+ NTP_MAXSKW;
/*
* Now drop samples until we're down to one.
*/
while (nlist > 1) {
for (n = 0; n < nlist; n++) {
server_badness[n] = 0;
for (j = 0; j < nlist; j++) {
if (j == n) /* with self? */
continue;
d = server_list[j]->soffset
- server_list[n]->soffset;
if (d < 0) /* absolute value */
d = -d;
/*
* XXX This code *knows* that
* NTP_SELECT is 3/4
*/
for (i = 0; i < j; i++)
d = (d>>1) + (d>>2);
server_badness[n] += d;
}
}
/*
* We now have an array of nlist badness
* coefficients. Find the badest. Find
* the minimum precision while we're at
* it.
*/
i = 0;
n = server_list[0]->precision;;
for (j = 1; j < nlist; j++) {
if (server_badness[j] >= server_badness[i])
i = j;
if (n > server_list[j]->precision)
n = server_list[j]->precision;
}
/*
* i is the index of the server with the worst
* dispersion. If his dispersion is less than
* the threshold, stop now, else delete him and
* continue around again.
*/
if (server_badness[i] < (local_threshold
+ (FP_SECOND >> (-n))))
break;
for (j = i + 1; j < nlist; j++)
server_list[j-1] = server_list[j];
nlist--;
}
/*
* What remains is a list of less than 5 servers. Take
* the best.
*/
sys_server = server_list[0];
}
/*
* That's it. Return our server.
*/
return sys_server;
}
/*
* clock_adjust - process what we've received, and adjust the time
* if we got anything decent.
*/
static int
clock_adjust()
{
register int i;
register struct server *server;
s_fp absoffset;
int dostep;
for (i = 0; i < sys_numservers; i++)
clock_filter(sys_servers[i]);
server = clock_select();
if (debug || simple_query) {
for (i = 0; i < sys_numservers; i++)
printserver(sys_servers[i], stdout);
}
if (server == 0) {
syslog(LOG_ERR,
"no server suitable for synchronization found");
return(1);
}
dostep = 1;
if (!always_step) {
absoffset = server->soffset;
if (absoffset < 0)
absoffset = -absoffset;
if (absoffset < NTPDATE_THRESHOLD)
dostep = 0;
}
if (dostep) {
if (simple_query || l_step_systime(&server->offset)) {
syslog(LOG_NOTICE, "step time server %s offset %s",
ntoa(&server->srcadr),
lfptoa(&server->offset, 6));
}
} else {
if (simple_query || l_adj_systime(&server->offset)) {
syslog(LOG_NOTICE, "adjust time server %s offset %s",
ntoa(&server->srcadr),
lfptoa(&server->offset, 6));
}
}
return(0);
}
/* XXX ELIMINATE: merge BIG slew into adj_systime in lib/systime.c */
/*
* addserver - determine a server's address and allocate a new structure
* for it.
*/
static void
addserver(serv)
char *serv;
{
register struct server *server;
u_long netnum;
static int toomany = 0;
if (sys_numservers >= sys_maxservers) {
if (!toomany) {
/*
* This is actually a `can't happen' now. Leave
* the error message in anyway, though
*/
toomany = 1;
syslog(LOG_ERR,
"too many servers (> %d) specified, remainder not used",
sys_maxservers);
}
return;
}
if (!getnetnum(serv, &netnum)) {
syslog(LOG_ERR, "can't find host %s\n", serv);
return;
}
server = (struct server *)emalloc(sizeof(struct server));
memset((char *)server, 0, sizeof(struct server));
server->srcadr.sin_family = AF_INET;
server->srcadr.sin_addr.s_addr = netnum;
server->srcadr.sin_port = htons(NTP_PORT);
sys_servers[sys_numservers++] = server;
server->event_time = sys_numservers;
}
/*
* findserver - find a server in the list given its address
*/
static struct server *
findserver(addr)
struct sockaddr_in *addr;
{
register int i;
register u_long netnum;
if (htons(addr->sin_port) != NTP_PORT)
return 0;
netnum = addr->sin_addr.s_addr;
for (i = 0; i < sys_numservers; i++) {
if (netnum == sys_servers[i]->srcadr.sin_addr.s_addr)
return sys_servers[i];
}
return 0;
}
/*
* timer - process a timer interrupt
*/
static void
timer()
{
register int i;
/*
* Bump the current idea of the time
*/
current_time++;
/*
* Search through the server list looking for guys
* who's event timers have expired. Give these to
* the transmit routine.
*/
for (i = 0; i < sys_numservers; i++) {
if (sys_servers[i]->event_time != 0
&& sys_servers[i]->event_time <= current_time)
transmit(sys_servers[i]);
}
}
/*
* init_alarm - set up the timer interrupt
*/
static void
init_alarm()
{
struct itimerval itimer;
alarm_flag = 0;
/*
* Set up the alarm interrupt. The first comes 1/(2*TIMER_HZ)
* seconds from now and they continue on every 1/TIMER_HZ seconds.
*/
(void) signal_no_reset(SIGALRM, alarming);
itimer.it_interval.tv_sec = itimer.it_value.tv_sec = 0;
itimer.it_interval.tv_usec = 1000000/TIMER_HZ;
itimer.it_value.tv_usec = 1000000/(TIMER_HZ<<1);
setitimer(ITIMER_REAL, &itimer, (struct itimerval *)0);
}
/*
* alarming - record the occurance of an alarm interrupt
*/
static RETSIGTYPE
alarming(sig)
int sig;
{
alarm_flag++;
}
/*
* We do asynchronous input using the SIGIO facility. A number of
* recvbuf buffers are preallocated for input. In the signal
* handler we poll to see if the socket is ready and read the
* packets from it into the recvbuf's along with a time stamp and
* an indication of the source host and the interface it was received
* through. This allows us to get as accurate receive time stamps
* as possible independent of other processing going on.
*
* We allocate a number of recvbufs equal to the number of servers
* plus 2. This should be plenty.
*/
/*
* recvbuf lists
*/
struct recvbuf *freelist; /* free buffers */
struct recvbuf *fulllist; /* buffers with data */
int full_recvbufs; /* number of full ones */
int free_recvbufs;
/*
* init_io - initialize I/O data and open socket
*/
static void
init_io()
{
register int i;
register struct recvbuf *rb;
/*
* Init buffer free list and stat counters
*/
rb = (struct recvbuf *)
emalloc((sys_numservers + 2) * sizeof(struct recvbuf));
freelist = 0;
for (i = sys_numservers + 2; i > 0; i--) {
rb->next = freelist;
freelist = rb;
rb++;
}
fulllist = 0;
full_recvbufs = 0;
free_recvbufs = sys_numservers + 2;
/*
* Open the socket
*/
/* create a datagram (UDP) socket */
if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
syslog(LOG_ERR, "socket() failed: %m");
exit(1);
/*NOTREACHED*/
}
/*
* bind the socket to the NTP port
*/
if (!debug && !simple_query) {
struct sockaddr_in addr;
memset((char *)&addr, 0, sizeof addr);
addr.sin_family = AF_INET;
addr.sin_port = htons(NTP_PORT);
addr.sin_addr.s_addr = htonl(INADDR_ANY);
if (bind(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
if (errno == EADDRINUSE)
syslog(LOG_ERR,
"the NTP socket is in use, exiting");
else
syslog(LOG_ERR, "bind() fails: %m");
exit(1);
}
}
FD_ZERO(&fdmask);
FD_SET(fd, &fdmask);
/*
* set non-blocking,
*/
#if defined(O_NONBLOCK)
if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) {
syslog(LOG_ERR, "fcntl(FNDELAY|FASYNC) fails: %m");
exit(1);
/*NOTREACHED*/
}
#else /* O_NONBLOCK */
#if defined(FNDELAY)
if (fcntl(fd, F_SETFL, FNDELAY) < 0) {
syslog(LOG_ERR, "fcntl(FNDELAY|FASYNC) fails: %m");
exit(1);
/*NOTREACHED*/
}
#else /* FNDELAY */
Need non blocking I/O
#endif /* FNDELAY */
#endif /* O_NONBLOCK */
}
/* XXX ELIMINATE getrecvbufs (almost) identical to ntpdate.c, ntptrace.c, ntp_io.c */
/*
* getrecvbufs - get receive buffers which have data in them
*
* ***N.B. must be called with SIGIO blocked***
*/
static struct recvbuf *
getrecvbufs()
{
struct recvbuf *rb;
if (full_recvbufs == 0) {
return (struct recvbuf *)0; /* nothing has arrived */
}
/*
* Get the fulllist chain and mark it empty
*/
rb = fulllist;
fulllist = 0;
full_recvbufs = 0;
/*
* Return the chain
*/
return rb;
}
/* XXX ELIMINATE freerecvbuf (almost) identical to ntpdate.c, ntptrace.c, ntp_io.c */
/*
* freerecvbuf - make a single recvbuf available for reuse
*/
static void
freerecvbuf(rb)
struct recvbuf *rb;
{
rb->next = freelist;
freelist = rb;
free_recvbufs++;
}
/*
* sendpkt - send a packet to the specified destination
*/
static void
sendpkt(dest, pkt, len)
struct sockaddr_in *dest;
struct pkt *pkt;
int len;
{
int cc;
cc = sendto(fd, (char *)pkt, len, 0, (struct sockaddr *)dest,
sizeof(struct sockaddr_in));
if (cc == -1) {
if (errno != EWOULDBLOCK && errno != ENOBUFS)
syslog(LOG_ERR, "sendto(%s): %m", ntoa(dest));
}
}
/*
* input_handler - receive packets asynchronously
*/
static void
input_handler()
{
register int n;
register struct recvbuf *rb;
struct timeval tvzero;
int fromlen;
l_fp ts;
fd_set fds;
/*
* Do a poll to see if we have data
*/
for (;;) {
fds = fdmask;
tvzero.tv_sec = tvzero.tv_usec = 0;
n = select(fd+1, &fds, (fd_set *)0, (fd_set *)0, &tvzero);
/*
* If nothing to do, just return. If an error occurred,
* complain and return. If we've got some, freeze a
* timestamp.
*/
if (n == 0)
return;
else if (n == -1) {
syslog(LOG_ERR, "select() error: %m");
return;
}
get_systime(&ts);
/*
* Get a buffer and read the frame. If we
* haven't got a buffer, or this is received
* on the wild card socket, just dump the packet.
*/
if (initializing || free_recvbufs == 0) {
char buf[100];
(void) read(fd, buf, sizeof buf);
continue;
}
rb = freelist;
freelist = rb->next;
free_recvbufs--;
fromlen = sizeof(struct sockaddr_in);
rb->recv_length = recvfrom(fd, (char *)&rb->recv_pkt,
sizeof(rb->recv_pkt), 0,
(struct sockaddr *)&rb->srcadr, &fromlen);
if (rb->recv_length == -1) {
rb->next = freelist;
freelist = rb;
free_recvbufs++;
continue;
}
/*
* Got one. Mark how and when it got here,
* put it on the full list.
*/
rb->recv_time = ts;
rb->next = fulllist;
fulllist = rb;
full_recvbufs++;
}
}
/*
* adj_systime - do a big long slew of the system time
*/
static int
l_adj_systime(ts)
l_fp *ts;
{
struct timeval adjtv, oadjtv;
int isneg = 0;
l_fp offset;
l_fp overshoot;
/*
* Take the absolute value of the offset
*/
offset = *ts;
if (L_ISNEG(&offset)) {
isneg = 1;
L_NEG(&offset);
}
#ifndef STEP_SLEW
/*
* Calculate the overshoot. XXX N.B. This code *knows*
* ADJ_OVERSHOOT is 1/2.
*/
overshoot = offset;
L_RSHIFTU(&overshoot);
if (overshoot.l_ui != 0 || (overshoot.l_uf > ADJ_MAXOVERSHOOT)) {
overshoot.l_ui = 0;
overshoot.l_uf = ADJ_MAXOVERSHOOT;
}
L_ADD(&offset, &overshoot);
#endif
TSTOTV(&offset, &adjtv);
if (isneg) {
adjtv.tv_sec = -adjtv.tv_sec;
adjtv.tv_usec = -adjtv.tv_usec;
}
if (adjtv.tv_usec != 0 && !debug) {
if (adjtime(&adjtv, &oadjtv) < 0) {
syslog(LOG_ERR, "Can't adjust the time of day: %m");
return 0;
}
}
return 1;
}
/*
* This fuction is not the same as lib/systime step_systime!!!
*/
static int
l_step_systime(ts)
l_fp *ts;
{
#ifdef SLEWALWAYS
#ifdef STEP_SLEW
l_fp ftmp;
int isneg;
int n;
if (debug) return 1;
/*
* Take the absolute value of the offset
*/
ftmp = ts;
if (L_ISNEG(&ftmp)) {
L_NEG(&tmp);
isneg = 1;
} else
isneg = 0;
if (tmp_ui >= 3) { /* Step it and slew - we might win */
n = step_systime_real(ts);
if (!n)
return n;
if (isneg)
ts->l_ui = ~0;
else
ts->l_ui = ~0;
}
/*
* Just add adjustment into the current offset. The update
* routine will take care of bringing the system clock into
* line.
*/
#endif
if (debug)
return 1;
#ifdef FORCE_NTPDATE_STEP
return step_systime_real(ts);
#else
l_adj_systime(ts);
return 1;
#endif
#else /* SLEWALWAYS */
if (debug)
return 1;
return step_systime_real(ts);
#endif /* SLEWALWAYS */
}
/*
* getnetnum - given a host name, return its net number
*/
static int
getnetnum(host, num)
char *host;
u_long *num;
{
struct hostent *hp;
if (decodenetnum(host, num)) {
return 1;
} else if ((hp = gethostbyname(host)) != 0) {
memmove((char *)num, hp->h_addr, sizeof(U_LONG));
return (1);
}
return (0);
}
/* XXX ELIMINATE printserver similar in ntptrace.c, ntpdate.c */
/*
* printserver - print detail information for a server
*/
static void
printserver(pp, fp)
register struct server *pp;
FILE *fp;
{
register int i;
char junk[5];
char *str;
if (!debug) {
(void) fprintf(fp, "server %s, stratum %d, offset %s, delay %s\n",
ntoa(&pp->srcadr), pp->stratum,
lfptoa(&pp->offset, 6), fptoa(pp->delay, 5));
return;
}
(void) fprintf(fp, "server %s, port %d\n",
ntoa(&pp->srcadr), ntohs(pp->srcadr.sin_port));
(void) fprintf(fp, "stratum %d, precision %d, leap %c%c, trust %03o\n",
pp->stratum, pp->precision,
pp->leap & 0x2 ? '1' : '0',
pp->leap & 0x1 ? '1' : '0',
pp->trust);
if (pp->stratum == 1) {
junk[4] = 0;
memmove(junk, (char *)&pp->refid, 4);
str = junk;
} else {
str = numtoa(pp->refid);
}
(void) fprintf(fp,
"refid [%s], delay %s, dispersion %s\n",
str, fptoa(pp->delay, 5),
ufptoa(pp->dispersion, 5));
(void) fprintf(fp, "transmitted %d, in filter %d\n",
pp->xmtcnt, pp->filter_nextpt);
(void) fprintf(fp, "reference time: %s\n",
prettydate(&pp->reftime));
(void) fprintf(fp, "originate timestamp: %s\n",
prettydate(&pp->org));
(void) fprintf(fp, "transmit timestamp: %s\n",
prettydate(&pp->xmt));
(void) fprintf(fp, "filter delay: ");
for (i = 0; i < NTP_SHIFT; i++) {
(void) fprintf(fp, " %-8.8s", fptoa(pp->filter_delay[i], 5));
if (i == (NTP_SHIFT>>1)-1)
(void) fprintf(fp, "\n ");
}
(void) fprintf(fp, "\n");
(void) fprintf(fp, "filter offset:");
for (i = 0; i < PEER_SHIFT; i++) {
(void) fprintf(fp, " %-8.8s", lfptoa(&pp->filter_offset[i], 6));
if (i == (PEER_SHIFT>>1)-1)
(void) fprintf(fp, "\n ");
}
(void) fprintf(fp, "\n");
(void) fprintf(fp, "delay %s, dispersion %s\n",
fptoa(pp->delay, 5), ufptoa(pp->dispersion, 5));
(void) fprintf(fp, "offset %s\n\n",
lfptoa(&pp->offset, 6));
}
#if defined(NEED_VSPRINTF)
/*
* This nugget for pre-tahoe 4.3bsd systems
*/
#if !defined(__STDC__) || !__STDC__
#define const
#endif
int
vsprintf(str, fmt, ap)
char *str;
const char *fmt;
va_list ap;
{
FILE f;
int len;
f._flag = _IOWRT+_IOSTRG;
f._ptr = str;
f._cnt = 32767;
len = _doprnt(fmt, ap, &f);
*f._ptr = 0;
return (len);
}
#endif
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