4 * This module contains the private function __rpc_get_time_offset()
5 * which will return the difference in seconds between the local system's
6 * notion of time and a remote server's notion of time. This must be
7 * possible without calling any functions that may invoke the name
8 * service. (netdir_getbyxxx, getXbyY, etc). The function is used in the
9 * synchronize call of the authdes code to synchronize clocks between
10 * NIS+ clients and their servers.
12 * Note to minimize the amount of duplicate code, portions of the
13 * synchronize() function were folded into this code, and the synchronize
14 * call becomes simply a wrapper around this function. Further, if this
15 * function is called with a timehost it *DOES* recurse to the name
16 * server so don't use it in that mode if you are doing name service code.
18 * Copyright (c) 1992 Sun Microsystems Inc.
19 * All rights reserved.
22 * When called a client handle to a RPCBIND process is created
23 * and destroyed. Two strings "netid" and "uaddr" are malloc'd
24 * and returned. The SIGALRM processing is modified only if
25 * needed to deal with TCP connections.
28 #include <sys/cdefs.h>
35 #include <sys/signal.h>
36 #include <sys/errno.h>
37 #include <sys/socket.h>
38 #include <netinet/in.h>
39 #include <arpa/inet.h>
41 #include <rpc/rpc_com.h>
42 #include <rpc/rpcb_prot.h>
43 //#include <clnt_soc.h>
44 #include <sys/select.h>
46 #include <rpcsvc/nis.h>
50 #define msg(x) printf("ERROR: %s\n", x)
51 /* #define msg(x) syslog(LOG_ERR, "%s", x) */
56 static int saw_alarm = 0;
67 * The internet time server defines the epoch to be Jan 1, 1900
68 * whereas UNIX defines it to be Jan 1, 1970. To adjust the result
69 * from internet time-service time, into UNIX time we subtract the
72 #define NYEARS (1970 - 1900)
73 #define TOFFSET ((u_long)60*60*24*(365*NYEARS + (NYEARS/4)))
77 * Stolen from rpc.nisd:
78 * Turn a 'universal address' into a struct sockaddr_in.
81 static int uaddr_to_sockaddr(uaddr, sin)
86 struct sockaddr_in *sin;
88 unsigned char p_bytes[2];
92 i = sscanf(uaddr, "%lu.%lu.%lu.%lu.%lu.%lu", &a[0], &a[1], &a[2],
98 for (i = 0; i < 4; i++)
99 sin->sin_addr.s_addr |= (a[i] & 0x000000FF) << (8 * i);
101 p_bytes[0] = (unsigned char)a[4] & 0x000000FF;
102 p_bytes[1] = (unsigned char)a[5] & 0x000000FF;
104 sin->sin_family = AF_INET; /* always */
105 bcopy((char *)&p_bytes, (char *)&sin->sin_port, 2);
113 * Free the strings that were strduped into the eps structure.
122 for (i = 0; i < num; i++) {
133 * This function constructs a nis_server structure description for the
134 * indicated hostname.
136 * NOTE: There is a chance we may end up recursing here due to the
137 * fact that gethostbyname() could do an NIS search. Ideally, the
138 * NIS+ server will call __rpc_get_time_offset() with the nis_server
139 * structure already populated.
142 get_server(sin, host, srv, eps, maxep)
143 struct sockaddr_in *sin;
144 char *host; /* name of the time host */
145 nis_server *srv; /* nis_server struct to use. */
146 endpoint eps[]; /* array of endpoints */
147 int maxep; /* max array size */
152 struct hostent dummy;
155 if (host == NULL && sin == NULL)
159 he = gethostbyname(host);
164 ptr[0] = (char *)&sin->sin_addr.s_addr;
166 dummy.h_addr_list = ptr;
170 * This is lame. We go around once for TCP, then again
173 for (i = 0; (he->h_addr_list[i] != NULL) && (num_ep < maxep);
177 a = (struct in_addr *)he->h_addr_list[i];
178 snprintf(hname, sizeof(hname), "%s.0.111", inet_ntoa(*a));
179 eps[num_ep].uaddr = strdup(hname);
180 eps[num_ep].family = strdup("inet");
181 eps[num_ep].proto = strdup("tcp");
184 for (i = 0; (he->h_addr_list[i] != NULL) && (num_ep < maxep);
188 a = (struct in_addr *)he->h_addr_list[i];
189 snprintf(hname, sizeof(hname), "%s.0.111", inet_ntoa(*a));
190 eps[num_ep].uaddr = strdup(hname);
191 eps[num_ep].family = strdup("inet");
192 eps[num_ep].proto = strdup("udp");
195 srv->name = (nis_name) host;
196 srv->ep.ep_len = num_ep;
197 srv->ep.ep_val = eps;
198 srv->key_type = NIS_PK_NONE;
199 srv->pkey.n_bytes = NULL;
205 * __rpc_get_time_offset()
207 * This function uses a nis_server structure to contact the a remote
208 * machine (as named in that structure) and returns the offset in time
209 * between that machine and this one. This offset is returned in seconds
210 * and may be positive or negative.
212 * The first time through, a lot of fiddling is done with the netconfig
213 * stuff to find a suitable transport. The function is very aggressive
214 * about choosing UDP or at worst TCP if it can. This is because
215 * those transports support both the RCPBIND call and the internet
218 * Once through, *uaddr is set to the universal address of
219 * the machine and *netid is set to the local netid for the transport
220 * that uaddr goes with. On the second call, the netconfig stuff
221 * is skipped and the uaddr/netid pair are used to fetch the netconfig
222 * structure and to then contact the machine for the time.
224 * td = "server" - "client"
227 __rpc_get_time_offset(td, srv, thost, uaddr, netid)
228 struct timeval *td; /* Time difference */
229 nis_server *srv; /* NIS Server description */
230 char *thost; /* if no server, this is the timehost */
231 char **uaddr; /* known universal address */
232 struct sockaddr_in *netid; /* known network identifier */
234 CLIENT *clnt; /* Client handle */
235 endpoint *ep, /* useful endpoints */
236 *useep = NULL; /* endpoint of xp */
237 char *useua = NULL; /* uaddr of selected xp */
238 int epl, i; /* counters */
239 enum clnt_stat status; /* result of clnt_call */
240 u_long thetime, delta;
244 int udp_ep = -1, tcp_ep = -1;
246 char ut[64], ipuaddr[64];
249 void (*oldsig)() = NULL; /* old alarm handler */
250 struct sockaddr_in sin;
259 * First check to see if we need to find and address for this
262 if (*uaddr == NULL) {
263 if ((srv != NULL) && (thost != NULL)) {
264 msg("both timehost and srv pointer used!");
268 srv = get_server(netid, thost, &tsrv, teps, 32);
270 msg("unable to contruct server data.");
273 needfree = 1; /* need to free data in endpoints */
277 epl = srv->ep.ep_len;
279 /* Identify the TCP and UDP endpoints */
281 (i < epl) && ((udp_ep == -1) || (tcp_ep == -1)); i++) {
282 if (strcasecmp(ep[i].proto, "udp") == 0)
284 if (strcasecmp(ep[i].proto, "tcp") == 0)
288 /* Check to see if it is UDP or TCP */
291 useua = ep[tcp_ep].uaddr;
293 } else if (udp_ep > -1) {
295 useua = ep[udp_ep].uaddr;
300 msg("no acceptable transport endpoints.");
302 free_eps(teps, tsrv.ep.ep_len);
308 * Create a sockaddr from the uaddr.
313 /* Fixup test for NIS+ */
314 sscanf(useua, "%d.%d.%d.%d.", &a1, &a2, &a3, &a4);
315 sprintf(ipuaddr, "%d.%d.%d.%d.0.111", a1, a2, a3, a4);
318 bzero((char *)&sin, sizeof(sin));
319 if (uaddr_to_sockaddr(useua, &sin)) {
320 msg("unable to translate uaddr to sockaddr.");
322 free_eps(teps, tsrv.ep.ep_len);
327 * Create the client handle to rpcbind. Note we always try
328 * version 3 since that is the earliest version that supports
329 * the RPCB_GETTIME call. Also it is the version that comes
330 * standard with SVR4. Since most everyone supports TCP/IP
331 * we could consider trying the rtime call first.
333 clnt = clnttcp_create(&sin, RPCBPROG, RPCBVERS, &s, 0, 0);
335 msg("unable to create client handle to rpcbind.");
337 free_eps(teps, tsrv.ep.ep_len);
344 status = clnt_call(clnt, RPCBPROC_GETTIME, (xdrproc_t)xdr_void, NULL,
345 (xdrproc_t)xdr_u_long, &thetime, tv);
347 * The only error we check for is anything but success. In
348 * fact we could have seen PROGMISMATCH if talking to a 4.1
349 * machine (pmap v2) or TIMEDOUT if the net was busy.
351 if (status == RPC_SUCCESS)
356 /* Blow away possible stale CLNT handle. */
363 * Convert PMAP address into timeservice address
364 * We take advantage of the fact that we "know" what
365 * the universal address looks like for inet transports.
367 * We also know that the internet timeservice is always
368 * listening on port 37.
370 sscanf(useua, "%d.%d.%d.%d.", &a1, &a2, &a3, &a4);
371 sprintf(ut, "%d.%d.%d.%d.0.37", a1, a2, a3, a4);
373 if (uaddr_to_sockaddr(ut, &sin)) {
374 msg("cannot convert timeservice uaddr to sockaddr.");
378 s = socket(AF_INET, type, 0);
380 msg("unable to open fd to network.");
385 * Now depending on whether or not we're talking to
386 * UDP we set a timeout or not.
388 if (type == SOCK_DGRAM) {
389 struct timeval timeout = { 20, 0 };
390 struct sockaddr_in from;
394 if (sendto(s, &thetime, sizeof(thetime), 0,
395 (struct sockaddr *)&sin, sizeof(sin)) == -1) {
396 msg("udp : sendto failed.");
402 res = select(_rpc_dtablesize(), &readfds,
403 (fd_set *)NULL, (fd_set *)NULL, &timeout);
404 } while (res < 0 && errno == EINTR);
408 res = recvfrom(s, (char *)&thetime, sizeof(thetime), 0,
409 (struct sockaddr *)&from, &len);
411 msg("recvfrom failed on udp transport.");
418 oldsig = (void (*)())signal(SIGALRM, alarm_hndler);
419 saw_alarm = 0; /* global tracking the alarm */
420 alarm(20); /* only wait 20 seconds */
421 res = connect(s, (struct sockaddr *)&sin, sizeof(sin));
423 msg("failed to connect to tcp endpoint.");
427 msg("alarm caught it, must be unreachable.");
430 res = read(s, (char *)&thetime, sizeof(thetime));
431 if (res != sizeof(thetime)) {
433 msg("timed out TCP call.");
435 msg("wrong size of results returned");
447 thetime = ntohl(thetime);
448 thetime = thetime - TOFFSET; /* adjust to UNIX time */
453 gettimeofday(&tv, 0);
457 * clean up our allocated data structures.
460 if (s != RPC_ANYSOCK)
466 alarm(0); /* reset that alarm if its outstanding */
468 signal(SIGALRM, oldsig);
472 * note, don't free uaddr strings until after we've made a
477 *uaddr = strdup(useua);
479 /* Round to the nearest second */
480 tv.tv_sec += (tv.tv_sec > 500000) ? 1 : 0;
481 delta = (thetime > tv.tv_sec) ? thetime - tv.tv_sec :
483 td->tv_sec = (thetime < tv.tv_sec) ? - delta : delta;
486 msg("unable to get the server's time.");
490 free_eps(teps, tsrv.ep.ep_len);