1 #pragma ident "@(#)auth_time.c 1.4 92/11/10 SMI"
6 * This module contains the private function __rpc_get_time_offset()
7 * which will return the difference in seconds between the local system's
8 * notion of time and a remote server's notion of time. This must be
9 * possible without calling any functions that may invoke the name
10 * service. (netdir_getbyxxx, getXbyY, etc). The function is used in the
11 * synchronize call of the authdes code to synchronize clocks between
12 * NIS+ clients and their servers.
14 * Note to minimize the amount of duplicate code, portions of the
15 * synchronize() function were folded into this code, and the synchronize
16 * call becomes simply a wrapper around this function. Further, if this
17 * function is called with a timehost it *DOES* recurse to the name
18 * server so don't use it in that mode if you are doing name service code.
20 * Copyright (c) 1992 Sun Microsystems Inc.
21 * All rights reserved.
24 * When called a client handle to a RPCBIND process is created
25 * and destroyed. Two strings "netid" and "uaddr" are malloc'd
26 * and returned. The SIGALRM processing is modified only if
27 * needed to deal with TCP connections.
29 * NOTE: This code has had the crap beaten out it in order to convert
30 * it from TI-RPC back to TD-RPC for use on FreeBSD.
32 * $FreeBSD: src/lib/libc/rpc/auth_time.c,v 1.4 2000/01/27 23:06:35 jasone Exp $
40 #include <sys/signal.h>
41 #include <sys/errno.h>
42 #include <sys/socket.h>
43 #include <netinet/in.h>
44 #include <arpa/inet.h>
46 #include <rpc/rpc_com.h>
48 #include <rpcsvc/nis.h>
51 * FreeBSD currently uses RPC 4.0, which uses portmap rather than
52 * rpcbind. Consequently, we need to fake up these values here.
53 * Luckily, the RPCB_GETTIME procedure uses only base XDR data types
54 * so we don't need anything besides these magic numbers.
56 #define RPCBPROG (u_long)100000
57 #define RPCBVERS (u_long)3
58 #define RPCBPROC_GETTIME (u_long)6
61 #define msg(x) printf("ERROR: %s\n", x)
62 /* #define msg(x) syslog(LOG_ERR, "%s", x) */
67 static int saw_alarm = 0;
78 * The internet time server defines the epoch to be Jan 1, 1900
79 * whereas UNIX defines it to be Jan 1, 1970. To adjust the result
80 * from internet time-service time, into UNIX time we subtract the
83 #define NYEARS (1970 - 1900)
84 #define TOFFSET ((u_long)60*60*24*(365*NYEARS + (NYEARS/4)))
88 * Stolen from rpc.nisd:
89 * Turn a 'universal address' into a struct sockaddr_in.
92 static int uaddr_to_sockaddr(uaddr, sin)
97 struct sockaddr_in *sin;
99 unsigned char p_bytes[2];
103 i = sscanf(uaddr, "%lu.%lu.%lu.%lu.%lu.%lu", &a[0], &a[1], &a[2],
104 &a[3], &a[4], &a[5]);
109 for (i = 0; i < 4; i++)
110 sin->sin_addr.s_addr |= (a[i] & 0x000000FF) << (8 * i);
112 p_bytes[0] = (unsigned char)a[4] & 0x000000FF;
113 p_bytes[1] = (unsigned char)a[5] & 0x000000FF;
115 sin->sin_family = AF_INET; /* always */
116 bcopy((char *)&p_bytes, (char *)&sin->sin_port, 2);
124 * Free the strings that were strduped into the eps structure.
133 for (i = 0; i < num; i++) {
144 * This function constructs a nis_server structure description for the
145 * indicated hostname.
147 * NOTE: There is a chance we may end up recursing here due to the
148 * fact that gethostbyname() could do an NIS search. Ideally, the
149 * NIS+ server will call __rpc_get_time_offset() with the nis_server
150 * structure already populated.
153 get_server(sin, host, srv, eps, maxep)
154 struct sockaddr_in *sin;
155 char *host; /* name of the time host */
156 nis_server *srv; /* nis_server struct to use. */
157 endpoint eps[]; /* array of endpoints */
158 int maxep; /* max array size */
163 struct hostent dummy;
166 if (host == NULL && sin == NULL)
170 he = gethostbyname(host);
175 ptr[0] = (char *)&sin->sin_addr.s_addr;
177 dummy.h_addr_list = ptr;
181 * This is lame. We go around once for TCP, then again
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("tcp");
195 for (i = 0; (he->h_addr_list[i] != NULL) && (num_ep < maxep);
199 a = (struct in_addr *)he->h_addr_list[i];
200 snprintf(hname, sizeof(hname), "%s.0.111", inet_ntoa(*a));
201 eps[num_ep].uaddr = strdup(hname);
202 eps[num_ep].family = strdup("inet");
203 eps[num_ep].proto = strdup("udp");
206 srv->name = (nis_name) host;
207 srv->ep.ep_len = num_ep;
208 srv->ep.ep_val = eps;
209 srv->key_type = NIS_PK_NONE;
210 srv->pkey.n_bytes = NULL;
216 * __rpc_get_time_offset()
218 * This function uses a nis_server structure to contact the a remote
219 * machine (as named in that structure) and returns the offset in time
220 * between that machine and this one. This offset is returned in seconds
221 * and may be positive or negative.
223 * The first time through, a lot of fiddling is done with the netconfig
224 * stuff to find a suitable transport. The function is very aggressive
225 * about choosing UDP or at worst TCP if it can. This is because
226 * those transports support both the RCPBIND call and the internet
229 * Once through, *uaddr is set to the universal address of
230 * the machine and *netid is set to the local netid for the transport
231 * that uaddr goes with. On the second call, the netconfig stuff
232 * is skipped and the uaddr/netid pair are used to fetch the netconfig
233 * structure and to then contact the machine for the time.
235 * td = "server" - "client"
238 __rpc_get_time_offset(td, srv, thost, uaddr, netid)
239 struct timeval *td; /* Time difference */
240 nis_server *srv; /* NIS Server description */
241 char *thost; /* if no server, this is the timehost */
242 char **uaddr; /* known universal address */
243 struct sockaddr_in *netid; /* known network identifier */
245 CLIENT *clnt; /* Client handle */
246 endpoint *ep, /* useful endpoints */
247 *useep = NULL; /* endpoint of xp */
248 char *useua = NULL; /* uaddr of selected xp */
249 int epl, i; /* counters */
250 enum clnt_stat status; /* result of clnt_call */
251 u_long thetime, delta;
255 int udp_ep = -1, tcp_ep = -1;
257 char ut[64], ipuaddr[64];
260 void (*oldsig)() = NULL; /* old alarm handler */
261 struct sockaddr_in sin;
262 int s = RPC_ANYSOCK, len;
269 * First check to see if we need to find and address for this
272 if (*uaddr == NULL) {
273 if ((srv != NULL) && (thost != NULL)) {
274 msg("both timehost and srv pointer used!");
278 srv = get_server(netid, thost, &tsrv, teps, 32);
280 msg("unable to contruct server data.");
283 needfree = 1; /* need to free data in endpoints */
287 epl = srv->ep.ep_len;
289 /* Identify the TCP and UDP endpoints */
291 (i < epl) && ((udp_ep == -1) || (tcp_ep == -1)); i++) {
292 if (strcasecmp(ep[i].proto, "udp") == 0)
294 if (strcasecmp(ep[i].proto, "tcp") == 0)
298 /* Check to see if it is UDP or TCP */
301 useua = ep[tcp_ep].uaddr;
303 } else if (udp_ep > -1) {
305 useua = ep[udp_ep].uaddr;
310 msg("no acceptable transport endpoints.");
312 free_eps(teps, tsrv.ep.ep_len);
318 * Create a sockaddr from the uaddr.
323 /* Fixup test for NIS+ */
324 sscanf(useua, "%d.%d.%d.%d.", &a1, &a2, &a3, &a4);
325 sprintf(ipuaddr, "%d.%d.%d.%d.0.111", a1, a2, a3, a4);
328 bzero((char *)&sin, sizeof(sin));
329 if (uaddr_to_sockaddr(useua, &sin)) {
330 msg("unable to translate uaddr to sockaddr.");
332 free_eps(teps, tsrv.ep.ep_len);
337 * Create the client handle to rpcbind. Note we always try
338 * version 3 since that is the earliest version that supports
339 * the RPCB_GETTIME call. Also it is the version that comes
340 * standard with SVR4. Since most everyone supports TCP/IP
341 * we could consider trying the rtime call first.
343 clnt = clnttcp_create(&sin, RPCBPROG, RPCBVERS, &s, 0, 0);
345 msg("unable to create client handle to rpcbind.");
347 free_eps(teps, tsrv.ep.ep_len);
354 status = clnt_call(clnt, RPCBPROC_GETTIME, xdr_void, NULL,
355 xdr_u_long, (char *)&thetime, tv);
357 * The only error we check for is anything but success. In
358 * fact we could have seen PROGMISMATCH if talking to a 4.1
359 * machine (pmap v2) or TIMEDOUT if the net was busy.
361 if (status == RPC_SUCCESS)
366 /* Blow away possible stale CLNT handle. */
373 * Convert PMAP address into timeservice address
374 * We take advantage of the fact that we "know" what
375 * the universal address looks like for inet transports.
377 * We also know that the internet timeservice is always
378 * listening on port 37.
380 sscanf(useua, "%d.%d.%d.%d.", &a1, &a2, &a3, &a4);
381 sprintf(ut, "%d.%d.%d.%d.0.37", a1, a2, a3, a4);
383 if (uaddr_to_sockaddr(ut, &sin)) {
384 msg("cannot convert timeservice uaddr to sockaddr.");
388 s = socket(AF_INET, type, 0);
390 msg("unable to open fd to network.");
395 * Now depending on whether or not we're talking to
396 * UDP we set a timeout or not.
398 if (type == SOCK_DGRAM) {
399 struct timeval timeout = { 20, 0 };
400 struct sockaddr_in from;
404 if (sendto(s, &thetime, sizeof(thetime), 0,
405 (struct sockaddr *)&sin, sizeof(sin)) == -1) {
406 msg("udp : sendto failed.");
412 res = select(_rpc_dtablesize(), &readfds,
413 (fd_set *)NULL, (fd_set *)NULL, &timeout);
414 } while (res < 0 && errno == EINTR);
418 res = recvfrom(s, (char *)&thetime, sizeof(thetime), 0,
419 (struct sockaddr *)&from, &len);
421 msg("recvfrom failed on udp transport.");
428 oldsig = (void (*)())signal(SIGALRM, alarm_hndler);
429 saw_alarm = 0; /* global tracking the alarm */
430 alarm(20); /* only wait 20 seconds */
431 res = connect(s, (struct sockaddr *)&sin, sizeof(sin));
433 msg("failed to connect to tcp endpoint.");
437 msg("alarm caught it, must be unreachable.");
440 res = _read(s, (char *)&thetime, sizeof(thetime));
441 if (res != sizeof(thetime)) {
443 msg("timed out TCP call.");
445 msg("wrong size of results returned");
457 thetime = ntohl(thetime);
458 thetime = thetime - TOFFSET; /* adjust to UNIX time */
463 gettimeofday(&tv, 0);
467 * clean up our allocated data structures.
470 if (s != RPC_ANYSOCK)
476 alarm(0); /* reset that alarm if its outstanding */
478 signal(SIGALRM, oldsig);
482 * note, don't free uaddr strings until after we've made a
487 *uaddr = strdup(useua);
489 /* Round to the nearest second */
490 tv.tv_sec += (tv.tv_sec > 500000) ? 1 : 0;
491 delta = (thetime > tv.tv_sec) ? thetime - tv.tv_sec :
493 td->tv_sec = (thetime < tv.tv_sec) ? - delta : delta;
496 msg("unable to get the server's time.");
500 free_eps(teps, tsrv.ep.ep_len);