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.
38 #include <sys/signal.h>
39 #include <sys/errno.h>
40 #include <sys/socket.h>
41 #include <netinet/in.h>
42 #include <arpa/inet.h>
44 #include <rpc/rpc_com.h>
46 #include <rpcsvc/nis.h>
49 * FreeBSD currently uses RPC 4.0, which uses portmap rather than
50 * rpcbind. Consequently, we need to fake up these values here.
51 * Luckily, the RPCB_GETTIME procedure uses only base XDR data types
52 * so we don't need anything besides these magic numbers.
54 #define RPCBPROG (u_long)100000
55 #define RPCBVERS (u_long)3
56 #define RPCBPROC_GETTIME (u_long)6
59 #define msg(x) printf("ERROR: %s\n", x)
60 /* #define msg(x) syslog(LOG_ERR, "%s", x) */
65 static int saw_alarm = 0;
76 * The internet time server defines the epoch to be Jan 1, 1900
77 * whereas UNIX defines it to be Jan 1, 1970. To adjust the result
78 * from internet time-service time, into UNIX time we subtract the
81 #define NYEARS (1970 - 1900)
82 #define TOFFSET ((u_long)60*60*24*(365*NYEARS + (NYEARS/4)))
86 * Stolen from rpc.nisd:
87 * Turn a 'universal address' into a struct sockaddr_in.
90 static int uaddr_to_sockaddr(uaddr, sin)
95 struct sockaddr_in *sin;
97 unsigned char p_bytes[2];
101 i = sscanf(uaddr, "%lu.%lu.%lu.%lu.%lu.%lu", &a[0], &a[1], &a[2],
102 &a[3], &a[4], &a[5]);
107 for (i = 0; i < 4; i++)
108 sin->sin_addr.s_addr |= (a[i] & 0x000000FF) << (8 * i);
110 p_bytes[0] = (unsigned char)a[4] & 0x000000FF;
111 p_bytes[1] = (unsigned char)a[5] & 0x000000FF;
113 sin->sin_family = AF_INET; /* always */
114 bcopy((char *)&p_bytes, (char *)&sin->sin_port, 2);
122 * Free the strings that were strduped into the eps structure.
131 for (i = 0; i < num; i++) {
142 * This function constructs a nis_server structure description for the
143 * indicated hostname.
145 * NOTE: There is a chance we may end up recursing here due to the
146 * fact that gethostbyname() could do an NIS search. Ideally, the
147 * NIS+ server will call __rpc_get_time_offset() with the nis_server
148 * structure already populated.
151 get_server(sin, host, srv, eps, maxep)
152 struct sockaddr_in *sin;
153 char *host; /* name of the time host */
154 nis_server *srv; /* nis_server struct to use. */
155 endpoint eps[]; /* array of endpoints */
156 int maxep; /* max array size */
161 struct hostent dummy;
164 if (host == NULL && sin == NULL)
168 he = gethostbyname(host);
173 ptr[0] = (char *)&sin->sin_addr.s_addr;
175 dummy.h_addr_list = ptr;
179 * This is lame. We go around once for TCP, then again
182 for (i = 0; (he->h_addr_list[i] != NULL) && (num_ep < maxep);
186 a = (struct in_addr *)he->h_addr_list[i];
187 snprintf(hname, sizeof(hname), "%s.0.111", inet_ntoa(*a));
188 eps[num_ep].uaddr = strdup(hname);
189 eps[num_ep].family = strdup("inet");
190 eps[num_ep].proto = strdup("tcp");
193 for (i = 0; (he->h_addr_list[i] != NULL) && (num_ep < maxep);
197 a = (struct in_addr *)he->h_addr_list[i];
198 snprintf(hname, sizeof(hname), "%s.0.111", inet_ntoa(*a));
199 eps[num_ep].uaddr = strdup(hname);
200 eps[num_ep].family = strdup("inet");
201 eps[num_ep].proto = strdup("udp");
204 srv->name = (nis_name) host;
205 srv->ep.ep_len = num_ep;
206 srv->ep.ep_val = eps;
207 srv->key_type = NIS_PK_NONE;
208 srv->pkey.n_bytes = NULL;
214 * __rpc_get_time_offset()
216 * This function uses a nis_server structure to contact the a remote
217 * machine (as named in that structure) and returns the offset in time
218 * between that machine and this one. This offset is returned in seconds
219 * and may be positive or negative.
221 * The first time through, a lot of fiddling is done with the netconfig
222 * stuff to find a suitable transport. The function is very aggressive
223 * about choosing UDP or at worst TCP if it can. This is because
224 * those transports support both the RCPBIND call and the internet
227 * Once through, *uaddr is set to the universal address of
228 * the machine and *netid is set to the local netid for the transport
229 * that uaddr goes with. On the second call, the netconfig stuff
230 * is skipped and the uaddr/netid pair are used to fetch the netconfig
231 * structure and to then contact the machine for the time.
233 * td = "server" - "client"
236 __rpc_get_time_offset(td, srv, thost, uaddr, netid)
237 struct timeval *td; /* Time difference */
238 nis_server *srv; /* NIS Server description */
239 char *thost; /* if no server, this is the timehost */
240 char **uaddr; /* known universal address */
241 struct sockaddr_in *netid; /* known network identifier */
243 CLIENT *clnt; /* Client handle */
244 endpoint *ep, /* useful endpoints */
245 *useep = NULL; /* endpoint of xp */
246 char *useua = NULL; /* uaddr of selected xp */
247 int epl, i; /* counters */
248 enum clnt_stat status; /* result of clnt_call */
249 u_long thetime, delta;
253 int udp_ep = -1, tcp_ep = -1;
255 char ut[64], ipuaddr[64];
258 void (*oldsig)() = NULL; /* old alarm handler */
259 struct sockaddr_in sin;
260 int s = RPC_ANYSOCK, len;
267 * First check to see if we need to find and address for this
270 if (*uaddr == NULL) {
271 if ((srv != NULL) && (thost != NULL)) {
272 msg("both timehost and srv pointer used!");
276 srv = get_server(netid, thost, &tsrv, teps, 32);
278 msg("unable to contruct server data.");
281 needfree = 1; /* need to free data in endpoints */
285 epl = srv->ep.ep_len;
287 /* Identify the TCP and UDP endpoints */
289 (i < epl) && ((udp_ep == -1) || (tcp_ep == -1)); i++) {
290 if (strcasecmp(ep[i].proto, "udp") == 0)
292 if (strcasecmp(ep[i].proto, "tcp") == 0)
296 /* Check to see if it is UDP or TCP */
299 useua = ep[tcp_ep].uaddr;
301 } else if (udp_ep > -1) {
303 useua = ep[udp_ep].uaddr;
308 msg("no acceptable transport endpoints.");
310 free_eps(teps, tsrv.ep.ep_len);
316 * Create a sockaddr from the uaddr.
321 /* Fixup test for NIS+ */
322 sscanf(useua, "%d.%d.%d.%d.", &a1, &a2, &a3, &a4);
323 sprintf(ipuaddr, "%d.%d.%d.%d.0.111", a1, a2, a3, a4);
326 bzero((char *)&sin, sizeof(sin));
327 if (uaddr_to_sockaddr(useua, &sin)) {
328 msg("unable to translate uaddr to sockaddr.");
330 free_eps(teps, tsrv.ep.ep_len);
335 * Create the client handle to rpcbind. Note we always try
336 * version 3 since that is the earliest version that supports
337 * the RPCB_GETTIME call. Also it is the version that comes
338 * standard with SVR4. Since most everyone supports TCP/IP
339 * we could consider trying the rtime call first.
341 clnt = clnttcp_create(&sin, RPCBPROG, RPCBVERS, &s, 0, 0);
343 msg("unable to create client handle to rpcbind.");
345 free_eps(teps, tsrv.ep.ep_len);
352 status = clnt_call(clnt, RPCBPROC_GETTIME, xdr_void, NULL,
353 xdr_u_long, (char *)&thetime, tv);
355 * The only error we check for is anything but success. In
356 * fact we could have seen PROGMISMATCH if talking to a 4.1
357 * machine (pmap v2) or TIMEDOUT if the net was busy.
359 if (status == RPC_SUCCESS)
364 /* Blow away possible stale CLNT handle. */
371 * Convert PMAP address into timeservice address
372 * We take advantage of the fact that we "know" what
373 * the universal address looks like for inet transports.
375 * We also know that the internet timeservice is always
376 * listening on port 37.
378 sscanf(useua, "%d.%d.%d.%d.", &a1, &a2, &a3, &a4);
379 sprintf(ut, "%d.%d.%d.%d.0.37", a1, a2, a3, a4);
381 if (uaddr_to_sockaddr(ut, &sin)) {
382 msg("cannot convert timeservice uaddr to sockaddr.");
386 s = socket(AF_INET, type, 0);
388 msg("unable to open fd to network.");
393 * Now depending on whether or not we're talking to
394 * UDP we set a timeout or not.
396 if (type == SOCK_DGRAM) {
397 struct timeval timeout = { 20, 0 };
398 struct sockaddr_in from;
402 if (sendto(s, &thetime, sizeof(thetime), 0,
403 (struct sockaddr *)&sin, sizeof(sin)) == -1) {
404 msg("udp : sendto failed.");
410 res = select(_rpc_dtablesize(), &readfds,
411 (fd_set *)NULL, (fd_set *)NULL, &timeout);
412 } while (res < 0 && errno == EINTR);
416 res = recvfrom(s, (char *)&thetime, sizeof(thetime), 0,
417 (struct sockaddr *)&from, &len);
419 msg("recvfrom failed on udp transport.");
426 oldsig = (void (*)())signal(SIGALRM, alarm_hndler);
427 saw_alarm = 0; /* global tracking the alarm */
428 alarm(20); /* only wait 20 seconds */
429 res = connect(s, (struct sockaddr *)&sin, sizeof(sin));
431 msg("failed to connect to tcp endpoint.");
435 msg("alarm caught it, must be unreachable.");
438 res = read(s, (char *)&thetime, sizeof(thetime));
439 if (res != sizeof(thetime)) {
441 msg("timed out TCP call.");
443 msg("wrong size of results returned");
455 thetime = ntohl(thetime);
456 thetime = thetime - TOFFSET; /* adjust to UNIX time */
461 gettimeofday(&tv, 0);
465 * clean up our allocated data structures.
468 if (s != RPC_ANYSOCK)
474 alarm(0); /* reset that alarm if its outstanding */
476 signal(SIGALRM, oldsig);
480 * note, don't free uaddr strings until after we've made a
485 *uaddr = strdup(useua);
487 /* Round to the nearest second */
488 tv.tv_sec += (tv.tv_sec > 500000) ? 1 : 0;
489 delta = (thetime > tv.tv_sec) ? thetime - tv.tv_sec :
491 td->tv_sec = (thetime < tv.tv_sec) ? - delta : delta;
494 msg("unable to get the server's time.");
498 free_eps(teps, tsrv.ep.ep_len);