xref: /freebsd/sys/rpc/clnt_rc.c (revision 6580f5c38dd5b01aeeaed16b370f1a12423437f0)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2008 Isilon Inc http://www.isilon.com/
5  * Authors: Doug Rabson <dfr@rabson.org>
6  * Developed with Red Inc: Alfred Perlstein <alfred@freebsd.org>
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/kernel.h>
33 #include <sys/limits.h>
34 #include <sys/lock.h>
35 #include <sys/malloc.h>
36 #include <sys/mbuf.h>
37 #include <sys/mutex.h>
38 #include <sys/pcpu.h>
39 #include <sys/proc.h>
40 #include <sys/socket.h>
41 #include <sys/socketvar.h>
42 #include <sys/time.h>
43 #include <sys/uio.h>
44 
45 #include <netinet/tcp.h>
46 
47 #include <rpc/rpc.h>
48 #include <rpc/rpc_com.h>
49 #include <rpc/krpc.h>
50 #include <rpc/rpcsec_tls.h>
51 
52 static enum clnt_stat clnt_reconnect_call(CLIENT *, struct rpc_callextra *,
53     rpcproc_t, struct mbuf *, struct mbuf **, struct timeval);
54 static void clnt_reconnect_geterr(CLIENT *, struct rpc_err *);
55 static bool_t clnt_reconnect_freeres(CLIENT *, xdrproc_t, void *);
56 static void clnt_reconnect_abort(CLIENT *);
57 static bool_t clnt_reconnect_control(CLIENT *, u_int, void *);
58 static void clnt_reconnect_close(CLIENT *);
59 static void clnt_reconnect_destroy(CLIENT *);
60 
61 static const struct clnt_ops clnt_reconnect_ops = {
62 	.cl_call =	clnt_reconnect_call,
63 	.cl_abort =	clnt_reconnect_abort,
64 	.cl_geterr =	clnt_reconnect_geterr,
65 	.cl_freeres =	clnt_reconnect_freeres,
66 	.cl_close =	clnt_reconnect_close,
67 	.cl_destroy =	clnt_reconnect_destroy,
68 	.cl_control =	clnt_reconnect_control
69 };
70 
71 static int	fake_wchan;
72 
73 CLIENT *
74 clnt_reconnect_create(
75 	struct netconfig *nconf,	/* network type */
76 	struct sockaddr *svcaddr,	/* servers address */
77 	rpcprog_t program,		/* program number */
78 	rpcvers_t version,		/* version number */
79 	size_t sendsz,			/* buffer recv size */
80 	size_t recvsz)			/* buffer send size */
81 {
82 	CLIENT *cl = NULL;		/* client handle */
83 	struct rc_data *rc = NULL;	/* private data */
84 
85 	if (svcaddr == NULL) {
86 		rpc_createerr.cf_stat = RPC_UNKNOWNADDR;
87 		return (NULL);
88 	}
89 
90 	cl = mem_alloc(sizeof (CLIENT));
91 	rc = mem_alloc(sizeof (*rc));
92 	mtx_init(&rc->rc_lock, "rc->rc_lock", NULL, MTX_DEF);
93 	(void) memcpy(&rc->rc_addr, svcaddr, (size_t)svcaddr->sa_len);
94 	rc->rc_nconf = nconf;
95 	rc->rc_prog = program;
96 	rc->rc_vers = version;
97 	rc->rc_sendsz = sendsz;
98 	rc->rc_recvsz = recvsz;
99 	rc->rc_timeout.tv_sec = -1;
100 	rc->rc_timeout.tv_usec = -1;
101 	rc->rc_retry.tv_sec = 3;
102 	rc->rc_retry.tv_usec = 0;
103 	rc->rc_retries = INT_MAX;
104 	rc->rc_privport = FALSE;
105 	rc->rc_waitchan = "rpcrecv";
106 	rc->rc_intr = 0;
107 	rc->rc_connecting = FALSE;
108 	rc->rc_closed = FALSE;
109 	rc->rc_ucred = crdup(curthread->td_ucred);
110 	rc->rc_client = NULL;
111 	rc->rc_tls = false;
112 	rc->rc_tlscertname = NULL;
113 	rc->rc_reconcall = NULL;
114 	rc->rc_reconarg = NULL;
115 
116 	cl->cl_refs = 1;
117 	cl->cl_ops = &clnt_reconnect_ops;
118 	cl->cl_private = (caddr_t)(void *)rc;
119 	cl->cl_auth = authnone_create();
120 	cl->cl_tp = NULL;
121 	cl->cl_netid = NULL;
122 	return (cl);
123 }
124 
125 static enum clnt_stat
126 clnt_reconnect_connect(CLIENT *cl)
127 {
128 	struct thread *td = curthread;
129 	struct rc_data *rc = (struct rc_data *)cl->cl_private;
130 	struct socket *so;
131 	enum clnt_stat stat;
132 	int error;
133 	int one = 1;
134 	struct ucred *oldcred;
135 	CLIENT *newclient = NULL;
136 	uint64_t ssl[3];
137 	uint32_t reterr;
138 
139 	mtx_lock(&rc->rc_lock);
140 	while (rc->rc_connecting) {
141 		error = msleep(rc, &rc->rc_lock,
142 		    rc->rc_intr ? PCATCH : 0, "rpcrecon", 0);
143 		if (error) {
144 			mtx_unlock(&rc->rc_lock);
145 			return (RPC_INTR);
146 		}
147 	}
148 	if (rc->rc_closed) {
149 		mtx_unlock(&rc->rc_lock);
150 		return (RPC_CANTSEND);
151 	}
152 	if (rc->rc_client) {
153 		mtx_unlock(&rc->rc_lock);
154 		return (RPC_SUCCESS);
155 	}
156 
157 	/*
158 	 * My turn to attempt a connect. The rc_connecting variable
159 	 * serializes the following code sequence, so it is guaranteed
160 	 * that rc_client will still be NULL after it is re-locked below,
161 	 * since that is the only place it is set non-NULL.
162 	 */
163 	rc->rc_connecting = TRUE;
164 	mtx_unlock(&rc->rc_lock);
165 
166 	oldcred = td->td_ucred;
167 	td->td_ucred = rc->rc_ucred;
168 	so = __rpc_nconf2socket(rc->rc_nconf);
169 	if (!so) {
170 		stat = rpc_createerr.cf_stat = RPC_TLIERROR;
171 		rpc_createerr.cf_error.re_errno = 0;
172 		td->td_ucred = oldcred;
173 		goto out;
174 	}
175 
176 	if (rc->rc_privport)
177 		bindresvport(so, NULL);
178 
179 	if (rc->rc_nconf->nc_semantics == NC_TPI_CLTS)
180 		newclient = clnt_dg_create(so,
181 		    (struct sockaddr *) &rc->rc_addr, rc->rc_prog, rc->rc_vers,
182 		    rc->rc_sendsz, rc->rc_recvsz);
183 	else {
184 		/*
185 		 * I do not believe a timeout of less than 1sec would make
186 		 * sense here since short delays can occur when a server is
187 		 * temporarily overloaded.
188 		 */
189 		if (rc->rc_timeout.tv_sec > 0 && rc->rc_timeout.tv_usec >= 0) {
190 			error = so_setsockopt(so, SOL_SOCKET, SO_SNDTIMEO,
191 			    &rc->rc_timeout, sizeof(struct timeval));
192 			if (error != 0) {
193 				stat = rpc_createerr.cf_stat = RPC_CANTSEND;
194 				rpc_createerr.cf_error.re_errno = error;
195 				td->td_ucred = oldcred;
196 				goto out;
197 			}
198 		}
199 		newclient = clnt_vc_create(so,
200 		    (struct sockaddr *) &rc->rc_addr, rc->rc_prog, rc->rc_vers,
201 		    rc->rc_sendsz, rc->rc_recvsz, rc->rc_intr);
202 		if (rc->rc_tls && newclient != NULL) {
203 			stat = rpctls_connect(newclient, rc->rc_tlscertname, so,
204 			    ssl, &reterr);
205 			if (stat != RPC_SUCCESS || reterr != RPCTLSERR_OK) {
206 				if (stat == RPC_SUCCESS)
207 					stat = RPC_FAILED;
208 				stat = rpc_createerr.cf_stat = stat;
209 				rpc_createerr.cf_error.re_errno = 0;
210 				CLNT_CLOSE(newclient);
211 				CLNT_RELEASE(newclient);
212 				newclient = NULL;
213 				td->td_ucred = oldcred;
214 				goto out;
215 			}
216 		}
217 		if (newclient != NULL) {
218 			int optval = 1;
219 
220 			(void)so_setsockopt(so, IPPROTO_TCP, TCP_USE_DDP,
221 			    &optval, sizeof(optval));
222 		}
223 		if (newclient != NULL && rc->rc_reconcall != NULL)
224 			(*rc->rc_reconcall)(newclient, rc->rc_reconarg,
225 			    rc->rc_ucred);
226 	}
227 	td->td_ucred = oldcred;
228 
229 	if (!newclient) {
230 		soclose(so);
231 		rc->rc_err = rpc_createerr.cf_error;
232 		stat = rpc_createerr.cf_stat;
233 		goto out;
234 	}
235 
236 	CLNT_CONTROL(newclient, CLSET_FD_CLOSE, 0);
237 	CLNT_CONTROL(newclient, CLSET_CONNECT, &one);
238 	CLNT_CONTROL(newclient, CLSET_TIMEOUT, &rc->rc_timeout);
239 	CLNT_CONTROL(newclient, CLSET_RETRY_TIMEOUT, &rc->rc_retry);
240 	CLNT_CONTROL(newclient, CLSET_WAITCHAN, rc->rc_waitchan);
241 	CLNT_CONTROL(newclient, CLSET_INTERRUPTIBLE, &rc->rc_intr);
242 	if (rc->rc_tls)
243 		CLNT_CONTROL(newclient, CLSET_TLS, ssl);
244 	if (rc->rc_backchannel != NULL)
245 		CLNT_CONTROL(newclient, CLSET_BACKCHANNEL, rc->rc_backchannel);
246 	stat = RPC_SUCCESS;
247 
248 out:
249 	mtx_lock(&rc->rc_lock);
250 	KASSERT(rc->rc_client == NULL, ("rc_client not null"));
251 	if (!rc->rc_closed) {
252 		rc->rc_client = newclient;
253 		newclient = NULL;
254 	}
255 	rc->rc_connecting = FALSE;
256 	wakeup(rc);
257 	mtx_unlock(&rc->rc_lock);
258 
259 	if (newclient) {
260 		/*
261 		 * It has been closed, so discard the new client.
262 		 * nb: clnt_[dg|vc]_close()/clnt_[dg|vc]_destroy() cannot
263 		 * be called with the rc_lock mutex held, since they may
264 		 * msleep() while holding a different mutex.
265 		 */
266 		CLNT_CLOSE(newclient);
267 		CLNT_RELEASE(newclient);
268 	}
269 
270 	return (stat);
271 }
272 
273 static enum clnt_stat
274 clnt_reconnect_call(
275 	CLIENT		*cl,		/* client handle */
276 	struct rpc_callextra *ext,	/* call metadata */
277 	rpcproc_t	proc,		/* procedure number */
278 	struct mbuf	*args,		/* pointer to args */
279 	struct mbuf	**resultsp,	/* pointer to results */
280 	struct timeval	utimeout)
281 {
282 	struct rc_data *rc = (struct rc_data *)cl->cl_private;
283 	CLIENT *client;
284 	enum clnt_stat stat;
285 	int tries, error;
286 
287 	tries = 0;
288 	do {
289 		mtx_lock(&rc->rc_lock);
290 		if (rc->rc_closed) {
291 			mtx_unlock(&rc->rc_lock);
292 			return (RPC_CANTSEND);
293 		}
294 
295 		if (!rc->rc_client) {
296 			mtx_unlock(&rc->rc_lock);
297 			stat = clnt_reconnect_connect(cl);
298 			if (stat == RPC_SYSTEMERROR) {
299 				error = tsleep(&fake_wchan,
300 				    rc->rc_intr ? PCATCH : 0, "rpccon", hz);
301 				if (error == EINTR || error == ERESTART)
302 					return (RPC_INTR);
303 				tries++;
304 				if (tries >= rc->rc_retries)
305 					return (stat);
306 				continue;
307 			}
308 			if (stat != RPC_SUCCESS)
309 				return (stat);
310 			mtx_lock(&rc->rc_lock);
311 		}
312 
313 		if (!rc->rc_client) {
314 			mtx_unlock(&rc->rc_lock);
315 			stat = RPC_FAILED;
316 			continue;
317 		}
318 		CLNT_ACQUIRE(rc->rc_client);
319 		client = rc->rc_client;
320 		mtx_unlock(&rc->rc_lock);
321 		stat = CLNT_CALL_MBUF(client, ext, proc, args,
322 		    resultsp, utimeout);
323 
324 		if (stat != RPC_SUCCESS) {
325 			if (!ext)
326 				CLNT_GETERR(client, &rc->rc_err);
327 		}
328 
329 		if (stat == RPC_TIMEDOUT) {
330 			/*
331 			 * Check for async send misfeature for NLM
332 			 * protocol.
333 			 */
334 			if ((rc->rc_timeout.tv_sec == 0
335 				&& rc->rc_timeout.tv_usec == 0)
336 			    || (rc->rc_timeout.tv_sec == -1
337 				&& utimeout.tv_sec == 0
338 				&& utimeout.tv_usec == 0)) {
339 				CLNT_RELEASE(client);
340 				break;
341 			}
342 		}
343 
344 		if (stat == RPC_TIMEDOUT || stat == RPC_CANTSEND
345 		    || stat == RPC_CANTRECV) {
346 			tries++;
347 			if (tries >= rc->rc_retries) {
348 				CLNT_RELEASE(client);
349 				break;
350 			}
351 
352 			if (ext && ext->rc_feedback)
353 				ext->rc_feedback(FEEDBACK_RECONNECT, proc,
354 				    ext->rc_feedback_arg);
355 
356 			mtx_lock(&rc->rc_lock);
357 			/*
358 			 * Make sure that someone else hasn't already
359 			 * reconnected by checking if rc_client has changed.
360 			 * If not, we are done with the client and must
361 			 * do CLNT_RELEASE(client) twice to dispose of it,
362 			 * because there is both an initial refcnt and one
363 			 * acquired by CLNT_ACQUIRE() above.
364 			 */
365 			if (rc->rc_client == client) {
366 				rc->rc_client = NULL;
367 				mtx_unlock(&rc->rc_lock);
368 				CLNT_RELEASE(client);
369 			} else {
370 				mtx_unlock(&rc->rc_lock);
371 			}
372 			CLNT_RELEASE(client);
373 		} else {
374 			CLNT_RELEASE(client);
375 			break;
376 		}
377 	} while (stat != RPC_SUCCESS);
378 
379 	KASSERT(stat != RPC_SUCCESS || *resultsp,
380 	    ("RPC_SUCCESS without reply"));
381 
382 	return (stat);
383 }
384 
385 static void
386 clnt_reconnect_geterr(CLIENT *cl, struct rpc_err *errp)
387 {
388 	struct rc_data *rc = (struct rc_data *)cl->cl_private;
389 
390 	*errp = rc->rc_err;
391 }
392 
393 /*
394  * Since this function requires that rc_client be valid, it can
395  * only be called when that is guaranteed to be the case.
396  */
397 static bool_t
398 clnt_reconnect_freeres(CLIENT *cl, xdrproc_t xdr_res, void *res_ptr)
399 {
400 	struct rc_data *rc = (struct rc_data *)cl->cl_private;
401 
402 	return (CLNT_FREERES(rc->rc_client, xdr_res, res_ptr));
403 }
404 
405 /*ARGSUSED*/
406 static void
407 clnt_reconnect_abort(CLIENT *h)
408 {
409 }
410 
411 /*
412  * CLNT_CONTROL() on the client returned by clnt_reconnect_create() must
413  * always be called before CLNT_CALL_MBUF() by a single thread only.
414  */
415 static bool_t
416 clnt_reconnect_control(CLIENT *cl, u_int request, void *info)
417 {
418 	struct rc_data *rc = (struct rc_data *)cl->cl_private;
419 	SVCXPRT *xprt;
420 	size_t slen;
421 	struct rpc_reconupcall *upcp;
422 
423 	if (info == NULL) {
424 		return (FALSE);
425 	}
426 	switch (request) {
427 	case CLSET_TIMEOUT:
428 		rc->rc_timeout = *(struct timeval *)info;
429 		if (rc->rc_client)
430 			CLNT_CONTROL(rc->rc_client, request, info);
431 		break;
432 
433 	case CLGET_TIMEOUT:
434 		*(struct timeval *)info = rc->rc_timeout;
435 		break;
436 
437 	case CLSET_RETRY_TIMEOUT:
438 		rc->rc_retry = *(struct timeval *)info;
439 		if (rc->rc_client)
440 			CLNT_CONTROL(rc->rc_client, request, info);
441 		break;
442 
443 	case CLGET_RETRY_TIMEOUT:
444 		*(struct timeval *)info = rc->rc_retry;
445 		break;
446 
447 	case CLGET_VERS:
448 		*(uint32_t *)info = rc->rc_vers;
449 		break;
450 
451 	case CLSET_VERS:
452 		rc->rc_vers = *(uint32_t *) info;
453 		if (rc->rc_client)
454 			CLNT_CONTROL(rc->rc_client, CLSET_VERS, info);
455 		break;
456 
457 	case CLGET_PROG:
458 		*(uint32_t *)info = rc->rc_prog;
459 		break;
460 
461 	case CLSET_PROG:
462 		rc->rc_prog = *(uint32_t *) info;
463 		if (rc->rc_client)
464 			CLNT_CONTROL(rc->rc_client, request, info);
465 		break;
466 
467 	case CLSET_WAITCHAN:
468 		rc->rc_waitchan = (char *)info;
469 		if (rc->rc_client)
470 			CLNT_CONTROL(rc->rc_client, request, info);
471 		break;
472 
473 	case CLGET_WAITCHAN:
474 		*(const char **) info = rc->rc_waitchan;
475 		break;
476 
477 	case CLSET_INTERRUPTIBLE:
478 		rc->rc_intr = *(int *) info;
479 		if (rc->rc_client)
480 			CLNT_CONTROL(rc->rc_client, request, info);
481 		break;
482 
483 	case CLGET_INTERRUPTIBLE:
484 		*(int *) info = rc->rc_intr;
485 		break;
486 
487 	case CLSET_RETRIES:
488 		rc->rc_retries = *(int *) info;
489 		break;
490 
491 	case CLGET_RETRIES:
492 		*(int *) info = rc->rc_retries;
493 		break;
494 
495 	case CLSET_PRIVPORT:
496 		rc->rc_privport = *(int *) info;
497 		break;
498 
499 	case CLGET_PRIVPORT:
500 		*(int *) info = rc->rc_privport;
501 		break;
502 
503 	case CLSET_BACKCHANNEL:
504 		xprt = (SVCXPRT *)info;
505 		xprt_register(xprt);
506 		rc->rc_backchannel = info;
507 		break;
508 
509 	case CLSET_TLS:
510 		rc->rc_tls = true;
511 		break;
512 
513 	case CLSET_TLSCERTNAME:
514 		slen = strlen(info) + 1;
515 		/*
516 		 * tlscertname with "key.pem" appended to it forms a file
517 		 * name.  As such, the maximum allowable strlen(info) is
518 		 * NAME_MAX - 7. However, "slen" includes the nul termination
519 		 * byte so it can be up to NAME_MAX - 6.
520 		 */
521 		if (slen <= 1 || slen > NAME_MAX - 6)
522 			return (FALSE);
523 		rc->rc_tlscertname = mem_alloc(slen);
524 		strlcpy(rc->rc_tlscertname, info, slen);
525 		break;
526 
527 	case CLSET_RECONUPCALL:
528 		upcp = (struct rpc_reconupcall *)info;
529 		rc->rc_reconcall = upcp->call;
530 		rc->rc_reconarg = upcp->arg;
531 		break;
532 
533 	default:
534 		return (FALSE);
535 	}
536 
537 	return (TRUE);
538 }
539 
540 static void
541 clnt_reconnect_close(CLIENT *cl)
542 {
543 	struct rc_data *rc = (struct rc_data *)cl->cl_private;
544 	CLIENT *client;
545 
546 	mtx_lock(&rc->rc_lock);
547 
548 	if (rc->rc_closed) {
549 		mtx_unlock(&rc->rc_lock);
550 		return;
551 	}
552 
553 	rc->rc_closed = TRUE;
554 	client = rc->rc_client;
555 	rc->rc_client = NULL;
556 
557 	mtx_unlock(&rc->rc_lock);
558 
559 	if (client) {
560 		CLNT_CLOSE(client);
561 		CLNT_RELEASE(client);
562 	}
563 }
564 
565 static void
566 clnt_reconnect_destroy(CLIENT *cl)
567 {
568 	struct rc_data *rc = (struct rc_data *)cl->cl_private;
569 	SVCXPRT *xprt;
570 
571 	if (rc->rc_client)
572 		CLNT_DESTROY(rc->rc_client);
573 	if (rc->rc_backchannel) {
574 		xprt = (SVCXPRT *)rc->rc_backchannel;
575 		KASSERT(xprt->xp_socket == NULL,
576 		    ("clnt_reconnect_destroy: xp_socket not NULL"));
577 		xprt_unregister(xprt);
578 		SVC_RELEASE(xprt);
579 	}
580 	crfree(rc->rc_ucred);
581 	mtx_destroy(&rc->rc_lock);
582 	mem_free(rc->rc_tlscertname, 0);	/* 0 ok, since arg. ignored. */
583 	mem_free(rc->rc_reconarg, 0);
584 	mem_free(rc, sizeof(*rc));
585 	mem_free(cl, sizeof (CLIENT));
586 }
587