xref: /freebsd/sys/rpc/clnt_dg.c (revision 6580f5c38dd5b01aeeaed16b370f1a12423437f0)
1 /*	$NetBSD: clnt_dg.c,v 1.4 2000/07/14 08:40:41 fvdl Exp $	*/
2 
3 /*-
4  * SPDX-License-Identifier: BSD-3-Clause
5  *
6  * Copyright (c) 2009, Sun Microsystems, Inc.
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions are met:
11  * - Redistributions of source code must retain the above copyright notice,
12  *   this list of conditions and the following disclaimer.
13  * - Redistributions in binary form must reproduce the above copyright notice,
14  *   this list of conditions and the following disclaimer in the documentation
15  *   and/or other materials provided with the distribution.
16  * - Neither the name of Sun Microsystems, Inc. nor the names of its
17  *   contributors may be used to endorse or promote products derived
18  *   from this software without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
21  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
24  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30  * POSSIBILITY OF SUCH DAMAGE.
31  */
32 /*
33  * Copyright (c) 1986-1991 by Sun Microsystems Inc.
34  */
35 
36 /*
37  * Implements a connectionless client side RPC.
38  */
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/lock.h>
44 #include <sys/malloc.h>
45 #include <sys/mbuf.h>
46 #include <sys/mutex.h>
47 #include <sys/pcpu.h>
48 #include <sys/proc.h>
49 #include <sys/socket.h>
50 #include <sys/socketvar.h>
51 #include <sys/time.h>
52 #include <sys/uio.h>
53 
54 #include <net/vnet.h>
55 
56 #include <rpc/rpc.h>
57 #include <rpc/rpc_com.h>
58 
59 
60 #ifdef _FREEFALL_CONFIG
61 /*
62  * Disable RPC exponential back-off for FreeBSD.org systems.
63  */
64 #define	RPC_MAX_BACKOFF		1 /* second */
65 #else
66 #define	RPC_MAX_BACKOFF		30 /* seconds */
67 #endif
68 
69 static bool_t time_not_ok(struct timeval *);
70 static enum clnt_stat clnt_dg_call(CLIENT *, struct rpc_callextra *,
71     rpcproc_t, struct mbuf *, struct mbuf **, struct timeval);
72 static void clnt_dg_geterr(CLIENT *, struct rpc_err *);
73 static bool_t clnt_dg_freeres(CLIENT *, xdrproc_t, void *);
74 static void clnt_dg_abort(CLIENT *);
75 static bool_t clnt_dg_control(CLIENT *, u_int, void *);
76 static void clnt_dg_close(CLIENT *);
77 static void clnt_dg_destroy(CLIENT *);
78 static int clnt_dg_soupcall(struct socket *so, void *arg, int waitflag);
79 
80 static const struct clnt_ops clnt_dg_ops = {
81 	.cl_call =	clnt_dg_call,
82 	.cl_abort =	clnt_dg_abort,
83 	.cl_geterr =	clnt_dg_geterr,
84 	.cl_freeres =	clnt_dg_freeres,
85 	.cl_close =	clnt_dg_close,
86 	.cl_destroy =	clnt_dg_destroy,
87 	.cl_control =	clnt_dg_control
88 };
89 
90 static volatile uint32_t rpc_xid = 0;
91 
92 /*
93  * A pending RPC request which awaits a reply. Requests which have
94  * received their reply will have cr_xid set to zero and cr_mrep to
95  * the mbuf chain of the reply.
96  */
97 struct cu_request {
98 	TAILQ_ENTRY(cu_request) cr_link;
99 	CLIENT			*cr_client;	/* owner */
100 	uint32_t		cr_xid;		/* XID of request */
101 	struct mbuf		*cr_mrep;	/* reply received by upcall */
102 	int			cr_error;	/* any error from upcall */
103 	char			cr_verf[MAX_AUTH_BYTES]; /* reply verf */
104 };
105 
106 TAILQ_HEAD(cu_request_list, cu_request);
107 
108 #define MCALL_MSG_SIZE 24
109 
110 /*
111  * This structure is pointed to by the socket buffer's sb_upcallarg
112  * member. It is separate from the client private data to facilitate
113  * multiple clients sharing the same socket. The cs_lock mutex is used
114  * to protect all fields of this structure, the socket's receive
115  * buffer lock is used to ensure that exactly one of these
116  * structures is installed on the socket.
117  */
118 struct cu_socket {
119 	struct mtx		cs_lock;
120 	int			cs_refs;	/* Count of clients */
121 	struct cu_request_list	cs_pending;	/* Requests awaiting replies */
122 	int			cs_upcallrefs;	/* Refcnt of upcalls in prog.*/
123 };
124 
125 static void clnt_dg_upcallsdone(struct socket *, struct cu_socket *);
126 
127 /*
128  * Private data kept per client handle
129  */
130 struct cu_data {
131 	int			cu_threads;	/* # threads in clnt_vc_call */
132 	bool_t			cu_closing;	/* TRUE if we are closing */
133 	bool_t			cu_closed;	/* TRUE if we are closed */
134 	struct socket		*cu_socket;	/* connection socket */
135 	bool_t			cu_closeit;	/* opened by library */
136 	struct sockaddr_storage	cu_raddr;	/* remote address */
137 	int			cu_rlen;
138 	struct timeval		cu_wait;	/* retransmit interval */
139 	struct timeval		cu_total;	/* total time for the call */
140 	struct rpc_err		cu_error;
141 	uint32_t		cu_xid;
142 	char			cu_mcallc[MCALL_MSG_SIZE]; /* marshalled callmsg */
143 	size_t			cu_mcalllen;
144 	size_t			cu_sendsz;	/* send size */
145 	size_t			cu_recvsz;	/* recv size */
146 	int			cu_async;
147 	int			cu_connect;	/* Use connect(). */
148 	int			cu_connected;	/* Have done connect(). */
149 	const char		*cu_waitchan;
150 	int			cu_waitflag;
151 	int			cu_cwnd;	/* congestion window */
152 	int			cu_sent;	/* number of in-flight RPCs */
153 	bool_t			cu_cwnd_wait;
154 };
155 
156 #define CWNDSCALE	256
157 #define MAXCWND		(32 * CWNDSCALE)
158 
159 /*
160  * Connection less client creation returns with client handle parameters.
161  * Default options are set, which the user can change using clnt_control().
162  * fd should be open and bound.
163  * NB: The rpch->cl_auth is initialized to null authentication.
164  * 	Caller may wish to set this something more useful.
165  *
166  * sendsz and recvsz are the maximum allowable packet sizes that can be
167  * sent and received. Normally they are the same, but they can be
168  * changed to improve the program efficiency and buffer allocation.
169  * If they are 0, use the transport default.
170  *
171  * If svcaddr is NULL, returns NULL.
172  */
173 CLIENT *
174 clnt_dg_create(
175 	struct socket *so,
176 	struct sockaddr *svcaddr,	/* servers address */
177 	rpcprog_t program,		/* program number */
178 	rpcvers_t version,		/* version number */
179 	size_t sendsz,			/* buffer recv size */
180 	size_t recvsz)			/* buffer send size */
181 {
182 	CLIENT *cl = NULL;		/* client handle */
183 	struct cu_data *cu = NULL;	/* private data */
184 	struct cu_socket *cs = NULL;
185 	struct sockbuf *sb;
186 	struct timeval now;
187 	struct rpc_msg call_msg;
188 	struct __rpc_sockinfo si;
189 	XDR xdrs;
190 	int error;
191 	uint32_t newxid;
192 
193 	if (svcaddr == NULL) {
194 		rpc_createerr.cf_stat = RPC_UNKNOWNADDR;
195 		return (NULL);
196 	}
197 
198 	if (!__rpc_socket2sockinfo(so, &si)) {
199 		rpc_createerr.cf_stat = RPC_TLIERROR;
200 		rpc_createerr.cf_error.re_errno = 0;
201 		return (NULL);
202 	}
203 
204 	/*
205 	 * Find the receive and the send size
206 	 */
207 	sendsz = __rpc_get_t_size(si.si_af, si.si_proto, (int)sendsz);
208 	recvsz = __rpc_get_t_size(si.si_af, si.si_proto, (int)recvsz);
209 	if ((sendsz == 0) || (recvsz == 0)) {
210 		rpc_createerr.cf_stat = RPC_TLIERROR; /* XXX */
211 		rpc_createerr.cf_error.re_errno = 0;
212 		return (NULL);
213 	}
214 
215 	cl = mem_alloc(sizeof (CLIENT));
216 
217 	/*
218 	 * Should be multiple of 4 for XDR.
219 	 */
220 	sendsz = rounddown(sendsz + 3, 4);
221 	recvsz = rounddown(recvsz + 3, 4);
222 	cu = mem_alloc(sizeof (*cu));
223 	cu->cu_threads = 0;
224 	cu->cu_closing = FALSE;
225 	cu->cu_closed = FALSE;
226 	(void) memcpy(&cu->cu_raddr, svcaddr, (size_t)svcaddr->sa_len);
227 	cu->cu_rlen = svcaddr->sa_len;
228 	/* Other values can also be set through clnt_control() */
229 	cu->cu_wait.tv_sec = 3;	/* heuristically chosen */
230 	cu->cu_wait.tv_usec = 0;
231 	cu->cu_total.tv_sec = -1;
232 	cu->cu_total.tv_usec = -1;
233 	cu->cu_sendsz = sendsz;
234 	cu->cu_recvsz = recvsz;
235 	cu->cu_async = FALSE;
236 	cu->cu_connect = FALSE;
237 	cu->cu_connected = FALSE;
238 	cu->cu_waitchan = "rpcrecv";
239 	cu->cu_waitflag = 0;
240 	cu->cu_cwnd = MAXCWND / 2;
241 	cu->cu_sent = 0;
242 	cu->cu_cwnd_wait = FALSE;
243 	(void) getmicrotime(&now);
244 	/* Clip at 28bits so that it will not wrap around. */
245 	newxid = __RPC_GETXID(&now) & 0xfffffff;
246 	atomic_cmpset_32(&rpc_xid, 0, newxid);
247 	call_msg.rm_xid = atomic_fetchadd_32(&rpc_xid, 1);
248 	call_msg.rm_call.cb_prog = program;
249 	call_msg.rm_call.cb_vers = version;
250 	xdrmem_create(&xdrs, cu->cu_mcallc, MCALL_MSG_SIZE, XDR_ENCODE);
251 	if (! xdr_callhdr(&xdrs, &call_msg)) {
252 		rpc_createerr.cf_stat = RPC_CANTENCODEARGS;  /* XXX */
253 		rpc_createerr.cf_error.re_errno = 0;
254 		goto err2;
255 	}
256 	cu->cu_mcalllen = XDR_GETPOS(&xdrs);
257 
258 	/*
259 	 * By default, closeit is always FALSE. It is users responsibility
260 	 * to do a close on it, else the user may use clnt_control
261 	 * to let clnt_destroy do it for him/her.
262 	 */
263 	cu->cu_closeit = FALSE;
264 	cu->cu_socket = so;
265 	error = soreserve(so, (u_long)sendsz, (u_long)recvsz);
266 	if (error != 0) {
267 		rpc_createerr.cf_stat = RPC_FAILED;
268 		rpc_createerr.cf_error.re_errno = error;
269 		goto err2;
270 	}
271 
272 	sb = &so->so_rcv;
273 	SOCK_RECVBUF_LOCK(so);
274 recheck_socket:
275 	if (sb->sb_upcall) {
276 		if (sb->sb_upcall != clnt_dg_soupcall) {
277 			SOCK_RECVBUF_UNLOCK(so);
278 			printf("clnt_dg_create(): socket already has an incompatible upcall\n");
279 			goto err2;
280 		}
281 		cs = (struct cu_socket *) sb->sb_upcallarg;
282 		mtx_lock(&cs->cs_lock);
283 		cs->cs_refs++;
284 		mtx_unlock(&cs->cs_lock);
285 	} else {
286 		/*
287 		 * We are the first on this socket - allocate the
288 		 * structure and install it in the socket.
289 		 */
290 		SOCK_RECVBUF_UNLOCK(so);
291 		cs = mem_alloc(sizeof(*cs));
292 		SOCK_RECVBUF_LOCK(so);
293 		if (sb->sb_upcall) {
294 			/*
295 			 * We have lost a race with some other client.
296 			 */
297 			mem_free(cs, sizeof(*cs));
298 			goto recheck_socket;
299 		}
300 		mtx_init(&cs->cs_lock, "cs->cs_lock", NULL, MTX_DEF);
301 		cs->cs_refs = 1;
302 		cs->cs_upcallrefs = 0;
303 		TAILQ_INIT(&cs->cs_pending);
304 		soupcall_set(so, SO_RCV, clnt_dg_soupcall, cs);
305 	}
306 	SOCK_RECVBUF_UNLOCK(so);
307 
308 	cl->cl_refs = 1;
309 	cl->cl_ops = &clnt_dg_ops;
310 	cl->cl_private = (caddr_t)(void *)cu;
311 	cl->cl_auth = authnone_create();
312 	cl->cl_tp = NULL;
313 	cl->cl_netid = NULL;
314 	return (cl);
315 err2:
316 	mem_free(cl, sizeof (CLIENT));
317 	mem_free(cu, sizeof (*cu));
318 
319 	return (NULL);
320 }
321 
322 static enum clnt_stat
323 clnt_dg_call(
324 	CLIENT		*cl,		/* client handle */
325 	struct rpc_callextra *ext,	/* call metadata */
326 	rpcproc_t	proc,		/* procedure number */
327 	struct mbuf	*args,		/* pointer to args */
328 	struct mbuf	**resultsp,	/* pointer to results */
329 	struct timeval	utimeout)	/* seconds to wait before giving up */
330 {
331 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
332 	struct cu_socket *cs;
333 	struct rpc_timers *rt;
334 	AUTH *auth;
335 	struct rpc_err *errp;
336 	enum clnt_stat stat;
337 	XDR xdrs;
338 	struct rpc_msg reply_msg;
339 	bool_t ok;
340 	int retrans;			/* number of re-transmits so far */
341 	int nrefreshes = 2;		/* number of times to refresh cred */
342 	struct timeval *tvp;
343 	int timeout;
344 	int retransmit_time;
345 	int next_sendtime, starttime, rtt, time_waited, tv = 0;
346 	struct sockaddr *sa;
347 	uint32_t xid = 0;
348 	struct mbuf *mreq = NULL, *results;
349 	struct cu_request *cr;
350 	int error;
351 
352 	cs = cu->cu_socket->so_rcv.sb_upcallarg;
353 	cr = malloc(sizeof(struct cu_request), M_RPC, M_WAITOK);
354 
355 	mtx_lock(&cs->cs_lock);
356 
357 	if (cu->cu_closing || cu->cu_closed) {
358 		mtx_unlock(&cs->cs_lock);
359 		free(cr, M_RPC);
360 		return (RPC_CANTSEND);
361 	}
362 	cu->cu_threads++;
363 
364 	if (ext) {
365 		auth = ext->rc_auth;
366 		errp = &ext->rc_err;
367 	} else {
368 		auth = cl->cl_auth;
369 		errp = &cu->cu_error;
370 	}
371 
372 	cr->cr_client = cl;
373 	cr->cr_mrep = NULL;
374 	cr->cr_error = 0;
375 
376 	if (cu->cu_total.tv_usec == -1) {
377 		tvp = &utimeout; /* use supplied timeout */
378 	} else {
379 		tvp = &cu->cu_total; /* use default timeout */
380 	}
381 	if (tvp->tv_sec || tvp->tv_usec)
382 		timeout = tvtohz(tvp);
383 	else
384 		timeout = 0;
385 
386 	if (cu->cu_connect && !cu->cu_connected) {
387 		mtx_unlock(&cs->cs_lock);
388 		error = soconnect(cu->cu_socket,
389 		    (struct sockaddr *)&cu->cu_raddr, curthread);
390 		mtx_lock(&cs->cs_lock);
391 		if (error) {
392 			errp->re_errno = error;
393 			errp->re_status = stat = RPC_CANTSEND;
394 			goto out;
395 		}
396 		cu->cu_connected = 1;
397 	}
398 	if (cu->cu_connected)
399 		sa = NULL;
400 	else
401 		sa = (struct sockaddr *)&cu->cu_raddr;
402 	time_waited = 0;
403 	retrans = 0;
404 	if (ext && ext->rc_timers) {
405 		rt = ext->rc_timers;
406 		if (!rt->rt_rtxcur)
407 			rt->rt_rtxcur = tvtohz(&cu->cu_wait);
408 		retransmit_time = next_sendtime = rt->rt_rtxcur;
409 	} else {
410 		rt = NULL;
411 		retransmit_time = next_sendtime = tvtohz(&cu->cu_wait);
412 	}
413 
414 	starttime = ticks;
415 
416 call_again:
417 	mtx_assert(&cs->cs_lock, MA_OWNED);
418 
419 	xid = atomic_fetchadd_32(&rpc_xid, 1);
420 
421 send_again:
422 	mtx_unlock(&cs->cs_lock);
423 
424 	mreq = m_gethdr(M_WAITOK, MT_DATA);
425 	KASSERT(cu->cu_mcalllen <= MHLEN, ("RPC header too big"));
426 	bcopy(cu->cu_mcallc, mreq->m_data, cu->cu_mcalllen);
427 	mreq->m_len = cu->cu_mcalllen;
428 
429 	/*
430 	 * The XID is the first thing in the request.
431 	 */
432 	*mtod(mreq, uint32_t *) = htonl(xid);
433 
434 	xdrmbuf_create(&xdrs, mreq, XDR_ENCODE);
435 
436 	if (cu->cu_async == TRUE && args == NULL)
437 		goto get_reply;
438 
439 	if ((! XDR_PUTINT32(&xdrs, &proc)) ||
440 	    (! AUTH_MARSHALL(auth, xid, &xdrs,
441 		m_copym(args, 0, M_COPYALL, M_WAITOK)))) {
442 		errp->re_status = stat = RPC_CANTENCODEARGS;
443 		mtx_lock(&cs->cs_lock);
444 		goto out;
445 	}
446 	mreq->m_pkthdr.len = m_length(mreq, NULL);
447 
448 	cr->cr_xid = xid;
449 	mtx_lock(&cs->cs_lock);
450 
451 	/*
452 	 * Try to get a place in the congestion window.
453 	 */
454 	while (cu->cu_sent >= cu->cu_cwnd) {
455 		cu->cu_cwnd_wait = TRUE;
456 		error = msleep(&cu->cu_cwnd_wait, &cs->cs_lock,
457 		    cu->cu_waitflag, "rpccwnd", 0);
458 		if (error) {
459 			errp->re_errno = error;
460 			if (error == EINTR || error == ERESTART)
461 				errp->re_status = stat = RPC_INTR;
462 			else
463 				errp->re_status = stat = RPC_CANTSEND;
464 			goto out;
465 		}
466 	}
467 	cu->cu_sent += CWNDSCALE;
468 
469 	TAILQ_INSERT_TAIL(&cs->cs_pending, cr, cr_link);
470 	mtx_unlock(&cs->cs_lock);
471 
472 	/*
473 	 * sosend consumes mreq.
474 	 */
475 	error = sosend(cu->cu_socket, sa, NULL, mreq, NULL, 0, curthread);
476 	mreq = NULL;
477 
478 	/*
479 	 * sub-optimal code appears here because we have
480 	 * some clock time to spare while the packets are in flight.
481 	 * (We assume that this is actually only executed once.)
482 	 */
483 	reply_msg.acpted_rply.ar_verf.oa_flavor = AUTH_NULL;
484 	reply_msg.acpted_rply.ar_verf.oa_base = cr->cr_verf;
485 	reply_msg.acpted_rply.ar_verf.oa_length = 0;
486 	reply_msg.acpted_rply.ar_results.where = NULL;
487 	reply_msg.acpted_rply.ar_results.proc = (xdrproc_t)xdr_void;
488 
489 	mtx_lock(&cs->cs_lock);
490 	if (error) {
491 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
492 		errp->re_errno = error;
493 		errp->re_status = stat = RPC_CANTSEND;
494 		cu->cu_sent -= CWNDSCALE;
495 		if (cu->cu_cwnd_wait) {
496 			cu->cu_cwnd_wait = FALSE;
497 			wakeup(&cu->cu_cwnd_wait);
498 		}
499 		goto out;
500 	}
501 
502 	/*
503 	 * Check to see if we got an upcall while waiting for the
504 	 * lock.
505 	 */
506 	if (cr->cr_error) {
507 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
508 		errp->re_errno = cr->cr_error;
509 		errp->re_status = stat = RPC_CANTRECV;
510 		cu->cu_sent -= CWNDSCALE;
511 		if (cu->cu_cwnd_wait) {
512 			cu->cu_cwnd_wait = FALSE;
513 			wakeup(&cu->cu_cwnd_wait);
514 		}
515 		goto out;
516 	}
517 	if (cr->cr_mrep) {
518 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
519 		cu->cu_sent -= CWNDSCALE;
520 		if (cu->cu_cwnd_wait) {
521 			cu->cu_cwnd_wait = FALSE;
522 			wakeup(&cu->cu_cwnd_wait);
523 		}
524 		goto got_reply;
525 	}
526 
527 	/*
528 	 * Hack to provide rpc-based message passing
529 	 */
530 	if (timeout == 0) {
531 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
532 		errp->re_status = stat = RPC_TIMEDOUT;
533 		cu->cu_sent -= CWNDSCALE;
534 		if (cu->cu_cwnd_wait) {
535 			cu->cu_cwnd_wait = FALSE;
536 			wakeup(&cu->cu_cwnd_wait);
537 		}
538 		goto out;
539 	}
540 
541 get_reply:
542 	for (;;) {
543 		/* Decide how long to wait. */
544 		if (next_sendtime < timeout)
545 			tv = next_sendtime;
546 		else
547 			tv = timeout;
548 		tv -= time_waited;
549 
550 		if (tv > 0) {
551 			if (cu->cu_closing || cu->cu_closed) {
552 				error = 0;
553 				cr->cr_error = ESHUTDOWN;
554 			} else {
555 				error = msleep(cr, &cs->cs_lock,
556 				    cu->cu_waitflag, cu->cu_waitchan, tv);
557 			}
558 		} else {
559 			error = EWOULDBLOCK;
560 		}
561 
562 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
563 		cu->cu_sent -= CWNDSCALE;
564 		if (cu->cu_cwnd_wait) {
565 			cu->cu_cwnd_wait = FALSE;
566 			wakeup(&cu->cu_cwnd_wait);
567 		}
568 
569 		if (!error) {
570 			/*
571 			 * We were woken up by the upcall.  If the
572 			 * upcall had a receive error, report that,
573 			 * otherwise we have a reply.
574 			 */
575 			if (cr->cr_error) {
576 				errp->re_errno = cr->cr_error;
577 				errp->re_status = stat = RPC_CANTRECV;
578 				goto out;
579 			}
580 
581 			cu->cu_cwnd += (CWNDSCALE * CWNDSCALE
582 			    + cu->cu_cwnd / 2) / cu->cu_cwnd;
583 			if (cu->cu_cwnd > MAXCWND)
584 				cu->cu_cwnd = MAXCWND;
585 
586 			if (rt) {
587 				/*
588 				 * Add one to the time since a tick
589 				 * count of N means that the actual
590 				 * time taken was somewhere between N
591 				 * and N+1.
592 				 */
593 				rtt = ticks - starttime + 1;
594 
595 				/*
596 				 * Update our estimate of the round
597 				 * trip time using roughly the
598 				 * algorithm described in RFC
599 				 * 2988. Given an RTT sample R:
600 				 *
601 				 * RTTVAR = (1-beta) * RTTVAR + beta * |SRTT-R|
602 				 * SRTT = (1-alpha) * SRTT + alpha * R
603 				 *
604 				 * where alpha = 0.125 and beta = 0.25.
605 				 *
606 				 * The initial retransmit timeout is
607 				 * SRTT + 4*RTTVAR and doubles on each
608 				 * retransmision.
609 				 */
610 				if (rt->rt_srtt == 0) {
611 					rt->rt_srtt = rtt;
612 					rt->rt_deviate = rtt / 2;
613 				} else {
614 					int32_t error = rtt - rt->rt_srtt;
615 					rt->rt_srtt += error / 8;
616 					error = abs(error) - rt->rt_deviate;
617 					rt->rt_deviate += error / 4;
618 				}
619 				rt->rt_rtxcur = rt->rt_srtt + 4*rt->rt_deviate;
620 			}
621 
622 			break;
623 		}
624 
625 		/*
626 		 * The sleep returned an error so our request is still
627 		 * on the list. If we got EWOULDBLOCK, we may want to
628 		 * re-send the request.
629 		 */
630 		if (error != EWOULDBLOCK) {
631 			errp->re_errno = error;
632 			if (error == EINTR || error == ERESTART)
633 				errp->re_status = stat = RPC_INTR;
634 			else
635 				errp->re_status = stat = RPC_CANTRECV;
636 			goto out;
637 		}
638 
639 		time_waited = ticks - starttime;
640 
641 		/* Check for timeout. */
642 		if (time_waited > timeout) {
643 			errp->re_errno = EWOULDBLOCK;
644 			errp->re_status = stat = RPC_TIMEDOUT;
645 			goto out;
646 		}
647 
648 		/* Retransmit if necessary. */
649 		if (time_waited >= next_sendtime) {
650 			cu->cu_cwnd /= 2;
651 			if (cu->cu_cwnd < CWNDSCALE)
652 				cu->cu_cwnd = CWNDSCALE;
653 			if (ext && ext->rc_feedback) {
654 				mtx_unlock(&cs->cs_lock);
655 				if (retrans == 0)
656 					ext->rc_feedback(FEEDBACK_REXMIT1,
657 					    proc, ext->rc_feedback_arg);
658 				else
659 					ext->rc_feedback(FEEDBACK_REXMIT2,
660 					    proc, ext->rc_feedback_arg);
661 				mtx_lock(&cs->cs_lock);
662 			}
663 			if (cu->cu_closing || cu->cu_closed) {
664 				errp->re_errno = ESHUTDOWN;
665 				errp->re_status = stat = RPC_CANTRECV;
666 				goto out;
667 			}
668 			retrans++;
669 			/* update retransmit_time */
670 			if (retransmit_time < RPC_MAX_BACKOFF * hz)
671 				retransmit_time = 2 * retransmit_time;
672 			next_sendtime += retransmit_time;
673 			goto send_again;
674 		}
675 		cu->cu_sent += CWNDSCALE;
676 		TAILQ_INSERT_TAIL(&cs->cs_pending, cr, cr_link);
677 	}
678 
679 got_reply:
680 	/*
681 	 * Now decode and validate the response. We need to drop the
682 	 * lock since xdr_replymsg may end up sleeping in malloc.
683 	 */
684 	mtx_unlock(&cs->cs_lock);
685 
686 	if (ext && ext->rc_feedback)
687 		ext->rc_feedback(FEEDBACK_OK, proc, ext->rc_feedback_arg);
688 
689 	xdrmbuf_create(&xdrs, cr->cr_mrep, XDR_DECODE);
690 	ok = xdr_replymsg(&xdrs, &reply_msg);
691 	cr->cr_mrep = NULL;
692 
693 	if (ok) {
694 		if ((reply_msg.rm_reply.rp_stat == MSG_ACCEPTED) &&
695 		    (reply_msg.acpted_rply.ar_stat == SUCCESS))
696 			errp->re_status = stat = RPC_SUCCESS;
697 		else
698 			stat = _seterr_reply(&reply_msg, &(cu->cu_error));
699 
700 		if (errp->re_status == RPC_SUCCESS) {
701 			results = xdrmbuf_getall(&xdrs);
702 			if (! AUTH_VALIDATE(auth, xid,
703 				&reply_msg.acpted_rply.ar_verf,
704 				&results)) {
705 				errp->re_status = stat = RPC_AUTHERROR;
706 				errp->re_why = AUTH_INVALIDRESP;
707 				if (retrans &&
708 				    auth->ah_cred.oa_flavor == RPCSEC_GSS) {
709 					/*
710 					 * If we retransmitted, its
711 					 * possible that we will
712 					 * receive a reply for one of
713 					 * the earlier transmissions
714 					 * (which will use an older
715 					 * RPCSEC_GSS sequence
716 					 * number). In this case, just
717 					 * go back and listen for a
718 					 * new reply. We could keep a
719 					 * record of all the seq
720 					 * numbers we have transmitted
721 					 * so far so that we could
722 					 * accept a reply for any of
723 					 * them here.
724 					 */
725 					XDR_DESTROY(&xdrs);
726 					mtx_lock(&cs->cs_lock);
727 					cu->cu_sent += CWNDSCALE;
728 					TAILQ_INSERT_TAIL(&cs->cs_pending,
729 					    cr, cr_link);
730 					cr->cr_mrep = NULL;
731 					goto get_reply;
732 				}
733 			} else {
734 				*resultsp = results;
735 			}
736 		}		/* end successful completion */
737 		/*
738 		 * If unsuccessful AND error is an authentication error
739 		 * then refresh credentials and try again, else break
740 		 */
741 		else if (stat == RPC_AUTHERROR)
742 			/* maybe our credentials need to be refreshed ... */
743 			if (nrefreshes > 0 &&
744 			    AUTH_REFRESH(auth, &reply_msg)) {
745 				nrefreshes--;
746 				XDR_DESTROY(&xdrs);
747 				mtx_lock(&cs->cs_lock);
748 				goto call_again;
749 			}
750 		/* end of unsuccessful completion */
751 	}	/* end of valid reply message */
752 	else {
753 		errp->re_status = stat = RPC_CANTDECODERES;
754 
755 	}
756 	XDR_DESTROY(&xdrs);
757 	mtx_lock(&cs->cs_lock);
758 out:
759 	mtx_assert(&cs->cs_lock, MA_OWNED);
760 
761 	if (mreq)
762 		m_freem(mreq);
763 	if (cr->cr_mrep)
764 		m_freem(cr->cr_mrep);
765 
766 	cu->cu_threads--;
767 	if (cu->cu_closing)
768 		wakeup(cu);
769 
770 	mtx_unlock(&cs->cs_lock);
771 
772 	if (auth && stat != RPC_SUCCESS)
773 		AUTH_VALIDATE(auth, xid, NULL, NULL);
774 
775 	free(cr, M_RPC);
776 
777 	return (stat);
778 }
779 
780 static void
781 clnt_dg_geterr(CLIENT *cl, struct rpc_err *errp)
782 {
783 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
784 
785 	*errp = cu->cu_error;
786 }
787 
788 static bool_t
789 clnt_dg_freeres(CLIENT *cl, xdrproc_t xdr_res, void *res_ptr)
790 {
791 	XDR xdrs;
792 	bool_t dummy;
793 
794 	xdrs.x_op = XDR_FREE;
795 	dummy = (*xdr_res)(&xdrs, res_ptr);
796 
797 	return (dummy);
798 }
799 
800 /*ARGSUSED*/
801 static void
802 clnt_dg_abort(CLIENT *h)
803 {
804 }
805 
806 static bool_t
807 clnt_dg_control(CLIENT *cl, u_int request, void *info)
808 {
809 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
810 	struct cu_socket *cs;
811 	struct sockaddr *addr;
812 
813 	cs = cu->cu_socket->so_rcv.sb_upcallarg;
814 	mtx_lock(&cs->cs_lock);
815 
816 	switch (request) {
817 	case CLSET_FD_CLOSE:
818 		cu->cu_closeit = TRUE;
819 		mtx_unlock(&cs->cs_lock);
820 		return (TRUE);
821 	case CLSET_FD_NCLOSE:
822 		cu->cu_closeit = FALSE;
823 		mtx_unlock(&cs->cs_lock);
824 		return (TRUE);
825 	}
826 
827 	/* for other requests which use info */
828 	if (info == NULL) {
829 		mtx_unlock(&cs->cs_lock);
830 		return (FALSE);
831 	}
832 	switch (request) {
833 	case CLSET_TIMEOUT:
834 		if (time_not_ok((struct timeval *)info)) {
835 			mtx_unlock(&cs->cs_lock);
836 			return (FALSE);
837 		}
838 		cu->cu_total = *(struct timeval *)info;
839 		break;
840 	case CLGET_TIMEOUT:
841 		*(struct timeval *)info = cu->cu_total;
842 		break;
843 	case CLSET_RETRY_TIMEOUT:
844 		if (time_not_ok((struct timeval *)info)) {
845 			mtx_unlock(&cs->cs_lock);
846 			return (FALSE);
847 		}
848 		cu->cu_wait = *(struct timeval *)info;
849 		break;
850 	case CLGET_RETRY_TIMEOUT:
851 		*(struct timeval *)info = cu->cu_wait;
852 		break;
853 	case CLGET_SVC_ADDR:
854 		/*
855 		 * Slightly different semantics to userland - we use
856 		 * sockaddr instead of netbuf.
857 		 */
858 		memcpy(info, &cu->cu_raddr, cu->cu_raddr.ss_len);
859 		break;
860 	case CLSET_SVC_ADDR:		/* set to new address */
861 		addr = (struct sockaddr *)info;
862 		(void) memcpy(&cu->cu_raddr, addr, addr->sa_len);
863 		break;
864 	case CLGET_XID:
865 		*(uint32_t *)info = atomic_load_32(&rpc_xid);
866 		break;
867 
868 	case CLSET_XID:
869 		/* This will set the xid of the NEXT call */
870 		/* decrement by 1 as clnt_dg_call() increments once */
871 		atomic_store_32(&rpc_xid, *(uint32_t *)info - 1);
872 		break;
873 
874 	case CLGET_VERS:
875 		/*
876 		 * This RELIES on the information that, in the call body,
877 		 * the version number field is the fifth field from the
878 		 * beginning of the RPC header. MUST be changed if the
879 		 * call_struct is changed
880 		 */
881 		*(uint32_t *)info =
882 		    ntohl(*(uint32_t *)(void *)(cu->cu_mcallc +
883 		    4 * BYTES_PER_XDR_UNIT));
884 		break;
885 
886 	case CLSET_VERS:
887 		*(uint32_t *)(void *)(cu->cu_mcallc + 4 * BYTES_PER_XDR_UNIT)
888 			= htonl(*(uint32_t *)info);
889 		break;
890 
891 	case CLGET_PROG:
892 		/*
893 		 * This RELIES on the information that, in the call body,
894 		 * the program number field is the fourth field from the
895 		 * beginning of the RPC header. MUST be changed if the
896 		 * call_struct is changed
897 		 */
898 		*(uint32_t *)info =
899 		    ntohl(*(uint32_t *)(void *)(cu->cu_mcallc +
900 		    3 * BYTES_PER_XDR_UNIT));
901 		break;
902 
903 	case CLSET_PROG:
904 		*(uint32_t *)(void *)(cu->cu_mcallc + 3 * BYTES_PER_XDR_UNIT)
905 			= htonl(*(uint32_t *)info);
906 		break;
907 	case CLSET_ASYNC:
908 		cu->cu_async = *(int *)info;
909 		break;
910 	case CLSET_CONNECT:
911 		cu->cu_connect = *(int *)info;
912 		break;
913 	case CLSET_WAITCHAN:
914 		cu->cu_waitchan = (const char *)info;
915 		break;
916 	case CLGET_WAITCHAN:
917 		*(const char **) info = cu->cu_waitchan;
918 		break;
919 	case CLSET_INTERRUPTIBLE:
920 		if (*(int *) info)
921 			cu->cu_waitflag = PCATCH;
922 		else
923 			cu->cu_waitflag = 0;
924 		break;
925 	case CLGET_INTERRUPTIBLE:
926 		if (cu->cu_waitflag)
927 			*(int *) info = TRUE;
928 		else
929 			*(int *) info = FALSE;
930 		break;
931 	default:
932 		mtx_unlock(&cs->cs_lock);
933 		return (FALSE);
934 	}
935 	mtx_unlock(&cs->cs_lock);
936 	return (TRUE);
937 }
938 
939 static void
940 clnt_dg_close(CLIENT *cl)
941 {
942 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
943 	struct cu_socket *cs;
944 	struct cu_request *cr;
945 
946 	cs = cu->cu_socket->so_rcv.sb_upcallarg;
947 	mtx_lock(&cs->cs_lock);
948 
949 	if (cu->cu_closed) {
950 		mtx_unlock(&cs->cs_lock);
951 		return;
952 	}
953 
954 	if (cu->cu_closing) {
955 		while (cu->cu_closing)
956 			msleep(cu, &cs->cs_lock, 0, "rpcclose", 0);
957 		KASSERT(cu->cu_closed, ("client should be closed"));
958 		mtx_unlock(&cs->cs_lock);
959 		return;
960 	}
961 
962 	/*
963 	 * Abort any pending requests and wait until everyone
964 	 * has finished with clnt_vc_call.
965 	 */
966 	cu->cu_closing = TRUE;
967 	TAILQ_FOREACH(cr, &cs->cs_pending, cr_link) {
968 		if (cr->cr_client == cl) {
969 			cr->cr_xid = 0;
970 			cr->cr_error = ESHUTDOWN;
971 			wakeup(cr);
972 		}
973 	}
974 
975 	while (cu->cu_threads)
976 		msleep(cu, &cs->cs_lock, 0, "rpcclose", 0);
977 
978 	cu->cu_closing = FALSE;
979 	cu->cu_closed = TRUE;
980 
981 	mtx_unlock(&cs->cs_lock);
982 	wakeup(cu);
983 }
984 
985 static void
986 clnt_dg_destroy(CLIENT *cl)
987 {
988 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
989 	struct cu_socket *cs;
990 	struct socket *so = NULL;
991 	bool_t lastsocketref;
992 
993 	cs = cu->cu_socket->so_rcv.sb_upcallarg;
994 	clnt_dg_close(cl);
995 
996 	SOCK_RECVBUF_LOCK(cu->cu_socket);
997 	mtx_lock(&cs->cs_lock);
998 
999 	cs->cs_refs--;
1000 	if (cs->cs_refs == 0) {
1001 		mtx_unlock(&cs->cs_lock);
1002 		soupcall_clear(cu->cu_socket, SO_RCV);
1003 		clnt_dg_upcallsdone(cu->cu_socket, cs);
1004 		SOCK_RECVBUF_UNLOCK(cu->cu_socket);
1005 		mtx_destroy(&cs->cs_lock);
1006 		mem_free(cs, sizeof(*cs));
1007 		lastsocketref = TRUE;
1008 	} else {
1009 		mtx_unlock(&cs->cs_lock);
1010 		SOCK_RECVBUF_UNLOCK(cu->cu_socket);
1011 		lastsocketref = FALSE;
1012 	}
1013 
1014 	if (cu->cu_closeit && lastsocketref) {
1015 		so = cu->cu_socket;
1016 		cu->cu_socket = NULL;
1017 	}
1018 
1019 	if (so)
1020 		soclose(so);
1021 
1022 	if (cl->cl_netid && cl->cl_netid[0])
1023 		mem_free(cl->cl_netid, strlen(cl->cl_netid) +1);
1024 	if (cl->cl_tp && cl->cl_tp[0])
1025 		mem_free(cl->cl_tp, strlen(cl->cl_tp) +1);
1026 	mem_free(cu, sizeof (*cu));
1027 	mem_free(cl, sizeof (CLIENT));
1028 }
1029 
1030 /*
1031  * Make sure that the time is not garbage.  -1 value is allowed.
1032  */
1033 static bool_t
1034 time_not_ok(struct timeval *t)
1035 {
1036 	return (t->tv_sec < -1 || t->tv_sec > 100000000 ||
1037 		t->tv_usec < -1 || t->tv_usec > 1000000);
1038 }
1039 
1040 int
1041 clnt_dg_soupcall(struct socket *so, void *arg, int waitflag)
1042 {
1043 	struct cu_socket *cs = (struct cu_socket *) arg;
1044 	struct uio uio;
1045 	struct mbuf *m;
1046 	struct mbuf *control;
1047 	struct cu_request *cr;
1048 	int error, rcvflag, foundreq;
1049 	uint32_t xid;
1050 
1051 	cs->cs_upcallrefs++;
1052 	uio.uio_resid = 1000000000;
1053 	uio.uio_td = curthread;
1054 	do {
1055 		SOCK_RECVBUF_UNLOCK(so);
1056 		m = NULL;
1057 		control = NULL;
1058 		rcvflag = MSG_DONTWAIT;
1059 		error = soreceive(so, NULL, &uio, &m, &control, &rcvflag);
1060 		if (control)
1061 			m_freem(control);
1062 		SOCK_RECVBUF_LOCK(so);
1063 
1064 		if (error == EWOULDBLOCK)
1065 			break;
1066 
1067 		/*
1068 		 * If there was an error, wake up all pending
1069 		 * requests.
1070 		 */
1071 		if (error) {
1072 			mtx_lock(&cs->cs_lock);
1073 			TAILQ_FOREACH(cr, &cs->cs_pending, cr_link) {
1074 				cr->cr_xid = 0;
1075 				cr->cr_error = error;
1076 				wakeup(cr);
1077 			}
1078 			mtx_unlock(&cs->cs_lock);
1079 			break;
1080 		}
1081 
1082 		/*
1083 		 * The XID is in the first uint32_t of the reply.
1084 		 */
1085 		if (m->m_len < sizeof(xid) && m_length(m, NULL) < sizeof(xid)) {
1086 			/*
1087 			 * Should never happen.
1088 			 */
1089 			m_freem(m);
1090 			continue;
1091 		}
1092 
1093 		m_copydata(m, 0, sizeof(xid), (char *)&xid);
1094 		xid = ntohl(xid);
1095 
1096 		/*
1097 		 * Attempt to match this reply with a pending request.
1098 		 */
1099 		mtx_lock(&cs->cs_lock);
1100 		foundreq = 0;
1101 		TAILQ_FOREACH(cr, &cs->cs_pending, cr_link) {
1102 			if (cr->cr_xid == xid) {
1103 				/*
1104 				 * This one matches. We leave the
1105 				 * reply mbuf in cr->cr_mrep. Set the
1106 				 * XID to zero so that we will ignore
1107 				 * any duplicated replies that arrive
1108 				 * before clnt_dg_call removes it from
1109 				 * the queue.
1110 				 */
1111 				cr->cr_xid = 0;
1112 				cr->cr_mrep = m;
1113 				cr->cr_error = 0;
1114 				foundreq = 1;
1115 				wakeup(cr);
1116 				break;
1117 			}
1118 		}
1119 		mtx_unlock(&cs->cs_lock);
1120 
1121 		/*
1122 		 * If we didn't find the matching request, just drop
1123 		 * it - its probably a repeated reply.
1124 		 */
1125 		if (!foundreq)
1126 			m_freem(m);
1127 	} while (m);
1128 	cs->cs_upcallrefs--;
1129 	if (cs->cs_upcallrefs < 0)
1130 		panic("rpcdg upcall refcnt");
1131 	if (cs->cs_upcallrefs == 0)
1132 		wakeup(&cs->cs_upcallrefs);
1133 	return (SU_OK);
1134 }
1135 
1136 /*
1137  * Wait for all upcalls in progress to complete.
1138  */
1139 static void
1140 clnt_dg_upcallsdone(struct socket *so, struct cu_socket *cs)
1141 {
1142 
1143 	SOCK_RECVBUF_LOCK_ASSERT(so);
1144 
1145 	while (cs->cs_upcallrefs > 0)
1146 		(void) msleep(&cs->cs_upcallrefs, SOCKBUF_MTX(&so->so_rcv), 0,
1147 		    "rpcdgup", 0);
1148 }
1149