xref: /freebsd/sys/rpc/clnt_dg.c (revision bc3f5ec90bde2f3a5e4021d133c89793d68b8c73)
1 /*	$NetBSD: clnt_dg.c,v 1.4 2000/07/14 08:40:41 fvdl Exp $	*/
2 
3 /*-
4  * Copyright (c) 2009, Sun Microsystems, Inc.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions are met:
9  * - Redistributions of source code must retain the above copyright notice,
10  *   this list of conditions and the following disclaimer.
11  * - Redistributions in binary form must reproduce the above copyright notice,
12  *   this list of conditions and the following disclaimer in the documentation
13  *   and/or other materials provided with the distribution.
14  * - Neither the name of Sun Microsystems, Inc. nor the names of its
15  *   contributors may be used to endorse or promote products derived
16  *   from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
22  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28  * POSSIBILITY OF SUCH DAMAGE.
29  */
30 /*
31  * Copyright (c) 1986-1991 by Sun Microsystems Inc.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 #ident	"@(#)clnt_dg.c	1.23	94/04/22 SMI"
36 static char sccsid[] = "@(#)clnt_dg.c 1.19 89/03/16 Copyr 1988 Sun Micro";
37 #endif
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 /*
42  * Implements a connectionless client side RPC.
43  */
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/kernel.h>
48 #include <sys/lock.h>
49 #include <sys/malloc.h>
50 #include <sys/mbuf.h>
51 #include <sys/mutex.h>
52 #include <sys/pcpu.h>
53 #include <sys/proc.h>
54 #include <sys/socket.h>
55 #include <sys/socketvar.h>
56 #include <sys/time.h>
57 #include <sys/uio.h>
58 
59 #include <net/vnet.h>
60 
61 #include <rpc/rpc.h>
62 #include <rpc/rpc_com.h>
63 
64 
65 #ifdef _FREEFALL_CONFIG
66 /*
67  * Disable RPC exponential back-off for FreeBSD.org systems.
68  */
69 #define	RPC_MAX_BACKOFF		1 /* second */
70 #else
71 #define	RPC_MAX_BACKOFF		30 /* seconds */
72 #endif
73 
74 static bool_t time_not_ok(struct timeval *);
75 static enum clnt_stat clnt_dg_call(CLIENT *, struct rpc_callextra *,
76     rpcproc_t, struct mbuf *, struct mbuf **, struct timeval);
77 static void clnt_dg_geterr(CLIENT *, struct rpc_err *);
78 static bool_t clnt_dg_freeres(CLIENT *, xdrproc_t, void *);
79 static void clnt_dg_abort(CLIENT *);
80 static bool_t clnt_dg_control(CLIENT *, u_int, void *);
81 static void clnt_dg_close(CLIENT *);
82 static void clnt_dg_destroy(CLIENT *);
83 static int clnt_dg_soupcall(struct socket *so, void *arg, int waitflag);
84 
85 static struct clnt_ops clnt_dg_ops = {
86 	.cl_call =	clnt_dg_call,
87 	.cl_abort =	clnt_dg_abort,
88 	.cl_geterr =	clnt_dg_geterr,
89 	.cl_freeres =	clnt_dg_freeres,
90 	.cl_close =	clnt_dg_close,
91 	.cl_destroy =	clnt_dg_destroy,
92 	.cl_control =	clnt_dg_control
93 };
94 
95 /*
96  * A pending RPC request which awaits a reply. Requests which have
97  * received their reply will have cr_xid set to zero and cr_mrep to
98  * the mbuf chain of the reply.
99  */
100 struct cu_request {
101 	TAILQ_ENTRY(cu_request) cr_link;
102 	CLIENT			*cr_client;	/* owner */
103 	uint32_t		cr_xid;		/* XID of request */
104 	struct mbuf		*cr_mrep;	/* reply received by upcall */
105 	int			cr_error;	/* any error from upcall */
106 	char			cr_verf[MAX_AUTH_BYTES]; /* reply verf */
107 };
108 
109 TAILQ_HEAD(cu_request_list, cu_request);
110 
111 #define MCALL_MSG_SIZE 24
112 
113 /*
114  * This structure is pointed to by the socket buffer's sb_upcallarg
115  * member. It is separate from the client private data to facilitate
116  * multiple clients sharing the same socket. The cs_lock mutex is used
117  * to protect all fields of this structure, the socket's receive
118  * buffer SOCKBUF_LOCK is used to ensure that exactly one of these
119  * structures is installed on the socket.
120  */
121 struct cu_socket {
122 	struct mtx		cs_lock;
123 	int			cs_refs;	/* Count of clients */
124 	struct cu_request_list	cs_pending;	/* Requests awaiting replies */
125 	int			cs_upcallrefs;	/* Refcnt of upcalls in prog.*/
126 };
127 
128 static void clnt_dg_upcallsdone(struct socket *, struct cu_socket *);
129 
130 /*
131  * Private data kept per client handle
132  */
133 struct cu_data {
134 	int			cu_threads;	/* # threads in clnt_vc_call */
135 	bool_t			cu_closing;	/* TRUE if we are closing */
136 	bool_t			cu_closed;	/* TRUE if we are closed */
137 	struct socket		*cu_socket;	/* connection socket */
138 	bool_t			cu_closeit;	/* opened by library */
139 	struct sockaddr_storage	cu_raddr;	/* remote address */
140 	int			cu_rlen;
141 	struct timeval		cu_wait;	/* retransmit interval */
142 	struct timeval		cu_total;	/* total time for the call */
143 	struct rpc_err		cu_error;
144 	uint32_t		cu_xid;
145 	char			cu_mcallc[MCALL_MSG_SIZE]; /* marshalled callmsg */
146 	size_t			cu_mcalllen;
147 	size_t			cu_sendsz;	/* send size */
148 	size_t			cu_recvsz;	/* recv size */
149 	int			cu_async;
150 	int			cu_connect;	/* Use connect(). */
151 	int			cu_connected;	/* Have done connect(). */
152 	const char		*cu_waitchan;
153 	int			cu_waitflag;
154 	int			cu_cwnd;	/* congestion window */
155 	int			cu_sent;	/* number of in-flight RPCs */
156 	bool_t			cu_cwnd_wait;
157 };
158 
159 #define CWNDSCALE	256
160 #define MAXCWND		(32 * CWNDSCALE)
161 
162 /*
163  * Connection less client creation returns with client handle parameters.
164  * Default options are set, which the user can change using clnt_control().
165  * fd should be open and bound.
166  * NB: The rpch->cl_auth is initialized to null authentication.
167  * 	Caller may wish to set this something more useful.
168  *
169  * sendsz and recvsz are the maximum allowable packet sizes that can be
170  * sent and received. Normally they are the same, but they can be
171  * changed to improve the program efficiency and buffer allocation.
172  * If they are 0, use the transport default.
173  *
174  * If svcaddr is NULL, returns NULL.
175  */
176 CLIENT *
177 clnt_dg_create(
178 	struct socket *so,
179 	struct sockaddr *svcaddr,	/* servers address */
180 	rpcprog_t program,		/* program number */
181 	rpcvers_t version,		/* version number */
182 	size_t sendsz,			/* buffer recv size */
183 	size_t recvsz)			/* buffer send size */
184 {
185 	CLIENT *cl = NULL;		/* client handle */
186 	struct cu_data *cu = NULL;	/* private data */
187 	struct cu_socket *cs = NULL;
188 	struct sockbuf *sb;
189 	struct timeval now;
190 	struct rpc_msg call_msg;
191 	struct __rpc_sockinfo si;
192 	XDR xdrs;
193 	int error;
194 
195 	if (svcaddr == NULL) {
196 		rpc_createerr.cf_stat = RPC_UNKNOWNADDR;
197 		return (NULL);
198 	}
199 
200 	if (!__rpc_socket2sockinfo(so, &si)) {
201 		rpc_createerr.cf_stat = RPC_TLIERROR;
202 		rpc_createerr.cf_error.re_errno = 0;
203 		return (NULL);
204 	}
205 
206 	/*
207 	 * Find the receive and the send size
208 	 */
209 	sendsz = __rpc_get_t_size(si.si_af, si.si_proto, (int)sendsz);
210 	recvsz = __rpc_get_t_size(si.si_af, si.si_proto, (int)recvsz);
211 	if ((sendsz == 0) || (recvsz == 0)) {
212 		rpc_createerr.cf_stat = RPC_TLIERROR; /* XXX */
213 		rpc_createerr.cf_error.re_errno = 0;
214 		return (NULL);
215 	}
216 
217 	cl = mem_alloc(sizeof (CLIENT));
218 
219 	/*
220 	 * Should be multiple of 4 for XDR.
221 	 */
222 	sendsz = ((sendsz + 3) / 4) * 4;
223 	recvsz = ((recvsz + 3) / 4) * 4;
224 	cu = mem_alloc(sizeof (*cu));
225 	cu->cu_threads = 0;
226 	cu->cu_closing = FALSE;
227 	cu->cu_closed = FALSE;
228 	(void) memcpy(&cu->cu_raddr, svcaddr, (size_t)svcaddr->sa_len);
229 	cu->cu_rlen = svcaddr->sa_len;
230 	/* Other values can also be set through clnt_control() */
231 	cu->cu_wait.tv_sec = 3;	/* heuristically chosen */
232 	cu->cu_wait.tv_usec = 0;
233 	cu->cu_total.tv_sec = -1;
234 	cu->cu_total.tv_usec = -1;
235 	cu->cu_sendsz = sendsz;
236 	cu->cu_recvsz = recvsz;
237 	cu->cu_async = FALSE;
238 	cu->cu_connect = FALSE;
239 	cu->cu_connected = FALSE;
240 	cu->cu_waitchan = "rpcrecv";
241 	cu->cu_waitflag = 0;
242 	cu->cu_cwnd = MAXCWND / 2;
243 	cu->cu_sent = 0;
244 	cu->cu_cwnd_wait = FALSE;
245 	(void) getmicrotime(&now);
246 	cu->cu_xid = __RPC_GETXID(&now);
247 	call_msg.rm_xid = cu->cu_xid;
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 	SOCKBUF_LOCK(&so->so_rcv);
274 recheck_socket:
275 	if (sb->sb_upcall) {
276 		if (sb->sb_upcall != clnt_dg_soupcall) {
277 			SOCKBUF_UNLOCK(&so->so_rcv);
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 		SOCKBUF_UNLOCK(&so->so_rcv);
291 		cs = mem_alloc(sizeof(*cs));
292 		SOCKBUF_LOCK(&so->so_rcv);
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 	SOCKBUF_UNLOCK(&so->so_rcv);
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 	if (cl) {
317 		mem_free(cl, sizeof (CLIENT));
318 		if (cu)
319 			mem_free(cu, sizeof (*cu));
320 	}
321 	return (NULL);
322 }
323 
324 static enum clnt_stat
325 clnt_dg_call(
326 	CLIENT		*cl,		/* client handle */
327 	struct rpc_callextra *ext,	/* call metadata */
328 	rpcproc_t	proc,		/* procedure number */
329 	struct mbuf	*args,		/* pointer to args */
330 	struct mbuf	**resultsp,	/* pointer to results */
331 	struct timeval	utimeout)	/* seconds to wait before giving up */
332 {
333 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
334 	struct cu_socket *cs;
335 	struct rpc_timers *rt;
336 	AUTH *auth;
337 	struct rpc_err *errp;
338 	enum clnt_stat stat;
339 	XDR xdrs;
340 	struct rpc_msg reply_msg;
341 	bool_t ok;
342 	int retrans;			/* number of re-transmits so far */
343 	int nrefreshes = 2;		/* number of times to refresh cred */
344 	struct timeval *tvp;
345 	int timeout;
346 	int retransmit_time;
347 	int next_sendtime, starttime, rtt, time_waited, tv = 0;
348 	struct sockaddr *sa;
349 	socklen_t salen;
350 	uint32_t xid = 0;
351 	struct mbuf *mreq = NULL, *results;
352 	struct cu_request *cr;
353 	int error;
354 
355 	cs = cu->cu_socket->so_rcv.sb_upcallarg;
356 	cr = malloc(sizeof(struct cu_request), M_RPC, M_WAITOK);
357 
358 	mtx_lock(&cs->cs_lock);
359 
360 	if (cu->cu_closing || cu->cu_closed) {
361 		mtx_unlock(&cs->cs_lock);
362 		free(cr, M_RPC);
363 		return (RPC_CANTSEND);
364 	}
365 	cu->cu_threads++;
366 
367 	if (ext) {
368 		auth = ext->rc_auth;
369 		errp = &ext->rc_err;
370 	} else {
371 		auth = cl->cl_auth;
372 		errp = &cu->cu_error;
373 	}
374 
375 	cr->cr_client = cl;
376 	cr->cr_mrep = NULL;
377 	cr->cr_error = 0;
378 
379 	if (cu->cu_total.tv_usec == -1) {
380 		tvp = &utimeout; /* use supplied timeout */
381 	} else {
382 		tvp = &cu->cu_total; /* use default timeout */
383 	}
384 	if (tvp->tv_sec || tvp->tv_usec)
385 		timeout = tvtohz(tvp);
386 	else
387 		timeout = 0;
388 
389 	if (cu->cu_connect && !cu->cu_connected) {
390 		mtx_unlock(&cs->cs_lock);
391 		error = soconnect(cu->cu_socket,
392 		    (struct sockaddr *)&cu->cu_raddr, curthread);
393 		mtx_lock(&cs->cs_lock);
394 		if (error) {
395 			errp->re_errno = error;
396 			errp->re_status = stat = RPC_CANTSEND;
397 			goto out;
398 		}
399 		cu->cu_connected = 1;
400 	}
401 	if (cu->cu_connected) {
402 		sa = NULL;
403 		salen = 0;
404 	} else {
405 		sa = (struct sockaddr *)&cu->cu_raddr;
406 		salen = cu->cu_rlen;
407 	}
408 	time_waited = 0;
409 	retrans = 0;
410 	if (ext && ext->rc_timers) {
411 		rt = ext->rc_timers;
412 		if (!rt->rt_rtxcur)
413 			rt->rt_rtxcur = tvtohz(&cu->cu_wait);
414 		retransmit_time = next_sendtime = rt->rt_rtxcur;
415 	} else {
416 		rt = NULL;
417 		retransmit_time = next_sendtime = tvtohz(&cu->cu_wait);
418 	}
419 
420 	starttime = ticks;
421 
422 call_again:
423 	mtx_assert(&cs->cs_lock, MA_OWNED);
424 
425 	cu->cu_xid++;
426 	xid = cu->cu_xid;
427 
428 send_again:
429 	mtx_unlock(&cs->cs_lock);
430 
431 	mreq = m_gethdr(M_WAITOK, MT_DATA);
432 	KASSERT(cu->cu_mcalllen <= MHLEN, ("RPC header too big"));
433 	bcopy(cu->cu_mcallc, mreq->m_data, cu->cu_mcalllen);
434 	mreq->m_len = cu->cu_mcalllen;
435 
436 	/*
437 	 * The XID is the first thing in the request.
438 	 */
439 	*mtod(mreq, uint32_t *) = htonl(xid);
440 
441 	xdrmbuf_create(&xdrs, mreq, XDR_ENCODE);
442 
443 	if (cu->cu_async == TRUE && args == NULL)
444 		goto get_reply;
445 
446 	if ((! XDR_PUTINT32(&xdrs, &proc)) ||
447 	    (! AUTH_MARSHALL(auth, xid, &xdrs,
448 		m_copym(args, 0, M_COPYALL, M_WAITOK)))) {
449 		errp->re_status = stat = RPC_CANTENCODEARGS;
450 		mtx_lock(&cs->cs_lock);
451 		goto out;
452 	}
453 	mreq->m_pkthdr.len = m_length(mreq, NULL);
454 
455 	cr->cr_xid = xid;
456 	mtx_lock(&cs->cs_lock);
457 
458 	/*
459 	 * Try to get a place in the congestion window.
460 	 */
461 	while (cu->cu_sent >= cu->cu_cwnd) {
462 		cu->cu_cwnd_wait = TRUE;
463 		error = msleep(&cu->cu_cwnd_wait, &cs->cs_lock,
464 		    cu->cu_waitflag, "rpccwnd", 0);
465 		if (error) {
466 			errp->re_errno = error;
467 			if (error == EINTR || error == ERESTART)
468 				errp->re_status = stat = RPC_INTR;
469 			else
470 				errp->re_status = stat = RPC_CANTSEND;
471 			goto out;
472 		}
473 	}
474 	cu->cu_sent += CWNDSCALE;
475 
476 	TAILQ_INSERT_TAIL(&cs->cs_pending, cr, cr_link);
477 	mtx_unlock(&cs->cs_lock);
478 
479 	/*
480 	 * sosend consumes mreq.
481 	 */
482 	error = sosend(cu->cu_socket, sa, NULL, mreq, NULL, 0, curthread);
483 	mreq = NULL;
484 
485 	/*
486 	 * sub-optimal code appears here because we have
487 	 * some clock time to spare while the packets are in flight.
488 	 * (We assume that this is actually only executed once.)
489 	 */
490 	reply_msg.acpted_rply.ar_verf.oa_flavor = AUTH_NULL;
491 	reply_msg.acpted_rply.ar_verf.oa_base = cr->cr_verf;
492 	reply_msg.acpted_rply.ar_verf.oa_length = 0;
493 	reply_msg.acpted_rply.ar_results.where = NULL;
494 	reply_msg.acpted_rply.ar_results.proc = (xdrproc_t)xdr_void;
495 
496 	mtx_lock(&cs->cs_lock);
497 	if (error) {
498 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
499 		errp->re_errno = error;
500 		errp->re_status = stat = RPC_CANTSEND;
501 		cu->cu_sent -= CWNDSCALE;
502 		if (cu->cu_cwnd_wait) {
503 			cu->cu_cwnd_wait = FALSE;
504 			wakeup(&cu->cu_cwnd_wait);
505 		}
506 		goto out;
507 	}
508 
509 	/*
510 	 * Check to see if we got an upcall while waiting for the
511 	 * lock.
512 	 */
513 	if (cr->cr_error) {
514 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
515 		errp->re_errno = cr->cr_error;
516 		errp->re_status = stat = RPC_CANTRECV;
517 		cu->cu_sent -= CWNDSCALE;
518 		if (cu->cu_cwnd_wait) {
519 			cu->cu_cwnd_wait = FALSE;
520 			wakeup(&cu->cu_cwnd_wait);
521 		}
522 		goto out;
523 	}
524 	if (cr->cr_mrep) {
525 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
526 		cu->cu_sent -= CWNDSCALE;
527 		if (cu->cu_cwnd_wait) {
528 			cu->cu_cwnd_wait = FALSE;
529 			wakeup(&cu->cu_cwnd_wait);
530 		}
531 		goto got_reply;
532 	}
533 
534 	/*
535 	 * Hack to provide rpc-based message passing
536 	 */
537 	if (timeout == 0) {
538 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
539 		errp->re_status = stat = RPC_TIMEDOUT;
540 		cu->cu_sent -= CWNDSCALE;
541 		if (cu->cu_cwnd_wait) {
542 			cu->cu_cwnd_wait = FALSE;
543 			wakeup(&cu->cu_cwnd_wait);
544 		}
545 		goto out;
546 	}
547 
548 get_reply:
549 	for (;;) {
550 		/* Decide how long to wait. */
551 		if (next_sendtime < timeout)
552 			tv = next_sendtime;
553 		else
554 			tv = timeout;
555 		tv -= time_waited;
556 
557 		if (tv > 0) {
558 			if (cu->cu_closing || cu->cu_closed) {
559 				error = 0;
560 				cr->cr_error = ESHUTDOWN;
561 			} else {
562 				error = msleep(cr, &cs->cs_lock,
563 				    cu->cu_waitflag, cu->cu_waitchan, tv);
564 			}
565 		} else {
566 			error = EWOULDBLOCK;
567 		}
568 
569 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
570 		cu->cu_sent -= CWNDSCALE;
571 		if (cu->cu_cwnd_wait) {
572 			cu->cu_cwnd_wait = FALSE;
573 			wakeup(&cu->cu_cwnd_wait);
574 		}
575 
576 		if (!error) {
577 			/*
578 			 * We were woken up by the upcall.  If the
579 			 * upcall had a receive error, report that,
580 			 * otherwise we have a reply.
581 			 */
582 			if (cr->cr_error) {
583 				errp->re_errno = cr->cr_error;
584 				errp->re_status = stat = RPC_CANTRECV;
585 				goto out;
586 			}
587 
588 			cu->cu_cwnd += (CWNDSCALE * CWNDSCALE
589 			    + cu->cu_cwnd / 2) / cu->cu_cwnd;
590 			if (cu->cu_cwnd > MAXCWND)
591 				cu->cu_cwnd = MAXCWND;
592 
593 			if (rt) {
594 				/*
595 				 * Add one to the time since a tick
596 				 * count of N means that the actual
597 				 * time taken was somewhere between N
598 				 * and N+1.
599 				 */
600 				rtt = ticks - starttime + 1;
601 
602 				/*
603 				 * Update our estimate of the round
604 				 * trip time using roughly the
605 				 * algorithm described in RFC
606 				 * 2988. Given an RTT sample R:
607 				 *
608 				 * RTTVAR = (1-beta) * RTTVAR + beta * |SRTT-R|
609 				 * SRTT = (1-alpha) * SRTT + alpha * R
610 				 *
611 				 * where alpha = 0.125 and beta = 0.25.
612 				 *
613 				 * The initial retransmit timeout is
614 				 * SRTT + 4*RTTVAR and doubles on each
615 				 * retransmision.
616 				 */
617 				if (rt->rt_srtt == 0) {
618 					rt->rt_srtt = rtt;
619 					rt->rt_deviate = rtt / 2;
620 				} else {
621 					int32_t error = rtt - rt->rt_srtt;
622 					rt->rt_srtt += error / 8;
623 					error = abs(error) - rt->rt_deviate;
624 					rt->rt_deviate += error / 4;
625 				}
626 				rt->rt_rtxcur = rt->rt_srtt + 4*rt->rt_deviate;
627 			}
628 
629 			break;
630 		}
631 
632 		/*
633 		 * The sleep returned an error so our request is still
634 		 * on the list. If we got EWOULDBLOCK, we may want to
635 		 * re-send the request.
636 		 */
637 		if (error != EWOULDBLOCK) {
638 			errp->re_errno = error;
639 			if (error == EINTR || error == ERESTART)
640 				errp->re_status = stat = RPC_INTR;
641 			else
642 				errp->re_status = stat = RPC_CANTRECV;
643 			goto out;
644 		}
645 
646 		time_waited = ticks - starttime;
647 
648 		/* Check for timeout. */
649 		if (time_waited > timeout) {
650 			errp->re_errno = EWOULDBLOCK;
651 			errp->re_status = stat = RPC_TIMEDOUT;
652 			goto out;
653 		}
654 
655 		/* Retransmit if necessary. */
656 		if (time_waited >= next_sendtime) {
657 			cu->cu_cwnd /= 2;
658 			if (cu->cu_cwnd < CWNDSCALE)
659 				cu->cu_cwnd = CWNDSCALE;
660 			if (ext && ext->rc_feedback) {
661 				mtx_unlock(&cs->cs_lock);
662 				if (retrans == 0)
663 					ext->rc_feedback(FEEDBACK_REXMIT1,
664 					    proc, ext->rc_feedback_arg);
665 				else
666 					ext->rc_feedback(FEEDBACK_REXMIT2,
667 					    proc, ext->rc_feedback_arg);
668 				mtx_lock(&cs->cs_lock);
669 			}
670 			if (cu->cu_closing || cu->cu_closed) {
671 				errp->re_errno = ESHUTDOWN;
672 				errp->re_status = stat = RPC_CANTRECV;
673 				goto out;
674 			}
675 			retrans++;
676 			/* update retransmit_time */
677 			if (retransmit_time < RPC_MAX_BACKOFF * hz)
678 				retransmit_time = 2 * retransmit_time;
679 			next_sendtime += retransmit_time;
680 			goto send_again;
681 		}
682 		cu->cu_sent += CWNDSCALE;
683 		TAILQ_INSERT_TAIL(&cs->cs_pending, cr, cr_link);
684 	}
685 
686 got_reply:
687 	/*
688 	 * Now decode and validate the response. We need to drop the
689 	 * lock since xdr_replymsg may end up sleeping in malloc.
690 	 */
691 	mtx_unlock(&cs->cs_lock);
692 
693 	if (ext && ext->rc_feedback)
694 		ext->rc_feedback(FEEDBACK_OK, proc, ext->rc_feedback_arg);
695 
696 	xdrmbuf_create(&xdrs, cr->cr_mrep, XDR_DECODE);
697 	ok = xdr_replymsg(&xdrs, &reply_msg);
698 	cr->cr_mrep = NULL;
699 
700 	if (ok) {
701 		if ((reply_msg.rm_reply.rp_stat == MSG_ACCEPTED) &&
702 		    (reply_msg.acpted_rply.ar_stat == SUCCESS))
703 			errp->re_status = stat = RPC_SUCCESS;
704 		else
705 			stat = _seterr_reply(&reply_msg, &(cu->cu_error));
706 
707 		if (errp->re_status == RPC_SUCCESS) {
708 			results = xdrmbuf_getall(&xdrs);
709 			if (! AUTH_VALIDATE(auth, xid,
710 				&reply_msg.acpted_rply.ar_verf,
711 				&results)) {
712 				errp->re_status = stat = RPC_AUTHERROR;
713 				errp->re_why = AUTH_INVALIDRESP;
714 				if (retrans &&
715 				    auth->ah_cred.oa_flavor == RPCSEC_GSS) {
716 					/*
717 					 * If we retransmitted, its
718 					 * possible that we will
719 					 * receive a reply for one of
720 					 * the earlier transmissions
721 					 * (which will use an older
722 					 * RPCSEC_GSS sequence
723 					 * number). In this case, just
724 					 * go back and listen for a
725 					 * new reply. We could keep a
726 					 * record of all the seq
727 					 * numbers we have transmitted
728 					 * so far so that we could
729 					 * accept a reply for any of
730 					 * them here.
731 					 */
732 					XDR_DESTROY(&xdrs);
733 					mtx_lock(&cs->cs_lock);
734 					cu->cu_sent += CWNDSCALE;
735 					TAILQ_INSERT_TAIL(&cs->cs_pending,
736 					    cr, cr_link);
737 					cr->cr_mrep = NULL;
738 					goto get_reply;
739 				}
740 			} else {
741 				*resultsp = results;
742 			}
743 		}		/* end successful completion */
744 		/*
745 		 * If unsuccesful AND error is an authentication error
746 		 * then refresh credentials and try again, else break
747 		 */
748 		else if (stat == RPC_AUTHERROR)
749 			/* maybe our credentials need to be refreshed ... */
750 			if (nrefreshes > 0 &&
751 			    AUTH_REFRESH(auth, &reply_msg)) {
752 				nrefreshes--;
753 				XDR_DESTROY(&xdrs);
754 				mtx_lock(&cs->cs_lock);
755 				goto call_again;
756 			}
757 		/* end of unsuccessful completion */
758 	}	/* end of valid reply message */
759 	else {
760 		errp->re_status = stat = RPC_CANTDECODERES;
761 
762 	}
763 	XDR_DESTROY(&xdrs);
764 	mtx_lock(&cs->cs_lock);
765 out:
766 	mtx_assert(&cs->cs_lock, MA_OWNED);
767 
768 	if (mreq)
769 		m_freem(mreq);
770 	if (cr->cr_mrep)
771 		m_freem(cr->cr_mrep);
772 
773 	cu->cu_threads--;
774 	if (cu->cu_closing)
775 		wakeup(cu);
776 
777 	mtx_unlock(&cs->cs_lock);
778 
779 	if (auth && stat != RPC_SUCCESS)
780 		AUTH_VALIDATE(auth, xid, NULL, NULL);
781 
782 	free(cr, M_RPC);
783 
784 	return (stat);
785 }
786 
787 static void
788 clnt_dg_geterr(CLIENT *cl, struct rpc_err *errp)
789 {
790 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
791 
792 	*errp = cu->cu_error;
793 }
794 
795 static bool_t
796 clnt_dg_freeres(CLIENT *cl, xdrproc_t xdr_res, void *res_ptr)
797 {
798 	XDR xdrs;
799 	bool_t dummy;
800 
801 	xdrs.x_op = XDR_FREE;
802 	dummy = (*xdr_res)(&xdrs, res_ptr);
803 
804 	return (dummy);
805 }
806 
807 /*ARGSUSED*/
808 static void
809 clnt_dg_abort(CLIENT *h)
810 {
811 }
812 
813 static bool_t
814 clnt_dg_control(CLIENT *cl, u_int request, void *info)
815 {
816 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
817 	struct cu_socket *cs;
818 	struct sockaddr *addr;
819 
820 	cs = cu->cu_socket->so_rcv.sb_upcallarg;
821 	mtx_lock(&cs->cs_lock);
822 
823 	switch (request) {
824 	case CLSET_FD_CLOSE:
825 		cu->cu_closeit = TRUE;
826 		mtx_unlock(&cs->cs_lock);
827 		return (TRUE);
828 	case CLSET_FD_NCLOSE:
829 		cu->cu_closeit = FALSE;
830 		mtx_unlock(&cs->cs_lock);
831 		return (TRUE);
832 	}
833 
834 	/* for other requests which use info */
835 	if (info == NULL) {
836 		mtx_unlock(&cs->cs_lock);
837 		return (FALSE);
838 	}
839 	switch (request) {
840 	case CLSET_TIMEOUT:
841 		if (time_not_ok((struct timeval *)info)) {
842 			mtx_unlock(&cs->cs_lock);
843 			return (FALSE);
844 		}
845 		cu->cu_total = *(struct timeval *)info;
846 		break;
847 	case CLGET_TIMEOUT:
848 		*(struct timeval *)info = cu->cu_total;
849 		break;
850 	case CLSET_RETRY_TIMEOUT:
851 		if (time_not_ok((struct timeval *)info)) {
852 			mtx_unlock(&cs->cs_lock);
853 			return (FALSE);
854 		}
855 		cu->cu_wait = *(struct timeval *)info;
856 		break;
857 	case CLGET_RETRY_TIMEOUT:
858 		*(struct timeval *)info = cu->cu_wait;
859 		break;
860 	case CLGET_SVC_ADDR:
861 		/*
862 		 * Slightly different semantics to userland - we use
863 		 * sockaddr instead of netbuf.
864 		 */
865 		memcpy(info, &cu->cu_raddr, cu->cu_raddr.ss_len);
866 		break;
867 	case CLSET_SVC_ADDR:		/* set to new address */
868 		addr = (struct sockaddr *)info;
869 		(void) memcpy(&cu->cu_raddr, addr, addr->sa_len);
870 		break;
871 	case CLGET_XID:
872 		*(uint32_t *)info = cu->cu_xid;
873 		break;
874 
875 	case CLSET_XID:
876 		/* This will set the xid of the NEXT call */
877 		/* decrement by 1 as clnt_dg_call() increments once */
878 		cu->cu_xid = *(uint32_t *)info - 1;
879 		break;
880 
881 	case CLGET_VERS:
882 		/*
883 		 * This RELIES on the information that, in the call body,
884 		 * the version number field is the fifth field from the
885 		 * begining of the RPC header. MUST be changed if the
886 		 * call_struct is changed
887 		 */
888 		*(uint32_t *)info =
889 		    ntohl(*(uint32_t *)(void *)(cu->cu_mcallc +
890 		    4 * BYTES_PER_XDR_UNIT));
891 		break;
892 
893 	case CLSET_VERS:
894 		*(uint32_t *)(void *)(cu->cu_mcallc + 4 * BYTES_PER_XDR_UNIT)
895 			= htonl(*(uint32_t *)info);
896 		break;
897 
898 	case CLGET_PROG:
899 		/*
900 		 * This RELIES on the information that, in the call body,
901 		 * the program number field is the fourth field from the
902 		 * begining of the RPC header. MUST be changed if the
903 		 * call_struct is changed
904 		 */
905 		*(uint32_t *)info =
906 		    ntohl(*(uint32_t *)(void *)(cu->cu_mcallc +
907 		    3 * BYTES_PER_XDR_UNIT));
908 		break;
909 
910 	case CLSET_PROG:
911 		*(uint32_t *)(void *)(cu->cu_mcallc + 3 * BYTES_PER_XDR_UNIT)
912 			= htonl(*(uint32_t *)info);
913 		break;
914 	case CLSET_ASYNC:
915 		cu->cu_async = *(int *)info;
916 		break;
917 	case CLSET_CONNECT:
918 		cu->cu_connect = *(int *)info;
919 		break;
920 	case CLSET_WAITCHAN:
921 		cu->cu_waitchan = (const char *)info;
922 		break;
923 	case CLGET_WAITCHAN:
924 		*(const char **) info = cu->cu_waitchan;
925 		break;
926 	case CLSET_INTERRUPTIBLE:
927 		if (*(int *) info)
928 			cu->cu_waitflag = PCATCH;
929 		else
930 			cu->cu_waitflag = 0;
931 		break;
932 	case CLGET_INTERRUPTIBLE:
933 		if (cu->cu_waitflag)
934 			*(int *) info = TRUE;
935 		else
936 			*(int *) info = FALSE;
937 		break;
938 	default:
939 		mtx_unlock(&cs->cs_lock);
940 		return (FALSE);
941 	}
942 	mtx_unlock(&cs->cs_lock);
943 	return (TRUE);
944 }
945 
946 static void
947 clnt_dg_close(CLIENT *cl)
948 {
949 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
950 	struct cu_socket *cs;
951 	struct cu_request *cr;
952 
953 	cs = cu->cu_socket->so_rcv.sb_upcallarg;
954 	mtx_lock(&cs->cs_lock);
955 
956 	if (cu->cu_closed) {
957 		mtx_unlock(&cs->cs_lock);
958 		return;
959 	}
960 
961 	if (cu->cu_closing) {
962 		while (cu->cu_closing)
963 			msleep(cu, &cs->cs_lock, 0, "rpcclose", 0);
964 		KASSERT(cu->cu_closed, ("client should be closed"));
965 		mtx_unlock(&cs->cs_lock);
966 		return;
967 	}
968 
969 	/*
970 	 * Abort any pending requests and wait until everyone
971 	 * has finished with clnt_vc_call.
972 	 */
973 	cu->cu_closing = TRUE;
974 	TAILQ_FOREACH(cr, &cs->cs_pending, cr_link) {
975 		if (cr->cr_client == cl) {
976 			cr->cr_xid = 0;
977 			cr->cr_error = ESHUTDOWN;
978 			wakeup(cr);
979 		}
980 	}
981 
982 	while (cu->cu_threads)
983 		msleep(cu, &cs->cs_lock, 0, "rpcclose", 0);
984 
985 	cu->cu_closing = FALSE;
986 	cu->cu_closed = TRUE;
987 
988 	mtx_unlock(&cs->cs_lock);
989 	wakeup(cu);
990 }
991 
992 static void
993 clnt_dg_destroy(CLIENT *cl)
994 {
995 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
996 	struct cu_socket *cs;
997 	struct socket *so = NULL;
998 	bool_t lastsocketref;
999 
1000 	cs = cu->cu_socket->so_rcv.sb_upcallarg;
1001 	clnt_dg_close(cl);
1002 
1003 	SOCKBUF_LOCK(&cu->cu_socket->so_rcv);
1004 	mtx_lock(&cs->cs_lock);
1005 
1006 	cs->cs_refs--;
1007 	if (cs->cs_refs == 0) {
1008 		mtx_unlock(&cs->cs_lock);
1009 		soupcall_clear(cu->cu_socket, SO_RCV);
1010 		clnt_dg_upcallsdone(cu->cu_socket, cs);
1011 		SOCKBUF_UNLOCK(&cu->cu_socket->so_rcv);
1012 		mtx_destroy(&cs->cs_lock);
1013 		mem_free(cs, sizeof(*cs));
1014 		lastsocketref = TRUE;
1015 	} else {
1016 		mtx_unlock(&cs->cs_lock);
1017 		SOCKBUF_UNLOCK(&cu->cu_socket->so_rcv);
1018 		lastsocketref = FALSE;
1019 	}
1020 
1021 	if (cu->cu_closeit && lastsocketref) {
1022 		so = cu->cu_socket;
1023 		cu->cu_socket = NULL;
1024 	}
1025 
1026 	if (so)
1027 		soclose(so);
1028 
1029 	if (cl->cl_netid && cl->cl_netid[0])
1030 		mem_free(cl->cl_netid, strlen(cl->cl_netid) +1);
1031 	if (cl->cl_tp && cl->cl_tp[0])
1032 		mem_free(cl->cl_tp, strlen(cl->cl_tp) +1);
1033 	mem_free(cu, sizeof (*cu));
1034 	mem_free(cl, sizeof (CLIENT));
1035 }
1036 
1037 /*
1038  * Make sure that the time is not garbage.  -1 value is allowed.
1039  */
1040 static bool_t
1041 time_not_ok(struct timeval *t)
1042 {
1043 	return (t->tv_sec < -1 || t->tv_sec > 100000000 ||
1044 		t->tv_usec < -1 || t->tv_usec > 1000000);
1045 }
1046 
1047 int
1048 clnt_dg_soupcall(struct socket *so, void *arg, int waitflag)
1049 {
1050 	struct cu_socket *cs = (struct cu_socket *) arg;
1051 	struct uio uio;
1052 	struct mbuf *m;
1053 	struct mbuf *control;
1054 	struct cu_request *cr;
1055 	int error, rcvflag, foundreq;
1056 	uint32_t xid;
1057 
1058 	cs->cs_upcallrefs++;
1059 	uio.uio_resid = 1000000000;
1060 	uio.uio_td = curthread;
1061 	do {
1062 		SOCKBUF_UNLOCK(&so->so_rcv);
1063 		m = NULL;
1064 		control = NULL;
1065 		rcvflag = MSG_DONTWAIT;
1066 		error = soreceive(so, NULL, &uio, &m, &control, &rcvflag);
1067 		if (control)
1068 			m_freem(control);
1069 		SOCKBUF_LOCK(&so->so_rcv);
1070 
1071 		if (error == EWOULDBLOCK)
1072 			break;
1073 
1074 		/*
1075 		 * If there was an error, wake up all pending
1076 		 * requests.
1077 		 */
1078 		if (error) {
1079 			mtx_lock(&cs->cs_lock);
1080 			TAILQ_FOREACH(cr, &cs->cs_pending, cr_link) {
1081 				cr->cr_xid = 0;
1082 				cr->cr_error = error;
1083 				wakeup(cr);
1084 			}
1085 			mtx_unlock(&cs->cs_lock);
1086 			break;
1087 		}
1088 
1089 		/*
1090 		 * The XID is in the first uint32_t of the reply.
1091 		 */
1092 		if (m->m_len < sizeof(xid) && m_length(m, NULL) < sizeof(xid)) {
1093 			/*
1094 			 * Should never happen.
1095 			 */
1096 			m_freem(m);
1097 			continue;
1098 		}
1099 
1100 		m_copydata(m, 0, sizeof(xid), (char *)&xid);
1101 		xid = ntohl(xid);
1102 
1103 		/*
1104 		 * Attempt to match this reply with a pending request.
1105 		 */
1106 		mtx_lock(&cs->cs_lock);
1107 		foundreq = 0;
1108 		TAILQ_FOREACH(cr, &cs->cs_pending, cr_link) {
1109 			if (cr->cr_xid == xid) {
1110 				/*
1111 				 * This one matches. We leave the
1112 				 * reply mbuf in cr->cr_mrep. Set the
1113 				 * XID to zero so that we will ignore
1114 				 * any duplicated replies that arrive
1115 				 * before clnt_dg_call removes it from
1116 				 * the queue.
1117 				 */
1118 				cr->cr_xid = 0;
1119 				cr->cr_mrep = m;
1120 				cr->cr_error = 0;
1121 				foundreq = 1;
1122 				wakeup(cr);
1123 				break;
1124 			}
1125 		}
1126 		mtx_unlock(&cs->cs_lock);
1127 
1128 		/*
1129 		 * If we didn't find the matching request, just drop
1130 		 * it - its probably a repeated reply.
1131 		 */
1132 		if (!foundreq)
1133 			m_freem(m);
1134 	} while (m);
1135 	cs->cs_upcallrefs--;
1136 	if (cs->cs_upcallrefs < 0)
1137 		panic("rpcdg upcall refcnt");
1138 	if (cs->cs_upcallrefs == 0)
1139 		wakeup(&cs->cs_upcallrefs);
1140 	return (SU_OK);
1141 }
1142 
1143 /*
1144  * Wait for all upcalls in progress to complete.
1145  */
1146 static void
1147 clnt_dg_upcallsdone(struct socket *so, struct cu_socket *cs)
1148 {
1149 
1150 	SOCKBUF_LOCK_ASSERT(&so->so_rcv);
1151 
1152 	while (cs->cs_upcallrefs > 0)
1153 		(void) msleep(&cs->cs_upcallrefs, SOCKBUF_MTX(&so->so_rcv), 0,
1154 		    "rpcdgup", 0);
1155 }
1156