xref: /illumos-gate/usr/src/uts/common/rpc/svc_clts.c (revision e088a04aae44e543fb280588d641fedad555dd6b)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  *  Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
23  *  Use is subject to license terms.
24  */
25 
26 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
27 /*	  All Rights Reserved  	*/
28 
29 /*
30  * Portions of this source code were derived from Berkeley 4.3 BSD
31  * under license from the Regents of the University of California.
32  */
33 
34 /*
35  * svc_clts.c
36  * Server side for RPC in the kernel.
37  *
38  */
39 
40 #include <sys/param.h>
41 #include <sys/types.h>
42 #include <sys/sysmacros.h>
43 #include <sys/file.h>
44 #include <sys/stream.h>
45 #include <sys/strsubr.h>
46 #include <sys/tihdr.h>
47 #include <sys/tiuser.h>
48 #include <sys/t_kuser.h>
49 #include <sys/fcntl.h>
50 #include <sys/errno.h>
51 #include <sys/kmem.h>
52 #include <sys/systm.h>
53 #include <sys/cmn_err.h>
54 #include <sys/kstat.h>
55 #include <sys/vtrace.h>
56 #include <sys/debug.h>
57 
58 #include <rpc/types.h>
59 #include <rpc/xdr.h>
60 #include <rpc/auth.h>
61 #include <rpc/clnt.h>
62 #include <rpc/rpc_msg.h>
63 #include <rpc/svc.h>
64 #include <inet/ip.h>
65 
66 /*
67  * Routines exported through ops vector.
68  */
69 static bool_t		svc_clts_krecv(SVCXPRT *, mblk_t *, struct rpc_msg *);
70 static bool_t		svc_clts_ksend(SVCXPRT *, struct rpc_msg *);
71 static bool_t		svc_clts_kgetargs(SVCXPRT *, xdrproc_t, caddr_t);
72 static bool_t		svc_clts_kfreeargs(SVCXPRT *, xdrproc_t, caddr_t);
73 static void		svc_clts_kdestroy(SVCMASTERXPRT *);
74 static int		svc_clts_kdup(struct svc_req *, caddr_t, int,
75 				struct dupreq **, bool_t *);
76 static void		svc_clts_kdupdone(struct dupreq *, caddr_t,
77 				void (*)(), int, int);
78 static int32_t		*svc_clts_kgetres(SVCXPRT *, int);
79 static void		svc_clts_kclone_destroy(SVCXPRT *);
80 static void		svc_clts_kfreeres(SVCXPRT *);
81 static void		svc_clts_kstart(SVCMASTERXPRT *);
82 static void		svc_clts_kclone_xprt(SVCXPRT *, SVCXPRT *);
83 
84 /*
85  * Server transport operations vector.
86  */
87 struct svc_ops svc_clts_op = {
88 	svc_clts_krecv,		/* Get requests */
89 	svc_clts_kgetargs,	/* Deserialize arguments */
90 	svc_clts_ksend,		/* Send reply */
91 	svc_clts_kfreeargs,	/* Free argument data space */
92 	svc_clts_kdestroy,	/* Destroy transport handle */
93 	svc_clts_kdup,		/* Check entry in dup req cache */
94 	svc_clts_kdupdone,	/* Mark entry in dup req cache as done */
95 	svc_clts_kgetres,	/* Get pointer to response buffer */
96 	svc_clts_kfreeres,	/* Destroy pre-serialized response header */
97 	svc_clts_kclone_destroy, /* Destroy a clone xprt */
98 	svc_clts_kstart,	/* Tell `ready-to-receive' to rpcmod */
99 	svc_clts_kclone_xprt	/* transport specific clone xprt function */
100 };
101 
102 /*
103  * Transport private data.
104  * Kept in xprt->xp_p2buf.
105  */
106 struct udp_data {
107 	mblk_t	*ud_resp;			/* buffer for response */
108 	mblk_t	*ud_inmp;			/* mblk chain of request */
109 };
110 
111 #define	UD_MAXSIZE	8800
112 #define	UD_INITSIZE	2048
113 
114 /*
115  * Connectionless server statistics
116  */
117 static const struct rpc_clts_server {
118 	kstat_named_t	rscalls;
119 	kstat_named_t	rsbadcalls;
120 	kstat_named_t	rsnullrecv;
121 	kstat_named_t	rsbadlen;
122 	kstat_named_t	rsxdrcall;
123 	kstat_named_t	rsdupchecks;
124 	kstat_named_t	rsdupreqs;
125 } clts_rsstat_tmpl = {
126 	{ "calls",	KSTAT_DATA_UINT64 },
127 	{ "badcalls",	KSTAT_DATA_UINT64 },
128 	{ "nullrecv",	KSTAT_DATA_UINT64 },
129 	{ "badlen",	KSTAT_DATA_UINT64 },
130 	{ "xdrcall",	KSTAT_DATA_UINT64 },
131 	{ "dupchecks",	KSTAT_DATA_UINT64 },
132 	{ "dupreqs",	KSTAT_DATA_UINT64 }
133 };
134 
135 static uint_t clts_rsstat_ndata =
136 	sizeof (clts_rsstat_tmpl) / sizeof (kstat_named_t);
137 
138 #define	CLONE2STATS(clone_xprt)	\
139 	(struct rpc_clts_server *)(clone_xprt)->xp_master->xp_p2
140 
141 #define	RSSTAT_INCR(stats, x)	\
142 	atomic_add_64(&(stats)->x.value.ui64, 1)
143 
144 /*
145  * Create a transport record.
146  * The transport record, output buffer, and private data structure
147  * are allocated.  The output buffer is serialized into using xdrmem.
148  * There is one transport record per user process which implements a
149  * set of services.
150  */
151 /* ARGSUSED */
152 int
153 svc_clts_kcreate(file_t *fp, uint_t sendsz, struct T_info_ack *tinfo,
154     SVCMASTERXPRT **nxprt)
155 {
156 	SVCMASTERXPRT *xprt;
157 	struct rpcstat *rpcstat;
158 
159 	if (nxprt == NULL)
160 		return (EINVAL);
161 
162 	rpcstat = zone_getspecific(rpcstat_zone_key, curproc->p_zone);
163 	ASSERT(rpcstat != NULL);
164 
165 	xprt = kmem_zalloc(sizeof (*xprt), KM_SLEEP);
166 	xprt->xp_lcladdr.buf = kmem_zalloc(sizeof (sin6_t), KM_SLEEP);
167 	xprt->xp_p2 = (caddr_t)rpcstat->rpc_clts_server;
168 	xprt->xp_ops = &svc_clts_op;
169 	xprt->xp_msg_size = tinfo->TSDU_size;
170 
171 	xprt->xp_rtaddr.buf = NULL;
172 	xprt->xp_rtaddr.maxlen = tinfo->ADDR_size;
173 	xprt->xp_rtaddr.len = 0;
174 
175 	*nxprt = xprt;
176 
177 	return (0);
178 }
179 
180 /*
181  * Destroy a transport record.
182  * Frees the space allocated for a transport record.
183  */
184 static void
185 svc_clts_kdestroy(SVCMASTERXPRT *xprt)
186 {
187 	if (xprt->xp_netid)
188 		kmem_free(xprt->xp_netid, strlen(xprt->xp_netid) + 1);
189 	if (xprt->xp_addrmask.maxlen)
190 		kmem_free(xprt->xp_addrmask.buf, xprt->xp_addrmask.maxlen);
191 
192 	mutex_destroy(&xprt->xp_req_lock);
193 	mutex_destroy(&xprt->xp_thread_lock);
194 
195 	kmem_free(xprt->xp_lcladdr.buf, sizeof (sin6_t));
196 	kmem_free(xprt, sizeof (SVCMASTERXPRT));
197 }
198 
199 /*
200  * Transport-type specific part of svc_xprt_cleanup().
201  * Frees the message buffer space allocated for a clone of a transport record
202  */
203 static void
204 svc_clts_kclone_destroy(SVCXPRT *clone_xprt)
205 {
206 	/* LINTED pointer alignment */
207 	struct udp_data *ud = (struct udp_data *)clone_xprt->xp_p2buf;
208 
209 	if (ud->ud_resp) {
210 		/*
211 		 * There should not be any left over results buffer.
212 		 */
213 		ASSERT(ud->ud_resp->b_cont == NULL);
214 
215 		/*
216 		 * Free the T_UNITDATA_{REQ/IND} that svc_clts_krecv
217 		 * saved.
218 		 */
219 		freeb(ud->ud_resp);
220 	}
221 	if (ud->ud_inmp)
222 		freemsg(ud->ud_inmp);
223 }
224 
225 /*
226  * svc_tli_kcreate() calls this function at the end to tell
227  * rpcmod that the transport is ready to receive requests.
228  */
229 /* ARGSUSED */
230 static void
231 svc_clts_kstart(SVCMASTERXPRT *xprt)
232 {
233 }
234 
235 static void
236 svc_clts_kclone_xprt(SVCXPRT *src_xprt, SVCXPRT *dst_xprt)
237 {
238 	struct udp_data *ud_src =
239 	    (struct udp_data *)src_xprt->xp_p2buf;
240 	struct udp_data *ud_dst =
241 	    (struct udp_data *)dst_xprt->xp_p2buf;
242 
243 	if (ud_src->ud_resp)
244 		ud_dst->ud_resp = dupb(ud_src->ud_resp);
245 
246 }
247 
248 
249 /*
250  * Receive rpc requests.
251  * Pulls a request in off the socket, checks if the packet is intact,
252  * and deserializes the call packet.
253  */
254 static bool_t
255 svc_clts_krecv(SVCXPRT *clone_xprt, mblk_t *mp, struct rpc_msg *msg)
256 {
257 	/* LINTED pointer alignment */
258 	struct udp_data *ud = (struct udp_data *)clone_xprt->xp_p2buf;
259 	XDR *xdrs = &clone_xprt->xp_xdrin;
260 	struct rpc_clts_server *stats = CLONE2STATS(clone_xprt);
261 	union T_primitives *pptr;
262 	int hdrsz;
263 	cred_t *cr;
264 
265 	TRACE_0(TR_FAC_KRPC, TR_SVC_CLTS_KRECV_START,
266 	    "svc_clts_krecv_start:");
267 
268 	RSSTAT_INCR(stats, rscalls);
269 
270 	/*
271 	 * The incoming request should start with an M_PROTO message.
272 	 */
273 	if (mp->b_datap->db_type != M_PROTO) {
274 		goto bad;
275 	}
276 
277 	/*
278 	 * The incoming request should be an T_UNITDTA_IND.  There
279 	 * might be other messages coming up the stream, but we can
280 	 * ignore them.
281 	 */
282 	pptr = (union T_primitives *)mp->b_rptr;
283 	if (pptr->type != T_UNITDATA_IND) {
284 		goto bad;
285 	}
286 	/*
287 	 * Do some checking to make sure that the header at least looks okay.
288 	 */
289 	hdrsz = (int)(mp->b_wptr - mp->b_rptr);
290 	if (hdrsz < TUNITDATAINDSZ ||
291 	    hdrsz < (pptr->unitdata_ind.OPT_offset +
292 	    pptr->unitdata_ind.OPT_length) ||
293 	    hdrsz < (pptr->unitdata_ind.SRC_offset +
294 	    pptr->unitdata_ind.SRC_length)) {
295 		goto bad;
296 	}
297 
298 	/*
299 	 * Make sure that the transport provided a usable address.
300 	 */
301 	if (pptr->unitdata_ind.SRC_length <= 0) {
302 		goto bad;
303 	}
304 	/*
305 	 * Point the remote transport address in the service_transport
306 	 * handle at the address in the request.
307 	 */
308 	clone_xprt->xp_rtaddr.buf = (char *)mp->b_rptr +
309 	    pptr->unitdata_ind.SRC_offset;
310 	clone_xprt->xp_rtaddr.len = pptr->unitdata_ind.SRC_length;
311 
312 	/*
313 	 * Copy the local transport address in the service_transport
314 	 * handle at the address in the request. We will have only
315 	 * the local IP address in options.
316 	 */
317 	if (pptr->unitdata_ind.OPT_length && pptr->unitdata_ind.OPT_offset) {
318 		char *dstopt = (char *)mp->b_rptr +
319 		    pptr->unitdata_ind.OPT_offset;
320 		struct T_opthdr *toh = (struct T_opthdr *)dstopt;
321 
322 		if (toh->level == IPPROTO_IPV6 && toh->status == 0 &&
323 		    toh->name == IPV6_PKTINFO) {
324 			struct in6_pktinfo *pkti;
325 
326 			dstopt += sizeof (struct T_opthdr);
327 			pkti = (struct in6_pktinfo *)dstopt;
328 			((sin6_t *)(clone_xprt->xp_lcladdr.buf))->sin6_addr
329 			    = pkti->ipi6_addr;
330 		} else if (toh->level == IPPROTO_IP && toh->status == 0 &&
331 		    toh->name == IP_RECVDSTADDR) {
332 			dstopt += sizeof (struct T_opthdr);
333 			((sin_t *)(clone_xprt->xp_lcladdr.buf))->sin_addr
334 			    = *(struct in_addr *)dstopt;
335 		}
336 	}
337 
338 	/*
339 	 * Save the first mblk which contains the T_unidata_ind in
340 	 * ud_resp.  It will be used to generate the T_unitdata_req
341 	 * during the reply.
342 	 * We reuse any options in the T_unitdata_ind for the T_unitdata_req
343 	 * since we must pass any SCM_UCRED across in order for TX to
344 	 * work. We also make sure any cred_t is carried across.
345 	 */
346 	if (ud->ud_resp) {
347 		if (ud->ud_resp->b_cont != NULL) {
348 			cmn_err(CE_WARN, "svc_clts_krecv: ud_resp %p, "
349 			    "b_cont %p", (void *)ud->ud_resp,
350 			    (void *)ud->ud_resp->b_cont);
351 		}
352 		freeb(ud->ud_resp);
353 	}
354 	/* Move any cred_t to the first mblk in the message */
355 	cr = msg_getcred(mp, NULL);
356 	if (cr != NULL)
357 		mblk_setcred(mp, cr, NOPID);
358 
359 	ud->ud_resp = mp;
360 	mp = mp->b_cont;
361 	ud->ud_resp->b_cont = NULL;
362 
363 	xdrmblk_init(xdrs, mp, XDR_DECODE, 0);
364 
365 	TRACE_0(TR_FAC_KRPC, TR_XDR_CALLMSG_START,
366 	    "xdr_callmsg_start:");
367 	if (! xdr_callmsg(xdrs, msg)) {
368 		TRACE_1(TR_FAC_KRPC, TR_XDR_CALLMSG_END,
369 		    "xdr_callmsg_end:(%S)", "bad");
370 		RSSTAT_INCR(stats, rsxdrcall);
371 		goto bad;
372 	}
373 	TRACE_1(TR_FAC_KRPC, TR_XDR_CALLMSG_END,
374 	    "xdr_callmsg_end:(%S)", "good");
375 
376 	clone_xprt->xp_xid = msg->rm_xid;
377 	ud->ud_inmp = mp;
378 
379 	TRACE_1(TR_FAC_KRPC, TR_SVC_CLTS_KRECV_END,
380 	    "svc_clts_krecv_end:(%S)", "good");
381 	return (TRUE);
382 
383 bad:
384 	if (mp)
385 		freemsg(mp);
386 	if (ud->ud_resp) {
387 		/*
388 		 * There should not be any left over results buffer.
389 		 */
390 		ASSERT(ud->ud_resp->b_cont == NULL);
391 		freeb(ud->ud_resp);
392 		ud->ud_resp = NULL;
393 	}
394 
395 	RSSTAT_INCR(stats, rsbadcalls);
396 	TRACE_1(TR_FAC_KRPC, TR_SVC_CLTS_KRECV_END,
397 	    "svc_clts_krecv_end:(%S)", "bad");
398 	return (FALSE);
399 }
400 
401 /*
402  * Send rpc reply.
403  * Serialize the reply packet into the output buffer then
404  * call t_ksndudata to send it.
405  */
406 static bool_t
407 svc_clts_ksend(SVCXPRT *clone_xprt, struct rpc_msg *msg)
408 {
409 	/* LINTED pointer alignment */
410 	struct udp_data *ud = (struct udp_data *)clone_xprt->xp_p2buf;
411 	XDR *xdrs = &clone_xprt->xp_xdrout;
412 	int stat = FALSE;
413 	mblk_t *mp;
414 	int msgsz;
415 	struct T_unitdata_req *udreq;
416 	xdrproc_t xdr_results;
417 	caddr_t xdr_location;
418 	bool_t has_args;
419 
420 	TRACE_0(TR_FAC_KRPC, TR_SVC_CLTS_KSEND_START,
421 	    "svc_clts_ksend_start:");
422 
423 	ASSERT(ud->ud_resp != NULL);
424 
425 	/*
426 	 * If there is a result procedure specified in the reply message,
427 	 * it will be processed in the xdr_replymsg and SVCAUTH_WRAP.
428 	 * We need to make sure it won't be processed twice, so we null
429 	 * it for xdr_replymsg here.
430 	 */
431 	has_args = FALSE;
432 	if (msg->rm_reply.rp_stat == MSG_ACCEPTED &&
433 	    msg->rm_reply.rp_acpt.ar_stat == SUCCESS) {
434 		if ((xdr_results = msg->acpted_rply.ar_results.proc) != NULL) {
435 			has_args = TRUE;
436 			xdr_location = msg->acpted_rply.ar_results.where;
437 			msg->acpted_rply.ar_results.proc = xdr_void;
438 			msg->acpted_rply.ar_results.where = NULL;
439 		}
440 	}
441 
442 	if (ud->ud_resp->b_cont == NULL) {
443 		/*
444 		 * Allocate an initial mblk for the response data.
445 		 */
446 		while ((mp = allocb(UD_INITSIZE, BPRI_LO)) == NULL) {
447 			if (strwaitbuf(UD_INITSIZE, BPRI_LO)) {
448 				TRACE_1(TR_FAC_KRPC, TR_SVC_CLTS_KSEND_END,
449 				    "svc_clts_ksend_end:(%S)", "strwaitbuf");
450 				return (FALSE);
451 			}
452 		}
453 
454 		/*
455 		 * Initialize the XDR decode stream.  Additional mblks
456 		 * will be allocated if necessary.  They will be UD_MAXSIZE
457 		 * sized.
458 		 */
459 		xdrmblk_init(xdrs, mp, XDR_ENCODE, UD_MAXSIZE);
460 
461 		/*
462 		 * Leave some space for protocol headers.
463 		 */
464 		(void) XDR_SETPOS(xdrs, 512);
465 		mp->b_rptr += 512;
466 
467 		msg->rm_xid = clone_xprt->xp_xid;
468 
469 		ud->ud_resp->b_cont = mp;
470 
471 		TRACE_0(TR_FAC_KRPC, TR_XDR_REPLYMSG_START,
472 		    "xdr_replymsg_start:");
473 		if (!(xdr_replymsg(xdrs, msg) &&
474 		    (!has_args || SVCAUTH_WRAP(&clone_xprt->xp_auth, xdrs,
475 		    xdr_results, xdr_location)))) {
476 			TRACE_1(TR_FAC_KRPC, TR_XDR_REPLYMSG_END,
477 			    "xdr_replymsg_end:(%S)", "bad");
478 			RPCLOG0(1, "xdr_replymsg/SVCAUTH_WRAP failed\n");
479 			goto out;
480 		}
481 		TRACE_1(TR_FAC_KRPC, TR_XDR_REPLYMSG_END,
482 		    "xdr_replymsg_end:(%S)", "good");
483 
484 	} else if (!(xdr_replymsg_body(xdrs, msg) &&
485 	    (!has_args || SVCAUTH_WRAP(&clone_xprt->xp_auth, xdrs,
486 	    xdr_results, xdr_location)))) {
487 		RPCLOG0(1, "xdr_replymsg_body/SVCAUTH_WRAP failed\n");
488 		goto out;
489 	}
490 
491 	msgsz = (int)xmsgsize(ud->ud_resp->b_cont);
492 
493 	if (msgsz <= 0 || (clone_xprt->xp_msg_size != -1 &&
494 	    msgsz > clone_xprt->xp_msg_size)) {
495 #ifdef	DEBUG
496 		cmn_err(CE_NOTE,
497 "KRPC: server response message of %d bytes; transport limits are [0, %d]",
498 		    msgsz, clone_xprt->xp_msg_size);
499 #endif
500 		goto out;
501 	}
502 
503 	/*
504 	 * Construct the T_unitdata_req.  We take advantage
505 	 * of the fact that T_unitdata_ind looks just like
506 	 * T_unitdata_req, except for the primitive type.
507 	 * Reusing it means we preserve any options, and we must preserve
508 	 * the SCM_UCRED option for TX to work.
509 	 * This has the side effect of also passing certain receive-side
510 	 * options like IP_RECVDSTADDR back down the send side. This
511 	 * implies that we can not ASSERT on a non-NULL db_credp when
512 	 * we have send-side options in UDP.
513 	 */
514 	udreq = (struct T_unitdata_req *)ud->ud_resp->b_rptr;
515 	udreq->PRIM_type = T_UNITDATA_REQ;
516 	put(clone_xprt->xp_wq, ud->ud_resp);
517 	stat = TRUE;
518 	ud->ud_resp = NULL;
519 
520 out:
521 	if (stat == FALSE) {
522 		freemsg(ud->ud_resp);
523 		ud->ud_resp = NULL;
524 	}
525 
526 	/*
527 	 * This is completely disgusting.  If public is set it is
528 	 * a pointer to a structure whose first field is the address
529 	 * of the function to free that structure and any related
530 	 * stuff.  (see rrokfree in nfs_xdr.c).
531 	 */
532 	if (xdrs->x_public) {
533 		/* LINTED pointer alignment */
534 		(**((int (**)())xdrs->x_public))(xdrs->x_public);
535 	}
536 
537 	TRACE_1(TR_FAC_KRPC, TR_SVC_CLTS_KSEND_END,
538 	    "svc_clts_ksend_end:(%S)", "done");
539 	return (stat);
540 }
541 
542 /*
543  * Deserialize arguments.
544  */
545 static bool_t
546 svc_clts_kgetargs(SVCXPRT *clone_xprt, xdrproc_t xdr_args,
547     caddr_t args_ptr)
548 {
549 
550 	/* LINTED pointer alignment */
551 	return (SVCAUTH_UNWRAP(&clone_xprt->xp_auth, &clone_xprt->xp_xdrin,
552 	    xdr_args, args_ptr));
553 
554 }
555 
556 static bool_t
557 svc_clts_kfreeargs(SVCXPRT *clone_xprt, xdrproc_t xdr_args,
558     caddr_t args_ptr)
559 {
560 	/* LINTED pointer alignment */
561 	struct udp_data *ud = (struct udp_data *)clone_xprt->xp_p2buf;
562 	XDR *xdrs = &clone_xprt->xp_xdrin;
563 	bool_t retval;
564 
565 	if (args_ptr) {
566 		xdrs->x_op = XDR_FREE;
567 		retval = (*xdr_args)(xdrs, args_ptr);
568 	} else
569 		retval = TRUE;
570 
571 	if (ud->ud_inmp) {
572 		freemsg(ud->ud_inmp);
573 		ud->ud_inmp = NULL;
574 	}
575 
576 	return (retval);
577 }
578 
579 static int32_t *
580 svc_clts_kgetres(SVCXPRT *clone_xprt, int size)
581 {
582 	/* LINTED pointer alignment */
583 	struct udp_data *ud = (struct udp_data *)clone_xprt->xp_p2buf;
584 	XDR *xdrs = &clone_xprt->xp_xdrout;
585 	mblk_t *mp;
586 	int32_t *buf;
587 	struct rpc_msg rply;
588 
589 	/*
590 	 * Allocate an initial mblk for the response data.
591 	 */
592 	while ((mp = allocb(UD_INITSIZE, BPRI_LO)) == NULL) {
593 		if (strwaitbuf(UD_INITSIZE, BPRI_LO)) {
594 			return (FALSE);
595 		}
596 	}
597 
598 	mp->b_cont = NULL;
599 
600 	/*
601 	 * Initialize the XDR decode stream.  Additional mblks
602 	 * will be allocated if necessary.  They will be UD_MAXSIZE
603 	 * sized.
604 	 */
605 	xdrmblk_init(xdrs, mp, XDR_ENCODE, UD_MAXSIZE);
606 
607 	/*
608 	 * Leave some space for protocol headers.
609 	 */
610 	(void) XDR_SETPOS(xdrs, 512);
611 	mp->b_rptr += 512;
612 
613 	/*
614 	 * Assume a successful RPC since most of them are.
615 	 */
616 	rply.rm_xid = clone_xprt->xp_xid;
617 	rply.rm_direction = REPLY;
618 	rply.rm_reply.rp_stat = MSG_ACCEPTED;
619 	rply.acpted_rply.ar_verf = clone_xprt->xp_verf;
620 	rply.acpted_rply.ar_stat = SUCCESS;
621 
622 	if (!xdr_replymsg_hdr(xdrs, &rply)) {
623 		freeb(mp);
624 		return (NULL);
625 	}
626 
627 	buf = XDR_INLINE(xdrs, size);
628 
629 	if (buf == NULL)
630 		freeb(mp);
631 	else
632 		ud->ud_resp->b_cont = mp;
633 
634 	return (buf);
635 }
636 
637 static void
638 svc_clts_kfreeres(SVCXPRT *clone_xprt)
639 {
640 	/* LINTED pointer alignment */
641 	struct udp_data *ud = (struct udp_data *)clone_xprt->xp_p2buf;
642 
643 	if (ud->ud_resp == NULL || ud->ud_resp->b_cont == NULL)
644 		return;
645 
646 	/*
647 	 * SVC_FREERES() is called whenever the server decides not to
648 	 * send normal reply. Thus, we expect only one mblk to be allocated,
649 	 * because we have not attempted any XDR encoding.
650 	 * If we do any XDR encoding and we get an error, then SVC_REPLY()
651 	 * will freemsg(ud->ud_resp);
652 	 */
653 	ASSERT(ud->ud_resp->b_cont->b_cont == NULL);
654 	freeb(ud->ud_resp->b_cont);
655 	ud->ud_resp->b_cont = NULL;
656 }
657 
658 /*
659  * the dup cacheing routines below provide a cache of non-failure
660  * transaction id's.  rpc service routines can use this to detect
661  * retransmissions and re-send a non-failure response.
662  */
663 
664 /*
665  * MAXDUPREQS is the number of cached items.  It should be adjusted
666  * to the service load so that there is likely to be a response entry
667  * when the first retransmission comes in.
668  */
669 #define	MAXDUPREQS	1024
670 
671 /*
672  * This should be appropriately scaled to MAXDUPREQS.
673  */
674 #define	DRHASHSZ	257
675 
676 #if ((DRHASHSZ & (DRHASHSZ - 1)) == 0)
677 #define	XIDHASH(xid)	((xid) & (DRHASHSZ - 1))
678 #else
679 #define	XIDHASH(xid)	((xid) % DRHASHSZ)
680 #endif
681 #define	DRHASH(dr)	XIDHASH((dr)->dr_xid)
682 #define	REQTOXID(req)	((req)->rq_xprt->xp_xid)
683 
684 static int	ndupreqs = 0;
685 int	maxdupreqs = MAXDUPREQS;
686 static kmutex_t dupreq_lock;
687 static struct dupreq *drhashtbl[DRHASHSZ];
688 static int	drhashstat[DRHASHSZ];
689 
690 static void unhash(struct dupreq *);
691 
692 /*
693  * drmru points to the head of a circular linked list in lru order.
694  * drmru->dr_next == drlru
695  */
696 struct dupreq *drmru;
697 
698 /*
699  * PSARC 2003/523 Contract Private Interface
700  * svc_clts_kdup
701  * Changes must be reviewed by Solaris File Sharing
702  * Changes must be communicated to contract-2003-523@sun.com
703  *
704  * svc_clts_kdup searches the request cache and returns 0 if the
705  * request is not found in the cache.  If it is found, then it
706  * returns the state of the request (in progress or done) and
707  * the status or attributes that were part of the original reply.
708  *
709  * If DUP_DONE (there is a duplicate) svc_clts_kdup copies over the
710  * value of the response. In that case, also return in *dupcachedp
711  * whether the response free routine is cached in the dupreq - in which case
712  * the caller should not be freeing it, because it will be done later
713  * in the svc_clts_kdup code when the dupreq is reused.
714  */
715 static int
716 svc_clts_kdup(struct svc_req *req, caddr_t res, int size, struct dupreq **drpp,
717 	bool_t *dupcachedp)
718 {
719 	struct rpc_clts_server *stats = CLONE2STATS(req->rq_xprt);
720 	struct dupreq *dr;
721 	uint32_t xid;
722 	uint32_t drhash;
723 	int status;
724 
725 	xid = REQTOXID(req);
726 	mutex_enter(&dupreq_lock);
727 	RSSTAT_INCR(stats, rsdupchecks);
728 	/*
729 	 * Check to see whether an entry already exists in the cache.
730 	 */
731 	dr = drhashtbl[XIDHASH(xid)];
732 	while (dr != NULL) {
733 		if (dr->dr_xid == xid &&
734 		    dr->dr_proc == req->rq_proc &&
735 		    dr->dr_prog == req->rq_prog &&
736 		    dr->dr_vers == req->rq_vers &&
737 		    dr->dr_addr.len == req->rq_xprt->xp_rtaddr.len &&
738 		    bcmp(dr->dr_addr.buf, req->rq_xprt->xp_rtaddr.buf,
739 		    dr->dr_addr.len) == 0) {
740 			status = dr->dr_status;
741 			if (status == DUP_DONE) {
742 				bcopy(dr->dr_resp.buf, res, size);
743 				if (dupcachedp != NULL)
744 					*dupcachedp = (dr->dr_resfree != NULL);
745 			} else {
746 				dr->dr_status = DUP_INPROGRESS;
747 				*drpp = dr;
748 			}
749 			RSSTAT_INCR(stats, rsdupreqs);
750 			mutex_exit(&dupreq_lock);
751 			return (status);
752 		}
753 		dr = dr->dr_chain;
754 	}
755 
756 	/*
757 	 * There wasn't an entry, either allocate a new one or recycle
758 	 * an old one.
759 	 */
760 	if (ndupreqs < maxdupreqs) {
761 		dr = kmem_alloc(sizeof (*dr), KM_NOSLEEP);
762 		if (dr == NULL) {
763 			mutex_exit(&dupreq_lock);
764 			return (DUP_ERROR);
765 		}
766 		dr->dr_resp.buf = NULL;
767 		dr->dr_resp.maxlen = 0;
768 		dr->dr_addr.buf = NULL;
769 		dr->dr_addr.maxlen = 0;
770 		if (drmru) {
771 			dr->dr_next = drmru->dr_next;
772 			drmru->dr_next = dr;
773 		} else {
774 			dr->dr_next = dr;
775 		}
776 		ndupreqs++;
777 	} else {
778 		dr = drmru->dr_next;
779 		while (dr->dr_status == DUP_INPROGRESS) {
780 			dr = dr->dr_next;
781 			if (dr == drmru->dr_next) {
782 				cmn_err(CE_WARN, "svc_clts_kdup no slots free");
783 				mutex_exit(&dupreq_lock);
784 				return (DUP_ERROR);
785 			}
786 		}
787 		unhash(dr);
788 		if (dr->dr_resfree) {
789 			(*dr->dr_resfree)(dr->dr_resp.buf);
790 		}
791 	}
792 	dr->dr_resfree = NULL;
793 	drmru = dr;
794 
795 	dr->dr_xid = REQTOXID(req);
796 	dr->dr_prog = req->rq_prog;
797 	dr->dr_vers = req->rq_vers;
798 	dr->dr_proc = req->rq_proc;
799 	if (dr->dr_addr.maxlen < req->rq_xprt->xp_rtaddr.len) {
800 		if (dr->dr_addr.buf != NULL)
801 			kmem_free(dr->dr_addr.buf, dr->dr_addr.maxlen);
802 		dr->dr_addr.maxlen = req->rq_xprt->xp_rtaddr.len;
803 		dr->dr_addr.buf = kmem_alloc(dr->dr_addr.maxlen,
804 		    KM_NOSLEEP);
805 		if (dr->dr_addr.buf == NULL) {
806 			dr->dr_addr.maxlen = 0;
807 			dr->dr_status = DUP_DROP;
808 			mutex_exit(&dupreq_lock);
809 			return (DUP_ERROR);
810 		}
811 	}
812 	dr->dr_addr.len = req->rq_xprt->xp_rtaddr.len;
813 	bcopy(req->rq_xprt->xp_rtaddr.buf, dr->dr_addr.buf, dr->dr_addr.len);
814 	if (dr->dr_resp.maxlen < size) {
815 		if (dr->dr_resp.buf != NULL)
816 			kmem_free(dr->dr_resp.buf, dr->dr_resp.maxlen);
817 		dr->dr_resp.maxlen = (unsigned int)size;
818 		dr->dr_resp.buf = kmem_alloc(size, KM_NOSLEEP);
819 		if (dr->dr_resp.buf == NULL) {
820 			dr->dr_resp.maxlen = 0;
821 			dr->dr_status = DUP_DROP;
822 			mutex_exit(&dupreq_lock);
823 			return (DUP_ERROR);
824 		}
825 	}
826 	dr->dr_status = DUP_INPROGRESS;
827 
828 	drhash = (uint32_t)DRHASH(dr);
829 	dr->dr_chain = drhashtbl[drhash];
830 	drhashtbl[drhash] = dr;
831 	drhashstat[drhash]++;
832 	mutex_exit(&dupreq_lock);
833 	*drpp = dr;
834 	return (DUP_NEW);
835 }
836 
837 /*
838  * PSARC 2003/523 Contract Private Interface
839  * svc_clts_kdupdone
840  * Changes must be reviewed by Solaris File Sharing
841  * Changes must be communicated to contract-2003-523@sun.com
842  *
843  * svc_clts_kdupdone marks the request done (DUP_DONE or DUP_DROP)
844  * and stores the response.
845  */
846 static void
847 svc_clts_kdupdone(struct dupreq *dr, caddr_t res, void (*dis_resfree)(),
848 	int size, int status)
849 {
850 
851 	ASSERT(dr->dr_resfree == NULL);
852 	if (status == DUP_DONE) {
853 		bcopy(res, dr->dr_resp.buf, size);
854 		dr->dr_resfree = dis_resfree;
855 	}
856 	dr->dr_status = status;
857 }
858 
859 /*
860  * This routine expects that the mutex, dupreq_lock, is already held.
861  */
862 static void
863 unhash(struct dupreq *dr)
864 {
865 	struct dupreq *drt;
866 	struct dupreq *drtprev = NULL;
867 	uint32_t drhash;
868 
869 	ASSERT(MUTEX_HELD(&dupreq_lock));
870 
871 	drhash = (uint32_t)DRHASH(dr);
872 	drt = drhashtbl[drhash];
873 	while (drt != NULL) {
874 		if (drt == dr) {
875 			drhashstat[drhash]--;
876 			if (drtprev == NULL) {
877 				drhashtbl[drhash] = drt->dr_chain;
878 			} else {
879 				drtprev->dr_chain = drt->dr_chain;
880 			}
881 			return;
882 		}
883 		drtprev = drt;
884 		drt = drt->dr_chain;
885 	}
886 }
887 
888 void
889 svc_clts_stats_init(zoneid_t zoneid, struct rpc_clts_server **statsp)
890 {
891 	kstat_t *ksp;
892 	kstat_named_t *knp;
893 
894 	knp = rpcstat_zone_init_common(zoneid, "unix", "rpc_clts_server",
895 	    (const kstat_named_t *)&clts_rsstat_tmpl,
896 	    sizeof (clts_rsstat_tmpl));
897 	/*
898 	 * Backwards compatibility for old kstat clients
899 	 */
900 	ksp = kstat_create_zone("unix", 0, "rpc_server", "rpc",
901 	    KSTAT_TYPE_NAMED, clts_rsstat_ndata,
902 	    KSTAT_FLAG_VIRTUAL | KSTAT_FLAG_WRITABLE, zoneid);
903 	if (ksp) {
904 		ksp->ks_data = knp;
905 		kstat_install(ksp);
906 	}
907 	*statsp = (struct rpc_clts_server *)knp;
908 }
909 
910 void
911 svc_clts_stats_fini(zoneid_t zoneid, struct rpc_clts_server **statsp)
912 {
913 	rpcstat_zone_fini_common(zoneid, "unix", "rpc_clts_server");
914 	kstat_delete_byname_zone("unix", 0, "rpc_server", zoneid);
915 	kmem_free(*statsp, sizeof (clts_rsstat_tmpl));
916 }
917 
918 void
919 svc_clts_init()
920 {
921 	/*
922 	 * Check to make sure that the clts private data will fit into
923 	 * the stack buffer allocated by svc_run.  The compiler should
924 	 * remove this check, but it's a safety net if the udp_data
925 	 * structure ever changes.
926 	 */
927 	/*CONSTANTCONDITION*/
928 	ASSERT(sizeof (struct udp_data) <= SVC_P2LEN);
929 
930 	mutex_init(&dupreq_lock, NULL, MUTEX_DEFAULT, NULL);
931 }
932