xref: /illumos-gate/usr/src/uts/common/rpc/svc_cots.c (revision e9af4bc0b1cc30cea75d6ad4aa2fde97d985e9be)
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 2008 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_cots.c
36  * Server side for connection-oriented 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/strsun.h>
47 #include <sys/stropts.h>
48 #include <sys/tiuser.h>
49 #include <sys/timod.h>
50 #include <sys/tihdr.h>
51 #include <sys/fcntl.h>
52 #include <sys/errno.h>
53 #include <sys/kmem.h>
54 #include <sys/systm.h>
55 #include <sys/debug.h>
56 #include <sys/cmn_err.h>
57 #include <sys/kstat.h>
58 #include <sys/vtrace.h>
59 
60 #include <rpc/types.h>
61 #include <rpc/xdr.h>
62 #include <rpc/auth.h>
63 #include <rpc/rpc_msg.h>
64 #include <rpc/svc.h>
65 #include <inet/ip.h>
66 
67 #define	COTS_MAX_ALLOCSIZE	2048
68 #define	MSG_OFFSET		128	/* offset of call into the mblk */
69 #define	RM_HDR_SIZE		4	/* record mark header size */
70 
71 /*
72  * Routines exported through ops vector.
73  */
74 static bool_t		svc_cots_krecv(SVCXPRT *, mblk_t *, struct rpc_msg *);
75 static bool_t		svc_cots_ksend(SVCXPRT *, struct rpc_msg *);
76 static bool_t		svc_cots_kgetargs(SVCXPRT *, xdrproc_t, caddr_t);
77 static bool_t		svc_cots_kfreeargs(SVCXPRT *, xdrproc_t, caddr_t);
78 static void		svc_cots_kdestroy(SVCMASTERXPRT *);
79 static int		svc_cots_kdup(struct svc_req *, caddr_t, int,
80 				struct dupreq **, bool_t *);
81 static void		svc_cots_kdupdone(struct dupreq *, caddr_t,
82 				void (*)(), int, int);
83 static int32_t		*svc_cots_kgetres(SVCXPRT *, int);
84 static void		svc_cots_kfreeres(SVCXPRT *);
85 static void		svc_cots_kclone_destroy(SVCXPRT *);
86 static void		svc_cots_kstart(SVCMASTERXPRT *);
87 
88 /*
89  * Server transport operations vector.
90  */
91 struct svc_ops svc_cots_op = {
92 	svc_cots_krecv,		/* Get requests */
93 	svc_cots_kgetargs,	/* Deserialize arguments */
94 	svc_cots_ksend,		/* Send reply */
95 	svc_cots_kfreeargs,	/* Free argument data space */
96 	svc_cots_kdestroy,	/* Destroy transport handle */
97 	svc_cots_kdup,		/* Check entry in dup req cache */
98 	svc_cots_kdupdone,	/* Mark entry in dup req cache as done */
99 	svc_cots_kgetres,	/* Get pointer to response buffer */
100 	svc_cots_kfreeres,	/* Destroy pre-serialized response header */
101 	svc_cots_kclone_destroy, /* Destroy a clone xprt */
102 	svc_cots_kstart		/* Tell `ready-to-receive' to rpcmod */
103 };
104 
105 /*
106  * Master transport private data.
107  * Kept in xprt->xp_p2.
108  */
109 struct cots_master_data {
110 	char	*cmd_src_addr;	/* client's address */
111 	int	cmd_xprt_started; /* flag for clone routine to call */
112 				/* rpcmod's start routine. */
113 	struct rpc_cots_server *cmd_stats;	/* stats for zone */
114 };
115 
116 /*
117  * Transport private data.
118  * Kept in clone_xprt->xp_p2buf.
119  */
120 typedef struct cots_data {
121 	mblk_t	*cd_mp;		/* pre-allocated reply message */
122 	mblk_t	*cd_req_mp;	/* request message */
123 } cots_data_t;
124 
125 /*
126  * Server statistics
127  * NOTE: This structure type is duplicated in the NFS fast path.
128  */
129 static const struct rpc_cots_server {
130 	kstat_named_t	rscalls;
131 	kstat_named_t	rsbadcalls;
132 	kstat_named_t	rsnullrecv;
133 	kstat_named_t	rsbadlen;
134 	kstat_named_t	rsxdrcall;
135 	kstat_named_t	rsdupchecks;
136 	kstat_named_t	rsdupreqs;
137 } cots_rsstat_tmpl = {
138 	{ "calls",	KSTAT_DATA_UINT64 },
139 	{ "badcalls",	KSTAT_DATA_UINT64 },
140 	{ "nullrecv",	KSTAT_DATA_UINT64 },
141 	{ "badlen",	KSTAT_DATA_UINT64 },
142 	{ "xdrcall",	KSTAT_DATA_UINT64 },
143 	{ "dupchecks",	KSTAT_DATA_UINT64 },
144 	{ "dupreqs",	KSTAT_DATA_UINT64 }
145 };
146 
147 #define	CLONE2STATS(clone_xprt)	\
148 	((struct cots_master_data *)(clone_xprt)->xp_master->xp_p2)->cmd_stats
149 #define	RSSTAT_INCR(s, x)	\
150 	atomic_add_64(&(s)->x.value.ui64, 1)
151 
152 /*
153  * Pointer to a transport specific `ready to receive' function in rpcmod
154  * (set from rpcmod).
155  */
156 void    (*mir_start)(queue_t *);
157 uint_t	*svc_max_msg_sizep;
158 
159 /*
160  * the address size of the underlying transport can sometimes be
161  * unknown (tinfo->ADDR_size == -1).  For this case, it is
162  * necessary to figure out what the size is so the correct amount
163  * of data is allocated.  This is an itterative process:
164  *	1. take a good guess (use T_MINADDRSIZE)
165  *	2. try it.
166  *	3. if it works then everything is ok
167  *	4. if the error is ENAMETOLONG, double the guess
168  *	5. go back to step 2.
169  */
170 #define	T_UNKNOWNADDRSIZE	(-1)
171 #define	T_MINADDRSIZE	32
172 
173 /*
174  * Create a transport record.
175  * The transport record, output buffer, and private data structure
176  * are allocated.  The output buffer is serialized into using xdrmem.
177  * There is one transport record per user process which implements a
178  * set of services.
179  */
180 static kmutex_t cots_kcreate_lock;
181 
182 int
183 svc_cots_kcreate(file_t *fp, uint_t max_msgsize, struct T_info_ack *tinfo,
184     SVCMASTERXPRT **nxprt)
185 {
186 	struct cots_master_data *cmd;
187 	int err, retval;
188 	SVCMASTERXPRT *xprt;
189 	struct rpcstat *rpcstat;
190 	struct T_addr_ack *ack_p;
191 	struct strioctl getaddr;
192 
193 	if (nxprt == NULL)
194 		return (EINVAL);
195 
196 	rpcstat = zone_getspecific(rpcstat_zone_key, curproc->p_zone);
197 	ASSERT(rpcstat != NULL);
198 
199 	xprt = kmem_zalloc(sizeof (SVCMASTERXPRT), KM_SLEEP);
200 
201 	cmd = kmem_zalloc(sizeof (*cmd) + sizeof (*ack_p)
202 	    + (2 * sizeof (sin6_t)), KM_SLEEP);
203 
204 	ack_p = (struct T_addr_ack *)&cmd[1];
205 
206 	if ((tinfo->TIDU_size > COTS_MAX_ALLOCSIZE) ||
207 	    (tinfo->TIDU_size <= 0))
208 		xprt->xp_msg_size = COTS_MAX_ALLOCSIZE;
209 	else {
210 		xprt->xp_msg_size = tinfo->TIDU_size -
211 		    (tinfo->TIDU_size % BYTES_PER_XDR_UNIT);
212 	}
213 
214 	xprt->xp_ops = &svc_cots_op;
215 	xprt->xp_p2 = (caddr_t)cmd;
216 	cmd->cmd_xprt_started = 0;
217 	cmd->cmd_stats = rpcstat->rpc_cots_server;
218 
219 	getaddr.ic_cmd = TI_GETINFO;
220 	getaddr.ic_timout = -1;
221 	getaddr.ic_len = sizeof (*ack_p) + (2 * sizeof (sin6_t));
222 	getaddr.ic_dp = (char *)ack_p;
223 	ack_p->PRIM_type = T_ADDR_REQ;
224 
225 	err = strioctl(fp->f_vnode, I_STR, (intptr_t)&getaddr,
226 	    0, K_TO_K, CRED(), &retval);
227 	if (err) {
228 		kmem_free(cmd, sizeof (*cmd) + sizeof (*ack_p) +
229 		    (2 * sizeof (sin6_t)));
230 		kmem_free(xprt, sizeof (SVCMASTERXPRT));
231 		return (err);
232 	}
233 
234 	xprt->xp_rtaddr.maxlen = ack_p->REMADDR_length;
235 	xprt->xp_rtaddr.len = ack_p->REMADDR_length;
236 	cmd->cmd_src_addr = xprt->xp_rtaddr.buf =
237 	    (char *)ack_p + ack_p->REMADDR_offset;
238 
239 	xprt->xp_lcladdr.maxlen = ack_p->LOCADDR_length;
240 	xprt->xp_lcladdr.len = ack_p->LOCADDR_length;
241 	xprt->xp_lcladdr.buf = (char *)ack_p + ack_p->LOCADDR_offset;
242 
243 	/*
244 	 * If the current sanity check size in rpcmod is smaller
245 	 * than the size needed for this xprt, then increase
246 	 * the sanity check.
247 	 */
248 	if (max_msgsize != 0 && svc_max_msg_sizep &&
249 	    max_msgsize > *svc_max_msg_sizep) {
250 
251 		/* This check needs a lock */
252 		mutex_enter(&cots_kcreate_lock);
253 		if (svc_max_msg_sizep && max_msgsize > *svc_max_msg_sizep)
254 			*svc_max_msg_sizep = max_msgsize;
255 		mutex_exit(&cots_kcreate_lock);
256 	}
257 
258 	*nxprt = xprt;
259 
260 	return (0);
261 }
262 
263 /*
264  * Destroy a master transport record.
265  * Frees the space allocated for a transport record.
266  */
267 static void
268 svc_cots_kdestroy(SVCMASTERXPRT *xprt)
269 {
270 	struct cots_master_data *cmd = (struct cots_master_data *)xprt->xp_p2;
271 
272 	ASSERT(cmd);
273 
274 	if (xprt->xp_netid)
275 		kmem_free(xprt->xp_netid, strlen(xprt->xp_netid) + 1);
276 	if (xprt->xp_addrmask.maxlen)
277 		kmem_free(xprt->xp_addrmask.buf, xprt->xp_addrmask.maxlen);
278 
279 	mutex_destroy(&xprt->xp_req_lock);
280 	mutex_destroy(&xprt->xp_thread_lock);
281 
282 	kmem_free(cmd, sizeof (*cmd) + sizeof (struct T_addr_ack) +
283 	    (2 * sizeof (sin6_t)));
284 
285 	kmem_free(xprt, sizeof (SVCMASTERXPRT));
286 }
287 
288 /*
289  * svc_tli_kcreate() calls this function at the end to tell
290  * rpcmod that the transport is ready to receive requests.
291  */
292 static void
293 svc_cots_kstart(SVCMASTERXPRT *xprt)
294 {
295 	struct cots_master_data *cmd = (struct cots_master_data *)xprt->xp_p2;
296 
297 	if (cmd->cmd_xprt_started == 0) {
298 		/*
299 		 * Acquire the xp_req_lock in order to use xp_wq
300 		 * safely (we don't want to qenable a queue that has
301 		 * already been closed).
302 		 */
303 		mutex_enter(&xprt->xp_req_lock);
304 		if (cmd->cmd_xprt_started == 0 &&
305 		    xprt->xp_wq != NULL) {
306 			(*mir_start)(xprt->xp_wq);
307 			cmd->cmd_xprt_started = 1;
308 		}
309 		mutex_exit(&xprt->xp_req_lock);
310 	}
311 }
312 
313 /*
314  * Transport-type specific part of svc_xprt_cleanup().
315  */
316 static void
317 svc_cots_kclone_destroy(SVCXPRT *clone_xprt)
318 {
319 	cots_data_t *cd = (cots_data_t *)clone_xprt->xp_p2buf;
320 
321 	if (cd->cd_req_mp) {
322 		freemsg(cd->cd_req_mp);
323 		cd->cd_req_mp = (mblk_t *)0;
324 	}
325 	ASSERT(cd->cd_mp == NULL);
326 }
327 
328 /*
329  * Receive rpc requests.
330  * Checks if the message is intact, and deserializes the call packet.
331  */
332 static bool_t
333 svc_cots_krecv(SVCXPRT *clone_xprt, mblk_t *mp, struct rpc_msg *msg)
334 {
335 	cots_data_t *cd = (cots_data_t *)clone_xprt->xp_p2buf;
336 	XDR *xdrs = &clone_xprt->xp_xdrin;
337 	struct rpc_cots_server *stats = CLONE2STATS(clone_xprt);
338 
339 	TRACE_0(TR_FAC_KRPC, TR_SVC_COTS_KRECV_START,
340 	    "svc_cots_krecv_start:");
341 	RPCLOG(4, "svc_cots_krecv_start clone_xprt = %p:\n",
342 	    (void *)clone_xprt);
343 
344 	RSSTAT_INCR(stats, rscalls);
345 
346 	if (mp->b_datap->db_type != M_DATA) {
347 		RPCLOG(16, "svc_cots_krecv bad db_type %d\n",
348 		    mp->b_datap->db_type);
349 		goto bad;
350 	}
351 
352 	xdrmblk_init(xdrs, mp, XDR_DECODE, 0);
353 
354 	TRACE_0(TR_FAC_KRPC, TR_XDR_CALLMSG_START,
355 	    "xdr_callmsg_start:");
356 	RPCLOG0(4, "xdr_callmsg_start:\n");
357 	if (!xdr_callmsg(xdrs, msg)) {
358 		TRACE_1(TR_FAC_KRPC, TR_XDR_CALLMSG_END,
359 		    "xdr_callmsg_end:(%S)", "bad");
360 		RPCLOG0(1, "svc_cots_krecv xdr_callmsg failure\n");
361 		RSSTAT_INCR(stats, rsxdrcall);
362 		goto bad;
363 	}
364 	TRACE_1(TR_FAC_KRPC, TR_XDR_CALLMSG_END,
365 	    "xdr_callmsg_end:(%S)", "good");
366 
367 	clone_xprt->xp_xid = msg->rm_xid;
368 	cd->cd_req_mp = mp;
369 
370 	TRACE_1(TR_FAC_KRPC, TR_SVC_COTS_KRECV_END,
371 	    "svc_cots_krecv_end:(%S)", "good");
372 	RPCLOG0(4, "svc_cots_krecv_end:good\n");
373 	return (TRUE);
374 
375 bad:
376 	if (mp)
377 		freemsg(mp);
378 
379 	RSSTAT_INCR(stats, rsbadcalls);
380 	TRACE_1(TR_FAC_KRPC, TR_SVC_COTS_KRECV_END,
381 	    "svc_cots_krecv_end:(%S)", "bad");
382 	return (FALSE);
383 }
384 
385 /*
386  * Send rpc reply.
387  */
388 static bool_t
389 svc_cots_ksend(SVCXPRT *clone_xprt, struct rpc_msg *msg)
390 {
391 	/* LINTED pointer alignment */
392 	cots_data_t *cd = (cots_data_t *)clone_xprt->xp_p2buf;
393 	XDR *xdrs = &(clone_xprt->xp_xdrout);
394 	int retval = FALSE;
395 	mblk_t *mp;
396 	xdrproc_t xdr_results;
397 	caddr_t xdr_location;
398 	bool_t has_args;
399 
400 	TRACE_0(TR_FAC_KRPC, TR_SVC_COTS_KSEND_START,
401 	    "svc_cots_ksend_start:");
402 
403 	/*
404 	 * If there is a result procedure specified in the reply message,
405 	 * it will be processed in the xdr_replymsg and SVCAUTH_WRAP.
406 	 * We need to make sure it won't be processed twice, so we null
407 	 * it for xdr_replymsg here.
408 	 */
409 	has_args = FALSE;
410 	if (msg->rm_reply.rp_stat == MSG_ACCEPTED &&
411 	    msg->rm_reply.rp_acpt.ar_stat == SUCCESS) {
412 		if ((xdr_results = msg->acpted_rply.ar_results.proc) != NULL) {
413 			has_args = TRUE;
414 			xdr_location = msg->acpted_rply.ar_results.where;
415 			msg->acpted_rply.ar_results.proc = xdr_void;
416 			msg->acpted_rply.ar_results.where = NULL;
417 		}
418 	}
419 
420 	mp = cd->cd_mp;
421 	if (mp) {
422 		/*
423 		 * The program above pre-allocated an mblk and put
424 		 * the data in place.
425 		 */
426 		cd->cd_mp = (mblk_t *)NULL;
427 		if (!(xdr_replymsg_body(xdrs, msg) &&
428 		    (!has_args || SVCAUTH_WRAP(&clone_xprt->xp_auth, xdrs,
429 		    xdr_results, xdr_location)))) {
430 			RPCLOG0(1, "svc_cots_ksend: "
431 			    "xdr_replymsg_body/SVCAUTH_WRAP failed\n");
432 			freemsg(mp);
433 			goto out;
434 		}
435 	} else {
436 		int	len;
437 		int	mpsize;
438 
439 		/*
440 		 * Leave space for protocol headers.
441 		 */
442 		len = MSG_OFFSET + clone_xprt->xp_msg_size;
443 
444 		/*
445 		 * Allocate an initial mblk for the response data.
446 		 */
447 		while (!(mp = allocb(len, BPRI_LO))) {
448 			RPCLOG0(16, "svc_cots_ksend: allocb failed failed\n");
449 			if (strwaitbuf(len, BPRI_LO)) {
450 				TRACE_1(TR_FAC_KRPC, TR_SVC_COTS_KSEND_END,
451 				    "svc_cots_ksend_end:(%S)", "strwaitbuf");
452 				RPCLOG0(1,
453 				    "svc_cots_ksend: strwaitbuf failed\n");
454 				goto out;
455 			}
456 		}
457 
458 		/*
459 		 * Initialize the XDR decode stream.  Additional mblks
460 		 * will be allocated if necessary.  They will be TIDU
461 		 * sized.
462 		 */
463 		xdrmblk_init(xdrs, mp, XDR_ENCODE, clone_xprt->xp_msg_size);
464 		mpsize = MBLKSIZE(mp);
465 		ASSERT(mpsize >= len);
466 		ASSERT(mp->b_rptr == mp->b_datap->db_base);
467 
468 		/*
469 		 * If the size of mblk is not appreciably larger than what we
470 		 * asked, then resize the mblk to exactly len bytes. Reason for
471 		 * this: suppose len is 1600 bytes, the tidu is 1460 bytes
472 		 * (from TCP over ethernet), and the arguments to RPC require
473 		 * 2800 bytes. Ideally we want the protocol to render two
474 		 * ~1400 byte segments over the wire. If allocb() gives us a 2k
475 		 * mblk, and we allocate a second mblk for the rest, the
476 		 * protocol module may generate 3 segments over the wire:
477 		 * 1460 bytes for the first, 448 (2048 - 1600) for the 2nd, and
478 		 * 892 for the 3rd. If we "waste" 448 bytes in the first mblk,
479 		 * the XDR encoding will generate two ~1400 byte mblks, and the
480 		 * protocol module is more likely to produce properly sized
481 		 * segments.
482 		 */
483 		if ((mpsize >> 1) <= len) {
484 			mp->b_rptr += (mpsize - len);
485 		}
486 
487 		/*
488 		 * Adjust b_rptr to reserve space for the non-data protocol
489 		 * headers that any downstream modules might like to add, and
490 		 * for the record marking header.
491 		 */
492 		mp->b_rptr += (MSG_OFFSET + RM_HDR_SIZE);
493 
494 		XDR_SETPOS(xdrs, (uint_t)(mp->b_rptr - mp->b_datap->db_base));
495 		ASSERT(mp->b_wptr == mp->b_rptr);
496 
497 		msg->rm_xid = clone_xprt->xp_xid;
498 
499 		TRACE_0(TR_FAC_KRPC, TR_XDR_REPLYMSG_START,
500 		    "xdr_replymsg_start:");
501 		if (!(xdr_replymsg(xdrs, msg) &&
502 		    (!has_args || SVCAUTH_WRAP(&clone_xprt->xp_auth, xdrs,
503 		    xdr_results, xdr_location)))) {
504 			TRACE_1(TR_FAC_KRPC, TR_XDR_REPLYMSG_END,
505 			    "xdr_replymsg_end:(%S)", "bad");
506 			freemsg(mp);
507 			RPCLOG0(1, "svc_cots_ksend: xdr_replymsg/SVCAUTH_WRAP "
508 			    "failed\n");
509 			goto out;
510 		}
511 		TRACE_1(TR_FAC_KRPC, TR_XDR_REPLYMSG_END,
512 		    "xdr_replymsg_end:(%S)", "good");
513 	}
514 
515 	put(clone_xprt->xp_wq, mp);
516 	retval = TRUE;
517 
518 out:
519 	/*
520 	 * This is completely disgusting.  If public is set it is
521 	 * a pointer to a structure whose first field is the address
522 	 * of the function to free that structure and any related
523 	 * stuff.  (see rrokfree in nfs_xdr.c).
524 	 */
525 	if (xdrs->x_public) {
526 		/* LINTED pointer alignment */
527 		(**((int (**)())xdrs->x_public))(xdrs->x_public);
528 	}
529 
530 	TRACE_1(TR_FAC_KRPC, TR_SVC_COTS_KSEND_END,
531 	    "svc_cots_ksend_end:(%S)", "done");
532 	return (retval);
533 }
534 
535 /*
536  * Deserialize arguments.
537  */
538 static bool_t
539 svc_cots_kgetargs(SVCXPRT *clone_xprt, xdrproc_t xdr_args,
540     caddr_t args_ptr)
541 {
542 	return (SVCAUTH_UNWRAP(&clone_xprt->xp_auth, &clone_xprt->xp_xdrin,
543 	    xdr_args, args_ptr));
544 }
545 
546 static bool_t
547 svc_cots_kfreeargs(SVCXPRT *clone_xprt, xdrproc_t xdr_args,
548     caddr_t args_ptr)
549 {
550 	cots_data_t *cd = (cots_data_t *)clone_xprt->xp_p2buf;
551 	mblk_t *mp;
552 	bool_t retval;
553 
554 	/*
555 	 * It is important to call the XDR routine before
556 	 * freeing the request mblk.  Structures in the
557 	 * XDR data may point into the mblk and require that
558 	 * the memory be intact during the free routine.
559 	 */
560 	if (args_ptr) {
561 		/* LINTED pointer alignment */
562 		XDR	*xdrs = &clone_xprt->xp_xdrin;
563 
564 		xdrs->x_op = XDR_FREE;
565 		retval = (*xdr_args)(xdrs, args_ptr);
566 	} else
567 		retval = TRUE;
568 
569 	if ((mp = cd->cd_req_mp) != NULL) {
570 		cd->cd_req_mp = (mblk_t *)0;
571 		freemsg(mp);
572 	}
573 
574 	return (retval);
575 }
576 
577 static int32_t *
578 svc_cots_kgetres(SVCXPRT *clone_xprt, int size)
579 {
580 	/* LINTED pointer alignment */
581 	cots_data_t *cd = (cots_data_t *)clone_xprt->xp_p2buf;
582 	XDR *xdrs = &clone_xprt->xp_xdrout;
583 	mblk_t *mp;
584 	int32_t *buf;
585 	struct rpc_msg rply;
586 	int len;
587 	int mpsize;
588 
589 	/*
590 	 * Leave space for protocol headers.
591 	 */
592 	len = MSG_OFFSET + clone_xprt->xp_msg_size;
593 
594 	/*
595 	 * Allocate an initial mblk for the response data.
596 	 */
597 	while ((mp = allocb(len, BPRI_LO)) == NULL) {
598 		if (strwaitbuf(len, BPRI_LO))
599 			return (FALSE);
600 	}
601 
602 	/*
603 	 * Initialize the XDR decode stream.  Additional mblks
604 	 * will be allocated if necessary.  They will be TIDU
605 	 * sized.
606 	 */
607 	xdrmblk_init(xdrs, mp, XDR_ENCODE, clone_xprt->xp_msg_size);
608 	mpsize = MBLKSIZE(mp);
609 	ASSERT(mpsize >= len);
610 	ASSERT(mp->b_rptr == mp->b_datap->db_base);
611 
612 	/*
613 	 * If the size of mblk is not appreciably larger than what we
614 	 * asked, then resize the mblk to exactly len bytes. Reason for
615 	 * this: suppose len is 1600 bytes, the tidu is 1460 bytes
616 	 * (from TCP over ethernet), and the arguments to RPC require
617 	 * 2800 bytes. Ideally we want the protocol to render two
618 	 * ~1400 byte segments over the wire. If allocb() gives us a 2k
619 	 * mblk, and we allocate a second mblk for the rest, the
620 	 * protocol module may generate 3 segments over the wire:
621 	 * 1460 bytes for the first, 448 (2048 - 1600) for the 2nd, and
622 	 * 892 for the 3rd. If we "waste" 448 bytes in the first mblk,
623 	 * the XDR encoding will generate two ~1400 byte mblks, and the
624 	 * protocol module is more likely to produce properly sized
625 	 * segments.
626 	 */
627 	if ((mpsize >> 1) <= len) {
628 		mp->b_rptr += (mpsize - len);
629 	}
630 
631 	/*
632 	 * Adjust b_rptr to reserve space for the non-data protocol
633 	 * headers that any downstream modules might like to add, and
634 	 * for the record marking header.
635 	 */
636 	mp->b_rptr += (MSG_OFFSET + RM_HDR_SIZE);
637 
638 	XDR_SETPOS(xdrs, (uint_t)(mp->b_rptr - mp->b_datap->db_base));
639 	ASSERT(mp->b_wptr == mp->b_rptr);
640 
641 	/*
642 	 * Assume a successful RPC since most of them are.
643 	 */
644 	rply.rm_xid = clone_xprt->xp_xid;
645 	rply.rm_direction = REPLY;
646 	rply.rm_reply.rp_stat = MSG_ACCEPTED;
647 	rply.acpted_rply.ar_verf = clone_xprt->xp_verf;
648 	rply.acpted_rply.ar_stat = SUCCESS;
649 
650 	if (!xdr_replymsg_hdr(xdrs, &rply)) {
651 		freeb(mp);
652 		return (NULL);
653 	}
654 
655 
656 	buf = XDR_INLINE(xdrs, size);
657 	if (buf == NULL) {
658 		ASSERT(cd->cd_mp == NULL);
659 		freemsg(mp);
660 	} else {
661 		cd->cd_mp = mp;
662 	}
663 	return (buf);
664 }
665 
666 static void
667 svc_cots_kfreeres(SVCXPRT *clone_xprt)
668 {
669 	cots_data_t *cd;
670 	mblk_t *mp;
671 
672 	cd = (cots_data_t *)clone_xprt->xp_p2buf;
673 	if ((mp = cd->cd_mp) != NULL) {
674 		cd->cd_mp = (mblk_t *)NULL;
675 		freemsg(mp);
676 	}
677 }
678 
679 /*
680  * the dup cacheing routines below provide a cache of non-failure
681  * transaction id's.  rpc service routines can use this to detect
682  * retransmissions and re-send a non-failure response.
683  */
684 
685 /*
686  * MAXDUPREQS is the number of cached items.  It should be adjusted
687  * to the service load so that there is likely to be a response entry
688  * when the first retransmission comes in.
689  */
690 #define	MAXDUPREQS	1024
691 
692 /*
693  * This should be appropriately scaled to MAXDUPREQS.
694  */
695 #define	DRHASHSZ	257
696 
697 #if ((DRHASHSZ & (DRHASHSZ - 1)) == 0)
698 #define	XIDHASH(xid)	((xid) & (DRHASHSZ - 1))
699 #else
700 #define	XIDHASH(xid)	((xid) % DRHASHSZ)
701 #endif
702 #define	DRHASH(dr)	XIDHASH((dr)->dr_xid)
703 #define	REQTOXID(req)	((req)->rq_xprt->xp_xid)
704 
705 static int	cotsndupreqs = 0;
706 int	cotsmaxdupreqs = MAXDUPREQS;
707 static kmutex_t cotsdupreq_lock;
708 static struct dupreq *cotsdrhashtbl[DRHASHSZ];
709 static int	cotsdrhashstat[DRHASHSZ];
710 
711 static void unhash(struct dupreq *);
712 
713 /*
714  * cotsdrmru points to the head of a circular linked list in lru order.
715  * cotsdrmru->dr_next == drlru
716  */
717 struct dupreq *cotsdrmru;
718 
719 /*
720  * PSARC 2003/523 Contract Private Interface
721  * svc_cots_kdup
722  * Changes must be reviewed by Solaris File Sharing
723  * Changes must be communicated to contract-2003-523@sun.com
724  *
725  * svc_cots_kdup searches the request cache and returns 0 if the
726  * request is not found in the cache.  If it is found, then it
727  * returns the state of the request (in progress or done) and
728  * the status or attributes that were part of the original reply.
729  *
730  * If DUP_DONE (there is a duplicate) svc_cots_kdup copies over the
731  * value of the response. In that case, also return in *dupcachedp
732  * whether the response free routine is cached in the dupreq - in which case
733  * the caller should not be freeing it, because it will be done later
734  * in the svc_cots_kdup code when the dupreq is reused.
735  */
736 static int
737 svc_cots_kdup(struct svc_req *req, caddr_t res, int size, struct dupreq **drpp,
738 	bool_t *dupcachedp)
739 {
740 	struct rpc_cots_server *stats = CLONE2STATS(req->rq_xprt);
741 	struct dupreq *dr;
742 	uint32_t xid;
743 	uint32_t drhash;
744 	int status;
745 
746 	xid = REQTOXID(req);
747 	mutex_enter(&cotsdupreq_lock);
748 	RSSTAT_INCR(stats, rsdupchecks);
749 	/*
750 	 * Check to see whether an entry already exists in the cache.
751 	 */
752 	dr = cotsdrhashtbl[XIDHASH(xid)];
753 	while (dr != NULL) {
754 		if (dr->dr_xid == xid &&
755 		    dr->dr_proc == req->rq_proc &&
756 		    dr->dr_prog == req->rq_prog &&
757 		    dr->dr_vers == req->rq_vers &&
758 		    dr->dr_addr.len == req->rq_xprt->xp_rtaddr.len &&
759 		    bcmp((caddr_t)dr->dr_addr.buf,
760 		    (caddr_t)req->rq_xprt->xp_rtaddr.buf,
761 		    dr->dr_addr.len) == 0) {
762 			status = dr->dr_status;
763 			if (status == DUP_DONE) {
764 				bcopy(dr->dr_resp.buf, res, size);
765 				if (dupcachedp != NULL)
766 					*dupcachedp = (dr->dr_resfree != NULL);
767 				TRACE_0(TR_FAC_KRPC, TR_SVC_COTS_KDUP_DONE,
768 				    "svc_cots_kdup: DUP_DONE");
769 			} else {
770 				dr->dr_status = DUP_INPROGRESS;
771 				*drpp = dr;
772 				TRACE_0(TR_FAC_KRPC,
773 				    TR_SVC_COTS_KDUP_INPROGRESS,
774 				    "svc_cots_kdup: DUP_INPROGRESS");
775 			}
776 			RSSTAT_INCR(stats, rsdupreqs);
777 			mutex_exit(&cotsdupreq_lock);
778 			return (status);
779 		}
780 		dr = dr->dr_chain;
781 	}
782 
783 	/*
784 	 * There wasn't an entry, either allocate a new one or recycle
785 	 * an old one.
786 	 */
787 	if (cotsndupreqs < cotsmaxdupreqs) {
788 		dr = kmem_alloc(sizeof (*dr), KM_NOSLEEP);
789 		if (dr == NULL) {
790 			mutex_exit(&cotsdupreq_lock);
791 			return (DUP_ERROR);
792 		}
793 		dr->dr_resp.buf = NULL;
794 		dr->dr_resp.maxlen = 0;
795 		dr->dr_addr.buf = NULL;
796 		dr->dr_addr.maxlen = 0;
797 		if (cotsdrmru) {
798 			dr->dr_next = cotsdrmru->dr_next;
799 			cotsdrmru->dr_next = dr;
800 		} else {
801 			dr->dr_next = dr;
802 		}
803 		cotsndupreqs++;
804 	} else {
805 		dr = cotsdrmru->dr_next;
806 		while (dr->dr_status == DUP_INPROGRESS) {
807 			dr = dr->dr_next;
808 			if (dr == cotsdrmru->dr_next) {
809 				cmn_err(CE_WARN, "svc_cots_kdup no slots free");
810 				mutex_exit(&cotsdupreq_lock);
811 				return (DUP_ERROR);
812 			}
813 		}
814 		unhash(dr);
815 		if (dr->dr_resfree) {
816 			(*dr->dr_resfree)(dr->dr_resp.buf);
817 		}
818 	}
819 	dr->dr_resfree = NULL;
820 	cotsdrmru = dr;
821 
822 	dr->dr_xid = REQTOXID(req);
823 	dr->dr_prog = req->rq_prog;
824 	dr->dr_vers = req->rq_vers;
825 	dr->dr_proc = req->rq_proc;
826 	if (dr->dr_addr.maxlen < req->rq_xprt->xp_rtaddr.len) {
827 		if (dr->dr_addr.buf != NULL)
828 			kmem_free(dr->dr_addr.buf, dr->dr_addr.maxlen);
829 		dr->dr_addr.maxlen = req->rq_xprt->xp_rtaddr.len;
830 		dr->dr_addr.buf = kmem_alloc(dr->dr_addr.maxlen, KM_NOSLEEP);
831 		if (dr->dr_addr.buf == NULL) {
832 			dr->dr_addr.maxlen = 0;
833 			dr->dr_status = DUP_DROP;
834 			mutex_exit(&cotsdupreq_lock);
835 			return (DUP_ERROR);
836 		}
837 	}
838 	dr->dr_addr.len = req->rq_xprt->xp_rtaddr.len;
839 	bcopy(req->rq_xprt->xp_rtaddr.buf, dr->dr_addr.buf, dr->dr_addr.len);
840 	if (dr->dr_resp.maxlen < size) {
841 		if (dr->dr_resp.buf != NULL)
842 			kmem_free(dr->dr_resp.buf, dr->dr_resp.maxlen);
843 		dr->dr_resp.maxlen = (unsigned int)size;
844 		dr->dr_resp.buf = kmem_alloc(size, KM_NOSLEEP);
845 		if (dr->dr_resp.buf == NULL) {
846 			dr->dr_resp.maxlen = 0;
847 			dr->dr_status = DUP_DROP;
848 			mutex_exit(&cotsdupreq_lock);
849 			return (DUP_ERROR);
850 		}
851 	}
852 	dr->dr_status = DUP_INPROGRESS;
853 
854 	drhash = (uint32_t)DRHASH(dr);
855 	dr->dr_chain = cotsdrhashtbl[drhash];
856 	cotsdrhashtbl[drhash] = dr;
857 	cotsdrhashstat[drhash]++;
858 	mutex_exit(&cotsdupreq_lock);
859 	*drpp = dr;
860 	return (DUP_NEW);
861 }
862 
863 /*
864  * PSARC 2003/523 Contract Private Interface
865  * svc_cots_kdupdone
866  * Changes must be reviewed by Solaris File Sharing
867  * Changes must be communicated to contract-2003-523@sun.com
868  *
869  * svc_cots_kdupdone marks the request done (DUP_DONE or DUP_DROP)
870  * and stores the response.
871  */
872 static void
873 svc_cots_kdupdone(struct dupreq *dr, caddr_t res, void (*dis_resfree)(),
874 	int size, int status)
875 {
876 	ASSERT(dr->dr_resfree == NULL);
877 	if (status == DUP_DONE) {
878 		bcopy(res, dr->dr_resp.buf, size);
879 		dr->dr_resfree = dis_resfree;
880 	}
881 	dr->dr_status = status;
882 }
883 
884 /*
885  * This routine expects that the mutex, cotsdupreq_lock, is already held.
886  */
887 static void
888 unhash(struct dupreq *dr)
889 {
890 	struct dupreq *drt;
891 	struct dupreq *drtprev = NULL;
892 	uint32_t drhash;
893 
894 	ASSERT(MUTEX_HELD(&cotsdupreq_lock));
895 
896 	drhash = (uint32_t)DRHASH(dr);
897 	drt = cotsdrhashtbl[drhash];
898 	while (drt != NULL) {
899 		if (drt == dr) {
900 			cotsdrhashstat[drhash]--;
901 			if (drtprev == NULL) {
902 				cotsdrhashtbl[drhash] = drt->dr_chain;
903 			} else {
904 				drtprev->dr_chain = drt->dr_chain;
905 			}
906 			return;
907 		}
908 		drtprev = drt;
909 		drt = drt->dr_chain;
910 	}
911 }
912 
913 void
914 svc_cots_stats_init(zoneid_t zoneid, struct rpc_cots_server **statsp)
915 {
916 	*statsp = (struct rpc_cots_server *)rpcstat_zone_init_common(zoneid,
917 	    "unix", "rpc_cots_server", (const kstat_named_t *)&cots_rsstat_tmpl,
918 	    sizeof (cots_rsstat_tmpl));
919 }
920 
921 void
922 svc_cots_stats_fini(zoneid_t zoneid, struct rpc_cots_server **statsp)
923 {
924 	rpcstat_zone_fini_common(zoneid, "unix", "rpc_cots_server");
925 	kmem_free(*statsp, sizeof (cots_rsstat_tmpl));
926 }
927 
928 void
929 svc_cots_init(void)
930 {
931 	/*
932 	 * Check to make sure that the cots private data will fit into
933 	 * the stack buffer allocated by svc_run.  The ASSERT is a safety
934 	 * net if the cots_data_t structure ever changes.
935 	 */
936 	/*CONSTANTCONDITION*/
937 	ASSERT(sizeof (cots_data_t) <= SVC_P2LEN);
938 
939 	mutex_init(&cots_kcreate_lock, NULL, MUTEX_DEFAULT, NULL);
940 	mutex_init(&cotsdupreq_lock, NULL, MUTEX_DEFAULT, NULL);
941 }
942