xref: /freebsd/sys/rpc/svc_vc.c (revision 3a92d97ff0f22d21608e1c19b83104c4937523b6)
1 /*	$NetBSD: svc_vc.c,v 1.7 2000/08/03 00:01:53 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 #if defined(LIBC_SCCS) && !defined(lint)
32 static char *sccsid2 = "@(#)svc_tcp.c 1.21 87/08/11 Copyr 1984 Sun Micro";
33 static char *sccsid = "@(#)svc_tcp.c	2.2 88/08/01 4.0 RPCSRC";
34 #endif
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 /*
39  * svc_vc.c, Server side for Connection Oriented based RPC.
40  *
41  * Actually implements two flavors of transporter -
42  * a tcp rendezvouser (a listner and connection establisher)
43  * and a record/tcp stream.
44  */
45 
46 #include <sys/param.h>
47 #include <sys/lock.h>
48 #include <sys/kernel.h>
49 #include <sys/malloc.h>
50 #include <sys/mbuf.h>
51 #include <sys/mutex.h>
52 #include <sys/proc.h>
53 #include <sys/protosw.h>
54 #include <sys/queue.h>
55 #include <sys/socket.h>
56 #include <sys/socketvar.h>
57 #include <sys/sx.h>
58 #include <sys/systm.h>
59 #include <sys/uio.h>
60 
61 #include <net/vnet.h>
62 
63 #include <netinet/tcp.h>
64 
65 #include <rpc/rpc.h>
66 
67 #include <rpc/krpc.h>
68 #include <rpc/rpc_com.h>
69 
70 #include <security/mac/mac_framework.h>
71 
72 static bool_t svc_vc_rendezvous_recv(SVCXPRT *, struct rpc_msg *,
73     struct sockaddr **, struct mbuf **);
74 static enum xprt_stat svc_vc_rendezvous_stat(SVCXPRT *);
75 static void svc_vc_rendezvous_destroy(SVCXPRT *);
76 static bool_t svc_vc_null(void);
77 static void svc_vc_destroy(SVCXPRT *);
78 static enum xprt_stat svc_vc_stat(SVCXPRT *);
79 static bool_t svc_vc_ack(SVCXPRT *, uint32_t *);
80 static bool_t svc_vc_recv(SVCXPRT *, struct rpc_msg *,
81     struct sockaddr **, struct mbuf **);
82 static bool_t svc_vc_reply(SVCXPRT *, struct rpc_msg *,
83     struct sockaddr *, struct mbuf *, uint32_t *seq);
84 static bool_t svc_vc_control(SVCXPRT *xprt, const u_int rq, void *in);
85 static bool_t svc_vc_rendezvous_control (SVCXPRT *xprt, const u_int rq,
86     void *in);
87 static void svc_vc_backchannel_destroy(SVCXPRT *);
88 static enum xprt_stat svc_vc_backchannel_stat(SVCXPRT *);
89 static bool_t svc_vc_backchannel_recv(SVCXPRT *, struct rpc_msg *,
90     struct sockaddr **, struct mbuf **);
91 static bool_t svc_vc_backchannel_reply(SVCXPRT *, struct rpc_msg *,
92     struct sockaddr *, struct mbuf *, uint32_t *);
93 static bool_t svc_vc_backchannel_control(SVCXPRT *xprt, const u_int rq,
94     void *in);
95 static SVCXPRT *svc_vc_create_conn(SVCPOOL *pool, struct socket *so,
96     struct sockaddr *raddr);
97 static int svc_vc_accept(struct socket *head, struct socket **sop);
98 static int svc_vc_soupcall(struct socket *so, void *arg, int waitflag);
99 
100 static struct xp_ops svc_vc_rendezvous_ops = {
101 	.xp_recv =	svc_vc_rendezvous_recv,
102 	.xp_stat =	svc_vc_rendezvous_stat,
103 	.xp_reply =	(bool_t (*)(SVCXPRT *, struct rpc_msg *,
104 		struct sockaddr *, struct mbuf *, uint32_t *))svc_vc_null,
105 	.xp_destroy =	svc_vc_rendezvous_destroy,
106 	.xp_control =	svc_vc_rendezvous_control
107 };
108 
109 static struct xp_ops svc_vc_ops = {
110 	.xp_recv =	svc_vc_recv,
111 	.xp_stat =	svc_vc_stat,
112 	.xp_ack =	svc_vc_ack,
113 	.xp_reply =	svc_vc_reply,
114 	.xp_destroy =	svc_vc_destroy,
115 	.xp_control =	svc_vc_control
116 };
117 
118 static struct xp_ops svc_vc_backchannel_ops = {
119 	.xp_recv =	svc_vc_backchannel_recv,
120 	.xp_stat =	svc_vc_backchannel_stat,
121 	.xp_reply =	svc_vc_backchannel_reply,
122 	.xp_destroy =	svc_vc_backchannel_destroy,
123 	.xp_control =	svc_vc_backchannel_control
124 };
125 
126 /*
127  * Usage:
128  *	xprt = svc_vc_create(sock, send_buf_size, recv_buf_size);
129  *
130  * Creates, registers, and returns a (rpc) tcp based transporter.
131  * Once *xprt is initialized, it is registered as a transporter
132  * see (svc.h, xprt_register).  This routine returns
133  * a NULL if a problem occurred.
134  *
135  * The filedescriptor passed in is expected to refer to a bound, but
136  * not yet connected socket.
137  *
138  * Since streams do buffered io similar to stdio, the caller can specify
139  * how big the send and receive buffers are via the second and third parms;
140  * 0 => use the system default.
141  */
142 SVCXPRT *
143 svc_vc_create(SVCPOOL *pool, struct socket *so, size_t sendsize,
144     size_t recvsize)
145 {
146 	SVCXPRT *xprt;
147 	struct sockaddr* sa;
148 	int error;
149 
150 	SOCK_LOCK(so);
151 	if (so->so_state & (SS_ISCONNECTED|SS_ISDISCONNECTED)) {
152 		SOCK_UNLOCK(so);
153 		error = so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa);
154 		if (error)
155 			return (NULL);
156 		xprt = svc_vc_create_conn(pool, so, sa);
157 		free(sa, M_SONAME);
158 		return (xprt);
159 	}
160 	SOCK_UNLOCK(so);
161 
162 	xprt = svc_xprt_alloc();
163 	sx_init(&xprt->xp_lock, "xprt->xp_lock");
164 	xprt->xp_pool = pool;
165 	xprt->xp_socket = so;
166 	xprt->xp_p1 = NULL;
167 	xprt->xp_p2 = NULL;
168 	xprt->xp_ops = &svc_vc_rendezvous_ops;
169 
170 	error = so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa);
171 	if (error) {
172 		goto cleanup_svc_vc_create;
173 	}
174 
175 	memcpy(&xprt->xp_ltaddr, sa, sa->sa_len);
176 	free(sa, M_SONAME);
177 
178 	xprt_register(xprt);
179 
180 	solisten(so, SOMAXCONN, curthread);
181 
182 	SOCKBUF_LOCK(&so->so_rcv);
183 	xprt->xp_upcallset = 1;
184 	soupcall_set(so, SO_RCV, svc_vc_soupcall, xprt);
185 	SOCKBUF_UNLOCK(&so->so_rcv);
186 
187 	return (xprt);
188 cleanup_svc_vc_create:
189 	if (xprt) {
190 		sx_destroy(&xprt->xp_lock);
191 		svc_xprt_free(xprt);
192 	}
193 	return (NULL);
194 }
195 
196 /*
197  * Create a new transport for a socket optained via soaccept().
198  */
199 SVCXPRT *
200 svc_vc_create_conn(SVCPOOL *pool, struct socket *so, struct sockaddr *raddr)
201 {
202 	SVCXPRT *xprt = NULL;
203 	struct cf_conn *cd = NULL;
204 	struct sockaddr* sa = NULL;
205 	struct sockopt opt;
206 	int one = 1;
207 	int error;
208 
209 	bzero(&opt, sizeof(struct sockopt));
210 	opt.sopt_dir = SOPT_SET;
211 	opt.sopt_level = SOL_SOCKET;
212 	opt.sopt_name = SO_KEEPALIVE;
213 	opt.sopt_val = &one;
214 	opt.sopt_valsize = sizeof(one);
215 	error = sosetopt(so, &opt);
216 	if (error) {
217 		return (NULL);
218 	}
219 
220 	if (so->so_proto->pr_protocol == IPPROTO_TCP) {
221 		bzero(&opt, sizeof(struct sockopt));
222 		opt.sopt_dir = SOPT_SET;
223 		opt.sopt_level = IPPROTO_TCP;
224 		opt.sopt_name = TCP_NODELAY;
225 		opt.sopt_val = &one;
226 		opt.sopt_valsize = sizeof(one);
227 		error = sosetopt(so, &opt);
228 		if (error) {
229 			return (NULL);
230 		}
231 	}
232 
233 	cd = mem_alloc(sizeof(*cd));
234 	cd->strm_stat = XPRT_IDLE;
235 
236 	xprt = svc_xprt_alloc();
237 	sx_init(&xprt->xp_lock, "xprt->xp_lock");
238 	xprt->xp_pool = pool;
239 	xprt->xp_socket = so;
240 	xprt->xp_p1 = cd;
241 	xprt->xp_p2 = NULL;
242 	xprt->xp_ops = &svc_vc_ops;
243 
244 	/*
245 	 * See http://www.connectathon.org/talks96/nfstcp.pdf - client
246 	 * has a 5 minute timer, server has a 6 minute timer.
247 	 */
248 	xprt->xp_idletimeout = 6 * 60;
249 
250 	memcpy(&xprt->xp_rtaddr, raddr, raddr->sa_len);
251 
252 	error = so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa);
253 	if (error)
254 		goto cleanup_svc_vc_create;
255 
256 	memcpy(&xprt->xp_ltaddr, sa, sa->sa_len);
257 	free(sa, M_SONAME);
258 
259 	xprt_register(xprt);
260 
261 	SOCKBUF_LOCK(&so->so_rcv);
262 	xprt->xp_upcallset = 1;
263 	soupcall_set(so, SO_RCV, svc_vc_soupcall, xprt);
264 	SOCKBUF_UNLOCK(&so->so_rcv);
265 
266 	/*
267 	 * Throw the transport into the active list in case it already
268 	 * has some data buffered.
269 	 */
270 	sx_xlock(&xprt->xp_lock);
271 	xprt_active(xprt);
272 	sx_xunlock(&xprt->xp_lock);
273 
274 	return (xprt);
275 cleanup_svc_vc_create:
276 	if (xprt) {
277 		sx_destroy(&xprt->xp_lock);
278 		svc_xprt_free(xprt);
279 	}
280 	if (cd)
281 		mem_free(cd, sizeof(*cd));
282 	return (NULL);
283 }
284 
285 /*
286  * Create a new transport for a backchannel on a clnt_vc socket.
287  */
288 SVCXPRT *
289 svc_vc_create_backchannel(SVCPOOL *pool)
290 {
291 	SVCXPRT *xprt = NULL;
292 	struct cf_conn *cd = NULL;
293 
294 	cd = mem_alloc(sizeof(*cd));
295 	cd->strm_stat = XPRT_IDLE;
296 
297 	xprt = svc_xprt_alloc();
298 	sx_init(&xprt->xp_lock, "xprt->xp_lock");
299 	xprt->xp_pool = pool;
300 	xprt->xp_socket = NULL;
301 	xprt->xp_p1 = cd;
302 	xprt->xp_p2 = NULL;
303 	xprt->xp_ops = &svc_vc_backchannel_ops;
304 	return (xprt);
305 }
306 
307 /*
308  * This does all of the accept except the final call to soaccept. The
309  * caller will call soaccept after dropping its locks (soaccept may
310  * call malloc).
311  */
312 int
313 svc_vc_accept(struct socket *head, struct socket **sop)
314 {
315 	int error = 0;
316 	struct socket *so;
317 
318 	if ((head->so_options & SO_ACCEPTCONN) == 0) {
319 		error = EINVAL;
320 		goto done;
321 	}
322 #ifdef MAC
323 	error = mac_socket_check_accept(curthread->td_ucred, head);
324 	if (error != 0)
325 		goto done;
326 #endif
327 	ACCEPT_LOCK();
328 	if (TAILQ_EMPTY(&head->so_comp)) {
329 		ACCEPT_UNLOCK();
330 		error = EWOULDBLOCK;
331 		goto done;
332 	}
333 	so = TAILQ_FIRST(&head->so_comp);
334 	KASSERT(!(so->so_qstate & SQ_INCOMP), ("svc_vc_accept: so SQ_INCOMP"));
335 	KASSERT(so->so_qstate & SQ_COMP, ("svc_vc_accept: so not SQ_COMP"));
336 
337 	/*
338 	 * Before changing the flags on the socket, we have to bump the
339 	 * reference count.  Otherwise, if the protocol calls sofree(),
340 	 * the socket will be released due to a zero refcount.
341 	 * XXX might not need soref() since this is simpler than kern_accept.
342 	 */
343 	SOCK_LOCK(so);			/* soref() and so_state update */
344 	soref(so);			/* file descriptor reference */
345 
346 	TAILQ_REMOVE(&head->so_comp, so, so_list);
347 	head->so_qlen--;
348 	so->so_state |= (head->so_state & SS_NBIO);
349 	so->so_qstate &= ~SQ_COMP;
350 	so->so_head = NULL;
351 
352 	SOCK_UNLOCK(so);
353 	ACCEPT_UNLOCK();
354 
355 	*sop = so;
356 
357 	/* connection has been removed from the listen queue */
358 	KNOTE_UNLOCKED(&head->so_rcv.sb_sel.si_note, 0);
359 done:
360 	return (error);
361 }
362 
363 /*ARGSUSED*/
364 static bool_t
365 svc_vc_rendezvous_recv(SVCXPRT *xprt, struct rpc_msg *msg,
366     struct sockaddr **addrp, struct mbuf **mp)
367 {
368 	struct socket *so = NULL;
369 	struct sockaddr *sa = NULL;
370 	int error;
371 	SVCXPRT *new_xprt;
372 
373 	/*
374 	 * The socket upcall calls xprt_active() which will eventually
375 	 * cause the server to call us here. We attempt to accept a
376 	 * connection from the socket and turn it into a new
377 	 * transport. If the accept fails, we have drained all pending
378 	 * connections so we call xprt_inactive().
379 	 */
380 	sx_xlock(&xprt->xp_lock);
381 
382 	error = svc_vc_accept(xprt->xp_socket, &so);
383 
384 	if (error == EWOULDBLOCK) {
385 		/*
386 		 * We must re-test for new connections after taking
387 		 * the lock to protect us in the case where a new
388 		 * connection arrives after our call to accept fails
389 		 * with EWOULDBLOCK.
390 		 */
391 		ACCEPT_LOCK();
392 		if (TAILQ_EMPTY(&xprt->xp_socket->so_comp))
393 			xprt_inactive_self(xprt);
394 		ACCEPT_UNLOCK();
395 		sx_xunlock(&xprt->xp_lock);
396 		return (FALSE);
397 	}
398 
399 	if (error) {
400 		SOCKBUF_LOCK(&xprt->xp_socket->so_rcv);
401 		if (xprt->xp_upcallset) {
402 			xprt->xp_upcallset = 0;
403 			soupcall_clear(xprt->xp_socket, SO_RCV);
404 		}
405 		SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv);
406 		xprt_inactive_self(xprt);
407 		sx_xunlock(&xprt->xp_lock);
408 		return (FALSE);
409 	}
410 
411 	sx_xunlock(&xprt->xp_lock);
412 
413 	sa = 0;
414 	error = soaccept(so, &sa);
415 
416 	if (error) {
417 		/*
418 		 * XXX not sure if I need to call sofree or soclose here.
419 		 */
420 		if (sa)
421 			free(sa, M_SONAME);
422 		return (FALSE);
423 	}
424 
425 	/*
426 	 * svc_vc_create_conn will call xprt_register - we don't need
427 	 * to do anything with the new connection except derefence it.
428 	 */
429 	new_xprt = svc_vc_create_conn(xprt->xp_pool, so, sa);
430 	if (!new_xprt) {
431 		soclose(so);
432 	} else {
433 		SVC_RELEASE(new_xprt);
434 	}
435 
436 	free(sa, M_SONAME);
437 
438 	return (FALSE); /* there is never an rpc msg to be processed */
439 }
440 
441 /*ARGSUSED*/
442 static enum xprt_stat
443 svc_vc_rendezvous_stat(SVCXPRT *xprt)
444 {
445 
446 	return (XPRT_IDLE);
447 }
448 
449 static void
450 svc_vc_destroy_common(SVCXPRT *xprt)
451 {
452 	SOCKBUF_LOCK(&xprt->xp_socket->so_rcv);
453 	if (xprt->xp_upcallset) {
454 		xprt->xp_upcallset = 0;
455 		soupcall_clear(xprt->xp_socket, SO_RCV);
456 	}
457 	SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv);
458 
459 	if (xprt->xp_socket)
460 		(void)soclose(xprt->xp_socket);
461 
462 	if (xprt->xp_netid)
463 		(void) mem_free(xprt->xp_netid, strlen(xprt->xp_netid) + 1);
464 	svc_xprt_free(xprt);
465 }
466 
467 static void
468 svc_vc_rendezvous_destroy(SVCXPRT *xprt)
469 {
470 
471 	svc_vc_destroy_common(xprt);
472 }
473 
474 static void
475 svc_vc_destroy(SVCXPRT *xprt)
476 {
477 	struct cf_conn *cd = (struct cf_conn *)xprt->xp_p1;
478 
479 	svc_vc_destroy_common(xprt);
480 
481 	if (cd->mreq)
482 		m_freem(cd->mreq);
483 	if (cd->mpending)
484 		m_freem(cd->mpending);
485 	mem_free(cd, sizeof(*cd));
486 }
487 
488 static void
489 svc_vc_backchannel_destroy(SVCXPRT *xprt)
490 {
491 	struct cf_conn *cd = (struct cf_conn *)xprt->xp_p1;
492 	struct mbuf *m, *m2;
493 
494 	svc_xprt_free(xprt);
495 	m = cd->mreq;
496 	while (m != NULL) {
497 		m2 = m;
498 		m = m->m_nextpkt;
499 		m_freem(m2);
500 	}
501 	mem_free(cd, sizeof(*cd));
502 }
503 
504 /*ARGSUSED*/
505 static bool_t
506 svc_vc_control(SVCXPRT *xprt, const u_int rq, void *in)
507 {
508 	return (FALSE);
509 }
510 
511 static bool_t
512 svc_vc_rendezvous_control(SVCXPRT *xprt, const u_int rq, void *in)
513 {
514 
515 	return (FALSE);
516 }
517 
518 static bool_t
519 svc_vc_backchannel_control(SVCXPRT *xprt, const u_int rq, void *in)
520 {
521 
522 	return (FALSE);
523 }
524 
525 static enum xprt_stat
526 svc_vc_stat(SVCXPRT *xprt)
527 {
528 	struct cf_conn *cd;
529 
530 	cd = (struct cf_conn *)(xprt->xp_p1);
531 
532 	if (cd->strm_stat == XPRT_DIED)
533 		return (XPRT_DIED);
534 
535 	if (cd->mreq != NULL && cd->resid == 0 && cd->eor)
536 		return (XPRT_MOREREQS);
537 
538 	if (soreadable(xprt->xp_socket))
539 		return (XPRT_MOREREQS);
540 
541 	return (XPRT_IDLE);
542 }
543 
544 static bool_t
545 svc_vc_ack(SVCXPRT *xprt, uint32_t *ack)
546 {
547 
548 	*ack = atomic_load_acq_32(&xprt->xp_snt_cnt);
549 	*ack -= xprt->xp_socket->so_snd.sb_cc;
550 	return (TRUE);
551 }
552 
553 static enum xprt_stat
554 svc_vc_backchannel_stat(SVCXPRT *xprt)
555 {
556 	struct cf_conn *cd;
557 
558 	cd = (struct cf_conn *)(xprt->xp_p1);
559 
560 	if (cd->mreq != NULL)
561 		return (XPRT_MOREREQS);
562 
563 	return (XPRT_IDLE);
564 }
565 
566 /*
567  * If we have an mbuf chain in cd->mpending, try to parse a record from it,
568  * leaving the result in cd->mreq. If we don't have a complete record, leave
569  * the partial result in cd->mreq and try to read more from the socket.
570  */
571 static int
572 svc_vc_process_pending(SVCXPRT *xprt)
573 {
574 	struct cf_conn *cd = (struct cf_conn *) xprt->xp_p1;
575 	struct socket *so = xprt->xp_socket;
576 	struct mbuf *m;
577 
578 	/*
579 	 * If cd->resid is non-zero, we have part of the
580 	 * record already, otherwise we are expecting a record
581 	 * marker.
582 	 */
583 	if (!cd->resid && cd->mpending) {
584 		/*
585 		 * See if there is enough data buffered to
586 		 * make up a record marker. Make sure we can
587 		 * handle the case where the record marker is
588 		 * split across more than one mbuf.
589 		 */
590 		size_t n = 0;
591 		uint32_t header;
592 
593 		m = cd->mpending;
594 		while (n < sizeof(uint32_t) && m) {
595 			n += m->m_len;
596 			m = m->m_next;
597 		}
598 		if (n < sizeof(uint32_t)) {
599 			so->so_rcv.sb_lowat = sizeof(uint32_t) - n;
600 			return (FALSE);
601 		}
602 		m_copydata(cd->mpending, 0, sizeof(header),
603 		    (char *)&header);
604 		header = ntohl(header);
605 		cd->eor = (header & 0x80000000) != 0;
606 		cd->resid = header & 0x7fffffff;
607 		m_adj(cd->mpending, sizeof(uint32_t));
608 	}
609 
610 	/*
611 	 * Start pulling off mbufs from cd->mpending
612 	 * until we either have a complete record or
613 	 * we run out of data. We use m_split to pull
614 	 * data - it will pull as much as possible and
615 	 * split the last mbuf if necessary.
616 	 */
617 	while (cd->mpending && cd->resid) {
618 		m = cd->mpending;
619 		if (cd->mpending->m_next
620 		    || cd->mpending->m_len > cd->resid)
621 			cd->mpending = m_split(cd->mpending,
622 			    cd->resid, M_WAITOK);
623 		else
624 			cd->mpending = NULL;
625 		if (cd->mreq)
626 			m_last(cd->mreq)->m_next = m;
627 		else
628 			cd->mreq = m;
629 		while (m) {
630 			cd->resid -= m->m_len;
631 			m = m->m_next;
632 		}
633 	}
634 
635 	/*
636 	 * Block receive upcalls if we have more data pending,
637 	 * otherwise report our need.
638 	 */
639 	if (cd->mpending)
640 		so->so_rcv.sb_lowat = INT_MAX;
641 	else
642 		so->so_rcv.sb_lowat =
643 		    imax(1, imin(cd->resid, so->so_rcv.sb_hiwat / 2));
644 	return (TRUE);
645 }
646 
647 static bool_t
648 svc_vc_recv(SVCXPRT *xprt, struct rpc_msg *msg,
649     struct sockaddr **addrp, struct mbuf **mp)
650 {
651 	struct cf_conn *cd = (struct cf_conn *) xprt->xp_p1;
652 	struct uio uio;
653 	struct mbuf *m;
654 	struct socket* so = xprt->xp_socket;
655 	XDR xdrs;
656 	int error, rcvflag;
657 
658 	/*
659 	 * Serialise access to the socket and our own record parsing
660 	 * state.
661 	 */
662 	sx_xlock(&xprt->xp_lock);
663 
664 	for (;;) {
665 		/* If we have no request ready, check pending queue. */
666 		while (cd->mpending &&
667 		    (cd->mreq == NULL || cd->resid != 0 || !cd->eor)) {
668 			if (!svc_vc_process_pending(xprt))
669 				break;
670 		}
671 
672 		/* Process and return complete request in cd->mreq. */
673 		if (cd->mreq != NULL && cd->resid == 0 && cd->eor) {
674 
675 			xdrmbuf_create(&xdrs, cd->mreq, XDR_DECODE);
676 			cd->mreq = NULL;
677 
678 			/* Check for next request in a pending queue. */
679 			svc_vc_process_pending(xprt);
680 			if (cd->mreq == NULL || cd->resid != 0) {
681 				SOCKBUF_LOCK(&so->so_rcv);
682 				if (!soreadable(so))
683 					xprt_inactive_self(xprt);
684 				SOCKBUF_UNLOCK(&so->so_rcv);
685 			}
686 
687 			sx_xunlock(&xprt->xp_lock);
688 
689 			if (! xdr_callmsg(&xdrs, msg)) {
690 				XDR_DESTROY(&xdrs);
691 				return (FALSE);
692 			}
693 
694 			*addrp = NULL;
695 			*mp = xdrmbuf_getall(&xdrs);
696 			XDR_DESTROY(&xdrs);
697 
698 			return (TRUE);
699 		}
700 
701 		/*
702 		 * The socket upcall calls xprt_active() which will eventually
703 		 * cause the server to call us here. We attempt to
704 		 * read as much as possible from the socket and put
705 		 * the result in cd->mpending. If the read fails,
706 		 * we have drained both cd->mpending and the socket so
707 		 * we can call xprt_inactive().
708 		 */
709 		uio.uio_resid = 1000000000;
710 		uio.uio_td = curthread;
711 		m = NULL;
712 		rcvflag = MSG_DONTWAIT;
713 		error = soreceive(so, NULL, &uio, &m, NULL, &rcvflag);
714 
715 		if (error == EWOULDBLOCK) {
716 			/*
717 			 * We must re-test for readability after
718 			 * taking the lock to protect us in the case
719 			 * where a new packet arrives on the socket
720 			 * after our call to soreceive fails with
721 			 * EWOULDBLOCK.
722 			 */
723 			SOCKBUF_LOCK(&so->so_rcv);
724 			if (!soreadable(so))
725 				xprt_inactive_self(xprt);
726 			SOCKBUF_UNLOCK(&so->so_rcv);
727 			sx_xunlock(&xprt->xp_lock);
728 			return (FALSE);
729 		}
730 
731 		if (error) {
732 			SOCKBUF_LOCK(&so->so_rcv);
733 			if (xprt->xp_upcallset) {
734 				xprt->xp_upcallset = 0;
735 				soupcall_clear(so, SO_RCV);
736 			}
737 			SOCKBUF_UNLOCK(&so->so_rcv);
738 			xprt_inactive_self(xprt);
739 			cd->strm_stat = XPRT_DIED;
740 			sx_xunlock(&xprt->xp_lock);
741 			return (FALSE);
742 		}
743 
744 		if (!m) {
745 			/*
746 			 * EOF - the other end has closed the socket.
747 			 */
748 			xprt_inactive_self(xprt);
749 			cd->strm_stat = XPRT_DIED;
750 			sx_xunlock(&xprt->xp_lock);
751 			return (FALSE);
752 		}
753 
754 		if (cd->mpending)
755 			m_last(cd->mpending)->m_next = m;
756 		else
757 			cd->mpending = m;
758 	}
759 }
760 
761 static bool_t
762 svc_vc_backchannel_recv(SVCXPRT *xprt, struct rpc_msg *msg,
763     struct sockaddr **addrp, struct mbuf **mp)
764 {
765 	struct cf_conn *cd = (struct cf_conn *) xprt->xp_p1;
766 	struct ct_data *ct;
767 	struct mbuf *m;
768 	XDR xdrs;
769 
770 	sx_xlock(&xprt->xp_lock);
771 	ct = (struct ct_data *)xprt->xp_p2;
772 	if (ct == NULL) {
773 		sx_xunlock(&xprt->xp_lock);
774 		return (FALSE);
775 	}
776 	mtx_lock(&ct->ct_lock);
777 	m = cd->mreq;
778 	if (m == NULL) {
779 		xprt_inactive_self(xprt);
780 		mtx_unlock(&ct->ct_lock);
781 		sx_xunlock(&xprt->xp_lock);
782 		return (FALSE);
783 	}
784 	cd->mreq = m->m_nextpkt;
785 	mtx_unlock(&ct->ct_lock);
786 	sx_xunlock(&xprt->xp_lock);
787 
788 	xdrmbuf_create(&xdrs, m, XDR_DECODE);
789 	if (! xdr_callmsg(&xdrs, msg)) {
790 		XDR_DESTROY(&xdrs);
791 		return (FALSE);
792 	}
793 	*addrp = NULL;
794 	*mp = xdrmbuf_getall(&xdrs);
795 	XDR_DESTROY(&xdrs);
796 	return (TRUE);
797 }
798 
799 static bool_t
800 svc_vc_reply(SVCXPRT *xprt, struct rpc_msg *msg,
801     struct sockaddr *addr, struct mbuf *m, uint32_t *seq)
802 {
803 	XDR xdrs;
804 	struct mbuf *mrep;
805 	bool_t stat = TRUE;
806 	int error, len;
807 
808 	/*
809 	 * Leave space for record mark.
810 	 */
811 	mrep = m_gethdr(M_WAITOK, MT_DATA);
812 	mrep->m_data += sizeof(uint32_t);
813 
814 	xdrmbuf_create(&xdrs, mrep, XDR_ENCODE);
815 
816 	if (msg->rm_reply.rp_stat == MSG_ACCEPTED &&
817 	    msg->rm_reply.rp_acpt.ar_stat == SUCCESS) {
818 		if (!xdr_replymsg(&xdrs, msg))
819 			stat = FALSE;
820 		else
821 			xdrmbuf_append(&xdrs, m);
822 	} else {
823 		stat = xdr_replymsg(&xdrs, msg);
824 	}
825 
826 	if (stat) {
827 		m_fixhdr(mrep);
828 
829 		/*
830 		 * Prepend a record marker containing the reply length.
831 		 */
832 		M_PREPEND(mrep, sizeof(uint32_t), M_WAITOK);
833 		len = mrep->m_pkthdr.len;
834 		*mtod(mrep, uint32_t *) =
835 			htonl(0x80000000 | (len - sizeof(uint32_t)));
836 		atomic_add_acq_32(&xprt->xp_snd_cnt, len);
837 		error = sosend(xprt->xp_socket, NULL, NULL, mrep, NULL,
838 		    0, curthread);
839 		if (!error) {
840 			atomic_add_rel_32(&xprt->xp_snt_cnt, len);
841 			if (seq)
842 				*seq = xprt->xp_snd_cnt;
843 			stat = TRUE;
844 		} else
845 			atomic_subtract_32(&xprt->xp_snd_cnt, len);
846 	} else {
847 		m_freem(mrep);
848 	}
849 
850 	XDR_DESTROY(&xdrs);
851 	xprt->xp_p2 = NULL;
852 
853 	return (stat);
854 }
855 
856 static bool_t
857 svc_vc_backchannel_reply(SVCXPRT *xprt, struct rpc_msg *msg,
858     struct sockaddr *addr, struct mbuf *m, uint32_t *seq)
859 {
860 	struct ct_data *ct;
861 	XDR xdrs;
862 	struct mbuf *mrep;
863 	bool_t stat = TRUE;
864 	int error;
865 
866 	/*
867 	 * Leave space for record mark.
868 	 */
869 	mrep = m_gethdr(M_WAITOK, MT_DATA);
870 	mrep->m_data += sizeof(uint32_t);
871 
872 	xdrmbuf_create(&xdrs, mrep, XDR_ENCODE);
873 
874 	if (msg->rm_reply.rp_stat == MSG_ACCEPTED &&
875 	    msg->rm_reply.rp_acpt.ar_stat == SUCCESS) {
876 		if (!xdr_replymsg(&xdrs, msg))
877 			stat = FALSE;
878 		else
879 			xdrmbuf_append(&xdrs, m);
880 	} else {
881 		stat = xdr_replymsg(&xdrs, msg);
882 	}
883 
884 	if (stat) {
885 		m_fixhdr(mrep);
886 
887 		/*
888 		 * Prepend a record marker containing the reply length.
889 		 */
890 		M_PREPEND(mrep, sizeof(uint32_t), M_WAITOK);
891 		*mtod(mrep, uint32_t *) =
892 			htonl(0x80000000 | (mrep->m_pkthdr.len
893 				- sizeof(uint32_t)));
894 		sx_xlock(&xprt->xp_lock);
895 		ct = (struct ct_data *)xprt->xp_p2;
896 		if (ct != NULL)
897 			error = sosend(ct->ct_socket, NULL, NULL, mrep, NULL,
898 			    0, curthread);
899 		else
900 			error = EPIPE;
901 		sx_xunlock(&xprt->xp_lock);
902 		if (!error) {
903 			stat = TRUE;
904 		}
905 	} else {
906 		m_freem(mrep);
907 	}
908 
909 	XDR_DESTROY(&xdrs);
910 
911 	return (stat);
912 }
913 
914 static bool_t
915 svc_vc_null()
916 {
917 
918 	return (FALSE);
919 }
920 
921 static int
922 svc_vc_soupcall(struct socket *so, void *arg, int waitflag)
923 {
924 	SVCXPRT *xprt = (SVCXPRT *) arg;
925 
926 	if (soreadable(xprt->xp_socket))
927 		xprt_active(xprt);
928 	return (SU_OK);
929 }
930 
931 #if 0
932 /*
933  * Get the effective UID of the sending process. Used by rpcbind, keyserv
934  * and rpc.yppasswdd on AF_LOCAL.
935  */
936 int
937 __rpc_get_local_uid(SVCXPRT *transp, uid_t *uid) {
938 	int sock, ret;
939 	gid_t egid;
940 	uid_t euid;
941 	struct sockaddr *sa;
942 
943 	sock = transp->xp_fd;
944 	sa = (struct sockaddr *)transp->xp_rtaddr;
945 	if (sa->sa_family == AF_LOCAL) {
946 		ret = getpeereid(sock, &euid, &egid);
947 		if (ret == 0)
948 			*uid = euid;
949 		return (ret);
950 	} else
951 		return (-1);
952 }
953 #endif
954