xref: /freebsd/sys/rpc/svc_vc.c (revision caf6fbd81a21a5bd5fac57a0163582bbc8968920)
1 /*	$NetBSD: svc_vc.c,v 1.7 2000/08/03 00:01:53 fvdl Exp $	*/
2 
3 /*
4  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
5  * unrestricted use provided that this legend is included on all tape
6  * media and as a part of the software program in whole or part.  Users
7  * may copy or modify Sun RPC without charge, but are not authorized
8  * to license or distribute it to anyone else except as part of a product or
9  * program developed by the user.
10  *
11  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
12  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
13  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
14  *
15  * Sun RPC is provided with no support and without any obligation on the
16  * part of Sun Microsystems, Inc. to assist in its use, correction,
17  * modification or enhancement.
18  *
19  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
20  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
21  * OR ANY PART THEREOF.
22  *
23  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
24  * or profits or other special, indirect and consequential damages, even if
25  * Sun has been advised of the possibility of such damages.
26  *
27  * Sun Microsystems, Inc.
28  * 2550 Garcia Avenue
29  * Mountain View, California  94043
30  */
31 
32 #if defined(LIBC_SCCS) && !defined(lint)
33 static char *sccsid2 = "@(#)svc_tcp.c 1.21 87/08/11 Copyr 1984 Sun Micro";
34 static char *sccsid = "@(#)svc_tcp.c	2.2 88/08/01 4.0 RPCSRC";
35 #endif
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38 
39 /*
40  * svc_vc.c, Server side for Connection Oriented based RPC.
41  *
42  * Actually implements two flavors of transporter -
43  * a tcp rendezvouser (a listner and connection establisher)
44  * and a record/tcp stream.
45  */
46 
47 #include <sys/param.h>
48 #include <sys/lock.h>
49 #include <sys/kernel.h>
50 #include <sys/malloc.h>
51 #include <sys/mbuf.h>
52 #include <sys/mutex.h>
53 #include <sys/proc.h>
54 #include <sys/protosw.h>
55 #include <sys/queue.h>
56 #include <sys/socket.h>
57 #include <sys/socketvar.h>
58 #include <sys/sx.h>
59 #include <sys/systm.h>
60 #include <sys/uio.h>
61 
62 #include <net/vnet.h>
63 
64 #include <netinet/tcp.h>
65 
66 #include <rpc/rpc.h>
67 
68 #include <rpc/krpc.h>
69 #include <rpc/rpc_com.h>
70 
71 #include <security/mac/mac_framework.h>
72 
73 static bool_t svc_vc_rendezvous_recv(SVCXPRT *, struct rpc_msg *,
74     struct sockaddr **, struct mbuf **);
75 static enum xprt_stat svc_vc_rendezvous_stat(SVCXPRT *);
76 static void svc_vc_rendezvous_destroy(SVCXPRT *);
77 static bool_t svc_vc_null(void);
78 static void svc_vc_destroy(SVCXPRT *);
79 static enum xprt_stat svc_vc_stat(SVCXPRT *);
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 *);
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 *);
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 *))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_reply =	svc_vc_reply,
113 	.xp_destroy =	svc_vc_destroy,
114 	.xp_control =	svc_vc_control
115 };
116 
117 static struct xp_ops svc_vc_backchannel_ops = {
118 	.xp_recv =	svc_vc_backchannel_recv,
119 	.xp_stat =	svc_vc_backchannel_stat,
120 	.xp_reply =	svc_vc_backchannel_reply,
121 	.xp_destroy =	svc_vc_backchannel_destroy,
122 	.xp_control =	svc_vc_backchannel_control
123 };
124 
125 /*
126  * Usage:
127  *	xprt = svc_vc_create(sock, send_buf_size, recv_buf_size);
128  *
129  * Creates, registers, and returns a (rpc) tcp based transporter.
130  * Once *xprt is initialized, it is registered as a transporter
131  * see (svc.h, xprt_register).  This routine returns
132  * a NULL if a problem occurred.
133  *
134  * The filedescriptor passed in is expected to refer to a bound, but
135  * not yet connected socket.
136  *
137  * Since streams do buffered io similar to stdio, the caller can specify
138  * how big the send and receive buffers are via the second and third parms;
139  * 0 => use the system default.
140  */
141 SVCXPRT *
142 svc_vc_create(SVCPOOL *pool, struct socket *so, size_t sendsize,
143     size_t recvsize)
144 {
145 	SVCXPRT *xprt;
146 	struct sockaddr* sa;
147 	int error;
148 
149 	SOCK_LOCK(so);
150 	if (so->so_state & (SS_ISCONNECTED|SS_ISDISCONNECTED)) {
151 		SOCK_UNLOCK(so);
152 		error = so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa);
153 		if (error)
154 			return (NULL);
155 		xprt = svc_vc_create_conn(pool, so, sa);
156 		free(sa, M_SONAME);
157 		return (xprt);
158 	}
159 	SOCK_UNLOCK(so);
160 
161 	xprt = svc_xprt_alloc();
162 	sx_init(&xprt->xp_lock, "xprt->xp_lock");
163 	xprt->xp_pool = pool;
164 	xprt->xp_socket = so;
165 	xprt->xp_p1 = NULL;
166 	xprt->xp_p2 = NULL;
167 	xprt->xp_ops = &svc_vc_rendezvous_ops;
168 
169 	error = so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa);
170 	if (error) {
171 		goto cleanup_svc_vc_create;
172 	}
173 
174 	memcpy(&xprt->xp_ltaddr, sa, sa->sa_len);
175 	free(sa, M_SONAME);
176 
177 	xprt_register(xprt);
178 
179 	solisten(so, SOMAXCONN, curthread);
180 
181 	SOCKBUF_LOCK(&so->so_rcv);
182 	xprt->xp_upcallset = 1;
183 	soupcall_set(so, SO_RCV, svc_vc_soupcall, xprt);
184 	SOCKBUF_UNLOCK(&so->so_rcv);
185 
186 	return (xprt);
187 cleanup_svc_vc_create:
188 	if (xprt)
189 		svc_xprt_free(xprt);
190 	return (NULL);
191 }
192 
193 /*
194  * Create a new transport for a socket optained via soaccept().
195  */
196 SVCXPRT *
197 svc_vc_create_conn(SVCPOOL *pool, struct socket *so, struct sockaddr *raddr)
198 {
199 	SVCXPRT *xprt = NULL;
200 	struct cf_conn *cd = NULL;
201 	struct sockaddr* sa = NULL;
202 	struct sockopt opt;
203 	int one = 1;
204 	int error;
205 
206 	bzero(&opt, sizeof(struct sockopt));
207 	opt.sopt_dir = SOPT_SET;
208 	opt.sopt_level = SOL_SOCKET;
209 	opt.sopt_name = SO_KEEPALIVE;
210 	opt.sopt_val = &one;
211 	opt.sopt_valsize = sizeof(one);
212 	error = sosetopt(so, &opt);
213 	if (error) {
214 		return (NULL);
215 	}
216 
217 	if (so->so_proto->pr_protocol == IPPROTO_TCP) {
218 		bzero(&opt, sizeof(struct sockopt));
219 		opt.sopt_dir = SOPT_SET;
220 		opt.sopt_level = IPPROTO_TCP;
221 		opt.sopt_name = TCP_NODELAY;
222 		opt.sopt_val = &one;
223 		opt.sopt_valsize = sizeof(one);
224 		error = sosetopt(so, &opt);
225 		if (error) {
226 			return (NULL);
227 		}
228 	}
229 
230 	cd = mem_alloc(sizeof(*cd));
231 	cd->strm_stat = XPRT_IDLE;
232 
233 	xprt = svc_xprt_alloc();
234 	sx_init(&xprt->xp_lock, "xprt->xp_lock");
235 	xprt->xp_pool = pool;
236 	xprt->xp_socket = so;
237 	xprt->xp_p1 = cd;
238 	xprt->xp_p2 = NULL;
239 	xprt->xp_ops = &svc_vc_ops;
240 
241 	/*
242 	 * See http://www.connectathon.org/talks96/nfstcp.pdf - client
243 	 * has a 5 minute timer, server has a 6 minute timer.
244 	 */
245 	xprt->xp_idletimeout = 6 * 60;
246 
247 	memcpy(&xprt->xp_rtaddr, raddr, raddr->sa_len);
248 
249 	error = so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa);
250 	if (error)
251 		goto cleanup_svc_vc_create;
252 
253 	memcpy(&xprt->xp_ltaddr, sa, sa->sa_len);
254 	free(sa, M_SONAME);
255 
256 	xprt_register(xprt);
257 
258 	SOCKBUF_LOCK(&so->so_rcv);
259 	xprt->xp_upcallset = 1;
260 	soupcall_set(so, SO_RCV, svc_vc_soupcall, xprt);
261 	SOCKBUF_UNLOCK(&so->so_rcv);
262 
263 	/*
264 	 * Throw the transport into the active list in case it already
265 	 * has some data buffered.
266 	 */
267 	sx_xlock(&xprt->xp_lock);
268 	xprt_active(xprt);
269 	sx_xunlock(&xprt->xp_lock);
270 
271 	return (xprt);
272 cleanup_svc_vc_create:
273 	if (xprt) {
274 		mem_free(xprt, sizeof(*xprt));
275 	}
276 	if (cd)
277 		mem_free(cd, sizeof(*cd));
278 	return (NULL);
279 }
280 
281 /*
282  * Create a new transport for a backchannel on a clnt_vc socket.
283  */
284 SVCXPRT *
285 svc_vc_create_backchannel(SVCPOOL *pool)
286 {
287 	SVCXPRT *xprt = NULL;
288 	struct cf_conn *cd = NULL;
289 
290 	cd = mem_alloc(sizeof(*cd));
291 	cd->strm_stat = XPRT_IDLE;
292 
293 	xprt = svc_xprt_alloc();
294 	sx_init(&xprt->xp_lock, "xprt->xp_lock");
295 	xprt->xp_pool = pool;
296 	xprt->xp_socket = NULL;
297 	xprt->xp_p1 = cd;
298 	xprt->xp_p2 = NULL;
299 	xprt->xp_ops = &svc_vc_backchannel_ops;
300 	return (xprt);
301 }
302 
303 /*
304  * This does all of the accept except the final call to soaccept. The
305  * caller will call soaccept after dropping its locks (soaccept may
306  * call malloc).
307  */
308 int
309 svc_vc_accept(struct socket *head, struct socket **sop)
310 {
311 	int error = 0;
312 	struct socket *so;
313 
314 	if ((head->so_options & SO_ACCEPTCONN) == 0) {
315 		error = EINVAL;
316 		goto done;
317 	}
318 #ifdef MAC
319 	error = mac_socket_check_accept(curthread->td_ucred, head);
320 	if (error != 0)
321 		goto done;
322 #endif
323 	ACCEPT_LOCK();
324 	if (TAILQ_EMPTY(&head->so_comp)) {
325 		ACCEPT_UNLOCK();
326 		error = EWOULDBLOCK;
327 		goto done;
328 	}
329 	so = TAILQ_FIRST(&head->so_comp);
330 	KASSERT(!(so->so_qstate & SQ_INCOMP), ("svc_vc_accept: so SQ_INCOMP"));
331 	KASSERT(so->so_qstate & SQ_COMP, ("svc_vc_accept: so not SQ_COMP"));
332 
333 	/*
334 	 * Before changing the flags on the socket, we have to bump the
335 	 * reference count.  Otherwise, if the protocol calls sofree(),
336 	 * the socket will be released due to a zero refcount.
337 	 * XXX might not need soref() since this is simpler than kern_accept.
338 	 */
339 	SOCK_LOCK(so);			/* soref() and so_state update */
340 	soref(so);			/* file descriptor reference */
341 
342 	TAILQ_REMOVE(&head->so_comp, so, so_list);
343 	head->so_qlen--;
344 	so->so_state |= (head->so_state & SS_NBIO);
345 	so->so_qstate &= ~SQ_COMP;
346 	so->so_head = NULL;
347 
348 	SOCK_UNLOCK(so);
349 	ACCEPT_UNLOCK();
350 
351 	*sop = so;
352 
353 	/* connection has been removed from the listen queue */
354 	KNOTE_UNLOCKED(&head->so_rcv.sb_sel.si_note, 0);
355 done:
356 	return (error);
357 }
358 
359 /*ARGSUSED*/
360 static bool_t
361 svc_vc_rendezvous_recv(SVCXPRT *xprt, struct rpc_msg *msg,
362     struct sockaddr **addrp, struct mbuf **mp)
363 {
364 	struct socket *so = NULL;
365 	struct sockaddr *sa = NULL;
366 	int error;
367 	SVCXPRT *new_xprt;
368 
369 	/*
370 	 * The socket upcall calls xprt_active() which will eventually
371 	 * cause the server to call us here. We attempt to accept a
372 	 * connection from the socket and turn it into a new
373 	 * transport. If the accept fails, we have drained all pending
374 	 * connections so we call xprt_inactive().
375 	 */
376 	sx_xlock(&xprt->xp_lock);
377 
378 	error = svc_vc_accept(xprt->xp_socket, &so);
379 
380 	if (error == EWOULDBLOCK) {
381 		/*
382 		 * We must re-test for new connections after taking
383 		 * the lock to protect us in the case where a new
384 		 * connection arrives after our call to accept fails
385 		 * with EWOULDBLOCK. The pool lock protects us from
386 		 * racing the upcall after our TAILQ_EMPTY() call
387 		 * returns false.
388 		 */
389 		ACCEPT_LOCK();
390 		mtx_lock(&xprt->xp_pool->sp_lock);
391 		if (TAILQ_EMPTY(&xprt->xp_socket->so_comp))
392 			xprt_inactive_locked(xprt);
393 		mtx_unlock(&xprt->xp_pool->sp_lock);
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(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 	sx_destroy(&xprt->xp_lock);
460 	if (xprt->xp_socket)
461 		(void)soclose(xprt->xp_socket);
462 
463 	if (xprt->xp_netid)
464 		(void) mem_free(xprt->xp_netid, strlen(xprt->xp_netid) + 1);
465 	svc_xprt_free(xprt);
466 }
467 
468 static void
469 svc_vc_rendezvous_destroy(SVCXPRT *xprt)
470 {
471 
472 	svc_vc_destroy_common(xprt);
473 }
474 
475 static void
476 svc_vc_destroy(SVCXPRT *xprt)
477 {
478 	struct cf_conn *cd = (struct cf_conn *)xprt->xp_p1;
479 
480 	svc_vc_destroy_common(xprt);
481 
482 	if (cd->mreq)
483 		m_freem(cd->mreq);
484 	if (cd->mpending)
485 		m_freem(cd->mpending);
486 	mem_free(cd, sizeof(*cd));
487 }
488 
489 static void
490 svc_vc_backchannel_destroy(SVCXPRT *xprt)
491 {
492 	struct cf_conn *cd = (struct cf_conn *)xprt->xp_p1;
493 	struct mbuf *m, *m2;
494 
495 	svc_xprt_free(xprt);
496 	m = cd->mreq;
497 	while (m != NULL) {
498 		m2 = m;
499 		m = m->m_nextpkt;
500 		m_freem(m2);
501 	}
502 	mem_free(cd, sizeof(*cd));
503 }
504 
505 /*ARGSUSED*/
506 static bool_t
507 svc_vc_control(SVCXPRT *xprt, const u_int rq, void *in)
508 {
509 	return (FALSE);
510 }
511 
512 static bool_t
513 svc_vc_rendezvous_control(SVCXPRT *xprt, const u_int rq, void *in)
514 {
515 
516 	return (FALSE);
517 }
518 
519 static bool_t
520 svc_vc_backchannel_control(SVCXPRT *xprt, const u_int rq, void *in)
521 {
522 
523 	return (FALSE);
524 }
525 
526 static enum xprt_stat
527 svc_vc_stat(SVCXPRT *xprt)
528 {
529 	struct cf_conn *cd;
530 	struct mbuf *m;
531 	size_t n;
532 
533 	cd = (struct cf_conn *)(xprt->xp_p1);
534 
535 	if (cd->strm_stat == XPRT_DIED)
536 		return (XPRT_DIED);
537 
538 	/*
539 	 * Return XPRT_MOREREQS if we have buffered data and we are
540 	 * mid-record or if we have enough data for a record
541 	 * marker. Since this is only a hint, we read mpending and
542 	 * resid outside the lock. We do need to take the lock if we
543 	 * have to traverse the mbuf chain.
544 	 */
545 	if (cd->mpending) {
546 		if (cd->resid)
547 			return (XPRT_MOREREQS);
548 		n = 0;
549 		sx_xlock(&xprt->xp_lock);
550 		m = cd->mpending;
551 		while (m && n < sizeof(uint32_t)) {
552 			n += m->m_len;
553 			m = m->m_next;
554 		}
555 		sx_xunlock(&xprt->xp_lock);
556 		if (n >= sizeof(uint32_t))
557 			return (XPRT_MOREREQS);
558 	}
559 
560 	if (soreadable(xprt->xp_socket))
561 		return (XPRT_MOREREQS);
562 
563 	return (XPRT_IDLE);
564 }
565 
566 static enum xprt_stat
567 svc_vc_backchannel_stat(SVCXPRT *xprt)
568 {
569 	struct cf_conn *cd;
570 
571 	cd = (struct cf_conn *)(xprt->xp_p1);
572 
573 	if (cd->mreq != NULL)
574 		return (XPRT_MOREREQS);
575 
576 	return (XPRT_IDLE);
577 }
578 
579 static bool_t
580 svc_vc_recv(SVCXPRT *xprt, struct rpc_msg *msg,
581     struct sockaddr **addrp, struct mbuf **mp)
582 {
583 	struct cf_conn *cd = (struct cf_conn *) xprt->xp_p1;
584 	struct uio uio;
585 	struct mbuf *m;
586 	XDR xdrs;
587 	int error, rcvflag;
588 
589 	/*
590 	 * Serialise access to the socket and our own record parsing
591 	 * state.
592 	 */
593 	sx_xlock(&xprt->xp_lock);
594 
595 	for (;;) {
596 		/*
597 		 * If we have an mbuf chain in cd->mpending, try to parse a
598 		 * record from it, leaving the result in cd->mreq. If we don't
599 		 * have a complete record, leave the partial result in
600 		 * cd->mreq and try to read more from the socket.
601 		 */
602 		if (cd->mpending) {
603 			/*
604 			 * If cd->resid is non-zero, we have part of the
605 			 * record already, otherwise we are expecting a record
606 			 * marker.
607 			 */
608 			if (!cd->resid) {
609 				/*
610 				 * See if there is enough data buffered to
611 				 * make up a record marker. Make sure we can
612 				 * handle the case where the record marker is
613 				 * split across more than one mbuf.
614 				 */
615 				size_t n = 0;
616 				uint32_t header;
617 
618 				m = cd->mpending;
619 				while (n < sizeof(uint32_t) && m) {
620 					n += m->m_len;
621 					m = m->m_next;
622 				}
623 				if (n < sizeof(uint32_t))
624 					goto readmore;
625 				m_copydata(cd->mpending, 0, sizeof(header),
626 				    (char *)&header);
627 				header = ntohl(header);
628 				cd->eor = (header & 0x80000000) != 0;
629 				cd->resid = header & 0x7fffffff;
630 				m_adj(cd->mpending, sizeof(uint32_t));
631 			}
632 
633 			/*
634 			 * Start pulling off mbufs from cd->mpending
635 			 * until we either have a complete record or
636 			 * we run out of data. We use m_split to pull
637 			 * data - it will pull as much as possible and
638 			 * split the last mbuf if necessary.
639 			 */
640 			while (cd->mpending && cd->resid) {
641 				m = cd->mpending;
642 				if (cd->mpending->m_next
643 				    || cd->mpending->m_len > cd->resid)
644 					cd->mpending = m_split(cd->mpending,
645 					    cd->resid, M_WAITOK);
646 				else
647 					cd->mpending = NULL;
648 				if (cd->mreq)
649 					m_last(cd->mreq)->m_next = m;
650 				else
651 					cd->mreq = m;
652 				while (m) {
653 					cd->resid -= m->m_len;
654 					m = m->m_next;
655 				}
656 			}
657 
658 			/*
659 			 * If cd->resid is zero now, we have managed to
660 			 * receive a record fragment from the stream. Check
661 			 * for the end-of-record mark to see if we need more.
662 			 */
663 			if (cd->resid == 0) {
664 				if (!cd->eor)
665 					continue;
666 
667 				/*
668 				 * Success - we have a complete record in
669 				 * cd->mreq.
670 				 */
671 				xdrmbuf_create(&xdrs, cd->mreq, XDR_DECODE);
672 				cd->mreq = NULL;
673 				sx_xunlock(&xprt->xp_lock);
674 
675 				if (! xdr_callmsg(&xdrs, msg)) {
676 					XDR_DESTROY(&xdrs);
677 					return (FALSE);
678 				}
679 
680 				*addrp = NULL;
681 				*mp = xdrmbuf_getall(&xdrs);
682 				XDR_DESTROY(&xdrs);
683 
684 				return (TRUE);
685 			}
686 		}
687 
688 	readmore:
689 		/*
690 		 * The socket upcall calls xprt_active() which will eventually
691 		 * cause the server to call us here. We attempt to
692 		 * read as much as possible from the socket and put
693 		 * the result in cd->mpending. If the read fails,
694 		 * we have drained both cd->mpending and the socket so
695 		 * we can call xprt_inactive().
696 		 */
697 		uio.uio_resid = 1000000000;
698 		uio.uio_td = curthread;
699 		m = NULL;
700 		rcvflag = MSG_DONTWAIT;
701 		error = soreceive(xprt->xp_socket, NULL, &uio, &m, NULL,
702 		    &rcvflag);
703 
704 		if (error == EWOULDBLOCK) {
705 			/*
706 			 * We must re-test for readability after
707 			 * taking the lock to protect us in the case
708 			 * where a new packet arrives on the socket
709 			 * after our call to soreceive fails with
710 			 * EWOULDBLOCK. The pool lock protects us from
711 			 * racing the upcall after our soreadable()
712 			 * call returns false.
713 			 */
714 			mtx_lock(&xprt->xp_pool->sp_lock);
715 			if (!soreadable(xprt->xp_socket))
716 				xprt_inactive_locked(xprt);
717 			mtx_unlock(&xprt->xp_pool->sp_lock);
718 			sx_xunlock(&xprt->xp_lock);
719 			return (FALSE);
720 		}
721 
722 		if (error) {
723 			SOCKBUF_LOCK(&xprt->xp_socket->so_rcv);
724 			if (xprt->xp_upcallset) {
725 				xprt->xp_upcallset = 0;
726 				soupcall_clear(xprt->xp_socket, SO_RCV);
727 			}
728 			SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv);
729 			xprt_inactive(xprt);
730 			cd->strm_stat = XPRT_DIED;
731 			sx_xunlock(&xprt->xp_lock);
732 			return (FALSE);
733 		}
734 
735 		if (!m) {
736 			/*
737 			 * EOF - the other end has closed the socket.
738 			 */
739 			xprt_inactive(xprt);
740 			cd->strm_stat = XPRT_DIED;
741 			sx_xunlock(&xprt->xp_lock);
742 			return (FALSE);
743 		}
744 
745 		if (cd->mpending)
746 			m_last(cd->mpending)->m_next = m;
747 		else
748 			cd->mpending = m;
749 	}
750 }
751 
752 static bool_t
753 svc_vc_backchannel_recv(SVCXPRT *xprt, struct rpc_msg *msg,
754     struct sockaddr **addrp, struct mbuf **mp)
755 {
756 	struct cf_conn *cd = (struct cf_conn *) xprt->xp_p1;
757 	struct ct_data *ct;
758 	struct mbuf *m;
759 	XDR xdrs;
760 
761 	sx_xlock(&xprt->xp_lock);
762 	ct = (struct ct_data *)xprt->xp_p2;
763 	if (ct == NULL) {
764 		sx_xunlock(&xprt->xp_lock);
765 		return (FALSE);
766 	}
767 	mtx_lock(&ct->ct_lock);
768 	m = cd->mreq;
769 	if (m == NULL) {
770 		xprt_inactive(xprt);
771 		mtx_unlock(&ct->ct_lock);
772 		sx_xunlock(&xprt->xp_lock);
773 		return (FALSE);
774 	}
775 	cd->mreq = m->m_nextpkt;
776 	mtx_unlock(&ct->ct_lock);
777 	sx_xunlock(&xprt->xp_lock);
778 
779 	xdrmbuf_create(&xdrs, m, XDR_DECODE);
780 	if (! xdr_callmsg(&xdrs, msg)) {
781 		XDR_DESTROY(&xdrs);
782 		return (FALSE);
783 	}
784 	*addrp = NULL;
785 	*mp = xdrmbuf_getall(&xdrs);
786 	XDR_DESTROY(&xdrs);
787 	return (TRUE);
788 }
789 
790 static bool_t
791 svc_vc_reply(SVCXPRT *xprt, struct rpc_msg *msg,
792     struct sockaddr *addr, struct mbuf *m)
793 {
794 	XDR xdrs;
795 	struct mbuf *mrep;
796 	bool_t stat = TRUE;
797 	int error;
798 
799 	/*
800 	 * Leave space for record mark.
801 	 */
802 	mrep = m_gethdr(M_WAITOK, MT_DATA);
803 	mrep->m_data += sizeof(uint32_t);
804 
805 	xdrmbuf_create(&xdrs, mrep, XDR_ENCODE);
806 
807 	if (msg->rm_reply.rp_stat == MSG_ACCEPTED &&
808 	    msg->rm_reply.rp_acpt.ar_stat == SUCCESS) {
809 		if (!xdr_replymsg(&xdrs, msg))
810 			stat = FALSE;
811 		else
812 			xdrmbuf_append(&xdrs, m);
813 	} else {
814 		stat = xdr_replymsg(&xdrs, msg);
815 	}
816 
817 	if (stat) {
818 		m_fixhdr(mrep);
819 
820 		/*
821 		 * Prepend a record marker containing the reply length.
822 		 */
823 		M_PREPEND(mrep, sizeof(uint32_t), M_WAITOK);
824 		*mtod(mrep, uint32_t *) =
825 			htonl(0x80000000 | (mrep->m_pkthdr.len
826 				- sizeof(uint32_t)));
827 		error = sosend(xprt->xp_socket, NULL, NULL, mrep, NULL,
828 		    0, curthread);
829 		if (!error) {
830 			stat = TRUE;
831 		}
832 	} else {
833 		m_freem(mrep);
834 	}
835 
836 	XDR_DESTROY(&xdrs);
837 	xprt->xp_p2 = NULL;
838 
839 	return (stat);
840 }
841 
842 static bool_t
843 svc_vc_backchannel_reply(SVCXPRT *xprt, struct rpc_msg *msg,
844     struct sockaddr *addr, struct mbuf *m)
845 {
846 	struct ct_data *ct;
847 	XDR xdrs;
848 	struct mbuf *mrep;
849 	bool_t stat = TRUE;
850 	int error;
851 
852 	/*
853 	 * Leave space for record mark.
854 	 */
855 	mrep = m_gethdr(M_WAITOK, MT_DATA);
856 	mrep->m_data += sizeof(uint32_t);
857 
858 	xdrmbuf_create(&xdrs, mrep, XDR_ENCODE);
859 
860 	if (msg->rm_reply.rp_stat == MSG_ACCEPTED &&
861 	    msg->rm_reply.rp_acpt.ar_stat == SUCCESS) {
862 		if (!xdr_replymsg(&xdrs, msg))
863 			stat = FALSE;
864 		else
865 			xdrmbuf_append(&xdrs, m);
866 	} else {
867 		stat = xdr_replymsg(&xdrs, msg);
868 	}
869 
870 	if (stat) {
871 		m_fixhdr(mrep);
872 
873 		/*
874 		 * Prepend a record marker containing the reply length.
875 		 */
876 		M_PREPEND(mrep, sizeof(uint32_t), M_WAITOK);
877 		*mtod(mrep, uint32_t *) =
878 			htonl(0x80000000 | (mrep->m_pkthdr.len
879 				- sizeof(uint32_t)));
880 		sx_xlock(&xprt->xp_lock);
881 		ct = (struct ct_data *)xprt->xp_p2;
882 		if (ct != NULL)
883 			error = sosend(ct->ct_socket, NULL, NULL, mrep, NULL,
884 			    0, curthread);
885 		else
886 			error = EPIPE;
887 		sx_xunlock(&xprt->xp_lock);
888 		if (!error) {
889 			stat = TRUE;
890 		}
891 	} else {
892 		m_freem(mrep);
893 	}
894 
895 	XDR_DESTROY(&xdrs);
896 
897 	return (stat);
898 }
899 
900 static bool_t
901 svc_vc_null()
902 {
903 
904 	return (FALSE);
905 }
906 
907 static int
908 svc_vc_soupcall(struct socket *so, void *arg, int waitflag)
909 {
910 	SVCXPRT *xprt = (SVCXPRT *) arg;
911 
912 	xprt_active(xprt);
913 	return (SU_OK);
914 }
915 
916 #if 0
917 /*
918  * Get the effective UID of the sending process. Used by rpcbind, keyserv
919  * and rpc.yppasswdd on AF_LOCAL.
920  */
921 int
922 __rpc_get_local_uid(SVCXPRT *transp, uid_t *uid) {
923 	int sock, ret;
924 	gid_t egid;
925 	uid_t euid;
926 	struct sockaddr *sa;
927 
928 	sock = transp->xp_fd;
929 	sa = (struct sockaddr *)transp->xp_rtaddr;
930 	if (sa->sa_family == AF_LOCAL) {
931 		ret = getpeereid(sock, &euid, &egid);
932 		if (ret == 0)
933 			*uid = euid;
934 		return (ret);
935 	} else
936 		return (-1);
937 }
938 #endif
939