xref: /freebsd/sys/rpc/svc_vc.c (revision cacdd70cc751fb68dec4b86c5e5b8c969b6e26ef)
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/protosw.h>
54 #include <sys/queue.h>
55 #include <sys/socket.h>
56 #include <sys/socketvar.h>
57 #include <sys/systm.h>
58 #include <sys/uio.h>
59 #include <netinet/tcp.h>
60 
61 #include <rpc/rpc.h>
62 
63 #include <rpc/rpc_com.h>
64 
65 static bool_t svc_vc_rendezvous_recv(SVCXPRT *, struct rpc_msg *);
66 static enum xprt_stat svc_vc_rendezvous_stat(SVCXPRT *);
67 static void svc_vc_rendezvous_destroy(SVCXPRT *);
68 static bool_t svc_vc_null(void);
69 static void svc_vc_destroy(SVCXPRT *);
70 static enum xprt_stat svc_vc_stat(SVCXPRT *);
71 static bool_t svc_vc_recv(SVCXPRT *, struct rpc_msg *);
72 static bool_t svc_vc_getargs(SVCXPRT *, xdrproc_t, void *);
73 static bool_t svc_vc_freeargs(SVCXPRT *, xdrproc_t, void *);
74 static bool_t svc_vc_reply(SVCXPRT *, struct rpc_msg *);
75 static bool_t svc_vc_control(SVCXPRT *xprt, const u_int rq, void *in);
76 static bool_t svc_vc_rendezvous_control (SVCXPRT *xprt, const u_int rq,
77     void *in);
78 static SVCXPRT *svc_vc_create_conn(SVCPOOL *pool, struct socket *so,
79     struct sockaddr *raddr);
80 static int svc_vc_accept(struct socket *head, struct socket **sop);
81 static void svc_vc_soupcall(struct socket *so, void *arg, int waitflag);
82 
83 static struct xp_ops svc_vc_rendezvous_ops = {
84 	.xp_recv =	svc_vc_rendezvous_recv,
85 	.xp_stat =	svc_vc_rendezvous_stat,
86 	.xp_getargs =	(bool_t (*)(SVCXPRT *, xdrproc_t, void *))svc_vc_null,
87 	.xp_reply =	(bool_t (*)(SVCXPRT *, struct rpc_msg *))svc_vc_null,
88 	.xp_freeargs =	(bool_t (*)(SVCXPRT *, xdrproc_t, void *))svc_vc_null,
89 	.xp_destroy =	svc_vc_rendezvous_destroy,
90 	.xp_control =	svc_vc_rendezvous_control
91 };
92 
93 static struct xp_ops svc_vc_ops = {
94 	.xp_recv =	svc_vc_recv,
95 	.xp_stat =	svc_vc_stat,
96 	.xp_getargs =	svc_vc_getargs,
97 	.xp_reply =	svc_vc_reply,
98 	.xp_freeargs =	svc_vc_freeargs,
99 	.xp_destroy =	svc_vc_destroy,
100 	.xp_control =	svc_vc_control
101 };
102 
103 struct cf_conn {  /* kept in xprt->xp_p1 for actual connection */
104 	enum xprt_stat strm_stat;
105 	struct mbuf *mpending;	/* unparsed data read from the socket */
106 	struct mbuf *mreq;	/* current record being built from mpending */
107 	uint32_t resid;		/* number of bytes needed for fragment */
108 	bool_t eor;		/* reading last fragment of current record */
109 };
110 
111 /*
112  * Usage:
113  *	xprt = svc_vc_create(sock, send_buf_size, recv_buf_size);
114  *
115  * Creates, registers, and returns a (rpc) tcp based transporter.
116  * Once *xprt is initialized, it is registered as a transporter
117  * see (svc.h, xprt_register).  This routine returns
118  * a NULL if a problem occurred.
119  *
120  * The filedescriptor passed in is expected to refer to a bound, but
121  * not yet connected socket.
122  *
123  * Since streams do buffered io similar to stdio, the caller can specify
124  * how big the send and receive buffers are via the second and third parms;
125  * 0 => use the system default.
126  */
127 SVCXPRT *
128 svc_vc_create(SVCPOOL *pool, struct socket *so, size_t sendsize,
129     size_t recvsize)
130 {
131 	SVCXPRT *xprt;
132 	struct sockaddr* sa;
133 	int error;
134 
135 	if (so->so_state & SS_ISCONNECTED) {
136 		error = so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa);
137 		if (error)
138 			return (NULL);
139 		xprt = svc_vc_create_conn(pool, so, sa);
140 		free(sa, M_SONAME);
141 		return (xprt);
142 	}
143 
144 	xprt = mem_alloc(sizeof(SVCXPRT));
145 	mtx_init(&xprt->xp_lock, "xprt->xp_lock", NULL, MTX_DEF);
146 	xprt->xp_pool = pool;
147 	xprt->xp_socket = so;
148 	xprt->xp_p1 = NULL;
149 	xprt->xp_p2 = NULL;
150 	xprt->xp_p3 = NULL;
151 	xprt->xp_verf = _null_auth;
152 	xprt->xp_ops = &svc_vc_rendezvous_ops;
153 
154 	error = so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa);
155 	if (error)
156 		goto cleanup_svc_vc_create;
157 
158 	xprt->xp_ltaddr.buf = mem_alloc(sizeof (struct sockaddr_storage));
159 	xprt->xp_ltaddr.maxlen = sizeof (struct sockaddr_storage);
160 	xprt->xp_ltaddr.len = sa->sa_len;
161 	memcpy(xprt->xp_ltaddr.buf, sa, sa->sa_len);
162 	free(sa, M_SONAME);
163 
164 	xprt->xp_rtaddr.maxlen = 0;
165 
166 	xprt_register(xprt);
167 
168 	solisten(so, SOMAXCONN, curthread);
169 
170 	SOCKBUF_LOCK(&so->so_rcv);
171 	so->so_upcallarg = xprt;
172 	so->so_upcall = svc_vc_soupcall;
173 	so->so_rcv.sb_flags |= SB_UPCALL;
174 	SOCKBUF_UNLOCK(&so->so_rcv);
175 
176 	return (xprt);
177 cleanup_svc_vc_create:
178 	if (xprt)
179 		mem_free(xprt, sizeof(*xprt));
180 	return (NULL);
181 }
182 
183 /*
184  * Create a new transport for a socket optained via soaccept().
185  */
186 SVCXPRT *
187 svc_vc_create_conn(SVCPOOL *pool, struct socket *so, struct sockaddr *raddr)
188 {
189 	SVCXPRT *xprt = NULL;
190 	struct cf_conn *cd = NULL;
191 	struct sockaddr* sa = NULL;
192 	struct sockopt opt;
193 	int one = 1;
194 	int error;
195 
196 	bzero(&opt, sizeof(struct sockopt));
197 	opt.sopt_dir = SOPT_SET;
198 	opt.sopt_level = SOL_SOCKET;
199 	opt.sopt_name = SO_KEEPALIVE;
200 	opt.sopt_val = &one;
201 	opt.sopt_valsize = sizeof(one);
202 	error = sosetopt(so, &opt);
203 	if (error)
204 		return (NULL);
205 
206 	if (so->so_proto->pr_protocol == IPPROTO_TCP) {
207 		bzero(&opt, sizeof(struct sockopt));
208 		opt.sopt_dir = SOPT_SET;
209 		opt.sopt_level = IPPROTO_TCP;
210 		opt.sopt_name = TCP_NODELAY;
211 		opt.sopt_val = &one;
212 		opt.sopt_valsize = sizeof(one);
213 		error = sosetopt(so, &opt);
214 		if (error)
215 			return (NULL);
216 	}
217 
218 	cd = mem_alloc(sizeof(*cd));
219 	cd->strm_stat = XPRT_IDLE;
220 
221 	xprt = mem_alloc(sizeof(SVCXPRT));
222 	mtx_init(&xprt->xp_lock, "xprt->xp_lock", NULL, MTX_DEF);
223 	xprt->xp_pool = pool;
224 	xprt->xp_socket = so;
225 	xprt->xp_p1 = cd;
226 	xprt->xp_p2 = NULL;
227 	xprt->xp_p3 = NULL;
228 	xprt->xp_verf = _null_auth;
229 	xprt->xp_ops = &svc_vc_ops;
230 
231 	xprt->xp_rtaddr.buf = mem_alloc(sizeof (struct sockaddr_storage));
232 	xprt->xp_rtaddr.maxlen = sizeof (struct sockaddr_storage);
233 	xprt->xp_rtaddr.len = raddr->sa_len;
234 	memcpy(xprt->xp_rtaddr.buf, raddr, raddr->sa_len);
235 
236 	error = so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa);
237 	if (error)
238 		goto cleanup_svc_vc_create;
239 
240 	xprt->xp_ltaddr.buf = mem_alloc(sizeof (struct sockaddr_storage));
241 	xprt->xp_ltaddr.maxlen = sizeof (struct sockaddr_storage);
242 	xprt->xp_ltaddr.len = sa->sa_len;
243 	memcpy(xprt->xp_ltaddr.buf, sa, sa->sa_len);
244 	free(sa, M_SONAME);
245 
246 	xprt_register(xprt);
247 
248 	SOCKBUF_LOCK(&so->so_rcv);
249 	so->so_upcallarg = xprt;
250 	so->so_upcall = svc_vc_soupcall;
251 	so->so_rcv.sb_flags |= SB_UPCALL;
252 	SOCKBUF_UNLOCK(&so->so_rcv);
253 
254 	/*
255 	 * Throw the transport into the active list in case it already
256 	 * has some data buffered.
257 	 */
258 	mtx_lock(&xprt->xp_lock);
259 	xprt_active(xprt);
260 	mtx_unlock(&xprt->xp_lock);
261 
262 	return (xprt);
263 cleanup_svc_vc_create:
264 	if (xprt) {
265 		if (xprt->xp_ltaddr.buf)
266 			mem_free(xprt->xp_ltaddr.buf,
267 			    sizeof(struct sockaddr_storage));
268 		if (xprt->xp_rtaddr.buf)
269 			mem_free(xprt->xp_rtaddr.buf,
270 			    sizeof(struct sockaddr_storage));
271 		mem_free(xprt, sizeof(*xprt));
272 	}
273 	if (cd)
274 		mem_free(cd, sizeof(*cd));
275 	return (NULL);
276 }
277 
278 /*
279  * This does all of the accept except the final call to soaccept. The
280  * caller will call soaccept after dropping its locks (soaccept may
281  * call malloc).
282  */
283 int
284 svc_vc_accept(struct socket *head, struct socket **sop)
285 {
286 	int error = 0;
287 	struct socket *so;
288 
289 	if ((head->so_options & SO_ACCEPTCONN) == 0) {
290 		error = EINVAL;
291 		goto done;
292 	}
293 #ifdef MAC
294 	SOCK_LOCK(head);
295 	error = mac_socket_check_accept(td->td_ucred, head);
296 	SOCK_UNLOCK(head);
297 	if (error != 0)
298 		goto done;
299 #endif
300 	ACCEPT_LOCK();
301 	if (TAILQ_EMPTY(&head->so_comp)) {
302 		ACCEPT_UNLOCK();
303 		error = EWOULDBLOCK;
304 		goto done;
305 	}
306 	so = TAILQ_FIRST(&head->so_comp);
307 	KASSERT(!(so->so_qstate & SQ_INCOMP), ("svc_vc_accept: so SQ_INCOMP"));
308 	KASSERT(so->so_qstate & SQ_COMP, ("svc_vc_accept: so not SQ_COMP"));
309 
310 	/*
311 	 * Before changing the flags on the socket, we have to bump the
312 	 * reference count.  Otherwise, if the protocol calls sofree(),
313 	 * the socket will be released due to a zero refcount.
314 	 * XXX might not need soref() since this is simpler than kern_accept.
315 	 */
316 	SOCK_LOCK(so);			/* soref() and so_state update */
317 	soref(so);			/* file descriptor reference */
318 
319 	TAILQ_REMOVE(&head->so_comp, so, so_list);
320 	head->so_qlen--;
321 	so->so_state |= (head->so_state & SS_NBIO);
322 	so->so_qstate &= ~SQ_COMP;
323 	so->so_head = NULL;
324 
325 	SOCK_UNLOCK(so);
326 	ACCEPT_UNLOCK();
327 
328 	*sop = so;
329 
330 	/* connection has been removed from the listen queue */
331 	KNOTE_UNLOCKED(&head->so_rcv.sb_sel.si_note, 0);
332 done:
333 	return (error);
334 }
335 
336 /*ARGSUSED*/
337 static bool_t
338 svc_vc_rendezvous_recv(SVCXPRT *xprt, struct rpc_msg *msg)
339 {
340 	struct socket *so = NULL;
341 	struct sockaddr *sa = NULL;
342 	int error;
343 
344 	/*
345 	 * The socket upcall calls xprt_active() which will eventually
346 	 * cause the server to call us here. We attempt to accept a
347 	 * connection from the socket and turn it into a new
348 	 * transport. If the accept fails, we have drained all pending
349 	 * connections so we call xprt_inactive().
350 	 *
351 	 * The lock protects us in the case where a new connection arrives
352 	 * on the socket after our call to accept fails with
353 	 * EWOULDBLOCK - the call to xprt_active() in the upcall will
354 	 * happen only after our call to xprt_inactive() which ensures
355 	 * that we will remain active. It might be possible to use
356 	 * SOCKBUF_LOCK for this - its not clear to me what locks are
357 	 * held during the upcall.
358 	 */
359 	mtx_lock(&xprt->xp_lock);
360 
361 	error = svc_vc_accept(xprt->xp_socket, &so);
362 
363 	if (error == EWOULDBLOCK) {
364 		xprt_inactive(xprt);
365 		mtx_unlock(&xprt->xp_lock);
366 		return (FALSE);
367 	}
368 
369 	if (error) {
370 		SOCKBUF_LOCK(&xprt->xp_socket->so_rcv);
371 		xprt->xp_socket->so_upcallarg = NULL;
372 		xprt->xp_socket->so_upcall = NULL;
373 		xprt->xp_socket->so_rcv.sb_flags &= ~SB_UPCALL;
374 		SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv);
375 		xprt_inactive(xprt);
376 		mtx_unlock(&xprt->xp_lock);
377 		return (FALSE);
378 	}
379 
380 	mtx_unlock(&xprt->xp_lock);
381 
382 	sa = 0;
383 	error = soaccept(so, &sa);
384 
385 	if (error) {
386 		/*
387 		 * XXX not sure if I need to call sofree or soclose here.
388 		 */
389 		if (sa)
390 			free(sa, M_SONAME);
391 		return (FALSE);
392 	}
393 
394 	/*
395 	 * svc_vc_create_conn will call xprt_register - we don't need
396 	 * to do anything with the new connection.
397 	 */
398 	if (!svc_vc_create_conn(xprt->xp_pool, so, sa))
399 		soclose(so);
400 
401 	free(sa, M_SONAME);
402 
403 	return (FALSE); /* there is never an rpc msg to be processed */
404 }
405 
406 /*ARGSUSED*/
407 static enum xprt_stat
408 svc_vc_rendezvous_stat(SVCXPRT *xprt)
409 {
410 
411 	return (XPRT_IDLE);
412 }
413 
414 static void
415 svc_vc_destroy_common(SVCXPRT *xprt)
416 {
417 	SOCKBUF_LOCK(&xprt->xp_socket->so_rcv);
418 	xprt->xp_socket->so_upcallarg = NULL;
419 	xprt->xp_socket->so_upcall = NULL;
420 	xprt->xp_socket->so_rcv.sb_flags &= ~SB_UPCALL;
421 	SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv);
422 
423 	xprt_unregister(xprt);
424 
425 	mtx_destroy(&xprt->xp_lock);
426 	if (xprt->xp_socket)
427 		(void)soclose(xprt->xp_socket);
428 
429 	if (xprt->xp_rtaddr.buf)
430 		(void) mem_free(xprt->xp_rtaddr.buf, xprt->xp_rtaddr.maxlen);
431 	if (xprt->xp_ltaddr.buf)
432 		(void) mem_free(xprt->xp_ltaddr.buf, xprt->xp_ltaddr.maxlen);
433 	(void) mem_free(xprt, sizeof (SVCXPRT));
434 
435 }
436 
437 static void
438 svc_vc_rendezvous_destroy(SVCXPRT *xprt)
439 {
440 
441 	svc_vc_destroy_common(xprt);
442 }
443 
444 static void
445 svc_vc_destroy(SVCXPRT *xprt)
446 {
447 	struct cf_conn *cd = (struct cf_conn *)xprt->xp_p1;
448 
449 	svc_vc_destroy_common(xprt);
450 
451 	if (cd->mreq)
452 		m_freem(cd->mreq);
453 	if (cd->mpending)
454 		m_freem(cd->mpending);
455 	mem_free(cd, sizeof(*cd));
456 }
457 
458 /*ARGSUSED*/
459 static bool_t
460 svc_vc_control(SVCXPRT *xprt, const u_int rq, void *in)
461 {
462 	return (FALSE);
463 }
464 
465 static bool_t
466 svc_vc_rendezvous_control(SVCXPRT *xprt, const u_int rq, void *in)
467 {
468 
469 	return (FALSE);
470 }
471 
472 static enum xprt_stat
473 svc_vc_stat(SVCXPRT *xprt)
474 {
475 	struct cf_conn *cd;
476 	struct mbuf *m;
477 	size_t n;
478 
479 	cd = (struct cf_conn *)(xprt->xp_p1);
480 
481 	if (cd->strm_stat == XPRT_DIED)
482 		return (XPRT_DIED);
483 
484 	/*
485 	 * Return XPRT_MOREREQS if we have buffered data and we are
486 	 * mid-record or if we have enough data for a record marker.
487 	 */
488 	if (cd->mpending) {
489 		if (cd->resid)
490 			return (XPRT_MOREREQS);
491 		n = 0;
492 		m = cd->mpending;
493 		while (m && n < sizeof(uint32_t)) {
494 			n += m->m_len;
495 			m = m->m_next;
496 		}
497 		if (n >= sizeof(uint32_t))
498 			return (XPRT_MOREREQS);
499 	}
500 
501 	return (XPRT_IDLE);
502 }
503 
504 static bool_t
505 svc_vc_recv(SVCXPRT *xprt, struct rpc_msg *msg)
506 {
507 	struct cf_conn *cd = (struct cf_conn *) xprt->xp_p1;
508 	struct uio uio;
509 	struct mbuf *m;
510 	int error, rcvflag;
511 
512 	for (;;) {
513 		/*
514 		 * If we have an mbuf chain in cd->mpending, try to parse a
515 		 * record from it, leaving the result in cd->mreq. If we don't
516 		 * have a complete record, leave the partial result in
517 		 * cd->mreq and try to read more from the socket.
518 		 */
519 		if (cd->mpending) {
520 			/*
521 			 * If cd->resid is non-zero, we have part of the
522 			 * record already, otherwise we are expecting a record
523 			 * marker.
524 			 */
525 			if (!cd->resid) {
526 				/*
527 				 * See if there is enough data buffered to
528 				 * make up a record marker. Make sure we can
529 				 * handle the case where the record marker is
530 				 * split across more than one mbuf.
531 				 */
532 				size_t n = 0;
533 				uint32_t header;
534 
535 				m = cd->mpending;
536 				while (n < sizeof(uint32_t) && m) {
537 					n += m->m_len;
538 					m = m->m_next;
539 				}
540 				if (n < sizeof(uint32_t))
541 					goto readmore;
542 				cd->mpending = m_pullup(cd->mpending, sizeof(uint32_t));
543 				memcpy(&header, mtod(cd->mpending, uint32_t *),
544 				    sizeof(header));
545 				header = ntohl(header);
546 				cd->eor = (header & 0x80000000) != 0;
547 				cd->resid = header & 0x7fffffff;
548 				m_adj(cd->mpending, sizeof(uint32_t));
549 			}
550 
551 			/*
552 			 * Start pulling off mbufs from cd->mpending
553 			 * until we either have a complete record or
554 			 * we run out of data. We use m_split to pull
555 			 * data - it will pull as much as possible and
556 			 * split the last mbuf if necessary.
557 			 */
558 			while (cd->mpending && cd->resid) {
559 				m = cd->mpending;
560 				cd->mpending = m_split(cd->mpending, cd->resid,
561 				    M_WAIT);
562 				if (cd->mreq)
563 					m_last(cd->mreq)->m_next = m;
564 				else
565 					cd->mreq = m;
566 				while (m) {
567 					cd->resid -= m->m_len;
568 					m = m->m_next;
569 				}
570 			}
571 
572 			/*
573 			 * If cd->resid is zero now, we have managed to
574 			 * receive a record fragment from the stream. Check
575 			 * for the end-of-record mark to see if we need more.
576 			 */
577 			if (cd->resid == 0) {
578 				if (!cd->eor)
579 					continue;
580 
581 				/*
582 				 * Success - we have a complete record in
583 				 * cd->mreq.
584 				 */
585 				xdrmbuf_create(&xprt->xp_xdrreq, cd->mreq, XDR_DECODE);
586 				cd->mreq = NULL;
587 				if (! xdr_callmsg(&xprt->xp_xdrreq, msg)) {
588 					XDR_DESTROY(&xprt->xp_xdrreq);
589 					return (FALSE);
590 				}
591 				xprt->xp_xid = msg->rm_xid;
592 
593 				return (TRUE);
594 			}
595 		}
596 
597 	readmore:
598 		/*
599 		 * The socket upcall calls xprt_active() which will eventually
600 		 * cause the server to call us here. We attempt to
601 		 * read as much as possible from the socket and put
602 		 * the result in cd->mpending. If the read fails,
603 		 * we have drained both cd->mpending and the socket so
604 		 * we can call xprt_inactive().
605 		 *
606 		 * The lock protects us in the case where a new packet arrives
607 		 * on the socket after our call to soreceive fails with
608 		 * EWOULDBLOCK - the call to xprt_active() in the upcall will
609 		 * happen only after our call to xprt_inactive() which ensures
610 		 * that we will remain active. It might be possible to use
611 		 * SOCKBUF_LOCK for this - its not clear to me what locks are
612 		 * held during the upcall.
613 		 */
614 		mtx_lock(&xprt->xp_lock);
615 
616 		uio.uio_resid = 1000000000;
617 		uio.uio_td = curthread;
618 		m = NULL;
619 		rcvflag = MSG_DONTWAIT;
620 		error = soreceive(xprt->xp_socket, NULL, &uio, &m, NULL,
621 		    &rcvflag);
622 
623 		if (error == EWOULDBLOCK) {
624 			xprt_inactive(xprt);
625 			mtx_unlock(&xprt->xp_lock);
626 			return (FALSE);
627 		}
628 
629 		if (error) {
630 			SOCKBUF_LOCK(&xprt->xp_socket->so_rcv);
631 			xprt->xp_socket->so_upcallarg = NULL;
632 			xprt->xp_socket->so_upcall = NULL;
633 			xprt->xp_socket->so_rcv.sb_flags &= ~SB_UPCALL;
634 			SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv);
635 			xprt_inactive(xprt);
636 			cd->strm_stat = XPRT_DIED;
637 			mtx_unlock(&xprt->xp_lock);
638 			return (FALSE);
639 		}
640 
641 		if (!m) {
642 			/*
643 			 * EOF - the other end has closed the socket.
644 			 */
645 			cd->strm_stat = XPRT_DIED;
646 			mtx_unlock(&xprt->xp_lock);
647 			return (FALSE);
648 		}
649 
650 		if (cd->mpending)
651 			m_last(cd->mpending)->m_next = m;
652 		else
653 			cd->mpending = m;
654 
655 		mtx_unlock(&xprt->xp_lock);
656 	}
657 }
658 
659 static bool_t
660 svc_vc_getargs(SVCXPRT *xprt, xdrproc_t xdr_args, void *args_ptr)
661 {
662 
663 	return (xdr_args(&xprt->xp_xdrreq, args_ptr));
664 }
665 
666 static bool_t
667 svc_vc_freeargs(SVCXPRT *xprt, xdrproc_t xdr_args, void *args_ptr)
668 {
669 	XDR xdrs;
670 
671 	/*
672 	 * Free the request mbuf here - this allows us to handle
673 	 * protocols where not all requests have replies
674 	 * (i.e. NLM). Note that xdrmbuf_destroy handles being called
675 	 * twice correctly - the mbuf will only be freed once.
676 	 */
677 	XDR_DESTROY(&xprt->xp_xdrreq);
678 
679 	xdrs.x_op = XDR_FREE;
680 	return (xdr_args(&xdrs, args_ptr));
681 }
682 
683 static bool_t
684 svc_vc_reply(SVCXPRT *xprt, struct rpc_msg *msg)
685 {
686 	struct mbuf *mrep;
687 	bool_t stat = FALSE;
688 	int error;
689 
690 	/*
691 	 * Leave space for record mark.
692 	 */
693 	MGETHDR(mrep, M_WAIT, MT_DATA);
694 	MCLGET(mrep, M_WAIT);
695 	mrep->m_len = 0;
696 	mrep->m_data += sizeof(uint32_t);
697 
698 	xdrmbuf_create(&xprt->xp_xdrrep, mrep, XDR_ENCODE);
699 	msg->rm_xid = xprt->xp_xid;
700 	if (xdr_replymsg(&xprt->xp_xdrrep, msg)) {
701 		m_fixhdr(mrep);
702 
703 		/*
704 		 * Prepend a record marker containing the reply length.
705 		 */
706 		M_PREPEND(mrep, sizeof(uint32_t), M_WAIT);
707 		*mtod(mrep, uint32_t *) =
708 			htonl(0x80000000 | (mrep->m_pkthdr.len
709 				- sizeof(uint32_t)));
710 		error = sosend(xprt->xp_socket, NULL, NULL, mrep, NULL,
711 		    0, curthread);
712 		if (!error) {
713 			stat = TRUE;
714 		}
715 	} else {
716 		m_freem(mrep);
717 	}
718 
719 	/*
720 	 * This frees the request mbuf chain as well. The reply mbuf
721 	 * chain was consumed by sosend.
722 	 */
723 	XDR_DESTROY(&xprt->xp_xdrreq);
724 	XDR_DESTROY(&xprt->xp_xdrrep);
725 	xprt->xp_p2 = NULL;
726 
727 	return (stat);
728 }
729 
730 static bool_t
731 svc_vc_null()
732 {
733 
734 	return (FALSE);
735 }
736 
737 static void
738 svc_vc_soupcall(struct socket *so, void *arg, int waitflag)
739 {
740 	SVCXPRT *xprt = (SVCXPRT *) arg;
741 
742 	mtx_lock(&xprt->xp_lock);
743 	xprt_active(xprt);
744 	mtx_unlock(&xprt->xp_lock);
745 }
746 
747 #if 0
748 /*
749  * Get the effective UID of the sending process. Used by rpcbind, keyserv
750  * and rpc.yppasswdd on AF_LOCAL.
751  */
752 int
753 __rpc_get_local_uid(SVCXPRT *transp, uid_t *uid) {
754 	int sock, ret;
755 	gid_t egid;
756 	uid_t euid;
757 	struct sockaddr *sa;
758 
759 	sock = transp->xp_fd;
760 	sa = (struct sockaddr *)transp->xp_rtaddr.buf;
761 	if (sa->sa_family == AF_LOCAL) {
762 		ret = getpeereid(sock, &euid, &egid);
763 		if (ret == 0)
764 			*uid = euid;
765 		return (ret);
766 	} else
767 		return (-1);
768 }
769 #endif
770