xref: /dragonfly/sys/kern/uipc_msg.c (revision 77b0c609)
1 /*
2  * Copyright (c) 2003, 2004 Jeffrey M. Hsu.  All rights reserved.
3  * Copyright (c) 2003, 2004 The DragonFly Project.  All rights reserved.
4  *
5  * This code is derived from software contributed to The DragonFly Project
6  * by Jeffrey M. Hsu.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of The DragonFly Project nor the names of its
17  *    contributors may be used to endorse or promote products derived
18  *    from this software without specific, prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
24  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
27  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
30  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/kernel.h>
37 #include <sys/msgport.h>
38 #include <sys/protosw.h>
39 #include <sys/socket.h>
40 #include <sys/socketvar.h>
41 #include <sys/socketops.h>
42 #include <sys/thread.h>
43 #include <sys/thread2.h>
44 #include <sys/msgport2.h>
45 #include <sys/spinlock2.h>
46 #include <sys/mbuf.h>
47 #include <vm/pmap.h>
48 #include <net/netmsg2.h>
49 
50 #include <net/netisr.h>
51 #include <net/netmsg.h>
52 
53 /*
54  * Abort a socket and free it.  Called from soabort() only.  soabort()
55  * got a ref on the socket which we must free on reply.
56  */
57 void
58 so_pru_abort(struct socket *so)
59 {
60 	struct netmsg_pru_abort msg;
61 
62 	netmsg_init(&msg.base, so, &curthread->td_msgport,
63 		    0, so->so_proto->pr_usrreqs->pru_abort);
64 	(void)lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
65 	sofree(msg.base.nm_so);
66 }
67 
68 /*
69  * Abort a socket and free it, asynchronously.  Called from
70  * soaborta() only.  soaborta() got a ref on the socket which we must
71  * free on reply.
72  */
73 void
74 so_pru_aborta(struct socket *so)
75 {
76 	struct netmsg_pru_abort *msg;
77 
78 	msg = kmalloc(sizeof(*msg), M_LWKTMSG, M_WAITOK | M_ZERO);
79 	netmsg_init(&msg->base, so, &netisr_afree_free_so_rport,
80 		    0, so->so_proto->pr_usrreqs->pru_abort);
81 	lwkt_sendmsg(so->so_port, &msg->base.lmsg);
82 }
83 
84 /*
85  * Abort a socket and free it.  Called from soabort_oncpu() only.
86  * Caller must make sure that the current CPU is inpcb's owner CPU.
87  */
88 void
89 so_pru_abort_oncpu(struct socket *so)
90 {
91 	struct netmsg_pru_abort msg;
92 	netisr_fn_t func = so->so_proto->pr_usrreqs->pru_abort;
93 
94 	netmsg_init(&msg.base, so, &netisr_adone_rport, 0, func);
95 	msg.base.lmsg.ms_flags &= ~(MSGF_REPLY | MSGF_DONE);
96 	msg.base.lmsg.ms_flags |= MSGF_SYNC;
97 	func((netmsg_t)&msg);
98 	KKASSERT(msg.base.lmsg.ms_flags & MSGF_DONE);
99 	sofree(msg.base.nm_so);
100 }
101 
102 int
103 so_pru_accept(struct socket *so, struct sockaddr **nam)
104 {
105 	struct netmsg_pru_accept msg;
106 
107 	netmsg_init(&msg.base, so, &curthread->td_msgport,
108 	    0, so->so_proto->pr_usrreqs->pru_accept);
109 	msg.nm_nam = nam;
110 
111 	return lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
112 }
113 
114 int
115 so_pru_attach(struct socket *so, int proto, struct pru_attach_info *ai)
116 {
117 	struct netmsg_pru_attach msg;
118 	int error;
119 
120 	netmsg_init(&msg.base, so, &curthread->td_msgport,
121 		    0, so->so_proto->pr_usrreqs->pru_attach);
122 	msg.nm_proto = proto;
123 	msg.nm_ai = ai;
124 	error = lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
125 	return (error);
126 }
127 
128 int
129 so_pru_attach_direct(struct socket *so, int proto, struct pru_attach_info *ai)
130 {
131 	struct netmsg_pru_attach msg;
132 	netisr_fn_t func = so->so_proto->pr_usrreqs->pru_attach;
133 
134 	netmsg_init(&msg.base, so, &netisr_adone_rport, 0, func);
135 	msg.base.lmsg.ms_flags &= ~(MSGF_REPLY | MSGF_DONE);
136 	msg.base.lmsg.ms_flags |= MSGF_SYNC;
137 	msg.nm_proto = proto;
138 	msg.nm_ai = ai;
139 	func((netmsg_t)&msg);
140 	KKASSERT(msg.base.lmsg.ms_flags & MSGF_DONE);
141 	return(msg.base.lmsg.ms_error);
142 }
143 
144 /*
145  * NOTE: If the target port changes the bind operation will deal with it.
146  */
147 int
148 so_pru_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
149 {
150 	struct netmsg_pru_bind msg;
151 	int error;
152 
153 	netmsg_init(&msg.base, so, &curthread->td_msgport,
154 		    0, so->so_proto->pr_usrreqs->pru_bind);
155 	msg.nm_nam = nam;
156 	msg.nm_td = td;		/* used only for prison_ip() */
157 	error = lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
158 	return (error);
159 }
160 
161 int
162 so_pru_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
163 {
164 	struct netmsg_pru_connect msg;
165 	int error;
166 
167 	netmsg_init(&msg.base, so, &curthread->td_msgport,
168 		    0, so->so_proto->pr_usrreqs->pru_connect);
169 	msg.nm_nam = nam;
170 	msg.nm_td = td;
171 	msg.nm_m = NULL;
172 	msg.nm_flags = 0;
173 	msg.nm_reconnect = 0;
174 	error = lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
175 	return (error);
176 }
177 
178 int
179 so_pru_connect2(struct socket *so1, struct socket *so2)
180 {
181 	struct netmsg_pru_connect2 msg;
182 	int error;
183 
184 	netmsg_init(&msg.base, so1, &curthread->td_msgport,
185 		    0, so1->so_proto->pr_usrreqs->pru_connect2);
186 	msg.nm_so1 = so1;
187 	msg.nm_so2 = so2;
188 	error = lwkt_domsg(so1->so_port, &msg.base.lmsg, 0);
189 	return (error);
190 }
191 
192 /*
193  * WARNING!  Synchronous call from user context.  Control function may do
194  *	     copyin/copyout.
195  */
196 int
197 so_pru_control_direct(struct socket *so, u_long cmd, caddr_t data,
198 		      struct ifnet *ifp)
199 {
200 	struct netmsg_pru_control msg;
201 	netisr_fn_t func = so->so_proto->pr_usrreqs->pru_control;
202 
203 	netmsg_init(&msg.base, so, &netisr_adone_rport, 0, func);
204 	msg.base.lmsg.ms_flags &= ~(MSGF_REPLY | MSGF_DONE);
205 	msg.base.lmsg.ms_flags |= MSGF_SYNC;
206 	msg.nm_cmd = cmd;
207 	msg.nm_data = data;
208 	msg.nm_ifp = ifp;
209 	msg.nm_td = curthread;
210 	func((netmsg_t)&msg);
211 	KKASSERT(msg.base.lmsg.ms_flags & MSGF_DONE);
212 	return(msg.base.lmsg.ms_error);
213 }
214 
215 int
216 so_pru_detach(struct socket *so)
217 {
218 	struct netmsg_pru_detach msg;
219 	int error;
220 
221 	netmsg_init(&msg.base, so, &curthread->td_msgport,
222 		    0, so->so_proto->pr_usrreqs->pru_detach);
223 	error = lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
224 	return (error);
225 }
226 
227 void
228 so_pru_detach_direct(struct socket *so)
229 {
230 	struct netmsg_pru_detach msg;
231 	netisr_fn_t func = so->so_proto->pr_usrreqs->pru_detach;
232 
233 	netmsg_init(&msg.base, so, &netisr_adone_rport, 0, func);
234 	msg.base.lmsg.ms_flags &= ~(MSGF_REPLY | MSGF_DONE);
235 	msg.base.lmsg.ms_flags |= MSGF_SYNC;
236 	func((netmsg_t)&msg);
237 	KKASSERT(msg.base.lmsg.ms_flags & MSGF_DONE);
238 }
239 
240 int
241 so_pru_disconnect(struct socket *so)
242 {
243 	struct netmsg_pru_disconnect msg;
244 	int error;
245 
246 	netmsg_init(&msg.base, so, &curthread->td_msgport,
247 		    0, so->so_proto->pr_usrreqs->pru_disconnect);
248 	error = lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
249 	return (error);
250 }
251 
252 void
253 so_pru_disconnect_direct(struct socket *so)
254 {
255 	struct netmsg_pru_disconnect msg;
256 	netisr_fn_t func = so->so_proto->pr_usrreqs->pru_disconnect;
257 
258 	netmsg_init(&msg.base, so, &netisr_adone_rport, 0, func);
259 	msg.base.lmsg.ms_flags &= ~(MSGF_REPLY | MSGF_DONE);
260 	msg.base.lmsg.ms_flags |= MSGF_SYNC;
261 	func((netmsg_t)&msg);
262 	KKASSERT(msg.base.lmsg.ms_flags & MSGF_DONE);
263 }
264 
265 int
266 so_pru_listen(struct socket *so, struct thread *td)
267 {
268 	struct netmsg_pru_listen msg;
269 	int error;
270 
271 	netmsg_init(&msg.base, so, &curthread->td_msgport,
272 		    0, so->so_proto->pr_usrreqs->pru_listen);
273 	msg.nm_td = td;		/* used only for prison_ip() XXX JH */
274 	error = lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
275 	return (error);
276 }
277 
278 int
279 so_pru_peeraddr(struct socket *so, struct sockaddr **nam)
280 {
281 	struct netmsg_pru_peeraddr msg;
282 	int error;
283 
284 	netmsg_init(&msg.base, so, &curthread->td_msgport,
285 		    0, so->so_proto->pr_usrreqs->pru_peeraddr);
286 	msg.nm_nam = nam;
287 	error = lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
288 	return (error);
289 }
290 
291 int
292 so_pru_rcvd(struct socket *so, int flags)
293 {
294 	struct netmsg_pru_rcvd msg;
295 	int error;
296 
297 	netmsg_init(&msg.base, so, &curthread->td_msgport,
298 		    0, so->so_proto->pr_usrreqs->pru_rcvd);
299 	msg.nm_flags = flags;
300 	msg.nm_pru_flags = 0;
301 	error = lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
302 	return (error);
303 }
304 
305 void
306 so_pru_rcvd_async(struct socket *so)
307 {
308 	lwkt_msg_t lmsg = &so->so_rcvd_msg.base.lmsg;
309 
310 	KASSERT(so->so_proto->pr_flags & PR_ASYNC_RCVD,
311 	    ("async pru_rcvd is not supported"));
312 
313 	spin_lock(&so->so_rcvd_spin);
314 	if (lmsg->ms_flags & MSGF_DONE)
315 		lwkt_sendmsg(so->so_port, lmsg);
316 	spin_unlock(&so->so_rcvd_spin);
317 }
318 
319 int
320 so_pru_rcvoob(struct socket *so, struct mbuf *m, int flags)
321 {
322 	struct netmsg_pru_rcvoob msg;
323 	int error;
324 
325 	netmsg_init(&msg.base, so, &curthread->td_msgport,
326 		    0, so->so_proto->pr_usrreqs->pru_rcvoob);
327 	msg.nm_m = m;
328 	msg.nm_flags = flags;
329 	error = lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
330 	return (error);
331 }
332 
333 /*
334  * NOTE: If the target port changes the implied connect will deal with it.
335  */
336 int
337 so_pru_send(struct socket *so, int flags, struct mbuf *m,
338 	    struct sockaddr *addr, struct mbuf *control, struct thread *td)
339 {
340 	struct netmsg_pru_send msg;
341 	int error;
342 
343 	netmsg_init(&msg.base, so, &curthread->td_msgport,
344 		    0, so->so_proto->pr_usrreqs->pru_send);
345 	msg.nm_flags = flags;
346 	msg.nm_m = m;
347 	msg.nm_addr = addr;
348 	msg.nm_control = control;
349 	msg.nm_td = td;
350 	error = lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
351 	return (error);
352 }
353 
354 void
355 so_pru_sync(struct socket *so)
356 {
357 	struct netmsg_base msg;
358 
359 	netmsg_init(&msg, so, &curthread->td_msgport, 0,
360 	    netmsg_sync_handler);
361 	lwkt_domsg(so->so_port, &msg.lmsg, 0);
362 }
363 
364 void
365 so_pru_send_async(struct socket *so, int flags, struct mbuf *m,
366 	    struct sockaddr *addr0, struct mbuf *control, struct thread *td)
367 {
368 	struct netmsg_pru_send *msg;
369 	struct sockaddr *addr = NULL;
370 
371 	KASSERT(so->so_proto->pr_flags & PR_ASYNC_SEND,
372 	    ("async pru_send is not supported"));
373 
374 	flags |= PRUS_NOREPLY;
375 	if (addr0 != NULL) {
376 		addr = kmalloc(addr0->sa_len, M_SONAME, M_WAITOK);
377 		memcpy(addr, addr0, addr0->sa_len);
378 		flags |= PRUS_FREEADDR;
379 	}
380 
381 	msg = &m->m_hdr.mh_sndmsg;
382 	netmsg_init(&msg->base, so, &netisr_apanic_rport,
383 		    0, so->so_proto->pr_usrreqs->pru_send);
384 	msg->nm_flags = flags;
385 	msg->nm_m = m;
386 	msg->nm_addr = addr;
387 	msg->nm_control = control;
388 	msg->nm_td = td;
389 	lwkt_sendmsg(so->so_port, &msg->base.lmsg);
390 }
391 
392 int
393 so_pru_sense(struct socket *so, struct stat *sb)
394 {
395 	struct netmsg_pru_sense msg;
396 	int error;
397 
398 	netmsg_init(&msg.base, so, &curthread->td_msgport,
399 		    0, so->so_proto->pr_usrreqs->pru_sense);
400 	msg.nm_stat = sb;
401 	error = lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
402 	return (error);
403 }
404 
405 int
406 so_pru_shutdown(struct socket *so)
407 {
408 	struct netmsg_pru_shutdown msg;
409 	int error;
410 
411 	netmsg_init(&msg.base, so, &curthread->td_msgport,
412 		    0, so->so_proto->pr_usrreqs->pru_shutdown);
413 	error = lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
414 	return (error);
415 }
416 
417 int
418 so_pru_sockaddr(struct socket *so, struct sockaddr **nam)
419 {
420 	struct netmsg_pru_sockaddr msg;
421 	int error;
422 
423 	netmsg_init(&msg.base, so, &curthread->td_msgport,
424 		    0, so->so_proto->pr_usrreqs->pru_sockaddr);
425 	msg.nm_nam = nam;
426 	error = lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
427 	return (error);
428 }
429 
430 int
431 so_pr_ctloutput(struct socket *so, struct sockopt *sopt)
432 {
433 	struct netmsg_pr_ctloutput msg;
434 	int error;
435 
436 	KKASSERT(!sopt->sopt_val || kva_p(sopt->sopt_val));
437 	netmsg_init(&msg.base, so, &curthread->td_msgport,
438 		    0, so->so_proto->pr_ctloutput);
439 	msg.nm_sopt = sopt;
440 	error = lwkt_domsg(so->so_port, &msg.base.lmsg, 0);
441 	return (error);
442 }
443 
444 /*
445  * Protocol control input, typically via icmp.
446  *
447  * If the protocol pr_ctlport is not NULL we call it to figure out the
448  * protocol port.  If NULL is returned we can just return, otherwise
449  * we issue a netmsg to call pr_ctlinput in the proper thread.
450  *
451  * This must be done synchronously as arg and/or extra may point to
452  * temporary data.
453  */
454 void
455 so_pru_ctlinput(struct protosw *pr, int cmd, struct sockaddr *arg, void *extra)
456 {
457 	struct netmsg_pru_ctlinput msg;
458 	lwkt_port_t port;
459 
460 	if (pr->pr_ctlport == NULL)
461 		return;
462 	KKASSERT(pr->pr_ctlinput != NULL);
463 	port = pr->pr_ctlport(cmd, arg, extra);
464 	if (port == NULL)
465 		return;
466 	netmsg_init(&msg.base, NULL, &curthread->td_msgport,
467 		    0, pr->pr_ctlinput);
468 	msg.nm_cmd = cmd;
469 	msg.nm_arg = arg;
470 	msg.nm_extra = extra;
471 	lwkt_domsg(port, &msg.base.lmsg, 0);
472 }
473 
474 /*
475  * If we convert all the protosw pr_ functions for all the protocols
476  * to take a message directly, this layer can go away.  For the moment
477  * our dispatcher ignores the return value, but since we are handling
478  * the replymsg ourselves we return EASYNC by convention.
479  */
480 
481 /*
482  * Handle a predicate event request.  This function is only called once
483  * when the predicate message queueing request is received.
484  */
485 void
486 netmsg_so_notify(netmsg_t msg)
487 {
488 	struct lwkt_token *tok;
489 	struct signalsockbuf *ssb;
490 
491 	ssb = (msg->notify.nm_etype & NM_REVENT) ?
492 			&msg->base.nm_so->so_rcv :
493 			&msg->base.nm_so->so_snd;
494 
495 	/*
496 	 * Reply immediately if the event has occured, otherwise queue the
497 	 * request.
498 	 *
499 	 * NOTE: Socket can change if this is an accept predicate so cache
500 	 *	 the token.
501 	 */
502 	tok = lwkt_token_pool_lookup(msg->base.nm_so);
503 	lwkt_gettoken(tok);
504 	if (msg->notify.nm_predicate(&msg->notify)) {
505 		lwkt_reltoken(tok);
506 		lwkt_replymsg(&msg->base.lmsg,
507 			      msg->base.lmsg.ms_error);
508 	} else {
509 		TAILQ_INSERT_TAIL(&ssb->ssb_kq.ki_mlist, &msg->notify, nm_list);
510 		atomic_set_int(&ssb->ssb_flags, SSB_MEVENT);
511 		lwkt_reltoken(tok);
512 	}
513 }
514 
515 /*
516  * Called by doio when trying to abort a netmsg_so_notify message.
517  * Unlike the other functions this one is dispatched directly by
518  * the LWKT subsystem, so it takes a lwkt_msg_t as an argument.
519  *
520  * The original message, lmsg, is under the control of the caller and
521  * will not be destroyed until we return so we can safely reference it
522  * in our synchronous abort request.
523  *
524  * This part of the abort request occurs on the originating cpu which
525  * means we may race the message flags and the original message may
526  * not even have been processed by the target cpu yet.
527  */
528 void
529 netmsg_so_notify_doabort(lwkt_msg_t lmsg)
530 {
531 	struct netmsg_so_notify_abort msg;
532 
533 	if ((lmsg->ms_flags & (MSGF_DONE | MSGF_REPLY)) == 0) {
534 		netmsg_init(&msg.base, NULL, &curthread->td_msgport,
535 			    0, netmsg_so_notify_abort);
536 		msg.nm_notifymsg = (void *)lmsg;
537 		lwkt_domsg(lmsg->ms_target_port, &msg.base.lmsg, 0);
538 	}
539 }
540 
541 /*
542  * Predicate requests can be aborted.  This function is only called once
543  * and will interlock against processing/reply races (since such races
544  * occur on the same thread that controls the port where the abort is
545  * requeued).
546  *
547  * This part of the abort request occurs on the target cpu.  The message
548  * flags must be tested again in case the test that we did on the
549  * originating cpu raced.  Since messages are handled in sequence, the
550  * original message will have already been handled by the loop and either
551  * replied to or queued.
552  *
553  * We really only need to interlock with MSGF_REPLY (a bit that is set on
554  * our cpu when we reply).  Note that MSGF_DONE is not set until the
555  * reply reaches the originating cpu.  Test both bits anyway.
556  */
557 void
558 netmsg_so_notify_abort(netmsg_t msg)
559 {
560 	struct netmsg_so_notify_abort *abrtmsg = &msg->notify_abort;
561 	struct netmsg_so_notify *nmsg = abrtmsg->nm_notifymsg;
562 	struct signalsockbuf *ssb;
563 
564 	/*
565 	 * The original notify message is not destroyed until after the
566 	 * abort request is returned, so we can check its state.
567 	 */
568 	lwkt_getpooltoken(nmsg->base.nm_so);
569 	if ((nmsg->base.lmsg.ms_flags & (MSGF_DONE | MSGF_REPLY)) == 0) {
570 		ssb = (nmsg->nm_etype & NM_REVENT) ?
571 				&nmsg->base.nm_so->so_rcv :
572 				&nmsg->base.nm_so->so_snd;
573 		TAILQ_REMOVE(&ssb->ssb_kq.ki_mlist, nmsg, nm_list);
574 		lwkt_relpooltoken(nmsg->base.nm_so);
575 		lwkt_replymsg(&nmsg->base.lmsg, EINTR);
576 	} else {
577 		lwkt_relpooltoken(nmsg->base.nm_so);
578 	}
579 
580 	/*
581 	 * Reply to the abort message
582 	 */
583 	lwkt_replymsg(&abrtmsg->base.lmsg, 0);
584 }
585 
586 void
587 so_async_rcvd_reply(struct socket *so)
588 {
589 	spin_lock(&so->so_rcvd_spin);
590 	lwkt_replymsg(&so->so_rcvd_msg.base.lmsg, 0);
591 	spin_unlock(&so->so_rcvd_spin);
592 }
593 
594 void
595 so_async_rcvd_drop(struct socket *so)
596 {
597 	lwkt_msg_t lmsg = &so->so_rcvd_msg.base.lmsg;
598 
599 	spin_lock(&so->so_rcvd_spin);
600 	if ((lmsg->ms_flags & MSGF_DONE) == 0)
601 		lwkt_dropmsg(lmsg);
602 	spin_unlock(&so->so_rcvd_spin);
603 }
604