xref: /openbmc/linux/fs/afs/rxrpc.c (revision c21b37f6)
1 /* Maintain an RxRPC server socket to do AFS communications through
2  *
3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 
12 #include <net/sock.h>
13 #include <net/af_rxrpc.h>
14 #include <rxrpc/packet.h>
15 #include "internal.h"
16 #include "afs_cm.h"
17 
18 static struct socket *afs_socket; /* my RxRPC socket */
19 static struct workqueue_struct *afs_async_calls;
20 static atomic_t afs_outstanding_calls;
21 static atomic_t afs_outstanding_skbs;
22 
23 static void afs_wake_up_call_waiter(struct afs_call *);
24 static int afs_wait_for_call_to_complete(struct afs_call *);
25 static void afs_wake_up_async_call(struct afs_call *);
26 static int afs_dont_wait_for_call_to_complete(struct afs_call *);
27 static void afs_process_async_call(struct work_struct *);
28 static void afs_rx_interceptor(struct sock *, unsigned long, struct sk_buff *);
29 static int afs_deliver_cm_op_id(struct afs_call *, struct sk_buff *, bool);
30 
31 /* synchronous call management */
32 const struct afs_wait_mode afs_sync_call = {
33 	.rx_wakeup	= afs_wake_up_call_waiter,
34 	.wait		= afs_wait_for_call_to_complete,
35 };
36 
37 /* asynchronous call management */
38 const struct afs_wait_mode afs_async_call = {
39 	.rx_wakeup	= afs_wake_up_async_call,
40 	.wait		= afs_dont_wait_for_call_to_complete,
41 };
42 
43 /* asynchronous incoming call management */
44 static const struct afs_wait_mode afs_async_incoming_call = {
45 	.rx_wakeup	= afs_wake_up_async_call,
46 };
47 
48 /* asynchronous incoming call initial processing */
49 static const struct afs_call_type afs_RXCMxxxx = {
50 	.name		= "CB.xxxx",
51 	.deliver	= afs_deliver_cm_op_id,
52 	.abort_to_error	= afs_abort_to_error,
53 };
54 
55 static void afs_collect_incoming_call(struct work_struct *);
56 
57 static struct sk_buff_head afs_incoming_calls;
58 static DECLARE_WORK(afs_collect_incoming_call_work, afs_collect_incoming_call);
59 
60 /*
61  * open an RxRPC socket and bind it to be a server for callback notifications
62  * - the socket is left in blocking mode and non-blocking ops use MSG_DONTWAIT
63  */
64 int afs_open_socket(void)
65 {
66 	struct sockaddr_rxrpc srx;
67 	struct socket *socket;
68 	int ret;
69 
70 	_enter("");
71 
72 	skb_queue_head_init(&afs_incoming_calls);
73 
74 	afs_async_calls = create_singlethread_workqueue("kafsd");
75 	if (!afs_async_calls) {
76 		_leave(" = -ENOMEM [wq]");
77 		return -ENOMEM;
78 	}
79 
80 	ret = sock_create_kern(AF_RXRPC, SOCK_DGRAM, PF_INET, &socket);
81 	if (ret < 0) {
82 		destroy_workqueue(afs_async_calls);
83 		_leave(" = %d [socket]", ret);
84 		return ret;
85 	}
86 
87 	socket->sk->sk_allocation = GFP_NOFS;
88 
89 	/* bind the callback manager's address to make this a server socket */
90 	srx.srx_family			= AF_RXRPC;
91 	srx.srx_service			= CM_SERVICE;
92 	srx.transport_type		= SOCK_DGRAM;
93 	srx.transport_len		= sizeof(srx.transport.sin);
94 	srx.transport.sin.sin_family	= AF_INET;
95 	srx.transport.sin.sin_port	= htons(AFS_CM_PORT);
96 	memset(&srx.transport.sin.sin_addr, 0,
97 	       sizeof(srx.transport.sin.sin_addr));
98 
99 	ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
100 	if (ret < 0) {
101 		sock_release(socket);
102 		_leave(" = %d [bind]", ret);
103 		return ret;
104 	}
105 
106 	rxrpc_kernel_intercept_rx_messages(socket, afs_rx_interceptor);
107 
108 	afs_socket = socket;
109 	_leave(" = 0");
110 	return 0;
111 }
112 
113 /*
114  * close the RxRPC socket AFS was using
115  */
116 void afs_close_socket(void)
117 {
118 	_enter("");
119 
120 	sock_release(afs_socket);
121 
122 	_debug("dework");
123 	destroy_workqueue(afs_async_calls);
124 
125 	ASSERTCMP(atomic_read(&afs_outstanding_skbs), ==, 0);
126 	ASSERTCMP(atomic_read(&afs_outstanding_calls), ==, 0);
127 	_leave("");
128 }
129 
130 /*
131  * note that the data in a socket buffer is now delivered and that the buffer
132  * should be freed
133  */
134 static void afs_data_delivered(struct sk_buff *skb)
135 {
136 	if (!skb) {
137 		_debug("DLVR NULL [%d]", atomic_read(&afs_outstanding_skbs));
138 		dump_stack();
139 	} else {
140 		_debug("DLVR %p{%u} [%d]",
141 		       skb, skb->mark, atomic_read(&afs_outstanding_skbs));
142 		if (atomic_dec_return(&afs_outstanding_skbs) == -1)
143 			BUG();
144 		rxrpc_kernel_data_delivered(skb);
145 	}
146 }
147 
148 /*
149  * free a socket buffer
150  */
151 static void afs_free_skb(struct sk_buff *skb)
152 {
153 	if (!skb) {
154 		_debug("FREE NULL [%d]", atomic_read(&afs_outstanding_skbs));
155 		dump_stack();
156 	} else {
157 		_debug("FREE %p{%u} [%d]",
158 		       skb, skb->mark, atomic_read(&afs_outstanding_skbs));
159 		if (atomic_dec_return(&afs_outstanding_skbs) == -1)
160 			BUG();
161 		rxrpc_kernel_free_skb(skb);
162 	}
163 }
164 
165 /*
166  * free a call
167  */
168 static void afs_free_call(struct afs_call *call)
169 {
170 	_debug("DONE %p{%s} [%d]",
171 	       call, call->type->name, atomic_read(&afs_outstanding_calls));
172 	if (atomic_dec_return(&afs_outstanding_calls) == -1)
173 		BUG();
174 
175 	ASSERTCMP(call->rxcall, ==, NULL);
176 	ASSERT(!work_pending(&call->async_work));
177 	ASSERT(skb_queue_empty(&call->rx_queue));
178 	ASSERT(call->type->name != NULL);
179 
180 	kfree(call->request);
181 	kfree(call);
182 }
183 
184 /*
185  * allocate a call with flat request and reply buffers
186  */
187 struct afs_call *afs_alloc_flat_call(const struct afs_call_type *type,
188 				     size_t request_size, size_t reply_size)
189 {
190 	struct afs_call *call;
191 
192 	call = kzalloc(sizeof(*call), GFP_NOFS);
193 	if (!call)
194 		goto nomem_call;
195 
196 	_debug("CALL %p{%s} [%d]",
197 	       call, type->name, atomic_read(&afs_outstanding_calls));
198 	atomic_inc(&afs_outstanding_calls);
199 
200 	call->type = type;
201 	call->request_size = request_size;
202 	call->reply_max = reply_size;
203 
204 	if (request_size) {
205 		call->request = kmalloc(request_size, GFP_NOFS);
206 		if (!call->request)
207 			goto nomem_free;
208 	}
209 
210 	if (reply_size) {
211 		call->buffer = kmalloc(reply_size, GFP_NOFS);
212 		if (!call->buffer)
213 			goto nomem_free;
214 	}
215 
216 	init_waitqueue_head(&call->waitq);
217 	skb_queue_head_init(&call->rx_queue);
218 	return call;
219 
220 nomem_free:
221 	afs_free_call(call);
222 nomem_call:
223 	return NULL;
224 }
225 
226 /*
227  * clean up a call with flat buffer
228  */
229 void afs_flat_call_destructor(struct afs_call *call)
230 {
231 	_enter("");
232 
233 	kfree(call->request);
234 	call->request = NULL;
235 	kfree(call->buffer);
236 	call->buffer = NULL;
237 }
238 
239 /*
240  * attach the data from a bunch of pages on an inode to a call
241  */
242 int afs_send_pages(struct afs_call *call, struct msghdr *msg, struct kvec *iov)
243 {
244 	struct page *pages[8];
245 	unsigned count, n, loop, offset, to;
246 	pgoff_t first = call->first, last = call->last;
247 	int ret;
248 
249 	_enter("");
250 
251 	offset = call->first_offset;
252 	call->first_offset = 0;
253 
254 	do {
255 		_debug("attach %lx-%lx", first, last);
256 
257 		count = last - first + 1;
258 		if (count > ARRAY_SIZE(pages))
259 			count = ARRAY_SIZE(pages);
260 		n = find_get_pages_contig(call->mapping, first, count, pages);
261 		ASSERTCMP(n, ==, count);
262 
263 		loop = 0;
264 		do {
265 			msg->msg_flags = 0;
266 			to = PAGE_SIZE;
267 			if (first + loop >= last)
268 				to = call->last_to;
269 			else
270 				msg->msg_flags = MSG_MORE;
271 			iov->iov_base = kmap(pages[loop]) + offset;
272 			iov->iov_len = to - offset;
273 			offset = 0;
274 
275 			_debug("- range %u-%u%s",
276 			       offset, to, msg->msg_flags ? " [more]" : "");
277 			msg->msg_iov = (struct iovec *) iov;
278 			msg->msg_iovlen = 1;
279 
280 			/* have to change the state *before* sending the last
281 			 * packet as RxRPC might give us the reply before it
282 			 * returns from sending the request */
283 			if (first + loop >= last)
284 				call->state = AFS_CALL_AWAIT_REPLY;
285 			ret = rxrpc_kernel_send_data(call->rxcall, msg,
286 						     to - offset);
287 			kunmap(pages[loop]);
288 			if (ret < 0)
289 				break;
290 		} while (++loop < count);
291 		first += count;
292 
293 		for (loop = 0; loop < count; loop++)
294 			put_page(pages[loop]);
295 		if (ret < 0)
296 			break;
297 	} while (first <= last);
298 
299 	_leave(" = %d", ret);
300 	return ret;
301 }
302 
303 /*
304  * initiate a call
305  */
306 int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
307 		  const struct afs_wait_mode *wait_mode)
308 {
309 	struct sockaddr_rxrpc srx;
310 	struct rxrpc_call *rxcall;
311 	struct msghdr msg;
312 	struct kvec iov[1];
313 	int ret;
314 
315 	_enter("%x,{%d},", addr->s_addr, ntohs(call->port));
316 
317 	ASSERT(call->type != NULL);
318 	ASSERT(call->type->name != NULL);
319 
320 	_debug("____MAKE %p{%s,%x} [%d]____",
321 	       call, call->type->name, key_serial(call->key),
322 	       atomic_read(&afs_outstanding_calls));
323 
324 	call->wait_mode = wait_mode;
325 	INIT_WORK(&call->async_work, afs_process_async_call);
326 
327 	memset(&srx, 0, sizeof(srx));
328 	srx.srx_family = AF_RXRPC;
329 	srx.srx_service = call->service_id;
330 	srx.transport_type = SOCK_DGRAM;
331 	srx.transport_len = sizeof(srx.transport.sin);
332 	srx.transport.sin.sin_family = AF_INET;
333 	srx.transport.sin.sin_port = call->port;
334 	memcpy(&srx.transport.sin.sin_addr, addr, 4);
335 
336 	/* create a call */
337 	rxcall = rxrpc_kernel_begin_call(afs_socket, &srx, call->key,
338 					 (unsigned long) call, gfp);
339 	call->key = NULL;
340 	if (IS_ERR(rxcall)) {
341 		ret = PTR_ERR(rxcall);
342 		goto error_kill_call;
343 	}
344 
345 	call->rxcall = rxcall;
346 
347 	/* send the request */
348 	iov[0].iov_base	= call->request;
349 	iov[0].iov_len	= call->request_size;
350 
351 	msg.msg_name		= NULL;
352 	msg.msg_namelen		= 0;
353 	msg.msg_iov		= (struct iovec *) iov;
354 	msg.msg_iovlen		= 1;
355 	msg.msg_control		= NULL;
356 	msg.msg_controllen	= 0;
357 	msg.msg_flags		= (call->send_pages ? MSG_MORE : 0);
358 
359 	/* have to change the state *before* sending the last packet as RxRPC
360 	 * might give us the reply before it returns from sending the
361 	 * request */
362 	if (!call->send_pages)
363 		call->state = AFS_CALL_AWAIT_REPLY;
364 	ret = rxrpc_kernel_send_data(rxcall, &msg, call->request_size);
365 	if (ret < 0)
366 		goto error_do_abort;
367 
368 	if (call->send_pages) {
369 		ret = afs_send_pages(call, &msg, iov);
370 		if (ret < 0)
371 			goto error_do_abort;
372 	}
373 
374 	/* at this point, an async call may no longer exist as it may have
375 	 * already completed */
376 	return wait_mode->wait(call);
377 
378 error_do_abort:
379 	rxrpc_kernel_abort_call(rxcall, RX_USER_ABORT);
380 	rxrpc_kernel_end_call(rxcall);
381 	call->rxcall = NULL;
382 error_kill_call:
383 	call->type->destructor(call);
384 	afs_free_call(call);
385 	_leave(" = %d", ret);
386 	return ret;
387 }
388 
389 /*
390  * handles intercepted messages that were arriving in the socket's Rx queue
391  * - called with the socket receive queue lock held to ensure message ordering
392  * - called with softirqs disabled
393  */
394 static void afs_rx_interceptor(struct sock *sk, unsigned long user_call_ID,
395 			       struct sk_buff *skb)
396 {
397 	struct afs_call *call = (struct afs_call *) user_call_ID;
398 
399 	_enter("%p,,%u", call, skb->mark);
400 
401 	_debug("ICPT %p{%u} [%d]",
402 	       skb, skb->mark, atomic_read(&afs_outstanding_skbs));
403 
404 	ASSERTCMP(sk, ==, afs_socket->sk);
405 	atomic_inc(&afs_outstanding_skbs);
406 
407 	if (!call) {
408 		/* its an incoming call for our callback service */
409 		skb_queue_tail(&afs_incoming_calls, skb);
410 		schedule_work(&afs_collect_incoming_call_work);
411 	} else {
412 		/* route the messages directly to the appropriate call */
413 		skb_queue_tail(&call->rx_queue, skb);
414 		call->wait_mode->rx_wakeup(call);
415 	}
416 
417 	_leave("");
418 }
419 
420 /*
421  * deliver messages to a call
422  */
423 static void afs_deliver_to_call(struct afs_call *call)
424 {
425 	struct sk_buff *skb;
426 	bool last;
427 	u32 abort_code;
428 	int ret;
429 
430 	_enter("");
431 
432 	while ((call->state == AFS_CALL_AWAIT_REPLY ||
433 		call->state == AFS_CALL_AWAIT_OP_ID ||
434 		call->state == AFS_CALL_AWAIT_REQUEST ||
435 		call->state == AFS_CALL_AWAIT_ACK) &&
436 	       (skb = skb_dequeue(&call->rx_queue))) {
437 		switch (skb->mark) {
438 		case RXRPC_SKB_MARK_DATA:
439 			_debug("Rcv DATA");
440 			last = rxrpc_kernel_is_data_last(skb);
441 			ret = call->type->deliver(call, skb, last);
442 			switch (ret) {
443 			case 0:
444 				if (last &&
445 				    call->state == AFS_CALL_AWAIT_REPLY)
446 					call->state = AFS_CALL_COMPLETE;
447 				break;
448 			case -ENOTCONN:
449 				abort_code = RX_CALL_DEAD;
450 				goto do_abort;
451 			case -ENOTSUPP:
452 				abort_code = RX_INVALID_OPERATION;
453 				goto do_abort;
454 			default:
455 				abort_code = RXGEN_CC_UNMARSHAL;
456 				if (call->state != AFS_CALL_AWAIT_REPLY)
457 					abort_code = RXGEN_SS_UNMARSHAL;
458 			do_abort:
459 				rxrpc_kernel_abort_call(call->rxcall,
460 							abort_code);
461 				call->error = ret;
462 				call->state = AFS_CALL_ERROR;
463 				break;
464 			}
465 			afs_data_delivered(skb);
466 			skb = NULL;
467 			continue;
468 		case RXRPC_SKB_MARK_FINAL_ACK:
469 			_debug("Rcv ACK");
470 			call->state = AFS_CALL_COMPLETE;
471 			break;
472 		case RXRPC_SKB_MARK_BUSY:
473 			_debug("Rcv BUSY");
474 			call->error = -EBUSY;
475 			call->state = AFS_CALL_BUSY;
476 			break;
477 		case RXRPC_SKB_MARK_REMOTE_ABORT:
478 			abort_code = rxrpc_kernel_get_abort_code(skb);
479 			call->error = call->type->abort_to_error(abort_code);
480 			call->state = AFS_CALL_ABORTED;
481 			_debug("Rcv ABORT %u -> %d", abort_code, call->error);
482 			break;
483 		case RXRPC_SKB_MARK_NET_ERROR:
484 			call->error = -rxrpc_kernel_get_error_number(skb);
485 			call->state = AFS_CALL_ERROR;
486 			_debug("Rcv NET ERROR %d", call->error);
487 			break;
488 		case RXRPC_SKB_MARK_LOCAL_ERROR:
489 			call->error = -rxrpc_kernel_get_error_number(skb);
490 			call->state = AFS_CALL_ERROR;
491 			_debug("Rcv LOCAL ERROR %d", call->error);
492 			break;
493 		default:
494 			BUG();
495 			break;
496 		}
497 
498 		afs_free_skb(skb);
499 	}
500 
501 	/* make sure the queue is empty if the call is done with (we might have
502 	 * aborted the call early because of an unmarshalling error) */
503 	if (call->state >= AFS_CALL_COMPLETE) {
504 		while ((skb = skb_dequeue(&call->rx_queue)))
505 			afs_free_skb(skb);
506 		if (call->incoming) {
507 			rxrpc_kernel_end_call(call->rxcall);
508 			call->rxcall = NULL;
509 			call->type->destructor(call);
510 			afs_free_call(call);
511 		}
512 	}
513 
514 	_leave("");
515 }
516 
517 /*
518  * wait synchronously for a call to complete
519  */
520 static int afs_wait_for_call_to_complete(struct afs_call *call)
521 {
522 	struct sk_buff *skb;
523 	int ret;
524 
525 	DECLARE_WAITQUEUE(myself, current);
526 
527 	_enter("");
528 
529 	add_wait_queue(&call->waitq, &myself);
530 	for (;;) {
531 		set_current_state(TASK_INTERRUPTIBLE);
532 
533 		/* deliver any messages that are in the queue */
534 		if (!skb_queue_empty(&call->rx_queue)) {
535 			__set_current_state(TASK_RUNNING);
536 			afs_deliver_to_call(call);
537 			continue;
538 		}
539 
540 		ret = call->error;
541 		if (call->state >= AFS_CALL_COMPLETE)
542 			break;
543 		ret = -EINTR;
544 		if (signal_pending(current))
545 			break;
546 		schedule();
547 	}
548 
549 	remove_wait_queue(&call->waitq, &myself);
550 	__set_current_state(TASK_RUNNING);
551 
552 	/* kill the call */
553 	if (call->state < AFS_CALL_COMPLETE) {
554 		_debug("call incomplete");
555 		rxrpc_kernel_abort_call(call->rxcall, RX_CALL_DEAD);
556 		while ((skb = skb_dequeue(&call->rx_queue)))
557 			afs_free_skb(skb);
558 	}
559 
560 	_debug("call complete");
561 	rxrpc_kernel_end_call(call->rxcall);
562 	call->rxcall = NULL;
563 	call->type->destructor(call);
564 	afs_free_call(call);
565 	_leave(" = %d", ret);
566 	return ret;
567 }
568 
569 /*
570  * wake up a waiting call
571  */
572 static void afs_wake_up_call_waiter(struct afs_call *call)
573 {
574 	wake_up(&call->waitq);
575 }
576 
577 /*
578  * wake up an asynchronous call
579  */
580 static void afs_wake_up_async_call(struct afs_call *call)
581 {
582 	_enter("");
583 	queue_work(afs_async_calls, &call->async_work);
584 }
585 
586 /*
587  * put a call into asynchronous mode
588  * - mustn't touch the call descriptor as the call my have completed by the
589  *   time we get here
590  */
591 static int afs_dont_wait_for_call_to_complete(struct afs_call *call)
592 {
593 	_enter("");
594 	return -EINPROGRESS;
595 }
596 
597 /*
598  * delete an asynchronous call
599  */
600 static void afs_delete_async_call(struct work_struct *work)
601 {
602 	struct afs_call *call =
603 		container_of(work, struct afs_call, async_work);
604 
605 	_enter("");
606 
607 	afs_free_call(call);
608 
609 	_leave("");
610 }
611 
612 /*
613  * perform processing on an asynchronous call
614  * - on a multiple-thread workqueue this work item may try to run on several
615  *   CPUs at the same time
616  */
617 static void afs_process_async_call(struct work_struct *work)
618 {
619 	struct afs_call *call =
620 		container_of(work, struct afs_call, async_work);
621 
622 	_enter("");
623 
624 	if (!skb_queue_empty(&call->rx_queue))
625 		afs_deliver_to_call(call);
626 
627 	if (call->state >= AFS_CALL_COMPLETE && call->wait_mode) {
628 		if (call->wait_mode->async_complete)
629 			call->wait_mode->async_complete(call->reply,
630 							call->error);
631 		call->reply = NULL;
632 
633 		/* kill the call */
634 		rxrpc_kernel_end_call(call->rxcall);
635 		call->rxcall = NULL;
636 		if (call->type->destructor)
637 			call->type->destructor(call);
638 
639 		/* we can't just delete the call because the work item may be
640 		 * queued */
641 		PREPARE_WORK(&call->async_work, afs_delete_async_call);
642 		queue_work(afs_async_calls, &call->async_work);
643 	}
644 
645 	_leave("");
646 }
647 
648 /*
649  * empty a socket buffer into a flat reply buffer
650  */
651 void afs_transfer_reply(struct afs_call *call, struct sk_buff *skb)
652 {
653 	size_t len = skb->len;
654 
655 	if (skb_copy_bits(skb, 0, call->buffer + call->reply_size, len) < 0)
656 		BUG();
657 	call->reply_size += len;
658 }
659 
660 /*
661  * accept the backlog of incoming calls
662  */
663 static void afs_collect_incoming_call(struct work_struct *work)
664 {
665 	struct rxrpc_call *rxcall;
666 	struct afs_call *call = NULL;
667 	struct sk_buff *skb;
668 
669 	while ((skb = skb_dequeue(&afs_incoming_calls))) {
670 		_debug("new call");
671 
672 		/* don't need the notification */
673 		afs_free_skb(skb);
674 
675 		if (!call) {
676 			call = kzalloc(sizeof(struct afs_call), GFP_KERNEL);
677 			if (!call) {
678 				rxrpc_kernel_reject_call(afs_socket);
679 				return;
680 			}
681 
682 			INIT_WORK(&call->async_work, afs_process_async_call);
683 			call->wait_mode = &afs_async_incoming_call;
684 			call->type = &afs_RXCMxxxx;
685 			init_waitqueue_head(&call->waitq);
686 			skb_queue_head_init(&call->rx_queue);
687 			call->state = AFS_CALL_AWAIT_OP_ID;
688 
689 			_debug("CALL %p{%s} [%d]",
690 			       call, call->type->name,
691 			       atomic_read(&afs_outstanding_calls));
692 			atomic_inc(&afs_outstanding_calls);
693 		}
694 
695 		rxcall = rxrpc_kernel_accept_call(afs_socket,
696 						  (unsigned long) call);
697 		if (!IS_ERR(rxcall)) {
698 			call->rxcall = rxcall;
699 			call = NULL;
700 		}
701 	}
702 
703 	if (call)
704 		afs_free_call(call);
705 }
706 
707 /*
708  * grab the operation ID from an incoming cache manager call
709  */
710 static int afs_deliver_cm_op_id(struct afs_call *call, struct sk_buff *skb,
711 				bool last)
712 {
713 	size_t len = skb->len;
714 	void *oibuf = (void *) &call->operation_ID;
715 
716 	_enter("{%u},{%zu},%d", call->offset, len, last);
717 
718 	ASSERTCMP(call->offset, <, 4);
719 
720 	/* the operation ID forms the first four bytes of the request data */
721 	len = min_t(size_t, len, 4 - call->offset);
722 	if (skb_copy_bits(skb, 0, oibuf + call->offset, len) < 0)
723 		BUG();
724 	if (!pskb_pull(skb, len))
725 		BUG();
726 	call->offset += len;
727 
728 	if (call->offset < 4) {
729 		if (last) {
730 			_leave(" = -EBADMSG [op ID short]");
731 			return -EBADMSG;
732 		}
733 		_leave(" = 0 [incomplete]");
734 		return 0;
735 	}
736 
737 	call->state = AFS_CALL_AWAIT_REQUEST;
738 
739 	/* ask the cache manager to route the call (it'll change the call type
740 	 * if successful) */
741 	if (!afs_cm_incoming_call(call))
742 		return -ENOTSUPP;
743 
744 	/* pass responsibility for the remainer of this message off to the
745 	 * cache manager op */
746 	return call->type->deliver(call, skb, last);
747 }
748 
749 /*
750  * send an empty reply
751  */
752 void afs_send_empty_reply(struct afs_call *call)
753 {
754 	struct msghdr msg;
755 	struct iovec iov[1];
756 
757 	_enter("");
758 
759 	iov[0].iov_base		= NULL;
760 	iov[0].iov_len		= 0;
761 	msg.msg_name		= NULL;
762 	msg.msg_namelen		= 0;
763 	msg.msg_iov		= iov;
764 	msg.msg_iovlen		= 0;
765 	msg.msg_control		= NULL;
766 	msg.msg_controllen	= 0;
767 	msg.msg_flags		= 0;
768 
769 	call->state = AFS_CALL_AWAIT_ACK;
770 	switch (rxrpc_kernel_send_data(call->rxcall, &msg, 0)) {
771 	case 0:
772 		_leave(" [replied]");
773 		return;
774 
775 	case -ENOMEM:
776 		_debug("oom");
777 		rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
778 	default:
779 		rxrpc_kernel_end_call(call->rxcall);
780 		call->rxcall = NULL;
781 		call->type->destructor(call);
782 		afs_free_call(call);
783 		_leave(" [error]");
784 		return;
785 	}
786 }
787 
788 /*
789  * send a simple reply
790  */
791 void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
792 {
793 	struct msghdr msg;
794 	struct iovec iov[1];
795 	int n;
796 
797 	_enter("");
798 
799 	iov[0].iov_base		= (void *) buf;
800 	iov[0].iov_len		= len;
801 	msg.msg_name		= NULL;
802 	msg.msg_namelen		= 0;
803 	msg.msg_iov		= iov;
804 	msg.msg_iovlen		= 1;
805 	msg.msg_control		= NULL;
806 	msg.msg_controllen	= 0;
807 	msg.msg_flags		= 0;
808 
809 	call->state = AFS_CALL_AWAIT_ACK;
810 	n = rxrpc_kernel_send_data(call->rxcall, &msg, len);
811 	if (n >= 0) {
812 		_leave(" [replied]");
813 		return;
814 	}
815 	if (n == -ENOMEM) {
816 		_debug("oom");
817 		rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
818 	}
819 	rxrpc_kernel_end_call(call->rxcall);
820 	call->rxcall = NULL;
821 	call->type->destructor(call);
822 	afs_free_call(call);
823 	_leave(" [error]");
824 }
825 
826 /*
827  * extract a piece of data from the received data socket buffers
828  */
829 int afs_extract_data(struct afs_call *call, struct sk_buff *skb,
830 		     bool last, void *buf, size_t count)
831 {
832 	size_t len = skb->len;
833 
834 	_enter("{%u},{%zu},%d,,%zu", call->offset, len, last, count);
835 
836 	ASSERTCMP(call->offset, <, count);
837 
838 	len = min_t(size_t, len, count - call->offset);
839 	if (skb_copy_bits(skb, 0, buf + call->offset, len) < 0 ||
840 	    !pskb_pull(skb, len))
841 		BUG();
842 	call->offset += len;
843 
844 	if (call->offset < count) {
845 		if (last) {
846 			_leave(" = -EBADMSG [%d < %zu]", call->offset, count);
847 			return -EBADMSG;
848 		}
849 		_leave(" = -EAGAIN");
850 		return -EAGAIN;
851 	}
852 	return 0;
853 }
854