summaryrefslogtreecommitdiffstats
path: root/net/rxrpc/ar-input.c
blob: 4505a691d88c283bbbd8038c2dd088825015bd32 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
/* RxRPC packet reception
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/errqueue.h>
#include <linux/udp.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/icmp.h>
#include <linux/gfp.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <net/ip.h>
#include <net/udp.h>
#include <net/net_namespace.h>
#include "ar-internal.h"

const char *rxrpc_pkts[] = {
	"?00",
	"DATA", "ACK", "BUSY", "ABORT", "ACKALL", "CHALL", "RESP", "DEBUG",
	"?09", "?10", "?11", "?12", "VERSION", "?14", "?15"
};

/*
 * queue a packet for recvmsg to pass to userspace
 * - the caller must hold a lock on call->lock
 * - must not be called with interrupts disabled (sk_filter() disables BH's)
 * - eats the packet whether successful or not
 * - there must be just one reference to the packet, which the caller passes to
 *   this function
 */
int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
			bool force, bool terminal)
{
	struct rxrpc_skb_priv *sp;
	struct rxrpc_sock *rx = call->socket;
	struct sock *sk;
	int ret;

	_enter(",,%d,%d", force, terminal);

	ASSERT(!irqs_disabled());

	sp = rxrpc_skb(skb);
	ASSERTCMP(sp->call, ==, call);

	/* if we've already posted the terminal message for a call, then we
	 * don't post any more */
	if (test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
		_debug("already terminated");
		ASSERTCMP(call->state, >=, RXRPC_CALL_COMPLETE);
		skb->destructor = NULL;
		sp->call = NULL;
		rxrpc_put_call(call);
		rxrpc_free_skb(skb);
		return 0;
	}

	sk = &rx->sk;

	if (!force) {
		/* cast skb->rcvbuf to unsigned...  It's pointless, but
		 * reduces number of warnings when compiling with -W
		 * --ANK */
//		ret = -ENOBUFS;
//		if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
//		    (unsigned int) sk->sk_rcvbuf)
//			goto out;

		ret = sk_filter(sk, skb);
		if (ret < 0)
			goto out;
	}

	spin_lock_bh(&sk->sk_receive_queue.lock);
	if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags) &&
	    !test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
	    call->socket->sk.sk_state != RXRPC_CLOSE) {
		skb->destructor = rxrpc_packet_destructor;
		skb->dev = NULL;
		skb->sk = sk;
		atomic_add(skb->truesize, &sk->sk_rmem_alloc);

		if (terminal) {
			_debug("<<<< TERMINAL MESSAGE >>>>");
			set_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags);
		}

		/* allow interception by a kernel service */
		if (rx->interceptor) {
			rx->interceptor(sk, call->user_call_ID, skb);
			spin_unlock_bh(&sk->sk_receive_queue.lock);
		} else {
			_net("post skb %p", skb);
			__skb_queue_tail(&sk->sk_receive_queue, skb);
			spin_unlock_bh(&sk->sk_receive_queue.lock);

			if (!sock_flag(sk, SOCK_DEAD))
				sk->sk_data_ready(sk);
		}
		skb = NULL;
	} else {
		spin_unlock_bh(&sk->sk_receive_queue.lock);
	}
	ret = 0;

out:
	/* release the socket buffer */
	if (skb) {
		skb->destructor = NULL;
		sp->call = NULL;
		rxrpc_put_call(call);
		rxrpc_free_skb(skb);
	}

	_leave(" = %d", ret);
	return ret;
}

/*
 * process a DATA packet, posting the packet to the appropriate queue
 * - eats the packet if successful
 */
static int rxrpc_fast_process_data(struct rxrpc_call *call,
				   struct sk_buff *skb, u32 seq)
{
	struct rxrpc_skb_priv *sp;
	bool terminal;
	int ret, ackbit, ack;

	_enter("{%u,%u},,{%u}", call->rx_data_post, call->rx_first_oos, seq);

	sp = rxrpc_skb(skb);
	ASSERTCMP(sp->call, ==, NULL);

	spin_lock(&call->lock);

	if (call->state > RXRPC_CALL_COMPLETE)
		goto discard;

	ASSERTCMP(call->rx_data_expect, >=, call->rx_data_post);
	ASSERTCMP(call->rx_data_post, >=, call->rx_data_recv);
	ASSERTCMP(call->rx_data_recv, >=, call->rx_data_eaten);

	if (seq < call->rx_data_post) {
		_debug("dup #%u [-%u]", seq, call->rx_data_post);
		ack = RXRPC_ACK_DUPLICATE;
		ret = -ENOBUFS;
		goto discard_and_ack;
	}

	/* we may already have the packet in the out of sequence queue */
	ackbit = seq - (call->rx_data_eaten + 1);
	ASSERTCMP(ackbit, >=, 0);
	if (__test_and_set_bit(ackbit, call->ackr_window)) {
		_debug("dup oos #%u [%u,%u]",
		       seq, call->rx_data_eaten, call->rx_data_post);
		ack = RXRPC_ACK_DUPLICATE;
		goto discard_and_ack;
	}

	if (seq >= call->ackr_win_top) {
		_debug("exceed #%u [%u]", seq, call->ackr_win_top);
		__clear_bit(ackbit, call->ackr_window);
		ack = RXRPC_ACK_EXCEEDS_WINDOW;
		goto discard_and_ack;
	}

	if (seq == call->rx_data_expect) {
		clear_bit(RXRPC_CALL_EXPECT_OOS, &call->flags);
		call->rx_data_expect++;
	} else if (seq > call->rx_data_expect) {
		_debug("oos #%u [%u]", seq, call->rx_data_expect);
		call->rx_data_expect = seq + 1;
		if (test_and_set_bit(RXRPC_CALL_EXPECT_OOS, &call->flags)) {
			ack = RXRPC_ACK_OUT_OF_SEQUENCE;
			goto enqueue_and_ack;
		}
		goto enqueue_packet;
	}

	if (seq != call->rx_data_post) {
		_debug("ahead #%u [%u]", seq, call->rx_data_post);
		goto enqueue_packet;
	}

	if (test_bit(RXRPC_CALL_RCVD_LAST, &call->flags))
		goto protocol_error;

	/* if the packet need security things doing to it, then it goes down
	 * the slow path */
	if (call->conn->security)
		goto enqueue_packet;

	sp->call = call;
	rxrpc_get_call(call);
	terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
		    !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
	ret = rxrpc_queue_rcv_skb(call, skb, false, terminal);
	if (ret < 0) {
		if (ret == -ENOMEM || ret == -ENOBUFS) {
			__clear_bit(ackbit, call->ackr_window);
			ack = RXRPC_ACK_NOSPACE;
			goto discard_and_ack;
		}
		goto out;
	}

	skb = NULL;

	_debug("post #%u", seq);
	ASSERTCMP(call->rx_data_post, ==, seq);
	call->rx_data_post++;

	if (sp->hdr.flags & RXRPC_LAST_PACKET)
		set_bit(RXRPC_CALL_RCVD_LAST, &call->flags);

	/* if we've reached an out of sequence packet then we need to drain
	 * that queue into the socket Rx queue now */
	if (call->rx_data_post == call->rx_first_oos) {
		_debug("drain rx oos now");
		read_lock(&call->state_lock);
		if (call->state < RXRPC_CALL_COMPLETE &&
		    !test_and_set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events))
			rxrpc_queue_call(call);
		read_unlock(&call->state_lock);
	}

	spin_unlock(&call->lock);
	atomic_inc(&call->ackr_not_idle);
	rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, sp->hdr.serial, false);
	_leave(" = 0 [posted]");
	return 0;

protocol_error:
	ret = -EBADMSG;
out:
	spin_unlock(&call->lock);
	_leave(" = %d", ret);
	return ret;

discard_and_ack:
	_debug("discard and ACK packet %p", skb);
	__rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
discard:
	spin_unlock(&call->lock);
	rxrpc_free_skb(skb);
	_leave(" = 0 [discarded]");
	return 0;

enqueue_and_ack:
	__rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
enqueue_packet:
	_net("defer skb %p", skb);
	spin_unlock(&call->lock);
	skb_queue_tail(&call->rx_queue, skb);
	atomic_inc(&call->ackr_not_idle);
	read_lock(&call->state_lock);
	if (call->state < RXRPC_CALL_DEAD)
		rxrpc_queue_call(call);
	read_unlock(&call->state_lock);
	_leave(" = 0 [queued]");
	return 0;
}

/*
 * assume an implicit ACKALL of the transmission phase of a client socket upon
 * reception of the first reply packet
 */
static void rxrpc_assume_implicit_ackall(struct rxrpc_call *call, u32 serial)
{
	write_lock_bh(&call->state_lock);

	switch (call->state) {
	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
		call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
		call->acks_latest = serial;

		_debug("implicit ACKALL %%%u", call->acks_latest);
		set_bit(RXRPC_CALL_RCVD_ACKALL, &call->events);
		write_unlock_bh(&call->state_lock);

		if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
			clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
			clear_bit(RXRPC_CALL_RESEND, &call->events);
			clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
		}
		break;

	default:
		write_unlock_bh(&call->state_lock);
		break;
	}
}

/*
 * post an incoming packet to the nominated call to deal with
 * - must get rid of the sk_buff, either by freeing it or by queuing it
 */
void rxrpc_fast_process_packet(struct rxrpc_call *call, struct sk_buff *skb)
{
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
	__be32 _abort_code;
	u32 serial, hi_serial, seq, abort_code;

	_enter("%p,%p", call, skb);

	ASSERT(!irqs_disabled());

#if 0 // INJECT RX ERROR
	if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
		static int skip = 0;
		if (++skip == 3) {
			printk("DROPPED 3RD PACKET!!!!!!!!!!!!!\n");
			skip = 0;
			goto free_packet;
		}
	}
#endif

	/* track the latest serial number on this connection for ACK packet
	 * information */
	serial = ntohl(sp->hdr.serial);
	hi_serial = atomic_read(&call->conn->hi_serial);
	while (serial > hi_serial)
		hi_serial = atomic_cmpxchg(&call->conn->hi_serial, hi_serial,
					   serial);

	/* request ACK generation for any ACK or DATA packet that requests
	 * it */
	if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
		_proto("ACK Requested on %%%u", serial);
		rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, sp->hdr.serial, false);
	}

	switch (sp->hdr.type) {
	case RXRPC_PACKET_TYPE_ABORT:
		_debug("abort");

		if (skb_copy_bits(skb, 0, &_abort_code,
				  sizeof(_abort_code)) < 0)
			goto protocol_error;

		abort_code = ntohl(_abort_code);
		_proto("Rx ABORT %%%u { %x }", serial, abort_code);

		write_lock_bh(&call->state_lock);
		if (call->state < RXRPC_CALL_COMPLETE) {
			call->state = RXRPC_CALL_REMOTELY_ABORTED;
			call->abort_code = abort_code;
			set_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
			rxrpc_queue_call(call);
		}
		goto free_packet_unlock;

	case RXRPC_PACKET_TYPE_BUSY:
		_proto("Rx BUSY %%%u", serial);

		if (call->conn->out_clientflag)
			goto protocol_error;

		write_lock_bh(&call->state_lock);
		switch (call->state) {
		case RXRPC_CALL_CLIENT_SEND_REQUEST:
			call->state = RXRPC_CALL_SERVER_BUSY;
			set_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
			rxrpc_queue_call(call);
		case RXRPC_CALL_SERVER_BUSY:
			goto free_packet_unlock;
		default:
			goto protocol_error_locked;
		}

	default:
		_proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], serial);
		goto protocol_error;

	case RXRPC_PACKET_TYPE_DATA:
		seq = ntohl(sp->hdr.seq);

		_proto("Rx DATA %%%u { #%u }", serial, seq);

		if (seq == 0)
			goto protocol_error;

		call->ackr_prev_seq = sp->hdr.seq;

		/* received data implicitly ACKs all of the request packets we
		 * sent when we're acting as a client */
		if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
			rxrpc_assume_implicit_ackall(call, serial);

		switch (rxrpc_fast_process_data(call, skb, seq)) {
		case 0:
			skb = NULL;
			goto done;

		default:
			BUG();

			/* data packet received beyond the last packet */
		case -EBADMSG:
			goto protocol_error;
		}

	case RXRPC_PACKET_TYPE_ACKALL:
	case RXRPC_PACKET_TYPE_ACK:
		/* ACK processing is done in process context */
		read_lock_bh(&call->state_lock);
		if (call->state < RXRPC_CALL_DEAD) {
			skb_queue_tail(&call->rx_queue, skb);
			rxrpc_queue_call(call);
			skb = NULL;
		}
		read_unlock_bh(&call->state_lock);
		goto free_packet;
	}

protocol_error:
	_debug("protocol error");
	write_lock_bh(&call->state_lock);
protocol_error_locked:
	if (call->state <= RXRPC_CALL_COMPLETE) {
		call->state = RXRPC_CALL_LOCALLY_ABORTED;
		call->abort_code = RX_PROTOCOL_ERROR;
		set_bit(RXRPC_CALL_ABORT, &call->events);
		rxrpc_queue_call(call);
	}
free_packet_unlock:
	write_unlock_bh(&call->state_lock);
free_packet:
	rxrpc_free_skb(skb);
done:
	_leave("");
}

/*
 * split up a jumbo data packet
 */
static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
				       struct sk_buff *jumbo)
{
	struct rxrpc_jumbo_header jhdr;
	struct rxrpc_skb_priv *sp;
	struct sk_buff *part;

	_enter(",{%u,%u}", jumbo->data_len, jumbo->len);

	sp = rxrpc_skb(jumbo);

	do {
		sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;

		/* make a clone to represent the first subpacket in what's left
		 * of the jumbo packet */
		part = skb_clone(jumbo, GFP_ATOMIC);
		if (!part) {
			/* simply ditch the tail in the event of ENOMEM */
			pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
			break;
		}
		rxrpc_new_skb(part);

		pskb_trim(part, RXRPC_JUMBO_DATALEN);

		if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
			goto protocol_error;

		if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
			goto protocol_error;
		if (!pskb_pull(jumbo, sizeof(jhdr)))
			BUG();

		sp->hdr.seq	= htonl(ntohl(sp->hdr.seq) + 1);
		sp->hdr.serial	= htonl(ntohl(sp->hdr.serial) + 1);
		sp->hdr.flags	= jhdr.flags;
		sp->hdr._rsvd	= jhdr._rsvd;

		_proto("Rx DATA Jumbo %%%u", ntohl(sp->hdr.serial) - 1);

		rxrpc_fast_process_packet(call, part);
		part = NULL;

	} while (sp->hdr.flags & RXRPC_JUMBO_PACKET);

	rxrpc_fast_process_packet(call, jumbo);
	_leave("");
	return;

protocol_error:
	_debug("protocol error");
	rxrpc_free_skb(part);
	rxrpc_free_skb(jumbo);
	write_lock_bh(&call->state_lock);
	if (call->state <= RXRPC_CALL_COMPLETE) {
		call->state = RXRPC_CALL_LOCALLY_ABORTED;
		call->abort_code = RX_PROTOCOL_ERROR;
		set_bit(RXRPC_CALL_ABORT, &call->events);
		rxrpc_queue_call(call);
	}
	write_unlock_bh(&call->state_lock);
	_leave("");
}

/*
 * post an incoming packet to the appropriate call/socket to deal with
 * - must get rid of the sk_buff, either by freeing it or by queuing it
 */
static void rxrpc_post_packet_to_call(struct rxrpc_call *call,
				      struct sk_buff *skb)
{
	struct rxrpc_skb_priv *sp;

	_enter("%p,%p", call, skb);

	sp = rxrpc_skb(skb);

	_debug("extant call [%d]", call->state);

	read_lock(&call->state_lock);
	switch (call->state) {
	case RXRPC_CALL_LOCALLY_ABORTED:
		if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events)) {
			rxrpc_queue_call(call);
			goto free_unlock;
		}
	case RXRPC_CALL_REMOTELY_ABORTED:
	case RXRPC_CALL_NETWORK_ERROR:
	case RXRPC_CALL_DEAD:
		goto dead_call;
	case RXRPC_CALL_COMPLETE:
	case RXRPC_CALL_CLIENT_FINAL_ACK:
		/* complete server call */
		if (call->conn->in_clientflag)
			goto dead_call;
		/* resend last packet of a completed call */
		_debug("final ack again");
		rxrpc_get_call(call);
		set_bit(RXRPC_CALL_ACK_FINAL, &call->events);
		rxrpc_queue_call(call);
		goto free_unlock;
	default:
		break;
	}

	read_unlock(&call->state_lock);
	rxrpc_get_call(call);

	if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
	    sp->hdr.flags & RXRPC_JUMBO_PACKET)
		rxrpc_process_jumbo_packet(call, skb);
	else
		rxrpc_fast_process_packet(call, skb);

	rxrpc_put_call(call);
	goto done;

dead_call:
	if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
		skb->priority = RX_CALL_DEAD;
		rxrpc_reject_packet(call->conn->trans->local, skb);
		goto unlock;
	}
free_unlock:
	rxrpc_free_skb(skb);
unlock:
	read_unlock(&call->state_lock);
done:
	_leave("");
}

/*
 * post connection-level events to the connection
 * - this includes challenges, responses and some aborts
 */
static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
				      struct sk_buff *skb)
{
	_enter("%p,%p", conn, skb);

	atomic_inc(&conn->usage);
	skb_queue_tail(&conn->rx_queue, skb);
	rxrpc_queue_conn(conn);
}

/*
 * post endpoint-level events to the local endpoint
 * - this includes debug and version messages
 */
static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
				       struct sk_buff *skb)
{
	_enter("%p,%p", local, skb);

	atomic_inc(&local->usage);
	skb_queue_tail(&local->event_queue, skb);
	rxrpc_queue_work(&local->event_processor);
}

static struct rxrpc_connection *rxrpc_conn_from_local(struct rxrpc_local *local,
					       struct sk_buff *skb,
					       struct rxrpc_skb_priv *sp)
{
	struct rxrpc_peer *peer;
	struct rxrpc_transport *trans;
	struct rxrpc_connection *conn;

	peer = rxrpc_find_peer(local, ip_hdr(skb)->saddr,
				udp_hdr(skb)->source);
	if (IS_ERR(peer))
		goto cant_find_conn;

	trans = rxrpc_find_transport(local, peer);
	rxrpc_put_peer(peer);
	if (!trans)
		goto cant_find_conn;

	conn = rxrpc_find_connection(trans, &sp->hdr);
	rxrpc_put_transport(trans);
	if (!conn)
		goto cant_find_conn;

	return conn;
cant_find_conn:
	return NULL;
}

/*
 * handle data received on the local endpoint
 * - may be called in interrupt context
 */
void rxrpc_data_ready(struct sock *sk)
{
	struct rxrpc_skb_priv *sp;
	struct rxrpc_local *local;
	struct sk_buff *skb;
	int ret;

	_enter("%p", sk);

	ASSERT(!irqs_disabled());

	read_lock_bh(&rxrpc_local_lock);
	local = sk->sk_user_data;
	if (local && atomic_read(&local->usage) > 0)
		rxrpc_get_local(local);
	else
		local = NULL;
	read_unlock_bh(&rxrpc_local_lock);
	if (!local) {
		_leave(" [local dead]");
		return;
	}

	skb = skb_recv_datagram(sk, 0, 1, &ret);
	if (!skb) {
		rxrpc_put_local(local);
		if (ret == -EAGAIN)
			return;
		_debug("UDP socket error %d", ret);
		return;
	}

	rxrpc_new_skb(skb);

	_net("recv skb %p", skb);

	/* we'll probably need to checksum it (didn't call sock_recvmsg) */
	if (skb_checksum_complete(skb)) {
		rxrpc_free_skb(skb);
		rxrpc_put_local(local);
		UDP_INC_STATS_BH(&init_net, UDP_MIB_INERRORS, 0);
		_leave(" [CSUM failed]");
		return;
	}

	UDP_INC_STATS_BH(&init_net, UDP_MIB_INDATAGRAMS, 0);

	/* the socket buffer we have is owned by UDP, with UDP's data all over
	 * it, but we really want our own */
	skb_orphan(skb);
	sp = rxrpc_skb(skb);
	memset(sp, 0, sizeof(*sp));

	_net("Rx UDP packet from %08x:%04hu",
	     ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));

	/* dig out the RxRPC connection details */
	if (skb_copy_bits(skb, sizeof(struct udphdr), &sp->hdr,
			  sizeof(sp->hdr)) < 0)
		goto bad_message;
	if (!pskb_pull(skb, sizeof(struct udphdr) + sizeof(sp->hdr)))
		BUG();

	_net("Rx RxRPC %s ep=%x call=%x:%x",
	     sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
	     ntohl(sp->hdr.epoch),
	     ntohl(sp->hdr.cid),
	     ntohl(sp->hdr.callNumber));

	if (sp->hdr.type == 0 || sp->hdr.type >= RXRPC_N_PACKET_TYPES) {
		_proto("Rx Bad Packet Type %u", sp->hdr.type);
		goto bad_message;
	}

	if (sp->hdr.type == RXRPC_PACKET_TYPE_VERSION) {
		rxrpc_post_packet_to_local(local, skb);
		goto out;
	}
	
	if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
	    (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
		goto bad_message;

	if (sp->hdr.callNumber == 0) {
		/* This is a connection-level packet. These should be
		 * fairly rare, so the extra overhead of looking them up the
		 * old-fashioned way doesn't really hurt */
		struct rxrpc_connection *conn;

		conn = rxrpc_conn_from_local(local, skb, sp);
		if (!conn)
			goto cant_route_call;

		_debug("CONN %p {%d}", conn, conn->debug_id);
		rxrpc_post_packet_to_conn(conn, skb);
		rxrpc_put_connection(conn);
	} else {
		struct rxrpc_call *call;
		u8 in_clientflag = 0;

		if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
			in_clientflag = RXRPC_CLIENT_INITIATED;
		call = rxrpc_find_call_hash(in_clientflag, sp->hdr.cid,
					    sp->hdr.callNumber, sp->hdr.epoch,
					    sp->hdr.serviceId, local, AF_INET,
					    (u8 *)&ip_hdr(skb)->saddr);
		if (call)
			rxrpc_post_packet_to_call(call, skb);
		else
			goto cant_route_call;
	}

out:
	rxrpc_put_local(local);
	return;

cant_route_call:
	_debug("can't route call");
	if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
	    sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
		if (sp->hdr.seq == cpu_to_be32(1)) {
			_debug("first packet");
			skb_queue_tail(&local->accept_queue, skb);
			rxrpc_queue_work(&local->acceptor);
			rxrpc_put_local(local);
			_leave(" [incoming]");
			return;
		}
		skb->priority = RX_INVALID_OPERATION;
	} else {
		skb->priority = RX_CALL_DEAD;
	}

	if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
		_debug("reject type %d",sp->hdr.type);
		rxrpc_reject_packet(local, skb);
	}
	rxrpc_put_local(local);
	_leave(" [no call]");
	return;

bad_message:
	skb->priority = RX_PROTOCOL_ERROR;
	rxrpc_reject_packet(local, skb);
	rxrpc_put_local(local);
	_leave(" [badmsg]");
}
OpenPOWER on IntegriCloud