summaryrefslogtreecommitdiff
path: root/net/rxrpc/io_thread.c
blob: 416c6101cf78150da0e60f6f5a673258791f50c4 (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
// SPDX-License-Identifier: GPL-2.0-or-later
/* RxRPC packet reception
 *
 * Copyright (C) 2007, 2016, 2022 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include "ar-internal.h"

/*
 * handle data received on the local endpoint
 * - may be called in interrupt context
 *
 * [!] Note that as this is called from the encap_rcv hook, the socket is not
 * held locked by the caller and nothing prevents sk_user_data on the UDP from
 * being cleared in the middle of processing this function.
 *
 * Called with the RCU read lock held from the IP layer via UDP.
 */
int rxrpc_encap_rcv(struct sock *udp_sk, struct sk_buff *skb)
{
	struct rxrpc_local *local = rcu_dereference_sk_user_data(udp_sk);

	if (unlikely(!local)) {
		kfree_skb(skb);
		return 0;
	}
	if (skb->tstamp == 0)
		skb->tstamp = ktime_get_real();

	skb->mark = RXRPC_SKB_MARK_PACKET;
	rxrpc_new_skb(skb, rxrpc_skb_new_encap_rcv);
	skb_queue_tail(&local->rx_queue, skb);
	rxrpc_wake_up_io_thread(local);
	return 0;
}

/*
 * Handle an error received on the local endpoint.
 */
void rxrpc_error_report(struct sock *sk)
{
	struct rxrpc_local *local;
	struct sk_buff *skb;

	rcu_read_lock();
	local = rcu_dereference_sk_user_data(sk);
	if (unlikely(!local)) {
		rcu_read_unlock();
		return;
	}

	while ((skb = skb_dequeue(&sk->sk_error_queue))) {
		skb->mark = RXRPC_SKB_MARK_ERROR;
		rxrpc_new_skb(skb, rxrpc_skb_new_error_report);
		skb_queue_tail(&local->rx_queue, skb);
	}

	rxrpc_wake_up_io_thread(local);
	rcu_read_unlock();
}

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

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

/*
 * 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);

	if (rxrpc_get_local_maybe(local, rxrpc_local_get_queue)) {
		skb_queue_tail(&local->event_queue, skb);
		rxrpc_queue_local(local);
	} else {
		rxrpc_free_skb(skb, rxrpc_skb_put_input);
	}
}

/*
 * put a packet up for transport-level abort
 */
static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
{
	if (rxrpc_get_local_maybe(local, rxrpc_local_get_queue)) {
		skb_queue_tail(&local->reject_queue, skb);
		rxrpc_queue_local(local);
	} else {
		rxrpc_free_skb(skb, rxrpc_skb_put_input);
	}
}

/*
 * Extract the wire header from a packet and translate the byte order.
 */
static noinline
int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
{
	struct rxrpc_wire_header whdr;

	/* dig out the RxRPC connection details */
	if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0) {
		trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
				      tracepoint_string("bad_hdr"));
		return -EBADMSG;
	}

	memset(sp, 0, sizeof(*sp));
	sp->hdr.epoch		= ntohl(whdr.epoch);
	sp->hdr.cid		= ntohl(whdr.cid);
	sp->hdr.callNumber	= ntohl(whdr.callNumber);
	sp->hdr.seq		= ntohl(whdr.seq);
	sp->hdr.serial		= ntohl(whdr.serial);
	sp->hdr.flags		= whdr.flags;
	sp->hdr.type		= whdr.type;
	sp->hdr.userStatus	= whdr.userStatus;
	sp->hdr.securityIndex	= whdr.securityIndex;
	sp->hdr._rsvd		= ntohs(whdr._rsvd);
	sp->hdr.serviceId	= ntohs(whdr.serviceId);
	return 0;
}

/*
 * Extract the abort code from an ABORT packet and stash it in skb->priority.
 */
static bool rxrpc_extract_abort(struct sk_buff *skb)
{
	__be32 wtmp;

	if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
			  &wtmp, sizeof(wtmp)) < 0)
		return false;
	skb->priority = ntohl(wtmp);
	return true;
}

/*
 * Process packets received on the local endpoint
 */
static int rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff *skb)
{
	struct rxrpc_connection *conn;
	struct rxrpc_channel *chan;
	struct rxrpc_call *call = NULL;
	struct rxrpc_skb_priv *sp;
	struct rxrpc_peer *peer = NULL;
	struct rxrpc_sock *rx = NULL;
	unsigned int channel;

	if (skb->tstamp == 0)
		skb->tstamp = ktime_get_real();

	skb_pull(skb, sizeof(struct udphdr));

	/* The UDP protocol already released all skb resources;
	 * we are free to add our own data there.
	 */
	sp = rxrpc_skb(skb);

	/* dig out the RxRPC connection details */
	if (rxrpc_extract_header(sp, skb) < 0)
		goto bad_message;

	if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
		static int lose;
		if ((lose++ & 7) == 7) {
			trace_rxrpc_rx_lose(sp);
			rxrpc_free_skb(skb, rxrpc_skb_put_lose);
			return 0;
		}
	}

	if (skb->tstamp == 0)
		skb->tstamp = ktime_get_real();
	trace_rxrpc_rx_packet(sp);

	switch (sp->hdr.type) {
	case RXRPC_PACKET_TYPE_VERSION:
		if (rxrpc_to_client(sp))
			goto discard;
		rxrpc_post_packet_to_local(local, skb);
		goto out;

	case RXRPC_PACKET_TYPE_BUSY:
		if (rxrpc_to_server(sp))
			goto discard;
		fallthrough;
	case RXRPC_PACKET_TYPE_ACK:
	case RXRPC_PACKET_TYPE_ACKALL:
		if (sp->hdr.callNumber == 0)
			goto bad_message;
		break;
	case RXRPC_PACKET_TYPE_ABORT:
		if (!rxrpc_extract_abort(skb))
			return true; /* Just discard if malformed */
		break;

	case RXRPC_PACKET_TYPE_DATA:
		if (sp->hdr.callNumber == 0 ||
		    sp->hdr.seq == 0)
			goto bad_message;

		/* Unshare the packet so that it can be modified for in-place
		 * decryption.
		 */
		if (sp->hdr.securityIndex != 0) {
			struct sk_buff *nskb = skb_unshare(skb, GFP_ATOMIC);
			if (!nskb) {
				rxrpc_eaten_skb(skb, rxrpc_skb_eaten_by_unshare_nomem);
				goto out;
			}

			if (nskb != skb) {
				rxrpc_eaten_skb(skb, rxrpc_skb_eaten_by_unshare);
				skb = nskb;
				rxrpc_new_skb(skb, rxrpc_skb_new_unshared);
				sp = rxrpc_skb(skb);
			}
		}
		break;

	case RXRPC_PACKET_TYPE_CHALLENGE:
		if (rxrpc_to_server(sp))
			goto discard;
		break;
	case RXRPC_PACKET_TYPE_RESPONSE:
		if (rxrpc_to_client(sp))
			goto discard;
		break;

		/* Packet types 9-11 should just be ignored. */
	case RXRPC_PACKET_TYPE_PARAMS:
	case RXRPC_PACKET_TYPE_10:
	case RXRPC_PACKET_TYPE_11:
		goto discard;

	default:
		goto bad_message;
	}

	if (sp->hdr.serviceId == 0)
		goto bad_message;

	if (rxrpc_to_server(sp)) {
		/* Weed out packets to services we're not offering.  Packets
		 * that would begin a call are explicitly rejected and the rest
		 * are just discarded.
		 */
		rx = rcu_dereference(local->service);
		if (!rx || (sp->hdr.serviceId != rx->srx.srx_service &&
			    sp->hdr.serviceId != rx->second_service)) {
			if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
			    sp->hdr.seq == 1)
				goto unsupported_service;
			goto discard;
		}
	}

	conn = rxrpc_find_connection_rcu(local, skb, &peer);
	if (conn) {
		if (sp->hdr.securityIndex != conn->security_ix)
			goto wrong_security;

		if (sp->hdr.serviceId != conn->service_id) {
			int old_id;

			if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags))
				goto reupgrade;
			old_id = cmpxchg(&conn->service_id, conn->orig_service_id,
					 sp->hdr.serviceId);

			if (old_id != conn->orig_service_id &&
			    old_id != sp->hdr.serviceId)
				goto reupgrade;
		}

		if (sp->hdr.callNumber == 0) {
			/* Connection-level packet */
			_debug("CONN %p {%d}", conn, conn->debug_id);
			rxrpc_post_packet_to_conn(conn, skb);
			goto out;
		}

		if ((int)sp->hdr.serial - (int)conn->hi_serial > 0)
			conn->hi_serial = sp->hdr.serial;

		/* Call-bound packets are routed by connection channel. */
		channel = sp->hdr.cid & RXRPC_CHANNELMASK;
		chan = &conn->channels[channel];

		/* Ignore really old calls */
		if (sp->hdr.callNumber < chan->last_call)
			goto discard;

		if (sp->hdr.callNumber == chan->last_call) {
			if (chan->call ||
			    sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)
				goto discard;

			/* For the previous service call, if completed
			 * successfully, we discard all further packets.
			 */
			if (rxrpc_conn_is_service(conn) &&
			    chan->last_type == RXRPC_PACKET_TYPE_ACK)
				goto discard;

			/* But otherwise we need to retransmit the final packet
			 * from data cached in the connection record.
			 */
			if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
				trace_rxrpc_rx_data(chan->call_debug_id,
						    sp->hdr.seq,
						    sp->hdr.serial,
						    sp->hdr.flags);
			rxrpc_post_packet_to_conn(conn, skb);
			goto out;
		}

		call = rcu_dereference(chan->call);

		if (sp->hdr.callNumber > chan->call_id) {
			if (rxrpc_to_client(sp))
				goto reject_packet;
			if (call)
				rxrpc_input_implicit_end_call(rx, conn, call);
			call = NULL;
		}

		if (call) {
			if (sp->hdr.serviceId != call->service_id)
				call->service_id = sp->hdr.serviceId;
			if ((int)sp->hdr.serial - (int)call->rx_serial > 0)
				call->rx_serial = sp->hdr.serial;
			if (!test_bit(RXRPC_CALL_RX_HEARD, &call->flags))
				set_bit(RXRPC_CALL_RX_HEARD, &call->flags);
		}
	}

	if (!call || refcount_read(&call->ref) == 0) {
		if (rxrpc_to_client(sp) ||
		    sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
			goto bad_message;
		if (sp->hdr.seq != 1)
			goto discard;
		call = rxrpc_new_incoming_call(local, rx, skb);
		if (!call)
			goto reject_packet;
	}

	/* Process a call packet; this either discards or passes on the ref
	 * elsewhere.
	 */
	rxrpc_input_call_packet(call, skb);
	goto out;

discard:
	rxrpc_free_skb(skb, rxrpc_skb_put_input);
out:
	trace_rxrpc_rx_done(0, 0);
	return 0;

wrong_security:
	trace_rxrpc_abort(0, "SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
			  RXKADINCONSISTENCY, EBADMSG);
	skb->priority = RXKADINCONSISTENCY;
	goto post_abort;

unsupported_service:
	trace_rxrpc_abort(0, "INV", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
			  RX_INVALID_OPERATION, EOPNOTSUPP);
	skb->priority = RX_INVALID_OPERATION;
	goto post_abort;

reupgrade:
	trace_rxrpc_abort(0, "UPG", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
			  RX_PROTOCOL_ERROR, EBADMSG);
	goto protocol_error;

bad_message:
	trace_rxrpc_abort(0, "BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
			  RX_PROTOCOL_ERROR, EBADMSG);
protocol_error:
	skb->priority = RX_PROTOCOL_ERROR;
post_abort:
	skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
reject_packet:
	trace_rxrpc_rx_done(skb->mark, skb->priority);
	rxrpc_reject_packet(local, skb);
	_leave(" [badmsg]");
	return 0;
}

/*
 * I/O and event handling thread.
 */
int rxrpc_io_thread(void *data)
{
	struct sk_buff_head rx_queue;
	struct rxrpc_local *local = data;
	struct sk_buff *skb;

	skb_queue_head_init(&rx_queue);

	set_user_nice(current, MIN_NICE);

	for (;;) {
		rxrpc_inc_stat(local->rxnet, stat_io_loop);

		/* Process received packets and errors. */
		if ((skb = __skb_dequeue(&rx_queue))) {
			switch (skb->mark) {
			case RXRPC_SKB_MARK_PACKET:
				rcu_read_lock();
				rxrpc_input_packet(local, skb);
				rcu_read_unlock();
				break;
			case RXRPC_SKB_MARK_ERROR:
				rxrpc_input_error(local, skb);
				rxrpc_free_skb(skb, rxrpc_skb_put_error_report);
				break;
			default:
				WARN_ON_ONCE(1);
				rxrpc_free_skb(skb, rxrpc_skb_put_unknown);
				break;
			}
			continue;
		}

		if (!skb_queue_empty(&local->rx_queue)) {
			spin_lock_irq(&local->rx_queue.lock);
			skb_queue_splice_tail_init(&local->rx_queue, &rx_queue);
			spin_unlock_irq(&local->rx_queue.lock);
			continue;
		}

		set_current_state(TASK_INTERRUPTIBLE);
		if (!skb_queue_empty(&local->rx_queue)) {
			__set_current_state(TASK_RUNNING);
			continue;
		}

		if (kthread_should_stop())
			break;
		schedule();
	}

	__set_current_state(TASK_RUNNING);
	rxrpc_see_local(local, rxrpc_local_stop);
	rxrpc_destroy_local(local);
	local->io_thread = NULL;
	rxrpc_see_local(local, rxrpc_local_stopped);
	return 0;
}