1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* RxRPC packet reception
3 *
4 * Copyright (C) 2007, 2016, 2022 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells ([email protected])
6 */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include "ar-internal.h"
11
12 static int rxrpc_input_packet_on_conn(struct rxrpc_connection *conn,
13 struct sockaddr_rxrpc *peer_srx,
14 struct sk_buff *skb);
15
16 /*
17 * handle data received on the local endpoint
18 * - may be called in interrupt context
19 *
20 * [!] Note that as this is called from the encap_rcv hook, the socket is not
21 * held locked by the caller and nothing prevents sk_user_data on the UDP from
22 * being cleared in the middle of processing this function.
23 *
24 * Called with the RCU read lock held from the IP layer via UDP.
25 */
rxrpc_encap_rcv(struct sock * udp_sk,struct sk_buff * skb)26 int rxrpc_encap_rcv(struct sock *udp_sk, struct sk_buff *skb)
27 {
28 struct sk_buff_head *rx_queue;
29 struct rxrpc_local *local = rcu_dereference_sk_user_data(udp_sk);
30 struct task_struct *io_thread;
31
32 if (unlikely(!local)) {
33 kfree_skb(skb);
34 return 0;
35 }
36 io_thread = READ_ONCE(local->io_thread);
37 if (!io_thread) {
38 kfree_skb(skb);
39 return 0;
40 }
41 if (skb->tstamp == 0)
42 skb->tstamp = ktime_get_real();
43
44 skb->mark = RXRPC_SKB_MARK_PACKET;
45 rxrpc_new_skb(skb, rxrpc_skb_new_encap_rcv);
46 rx_queue = &local->rx_queue;
47 #ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
48 if (rxrpc_inject_rx_delay ||
49 !skb_queue_empty(&local->rx_delay_queue)) {
50 skb->tstamp = ktime_add_ms(skb->tstamp, rxrpc_inject_rx_delay);
51 rx_queue = &local->rx_delay_queue;
52 }
53 #endif
54
55 skb_queue_tail(rx_queue, skb);
56 wake_up_process(io_thread);
57 return 0;
58 }
59
60 /*
61 * Handle an error received on the local endpoint.
62 */
rxrpc_error_report(struct sock * sk)63 void rxrpc_error_report(struct sock *sk)
64 {
65 struct rxrpc_local *local;
66 struct sk_buff *skb;
67
68 rcu_read_lock();
69 local = rcu_dereference_sk_user_data(sk);
70 if (unlikely(!local)) {
71 rcu_read_unlock();
72 return;
73 }
74
75 while ((skb = skb_dequeue(&sk->sk_error_queue))) {
76 skb->mark = RXRPC_SKB_MARK_ERROR;
77 rxrpc_new_skb(skb, rxrpc_skb_new_error_report);
78 skb_queue_tail(&local->rx_queue, skb);
79 }
80
81 rxrpc_wake_up_io_thread(local);
82 rcu_read_unlock();
83 }
84
85 /*
86 * Directly produce an abort from a packet.
87 */
rxrpc_direct_abort(struct sk_buff * skb,enum rxrpc_abort_reason why,s32 abort_code,int err)88 bool rxrpc_direct_abort(struct sk_buff *skb, enum rxrpc_abort_reason why,
89 s32 abort_code, int err)
90 {
91 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
92
93 trace_rxrpc_abort(0, why, sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
94 abort_code, err);
95 skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
96 skb->priority = abort_code;
97 return false;
98 }
99
rxrpc_bad_message(struct sk_buff * skb,enum rxrpc_abort_reason why)100 static bool rxrpc_bad_message(struct sk_buff *skb, enum rxrpc_abort_reason why)
101 {
102 return rxrpc_direct_abort(skb, why, RX_PROTOCOL_ERROR, -EBADMSG);
103 }
104
105 #define just_discard true
106
107 /*
108 * Process event packets targeted at a local endpoint.
109 */
rxrpc_input_version(struct rxrpc_local * local,struct sk_buff * skb)110 static bool rxrpc_input_version(struct rxrpc_local *local, struct sk_buff *skb)
111 {
112 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
113 char v;
114
115 _enter("");
116
117 rxrpc_see_skb(skb, rxrpc_skb_see_version);
118 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header), &v, 1) >= 0) {
119 if (v == 0)
120 rxrpc_send_version_request(local, &sp->hdr, skb);
121 }
122
123 return true;
124 }
125
126 /*
127 * Extract the wire header from a packet and translate the byte order.
128 */
rxrpc_extract_header(struct rxrpc_skb_priv * sp,struct sk_buff * skb)129 static bool rxrpc_extract_header(struct rxrpc_skb_priv *sp,
130 struct sk_buff *skb)
131 {
132 struct rxrpc_wire_header whdr;
133 struct rxrpc_ackpacket ack;
134
135 /* dig out the RxRPC connection details */
136 if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
137 return rxrpc_bad_message(skb, rxrpc_badmsg_short_hdr);
138
139 memset(sp, 0, sizeof(*sp));
140 sp->hdr.epoch = ntohl(whdr.epoch);
141 sp->hdr.cid = ntohl(whdr.cid);
142 sp->hdr.callNumber = ntohl(whdr.callNumber);
143 sp->hdr.seq = ntohl(whdr.seq);
144 sp->hdr.serial = ntohl(whdr.serial);
145 sp->hdr.flags = whdr.flags;
146 sp->hdr.type = whdr.type;
147 sp->hdr.userStatus = whdr.userStatus;
148 sp->hdr.securityIndex = whdr.securityIndex;
149 sp->hdr._rsvd = ntohs(whdr._rsvd);
150 sp->hdr.serviceId = ntohs(whdr.serviceId);
151
152 if (sp->hdr.type == RXRPC_PACKET_TYPE_ACK) {
153 if (skb_copy_bits(skb, sizeof(whdr), &ack, sizeof(ack)) < 0)
154 return rxrpc_bad_message(skb, rxrpc_badmsg_short_ack);
155 sp->ack.first_ack = ntohl(ack.firstPacket);
156 sp->ack.prev_ack = ntohl(ack.previousPacket);
157 sp->ack.acked_serial = ntohl(ack.serial);
158 sp->ack.reason = ack.reason;
159 sp->ack.nr_acks = ack.nAcks;
160 }
161 return true;
162 }
163
164 /*
165 * Extract the abort code from an ABORT packet and stash it in skb->priority.
166 */
rxrpc_extract_abort(struct sk_buff * skb)167 static bool rxrpc_extract_abort(struct sk_buff *skb)
168 {
169 __be32 wtmp;
170
171 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
172 &wtmp, sizeof(wtmp)) < 0)
173 return false;
174 skb->priority = ntohl(wtmp);
175 return true;
176 }
177
178 /*
179 * Process packets received on the local endpoint
180 */
rxrpc_input_packet(struct rxrpc_local * local,struct sk_buff ** _skb)181 static bool rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff **_skb)
182 {
183 struct rxrpc_connection *conn;
184 struct sockaddr_rxrpc peer_srx;
185 struct rxrpc_skb_priv *sp;
186 struct rxrpc_peer *peer = NULL;
187 struct sk_buff *skb = *_skb;
188 bool ret = false;
189
190 skb_pull(skb, sizeof(struct udphdr));
191
192 sp = rxrpc_skb(skb);
193
194 /* dig out the RxRPC connection details */
195 if (!rxrpc_extract_header(sp, skb))
196 return just_discard;
197
198 if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
199 static int lose;
200 if ((lose++ & 7) == 7) {
201 trace_rxrpc_rx_lose(sp);
202 return just_discard;
203 }
204 }
205
206 trace_rxrpc_rx_packet(sp);
207
208 switch (sp->hdr.type) {
209 case RXRPC_PACKET_TYPE_VERSION:
210 if (rxrpc_to_client(sp))
211 return just_discard;
212 return rxrpc_input_version(local, skb);
213
214 case RXRPC_PACKET_TYPE_BUSY:
215 if (rxrpc_to_server(sp))
216 return just_discard;
217 fallthrough;
218 case RXRPC_PACKET_TYPE_ACK:
219 case RXRPC_PACKET_TYPE_ACKALL:
220 if (sp->hdr.callNumber == 0)
221 return rxrpc_bad_message(skb, rxrpc_badmsg_zero_call);
222 break;
223 case RXRPC_PACKET_TYPE_ABORT:
224 if (!rxrpc_extract_abort(skb))
225 return just_discard; /* Just discard if malformed */
226 break;
227
228 case RXRPC_PACKET_TYPE_DATA:
229 if (sp->hdr.callNumber == 0)
230 return rxrpc_bad_message(skb, rxrpc_badmsg_zero_call);
231 if (sp->hdr.seq == 0)
232 return rxrpc_bad_message(skb, rxrpc_badmsg_zero_seq);
233
234 /* Unshare the packet so that it can be modified for in-place
235 * decryption.
236 */
237 if (sp->hdr.securityIndex != 0) {
238 skb = skb_unshare(skb, GFP_ATOMIC);
239 if (!skb) {
240 rxrpc_eaten_skb(*_skb, rxrpc_skb_eaten_by_unshare_nomem);
241 *_skb = NULL;
242 return just_discard;
243 }
244
245 if (skb != *_skb) {
246 rxrpc_eaten_skb(*_skb, rxrpc_skb_eaten_by_unshare);
247 *_skb = skb;
248 rxrpc_new_skb(skb, rxrpc_skb_new_unshared);
249 sp = rxrpc_skb(skb);
250 }
251 }
252 break;
253
254 case RXRPC_PACKET_TYPE_CHALLENGE:
255 if (rxrpc_to_server(sp))
256 return just_discard;
257 break;
258 case RXRPC_PACKET_TYPE_RESPONSE:
259 if (rxrpc_to_client(sp))
260 return just_discard;
261 break;
262
263 /* Packet types 9-11 should just be ignored. */
264 case RXRPC_PACKET_TYPE_PARAMS:
265 case RXRPC_PACKET_TYPE_10:
266 case RXRPC_PACKET_TYPE_11:
267 return just_discard;
268
269 default:
270 return rxrpc_bad_message(skb, rxrpc_badmsg_unsupported_packet);
271 }
272
273 if (sp->hdr.serviceId == 0)
274 return rxrpc_bad_message(skb, rxrpc_badmsg_zero_service);
275
276 if (WARN_ON_ONCE(rxrpc_extract_addr_from_skb(&peer_srx, skb) < 0))
277 return just_discard; /* Unsupported address type. */
278
279 if (peer_srx.transport.family != local->srx.transport.family &&
280 (peer_srx.transport.family == AF_INET &&
281 local->srx.transport.family != AF_INET6)) {
282 pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
283 peer_srx.transport.family,
284 local->srx.transport.family);
285 return just_discard; /* Wrong address type. */
286 }
287
288 if (rxrpc_to_client(sp)) {
289 rcu_read_lock();
290 conn = rxrpc_find_client_connection_rcu(local, &peer_srx, skb);
291 conn = rxrpc_get_connection_maybe(conn, rxrpc_conn_get_call_input);
292 rcu_read_unlock();
293 if (!conn)
294 return rxrpc_protocol_error(skb, rxrpc_eproto_no_client_conn);
295
296 ret = rxrpc_input_packet_on_conn(conn, &peer_srx, skb);
297 rxrpc_put_connection(conn, rxrpc_conn_put_call_input);
298 return ret;
299 }
300
301 /* We need to look up service connections by the full protocol
302 * parameter set. We look up the peer first as an intermediate step
303 * and then the connection from the peer's tree.
304 */
305 rcu_read_lock();
306
307 peer = rxrpc_lookup_peer_rcu(local, &peer_srx);
308 if (!peer) {
309 rcu_read_unlock();
310 return rxrpc_new_incoming_call(local, NULL, NULL, &peer_srx, skb);
311 }
312
313 conn = rxrpc_find_service_conn_rcu(peer, skb);
314 conn = rxrpc_get_connection_maybe(conn, rxrpc_conn_get_call_input);
315 if (conn) {
316 rcu_read_unlock();
317 ret = rxrpc_input_packet_on_conn(conn, &peer_srx, skb);
318 rxrpc_put_connection(conn, rxrpc_conn_put_call_input);
319 return ret;
320 }
321
322 peer = rxrpc_get_peer_maybe(peer, rxrpc_peer_get_input);
323 rcu_read_unlock();
324
325 ret = rxrpc_new_incoming_call(local, peer, NULL, &peer_srx, skb);
326 rxrpc_put_peer(peer, rxrpc_peer_put_input);
327 return ret;
328 }
329
330 /*
331 * Deal with a packet that's associated with an extant connection.
332 */
rxrpc_input_packet_on_conn(struct rxrpc_connection * conn,struct sockaddr_rxrpc * peer_srx,struct sk_buff * skb)333 static int rxrpc_input_packet_on_conn(struct rxrpc_connection *conn,
334 struct sockaddr_rxrpc *peer_srx,
335 struct sk_buff *skb)
336 {
337 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
338 struct rxrpc_channel *chan;
339 struct rxrpc_call *call = NULL;
340 unsigned int channel;
341
342 if (sp->hdr.securityIndex != conn->security_ix)
343 return rxrpc_direct_abort(skb, rxrpc_eproto_wrong_security,
344 RXKADINCONSISTENCY, -EBADMSG);
345
346 if (sp->hdr.serviceId != conn->service_id) {
347 int old_id;
348
349 if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags))
350 return rxrpc_protocol_error(skb, rxrpc_eproto_reupgrade);
351
352 old_id = cmpxchg(&conn->service_id, conn->orig_service_id,
353 sp->hdr.serviceId);
354 if (old_id != conn->orig_service_id &&
355 old_id != sp->hdr.serviceId)
356 return rxrpc_protocol_error(skb, rxrpc_eproto_bad_upgrade);
357 }
358
359 if (after(sp->hdr.serial, conn->hi_serial))
360 conn->hi_serial = sp->hdr.serial;
361
362 /* It's a connection-level packet if the call number is 0. */
363 if (sp->hdr.callNumber == 0)
364 return rxrpc_input_conn_packet(conn, skb);
365
366 /* Deal with path MTU discovery probing. */
367 if (sp->hdr.type == RXRPC_PACKET_TYPE_ACK &&
368 conn->pmtud_probe &&
369 after_eq(sp->ack.acked_serial, conn->pmtud_probe))
370 rxrpc_input_probe_for_pmtud(conn, sp->ack.acked_serial, false);
371
372 /* Call-bound packets are routed by connection channel. */
373 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
374 chan = &conn->channels[channel];
375
376 /* Ignore really old calls */
377 if (sp->hdr.callNumber < chan->last_call)
378 return just_discard;
379
380 if (sp->hdr.callNumber == chan->last_call) {
381 if (chan->call ||
382 sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)
383 return just_discard;
384
385 /* For the previous service call, if completed successfully, we
386 * discard all further packets.
387 */
388 if (rxrpc_conn_is_service(conn) &&
389 chan->last_type == RXRPC_PACKET_TYPE_ACK)
390 return just_discard;
391
392 /* But otherwise we need to retransmit the final packet from
393 * data cached in the connection record.
394 */
395 if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
396 trace_rxrpc_rx_data(chan->call_debug_id,
397 sp->hdr.seq,
398 sp->hdr.serial,
399 sp->hdr.flags);
400 rxrpc_conn_retransmit_call(conn, skb, channel);
401 return just_discard;
402 }
403
404 call = rxrpc_try_get_call(chan->call, rxrpc_call_get_input);
405
406 if (sp->hdr.callNumber > chan->call_id) {
407 if (rxrpc_to_client(sp)) {
408 rxrpc_put_call(call, rxrpc_call_put_input);
409 return rxrpc_protocol_error(skb,
410 rxrpc_eproto_unexpected_implicit_end);
411 }
412
413 if (call) {
414 rxrpc_implicit_end_call(call, skb);
415 rxrpc_put_call(call, rxrpc_call_put_input);
416 call = NULL;
417 }
418 }
419
420 if (!call) {
421 if (rxrpc_to_client(sp))
422 return rxrpc_protocol_error(skb, rxrpc_eproto_no_client_call);
423 return rxrpc_new_incoming_call(conn->local, conn->peer, conn,
424 peer_srx, skb);
425 }
426
427 rxrpc_queue_rx_call_packet(call, skb);
428 rxrpc_put_call(call, rxrpc_call_put_input);
429 return true;
430 }
431
432 /*
433 * I/O and event handling thread.
434 */
rxrpc_io_thread(void * data)435 int rxrpc_io_thread(void *data)
436 {
437 struct rxrpc_connection *conn;
438 struct sk_buff_head rx_queue;
439 struct rxrpc_local *local = data;
440 struct rxrpc_call *call;
441 struct sk_buff *skb;
442 #ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
443 ktime_t now;
444 #endif
445 bool should_stop;
446 LIST_HEAD(conn_attend_q);
447 LIST_HEAD(call_attend_q);
448
449 complete(&local->io_thread_ready);
450
451 skb_queue_head_init(&rx_queue);
452
453 set_user_nice(current, MIN_NICE);
454
455 for (;;) {
456 rxrpc_inc_stat(local->rxnet, stat_io_loop);
457
458 /* Inject a delay into packets if requested. */
459 #ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
460 now = ktime_get_real();
461 while ((skb = skb_peek(&local->rx_delay_queue))) {
462 if (ktime_before(now, skb->tstamp))
463 break;
464 skb = skb_dequeue(&local->rx_delay_queue);
465 skb_queue_tail(&local->rx_queue, skb);
466 }
467 #endif
468
469 if (!skb_queue_empty(&local->rx_queue)) {
470 spin_lock_irq(&local->rx_queue.lock);
471 skb_queue_splice_tail_init(&local->rx_queue, &rx_queue);
472 spin_unlock_irq(&local->rx_queue.lock);
473 trace_rxrpc_iothread_rx(local, skb_queue_len(&rx_queue));
474 }
475
476 /* Distribute packets and errors. */
477 while ((skb = __skb_dequeue(&rx_queue))) {
478 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
479 switch (skb->mark) {
480 case RXRPC_SKB_MARK_PACKET:
481 skb->priority = 0;
482 if (!rxrpc_input_packet(local, &skb))
483 rxrpc_reject_packet(local, skb);
484 trace_rxrpc_rx_done(skb->mark, skb->priority);
485 rxrpc_free_skb(skb, rxrpc_skb_put_input);
486 break;
487 case RXRPC_SKB_MARK_ERROR:
488 rxrpc_input_error(local, skb);
489 rxrpc_free_skb(skb, rxrpc_skb_put_error_report);
490 break;
491 case RXRPC_SKB_MARK_SERVICE_CONN_SECURED:
492 rxrpc_input_conn_event(sp->conn, skb);
493 rxrpc_put_connection(sp->conn, rxrpc_conn_put_poke);
494 rxrpc_free_skb(skb, rxrpc_skb_put_conn_secured);
495 break;
496 default:
497 WARN_ON_ONCE(1);
498 rxrpc_free_skb(skb, rxrpc_skb_put_unknown);
499 break;
500 }
501 }
502
503 /* Deal with connections that want immediate attention. */
504 spin_lock_irq(&local->lock);
505 list_splice_tail_init(&local->conn_attend_q, &conn_attend_q);
506 spin_unlock_irq(&local->lock);
507
508 while ((conn = list_first_entry_or_null(&conn_attend_q,
509 struct rxrpc_connection,
510 attend_link))) {
511 spin_lock_irq(&local->lock);
512 list_del_init(&conn->attend_link);
513 spin_unlock_irq(&local->lock);
514 rxrpc_input_conn_event(conn, NULL);
515 rxrpc_put_connection(conn, rxrpc_conn_put_poke);
516 }
517
518 if (test_and_clear_bit(RXRPC_CLIENT_CONN_REAP_TIMER,
519 &local->client_conn_flags))
520 rxrpc_discard_expired_client_conns(local);
521
522 /* Deal with calls that want immediate attention. */
523 spin_lock_irq(&local->lock);
524 list_splice_tail_init(&local->call_attend_q, &call_attend_q);
525 spin_unlock_irq(&local->lock);
526
527 while ((call = list_first_entry_or_null(&call_attend_q,
528 struct rxrpc_call,
529 attend_link))) {
530 spin_lock_irq(&local->lock);
531 list_del_init(&call->attend_link);
532 spin_unlock_irq(&local->lock);
533 trace_rxrpc_call_poked(call);
534 rxrpc_input_call_event(call);
535 rxrpc_put_call(call, rxrpc_call_put_poke);
536 }
537
538 if (!list_empty(&local->new_client_calls))
539 rxrpc_connect_client_calls(local);
540
541 set_current_state(TASK_INTERRUPTIBLE);
542 should_stop = kthread_should_stop();
543 if (!skb_queue_empty(&local->rx_queue) ||
544 !list_empty(&local->call_attend_q) ||
545 !list_empty(&local->conn_attend_q) ||
546 !list_empty(&local->new_client_calls) ||
547 test_bit(RXRPC_CLIENT_CONN_REAP_TIMER,
548 &local->client_conn_flags)) {
549 __set_current_state(TASK_RUNNING);
550 continue;
551 }
552
553 if (should_stop)
554 break;
555
556 #ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
557 skb = skb_peek(&local->rx_delay_queue);
558 if (skb) {
559 unsigned long timeout;
560 ktime_t tstamp = skb->tstamp;
561 ktime_t now = ktime_get_real();
562 s64 delay_ns = ktime_to_ns(ktime_sub(tstamp, now));
563
564 if (delay_ns <= 0) {
565 __set_current_state(TASK_RUNNING);
566 continue;
567 }
568
569 timeout = nsecs_to_jiffies(delay_ns);
570 timeout = umax(timeout, 1);
571 schedule_timeout(timeout);
572 __set_current_state(TASK_RUNNING);
573 continue;
574 }
575 #endif
576
577 schedule();
578 }
579
580 __set_current_state(TASK_RUNNING);
581 rxrpc_see_local(local, rxrpc_local_stop);
582 rxrpc_destroy_local(local);
583 WRITE_ONCE(local->io_thread, NULL);
584 rxrpc_see_local(local, rxrpc_local_stopped);
585 return 0;
586 }
587