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 (dhowells@redhat.com)
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
100 /*
101 * Directly produce a connection abort from a packet.
102 */
rxrpc_direct_conn_abort(struct sk_buff * skb,enum rxrpc_abort_reason why,s32 abort_code,int err)103 bool rxrpc_direct_conn_abort(struct sk_buff *skb, enum rxrpc_abort_reason why,
104 s32 abort_code, int err)
105 {
106 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
107
108 trace_rxrpc_abort(0, why, sp->hdr.cid, 0, sp->hdr.seq, abort_code, err);
109 skb->mark = RXRPC_SKB_MARK_REJECT_CONN_ABORT;
110 skb->priority = abort_code;
111 return false;
112 }
113
rxrpc_bad_message(struct sk_buff * skb,enum rxrpc_abort_reason why)114 static bool rxrpc_bad_message(struct sk_buff *skb, enum rxrpc_abort_reason why)
115 {
116 return rxrpc_direct_abort(skb, why, RX_PROTOCOL_ERROR, -EBADMSG);
117 }
118
119 #define just_discard true
120
121 /*
122 * Process event packets targeted at a local endpoint.
123 */
rxrpc_input_version(struct rxrpc_local * local,struct sk_buff * skb)124 static bool rxrpc_input_version(struct rxrpc_local *local, struct sk_buff *skb)
125 {
126 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
127 char v;
128
129 _enter("");
130
131 rxrpc_see_skb(skb, rxrpc_skb_see_version);
132 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header), &v, 1) >= 0) {
133 if (v == 0)
134 rxrpc_send_version_request(local, &sp->hdr, skb);
135 }
136
137 return true;
138 }
139
140 /*
141 * Extract the wire header from a packet and translate the byte order.
142 */
rxrpc_extract_header(struct rxrpc_skb_priv * sp,struct sk_buff * skb)143 static bool rxrpc_extract_header(struct rxrpc_skb_priv *sp,
144 struct sk_buff *skb)
145 {
146 struct rxrpc_wire_header whdr;
147 struct rxrpc_ackpacket ack;
148
149 /* dig out the RxRPC connection details */
150 if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
151 return rxrpc_bad_message(skb, rxrpc_badmsg_short_hdr);
152
153 memset(sp, 0, sizeof(*sp));
154 sp->hdr.epoch = ntohl(whdr.epoch);
155 sp->hdr.cid = ntohl(whdr.cid);
156 sp->hdr.callNumber = ntohl(whdr.callNumber);
157 sp->hdr.seq = ntohl(whdr.seq);
158 sp->hdr.serial = ntohl(whdr.serial);
159 sp->hdr.flags = whdr.flags;
160 sp->hdr.type = whdr.type;
161 sp->hdr.userStatus = whdr.userStatus;
162 sp->hdr.securityIndex = whdr.securityIndex;
163 sp->hdr._rsvd = ntohs(whdr._rsvd);
164 sp->hdr.serviceId = ntohs(whdr.serviceId);
165
166 if (sp->hdr.type == RXRPC_PACKET_TYPE_ACK) {
167 if (skb_copy_bits(skb, sizeof(whdr), &ack, sizeof(ack)) < 0)
168 return rxrpc_bad_message(skb, rxrpc_badmsg_short_ack);
169 sp->ack.first_ack = ntohl(ack.firstPacket);
170 sp->ack.prev_ack = ntohl(ack.previousPacket);
171 sp->ack.acked_serial = ntohl(ack.serial);
172 sp->ack.reason = ack.reason;
173 sp->ack.nr_acks = ack.nAcks;
174 }
175 return true;
176 }
177
178 /*
179 * Extract the abort code from an ABORT packet and stash it in skb->priority.
180 */
rxrpc_extract_abort(struct sk_buff * skb)181 static bool rxrpc_extract_abort(struct sk_buff *skb)
182 {
183 __be32 wtmp;
184
185 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
186 &wtmp, sizeof(wtmp)) < 0)
187 return false;
188 skb->priority = ntohl(wtmp);
189 return true;
190 }
191
192 /*
193 * Process packets received on the local endpoint
194 */
rxrpc_input_packet(struct rxrpc_local * local,struct sk_buff ** _skb)195 static bool rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff **_skb)
196 {
197 struct rxrpc_connection *conn;
198 struct sockaddr_rxrpc peer_srx;
199 struct rxrpc_skb_priv *sp;
200 struct rxrpc_peer *peer = NULL;
201 struct sk_buff *skb = *_skb;
202 bool ret = false;
203
204 skb_pull(skb, sizeof(struct udphdr));
205
206 sp = rxrpc_skb(skb);
207
208 /* dig out the RxRPC connection details */
209 if (!rxrpc_extract_header(sp, skb))
210 return just_discard;
211
212 if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
213 static int lose;
214 if ((lose++ & 7) == 7) {
215 trace_rxrpc_rx_lose(sp);
216 return just_discard;
217 }
218 }
219
220 trace_rxrpc_rx_packet(sp);
221
222 switch (sp->hdr.type) {
223 case RXRPC_PACKET_TYPE_VERSION:
224 if (rxrpc_to_client(sp))
225 return just_discard;
226 return rxrpc_input_version(local, skb);
227
228 case RXRPC_PACKET_TYPE_BUSY:
229 if (rxrpc_to_server(sp))
230 return just_discard;
231 fallthrough;
232 case RXRPC_PACKET_TYPE_ACK:
233 case RXRPC_PACKET_TYPE_ACKALL:
234 if (sp->hdr.callNumber == 0)
235 return rxrpc_bad_message(skb, rxrpc_badmsg_zero_call);
236 break;
237 case RXRPC_PACKET_TYPE_ABORT:
238 if (!rxrpc_extract_abort(skb))
239 return just_discard; /* Just discard if malformed */
240 break;
241
242 case RXRPC_PACKET_TYPE_DATA:
243 if (sp->hdr.callNumber == 0)
244 return rxrpc_bad_message(skb, rxrpc_badmsg_zero_call);
245 if (sp->hdr.seq == 0)
246 return rxrpc_bad_message(skb, rxrpc_badmsg_zero_seq);
247
248 /* Unshare the packet so that it can be modified for in-place
249 * decryption.
250 */
251 if (sp->hdr.securityIndex != 0) {
252 skb = skb_unshare(skb, GFP_ATOMIC);
253 if (!skb) {
254 rxrpc_eaten_skb(*_skb, rxrpc_skb_eaten_by_unshare_nomem);
255 *_skb = NULL;
256 return just_discard;
257 }
258
259 if (skb != *_skb) {
260 rxrpc_eaten_skb(*_skb, rxrpc_skb_eaten_by_unshare);
261 *_skb = skb;
262 rxrpc_new_skb(skb, rxrpc_skb_new_unshared);
263 sp = rxrpc_skb(skb);
264 }
265 }
266 break;
267
268 case RXRPC_PACKET_TYPE_CHALLENGE:
269 if (rxrpc_to_server(sp))
270 return just_discard;
271 break;
272 case RXRPC_PACKET_TYPE_RESPONSE:
273 if (rxrpc_to_client(sp))
274 return just_discard;
275 break;
276
277 /* Packet types 9-11 should just be ignored. */
278 case RXRPC_PACKET_TYPE_PARAMS:
279 case RXRPC_PACKET_TYPE_10:
280 case RXRPC_PACKET_TYPE_11:
281 return just_discard;
282
283 default:
284 return rxrpc_bad_message(skb, rxrpc_badmsg_unsupported_packet);
285 }
286
287 if (sp->hdr.serviceId == 0)
288 return rxrpc_bad_message(skb, rxrpc_badmsg_zero_service);
289
290 if (WARN_ON_ONCE(rxrpc_extract_addr_from_skb(&peer_srx, skb) < 0))
291 return just_discard; /* Unsupported address type. */
292
293 if (peer_srx.transport.family != local->srx.transport.family &&
294 (peer_srx.transport.family == AF_INET &&
295 local->srx.transport.family != AF_INET6)) {
296 pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
297 peer_srx.transport.family,
298 local->srx.transport.family);
299 return just_discard; /* Wrong address type. */
300 }
301
302 if (rxrpc_to_client(sp)) {
303 rcu_read_lock();
304 conn = rxrpc_find_client_connection_rcu(local, &peer_srx, skb);
305 conn = rxrpc_get_connection_maybe(conn, rxrpc_conn_get_call_input);
306 rcu_read_unlock();
307 if (!conn)
308 return rxrpc_protocol_error(skb, rxrpc_eproto_no_client_conn);
309
310 ret = rxrpc_input_packet_on_conn(conn, &peer_srx, skb);
311 rxrpc_put_connection(conn, rxrpc_conn_put_call_input);
312 return ret;
313 }
314
315 /* We need to look up service connections by the full protocol
316 * parameter set. We look up the peer first as an intermediate step
317 * and then the connection from the peer's tree.
318 */
319 rcu_read_lock();
320
321 peer = rxrpc_lookup_peer_rcu(local, &peer_srx);
322 if (!peer) {
323 rcu_read_unlock();
324 return rxrpc_new_incoming_call(local, NULL, NULL, &peer_srx, skb);
325 }
326
327 conn = rxrpc_find_service_conn_rcu(peer, skb);
328 conn = rxrpc_get_connection_maybe(conn, rxrpc_conn_get_call_input);
329 if (conn) {
330 rcu_read_unlock();
331 ret = rxrpc_input_packet_on_conn(conn, &peer_srx, skb);
332 rxrpc_put_connection(conn, rxrpc_conn_put_call_input);
333 return ret;
334 }
335
336 peer = rxrpc_get_peer_maybe(peer, rxrpc_peer_get_input);
337 rcu_read_unlock();
338
339 ret = rxrpc_new_incoming_call(local, peer, NULL, &peer_srx, skb);
340 rxrpc_put_peer(peer, rxrpc_peer_put_input);
341 return ret;
342 }
343
344 /*
345 * Deal with a packet that's associated with an extant connection.
346 */
rxrpc_input_packet_on_conn(struct rxrpc_connection * conn,struct sockaddr_rxrpc * peer_srx,struct sk_buff * skb)347 static int rxrpc_input_packet_on_conn(struct rxrpc_connection *conn,
348 struct sockaddr_rxrpc *peer_srx,
349 struct sk_buff *skb)
350 {
351 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
352 struct rxrpc_channel *chan;
353 struct rxrpc_call *call = NULL;
354 unsigned int channel;
355
356 if (sp->hdr.securityIndex != conn->security_ix)
357 return rxrpc_direct_abort(skb, rxrpc_eproto_wrong_security,
358 RXKADINCONSISTENCY, -EBADMSG);
359
360 if (sp->hdr.serviceId != conn->service_id) {
361 int old_id;
362
363 if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags))
364 return rxrpc_protocol_error(skb, rxrpc_eproto_reupgrade);
365
366 old_id = cmpxchg(&conn->service_id, conn->orig_service_id,
367 sp->hdr.serviceId);
368 if (old_id != conn->orig_service_id &&
369 old_id != sp->hdr.serviceId)
370 return rxrpc_protocol_error(skb, rxrpc_eproto_bad_upgrade);
371 }
372
373 if (after(sp->hdr.serial, conn->hi_serial))
374 conn->hi_serial = sp->hdr.serial;
375
376 /* It's a connection-level packet if the call number is 0. */
377 if (sp->hdr.callNumber == 0)
378 return rxrpc_input_conn_packet(conn, skb);
379
380 /* Deal with path MTU discovery probing. */
381 if (sp->hdr.type == RXRPC_PACKET_TYPE_ACK &&
382 conn->pmtud_probe &&
383 after_eq(sp->ack.acked_serial, conn->pmtud_probe))
384 rxrpc_input_probe_for_pmtud(conn, sp->ack.acked_serial, false);
385
386 /* Call-bound packets are routed by connection channel. */
387 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
388 chan = &conn->channels[channel];
389
390 /* Ignore really old calls */
391 if (sp->hdr.callNumber < chan->last_call)
392 return just_discard;
393
394 if (sp->hdr.callNumber == chan->last_call) {
395 if (chan->call ||
396 sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)
397 return just_discard;
398
399 /* For the previous service call, if completed successfully, we
400 * discard all further packets.
401 */
402 if (rxrpc_conn_is_service(conn) &&
403 chan->last_type == RXRPC_PACKET_TYPE_ACK)
404 return just_discard;
405
406 /* But otherwise we need to retransmit the final packet from
407 * data cached in the connection record.
408 */
409 if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
410 trace_rxrpc_rx_data(chan->call_debug_id,
411 sp->hdr.seq,
412 sp->hdr.serial,
413 sp->hdr.flags);
414 rxrpc_conn_retransmit_call(conn, skb, channel);
415 return just_discard;
416 }
417
418 call = rxrpc_try_get_call(chan->call, rxrpc_call_get_input);
419
420 if (sp->hdr.callNumber > chan->call_id) {
421 if (rxrpc_to_client(sp)) {
422 rxrpc_put_call(call, rxrpc_call_put_input);
423 return rxrpc_protocol_error(skb,
424 rxrpc_eproto_unexpected_implicit_end);
425 }
426
427 if (call) {
428 rxrpc_implicit_end_call(call, skb);
429 rxrpc_put_call(call, rxrpc_call_put_input);
430 call = NULL;
431 }
432 }
433
434 if (!call) {
435 if (rxrpc_to_client(sp))
436 return rxrpc_protocol_error(skb, rxrpc_eproto_no_client_call);
437 return rxrpc_new_incoming_call(conn->local, conn->peer, conn,
438 peer_srx, skb);
439 }
440
441 rxrpc_queue_rx_call_packet(call, skb);
442 rxrpc_put_call(call, rxrpc_call_put_input);
443 return true;
444 }
445
446 /*
447 * I/O and event handling thread.
448 */
rxrpc_io_thread(void * data)449 int rxrpc_io_thread(void *data)
450 {
451 struct rxrpc_connection *conn;
452 struct sk_buff_head rx_queue;
453 struct rxrpc_local *local = data;
454 struct rxrpc_call *call;
455 struct sk_buff *skb;
456 #ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
457 ktime_t now;
458 #endif
459 bool should_stop;
460 LIST_HEAD(conn_attend_q);
461 LIST_HEAD(call_attend_q);
462
463 complete(&local->io_thread_ready);
464
465 skb_queue_head_init(&rx_queue);
466
467 set_user_nice(current, MIN_NICE);
468
469 for (;;) {
470 rxrpc_inc_stat(local->rxnet, stat_io_loop);
471
472 /* Inject a delay into packets if requested. */
473 #ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
474 now = ktime_get_real();
475 while ((skb = skb_peek(&local->rx_delay_queue))) {
476 if (ktime_before(now, skb->tstamp))
477 break;
478 skb = skb_dequeue(&local->rx_delay_queue);
479 skb_queue_tail(&local->rx_queue, skb);
480 }
481 #endif
482
483 if (!skb_queue_empty(&local->rx_queue)) {
484 spin_lock_irq(&local->rx_queue.lock);
485 skb_queue_splice_tail_init(&local->rx_queue, &rx_queue);
486 spin_unlock_irq(&local->rx_queue.lock);
487 trace_rxrpc_iothread_rx(local, skb_queue_len(&rx_queue));
488 }
489
490 /* Distribute packets and errors. */
491 while ((skb = __skb_dequeue(&rx_queue))) {
492 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
493 switch (skb->mark) {
494 case RXRPC_SKB_MARK_PACKET:
495 skb->priority = 0;
496 if (!rxrpc_input_packet(local, &skb))
497 rxrpc_reject_packet(local, skb);
498 trace_rxrpc_rx_done(skb->mark, skb->priority);
499 rxrpc_free_skb(skb, rxrpc_skb_put_input);
500 break;
501 case RXRPC_SKB_MARK_ERROR:
502 rxrpc_input_error(local, skb);
503 rxrpc_free_skb(skb, rxrpc_skb_put_error_report);
504 break;
505 case RXRPC_SKB_MARK_SERVICE_CONN_SECURED:
506 rxrpc_input_conn_event(sp->poke_conn, skb);
507 rxrpc_put_connection(sp->poke_conn, rxrpc_conn_put_poke);
508 rxrpc_free_skb(skb, rxrpc_skb_put_conn_secured);
509 break;
510 default:
511 WARN_ON_ONCE(1);
512 rxrpc_free_skb(skb, rxrpc_skb_put_unknown);
513 break;
514 }
515 }
516
517 /* Deal with connections that want immediate attention. */
518 if (!list_empty_careful(&local->conn_attend_q)) {
519 spin_lock_irq(&local->lock);
520 list_splice_tail_init(&local->conn_attend_q, &conn_attend_q);
521 spin_unlock_irq(&local->lock);
522 }
523
524 while ((conn = list_first_entry_or_null(&conn_attend_q,
525 struct rxrpc_connection,
526 attend_link))) {
527 spin_lock_irq(&local->lock);
528 list_del_init(&conn->attend_link);
529 spin_unlock_irq(&local->lock);
530 rxrpc_input_conn_event(conn, NULL);
531 rxrpc_put_connection(conn, rxrpc_conn_put_poke);
532 }
533
534 if (test_and_clear_bit(RXRPC_CLIENT_CONN_REAP_TIMER,
535 &local->client_conn_flags))
536 rxrpc_discard_expired_client_conns(local);
537
538 /* Deal with calls that want immediate attention. */
539 spin_lock_irq(&local->lock);
540 list_splice_tail_init(&local->call_attend_q, &call_attend_q);
541 spin_unlock_irq(&local->lock);
542
543 while ((call = list_first_entry_or_null(&call_attend_q,
544 struct rxrpc_call,
545 attend_link))) {
546 spin_lock_irq(&local->lock);
547 list_del_init(&call->attend_link);
548 spin_unlock_irq(&local->lock);
549 trace_rxrpc_call_poked(call);
550 rxrpc_input_call_event(call);
551 rxrpc_put_call(call, rxrpc_call_put_poke);
552 }
553
554 if (!list_empty(&local->new_client_calls))
555 rxrpc_connect_client_calls(local);
556
557 set_current_state(TASK_INTERRUPTIBLE);
558 should_stop = kthread_should_stop();
559 if (!skb_queue_empty(&local->rx_queue) ||
560 !list_empty(&local->call_attend_q) ||
561 !list_empty(&local->conn_attend_q) ||
562 !list_empty(&local->new_client_calls) ||
563 test_bit(RXRPC_CLIENT_CONN_REAP_TIMER,
564 &local->client_conn_flags)) {
565 __set_current_state(TASK_RUNNING);
566 continue;
567 }
568
569 if (should_stop)
570 break;
571
572 #ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
573 skb = skb_peek(&local->rx_delay_queue);
574 if (skb) {
575 unsigned long timeout;
576 ktime_t tstamp = skb->tstamp;
577 ktime_t now = ktime_get_real();
578 s64 delay_ns = ktime_to_ns(ktime_sub(tstamp, now));
579
580 if (delay_ns <= 0) {
581 __set_current_state(TASK_RUNNING);
582 continue;
583 }
584
585 timeout = nsecs_to_jiffies(delay_ns);
586 timeout = umax(timeout, 1);
587 schedule_timeout(timeout);
588 __set_current_state(TASK_RUNNING);
589 continue;
590 }
591 #endif
592
593 schedule();
594 }
595
596 __set_current_state(TASK_RUNNING);
597 rxrpc_see_local(local, rxrpc_local_stop);
598 rxrpc_destroy_local(local);
599 WRITE_ONCE(local->io_thread, NULL);
600 rxrpc_see_local(local, rxrpc_local_stopped);
601 return 0;
602 }
603