1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Client connection-specific management code.
3 *
4 * Copyright (C) 2016, 2020 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 *
7 * Client connections need to be cached for a little while after they've made a
8 * call so as to handle retransmitted DATA packets in case the server didn't
9 * receive the final ACK or terminating ABORT we sent it.
10 *
11 * There are flags of relevance to the cache:
12 *
13 * (2) DONT_REUSE - The connection should be discarded as soon as possible and
14 * should not be reused. This is set when an exclusive connection is used
15 * or a call ID counter overflows.
16 *
17 * The caching state may only be changed if the cache lock is held.
18 *
19 * There are two idle client connection expiry durations. If the total number
20 * of connections is below the reap threshold, we use the normal duration; if
21 * it's above, we use the fast duration.
22 */
23
24 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25
26 #include <linux/slab.h>
27 #include <linux/idr.h>
28 #include <linux/timer.h>
29 #include <linux/sched/signal.h>
30
31 #include "ar-internal.h"
32
33 __read_mostly unsigned int rxrpc_reap_client_connections = 900;
34 __read_mostly unsigned long rxrpc_conn_idle_client_expiry = 2 * 60 * HZ;
35 __read_mostly unsigned long rxrpc_conn_idle_client_fast_expiry = 2 * HZ;
36
37 /*
38 * We use machine-unique IDs for our client connections.
39 */
40 DEFINE_IDR(rxrpc_client_conn_ids);
41 static DEFINE_SPINLOCK(rxrpc_conn_id_lock);
42
43 static void rxrpc_deactivate_bundle(struct rxrpc_bundle *bundle);
44
45 /*
46 * Get a connection ID and epoch for a client connection from the global pool.
47 * The connection struct pointer is then recorded in the idr radix tree. The
48 * epoch doesn't change until the client is rebooted (or, at least, unless the
49 * module is unloaded).
50 */
rxrpc_get_client_connection_id(struct rxrpc_connection * conn,gfp_t gfp)51 static int rxrpc_get_client_connection_id(struct rxrpc_connection *conn,
52 gfp_t gfp)
53 {
54 struct rxrpc_net *rxnet = conn->params.local->rxnet;
55 int id;
56
57 _enter("");
58
59 idr_preload(gfp);
60 spin_lock(&rxrpc_conn_id_lock);
61
62 id = idr_alloc_cyclic(&rxrpc_client_conn_ids, conn,
63 1, 0x40000000, GFP_NOWAIT);
64 if (id < 0)
65 goto error;
66
67 spin_unlock(&rxrpc_conn_id_lock);
68 idr_preload_end();
69
70 conn->proto.epoch = rxnet->epoch;
71 conn->proto.cid = id << RXRPC_CIDSHIFT;
72 set_bit(RXRPC_CONN_HAS_IDR, &conn->flags);
73 _leave(" [CID %x]", conn->proto.cid);
74 return 0;
75
76 error:
77 spin_unlock(&rxrpc_conn_id_lock);
78 idr_preload_end();
79 _leave(" = %d", id);
80 return id;
81 }
82
83 /*
84 * Release a connection ID for a client connection from the global pool.
85 */
rxrpc_put_client_connection_id(struct rxrpc_connection * conn)86 static void rxrpc_put_client_connection_id(struct rxrpc_connection *conn)
87 {
88 if (test_bit(RXRPC_CONN_HAS_IDR, &conn->flags)) {
89 spin_lock(&rxrpc_conn_id_lock);
90 idr_remove(&rxrpc_client_conn_ids,
91 conn->proto.cid >> RXRPC_CIDSHIFT);
92 spin_unlock(&rxrpc_conn_id_lock);
93 }
94 }
95
96 /*
97 * Destroy the client connection ID tree.
98 */
rxrpc_destroy_client_conn_ids(void)99 void rxrpc_destroy_client_conn_ids(void)
100 {
101 struct rxrpc_connection *conn;
102 int id;
103
104 if (!idr_is_empty(&rxrpc_client_conn_ids)) {
105 idr_for_each_entry(&rxrpc_client_conn_ids, conn, id) {
106 pr_err("AF_RXRPC: Leaked client conn %p {%d}\n",
107 conn, refcount_read(&conn->ref));
108 }
109 BUG();
110 }
111
112 idr_destroy(&rxrpc_client_conn_ids);
113 }
114
115 /*
116 * Allocate a connection bundle.
117 */
rxrpc_alloc_bundle(struct rxrpc_conn_parameters * cp,gfp_t gfp)118 static struct rxrpc_bundle *rxrpc_alloc_bundle(struct rxrpc_conn_parameters *cp,
119 gfp_t gfp)
120 {
121 struct rxrpc_bundle *bundle;
122
123 bundle = kzalloc(sizeof(*bundle), gfp);
124 if (bundle) {
125 bundle->params = *cp;
126 rxrpc_get_peer(bundle->params.peer);
127 refcount_set(&bundle->ref, 1);
128 atomic_set(&bundle->active, 1);
129 spin_lock_init(&bundle->channel_lock);
130 INIT_LIST_HEAD(&bundle->waiting_calls);
131 }
132 return bundle;
133 }
134
rxrpc_get_bundle(struct rxrpc_bundle * bundle)135 struct rxrpc_bundle *rxrpc_get_bundle(struct rxrpc_bundle *bundle)
136 {
137 refcount_inc(&bundle->ref);
138 return bundle;
139 }
140
rxrpc_free_bundle(struct rxrpc_bundle * bundle)141 static void rxrpc_free_bundle(struct rxrpc_bundle *bundle)
142 {
143 rxrpc_put_peer(bundle->params.peer);
144 kfree(bundle);
145 }
146
rxrpc_put_bundle(struct rxrpc_bundle * bundle)147 void rxrpc_put_bundle(struct rxrpc_bundle *bundle)
148 {
149 unsigned int d = bundle->debug_id;
150 bool dead;
151 int r;
152
153 dead = __refcount_dec_and_test(&bundle->ref, &r);
154
155 _debug("PUT B=%x %d", d, r - 1);
156 if (dead)
157 rxrpc_free_bundle(bundle);
158 }
159
160 /*
161 * Allocate a client connection.
162 */
163 static struct rxrpc_connection *
rxrpc_alloc_client_connection(struct rxrpc_bundle * bundle,gfp_t gfp)164 rxrpc_alloc_client_connection(struct rxrpc_bundle *bundle, gfp_t gfp)
165 {
166 struct rxrpc_connection *conn;
167 struct rxrpc_net *rxnet = bundle->params.local->rxnet;
168 int ret;
169
170 _enter("");
171
172 conn = rxrpc_alloc_connection(gfp);
173 if (!conn) {
174 _leave(" = -ENOMEM");
175 return ERR_PTR(-ENOMEM);
176 }
177
178 refcount_set(&conn->ref, 1);
179 conn->bundle = bundle;
180 conn->params = bundle->params;
181 conn->out_clientflag = RXRPC_CLIENT_INITIATED;
182 conn->state = RXRPC_CONN_CLIENT;
183 conn->service_id = conn->params.service_id;
184
185 ret = rxrpc_get_client_connection_id(conn, gfp);
186 if (ret < 0)
187 goto error_0;
188
189 ret = rxrpc_init_client_conn_security(conn);
190 if (ret < 0)
191 goto error_1;
192
193 atomic_inc(&rxnet->nr_conns);
194 write_lock(&rxnet->conn_lock);
195 list_add_tail(&conn->proc_link, &rxnet->conn_proc_list);
196 write_unlock(&rxnet->conn_lock);
197
198 rxrpc_get_bundle(bundle);
199 rxrpc_get_peer(conn->params.peer);
200 rxrpc_get_local(conn->params.local);
201 key_get(conn->params.key);
202
203 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_new_client,
204 refcount_read(&conn->ref),
205 __builtin_return_address(0));
206
207 atomic_inc(&rxnet->nr_client_conns);
208 trace_rxrpc_client(conn, -1, rxrpc_client_alloc);
209 _leave(" = %p", conn);
210 return conn;
211
212 error_1:
213 rxrpc_put_client_connection_id(conn);
214 error_0:
215 kfree(conn);
216 _leave(" = %d", ret);
217 return ERR_PTR(ret);
218 }
219
220 /*
221 * Determine if a connection may be reused.
222 */
rxrpc_may_reuse_conn(struct rxrpc_connection * conn)223 static bool rxrpc_may_reuse_conn(struct rxrpc_connection *conn)
224 {
225 struct rxrpc_net *rxnet;
226 int id_cursor, id, distance, limit;
227
228 if (!conn)
229 goto dont_reuse;
230
231 rxnet = conn->params.local->rxnet;
232 if (test_bit(RXRPC_CONN_DONT_REUSE, &conn->flags))
233 goto dont_reuse;
234
235 if (conn->state != RXRPC_CONN_CLIENT ||
236 conn->proto.epoch != rxnet->epoch)
237 goto mark_dont_reuse;
238
239 /* The IDR tree gets very expensive on memory if the connection IDs are
240 * widely scattered throughout the number space, so we shall want to
241 * kill off connections that, say, have an ID more than about four
242 * times the maximum number of client conns away from the current
243 * allocation point to try and keep the IDs concentrated.
244 */
245 id_cursor = idr_get_cursor(&rxrpc_client_conn_ids);
246 id = conn->proto.cid >> RXRPC_CIDSHIFT;
247 distance = id - id_cursor;
248 if (distance < 0)
249 distance = -distance;
250 limit = max_t(unsigned long, atomic_read(&rxnet->nr_conns) * 4, 1024);
251 if (distance > limit)
252 goto mark_dont_reuse;
253
254 return true;
255
256 mark_dont_reuse:
257 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
258 dont_reuse:
259 return false;
260 }
261
262 /*
263 * Look up the conn bundle that matches the connection parameters, adding it if
264 * it doesn't yet exist.
265 */
rxrpc_look_up_bundle(struct rxrpc_conn_parameters * cp,gfp_t gfp)266 static struct rxrpc_bundle *rxrpc_look_up_bundle(struct rxrpc_conn_parameters *cp,
267 gfp_t gfp)
268 {
269 static atomic_t rxrpc_bundle_id;
270 struct rxrpc_bundle *bundle, *candidate;
271 struct rxrpc_local *local = cp->local;
272 struct rb_node *p, **pp, *parent;
273 long diff;
274
275 _enter("{%px,%x,%u,%u}",
276 cp->peer, key_serial(cp->key), cp->security_level, cp->upgrade);
277
278 if (cp->exclusive)
279 return rxrpc_alloc_bundle(cp, gfp);
280
281 /* First, see if the bundle is already there. */
282 _debug("search 1");
283 spin_lock(&local->client_bundles_lock);
284 p = local->client_bundles.rb_node;
285 while (p) {
286 bundle = rb_entry(p, struct rxrpc_bundle, local_node);
287
288 #define cmp(X) ((long)bundle->params.X - (long)cp->X)
289 diff = (cmp(peer) ?:
290 cmp(key) ?:
291 cmp(security_level) ?:
292 cmp(upgrade));
293 #undef cmp
294 if (diff < 0)
295 p = p->rb_left;
296 else if (diff > 0)
297 p = p->rb_right;
298 else
299 goto found_bundle;
300 }
301 spin_unlock(&local->client_bundles_lock);
302 _debug("not found");
303
304 /* It wasn't. We need to add one. */
305 candidate = rxrpc_alloc_bundle(cp, gfp);
306 if (!candidate)
307 return NULL;
308
309 _debug("search 2");
310 spin_lock(&local->client_bundles_lock);
311 pp = &local->client_bundles.rb_node;
312 parent = NULL;
313 while (*pp) {
314 parent = *pp;
315 bundle = rb_entry(parent, struct rxrpc_bundle, local_node);
316
317 #define cmp(X) ((long)bundle->params.X - (long)cp->X)
318 diff = (cmp(peer) ?:
319 cmp(key) ?:
320 cmp(security_level) ?:
321 cmp(upgrade));
322 #undef cmp
323 if (diff < 0)
324 pp = &(*pp)->rb_left;
325 else if (diff > 0)
326 pp = &(*pp)->rb_right;
327 else
328 goto found_bundle_free;
329 }
330
331 _debug("new bundle");
332 candidate->debug_id = atomic_inc_return(&rxrpc_bundle_id);
333 rb_link_node(&candidate->local_node, parent, pp);
334 rb_insert_color(&candidate->local_node, &local->client_bundles);
335 rxrpc_get_bundle(candidate);
336 spin_unlock(&local->client_bundles_lock);
337 _leave(" = %u [new]", candidate->debug_id);
338 return candidate;
339
340 found_bundle_free:
341 rxrpc_free_bundle(candidate);
342 found_bundle:
343 rxrpc_get_bundle(bundle);
344 atomic_inc(&bundle->active);
345 spin_unlock(&local->client_bundles_lock);
346 _leave(" = %u [found]", bundle->debug_id);
347 return bundle;
348 }
349
350 /*
351 * Create or find a client bundle to use for a call.
352 *
353 * If we return with a connection, the call will be on its waiting list. It's
354 * left to the caller to assign a channel and wake up the call.
355 */
rxrpc_prep_call(struct rxrpc_sock * rx,struct rxrpc_call * call,struct rxrpc_conn_parameters * cp,struct sockaddr_rxrpc * srx,gfp_t gfp)356 static struct rxrpc_bundle *rxrpc_prep_call(struct rxrpc_sock *rx,
357 struct rxrpc_call *call,
358 struct rxrpc_conn_parameters *cp,
359 struct sockaddr_rxrpc *srx,
360 gfp_t gfp)
361 {
362 struct rxrpc_bundle *bundle;
363
364 _enter("{%d,%lx},", call->debug_id, call->user_call_ID);
365
366 cp->peer = rxrpc_lookup_peer(rx, cp->local, srx, gfp);
367 if (!cp->peer)
368 goto error;
369
370 call->cong_cwnd = cp->peer->cong_cwnd;
371 if (call->cong_cwnd >= call->cong_ssthresh)
372 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
373 else
374 call->cong_mode = RXRPC_CALL_SLOW_START;
375 if (cp->upgrade)
376 __set_bit(RXRPC_CALL_UPGRADE, &call->flags);
377
378 /* Find the client connection bundle. */
379 bundle = rxrpc_look_up_bundle(cp, gfp);
380 if (!bundle)
381 goto error;
382
383 /* Get this call queued. Someone else may activate it whilst we're
384 * lining up a new connection, but that's fine.
385 */
386 spin_lock(&bundle->channel_lock);
387 list_add_tail(&call->chan_wait_link, &bundle->waiting_calls);
388 spin_unlock(&bundle->channel_lock);
389
390 _leave(" = [B=%x]", bundle->debug_id);
391 return bundle;
392
393 error:
394 _leave(" = -ENOMEM");
395 return ERR_PTR(-ENOMEM);
396 }
397
398 /*
399 * Allocate a new connection and add it into a bundle.
400 */
rxrpc_add_conn_to_bundle(struct rxrpc_bundle * bundle,gfp_t gfp)401 static void rxrpc_add_conn_to_bundle(struct rxrpc_bundle *bundle, gfp_t gfp)
402 __releases(bundle->channel_lock)
403 {
404 struct rxrpc_connection *candidate = NULL, *old = NULL;
405 bool conflict;
406 int i;
407
408 _enter("");
409
410 conflict = bundle->alloc_conn;
411 if (!conflict)
412 bundle->alloc_conn = true;
413 spin_unlock(&bundle->channel_lock);
414 if (conflict) {
415 _leave(" [conf]");
416 return;
417 }
418
419 candidate = rxrpc_alloc_client_connection(bundle, gfp);
420
421 spin_lock(&bundle->channel_lock);
422 bundle->alloc_conn = false;
423
424 if (IS_ERR(candidate)) {
425 bundle->alloc_error = PTR_ERR(candidate);
426 spin_unlock(&bundle->channel_lock);
427 _leave(" [err %ld]", PTR_ERR(candidate));
428 return;
429 }
430
431 bundle->alloc_error = 0;
432
433 for (i = 0; i < ARRAY_SIZE(bundle->conns); i++) {
434 unsigned int shift = i * RXRPC_MAXCALLS;
435 int j;
436
437 old = bundle->conns[i];
438 if (!rxrpc_may_reuse_conn(old)) {
439 if (old)
440 trace_rxrpc_client(old, -1, rxrpc_client_replace);
441 candidate->bundle_shift = shift;
442 atomic_inc(&bundle->active);
443 bundle->conns[i] = candidate;
444 for (j = 0; j < RXRPC_MAXCALLS; j++)
445 set_bit(shift + j, &bundle->avail_chans);
446 candidate = NULL;
447 break;
448 }
449
450 old = NULL;
451 }
452
453 spin_unlock(&bundle->channel_lock);
454
455 if (candidate) {
456 _debug("discard C=%x", candidate->debug_id);
457 trace_rxrpc_client(candidate, -1, rxrpc_client_duplicate);
458 rxrpc_put_connection(candidate);
459 }
460
461 rxrpc_put_connection(old);
462 _leave("");
463 }
464
465 /*
466 * Add a connection to a bundle if there are no usable connections or we have
467 * connections waiting for extra capacity.
468 */
rxrpc_maybe_add_conn(struct rxrpc_bundle * bundle,gfp_t gfp)469 static void rxrpc_maybe_add_conn(struct rxrpc_bundle *bundle, gfp_t gfp)
470 {
471 struct rxrpc_call *call;
472 int i, usable;
473
474 _enter("");
475
476 spin_lock(&bundle->channel_lock);
477
478 /* See if there are any usable connections. */
479 usable = 0;
480 for (i = 0; i < ARRAY_SIZE(bundle->conns); i++)
481 if (rxrpc_may_reuse_conn(bundle->conns[i]))
482 usable++;
483
484 if (!usable && !list_empty(&bundle->waiting_calls)) {
485 call = list_first_entry(&bundle->waiting_calls,
486 struct rxrpc_call, chan_wait_link);
487 if (test_bit(RXRPC_CALL_UPGRADE, &call->flags))
488 bundle->try_upgrade = true;
489 }
490
491 if (!usable)
492 goto alloc_conn;
493
494 if (!bundle->avail_chans &&
495 !bundle->try_upgrade &&
496 !list_empty(&bundle->waiting_calls) &&
497 usable < ARRAY_SIZE(bundle->conns))
498 goto alloc_conn;
499
500 spin_unlock(&bundle->channel_lock);
501 _leave("");
502 return;
503
504 alloc_conn:
505 return rxrpc_add_conn_to_bundle(bundle, gfp);
506 }
507
508 /*
509 * Assign a channel to the call at the front of the queue and wake the call up.
510 * We don't increment the callNumber counter until this number has been exposed
511 * to the world.
512 */
rxrpc_activate_one_channel(struct rxrpc_connection * conn,unsigned int channel)513 static void rxrpc_activate_one_channel(struct rxrpc_connection *conn,
514 unsigned int channel)
515 {
516 struct rxrpc_channel *chan = &conn->channels[channel];
517 struct rxrpc_bundle *bundle = conn->bundle;
518 struct rxrpc_call *call = list_entry(bundle->waiting_calls.next,
519 struct rxrpc_call, chan_wait_link);
520 u32 call_id = chan->call_counter + 1;
521
522 _enter("C=%x,%u", conn->debug_id, channel);
523
524 trace_rxrpc_client(conn, channel, rxrpc_client_chan_activate);
525
526 /* Cancel the final ACK on the previous call if it hasn't been sent yet
527 * as the DATA packet will implicitly ACK it.
528 */
529 clear_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags);
530 clear_bit(conn->bundle_shift + channel, &bundle->avail_chans);
531
532 rxrpc_see_call(call);
533 list_del_init(&call->chan_wait_link);
534 call->peer = rxrpc_get_peer(conn->params.peer);
535 call->conn = rxrpc_get_connection(conn);
536 call->cid = conn->proto.cid | channel;
537 call->call_id = call_id;
538 call->security = conn->security;
539 call->security_ix = conn->security_ix;
540 call->service_id = conn->service_id;
541
542 trace_rxrpc_connect_call(call);
543 _net("CONNECT call %08x:%08x as call %d on conn %d",
544 call->cid, call->call_id, call->debug_id, conn->debug_id);
545
546 write_lock_bh(&call->state_lock);
547 call->state = RXRPC_CALL_CLIENT_SEND_REQUEST;
548 write_unlock_bh(&call->state_lock);
549
550 /* Paired with the read barrier in rxrpc_connect_call(). This orders
551 * cid and epoch in the connection wrt to call_id without the need to
552 * take the channel_lock.
553 *
554 * We provisionally assign a callNumber at this point, but we don't
555 * confirm it until the call is about to be exposed.
556 *
557 * TODO: Pair with a barrier in the data_ready handler when that looks
558 * at the call ID through a connection channel.
559 */
560 smp_wmb();
561
562 chan->call_id = call_id;
563 chan->call_debug_id = call->debug_id;
564 rcu_assign_pointer(chan->call, call);
565 wake_up(&call->waitq);
566 }
567
568 /*
569 * Remove a connection from the idle list if it's on it.
570 */
rxrpc_unidle_conn(struct rxrpc_bundle * bundle,struct rxrpc_connection * conn)571 static void rxrpc_unidle_conn(struct rxrpc_bundle *bundle, struct rxrpc_connection *conn)
572 {
573 struct rxrpc_net *rxnet = bundle->params.local->rxnet;
574 bool drop_ref;
575
576 if (!list_empty(&conn->cache_link)) {
577 drop_ref = false;
578 spin_lock(&rxnet->client_conn_cache_lock);
579 if (!list_empty(&conn->cache_link)) {
580 list_del_init(&conn->cache_link);
581 drop_ref = true;
582 }
583 spin_unlock(&rxnet->client_conn_cache_lock);
584 if (drop_ref)
585 rxrpc_put_connection(conn);
586 }
587 }
588
589 /*
590 * Assign channels and callNumbers to waiting calls with channel_lock
591 * held by caller.
592 */
rxrpc_activate_channels_locked(struct rxrpc_bundle * bundle)593 static void rxrpc_activate_channels_locked(struct rxrpc_bundle *bundle)
594 {
595 struct rxrpc_connection *conn;
596 unsigned long avail, mask;
597 unsigned int channel, slot;
598
599 if (bundle->try_upgrade)
600 mask = 1;
601 else
602 mask = ULONG_MAX;
603
604 while (!list_empty(&bundle->waiting_calls)) {
605 avail = bundle->avail_chans & mask;
606 if (!avail)
607 break;
608 channel = __ffs(avail);
609 clear_bit(channel, &bundle->avail_chans);
610
611 slot = channel / RXRPC_MAXCALLS;
612 conn = bundle->conns[slot];
613 if (!conn)
614 break;
615
616 if (bundle->try_upgrade)
617 set_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags);
618 rxrpc_unidle_conn(bundle, conn);
619
620 channel &= (RXRPC_MAXCALLS - 1);
621 conn->act_chans |= 1 << channel;
622 rxrpc_activate_one_channel(conn, channel);
623 }
624 }
625
626 /*
627 * Assign channels and callNumbers to waiting calls.
628 */
rxrpc_activate_channels(struct rxrpc_bundle * bundle)629 static void rxrpc_activate_channels(struct rxrpc_bundle *bundle)
630 {
631 _enter("B=%x", bundle->debug_id);
632
633 trace_rxrpc_client(NULL, -1, rxrpc_client_activate_chans);
634
635 if (!bundle->avail_chans)
636 return;
637
638 spin_lock(&bundle->channel_lock);
639 rxrpc_activate_channels_locked(bundle);
640 spin_unlock(&bundle->channel_lock);
641 _leave("");
642 }
643
644 /*
645 * Wait for a callNumber and a channel to be granted to a call.
646 */
rxrpc_wait_for_channel(struct rxrpc_bundle * bundle,struct rxrpc_call * call,gfp_t gfp)647 static int rxrpc_wait_for_channel(struct rxrpc_bundle *bundle,
648 struct rxrpc_call *call, gfp_t gfp)
649 {
650 DECLARE_WAITQUEUE(myself, current);
651 int ret = 0;
652
653 _enter("%d", call->debug_id);
654
655 if (!gfpflags_allow_blocking(gfp)) {
656 rxrpc_maybe_add_conn(bundle, gfp);
657 rxrpc_activate_channels(bundle);
658 ret = bundle->alloc_error ?: -EAGAIN;
659 goto out;
660 }
661
662 add_wait_queue_exclusive(&call->waitq, &myself);
663 for (;;) {
664 rxrpc_maybe_add_conn(bundle, gfp);
665 rxrpc_activate_channels(bundle);
666 ret = bundle->alloc_error;
667 if (ret < 0)
668 break;
669
670 switch (call->interruptibility) {
671 case RXRPC_INTERRUPTIBLE:
672 case RXRPC_PREINTERRUPTIBLE:
673 set_current_state(TASK_INTERRUPTIBLE);
674 break;
675 case RXRPC_UNINTERRUPTIBLE:
676 default:
677 set_current_state(TASK_UNINTERRUPTIBLE);
678 break;
679 }
680 if (READ_ONCE(call->state) != RXRPC_CALL_CLIENT_AWAIT_CONN)
681 break;
682 if ((call->interruptibility == RXRPC_INTERRUPTIBLE ||
683 call->interruptibility == RXRPC_PREINTERRUPTIBLE) &&
684 signal_pending(current)) {
685 ret = -ERESTARTSYS;
686 break;
687 }
688 schedule();
689 }
690 remove_wait_queue(&call->waitq, &myself);
691 __set_current_state(TASK_RUNNING);
692
693 out:
694 _leave(" = %d", ret);
695 return ret;
696 }
697
698 /*
699 * find a connection for a call
700 * - called in process context with IRQs enabled
701 */
rxrpc_connect_call(struct rxrpc_sock * rx,struct rxrpc_call * call,struct rxrpc_conn_parameters * cp,struct sockaddr_rxrpc * srx,gfp_t gfp)702 int rxrpc_connect_call(struct rxrpc_sock *rx,
703 struct rxrpc_call *call,
704 struct rxrpc_conn_parameters *cp,
705 struct sockaddr_rxrpc *srx,
706 gfp_t gfp)
707 {
708 struct rxrpc_bundle *bundle;
709 struct rxrpc_net *rxnet = cp->local->rxnet;
710 int ret = 0;
711
712 _enter("{%d,%lx},", call->debug_id, call->user_call_ID);
713
714 rxrpc_discard_expired_client_conns(&rxnet->client_conn_reaper);
715
716 bundle = rxrpc_prep_call(rx, call, cp, srx, gfp);
717 if (IS_ERR(bundle)) {
718 ret = PTR_ERR(bundle);
719 goto out;
720 }
721
722 if (call->state == RXRPC_CALL_CLIENT_AWAIT_CONN) {
723 ret = rxrpc_wait_for_channel(bundle, call, gfp);
724 if (ret < 0)
725 goto wait_failed;
726 }
727
728 granted_channel:
729 /* Paired with the write barrier in rxrpc_activate_one_channel(). */
730 smp_rmb();
731
732 out_put_bundle:
733 rxrpc_deactivate_bundle(bundle);
734 rxrpc_put_bundle(bundle);
735 out:
736 _leave(" = %d", ret);
737 return ret;
738
739 wait_failed:
740 spin_lock(&bundle->channel_lock);
741 list_del_init(&call->chan_wait_link);
742 spin_unlock(&bundle->channel_lock);
743
744 if (call->state != RXRPC_CALL_CLIENT_AWAIT_CONN) {
745 ret = 0;
746 goto granted_channel;
747 }
748
749 trace_rxrpc_client(call->conn, ret, rxrpc_client_chan_wait_failed);
750 rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR, 0, ret);
751 rxrpc_disconnect_client_call(bundle, call);
752 goto out_put_bundle;
753 }
754
755 /*
756 * Note that a call, and thus a connection, is about to be exposed to the
757 * world.
758 */
rxrpc_expose_client_call(struct rxrpc_call * call)759 void rxrpc_expose_client_call(struct rxrpc_call *call)
760 {
761 unsigned int channel = call->cid & RXRPC_CHANNELMASK;
762 struct rxrpc_connection *conn = call->conn;
763 struct rxrpc_channel *chan = &conn->channels[channel];
764
765 if (!test_and_set_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
766 /* Mark the call ID as being used. If the callNumber counter
767 * exceeds ~2 billion, we kill the connection after its
768 * outstanding calls have finished so that the counter doesn't
769 * wrap.
770 */
771 chan->call_counter++;
772 if (chan->call_counter >= INT_MAX)
773 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
774 trace_rxrpc_client(conn, channel, rxrpc_client_exposed);
775 }
776 }
777
778 /*
779 * Set the reap timer.
780 */
rxrpc_set_client_reap_timer(struct rxrpc_net * rxnet)781 static void rxrpc_set_client_reap_timer(struct rxrpc_net *rxnet)
782 {
783 if (!rxnet->kill_all_client_conns) {
784 unsigned long now = jiffies;
785 unsigned long reap_at = now + rxrpc_conn_idle_client_expiry;
786
787 if (rxnet->live)
788 timer_reduce(&rxnet->client_conn_reap_timer, reap_at);
789 }
790 }
791
792 /*
793 * Disconnect a client call.
794 */
rxrpc_disconnect_client_call(struct rxrpc_bundle * bundle,struct rxrpc_call * call)795 void rxrpc_disconnect_client_call(struct rxrpc_bundle *bundle, struct rxrpc_call *call)
796 {
797 struct rxrpc_connection *conn;
798 struct rxrpc_channel *chan = NULL;
799 struct rxrpc_net *rxnet = bundle->params.local->rxnet;
800 unsigned int channel;
801 bool may_reuse;
802 u32 cid;
803
804 _enter("c=%x", call->debug_id);
805
806 spin_lock(&bundle->channel_lock);
807 set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
808
809 /* Calls that have never actually been assigned a channel can simply be
810 * discarded.
811 */
812 conn = call->conn;
813 if (!conn) {
814 _debug("call is waiting");
815 ASSERTCMP(call->call_id, ==, 0);
816 ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags));
817 list_del_init(&call->chan_wait_link);
818 goto out;
819 }
820
821 cid = call->cid;
822 channel = cid & RXRPC_CHANNELMASK;
823 chan = &conn->channels[channel];
824 trace_rxrpc_client(conn, channel, rxrpc_client_chan_disconnect);
825
826 if (rcu_access_pointer(chan->call) != call) {
827 spin_unlock(&bundle->channel_lock);
828 BUG();
829 }
830
831 may_reuse = rxrpc_may_reuse_conn(conn);
832
833 /* If a client call was exposed to the world, we save the result for
834 * retransmission.
835 *
836 * We use a barrier here so that the call number and abort code can be
837 * read without needing to take a lock.
838 *
839 * TODO: Make the incoming packet handler check this and handle
840 * terminal retransmission without requiring access to the call.
841 */
842 if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
843 _debug("exposed %u,%u", call->call_id, call->abort_code);
844 __rxrpc_disconnect_call(conn, call);
845
846 if (test_and_clear_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags)) {
847 trace_rxrpc_client(conn, channel, rxrpc_client_to_active);
848 bundle->try_upgrade = false;
849 if (may_reuse)
850 rxrpc_activate_channels_locked(bundle);
851 }
852
853 }
854
855 /* See if we can pass the channel directly to another call. */
856 if (may_reuse && !list_empty(&bundle->waiting_calls)) {
857 trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass);
858 rxrpc_activate_one_channel(conn, channel);
859 goto out;
860 }
861
862 /* Schedule the final ACK to be transmitted in a short while so that it
863 * can be skipped if we find a follow-on call. The first DATA packet
864 * of the follow on call will implicitly ACK this call.
865 */
866 if (call->completion == RXRPC_CALL_SUCCEEDED &&
867 test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
868 unsigned long final_ack_at = jiffies + 2;
869
870 WRITE_ONCE(chan->final_ack_at, final_ack_at);
871 smp_wmb(); /* vs rxrpc_process_delayed_final_acks() */
872 set_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags);
873 rxrpc_reduce_conn_timer(conn, final_ack_at);
874 }
875
876 /* Deactivate the channel. */
877 rcu_assign_pointer(chan->call, NULL);
878 set_bit(conn->bundle_shift + channel, &conn->bundle->avail_chans);
879 conn->act_chans &= ~(1 << channel);
880
881 /* If no channels remain active, then put the connection on the idle
882 * list for a short while. Give it a ref to stop it going away if it
883 * becomes unbundled.
884 */
885 if (!conn->act_chans) {
886 trace_rxrpc_client(conn, channel, rxrpc_client_to_idle);
887 conn->idle_timestamp = jiffies;
888
889 rxrpc_get_connection(conn);
890 spin_lock(&rxnet->client_conn_cache_lock);
891 list_move_tail(&conn->cache_link, &rxnet->idle_client_conns);
892 spin_unlock(&rxnet->client_conn_cache_lock);
893
894 rxrpc_set_client_reap_timer(rxnet);
895 }
896
897 out:
898 spin_unlock(&bundle->channel_lock);
899 _leave("");
900 return;
901 }
902
903 /*
904 * Remove a connection from a bundle.
905 */
rxrpc_unbundle_conn(struct rxrpc_connection * conn)906 static void rxrpc_unbundle_conn(struct rxrpc_connection *conn)
907 {
908 struct rxrpc_bundle *bundle = conn->bundle;
909 unsigned int bindex;
910 bool need_drop = false;
911 int i;
912
913 _enter("C=%x", conn->debug_id);
914
915 if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
916 rxrpc_process_delayed_final_acks(conn, true);
917
918 spin_lock(&bundle->channel_lock);
919 bindex = conn->bundle_shift / RXRPC_MAXCALLS;
920 if (bundle->conns[bindex] == conn) {
921 _debug("clear slot %u", bindex);
922 bundle->conns[bindex] = NULL;
923 for (i = 0; i < RXRPC_MAXCALLS; i++)
924 clear_bit(conn->bundle_shift + i, &bundle->avail_chans);
925 need_drop = true;
926 }
927 spin_unlock(&bundle->channel_lock);
928
929 if (need_drop) {
930 rxrpc_deactivate_bundle(bundle);
931 rxrpc_put_connection(conn);
932 }
933 }
934
935 /*
936 * Drop the active count on a bundle.
937 */
rxrpc_deactivate_bundle(struct rxrpc_bundle * bundle)938 static void rxrpc_deactivate_bundle(struct rxrpc_bundle *bundle)
939 {
940 struct rxrpc_local *local = bundle->params.local;
941 bool need_put = false;
942
943 if (atomic_dec_and_lock(&bundle->active, &local->client_bundles_lock)) {
944 if (!bundle->params.exclusive) {
945 _debug("erase bundle");
946 rb_erase(&bundle->local_node, &local->client_bundles);
947 need_put = true;
948 }
949
950 spin_unlock(&local->client_bundles_lock);
951 if (need_put)
952 rxrpc_put_bundle(bundle);
953 }
954 }
955
956 /*
957 * Clean up a dead client connection.
958 */
rxrpc_kill_client_conn(struct rxrpc_connection * conn)959 static void rxrpc_kill_client_conn(struct rxrpc_connection *conn)
960 {
961 struct rxrpc_local *local = conn->params.local;
962 struct rxrpc_net *rxnet = local->rxnet;
963
964 _enter("C=%x", conn->debug_id);
965
966 trace_rxrpc_client(conn, -1, rxrpc_client_cleanup);
967 atomic_dec(&rxnet->nr_client_conns);
968
969 rxrpc_put_client_connection_id(conn);
970 rxrpc_kill_connection(conn);
971 }
972
973 /*
974 * Clean up a dead client connections.
975 */
rxrpc_put_client_conn(struct rxrpc_connection * conn)976 void rxrpc_put_client_conn(struct rxrpc_connection *conn)
977 {
978 const void *here = __builtin_return_address(0);
979 unsigned int debug_id = conn->debug_id;
980 bool dead;
981 int r;
982
983 dead = __refcount_dec_and_test(&conn->ref, &r);
984 trace_rxrpc_conn(debug_id, rxrpc_conn_put_client, r - 1, here);
985 if (dead)
986 rxrpc_kill_client_conn(conn);
987 }
988
989 /*
990 * Discard expired client connections from the idle list. Each conn in the
991 * idle list has been exposed and holds an extra ref because of that.
992 *
993 * This may be called from conn setup or from a work item so cannot be
994 * considered non-reentrant.
995 */
rxrpc_discard_expired_client_conns(struct work_struct * work)996 void rxrpc_discard_expired_client_conns(struct work_struct *work)
997 {
998 struct rxrpc_connection *conn;
999 struct rxrpc_net *rxnet =
1000 container_of(work, struct rxrpc_net, client_conn_reaper);
1001 unsigned long expiry, conn_expires_at, now;
1002 unsigned int nr_conns;
1003
1004 _enter("");
1005
1006 if (list_empty(&rxnet->idle_client_conns)) {
1007 _leave(" [empty]");
1008 return;
1009 }
1010
1011 /* Don't double up on the discarding */
1012 if (!spin_trylock(&rxnet->client_conn_discard_lock)) {
1013 _leave(" [already]");
1014 return;
1015 }
1016
1017 /* We keep an estimate of what the number of conns ought to be after
1018 * we've discarded some so that we don't overdo the discarding.
1019 */
1020 nr_conns = atomic_read(&rxnet->nr_client_conns);
1021
1022 next:
1023 spin_lock(&rxnet->client_conn_cache_lock);
1024
1025 if (list_empty(&rxnet->idle_client_conns))
1026 goto out;
1027
1028 conn = list_entry(rxnet->idle_client_conns.next,
1029 struct rxrpc_connection, cache_link);
1030
1031 if (!rxnet->kill_all_client_conns) {
1032 /* If the number of connections is over the reap limit, we
1033 * expedite discard by reducing the expiry timeout. We must,
1034 * however, have at least a short grace period to be able to do
1035 * final-ACK or ABORT retransmission.
1036 */
1037 expiry = rxrpc_conn_idle_client_expiry;
1038 if (nr_conns > rxrpc_reap_client_connections)
1039 expiry = rxrpc_conn_idle_client_fast_expiry;
1040 if (conn->params.local->service_closed)
1041 expiry = rxrpc_closed_conn_expiry * HZ;
1042
1043 conn_expires_at = conn->idle_timestamp + expiry;
1044
1045 now = READ_ONCE(jiffies);
1046 if (time_after(conn_expires_at, now))
1047 goto not_yet_expired;
1048 }
1049
1050 trace_rxrpc_client(conn, -1, rxrpc_client_discard);
1051 list_del_init(&conn->cache_link);
1052
1053 spin_unlock(&rxnet->client_conn_cache_lock);
1054
1055 rxrpc_unbundle_conn(conn);
1056 rxrpc_put_connection(conn); /* Drop the ->cache_link ref */
1057
1058 nr_conns--;
1059 goto next;
1060
1061 not_yet_expired:
1062 /* The connection at the front of the queue hasn't yet expired, so
1063 * schedule the work item for that point if we discarded something.
1064 *
1065 * We don't worry if the work item is already scheduled - it can look
1066 * after rescheduling itself at a later time. We could cancel it, but
1067 * then things get messier.
1068 */
1069 _debug("not yet");
1070 if (!rxnet->kill_all_client_conns)
1071 timer_reduce(&rxnet->client_conn_reap_timer, conn_expires_at);
1072
1073 out:
1074 spin_unlock(&rxnet->client_conn_cache_lock);
1075 spin_unlock(&rxnet->client_conn_discard_lock);
1076 _leave("");
1077 }
1078
1079 /*
1080 * Preemptively destroy all the client connection records rather than waiting
1081 * for them to time out
1082 */
rxrpc_destroy_all_client_connections(struct rxrpc_net * rxnet)1083 void rxrpc_destroy_all_client_connections(struct rxrpc_net *rxnet)
1084 {
1085 _enter("");
1086
1087 spin_lock(&rxnet->client_conn_cache_lock);
1088 rxnet->kill_all_client_conns = true;
1089 spin_unlock(&rxnet->client_conn_cache_lock);
1090
1091 del_timer_sync(&rxnet->client_conn_reap_timer);
1092
1093 if (!rxrpc_queue_work(&rxnet->client_conn_reaper))
1094 _debug("destroy: queue failed");
1095
1096 _leave("");
1097 }
1098
1099 /*
1100 * Clean up the client connections on a local endpoint.
1101 */
rxrpc_clean_up_local_conns(struct rxrpc_local * local)1102 void rxrpc_clean_up_local_conns(struct rxrpc_local *local)
1103 {
1104 struct rxrpc_connection *conn, *tmp;
1105 struct rxrpc_net *rxnet = local->rxnet;
1106 LIST_HEAD(graveyard);
1107
1108 _enter("");
1109
1110 spin_lock(&rxnet->client_conn_cache_lock);
1111
1112 list_for_each_entry_safe(conn, tmp, &rxnet->idle_client_conns,
1113 cache_link) {
1114 if (conn->params.local == local) {
1115 trace_rxrpc_client(conn, -1, rxrpc_client_discard);
1116 list_move(&conn->cache_link, &graveyard);
1117 }
1118 }
1119
1120 spin_unlock(&rxnet->client_conn_cache_lock);
1121
1122 while (!list_empty(&graveyard)) {
1123 conn = list_entry(graveyard.next,
1124 struct rxrpc_connection, cache_link);
1125 list_del_init(&conn->cache_link);
1126 rxrpc_unbundle_conn(conn);
1127 rxrpc_put_connection(conn);
1128 }
1129
1130 _leave(" [culled]");
1131 }
1132