Loading...
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
37static void rxrpc_activate_bundle(struct rxrpc_bundle *bundle)
38{
39 atomic_inc(&bundle->active);
40}
41
42/*
43 * Release a connection ID for a client connection.
44 */
45static void rxrpc_put_client_connection_id(struct rxrpc_local *local,
46 struct rxrpc_connection *conn)
47{
48 idr_remove(&local->conn_ids, conn->proto.cid >> RXRPC_CIDSHIFT);
49}
50
51/*
52 * Destroy the client connection ID tree.
53 */
54static void rxrpc_destroy_client_conn_ids(struct rxrpc_local *local)
55{
56 struct rxrpc_connection *conn;
57 int id;
58
59 if (!idr_is_empty(&local->conn_ids)) {
60 idr_for_each_entry(&local->conn_ids, conn, id) {
61 pr_err("AF_RXRPC: Leaked client conn %p {%d}\n",
62 conn, refcount_read(&conn->ref));
63 }
64 BUG();
65 }
66
67 idr_destroy(&local->conn_ids);
68}
69
70/*
71 * Allocate a connection bundle.
72 */
73static struct rxrpc_bundle *rxrpc_alloc_bundle(struct rxrpc_call *call,
74 gfp_t gfp)
75{
76 struct rxrpc_bundle *bundle;
77
78 bundle = kzalloc(sizeof(*bundle), gfp);
79 if (bundle) {
80 bundle->local = call->local;
81 bundle->peer = rxrpc_get_peer(call->peer, rxrpc_peer_get_bundle);
82 bundle->key = key_get(call->key);
83 bundle->security = call->security;
84 bundle->exclusive = test_bit(RXRPC_CALL_EXCLUSIVE, &call->flags);
85 bundle->upgrade = test_bit(RXRPC_CALL_UPGRADE, &call->flags);
86 bundle->service_id = call->dest_srx.srx_service;
87 bundle->security_level = call->security_level;
88 refcount_set(&bundle->ref, 1);
89 atomic_set(&bundle->active, 1);
90 INIT_LIST_HEAD(&bundle->waiting_calls);
91 trace_rxrpc_bundle(bundle->debug_id, 1, rxrpc_bundle_new);
92 }
93 return bundle;
94}
95
96struct rxrpc_bundle *rxrpc_get_bundle(struct rxrpc_bundle *bundle,
97 enum rxrpc_bundle_trace why)
98{
99 int r;
100
101 __refcount_inc(&bundle->ref, &r);
102 trace_rxrpc_bundle(bundle->debug_id, r + 1, why);
103 return bundle;
104}
105
106static void rxrpc_free_bundle(struct rxrpc_bundle *bundle)
107{
108 trace_rxrpc_bundle(bundle->debug_id, 1, rxrpc_bundle_free);
109 rxrpc_put_peer(bundle->peer, rxrpc_peer_put_bundle);
110 key_put(bundle->key);
111 kfree(bundle);
112}
113
114void rxrpc_put_bundle(struct rxrpc_bundle *bundle, enum rxrpc_bundle_trace why)
115{
116 unsigned int id;
117 bool dead;
118 int r;
119
120 if (bundle) {
121 id = bundle->debug_id;
122 dead = __refcount_dec_and_test(&bundle->ref, &r);
123 trace_rxrpc_bundle(id, r - 1, why);
124 if (dead)
125 rxrpc_free_bundle(bundle);
126 }
127}
128
129/*
130 * Get rid of outstanding client connection preallocations when a local
131 * endpoint is destroyed.
132 */
133void rxrpc_purge_client_connections(struct rxrpc_local *local)
134{
135 rxrpc_destroy_client_conn_ids(local);
136}
137
138/*
139 * Allocate a client connection.
140 */
141static struct rxrpc_connection *
142rxrpc_alloc_client_connection(struct rxrpc_bundle *bundle)
143{
144 struct rxrpc_connection *conn;
145 struct rxrpc_local *local = bundle->local;
146 struct rxrpc_net *rxnet = local->rxnet;
147 int id;
148
149 _enter("");
150
151 conn = rxrpc_alloc_connection(rxnet, GFP_ATOMIC | __GFP_NOWARN);
152 if (!conn)
153 return ERR_PTR(-ENOMEM);
154
155 id = idr_alloc_cyclic(&local->conn_ids, conn, 1, 0x40000000,
156 GFP_ATOMIC | __GFP_NOWARN);
157 if (id < 0) {
158 kfree(conn);
159 return ERR_PTR(id);
160 }
161
162 refcount_set(&conn->ref, 1);
163 conn->proto.cid = id << RXRPC_CIDSHIFT;
164 conn->proto.epoch = local->rxnet->epoch;
165 conn->out_clientflag = RXRPC_CLIENT_INITIATED;
166 conn->bundle = rxrpc_get_bundle(bundle, rxrpc_bundle_get_client_conn);
167 conn->local = rxrpc_get_local(bundle->local, rxrpc_local_get_client_conn);
168 conn->peer = rxrpc_get_peer(bundle->peer, rxrpc_peer_get_client_conn);
169 conn->key = key_get(bundle->key);
170 conn->security = bundle->security;
171 conn->exclusive = bundle->exclusive;
172 conn->upgrade = bundle->upgrade;
173 conn->orig_service_id = bundle->service_id;
174 conn->security_level = bundle->security_level;
175 conn->state = RXRPC_CONN_CLIENT_UNSECURED;
176 conn->service_id = conn->orig_service_id;
177
178 if (conn->security == &rxrpc_no_security)
179 conn->state = RXRPC_CONN_CLIENT;
180
181 atomic_inc(&rxnet->nr_conns);
182 write_lock(&rxnet->conn_lock);
183 list_add_tail(&conn->proc_link, &rxnet->conn_proc_list);
184 write_unlock(&rxnet->conn_lock);
185
186 rxrpc_see_connection(conn, rxrpc_conn_new_client);
187
188 atomic_inc(&rxnet->nr_client_conns);
189 trace_rxrpc_client(conn, -1, rxrpc_client_alloc);
190 return conn;
191}
192
193/*
194 * Determine if a connection may be reused.
195 */
196static bool rxrpc_may_reuse_conn(struct rxrpc_connection *conn)
197{
198 struct rxrpc_net *rxnet;
199 int id_cursor, id, distance, limit;
200
201 if (!conn)
202 goto dont_reuse;
203
204 rxnet = conn->rxnet;
205 if (test_bit(RXRPC_CONN_DONT_REUSE, &conn->flags))
206 goto dont_reuse;
207
208 if ((conn->state != RXRPC_CONN_CLIENT_UNSECURED &&
209 conn->state != RXRPC_CONN_CLIENT) ||
210 conn->proto.epoch != rxnet->epoch)
211 goto mark_dont_reuse;
212
213 /* The IDR tree gets very expensive on memory if the connection IDs are
214 * widely scattered throughout the number space, so we shall want to
215 * kill off connections that, say, have an ID more than about four
216 * times the maximum number of client conns away from the current
217 * allocation point to try and keep the IDs concentrated.
218 */
219 id_cursor = idr_get_cursor(&conn->local->conn_ids);
220 id = conn->proto.cid >> RXRPC_CIDSHIFT;
221 distance = id - id_cursor;
222 if (distance < 0)
223 distance = -distance;
224 limit = max_t(unsigned long, atomic_read(&rxnet->nr_conns) * 4, 1024);
225 if (distance > limit)
226 goto mark_dont_reuse;
227
228 return true;
229
230mark_dont_reuse:
231 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
232dont_reuse:
233 return false;
234}
235
236/*
237 * Look up the conn bundle that matches the connection parameters, adding it if
238 * it doesn't yet exist.
239 */
240int rxrpc_look_up_bundle(struct rxrpc_call *call, gfp_t gfp)
241{
242 static atomic_t rxrpc_bundle_id;
243 struct rxrpc_bundle *bundle, *candidate;
244 struct rxrpc_local *local = call->local;
245 struct rb_node *p, **pp, *parent;
246 long diff;
247 bool upgrade = test_bit(RXRPC_CALL_UPGRADE, &call->flags);
248
249 _enter("{%px,%x,%u,%u}",
250 call->peer, key_serial(call->key), call->security_level,
251 upgrade);
252
253 if (test_bit(RXRPC_CALL_EXCLUSIVE, &call->flags)) {
254 call->bundle = rxrpc_alloc_bundle(call, gfp);
255 return call->bundle ? 0 : -ENOMEM;
256 }
257
258 /* First, see if the bundle is already there. */
259 _debug("search 1");
260 spin_lock(&local->client_bundles_lock);
261 p = local->client_bundles.rb_node;
262 while (p) {
263 bundle = rb_entry(p, struct rxrpc_bundle, local_node);
264
265#define cmp(X, Y) ((long)(X) - (long)(Y))
266 diff = (cmp(bundle->peer, call->peer) ?:
267 cmp(bundle->key, call->key) ?:
268 cmp(bundle->security_level, call->security_level) ?:
269 cmp(bundle->upgrade, upgrade));
270#undef cmp
271 if (diff < 0)
272 p = p->rb_left;
273 else if (diff > 0)
274 p = p->rb_right;
275 else
276 goto found_bundle;
277 }
278 spin_unlock(&local->client_bundles_lock);
279 _debug("not found");
280
281 /* It wasn't. We need to add one. */
282 candidate = rxrpc_alloc_bundle(call, gfp);
283 if (!candidate)
284 return -ENOMEM;
285
286 _debug("search 2");
287 spin_lock(&local->client_bundles_lock);
288 pp = &local->client_bundles.rb_node;
289 parent = NULL;
290 while (*pp) {
291 parent = *pp;
292 bundle = rb_entry(parent, struct rxrpc_bundle, local_node);
293
294#define cmp(X, Y) ((long)(X) - (long)(Y))
295 diff = (cmp(bundle->peer, call->peer) ?:
296 cmp(bundle->key, call->key) ?:
297 cmp(bundle->security_level, call->security_level) ?:
298 cmp(bundle->upgrade, upgrade));
299#undef cmp
300 if (diff < 0)
301 pp = &(*pp)->rb_left;
302 else if (diff > 0)
303 pp = &(*pp)->rb_right;
304 else
305 goto found_bundle_free;
306 }
307
308 _debug("new bundle");
309 candidate->debug_id = atomic_inc_return(&rxrpc_bundle_id);
310 rb_link_node(&candidate->local_node, parent, pp);
311 rb_insert_color(&candidate->local_node, &local->client_bundles);
312 call->bundle = rxrpc_get_bundle(candidate, rxrpc_bundle_get_client_call);
313 spin_unlock(&local->client_bundles_lock);
314 _leave(" = B=%u [new]", call->bundle->debug_id);
315 return 0;
316
317found_bundle_free:
318 rxrpc_free_bundle(candidate);
319found_bundle:
320 call->bundle = rxrpc_get_bundle(bundle, rxrpc_bundle_get_client_call);
321 rxrpc_activate_bundle(bundle);
322 spin_unlock(&local->client_bundles_lock);
323 _leave(" = B=%u [found]", call->bundle->debug_id);
324 return 0;
325}
326
327/*
328 * Allocate a new connection and add it into a bundle.
329 */
330static bool rxrpc_add_conn_to_bundle(struct rxrpc_bundle *bundle,
331 unsigned int slot)
332{
333 struct rxrpc_connection *conn, *old;
334 unsigned int shift = slot * RXRPC_MAXCALLS;
335 unsigned int i;
336
337 old = bundle->conns[slot];
338 if (old) {
339 bundle->conns[slot] = NULL;
340 trace_rxrpc_client(old, -1, rxrpc_client_replace);
341 rxrpc_put_connection(old, rxrpc_conn_put_noreuse);
342 }
343
344 conn = rxrpc_alloc_client_connection(bundle);
345 if (IS_ERR(conn)) {
346 bundle->alloc_error = PTR_ERR(conn);
347 return false;
348 }
349
350 rxrpc_activate_bundle(bundle);
351 conn->bundle_shift = shift;
352 bundle->conns[slot] = conn;
353 for (i = 0; i < RXRPC_MAXCALLS; i++)
354 set_bit(shift + i, &bundle->avail_chans);
355 return true;
356}
357
358/*
359 * Add a connection to a bundle if there are no usable connections or we have
360 * connections waiting for extra capacity.
361 */
362static bool rxrpc_bundle_has_space(struct rxrpc_bundle *bundle)
363{
364 int slot = -1, i, usable;
365
366 _enter("");
367
368 bundle->alloc_error = 0;
369
370 /* See if there are any usable connections. */
371 usable = 0;
372 for (i = 0; i < ARRAY_SIZE(bundle->conns); i++) {
373 if (rxrpc_may_reuse_conn(bundle->conns[i]))
374 usable++;
375 else if (slot == -1)
376 slot = i;
377 }
378
379 if (!usable && bundle->upgrade)
380 bundle->try_upgrade = true;
381
382 if (!usable)
383 goto alloc_conn;
384
385 if (!bundle->avail_chans &&
386 !bundle->try_upgrade &&
387 usable < ARRAY_SIZE(bundle->conns))
388 goto alloc_conn;
389
390 _leave("");
391 return usable;
392
393alloc_conn:
394 return slot >= 0 ? rxrpc_add_conn_to_bundle(bundle, slot) : false;
395}
396
397/*
398 * Assign a channel to the call at the front of the queue and wake the call up.
399 * We don't increment the callNumber counter until this number has been exposed
400 * to the world.
401 */
402static void rxrpc_activate_one_channel(struct rxrpc_connection *conn,
403 unsigned int channel)
404{
405 struct rxrpc_channel *chan = &conn->channels[channel];
406 struct rxrpc_bundle *bundle = conn->bundle;
407 struct rxrpc_call *call = list_entry(bundle->waiting_calls.next,
408 struct rxrpc_call, wait_link);
409 u32 call_id = chan->call_counter + 1;
410
411 _enter("C=%x,%u", conn->debug_id, channel);
412
413 list_del_init(&call->wait_link);
414
415 trace_rxrpc_client(conn, channel, rxrpc_client_chan_activate);
416
417 /* Cancel the final ACK on the previous call if it hasn't been sent yet
418 * as the DATA packet will implicitly ACK it.
419 */
420 clear_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags);
421 clear_bit(conn->bundle_shift + channel, &bundle->avail_chans);
422
423 rxrpc_see_call(call, rxrpc_call_see_activate_client);
424 call->conn = rxrpc_get_connection(conn, rxrpc_conn_get_activate_call);
425 call->cid = conn->proto.cid | channel;
426 call->call_id = call_id;
427 call->dest_srx.srx_service = conn->service_id;
428 call->cong_ssthresh = call->peer->cong_ssthresh;
429 if (call->cong_cwnd >= call->cong_ssthresh)
430 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
431 else
432 call->cong_mode = RXRPC_CALL_SLOW_START;
433
434 chan->call_id = call_id;
435 chan->call_debug_id = call->debug_id;
436 chan->call = call;
437
438 rxrpc_see_call(call, rxrpc_call_see_connected);
439 trace_rxrpc_connect_call(call);
440 call->tx_last_sent = ktime_get_real();
441 rxrpc_start_call_timer(call);
442 rxrpc_set_call_state(call, RXRPC_CALL_CLIENT_SEND_REQUEST);
443 wake_up(&call->waitq);
444}
445
446/*
447 * Remove a connection from the idle list if it's on it.
448 */
449static void rxrpc_unidle_conn(struct rxrpc_connection *conn)
450{
451 if (!list_empty(&conn->cache_link)) {
452 list_del_init(&conn->cache_link);
453 rxrpc_put_connection(conn, rxrpc_conn_put_unidle);
454 }
455}
456
457/*
458 * Assign channels and callNumbers to waiting calls.
459 */
460static void rxrpc_activate_channels(struct rxrpc_bundle *bundle)
461{
462 struct rxrpc_connection *conn;
463 unsigned long avail, mask;
464 unsigned int channel, slot;
465
466 trace_rxrpc_client(NULL, -1, rxrpc_client_activate_chans);
467
468 if (bundle->try_upgrade)
469 mask = 1;
470 else
471 mask = ULONG_MAX;
472
473 while (!list_empty(&bundle->waiting_calls)) {
474 avail = bundle->avail_chans & mask;
475 if (!avail)
476 break;
477 channel = __ffs(avail);
478 clear_bit(channel, &bundle->avail_chans);
479
480 slot = channel / RXRPC_MAXCALLS;
481 conn = bundle->conns[slot];
482 if (!conn)
483 break;
484
485 if (bundle->try_upgrade)
486 set_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags);
487 rxrpc_unidle_conn(conn);
488
489 channel &= (RXRPC_MAXCALLS - 1);
490 conn->act_chans |= 1 << channel;
491 rxrpc_activate_one_channel(conn, channel);
492 }
493}
494
495/*
496 * Connect waiting channels (called from the I/O thread).
497 */
498void rxrpc_connect_client_calls(struct rxrpc_local *local)
499{
500 struct rxrpc_call *call;
501
502 while ((call = list_first_entry_or_null(&local->new_client_calls,
503 struct rxrpc_call, wait_link))
504 ) {
505 struct rxrpc_bundle *bundle = call->bundle;
506
507 spin_lock(&local->client_call_lock);
508 list_move_tail(&call->wait_link, &bundle->waiting_calls);
509 spin_unlock(&local->client_call_lock);
510
511 if (rxrpc_bundle_has_space(bundle))
512 rxrpc_activate_channels(bundle);
513 }
514}
515
516/*
517 * Note that a call, and thus a connection, is about to be exposed to the
518 * world.
519 */
520void rxrpc_expose_client_call(struct rxrpc_call *call)
521{
522 unsigned int channel = call->cid & RXRPC_CHANNELMASK;
523 struct rxrpc_connection *conn = call->conn;
524 struct rxrpc_channel *chan = &conn->channels[channel];
525
526 if (!test_and_set_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
527 /* Mark the call ID as being used. If the callNumber counter
528 * exceeds ~2 billion, we kill the connection after its
529 * outstanding calls have finished so that the counter doesn't
530 * wrap.
531 */
532 chan->call_counter++;
533 if (chan->call_counter >= INT_MAX)
534 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
535 trace_rxrpc_client(conn, channel, rxrpc_client_exposed);
536
537 spin_lock(&call->peer->lock);
538 hlist_add_head(&call->error_link, &call->peer->error_targets);
539 spin_unlock(&call->peer->lock);
540 }
541}
542
543/*
544 * Set the reap timer.
545 */
546static void rxrpc_set_client_reap_timer(struct rxrpc_local *local)
547{
548 if (!local->kill_all_client_conns) {
549 unsigned long now = jiffies;
550 unsigned long reap_at = now + rxrpc_conn_idle_client_expiry;
551
552 if (local->rxnet->live)
553 timer_reduce(&local->client_conn_reap_timer, reap_at);
554 }
555}
556
557/*
558 * Disconnect a client call.
559 */
560void rxrpc_disconnect_client_call(struct rxrpc_bundle *bundle, struct rxrpc_call *call)
561{
562 struct rxrpc_connection *conn;
563 struct rxrpc_channel *chan = NULL;
564 struct rxrpc_local *local = bundle->local;
565 unsigned int channel;
566 bool may_reuse;
567 u32 cid;
568
569 _enter("c=%x", call->debug_id);
570
571 /* Calls that have never actually been assigned a channel can simply be
572 * discarded.
573 */
574 conn = call->conn;
575 if (!conn) {
576 _debug("call is waiting");
577 ASSERTCMP(call->call_id, ==, 0);
578 ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags));
579 list_del_init(&call->wait_link);
580 return;
581 }
582
583 cid = call->cid;
584 channel = cid & RXRPC_CHANNELMASK;
585 chan = &conn->channels[channel];
586 trace_rxrpc_client(conn, channel, rxrpc_client_chan_disconnect);
587
588 if (WARN_ON(chan->call != call))
589 return;
590
591 may_reuse = rxrpc_may_reuse_conn(conn);
592
593 /* If a client call was exposed to the world, we save the result for
594 * retransmission.
595 *
596 * We use a barrier here so that the call number and abort code can be
597 * read without needing to take a lock.
598 *
599 * TODO: Make the incoming packet handler check this and handle
600 * terminal retransmission without requiring access to the call.
601 */
602 if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
603 _debug("exposed %u,%u", call->call_id, call->abort_code);
604 __rxrpc_disconnect_call(conn, call);
605
606 if (test_and_clear_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags)) {
607 trace_rxrpc_client(conn, channel, rxrpc_client_to_active);
608 bundle->try_upgrade = false;
609 if (may_reuse)
610 rxrpc_activate_channels(bundle);
611 }
612 }
613
614 /* See if we can pass the channel directly to another call. */
615 if (may_reuse && !list_empty(&bundle->waiting_calls)) {
616 trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass);
617 rxrpc_activate_one_channel(conn, channel);
618 return;
619 }
620
621 /* Schedule the final ACK to be transmitted in a short while so that it
622 * can be skipped if we find a follow-on call. The first DATA packet
623 * of the follow on call will implicitly ACK this call.
624 */
625 if (call->completion == RXRPC_CALL_SUCCEEDED &&
626 test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
627 unsigned long final_ack_at = jiffies + 2;
628
629 WRITE_ONCE(chan->final_ack_at, final_ack_at);
630 smp_wmb(); /* vs rxrpc_process_delayed_final_acks() */
631 set_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags);
632 rxrpc_reduce_conn_timer(conn, final_ack_at);
633 }
634
635 /* Deactivate the channel. */
636 chan->call = NULL;
637 set_bit(conn->bundle_shift + channel, &conn->bundle->avail_chans);
638 conn->act_chans &= ~(1 << channel);
639
640 /* If no channels remain active, then put the connection on the idle
641 * list for a short while. Give it a ref to stop it going away if it
642 * becomes unbundled.
643 */
644 if (!conn->act_chans) {
645 trace_rxrpc_client(conn, channel, rxrpc_client_to_idle);
646 conn->idle_timestamp = jiffies;
647
648 rxrpc_get_connection(conn, rxrpc_conn_get_idle);
649 list_move_tail(&conn->cache_link, &local->idle_client_conns);
650
651 rxrpc_set_client_reap_timer(local);
652 }
653}
654
655/*
656 * Remove a connection from a bundle.
657 */
658static void rxrpc_unbundle_conn(struct rxrpc_connection *conn)
659{
660 struct rxrpc_bundle *bundle = conn->bundle;
661 unsigned int bindex;
662 int i;
663
664 _enter("C=%x", conn->debug_id);
665
666 if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
667 rxrpc_process_delayed_final_acks(conn, true);
668
669 bindex = conn->bundle_shift / RXRPC_MAXCALLS;
670 if (bundle->conns[bindex] == conn) {
671 _debug("clear slot %u", bindex);
672 bundle->conns[bindex] = NULL;
673 for (i = 0; i < RXRPC_MAXCALLS; i++)
674 clear_bit(conn->bundle_shift + i, &bundle->avail_chans);
675 rxrpc_put_client_connection_id(bundle->local, conn);
676 rxrpc_deactivate_bundle(bundle);
677 rxrpc_put_connection(conn, rxrpc_conn_put_unbundle);
678 }
679}
680
681/*
682 * Drop the active count on a bundle.
683 */
684void rxrpc_deactivate_bundle(struct rxrpc_bundle *bundle)
685{
686 struct rxrpc_local *local;
687 bool need_put = false;
688
689 if (!bundle)
690 return;
691
692 local = bundle->local;
693 if (atomic_dec_and_lock(&bundle->active, &local->client_bundles_lock)) {
694 if (!bundle->exclusive) {
695 _debug("erase bundle");
696 rb_erase(&bundle->local_node, &local->client_bundles);
697 need_put = true;
698 }
699
700 spin_unlock(&local->client_bundles_lock);
701 if (need_put)
702 rxrpc_put_bundle(bundle, rxrpc_bundle_put_discard);
703 }
704}
705
706/*
707 * Clean up a dead client connection.
708 */
709void rxrpc_kill_client_conn(struct rxrpc_connection *conn)
710{
711 struct rxrpc_local *local = conn->local;
712 struct rxrpc_net *rxnet = local->rxnet;
713
714 _enter("C=%x", conn->debug_id);
715
716 trace_rxrpc_client(conn, -1, rxrpc_client_cleanup);
717 atomic_dec(&rxnet->nr_client_conns);
718
719 rxrpc_put_client_connection_id(local, conn);
720}
721
722/*
723 * Discard expired client connections from the idle list. Each conn in the
724 * idle list has been exposed and holds an extra ref because of that.
725 *
726 * This may be called from conn setup or from a work item so cannot be
727 * considered non-reentrant.
728 */
729void rxrpc_discard_expired_client_conns(struct rxrpc_local *local)
730{
731 struct rxrpc_connection *conn;
732 unsigned long expiry, conn_expires_at, now;
733 unsigned int nr_conns;
734
735 _enter("");
736
737 /* We keep an estimate of what the number of conns ought to be after
738 * we've discarded some so that we don't overdo the discarding.
739 */
740 nr_conns = atomic_read(&local->rxnet->nr_client_conns);
741
742next:
743 conn = list_first_entry_or_null(&local->idle_client_conns,
744 struct rxrpc_connection, cache_link);
745 if (!conn)
746 return;
747
748 if (!local->kill_all_client_conns) {
749 /* If the number of connections is over the reap limit, we
750 * expedite discard by reducing the expiry timeout. We must,
751 * however, have at least a short grace period to be able to do
752 * final-ACK or ABORT retransmission.
753 */
754 expiry = rxrpc_conn_idle_client_expiry;
755 if (nr_conns > rxrpc_reap_client_connections)
756 expiry = rxrpc_conn_idle_client_fast_expiry;
757 if (conn->local->service_closed)
758 expiry = rxrpc_closed_conn_expiry * HZ;
759
760 conn_expires_at = conn->idle_timestamp + expiry;
761
762 now = READ_ONCE(jiffies);
763 if (time_after(conn_expires_at, now))
764 goto not_yet_expired;
765 }
766
767 atomic_dec(&conn->active);
768 trace_rxrpc_client(conn, -1, rxrpc_client_discard);
769 list_del_init(&conn->cache_link);
770
771 rxrpc_unbundle_conn(conn);
772 /* Drop the ->cache_link ref */
773 rxrpc_put_connection(conn, rxrpc_conn_put_discard_idle);
774
775 nr_conns--;
776 goto next;
777
778not_yet_expired:
779 /* The connection at the front of the queue hasn't yet expired, so
780 * schedule the work item for that point if we discarded something.
781 *
782 * We don't worry if the work item is already scheduled - it can look
783 * after rescheduling itself at a later time. We could cancel it, but
784 * then things get messier.
785 */
786 _debug("not yet");
787 if (!local->kill_all_client_conns)
788 timer_reduce(&local->client_conn_reap_timer, conn_expires_at);
789
790 _leave("");
791}
792
793/*
794 * Clean up the client connections on a local endpoint.
795 */
796void rxrpc_clean_up_local_conns(struct rxrpc_local *local)
797{
798 struct rxrpc_connection *conn;
799
800 _enter("");
801
802 local->kill_all_client_conns = true;
803
804 del_timer_sync(&local->client_conn_reap_timer);
805
806 while ((conn = list_first_entry_or_null(&local->idle_client_conns,
807 struct rxrpc_connection, cache_link))) {
808 list_del_init(&conn->cache_link);
809 atomic_dec(&conn->active);
810 trace_rxrpc_client(conn, -1, rxrpc_client_discard);
811 rxrpc_unbundle_conn(conn);
812 rxrpc_put_connection(conn, rxrpc_conn_put_local_dead);
813 }
814
815 _leave(" [culled]");
816}
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
37static void rxrpc_activate_bundle(struct rxrpc_bundle *bundle)
38{
39 atomic_inc(&bundle->active);
40}
41
42/*
43 * Release a connection ID for a client connection.
44 */
45static void rxrpc_put_client_connection_id(struct rxrpc_local *local,
46 struct rxrpc_connection *conn)
47{
48 idr_remove(&local->conn_ids, conn->proto.cid >> RXRPC_CIDSHIFT);
49}
50
51/*
52 * Destroy the client connection ID tree.
53 */
54static void rxrpc_destroy_client_conn_ids(struct rxrpc_local *local)
55{
56 struct rxrpc_connection *conn;
57 int id;
58
59 if (!idr_is_empty(&local->conn_ids)) {
60 idr_for_each_entry(&local->conn_ids, conn, id) {
61 pr_err("AF_RXRPC: Leaked client conn %p {%d}\n",
62 conn, refcount_read(&conn->ref));
63 }
64 BUG();
65 }
66
67 idr_destroy(&local->conn_ids);
68}
69
70/*
71 * Allocate a connection bundle.
72 */
73static struct rxrpc_bundle *rxrpc_alloc_bundle(struct rxrpc_call *call,
74 gfp_t gfp)
75{
76 static atomic_t rxrpc_bundle_id;
77 struct rxrpc_bundle *bundle;
78
79 bundle = kzalloc(sizeof(*bundle), gfp);
80 if (bundle) {
81 bundle->local = call->local;
82 bundle->peer = rxrpc_get_peer(call->peer, rxrpc_peer_get_bundle);
83 bundle->key = key_get(call->key);
84 bundle->security = call->security;
85 bundle->exclusive = test_bit(RXRPC_CALL_EXCLUSIVE, &call->flags);
86 bundle->upgrade = test_bit(RXRPC_CALL_UPGRADE, &call->flags);
87 bundle->service_id = call->dest_srx.srx_service;
88 bundle->security_level = call->security_level;
89 bundle->debug_id = atomic_inc_return(&rxrpc_bundle_id);
90 refcount_set(&bundle->ref, 1);
91 atomic_set(&bundle->active, 1);
92 INIT_LIST_HEAD(&bundle->waiting_calls);
93 trace_rxrpc_bundle(bundle->debug_id, 1, rxrpc_bundle_new);
94
95 write_lock(&bundle->local->rxnet->conn_lock);
96 list_add_tail(&bundle->proc_link, &bundle->local->rxnet->bundle_proc_list);
97 write_unlock(&bundle->local->rxnet->conn_lock);
98 }
99 return bundle;
100}
101
102struct rxrpc_bundle *rxrpc_get_bundle(struct rxrpc_bundle *bundle,
103 enum rxrpc_bundle_trace why)
104{
105 int r;
106
107 __refcount_inc(&bundle->ref, &r);
108 trace_rxrpc_bundle(bundle->debug_id, r + 1, why);
109 return bundle;
110}
111
112static void rxrpc_free_bundle(struct rxrpc_bundle *bundle)
113{
114 trace_rxrpc_bundle(bundle->debug_id, refcount_read(&bundle->ref),
115 rxrpc_bundle_free);
116 write_lock(&bundle->local->rxnet->conn_lock);
117 list_del(&bundle->proc_link);
118 write_unlock(&bundle->local->rxnet->conn_lock);
119 rxrpc_put_peer(bundle->peer, rxrpc_peer_put_bundle);
120 key_put(bundle->key);
121 kfree(bundle);
122}
123
124void rxrpc_put_bundle(struct rxrpc_bundle *bundle, enum rxrpc_bundle_trace why)
125{
126 unsigned int id;
127 bool dead;
128 int r;
129
130 if (bundle) {
131 id = bundle->debug_id;
132 dead = __refcount_dec_and_test(&bundle->ref, &r);
133 trace_rxrpc_bundle(id, r - 1, why);
134 if (dead)
135 rxrpc_free_bundle(bundle);
136 }
137}
138
139/*
140 * Get rid of outstanding client connection preallocations when a local
141 * endpoint is destroyed.
142 */
143void rxrpc_purge_client_connections(struct rxrpc_local *local)
144{
145 rxrpc_destroy_client_conn_ids(local);
146}
147
148/*
149 * Allocate a client connection.
150 */
151static struct rxrpc_connection *
152rxrpc_alloc_client_connection(struct rxrpc_bundle *bundle)
153{
154 struct rxrpc_connection *conn;
155 struct rxrpc_local *local = bundle->local;
156 struct rxrpc_net *rxnet = local->rxnet;
157 int id;
158
159 _enter("");
160
161 conn = rxrpc_alloc_connection(rxnet, GFP_ATOMIC | __GFP_NOWARN);
162 if (!conn)
163 return ERR_PTR(-ENOMEM);
164
165 id = idr_alloc_cyclic(&local->conn_ids, conn, 1, 0x40000000,
166 GFP_ATOMIC | __GFP_NOWARN);
167 if (id < 0) {
168 kfree(conn);
169 return ERR_PTR(id);
170 }
171
172 refcount_set(&conn->ref, 1);
173 conn->proto.cid = id << RXRPC_CIDSHIFT;
174 conn->proto.epoch = local->rxnet->epoch;
175 conn->out_clientflag = RXRPC_CLIENT_INITIATED;
176 conn->bundle = rxrpc_get_bundle(bundle, rxrpc_bundle_get_client_conn);
177 conn->local = rxrpc_get_local(bundle->local, rxrpc_local_get_client_conn);
178 conn->peer = rxrpc_get_peer(bundle->peer, rxrpc_peer_get_client_conn);
179 conn->key = key_get(bundle->key);
180 conn->security = bundle->security;
181 conn->exclusive = bundle->exclusive;
182 conn->upgrade = bundle->upgrade;
183 conn->orig_service_id = bundle->service_id;
184 conn->security_level = bundle->security_level;
185 conn->state = RXRPC_CONN_CLIENT_UNSECURED;
186 conn->service_id = conn->orig_service_id;
187
188 if (conn->security == &rxrpc_no_security)
189 conn->state = RXRPC_CONN_CLIENT;
190
191 atomic_inc(&rxnet->nr_conns);
192 write_lock(&rxnet->conn_lock);
193 list_add_tail(&conn->proc_link, &rxnet->conn_proc_list);
194 write_unlock(&rxnet->conn_lock);
195
196 rxrpc_see_connection(conn, rxrpc_conn_new_client);
197
198 atomic_inc(&rxnet->nr_client_conns);
199 trace_rxrpc_client(conn, -1, rxrpc_client_alloc);
200 return conn;
201}
202
203/*
204 * Determine if a connection may be reused.
205 */
206static bool rxrpc_may_reuse_conn(struct rxrpc_connection *conn)
207{
208 struct rxrpc_net *rxnet;
209 int id_cursor, id, distance, limit;
210
211 if (!conn)
212 goto dont_reuse;
213
214 rxnet = conn->rxnet;
215 if (test_bit(RXRPC_CONN_DONT_REUSE, &conn->flags))
216 goto dont_reuse;
217
218 if ((conn->state != RXRPC_CONN_CLIENT_UNSECURED &&
219 conn->state != RXRPC_CONN_CLIENT) ||
220 conn->proto.epoch != rxnet->epoch)
221 goto mark_dont_reuse;
222
223 /* The IDR tree gets very expensive on memory if the connection IDs are
224 * widely scattered throughout the number space, so we shall want to
225 * kill off connections that, say, have an ID more than about four
226 * times the maximum number of client conns away from the current
227 * allocation point to try and keep the IDs concentrated.
228 */
229 id_cursor = idr_get_cursor(&conn->local->conn_ids);
230 id = conn->proto.cid >> RXRPC_CIDSHIFT;
231 distance = id - id_cursor;
232 if (distance < 0)
233 distance = -distance;
234 limit = max_t(unsigned long, atomic_read(&rxnet->nr_conns) * 4, 1024);
235 if (distance > limit)
236 goto mark_dont_reuse;
237
238 return true;
239
240mark_dont_reuse:
241 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
242dont_reuse:
243 return false;
244}
245
246/*
247 * Look up the conn bundle that matches the connection parameters, adding it if
248 * it doesn't yet exist.
249 */
250int rxrpc_look_up_bundle(struct rxrpc_call *call, gfp_t gfp)
251{
252 struct rxrpc_bundle *bundle, *candidate;
253 struct rxrpc_local *local = call->local;
254 struct rb_node *p, **pp, *parent;
255 long diff;
256 bool upgrade = test_bit(RXRPC_CALL_UPGRADE, &call->flags);
257
258 _enter("{%px,%x,%u,%u}",
259 call->peer, key_serial(call->key), call->security_level,
260 upgrade);
261
262 if (test_bit(RXRPC_CALL_EXCLUSIVE, &call->flags)) {
263 call->bundle = rxrpc_alloc_bundle(call, gfp);
264 return call->bundle ? 0 : -ENOMEM;
265 }
266
267 /* First, see if the bundle is already there. */
268 _debug("search 1");
269 spin_lock(&local->client_bundles_lock);
270 p = local->client_bundles.rb_node;
271 while (p) {
272 bundle = rb_entry(p, struct rxrpc_bundle, local_node);
273
274#define cmp(X, Y) ((long)(X) - (long)(Y))
275 diff = (cmp(bundle->peer, call->peer) ?:
276 cmp(bundle->key, call->key) ?:
277 cmp(bundle->security_level, call->security_level) ?:
278 cmp(bundle->upgrade, upgrade));
279#undef cmp
280 if (diff < 0)
281 p = p->rb_left;
282 else if (diff > 0)
283 p = p->rb_right;
284 else
285 goto found_bundle;
286 }
287 spin_unlock(&local->client_bundles_lock);
288 _debug("not found");
289
290 /* It wasn't. We need to add one. */
291 candidate = rxrpc_alloc_bundle(call, gfp);
292 if (!candidate)
293 return -ENOMEM;
294
295 _debug("search 2");
296 spin_lock(&local->client_bundles_lock);
297 pp = &local->client_bundles.rb_node;
298 parent = NULL;
299 while (*pp) {
300 parent = *pp;
301 bundle = rb_entry(parent, struct rxrpc_bundle, local_node);
302
303#define cmp(X, Y) ((long)(X) - (long)(Y))
304 diff = (cmp(bundle->peer, call->peer) ?:
305 cmp(bundle->key, call->key) ?:
306 cmp(bundle->security_level, call->security_level) ?:
307 cmp(bundle->upgrade, upgrade));
308#undef cmp
309 if (diff < 0)
310 pp = &(*pp)->rb_left;
311 else if (diff > 0)
312 pp = &(*pp)->rb_right;
313 else
314 goto found_bundle_free;
315 }
316
317 _debug("new bundle");
318 rb_link_node(&candidate->local_node, parent, pp);
319 rb_insert_color(&candidate->local_node, &local->client_bundles);
320 call->bundle = rxrpc_get_bundle(candidate, rxrpc_bundle_get_client_call);
321 spin_unlock(&local->client_bundles_lock);
322 _leave(" = B=%u [new]", call->bundle->debug_id);
323 return 0;
324
325found_bundle_free:
326 rxrpc_free_bundle(candidate);
327found_bundle:
328 call->bundle = rxrpc_get_bundle(bundle, rxrpc_bundle_get_client_call);
329 rxrpc_activate_bundle(bundle);
330 spin_unlock(&local->client_bundles_lock);
331 _leave(" = B=%u [found]", call->bundle->debug_id);
332 return 0;
333}
334
335/*
336 * Allocate a new connection and add it into a bundle.
337 */
338static bool rxrpc_add_conn_to_bundle(struct rxrpc_bundle *bundle,
339 unsigned int slot)
340{
341 struct rxrpc_connection *conn, *old;
342 unsigned int shift = slot * RXRPC_MAXCALLS;
343 unsigned int i;
344
345 old = bundle->conns[slot];
346 if (old) {
347 bundle->conns[slot] = NULL;
348 bundle->conn_ids[slot] = 0;
349 trace_rxrpc_client(old, -1, rxrpc_client_replace);
350 rxrpc_put_connection(old, rxrpc_conn_put_noreuse);
351 }
352
353 conn = rxrpc_alloc_client_connection(bundle);
354 if (IS_ERR(conn)) {
355 bundle->alloc_error = PTR_ERR(conn);
356 return false;
357 }
358
359 rxrpc_activate_bundle(bundle);
360 conn->bundle_shift = shift;
361 bundle->conns[slot] = conn;
362 bundle->conn_ids[slot] = conn->debug_id;
363 for (i = 0; i < RXRPC_MAXCALLS; i++)
364 set_bit(shift + i, &bundle->avail_chans);
365 return true;
366}
367
368/*
369 * Add a connection to a bundle if there are no usable connections or we have
370 * connections waiting for extra capacity.
371 */
372static bool rxrpc_bundle_has_space(struct rxrpc_bundle *bundle)
373{
374 int slot = -1, i, usable;
375
376 _enter("");
377
378 bundle->alloc_error = 0;
379
380 /* See if there are any usable connections. */
381 usable = 0;
382 for (i = 0; i < ARRAY_SIZE(bundle->conns); i++) {
383 if (rxrpc_may_reuse_conn(bundle->conns[i]))
384 usable++;
385 else if (slot == -1)
386 slot = i;
387 }
388
389 if (!usable && bundle->upgrade)
390 bundle->try_upgrade = true;
391
392 if (!usable)
393 goto alloc_conn;
394
395 if (!bundle->avail_chans &&
396 !bundle->try_upgrade &&
397 usable < ARRAY_SIZE(bundle->conns))
398 goto alloc_conn;
399
400 _leave("");
401 return usable;
402
403alloc_conn:
404 return slot >= 0 ? rxrpc_add_conn_to_bundle(bundle, slot) : false;
405}
406
407/*
408 * Assign a channel to the call at the front of the queue and wake the call up.
409 * We don't increment the callNumber counter until this number has been exposed
410 * to the world.
411 */
412static void rxrpc_activate_one_channel(struct rxrpc_connection *conn,
413 unsigned int channel)
414{
415 struct rxrpc_channel *chan = &conn->channels[channel];
416 struct rxrpc_bundle *bundle = conn->bundle;
417 struct rxrpc_call *call = list_entry(bundle->waiting_calls.next,
418 struct rxrpc_call, wait_link);
419 u32 call_id = chan->call_counter + 1;
420
421 _enter("C=%x,%u", conn->debug_id, channel);
422
423 list_del_init(&call->wait_link);
424
425 trace_rxrpc_client(conn, channel, rxrpc_client_chan_activate);
426
427 /* Cancel the final ACK on the previous call if it hasn't been sent yet
428 * as the DATA packet will implicitly ACK it.
429 */
430 clear_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags);
431 clear_bit(conn->bundle_shift + channel, &bundle->avail_chans);
432
433 rxrpc_see_call(call, rxrpc_call_see_activate_client);
434 call->conn = rxrpc_get_connection(conn, rxrpc_conn_get_activate_call);
435 call->cid = conn->proto.cid | channel;
436 call->call_id = call_id;
437 call->dest_srx.srx_service = conn->service_id;
438 call->cong_ssthresh = call->peer->cong_ssthresh;
439 if (call->cong_cwnd >= call->cong_ssthresh)
440 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
441 else
442 call->cong_mode = RXRPC_CALL_SLOW_START;
443
444 chan->call_id = call_id;
445 chan->call_debug_id = call->debug_id;
446 chan->call = call;
447
448 rxrpc_see_call(call, rxrpc_call_see_connected);
449 trace_rxrpc_connect_call(call);
450 call->tx_last_sent = ktime_get_real();
451 rxrpc_start_call_timer(call);
452 rxrpc_set_call_state(call, RXRPC_CALL_CLIENT_SEND_REQUEST);
453 wake_up(&call->waitq);
454}
455
456/*
457 * Remove a connection from the idle list if it's on it.
458 */
459static void rxrpc_unidle_conn(struct rxrpc_connection *conn)
460{
461 if (!list_empty(&conn->cache_link)) {
462 list_del_init(&conn->cache_link);
463 rxrpc_put_connection(conn, rxrpc_conn_put_unidle);
464 }
465}
466
467/*
468 * Assign channels and callNumbers to waiting calls.
469 */
470static void rxrpc_activate_channels(struct rxrpc_bundle *bundle)
471{
472 struct rxrpc_connection *conn;
473 unsigned long avail, mask;
474 unsigned int channel, slot;
475
476 trace_rxrpc_client(NULL, -1, rxrpc_client_activate_chans);
477
478 if (bundle->try_upgrade)
479 mask = 1;
480 else
481 mask = ULONG_MAX;
482
483 while (!list_empty(&bundle->waiting_calls)) {
484 avail = bundle->avail_chans & mask;
485 if (!avail)
486 break;
487 channel = __ffs(avail);
488 clear_bit(channel, &bundle->avail_chans);
489
490 slot = channel / RXRPC_MAXCALLS;
491 conn = bundle->conns[slot];
492 if (!conn)
493 break;
494
495 if (bundle->try_upgrade)
496 set_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags);
497 rxrpc_unidle_conn(conn);
498
499 channel &= (RXRPC_MAXCALLS - 1);
500 conn->act_chans |= 1 << channel;
501 rxrpc_activate_one_channel(conn, channel);
502 }
503}
504
505/*
506 * Connect waiting channels (called from the I/O thread).
507 */
508void rxrpc_connect_client_calls(struct rxrpc_local *local)
509{
510 struct rxrpc_call *call;
511
512 while ((call = list_first_entry_or_null(&local->new_client_calls,
513 struct rxrpc_call, wait_link))
514 ) {
515 struct rxrpc_bundle *bundle = call->bundle;
516
517 spin_lock(&local->client_call_lock);
518 list_move_tail(&call->wait_link, &bundle->waiting_calls);
519 rxrpc_see_call(call, rxrpc_call_see_waiting_call);
520 spin_unlock(&local->client_call_lock);
521
522 if (rxrpc_bundle_has_space(bundle))
523 rxrpc_activate_channels(bundle);
524 }
525}
526
527/*
528 * Note that a call, and thus a connection, is about to be exposed to the
529 * world.
530 */
531void rxrpc_expose_client_call(struct rxrpc_call *call)
532{
533 unsigned int channel = call->cid & RXRPC_CHANNELMASK;
534 struct rxrpc_connection *conn = call->conn;
535 struct rxrpc_channel *chan = &conn->channels[channel];
536
537 if (!test_and_set_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
538 /* Mark the call ID as being used. If the callNumber counter
539 * exceeds ~2 billion, we kill the connection after its
540 * outstanding calls have finished so that the counter doesn't
541 * wrap.
542 */
543 chan->call_counter++;
544 if (chan->call_counter >= INT_MAX)
545 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
546 trace_rxrpc_client(conn, channel, rxrpc_client_exposed);
547
548 spin_lock(&call->peer->lock);
549 hlist_add_head(&call->error_link, &call->peer->error_targets);
550 spin_unlock(&call->peer->lock);
551 }
552}
553
554/*
555 * Set the reap timer.
556 */
557static void rxrpc_set_client_reap_timer(struct rxrpc_local *local)
558{
559 if (!local->kill_all_client_conns) {
560 unsigned long now = jiffies;
561 unsigned long reap_at = now + rxrpc_conn_idle_client_expiry;
562
563 if (local->rxnet->live)
564 timer_reduce(&local->client_conn_reap_timer, reap_at);
565 }
566}
567
568/*
569 * Disconnect a client call.
570 */
571void rxrpc_disconnect_client_call(struct rxrpc_bundle *bundle, struct rxrpc_call *call)
572{
573 struct rxrpc_connection *conn;
574 struct rxrpc_channel *chan = NULL;
575 struct rxrpc_local *local = bundle->local;
576 unsigned int channel;
577 bool may_reuse;
578 u32 cid;
579
580 _enter("c=%x", call->debug_id);
581
582 /* Calls that have never actually been assigned a channel can simply be
583 * discarded.
584 */
585 conn = call->conn;
586 if (!conn) {
587 _debug("call is waiting");
588 ASSERTCMP(call->call_id, ==, 0);
589 ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags));
590 /* May still be on ->new_client_calls. */
591 spin_lock(&local->client_call_lock);
592 list_del_init(&call->wait_link);
593 spin_unlock(&local->client_call_lock);
594 return;
595 }
596
597 cid = call->cid;
598 channel = cid & RXRPC_CHANNELMASK;
599 chan = &conn->channels[channel];
600 trace_rxrpc_client(conn, channel, rxrpc_client_chan_disconnect);
601
602 if (WARN_ON(chan->call != call))
603 return;
604
605 may_reuse = rxrpc_may_reuse_conn(conn);
606
607 /* If a client call was exposed to the world, we save the result for
608 * retransmission.
609 *
610 * We use a barrier here so that the call number and abort code can be
611 * read without needing to take a lock.
612 *
613 * TODO: Make the incoming packet handler check this and handle
614 * terminal retransmission without requiring access to the call.
615 */
616 if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
617 _debug("exposed %u,%u", call->call_id, call->abort_code);
618 __rxrpc_disconnect_call(conn, call);
619
620 if (test_and_clear_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags)) {
621 trace_rxrpc_client(conn, channel, rxrpc_client_to_active);
622 bundle->try_upgrade = false;
623 if (may_reuse)
624 rxrpc_activate_channels(bundle);
625 }
626 }
627
628 /* See if we can pass the channel directly to another call. */
629 if (may_reuse && !list_empty(&bundle->waiting_calls)) {
630 trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass);
631 rxrpc_activate_one_channel(conn, channel);
632 return;
633 }
634
635 /* Schedule the final ACK to be transmitted in a short while so that it
636 * can be skipped if we find a follow-on call. The first DATA packet
637 * of the follow on call will implicitly ACK this call.
638 */
639 if (call->completion == RXRPC_CALL_SUCCEEDED &&
640 test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
641 unsigned long final_ack_at = jiffies + 2;
642
643 chan->final_ack_at = final_ack_at;
644 smp_wmb(); /* vs rxrpc_process_delayed_final_acks() */
645 set_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags);
646 rxrpc_reduce_conn_timer(conn, final_ack_at);
647 }
648
649 /* Deactivate the channel. */
650 chan->call = NULL;
651 set_bit(conn->bundle_shift + channel, &conn->bundle->avail_chans);
652 conn->act_chans &= ~(1 << channel);
653
654 /* If no channels remain active, then put the connection on the idle
655 * list for a short while. Give it a ref to stop it going away if it
656 * becomes unbundled.
657 */
658 if (!conn->act_chans) {
659 trace_rxrpc_client(conn, channel, rxrpc_client_to_idle);
660 conn->idle_timestamp = jiffies;
661
662 rxrpc_get_connection(conn, rxrpc_conn_get_idle);
663 list_move_tail(&conn->cache_link, &local->idle_client_conns);
664
665 rxrpc_set_client_reap_timer(local);
666 }
667}
668
669/*
670 * Remove a connection from a bundle.
671 */
672static void rxrpc_unbundle_conn(struct rxrpc_connection *conn)
673{
674 struct rxrpc_bundle *bundle = conn->bundle;
675 unsigned int bindex;
676 int i;
677
678 _enter("C=%x", conn->debug_id);
679
680 if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
681 rxrpc_process_delayed_final_acks(conn, true);
682
683 bindex = conn->bundle_shift / RXRPC_MAXCALLS;
684 if (bundle->conns[bindex] == conn) {
685 _debug("clear slot %u", bindex);
686 bundle->conns[bindex] = NULL;
687 bundle->conn_ids[bindex] = 0;
688 for (i = 0; i < RXRPC_MAXCALLS; i++)
689 clear_bit(conn->bundle_shift + i, &bundle->avail_chans);
690 rxrpc_put_client_connection_id(bundle->local, conn);
691 rxrpc_deactivate_bundle(bundle);
692 rxrpc_put_connection(conn, rxrpc_conn_put_unbundle);
693 }
694}
695
696/*
697 * Drop the active count on a bundle.
698 */
699void rxrpc_deactivate_bundle(struct rxrpc_bundle *bundle)
700{
701 struct rxrpc_local *local;
702 bool need_put = false;
703
704 if (!bundle)
705 return;
706
707 local = bundle->local;
708 if (atomic_dec_and_lock(&bundle->active, &local->client_bundles_lock)) {
709 if (!bundle->exclusive) {
710 _debug("erase bundle");
711 rb_erase(&bundle->local_node, &local->client_bundles);
712 need_put = true;
713 }
714
715 spin_unlock(&local->client_bundles_lock);
716 if (need_put)
717 rxrpc_put_bundle(bundle, rxrpc_bundle_put_discard);
718 }
719}
720
721/*
722 * Clean up a dead client connection.
723 */
724void rxrpc_kill_client_conn(struct rxrpc_connection *conn)
725{
726 struct rxrpc_local *local = conn->local;
727 struct rxrpc_net *rxnet = local->rxnet;
728
729 _enter("C=%x", conn->debug_id);
730
731 trace_rxrpc_client(conn, -1, rxrpc_client_cleanup);
732 atomic_dec(&rxnet->nr_client_conns);
733
734 rxrpc_put_client_connection_id(local, conn);
735}
736
737/*
738 * Discard expired client connections from the idle list. Each conn in the
739 * idle list has been exposed and holds an extra ref because of that.
740 *
741 * This may be called from conn setup or from a work item so cannot be
742 * considered non-reentrant.
743 */
744void rxrpc_discard_expired_client_conns(struct rxrpc_local *local)
745{
746 struct rxrpc_connection *conn;
747 unsigned long expiry, conn_expires_at, now;
748 unsigned int nr_conns;
749
750 _enter("");
751
752 /* We keep an estimate of what the number of conns ought to be after
753 * we've discarded some so that we don't overdo the discarding.
754 */
755 nr_conns = atomic_read(&local->rxnet->nr_client_conns);
756
757next:
758 conn = list_first_entry_or_null(&local->idle_client_conns,
759 struct rxrpc_connection, cache_link);
760 if (!conn)
761 return;
762
763 if (!local->kill_all_client_conns) {
764 /* If the number of connections is over the reap limit, we
765 * expedite discard by reducing the expiry timeout. We must,
766 * however, have at least a short grace period to be able to do
767 * final-ACK or ABORT retransmission.
768 */
769 expiry = rxrpc_conn_idle_client_expiry;
770 if (nr_conns > rxrpc_reap_client_connections)
771 expiry = rxrpc_conn_idle_client_fast_expiry;
772 if (conn->local->service_closed)
773 expiry = rxrpc_closed_conn_expiry * HZ;
774
775 conn_expires_at = conn->idle_timestamp + expiry;
776
777 now = jiffies;
778 if (time_after(conn_expires_at, now))
779 goto not_yet_expired;
780 }
781
782 atomic_dec(&conn->active);
783 trace_rxrpc_client(conn, -1, rxrpc_client_discard);
784 list_del_init(&conn->cache_link);
785
786 rxrpc_unbundle_conn(conn);
787 /* Drop the ->cache_link ref */
788 rxrpc_put_connection(conn, rxrpc_conn_put_discard_idle);
789
790 nr_conns--;
791 goto next;
792
793not_yet_expired:
794 /* The connection at the front of the queue hasn't yet expired, so
795 * schedule the work item for that point if we discarded something.
796 *
797 * We don't worry if the work item is already scheduled - it can look
798 * after rescheduling itself at a later time. We could cancel it, but
799 * then things get messier.
800 */
801 _debug("not yet");
802 if (!local->kill_all_client_conns)
803 timer_reduce(&local->client_conn_reap_timer, conn_expires_at);
804
805 _leave("");
806}
807
808/*
809 * Clean up the client connections on a local endpoint.
810 */
811void rxrpc_clean_up_local_conns(struct rxrpc_local *local)
812{
813 struct rxrpc_connection *conn;
814
815 _enter("");
816
817 local->kill_all_client_conns = true;
818
819 del_timer_sync(&local->client_conn_reap_timer);
820
821 while ((conn = list_first_entry_or_null(&local->idle_client_conns,
822 struct rxrpc_connection, cache_link))) {
823 list_del_init(&conn->cache_link);
824 atomic_dec(&conn->active);
825 trace_rxrpc_client(conn, -1, rxrpc_client_discard);
826 rxrpc_unbundle_conn(conn);
827 rxrpc_put_connection(conn, rxrpc_conn_put_local_dead);
828 }
829
830 _leave(" [culled]");
831}