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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* RxRPC virtual connection handler, common bits.
3 *
4 * Copyright (C) 2007, 2016 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 <linux/module.h>
11#include <linux/slab.h>
12#include <linux/net.h>
13#include <linux/skbuff.h>
14#include "ar-internal.h"
15
16/*
17 * Time till a connection expires after last use (in seconds).
18 */
19unsigned int __read_mostly rxrpc_connection_expiry = 10 * 60;
20unsigned int __read_mostly rxrpc_closed_conn_expiry = 10;
21
22static void rxrpc_clean_up_connection(struct work_struct *work);
23static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
24 unsigned long reap_at);
25
26void rxrpc_poke_conn(struct rxrpc_connection *conn, enum rxrpc_conn_trace why)
27{
28 struct rxrpc_local *local = conn->local;
29 bool busy;
30
31 if (WARN_ON_ONCE(!local))
32 return;
33
34 spin_lock_bh(&local->lock);
35 busy = !list_empty(&conn->attend_link);
36 if (!busy) {
37 rxrpc_get_connection(conn, why);
38 list_add_tail(&conn->attend_link, &local->conn_attend_q);
39 }
40 spin_unlock_bh(&local->lock);
41 rxrpc_wake_up_io_thread(local);
42}
43
44static void rxrpc_connection_timer(struct timer_list *timer)
45{
46 struct rxrpc_connection *conn =
47 container_of(timer, struct rxrpc_connection, timer);
48
49 rxrpc_poke_conn(conn, rxrpc_conn_get_poke_timer);
50}
51
52/*
53 * allocate a new connection
54 */
55struct rxrpc_connection *rxrpc_alloc_connection(struct rxrpc_net *rxnet,
56 gfp_t gfp)
57{
58 struct rxrpc_connection *conn;
59
60 _enter("");
61
62 conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
63 if (conn) {
64 INIT_LIST_HEAD(&conn->cache_link);
65 timer_setup(&conn->timer, &rxrpc_connection_timer, 0);
66 INIT_WORK(&conn->processor, rxrpc_process_connection);
67 INIT_WORK(&conn->destructor, rxrpc_clean_up_connection);
68 INIT_LIST_HEAD(&conn->proc_link);
69 INIT_LIST_HEAD(&conn->link);
70 INIT_LIST_HEAD(&conn->attend_link);
71 mutex_init(&conn->security_lock);
72 mutex_init(&conn->tx_data_alloc_lock);
73 skb_queue_head_init(&conn->rx_queue);
74 conn->rxnet = rxnet;
75 conn->security = &rxrpc_no_security;
76 spin_lock_init(&conn->state_lock);
77 conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
78 conn->idle_timestamp = jiffies;
79 }
80
81 _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
82 return conn;
83}
84
85/*
86 * Look up a connection in the cache by protocol parameters.
87 *
88 * If successful, a pointer to the connection is returned, but no ref is taken.
89 * NULL is returned if there is no match.
90 *
91 * When searching for a service call, if we find a peer but no connection, we
92 * return that through *_peer in case we need to create a new service call.
93 *
94 * The caller must be holding the RCU read lock.
95 */
96struct rxrpc_connection *rxrpc_find_client_connection_rcu(struct rxrpc_local *local,
97 struct sockaddr_rxrpc *srx,
98 struct sk_buff *skb)
99{
100 struct rxrpc_connection *conn;
101 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
102 struct rxrpc_peer *peer;
103
104 _enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);
105
106 /* Look up client connections by connection ID alone as their
107 * IDs are unique for this machine.
108 */
109 conn = idr_find(&local->conn_ids, sp->hdr.cid >> RXRPC_CIDSHIFT);
110 if (!conn || refcount_read(&conn->ref) == 0) {
111 _debug("no conn");
112 goto not_found;
113 }
114
115 if (conn->proto.epoch != sp->hdr.epoch ||
116 conn->local != local)
117 goto not_found;
118
119 peer = conn->peer;
120 switch (srx->transport.family) {
121 case AF_INET:
122 if (peer->srx.transport.sin.sin_port !=
123 srx->transport.sin.sin_port)
124 goto not_found;
125 break;
126#ifdef CONFIG_AF_RXRPC_IPV6
127 case AF_INET6:
128 if (peer->srx.transport.sin6.sin6_port !=
129 srx->transport.sin6.sin6_port)
130 goto not_found;
131 break;
132#endif
133 default:
134 BUG();
135 }
136
137 _leave(" = %p", conn);
138 return conn;
139
140not_found:
141 _leave(" = NULL");
142 return NULL;
143}
144
145/*
146 * Disconnect a call and clear any channel it occupies when that call
147 * terminates. The caller must hold the channel_lock and must release the
148 * call's ref on the connection.
149 */
150void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
151 struct rxrpc_call *call)
152{
153 struct rxrpc_channel *chan =
154 &conn->channels[call->cid & RXRPC_CHANNELMASK];
155
156 _enter("%d,%x", conn->debug_id, call->cid);
157
158 if (chan->call == call) {
159 /* Save the result of the call so that we can repeat it if necessary
160 * through the channel, whilst disposing of the actual call record.
161 */
162 trace_rxrpc_disconnect_call(call);
163 switch (call->completion) {
164 case RXRPC_CALL_SUCCEEDED:
165 chan->last_seq = call->rx_highest_seq;
166 chan->last_type = RXRPC_PACKET_TYPE_ACK;
167 break;
168 case RXRPC_CALL_LOCALLY_ABORTED:
169 chan->last_abort = call->abort_code;
170 chan->last_type = RXRPC_PACKET_TYPE_ABORT;
171 break;
172 default:
173 chan->last_abort = RX_CALL_DEAD;
174 chan->last_type = RXRPC_PACKET_TYPE_ABORT;
175 break;
176 }
177
178 chan->last_call = chan->call_id;
179 chan->call_id = chan->call_counter;
180 chan->call = NULL;
181 }
182
183 _leave("");
184}
185
186/*
187 * Disconnect a call and clear any channel it occupies when that call
188 * terminates.
189 */
190void rxrpc_disconnect_call(struct rxrpc_call *call)
191{
192 struct rxrpc_connection *conn = call->conn;
193
194 set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
195 rxrpc_see_call(call, rxrpc_call_see_disconnected);
196
197 call->peer->cong_ssthresh = call->cong_ssthresh;
198
199 if (!hlist_unhashed(&call->error_link)) {
200 spin_lock(&call->peer->lock);
201 hlist_del_init(&call->error_link);
202 spin_unlock(&call->peer->lock);
203 }
204
205 if (rxrpc_is_client_call(call)) {
206 rxrpc_disconnect_client_call(call->bundle, call);
207 } else {
208 __rxrpc_disconnect_call(conn, call);
209 conn->idle_timestamp = jiffies;
210 if (atomic_dec_and_test(&conn->active))
211 rxrpc_set_service_reap_timer(conn->rxnet,
212 jiffies + rxrpc_connection_expiry * HZ);
213 }
214
215 rxrpc_put_call(call, rxrpc_call_put_io_thread);
216}
217
218/*
219 * Queue a connection's work processor, getting a ref to pass to the work
220 * queue.
221 */
222void rxrpc_queue_conn(struct rxrpc_connection *conn, enum rxrpc_conn_trace why)
223{
224 if (atomic_read(&conn->active) >= 0 &&
225 rxrpc_queue_work(&conn->processor))
226 rxrpc_see_connection(conn, why);
227}
228
229/*
230 * Note the re-emergence of a connection.
231 */
232void rxrpc_see_connection(struct rxrpc_connection *conn,
233 enum rxrpc_conn_trace why)
234{
235 if (conn) {
236 int r = refcount_read(&conn->ref);
237
238 trace_rxrpc_conn(conn->debug_id, r, why);
239 }
240}
241
242/*
243 * Get a ref on a connection.
244 */
245struct rxrpc_connection *rxrpc_get_connection(struct rxrpc_connection *conn,
246 enum rxrpc_conn_trace why)
247{
248 int r;
249
250 __refcount_inc(&conn->ref, &r);
251 trace_rxrpc_conn(conn->debug_id, r + 1, why);
252 return conn;
253}
254
255/*
256 * Try to get a ref on a connection.
257 */
258struct rxrpc_connection *
259rxrpc_get_connection_maybe(struct rxrpc_connection *conn,
260 enum rxrpc_conn_trace why)
261{
262 int r;
263
264 if (conn) {
265 if (__refcount_inc_not_zero(&conn->ref, &r))
266 trace_rxrpc_conn(conn->debug_id, r + 1, why);
267 else
268 conn = NULL;
269 }
270 return conn;
271}
272
273/*
274 * Set the service connection reap timer.
275 */
276static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
277 unsigned long reap_at)
278{
279 if (rxnet->live)
280 timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
281}
282
283/*
284 * destroy a virtual connection
285 */
286static void rxrpc_rcu_free_connection(struct rcu_head *rcu)
287{
288 struct rxrpc_connection *conn =
289 container_of(rcu, struct rxrpc_connection, rcu);
290 struct rxrpc_net *rxnet = conn->rxnet;
291
292 _enter("{%d,u=%d}", conn->debug_id, refcount_read(&conn->ref));
293
294 trace_rxrpc_conn(conn->debug_id, refcount_read(&conn->ref),
295 rxrpc_conn_free);
296 kfree(conn);
297
298 if (atomic_dec_and_test(&rxnet->nr_conns))
299 wake_up_var(&rxnet->nr_conns);
300}
301
302/*
303 * Clean up a dead connection.
304 */
305static void rxrpc_clean_up_connection(struct work_struct *work)
306{
307 struct rxrpc_connection *conn =
308 container_of(work, struct rxrpc_connection, destructor);
309 struct rxrpc_net *rxnet = conn->rxnet;
310
311 ASSERT(!conn->channels[0].call &&
312 !conn->channels[1].call &&
313 !conn->channels[2].call &&
314 !conn->channels[3].call);
315 ASSERT(list_empty(&conn->cache_link));
316
317 del_timer_sync(&conn->timer);
318 cancel_work_sync(&conn->processor); /* Processing may restart the timer */
319 del_timer_sync(&conn->timer);
320
321 write_lock(&rxnet->conn_lock);
322 list_del_init(&conn->proc_link);
323 write_unlock(&rxnet->conn_lock);
324
325 rxrpc_purge_queue(&conn->rx_queue);
326
327 rxrpc_kill_client_conn(conn);
328
329 conn->security->clear(conn);
330 key_put(conn->key);
331 rxrpc_put_bundle(conn->bundle, rxrpc_bundle_put_conn);
332 rxrpc_put_peer(conn->peer, rxrpc_peer_put_conn);
333 rxrpc_put_local(conn->local, rxrpc_local_put_kill_conn);
334
335 /* Drain the Rx queue. Note that even though we've unpublished, an
336 * incoming packet could still be being added to our Rx queue, so we
337 * will need to drain it again in the RCU cleanup handler.
338 */
339 rxrpc_purge_queue(&conn->rx_queue);
340
341 page_frag_cache_drain(&conn->tx_data_alloc);
342 call_rcu(&conn->rcu, rxrpc_rcu_free_connection);
343}
344
345/*
346 * Drop a ref on a connection.
347 */
348void rxrpc_put_connection(struct rxrpc_connection *conn,
349 enum rxrpc_conn_trace why)
350{
351 unsigned int debug_id;
352 bool dead;
353 int r;
354
355 if (!conn)
356 return;
357
358 debug_id = conn->debug_id;
359 dead = __refcount_dec_and_test(&conn->ref, &r);
360 trace_rxrpc_conn(debug_id, r - 1, why);
361 if (dead) {
362 del_timer(&conn->timer);
363 cancel_work(&conn->processor);
364
365 if (in_softirq() || work_busy(&conn->processor) ||
366 timer_pending(&conn->timer))
367 /* Can't use the rxrpc workqueue as we need to cancel/flush
368 * something that may be running/waiting there.
369 */
370 schedule_work(&conn->destructor);
371 else
372 rxrpc_clean_up_connection(&conn->destructor);
373 }
374}
375
376/*
377 * reap dead service connections
378 */
379void rxrpc_service_connection_reaper(struct work_struct *work)
380{
381 struct rxrpc_connection *conn, *_p;
382 struct rxrpc_net *rxnet =
383 container_of(work, struct rxrpc_net, service_conn_reaper);
384 unsigned long expire_at, earliest, idle_timestamp, now;
385 int active;
386
387 LIST_HEAD(graveyard);
388
389 _enter("");
390
391 now = jiffies;
392 earliest = now + MAX_JIFFY_OFFSET;
393
394 write_lock(&rxnet->conn_lock);
395 list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
396 ASSERTCMP(atomic_read(&conn->active), >=, 0);
397 if (likely(atomic_read(&conn->active) > 0))
398 continue;
399 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
400 continue;
401
402 if (rxnet->live && !conn->local->dead) {
403 idle_timestamp = READ_ONCE(conn->idle_timestamp);
404 expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
405 if (conn->local->service_closed)
406 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
407
408 _debug("reap CONN %d { a=%d,t=%ld }",
409 conn->debug_id, atomic_read(&conn->active),
410 (long)expire_at - (long)now);
411
412 if (time_before(now, expire_at)) {
413 if (time_before(expire_at, earliest))
414 earliest = expire_at;
415 continue;
416 }
417 }
418
419 /* The activity count sits at 0 whilst the conn is unused on
420 * the list; we reduce that to -1 to make the conn unavailable.
421 */
422 active = 0;
423 if (!atomic_try_cmpxchg(&conn->active, &active, -1))
424 continue;
425 rxrpc_see_connection(conn, rxrpc_conn_see_reap_service);
426
427 if (rxrpc_conn_is_client(conn))
428 BUG();
429 else
430 rxrpc_unpublish_service_conn(conn);
431
432 list_move_tail(&conn->link, &graveyard);
433 }
434 write_unlock(&rxnet->conn_lock);
435
436 if (earliest != now + MAX_JIFFY_OFFSET) {
437 _debug("reschedule reaper %ld", (long)earliest - (long)now);
438 ASSERT(time_after(earliest, now));
439 rxrpc_set_service_reap_timer(rxnet, earliest);
440 }
441
442 while (!list_empty(&graveyard)) {
443 conn = list_entry(graveyard.next, struct rxrpc_connection,
444 link);
445 list_del_init(&conn->link);
446
447 ASSERTCMP(atomic_read(&conn->active), ==, -1);
448 rxrpc_put_connection(conn, rxrpc_conn_put_service_reaped);
449 }
450
451 _leave("");
452}
453
454/*
455 * preemptively destroy all the service connection records rather than
456 * waiting for them to time out
457 */
458void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
459{
460 struct rxrpc_connection *conn, *_p;
461 bool leak = false;
462
463 _enter("");
464
465 atomic_dec(&rxnet->nr_conns);
466
467 del_timer_sync(&rxnet->service_conn_reap_timer);
468 rxrpc_queue_work(&rxnet->service_conn_reaper);
469 flush_workqueue(rxrpc_workqueue);
470
471 write_lock(&rxnet->conn_lock);
472 list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
473 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
474 conn, refcount_read(&conn->ref));
475 leak = true;
476 }
477 write_unlock(&rxnet->conn_lock);
478 BUG_ON(leak);
479
480 ASSERT(list_empty(&rxnet->conn_proc_list));
481
482 /* We need to wait for the connections to be destroyed by RCU as they
483 * pin things that we still need to get rid of.
484 */
485 wait_var_event(&rxnet->nr_conns, !atomic_read(&rxnet->nr_conns));
486 _leave("");
487}