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 */
19 unsigned int __read_mostly rxrpc_connection_expiry = 10 * 60;
20 unsigned int __read_mostly rxrpc_closed_conn_expiry = 10;
21
22 static void rxrpc_clean_up_connection(struct work_struct *work);
23 static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
24 unsigned long reap_at);
25
rxrpc_poke_conn(struct rxrpc_connection * conn,enum rxrpc_conn_trace why)26 void 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
rxrpc_connection_timer(struct timer_list * timer)44 static 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 */
rxrpc_alloc_connection(struct rxrpc_net * rxnet,gfp_t gfp)55 struct 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 */
rxrpc_find_client_connection_rcu(struct rxrpc_local * local,struct sockaddr_rxrpc * srx,struct sk_buff * skb)96 struct 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
140 not_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 */
__rxrpc_disconnect_call(struct rxrpc_connection * conn,struct rxrpc_call * call)150 void __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 */
rxrpc_disconnect_call(struct rxrpc_call * call)190 void 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 */
rxrpc_queue_conn(struct rxrpc_connection * conn,enum rxrpc_conn_trace why)222 void 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 */
rxrpc_see_connection(struct rxrpc_connection * conn,enum rxrpc_conn_trace why)232 void 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 */
rxrpc_get_connection(struct rxrpc_connection * conn,enum rxrpc_conn_trace why)245 struct 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 */
258 struct rxrpc_connection *
rxrpc_get_connection_maybe(struct rxrpc_connection * conn,enum rxrpc_conn_trace why)259 rxrpc_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 */
rxrpc_set_service_reap_timer(struct rxrpc_net * rxnet,unsigned long reap_at)276 static 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 */
rxrpc_rcu_free_connection(struct rcu_head * rcu)286 static 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 */
rxrpc_clean_up_connection(struct work_struct * work)305 static 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 if (conn->tx_data_alloc.va)
342 __page_frag_cache_drain(virt_to_page(conn->tx_data_alloc.va),
343 conn->tx_data_alloc.pagecnt_bias);
344 call_rcu(&conn->rcu, rxrpc_rcu_free_connection);
345 }
346
347 /*
348 * Drop a ref on a connection.
349 */
rxrpc_put_connection(struct rxrpc_connection * conn,enum rxrpc_conn_trace why)350 void rxrpc_put_connection(struct rxrpc_connection *conn,
351 enum rxrpc_conn_trace why)
352 {
353 unsigned int debug_id;
354 bool dead;
355 int r;
356
357 if (!conn)
358 return;
359
360 debug_id = conn->debug_id;
361 dead = __refcount_dec_and_test(&conn->ref, &r);
362 trace_rxrpc_conn(debug_id, r - 1, why);
363 if (dead) {
364 del_timer(&conn->timer);
365 cancel_work(&conn->processor);
366
367 if (in_softirq() || work_busy(&conn->processor) ||
368 timer_pending(&conn->timer))
369 /* Can't use the rxrpc workqueue as we need to cancel/flush
370 * something that may be running/waiting there.
371 */
372 schedule_work(&conn->destructor);
373 else
374 rxrpc_clean_up_connection(&conn->destructor);
375 }
376 }
377
378 /*
379 * reap dead service connections
380 */
rxrpc_service_connection_reaper(struct work_struct * work)381 void rxrpc_service_connection_reaper(struct work_struct *work)
382 {
383 struct rxrpc_connection *conn, *_p;
384 struct rxrpc_net *rxnet =
385 container_of(work, struct rxrpc_net, service_conn_reaper);
386 unsigned long expire_at, earliest, idle_timestamp, now;
387 int active;
388
389 LIST_HEAD(graveyard);
390
391 _enter("");
392
393 now = jiffies;
394 earliest = now + MAX_JIFFY_OFFSET;
395
396 write_lock(&rxnet->conn_lock);
397 list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
398 ASSERTCMP(atomic_read(&conn->active), >=, 0);
399 if (likely(atomic_read(&conn->active) > 0))
400 continue;
401 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
402 continue;
403
404 if (rxnet->live && !conn->local->dead) {
405 idle_timestamp = READ_ONCE(conn->idle_timestamp);
406 expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
407 if (conn->local->service_closed)
408 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
409
410 _debug("reap CONN %d { a=%d,t=%ld }",
411 conn->debug_id, atomic_read(&conn->active),
412 (long)expire_at - (long)now);
413
414 if (time_before(now, expire_at)) {
415 if (time_before(expire_at, earliest))
416 earliest = expire_at;
417 continue;
418 }
419 }
420
421 /* The activity count sits at 0 whilst the conn is unused on
422 * the list; we reduce that to -1 to make the conn unavailable.
423 */
424 active = 0;
425 if (!atomic_try_cmpxchg(&conn->active, &active, -1))
426 continue;
427 rxrpc_see_connection(conn, rxrpc_conn_see_reap_service);
428
429 if (rxrpc_conn_is_client(conn))
430 BUG();
431 else
432 rxrpc_unpublish_service_conn(conn);
433
434 list_move_tail(&conn->link, &graveyard);
435 }
436 write_unlock(&rxnet->conn_lock);
437
438 if (earliest != now + MAX_JIFFY_OFFSET) {
439 _debug("reschedule reaper %ld", (long)earliest - (long)now);
440 ASSERT(time_after(earliest, now));
441 rxrpc_set_service_reap_timer(rxnet, earliest);
442 }
443
444 while (!list_empty(&graveyard)) {
445 conn = list_entry(graveyard.next, struct rxrpc_connection,
446 link);
447 list_del_init(&conn->link);
448
449 ASSERTCMP(atomic_read(&conn->active), ==, -1);
450 rxrpc_put_connection(conn, rxrpc_conn_put_service_reaped);
451 }
452
453 _leave("");
454 }
455
456 /*
457 * preemptively destroy all the service connection records rather than
458 * waiting for them to time out
459 */
rxrpc_destroy_all_connections(struct rxrpc_net * rxnet)460 void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
461 {
462 struct rxrpc_connection *conn, *_p;
463 bool leak = false;
464
465 _enter("");
466
467 atomic_dec(&rxnet->nr_conns);
468
469 del_timer_sync(&rxnet->service_conn_reap_timer);
470 rxrpc_queue_work(&rxnet->service_conn_reaper);
471 flush_workqueue(rxrpc_workqueue);
472
473 write_lock(&rxnet->conn_lock);
474 list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
475 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
476 conn, refcount_read(&conn->ref));
477 leak = true;
478 }
479 write_unlock(&rxnet->conn_lock);
480 BUG_ON(leak);
481
482 ASSERT(list_empty(&rxnet->conn_proc_list));
483
484 /* We need to wait for the connections to be destroyed by RCU as they
485 * pin things that we still need to get rid of.
486 */
487 wait_var_event(&rxnet->nr_conns, !atomic_read(&rxnet->nr_conns));
488 _leave("");
489 }
490