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_destroy_connection(struct rcu_head *);
23
rxrpc_connection_timer(struct timer_list * timer)24 static void rxrpc_connection_timer(struct timer_list *timer)
25 {
26 struct rxrpc_connection *conn =
27 container_of(timer, struct rxrpc_connection, timer);
28
29 rxrpc_queue_conn(conn);
30 }
31
32 /*
33 * allocate a new connection
34 */
rxrpc_alloc_connection(gfp_t gfp)35 struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
36 {
37 struct rxrpc_connection *conn;
38
39 _enter("");
40
41 conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
42 if (conn) {
43 INIT_LIST_HEAD(&conn->cache_link);
44 spin_lock_init(&conn->channel_lock);
45 INIT_LIST_HEAD(&conn->waiting_calls);
46 timer_setup(&conn->timer, &rxrpc_connection_timer, 0);
47 INIT_WORK(&conn->processor, &rxrpc_process_connection);
48 INIT_LIST_HEAD(&conn->proc_link);
49 INIT_LIST_HEAD(&conn->link);
50 skb_queue_head_init(&conn->rx_queue);
51 conn->security = &rxrpc_no_security;
52 spin_lock_init(&conn->state_lock);
53 conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
54 conn->size_align = 4;
55 conn->idle_timestamp = jiffies;
56 }
57
58 _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
59 return conn;
60 }
61
62 /*
63 * Look up a connection in the cache by protocol parameters.
64 *
65 * If successful, a pointer to the connection is returned, but no ref is taken.
66 * NULL is returned if there is no match.
67 *
68 * When searching for a service call, if we find a peer but no connection, we
69 * return that through *_peer in case we need to create a new service call.
70 *
71 * The caller must be holding the RCU read lock.
72 */
rxrpc_find_connection_rcu(struct rxrpc_local * local,struct sk_buff * skb,struct rxrpc_peer ** _peer)73 struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
74 struct sk_buff *skb,
75 struct rxrpc_peer **_peer)
76 {
77 struct rxrpc_connection *conn;
78 struct rxrpc_conn_proto k;
79 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
80 struct sockaddr_rxrpc srx;
81 struct rxrpc_peer *peer;
82
83 _enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);
84
85 if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
86 goto not_found;
87
88 if (srx.transport.family != local->srx.transport.family &&
89 (srx.transport.family == AF_INET &&
90 local->srx.transport.family != AF_INET6)) {
91 pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
92 srx.transport.family,
93 local->srx.transport.family);
94 goto not_found;
95 }
96
97 k.epoch = sp->hdr.epoch;
98 k.cid = sp->hdr.cid & RXRPC_CIDMASK;
99
100 if (rxrpc_to_server(sp)) {
101 /* We need to look up service connections by the full protocol
102 * parameter set. We look up the peer first as an intermediate
103 * step and then the connection from the peer's tree.
104 */
105 peer = rxrpc_lookup_peer_rcu(local, &srx);
106 if (!peer)
107 goto not_found;
108 *_peer = peer;
109 conn = rxrpc_find_service_conn_rcu(peer, skb);
110 if (!conn || atomic_read(&conn->usage) == 0)
111 goto not_found;
112 _leave(" = %p", conn);
113 return conn;
114 } else {
115 /* Look up client connections by connection ID alone as their
116 * IDs are unique for this machine.
117 */
118 conn = idr_find(&rxrpc_client_conn_ids,
119 sp->hdr.cid >> RXRPC_CIDSHIFT);
120 if (!conn || atomic_read(&conn->usage) == 0) {
121 _debug("no conn");
122 goto not_found;
123 }
124
125 if (conn->proto.epoch != k.epoch ||
126 conn->params.local != local)
127 goto not_found;
128
129 peer = conn->params.peer;
130 switch (srx.transport.family) {
131 case AF_INET:
132 if (peer->srx.transport.sin.sin_port !=
133 srx.transport.sin.sin_port ||
134 peer->srx.transport.sin.sin_addr.s_addr !=
135 srx.transport.sin.sin_addr.s_addr)
136 goto not_found;
137 break;
138 #ifdef CONFIG_AF_RXRPC_IPV6
139 case AF_INET6:
140 if (peer->srx.transport.sin6.sin6_port !=
141 srx.transport.sin6.sin6_port ||
142 memcmp(&peer->srx.transport.sin6.sin6_addr,
143 &srx.transport.sin6.sin6_addr,
144 sizeof(struct in6_addr)) != 0)
145 goto not_found;
146 break;
147 #endif
148 default:
149 BUG();
150 }
151
152 _leave(" = %p", conn);
153 return conn;
154 }
155
156 not_found:
157 _leave(" = NULL");
158 return NULL;
159 }
160
161 /*
162 * Disconnect a call and clear any channel it occupies when that call
163 * terminates. The caller must hold the channel_lock and must release the
164 * call's ref on the connection.
165 */
__rxrpc_disconnect_call(struct rxrpc_connection * conn,struct rxrpc_call * call)166 void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
167 struct rxrpc_call *call)
168 {
169 struct rxrpc_channel *chan =
170 &conn->channels[call->cid & RXRPC_CHANNELMASK];
171
172 _enter("%d,%x", conn->debug_id, call->cid);
173
174 if (rcu_access_pointer(chan->call) == call) {
175 /* Save the result of the call so that we can repeat it if necessary
176 * through the channel, whilst disposing of the actual call record.
177 */
178 trace_rxrpc_disconnect_call(call);
179 switch (call->completion) {
180 case RXRPC_CALL_SUCCEEDED:
181 chan->last_seq = call->rx_hard_ack;
182 chan->last_type = RXRPC_PACKET_TYPE_ACK;
183 break;
184 case RXRPC_CALL_LOCALLY_ABORTED:
185 chan->last_abort = call->abort_code;
186 chan->last_type = RXRPC_PACKET_TYPE_ABORT;
187 break;
188 default:
189 chan->last_abort = RX_USER_ABORT;
190 chan->last_type = RXRPC_PACKET_TYPE_ABORT;
191 break;
192 }
193
194 /* Sync with rxrpc_conn_retransmit(). */
195 smp_wmb();
196 chan->last_call = chan->call_id;
197 chan->call_id = chan->call_counter;
198
199 rcu_assign_pointer(chan->call, NULL);
200 }
201
202 _leave("");
203 }
204
205 /*
206 * Disconnect a call and clear any channel it occupies when that call
207 * terminates.
208 */
rxrpc_disconnect_call(struct rxrpc_call * call)209 void rxrpc_disconnect_call(struct rxrpc_call *call)
210 {
211 struct rxrpc_connection *conn = call->conn;
212
213 call->peer->cong_cwnd = call->cong_cwnd;
214
215 if (!hlist_unhashed(&call->error_link)) {
216 spin_lock_bh(&call->peer->lock);
217 hlist_del_rcu(&call->error_link);
218 spin_unlock_bh(&call->peer->lock);
219 }
220
221 if (rxrpc_is_client_call(call))
222 return rxrpc_disconnect_client_call(call);
223
224 spin_lock(&conn->channel_lock);
225 __rxrpc_disconnect_call(conn, call);
226 spin_unlock(&conn->channel_lock);
227
228 set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
229 conn->idle_timestamp = jiffies;
230 }
231
232 /*
233 * Kill off a connection.
234 */
rxrpc_kill_connection(struct rxrpc_connection * conn)235 void rxrpc_kill_connection(struct rxrpc_connection *conn)
236 {
237 struct rxrpc_net *rxnet = conn->params.local->rxnet;
238
239 ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
240 !rcu_access_pointer(conn->channels[1].call) &&
241 !rcu_access_pointer(conn->channels[2].call) &&
242 !rcu_access_pointer(conn->channels[3].call));
243 ASSERT(list_empty(&conn->cache_link));
244
245 write_lock(&rxnet->conn_lock);
246 list_del_init(&conn->proc_link);
247 write_unlock(&rxnet->conn_lock);
248
249 /* Drain the Rx queue. Note that even though we've unpublished, an
250 * incoming packet could still be being added to our Rx queue, so we
251 * will need to drain it again in the RCU cleanup handler.
252 */
253 rxrpc_purge_queue(&conn->rx_queue);
254
255 /* Leave final destruction to RCU. The connection processor work item
256 * must carry a ref on the connection to prevent us getting here whilst
257 * it is queued or running.
258 */
259 call_rcu(&conn->rcu, rxrpc_destroy_connection);
260 }
261
262 /*
263 * Queue a connection's work processor, getting a ref to pass to the work
264 * queue.
265 */
rxrpc_queue_conn(struct rxrpc_connection * conn)266 bool rxrpc_queue_conn(struct rxrpc_connection *conn)
267 {
268 const void *here = __builtin_return_address(0);
269 int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
270 if (n == 0)
271 return false;
272 if (rxrpc_queue_work(&conn->processor))
273 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_queued, n + 1, here);
274 else
275 rxrpc_put_connection(conn);
276 return true;
277 }
278
279 /*
280 * Note the re-emergence of a connection.
281 */
rxrpc_see_connection(struct rxrpc_connection * conn)282 void rxrpc_see_connection(struct rxrpc_connection *conn)
283 {
284 const void *here = __builtin_return_address(0);
285 if (conn) {
286 int n = atomic_read(&conn->usage);
287
288 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_seen, n, here);
289 }
290 }
291
292 /*
293 * Get a ref on a connection.
294 */
rxrpc_get_connection(struct rxrpc_connection * conn)295 void rxrpc_get_connection(struct rxrpc_connection *conn)
296 {
297 const void *here = __builtin_return_address(0);
298 int n = atomic_inc_return(&conn->usage);
299
300 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n, here);
301 }
302
303 /*
304 * Try to get a ref on a connection.
305 */
306 struct rxrpc_connection *
rxrpc_get_connection_maybe(struct rxrpc_connection * conn)307 rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
308 {
309 const void *here = __builtin_return_address(0);
310
311 if (conn) {
312 int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
313 if (n > 0)
314 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n + 1, here);
315 else
316 conn = NULL;
317 }
318 return conn;
319 }
320
321 /*
322 * Set the service connection reap timer.
323 */
rxrpc_set_service_reap_timer(struct rxrpc_net * rxnet,unsigned long reap_at)324 static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
325 unsigned long reap_at)
326 {
327 if (rxnet->live)
328 timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
329 }
330
331 /*
332 * Release a service connection
333 */
rxrpc_put_service_conn(struct rxrpc_connection * conn)334 void rxrpc_put_service_conn(struct rxrpc_connection *conn)
335 {
336 const void *here = __builtin_return_address(0);
337 unsigned int debug_id = conn->debug_id;
338 int n;
339
340 n = atomic_dec_return(&conn->usage);
341 trace_rxrpc_conn(debug_id, rxrpc_conn_put_service, n, here);
342 ASSERTCMP(n, >=, 0);
343 if (n == 1)
344 rxrpc_set_service_reap_timer(conn->params.local->rxnet,
345 jiffies + rxrpc_connection_expiry);
346 }
347
348 /*
349 * destroy a virtual connection
350 */
rxrpc_destroy_connection(struct rcu_head * rcu)351 static void rxrpc_destroy_connection(struct rcu_head *rcu)
352 {
353 struct rxrpc_connection *conn =
354 container_of(rcu, struct rxrpc_connection, rcu);
355
356 _enter("{%d,u=%d}", conn->debug_id, atomic_read(&conn->usage));
357
358 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
359
360 _net("DESTROY CONN %d", conn->debug_id);
361
362 del_timer_sync(&conn->timer);
363 rxrpc_purge_queue(&conn->rx_queue);
364
365 conn->security->clear(conn);
366 key_put(conn->params.key);
367 key_put(conn->server_key);
368 rxrpc_put_peer(conn->params.peer);
369
370 if (atomic_dec_and_test(&conn->params.local->rxnet->nr_conns))
371 wake_up_var(&conn->params.local->rxnet->nr_conns);
372 rxrpc_put_local(conn->params.local);
373
374 kfree(conn);
375 _leave("");
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
388 LIST_HEAD(graveyard);
389
390 _enter("");
391
392 now = jiffies;
393 earliest = now + MAX_JIFFY_OFFSET;
394
395 write_lock(&rxnet->conn_lock);
396 list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
397 ASSERTCMP(atomic_read(&conn->usage), >, 0);
398 if (likely(atomic_read(&conn->usage) > 1))
399 continue;
400 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
401 continue;
402
403 if (rxnet->live && !conn->params.local->dead) {
404 idle_timestamp = READ_ONCE(conn->idle_timestamp);
405 expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
406 if (conn->params.local->service_closed)
407 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
408
409 _debug("reap CONN %d { u=%d,t=%ld }",
410 conn->debug_id, atomic_read(&conn->usage),
411 (long)expire_at - (long)now);
412
413 if (time_before(now, expire_at)) {
414 if (time_before(expire_at, earliest))
415 earliest = expire_at;
416 continue;
417 }
418 }
419
420 /* The usage count sits at 1 whilst the object is unused on the
421 * list; we reduce that to 0 to make the object unavailable.
422 */
423 if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
424 continue;
425 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_reap_service, 0, NULL);
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->usage), ==, 0);
448 rxrpc_kill_connection(conn);
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 */
rxrpc_destroy_all_connections(struct rxrpc_net * rxnet)458 void 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 rxrpc_destroy_all_client_connections(rxnet);
467
468 del_timer_sync(&rxnet->service_conn_reap_timer);
469 rxrpc_queue_work(&rxnet->service_conn_reaper);
470 flush_workqueue(rxrpc_workqueue);
471
472 write_lock(&rxnet->conn_lock);
473 list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
474 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
475 conn, atomic_read(&conn->usage));
476 leak = true;
477 }
478 write_unlock(&rxnet->conn_lock);
479 BUG_ON(leak);
480
481 ASSERT(list_empty(&rxnet->conn_proc_list));
482
483 /* We need to wait for the connections to be destroyed by RCU as they
484 * pin things that we still need to get rid of.
485 */
486 wait_var_event(&rxnet->nr_conns, !atomic_read(&rxnet->nr_conns));
487 _leave("");
488 }
489