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 spin_lock_bh(&conn->params.peer->lock);
216 hlist_del_rcu(&call->error_link);
217 spin_unlock_bh(&conn->params.peer->lock);
218
219 if (rxrpc_is_client_call(call))
220 return rxrpc_disconnect_client_call(call);
221
222 spin_lock(&conn->channel_lock);
223 __rxrpc_disconnect_call(conn, call);
224 spin_unlock(&conn->channel_lock);
225
226 call->conn = NULL;
227 conn->idle_timestamp = jiffies;
228 rxrpc_put_connection(conn);
229 }
230
231 /*
232 * Kill off a connection.
233 */
rxrpc_kill_connection(struct rxrpc_connection * conn)234 void rxrpc_kill_connection(struct rxrpc_connection *conn)
235 {
236 struct rxrpc_net *rxnet = conn->params.local->rxnet;
237
238 ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
239 !rcu_access_pointer(conn->channels[1].call) &&
240 !rcu_access_pointer(conn->channels[2].call) &&
241 !rcu_access_pointer(conn->channels[3].call));
242 ASSERT(list_empty(&conn->cache_link));
243
244 write_lock(&rxnet->conn_lock);
245 list_del_init(&conn->proc_link);
246 write_unlock(&rxnet->conn_lock);
247
248 /* Drain the Rx queue. Note that even though we've unpublished, an
249 * incoming packet could still be being added to our Rx queue, so we
250 * will need to drain it again in the RCU cleanup handler.
251 */
252 rxrpc_purge_queue(&conn->rx_queue);
253
254 /* Leave final destruction to RCU. The connection processor work item
255 * must carry a ref on the connection to prevent us getting here whilst
256 * it is queued or running.
257 */
258 call_rcu(&conn->rcu, rxrpc_destroy_connection);
259 }
260
261 /*
262 * Queue a connection's work processor, getting a ref to pass to the work
263 * queue.
264 */
rxrpc_queue_conn(struct rxrpc_connection * conn)265 bool rxrpc_queue_conn(struct rxrpc_connection *conn)
266 {
267 const void *here = __builtin_return_address(0);
268 int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
269 if (n == 0)
270 return false;
271 if (rxrpc_queue_work(&conn->processor))
272 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_queued, n + 1, here);
273 else
274 rxrpc_put_connection(conn);
275 return true;
276 }
277
278 /*
279 * Note the re-emergence of a connection.
280 */
rxrpc_see_connection(struct rxrpc_connection * conn)281 void rxrpc_see_connection(struct rxrpc_connection *conn)
282 {
283 const void *here = __builtin_return_address(0);
284 if (conn) {
285 int n = atomic_read(&conn->usage);
286
287 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_seen, n, here);
288 }
289 }
290
291 /*
292 * Get a ref on a connection.
293 */
rxrpc_get_connection(struct rxrpc_connection * conn)294 void rxrpc_get_connection(struct rxrpc_connection *conn)
295 {
296 const void *here = __builtin_return_address(0);
297 int n = atomic_inc_return(&conn->usage);
298
299 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n, here);
300 }
301
302 /*
303 * Try to get a ref on a connection.
304 */
305 struct rxrpc_connection *
rxrpc_get_connection_maybe(struct rxrpc_connection * conn)306 rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
307 {
308 const void *here = __builtin_return_address(0);
309
310 if (conn) {
311 int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
312 if (n > 0)
313 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n + 1, here);
314 else
315 conn = NULL;
316 }
317 return conn;
318 }
319
320 /*
321 * Set the service connection reap timer.
322 */
rxrpc_set_service_reap_timer(struct rxrpc_net * rxnet,unsigned long reap_at)323 static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
324 unsigned long reap_at)
325 {
326 if (rxnet->live)
327 timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
328 }
329
330 /*
331 * Release a service connection
332 */
rxrpc_put_service_conn(struct rxrpc_connection * conn)333 void rxrpc_put_service_conn(struct rxrpc_connection *conn)
334 {
335 const void *here = __builtin_return_address(0);
336 unsigned int debug_id = conn->debug_id;
337 int n;
338
339 n = atomic_dec_return(&conn->usage);
340 trace_rxrpc_conn(debug_id, rxrpc_conn_put_service, n, here);
341 ASSERTCMP(n, >=, 0);
342 if (n == 1)
343 rxrpc_set_service_reap_timer(conn->params.local->rxnet,
344 jiffies + rxrpc_connection_expiry);
345 }
346
347 /*
348 * destroy a virtual connection
349 */
rxrpc_destroy_connection(struct rcu_head * rcu)350 static void rxrpc_destroy_connection(struct rcu_head *rcu)
351 {
352 struct rxrpc_connection *conn =
353 container_of(rcu, struct rxrpc_connection, rcu);
354
355 _enter("{%d,u=%d}", conn->debug_id, atomic_read(&conn->usage));
356
357 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
358
359 _net("DESTROY CONN %d", conn->debug_id);
360
361 del_timer_sync(&conn->timer);
362 rxrpc_purge_queue(&conn->rx_queue);
363
364 conn->security->clear(conn);
365 key_put(conn->params.key);
366 key_put(conn->server_key);
367 rxrpc_put_peer(conn->params.peer);
368
369 if (atomic_dec_and_test(&conn->params.local->rxnet->nr_conns))
370 wake_up_var(&conn->params.local->rxnet->nr_conns);
371 rxrpc_put_local(conn->params.local);
372
373 kfree(conn);
374 _leave("");
375 }
376
377 /*
378 * reap dead service connections
379 */
rxrpc_service_connection_reaper(struct work_struct * work)380 void rxrpc_service_connection_reaper(struct work_struct *work)
381 {
382 struct rxrpc_connection *conn, *_p;
383 struct rxrpc_net *rxnet =
384 container_of(work, struct rxrpc_net, service_conn_reaper);
385 unsigned long expire_at, earliest, idle_timestamp, now;
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->usage), >, 0);
397 if (likely(atomic_read(&conn->usage) > 1))
398 continue;
399 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
400 continue;
401
402 if (rxnet->live && !conn->params.local->dead) {
403 idle_timestamp = READ_ONCE(conn->idle_timestamp);
404 expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
405 if (conn->params.local->service_closed)
406 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
407
408 _debug("reap CONN %d { u=%d,t=%ld }",
409 conn->debug_id, atomic_read(&conn->usage),
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 usage count sits at 1 whilst the object is unused on the
420 * list; we reduce that to 0 to make the object unavailable.
421 */
422 if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
423 continue;
424 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_reap_service, 0, NULL);
425
426 if (rxrpc_conn_is_client(conn))
427 BUG();
428 else
429 rxrpc_unpublish_service_conn(conn);
430
431 list_move_tail(&conn->link, &graveyard);
432 }
433 write_unlock(&rxnet->conn_lock);
434
435 if (earliest != now + MAX_JIFFY_OFFSET) {
436 _debug("reschedule reaper %ld", (long)earliest - (long)now);
437 ASSERT(time_after(earliest, now));
438 rxrpc_set_service_reap_timer(rxnet, earliest);
439 }
440
441 while (!list_empty(&graveyard)) {
442 conn = list_entry(graveyard.next, struct rxrpc_connection,
443 link);
444 list_del_init(&conn->link);
445
446 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
447 rxrpc_kill_connection(conn);
448 }
449
450 _leave("");
451 }
452
453 /*
454 * preemptively destroy all the service connection records rather than
455 * waiting for them to time out
456 */
rxrpc_destroy_all_connections(struct rxrpc_net * rxnet)457 void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
458 {
459 struct rxrpc_connection *conn, *_p;
460 bool leak = false;
461
462 _enter("");
463
464 atomic_dec(&rxnet->nr_conns);
465 rxrpc_destroy_all_client_connections(rxnet);
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, atomic_read(&conn->usage));
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 }
488