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1/* RxRPC virtual connection handler, common bits.
2 *
3 * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/module.h>
15#include <linux/slab.h>
16#include <linux/net.h>
17#include <linux/skbuff.h>
18#include "ar-internal.h"
19
20/*
21 * Time till a connection expires after last use (in seconds).
22 */
23unsigned int __read_mostly rxrpc_connection_expiry = 10 * 60;
24unsigned int __read_mostly rxrpc_closed_conn_expiry = 10;
25
26static void rxrpc_destroy_connection(struct rcu_head *);
27
28static void rxrpc_connection_timer(struct timer_list *timer)
29{
30 struct rxrpc_connection *conn =
31 container_of(timer, struct rxrpc_connection, timer);
32
33 rxrpc_queue_conn(conn);
34}
35
36/*
37 * allocate a new connection
38 */
39struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
40{
41 struct rxrpc_connection *conn;
42
43 _enter("");
44
45 conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
46 if (conn) {
47 INIT_LIST_HEAD(&conn->cache_link);
48 spin_lock_init(&conn->channel_lock);
49 INIT_LIST_HEAD(&conn->waiting_calls);
50 timer_setup(&conn->timer, &rxrpc_connection_timer, 0);
51 INIT_WORK(&conn->processor, &rxrpc_process_connection);
52 INIT_LIST_HEAD(&conn->proc_link);
53 INIT_LIST_HEAD(&conn->link);
54 skb_queue_head_init(&conn->rx_queue);
55 conn->security = &rxrpc_no_security;
56 spin_lock_init(&conn->state_lock);
57 conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
58 conn->size_align = 4;
59 conn->idle_timestamp = jiffies;
60 }
61
62 _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
63 return conn;
64}
65
66/*
67 * Look up a connection in the cache by protocol parameters.
68 *
69 * If successful, a pointer to the connection is returned, but no ref is taken.
70 * NULL is returned if there is no match.
71 *
72 * The caller must be holding the RCU read lock.
73 */
74struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
75 struct sk_buff *skb)
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(local, &srx, skb) < 0)
86 goto not_found;
87
88 k.epoch = sp->hdr.epoch;
89 k.cid = sp->hdr.cid & RXRPC_CIDMASK;
90
91 /* We may have to handle mixing IPv4 and IPv6 */
92 if (srx.transport.family != local->srx.transport.family) {
93 pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
94 srx.transport.family,
95 local->srx.transport.family);
96 goto not_found;
97 }
98
99 k.epoch = sp->hdr.epoch;
100 k.cid = sp->hdr.cid & RXRPC_CIDMASK;
101
102 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED) {
103 /* We need to look up service connections by the full protocol
104 * parameter set. We look up the peer first as an intermediate
105 * step and then the connection from the peer's tree.
106 */
107 peer = rxrpc_lookup_peer_rcu(local, &srx);
108 if (!peer)
109 goto not_found;
110 conn = rxrpc_find_service_conn_rcu(peer, skb);
111 if (!conn || atomic_read(&conn->usage) == 0)
112 goto not_found;
113 _leave(" = %p", conn);
114 return conn;
115 } else {
116 /* Look up client connections by connection ID alone as their
117 * IDs are unique for this machine.
118 */
119 conn = idr_find(&rxrpc_client_conn_ids,
120 sp->hdr.cid >> RXRPC_CIDSHIFT);
121 if (!conn || atomic_read(&conn->usage) == 0) {
122 _debug("no conn");
123 goto not_found;
124 }
125
126 if (conn->proto.epoch != k.epoch ||
127 conn->params.local != local)
128 goto not_found;
129
130 peer = conn->params.peer;
131 switch (srx.transport.family) {
132 case AF_INET:
133 if (peer->srx.transport.sin.sin_port !=
134 srx.transport.sin.sin_port ||
135 peer->srx.transport.sin.sin_addr.s_addr !=
136 srx.transport.sin.sin_addr.s_addr)
137 goto not_found;
138 break;
139#ifdef CONFIG_AF_RXRPC_IPV6
140 case AF_INET6:
141 if (peer->srx.transport.sin6.sin6_port !=
142 srx.transport.sin6.sin6_port ||
143 memcmp(&peer->srx.transport.sin6.sin6_addr,
144 &srx.transport.sin6.sin6_addr,
145 sizeof(struct in6_addr)) != 0)
146 goto not_found;
147 break;
148#endif
149 default:
150 BUG();
151 }
152
153 _leave(" = %p", conn);
154 return conn;
155 }
156
157not_found:
158 _leave(" = NULL");
159 return NULL;
160}
161
162/*
163 * Disconnect a call and clear any channel it occupies when that call
164 * terminates. The caller must hold the channel_lock and must release the
165 * call's ref on the connection.
166 */
167void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
168 struct rxrpc_call *call)
169{
170 struct rxrpc_channel *chan =
171 &conn->channels[call->cid & RXRPC_CHANNELMASK];
172
173 _enter("%d,%x", conn->debug_id, call->cid);
174
175 if (rcu_access_pointer(chan->call) == call) {
176 /* Save the result of the call so that we can repeat it if necessary
177 * through the channel, whilst disposing of the actual call record.
178 */
179 trace_rxrpc_disconnect_call(call);
180 switch (call->completion) {
181 case RXRPC_CALL_SUCCEEDED:
182 chan->last_seq = call->rx_hard_ack;
183 chan->last_type = RXRPC_PACKET_TYPE_ACK;
184 break;
185 case RXRPC_CALL_LOCALLY_ABORTED:
186 chan->last_abort = call->abort_code;
187 chan->last_type = RXRPC_PACKET_TYPE_ABORT;
188 break;
189 default:
190 chan->last_abort = RX_USER_ABORT;
191 chan->last_type = RXRPC_PACKET_TYPE_ABORT;
192 break;
193 }
194
195 /* Sync with rxrpc_conn_retransmit(). */
196 smp_wmb();
197 chan->last_call = chan->call_id;
198 chan->call_id = chan->call_counter;
199
200 rcu_assign_pointer(chan->call, NULL);
201 }
202
203 _leave("");
204}
205
206/*
207 * Disconnect a call and clear any channel it occupies when that call
208 * terminates.
209 */
210void rxrpc_disconnect_call(struct rxrpc_call *call)
211{
212 struct rxrpc_connection *conn = call->conn;
213
214 call->peer->cong_cwnd = call->cong_cwnd;
215
216 spin_lock_bh(&conn->params.peer->lock);
217 hlist_del_init(&call->error_link);
218 spin_unlock_bh(&conn->params.peer->lock);
219
220 if (rxrpc_is_client_call(call))
221 return rxrpc_disconnect_client_call(call);
222
223 spin_lock(&conn->channel_lock);
224 __rxrpc_disconnect_call(conn, call);
225 spin_unlock(&conn->channel_lock);
226
227 call->conn = NULL;
228 conn->idle_timestamp = jiffies;
229 rxrpc_put_connection(conn);
230}
231
232/*
233 * Kill off a connection.
234 */
235void 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 */
266bool rxrpc_queue_conn(struct rxrpc_connection *conn)
267{
268 const void *here = __builtin_return_address(0);
269 int n = __atomic_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, 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 */
282void 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, rxrpc_conn_seen, n, here);
289 }
290}
291
292/*
293 * Get a ref on a connection.
294 */
295void 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, rxrpc_conn_got, n, here);
301}
302
303/*
304 * Try to get a ref on a connection.
305 */
306struct rxrpc_connection *
307rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
308{
309 const void *here = __builtin_return_address(0);
310
311 if (conn) {
312 int n = __atomic_add_unless(&conn->usage, 1, 0);
313 if (n > 0)
314 trace_rxrpc_conn(conn, 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 */
324static 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 */
334void rxrpc_put_service_conn(struct rxrpc_connection *conn)
335{
336 const void *here = __builtin_return_address(0);
337 int n;
338
339 n = atomic_dec_return(&conn->usage);
340 trace_rxrpc_conn(conn, 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 */
350static 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 */
380void 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) {
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, 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 */
457void 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}