1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Shared Memory Communications over RDMA (SMC-R) and RoCE
4  *
5  *  Socket Closing - normal and abnormal
6  *
7  *  Copyright IBM Corp. 2016
8  *
9  *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
10  */
11 
12 #include <linux/workqueue.h>
13 #include <linux/sched/signal.h>
14 
15 #include <net/sock.h>
16 
17 #include "smc.h"
18 #include "smc_tx.h"
19 #include "smc_cdc.h"
20 #include "smc_close.h"
21 
22 #define SMC_CLOSE_WAIT_LISTEN_CLCSOCK_TIME	(5 * HZ)
23 
24 /* release the clcsock that is assigned to the smc_sock */
smc_clcsock_release(struct smc_sock * smc)25 void smc_clcsock_release(struct smc_sock *smc)
26 {
27 	struct socket *tcp;
28 
29 	if (smc->listen_smc && current_work() != &smc->smc_listen_work)
30 		cancel_work_sync(&smc->smc_listen_work);
31 	mutex_lock(&smc->clcsock_release_lock);
32 	if (smc->clcsock) {
33 		tcp = smc->clcsock;
34 		smc->clcsock = NULL;
35 		sock_release(tcp);
36 	}
37 	mutex_unlock(&smc->clcsock_release_lock);
38 }
39 
smc_close_cleanup_listen(struct sock * parent)40 static void smc_close_cleanup_listen(struct sock *parent)
41 {
42 	struct sock *sk;
43 
44 	/* Close non-accepted connections */
45 	while ((sk = smc_accept_dequeue(parent, NULL)))
46 		smc_close_non_accepted(sk);
47 }
48 
49 /* wait for sndbuf data being transmitted */
smc_close_stream_wait(struct smc_sock * smc,long timeout)50 static void smc_close_stream_wait(struct smc_sock *smc, long timeout)
51 {
52 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
53 	struct sock *sk = &smc->sk;
54 
55 	if (!timeout)
56 		return;
57 
58 	if (!smc_tx_prepared_sends(&smc->conn))
59 		return;
60 
61 	smc->wait_close_tx_prepared = 1;
62 	add_wait_queue(sk_sleep(sk), &wait);
63 	while (!signal_pending(current) && timeout) {
64 		int rc;
65 
66 		rc = sk_wait_event(sk, &timeout,
67 				   !smc_tx_prepared_sends(&smc->conn) ||
68 				   (sk->sk_err == ECONNABORTED) ||
69 				   (sk->sk_err == ECONNRESET),
70 				   &wait);
71 		if (rc)
72 			break;
73 	}
74 	remove_wait_queue(sk_sleep(sk), &wait);
75 	smc->wait_close_tx_prepared = 0;
76 }
77 
smc_close_wake_tx_prepared(struct smc_sock * smc)78 void smc_close_wake_tx_prepared(struct smc_sock *smc)
79 {
80 	if (smc->wait_close_tx_prepared)
81 		/* wake up socket closing */
82 		smc->sk.sk_state_change(&smc->sk);
83 }
84 
smc_close_wr(struct smc_connection * conn)85 static int smc_close_wr(struct smc_connection *conn)
86 {
87 	conn->local_tx_ctrl.conn_state_flags.peer_done_writing = 1;
88 
89 	return smc_cdc_get_slot_and_msg_send(conn);
90 }
91 
smc_close_final(struct smc_connection * conn)92 static int smc_close_final(struct smc_connection *conn)
93 {
94 	if (atomic_read(&conn->bytes_to_rcv))
95 		conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
96 	else
97 		conn->local_tx_ctrl.conn_state_flags.peer_conn_closed = 1;
98 
99 	return smc_cdc_get_slot_and_msg_send(conn);
100 }
101 
smc_close_abort(struct smc_connection * conn)102 static int smc_close_abort(struct smc_connection *conn)
103 {
104 	conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
105 
106 	return smc_cdc_get_slot_and_msg_send(conn);
107 }
108 
109 /* terminate smc socket abnormally - active abort
110  * link group is terminated, i.e. RDMA communication no longer possible
111  */
smc_close_active_abort(struct smc_sock * smc)112 static void smc_close_active_abort(struct smc_sock *smc)
113 {
114 	struct sock *sk = &smc->sk;
115 
116 	struct smc_cdc_conn_state_flags *txflags =
117 		&smc->conn.local_tx_ctrl.conn_state_flags;
118 
119 	if (sk->sk_state != SMC_INIT && smc->clcsock && smc->clcsock->sk) {
120 		sk->sk_err = ECONNABORTED;
121 		if (smc->clcsock && smc->clcsock->sk) {
122 			smc->clcsock->sk->sk_err = ECONNABORTED;
123 			smc->clcsock->sk->sk_state_change(smc->clcsock->sk);
124 		}
125 	}
126 	switch (sk->sk_state) {
127 	case SMC_ACTIVE:
128 		sk->sk_state = SMC_PEERABORTWAIT;
129 		release_sock(sk);
130 		cancel_delayed_work_sync(&smc->conn.tx_work);
131 		lock_sock(sk);
132 		sock_put(sk); /* passive closing */
133 		break;
134 	case SMC_APPCLOSEWAIT1:
135 	case SMC_APPCLOSEWAIT2:
136 		if (!smc_cdc_rxed_any_close(&smc->conn))
137 			sk->sk_state = SMC_PEERABORTWAIT;
138 		else
139 			sk->sk_state = SMC_CLOSED;
140 		release_sock(sk);
141 		cancel_delayed_work_sync(&smc->conn.tx_work);
142 		lock_sock(sk);
143 		break;
144 	case SMC_PEERCLOSEWAIT1:
145 	case SMC_PEERCLOSEWAIT2:
146 		if (!txflags->peer_conn_closed) {
147 			/* just SHUTDOWN_SEND done */
148 			sk->sk_state = SMC_PEERABORTWAIT;
149 		} else {
150 			sk->sk_state = SMC_CLOSED;
151 		}
152 		sock_put(sk); /* passive closing */
153 		break;
154 	case SMC_PROCESSABORT:
155 	case SMC_APPFINCLOSEWAIT:
156 		sk->sk_state = SMC_CLOSED;
157 		break;
158 	case SMC_PEERFINCLOSEWAIT:
159 		sock_put(sk); /* passive closing */
160 		break;
161 	case SMC_INIT:
162 	case SMC_PEERABORTWAIT:
163 	case SMC_CLOSED:
164 		break;
165 	}
166 
167 	sock_set_flag(sk, SOCK_DEAD);
168 	sk->sk_state_change(sk);
169 }
170 
smc_close_sent_any_close(struct smc_connection * conn)171 static inline bool smc_close_sent_any_close(struct smc_connection *conn)
172 {
173 	return conn->local_tx_ctrl.conn_state_flags.peer_conn_abort ||
174 	       conn->local_tx_ctrl.conn_state_flags.peer_conn_closed;
175 }
176 
smc_close_active(struct smc_sock * smc)177 int smc_close_active(struct smc_sock *smc)
178 {
179 	struct smc_cdc_conn_state_flags *txflags =
180 		&smc->conn.local_tx_ctrl.conn_state_flags;
181 	struct smc_connection *conn = &smc->conn;
182 	struct sock *sk = &smc->sk;
183 	int old_state;
184 	long timeout;
185 	int rc = 0;
186 
187 	timeout = current->flags & PF_EXITING ?
188 		  0 : sock_flag(sk, SOCK_LINGER) ?
189 		      sk->sk_lingertime : SMC_MAX_STREAM_WAIT_TIMEOUT;
190 
191 	old_state = sk->sk_state;
192 again:
193 	switch (sk->sk_state) {
194 	case SMC_INIT:
195 		sk->sk_state = SMC_CLOSED;
196 		break;
197 	case SMC_LISTEN:
198 		sk->sk_state = SMC_CLOSED;
199 		sk->sk_state_change(sk); /* wake up accept */
200 		if (smc->clcsock && smc->clcsock->sk) {
201 			rc = kernel_sock_shutdown(smc->clcsock, SHUT_RDWR);
202 			/* wake up kernel_accept of smc_tcp_listen_worker */
203 			smc->clcsock->sk->sk_data_ready(smc->clcsock->sk);
204 		}
205 		smc_close_cleanup_listen(sk);
206 		release_sock(sk);
207 		flush_work(&smc->tcp_listen_work);
208 		lock_sock(sk);
209 		break;
210 	case SMC_ACTIVE:
211 		smc_close_stream_wait(smc, timeout);
212 		release_sock(sk);
213 		cancel_delayed_work_sync(&conn->tx_work);
214 		lock_sock(sk);
215 		if (sk->sk_state == SMC_ACTIVE) {
216 			/* send close request */
217 			rc = smc_close_final(conn);
218 			if (rc)
219 				break;
220 			sk->sk_state = SMC_PEERCLOSEWAIT1;
221 		} else {
222 			/* peer event has changed the state */
223 			goto again;
224 		}
225 		break;
226 	case SMC_APPFINCLOSEWAIT:
227 		/* socket already shutdown wr or both (active close) */
228 		if (txflags->peer_done_writing &&
229 		    !smc_close_sent_any_close(conn)) {
230 			/* just shutdown wr done, send close request */
231 			rc = smc_close_final(conn);
232 			if (rc)
233 				break;
234 		}
235 		sk->sk_state = SMC_CLOSED;
236 		break;
237 	case SMC_APPCLOSEWAIT1:
238 	case SMC_APPCLOSEWAIT2:
239 		if (!smc_cdc_rxed_any_close(conn))
240 			smc_close_stream_wait(smc, timeout);
241 		release_sock(sk);
242 		cancel_delayed_work_sync(&conn->tx_work);
243 		lock_sock(sk);
244 		if (sk->sk_state != SMC_APPCLOSEWAIT1 &&
245 		    sk->sk_state != SMC_APPCLOSEWAIT2)
246 			goto again;
247 		/* confirm close from peer */
248 		rc = smc_close_final(conn);
249 		if (rc)
250 			break;
251 		if (smc_cdc_rxed_any_close(conn)) {
252 			/* peer has closed the socket already */
253 			sk->sk_state = SMC_CLOSED;
254 			sock_put(sk); /* postponed passive closing */
255 		} else {
256 			/* peer has just issued a shutdown write */
257 			sk->sk_state = SMC_PEERFINCLOSEWAIT;
258 		}
259 		break;
260 	case SMC_PEERCLOSEWAIT1:
261 	case SMC_PEERCLOSEWAIT2:
262 		if (txflags->peer_done_writing &&
263 		    !smc_close_sent_any_close(conn)) {
264 			/* just shutdown wr done, send close request */
265 			rc = smc_close_final(conn);
266 			if (rc)
267 				break;
268 		}
269 		/* peer sending PeerConnectionClosed will cause transition */
270 		break;
271 	case SMC_PEERFINCLOSEWAIT:
272 		/* peer sending PeerConnectionClosed will cause transition */
273 		break;
274 	case SMC_PROCESSABORT:
275 		smc_close_abort(conn);
276 		sk->sk_state = SMC_CLOSED;
277 		break;
278 	case SMC_PEERABORTWAIT:
279 	case SMC_CLOSED:
280 		/* nothing to do, add tracing in future patch */
281 		break;
282 	}
283 
284 	if (old_state != sk->sk_state)
285 		sk->sk_state_change(sk);
286 	return rc;
287 }
288 
smc_close_passive_abort_received(struct smc_sock * smc)289 static void smc_close_passive_abort_received(struct smc_sock *smc)
290 {
291 	struct smc_cdc_conn_state_flags *txflags =
292 		&smc->conn.local_tx_ctrl.conn_state_flags;
293 	struct sock *sk = &smc->sk;
294 
295 	switch (sk->sk_state) {
296 	case SMC_INIT:
297 	case SMC_ACTIVE:
298 	case SMC_APPCLOSEWAIT1:
299 		sk->sk_state = SMC_PROCESSABORT;
300 		sock_put(sk); /* passive closing */
301 		break;
302 	case SMC_APPFINCLOSEWAIT:
303 		sk->sk_state = SMC_PROCESSABORT;
304 		break;
305 	case SMC_PEERCLOSEWAIT1:
306 	case SMC_PEERCLOSEWAIT2:
307 		if (txflags->peer_done_writing &&
308 		    !smc_close_sent_any_close(&smc->conn))
309 			/* just shutdown, but not yet closed locally */
310 			sk->sk_state = SMC_PROCESSABORT;
311 		else
312 			sk->sk_state = SMC_CLOSED;
313 		sock_put(sk); /* passive closing */
314 		break;
315 	case SMC_APPCLOSEWAIT2:
316 	case SMC_PEERFINCLOSEWAIT:
317 		sk->sk_state = SMC_CLOSED;
318 		sock_put(sk); /* passive closing */
319 		break;
320 	case SMC_PEERABORTWAIT:
321 		sk->sk_state = SMC_CLOSED;
322 		break;
323 	case SMC_PROCESSABORT:
324 	/* nothing to do, add tracing in future patch */
325 		break;
326 	}
327 }
328 
329 /* Either some kind of closing has been received: peer_conn_closed,
330  * peer_conn_abort, or peer_done_writing
331  * or the link group of the connection terminates abnormally.
332  */
smc_close_passive_work(struct work_struct * work)333 static void smc_close_passive_work(struct work_struct *work)
334 {
335 	struct smc_connection *conn = container_of(work,
336 						   struct smc_connection,
337 						   close_work);
338 	struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
339 	struct smc_cdc_conn_state_flags *rxflags;
340 	bool release_clcsock = false;
341 	struct sock *sk = &smc->sk;
342 	int old_state;
343 
344 	lock_sock(sk);
345 	old_state = sk->sk_state;
346 
347 	if (!conn->alert_token_local) {
348 		/* abnormal termination */
349 		smc_close_active_abort(smc);
350 		goto wakeup;
351 	}
352 
353 	rxflags = &conn->local_rx_ctrl.conn_state_flags;
354 	if (rxflags->peer_conn_abort) {
355 		/* peer has not received all data */
356 		smc_close_passive_abort_received(smc);
357 		release_sock(&smc->sk);
358 		cancel_delayed_work_sync(&conn->tx_work);
359 		lock_sock(&smc->sk);
360 		goto wakeup;
361 	}
362 
363 	switch (sk->sk_state) {
364 	case SMC_INIT:
365 		sk->sk_state = SMC_APPCLOSEWAIT1;
366 		break;
367 	case SMC_ACTIVE:
368 		sk->sk_state = SMC_APPCLOSEWAIT1;
369 		/* postpone sock_put() for passive closing to cover
370 		 * received SEND_SHUTDOWN as well
371 		 */
372 		break;
373 	case SMC_PEERCLOSEWAIT1:
374 		if (rxflags->peer_done_writing)
375 			sk->sk_state = SMC_PEERCLOSEWAIT2;
376 		/* fall through */
377 		/* to check for closing */
378 	case SMC_PEERCLOSEWAIT2:
379 		if (!smc_cdc_rxed_any_close(conn))
380 			break;
381 		if (sock_flag(sk, SOCK_DEAD) &&
382 		    smc_close_sent_any_close(conn)) {
383 			/* smc_release has already been called locally */
384 			sk->sk_state = SMC_CLOSED;
385 		} else {
386 			/* just shutdown, but not yet closed locally */
387 			sk->sk_state = SMC_APPFINCLOSEWAIT;
388 		}
389 		sock_put(sk); /* passive closing */
390 		break;
391 	case SMC_PEERFINCLOSEWAIT:
392 		if (smc_cdc_rxed_any_close(conn)) {
393 			sk->sk_state = SMC_CLOSED;
394 			sock_put(sk); /* passive closing */
395 		}
396 		break;
397 	case SMC_APPCLOSEWAIT1:
398 	case SMC_APPCLOSEWAIT2:
399 		/* postpone sock_put() for passive closing to cover
400 		 * received SEND_SHUTDOWN as well
401 		 */
402 		break;
403 	case SMC_APPFINCLOSEWAIT:
404 	case SMC_PEERABORTWAIT:
405 	case SMC_PROCESSABORT:
406 	case SMC_CLOSED:
407 		/* nothing to do, add tracing in future patch */
408 		break;
409 	}
410 
411 wakeup:
412 	sk->sk_data_ready(sk); /* wakeup blocked rcvbuf consumers */
413 	sk->sk_write_space(sk); /* wakeup blocked sndbuf producers */
414 
415 	if (old_state != sk->sk_state) {
416 		sk->sk_state_change(sk);
417 		if ((sk->sk_state == SMC_CLOSED) &&
418 		    (sock_flag(sk, SOCK_DEAD) || !sk->sk_socket)) {
419 			smc_conn_free(conn);
420 			if (smc->clcsock)
421 				release_clcsock = true;
422 		}
423 	}
424 	release_sock(sk);
425 	if (release_clcsock)
426 		smc_clcsock_release(smc);
427 	sock_put(sk); /* sock_hold done by schedulers of close_work */
428 }
429 
smc_close_shutdown_write(struct smc_sock * smc)430 int smc_close_shutdown_write(struct smc_sock *smc)
431 {
432 	struct smc_connection *conn = &smc->conn;
433 	struct sock *sk = &smc->sk;
434 	int old_state;
435 	long timeout;
436 	int rc = 0;
437 
438 	timeout = current->flags & PF_EXITING ?
439 		  0 : sock_flag(sk, SOCK_LINGER) ?
440 		      sk->sk_lingertime : SMC_MAX_STREAM_WAIT_TIMEOUT;
441 
442 	old_state = sk->sk_state;
443 again:
444 	switch (sk->sk_state) {
445 	case SMC_ACTIVE:
446 		smc_close_stream_wait(smc, timeout);
447 		release_sock(sk);
448 		cancel_delayed_work_sync(&conn->tx_work);
449 		lock_sock(sk);
450 		if (sk->sk_state != SMC_ACTIVE)
451 			goto again;
452 		/* send close wr request */
453 		rc = smc_close_wr(conn);
454 		if (rc)
455 			break;
456 		sk->sk_state = SMC_PEERCLOSEWAIT1;
457 		break;
458 	case SMC_APPCLOSEWAIT1:
459 		/* passive close */
460 		if (!smc_cdc_rxed_any_close(conn))
461 			smc_close_stream_wait(smc, timeout);
462 		release_sock(sk);
463 		cancel_delayed_work_sync(&conn->tx_work);
464 		lock_sock(sk);
465 		if (sk->sk_state != SMC_APPCLOSEWAIT1)
466 			goto again;
467 		/* confirm close from peer */
468 		rc = smc_close_wr(conn);
469 		if (rc)
470 			break;
471 		sk->sk_state = SMC_APPCLOSEWAIT2;
472 		break;
473 	case SMC_APPCLOSEWAIT2:
474 	case SMC_PEERFINCLOSEWAIT:
475 	case SMC_PEERCLOSEWAIT1:
476 	case SMC_PEERCLOSEWAIT2:
477 	case SMC_APPFINCLOSEWAIT:
478 	case SMC_PROCESSABORT:
479 	case SMC_PEERABORTWAIT:
480 		/* nothing to do, add tracing in future patch */
481 		break;
482 	}
483 
484 	if (old_state != sk->sk_state)
485 		sk->sk_state_change(sk);
486 	return rc;
487 }
488 
489 /* Initialize close properties on connection establishment. */
smc_close_init(struct smc_sock * smc)490 void smc_close_init(struct smc_sock *smc)
491 {
492 	INIT_WORK(&smc->conn.close_work, smc_close_passive_work);
493 }
494