xref: /openbmc/linux/net/rds/connection.c (revision fd589a8f)
1 /*
2  * Copyright (c) 2006 Oracle.  All rights reserved.
3  *
4  * This software is available to you under a choice of one of two
5  * licenses.  You may choose to be licensed under the terms of the GNU
6  * General Public License (GPL) Version 2, available from the file
7  * COPYING in the main directory of this source tree, or the
8  * OpenIB.org BSD license below:
9  *
10  *     Redistribution and use in source and binary forms, with or
11  *     without modification, are permitted provided that the following
12  *     conditions are met:
13  *
14  *      - Redistributions of source code must retain the above
15  *        copyright notice, this list of conditions and the following
16  *        disclaimer.
17  *
18  *      - Redistributions in binary form must reproduce the above
19  *        copyright notice, this list of conditions and the following
20  *        disclaimer in the documentation and/or other materials
21  *        provided with the distribution.
22  *
23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30  * SOFTWARE.
31  *
32  */
33 #include <linux/kernel.h>
34 #include <linux/list.h>
35 #include <net/inet_hashtables.h>
36 
37 #include "rds.h"
38 #include "loop.h"
39 #include "rdma.h"
40 
41 #define RDS_CONNECTION_HASH_BITS 12
42 #define RDS_CONNECTION_HASH_ENTRIES (1 << RDS_CONNECTION_HASH_BITS)
43 #define RDS_CONNECTION_HASH_MASK (RDS_CONNECTION_HASH_ENTRIES - 1)
44 
45 /* converting this to RCU is a chore for another day.. */
46 static DEFINE_SPINLOCK(rds_conn_lock);
47 static unsigned long rds_conn_count;
48 static struct hlist_head rds_conn_hash[RDS_CONNECTION_HASH_ENTRIES];
49 static struct kmem_cache *rds_conn_slab;
50 
51 static struct hlist_head *rds_conn_bucket(__be32 laddr, __be32 faddr)
52 {
53 	/* Pass NULL, don't need struct net for hash */
54 	unsigned long hash = inet_ehashfn(NULL,
55 					  be32_to_cpu(laddr), 0,
56 					  be32_to_cpu(faddr), 0);
57 	return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
58 }
59 
60 #define rds_conn_info_set(var, test, suffix) do {		\
61 	if (test)						\
62 		var |= RDS_INFO_CONNECTION_FLAG_##suffix;	\
63 } while (0)
64 
65 static inline int rds_conn_is_sending(struct rds_connection *conn)
66 {
67 	int ret = 0;
68 
69 	if (!mutex_trylock(&conn->c_send_lock))
70 		ret = 1;
71 	else
72 		mutex_unlock(&conn->c_send_lock);
73 
74 	return ret;
75 }
76 
77 static struct rds_connection *rds_conn_lookup(struct hlist_head *head,
78 					      __be32 laddr, __be32 faddr,
79 					      struct rds_transport *trans)
80 {
81 	struct rds_connection *conn, *ret = NULL;
82 	struct hlist_node *pos;
83 
84 	hlist_for_each_entry(conn, pos, head, c_hash_node) {
85 		if (conn->c_faddr == faddr && conn->c_laddr == laddr &&
86 				conn->c_trans == trans) {
87 			ret = conn;
88 			break;
89 		}
90 	}
91 	rdsdebug("returning conn %p for %pI4 -> %pI4\n", ret,
92 		 &laddr, &faddr);
93 	return ret;
94 }
95 
96 /*
97  * This is called by transports as they're bringing down a connection.
98  * It clears partial message state so that the transport can start sending
99  * and receiving over this connection again in the future.  It is up to
100  * the transport to have serialized this call with its send and recv.
101  */
102 void rds_conn_reset(struct rds_connection *conn)
103 {
104 	rdsdebug("connection %pI4 to %pI4 reset\n",
105 	  &conn->c_laddr, &conn->c_faddr);
106 
107 	rds_stats_inc(s_conn_reset);
108 	rds_send_reset(conn);
109 	conn->c_flags = 0;
110 
111 	/* Do not clear next_rx_seq here, else we cannot distinguish
112 	 * retransmitted packets from new packets, and will hand all
113 	 * of them to the application. That is not consistent with the
114 	 * reliability guarantees of RDS. */
115 }
116 
117 /*
118  * There is only every one 'conn' for a given pair of addresses in the
119  * system at a time.  They contain messages to be retransmitted and so
120  * span the lifetime of the actual underlying transport connections.
121  *
122  * For now they are not garbage collected once they're created.  They
123  * are torn down as the module is removed, if ever.
124  */
125 static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
126 				       struct rds_transport *trans, gfp_t gfp,
127 				       int is_outgoing)
128 {
129 	struct rds_connection *conn, *parent = NULL;
130 	struct hlist_head *head = rds_conn_bucket(laddr, faddr);
131 	unsigned long flags;
132 	int ret;
133 
134 	spin_lock_irqsave(&rds_conn_lock, flags);
135 	conn = rds_conn_lookup(head, laddr, faddr, trans);
136 	if (conn
137 	 && conn->c_loopback
138 	 && conn->c_trans != &rds_loop_transport
139 	 && !is_outgoing) {
140 		/* This is a looped back IB connection, and we're
141 		 * called by the code handling the incoming connect.
142 		 * We need a second connection object into which we
143 		 * can stick the other QP. */
144 		parent = conn;
145 		conn = parent->c_passive;
146 	}
147 	spin_unlock_irqrestore(&rds_conn_lock, flags);
148 	if (conn)
149 		goto out;
150 
151 	conn = kmem_cache_zalloc(rds_conn_slab, gfp);
152 	if (conn == NULL) {
153 		conn = ERR_PTR(-ENOMEM);
154 		goto out;
155 	}
156 
157 	INIT_HLIST_NODE(&conn->c_hash_node);
158 	conn->c_laddr = laddr;
159 	conn->c_faddr = faddr;
160 	spin_lock_init(&conn->c_lock);
161 	conn->c_next_tx_seq = 1;
162 
163 	mutex_init(&conn->c_send_lock);
164 	INIT_LIST_HEAD(&conn->c_send_queue);
165 	INIT_LIST_HEAD(&conn->c_retrans);
166 
167 	ret = rds_cong_get_maps(conn);
168 	if (ret) {
169 		kmem_cache_free(rds_conn_slab, conn);
170 		conn = ERR_PTR(ret);
171 		goto out;
172 	}
173 
174 	/*
175 	 * This is where a connection becomes loopback.  If *any* RDS sockets
176 	 * can bind to the destination address then we'd rather the messages
177 	 * flow through loopback rather than either transport.
178 	 */
179 	if (rds_trans_get_preferred(faddr)) {
180 		conn->c_loopback = 1;
181 		if (is_outgoing && trans->t_prefer_loopback) {
182 			/* "outgoing" connection - and the transport
183 			 * says it wants the connection handled by the
184 			 * loopback transport. This is what TCP does.
185 			 */
186 			trans = &rds_loop_transport;
187 		}
188 	}
189 
190 	conn->c_trans = trans;
191 
192 	ret = trans->conn_alloc(conn, gfp);
193 	if (ret) {
194 		kmem_cache_free(rds_conn_slab, conn);
195 		conn = ERR_PTR(ret);
196 		goto out;
197 	}
198 
199 	atomic_set(&conn->c_state, RDS_CONN_DOWN);
200 	conn->c_reconnect_jiffies = 0;
201 	INIT_DELAYED_WORK(&conn->c_send_w, rds_send_worker);
202 	INIT_DELAYED_WORK(&conn->c_recv_w, rds_recv_worker);
203 	INIT_DELAYED_WORK(&conn->c_conn_w, rds_connect_worker);
204 	INIT_WORK(&conn->c_down_w, rds_shutdown_worker);
205 	mutex_init(&conn->c_cm_lock);
206 	conn->c_flags = 0;
207 
208 	rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
209 	  conn, &laddr, &faddr,
210 	  trans->t_name ? trans->t_name : "[unknown]",
211 	  is_outgoing ? "(outgoing)" : "");
212 
213 	/*
214 	 * Since we ran without holding the conn lock, someone could
215 	 * have created the same conn (either normal or passive) in the
216 	 * interim. We check while holding the lock. If we won, we complete
217 	 * init and return our conn. If we lost, we rollback and return the
218 	 * other one.
219 	 */
220 	spin_lock_irqsave(&rds_conn_lock, flags);
221 	if (parent) {
222 		/* Creating passive conn */
223 		if (parent->c_passive) {
224 			trans->conn_free(conn->c_transport_data);
225 			kmem_cache_free(rds_conn_slab, conn);
226 			conn = parent->c_passive;
227 		} else {
228 			parent->c_passive = conn;
229 			rds_cong_add_conn(conn);
230 			rds_conn_count++;
231 		}
232 	} else {
233 		/* Creating normal conn */
234 		struct rds_connection *found;
235 
236 		found = rds_conn_lookup(head, laddr, faddr, trans);
237 		if (found) {
238 			trans->conn_free(conn->c_transport_data);
239 			kmem_cache_free(rds_conn_slab, conn);
240 			conn = found;
241 		} else {
242 			hlist_add_head(&conn->c_hash_node, head);
243 			rds_cong_add_conn(conn);
244 			rds_conn_count++;
245 		}
246 	}
247 	spin_unlock_irqrestore(&rds_conn_lock, flags);
248 
249 out:
250 	return conn;
251 }
252 
253 struct rds_connection *rds_conn_create(__be32 laddr, __be32 faddr,
254 				       struct rds_transport *trans, gfp_t gfp)
255 {
256 	return __rds_conn_create(laddr, faddr, trans, gfp, 0);
257 }
258 EXPORT_SYMBOL_GPL(rds_conn_create);
259 
260 struct rds_connection *rds_conn_create_outgoing(__be32 laddr, __be32 faddr,
261 				       struct rds_transport *trans, gfp_t gfp)
262 {
263 	return __rds_conn_create(laddr, faddr, trans, gfp, 1);
264 }
265 EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
266 
267 void rds_conn_destroy(struct rds_connection *conn)
268 {
269 	struct rds_message *rm, *rtmp;
270 
271 	rdsdebug("freeing conn %p for %pI4 -> "
272 		 "%pI4\n", conn, &conn->c_laddr,
273 		 &conn->c_faddr);
274 
275 	hlist_del_init(&conn->c_hash_node);
276 
277 	/* wait for the rds thread to shut it down */
278 	atomic_set(&conn->c_state, RDS_CONN_ERROR);
279 	cancel_delayed_work(&conn->c_conn_w);
280 	queue_work(rds_wq, &conn->c_down_w);
281 	flush_workqueue(rds_wq);
282 
283 	/* tear down queued messages */
284 	list_for_each_entry_safe(rm, rtmp,
285 				 &conn->c_send_queue,
286 				 m_conn_item) {
287 		list_del_init(&rm->m_conn_item);
288 		BUG_ON(!list_empty(&rm->m_sock_item));
289 		rds_message_put(rm);
290 	}
291 	if (conn->c_xmit_rm)
292 		rds_message_put(conn->c_xmit_rm);
293 
294 	conn->c_trans->conn_free(conn->c_transport_data);
295 
296 	/*
297 	 * The congestion maps aren't freed up here.  They're
298 	 * freed by rds_cong_exit() after all the connections
299 	 * have been freed.
300 	 */
301 	rds_cong_remove_conn(conn);
302 
303 	BUG_ON(!list_empty(&conn->c_retrans));
304 	kmem_cache_free(rds_conn_slab, conn);
305 
306 	rds_conn_count--;
307 }
308 EXPORT_SYMBOL_GPL(rds_conn_destroy);
309 
310 static void rds_conn_message_info(struct socket *sock, unsigned int len,
311 				  struct rds_info_iterator *iter,
312 				  struct rds_info_lengths *lens,
313 				  int want_send)
314 {
315 	struct hlist_head *head;
316 	struct hlist_node *pos;
317 	struct list_head *list;
318 	struct rds_connection *conn;
319 	struct rds_message *rm;
320 	unsigned long flags;
321 	unsigned int total = 0;
322 	size_t i;
323 
324 	len /= sizeof(struct rds_info_message);
325 
326 	spin_lock_irqsave(&rds_conn_lock, flags);
327 
328 	for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
329 	     i++, head++) {
330 		hlist_for_each_entry(conn, pos, head, c_hash_node) {
331 			if (want_send)
332 				list = &conn->c_send_queue;
333 			else
334 				list = &conn->c_retrans;
335 
336 			spin_lock(&conn->c_lock);
337 
338 			/* XXX too lazy to maintain counts.. */
339 			list_for_each_entry(rm, list, m_conn_item) {
340 				total++;
341 				if (total <= len)
342 					rds_inc_info_copy(&rm->m_inc, iter,
343 							  conn->c_laddr,
344 							  conn->c_faddr, 0);
345 			}
346 
347 			spin_unlock(&conn->c_lock);
348 		}
349 	}
350 
351 	spin_unlock_irqrestore(&rds_conn_lock, flags);
352 
353 	lens->nr = total;
354 	lens->each = sizeof(struct rds_info_message);
355 }
356 
357 static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
358 				       struct rds_info_iterator *iter,
359 				       struct rds_info_lengths *lens)
360 {
361 	rds_conn_message_info(sock, len, iter, lens, 1);
362 }
363 
364 static void rds_conn_message_info_retrans(struct socket *sock,
365 					  unsigned int len,
366 					  struct rds_info_iterator *iter,
367 					  struct rds_info_lengths *lens)
368 {
369 	rds_conn_message_info(sock, len, iter, lens, 0);
370 }
371 
372 void rds_for_each_conn_info(struct socket *sock, unsigned int len,
373 			  struct rds_info_iterator *iter,
374 			  struct rds_info_lengths *lens,
375 			  int (*visitor)(struct rds_connection *, void *),
376 			  size_t item_len)
377 {
378 	uint64_t buffer[(item_len + 7) / 8];
379 	struct hlist_head *head;
380 	struct hlist_node *pos;
381 	struct hlist_node *tmp;
382 	struct rds_connection *conn;
383 	unsigned long flags;
384 	size_t i;
385 
386 	spin_lock_irqsave(&rds_conn_lock, flags);
387 
388 	lens->nr = 0;
389 	lens->each = item_len;
390 
391 	for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
392 	     i++, head++) {
393 		hlist_for_each_entry_safe(conn, pos, tmp, head, c_hash_node) {
394 
395 			/* XXX no c_lock usage.. */
396 			if (!visitor(conn, buffer))
397 				continue;
398 
399 			/* We copy as much as we can fit in the buffer,
400 			 * but we count all items so that the caller
401 			 * can resize the buffer. */
402 			if (len >= item_len) {
403 				rds_info_copy(iter, buffer, item_len);
404 				len -= item_len;
405 			}
406 			lens->nr++;
407 		}
408 	}
409 
410 	spin_unlock_irqrestore(&rds_conn_lock, flags);
411 }
412 EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
413 
414 static int rds_conn_info_visitor(struct rds_connection *conn,
415 				  void *buffer)
416 {
417 	struct rds_info_connection *cinfo = buffer;
418 
419 	cinfo->next_tx_seq = conn->c_next_tx_seq;
420 	cinfo->next_rx_seq = conn->c_next_rx_seq;
421 	cinfo->laddr = conn->c_laddr;
422 	cinfo->faddr = conn->c_faddr;
423 	strncpy(cinfo->transport, conn->c_trans->t_name,
424 		sizeof(cinfo->transport));
425 	cinfo->flags = 0;
426 
427 	rds_conn_info_set(cinfo->flags,
428 			  rds_conn_is_sending(conn), SENDING);
429 	/* XXX Future: return the state rather than these funky bits */
430 	rds_conn_info_set(cinfo->flags,
431 			  atomic_read(&conn->c_state) == RDS_CONN_CONNECTING,
432 			  CONNECTING);
433 	rds_conn_info_set(cinfo->flags,
434 			  atomic_read(&conn->c_state) == RDS_CONN_UP,
435 			  CONNECTED);
436 	return 1;
437 }
438 
439 static void rds_conn_info(struct socket *sock, unsigned int len,
440 			  struct rds_info_iterator *iter,
441 			  struct rds_info_lengths *lens)
442 {
443 	rds_for_each_conn_info(sock, len, iter, lens,
444 				rds_conn_info_visitor,
445 				sizeof(struct rds_info_connection));
446 }
447 
448 int __init rds_conn_init(void)
449 {
450 	rds_conn_slab = kmem_cache_create("rds_connection",
451 					  sizeof(struct rds_connection),
452 					  0, 0, NULL);
453 	if (rds_conn_slab == NULL)
454 		return -ENOMEM;
455 
456 	rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
457 	rds_info_register_func(RDS_INFO_SEND_MESSAGES,
458 			       rds_conn_message_info_send);
459 	rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
460 			       rds_conn_message_info_retrans);
461 
462 	return 0;
463 }
464 
465 void rds_conn_exit(void)
466 {
467 	rds_loop_exit();
468 
469 	WARN_ON(!hlist_empty(rds_conn_hash));
470 
471 	kmem_cache_destroy(rds_conn_slab);
472 
473 	rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
474 	rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
475 				 rds_conn_message_info_send);
476 	rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
477 				 rds_conn_message_info_retrans);
478 }
479 
480 /*
481  * Force a disconnect
482  */
483 void rds_conn_drop(struct rds_connection *conn)
484 {
485 	atomic_set(&conn->c_state, RDS_CONN_ERROR);
486 	queue_work(rds_wq, &conn->c_down_w);
487 }
488 EXPORT_SYMBOL_GPL(rds_conn_drop);
489 
490 /*
491  * An error occurred on the connection
492  */
493 void
494 __rds_conn_error(struct rds_connection *conn, const char *fmt, ...)
495 {
496 	va_list ap;
497 
498 	va_start(ap, fmt);
499 	vprintk(fmt, ap);
500 	va_end(ap);
501 
502 	rds_conn_drop(conn);
503 }
504