1 /******************************************************************************
2 *******************************************************************************
3 **
4 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
5 **  Copyright (C) 2004-2009 Red Hat, Inc.  All rights reserved.
6 **
7 **  This copyrighted material is made available to anyone wishing to use,
8 **  modify, copy, or redistribute it subject to the terms and conditions
9 **  of the GNU General Public License v.2.
10 **
11 *******************************************************************************
12 ******************************************************************************/
13 
14 /*
15  * lowcomms.c
16  *
17  * This is the "low-level" comms layer.
18  *
19  * It is responsible for sending/receiving messages
20  * from other nodes in the cluster.
21  *
22  * Cluster nodes are referred to by their nodeids. nodeids are
23  * simply 32 bit numbers to the locking module - if they need to
24  * be expanded for the cluster infrastructure then that is its
25  * responsibility. It is this layer's
26  * responsibility to resolve these into IP address or
27  * whatever it needs for inter-node communication.
28  *
29  * The comms level is two kernel threads that deal mainly with
30  * the receiving of messages from other nodes and passing them
31  * up to the mid-level comms layer (which understands the
32  * message format) for execution by the locking core, and
33  * a send thread which does all the setting up of connections
34  * to remote nodes and the sending of data. Threads are not allowed
35  * to send their own data because it may cause them to wait in times
36  * of high load. Also, this way, the sending thread can collect together
37  * messages bound for one node and send them in one block.
38  *
39  * lowcomms will choose to use either TCP or SCTP as its transport layer
40  * depending on the configuration variable 'protocol'. This should be set
41  * to 0 (default) for TCP or 1 for SCTP. It should be configured using a
42  * cluster-wide mechanism as it must be the same on all nodes of the cluster
43  * for the DLM to function.
44  *
45  */
46 
47 #include <asm/ioctls.h>
48 #include <net/sock.h>
49 #include <net/tcp.h>
50 #include <linux/pagemap.h>
51 #include <linux/file.h>
52 #include <linux/mutex.h>
53 #include <linux/sctp.h>
54 #include <linux/slab.h>
55 #include <net/sctp/sctp.h>
56 #include <net/ipv6.h>
57 
58 #include "dlm_internal.h"
59 #include "lowcomms.h"
60 #include "midcomms.h"
61 #include "config.h"
62 
63 #define NEEDED_RMEM (4*1024*1024)
64 #define CONN_HASH_SIZE 32
65 
66 /* Number of messages to send before rescheduling */
67 #define MAX_SEND_MSG_COUNT 25
68 
69 struct cbuf {
70 	unsigned int base;
71 	unsigned int len;
72 	unsigned int mask;
73 };
74 
cbuf_add(struct cbuf * cb,int n)75 static void cbuf_add(struct cbuf *cb, int n)
76 {
77 	cb->len += n;
78 }
79 
cbuf_data(struct cbuf * cb)80 static int cbuf_data(struct cbuf *cb)
81 {
82 	return ((cb->base + cb->len) & cb->mask);
83 }
84 
cbuf_init(struct cbuf * cb,int size)85 static void cbuf_init(struct cbuf *cb, int size)
86 {
87 	cb->base = cb->len = 0;
88 	cb->mask = size-1;
89 }
90 
cbuf_eat(struct cbuf * cb,int n)91 static void cbuf_eat(struct cbuf *cb, int n)
92 {
93 	cb->len  -= n;
94 	cb->base += n;
95 	cb->base &= cb->mask;
96 }
97 
cbuf_empty(struct cbuf * cb)98 static bool cbuf_empty(struct cbuf *cb)
99 {
100 	return cb->len == 0;
101 }
102 
103 struct connection {
104 	struct socket *sock;	/* NULL if not connected */
105 	uint32_t nodeid;	/* So we know who we are in the list */
106 	struct mutex sock_mutex;
107 	unsigned long flags;
108 #define CF_READ_PENDING 1
109 #define CF_WRITE_PENDING 2
110 #define CF_INIT_PENDING 4
111 #define CF_IS_OTHERCON 5
112 #define CF_CLOSE 6
113 #define CF_APP_LIMITED 7
114 #define CF_CLOSING 8
115 	struct list_head writequeue;  /* List of outgoing writequeue_entries */
116 	spinlock_t writequeue_lock;
117 	int (*rx_action) (struct connection *);	/* What to do when active */
118 	void (*connect_action) (struct connection *);	/* What to do to connect */
119 	struct page *rx_page;
120 	struct cbuf cb;
121 	int retries;
122 #define MAX_CONNECT_RETRIES 3
123 	struct hlist_node list;
124 	struct connection *othercon;
125 	struct work_struct rwork; /* Receive workqueue */
126 	struct work_struct swork; /* Send workqueue */
127 };
128 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
129 
130 /* An entry waiting to be sent */
131 struct writequeue_entry {
132 	struct list_head list;
133 	struct page *page;
134 	int offset;
135 	int len;
136 	int end;
137 	int users;
138 	struct connection *con;
139 };
140 
141 struct dlm_node_addr {
142 	struct list_head list;
143 	int nodeid;
144 	int addr_count;
145 	int curr_addr_index;
146 	struct sockaddr_storage *addr[DLM_MAX_ADDR_COUNT];
147 };
148 
149 static struct listen_sock_callbacks {
150 	void (*sk_error_report)(struct sock *);
151 	void (*sk_data_ready)(struct sock *);
152 	void (*sk_state_change)(struct sock *);
153 	void (*sk_write_space)(struct sock *);
154 } listen_sock;
155 
156 static LIST_HEAD(dlm_node_addrs);
157 static DEFINE_SPINLOCK(dlm_node_addrs_spin);
158 
159 static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
160 static int dlm_local_count;
161 static int dlm_allow_conn;
162 
163 /* Work queues */
164 static struct workqueue_struct *recv_workqueue;
165 static struct workqueue_struct *send_workqueue;
166 
167 static struct hlist_head connection_hash[CONN_HASH_SIZE];
168 static DEFINE_MUTEX(connections_lock);
169 static struct kmem_cache *con_cache;
170 
171 static void process_recv_sockets(struct work_struct *work);
172 static void process_send_sockets(struct work_struct *work);
173 
174 
175 /* This is deliberately very simple because most clusters have simple
176    sequential nodeids, so we should be able to go straight to a connection
177    struct in the array */
nodeid_hash(int nodeid)178 static inline int nodeid_hash(int nodeid)
179 {
180 	return nodeid & (CONN_HASH_SIZE-1);
181 }
182 
__find_con(int nodeid)183 static struct connection *__find_con(int nodeid)
184 {
185 	int r;
186 	struct connection *con;
187 
188 	r = nodeid_hash(nodeid);
189 
190 	hlist_for_each_entry(con, &connection_hash[r], list) {
191 		if (con->nodeid == nodeid)
192 			return con;
193 	}
194 	return NULL;
195 }
196 
197 /*
198  * If 'allocation' is zero then we don't attempt to create a new
199  * connection structure for this node.
200  */
__nodeid2con(int nodeid,gfp_t alloc)201 static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
202 {
203 	struct connection *con = NULL;
204 	int r;
205 
206 	con = __find_con(nodeid);
207 	if (con || !alloc)
208 		return con;
209 
210 	con = kmem_cache_zalloc(con_cache, alloc);
211 	if (!con)
212 		return NULL;
213 
214 	r = nodeid_hash(nodeid);
215 	hlist_add_head(&con->list, &connection_hash[r]);
216 
217 	con->nodeid = nodeid;
218 	mutex_init(&con->sock_mutex);
219 	INIT_LIST_HEAD(&con->writequeue);
220 	spin_lock_init(&con->writequeue_lock);
221 	INIT_WORK(&con->swork, process_send_sockets);
222 	INIT_WORK(&con->rwork, process_recv_sockets);
223 
224 	/* Setup action pointers for child sockets */
225 	if (con->nodeid) {
226 		struct connection *zerocon = __find_con(0);
227 
228 		con->connect_action = zerocon->connect_action;
229 		if (!con->rx_action)
230 			con->rx_action = zerocon->rx_action;
231 	}
232 
233 	return con;
234 }
235 
236 /* Loop round all connections */
foreach_conn(void (* conn_func)(struct connection * c))237 static void foreach_conn(void (*conn_func)(struct connection *c))
238 {
239 	int i;
240 	struct hlist_node *n;
241 	struct connection *con;
242 
243 	for (i = 0; i < CONN_HASH_SIZE; i++) {
244 		hlist_for_each_entry_safe(con, n, &connection_hash[i], list)
245 			conn_func(con);
246 	}
247 }
248 
nodeid2con(int nodeid,gfp_t allocation)249 static struct connection *nodeid2con(int nodeid, gfp_t allocation)
250 {
251 	struct connection *con;
252 
253 	mutex_lock(&connections_lock);
254 	con = __nodeid2con(nodeid, allocation);
255 	mutex_unlock(&connections_lock);
256 
257 	return con;
258 }
259 
find_node_addr(int nodeid)260 static struct dlm_node_addr *find_node_addr(int nodeid)
261 {
262 	struct dlm_node_addr *na;
263 
264 	list_for_each_entry(na, &dlm_node_addrs, list) {
265 		if (na->nodeid == nodeid)
266 			return na;
267 	}
268 	return NULL;
269 }
270 
addr_compare(struct sockaddr_storage * x,struct sockaddr_storage * y)271 static int addr_compare(struct sockaddr_storage *x, struct sockaddr_storage *y)
272 {
273 	switch (x->ss_family) {
274 	case AF_INET: {
275 		struct sockaddr_in *sinx = (struct sockaddr_in *)x;
276 		struct sockaddr_in *siny = (struct sockaddr_in *)y;
277 		if (sinx->sin_addr.s_addr != siny->sin_addr.s_addr)
278 			return 0;
279 		if (sinx->sin_port != siny->sin_port)
280 			return 0;
281 		break;
282 	}
283 	case AF_INET6: {
284 		struct sockaddr_in6 *sinx = (struct sockaddr_in6 *)x;
285 		struct sockaddr_in6 *siny = (struct sockaddr_in6 *)y;
286 		if (!ipv6_addr_equal(&sinx->sin6_addr, &siny->sin6_addr))
287 			return 0;
288 		if (sinx->sin6_port != siny->sin6_port)
289 			return 0;
290 		break;
291 	}
292 	default:
293 		return 0;
294 	}
295 	return 1;
296 }
297 
nodeid_to_addr(int nodeid,struct sockaddr_storage * sas_out,struct sockaddr * sa_out,bool try_new_addr)298 static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
299 			  struct sockaddr *sa_out, bool try_new_addr)
300 {
301 	struct sockaddr_storage sas;
302 	struct dlm_node_addr *na;
303 
304 	if (!dlm_local_count)
305 		return -1;
306 
307 	spin_lock(&dlm_node_addrs_spin);
308 	na = find_node_addr(nodeid);
309 	if (na && na->addr_count) {
310 		memcpy(&sas, na->addr[na->curr_addr_index],
311 		       sizeof(struct sockaddr_storage));
312 
313 		if (try_new_addr) {
314 			na->curr_addr_index++;
315 			if (na->curr_addr_index == na->addr_count)
316 				na->curr_addr_index = 0;
317 		}
318 	}
319 	spin_unlock(&dlm_node_addrs_spin);
320 
321 	if (!na)
322 		return -EEXIST;
323 
324 	if (!na->addr_count)
325 		return -ENOENT;
326 
327 	if (sas_out)
328 		memcpy(sas_out, &sas, sizeof(struct sockaddr_storage));
329 
330 	if (!sa_out)
331 		return 0;
332 
333 	if (dlm_local_addr[0]->ss_family == AF_INET) {
334 		struct sockaddr_in *in4  = (struct sockaddr_in *) &sas;
335 		struct sockaddr_in *ret4 = (struct sockaddr_in *) sa_out;
336 		ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
337 	} else {
338 		struct sockaddr_in6 *in6  = (struct sockaddr_in6 *) &sas;
339 		struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) sa_out;
340 		ret6->sin6_addr = in6->sin6_addr;
341 	}
342 
343 	return 0;
344 }
345 
addr_to_nodeid(struct sockaddr_storage * addr,int * nodeid)346 static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid)
347 {
348 	struct dlm_node_addr *na;
349 	int rv = -EEXIST;
350 	int addr_i;
351 
352 	spin_lock(&dlm_node_addrs_spin);
353 	list_for_each_entry(na, &dlm_node_addrs, list) {
354 		if (!na->addr_count)
355 			continue;
356 
357 		for (addr_i = 0; addr_i < na->addr_count; addr_i++) {
358 			if (addr_compare(na->addr[addr_i], addr)) {
359 				*nodeid = na->nodeid;
360 				rv = 0;
361 				goto unlock;
362 			}
363 		}
364 	}
365 unlock:
366 	spin_unlock(&dlm_node_addrs_spin);
367 	return rv;
368 }
369 
dlm_lowcomms_addr(int nodeid,struct sockaddr_storage * addr,int len)370 int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len)
371 {
372 	struct sockaddr_storage *new_addr;
373 	struct dlm_node_addr *new_node, *na;
374 
375 	new_node = kzalloc(sizeof(struct dlm_node_addr), GFP_NOFS);
376 	if (!new_node)
377 		return -ENOMEM;
378 
379 	new_addr = kzalloc(sizeof(struct sockaddr_storage), GFP_NOFS);
380 	if (!new_addr) {
381 		kfree(new_node);
382 		return -ENOMEM;
383 	}
384 
385 	memcpy(new_addr, addr, len);
386 
387 	spin_lock(&dlm_node_addrs_spin);
388 	na = find_node_addr(nodeid);
389 	if (!na) {
390 		new_node->nodeid = nodeid;
391 		new_node->addr[0] = new_addr;
392 		new_node->addr_count = 1;
393 		list_add(&new_node->list, &dlm_node_addrs);
394 		spin_unlock(&dlm_node_addrs_spin);
395 		return 0;
396 	}
397 
398 	if (na->addr_count >= DLM_MAX_ADDR_COUNT) {
399 		spin_unlock(&dlm_node_addrs_spin);
400 		kfree(new_addr);
401 		kfree(new_node);
402 		return -ENOSPC;
403 	}
404 
405 	na->addr[na->addr_count++] = new_addr;
406 	spin_unlock(&dlm_node_addrs_spin);
407 	kfree(new_node);
408 	return 0;
409 }
410 
411 /* Data available on socket or listen socket received a connect */
lowcomms_data_ready(struct sock * sk)412 static void lowcomms_data_ready(struct sock *sk)
413 {
414 	struct connection *con;
415 
416 	read_lock_bh(&sk->sk_callback_lock);
417 	con = sock2con(sk);
418 	if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
419 		queue_work(recv_workqueue, &con->rwork);
420 	read_unlock_bh(&sk->sk_callback_lock);
421 }
422 
lowcomms_write_space(struct sock * sk)423 static void lowcomms_write_space(struct sock *sk)
424 {
425 	struct connection *con;
426 
427 	read_lock_bh(&sk->sk_callback_lock);
428 	con = sock2con(sk);
429 	if (!con)
430 		goto out;
431 
432 	clear_bit(SOCK_NOSPACE, &con->sock->flags);
433 
434 	if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
435 		con->sock->sk->sk_write_pending--;
436 		clear_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags);
437 	}
438 
439 	queue_work(send_workqueue, &con->swork);
440 out:
441 	read_unlock_bh(&sk->sk_callback_lock);
442 }
443 
lowcomms_connect_sock(struct connection * con)444 static inline void lowcomms_connect_sock(struct connection *con)
445 {
446 	if (test_bit(CF_CLOSE, &con->flags))
447 		return;
448 	queue_work(send_workqueue, &con->swork);
449 	cond_resched();
450 }
451 
lowcomms_state_change(struct sock * sk)452 static void lowcomms_state_change(struct sock *sk)
453 {
454 	/* SCTP layer is not calling sk_data_ready when the connection
455 	 * is done, so we catch the signal through here. Also, it
456 	 * doesn't switch socket state when entering shutdown, so we
457 	 * skip the write in that case.
458 	 */
459 	if (sk->sk_shutdown) {
460 		if (sk->sk_shutdown == RCV_SHUTDOWN)
461 			lowcomms_data_ready(sk);
462 	} else if (sk->sk_state == TCP_ESTABLISHED) {
463 		lowcomms_write_space(sk);
464 	}
465 }
466 
dlm_lowcomms_connect_node(int nodeid)467 int dlm_lowcomms_connect_node(int nodeid)
468 {
469 	struct connection *con;
470 
471 	if (nodeid == dlm_our_nodeid())
472 		return 0;
473 
474 	con = nodeid2con(nodeid, GFP_NOFS);
475 	if (!con)
476 		return -ENOMEM;
477 	lowcomms_connect_sock(con);
478 	return 0;
479 }
480 
lowcomms_error_report(struct sock * sk)481 static void lowcomms_error_report(struct sock *sk)
482 {
483 	struct connection *con;
484 	struct sockaddr_storage saddr;
485 	void (*orig_report)(struct sock *) = NULL;
486 
487 	read_lock_bh(&sk->sk_callback_lock);
488 	con = sock2con(sk);
489 	if (con == NULL)
490 		goto out;
491 
492 	orig_report = listen_sock.sk_error_report;
493 	if (con->sock == NULL ||
494 	    kernel_getpeername(con->sock, (struct sockaddr *)&saddr) < 0) {
495 		printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
496 				   "sending to node %d, port %d, "
497 				   "sk_err=%d/%d\n", dlm_our_nodeid(),
498 				   con->nodeid, dlm_config.ci_tcp_port,
499 				   sk->sk_err, sk->sk_err_soft);
500 	} else if (saddr.ss_family == AF_INET) {
501 		struct sockaddr_in *sin4 = (struct sockaddr_in *)&saddr;
502 
503 		printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
504 				   "sending to node %d at %pI4, port %d, "
505 				   "sk_err=%d/%d\n", dlm_our_nodeid(),
506 				   con->nodeid, &sin4->sin_addr.s_addr,
507 				   dlm_config.ci_tcp_port, sk->sk_err,
508 				   sk->sk_err_soft);
509 	} else {
510 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&saddr;
511 
512 		printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
513 				   "sending to node %d at %u.%u.%u.%u, "
514 				   "port %d, sk_err=%d/%d\n", dlm_our_nodeid(),
515 				   con->nodeid, sin6->sin6_addr.s6_addr32[0],
516 				   sin6->sin6_addr.s6_addr32[1],
517 				   sin6->sin6_addr.s6_addr32[2],
518 				   sin6->sin6_addr.s6_addr32[3],
519 				   dlm_config.ci_tcp_port, sk->sk_err,
520 				   sk->sk_err_soft);
521 	}
522 out:
523 	read_unlock_bh(&sk->sk_callback_lock);
524 	if (orig_report)
525 		orig_report(sk);
526 }
527 
528 /* Note: sk_callback_lock must be locked before calling this function. */
save_listen_callbacks(struct socket * sock)529 static void save_listen_callbacks(struct socket *sock)
530 {
531 	struct sock *sk = sock->sk;
532 
533 	listen_sock.sk_data_ready = sk->sk_data_ready;
534 	listen_sock.sk_state_change = sk->sk_state_change;
535 	listen_sock.sk_write_space = sk->sk_write_space;
536 	listen_sock.sk_error_report = sk->sk_error_report;
537 }
538 
restore_callbacks(struct socket * sock)539 static void restore_callbacks(struct socket *sock)
540 {
541 	struct sock *sk = sock->sk;
542 
543 	write_lock_bh(&sk->sk_callback_lock);
544 	sk->sk_user_data = NULL;
545 	sk->sk_data_ready = listen_sock.sk_data_ready;
546 	sk->sk_state_change = listen_sock.sk_state_change;
547 	sk->sk_write_space = listen_sock.sk_write_space;
548 	sk->sk_error_report = listen_sock.sk_error_report;
549 	write_unlock_bh(&sk->sk_callback_lock);
550 }
551 
552 /* Make a socket active */
add_sock(struct socket * sock,struct connection * con)553 static void add_sock(struct socket *sock, struct connection *con)
554 {
555 	struct sock *sk = sock->sk;
556 
557 	write_lock_bh(&sk->sk_callback_lock);
558 	con->sock = sock;
559 
560 	sk->sk_user_data = con;
561 	/* Install a data_ready callback */
562 	sk->sk_data_ready = lowcomms_data_ready;
563 	sk->sk_write_space = lowcomms_write_space;
564 	sk->sk_state_change = lowcomms_state_change;
565 	sk->sk_allocation = GFP_NOFS;
566 	sk->sk_error_report = lowcomms_error_report;
567 	write_unlock_bh(&sk->sk_callback_lock);
568 }
569 
570 /* Add the port number to an IPv6 or 4 sockaddr and return the address
571    length */
make_sockaddr(struct sockaddr_storage * saddr,uint16_t port,int * addr_len)572 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
573 			  int *addr_len)
574 {
575 	saddr->ss_family =  dlm_local_addr[0]->ss_family;
576 	if (saddr->ss_family == AF_INET) {
577 		struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
578 		in4_addr->sin_port = cpu_to_be16(port);
579 		*addr_len = sizeof(struct sockaddr_in);
580 		memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
581 	} else {
582 		struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
583 		in6_addr->sin6_port = cpu_to_be16(port);
584 		*addr_len = sizeof(struct sockaddr_in6);
585 	}
586 	memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
587 }
588 
589 /* Close a remote connection and tidy up */
close_connection(struct connection * con,bool and_other,bool tx,bool rx)590 static void close_connection(struct connection *con, bool and_other,
591 			     bool tx, bool rx)
592 {
593 	bool closing = test_and_set_bit(CF_CLOSING, &con->flags);
594 
595 	if (tx && !closing && cancel_work_sync(&con->swork)) {
596 		log_print("canceled swork for node %d", con->nodeid);
597 		clear_bit(CF_WRITE_PENDING, &con->flags);
598 	}
599 	if (rx && !closing && cancel_work_sync(&con->rwork)) {
600 		log_print("canceled rwork for node %d", con->nodeid);
601 		clear_bit(CF_READ_PENDING, &con->flags);
602 	}
603 
604 	mutex_lock(&con->sock_mutex);
605 	if (con->sock) {
606 		restore_callbacks(con->sock);
607 		sock_release(con->sock);
608 		con->sock = NULL;
609 	}
610 	if (con->othercon && and_other) {
611 		/* Will only re-enter once. */
612 		close_connection(con->othercon, false, tx, rx);
613 	}
614 	if (con->rx_page) {
615 		__free_page(con->rx_page);
616 		con->rx_page = NULL;
617 	}
618 
619 	con->retries = 0;
620 	mutex_unlock(&con->sock_mutex);
621 	clear_bit(CF_CLOSING, &con->flags);
622 }
623 
624 /* Data received from remote end */
receive_from_sock(struct connection * con)625 static int receive_from_sock(struct connection *con)
626 {
627 	int ret = 0;
628 	struct msghdr msg = {};
629 	struct kvec iov[2];
630 	unsigned len;
631 	int r;
632 	int call_again_soon = 0;
633 	int nvec;
634 
635 	mutex_lock(&con->sock_mutex);
636 
637 	if (con->sock == NULL) {
638 		ret = -EAGAIN;
639 		goto out_close;
640 	}
641 	if (con->nodeid == 0) {
642 		ret = -EINVAL;
643 		goto out_close;
644 	}
645 
646 	if (con->rx_page == NULL) {
647 		/*
648 		 * This doesn't need to be atomic, but I think it should
649 		 * improve performance if it is.
650 		 */
651 		con->rx_page = alloc_page(GFP_ATOMIC);
652 		if (con->rx_page == NULL)
653 			goto out_resched;
654 		cbuf_init(&con->cb, PAGE_SIZE);
655 	}
656 
657 	/*
658 	 * iov[0] is the bit of the circular buffer between the current end
659 	 * point (cb.base + cb.len) and the end of the buffer.
660 	 */
661 	iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
662 	iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
663 	iov[1].iov_len = 0;
664 	nvec = 1;
665 
666 	/*
667 	 * iov[1] is the bit of the circular buffer between the start of the
668 	 * buffer and the start of the currently used section (cb.base)
669 	 */
670 	if (cbuf_data(&con->cb) >= con->cb.base) {
671 		iov[0].iov_len = PAGE_SIZE - cbuf_data(&con->cb);
672 		iov[1].iov_len = con->cb.base;
673 		iov[1].iov_base = page_address(con->rx_page);
674 		nvec = 2;
675 	}
676 	len = iov[0].iov_len + iov[1].iov_len;
677 	iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, iov, nvec, len);
678 
679 	r = ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
680 	if (ret <= 0)
681 		goto out_close;
682 	else if (ret == len)
683 		call_again_soon = 1;
684 
685 	cbuf_add(&con->cb, ret);
686 	ret = dlm_process_incoming_buffer(con->nodeid,
687 					  page_address(con->rx_page),
688 					  con->cb.base, con->cb.len,
689 					  PAGE_SIZE);
690 	if (ret == -EBADMSG) {
691 		log_print("lowcomms: addr=%p, base=%u, len=%u, read=%d",
692 			  page_address(con->rx_page), con->cb.base,
693 			  con->cb.len, r);
694 	}
695 	if (ret < 0)
696 		goto out_close;
697 	cbuf_eat(&con->cb, ret);
698 
699 	if (cbuf_empty(&con->cb) && !call_again_soon) {
700 		__free_page(con->rx_page);
701 		con->rx_page = NULL;
702 	}
703 
704 	if (call_again_soon)
705 		goto out_resched;
706 	mutex_unlock(&con->sock_mutex);
707 	return 0;
708 
709 out_resched:
710 	if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
711 		queue_work(recv_workqueue, &con->rwork);
712 	mutex_unlock(&con->sock_mutex);
713 	return -EAGAIN;
714 
715 out_close:
716 	mutex_unlock(&con->sock_mutex);
717 	if (ret != -EAGAIN) {
718 		close_connection(con, true, true, false);
719 		/* Reconnect when there is something to send */
720 	}
721 	/* Don't return success if we really got EOF */
722 	if (ret == 0)
723 		ret = -EAGAIN;
724 
725 	return ret;
726 }
727 
728 /* Listening socket is busy, accept a connection */
tcp_accept_from_sock(struct connection * con)729 static int tcp_accept_from_sock(struct connection *con)
730 {
731 	int result;
732 	struct sockaddr_storage peeraddr;
733 	struct socket *newsock;
734 	int len;
735 	int nodeid;
736 	struct connection *newcon;
737 	struct connection *addcon;
738 
739 	mutex_lock(&connections_lock);
740 	if (!dlm_allow_conn) {
741 		mutex_unlock(&connections_lock);
742 		return -1;
743 	}
744 	mutex_unlock(&connections_lock);
745 
746 	mutex_lock_nested(&con->sock_mutex, 0);
747 
748 	if (!con->sock) {
749 		mutex_unlock(&con->sock_mutex);
750 		return -ENOTCONN;
751 	}
752 
753 	result = kernel_accept(con->sock, &newsock, O_NONBLOCK);
754 	if (result < 0)
755 		goto accept_err;
756 
757 	/* Get the connected socket's peer */
758 	memset(&peeraddr, 0, sizeof(peeraddr));
759 	len = newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr, 2);
760 	if (len < 0) {
761 		result = -ECONNABORTED;
762 		goto accept_err;
763 	}
764 
765 	/* Get the new node's NODEID */
766 	make_sockaddr(&peeraddr, 0, &len);
767 	if (addr_to_nodeid(&peeraddr, &nodeid)) {
768 		unsigned char *b=(unsigned char *)&peeraddr;
769 		log_print("connect from non cluster node");
770 		print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
771 				     b, sizeof(struct sockaddr_storage));
772 		sock_release(newsock);
773 		mutex_unlock(&con->sock_mutex);
774 		return -1;
775 	}
776 
777 	log_print("got connection from %d", nodeid);
778 
779 	/*  Check to see if we already have a connection to this node. This
780 	 *  could happen if the two nodes initiate a connection at roughly
781 	 *  the same time and the connections cross on the wire.
782 	 *  In this case we store the incoming one in "othercon"
783 	 */
784 	newcon = nodeid2con(nodeid, GFP_NOFS);
785 	if (!newcon) {
786 		result = -ENOMEM;
787 		goto accept_err;
788 	}
789 	mutex_lock_nested(&newcon->sock_mutex, 1);
790 	if (newcon->sock) {
791 		struct connection *othercon = newcon->othercon;
792 
793 		if (!othercon) {
794 			othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
795 			if (!othercon) {
796 				log_print("failed to allocate incoming socket");
797 				mutex_unlock(&newcon->sock_mutex);
798 				result = -ENOMEM;
799 				goto accept_err;
800 			}
801 			othercon->nodeid = nodeid;
802 			othercon->rx_action = receive_from_sock;
803 			mutex_init(&othercon->sock_mutex);
804 			INIT_LIST_HEAD(&othercon->writequeue);
805 			spin_lock_init(&othercon->writequeue_lock);
806 			INIT_WORK(&othercon->swork, process_send_sockets);
807 			INIT_WORK(&othercon->rwork, process_recv_sockets);
808 			set_bit(CF_IS_OTHERCON, &othercon->flags);
809 		}
810 		mutex_lock_nested(&othercon->sock_mutex, 2);
811 		if (!othercon->sock) {
812 			newcon->othercon = othercon;
813 			add_sock(newsock, othercon);
814 			addcon = othercon;
815 			mutex_unlock(&othercon->sock_mutex);
816 		}
817 		else {
818 			printk("Extra connection from node %d attempted\n", nodeid);
819 			result = -EAGAIN;
820 			mutex_unlock(&othercon->sock_mutex);
821 			mutex_unlock(&newcon->sock_mutex);
822 			goto accept_err;
823 		}
824 	}
825 	else {
826 		newcon->rx_action = receive_from_sock;
827 		/* accept copies the sk after we've saved the callbacks, so we
828 		   don't want to save them a second time or comm errors will
829 		   result in calling sk_error_report recursively. */
830 		add_sock(newsock, newcon);
831 		addcon = newcon;
832 	}
833 
834 	mutex_unlock(&newcon->sock_mutex);
835 
836 	/*
837 	 * Add it to the active queue in case we got data
838 	 * between processing the accept adding the socket
839 	 * to the read_sockets list
840 	 */
841 	if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
842 		queue_work(recv_workqueue, &addcon->rwork);
843 	mutex_unlock(&con->sock_mutex);
844 
845 	return 0;
846 
847 accept_err:
848 	mutex_unlock(&con->sock_mutex);
849 	if (newsock)
850 		sock_release(newsock);
851 
852 	if (result != -EAGAIN)
853 		log_print("error accepting connection from node: %d", result);
854 	return result;
855 }
856 
sctp_accept_from_sock(struct connection * con)857 static int sctp_accept_from_sock(struct connection *con)
858 {
859 	/* Check that the new node is in the lockspace */
860 	struct sctp_prim prim;
861 	int nodeid;
862 	int prim_len, ret;
863 	int addr_len;
864 	struct connection *newcon;
865 	struct connection *addcon;
866 	struct socket *newsock;
867 
868 	mutex_lock(&connections_lock);
869 	if (!dlm_allow_conn) {
870 		mutex_unlock(&connections_lock);
871 		return -1;
872 	}
873 	mutex_unlock(&connections_lock);
874 
875 	mutex_lock_nested(&con->sock_mutex, 0);
876 
877 	ret = kernel_accept(con->sock, &newsock, O_NONBLOCK);
878 	if (ret < 0)
879 		goto accept_err;
880 
881 	memset(&prim, 0, sizeof(struct sctp_prim));
882 	prim_len = sizeof(struct sctp_prim);
883 
884 	ret = kernel_getsockopt(newsock, IPPROTO_SCTP, SCTP_PRIMARY_ADDR,
885 				(char *)&prim, &prim_len);
886 	if (ret < 0) {
887 		log_print("getsockopt/sctp_primary_addr failed: %d", ret);
888 		goto accept_err;
889 	}
890 
891 	make_sockaddr(&prim.ssp_addr, 0, &addr_len);
892 	ret = addr_to_nodeid(&prim.ssp_addr, &nodeid);
893 	if (ret) {
894 		unsigned char *b = (unsigned char *)&prim.ssp_addr;
895 
896 		log_print("reject connect from unknown addr");
897 		print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
898 				     b, sizeof(struct sockaddr_storage));
899 		goto accept_err;
900 	}
901 
902 	newcon = nodeid2con(nodeid, GFP_NOFS);
903 	if (!newcon) {
904 		ret = -ENOMEM;
905 		goto accept_err;
906 	}
907 
908 	mutex_lock_nested(&newcon->sock_mutex, 1);
909 
910 	if (newcon->sock) {
911 		struct connection *othercon = newcon->othercon;
912 
913 		if (!othercon) {
914 			othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
915 			if (!othercon) {
916 				log_print("failed to allocate incoming socket");
917 				mutex_unlock(&newcon->sock_mutex);
918 				ret = -ENOMEM;
919 				goto accept_err;
920 			}
921 			othercon->nodeid = nodeid;
922 			othercon->rx_action = receive_from_sock;
923 			mutex_init(&othercon->sock_mutex);
924 			INIT_LIST_HEAD(&othercon->writequeue);
925 			spin_lock_init(&othercon->writequeue_lock);
926 			INIT_WORK(&othercon->swork, process_send_sockets);
927 			INIT_WORK(&othercon->rwork, process_recv_sockets);
928 			set_bit(CF_IS_OTHERCON, &othercon->flags);
929 		}
930 		mutex_lock_nested(&othercon->sock_mutex, 2);
931 		if (!othercon->sock) {
932 			newcon->othercon = othercon;
933 			add_sock(newsock, othercon);
934 			addcon = othercon;
935 			mutex_unlock(&othercon->sock_mutex);
936 		} else {
937 			printk("Extra connection from node %d attempted\n", nodeid);
938 			ret = -EAGAIN;
939 			mutex_unlock(&othercon->sock_mutex);
940 			mutex_unlock(&newcon->sock_mutex);
941 			goto accept_err;
942 		}
943 	} else {
944 		newcon->rx_action = receive_from_sock;
945 		add_sock(newsock, newcon);
946 		addcon = newcon;
947 	}
948 
949 	log_print("connected to %d", nodeid);
950 
951 	mutex_unlock(&newcon->sock_mutex);
952 
953 	/*
954 	 * Add it to the active queue in case we got data
955 	 * between processing the accept adding the socket
956 	 * to the read_sockets list
957 	 */
958 	if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
959 		queue_work(recv_workqueue, &addcon->rwork);
960 	mutex_unlock(&con->sock_mutex);
961 
962 	return 0;
963 
964 accept_err:
965 	mutex_unlock(&con->sock_mutex);
966 	if (newsock)
967 		sock_release(newsock);
968 	if (ret != -EAGAIN)
969 		log_print("error accepting connection from node: %d", ret);
970 
971 	return ret;
972 }
973 
free_entry(struct writequeue_entry * e)974 static void free_entry(struct writequeue_entry *e)
975 {
976 	__free_page(e->page);
977 	kfree(e);
978 }
979 
980 /*
981  * writequeue_entry_complete - try to delete and free write queue entry
982  * @e: write queue entry to try to delete
983  * @completed: bytes completed
984  *
985  * writequeue_lock must be held.
986  */
writequeue_entry_complete(struct writequeue_entry * e,int completed)987 static void writequeue_entry_complete(struct writequeue_entry *e, int completed)
988 {
989 	e->offset += completed;
990 	e->len -= completed;
991 
992 	if (e->len == 0 && e->users == 0) {
993 		list_del(&e->list);
994 		free_entry(e);
995 	}
996 }
997 
998 /*
999  * sctp_bind_addrs - bind a SCTP socket to all our addresses
1000  */
sctp_bind_addrs(struct connection * con,uint16_t port)1001 static int sctp_bind_addrs(struct connection *con, uint16_t port)
1002 {
1003 	struct sockaddr_storage localaddr;
1004 	int i, addr_len, result = 0;
1005 
1006 	for (i = 0; i < dlm_local_count; i++) {
1007 		memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
1008 		make_sockaddr(&localaddr, port, &addr_len);
1009 
1010 		if (!i)
1011 			result = kernel_bind(con->sock,
1012 					     (struct sockaddr *)&localaddr,
1013 					     addr_len);
1014 		else
1015 			result = kernel_setsockopt(con->sock, SOL_SCTP,
1016 						   SCTP_SOCKOPT_BINDX_ADD,
1017 						   (char *)&localaddr, addr_len);
1018 
1019 		if (result < 0) {
1020 			log_print("Can't bind to %d addr number %d, %d.\n",
1021 				  port, i + 1, result);
1022 			break;
1023 		}
1024 	}
1025 	return result;
1026 }
1027 
1028 /* Initiate an SCTP association.
1029    This is a special case of send_to_sock() in that we don't yet have a
1030    peeled-off socket for this association, so we use the listening socket
1031    and add the primary IP address of the remote node.
1032  */
sctp_connect_to_sock(struct connection * con)1033 static void sctp_connect_to_sock(struct connection *con)
1034 {
1035 	struct sockaddr_storage daddr;
1036 	int one = 1;
1037 	int result;
1038 	int addr_len;
1039 	struct socket *sock;
1040 	struct timeval tv = { .tv_sec = 5, .tv_usec = 0 };
1041 
1042 	if (con->nodeid == 0) {
1043 		log_print("attempt to connect sock 0 foiled");
1044 		return;
1045 	}
1046 
1047 	mutex_lock(&con->sock_mutex);
1048 
1049 	/* Some odd races can cause double-connects, ignore them */
1050 	if (con->retries++ > MAX_CONNECT_RETRIES)
1051 		goto out;
1052 
1053 	if (con->sock) {
1054 		log_print("node %d already connected.", con->nodeid);
1055 		goto out;
1056 	}
1057 
1058 	memset(&daddr, 0, sizeof(daddr));
1059 	result = nodeid_to_addr(con->nodeid, &daddr, NULL, true);
1060 	if (result < 0) {
1061 		log_print("no address for nodeid %d", con->nodeid);
1062 		goto out;
1063 	}
1064 
1065 	/* Create a socket to communicate with */
1066 	result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1067 				  SOCK_STREAM, IPPROTO_SCTP, &sock);
1068 	if (result < 0)
1069 		goto socket_err;
1070 
1071 	con->rx_action = receive_from_sock;
1072 	con->connect_action = sctp_connect_to_sock;
1073 	add_sock(sock, con);
1074 
1075 	/* Bind to all addresses. */
1076 	if (sctp_bind_addrs(con, 0))
1077 		goto bind_err;
1078 
1079 	make_sockaddr(&daddr, dlm_config.ci_tcp_port, &addr_len);
1080 
1081 	log_print("connecting to %d", con->nodeid);
1082 
1083 	/* Turn off Nagle's algorithm */
1084 	kernel_setsockopt(sock, SOL_SCTP, SCTP_NODELAY, (char *)&one,
1085 			  sizeof(one));
1086 
1087 	/*
1088 	 * Make sock->ops->connect() function return in specified time,
1089 	 * since O_NONBLOCK argument in connect() function does not work here,
1090 	 * then, we should restore the default value of this attribute.
1091 	 */
1092 	kernel_setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, (char *)&tv,
1093 			  sizeof(tv));
1094 	result = sock->ops->connect(sock, (struct sockaddr *)&daddr, addr_len,
1095 				   0);
1096 	memset(&tv, 0, sizeof(tv));
1097 	kernel_setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, (char *)&tv,
1098 			  sizeof(tv));
1099 
1100 	if (result == -EINPROGRESS)
1101 		result = 0;
1102 	if (result == 0)
1103 		goto out;
1104 
1105 bind_err:
1106 	con->sock = NULL;
1107 	sock_release(sock);
1108 
1109 socket_err:
1110 	/*
1111 	 * Some errors are fatal and this list might need adjusting. For other
1112 	 * errors we try again until the max number of retries is reached.
1113 	 */
1114 	if (result != -EHOSTUNREACH &&
1115 	    result != -ENETUNREACH &&
1116 	    result != -ENETDOWN &&
1117 	    result != -EINVAL &&
1118 	    result != -EPROTONOSUPPORT) {
1119 		log_print("connect %d try %d error %d", con->nodeid,
1120 			  con->retries, result);
1121 		mutex_unlock(&con->sock_mutex);
1122 		msleep(1000);
1123 		lowcomms_connect_sock(con);
1124 		return;
1125 	}
1126 
1127 out:
1128 	mutex_unlock(&con->sock_mutex);
1129 }
1130 
1131 /* Connect a new socket to its peer */
tcp_connect_to_sock(struct connection * con)1132 static void tcp_connect_to_sock(struct connection *con)
1133 {
1134 	struct sockaddr_storage saddr, src_addr;
1135 	int addr_len;
1136 	struct socket *sock = NULL;
1137 	int one = 1;
1138 	int result;
1139 
1140 	if (con->nodeid == 0) {
1141 		log_print("attempt to connect sock 0 foiled");
1142 		return;
1143 	}
1144 
1145 	mutex_lock(&con->sock_mutex);
1146 	if (con->retries++ > MAX_CONNECT_RETRIES)
1147 		goto out;
1148 
1149 	/* Some odd races can cause double-connects, ignore them */
1150 	if (con->sock)
1151 		goto out;
1152 
1153 	/* Create a socket to communicate with */
1154 	result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1155 				  SOCK_STREAM, IPPROTO_TCP, &sock);
1156 	if (result < 0)
1157 		goto out_err;
1158 
1159 	memset(&saddr, 0, sizeof(saddr));
1160 	result = nodeid_to_addr(con->nodeid, &saddr, NULL, false);
1161 	if (result < 0) {
1162 		log_print("no address for nodeid %d", con->nodeid);
1163 		goto out_err;
1164 	}
1165 
1166 	con->rx_action = receive_from_sock;
1167 	con->connect_action = tcp_connect_to_sock;
1168 	add_sock(sock, con);
1169 
1170 	/* Bind to our cluster-known address connecting to avoid
1171 	   routing problems */
1172 	memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
1173 	make_sockaddr(&src_addr, 0, &addr_len);
1174 	result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
1175 				 addr_len);
1176 	if (result < 0) {
1177 		log_print("could not bind for connect: %d", result);
1178 		/* This *may* not indicate a critical error */
1179 	}
1180 
1181 	make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
1182 
1183 	log_print("connecting to %d", con->nodeid);
1184 
1185 	/* Turn off Nagle's algorithm */
1186 	kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
1187 			  sizeof(one));
1188 
1189 	result = sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
1190 				   O_NONBLOCK);
1191 	if (result == -EINPROGRESS)
1192 		result = 0;
1193 	if (result == 0)
1194 		goto out;
1195 
1196 out_err:
1197 	if (con->sock) {
1198 		sock_release(con->sock);
1199 		con->sock = NULL;
1200 	} else if (sock) {
1201 		sock_release(sock);
1202 	}
1203 	/*
1204 	 * Some errors are fatal and this list might need adjusting. For other
1205 	 * errors we try again until the max number of retries is reached.
1206 	 */
1207 	if (result != -EHOSTUNREACH &&
1208 	    result != -ENETUNREACH &&
1209 	    result != -ENETDOWN &&
1210 	    result != -EINVAL &&
1211 	    result != -EPROTONOSUPPORT) {
1212 		log_print("connect %d try %d error %d", con->nodeid,
1213 			  con->retries, result);
1214 		mutex_unlock(&con->sock_mutex);
1215 		msleep(1000);
1216 		lowcomms_connect_sock(con);
1217 		return;
1218 	}
1219 out:
1220 	mutex_unlock(&con->sock_mutex);
1221 	return;
1222 }
1223 
tcp_create_listen_sock(struct connection * con,struct sockaddr_storage * saddr)1224 static struct socket *tcp_create_listen_sock(struct connection *con,
1225 					     struct sockaddr_storage *saddr)
1226 {
1227 	struct socket *sock = NULL;
1228 	int result = 0;
1229 	int one = 1;
1230 	int addr_len;
1231 
1232 	if (dlm_local_addr[0]->ss_family == AF_INET)
1233 		addr_len = sizeof(struct sockaddr_in);
1234 	else
1235 		addr_len = sizeof(struct sockaddr_in6);
1236 
1237 	/* Create a socket to communicate with */
1238 	result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1239 				  SOCK_STREAM, IPPROTO_TCP, &sock);
1240 	if (result < 0) {
1241 		log_print("Can't create listening comms socket");
1242 		goto create_out;
1243 	}
1244 
1245 	/* Turn off Nagle's algorithm */
1246 	kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
1247 			  sizeof(one));
1248 
1249 	result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
1250 				   (char *)&one, sizeof(one));
1251 
1252 	if (result < 0) {
1253 		log_print("Failed to set SO_REUSEADDR on socket: %d", result);
1254 	}
1255 	write_lock_bh(&sock->sk->sk_callback_lock);
1256 	sock->sk->sk_user_data = con;
1257 	save_listen_callbacks(sock);
1258 	con->rx_action = tcp_accept_from_sock;
1259 	con->connect_action = tcp_connect_to_sock;
1260 	write_unlock_bh(&sock->sk->sk_callback_lock);
1261 
1262 	/* Bind to our port */
1263 	make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
1264 	result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
1265 	if (result < 0) {
1266 		log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
1267 		sock_release(sock);
1268 		sock = NULL;
1269 		con->sock = NULL;
1270 		goto create_out;
1271 	}
1272 	result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
1273 				 (char *)&one, sizeof(one));
1274 	if (result < 0) {
1275 		log_print("Set keepalive failed: %d", result);
1276 	}
1277 
1278 	result = sock->ops->listen(sock, 5);
1279 	if (result < 0) {
1280 		log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
1281 		sock_release(sock);
1282 		sock = NULL;
1283 		goto create_out;
1284 	}
1285 
1286 create_out:
1287 	return sock;
1288 }
1289 
1290 /* Get local addresses */
init_local(void)1291 static void init_local(void)
1292 {
1293 	struct sockaddr_storage sas, *addr;
1294 	int i;
1295 
1296 	dlm_local_count = 0;
1297 	for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) {
1298 		if (dlm_our_addr(&sas, i))
1299 			break;
1300 
1301 		addr = kmemdup(&sas, sizeof(*addr), GFP_NOFS);
1302 		if (!addr)
1303 			break;
1304 		dlm_local_addr[dlm_local_count++] = addr;
1305 	}
1306 }
1307 
1308 /* Initialise SCTP socket and bind to all interfaces */
sctp_listen_for_all(void)1309 static int sctp_listen_for_all(void)
1310 {
1311 	struct socket *sock = NULL;
1312 	int result = -EINVAL;
1313 	struct connection *con = nodeid2con(0, GFP_NOFS);
1314 	int bufsize = NEEDED_RMEM;
1315 	int one = 1;
1316 
1317 	if (!con)
1318 		return -ENOMEM;
1319 
1320 	log_print("Using SCTP for communications");
1321 
1322 	result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1323 				  SOCK_STREAM, IPPROTO_SCTP, &sock);
1324 	if (result < 0) {
1325 		log_print("Can't create comms socket, check SCTP is loaded");
1326 		goto out;
1327 	}
1328 
1329 	result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE,
1330 				 (char *)&bufsize, sizeof(bufsize));
1331 	if (result)
1332 		log_print("Error increasing buffer space on socket %d", result);
1333 
1334 	result = kernel_setsockopt(sock, SOL_SCTP, SCTP_NODELAY, (char *)&one,
1335 				   sizeof(one));
1336 	if (result < 0)
1337 		log_print("Could not set SCTP NODELAY error %d\n", result);
1338 
1339 	write_lock_bh(&sock->sk->sk_callback_lock);
1340 	/* Init con struct */
1341 	sock->sk->sk_user_data = con;
1342 	save_listen_callbacks(sock);
1343 	con->sock = sock;
1344 	con->sock->sk->sk_data_ready = lowcomms_data_ready;
1345 	con->rx_action = sctp_accept_from_sock;
1346 	con->connect_action = sctp_connect_to_sock;
1347 
1348 	write_unlock_bh(&sock->sk->sk_callback_lock);
1349 
1350 	/* Bind to all addresses. */
1351 	if (sctp_bind_addrs(con, dlm_config.ci_tcp_port))
1352 		goto create_delsock;
1353 
1354 	result = sock->ops->listen(sock, 5);
1355 	if (result < 0) {
1356 		log_print("Can't set socket listening");
1357 		goto create_delsock;
1358 	}
1359 
1360 	return 0;
1361 
1362 create_delsock:
1363 	sock_release(sock);
1364 	con->sock = NULL;
1365 out:
1366 	return result;
1367 }
1368 
tcp_listen_for_all(void)1369 static int tcp_listen_for_all(void)
1370 {
1371 	struct socket *sock = NULL;
1372 	struct connection *con = nodeid2con(0, GFP_NOFS);
1373 	int result = -EINVAL;
1374 
1375 	if (!con)
1376 		return -ENOMEM;
1377 
1378 	/* We don't support multi-homed hosts */
1379 	if (dlm_local_addr[1] != NULL) {
1380 		log_print("TCP protocol can't handle multi-homed hosts, "
1381 			  "try SCTP");
1382 		return -EINVAL;
1383 	}
1384 
1385 	log_print("Using TCP for communications");
1386 
1387 	sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
1388 	if (sock) {
1389 		add_sock(sock, con);
1390 		result = 0;
1391 	}
1392 	else {
1393 		result = -EADDRINUSE;
1394 	}
1395 
1396 	return result;
1397 }
1398 
1399 
1400 
new_writequeue_entry(struct connection * con,gfp_t allocation)1401 static struct writequeue_entry *new_writequeue_entry(struct connection *con,
1402 						     gfp_t allocation)
1403 {
1404 	struct writequeue_entry *entry;
1405 
1406 	entry = kmalloc(sizeof(struct writequeue_entry), allocation);
1407 	if (!entry)
1408 		return NULL;
1409 
1410 	entry->page = alloc_page(allocation);
1411 	if (!entry->page) {
1412 		kfree(entry);
1413 		return NULL;
1414 	}
1415 
1416 	entry->offset = 0;
1417 	entry->len = 0;
1418 	entry->end = 0;
1419 	entry->users = 0;
1420 	entry->con = con;
1421 
1422 	return entry;
1423 }
1424 
dlm_lowcomms_get_buffer(int nodeid,int len,gfp_t allocation,char ** ppc)1425 void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
1426 {
1427 	struct connection *con;
1428 	struct writequeue_entry *e;
1429 	int offset = 0;
1430 
1431 	con = nodeid2con(nodeid, allocation);
1432 	if (!con)
1433 		return NULL;
1434 
1435 	spin_lock(&con->writequeue_lock);
1436 	e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
1437 	if ((&e->list == &con->writequeue) ||
1438 	    (PAGE_SIZE - e->end < len)) {
1439 		e = NULL;
1440 	} else {
1441 		offset = e->end;
1442 		e->end += len;
1443 		e->users++;
1444 	}
1445 	spin_unlock(&con->writequeue_lock);
1446 
1447 	if (e) {
1448 	got_one:
1449 		*ppc = page_address(e->page) + offset;
1450 		return e;
1451 	}
1452 
1453 	e = new_writequeue_entry(con, allocation);
1454 	if (e) {
1455 		spin_lock(&con->writequeue_lock);
1456 		offset = e->end;
1457 		e->end += len;
1458 		e->users++;
1459 		list_add_tail(&e->list, &con->writequeue);
1460 		spin_unlock(&con->writequeue_lock);
1461 		goto got_one;
1462 	}
1463 	return NULL;
1464 }
1465 
dlm_lowcomms_commit_buffer(void * mh)1466 void dlm_lowcomms_commit_buffer(void *mh)
1467 {
1468 	struct writequeue_entry *e = (struct writequeue_entry *)mh;
1469 	struct connection *con = e->con;
1470 	int users;
1471 
1472 	spin_lock(&con->writequeue_lock);
1473 	users = --e->users;
1474 	if (users)
1475 		goto out;
1476 	e->len = e->end - e->offset;
1477 	spin_unlock(&con->writequeue_lock);
1478 
1479 	queue_work(send_workqueue, &con->swork);
1480 	return;
1481 
1482 out:
1483 	spin_unlock(&con->writequeue_lock);
1484 	return;
1485 }
1486 
1487 /* Send a message */
send_to_sock(struct connection * con)1488 static void send_to_sock(struct connection *con)
1489 {
1490 	int ret = 0;
1491 	const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1492 	struct writequeue_entry *e;
1493 	int len, offset;
1494 	int count = 0;
1495 
1496 	mutex_lock(&con->sock_mutex);
1497 	if (con->sock == NULL)
1498 		goto out_connect;
1499 
1500 	spin_lock(&con->writequeue_lock);
1501 	for (;;) {
1502 		e = list_entry(con->writequeue.next, struct writequeue_entry,
1503 			       list);
1504 		if ((struct list_head *) e == &con->writequeue)
1505 			break;
1506 
1507 		len = e->len;
1508 		offset = e->offset;
1509 		BUG_ON(len == 0 && e->users == 0);
1510 		spin_unlock(&con->writequeue_lock);
1511 
1512 		ret = 0;
1513 		if (len) {
1514 			ret = kernel_sendpage(con->sock, e->page, offset, len,
1515 					      msg_flags);
1516 			if (ret == -EAGAIN || ret == 0) {
1517 				if (ret == -EAGAIN &&
1518 				    test_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags) &&
1519 				    !test_and_set_bit(CF_APP_LIMITED, &con->flags)) {
1520 					/* Notify TCP that we're limited by the
1521 					 * application window size.
1522 					 */
1523 					set_bit(SOCK_NOSPACE, &con->sock->flags);
1524 					con->sock->sk->sk_write_pending++;
1525 				}
1526 				cond_resched();
1527 				goto out;
1528 			} else if (ret < 0)
1529 				goto send_error;
1530 		}
1531 
1532 		/* Don't starve people filling buffers */
1533 		if (++count >= MAX_SEND_MSG_COUNT) {
1534 			cond_resched();
1535 			count = 0;
1536 		}
1537 
1538 		spin_lock(&con->writequeue_lock);
1539 		writequeue_entry_complete(e, ret);
1540 	}
1541 	spin_unlock(&con->writequeue_lock);
1542 out:
1543 	mutex_unlock(&con->sock_mutex);
1544 	return;
1545 
1546 send_error:
1547 	mutex_unlock(&con->sock_mutex);
1548 	close_connection(con, true, false, true);
1549 	/* Requeue the send work. When the work daemon runs again, it will try
1550 	   a new connection, then call this function again. */
1551 	queue_work(send_workqueue, &con->swork);
1552 	return;
1553 
1554 out_connect:
1555 	mutex_unlock(&con->sock_mutex);
1556 	queue_work(send_workqueue, &con->swork);
1557 	cond_resched();
1558 }
1559 
clean_one_writequeue(struct connection * con)1560 static void clean_one_writequeue(struct connection *con)
1561 {
1562 	struct writequeue_entry *e, *safe;
1563 
1564 	spin_lock(&con->writequeue_lock);
1565 	list_for_each_entry_safe(e, safe, &con->writequeue, list) {
1566 		list_del(&e->list);
1567 		free_entry(e);
1568 	}
1569 	spin_unlock(&con->writequeue_lock);
1570 }
1571 
1572 /* Called from recovery when it knows that a node has
1573    left the cluster */
dlm_lowcomms_close(int nodeid)1574 int dlm_lowcomms_close(int nodeid)
1575 {
1576 	struct connection *con;
1577 	struct dlm_node_addr *na;
1578 
1579 	log_print("closing connection to node %d", nodeid);
1580 	con = nodeid2con(nodeid, 0);
1581 	if (con) {
1582 		set_bit(CF_CLOSE, &con->flags);
1583 		close_connection(con, true, true, true);
1584 		clean_one_writequeue(con);
1585 	}
1586 
1587 	spin_lock(&dlm_node_addrs_spin);
1588 	na = find_node_addr(nodeid);
1589 	if (na) {
1590 		list_del(&na->list);
1591 		while (na->addr_count--)
1592 			kfree(na->addr[na->addr_count]);
1593 		kfree(na);
1594 	}
1595 	spin_unlock(&dlm_node_addrs_spin);
1596 
1597 	return 0;
1598 }
1599 
1600 /* Receive workqueue function */
process_recv_sockets(struct work_struct * work)1601 static void process_recv_sockets(struct work_struct *work)
1602 {
1603 	struct connection *con = container_of(work, struct connection, rwork);
1604 	int err;
1605 
1606 	clear_bit(CF_READ_PENDING, &con->flags);
1607 	do {
1608 		err = con->rx_action(con);
1609 	} while (!err);
1610 }
1611 
1612 /* Send workqueue function */
process_send_sockets(struct work_struct * work)1613 static void process_send_sockets(struct work_struct *work)
1614 {
1615 	struct connection *con = container_of(work, struct connection, swork);
1616 
1617 	clear_bit(CF_WRITE_PENDING, &con->flags);
1618 	if (con->sock == NULL) /* not mutex protected so check it inside too */
1619 		con->connect_action(con);
1620 	if (!list_empty(&con->writequeue))
1621 		send_to_sock(con);
1622 }
1623 
1624 
1625 /* Discard all entries on the write queues */
clean_writequeues(void)1626 static void clean_writequeues(void)
1627 {
1628 	foreach_conn(clean_one_writequeue);
1629 }
1630 
work_stop(void)1631 static void work_stop(void)
1632 {
1633 	if (recv_workqueue)
1634 		destroy_workqueue(recv_workqueue);
1635 	if (send_workqueue)
1636 		destroy_workqueue(send_workqueue);
1637 }
1638 
work_start(void)1639 static int work_start(void)
1640 {
1641 	recv_workqueue = alloc_workqueue("dlm_recv",
1642 					 WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1643 	if (!recv_workqueue) {
1644 		log_print("can't start dlm_recv");
1645 		return -ENOMEM;
1646 	}
1647 
1648 	send_workqueue = alloc_workqueue("dlm_send",
1649 					 WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1650 	if (!send_workqueue) {
1651 		log_print("can't start dlm_send");
1652 		destroy_workqueue(recv_workqueue);
1653 		return -ENOMEM;
1654 	}
1655 
1656 	return 0;
1657 }
1658 
_stop_conn(struct connection * con,bool and_other)1659 static void _stop_conn(struct connection *con, bool and_other)
1660 {
1661 	mutex_lock(&con->sock_mutex);
1662 	set_bit(CF_CLOSE, &con->flags);
1663 	set_bit(CF_READ_PENDING, &con->flags);
1664 	set_bit(CF_WRITE_PENDING, &con->flags);
1665 	if (con->sock && con->sock->sk) {
1666 		write_lock_bh(&con->sock->sk->sk_callback_lock);
1667 		con->sock->sk->sk_user_data = NULL;
1668 		write_unlock_bh(&con->sock->sk->sk_callback_lock);
1669 	}
1670 	if (con->othercon && and_other)
1671 		_stop_conn(con->othercon, false);
1672 	mutex_unlock(&con->sock_mutex);
1673 }
1674 
stop_conn(struct connection * con)1675 static void stop_conn(struct connection *con)
1676 {
1677 	_stop_conn(con, true);
1678 }
1679 
free_conn(struct connection * con)1680 static void free_conn(struct connection *con)
1681 {
1682 	close_connection(con, true, true, true);
1683 	if (con->othercon)
1684 		kmem_cache_free(con_cache, con->othercon);
1685 	hlist_del(&con->list);
1686 	kmem_cache_free(con_cache, con);
1687 }
1688 
work_flush(void)1689 static void work_flush(void)
1690 {
1691 	int ok;
1692 	int i;
1693 	struct hlist_node *n;
1694 	struct connection *con;
1695 
1696 	if (recv_workqueue)
1697 		flush_workqueue(recv_workqueue);
1698 	if (send_workqueue)
1699 		flush_workqueue(send_workqueue);
1700 	do {
1701 		ok = 1;
1702 		foreach_conn(stop_conn);
1703 		if (recv_workqueue)
1704 			flush_workqueue(recv_workqueue);
1705 		if (send_workqueue)
1706 			flush_workqueue(send_workqueue);
1707 		for (i = 0; i < CONN_HASH_SIZE && ok; i++) {
1708 			hlist_for_each_entry_safe(con, n,
1709 						  &connection_hash[i], list) {
1710 				ok &= test_bit(CF_READ_PENDING, &con->flags);
1711 				ok &= test_bit(CF_WRITE_PENDING, &con->flags);
1712 				if (con->othercon) {
1713 					ok &= test_bit(CF_READ_PENDING,
1714 						       &con->othercon->flags);
1715 					ok &= test_bit(CF_WRITE_PENDING,
1716 						       &con->othercon->flags);
1717 				}
1718 			}
1719 		}
1720 	} while (!ok);
1721 }
1722 
dlm_lowcomms_stop(void)1723 void dlm_lowcomms_stop(void)
1724 {
1725 	/* Set all the flags to prevent any
1726 	   socket activity.
1727 	*/
1728 	mutex_lock(&connections_lock);
1729 	dlm_allow_conn = 0;
1730 	mutex_unlock(&connections_lock);
1731 	work_flush();
1732 	clean_writequeues();
1733 	foreach_conn(free_conn);
1734 	work_stop();
1735 
1736 	kmem_cache_destroy(con_cache);
1737 }
1738 
dlm_lowcomms_start(void)1739 int dlm_lowcomms_start(void)
1740 {
1741 	int error = -EINVAL;
1742 	struct connection *con;
1743 	int i;
1744 
1745 	for (i = 0; i < CONN_HASH_SIZE; i++)
1746 		INIT_HLIST_HEAD(&connection_hash[i]);
1747 
1748 	init_local();
1749 	if (!dlm_local_count) {
1750 		error = -ENOTCONN;
1751 		log_print("no local IP address has been set");
1752 		goto fail;
1753 	}
1754 
1755 	error = -ENOMEM;
1756 	con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
1757 				      __alignof__(struct connection), 0,
1758 				      NULL);
1759 	if (!con_cache)
1760 		goto fail;
1761 
1762 	error = work_start();
1763 	if (error)
1764 		goto fail_destroy;
1765 
1766 	dlm_allow_conn = 1;
1767 
1768 	/* Start listening */
1769 	if (dlm_config.ci_protocol == 0)
1770 		error = tcp_listen_for_all();
1771 	else
1772 		error = sctp_listen_for_all();
1773 	if (error)
1774 		goto fail_unlisten;
1775 
1776 	return 0;
1777 
1778 fail_unlisten:
1779 	dlm_allow_conn = 0;
1780 	con = nodeid2con(0,0);
1781 	if (con) {
1782 		close_connection(con, false, true, true);
1783 		kmem_cache_free(con_cache, con);
1784 	}
1785 fail_destroy:
1786 	kmem_cache_destroy(con_cache);
1787 fail:
1788 	return error;
1789 }
1790 
dlm_lowcomms_exit(void)1791 void dlm_lowcomms_exit(void)
1792 {
1793 	struct dlm_node_addr *na, *safe;
1794 
1795 	spin_lock(&dlm_node_addrs_spin);
1796 	list_for_each_entry_safe(na, safe, &dlm_node_addrs, list) {
1797 		list_del(&na->list);
1798 		while (na->addr_count--)
1799 			kfree(na->addr[na->addr_count]);
1800 		kfree(na);
1801 	}
1802 	spin_unlock(&dlm_node_addrs_spin);
1803 }
1804