xref: /openbmc/linux/net/ceph/messenger.c (revision 4f205687)
1 #include <linux/ceph/ceph_debug.h>
2 
3 #include <linux/crc32c.h>
4 #include <linux/ctype.h>
5 #include <linux/highmem.h>
6 #include <linux/inet.h>
7 #include <linux/kthread.h>
8 #include <linux/net.h>
9 #include <linux/nsproxy.h>
10 #include <linux/slab.h>
11 #include <linux/socket.h>
12 #include <linux/string.h>
13 #ifdef	CONFIG_BLOCK
14 #include <linux/bio.h>
15 #endif	/* CONFIG_BLOCK */
16 #include <linux/dns_resolver.h>
17 #include <net/tcp.h>
18 
19 #include <linux/ceph/ceph_features.h>
20 #include <linux/ceph/libceph.h>
21 #include <linux/ceph/messenger.h>
22 #include <linux/ceph/decode.h>
23 #include <linux/ceph/pagelist.h>
24 #include <linux/export.h>
25 
26 /*
27  * Ceph uses the messenger to exchange ceph_msg messages with other
28  * hosts in the system.  The messenger provides ordered and reliable
29  * delivery.  We tolerate TCP disconnects by reconnecting (with
30  * exponential backoff) in the case of a fault (disconnection, bad
31  * crc, protocol error).  Acks allow sent messages to be discarded by
32  * the sender.
33  */
34 
35 /*
36  * We track the state of the socket on a given connection using
37  * values defined below.  The transition to a new socket state is
38  * handled by a function which verifies we aren't coming from an
39  * unexpected state.
40  *
41  *      --------
42  *      | NEW* |  transient initial state
43  *      --------
44  *          | con_sock_state_init()
45  *          v
46  *      ----------
47  *      | CLOSED |  initialized, but no socket (and no
48  *      ----------  TCP connection)
49  *       ^      \
50  *       |       \ con_sock_state_connecting()
51  *       |        ----------------------
52  *       |                              \
53  *       + con_sock_state_closed()       \
54  *       |+---------------------------    \
55  *       | \                          \    \
56  *       |  -----------                \    \
57  *       |  | CLOSING |  socket event;  \    \
58  *       |  -----------  await close     \    \
59  *       |       ^                        \   |
60  *       |       |                         \  |
61  *       |       + con_sock_state_closing() \ |
62  *       |      / \                         | |
63  *       |     /   ---------------          | |
64  *       |    /                   \         v v
65  *       |   /                    --------------
66  *       |  /    -----------------| CONNECTING |  socket created, TCP
67  *       |  |   /                 --------------  connect initiated
68  *       |  |   | con_sock_state_connected()
69  *       |  |   v
70  *      -------------
71  *      | CONNECTED |  TCP connection established
72  *      -------------
73  *
74  * State values for ceph_connection->sock_state; NEW is assumed to be 0.
75  */
76 
77 #define CON_SOCK_STATE_NEW		0	/* -> CLOSED */
78 #define CON_SOCK_STATE_CLOSED		1	/* -> CONNECTING */
79 #define CON_SOCK_STATE_CONNECTING	2	/* -> CONNECTED or -> CLOSING */
80 #define CON_SOCK_STATE_CONNECTED	3	/* -> CLOSING or -> CLOSED */
81 #define CON_SOCK_STATE_CLOSING		4	/* -> CLOSED */
82 
83 /*
84  * connection states
85  */
86 #define CON_STATE_CLOSED        1  /* -> PREOPEN */
87 #define CON_STATE_PREOPEN       2  /* -> CONNECTING, CLOSED */
88 #define CON_STATE_CONNECTING    3  /* -> NEGOTIATING, CLOSED */
89 #define CON_STATE_NEGOTIATING   4  /* -> OPEN, CLOSED */
90 #define CON_STATE_OPEN          5  /* -> STANDBY, CLOSED */
91 #define CON_STATE_STANDBY       6  /* -> PREOPEN, CLOSED */
92 
93 /*
94  * ceph_connection flag bits
95  */
96 #define CON_FLAG_LOSSYTX           0  /* we can close channel or drop
97 				       * messages on errors */
98 #define CON_FLAG_KEEPALIVE_PENDING 1  /* we need to send a keepalive */
99 #define CON_FLAG_WRITE_PENDING	   2  /* we have data ready to send */
100 #define CON_FLAG_SOCK_CLOSED	   3  /* socket state changed to closed */
101 #define CON_FLAG_BACKOFF           4  /* need to retry queuing delayed work */
102 
103 static bool con_flag_valid(unsigned long con_flag)
104 {
105 	switch (con_flag) {
106 	case CON_FLAG_LOSSYTX:
107 	case CON_FLAG_KEEPALIVE_PENDING:
108 	case CON_FLAG_WRITE_PENDING:
109 	case CON_FLAG_SOCK_CLOSED:
110 	case CON_FLAG_BACKOFF:
111 		return true;
112 	default:
113 		return false;
114 	}
115 }
116 
117 static void con_flag_clear(struct ceph_connection *con, unsigned long con_flag)
118 {
119 	BUG_ON(!con_flag_valid(con_flag));
120 
121 	clear_bit(con_flag, &con->flags);
122 }
123 
124 static void con_flag_set(struct ceph_connection *con, unsigned long con_flag)
125 {
126 	BUG_ON(!con_flag_valid(con_flag));
127 
128 	set_bit(con_flag, &con->flags);
129 }
130 
131 static bool con_flag_test(struct ceph_connection *con, unsigned long con_flag)
132 {
133 	BUG_ON(!con_flag_valid(con_flag));
134 
135 	return test_bit(con_flag, &con->flags);
136 }
137 
138 static bool con_flag_test_and_clear(struct ceph_connection *con,
139 					unsigned long con_flag)
140 {
141 	BUG_ON(!con_flag_valid(con_flag));
142 
143 	return test_and_clear_bit(con_flag, &con->flags);
144 }
145 
146 static bool con_flag_test_and_set(struct ceph_connection *con,
147 					unsigned long con_flag)
148 {
149 	BUG_ON(!con_flag_valid(con_flag));
150 
151 	return test_and_set_bit(con_flag, &con->flags);
152 }
153 
154 /* Slab caches for frequently-allocated structures */
155 
156 static struct kmem_cache	*ceph_msg_cache;
157 static struct kmem_cache	*ceph_msg_data_cache;
158 
159 /* static tag bytes (protocol control messages) */
160 static char tag_msg = CEPH_MSGR_TAG_MSG;
161 static char tag_ack = CEPH_MSGR_TAG_ACK;
162 static char tag_keepalive = CEPH_MSGR_TAG_KEEPALIVE;
163 static char tag_keepalive2 = CEPH_MSGR_TAG_KEEPALIVE2;
164 
165 #ifdef CONFIG_LOCKDEP
166 static struct lock_class_key socket_class;
167 #endif
168 
169 /*
170  * When skipping (ignoring) a block of input we read it into a "skip
171  * buffer," which is this many bytes in size.
172  */
173 #define SKIP_BUF_SIZE	1024
174 
175 static void queue_con(struct ceph_connection *con);
176 static void cancel_con(struct ceph_connection *con);
177 static void ceph_con_workfn(struct work_struct *);
178 static void con_fault(struct ceph_connection *con);
179 
180 /*
181  * Nicely render a sockaddr as a string.  An array of formatted
182  * strings is used, to approximate reentrancy.
183  */
184 #define ADDR_STR_COUNT_LOG	5	/* log2(# address strings in array) */
185 #define ADDR_STR_COUNT		(1 << ADDR_STR_COUNT_LOG)
186 #define ADDR_STR_COUNT_MASK	(ADDR_STR_COUNT - 1)
187 #define MAX_ADDR_STR_LEN	64	/* 54 is enough */
188 
189 static char addr_str[ADDR_STR_COUNT][MAX_ADDR_STR_LEN];
190 static atomic_t addr_str_seq = ATOMIC_INIT(0);
191 
192 static struct page *zero_page;		/* used in certain error cases */
193 
194 const char *ceph_pr_addr(const struct sockaddr_storage *ss)
195 {
196 	int i;
197 	char *s;
198 	struct sockaddr_in *in4 = (struct sockaddr_in *) ss;
199 	struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) ss;
200 
201 	i = atomic_inc_return(&addr_str_seq) & ADDR_STR_COUNT_MASK;
202 	s = addr_str[i];
203 
204 	switch (ss->ss_family) {
205 	case AF_INET:
206 		snprintf(s, MAX_ADDR_STR_LEN, "%pI4:%hu", &in4->sin_addr,
207 			 ntohs(in4->sin_port));
208 		break;
209 
210 	case AF_INET6:
211 		snprintf(s, MAX_ADDR_STR_LEN, "[%pI6c]:%hu", &in6->sin6_addr,
212 			 ntohs(in6->sin6_port));
213 		break;
214 
215 	default:
216 		snprintf(s, MAX_ADDR_STR_LEN, "(unknown sockaddr family %hu)",
217 			 ss->ss_family);
218 	}
219 
220 	return s;
221 }
222 EXPORT_SYMBOL(ceph_pr_addr);
223 
224 static void encode_my_addr(struct ceph_messenger *msgr)
225 {
226 	memcpy(&msgr->my_enc_addr, &msgr->inst.addr, sizeof(msgr->my_enc_addr));
227 	ceph_encode_addr(&msgr->my_enc_addr);
228 }
229 
230 /*
231  * work queue for all reading and writing to/from the socket.
232  */
233 static struct workqueue_struct *ceph_msgr_wq;
234 
235 static int ceph_msgr_slab_init(void)
236 {
237 	BUG_ON(ceph_msg_cache);
238 	ceph_msg_cache = KMEM_CACHE(ceph_msg, 0);
239 	if (!ceph_msg_cache)
240 		return -ENOMEM;
241 
242 	BUG_ON(ceph_msg_data_cache);
243 	ceph_msg_data_cache = KMEM_CACHE(ceph_msg_data, 0);
244 	if (ceph_msg_data_cache)
245 		return 0;
246 
247 	kmem_cache_destroy(ceph_msg_cache);
248 	ceph_msg_cache = NULL;
249 
250 	return -ENOMEM;
251 }
252 
253 static void ceph_msgr_slab_exit(void)
254 {
255 	BUG_ON(!ceph_msg_data_cache);
256 	kmem_cache_destroy(ceph_msg_data_cache);
257 	ceph_msg_data_cache = NULL;
258 
259 	BUG_ON(!ceph_msg_cache);
260 	kmem_cache_destroy(ceph_msg_cache);
261 	ceph_msg_cache = NULL;
262 }
263 
264 static void _ceph_msgr_exit(void)
265 {
266 	if (ceph_msgr_wq) {
267 		destroy_workqueue(ceph_msgr_wq);
268 		ceph_msgr_wq = NULL;
269 	}
270 
271 	BUG_ON(zero_page == NULL);
272 	put_page(zero_page);
273 	zero_page = NULL;
274 
275 	ceph_msgr_slab_exit();
276 }
277 
278 int ceph_msgr_init(void)
279 {
280 	if (ceph_msgr_slab_init())
281 		return -ENOMEM;
282 
283 	BUG_ON(zero_page != NULL);
284 	zero_page = ZERO_PAGE(0);
285 	get_page(zero_page);
286 
287 	/*
288 	 * The number of active work items is limited by the number of
289 	 * connections, so leave @max_active at default.
290 	 */
291 	ceph_msgr_wq = alloc_workqueue("ceph-msgr", WQ_MEM_RECLAIM, 0);
292 	if (ceph_msgr_wq)
293 		return 0;
294 
295 	pr_err("msgr_init failed to create workqueue\n");
296 	_ceph_msgr_exit();
297 
298 	return -ENOMEM;
299 }
300 EXPORT_SYMBOL(ceph_msgr_init);
301 
302 void ceph_msgr_exit(void)
303 {
304 	BUG_ON(ceph_msgr_wq == NULL);
305 
306 	_ceph_msgr_exit();
307 }
308 EXPORT_SYMBOL(ceph_msgr_exit);
309 
310 void ceph_msgr_flush(void)
311 {
312 	flush_workqueue(ceph_msgr_wq);
313 }
314 EXPORT_SYMBOL(ceph_msgr_flush);
315 
316 /* Connection socket state transition functions */
317 
318 static void con_sock_state_init(struct ceph_connection *con)
319 {
320 	int old_state;
321 
322 	old_state = atomic_xchg(&con->sock_state, CON_SOCK_STATE_CLOSED);
323 	if (WARN_ON(old_state != CON_SOCK_STATE_NEW))
324 		printk("%s: unexpected old state %d\n", __func__, old_state);
325 	dout("%s con %p sock %d -> %d\n", __func__, con, old_state,
326 	     CON_SOCK_STATE_CLOSED);
327 }
328 
329 static void con_sock_state_connecting(struct ceph_connection *con)
330 {
331 	int old_state;
332 
333 	old_state = atomic_xchg(&con->sock_state, CON_SOCK_STATE_CONNECTING);
334 	if (WARN_ON(old_state != CON_SOCK_STATE_CLOSED))
335 		printk("%s: unexpected old state %d\n", __func__, old_state);
336 	dout("%s con %p sock %d -> %d\n", __func__, con, old_state,
337 	     CON_SOCK_STATE_CONNECTING);
338 }
339 
340 static void con_sock_state_connected(struct ceph_connection *con)
341 {
342 	int old_state;
343 
344 	old_state = atomic_xchg(&con->sock_state, CON_SOCK_STATE_CONNECTED);
345 	if (WARN_ON(old_state != CON_SOCK_STATE_CONNECTING))
346 		printk("%s: unexpected old state %d\n", __func__, old_state);
347 	dout("%s con %p sock %d -> %d\n", __func__, con, old_state,
348 	     CON_SOCK_STATE_CONNECTED);
349 }
350 
351 static void con_sock_state_closing(struct ceph_connection *con)
352 {
353 	int old_state;
354 
355 	old_state = atomic_xchg(&con->sock_state, CON_SOCK_STATE_CLOSING);
356 	if (WARN_ON(old_state != CON_SOCK_STATE_CONNECTING &&
357 			old_state != CON_SOCK_STATE_CONNECTED &&
358 			old_state != CON_SOCK_STATE_CLOSING))
359 		printk("%s: unexpected old state %d\n", __func__, old_state);
360 	dout("%s con %p sock %d -> %d\n", __func__, con, old_state,
361 	     CON_SOCK_STATE_CLOSING);
362 }
363 
364 static void con_sock_state_closed(struct ceph_connection *con)
365 {
366 	int old_state;
367 
368 	old_state = atomic_xchg(&con->sock_state, CON_SOCK_STATE_CLOSED);
369 	if (WARN_ON(old_state != CON_SOCK_STATE_CONNECTED &&
370 		    old_state != CON_SOCK_STATE_CLOSING &&
371 		    old_state != CON_SOCK_STATE_CONNECTING &&
372 		    old_state != CON_SOCK_STATE_CLOSED))
373 		printk("%s: unexpected old state %d\n", __func__, old_state);
374 	dout("%s con %p sock %d -> %d\n", __func__, con, old_state,
375 	     CON_SOCK_STATE_CLOSED);
376 }
377 
378 /*
379  * socket callback functions
380  */
381 
382 /* data available on socket, or listen socket received a connect */
383 static void ceph_sock_data_ready(struct sock *sk)
384 {
385 	struct ceph_connection *con = sk->sk_user_data;
386 	if (atomic_read(&con->msgr->stopping)) {
387 		return;
388 	}
389 
390 	if (sk->sk_state != TCP_CLOSE_WAIT) {
391 		dout("%s on %p state = %lu, queueing work\n", __func__,
392 		     con, con->state);
393 		queue_con(con);
394 	}
395 }
396 
397 /* socket has buffer space for writing */
398 static void ceph_sock_write_space(struct sock *sk)
399 {
400 	struct ceph_connection *con = sk->sk_user_data;
401 
402 	/* only queue to workqueue if there is data we want to write,
403 	 * and there is sufficient space in the socket buffer to accept
404 	 * more data.  clear SOCK_NOSPACE so that ceph_sock_write_space()
405 	 * doesn't get called again until try_write() fills the socket
406 	 * buffer. See net/ipv4/tcp_input.c:tcp_check_space()
407 	 * and net/core/stream.c:sk_stream_write_space().
408 	 */
409 	if (con_flag_test(con, CON_FLAG_WRITE_PENDING)) {
410 		if (sk_stream_is_writeable(sk)) {
411 			dout("%s %p queueing write work\n", __func__, con);
412 			clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
413 			queue_con(con);
414 		}
415 	} else {
416 		dout("%s %p nothing to write\n", __func__, con);
417 	}
418 }
419 
420 /* socket's state has changed */
421 static void ceph_sock_state_change(struct sock *sk)
422 {
423 	struct ceph_connection *con = sk->sk_user_data;
424 
425 	dout("%s %p state = %lu sk_state = %u\n", __func__,
426 	     con, con->state, sk->sk_state);
427 
428 	switch (sk->sk_state) {
429 	case TCP_CLOSE:
430 		dout("%s TCP_CLOSE\n", __func__);
431 	case TCP_CLOSE_WAIT:
432 		dout("%s TCP_CLOSE_WAIT\n", __func__);
433 		con_sock_state_closing(con);
434 		con_flag_set(con, CON_FLAG_SOCK_CLOSED);
435 		queue_con(con);
436 		break;
437 	case TCP_ESTABLISHED:
438 		dout("%s TCP_ESTABLISHED\n", __func__);
439 		con_sock_state_connected(con);
440 		queue_con(con);
441 		break;
442 	default:	/* Everything else is uninteresting */
443 		break;
444 	}
445 }
446 
447 /*
448  * set up socket callbacks
449  */
450 static void set_sock_callbacks(struct socket *sock,
451 			       struct ceph_connection *con)
452 {
453 	struct sock *sk = sock->sk;
454 	sk->sk_user_data = con;
455 	sk->sk_data_ready = ceph_sock_data_ready;
456 	sk->sk_write_space = ceph_sock_write_space;
457 	sk->sk_state_change = ceph_sock_state_change;
458 }
459 
460 
461 /*
462  * socket helpers
463  */
464 
465 /*
466  * initiate connection to a remote socket.
467  */
468 static int ceph_tcp_connect(struct ceph_connection *con)
469 {
470 	struct sockaddr_storage *paddr = &con->peer_addr.in_addr;
471 	struct socket *sock;
472 	int ret;
473 
474 	BUG_ON(con->sock);
475 	ret = sock_create_kern(read_pnet(&con->msgr->net), paddr->ss_family,
476 			       SOCK_STREAM, IPPROTO_TCP, &sock);
477 	if (ret)
478 		return ret;
479 	sock->sk->sk_allocation = GFP_NOFS;
480 
481 #ifdef CONFIG_LOCKDEP
482 	lockdep_set_class(&sock->sk->sk_lock, &socket_class);
483 #endif
484 
485 	set_sock_callbacks(sock, con);
486 
487 	dout("connect %s\n", ceph_pr_addr(&con->peer_addr.in_addr));
488 
489 	con_sock_state_connecting(con);
490 	ret = sock->ops->connect(sock, (struct sockaddr *)paddr, sizeof(*paddr),
491 				 O_NONBLOCK);
492 	if (ret == -EINPROGRESS) {
493 		dout("connect %s EINPROGRESS sk_state = %u\n",
494 		     ceph_pr_addr(&con->peer_addr.in_addr),
495 		     sock->sk->sk_state);
496 	} else if (ret < 0) {
497 		pr_err("connect %s error %d\n",
498 		       ceph_pr_addr(&con->peer_addr.in_addr), ret);
499 		sock_release(sock);
500 		return ret;
501 	}
502 
503 	if (ceph_test_opt(from_msgr(con->msgr), TCP_NODELAY)) {
504 		int optval = 1;
505 
506 		ret = kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY,
507 					(char *)&optval, sizeof(optval));
508 		if (ret)
509 			pr_err("kernel_setsockopt(TCP_NODELAY) failed: %d",
510 			       ret);
511 	}
512 
513 	con->sock = sock;
514 	return 0;
515 }
516 
517 static int ceph_tcp_recvmsg(struct socket *sock, void *buf, size_t len)
518 {
519 	struct kvec iov = {buf, len};
520 	struct msghdr msg = { .msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL };
521 	int r;
522 
523 	r = kernel_recvmsg(sock, &msg, &iov, 1, len, msg.msg_flags);
524 	if (r == -EAGAIN)
525 		r = 0;
526 	return r;
527 }
528 
529 static int ceph_tcp_recvpage(struct socket *sock, struct page *page,
530 		     int page_offset, size_t length)
531 {
532 	void *kaddr;
533 	int ret;
534 
535 	BUG_ON(page_offset + length > PAGE_SIZE);
536 
537 	kaddr = kmap(page);
538 	BUG_ON(!kaddr);
539 	ret = ceph_tcp_recvmsg(sock, kaddr + page_offset, length);
540 	kunmap(page);
541 
542 	return ret;
543 }
544 
545 /*
546  * write something.  @more is true if caller will be sending more data
547  * shortly.
548  */
549 static int ceph_tcp_sendmsg(struct socket *sock, struct kvec *iov,
550 		     size_t kvlen, size_t len, int more)
551 {
552 	struct msghdr msg = { .msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL };
553 	int r;
554 
555 	if (more)
556 		msg.msg_flags |= MSG_MORE;
557 	else
558 		msg.msg_flags |= MSG_EOR;  /* superfluous, but what the hell */
559 
560 	r = kernel_sendmsg(sock, &msg, iov, kvlen, len);
561 	if (r == -EAGAIN)
562 		r = 0;
563 	return r;
564 }
565 
566 static int __ceph_tcp_sendpage(struct socket *sock, struct page *page,
567 		     int offset, size_t size, bool more)
568 {
569 	int flags = MSG_DONTWAIT | MSG_NOSIGNAL | (more ? MSG_MORE : MSG_EOR);
570 	int ret;
571 
572 	ret = kernel_sendpage(sock, page, offset, size, flags);
573 	if (ret == -EAGAIN)
574 		ret = 0;
575 
576 	return ret;
577 }
578 
579 static int ceph_tcp_sendpage(struct socket *sock, struct page *page,
580 		     int offset, size_t size, bool more)
581 {
582 	int ret;
583 	struct kvec iov;
584 
585 	/* sendpage cannot properly handle pages with page_count == 0,
586 	 * we need to fallback to sendmsg if that's the case */
587 	if (page_count(page) >= 1)
588 		return __ceph_tcp_sendpage(sock, page, offset, size, more);
589 
590 	iov.iov_base = kmap(page) + offset;
591 	iov.iov_len = size;
592 	ret = ceph_tcp_sendmsg(sock, &iov, 1, size, more);
593 	kunmap(page);
594 
595 	return ret;
596 }
597 
598 /*
599  * Shutdown/close the socket for the given connection.
600  */
601 static int con_close_socket(struct ceph_connection *con)
602 {
603 	int rc = 0;
604 
605 	dout("con_close_socket on %p sock %p\n", con, con->sock);
606 	if (con->sock) {
607 		rc = con->sock->ops->shutdown(con->sock, SHUT_RDWR);
608 		sock_release(con->sock);
609 		con->sock = NULL;
610 	}
611 
612 	/*
613 	 * Forcibly clear the SOCK_CLOSED flag.  It gets set
614 	 * independent of the connection mutex, and we could have
615 	 * received a socket close event before we had the chance to
616 	 * shut the socket down.
617 	 */
618 	con_flag_clear(con, CON_FLAG_SOCK_CLOSED);
619 
620 	con_sock_state_closed(con);
621 	return rc;
622 }
623 
624 /*
625  * Reset a connection.  Discard all incoming and outgoing messages
626  * and clear *_seq state.
627  */
628 static void ceph_msg_remove(struct ceph_msg *msg)
629 {
630 	list_del_init(&msg->list_head);
631 
632 	ceph_msg_put(msg);
633 }
634 static void ceph_msg_remove_list(struct list_head *head)
635 {
636 	while (!list_empty(head)) {
637 		struct ceph_msg *msg = list_first_entry(head, struct ceph_msg,
638 							list_head);
639 		ceph_msg_remove(msg);
640 	}
641 }
642 
643 static void reset_connection(struct ceph_connection *con)
644 {
645 	/* reset connection, out_queue, msg_ and connect_seq */
646 	/* discard existing out_queue and msg_seq */
647 	dout("reset_connection %p\n", con);
648 	ceph_msg_remove_list(&con->out_queue);
649 	ceph_msg_remove_list(&con->out_sent);
650 
651 	if (con->in_msg) {
652 		BUG_ON(con->in_msg->con != con);
653 		ceph_msg_put(con->in_msg);
654 		con->in_msg = NULL;
655 	}
656 
657 	con->connect_seq = 0;
658 	con->out_seq = 0;
659 	if (con->out_msg) {
660 		BUG_ON(con->out_msg->con != con);
661 		ceph_msg_put(con->out_msg);
662 		con->out_msg = NULL;
663 	}
664 	con->in_seq = 0;
665 	con->in_seq_acked = 0;
666 
667 	con->out_skip = 0;
668 }
669 
670 /*
671  * mark a peer down.  drop any open connections.
672  */
673 void ceph_con_close(struct ceph_connection *con)
674 {
675 	mutex_lock(&con->mutex);
676 	dout("con_close %p peer %s\n", con,
677 	     ceph_pr_addr(&con->peer_addr.in_addr));
678 	con->state = CON_STATE_CLOSED;
679 
680 	con_flag_clear(con, CON_FLAG_LOSSYTX);	/* so we retry next connect */
681 	con_flag_clear(con, CON_FLAG_KEEPALIVE_PENDING);
682 	con_flag_clear(con, CON_FLAG_WRITE_PENDING);
683 	con_flag_clear(con, CON_FLAG_BACKOFF);
684 
685 	reset_connection(con);
686 	con->peer_global_seq = 0;
687 	cancel_con(con);
688 	con_close_socket(con);
689 	mutex_unlock(&con->mutex);
690 }
691 EXPORT_SYMBOL(ceph_con_close);
692 
693 /*
694  * Reopen a closed connection, with a new peer address.
695  */
696 void ceph_con_open(struct ceph_connection *con,
697 		   __u8 entity_type, __u64 entity_num,
698 		   struct ceph_entity_addr *addr)
699 {
700 	mutex_lock(&con->mutex);
701 	dout("con_open %p %s\n", con, ceph_pr_addr(&addr->in_addr));
702 
703 	WARN_ON(con->state != CON_STATE_CLOSED);
704 	con->state = CON_STATE_PREOPEN;
705 
706 	con->peer_name.type = (__u8) entity_type;
707 	con->peer_name.num = cpu_to_le64(entity_num);
708 
709 	memcpy(&con->peer_addr, addr, sizeof(*addr));
710 	con->delay = 0;      /* reset backoff memory */
711 	mutex_unlock(&con->mutex);
712 	queue_con(con);
713 }
714 EXPORT_SYMBOL(ceph_con_open);
715 
716 /*
717  * return true if this connection ever successfully opened
718  */
719 bool ceph_con_opened(struct ceph_connection *con)
720 {
721 	return con->connect_seq > 0;
722 }
723 
724 /*
725  * initialize a new connection.
726  */
727 void ceph_con_init(struct ceph_connection *con, void *private,
728 	const struct ceph_connection_operations *ops,
729 	struct ceph_messenger *msgr)
730 {
731 	dout("con_init %p\n", con);
732 	memset(con, 0, sizeof(*con));
733 	con->private = private;
734 	con->ops = ops;
735 	con->msgr = msgr;
736 
737 	con_sock_state_init(con);
738 
739 	mutex_init(&con->mutex);
740 	INIT_LIST_HEAD(&con->out_queue);
741 	INIT_LIST_HEAD(&con->out_sent);
742 	INIT_DELAYED_WORK(&con->work, ceph_con_workfn);
743 
744 	con->state = CON_STATE_CLOSED;
745 }
746 EXPORT_SYMBOL(ceph_con_init);
747 
748 
749 /*
750  * We maintain a global counter to order connection attempts.  Get
751  * a unique seq greater than @gt.
752  */
753 static u32 get_global_seq(struct ceph_messenger *msgr, u32 gt)
754 {
755 	u32 ret;
756 
757 	spin_lock(&msgr->global_seq_lock);
758 	if (msgr->global_seq < gt)
759 		msgr->global_seq = gt;
760 	ret = ++msgr->global_seq;
761 	spin_unlock(&msgr->global_seq_lock);
762 	return ret;
763 }
764 
765 static void con_out_kvec_reset(struct ceph_connection *con)
766 {
767 	BUG_ON(con->out_skip);
768 
769 	con->out_kvec_left = 0;
770 	con->out_kvec_bytes = 0;
771 	con->out_kvec_cur = &con->out_kvec[0];
772 }
773 
774 static void con_out_kvec_add(struct ceph_connection *con,
775 				size_t size, void *data)
776 {
777 	int index = con->out_kvec_left;
778 
779 	BUG_ON(con->out_skip);
780 	BUG_ON(index >= ARRAY_SIZE(con->out_kvec));
781 
782 	con->out_kvec[index].iov_len = size;
783 	con->out_kvec[index].iov_base = data;
784 	con->out_kvec_left++;
785 	con->out_kvec_bytes += size;
786 }
787 
788 /*
789  * Chop off a kvec from the end.  Return residual number of bytes for
790  * that kvec, i.e. how many bytes would have been written if the kvec
791  * hadn't been nuked.
792  */
793 static int con_out_kvec_skip(struct ceph_connection *con)
794 {
795 	int off = con->out_kvec_cur - con->out_kvec;
796 	int skip = 0;
797 
798 	if (con->out_kvec_bytes > 0) {
799 		skip = con->out_kvec[off + con->out_kvec_left - 1].iov_len;
800 		BUG_ON(con->out_kvec_bytes < skip);
801 		BUG_ON(!con->out_kvec_left);
802 		con->out_kvec_bytes -= skip;
803 		con->out_kvec_left--;
804 	}
805 
806 	return skip;
807 }
808 
809 #ifdef CONFIG_BLOCK
810 
811 /*
812  * For a bio data item, a piece is whatever remains of the next
813  * entry in the current bio iovec, or the first entry in the next
814  * bio in the list.
815  */
816 static void ceph_msg_data_bio_cursor_init(struct ceph_msg_data_cursor *cursor,
817 					size_t length)
818 {
819 	struct ceph_msg_data *data = cursor->data;
820 	struct bio *bio;
821 
822 	BUG_ON(data->type != CEPH_MSG_DATA_BIO);
823 
824 	bio = data->bio;
825 	BUG_ON(!bio);
826 
827 	cursor->resid = min(length, data->bio_length);
828 	cursor->bio = bio;
829 	cursor->bvec_iter = bio->bi_iter;
830 	cursor->last_piece =
831 		cursor->resid <= bio_iter_len(bio, cursor->bvec_iter);
832 }
833 
834 static struct page *ceph_msg_data_bio_next(struct ceph_msg_data_cursor *cursor,
835 						size_t *page_offset,
836 						size_t *length)
837 {
838 	struct ceph_msg_data *data = cursor->data;
839 	struct bio *bio;
840 	struct bio_vec bio_vec;
841 
842 	BUG_ON(data->type != CEPH_MSG_DATA_BIO);
843 
844 	bio = cursor->bio;
845 	BUG_ON(!bio);
846 
847 	bio_vec = bio_iter_iovec(bio, cursor->bvec_iter);
848 
849 	*page_offset = (size_t) bio_vec.bv_offset;
850 	BUG_ON(*page_offset >= PAGE_SIZE);
851 	if (cursor->last_piece) /* pagelist offset is always 0 */
852 		*length = cursor->resid;
853 	else
854 		*length = (size_t) bio_vec.bv_len;
855 	BUG_ON(*length > cursor->resid);
856 	BUG_ON(*page_offset + *length > PAGE_SIZE);
857 
858 	return bio_vec.bv_page;
859 }
860 
861 static bool ceph_msg_data_bio_advance(struct ceph_msg_data_cursor *cursor,
862 					size_t bytes)
863 {
864 	struct bio *bio;
865 	struct bio_vec bio_vec;
866 
867 	BUG_ON(cursor->data->type != CEPH_MSG_DATA_BIO);
868 
869 	bio = cursor->bio;
870 	BUG_ON(!bio);
871 
872 	bio_vec = bio_iter_iovec(bio, cursor->bvec_iter);
873 
874 	/* Advance the cursor offset */
875 
876 	BUG_ON(cursor->resid < bytes);
877 	cursor->resid -= bytes;
878 
879 	bio_advance_iter(bio, &cursor->bvec_iter, bytes);
880 
881 	if (bytes < bio_vec.bv_len)
882 		return false;	/* more bytes to process in this segment */
883 
884 	/* Move on to the next segment, and possibly the next bio */
885 
886 	if (!cursor->bvec_iter.bi_size) {
887 		bio = bio->bi_next;
888 		cursor->bio = bio;
889 		if (bio)
890 			cursor->bvec_iter = bio->bi_iter;
891 		else
892 			memset(&cursor->bvec_iter, 0,
893 			       sizeof(cursor->bvec_iter));
894 	}
895 
896 	if (!cursor->last_piece) {
897 		BUG_ON(!cursor->resid);
898 		BUG_ON(!bio);
899 		/* A short read is OK, so use <= rather than == */
900 		if (cursor->resid <= bio_iter_len(bio, cursor->bvec_iter))
901 			cursor->last_piece = true;
902 	}
903 
904 	return true;
905 }
906 #endif /* CONFIG_BLOCK */
907 
908 /*
909  * For a page array, a piece comes from the first page in the array
910  * that has not already been fully consumed.
911  */
912 static void ceph_msg_data_pages_cursor_init(struct ceph_msg_data_cursor *cursor,
913 					size_t length)
914 {
915 	struct ceph_msg_data *data = cursor->data;
916 	int page_count;
917 
918 	BUG_ON(data->type != CEPH_MSG_DATA_PAGES);
919 
920 	BUG_ON(!data->pages);
921 	BUG_ON(!data->length);
922 
923 	cursor->resid = min(length, data->length);
924 	page_count = calc_pages_for(data->alignment, (u64)data->length);
925 	cursor->page_offset = data->alignment & ~PAGE_MASK;
926 	cursor->page_index = 0;
927 	BUG_ON(page_count > (int)USHRT_MAX);
928 	cursor->page_count = (unsigned short)page_count;
929 	BUG_ON(length > SIZE_MAX - cursor->page_offset);
930 	cursor->last_piece = cursor->page_offset + cursor->resid <= PAGE_SIZE;
931 }
932 
933 static struct page *
934 ceph_msg_data_pages_next(struct ceph_msg_data_cursor *cursor,
935 					size_t *page_offset, size_t *length)
936 {
937 	struct ceph_msg_data *data = cursor->data;
938 
939 	BUG_ON(data->type != CEPH_MSG_DATA_PAGES);
940 
941 	BUG_ON(cursor->page_index >= cursor->page_count);
942 	BUG_ON(cursor->page_offset >= PAGE_SIZE);
943 
944 	*page_offset = cursor->page_offset;
945 	if (cursor->last_piece)
946 		*length = cursor->resid;
947 	else
948 		*length = PAGE_SIZE - *page_offset;
949 
950 	return data->pages[cursor->page_index];
951 }
952 
953 static bool ceph_msg_data_pages_advance(struct ceph_msg_data_cursor *cursor,
954 						size_t bytes)
955 {
956 	BUG_ON(cursor->data->type != CEPH_MSG_DATA_PAGES);
957 
958 	BUG_ON(cursor->page_offset + bytes > PAGE_SIZE);
959 
960 	/* Advance the cursor page offset */
961 
962 	cursor->resid -= bytes;
963 	cursor->page_offset = (cursor->page_offset + bytes) & ~PAGE_MASK;
964 	if (!bytes || cursor->page_offset)
965 		return false;	/* more bytes to process in the current page */
966 
967 	if (!cursor->resid)
968 		return false;   /* no more data */
969 
970 	/* Move on to the next page; offset is already at 0 */
971 
972 	BUG_ON(cursor->page_index >= cursor->page_count);
973 	cursor->page_index++;
974 	cursor->last_piece = cursor->resid <= PAGE_SIZE;
975 
976 	return true;
977 }
978 
979 /*
980  * For a pagelist, a piece is whatever remains to be consumed in the
981  * first page in the list, or the front of the next page.
982  */
983 static void
984 ceph_msg_data_pagelist_cursor_init(struct ceph_msg_data_cursor *cursor,
985 					size_t length)
986 {
987 	struct ceph_msg_data *data = cursor->data;
988 	struct ceph_pagelist *pagelist;
989 	struct page *page;
990 
991 	BUG_ON(data->type != CEPH_MSG_DATA_PAGELIST);
992 
993 	pagelist = data->pagelist;
994 	BUG_ON(!pagelist);
995 
996 	if (!length)
997 		return;		/* pagelist can be assigned but empty */
998 
999 	BUG_ON(list_empty(&pagelist->head));
1000 	page = list_first_entry(&pagelist->head, struct page, lru);
1001 
1002 	cursor->resid = min(length, pagelist->length);
1003 	cursor->page = page;
1004 	cursor->offset = 0;
1005 	cursor->last_piece = cursor->resid <= PAGE_SIZE;
1006 }
1007 
1008 static struct page *
1009 ceph_msg_data_pagelist_next(struct ceph_msg_data_cursor *cursor,
1010 				size_t *page_offset, size_t *length)
1011 {
1012 	struct ceph_msg_data *data = cursor->data;
1013 	struct ceph_pagelist *pagelist;
1014 
1015 	BUG_ON(data->type != CEPH_MSG_DATA_PAGELIST);
1016 
1017 	pagelist = data->pagelist;
1018 	BUG_ON(!pagelist);
1019 
1020 	BUG_ON(!cursor->page);
1021 	BUG_ON(cursor->offset + cursor->resid != pagelist->length);
1022 
1023 	/* offset of first page in pagelist is always 0 */
1024 	*page_offset = cursor->offset & ~PAGE_MASK;
1025 	if (cursor->last_piece)
1026 		*length = cursor->resid;
1027 	else
1028 		*length = PAGE_SIZE - *page_offset;
1029 
1030 	return cursor->page;
1031 }
1032 
1033 static bool ceph_msg_data_pagelist_advance(struct ceph_msg_data_cursor *cursor,
1034 						size_t bytes)
1035 {
1036 	struct ceph_msg_data *data = cursor->data;
1037 	struct ceph_pagelist *pagelist;
1038 
1039 	BUG_ON(data->type != CEPH_MSG_DATA_PAGELIST);
1040 
1041 	pagelist = data->pagelist;
1042 	BUG_ON(!pagelist);
1043 
1044 	BUG_ON(cursor->offset + cursor->resid != pagelist->length);
1045 	BUG_ON((cursor->offset & ~PAGE_MASK) + bytes > PAGE_SIZE);
1046 
1047 	/* Advance the cursor offset */
1048 
1049 	cursor->resid -= bytes;
1050 	cursor->offset += bytes;
1051 	/* offset of first page in pagelist is always 0 */
1052 	if (!bytes || cursor->offset & ~PAGE_MASK)
1053 		return false;	/* more bytes to process in the current page */
1054 
1055 	if (!cursor->resid)
1056 		return false;   /* no more data */
1057 
1058 	/* Move on to the next page */
1059 
1060 	BUG_ON(list_is_last(&cursor->page->lru, &pagelist->head));
1061 	cursor->page = list_next_entry(cursor->page, lru);
1062 	cursor->last_piece = cursor->resid <= PAGE_SIZE;
1063 
1064 	return true;
1065 }
1066 
1067 /*
1068  * Message data is handled (sent or received) in pieces, where each
1069  * piece resides on a single page.  The network layer might not
1070  * consume an entire piece at once.  A data item's cursor keeps
1071  * track of which piece is next to process and how much remains to
1072  * be processed in that piece.  It also tracks whether the current
1073  * piece is the last one in the data item.
1074  */
1075 static void __ceph_msg_data_cursor_init(struct ceph_msg_data_cursor *cursor)
1076 {
1077 	size_t length = cursor->total_resid;
1078 
1079 	switch (cursor->data->type) {
1080 	case CEPH_MSG_DATA_PAGELIST:
1081 		ceph_msg_data_pagelist_cursor_init(cursor, length);
1082 		break;
1083 	case CEPH_MSG_DATA_PAGES:
1084 		ceph_msg_data_pages_cursor_init(cursor, length);
1085 		break;
1086 #ifdef CONFIG_BLOCK
1087 	case CEPH_MSG_DATA_BIO:
1088 		ceph_msg_data_bio_cursor_init(cursor, length);
1089 		break;
1090 #endif /* CONFIG_BLOCK */
1091 	case CEPH_MSG_DATA_NONE:
1092 	default:
1093 		/* BUG(); */
1094 		break;
1095 	}
1096 	cursor->need_crc = true;
1097 }
1098 
1099 static void ceph_msg_data_cursor_init(struct ceph_msg *msg, size_t length)
1100 {
1101 	struct ceph_msg_data_cursor *cursor = &msg->cursor;
1102 	struct ceph_msg_data *data;
1103 
1104 	BUG_ON(!length);
1105 	BUG_ON(length > msg->data_length);
1106 	BUG_ON(list_empty(&msg->data));
1107 
1108 	cursor->data_head = &msg->data;
1109 	cursor->total_resid = length;
1110 	data = list_first_entry(&msg->data, struct ceph_msg_data, links);
1111 	cursor->data = data;
1112 
1113 	__ceph_msg_data_cursor_init(cursor);
1114 }
1115 
1116 /*
1117  * Return the page containing the next piece to process for a given
1118  * data item, and supply the page offset and length of that piece.
1119  * Indicate whether this is the last piece in this data item.
1120  */
1121 static struct page *ceph_msg_data_next(struct ceph_msg_data_cursor *cursor,
1122 					size_t *page_offset, size_t *length,
1123 					bool *last_piece)
1124 {
1125 	struct page *page;
1126 
1127 	switch (cursor->data->type) {
1128 	case CEPH_MSG_DATA_PAGELIST:
1129 		page = ceph_msg_data_pagelist_next(cursor, page_offset, length);
1130 		break;
1131 	case CEPH_MSG_DATA_PAGES:
1132 		page = ceph_msg_data_pages_next(cursor, page_offset, length);
1133 		break;
1134 #ifdef CONFIG_BLOCK
1135 	case CEPH_MSG_DATA_BIO:
1136 		page = ceph_msg_data_bio_next(cursor, page_offset, length);
1137 		break;
1138 #endif /* CONFIG_BLOCK */
1139 	case CEPH_MSG_DATA_NONE:
1140 	default:
1141 		page = NULL;
1142 		break;
1143 	}
1144 	BUG_ON(!page);
1145 	BUG_ON(*page_offset + *length > PAGE_SIZE);
1146 	BUG_ON(!*length);
1147 	if (last_piece)
1148 		*last_piece = cursor->last_piece;
1149 
1150 	return page;
1151 }
1152 
1153 /*
1154  * Returns true if the result moves the cursor on to the next piece
1155  * of the data item.
1156  */
1157 static bool ceph_msg_data_advance(struct ceph_msg_data_cursor *cursor,
1158 				size_t bytes)
1159 {
1160 	bool new_piece;
1161 
1162 	BUG_ON(bytes > cursor->resid);
1163 	switch (cursor->data->type) {
1164 	case CEPH_MSG_DATA_PAGELIST:
1165 		new_piece = ceph_msg_data_pagelist_advance(cursor, bytes);
1166 		break;
1167 	case CEPH_MSG_DATA_PAGES:
1168 		new_piece = ceph_msg_data_pages_advance(cursor, bytes);
1169 		break;
1170 #ifdef CONFIG_BLOCK
1171 	case CEPH_MSG_DATA_BIO:
1172 		new_piece = ceph_msg_data_bio_advance(cursor, bytes);
1173 		break;
1174 #endif /* CONFIG_BLOCK */
1175 	case CEPH_MSG_DATA_NONE:
1176 	default:
1177 		BUG();
1178 		break;
1179 	}
1180 	cursor->total_resid -= bytes;
1181 
1182 	if (!cursor->resid && cursor->total_resid) {
1183 		WARN_ON(!cursor->last_piece);
1184 		BUG_ON(list_is_last(&cursor->data->links, cursor->data_head));
1185 		cursor->data = list_next_entry(cursor->data, links);
1186 		__ceph_msg_data_cursor_init(cursor);
1187 		new_piece = true;
1188 	}
1189 	cursor->need_crc = new_piece;
1190 
1191 	return new_piece;
1192 }
1193 
1194 static size_t sizeof_footer(struct ceph_connection *con)
1195 {
1196 	return (con->peer_features & CEPH_FEATURE_MSG_AUTH) ?
1197 	    sizeof(struct ceph_msg_footer) :
1198 	    sizeof(struct ceph_msg_footer_old);
1199 }
1200 
1201 static void prepare_message_data(struct ceph_msg *msg, u32 data_len)
1202 {
1203 	BUG_ON(!msg);
1204 	BUG_ON(!data_len);
1205 
1206 	/* Initialize data cursor */
1207 
1208 	ceph_msg_data_cursor_init(msg, (size_t)data_len);
1209 }
1210 
1211 /*
1212  * Prepare footer for currently outgoing message, and finish things
1213  * off.  Assumes out_kvec* are already valid.. we just add on to the end.
1214  */
1215 static void prepare_write_message_footer(struct ceph_connection *con)
1216 {
1217 	struct ceph_msg *m = con->out_msg;
1218 
1219 	m->footer.flags |= CEPH_MSG_FOOTER_COMPLETE;
1220 
1221 	dout("prepare_write_message_footer %p\n", con);
1222 	con_out_kvec_add(con, sizeof_footer(con), &m->footer);
1223 	if (con->peer_features & CEPH_FEATURE_MSG_AUTH) {
1224 		if (con->ops->sign_message)
1225 			con->ops->sign_message(m);
1226 		else
1227 			m->footer.sig = 0;
1228 	} else {
1229 		m->old_footer.flags = m->footer.flags;
1230 	}
1231 	con->out_more = m->more_to_follow;
1232 	con->out_msg_done = true;
1233 }
1234 
1235 /*
1236  * Prepare headers for the next outgoing message.
1237  */
1238 static void prepare_write_message(struct ceph_connection *con)
1239 {
1240 	struct ceph_msg *m;
1241 	u32 crc;
1242 
1243 	con_out_kvec_reset(con);
1244 	con->out_msg_done = false;
1245 
1246 	/* Sneak an ack in there first?  If we can get it into the same
1247 	 * TCP packet that's a good thing. */
1248 	if (con->in_seq > con->in_seq_acked) {
1249 		con->in_seq_acked = con->in_seq;
1250 		con_out_kvec_add(con, sizeof (tag_ack), &tag_ack);
1251 		con->out_temp_ack = cpu_to_le64(con->in_seq_acked);
1252 		con_out_kvec_add(con, sizeof (con->out_temp_ack),
1253 			&con->out_temp_ack);
1254 	}
1255 
1256 	BUG_ON(list_empty(&con->out_queue));
1257 	m = list_first_entry(&con->out_queue, struct ceph_msg, list_head);
1258 	con->out_msg = m;
1259 	BUG_ON(m->con != con);
1260 
1261 	/* put message on sent list */
1262 	ceph_msg_get(m);
1263 	list_move_tail(&m->list_head, &con->out_sent);
1264 
1265 	/*
1266 	 * only assign outgoing seq # if we haven't sent this message
1267 	 * yet.  if it is requeued, resend with it's original seq.
1268 	 */
1269 	if (m->needs_out_seq) {
1270 		m->hdr.seq = cpu_to_le64(++con->out_seq);
1271 		m->needs_out_seq = false;
1272 	}
1273 	WARN_ON(m->data_length != le32_to_cpu(m->hdr.data_len));
1274 
1275 	dout("prepare_write_message %p seq %lld type %d len %d+%d+%zd\n",
1276 	     m, con->out_seq, le16_to_cpu(m->hdr.type),
1277 	     le32_to_cpu(m->hdr.front_len), le32_to_cpu(m->hdr.middle_len),
1278 	     m->data_length);
1279 	BUG_ON(le32_to_cpu(m->hdr.front_len) != m->front.iov_len);
1280 
1281 	/* tag + hdr + front + middle */
1282 	con_out_kvec_add(con, sizeof (tag_msg), &tag_msg);
1283 	con_out_kvec_add(con, sizeof(con->out_hdr), &con->out_hdr);
1284 	con_out_kvec_add(con, m->front.iov_len, m->front.iov_base);
1285 
1286 	if (m->middle)
1287 		con_out_kvec_add(con, m->middle->vec.iov_len,
1288 			m->middle->vec.iov_base);
1289 
1290 	/* fill in hdr crc and finalize hdr */
1291 	crc = crc32c(0, &m->hdr, offsetof(struct ceph_msg_header, crc));
1292 	con->out_msg->hdr.crc = cpu_to_le32(crc);
1293 	memcpy(&con->out_hdr, &con->out_msg->hdr, sizeof(con->out_hdr));
1294 
1295 	/* fill in front and middle crc, footer */
1296 	crc = crc32c(0, m->front.iov_base, m->front.iov_len);
1297 	con->out_msg->footer.front_crc = cpu_to_le32(crc);
1298 	if (m->middle) {
1299 		crc = crc32c(0, m->middle->vec.iov_base,
1300 				m->middle->vec.iov_len);
1301 		con->out_msg->footer.middle_crc = cpu_to_le32(crc);
1302 	} else
1303 		con->out_msg->footer.middle_crc = 0;
1304 	dout("%s front_crc %u middle_crc %u\n", __func__,
1305 	     le32_to_cpu(con->out_msg->footer.front_crc),
1306 	     le32_to_cpu(con->out_msg->footer.middle_crc));
1307 	con->out_msg->footer.flags = 0;
1308 
1309 	/* is there a data payload? */
1310 	con->out_msg->footer.data_crc = 0;
1311 	if (m->data_length) {
1312 		prepare_message_data(con->out_msg, m->data_length);
1313 		con->out_more = 1;  /* data + footer will follow */
1314 	} else {
1315 		/* no, queue up footer too and be done */
1316 		prepare_write_message_footer(con);
1317 	}
1318 
1319 	con_flag_set(con, CON_FLAG_WRITE_PENDING);
1320 }
1321 
1322 /*
1323  * Prepare an ack.
1324  */
1325 static void prepare_write_ack(struct ceph_connection *con)
1326 {
1327 	dout("prepare_write_ack %p %llu -> %llu\n", con,
1328 	     con->in_seq_acked, con->in_seq);
1329 	con->in_seq_acked = con->in_seq;
1330 
1331 	con_out_kvec_reset(con);
1332 
1333 	con_out_kvec_add(con, sizeof (tag_ack), &tag_ack);
1334 
1335 	con->out_temp_ack = cpu_to_le64(con->in_seq_acked);
1336 	con_out_kvec_add(con, sizeof (con->out_temp_ack),
1337 				&con->out_temp_ack);
1338 
1339 	con->out_more = 1;  /* more will follow.. eventually.. */
1340 	con_flag_set(con, CON_FLAG_WRITE_PENDING);
1341 }
1342 
1343 /*
1344  * Prepare to share the seq during handshake
1345  */
1346 static void prepare_write_seq(struct ceph_connection *con)
1347 {
1348 	dout("prepare_write_seq %p %llu -> %llu\n", con,
1349 	     con->in_seq_acked, con->in_seq);
1350 	con->in_seq_acked = con->in_seq;
1351 
1352 	con_out_kvec_reset(con);
1353 
1354 	con->out_temp_ack = cpu_to_le64(con->in_seq_acked);
1355 	con_out_kvec_add(con, sizeof (con->out_temp_ack),
1356 			 &con->out_temp_ack);
1357 
1358 	con_flag_set(con, CON_FLAG_WRITE_PENDING);
1359 }
1360 
1361 /*
1362  * Prepare to write keepalive byte.
1363  */
1364 static void prepare_write_keepalive(struct ceph_connection *con)
1365 {
1366 	dout("prepare_write_keepalive %p\n", con);
1367 	con_out_kvec_reset(con);
1368 	if (con->peer_features & CEPH_FEATURE_MSGR_KEEPALIVE2) {
1369 		struct timespec now = CURRENT_TIME;
1370 
1371 		con_out_kvec_add(con, sizeof(tag_keepalive2), &tag_keepalive2);
1372 		ceph_encode_timespec(&con->out_temp_keepalive2, &now);
1373 		con_out_kvec_add(con, sizeof(con->out_temp_keepalive2),
1374 				 &con->out_temp_keepalive2);
1375 	} else {
1376 		con_out_kvec_add(con, sizeof(tag_keepalive), &tag_keepalive);
1377 	}
1378 	con_flag_set(con, CON_FLAG_WRITE_PENDING);
1379 }
1380 
1381 /*
1382  * Connection negotiation.
1383  */
1384 
1385 static struct ceph_auth_handshake *get_connect_authorizer(struct ceph_connection *con,
1386 						int *auth_proto)
1387 {
1388 	struct ceph_auth_handshake *auth;
1389 
1390 	if (!con->ops->get_authorizer) {
1391 		con->out_connect.authorizer_protocol = CEPH_AUTH_UNKNOWN;
1392 		con->out_connect.authorizer_len = 0;
1393 		return NULL;
1394 	}
1395 
1396 	/* Can't hold the mutex while getting authorizer */
1397 	mutex_unlock(&con->mutex);
1398 	auth = con->ops->get_authorizer(con, auth_proto, con->auth_retry);
1399 	mutex_lock(&con->mutex);
1400 
1401 	if (IS_ERR(auth))
1402 		return auth;
1403 	if (con->state != CON_STATE_NEGOTIATING)
1404 		return ERR_PTR(-EAGAIN);
1405 
1406 	con->auth_reply_buf = auth->authorizer_reply_buf;
1407 	con->auth_reply_buf_len = auth->authorizer_reply_buf_len;
1408 	return auth;
1409 }
1410 
1411 /*
1412  * We connected to a peer and are saying hello.
1413  */
1414 static void prepare_write_banner(struct ceph_connection *con)
1415 {
1416 	con_out_kvec_add(con, strlen(CEPH_BANNER), CEPH_BANNER);
1417 	con_out_kvec_add(con, sizeof (con->msgr->my_enc_addr),
1418 					&con->msgr->my_enc_addr);
1419 
1420 	con->out_more = 0;
1421 	con_flag_set(con, CON_FLAG_WRITE_PENDING);
1422 }
1423 
1424 static int prepare_write_connect(struct ceph_connection *con)
1425 {
1426 	unsigned int global_seq = get_global_seq(con->msgr, 0);
1427 	int proto;
1428 	int auth_proto;
1429 	struct ceph_auth_handshake *auth;
1430 
1431 	switch (con->peer_name.type) {
1432 	case CEPH_ENTITY_TYPE_MON:
1433 		proto = CEPH_MONC_PROTOCOL;
1434 		break;
1435 	case CEPH_ENTITY_TYPE_OSD:
1436 		proto = CEPH_OSDC_PROTOCOL;
1437 		break;
1438 	case CEPH_ENTITY_TYPE_MDS:
1439 		proto = CEPH_MDSC_PROTOCOL;
1440 		break;
1441 	default:
1442 		BUG();
1443 	}
1444 
1445 	dout("prepare_write_connect %p cseq=%d gseq=%d proto=%d\n", con,
1446 	     con->connect_seq, global_seq, proto);
1447 
1448 	con->out_connect.features =
1449 	    cpu_to_le64(from_msgr(con->msgr)->supported_features);
1450 	con->out_connect.host_type = cpu_to_le32(CEPH_ENTITY_TYPE_CLIENT);
1451 	con->out_connect.connect_seq = cpu_to_le32(con->connect_seq);
1452 	con->out_connect.global_seq = cpu_to_le32(global_seq);
1453 	con->out_connect.protocol_version = cpu_to_le32(proto);
1454 	con->out_connect.flags = 0;
1455 
1456 	auth_proto = CEPH_AUTH_UNKNOWN;
1457 	auth = get_connect_authorizer(con, &auth_proto);
1458 	if (IS_ERR(auth))
1459 		return PTR_ERR(auth);
1460 
1461 	con->out_connect.authorizer_protocol = cpu_to_le32(auth_proto);
1462 	con->out_connect.authorizer_len = auth ?
1463 		cpu_to_le32(auth->authorizer_buf_len) : 0;
1464 
1465 	con_out_kvec_add(con, sizeof (con->out_connect),
1466 					&con->out_connect);
1467 	if (auth && auth->authorizer_buf_len)
1468 		con_out_kvec_add(con, auth->authorizer_buf_len,
1469 					auth->authorizer_buf);
1470 
1471 	con->out_more = 0;
1472 	con_flag_set(con, CON_FLAG_WRITE_PENDING);
1473 
1474 	return 0;
1475 }
1476 
1477 /*
1478  * write as much of pending kvecs to the socket as we can.
1479  *  1 -> done
1480  *  0 -> socket full, but more to do
1481  * <0 -> error
1482  */
1483 static int write_partial_kvec(struct ceph_connection *con)
1484 {
1485 	int ret;
1486 
1487 	dout("write_partial_kvec %p %d left\n", con, con->out_kvec_bytes);
1488 	while (con->out_kvec_bytes > 0) {
1489 		ret = ceph_tcp_sendmsg(con->sock, con->out_kvec_cur,
1490 				       con->out_kvec_left, con->out_kvec_bytes,
1491 				       con->out_more);
1492 		if (ret <= 0)
1493 			goto out;
1494 		con->out_kvec_bytes -= ret;
1495 		if (con->out_kvec_bytes == 0)
1496 			break;            /* done */
1497 
1498 		/* account for full iov entries consumed */
1499 		while (ret >= con->out_kvec_cur->iov_len) {
1500 			BUG_ON(!con->out_kvec_left);
1501 			ret -= con->out_kvec_cur->iov_len;
1502 			con->out_kvec_cur++;
1503 			con->out_kvec_left--;
1504 		}
1505 		/* and for a partially-consumed entry */
1506 		if (ret) {
1507 			con->out_kvec_cur->iov_len -= ret;
1508 			con->out_kvec_cur->iov_base += ret;
1509 		}
1510 	}
1511 	con->out_kvec_left = 0;
1512 	ret = 1;
1513 out:
1514 	dout("write_partial_kvec %p %d left in %d kvecs ret = %d\n", con,
1515 	     con->out_kvec_bytes, con->out_kvec_left, ret);
1516 	return ret;  /* done! */
1517 }
1518 
1519 static u32 ceph_crc32c_page(u32 crc, struct page *page,
1520 				unsigned int page_offset,
1521 				unsigned int length)
1522 {
1523 	char *kaddr;
1524 
1525 	kaddr = kmap(page);
1526 	BUG_ON(kaddr == NULL);
1527 	crc = crc32c(crc, kaddr + page_offset, length);
1528 	kunmap(page);
1529 
1530 	return crc;
1531 }
1532 /*
1533  * Write as much message data payload as we can.  If we finish, queue
1534  * up the footer.
1535  *  1 -> done, footer is now queued in out_kvec[].
1536  *  0 -> socket full, but more to do
1537  * <0 -> error
1538  */
1539 static int write_partial_message_data(struct ceph_connection *con)
1540 {
1541 	struct ceph_msg *msg = con->out_msg;
1542 	struct ceph_msg_data_cursor *cursor = &msg->cursor;
1543 	bool do_datacrc = !ceph_test_opt(from_msgr(con->msgr), NOCRC);
1544 	u32 crc;
1545 
1546 	dout("%s %p msg %p\n", __func__, con, msg);
1547 
1548 	if (list_empty(&msg->data))
1549 		return -EINVAL;
1550 
1551 	/*
1552 	 * Iterate through each page that contains data to be
1553 	 * written, and send as much as possible for each.
1554 	 *
1555 	 * If we are calculating the data crc (the default), we will
1556 	 * need to map the page.  If we have no pages, they have
1557 	 * been revoked, so use the zero page.
1558 	 */
1559 	crc = do_datacrc ? le32_to_cpu(msg->footer.data_crc) : 0;
1560 	while (cursor->resid) {
1561 		struct page *page;
1562 		size_t page_offset;
1563 		size_t length;
1564 		bool last_piece;
1565 		bool need_crc;
1566 		int ret;
1567 
1568 		page = ceph_msg_data_next(cursor, &page_offset, &length,
1569 					  &last_piece);
1570 		ret = ceph_tcp_sendpage(con->sock, page, page_offset,
1571 					length, !last_piece);
1572 		if (ret <= 0) {
1573 			if (do_datacrc)
1574 				msg->footer.data_crc = cpu_to_le32(crc);
1575 
1576 			return ret;
1577 		}
1578 		if (do_datacrc && cursor->need_crc)
1579 			crc = ceph_crc32c_page(crc, page, page_offset, length);
1580 		need_crc = ceph_msg_data_advance(cursor, (size_t)ret);
1581 	}
1582 
1583 	dout("%s %p msg %p done\n", __func__, con, msg);
1584 
1585 	/* prepare and queue up footer, too */
1586 	if (do_datacrc)
1587 		msg->footer.data_crc = cpu_to_le32(crc);
1588 	else
1589 		msg->footer.flags |= CEPH_MSG_FOOTER_NOCRC;
1590 	con_out_kvec_reset(con);
1591 	prepare_write_message_footer(con);
1592 
1593 	return 1;	/* must return > 0 to indicate success */
1594 }
1595 
1596 /*
1597  * write some zeros
1598  */
1599 static int write_partial_skip(struct ceph_connection *con)
1600 {
1601 	int ret;
1602 
1603 	dout("%s %p %d left\n", __func__, con, con->out_skip);
1604 	while (con->out_skip > 0) {
1605 		size_t size = min(con->out_skip, (int) PAGE_SIZE);
1606 
1607 		ret = ceph_tcp_sendpage(con->sock, zero_page, 0, size, true);
1608 		if (ret <= 0)
1609 			goto out;
1610 		con->out_skip -= ret;
1611 	}
1612 	ret = 1;
1613 out:
1614 	return ret;
1615 }
1616 
1617 /*
1618  * Prepare to read connection handshake, or an ack.
1619  */
1620 static void prepare_read_banner(struct ceph_connection *con)
1621 {
1622 	dout("prepare_read_banner %p\n", con);
1623 	con->in_base_pos = 0;
1624 }
1625 
1626 static void prepare_read_connect(struct ceph_connection *con)
1627 {
1628 	dout("prepare_read_connect %p\n", con);
1629 	con->in_base_pos = 0;
1630 }
1631 
1632 static void prepare_read_ack(struct ceph_connection *con)
1633 {
1634 	dout("prepare_read_ack %p\n", con);
1635 	con->in_base_pos = 0;
1636 }
1637 
1638 static void prepare_read_seq(struct ceph_connection *con)
1639 {
1640 	dout("prepare_read_seq %p\n", con);
1641 	con->in_base_pos = 0;
1642 	con->in_tag = CEPH_MSGR_TAG_SEQ;
1643 }
1644 
1645 static void prepare_read_tag(struct ceph_connection *con)
1646 {
1647 	dout("prepare_read_tag %p\n", con);
1648 	con->in_base_pos = 0;
1649 	con->in_tag = CEPH_MSGR_TAG_READY;
1650 }
1651 
1652 static void prepare_read_keepalive_ack(struct ceph_connection *con)
1653 {
1654 	dout("prepare_read_keepalive_ack %p\n", con);
1655 	con->in_base_pos = 0;
1656 }
1657 
1658 /*
1659  * Prepare to read a message.
1660  */
1661 static int prepare_read_message(struct ceph_connection *con)
1662 {
1663 	dout("prepare_read_message %p\n", con);
1664 	BUG_ON(con->in_msg != NULL);
1665 	con->in_base_pos = 0;
1666 	con->in_front_crc = con->in_middle_crc = con->in_data_crc = 0;
1667 	return 0;
1668 }
1669 
1670 
1671 static int read_partial(struct ceph_connection *con,
1672 			int end, int size, void *object)
1673 {
1674 	while (con->in_base_pos < end) {
1675 		int left = end - con->in_base_pos;
1676 		int have = size - left;
1677 		int ret = ceph_tcp_recvmsg(con->sock, object + have, left);
1678 		if (ret <= 0)
1679 			return ret;
1680 		con->in_base_pos += ret;
1681 	}
1682 	return 1;
1683 }
1684 
1685 
1686 /*
1687  * Read all or part of the connect-side handshake on a new connection
1688  */
1689 static int read_partial_banner(struct ceph_connection *con)
1690 {
1691 	int size;
1692 	int end;
1693 	int ret;
1694 
1695 	dout("read_partial_banner %p at %d\n", con, con->in_base_pos);
1696 
1697 	/* peer's banner */
1698 	size = strlen(CEPH_BANNER);
1699 	end = size;
1700 	ret = read_partial(con, end, size, con->in_banner);
1701 	if (ret <= 0)
1702 		goto out;
1703 
1704 	size = sizeof (con->actual_peer_addr);
1705 	end += size;
1706 	ret = read_partial(con, end, size, &con->actual_peer_addr);
1707 	if (ret <= 0)
1708 		goto out;
1709 
1710 	size = sizeof (con->peer_addr_for_me);
1711 	end += size;
1712 	ret = read_partial(con, end, size, &con->peer_addr_for_me);
1713 	if (ret <= 0)
1714 		goto out;
1715 
1716 out:
1717 	return ret;
1718 }
1719 
1720 static int read_partial_connect(struct ceph_connection *con)
1721 {
1722 	int size;
1723 	int end;
1724 	int ret;
1725 
1726 	dout("read_partial_connect %p at %d\n", con, con->in_base_pos);
1727 
1728 	size = sizeof (con->in_reply);
1729 	end = size;
1730 	ret = read_partial(con, end, size, &con->in_reply);
1731 	if (ret <= 0)
1732 		goto out;
1733 
1734 	size = le32_to_cpu(con->in_reply.authorizer_len);
1735 	end += size;
1736 	ret = read_partial(con, end, size, con->auth_reply_buf);
1737 	if (ret <= 0)
1738 		goto out;
1739 
1740 	dout("read_partial_connect %p tag %d, con_seq = %u, g_seq = %u\n",
1741 	     con, (int)con->in_reply.tag,
1742 	     le32_to_cpu(con->in_reply.connect_seq),
1743 	     le32_to_cpu(con->in_reply.global_seq));
1744 out:
1745 	return ret;
1746 
1747 }
1748 
1749 /*
1750  * Verify the hello banner looks okay.
1751  */
1752 static int verify_hello(struct ceph_connection *con)
1753 {
1754 	if (memcmp(con->in_banner, CEPH_BANNER, strlen(CEPH_BANNER))) {
1755 		pr_err("connect to %s got bad banner\n",
1756 		       ceph_pr_addr(&con->peer_addr.in_addr));
1757 		con->error_msg = "protocol error, bad banner";
1758 		return -1;
1759 	}
1760 	return 0;
1761 }
1762 
1763 static bool addr_is_blank(struct sockaddr_storage *ss)
1764 {
1765 	struct in_addr *addr = &((struct sockaddr_in *)ss)->sin_addr;
1766 	struct in6_addr *addr6 = &((struct sockaddr_in6 *)ss)->sin6_addr;
1767 
1768 	switch (ss->ss_family) {
1769 	case AF_INET:
1770 		return addr->s_addr == htonl(INADDR_ANY);
1771 	case AF_INET6:
1772 		return ipv6_addr_any(addr6);
1773 	default:
1774 		return true;
1775 	}
1776 }
1777 
1778 static int addr_port(struct sockaddr_storage *ss)
1779 {
1780 	switch (ss->ss_family) {
1781 	case AF_INET:
1782 		return ntohs(((struct sockaddr_in *)ss)->sin_port);
1783 	case AF_INET6:
1784 		return ntohs(((struct sockaddr_in6 *)ss)->sin6_port);
1785 	}
1786 	return 0;
1787 }
1788 
1789 static void addr_set_port(struct sockaddr_storage *ss, int p)
1790 {
1791 	switch (ss->ss_family) {
1792 	case AF_INET:
1793 		((struct sockaddr_in *)ss)->sin_port = htons(p);
1794 		break;
1795 	case AF_INET6:
1796 		((struct sockaddr_in6 *)ss)->sin6_port = htons(p);
1797 		break;
1798 	}
1799 }
1800 
1801 /*
1802  * Unlike other *_pton function semantics, zero indicates success.
1803  */
1804 static int ceph_pton(const char *str, size_t len, struct sockaddr_storage *ss,
1805 		char delim, const char **ipend)
1806 {
1807 	struct sockaddr_in *in4 = (struct sockaddr_in *) ss;
1808 	struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) ss;
1809 
1810 	memset(ss, 0, sizeof(*ss));
1811 
1812 	if (in4_pton(str, len, (u8 *)&in4->sin_addr.s_addr, delim, ipend)) {
1813 		ss->ss_family = AF_INET;
1814 		return 0;
1815 	}
1816 
1817 	if (in6_pton(str, len, (u8 *)&in6->sin6_addr.s6_addr, delim, ipend)) {
1818 		ss->ss_family = AF_INET6;
1819 		return 0;
1820 	}
1821 
1822 	return -EINVAL;
1823 }
1824 
1825 /*
1826  * Extract hostname string and resolve using kernel DNS facility.
1827  */
1828 #ifdef CONFIG_CEPH_LIB_USE_DNS_RESOLVER
1829 static int ceph_dns_resolve_name(const char *name, size_t namelen,
1830 		struct sockaddr_storage *ss, char delim, const char **ipend)
1831 {
1832 	const char *end, *delim_p;
1833 	char *colon_p, *ip_addr = NULL;
1834 	int ip_len, ret;
1835 
1836 	/*
1837 	 * The end of the hostname occurs immediately preceding the delimiter or
1838 	 * the port marker (':') where the delimiter takes precedence.
1839 	 */
1840 	delim_p = memchr(name, delim, namelen);
1841 	colon_p = memchr(name, ':', namelen);
1842 
1843 	if (delim_p && colon_p)
1844 		end = delim_p < colon_p ? delim_p : colon_p;
1845 	else if (!delim_p && colon_p)
1846 		end = colon_p;
1847 	else {
1848 		end = delim_p;
1849 		if (!end) /* case: hostname:/ */
1850 			end = name + namelen;
1851 	}
1852 
1853 	if (end <= name)
1854 		return -EINVAL;
1855 
1856 	/* do dns_resolve upcall */
1857 	ip_len = dns_query(NULL, name, end - name, NULL, &ip_addr, NULL);
1858 	if (ip_len > 0)
1859 		ret = ceph_pton(ip_addr, ip_len, ss, -1, NULL);
1860 	else
1861 		ret = -ESRCH;
1862 
1863 	kfree(ip_addr);
1864 
1865 	*ipend = end;
1866 
1867 	pr_info("resolve '%.*s' (ret=%d): %s\n", (int)(end - name), name,
1868 			ret, ret ? "failed" : ceph_pr_addr(ss));
1869 
1870 	return ret;
1871 }
1872 #else
1873 static inline int ceph_dns_resolve_name(const char *name, size_t namelen,
1874 		struct sockaddr_storage *ss, char delim, const char **ipend)
1875 {
1876 	return -EINVAL;
1877 }
1878 #endif
1879 
1880 /*
1881  * Parse a server name (IP or hostname). If a valid IP address is not found
1882  * then try to extract a hostname to resolve using userspace DNS upcall.
1883  */
1884 static int ceph_parse_server_name(const char *name, size_t namelen,
1885 			struct sockaddr_storage *ss, char delim, const char **ipend)
1886 {
1887 	int ret;
1888 
1889 	ret = ceph_pton(name, namelen, ss, delim, ipend);
1890 	if (ret)
1891 		ret = ceph_dns_resolve_name(name, namelen, ss, delim, ipend);
1892 
1893 	return ret;
1894 }
1895 
1896 /*
1897  * Parse an ip[:port] list into an addr array.  Use the default
1898  * monitor port if a port isn't specified.
1899  */
1900 int ceph_parse_ips(const char *c, const char *end,
1901 		   struct ceph_entity_addr *addr,
1902 		   int max_count, int *count)
1903 {
1904 	int i, ret = -EINVAL;
1905 	const char *p = c;
1906 
1907 	dout("parse_ips on '%.*s'\n", (int)(end-c), c);
1908 	for (i = 0; i < max_count; i++) {
1909 		const char *ipend;
1910 		struct sockaddr_storage *ss = &addr[i].in_addr;
1911 		int port;
1912 		char delim = ',';
1913 
1914 		if (*p == '[') {
1915 			delim = ']';
1916 			p++;
1917 		}
1918 
1919 		ret = ceph_parse_server_name(p, end - p, ss, delim, &ipend);
1920 		if (ret)
1921 			goto bad;
1922 		ret = -EINVAL;
1923 
1924 		p = ipend;
1925 
1926 		if (delim == ']') {
1927 			if (*p != ']') {
1928 				dout("missing matching ']'\n");
1929 				goto bad;
1930 			}
1931 			p++;
1932 		}
1933 
1934 		/* port? */
1935 		if (p < end && *p == ':') {
1936 			port = 0;
1937 			p++;
1938 			while (p < end && *p >= '0' && *p <= '9') {
1939 				port = (port * 10) + (*p - '0');
1940 				p++;
1941 			}
1942 			if (port == 0)
1943 				port = CEPH_MON_PORT;
1944 			else if (port > 65535)
1945 				goto bad;
1946 		} else {
1947 			port = CEPH_MON_PORT;
1948 		}
1949 
1950 		addr_set_port(ss, port);
1951 
1952 		dout("parse_ips got %s\n", ceph_pr_addr(ss));
1953 
1954 		if (p == end)
1955 			break;
1956 		if (*p != ',')
1957 			goto bad;
1958 		p++;
1959 	}
1960 
1961 	if (p != end)
1962 		goto bad;
1963 
1964 	if (count)
1965 		*count = i + 1;
1966 	return 0;
1967 
1968 bad:
1969 	pr_err("parse_ips bad ip '%.*s'\n", (int)(end - c), c);
1970 	return ret;
1971 }
1972 EXPORT_SYMBOL(ceph_parse_ips);
1973 
1974 static int process_banner(struct ceph_connection *con)
1975 {
1976 	dout("process_banner on %p\n", con);
1977 
1978 	if (verify_hello(con) < 0)
1979 		return -1;
1980 
1981 	ceph_decode_addr(&con->actual_peer_addr);
1982 	ceph_decode_addr(&con->peer_addr_for_me);
1983 
1984 	/*
1985 	 * Make sure the other end is who we wanted.  note that the other
1986 	 * end may not yet know their ip address, so if it's 0.0.0.0, give
1987 	 * them the benefit of the doubt.
1988 	 */
1989 	if (memcmp(&con->peer_addr, &con->actual_peer_addr,
1990 		   sizeof(con->peer_addr)) != 0 &&
1991 	    !(addr_is_blank(&con->actual_peer_addr.in_addr) &&
1992 	      con->actual_peer_addr.nonce == con->peer_addr.nonce)) {
1993 		pr_warn("wrong peer, want %s/%d, got %s/%d\n",
1994 			ceph_pr_addr(&con->peer_addr.in_addr),
1995 			(int)le32_to_cpu(con->peer_addr.nonce),
1996 			ceph_pr_addr(&con->actual_peer_addr.in_addr),
1997 			(int)le32_to_cpu(con->actual_peer_addr.nonce));
1998 		con->error_msg = "wrong peer at address";
1999 		return -1;
2000 	}
2001 
2002 	/*
2003 	 * did we learn our address?
2004 	 */
2005 	if (addr_is_blank(&con->msgr->inst.addr.in_addr)) {
2006 		int port = addr_port(&con->msgr->inst.addr.in_addr);
2007 
2008 		memcpy(&con->msgr->inst.addr.in_addr,
2009 		       &con->peer_addr_for_me.in_addr,
2010 		       sizeof(con->peer_addr_for_me.in_addr));
2011 		addr_set_port(&con->msgr->inst.addr.in_addr, port);
2012 		encode_my_addr(con->msgr);
2013 		dout("process_banner learned my addr is %s\n",
2014 		     ceph_pr_addr(&con->msgr->inst.addr.in_addr));
2015 	}
2016 
2017 	return 0;
2018 }
2019 
2020 static int process_connect(struct ceph_connection *con)
2021 {
2022 	u64 sup_feat = from_msgr(con->msgr)->supported_features;
2023 	u64 req_feat = from_msgr(con->msgr)->required_features;
2024 	u64 server_feat = ceph_sanitize_features(
2025 				le64_to_cpu(con->in_reply.features));
2026 	int ret;
2027 
2028 	dout("process_connect on %p tag %d\n", con, (int)con->in_tag);
2029 
2030 	switch (con->in_reply.tag) {
2031 	case CEPH_MSGR_TAG_FEATURES:
2032 		pr_err("%s%lld %s feature set mismatch,"
2033 		       " my %llx < server's %llx, missing %llx\n",
2034 		       ENTITY_NAME(con->peer_name),
2035 		       ceph_pr_addr(&con->peer_addr.in_addr),
2036 		       sup_feat, server_feat, server_feat & ~sup_feat);
2037 		con->error_msg = "missing required protocol features";
2038 		reset_connection(con);
2039 		return -1;
2040 
2041 	case CEPH_MSGR_TAG_BADPROTOVER:
2042 		pr_err("%s%lld %s protocol version mismatch,"
2043 		       " my %d != server's %d\n",
2044 		       ENTITY_NAME(con->peer_name),
2045 		       ceph_pr_addr(&con->peer_addr.in_addr),
2046 		       le32_to_cpu(con->out_connect.protocol_version),
2047 		       le32_to_cpu(con->in_reply.protocol_version));
2048 		con->error_msg = "protocol version mismatch";
2049 		reset_connection(con);
2050 		return -1;
2051 
2052 	case CEPH_MSGR_TAG_BADAUTHORIZER:
2053 		con->auth_retry++;
2054 		dout("process_connect %p got BADAUTHORIZER attempt %d\n", con,
2055 		     con->auth_retry);
2056 		if (con->auth_retry == 2) {
2057 			con->error_msg = "connect authorization failure";
2058 			return -1;
2059 		}
2060 		con_out_kvec_reset(con);
2061 		ret = prepare_write_connect(con);
2062 		if (ret < 0)
2063 			return ret;
2064 		prepare_read_connect(con);
2065 		break;
2066 
2067 	case CEPH_MSGR_TAG_RESETSESSION:
2068 		/*
2069 		 * If we connected with a large connect_seq but the peer
2070 		 * has no record of a session with us (no connection, or
2071 		 * connect_seq == 0), they will send RESETSESION to indicate
2072 		 * that they must have reset their session, and may have
2073 		 * dropped messages.
2074 		 */
2075 		dout("process_connect got RESET peer seq %u\n",
2076 		     le32_to_cpu(con->in_reply.connect_seq));
2077 		pr_err("%s%lld %s connection reset\n",
2078 		       ENTITY_NAME(con->peer_name),
2079 		       ceph_pr_addr(&con->peer_addr.in_addr));
2080 		reset_connection(con);
2081 		con_out_kvec_reset(con);
2082 		ret = prepare_write_connect(con);
2083 		if (ret < 0)
2084 			return ret;
2085 		prepare_read_connect(con);
2086 
2087 		/* Tell ceph about it. */
2088 		mutex_unlock(&con->mutex);
2089 		pr_info("reset on %s%lld\n", ENTITY_NAME(con->peer_name));
2090 		if (con->ops->peer_reset)
2091 			con->ops->peer_reset(con);
2092 		mutex_lock(&con->mutex);
2093 		if (con->state != CON_STATE_NEGOTIATING)
2094 			return -EAGAIN;
2095 		break;
2096 
2097 	case CEPH_MSGR_TAG_RETRY_SESSION:
2098 		/*
2099 		 * If we sent a smaller connect_seq than the peer has, try
2100 		 * again with a larger value.
2101 		 */
2102 		dout("process_connect got RETRY_SESSION my seq %u, peer %u\n",
2103 		     le32_to_cpu(con->out_connect.connect_seq),
2104 		     le32_to_cpu(con->in_reply.connect_seq));
2105 		con->connect_seq = le32_to_cpu(con->in_reply.connect_seq);
2106 		con_out_kvec_reset(con);
2107 		ret = prepare_write_connect(con);
2108 		if (ret < 0)
2109 			return ret;
2110 		prepare_read_connect(con);
2111 		break;
2112 
2113 	case CEPH_MSGR_TAG_RETRY_GLOBAL:
2114 		/*
2115 		 * If we sent a smaller global_seq than the peer has, try
2116 		 * again with a larger value.
2117 		 */
2118 		dout("process_connect got RETRY_GLOBAL my %u peer_gseq %u\n",
2119 		     con->peer_global_seq,
2120 		     le32_to_cpu(con->in_reply.global_seq));
2121 		get_global_seq(con->msgr,
2122 			       le32_to_cpu(con->in_reply.global_seq));
2123 		con_out_kvec_reset(con);
2124 		ret = prepare_write_connect(con);
2125 		if (ret < 0)
2126 			return ret;
2127 		prepare_read_connect(con);
2128 		break;
2129 
2130 	case CEPH_MSGR_TAG_SEQ:
2131 	case CEPH_MSGR_TAG_READY:
2132 		if (req_feat & ~server_feat) {
2133 			pr_err("%s%lld %s protocol feature mismatch,"
2134 			       " my required %llx > server's %llx, need %llx\n",
2135 			       ENTITY_NAME(con->peer_name),
2136 			       ceph_pr_addr(&con->peer_addr.in_addr),
2137 			       req_feat, server_feat, req_feat & ~server_feat);
2138 			con->error_msg = "missing required protocol features";
2139 			reset_connection(con);
2140 			return -1;
2141 		}
2142 
2143 		WARN_ON(con->state != CON_STATE_NEGOTIATING);
2144 		con->state = CON_STATE_OPEN;
2145 		con->auth_retry = 0;    /* we authenticated; clear flag */
2146 		con->peer_global_seq = le32_to_cpu(con->in_reply.global_seq);
2147 		con->connect_seq++;
2148 		con->peer_features = server_feat;
2149 		dout("process_connect got READY gseq %d cseq %d (%d)\n",
2150 		     con->peer_global_seq,
2151 		     le32_to_cpu(con->in_reply.connect_seq),
2152 		     con->connect_seq);
2153 		WARN_ON(con->connect_seq !=
2154 			le32_to_cpu(con->in_reply.connect_seq));
2155 
2156 		if (con->in_reply.flags & CEPH_MSG_CONNECT_LOSSY)
2157 			con_flag_set(con, CON_FLAG_LOSSYTX);
2158 
2159 		con->delay = 0;      /* reset backoff memory */
2160 
2161 		if (con->in_reply.tag == CEPH_MSGR_TAG_SEQ) {
2162 			prepare_write_seq(con);
2163 			prepare_read_seq(con);
2164 		} else {
2165 			prepare_read_tag(con);
2166 		}
2167 		break;
2168 
2169 	case CEPH_MSGR_TAG_WAIT:
2170 		/*
2171 		 * If there is a connection race (we are opening
2172 		 * connections to each other), one of us may just have
2173 		 * to WAIT.  This shouldn't happen if we are the
2174 		 * client.
2175 		 */
2176 		con->error_msg = "protocol error, got WAIT as client";
2177 		return -1;
2178 
2179 	default:
2180 		con->error_msg = "protocol error, garbage tag during connect";
2181 		return -1;
2182 	}
2183 	return 0;
2184 }
2185 
2186 
2187 /*
2188  * read (part of) an ack
2189  */
2190 static int read_partial_ack(struct ceph_connection *con)
2191 {
2192 	int size = sizeof (con->in_temp_ack);
2193 	int end = size;
2194 
2195 	return read_partial(con, end, size, &con->in_temp_ack);
2196 }
2197 
2198 /*
2199  * We can finally discard anything that's been acked.
2200  */
2201 static void process_ack(struct ceph_connection *con)
2202 {
2203 	struct ceph_msg *m;
2204 	u64 ack = le64_to_cpu(con->in_temp_ack);
2205 	u64 seq;
2206 
2207 	while (!list_empty(&con->out_sent)) {
2208 		m = list_first_entry(&con->out_sent, struct ceph_msg,
2209 				     list_head);
2210 		seq = le64_to_cpu(m->hdr.seq);
2211 		if (seq > ack)
2212 			break;
2213 		dout("got ack for seq %llu type %d at %p\n", seq,
2214 		     le16_to_cpu(m->hdr.type), m);
2215 		m->ack_stamp = jiffies;
2216 		ceph_msg_remove(m);
2217 	}
2218 	prepare_read_tag(con);
2219 }
2220 
2221 
2222 static int read_partial_message_section(struct ceph_connection *con,
2223 					struct kvec *section,
2224 					unsigned int sec_len, u32 *crc)
2225 {
2226 	int ret, left;
2227 
2228 	BUG_ON(!section);
2229 
2230 	while (section->iov_len < sec_len) {
2231 		BUG_ON(section->iov_base == NULL);
2232 		left = sec_len - section->iov_len;
2233 		ret = ceph_tcp_recvmsg(con->sock, (char *)section->iov_base +
2234 				       section->iov_len, left);
2235 		if (ret <= 0)
2236 			return ret;
2237 		section->iov_len += ret;
2238 	}
2239 	if (section->iov_len == sec_len)
2240 		*crc = crc32c(0, section->iov_base, section->iov_len);
2241 
2242 	return 1;
2243 }
2244 
2245 static int read_partial_msg_data(struct ceph_connection *con)
2246 {
2247 	struct ceph_msg *msg = con->in_msg;
2248 	struct ceph_msg_data_cursor *cursor = &msg->cursor;
2249 	bool do_datacrc = !ceph_test_opt(from_msgr(con->msgr), NOCRC);
2250 	struct page *page;
2251 	size_t page_offset;
2252 	size_t length;
2253 	u32 crc = 0;
2254 	int ret;
2255 
2256 	BUG_ON(!msg);
2257 	if (list_empty(&msg->data))
2258 		return -EIO;
2259 
2260 	if (do_datacrc)
2261 		crc = con->in_data_crc;
2262 	while (cursor->resid) {
2263 		page = ceph_msg_data_next(cursor, &page_offset, &length, NULL);
2264 		ret = ceph_tcp_recvpage(con->sock, page, page_offset, length);
2265 		if (ret <= 0) {
2266 			if (do_datacrc)
2267 				con->in_data_crc = crc;
2268 
2269 			return ret;
2270 		}
2271 
2272 		if (do_datacrc)
2273 			crc = ceph_crc32c_page(crc, page, page_offset, ret);
2274 		(void) ceph_msg_data_advance(cursor, (size_t)ret);
2275 	}
2276 	if (do_datacrc)
2277 		con->in_data_crc = crc;
2278 
2279 	return 1;	/* must return > 0 to indicate success */
2280 }
2281 
2282 /*
2283  * read (part of) a message.
2284  */
2285 static int ceph_con_in_msg_alloc(struct ceph_connection *con, int *skip);
2286 
2287 static int read_partial_message(struct ceph_connection *con)
2288 {
2289 	struct ceph_msg *m = con->in_msg;
2290 	int size;
2291 	int end;
2292 	int ret;
2293 	unsigned int front_len, middle_len, data_len;
2294 	bool do_datacrc = !ceph_test_opt(from_msgr(con->msgr), NOCRC);
2295 	bool need_sign = (con->peer_features & CEPH_FEATURE_MSG_AUTH);
2296 	u64 seq;
2297 	u32 crc;
2298 
2299 	dout("read_partial_message con %p msg %p\n", con, m);
2300 
2301 	/* header */
2302 	size = sizeof (con->in_hdr);
2303 	end = size;
2304 	ret = read_partial(con, end, size, &con->in_hdr);
2305 	if (ret <= 0)
2306 		return ret;
2307 
2308 	crc = crc32c(0, &con->in_hdr, offsetof(struct ceph_msg_header, crc));
2309 	if (cpu_to_le32(crc) != con->in_hdr.crc) {
2310 		pr_err("read_partial_message bad hdr crc %u != expected %u\n",
2311 		       crc, con->in_hdr.crc);
2312 		return -EBADMSG;
2313 	}
2314 
2315 	front_len = le32_to_cpu(con->in_hdr.front_len);
2316 	if (front_len > CEPH_MSG_MAX_FRONT_LEN)
2317 		return -EIO;
2318 	middle_len = le32_to_cpu(con->in_hdr.middle_len);
2319 	if (middle_len > CEPH_MSG_MAX_MIDDLE_LEN)
2320 		return -EIO;
2321 	data_len = le32_to_cpu(con->in_hdr.data_len);
2322 	if (data_len > CEPH_MSG_MAX_DATA_LEN)
2323 		return -EIO;
2324 
2325 	/* verify seq# */
2326 	seq = le64_to_cpu(con->in_hdr.seq);
2327 	if ((s64)seq - (s64)con->in_seq < 1) {
2328 		pr_info("skipping %s%lld %s seq %lld expected %lld\n",
2329 			ENTITY_NAME(con->peer_name),
2330 			ceph_pr_addr(&con->peer_addr.in_addr),
2331 			seq, con->in_seq + 1);
2332 		con->in_base_pos = -front_len - middle_len - data_len -
2333 			sizeof_footer(con);
2334 		con->in_tag = CEPH_MSGR_TAG_READY;
2335 		return 1;
2336 	} else if ((s64)seq - (s64)con->in_seq > 1) {
2337 		pr_err("read_partial_message bad seq %lld expected %lld\n",
2338 		       seq, con->in_seq + 1);
2339 		con->error_msg = "bad message sequence # for incoming message";
2340 		return -EBADE;
2341 	}
2342 
2343 	/* allocate message? */
2344 	if (!con->in_msg) {
2345 		int skip = 0;
2346 
2347 		dout("got hdr type %d front %d data %d\n", con->in_hdr.type,
2348 		     front_len, data_len);
2349 		ret = ceph_con_in_msg_alloc(con, &skip);
2350 		if (ret < 0)
2351 			return ret;
2352 
2353 		BUG_ON(!con->in_msg ^ skip);
2354 		if (skip) {
2355 			/* skip this message */
2356 			dout("alloc_msg said skip message\n");
2357 			con->in_base_pos = -front_len - middle_len - data_len -
2358 				sizeof_footer(con);
2359 			con->in_tag = CEPH_MSGR_TAG_READY;
2360 			con->in_seq++;
2361 			return 1;
2362 		}
2363 
2364 		BUG_ON(!con->in_msg);
2365 		BUG_ON(con->in_msg->con != con);
2366 		m = con->in_msg;
2367 		m->front.iov_len = 0;    /* haven't read it yet */
2368 		if (m->middle)
2369 			m->middle->vec.iov_len = 0;
2370 
2371 		/* prepare for data payload, if any */
2372 
2373 		if (data_len)
2374 			prepare_message_data(con->in_msg, data_len);
2375 	}
2376 
2377 	/* front */
2378 	ret = read_partial_message_section(con, &m->front, front_len,
2379 					   &con->in_front_crc);
2380 	if (ret <= 0)
2381 		return ret;
2382 
2383 	/* middle */
2384 	if (m->middle) {
2385 		ret = read_partial_message_section(con, &m->middle->vec,
2386 						   middle_len,
2387 						   &con->in_middle_crc);
2388 		if (ret <= 0)
2389 			return ret;
2390 	}
2391 
2392 	/* (page) data */
2393 	if (data_len) {
2394 		ret = read_partial_msg_data(con);
2395 		if (ret <= 0)
2396 			return ret;
2397 	}
2398 
2399 	/* footer */
2400 	size = sizeof_footer(con);
2401 	end += size;
2402 	ret = read_partial(con, end, size, &m->footer);
2403 	if (ret <= 0)
2404 		return ret;
2405 
2406 	if (!need_sign) {
2407 		m->footer.flags = m->old_footer.flags;
2408 		m->footer.sig = 0;
2409 	}
2410 
2411 	dout("read_partial_message got msg %p %d (%u) + %d (%u) + %d (%u)\n",
2412 	     m, front_len, m->footer.front_crc, middle_len,
2413 	     m->footer.middle_crc, data_len, m->footer.data_crc);
2414 
2415 	/* crc ok? */
2416 	if (con->in_front_crc != le32_to_cpu(m->footer.front_crc)) {
2417 		pr_err("read_partial_message %p front crc %u != exp. %u\n",
2418 		       m, con->in_front_crc, m->footer.front_crc);
2419 		return -EBADMSG;
2420 	}
2421 	if (con->in_middle_crc != le32_to_cpu(m->footer.middle_crc)) {
2422 		pr_err("read_partial_message %p middle crc %u != exp %u\n",
2423 		       m, con->in_middle_crc, m->footer.middle_crc);
2424 		return -EBADMSG;
2425 	}
2426 	if (do_datacrc &&
2427 	    (m->footer.flags & CEPH_MSG_FOOTER_NOCRC) == 0 &&
2428 	    con->in_data_crc != le32_to_cpu(m->footer.data_crc)) {
2429 		pr_err("read_partial_message %p data crc %u != exp. %u\n", m,
2430 		       con->in_data_crc, le32_to_cpu(m->footer.data_crc));
2431 		return -EBADMSG;
2432 	}
2433 
2434 	if (need_sign && con->ops->check_message_signature &&
2435 	    con->ops->check_message_signature(m)) {
2436 		pr_err("read_partial_message %p signature check failed\n", m);
2437 		return -EBADMSG;
2438 	}
2439 
2440 	return 1; /* done! */
2441 }
2442 
2443 /*
2444  * Process message.  This happens in the worker thread.  The callback should
2445  * be careful not to do anything that waits on other incoming messages or it
2446  * may deadlock.
2447  */
2448 static void process_message(struct ceph_connection *con)
2449 {
2450 	struct ceph_msg *msg = con->in_msg;
2451 
2452 	BUG_ON(con->in_msg->con != con);
2453 	con->in_msg = NULL;
2454 
2455 	/* if first message, set peer_name */
2456 	if (con->peer_name.type == 0)
2457 		con->peer_name = msg->hdr.src;
2458 
2459 	con->in_seq++;
2460 	mutex_unlock(&con->mutex);
2461 
2462 	dout("===== %p %llu from %s%lld %d=%s len %d+%d (%u %u %u) =====\n",
2463 	     msg, le64_to_cpu(msg->hdr.seq),
2464 	     ENTITY_NAME(msg->hdr.src),
2465 	     le16_to_cpu(msg->hdr.type),
2466 	     ceph_msg_type_name(le16_to_cpu(msg->hdr.type)),
2467 	     le32_to_cpu(msg->hdr.front_len),
2468 	     le32_to_cpu(msg->hdr.data_len),
2469 	     con->in_front_crc, con->in_middle_crc, con->in_data_crc);
2470 	con->ops->dispatch(con, msg);
2471 
2472 	mutex_lock(&con->mutex);
2473 }
2474 
2475 static int read_keepalive_ack(struct ceph_connection *con)
2476 {
2477 	struct ceph_timespec ceph_ts;
2478 	size_t size = sizeof(ceph_ts);
2479 	int ret = read_partial(con, size, size, &ceph_ts);
2480 	if (ret <= 0)
2481 		return ret;
2482 	ceph_decode_timespec(&con->last_keepalive_ack, &ceph_ts);
2483 	prepare_read_tag(con);
2484 	return 1;
2485 }
2486 
2487 /*
2488  * Write something to the socket.  Called in a worker thread when the
2489  * socket appears to be writeable and we have something ready to send.
2490  */
2491 static int try_write(struct ceph_connection *con)
2492 {
2493 	int ret = 1;
2494 
2495 	dout("try_write start %p state %lu\n", con, con->state);
2496 
2497 more:
2498 	dout("try_write out_kvec_bytes %d\n", con->out_kvec_bytes);
2499 
2500 	/* open the socket first? */
2501 	if (con->state == CON_STATE_PREOPEN) {
2502 		BUG_ON(con->sock);
2503 		con->state = CON_STATE_CONNECTING;
2504 
2505 		con_out_kvec_reset(con);
2506 		prepare_write_banner(con);
2507 		prepare_read_banner(con);
2508 
2509 		BUG_ON(con->in_msg);
2510 		con->in_tag = CEPH_MSGR_TAG_READY;
2511 		dout("try_write initiating connect on %p new state %lu\n",
2512 		     con, con->state);
2513 		ret = ceph_tcp_connect(con);
2514 		if (ret < 0) {
2515 			con->error_msg = "connect error";
2516 			goto out;
2517 		}
2518 	}
2519 
2520 more_kvec:
2521 	/* kvec data queued? */
2522 	if (con->out_kvec_left) {
2523 		ret = write_partial_kvec(con);
2524 		if (ret <= 0)
2525 			goto out;
2526 	}
2527 	if (con->out_skip) {
2528 		ret = write_partial_skip(con);
2529 		if (ret <= 0)
2530 			goto out;
2531 	}
2532 
2533 	/* msg pages? */
2534 	if (con->out_msg) {
2535 		if (con->out_msg_done) {
2536 			ceph_msg_put(con->out_msg);
2537 			con->out_msg = NULL;   /* we're done with this one */
2538 			goto do_next;
2539 		}
2540 
2541 		ret = write_partial_message_data(con);
2542 		if (ret == 1)
2543 			goto more_kvec;  /* we need to send the footer, too! */
2544 		if (ret == 0)
2545 			goto out;
2546 		if (ret < 0) {
2547 			dout("try_write write_partial_message_data err %d\n",
2548 			     ret);
2549 			goto out;
2550 		}
2551 	}
2552 
2553 do_next:
2554 	if (con->state == CON_STATE_OPEN) {
2555 		if (con_flag_test_and_clear(con, CON_FLAG_KEEPALIVE_PENDING)) {
2556 			prepare_write_keepalive(con);
2557 			goto more;
2558 		}
2559 		/* is anything else pending? */
2560 		if (!list_empty(&con->out_queue)) {
2561 			prepare_write_message(con);
2562 			goto more;
2563 		}
2564 		if (con->in_seq > con->in_seq_acked) {
2565 			prepare_write_ack(con);
2566 			goto more;
2567 		}
2568 	}
2569 
2570 	/* Nothing to do! */
2571 	con_flag_clear(con, CON_FLAG_WRITE_PENDING);
2572 	dout("try_write nothing else to write.\n");
2573 	ret = 0;
2574 out:
2575 	dout("try_write done on %p ret %d\n", con, ret);
2576 	return ret;
2577 }
2578 
2579 
2580 
2581 /*
2582  * Read what we can from the socket.
2583  */
2584 static int try_read(struct ceph_connection *con)
2585 {
2586 	int ret = -1;
2587 
2588 more:
2589 	dout("try_read start on %p state %lu\n", con, con->state);
2590 	if (con->state != CON_STATE_CONNECTING &&
2591 	    con->state != CON_STATE_NEGOTIATING &&
2592 	    con->state != CON_STATE_OPEN)
2593 		return 0;
2594 
2595 	BUG_ON(!con->sock);
2596 
2597 	dout("try_read tag %d in_base_pos %d\n", (int)con->in_tag,
2598 	     con->in_base_pos);
2599 
2600 	if (con->state == CON_STATE_CONNECTING) {
2601 		dout("try_read connecting\n");
2602 		ret = read_partial_banner(con);
2603 		if (ret <= 0)
2604 			goto out;
2605 		ret = process_banner(con);
2606 		if (ret < 0)
2607 			goto out;
2608 
2609 		con->state = CON_STATE_NEGOTIATING;
2610 
2611 		/*
2612 		 * Received banner is good, exchange connection info.
2613 		 * Do not reset out_kvec, as sending our banner raced
2614 		 * with receiving peer banner after connect completed.
2615 		 */
2616 		ret = prepare_write_connect(con);
2617 		if (ret < 0)
2618 			goto out;
2619 		prepare_read_connect(con);
2620 
2621 		/* Send connection info before awaiting response */
2622 		goto out;
2623 	}
2624 
2625 	if (con->state == CON_STATE_NEGOTIATING) {
2626 		dout("try_read negotiating\n");
2627 		ret = read_partial_connect(con);
2628 		if (ret <= 0)
2629 			goto out;
2630 		ret = process_connect(con);
2631 		if (ret < 0)
2632 			goto out;
2633 		goto more;
2634 	}
2635 
2636 	WARN_ON(con->state != CON_STATE_OPEN);
2637 
2638 	if (con->in_base_pos < 0) {
2639 		/*
2640 		 * skipping + discarding content.
2641 		 *
2642 		 * FIXME: there must be a better way to do this!
2643 		 */
2644 		static char buf[SKIP_BUF_SIZE];
2645 		int skip = min((int) sizeof (buf), -con->in_base_pos);
2646 
2647 		dout("skipping %d / %d bytes\n", skip, -con->in_base_pos);
2648 		ret = ceph_tcp_recvmsg(con->sock, buf, skip);
2649 		if (ret <= 0)
2650 			goto out;
2651 		con->in_base_pos += ret;
2652 		if (con->in_base_pos)
2653 			goto more;
2654 	}
2655 	if (con->in_tag == CEPH_MSGR_TAG_READY) {
2656 		/*
2657 		 * what's next?
2658 		 */
2659 		ret = ceph_tcp_recvmsg(con->sock, &con->in_tag, 1);
2660 		if (ret <= 0)
2661 			goto out;
2662 		dout("try_read got tag %d\n", (int)con->in_tag);
2663 		switch (con->in_tag) {
2664 		case CEPH_MSGR_TAG_MSG:
2665 			prepare_read_message(con);
2666 			break;
2667 		case CEPH_MSGR_TAG_ACK:
2668 			prepare_read_ack(con);
2669 			break;
2670 		case CEPH_MSGR_TAG_KEEPALIVE2_ACK:
2671 			prepare_read_keepalive_ack(con);
2672 			break;
2673 		case CEPH_MSGR_TAG_CLOSE:
2674 			con_close_socket(con);
2675 			con->state = CON_STATE_CLOSED;
2676 			goto out;
2677 		default:
2678 			goto bad_tag;
2679 		}
2680 	}
2681 	if (con->in_tag == CEPH_MSGR_TAG_MSG) {
2682 		ret = read_partial_message(con);
2683 		if (ret <= 0) {
2684 			switch (ret) {
2685 			case -EBADMSG:
2686 				con->error_msg = "bad crc/signature";
2687 				/* fall through */
2688 			case -EBADE:
2689 				ret = -EIO;
2690 				break;
2691 			case -EIO:
2692 				con->error_msg = "io error";
2693 				break;
2694 			}
2695 			goto out;
2696 		}
2697 		if (con->in_tag == CEPH_MSGR_TAG_READY)
2698 			goto more;
2699 		process_message(con);
2700 		if (con->state == CON_STATE_OPEN)
2701 			prepare_read_tag(con);
2702 		goto more;
2703 	}
2704 	if (con->in_tag == CEPH_MSGR_TAG_ACK ||
2705 	    con->in_tag == CEPH_MSGR_TAG_SEQ) {
2706 		/*
2707 		 * the final handshake seq exchange is semantically
2708 		 * equivalent to an ACK
2709 		 */
2710 		ret = read_partial_ack(con);
2711 		if (ret <= 0)
2712 			goto out;
2713 		process_ack(con);
2714 		goto more;
2715 	}
2716 	if (con->in_tag == CEPH_MSGR_TAG_KEEPALIVE2_ACK) {
2717 		ret = read_keepalive_ack(con);
2718 		if (ret <= 0)
2719 			goto out;
2720 		goto more;
2721 	}
2722 
2723 out:
2724 	dout("try_read done on %p ret %d\n", con, ret);
2725 	return ret;
2726 
2727 bad_tag:
2728 	pr_err("try_read bad con->in_tag = %d\n", (int)con->in_tag);
2729 	con->error_msg = "protocol error, garbage tag";
2730 	ret = -1;
2731 	goto out;
2732 }
2733 
2734 
2735 /*
2736  * Atomically queue work on a connection after the specified delay.
2737  * Bump @con reference to avoid races with connection teardown.
2738  * Returns 0 if work was queued, or an error code otherwise.
2739  */
2740 static int queue_con_delay(struct ceph_connection *con, unsigned long delay)
2741 {
2742 	if (!con->ops->get(con)) {
2743 		dout("%s %p ref count 0\n", __func__, con);
2744 		return -ENOENT;
2745 	}
2746 
2747 	if (!queue_delayed_work(ceph_msgr_wq, &con->work, delay)) {
2748 		dout("%s %p - already queued\n", __func__, con);
2749 		con->ops->put(con);
2750 		return -EBUSY;
2751 	}
2752 
2753 	dout("%s %p %lu\n", __func__, con, delay);
2754 	return 0;
2755 }
2756 
2757 static void queue_con(struct ceph_connection *con)
2758 {
2759 	(void) queue_con_delay(con, 0);
2760 }
2761 
2762 static void cancel_con(struct ceph_connection *con)
2763 {
2764 	if (cancel_delayed_work(&con->work)) {
2765 		dout("%s %p\n", __func__, con);
2766 		con->ops->put(con);
2767 	}
2768 }
2769 
2770 static bool con_sock_closed(struct ceph_connection *con)
2771 {
2772 	if (!con_flag_test_and_clear(con, CON_FLAG_SOCK_CLOSED))
2773 		return false;
2774 
2775 #define CASE(x)								\
2776 	case CON_STATE_ ## x:						\
2777 		con->error_msg = "socket closed (con state " #x ")";	\
2778 		break;
2779 
2780 	switch (con->state) {
2781 	CASE(CLOSED);
2782 	CASE(PREOPEN);
2783 	CASE(CONNECTING);
2784 	CASE(NEGOTIATING);
2785 	CASE(OPEN);
2786 	CASE(STANDBY);
2787 	default:
2788 		pr_warn("%s con %p unrecognized state %lu\n",
2789 			__func__, con, con->state);
2790 		con->error_msg = "unrecognized con state";
2791 		BUG();
2792 		break;
2793 	}
2794 #undef CASE
2795 
2796 	return true;
2797 }
2798 
2799 static bool con_backoff(struct ceph_connection *con)
2800 {
2801 	int ret;
2802 
2803 	if (!con_flag_test_and_clear(con, CON_FLAG_BACKOFF))
2804 		return false;
2805 
2806 	ret = queue_con_delay(con, round_jiffies_relative(con->delay));
2807 	if (ret) {
2808 		dout("%s: con %p FAILED to back off %lu\n", __func__,
2809 			con, con->delay);
2810 		BUG_ON(ret == -ENOENT);
2811 		con_flag_set(con, CON_FLAG_BACKOFF);
2812 	}
2813 
2814 	return true;
2815 }
2816 
2817 /* Finish fault handling; con->mutex must *not* be held here */
2818 
2819 static void con_fault_finish(struct ceph_connection *con)
2820 {
2821 	dout("%s %p\n", __func__, con);
2822 
2823 	/*
2824 	 * in case we faulted due to authentication, invalidate our
2825 	 * current tickets so that we can get new ones.
2826 	 */
2827 	if (con->auth_retry) {
2828 		dout("auth_retry %d, invalidating\n", con->auth_retry);
2829 		if (con->ops->invalidate_authorizer)
2830 			con->ops->invalidate_authorizer(con);
2831 		con->auth_retry = 0;
2832 	}
2833 
2834 	if (con->ops->fault)
2835 		con->ops->fault(con);
2836 }
2837 
2838 /*
2839  * Do some work on a connection.  Drop a connection ref when we're done.
2840  */
2841 static void ceph_con_workfn(struct work_struct *work)
2842 {
2843 	struct ceph_connection *con = container_of(work, struct ceph_connection,
2844 						   work.work);
2845 	bool fault;
2846 
2847 	mutex_lock(&con->mutex);
2848 	while (true) {
2849 		int ret;
2850 
2851 		if ((fault = con_sock_closed(con))) {
2852 			dout("%s: con %p SOCK_CLOSED\n", __func__, con);
2853 			break;
2854 		}
2855 		if (con_backoff(con)) {
2856 			dout("%s: con %p BACKOFF\n", __func__, con);
2857 			break;
2858 		}
2859 		if (con->state == CON_STATE_STANDBY) {
2860 			dout("%s: con %p STANDBY\n", __func__, con);
2861 			break;
2862 		}
2863 		if (con->state == CON_STATE_CLOSED) {
2864 			dout("%s: con %p CLOSED\n", __func__, con);
2865 			BUG_ON(con->sock);
2866 			break;
2867 		}
2868 		if (con->state == CON_STATE_PREOPEN) {
2869 			dout("%s: con %p PREOPEN\n", __func__, con);
2870 			BUG_ON(con->sock);
2871 		}
2872 
2873 		ret = try_read(con);
2874 		if (ret < 0) {
2875 			if (ret == -EAGAIN)
2876 				continue;
2877 			if (!con->error_msg)
2878 				con->error_msg = "socket error on read";
2879 			fault = true;
2880 			break;
2881 		}
2882 
2883 		ret = try_write(con);
2884 		if (ret < 0) {
2885 			if (ret == -EAGAIN)
2886 				continue;
2887 			if (!con->error_msg)
2888 				con->error_msg = "socket error on write";
2889 			fault = true;
2890 		}
2891 
2892 		break;	/* If we make it to here, we're done */
2893 	}
2894 	if (fault)
2895 		con_fault(con);
2896 	mutex_unlock(&con->mutex);
2897 
2898 	if (fault)
2899 		con_fault_finish(con);
2900 
2901 	con->ops->put(con);
2902 }
2903 
2904 /*
2905  * Generic error/fault handler.  A retry mechanism is used with
2906  * exponential backoff
2907  */
2908 static void con_fault(struct ceph_connection *con)
2909 {
2910 	dout("fault %p state %lu to peer %s\n",
2911 	     con, con->state, ceph_pr_addr(&con->peer_addr.in_addr));
2912 
2913 	pr_warn("%s%lld %s %s\n", ENTITY_NAME(con->peer_name),
2914 		ceph_pr_addr(&con->peer_addr.in_addr), con->error_msg);
2915 	con->error_msg = NULL;
2916 
2917 	WARN_ON(con->state != CON_STATE_CONNECTING &&
2918 	       con->state != CON_STATE_NEGOTIATING &&
2919 	       con->state != CON_STATE_OPEN);
2920 
2921 	con_close_socket(con);
2922 
2923 	if (con_flag_test(con, CON_FLAG_LOSSYTX)) {
2924 		dout("fault on LOSSYTX channel, marking CLOSED\n");
2925 		con->state = CON_STATE_CLOSED;
2926 		return;
2927 	}
2928 
2929 	if (con->in_msg) {
2930 		BUG_ON(con->in_msg->con != con);
2931 		ceph_msg_put(con->in_msg);
2932 		con->in_msg = NULL;
2933 	}
2934 
2935 	/* Requeue anything that hasn't been acked */
2936 	list_splice_init(&con->out_sent, &con->out_queue);
2937 
2938 	/* If there are no messages queued or keepalive pending, place
2939 	 * the connection in a STANDBY state */
2940 	if (list_empty(&con->out_queue) &&
2941 	    !con_flag_test(con, CON_FLAG_KEEPALIVE_PENDING)) {
2942 		dout("fault %p setting STANDBY clearing WRITE_PENDING\n", con);
2943 		con_flag_clear(con, CON_FLAG_WRITE_PENDING);
2944 		con->state = CON_STATE_STANDBY;
2945 	} else {
2946 		/* retry after a delay. */
2947 		con->state = CON_STATE_PREOPEN;
2948 		if (con->delay == 0)
2949 			con->delay = BASE_DELAY_INTERVAL;
2950 		else if (con->delay < MAX_DELAY_INTERVAL)
2951 			con->delay *= 2;
2952 		con_flag_set(con, CON_FLAG_BACKOFF);
2953 		queue_con(con);
2954 	}
2955 }
2956 
2957 
2958 
2959 /*
2960  * initialize a new messenger instance
2961  */
2962 void ceph_messenger_init(struct ceph_messenger *msgr,
2963 			 struct ceph_entity_addr *myaddr)
2964 {
2965 	spin_lock_init(&msgr->global_seq_lock);
2966 
2967 	if (myaddr)
2968 		msgr->inst.addr = *myaddr;
2969 
2970 	/* select a random nonce */
2971 	msgr->inst.addr.type = 0;
2972 	get_random_bytes(&msgr->inst.addr.nonce, sizeof(msgr->inst.addr.nonce));
2973 	encode_my_addr(msgr);
2974 
2975 	atomic_set(&msgr->stopping, 0);
2976 	write_pnet(&msgr->net, get_net(current->nsproxy->net_ns));
2977 
2978 	dout("%s %p\n", __func__, msgr);
2979 }
2980 EXPORT_SYMBOL(ceph_messenger_init);
2981 
2982 void ceph_messenger_fini(struct ceph_messenger *msgr)
2983 {
2984 	put_net(read_pnet(&msgr->net));
2985 }
2986 EXPORT_SYMBOL(ceph_messenger_fini);
2987 
2988 static void msg_con_set(struct ceph_msg *msg, struct ceph_connection *con)
2989 {
2990 	if (msg->con)
2991 		msg->con->ops->put(msg->con);
2992 
2993 	msg->con = con ? con->ops->get(con) : NULL;
2994 	BUG_ON(msg->con != con);
2995 }
2996 
2997 static void clear_standby(struct ceph_connection *con)
2998 {
2999 	/* come back from STANDBY? */
3000 	if (con->state == CON_STATE_STANDBY) {
3001 		dout("clear_standby %p and ++connect_seq\n", con);
3002 		con->state = CON_STATE_PREOPEN;
3003 		con->connect_seq++;
3004 		WARN_ON(con_flag_test(con, CON_FLAG_WRITE_PENDING));
3005 		WARN_ON(con_flag_test(con, CON_FLAG_KEEPALIVE_PENDING));
3006 	}
3007 }
3008 
3009 /*
3010  * Queue up an outgoing message on the given connection.
3011  */
3012 void ceph_con_send(struct ceph_connection *con, struct ceph_msg *msg)
3013 {
3014 	/* set src+dst */
3015 	msg->hdr.src = con->msgr->inst.name;
3016 	BUG_ON(msg->front.iov_len != le32_to_cpu(msg->hdr.front_len));
3017 	msg->needs_out_seq = true;
3018 
3019 	mutex_lock(&con->mutex);
3020 
3021 	if (con->state == CON_STATE_CLOSED) {
3022 		dout("con_send %p closed, dropping %p\n", con, msg);
3023 		ceph_msg_put(msg);
3024 		mutex_unlock(&con->mutex);
3025 		return;
3026 	}
3027 
3028 	msg_con_set(msg, con);
3029 
3030 	BUG_ON(!list_empty(&msg->list_head));
3031 	list_add_tail(&msg->list_head, &con->out_queue);
3032 	dout("----- %p to %s%lld %d=%s len %d+%d+%d -----\n", msg,
3033 	     ENTITY_NAME(con->peer_name), le16_to_cpu(msg->hdr.type),
3034 	     ceph_msg_type_name(le16_to_cpu(msg->hdr.type)),
3035 	     le32_to_cpu(msg->hdr.front_len),
3036 	     le32_to_cpu(msg->hdr.middle_len),
3037 	     le32_to_cpu(msg->hdr.data_len));
3038 
3039 	clear_standby(con);
3040 	mutex_unlock(&con->mutex);
3041 
3042 	/* if there wasn't anything waiting to send before, queue
3043 	 * new work */
3044 	if (con_flag_test_and_set(con, CON_FLAG_WRITE_PENDING) == 0)
3045 		queue_con(con);
3046 }
3047 EXPORT_SYMBOL(ceph_con_send);
3048 
3049 /*
3050  * Revoke a message that was previously queued for send
3051  */
3052 void ceph_msg_revoke(struct ceph_msg *msg)
3053 {
3054 	struct ceph_connection *con = msg->con;
3055 
3056 	if (!con) {
3057 		dout("%s msg %p null con\n", __func__, msg);
3058 		return;		/* Message not in our possession */
3059 	}
3060 
3061 	mutex_lock(&con->mutex);
3062 	if (!list_empty(&msg->list_head)) {
3063 		dout("%s %p msg %p - was on queue\n", __func__, con, msg);
3064 		list_del_init(&msg->list_head);
3065 		msg->hdr.seq = 0;
3066 
3067 		ceph_msg_put(msg);
3068 	}
3069 	if (con->out_msg == msg) {
3070 		BUG_ON(con->out_skip);
3071 		/* footer */
3072 		if (con->out_msg_done) {
3073 			con->out_skip += con_out_kvec_skip(con);
3074 		} else {
3075 			BUG_ON(!msg->data_length);
3076 			con->out_skip += sizeof_footer(con);
3077 		}
3078 		/* data, middle, front */
3079 		if (msg->data_length)
3080 			con->out_skip += msg->cursor.total_resid;
3081 		if (msg->middle)
3082 			con->out_skip += con_out_kvec_skip(con);
3083 		con->out_skip += con_out_kvec_skip(con);
3084 
3085 		dout("%s %p msg %p - was sending, will write %d skip %d\n",
3086 		     __func__, con, msg, con->out_kvec_bytes, con->out_skip);
3087 		msg->hdr.seq = 0;
3088 		con->out_msg = NULL;
3089 		ceph_msg_put(msg);
3090 	}
3091 
3092 	mutex_unlock(&con->mutex);
3093 }
3094 
3095 /*
3096  * Revoke a message that we may be reading data into
3097  */
3098 void ceph_msg_revoke_incoming(struct ceph_msg *msg)
3099 {
3100 	struct ceph_connection *con = msg->con;
3101 
3102 	if (!con) {
3103 		dout("%s msg %p null con\n", __func__, msg);
3104 		return;		/* Message not in our possession */
3105 	}
3106 
3107 	mutex_lock(&con->mutex);
3108 	if (con->in_msg == msg) {
3109 		unsigned int front_len = le32_to_cpu(con->in_hdr.front_len);
3110 		unsigned int middle_len = le32_to_cpu(con->in_hdr.middle_len);
3111 		unsigned int data_len = le32_to_cpu(con->in_hdr.data_len);
3112 
3113 		/* skip rest of message */
3114 		dout("%s %p msg %p revoked\n", __func__, con, msg);
3115 		con->in_base_pos = con->in_base_pos -
3116 				sizeof(struct ceph_msg_header) -
3117 				front_len -
3118 				middle_len -
3119 				data_len -
3120 				sizeof(struct ceph_msg_footer);
3121 		ceph_msg_put(con->in_msg);
3122 		con->in_msg = NULL;
3123 		con->in_tag = CEPH_MSGR_TAG_READY;
3124 		con->in_seq++;
3125 	} else {
3126 		dout("%s %p in_msg %p msg %p no-op\n",
3127 		     __func__, con, con->in_msg, msg);
3128 	}
3129 	mutex_unlock(&con->mutex);
3130 }
3131 
3132 /*
3133  * Queue a keepalive byte to ensure the tcp connection is alive.
3134  */
3135 void ceph_con_keepalive(struct ceph_connection *con)
3136 {
3137 	dout("con_keepalive %p\n", con);
3138 	mutex_lock(&con->mutex);
3139 	clear_standby(con);
3140 	mutex_unlock(&con->mutex);
3141 	if (con_flag_test_and_set(con, CON_FLAG_KEEPALIVE_PENDING) == 0 &&
3142 	    con_flag_test_and_set(con, CON_FLAG_WRITE_PENDING) == 0)
3143 		queue_con(con);
3144 }
3145 EXPORT_SYMBOL(ceph_con_keepalive);
3146 
3147 bool ceph_con_keepalive_expired(struct ceph_connection *con,
3148 			       unsigned long interval)
3149 {
3150 	if (interval > 0 &&
3151 	    (con->peer_features & CEPH_FEATURE_MSGR_KEEPALIVE2)) {
3152 		struct timespec now = CURRENT_TIME;
3153 		struct timespec ts;
3154 		jiffies_to_timespec(interval, &ts);
3155 		ts = timespec_add(con->last_keepalive_ack, ts);
3156 		return timespec_compare(&now, &ts) >= 0;
3157 	}
3158 	return false;
3159 }
3160 
3161 static struct ceph_msg_data *ceph_msg_data_create(enum ceph_msg_data_type type)
3162 {
3163 	struct ceph_msg_data *data;
3164 
3165 	if (WARN_ON(!ceph_msg_data_type_valid(type)))
3166 		return NULL;
3167 
3168 	data = kmem_cache_zalloc(ceph_msg_data_cache, GFP_NOFS);
3169 	if (data)
3170 		data->type = type;
3171 	INIT_LIST_HEAD(&data->links);
3172 
3173 	return data;
3174 }
3175 
3176 static void ceph_msg_data_destroy(struct ceph_msg_data *data)
3177 {
3178 	if (!data)
3179 		return;
3180 
3181 	WARN_ON(!list_empty(&data->links));
3182 	if (data->type == CEPH_MSG_DATA_PAGELIST)
3183 		ceph_pagelist_release(data->pagelist);
3184 	kmem_cache_free(ceph_msg_data_cache, data);
3185 }
3186 
3187 void ceph_msg_data_add_pages(struct ceph_msg *msg, struct page **pages,
3188 		size_t length, size_t alignment)
3189 {
3190 	struct ceph_msg_data *data;
3191 
3192 	BUG_ON(!pages);
3193 	BUG_ON(!length);
3194 
3195 	data = ceph_msg_data_create(CEPH_MSG_DATA_PAGES);
3196 	BUG_ON(!data);
3197 	data->pages = pages;
3198 	data->length = length;
3199 	data->alignment = alignment & ~PAGE_MASK;
3200 
3201 	list_add_tail(&data->links, &msg->data);
3202 	msg->data_length += length;
3203 }
3204 EXPORT_SYMBOL(ceph_msg_data_add_pages);
3205 
3206 void ceph_msg_data_add_pagelist(struct ceph_msg *msg,
3207 				struct ceph_pagelist *pagelist)
3208 {
3209 	struct ceph_msg_data *data;
3210 
3211 	BUG_ON(!pagelist);
3212 	BUG_ON(!pagelist->length);
3213 
3214 	data = ceph_msg_data_create(CEPH_MSG_DATA_PAGELIST);
3215 	BUG_ON(!data);
3216 	data->pagelist = pagelist;
3217 
3218 	list_add_tail(&data->links, &msg->data);
3219 	msg->data_length += pagelist->length;
3220 }
3221 EXPORT_SYMBOL(ceph_msg_data_add_pagelist);
3222 
3223 #ifdef	CONFIG_BLOCK
3224 void ceph_msg_data_add_bio(struct ceph_msg *msg, struct bio *bio,
3225 		size_t length)
3226 {
3227 	struct ceph_msg_data *data;
3228 
3229 	BUG_ON(!bio);
3230 
3231 	data = ceph_msg_data_create(CEPH_MSG_DATA_BIO);
3232 	BUG_ON(!data);
3233 	data->bio = bio;
3234 	data->bio_length = length;
3235 
3236 	list_add_tail(&data->links, &msg->data);
3237 	msg->data_length += length;
3238 }
3239 EXPORT_SYMBOL(ceph_msg_data_add_bio);
3240 #endif	/* CONFIG_BLOCK */
3241 
3242 /*
3243  * construct a new message with given type, size
3244  * the new msg has a ref count of 1.
3245  */
3246 struct ceph_msg *ceph_msg_new(int type, int front_len, gfp_t flags,
3247 			      bool can_fail)
3248 {
3249 	struct ceph_msg *m;
3250 
3251 	m = kmem_cache_zalloc(ceph_msg_cache, flags);
3252 	if (m == NULL)
3253 		goto out;
3254 
3255 	m->hdr.type = cpu_to_le16(type);
3256 	m->hdr.priority = cpu_to_le16(CEPH_MSG_PRIO_DEFAULT);
3257 	m->hdr.front_len = cpu_to_le32(front_len);
3258 
3259 	INIT_LIST_HEAD(&m->list_head);
3260 	kref_init(&m->kref);
3261 	INIT_LIST_HEAD(&m->data);
3262 
3263 	/* front */
3264 	if (front_len) {
3265 		m->front.iov_base = ceph_kvmalloc(front_len, flags);
3266 		if (m->front.iov_base == NULL) {
3267 			dout("ceph_msg_new can't allocate %d bytes\n",
3268 			     front_len);
3269 			goto out2;
3270 		}
3271 	} else {
3272 		m->front.iov_base = NULL;
3273 	}
3274 	m->front_alloc_len = m->front.iov_len = front_len;
3275 
3276 	dout("ceph_msg_new %p front %d\n", m, front_len);
3277 	return m;
3278 
3279 out2:
3280 	ceph_msg_put(m);
3281 out:
3282 	if (!can_fail) {
3283 		pr_err("msg_new can't create type %d front %d\n", type,
3284 		       front_len);
3285 		WARN_ON(1);
3286 	} else {
3287 		dout("msg_new can't create type %d front %d\n", type,
3288 		     front_len);
3289 	}
3290 	return NULL;
3291 }
3292 EXPORT_SYMBOL(ceph_msg_new);
3293 
3294 /*
3295  * Allocate "middle" portion of a message, if it is needed and wasn't
3296  * allocated by alloc_msg.  This allows us to read a small fixed-size
3297  * per-type header in the front and then gracefully fail (i.e.,
3298  * propagate the error to the caller based on info in the front) when
3299  * the middle is too large.
3300  */
3301 static int ceph_alloc_middle(struct ceph_connection *con, struct ceph_msg *msg)
3302 {
3303 	int type = le16_to_cpu(msg->hdr.type);
3304 	int middle_len = le32_to_cpu(msg->hdr.middle_len);
3305 
3306 	dout("alloc_middle %p type %d %s middle_len %d\n", msg, type,
3307 	     ceph_msg_type_name(type), middle_len);
3308 	BUG_ON(!middle_len);
3309 	BUG_ON(msg->middle);
3310 
3311 	msg->middle = ceph_buffer_new(middle_len, GFP_NOFS);
3312 	if (!msg->middle)
3313 		return -ENOMEM;
3314 	return 0;
3315 }
3316 
3317 /*
3318  * Allocate a message for receiving an incoming message on a
3319  * connection, and save the result in con->in_msg.  Uses the
3320  * connection's private alloc_msg op if available.
3321  *
3322  * Returns 0 on success, or a negative error code.
3323  *
3324  * On success, if we set *skip = 1:
3325  *  - the next message should be skipped and ignored.
3326  *  - con->in_msg == NULL
3327  * or if we set *skip = 0:
3328  *  - con->in_msg is non-null.
3329  * On error (ENOMEM, EAGAIN, ...),
3330  *  - con->in_msg == NULL
3331  */
3332 static int ceph_con_in_msg_alloc(struct ceph_connection *con, int *skip)
3333 {
3334 	struct ceph_msg_header *hdr = &con->in_hdr;
3335 	int middle_len = le32_to_cpu(hdr->middle_len);
3336 	struct ceph_msg *msg;
3337 	int ret = 0;
3338 
3339 	BUG_ON(con->in_msg != NULL);
3340 	BUG_ON(!con->ops->alloc_msg);
3341 
3342 	mutex_unlock(&con->mutex);
3343 	msg = con->ops->alloc_msg(con, hdr, skip);
3344 	mutex_lock(&con->mutex);
3345 	if (con->state != CON_STATE_OPEN) {
3346 		if (msg)
3347 			ceph_msg_put(msg);
3348 		return -EAGAIN;
3349 	}
3350 	if (msg) {
3351 		BUG_ON(*skip);
3352 		msg_con_set(msg, con);
3353 		con->in_msg = msg;
3354 	} else {
3355 		/*
3356 		 * Null message pointer means either we should skip
3357 		 * this message or we couldn't allocate memory.  The
3358 		 * former is not an error.
3359 		 */
3360 		if (*skip)
3361 			return 0;
3362 
3363 		con->error_msg = "error allocating memory for incoming message";
3364 		return -ENOMEM;
3365 	}
3366 	memcpy(&con->in_msg->hdr, &con->in_hdr, sizeof(con->in_hdr));
3367 
3368 	if (middle_len && !con->in_msg->middle) {
3369 		ret = ceph_alloc_middle(con, con->in_msg);
3370 		if (ret < 0) {
3371 			ceph_msg_put(con->in_msg);
3372 			con->in_msg = NULL;
3373 		}
3374 	}
3375 
3376 	return ret;
3377 }
3378 
3379 
3380 /*
3381  * Free a generically kmalloc'd message.
3382  */
3383 static void ceph_msg_free(struct ceph_msg *m)
3384 {
3385 	dout("%s %p\n", __func__, m);
3386 	kvfree(m->front.iov_base);
3387 	kmem_cache_free(ceph_msg_cache, m);
3388 }
3389 
3390 static void ceph_msg_release(struct kref *kref)
3391 {
3392 	struct ceph_msg *m = container_of(kref, struct ceph_msg, kref);
3393 	struct ceph_msg_data *data, *next;
3394 
3395 	dout("%s %p\n", __func__, m);
3396 	WARN_ON(!list_empty(&m->list_head));
3397 
3398 	msg_con_set(m, NULL);
3399 
3400 	/* drop middle, data, if any */
3401 	if (m->middle) {
3402 		ceph_buffer_put(m->middle);
3403 		m->middle = NULL;
3404 	}
3405 
3406 	list_for_each_entry_safe(data, next, &m->data, links) {
3407 		list_del_init(&data->links);
3408 		ceph_msg_data_destroy(data);
3409 	}
3410 	m->data_length = 0;
3411 
3412 	if (m->pool)
3413 		ceph_msgpool_put(m->pool, m);
3414 	else
3415 		ceph_msg_free(m);
3416 }
3417 
3418 struct ceph_msg *ceph_msg_get(struct ceph_msg *msg)
3419 {
3420 	dout("%s %p (was %d)\n", __func__, msg,
3421 	     atomic_read(&msg->kref.refcount));
3422 	kref_get(&msg->kref);
3423 	return msg;
3424 }
3425 EXPORT_SYMBOL(ceph_msg_get);
3426 
3427 void ceph_msg_put(struct ceph_msg *msg)
3428 {
3429 	dout("%s %p (was %d)\n", __func__, msg,
3430 	     atomic_read(&msg->kref.refcount));
3431 	kref_put(&msg->kref, ceph_msg_release);
3432 }
3433 EXPORT_SYMBOL(ceph_msg_put);
3434 
3435 void ceph_msg_dump(struct ceph_msg *msg)
3436 {
3437 	pr_debug("msg_dump %p (front_alloc_len %d length %zd)\n", msg,
3438 		 msg->front_alloc_len, msg->data_length);
3439 	print_hex_dump(KERN_DEBUG, "header: ",
3440 		       DUMP_PREFIX_OFFSET, 16, 1,
3441 		       &msg->hdr, sizeof(msg->hdr), true);
3442 	print_hex_dump(KERN_DEBUG, " front: ",
3443 		       DUMP_PREFIX_OFFSET, 16, 1,
3444 		       msg->front.iov_base, msg->front.iov_len, true);
3445 	if (msg->middle)
3446 		print_hex_dump(KERN_DEBUG, "middle: ",
3447 			       DUMP_PREFIX_OFFSET, 16, 1,
3448 			       msg->middle->vec.iov_base,
3449 			       msg->middle->vec.iov_len, true);
3450 	print_hex_dump(KERN_DEBUG, "footer: ",
3451 		       DUMP_PREFIX_OFFSET, 16, 1,
3452 		       &msg->footer, sizeof(msg->footer), true);
3453 }
3454 EXPORT_SYMBOL(ceph_msg_dump);
3455