xref: /linux/net/rds/recv.c (revision 60e13231561b3a4c5269bfa1ef6c0569ad6f28ec)
1 /*
2  * Copyright (c) 2006 Oracle.  All rights reserved.
3  *
4  * This software is available to you under a choice of one of two
5  * licenses.  You may choose to be licensed under the terms of the GNU
6  * General Public License (GPL) Version 2, available from the file
7  * COPYING in the main directory of this source tree, or the
8  * OpenIB.org BSD license below:
9  *
10  *     Redistribution and use in source and binary forms, with or
11  *     without modification, are permitted provided that the following
12  *     conditions are met:
13  *
14  *      - Redistributions of source code must retain the above
15  *        copyright notice, this list of conditions and the following
16  *        disclaimer.
17  *
18  *      - Redistributions in binary form must reproduce the above
19  *        copyright notice, this list of conditions and the following
20  *        disclaimer in the documentation and/or other materials
21  *        provided with the distribution.
22  *
23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30  * SOFTWARE.
31  *
32  */
33 #include <linux/kernel.h>
34 #include <linux/slab.h>
35 #include <net/sock.h>
36 #include <linux/in.h>
37 
38 #include "rds.h"
39 
40 void rds_inc_init(struct rds_incoming *inc, struct rds_connection *conn,
41 		  __be32 saddr)
42 {
43 	atomic_set(&inc->i_refcount, 1);
44 	INIT_LIST_HEAD(&inc->i_item);
45 	inc->i_conn = conn;
46 	inc->i_saddr = saddr;
47 	inc->i_rdma_cookie = 0;
48 }
49 EXPORT_SYMBOL_GPL(rds_inc_init);
50 
51 static void rds_inc_addref(struct rds_incoming *inc)
52 {
53 	rdsdebug("addref inc %p ref %d\n", inc, atomic_read(&inc->i_refcount));
54 	atomic_inc(&inc->i_refcount);
55 }
56 
57 void rds_inc_put(struct rds_incoming *inc)
58 {
59 	rdsdebug("put inc %p ref %d\n", inc, atomic_read(&inc->i_refcount));
60 	if (atomic_dec_and_test(&inc->i_refcount)) {
61 		BUG_ON(!list_empty(&inc->i_item));
62 
63 		inc->i_conn->c_trans->inc_free(inc);
64 	}
65 }
66 EXPORT_SYMBOL_GPL(rds_inc_put);
67 
68 static void rds_recv_rcvbuf_delta(struct rds_sock *rs, struct sock *sk,
69 				  struct rds_cong_map *map,
70 				  int delta, __be16 port)
71 {
72 	int now_congested;
73 
74 	if (delta == 0)
75 		return;
76 
77 	rs->rs_rcv_bytes += delta;
78 	now_congested = rs->rs_rcv_bytes > rds_sk_rcvbuf(rs);
79 
80 	rdsdebug("rs %p (%pI4:%u) recv bytes %d buf %d "
81 	  "now_cong %d delta %d\n",
82 	  rs, &rs->rs_bound_addr,
83 	  ntohs(rs->rs_bound_port), rs->rs_rcv_bytes,
84 	  rds_sk_rcvbuf(rs), now_congested, delta);
85 
86 	/* wasn't -> am congested */
87 	if (!rs->rs_congested && now_congested) {
88 		rs->rs_congested = 1;
89 		rds_cong_set_bit(map, port);
90 		rds_cong_queue_updates(map);
91 	}
92 	/* was -> aren't congested */
93 	/* Require more free space before reporting uncongested to prevent
94 	   bouncing cong/uncong state too often */
95 	else if (rs->rs_congested && (rs->rs_rcv_bytes < (rds_sk_rcvbuf(rs)/2))) {
96 		rs->rs_congested = 0;
97 		rds_cong_clear_bit(map, port);
98 		rds_cong_queue_updates(map);
99 	}
100 
101 	/* do nothing if no change in cong state */
102 }
103 
104 /*
105  * Process all extension headers that come with this message.
106  */
107 static void rds_recv_incoming_exthdrs(struct rds_incoming *inc, struct rds_sock *rs)
108 {
109 	struct rds_header *hdr = &inc->i_hdr;
110 	unsigned int pos = 0, type, len;
111 	union {
112 		struct rds_ext_header_version version;
113 		struct rds_ext_header_rdma rdma;
114 		struct rds_ext_header_rdma_dest rdma_dest;
115 	} buffer;
116 
117 	while (1) {
118 		len = sizeof(buffer);
119 		type = rds_message_next_extension(hdr, &pos, &buffer, &len);
120 		if (type == RDS_EXTHDR_NONE)
121 			break;
122 		/* Process extension header here */
123 		switch (type) {
124 		case RDS_EXTHDR_RDMA:
125 			rds_rdma_unuse(rs, be32_to_cpu(buffer.rdma.h_rdma_rkey), 0);
126 			break;
127 
128 		case RDS_EXTHDR_RDMA_DEST:
129 			/* We ignore the size for now. We could stash it
130 			 * somewhere and use it for error checking. */
131 			inc->i_rdma_cookie = rds_rdma_make_cookie(
132 					be32_to_cpu(buffer.rdma_dest.h_rdma_rkey),
133 					be32_to_cpu(buffer.rdma_dest.h_rdma_offset));
134 
135 			break;
136 		}
137 	}
138 }
139 
140 /*
141  * The transport must make sure that this is serialized against other
142  * rx and conn reset on this specific conn.
143  *
144  * We currently assert that only one fragmented message will be sent
145  * down a connection at a time.  This lets us reassemble in the conn
146  * instead of per-flow which means that we don't have to go digging through
147  * flows to tear down partial reassembly progress on conn failure and
148  * we save flow lookup and locking for each frag arrival.  It does mean
149  * that small messages will wait behind large ones.  Fragmenting at all
150  * is only to reduce the memory consumption of pre-posted buffers.
151  *
152  * The caller passes in saddr and daddr instead of us getting it from the
153  * conn.  This lets loopback, who only has one conn for both directions,
154  * tell us which roles the addrs in the conn are playing for this message.
155  */
156 void rds_recv_incoming(struct rds_connection *conn, __be32 saddr, __be32 daddr,
157 		       struct rds_incoming *inc, gfp_t gfp, enum km_type km)
158 {
159 	struct rds_sock *rs = NULL;
160 	struct sock *sk;
161 	unsigned long flags;
162 
163 	inc->i_conn = conn;
164 	inc->i_rx_jiffies = jiffies;
165 
166 	rdsdebug("conn %p next %llu inc %p seq %llu len %u sport %u dport %u "
167 		 "flags 0x%x rx_jiffies %lu\n", conn,
168 		 (unsigned long long)conn->c_next_rx_seq,
169 		 inc,
170 		 (unsigned long long)be64_to_cpu(inc->i_hdr.h_sequence),
171 		 be32_to_cpu(inc->i_hdr.h_len),
172 		 be16_to_cpu(inc->i_hdr.h_sport),
173 		 be16_to_cpu(inc->i_hdr.h_dport),
174 		 inc->i_hdr.h_flags,
175 		 inc->i_rx_jiffies);
176 
177 	/*
178 	 * Sequence numbers should only increase.  Messages get their
179 	 * sequence number as they're queued in a sending conn.  They
180 	 * can be dropped, though, if the sending socket is closed before
181 	 * they hit the wire.  So sequence numbers can skip forward
182 	 * under normal operation.  They can also drop back in the conn
183 	 * failover case as previously sent messages are resent down the
184 	 * new instance of a conn.  We drop those, otherwise we have
185 	 * to assume that the next valid seq does not come after a
186 	 * hole in the fragment stream.
187 	 *
188 	 * The headers don't give us a way to realize if fragments of
189 	 * a message have been dropped.  We assume that frags that arrive
190 	 * to a flow are part of the current message on the flow that is
191 	 * being reassembled.  This means that senders can't drop messages
192 	 * from the sending conn until all their frags are sent.
193 	 *
194 	 * XXX we could spend more on the wire to get more robust failure
195 	 * detection, arguably worth it to avoid data corruption.
196 	 */
197 	if (be64_to_cpu(inc->i_hdr.h_sequence) < conn->c_next_rx_seq &&
198 	    (inc->i_hdr.h_flags & RDS_FLAG_RETRANSMITTED)) {
199 		rds_stats_inc(s_recv_drop_old_seq);
200 		goto out;
201 	}
202 	conn->c_next_rx_seq = be64_to_cpu(inc->i_hdr.h_sequence) + 1;
203 
204 	if (rds_sysctl_ping_enable && inc->i_hdr.h_dport == 0) {
205 		rds_stats_inc(s_recv_ping);
206 		rds_send_pong(conn, inc->i_hdr.h_sport);
207 		goto out;
208 	}
209 
210 	rs = rds_find_bound(daddr, inc->i_hdr.h_dport);
211 	if (!rs) {
212 		rds_stats_inc(s_recv_drop_no_sock);
213 		goto out;
214 	}
215 
216 	/* Process extension headers */
217 	rds_recv_incoming_exthdrs(inc, rs);
218 
219 	/* We can be racing with rds_release() which marks the socket dead. */
220 	sk = rds_rs_to_sk(rs);
221 
222 	/* serialize with rds_release -> sock_orphan */
223 	write_lock_irqsave(&rs->rs_recv_lock, flags);
224 	if (!sock_flag(sk, SOCK_DEAD)) {
225 		rdsdebug("adding inc %p to rs %p's recv queue\n", inc, rs);
226 		rds_stats_inc(s_recv_queued);
227 		rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
228 				      be32_to_cpu(inc->i_hdr.h_len),
229 				      inc->i_hdr.h_dport);
230 		rds_inc_addref(inc);
231 		list_add_tail(&inc->i_item, &rs->rs_recv_queue);
232 		__rds_wake_sk_sleep(sk);
233 	} else {
234 		rds_stats_inc(s_recv_drop_dead_sock);
235 	}
236 	write_unlock_irqrestore(&rs->rs_recv_lock, flags);
237 
238 out:
239 	if (rs)
240 		rds_sock_put(rs);
241 }
242 EXPORT_SYMBOL_GPL(rds_recv_incoming);
243 
244 /*
245  * be very careful here.  This is being called as the condition in
246  * wait_event_*() needs to cope with being called many times.
247  */
248 static int rds_next_incoming(struct rds_sock *rs, struct rds_incoming **inc)
249 {
250 	unsigned long flags;
251 
252 	if (!*inc) {
253 		read_lock_irqsave(&rs->rs_recv_lock, flags);
254 		if (!list_empty(&rs->rs_recv_queue)) {
255 			*inc = list_entry(rs->rs_recv_queue.next,
256 					  struct rds_incoming,
257 					  i_item);
258 			rds_inc_addref(*inc);
259 		}
260 		read_unlock_irqrestore(&rs->rs_recv_lock, flags);
261 	}
262 
263 	return *inc != NULL;
264 }
265 
266 static int rds_still_queued(struct rds_sock *rs, struct rds_incoming *inc,
267 			    int drop)
268 {
269 	struct sock *sk = rds_rs_to_sk(rs);
270 	int ret = 0;
271 	unsigned long flags;
272 
273 	write_lock_irqsave(&rs->rs_recv_lock, flags);
274 	if (!list_empty(&inc->i_item)) {
275 		ret = 1;
276 		if (drop) {
277 			/* XXX make sure this i_conn is reliable */
278 			rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
279 					      -be32_to_cpu(inc->i_hdr.h_len),
280 					      inc->i_hdr.h_dport);
281 			list_del_init(&inc->i_item);
282 			rds_inc_put(inc);
283 		}
284 	}
285 	write_unlock_irqrestore(&rs->rs_recv_lock, flags);
286 
287 	rdsdebug("inc %p rs %p still %d dropped %d\n", inc, rs, ret, drop);
288 	return ret;
289 }
290 
291 /*
292  * Pull errors off the error queue.
293  * If msghdr is NULL, we will just purge the error queue.
294  */
295 int rds_notify_queue_get(struct rds_sock *rs, struct msghdr *msghdr)
296 {
297 	struct rds_notifier *notifier;
298 	struct rds_rdma_notify cmsg = { 0 }; /* fill holes with zero */
299 	unsigned int count = 0, max_messages = ~0U;
300 	unsigned long flags;
301 	LIST_HEAD(copy);
302 	int err = 0;
303 
304 
305 	/* put_cmsg copies to user space and thus may sleep. We can't do this
306 	 * with rs_lock held, so first grab as many notifications as we can stuff
307 	 * in the user provided cmsg buffer. We don't try to copy more, to avoid
308 	 * losing notifications - except when the buffer is so small that it wouldn't
309 	 * even hold a single notification. Then we give him as much of this single
310 	 * msg as we can squeeze in, and set MSG_CTRUNC.
311 	 */
312 	if (msghdr) {
313 		max_messages = msghdr->msg_controllen / CMSG_SPACE(sizeof(cmsg));
314 		if (!max_messages)
315 			max_messages = 1;
316 	}
317 
318 	spin_lock_irqsave(&rs->rs_lock, flags);
319 	while (!list_empty(&rs->rs_notify_queue) && count < max_messages) {
320 		notifier = list_entry(rs->rs_notify_queue.next,
321 				struct rds_notifier, n_list);
322 		list_move(&notifier->n_list, &copy);
323 		count++;
324 	}
325 	spin_unlock_irqrestore(&rs->rs_lock, flags);
326 
327 	if (!count)
328 		return 0;
329 
330 	while (!list_empty(&copy)) {
331 		notifier = list_entry(copy.next, struct rds_notifier, n_list);
332 
333 		if (msghdr) {
334 			cmsg.user_token = notifier->n_user_token;
335 			cmsg.status = notifier->n_status;
336 
337 			err = put_cmsg(msghdr, SOL_RDS, RDS_CMSG_RDMA_STATUS,
338 				       sizeof(cmsg), &cmsg);
339 			if (err)
340 				break;
341 		}
342 
343 		list_del_init(&notifier->n_list);
344 		kfree(notifier);
345 	}
346 
347 	/* If we bailed out because of an error in put_cmsg,
348 	 * we may be left with one or more notifications that we
349 	 * didn't process. Return them to the head of the list. */
350 	if (!list_empty(&copy)) {
351 		spin_lock_irqsave(&rs->rs_lock, flags);
352 		list_splice(&copy, &rs->rs_notify_queue);
353 		spin_unlock_irqrestore(&rs->rs_lock, flags);
354 	}
355 
356 	return err;
357 }
358 
359 /*
360  * Queue a congestion notification
361  */
362 static int rds_notify_cong(struct rds_sock *rs, struct msghdr *msghdr)
363 {
364 	uint64_t notify = rs->rs_cong_notify;
365 	unsigned long flags;
366 	int err;
367 
368 	err = put_cmsg(msghdr, SOL_RDS, RDS_CMSG_CONG_UPDATE,
369 			sizeof(notify), &notify);
370 	if (err)
371 		return err;
372 
373 	spin_lock_irqsave(&rs->rs_lock, flags);
374 	rs->rs_cong_notify &= ~notify;
375 	spin_unlock_irqrestore(&rs->rs_lock, flags);
376 
377 	return 0;
378 }
379 
380 /*
381  * Receive any control messages.
382  */
383 static int rds_cmsg_recv(struct rds_incoming *inc, struct msghdr *msg)
384 {
385 	int ret = 0;
386 
387 	if (inc->i_rdma_cookie) {
388 		ret = put_cmsg(msg, SOL_RDS, RDS_CMSG_RDMA_DEST,
389 				sizeof(inc->i_rdma_cookie), &inc->i_rdma_cookie);
390 		if (ret)
391 			return ret;
392 	}
393 
394 	return 0;
395 }
396 
397 int rds_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
398 		size_t size, int msg_flags)
399 {
400 	struct sock *sk = sock->sk;
401 	struct rds_sock *rs = rds_sk_to_rs(sk);
402 	long timeo;
403 	int ret = 0, nonblock = msg_flags & MSG_DONTWAIT;
404 	struct sockaddr_in *sin;
405 	struct rds_incoming *inc = NULL;
406 
407 	/* udp_recvmsg()->sock_recvtimeo() gets away without locking too.. */
408 	timeo = sock_rcvtimeo(sk, nonblock);
409 
410 	rdsdebug("size %zu flags 0x%x timeo %ld\n", size, msg_flags, timeo);
411 
412 	if (msg_flags & MSG_OOB)
413 		goto out;
414 
415 	while (1) {
416 		/* If there are pending notifications, do those - and nothing else */
417 		if (!list_empty(&rs->rs_notify_queue)) {
418 			ret = rds_notify_queue_get(rs, msg);
419 			break;
420 		}
421 
422 		if (rs->rs_cong_notify) {
423 			ret = rds_notify_cong(rs, msg);
424 			break;
425 		}
426 
427 		if (!rds_next_incoming(rs, &inc)) {
428 			if (nonblock) {
429 				ret = -EAGAIN;
430 				break;
431 			}
432 
433 			timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
434 					(!list_empty(&rs->rs_notify_queue) ||
435 					 rs->rs_cong_notify ||
436 					 rds_next_incoming(rs, &inc)), timeo);
437 			rdsdebug("recvmsg woke inc %p timeo %ld\n", inc,
438 				 timeo);
439 			if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
440 				continue;
441 
442 			ret = timeo;
443 			if (ret == 0)
444 				ret = -ETIMEDOUT;
445 			break;
446 		}
447 
448 		rdsdebug("copying inc %p from %pI4:%u to user\n", inc,
449 			 &inc->i_conn->c_faddr,
450 			 ntohs(inc->i_hdr.h_sport));
451 		ret = inc->i_conn->c_trans->inc_copy_to_user(inc, msg->msg_iov,
452 							     size);
453 		if (ret < 0)
454 			break;
455 
456 		/*
457 		 * if the message we just copied isn't at the head of the
458 		 * recv queue then someone else raced us to return it, try
459 		 * to get the next message.
460 		 */
461 		if (!rds_still_queued(rs, inc, !(msg_flags & MSG_PEEK))) {
462 			rds_inc_put(inc);
463 			inc = NULL;
464 			rds_stats_inc(s_recv_deliver_raced);
465 			continue;
466 		}
467 
468 		if (ret < be32_to_cpu(inc->i_hdr.h_len)) {
469 			if (msg_flags & MSG_TRUNC)
470 				ret = be32_to_cpu(inc->i_hdr.h_len);
471 			msg->msg_flags |= MSG_TRUNC;
472 		}
473 
474 		if (rds_cmsg_recv(inc, msg)) {
475 			ret = -EFAULT;
476 			goto out;
477 		}
478 
479 		rds_stats_inc(s_recv_delivered);
480 
481 		sin = (struct sockaddr_in *)msg->msg_name;
482 		if (sin) {
483 			sin->sin_family = AF_INET;
484 			sin->sin_port = inc->i_hdr.h_sport;
485 			sin->sin_addr.s_addr = inc->i_saddr;
486 			memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
487 		}
488 		break;
489 	}
490 
491 	if (inc)
492 		rds_inc_put(inc);
493 
494 out:
495 	return ret;
496 }
497 
498 /*
499  * The socket is being shut down and we're asked to drop messages that were
500  * queued for recvmsg.  The caller has unbound the socket so the receive path
501  * won't queue any more incoming fragments or messages on the socket.
502  */
503 void rds_clear_recv_queue(struct rds_sock *rs)
504 {
505 	struct sock *sk = rds_rs_to_sk(rs);
506 	struct rds_incoming *inc, *tmp;
507 	unsigned long flags;
508 
509 	write_lock_irqsave(&rs->rs_recv_lock, flags);
510 	list_for_each_entry_safe(inc, tmp, &rs->rs_recv_queue, i_item) {
511 		rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
512 				      -be32_to_cpu(inc->i_hdr.h_len),
513 				      inc->i_hdr.h_dport);
514 		list_del_init(&inc->i_item);
515 		rds_inc_put(inc);
516 	}
517 	write_unlock_irqrestore(&rs->rs_recv_lock, flags);
518 }
519 
520 /*
521  * inc->i_saddr isn't used here because it is only set in the receive
522  * path.
523  */
524 void rds_inc_info_copy(struct rds_incoming *inc,
525 		       struct rds_info_iterator *iter,
526 		       __be32 saddr, __be32 daddr, int flip)
527 {
528 	struct rds_info_message minfo;
529 
530 	minfo.seq = be64_to_cpu(inc->i_hdr.h_sequence);
531 	minfo.len = be32_to_cpu(inc->i_hdr.h_len);
532 
533 	if (flip) {
534 		minfo.laddr = daddr;
535 		minfo.faddr = saddr;
536 		minfo.lport = inc->i_hdr.h_dport;
537 		minfo.fport = inc->i_hdr.h_sport;
538 	} else {
539 		minfo.laddr = saddr;
540 		minfo.faddr = daddr;
541 		minfo.lport = inc->i_hdr.h_sport;
542 		minfo.fport = inc->i_hdr.h_dport;
543 	}
544 
545 	rds_info_copy(iter, &minfo, sizeof(minfo));
546 }
547