recv.c 15.3 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547
/*
 * Copyright (c) 2006 Oracle.  All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */
#include <linux/kernel.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <linux/in.h>
#include <linux/export.h>

#include "rds.h"

void rds_inc_init(struct rds_incoming *inc, struct rds_connection *conn,
		  __be32 saddr)
{
	atomic_set(&inc->i_refcount, 1);
	INIT_LIST_HEAD(&inc->i_item);
	inc->i_conn = conn;
	inc->i_saddr = saddr;
	inc->i_rdma_cookie = 0;
}
EXPORT_SYMBOL_GPL(rds_inc_init);

static void rds_inc_addref(struct rds_incoming *inc)
{
	rdsdebug("addref inc %p ref %d\n", inc, atomic_read(&inc->i_refcount));
	atomic_inc(&inc->i_refcount);
}

void rds_inc_put(struct rds_incoming *inc)
{
	rdsdebug("put inc %p ref %d\n", inc, atomic_read(&inc->i_refcount));
	if (atomic_dec_and_test(&inc->i_refcount)) {
		BUG_ON(!list_empty(&inc->i_item));

		inc->i_conn->c_trans->inc_free(inc);
	}
}
EXPORT_SYMBOL_GPL(rds_inc_put);

static void rds_recv_rcvbuf_delta(struct rds_sock *rs, struct sock *sk,
				  struct rds_cong_map *map,
				  int delta, __be16 port)
{
	int now_congested;

	if (delta == 0)
		return;

	rs->rs_rcv_bytes += delta;
	now_congested = rs->rs_rcv_bytes > rds_sk_rcvbuf(rs);

	rdsdebug("rs %p (%pI4:%u) recv bytes %d buf %d "
	  "now_cong %d delta %d\n",
	  rs, &rs->rs_bound_addr,
	  ntohs(rs->rs_bound_port), rs->rs_rcv_bytes,
	  rds_sk_rcvbuf(rs), now_congested, delta);

	/* wasn't -> am congested */
	if (!rs->rs_congested && now_congested) {
		rs->rs_congested = 1;
		rds_cong_set_bit(map, port);
		rds_cong_queue_updates(map);
	}
	/* was -> aren't congested */
	/* Require more free space before reporting uncongested to prevent
	   bouncing cong/uncong state too often */
	else if (rs->rs_congested && (rs->rs_rcv_bytes < (rds_sk_rcvbuf(rs)/2))) {
		rs->rs_congested = 0;
		rds_cong_clear_bit(map, port);
		rds_cong_queue_updates(map);
	}

	/* do nothing if no change in cong state */
}

/*
 * Process all extension headers that come with this message.
 */
static void rds_recv_incoming_exthdrs(struct rds_incoming *inc, struct rds_sock *rs)
{
	struct rds_header *hdr = &inc->i_hdr;
	unsigned int pos = 0, type, len;
	union {
		struct rds_ext_header_version version;
		struct rds_ext_header_rdma rdma;
		struct rds_ext_header_rdma_dest rdma_dest;
	} buffer;

	while (1) {
		len = sizeof(buffer);
		type = rds_message_next_extension(hdr, &pos, &buffer, &len);
		if (type == RDS_EXTHDR_NONE)
			break;
		/* Process extension header here */
		switch (type) {
		case RDS_EXTHDR_RDMA:
			rds_rdma_unuse(rs, be32_to_cpu(buffer.rdma.h_rdma_rkey), 0);
			break;

		case RDS_EXTHDR_RDMA_DEST:
			/* We ignore the size for now. We could stash it
			 * somewhere and use it for error checking. */
			inc->i_rdma_cookie = rds_rdma_make_cookie(
					be32_to_cpu(buffer.rdma_dest.h_rdma_rkey),
					be32_to_cpu(buffer.rdma_dest.h_rdma_offset));

			break;
		}
	}
}

/*
 * The transport must make sure that this is serialized against other
 * rx and conn reset on this specific conn.
 *
 * We currently assert that only one fragmented message will be sent
 * down a connection at a time.  This lets us reassemble in the conn
 * instead of per-flow which means that we don't have to go digging through
 * flows to tear down partial reassembly progress on conn failure and
 * we save flow lookup and locking for each frag arrival.  It does mean
 * that small messages will wait behind large ones.  Fragmenting at all
 * is only to reduce the memory consumption of pre-posted buffers.
 *
 * The caller passes in saddr and daddr instead of us getting it from the
 * conn.  This lets loopback, who only has one conn for both directions,
 * tell us which roles the addrs in the conn are playing for this message.
 */
void rds_recv_incoming(struct rds_connection *conn, __be32 saddr, __be32 daddr,
		       struct rds_incoming *inc, gfp_t gfp)
{
	struct rds_sock *rs = NULL;
	struct sock *sk;
	unsigned long flags;

	inc->i_conn = conn;
	inc->i_rx_jiffies = jiffies;

	rdsdebug("conn %p next %llu inc %p seq %llu len %u sport %u dport %u "
		 "flags 0x%x rx_jiffies %lu\n", conn,
		 (unsigned long long)conn->c_next_rx_seq,
		 inc,
		 (unsigned long long)be64_to_cpu(inc->i_hdr.h_sequence),
		 be32_to_cpu(inc->i_hdr.h_len),
		 be16_to_cpu(inc->i_hdr.h_sport),
		 be16_to_cpu(inc->i_hdr.h_dport),
		 inc->i_hdr.h_flags,
		 inc->i_rx_jiffies);

	/*
	 * Sequence numbers should only increase.  Messages get their
	 * sequence number as they're queued in a sending conn.  They
	 * can be dropped, though, if the sending socket is closed before
	 * they hit the wire.  So sequence numbers can skip forward
	 * under normal operation.  They can also drop back in the conn
	 * failover case as previously sent messages are resent down the
	 * new instance of a conn.  We drop those, otherwise we have
	 * to assume that the next valid seq does not come after a
	 * hole in the fragment stream.
	 *
	 * The headers don't give us a way to realize if fragments of
	 * a message have been dropped.  We assume that frags that arrive
	 * to a flow are part of the current message on the flow that is
	 * being reassembled.  This means that senders can't drop messages
	 * from the sending conn until all their frags are sent.
	 *
	 * XXX we could spend more on the wire to get more robust failure
	 * detection, arguably worth it to avoid data corruption.
	 */
	if (be64_to_cpu(inc->i_hdr.h_sequence) < conn->c_next_rx_seq &&
	    (inc->i_hdr.h_flags & RDS_FLAG_RETRANSMITTED)) {
		rds_stats_inc(s_recv_drop_old_seq);
		goto out;
	}
	conn->c_next_rx_seq = be64_to_cpu(inc->i_hdr.h_sequence) + 1;

	if (rds_sysctl_ping_enable && inc->i_hdr.h_dport == 0) {
		rds_stats_inc(s_recv_ping);
		rds_send_pong(conn, inc->i_hdr.h_sport);
		goto out;
	}

	rs = rds_find_bound(daddr, inc->i_hdr.h_dport);
	if (!rs) {
		rds_stats_inc(s_recv_drop_no_sock);
		goto out;
	}

	/* Process extension headers */
	rds_recv_incoming_exthdrs(inc, rs);

	/* We can be racing with rds_release() which marks the socket dead. */
	sk = rds_rs_to_sk(rs);

	/* serialize with rds_release -> sock_orphan */
	write_lock_irqsave(&rs->rs_recv_lock, flags);
	if (!sock_flag(sk, SOCK_DEAD)) {
		rdsdebug("adding inc %p to rs %p's recv queue\n", inc, rs);
		rds_stats_inc(s_recv_queued);
		rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
				      be32_to_cpu(inc->i_hdr.h_len),
				      inc->i_hdr.h_dport);
		rds_inc_addref(inc);
		list_add_tail(&inc->i_item, &rs->rs_recv_queue);
		__rds_wake_sk_sleep(sk);
	} else {
		rds_stats_inc(s_recv_drop_dead_sock);
	}
	write_unlock_irqrestore(&rs->rs_recv_lock, flags);

out:
	if (rs)
		rds_sock_put(rs);
}
EXPORT_SYMBOL_GPL(rds_recv_incoming);

/*
 * be very careful here.  This is being called as the condition in
 * wait_event_*() needs to cope with being called many times.
 */
static int rds_next_incoming(struct rds_sock *rs, struct rds_incoming **inc)
{
	unsigned long flags;

	if (!*inc) {
		read_lock_irqsave(&rs->rs_recv_lock, flags);
		if (!list_empty(&rs->rs_recv_queue)) {
			*inc = list_entry(rs->rs_recv_queue.next,
					  struct rds_incoming,
					  i_item);
			rds_inc_addref(*inc);
		}
		read_unlock_irqrestore(&rs->rs_recv_lock, flags);
	}

	return *inc != NULL;
}

static int rds_still_queued(struct rds_sock *rs, struct rds_incoming *inc,
			    int drop)
{
	struct sock *sk = rds_rs_to_sk(rs);
	int ret = 0;
	unsigned long flags;

	write_lock_irqsave(&rs->rs_recv_lock, flags);
	if (!list_empty(&inc->i_item)) {
		ret = 1;
		if (drop) {
			/* XXX make sure this i_conn is reliable */
			rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
					      -be32_to_cpu(inc->i_hdr.h_len),
					      inc->i_hdr.h_dport);
			list_del_init(&inc->i_item);
			rds_inc_put(inc);
		}
	}
	write_unlock_irqrestore(&rs->rs_recv_lock, flags);

	rdsdebug("inc %p rs %p still %d dropped %d\n", inc, rs, ret, drop);
	return ret;
}

/*
 * Pull errors off the error queue.
 * If msghdr is NULL, we will just purge the error queue.
 */
int rds_notify_queue_get(struct rds_sock *rs, struct msghdr *msghdr)
{
	struct rds_notifier *notifier;
	struct rds_rdma_notify cmsg = { 0 }; /* fill holes with zero */
	unsigned int count = 0, max_messages = ~0U;
	unsigned long flags;
	LIST_HEAD(copy);
	int err = 0;


	/* put_cmsg copies to user space and thus may sleep. We can't do this
	 * with rs_lock held, so first grab as many notifications as we can stuff
	 * in the user provided cmsg buffer. We don't try to copy more, to avoid
	 * losing notifications - except when the buffer is so small that it wouldn't
	 * even hold a single notification. Then we give him as much of this single
	 * msg as we can squeeze in, and set MSG_CTRUNC.
	 */
	if (msghdr) {
		max_messages = msghdr->msg_controllen / CMSG_SPACE(sizeof(cmsg));
		if (!max_messages)
			max_messages = 1;
	}

	spin_lock_irqsave(&rs->rs_lock, flags);
	while (!list_empty(&rs->rs_notify_queue) && count < max_messages) {
		notifier = list_entry(rs->rs_notify_queue.next,
				struct rds_notifier, n_list);
		list_move(&notifier->n_list, &copy);
		count++;
	}
	spin_unlock_irqrestore(&rs->rs_lock, flags);

	if (!count)
		return 0;

	while (!list_empty(&copy)) {
		notifier = list_entry(copy.next, struct rds_notifier, n_list);

		if (msghdr) {
			cmsg.user_token = notifier->n_user_token;
			cmsg.status = notifier->n_status;

			err = put_cmsg(msghdr, SOL_RDS, RDS_CMSG_RDMA_STATUS,
				       sizeof(cmsg), &cmsg);
			if (err)
				break;
		}

		list_del_init(&notifier->n_list);
		kfree(notifier);
	}

	/* If we bailed out because of an error in put_cmsg,
	 * we may be left with one or more notifications that we
	 * didn't process. Return them to the head of the list. */
	if (!list_empty(&copy)) {
		spin_lock_irqsave(&rs->rs_lock, flags);
		list_splice(&copy, &rs->rs_notify_queue);
		spin_unlock_irqrestore(&rs->rs_lock, flags);
	}

	return err;
}

/*
 * Queue a congestion notification
 */
static int rds_notify_cong(struct rds_sock *rs, struct msghdr *msghdr)
{
	uint64_t notify = rs->rs_cong_notify;
	unsigned long flags;
	int err;

	err = put_cmsg(msghdr, SOL_RDS, RDS_CMSG_CONG_UPDATE,
			sizeof(notify), &notify);
	if (err)
		return err;

	spin_lock_irqsave(&rs->rs_lock, flags);
	rs->rs_cong_notify &= ~notify;
	spin_unlock_irqrestore(&rs->rs_lock, flags);

	return 0;
}

/*
 * Receive any control messages.
 */
static int rds_cmsg_recv(struct rds_incoming *inc, struct msghdr *msg)
{
	int ret = 0;

	if (inc->i_rdma_cookie) {
		ret = put_cmsg(msg, SOL_RDS, RDS_CMSG_RDMA_DEST,
				sizeof(inc->i_rdma_cookie), &inc->i_rdma_cookie);
		if (ret)
			return ret;
	}

	return 0;
}

int rds_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
		size_t size, int msg_flags)
{
	struct sock *sk = sock->sk;
	struct rds_sock *rs = rds_sk_to_rs(sk);
	long timeo;
	int ret = 0, nonblock = msg_flags & MSG_DONTWAIT;
	DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
	struct rds_incoming *inc = NULL;

	/* udp_recvmsg()->sock_recvtimeo() gets away without locking too.. */
	timeo = sock_rcvtimeo(sk, nonblock);

	rdsdebug("size %zu flags 0x%x timeo %ld\n", size, msg_flags, timeo);

	if (msg_flags & MSG_OOB)
		goto out;

	while (1) {
		/* If there are pending notifications, do those - and nothing else */
		if (!list_empty(&rs->rs_notify_queue)) {
			ret = rds_notify_queue_get(rs, msg);
			break;
		}

		if (rs->rs_cong_notify) {
			ret = rds_notify_cong(rs, msg);
			break;
		}

		if (!rds_next_incoming(rs, &inc)) {
			if (nonblock) {
				ret = -EAGAIN;
				break;
			}

			timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
					(!list_empty(&rs->rs_notify_queue) ||
					 rs->rs_cong_notify ||
					 rds_next_incoming(rs, &inc)), timeo);
			rdsdebug("recvmsg woke inc %p timeo %ld\n", inc,
				 timeo);
			if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
				continue;

			ret = timeo;
			if (ret == 0)
				ret = -ETIMEDOUT;
			break;
		}

		rdsdebug("copying inc %p from %pI4:%u to user\n", inc,
			 &inc->i_conn->c_faddr,
			 ntohs(inc->i_hdr.h_sport));
		ret = inc->i_conn->c_trans->inc_copy_to_user(inc, msg->msg_iov,
							     size);
		if (ret < 0)
			break;

		/*
		 * if the message we just copied isn't at the head of the
		 * recv queue then someone else raced us to return it, try
		 * to get the next message.
		 */
		if (!rds_still_queued(rs, inc, !(msg_flags & MSG_PEEK))) {
			rds_inc_put(inc);
			inc = NULL;
			rds_stats_inc(s_recv_deliver_raced);
			continue;
		}

		if (ret < be32_to_cpu(inc->i_hdr.h_len)) {
			if (msg_flags & MSG_TRUNC)
				ret = be32_to_cpu(inc->i_hdr.h_len);
			msg->msg_flags |= MSG_TRUNC;
		}

		if (rds_cmsg_recv(inc, msg)) {
			ret = -EFAULT;
			goto out;
		}

		rds_stats_inc(s_recv_delivered);

		if (sin) {
			sin->sin_family = AF_INET;
			sin->sin_port = inc->i_hdr.h_sport;
			sin->sin_addr.s_addr = inc->i_saddr;
			memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
			msg->msg_namelen = sizeof(*sin);
		}
		break;
	}

	if (inc)
		rds_inc_put(inc);

out:
	return ret;
}

/*
 * The socket is being shut down and we're asked to drop messages that were
 * queued for recvmsg.  The caller has unbound the socket so the receive path
 * won't queue any more incoming fragments or messages on the socket.
 */
void rds_clear_recv_queue(struct rds_sock *rs)
{
	struct sock *sk = rds_rs_to_sk(rs);
	struct rds_incoming *inc, *tmp;
	unsigned long flags;

	write_lock_irqsave(&rs->rs_recv_lock, flags);
	list_for_each_entry_safe(inc, tmp, &rs->rs_recv_queue, i_item) {
		rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
				      -be32_to_cpu(inc->i_hdr.h_len),
				      inc->i_hdr.h_dport);
		list_del_init(&inc->i_item);
		rds_inc_put(inc);
	}
	write_unlock_irqrestore(&rs->rs_recv_lock, flags);
}

/*
 * inc->i_saddr isn't used here because it is only set in the receive
 * path.
 */
void rds_inc_info_copy(struct rds_incoming *inc,
		       struct rds_info_iterator *iter,
		       __be32 saddr, __be32 daddr, int flip)
{
	struct rds_info_message minfo;

	minfo.seq = be64_to_cpu(inc->i_hdr.h_sequence);
	minfo.len = be32_to_cpu(inc->i_hdr.h_len);

	if (flip) {
		minfo.laddr = daddr;
		minfo.faddr = saddr;
		minfo.lport = inc->i_hdr.h_dport;
		minfo.fport = inc->i_hdr.h_sport;
	} else {
		minfo.laddr = saddr;
		minfo.faddr = daddr;
		minfo.lport = inc->i_hdr.h_sport;
		minfo.fport = inc->i_hdr.h_dport;
	}

	rds_info_copy(iter, &minfo, sizeof(minfo));
}