net/rds/recv.c

   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 #include <linux/export.h>
  38
  39 #include "rds.h"
  40
  41 void rds_inc_init(struct rds_incoming *inc, struct rds_connection *conn,
  42                   __be32 saddr)
  43 {
  44         atomic_set(&inc->i_refcount, 1);
  45         INIT_LIST_HEAD(&inc->i_item);
  46         inc->i_conn = conn;
  47         inc->i_saddr = saddr;
  48         inc->i_rdma_cookie = 0;
  49 }
  50 EXPORT_SYMBOL_GPL(rds_inc_init);
  51
  52 static void rds_inc_addref(struct rds_incoming *inc)
  53 {
  54         rdsdebug("addref inc %p ref %d\n", inc, atomic_read(&inc->i_refcount));
  55         atomic_inc(&inc->i_refcount);
  56 }
  57
  58 void rds_inc_put(struct rds_incoming *inc)
  59 {
  60         rdsdebug("put inc %p ref %d\n", inc, atomic_read(&inc->i_refcount));
  61         if (atomic_dec_and_test(&inc->i_refcount)) {
  62                 BUG_ON(!list_empty(&inc->i_item));
  63
  64                 inc->i_conn->c_trans->inc_free(inc);
  65         }
  66 }
  67 EXPORT_SYMBOL_GPL(rds_inc_put);
  68
  69 static void rds_recv_rcvbuf_delta(struct rds_sock *rs, struct sock *sk,
  70                                   struct rds_cong_map *map,
  71                                   int delta, __be16 port)
  72 {
  73         int now_congested;
  74
  75         if (delta == 0)
  76                 return;
  77
  78         rs->rs_rcv_bytes += delta;
  79         now_congested = rs->rs_rcv_bytes > rds_sk_rcvbuf(rs);
  80
  81         rdsdebug("rs %p (%pI4:%u) recv bytes %d buf %d "
  82           "now_cong %d delta %d\n",
  83           rs, &rs->rs_bound_addr,
  84           ntohs(rs->rs_bound_port), rs->rs_rcv_bytes,
  85           rds_sk_rcvbuf(rs), now_congested, delta);
  86
  87         /* wasn't -> am congested */
  88         if (!rs->rs_congested && now_congested) {
  89                 rs->rs_congested = 1;
  90                 rds_cong_set_bit(map, port);
  91                 rds_cong_queue_updates(map);
  92         }
  93         /* was -> aren't congested */
  94         /* Require more free space before reporting uncongested to prevent
  95            bouncing cong/uncong state too often */
  96         else if (rs->rs_congested && (rs->rs_rcv_bytes < (rds_sk_rcvbuf(rs)/2))) {
  97                 rs->rs_congested = 0;
  98                 rds_cong_clear_bit(map, port);
  99                 rds_cong_queue_updates(map);
 100         }
 101
 102         /* do nothing if no change in cong state */
 103 }
 104
 105 /*
 106  * Process all extension headers that come with this message.
 107  */
 108 static void rds_recv_incoming_exthdrs(struct rds_incoming *inc, struct rds_sock *rs)
 109 {
 110         struct rds_header *hdr = &inc->i_hdr;
 111         unsigned int pos = 0, type, len;
 112         union {
 113                 struct rds_ext_header_version version;
 114                 struct rds_ext_header_rdma rdma;
 115                 struct rds_ext_header_rdma_dest rdma_dest;
 116         } buffer;
 117
 118         while (1) {
 119                 len = sizeof(buffer);
 120                 type = rds_message_next_extension(hdr, &pos, &buffer, &len);
 121                 if (type == RDS_EXTHDR_NONE)
 122                         break;
 123                 /* Process extension header here */
 124                 switch (type) {
 125                 case RDS_EXTHDR_RDMA:
 126                         rds_rdma_unuse(rs, be32_to_cpu(buffer.rdma.h_rdma_rkey), 0);
 127                         break;
 128
 129                 case RDS_EXTHDR_RDMA_DEST:
 130                         /* We ignore the size for now. We could stash it
 131                          * somewhere and use it for error checking. */
 132                         inc->i_rdma_cookie = rds_rdma_make_cookie(
 133                                         be32_to_cpu(buffer.rdma_dest.h_rdma_rkey),
 134                                         be32_to_cpu(buffer.rdma_dest.h_rdma_offset));
 135
 136                         break;
 137                 }
 138         }
 139 }
 140
 141 /*
 142  * The transport must make sure that this is serialized against other
 143  * rx and conn reset on this specific conn.
 144  *
 145  * We currently assert that only one fragmented message will be sent
 146  * down a connection at a time.  This lets us reassemble in the conn
 147  * instead of per-flow which means that we don't have to go digging through
 148  * flows to tear down partial reassembly progress on conn failure and
 149  * we save flow lookup and locking for each frag arrival.  It does mean
 150  * that small messages will wait behind large ones.  Fragmenting at all
 151  * is only to reduce the memory consumption of pre-posted buffers.
 152  *
 153  * The caller passes in saddr and daddr instead of us getting it from the
 154  * conn.  This lets loopback, who only has one conn for both directions,
 155  * tell us which roles the addrs in the conn are playing for this message.
 156  */
 157 void rds_recv_incoming(struct rds_connection *conn, __be32 saddr, __be32 daddr,
 158                        struct rds_incoming *inc, gfp_t gfp)
 159 {
 160         struct rds_sock *rs = NULL;
 161         struct sock *sk;
 162         unsigned long flags;
 163
 164         inc->i_conn = conn;
 165         inc->i_rx_jiffies = jiffies;
 166
 167         rdsdebug("conn %p next %llu inc %p seq %llu len %u sport %u dport %u "
 168                  "flags 0x%x rx_jiffies %lu\n", conn,
 169                  (unsigned long long)conn->c_next_rx_seq,
 170                  inc,
 171                  (unsigned long long)be64_to_cpu(inc->i_hdr.h_sequence),
 172                  be32_to_cpu(inc->i_hdr.h_len),
 173                  be16_to_cpu(inc->i_hdr.h_sport),
 174                  be16_to_cpu(inc->i_hdr.h_dport),
 175                  inc->i_hdr.h_flags,
 176                  inc->i_rx_jiffies);
 177
 178         /*
 179          * Sequence numbers should only increase.  Messages get their
 180          * sequence number as they're queued in a sending conn.  They
 181          * can be dropped, though, if the sending socket is closed before
 182          * they hit the wire.  So sequence numbers can skip forward
 183          * under normal operation.  They can also drop back in the conn
 184          * failover case as previously sent messages are resent down the
 185          * new instance of a conn.  We drop those, otherwise we have
 186          * to assume that the next valid seq does not come after a
 187          * hole in the fragment stream.
 188          *
 189          * The headers don't give us a way to realize if fragments of
 190          * a message have been dropped.  We assume that frags that arrive
 191          * to a flow are part of the current message on the flow that is
 192          * being reassembled.  This means that senders can't drop messages
 193          * from the sending conn until all their frags are sent.
 194          *
 195          * XXX we could spend more on the wire to get more robust failure
 196          * detection, arguably worth it to avoid data corruption.
 197          */
 198         if (be64_to_cpu(inc->i_hdr.h_sequence) < conn->c_next_rx_seq &&
 199             (inc->i_hdr.h_flags & RDS_FLAG_RETRANSMITTED)) {
 200                 rds_stats_inc(s_recv_drop_old_seq);
 201                 goto out;
 202         }
 203         conn->c_next_rx_seq = be64_to_cpu(inc->i_hdr.h_sequence) + 1;
 204
 205         if (rds_sysctl_ping_enable && inc->i_hdr.h_dport == 0) {
 206                 rds_stats_inc(s_recv_ping);
 207                 rds_send_pong(conn, inc->i_hdr.h_sport);
 208                 goto out;
 209         }
 210
 211         rs = rds_find_bound(daddr, inc->i_hdr.h_dport);
 212         if (!rs) {
 213                 rds_stats_inc(s_recv_drop_no_sock);
 214                 goto out;
 215         }
 216
 217         /* Process extension headers */
 218         rds_recv_incoming_exthdrs(inc, rs);
 219
 220         /* We can be racing with rds_release() which marks the socket dead. */
 221         sk = rds_rs_to_sk(rs);
 222
 223         /* serialize with rds_release -> sock_orphan */
 224         write_lock_irqsave(&rs->rs_recv_lock, flags);
 225         if (!sock_flag(sk, SOCK_DEAD)) {
 226                 rdsdebug("adding inc %p to rs %p's recv queue\n", inc, rs);
 227                 rds_stats_inc(s_recv_queued);
 228                 rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
 229                                       be32_to_cpu(inc->i_hdr.h_len),
 230                                       inc->i_hdr.h_dport);
 231                 rds_inc_addref(inc);
 232                 list_add_tail(&inc->i_item, &rs->rs_recv_queue);
 233                 __rds_wake_sk_sleep(sk);
 234         } else {
 235                 rds_stats_inc(s_recv_drop_dead_sock);
 236         }
 237         write_unlock_irqrestore(&rs->rs_recv_lock, flags);
 238
 239 out:
 240         if (rs)
 241                 rds_sock_put(rs);
 242 }
 243 EXPORT_SYMBOL_GPL(rds_recv_incoming);
 244
 245 /*
 246  * be very careful here.  This is being called as the condition in
 247  * wait_event_*() needs to cope with being called many times.
 248  */
 249 static int rds_next_incoming(struct rds_sock *rs, struct rds_incoming **inc)
 250 {
 251         unsigned long flags;
 252
 253         if (!*inc) {
 254                 read_lock_irqsave(&rs->rs_recv_lock, flags);
 255                 if (!list_empty(&rs->rs_recv_queue)) {
 256                         *inc = list_entry(rs->rs_recv_queue.next,
 257                                           struct rds_incoming,
 258                                           i_item);
 259                         rds_inc_addref(*inc);
 260                 }
 261                 read_unlock_irqrestore(&rs->rs_recv_lock, flags);
 262         }
 263
 264         return *inc != NULL;
 265 }
 266
 267 static int rds_still_queued(struct rds_sock *rs, struct rds_incoming *inc,
 268                             int drop)
 269 {
 270         struct sock *sk = rds_rs_to_sk(rs);
 271         int ret = 0;
 272         unsigned long flags;
 273
 274         write_lock_irqsave(&rs->rs_recv_lock, flags);
 275         if (!list_empty(&inc->i_item)) {
 276                 ret = 1;
 277                 if (drop) {
 278                         /* XXX make sure this i_conn is reliable */
 279                         rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
 280                                               -be32_to_cpu(inc->i_hdr.h_len),
 281                                               inc->i_hdr.h_dport);
 282                         list_del_init(&inc->i_item);
 283                         rds_inc_put(inc);
 284                 }
 285         }
 286         write_unlock_irqrestore(&rs->rs_recv_lock, flags);
 287
 288         rdsdebug("inc %p rs %p still %d dropped %d\n", inc, rs, ret, drop);
 289         return ret;
 290 }
 291
 292 /*
 293  * Pull errors off the error queue.
 294  * If msghdr is NULL, we will just purge the error queue.
 295  */
 296 int rds_notify_queue_get(struct rds_sock *rs, struct msghdr *msghdr)
 297 {
 298         struct rds_notifier *notifier;
 299         struct rds_rdma_notify cmsg = { 0 }; /* fill holes with zero */
 300         unsigned int count = 0, max_messages = ~0U;
 301         unsigned long flags;
 302         LIST_HEAD(copy);
 303         int err = 0;
 304
 305
 306         /* put_cmsg copies to user space and thus may sleep. We can't do this
 307          * with rs_lock held, so first grab as many notifications as we can stuff
 308          * in the user provided cmsg buffer. We don't try to copy more, to avoid
 309          * losing notifications - except when the buffer is so small that it wouldn't
 310          * even hold a single notification. Then we give him as much of this single
 311          * msg as we can squeeze in, and set MSG_CTRUNC.
 312          */
 313         if (msghdr) {
 314                 max_messages = msghdr->msg_controllen / CMSG_SPACE(sizeof(cmsg));
 315                 if (!max_messages)
 316                         max_messages = 1;
 317         }
 318
 319         spin_lock_irqsave(&rs->rs_lock, flags);
 320         while (!list_empty(&rs->rs_notify_queue) && count < max_messages) {
 321                 notifier = list_entry(rs->rs_notify_queue.next,
 322                                 struct rds_notifier, n_list);
 323                 list_move(&notifier->n_list, &copy);
 324                 count++;
 325         }
 326         spin_unlock_irqrestore(&rs->rs_lock, flags);
 327
 328         if (!count)
 329                 return 0;
 330
 331         while (!list_empty(&copy)) {
 332                 notifier = list_entry(copy.next, struct rds_notifier, n_list);
 333
 334                 if (msghdr) {
 335                         cmsg.user_token = notifier->n_user_token;
 336                         cmsg.status = notifier->n_status;
 337
 338                         err = put_cmsg(msghdr, SOL_RDS, RDS_CMSG_RDMA_STATUS,
 339                                        sizeof(cmsg), &cmsg);
 340                         if (err)
 341                                 break;
 342                 }
 343
 344                 list_del_init(&notifier->n_list);
 345                 kfree(notifier);
 346         }
 347
 348         /* If we bailed out because of an error in put_cmsg,
 349          * we may be left with one or more notifications that we
 350          * didn't process. Return them to the head of the list. */
 351         if (!list_empty(&copy)) {
 352                 spin_lock_irqsave(&rs->rs_lock, flags);
 353                 list_splice(&copy, &rs->rs_notify_queue);
 354                 spin_unlock_irqrestore(&rs->rs_lock, flags);
 355         }
 356
 357         return err;
 358 }
 359
 360 /*
 361  * Queue a congestion notification
 362  */
 363 static int rds_notify_cong(struct rds_sock *rs, struct msghdr *msghdr)
 364 {
 365         uint64_t notify = rs->rs_cong_notify;
 366         unsigned long flags;
 367         int err;
 368
 369         err = put_cmsg(msghdr, SOL_RDS, RDS_CMSG_CONG_UPDATE,
 370                         sizeof(notify), &notify);
 371         if (err)
 372                 return err;
 373
 374         spin_lock_irqsave(&rs->rs_lock, flags);
 375         rs->rs_cong_notify &= ~notify;
 376         spin_unlock_irqrestore(&rs->rs_lock, flags);
 377
 378         return 0;
 379 }
 380
 381 /*
 382  * Receive any control messages.
 383  */
 384 static int rds_cmsg_recv(struct rds_incoming *inc, struct msghdr *msg)
 385 {
 386         int ret = 0;
 387
 388         if (inc->i_rdma_cookie) {
 389                 ret = put_cmsg(msg, SOL_RDS, RDS_CMSG_RDMA_DEST,
 390                                 sizeof(inc->i_rdma_cookie), &inc->i_rdma_cookie);
 391                 if (ret)
 392                         return ret;
 393         }
 394
 395         return 0;
 396 }
 397
 398 int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
 399                 int msg_flags)
 400 {
 401         struct sock *sk = sock->sk;
 402         struct rds_sock *rs = rds_sk_to_rs(sk);
 403         long timeo;
 404         int ret = 0, nonblock = msg_flags & MSG_DONTWAIT;
 405         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 406         struct rds_incoming *inc = NULL;
 407
 408         /* udp_recvmsg()->sock_recvtimeo() gets away without locking too.. */
 409         timeo = sock_rcvtimeo(sk, nonblock);
 410
 411         rdsdebug("size %zu flags 0x%x timeo %ld\n", size, msg_flags, timeo);
 412
 413         if (msg_flags & MSG_OOB)
 414                 goto out;
 415
 416         while (1) {
 417                 struct iov_iter save;
 418                 /* If there are pending notifications, do those - and nothing else */
 419                 if (!list_empty(&rs->rs_notify_queue)) {
 420                         ret = rds_notify_queue_get(rs, msg);
 421                         break;
 422                 }
 423
 424                 if (rs->rs_cong_notify) {
 425                         ret = rds_notify_cong(rs, msg);
 426                         break;
 427                 }
 428
 429                 if (!rds_next_incoming(rs, &inc)) {
 430                         if (nonblock) {
 431                                 ret = -EAGAIN;
 432                                 break;
 433                         }
 434
 435                         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
 436                                         (!list_empty(&rs->rs_notify_queue) ||
 437                                          rs->rs_cong_notify ||
 438                                          rds_next_incoming(rs, &inc)), timeo);
 439                         rdsdebug("recvmsg woke inc %p timeo %ld\n", inc,
 440                                  timeo);
 441                         if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
 442                                 continue;
 443
 444                         ret = timeo;
 445                         if (ret == 0)
 446                                 ret = -ETIMEDOUT;
 447                         break;
 448                 }
 449
 450                 rdsdebug("copying inc %p from %pI4:%u to user\n", inc,
 451                          &inc->i_conn->c_faddr,
 452                          ntohs(inc->i_hdr.h_sport));
 453                 save = msg->msg_iter;
 454                 ret = inc->i_conn->c_trans->inc_copy_to_user(inc, &msg->msg_iter);
 455                 if (ret < 0)
 456                         break;
 457
 458                 /*
 459                  * if the message we just copied isn't at the head of the
 460                  * recv queue then someone else raced us to return it, try
 461                  * to get the next message.
 462                  */
 463                 if (!rds_still_queued(rs, inc, !(msg_flags & MSG_PEEK))) {
 464                         rds_inc_put(inc);
 465                         inc = NULL;
 466                         rds_stats_inc(s_recv_deliver_raced);
 467                         msg->msg_iter = save;
 468                         continue;
 469                 }
 470
 471                 if (ret < be32_to_cpu(inc->i_hdr.h_len)) {
 472                         if (msg_flags & MSG_TRUNC)
 473                                 ret = be32_to_cpu(inc->i_hdr.h_len);
 474                         msg->msg_flags |= MSG_TRUNC;
 475                 }
 476
 477                 if (rds_cmsg_recv(inc, msg)) {
 478                         ret = -EFAULT;
 479                         goto out;
 480                 }
 481
 482                 rds_stats_inc(s_recv_delivered);
 483
 484                 if (sin) {
 485                         sin->sin_family = AF_INET;
 486                         sin->sin_port = inc->i_hdr.h_sport;
 487                         sin->sin_addr.s_addr = inc->i_saddr;
 488                         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 489                         msg->msg_namelen = sizeof(*sin);
 490                 }
 491                 break;
 492         }
 493
 494         if (inc)
 495                 rds_inc_put(inc);
 496
 497 out:
 498         return ret;
 499 }
 500
 501 /*
 502  * The socket is being shut down and we're asked to drop messages that were
 503  * queued for recvmsg.  The caller has unbound the socket so the receive path
 504  * won't queue any more incoming fragments or messages on the socket.
 505  */
 506 void rds_clear_recv_queue(struct rds_sock *rs)
 507 {
 508         struct sock *sk = rds_rs_to_sk(rs);
 509         struct rds_incoming *inc, *tmp;
 510         unsigned long flags;
 511
 512         write_lock_irqsave(&rs->rs_recv_lock, flags);
 513         list_for_each_entry_safe(inc, tmp, &rs->rs_recv_queue, i_item) {
 514                 rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
 515                                       -be32_to_cpu(inc->i_hdr.h_len),
 516                                       inc->i_hdr.h_dport);
 517                 list_del_init(&inc->i_item);
 518                 rds_inc_put(inc);
 519         }
 520         write_unlock_irqrestore(&rs->rs_recv_lock, flags);
 521 }
 522
 523 /*
 524  * inc->i_saddr isn't used here because it is only set in the receive
 525  * path.
 526  */
 527 void rds_inc_info_copy(struct rds_incoming *inc,
 528                        struct rds_info_iterator *iter,
 529                        __be32 saddr, __be32 daddr, int flip)
 530 {
 531         struct rds_info_message minfo;
 532
 533         minfo.seq = be64_to_cpu(inc->i_hdr.h_sequence);
 534         minfo.len = be32_to_cpu(inc->i_hdr.h_len);
 535
 536         if (flip) {
 537                 minfo.laddr = daddr;
 538                 minfo.faddr = saddr;
 539                 minfo.lport = inc->i_hdr.h_dport;
 540                 minfo.fport = inc->i_hdr.h_sport;
 541         } else {
 542                 minfo.laddr = saddr;
 543                 minfo.faddr = daddr;
 544                 minfo.lport = inc->i_hdr.h_sport;
 545                 minfo.fport = inc->i_hdr.h_dport;
 546         }
 547
 548         rds_info_copy(iter, &minfo, sizeof(minfo));
 549 }