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