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