linux/net/rds/recv.c
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   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
  40void 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
  50void 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
  56void 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
  66static 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 */
 105static 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 */
 154void 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
 236out:
 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 */
 245static 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
 263static 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 */
 292int 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 */
 359static 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 */
 380static 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
 394int 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
 490out:
 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 */
 499void 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 */
 520void 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}
 543