Root/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
41void 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}
50EXPORT_SYMBOL_GPL(rds_inc_init);
51
52void 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}
57EXPORT_SYMBOL_GPL(rds_inc_addref);
58
59void 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}
68EXPORT_SYMBOL_GPL(rds_inc_put);
69
70static 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 */
109static 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 */
158void 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
240out:
241    if (rs)
242        rds_sock_put(rs);
243}
244EXPORT_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 */
250static 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
268static 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 */
297int 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 */
364static 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 */
385static 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
399int 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
496out:
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 */
505void 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 */
526void 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}
549

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