af_rds.c

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/*
 * Copyright (c) 2006 Oracle.  All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/in.h>
#include <linux/poll.h>
#include <net/sock.h>

#include "rds.h"

char *rds_str_array(char **array, size_t elements, size_t index)
{
    if ((index < elements) && array[index])
        return array[index];
    else
        return "unknown";
}
EXPORT_SYMBOL(rds_str_array);

/* this is just used for stats gathering :/ */
static DEFINE_SPINLOCK(rds_sock_lock);
static unsigned long rds_sock_count;
static LIST_HEAD(rds_sock_list);
DECLARE_WAIT_QUEUE_HEAD(rds_poll_waitq);

/*
 * This is called as the final descriptor referencing this socket is closed.
 * We have to unbind the socket so that another socket can be bound to the
 * address it was using.
 *
 * We have to be careful about racing with the incoming path.  sock_orphan()
 * sets SOCK_DEAD and we use that as an indicator to the rx path that new
 * messages shouldn't be queued.
 */
static int rds_release(struct socket *sock)
{
    struct sock *sk = sock->sk;
    struct rds_sock *rs;

    if (!sk)
        goto out;

    rs = rds_sk_to_rs(sk);

    sock_orphan(sk);
    /* Note - rds_clear_recv_queue grabs rs_recv_lock, so
     * that ensures the recv path has completed messing
     * with the socket. */
    rds_clear_recv_queue(rs);
    rds_cong_remove_socket(rs);

    /*
     * the binding lookup hash uses rcu, we need to
     * make sure we sychronize_rcu before we free our
     * entry
     */
    rds_remove_bound(rs);
    synchronize_rcu();

    rds_send_drop_to(rs, NULL);
    rds_rdma_drop_keys(rs);
    rds_notify_queue_get(rs, NULL);

    spin_lock_bh(&rds_sock_lock);
    list_del_init(&rs->rs_item);
    rds_sock_count--;
    spin_unlock_bh(&rds_sock_lock);

    rds_trans_put(rs->rs_transport);

    sock->sk = NULL;
    sock_put(sk);
out:
    return 0;
}

/*
 * Careful not to race with rds_release -> sock_orphan which clears sk_sleep.
 * _bh() isn't OK here, we're called from interrupt handlers.  It's probably OK
 * to wake the waitqueue after sk_sleep is clear as we hold a sock ref, but
 * this seems more conservative.
 * NB - normally, one would use sk_callback_lock for this, but we can
 * get here from interrupts, whereas the network code grabs sk_callback_lock
 * with _lock_bh only - so relying on sk_callback_lock introduces livelocks.
 */
void rds_wake_sk_sleep(struct rds_sock *rs)
{
    unsigned long flags;

    read_lock_irqsave(&rs->rs_recv_lock, flags);
    __rds_wake_sk_sleep(rds_rs_to_sk(rs));
    read_unlock_irqrestore(&rs->rs_recv_lock, flags);
}

static int rds_getname(struct socket *sock, struct sockaddr *uaddr,
               int *uaddr_len, int peer)
{
    struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
    struct rds_sock *rs = rds_sk_to_rs(sock->sk);

    memset(sin->sin_zero, 0, sizeof(sin->sin_zero));

    /* racey, don't care */
    if (peer) {
        if (!rs->rs_conn_addr)
            return -ENOTCONN;

        sin->sin_port = rs->rs_conn_port;
        sin->sin_addr.s_addr = rs->rs_conn_addr;
    } else {
        sin->sin_port = rs->rs_bound_port;
        sin->sin_addr.s_addr = rs->rs_bound_addr;
    }

    sin->sin_family = AF_INET;

    *uaddr_len = sizeof(*sin);
    return 0;
}

/*
 * RDS' poll is without a doubt the least intuitive part of the interface,
 * as POLLIN and POLLOUT do not behave entirely as you would expect from
 * a network protocol.
 *
 * POLLIN is asserted if
 *  -   there is data on the receive queue.
 *  -   to signal that a previously congested destination may have become
 *  uncongested
 *  -   A notification has been queued to the socket (this can be a congestion
 *  update, or a RDMA completion).
 *
 * POLLOUT is asserted if there is room on the send queue. This does not mean
 * however, that the next sendmsg() call will succeed. If the application tries
 * to send to a congested destination, the system call may still fail (and
 * return ENOBUFS).
 */
static unsigned int rds_poll(struct file *file, struct socket *sock,
                 poll_table *wait)
{
    struct sock *sk = sock->sk;
    struct rds_sock *rs = rds_sk_to_rs(sk);
    unsigned int mask = 0;
    unsigned long flags;

    poll_wait(file, sk_sleep(sk), wait);

    if (rs->rs_seen_congestion)
        poll_wait(file, &rds_poll_waitq, wait);

    read_lock_irqsave(&rs->rs_recv_lock, flags);
    if (!rs->rs_cong_monitor) {
        /* When a congestion map was updated, we signal POLLIN for
         * "historical" reasons. Applications can also poll for
         * WRBAND instead. */
        if (rds_cong_updated_since(&rs->rs_cong_track))
            mask |= (POLLIN | POLLRDNORM | POLLWRBAND);
    } else {
        spin_lock(&rs->rs_lock);
        if (rs->rs_cong_notify)
            mask |= (POLLIN | POLLRDNORM);
        spin_unlock(&rs->rs_lock);
    }
    if (!list_empty(&rs->rs_recv_queue) ||
        !list_empty(&rs->rs_notify_queue))
        mask |= (POLLIN | POLLRDNORM);
    if (rs->rs_snd_bytes < rds_sk_sndbuf(rs))
        mask |= (POLLOUT | POLLWRNORM);
    read_unlock_irqrestore(&rs->rs_recv_lock, flags);

    /* clear state any time we wake a seen-congested socket */
    if (mask)
        rs->rs_seen_congestion = 0;

    return mask;
}

static int rds_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
    return -ENOIOCTLCMD;
}

static int rds_cancel_sent_to(struct rds_sock *rs, char __user *optval,
                  int len)
{
    struct sockaddr_in sin;
    int ret = 0;

    /* racing with another thread binding seems ok here */
    if (rs->rs_bound_addr == 0) {
        ret = -ENOTCONN; /* XXX not a great errno */
        goto out;
    }

    if (len < sizeof(struct sockaddr_in)) {
        ret = -EINVAL;
        goto out;
    }

    if (copy_from_user(&sin, optval, sizeof(sin))) {
        ret = -EFAULT;
        goto out;
    }

    rds_send_drop_to(rs, &sin);
out:
    return ret;
}

static int rds_set_bool_option(unsigned char *optvar, char __user *optval,
                   int optlen)
{
    int value;

    if (optlen < sizeof(int))
        return -EINVAL;
    if (get_user(value, (int __user *) optval))
        return -EFAULT;
    *optvar = !!value;
    return 0;
}

static int rds_cong_monitor(struct rds_sock *rs, char __user *optval,
                int optlen)
{
    int ret;

    ret = rds_set_bool_option(&rs->rs_cong_monitor, optval, optlen);
    if (ret == 0) {
        if (rs->rs_cong_monitor) {
            rds_cong_add_socket(rs);
        } else {
            rds_cong_remove_socket(rs);
            rs->rs_cong_mask = 0;
            rs->rs_cong_notify = 0;
        }
    }
    return ret;
}

static int rds_setsockopt(struct socket *sock, int level, int optname,
              char __user *optval, unsigned int optlen)
{
    struct rds_sock *rs = rds_sk_to_rs(sock->sk);
    int ret;

    if (level != SOL_RDS) {
        ret = -ENOPROTOOPT;
        goto out;
    }

    switch (optname) {
    case RDS_CANCEL_SENT_TO:
        ret = rds_cancel_sent_to(rs, optval, optlen);
        break;
    case RDS_GET_MR:
        ret = rds_get_mr(rs, optval, optlen);
        break;
    case RDS_GET_MR_FOR_DEST:
        ret = rds_get_mr_for_dest(rs, optval, optlen);
        break;
    case RDS_FREE_MR:
        ret = rds_free_mr(rs, optval, optlen);
        break;
    case RDS_RECVERR:
        ret = rds_set_bool_option(&rs->rs_recverr, optval, optlen);
        break;
    case RDS_CONG_MONITOR:
        ret = rds_cong_monitor(rs, optval, optlen);
        break;
    default:
        ret = -ENOPROTOOPT;
    }
out:
    return ret;
}

static int rds_getsockopt(struct socket *sock, int level, int optname,
              char __user *optval, int __user *optlen)
{
    struct rds_sock *rs = rds_sk_to_rs(sock->sk);
    int ret = -ENOPROTOOPT, len;

    if (level != SOL_RDS)
        goto out;

    if (get_user(len, optlen)) {
        ret = -EFAULT;
        goto out;
    }

    switch (optname) {
    case RDS_INFO_FIRST ... RDS_INFO_LAST:
        ret = rds_info_getsockopt(sock, optname, optval,
                      optlen);
        break;

    case RDS_RECVERR:
        if (len < sizeof(int))
            ret = -EINVAL;
        else
        if (put_user(rs->rs_recverr, (int __user *) optval) ||
            put_user(sizeof(int), optlen))
            ret = -EFAULT;
        else
            ret = 0;
        break;
    default:
        break;
    }

out:
    return ret;

}

static int rds_connect(struct socket *sock, struct sockaddr *uaddr,
               int addr_len, int flags)
{
    struct sock *sk = sock->sk;
    struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
    struct rds_sock *rs = rds_sk_to_rs(sk);
    int ret = 0;

    lock_sock(sk);

    if (addr_len != sizeof(struct sockaddr_in)) {
        ret = -EINVAL;
        goto out;
    }

    if (sin->sin_family != AF_INET) {
        ret = -EAFNOSUPPORT;
        goto out;
    }

    if (sin->sin_addr.s_addr == htonl(INADDR_ANY)) {
        ret = -EDESTADDRREQ;
        goto out;
    }

    rs->rs_conn_addr = sin->sin_addr.s_addr;
    rs->rs_conn_port = sin->sin_port;

out:
    release_sock(sk);
    return ret;
}

static struct proto rds_proto = {
    .name     = "RDS",
    .owner    = THIS_MODULE,
    .obj_size = sizeof(struct rds_sock),
};

static const struct proto_ops rds_proto_ops = {
    .family =   AF_RDS,
    .owner =    THIS_MODULE,
    .release =  rds_release,
    .bind =     rds_bind,
    .connect =  rds_connect,
    .socketpair =   sock_no_socketpair,
    .accept =   sock_no_accept,
    .getname =  rds_getname,
    .poll =     rds_poll,
    .ioctl =    rds_ioctl,
    .listen =   sock_no_listen,
    .shutdown = sock_no_shutdown,
    .setsockopt =   rds_setsockopt,
    .getsockopt =   rds_getsockopt,
    .sendmsg =  rds_sendmsg,
    .recvmsg =  rds_recvmsg,
    .mmap =     sock_no_mmap,
    .sendpage = sock_no_sendpage,
};

static int __rds_create(struct socket *sock, struct sock *sk, int protocol)
{
    struct rds_sock *rs;

    sock_init_data(sock, sk);
    sock->ops       = &rds_proto_ops;
    sk->sk_protocol     = protocol;

    rs = rds_sk_to_rs(sk);
    spin_lock_init(&rs->rs_lock);
    rwlock_init(&rs->rs_recv_lock);
    INIT_LIST_HEAD(&rs->rs_send_queue);
    INIT_LIST_HEAD(&rs->rs_recv_queue);
    INIT_LIST_HEAD(&rs->rs_notify_queue);
    INIT_LIST_HEAD(&rs->rs_cong_list);
    spin_lock_init(&rs->rs_rdma_lock);
    rs->rs_rdma_keys = RB_ROOT;

    spin_lock_bh(&rds_sock_lock);
    list_add_tail(&rs->rs_item, &rds_sock_list);
    rds_sock_count++;
    spin_unlock_bh(&rds_sock_lock);

    return 0;
}

static int rds_create(struct net *net, struct socket *sock, int protocol,
              int kern)
{
    struct sock *sk;

    if (sock->type != SOCK_SEQPACKET || protocol)
        return -ESOCKTNOSUPPORT;

    sk = sk_alloc(net, AF_RDS, GFP_ATOMIC, &rds_proto);
    if (!sk)
        return -ENOMEM;

    return __rds_create(sock, sk, protocol);
}

void rds_sock_addref(struct rds_sock *rs)
{
    sock_hold(rds_rs_to_sk(rs));
}

void rds_sock_put(struct rds_sock *rs)
{
    sock_put(rds_rs_to_sk(rs));
}

static const struct net_proto_family rds_family_ops = {
    .family =   AF_RDS,
    .create =   rds_create,
    .owner  =   THIS_MODULE,
};

static void rds_sock_inc_info(struct socket *sock, unsigned int len,
                  struct rds_info_iterator *iter,
                  struct rds_info_lengths *lens)
{
    struct rds_sock *rs;
    struct rds_incoming *inc;
    unsigned int total = 0;

    len /= sizeof(struct rds_info_message);

    spin_lock_bh(&rds_sock_lock);

    list_for_each_entry(rs, &rds_sock_list, rs_item) {
        read_lock(&rs->rs_recv_lock);

        /* XXX too lazy to maintain counts.. */
        list_for_each_entry(inc, &rs->rs_recv_queue, i_item) {
            total++;
            if (total <= len)
                rds_inc_info_copy(inc, iter, inc->i_saddr,
                          rs->rs_bound_addr, 1);
        }

        read_unlock(&rs->rs_recv_lock);
    }

    spin_unlock_bh(&rds_sock_lock);

    lens->nr = total;
    lens->each = sizeof(struct rds_info_message);
}

static void rds_sock_info(struct socket *sock, unsigned int len,
              struct rds_info_iterator *iter,
              struct rds_info_lengths *lens)
{
    struct rds_info_socket sinfo;
    struct rds_sock *rs;

    len /= sizeof(struct rds_info_socket);

    spin_lock_bh(&rds_sock_lock);

    if (len < rds_sock_count)
        goto out;

    list_for_each_entry(rs, &rds_sock_list, rs_item) {
        sinfo.sndbuf = rds_sk_sndbuf(rs);
        sinfo.rcvbuf = rds_sk_rcvbuf(rs);
        sinfo.bound_addr = rs->rs_bound_addr;
        sinfo.connected_addr = rs->rs_conn_addr;
        sinfo.bound_port = rs->rs_bound_port;
        sinfo.connected_port = rs->rs_conn_port;
        sinfo.inum = sock_i_ino(rds_rs_to_sk(rs));

        rds_info_copy(iter, &sinfo, sizeof(sinfo));
    }

out:
    lens->nr = rds_sock_count;
    lens->each = sizeof(struct rds_info_socket);

    spin_unlock_bh(&rds_sock_lock);
}

static void rds_exit(void)
{
    sock_unregister(rds_family_ops.family);
    proto_unregister(&rds_proto);
    rds_conn_exit();
    rds_cong_exit();
    rds_sysctl_exit();
    rds_threads_exit();
    rds_stats_exit();
    rds_page_exit();
    rds_info_deregister_func(RDS_INFO_SOCKETS, rds_sock_info);
    rds_info_deregister_func(RDS_INFO_RECV_MESSAGES, rds_sock_inc_info);
}
module_exit(rds_exit);

static int rds_init(void)
{
    int ret;

    ret = rds_conn_init();
    if (ret)
        goto out;
    ret = rds_threads_init();
    if (ret)
        goto out_conn;
    ret = rds_sysctl_init();
    if (ret)
        goto out_threads;
    ret = rds_stats_init();
    if (ret)
        goto out_sysctl;
    ret = proto_register(&rds_proto, 1);
    if (ret)
        goto out_stats;
    ret = sock_register(&rds_family_ops);
    if (ret)
        goto out_proto;

    rds_info_register_func(RDS_INFO_SOCKETS, rds_sock_info);
    rds_info_register_func(RDS_INFO_RECV_MESSAGES, rds_sock_inc_info);

    goto out;

out_proto:
    proto_unregister(&rds_proto);
out_stats:
    rds_stats_exit();
out_sysctl:
    rds_sysctl_exit();
out_threads:
    rds_threads_exit();
out_conn:
    rds_conn_exit();
    rds_cong_exit();
    rds_page_exit();
out:
    return ret;
}
module_init(rds_init);

#define DRV_VERSION     "4.0"
#define DRV_RELDATE     "Feb 12, 2009"

MODULE_AUTHOR("Oracle Corporation <[email protected]>");
MODULE_DESCRIPTION("RDS: Reliable Datagram Sockets"
           " v" DRV_VERSION " (" DRV_RELDATE ")");
MODULE_VERSION(DRV_VERSION);
MODULE_LICENSE("Dual BSD/GPL");
MODULE_ALIAS_NETPROTO(PF_RDS);