/*
 * 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"

/* 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);

        rds_remove_bound(rs);

        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_set_transport(struct rds_sock *rs, char __user *optval,
                             int optlen)
{
        int t_type;

        if (rs->rs_transport)
                return -EOPNOTSUPP; /* previously attached to transport */

        if (optlen != sizeof(int))
                return -EINVAL;

        if (copy_from_user(&t_type, (int __user *)optval, sizeof(t_type)))
                return -EFAULT;

        if (t_type < 0 || t_type >= RDS_TRANS_COUNT)
                return -EINVAL;

        rs->rs_transport = rds_trans_get(t_type);

        return rs->rs_transport ? 0 : -ENOPROTOOPT;
}

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;
        case SO_RDS_TRANSPORT:
                lock_sock(sock->sk);
                ret = rds_set_transport(rs, optval, optlen);
                release_sock(sock->sk);
                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;
        int trans;

        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;
        case SO_RDS_TRANSPORT:
                if (len < sizeof(int)) {
                        ret = -EINVAL;
                        break;
                }
                trans = (rs->rs_transport ? rs->rs_transport->t_type :
                         RDS_TRANS_NONE); /* unbound */
                if (put_user(trans, (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 void rds_sock_destruct(struct sock *sk)
{
        struct rds_sock *rs = rds_sk_to_rs(sk);

        WARN_ON((&rs->rs_item != rs->rs_item.next ||
                 &rs->rs_item != rs->rs_item.prev));
}

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;
        sk->sk_destruct         = rds_sock_destruct;

        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, kern);
        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_bind_lock_destroy();
        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_bind_lock_init();
        if (ret)
                goto out;

        ret = rds_conn_init();
        if (ret)
                goto out_bind;

        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_bind:
        rds_bind_lock_destroy();
out:
        return ret;
}
module_init(rds_init);

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

MODULE_AUTHOR("Oracle Corporation <rds-devel@oss.oracle.com>");
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);