/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2012, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 */

#include "socklnd.h"

int
ksocknal_lib_get_conn_addrs(struct ksock_conn *conn)
{
        int rc = lnet_sock_getaddr(conn->ksnc_sock, 1, &conn->ksnc_ipaddr,
                                   &conn->ksnc_port);

        /* Didn't need the {get,put}connsock dance to deref ksnc_sock... */
        LASSERT(!conn->ksnc_closing);

        if (rc) {
                CERROR("Error %d getting sock peer IP\n", rc);
                return rc;
        }

        rc = lnet_sock_getaddr(conn->ksnc_sock, 0, &conn->ksnc_myipaddr, NULL);
        if (rc) {
                CERROR("Error %d getting sock local IP\n", rc);
                return rc;
        }

        return 0;
}

int
ksocknal_lib_zc_capable(struct ksock_conn *conn)
{
        int caps = conn->ksnc_sock->sk->sk_route_caps;

        if (conn->ksnc_proto == &ksocknal_protocol_v1x)
                return 0;

        /*
         * ZC if the socket supports scatter/gather and doesn't need software
         * checksums
         */
        return ((caps & NETIF_F_SG) && (caps & NETIF_F_CSUM_MASK));
}

int
ksocknal_lib_send_iov(struct ksock_conn *conn, struct ksock_tx *tx)
{
        struct msghdr msg = {.msg_flags = MSG_DONTWAIT};
        struct socket *sock = conn->ksnc_sock;
        int nob, i;

        if (*ksocknal_tunables.ksnd_enable_csum && /* checksum enabled */
            conn->ksnc_proto == &ksocknal_protocol_v2x && /* V2.x connection  */
            tx->tx_nob == tx->tx_resid           && /* frist sending    */
            !tx->tx_msg.ksm_csum)                    /* not checksummed  */
                ksocknal_lib_csum_tx(tx);

        for (nob = i = 0; i < tx->tx_niov; i++)
                nob += tx->tx_iov[i].iov_len;

        if (!list_empty(&conn->ksnc_tx_queue) ||
            nob < tx->tx_resid)
                msg.msg_flags |= MSG_MORE;

        iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC,
                      tx->tx_iov, tx->tx_niov, nob);
        return sock_sendmsg(sock, &msg);
}

int
ksocknal_lib_send_kiov(struct ksock_conn *conn, struct ksock_tx *tx)
{
        struct socket *sock = conn->ksnc_sock;
        lnet_kiov_t *kiov = tx->tx_kiov;
        int rc;
        int nob;

        /* Not NOOP message */
        LASSERT(tx->tx_lnetmsg);

        if (tx->tx_msg.ksm_zc_cookies[0]) {
                /* Zero copy is enabled */
                struct sock *sk = sock->sk;
                struct page *page = kiov->bv_page;
                int offset = kiov->bv_offset;
                int fragsize = kiov->bv_len;
                int msgflg = MSG_DONTWAIT;

                CDEBUG(D_NET, "page %p + offset %x for %d\n",
                       page, offset, kiov->bv_len);

                if (!list_empty(&conn->ksnc_tx_queue) ||
                    fragsize < tx->tx_resid)
                        msgflg |= MSG_MORE;

                if (sk->sk_prot->sendpage) {
                        rc = sk->sk_prot->sendpage(sk, page,
                                                   offset, fragsize, msgflg);
                } else {
                        rc = tcp_sendpage(sk, page, offset, fragsize, msgflg);
                }
        } else {
                struct msghdr msg = {.msg_flags = MSG_DONTWAIT};
                int i;

                for (nob = i = 0; i < tx->tx_nkiov; i++)
                        nob += kiov[i].bv_len;

                if (!list_empty(&conn->ksnc_tx_queue) ||
                    nob < tx->tx_resid)
                        msg.msg_flags |= MSG_MORE;

                iov_iter_bvec(&msg.msg_iter, WRITE | ITER_BVEC,
                              kiov, tx->tx_nkiov, nob);
                rc = sock_sendmsg(sock, &msg);
        }
        return rc;
}

void
ksocknal_lib_eager_ack(struct ksock_conn *conn)
{
        int opt = 1;
        struct socket *sock = conn->ksnc_sock;

        /*
         * Remind the socket to ACK eagerly.  If I don't, the socket might
         * think I'm about to send something it could piggy-back the ACK
         * on, introducing delay in completing zero-copy sends in my
         * peer.
         */
        kernel_setsockopt(sock, SOL_TCP, TCP_QUICKACK, (char *)&opt,
                          sizeof(opt));
}

int
ksocknal_lib_recv_iov(struct ksock_conn *conn)
{
        unsigned int niov = conn->ksnc_rx_niov;
        struct kvec *iov = conn->ksnc_rx_iov;
        struct msghdr msg = {
                .msg_flags = 0
        };
        int nob;
        int i;
        int rc;
        int fragnob;
        int sum;
        __u32 saved_csum;

        LASSERT(niov > 0);

        for (nob = i = 0; i < niov; i++)
                nob += iov[i].iov_len;

        LASSERT(nob <= conn->ksnc_rx_nob_wanted);

        iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, iov, niov, nob);
        rc = sock_recvmsg(conn->ksnc_sock, &msg, MSG_DONTWAIT);

        saved_csum = 0;
        if (conn->ksnc_proto == &ksocknal_protocol_v2x) {
                saved_csum = conn->ksnc_msg.ksm_csum;
                conn->ksnc_msg.ksm_csum = 0;
        }

        if (saved_csum) {
                /* accumulate checksum */
                for (i = 0, sum = rc; sum > 0; i++, sum -= fragnob) {
                        LASSERT(i < niov);

                        fragnob = iov[i].iov_len;
                        if (fragnob > sum)
                                fragnob = sum;

                        conn->ksnc_rx_csum = ksocknal_csum(conn->ksnc_rx_csum,
                                                           iov[i].iov_base, fragnob);
                }
                conn->ksnc_msg.ksm_csum = saved_csum;
        }

        return rc;
}

int
ksocknal_lib_recv_kiov(struct ksock_conn *conn)
{
        unsigned int niov = conn->ksnc_rx_nkiov;
        lnet_kiov_t   *kiov = conn->ksnc_rx_kiov;
        struct msghdr msg = {
                .msg_flags = 0
        };
        int nob;
        int i;
        int rc;
        void *base;
        int sum;
        int fragnob;

        for (nob = i = 0; i < niov; i++)
                nob += kiov[i].bv_len;

        LASSERT(nob <= conn->ksnc_rx_nob_wanted);

        iov_iter_bvec(&msg.msg_iter, READ | ITER_BVEC, kiov, niov, nob);
        rc = sock_recvmsg(conn->ksnc_sock, &msg, MSG_DONTWAIT);

        if (conn->ksnc_msg.ksm_csum) {
                for (i = 0, sum = rc; sum > 0; i++, sum -= fragnob) {
                        LASSERT(i < niov);

                        base = kmap(kiov[i].bv_page) + kiov[i].bv_offset;
                        fragnob = kiov[i].bv_len;
                        if (fragnob > sum)
                                fragnob = sum;

                        conn->ksnc_rx_csum = ksocknal_csum(conn->ksnc_rx_csum,
                                                           base, fragnob);

                        kunmap(kiov[i].bv_page);
                }
        }
        return rc;
}

void
ksocknal_lib_csum_tx(struct ksock_tx *tx)
{
        int i;
        __u32 csum;
        void *base;

        LASSERT(tx->tx_iov[0].iov_base == &tx->tx_msg);
        LASSERT(tx->tx_conn);
        LASSERT(tx->tx_conn->ksnc_proto == &ksocknal_protocol_v2x);

        tx->tx_msg.ksm_csum = 0;

        csum = ksocknal_csum(~0, tx->tx_iov[0].iov_base,
                             tx->tx_iov[0].iov_len);

        if (tx->tx_kiov) {
                for (i = 0; i < tx->tx_nkiov; i++) {
                        base = kmap(tx->tx_kiov[i].bv_page) +
                               tx->tx_kiov[i].bv_offset;

                        csum = ksocknal_csum(csum, base, tx->tx_kiov[i].bv_len);

                        kunmap(tx->tx_kiov[i].bv_page);
                }
        } else {
                for (i = 1; i < tx->tx_niov; i++)
                        csum = ksocknal_csum(csum, tx->tx_iov[i].iov_base,
                                             tx->tx_iov[i].iov_len);
        }

        if (*ksocknal_tunables.ksnd_inject_csum_error) {
                csum++;
                *ksocknal_tunables.ksnd_inject_csum_error = 0;
        }

        tx->tx_msg.ksm_csum = csum;
}

int
ksocknal_lib_get_conn_tunables(struct ksock_conn *conn, int *txmem, int *rxmem, int *nagle)
{
        struct socket *sock = conn->ksnc_sock;
        int len;
        int rc;

        rc = ksocknal_connsock_addref(conn);
        if (rc) {
                LASSERT(conn->ksnc_closing);
                *txmem = *rxmem = *nagle = 0;
                return -ESHUTDOWN;
        }

        rc = lnet_sock_getbuf(sock, txmem, rxmem);
        if (!rc) {
                len = sizeof(*nagle);
                rc = kernel_getsockopt(sock, SOL_TCP, TCP_NODELAY,
                                       (char *)nagle, &len);
        }

        ksocknal_connsock_decref(conn);

        if (!rc)
                *nagle = !*nagle;
        else
                *txmem = *rxmem = *nagle = 0;

        return rc;
}

int
ksocknal_lib_setup_sock(struct socket *sock)
{
        int rc;
        int option;
        int keep_idle;
        int keep_intvl;
        int keep_count;
        int do_keepalive;
        struct linger linger;

        sock->sk->sk_allocation = GFP_NOFS;

        /*
         * Ensure this socket aborts active sends immediately when we close
         * it.
         */
        linger.l_onoff = 0;
        linger.l_linger = 0;

        rc = kernel_setsockopt(sock, SOL_SOCKET, SO_LINGER, (char *)&linger,
                               sizeof(linger));
        if (rc) {
                CERROR("Can't set SO_LINGER: %d\n", rc);
                return rc;
        }

        option = -1;
        rc = kernel_setsockopt(sock, SOL_TCP, TCP_LINGER2, (char *)&option,
                               sizeof(option));
        if (rc) {
                CERROR("Can't set SO_LINGER2: %d\n", rc);
                return rc;
        }

        if (!*ksocknal_tunables.ksnd_nagle) {
                option = 1;

                rc = kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY,
                                       (char *)&option, sizeof(option));
                if (rc) {
                        CERROR("Can't disable nagle: %d\n", rc);
                        return rc;
                }
        }

        rc = lnet_sock_setbuf(sock, *ksocknal_tunables.ksnd_tx_buffer_size,
                              *ksocknal_tunables.ksnd_rx_buffer_size);
        if (rc) {
                CERROR("Can't set buffer tx %d, rx %d buffers: %d\n",
                       *ksocknal_tunables.ksnd_tx_buffer_size,
                       *ksocknal_tunables.ksnd_rx_buffer_size, rc);
                return rc;
        }

/* TCP_BACKOFF_* sockopt tunables unsupported in stock kernels */

        /* snapshot tunables */
        keep_idle  = *ksocknal_tunables.ksnd_keepalive_idle;
        keep_count = *ksocknal_tunables.ksnd_keepalive_count;
        keep_intvl = *ksocknal_tunables.ksnd_keepalive_intvl;

        do_keepalive = (keep_idle > 0 && keep_count > 0 && keep_intvl > 0);

        option = (do_keepalive ? 1 : 0);
        rc = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (char *)&option,
                               sizeof(option));
        if (rc) {
                CERROR("Can't set SO_KEEPALIVE: %d\n", rc);
                return rc;
        }

        if (!do_keepalive)
                return 0;

        rc = kernel_setsockopt(sock, SOL_TCP, TCP_KEEPIDLE, (char *)&keep_idle,
                               sizeof(keep_idle));
        if (rc) {
                CERROR("Can't set TCP_KEEPIDLE: %d\n", rc);
                return rc;
        }

        rc = kernel_setsockopt(sock, SOL_TCP, TCP_KEEPINTVL,
                               (char *)&keep_intvl, sizeof(keep_intvl));
        if (rc) {
                CERROR("Can't set TCP_KEEPINTVL: %d\n", rc);
                return rc;
        }

        rc = kernel_setsockopt(sock, SOL_TCP, TCP_KEEPCNT, (char *)&keep_count,
                               sizeof(keep_count));
        if (rc) {
                CERROR("Can't set TCP_KEEPCNT: %d\n", rc);
                return rc;
        }

        return 0;
}

void
ksocknal_lib_push_conn(struct ksock_conn *conn)
{
        struct sock *sk;
        struct tcp_sock *tp;
        int nonagle;
        int val = 1;
        int rc;

        rc = ksocknal_connsock_addref(conn);
        if (rc)                     /* being shut down */
                return;

        sk = conn->ksnc_sock->sk;
        tp = tcp_sk(sk);

        lock_sock(sk);
        nonagle = tp->nonagle;
        tp->nonagle = 1;
        release_sock(sk);

        rc = kernel_setsockopt(conn->ksnc_sock, SOL_TCP, TCP_NODELAY,
                               (char *)&val, sizeof(val));
        LASSERT(!rc);

        lock_sock(sk);
        tp->nonagle = nonagle;
        release_sock(sk);

        ksocknal_connsock_decref(conn);
}

/*
 * socket call back in Linux
 */
static void
ksocknal_data_ready(struct sock *sk)
{
        struct ksock_conn *conn;

        /* interleave correctly with closing sockets... */
        LASSERT(!in_irq());
        read_lock(&ksocknal_data.ksnd_global_lock);

        conn = sk->sk_user_data;
        if (!conn) {         /* raced with ksocknal_terminate_conn */
                LASSERT(sk->sk_data_ready != &ksocknal_data_ready);
                sk->sk_data_ready(sk);
        } else {
                ksocknal_read_callback(conn);
        }

        read_unlock(&ksocknal_data.ksnd_global_lock);
}

static void
ksocknal_write_space(struct sock *sk)
{
        struct ksock_conn *conn;
        int wspace;
        int min_wpace;

        /* interleave correctly with closing sockets... */
        LASSERT(!in_irq());
        read_lock(&ksocknal_data.ksnd_global_lock);

        conn = sk->sk_user_data;
        wspace = sk_stream_wspace(sk);
        min_wpace = sk_stream_min_wspace(sk);

        CDEBUG(D_NET, "sk %p wspace %d low water %d conn %p%s%s%s\n",
               sk, wspace, min_wpace, conn,
               !conn ? "" : (conn->ksnc_tx_ready ?
                                      " ready" : " blocked"),
               !conn ? "" : (conn->ksnc_tx_scheduled ?
                                      " scheduled" : " idle"),
               !conn ? "" : (list_empty(&conn->ksnc_tx_queue) ?
                                      " empty" : " queued"));

        if (!conn) {         /* raced with ksocknal_terminate_conn */
                LASSERT(sk->sk_write_space != &ksocknal_write_space);
                sk->sk_write_space(sk);

                read_unlock(&ksocknal_data.ksnd_global_lock);
                return;
        }

        if (wspace >= min_wpace) {            /* got enough space */
                ksocknal_write_callback(conn);

                /*
                 * Clear SOCK_NOSPACE _after_ ksocknal_write_callback so the
                 * ENOMEM check in ksocknal_transmit is race-free (think about
                 * it).
                 */
                clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
        }

        read_unlock(&ksocknal_data.ksnd_global_lock);
}

void
ksocknal_lib_save_callback(struct socket *sock, struct ksock_conn *conn)
{
        conn->ksnc_saved_data_ready = sock->sk->sk_data_ready;
        conn->ksnc_saved_write_space = sock->sk->sk_write_space;
}

void
ksocknal_lib_set_callback(struct socket *sock,  struct ksock_conn *conn)
{
        sock->sk->sk_user_data = conn;
        sock->sk->sk_data_ready = ksocknal_data_ready;
        sock->sk->sk_write_space = ksocknal_write_space;
}

void
ksocknal_lib_reset_callback(struct socket *sock, struct ksock_conn *conn)
{
        /*
         * Remove conn's network callbacks.
         * NB I _have_ to restore the callback, rather than storing a noop,
         * since the socket could survive past this module being unloaded!!
         */
        sock->sk->sk_data_ready = conn->ksnc_saved_data_ready;
        sock->sk->sk_write_space = conn->ksnc_saved_write_space;

        /*
         * A callback could be in progress already; they hold a read lock
         * on ksnd_global_lock (to serialise with me) and NOOP if
         * sk_user_data is NULL.
         */
        sock->sk->sk_user_data = NULL;
}

int
ksocknal_lib_memory_pressure(struct ksock_conn *conn)
{
        int rc = 0;
        struct ksock_sched *sched;

        sched = conn->ksnc_scheduler;
        spin_lock_bh(&sched->kss_lock);

        if (!test_bit(SOCK_NOSPACE, &conn->ksnc_sock->flags) &&
            !conn->ksnc_tx_ready) {
                /*
                 * SOCK_NOSPACE is set when the socket fills
                 * and cleared in the write_space callback
                 * (which also sets ksnc_tx_ready).  If
                 * SOCK_NOSPACE and ksnc_tx_ready are BOTH
                 * zero, I didn't fill the socket and
                 * write_space won't reschedule me, so I
                 * return -ENOMEM to get my caller to retry
                 * after a timeout
                 */
                rc = -ENOMEM;
        }

        spin_unlock_bh(&sched->kss_lock);

        return rc;
}