/*
 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2016 by Delphix. All rights reserved.
 */

/*
 * This file contains code imported from the OFED rds source file recv.c
 * Oracle elects to have and use the contents of rds_recv.c under and governed
 * by the OpenIB.org BSD license (see below for full license text). However,
 * the following notice accompanied the original version of this file:
 */

/*
 * 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 <sys/rds.h>

#include <sys/ib/clients/rdsv3/rdsv3.h>
#include <sys/ib/clients/rdsv3/rdma.h>
#include <sys/ib/clients/rdsv3/rdsv3_debug.h>

void
rdsv3_inc_init(struct rdsv3_incoming *inc, struct rdsv3_connection *conn,
    uint32_be_t saddr)
{
        RDSV3_DPRINTF5("rdsv3_inc_init", "Enter(inc: %p, conn: %p)", inc, conn);
        inc->i_refcount = 1;
        list_link_init(&inc->i_item);
        inc->i_conn = conn;
        inc->i_saddr = saddr;
        inc->i_rdma_cookie = 0;
}

void
rdsv3_inc_addref(struct rdsv3_incoming *inc)
{
        RDSV3_DPRINTF4("rdsv3_inc_addref",
            "addref inc %p ref %d", inc, atomic_get(&inc->i_refcount));
        atomic_inc_32(&inc->i_refcount);
}

void
rdsv3_inc_put(struct rdsv3_incoming *inc)
{
        RDSV3_DPRINTF4("rdsv3_inc_put", "put inc %p ref %d",
            inc, atomic_get(&inc->i_refcount));
        if (atomic_dec_and_test(&inc->i_refcount)) {
                ASSERT(!list_link_active(&inc->i_item));

                inc->i_conn->c_trans->inc_free(inc);
        }
}

/*ARGSUSED*/
static void
rdsv3_recv_rcvbuf_delta(struct rdsv3_sock *rs, struct rsock *sk,
    struct rdsv3_cong_map *map,
    int delta, uint16_be_t port)
{
        int now_congested;

        RDSV3_DPRINTF4("rdsv3_recv_rcvbuf_delta",
            "Enter(rs: %p, map: %p, delta: %d, port: %d)",
            rs, map, delta, port);

        if (delta == 0)
                return;

        rs->rs_rcv_bytes += delta;
        now_congested = rs->rs_rcv_bytes > rdsv3_sk_rcvbuf(rs);

        RDSV3_DPRINTF5("rdsv3_recv_rcvbuf_delta",
            "rs %p (%u.%u.%u.%u:%u) recv bytes %d buf %d "
            "now_cong %d delta %d",
            rs, NIPQUAD(rs->rs_bound_addr),
            (int)ntohs(rs->rs_bound_port), rs->rs_rcv_bytes,
            rdsv3_sk_rcvbuf(rs), now_congested, delta);

        /* wasn't -> am congested */
        if (!rs->rs_congested && now_congested) {
                rs->rs_congested = 1;
                rdsv3_cong_set_bit(map, port);
                rdsv3_cong_queue_updates(map);
        }
        /* was -> aren't congested */
        /*
         * Require more free space before reporting uncongested to prevent
         * bouncing cong/uncong state too often
         */
        else if (rs->rs_congested &&
            (rs->rs_rcv_bytes < (rdsv3_sk_rcvbuf(rs)/2))) {
                rs->rs_congested = 0;
                rdsv3_cong_clear_bit(map, port);
                rdsv3_cong_queue_updates(map);
        }

        /* do nothing if no change in cong state */

        RDSV3_DPRINTF4("rdsv3_recv_rcvbuf_delta", "Return(rs: %p)", rs);
}

/*
 * Process all extension headers that come with this message.
 */
static void
rdsv3_recv_incoming_exthdrs(struct rdsv3_incoming *inc, struct rdsv3_sock *rs)
{
        struct rdsv3_header *hdr = &inc->i_hdr;
        unsigned int pos = 0, type, len;
        union {
                struct rdsv3_ext_header_version version;
                struct rdsv3_ext_header_rdma rdma;
                struct rdsv3_ext_header_rdma_dest rdma_dest;
        } buffer;

        RDSV3_DPRINTF4("rdsv3_recv_incoming_exthdrs", "Enter");
        while (1) {
                len = sizeof (buffer);
                type = rdsv3_message_next_extension(hdr, &pos, &buffer, &len);
                if (type == RDSV3_EXTHDR_NONE)
                        break;
                RDSV3_DPRINTF4("recv_incoming_exthdrs", "type %d", type);
                /* Process extension header here */
                switch (type) {
                case RDSV3_EXTHDR_RDMA:
                        rdsv3_rdma_unuse(rs, ntohl(buffer.rdma.h_rdma_rkey),
                            0);
                        break;

                case RDSV3_EXTHDR_RDMA_DEST:
                        /*
                         * We ignore the size for now. We could stash it
                         * somewhere and use it for error checking.
                         */
                        inc->i_rdma_cookie = rdsv3_rdma_make_cookie(
                            ntohl(buffer.rdma_dest.h_rdma_rkey),
                            ntohl(buffer.rdma_dest.h_rdma_offset));

                        break;
                }
        }
        RDSV3_DPRINTF4("rdsv3_recv_incoming_exthdrs", "Return");
}

/*
 * The transport must make sure that this is serialized against other
 * rx and conn reset on this specific conn.
 *
 * We currently assert that only one fragmented message will be sent
 * down a connection at a time.  This lets us reassemble in the conn
 * instead of per-flow which means that we don't have to go digging through
 * flows to tear down partial reassembly progress on conn failure and
 * we save flow lookup and locking for each frag arrival.  It does mean
 * that small messages will wait behind large ones.  Fragmenting at all
 * is only to reduce the memory consumption of pre-posted buffers.
 *
 * The caller passes in saddr and daddr instead of us getting it from the
 * conn.  This lets loopback, who only has one conn for both directions,
 * tell us which roles the addrs in the conn are playing for this message.
 */
/* ARGSUSED */
void
rdsv3_recv_incoming(struct rdsv3_connection *conn, uint32_be_t saddr,
    uint32_be_t daddr, struct rdsv3_incoming *inc, int gfp)
{
        struct rdsv3_sock *rs = NULL;
        struct rsock *sk;

        inc->i_conn = conn;
        inc->i_rx_jiffies = jiffies;

        RDSV3_DPRINTF5("rdsv3_recv_incoming",
            "conn %p next %llu inc %p seq %llu len %u sport %u dport %u "
            "flags 0x%x rx_jiffies %lu", conn,
            (unsigned long long)conn->c_next_rx_seq,
            inc,
            (unsigned long long)ntohll(inc->i_hdr.h_sequence),
            ntohl(inc->i_hdr.h_len),
            ntohs(inc->i_hdr.h_sport),
            ntohs(inc->i_hdr.h_dport),
            inc->i_hdr.h_flags,
            inc->i_rx_jiffies);

        /*
         * Sequence numbers should only increase.  Messages get their
         * sequence number as they're queued in a sending conn.  They
         * can be dropped, though, if the sending socket is closed before
         * they hit the wire.  So sequence numbers can skip forward
         * under normal operation.  They can also drop back in the conn
         * failover case as previously sent messages are resent down the
         * new instance of a conn.  We drop those, otherwise we have
         * to assume that the next valid seq does not come after a
         * hole in the fragment stream.
         *
         * The headers don't give us a way to realize if fragments of
         * a message have been dropped.  We assume that frags that arrive
         * to a flow are part of the current message on the flow that is
         * being reassembled.  This means that senders can't drop messages
         * from the sending conn until all their frags are sent.
         *
         * XXX we could spend more on the wire to get more robust failure
         * detection, arguably worth it to avoid data corruption.
         */
        if (ntohll(inc->i_hdr.h_sequence) < conn->c_next_rx_seq &&
            (inc->i_hdr.h_flags & RDSV3_FLAG_RETRANSMITTED)) {
                rdsv3_stats_inc(s_recv_drop_old_seq);
                goto out;
        }
        conn->c_next_rx_seq = ntohll(inc->i_hdr.h_sequence) + 1;

        if (rdsv3_sysctl_ping_enable && inc->i_hdr.h_dport == 0) {
                rdsv3_stats_inc(s_recv_ping);
                (void) rdsv3_send_pong(conn, inc->i_hdr.h_sport);
                goto out;
        }

        rs = rdsv3_find_bound(conn, inc->i_hdr.h_dport);
        if (!rs) {
                rdsv3_stats_inc(s_recv_drop_no_sock);
                goto out;
        }

        /* Process extension headers */
        rdsv3_recv_incoming_exthdrs(inc, rs);

        /* We can be racing with rdsv3_release() which marks the socket dead. */
        sk = rdsv3_rs_to_sk(rs);

        /* serialize with rdsv3_release -> sock_orphan */
        rw_enter(&rs->rs_recv_lock, RW_WRITER);
        if (!rdsv3_sk_sock_flag(sk, SOCK_DEAD)) {
                int error, bytes;
                RDSV3_DPRINTF5("rdsv3_recv_incoming",
                    "adding inc %p to rs %p's recv queue", inc, rs);
                rdsv3_stats_inc(s_recv_queued);
                rdsv3_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
                    ntohl(inc->i_hdr.h_len),
                    inc->i_hdr.h_dport);
                rdsv3_inc_addref(inc);
                list_insert_tail(&rs->rs_recv_queue, inc);
                bytes = rs->rs_rcv_bytes;
                rw_exit(&rs->rs_recv_lock);

                __rdsv3_wake_sk_sleep(sk);

                /* wake up anyone waiting in poll */
                sk->sk_upcalls->su_recv(sk->sk_upper_handle, NULL,
                    bytes, 0, &error, NULL);
                if (error != 0) {
                        RDSV3_DPRINTF2("rdsv3_recv_incoming",
                            "su_recv returned: %d", error);
                }
        } else {
                rdsv3_stats_inc(s_recv_drop_dead_sock);
                rw_exit(&rs->rs_recv_lock);
        }

out:
        if (rs)
                rdsv3_sock_put(rs);
}

/*
 * be very careful here.  This is being called as the condition in
 * wait_event_*() needs to cope with being called many times.
 */
static int
rdsv3_next_incoming(struct rdsv3_sock *rs, struct rdsv3_incoming **inc)
{
        if (!*inc) {
                rw_enter(&rs->rs_recv_lock, RW_READER);
                if (!list_is_empty(&rs->rs_recv_queue)) {
                        *inc = list_head(&rs->rs_recv_queue);
                        rdsv3_inc_addref(*inc);
                }
                rw_exit(&rs->rs_recv_lock);
        }

        return (*inc != NULL);
}

static int
rdsv3_still_queued(struct rdsv3_sock *rs, struct rdsv3_incoming *inc,
    int drop)
{
        struct rsock *sk = rdsv3_rs_to_sk(rs);
        int ret = 0;

        RDSV3_DPRINTF4("rdsv3_still_queued", "Enter rs: %p inc: %p drop: %d",
            rs, inc, drop);

        rw_enter(&rs->rs_recv_lock, RW_WRITER);
        if (list_link_active(&inc->i_item)) {
                ret = 1;
                if (drop) {
                        /* XXX make sure this i_conn is reliable */
                        rdsv3_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
                            -ntohl(inc->i_hdr.h_len),
                            inc->i_hdr.h_dport);
                        list_remove_node(&inc->i_item);
                        rdsv3_inc_put(inc);
                }
        }
        rw_exit(&rs->rs_recv_lock);

        RDSV3_DPRINTF5("rdsv3_still_queued",
            "inc %p rs %p still %d dropped %d", inc, rs, ret, drop);
        return (ret);
}

/*
 * Pull errors off the error queue.
 * If msghdr is NULL, we will just purge the error queue.
 */
int
rdsv3_notify_queue_get(struct rdsv3_sock *rs, struct msghdr *msghdr)
{
        struct rdsv3_notifier *notifier;
        struct rds_rdma_notify cmsg;
        unsigned int count = 0, max_messages = ~0U;
        list_t copy;
        int err = 0;

        RDSV3_DPRINTF4("rdsv3_notify_queue_get", "Enter(rs: %p)", rs);

        list_create(&copy, sizeof (struct rdsv3_notifier),
            offsetof(struct rdsv3_notifier, n_list));


        /*
         * put_cmsg copies to user space and thus may sleep. We can't do this
         * with rs_lock held, so first grab as many notifications as we can
         * stuff
         * in the user provided cmsg buffer. We don't try to copy more, to avoid
         * losing notifications - except when the buffer is so small that
         * it wouldn't
         * even hold a single notification. Then we give as much of this
         * single
         * msg as we can squeeze in, and set MSG_CTRUNC.
         */
        if (msghdr) {
                max_messages =
                    msghdr->msg_controllen / CMSG_SPACE(sizeof (cmsg));
                if (!max_messages)
                        max_messages = 1;
        }

        mutex_enter(&rs->rs_lock);
        while (!list_is_empty(&rs->rs_notify_queue) && count < max_messages) {
                notifier = list_remove_head(&rs->rs_notify_queue);
                list_insert_tail(&copy, notifier);
                count++;
        }
        mutex_exit(&rs->rs_lock);

        if (!count)
                return (0);

        while (!list_is_empty(&copy)) {
                notifier = list_remove_head(&copy);

                if (msghdr) {
                        cmsg.user_token = notifier->n_user_token;
                        cmsg.status  = notifier->n_status;

                        err = rdsv3_put_cmsg(msghdr, SOL_RDS,
                            RDS_CMSG_RDMA_STATUS, sizeof (cmsg), &cmsg);
                        if (err)
                                break;
                }

                kmem_free(notifier, sizeof (struct rdsv3_notifier));
        }

        /*
         * If we bailed out because of an error in put_cmsg,
         * we may be left with one or more notifications that we
         * didn't process. Return them to the head of the list.
         */
        if (!list_is_empty(&copy)) {
                mutex_enter(&rs->rs_lock);
                list_splice(&copy, &rs->rs_notify_queue);
                mutex_exit(&rs->rs_lock);
        }

        RDSV3_DPRINTF4("rdsv3_notify_queue_get", "Return(rs: %p)", rs);

        return (err);
}

/*
 * Queue a congestion notification
 */
static int
rdsv3_notify_cong(struct rdsv3_sock *rs, struct msghdr *msghdr)
{
        uint64_t notify = rs->rs_cong_notify;
        int err;

        err = rdsv3_put_cmsg(msghdr, SOL_RDS, RDS_CMSG_CONG_UPDATE,
            sizeof (notify), &notify);
        if (err)
                return (err);

        mutex_enter(&rs->rs_lock);
        rs->rs_cong_notify &= ~notify;
        mutex_exit(&rs->rs_lock);

        return (0);
}

/*
 * Receive any control messages.
 */
static int
rdsv3_cmsg_recv(struct rdsv3_incoming *inc, struct msghdr *msg)
{
        int ret = 0;
        if (inc->i_rdma_cookie) {
                ret = rdsv3_put_cmsg(msg, SOL_RDS, RDS_CMSG_RDMA_DEST,
                    sizeof (inc->i_rdma_cookie), &inc->i_rdma_cookie);
        }
        return (ret);
}

int
rdsv3_recvmsg(struct rdsv3_sock *rs, uio_t *uio,
    struct nmsghdr *msg, size_t size, int msg_flags)
{
        struct rsock *sk = rdsv3_rs_to_sk(rs);
        int ret = 0;
        struct sockaddr_in *sin = NULL;
        struct rdsv3_incoming *inc = NULL;
        boolean_t nonblock = B_FALSE;

        RDSV3_DPRINTF4("rdsv3_recvmsg",
            "Enter(rs: %p size: %d msg_flags: 0x%x)", rs, size, msg_flags);

        if ((uio->uio_fmode & (FNDELAY | FNONBLOCK)) ||
            (msg_flags & MSG_DONTWAIT))
                nonblock = B_TRUE;

        if (msg_flags & MSG_OOB)
                goto out;

        /* mark the first cmsg position */
        if (msg) {
                msg->msg_control = NULL;
        }

        while (1) {
                /*
                 * If there are pending notifications, do those -
                 * and nothing else
                 */
                if (!list_is_empty(&rs->rs_notify_queue)) {
                        ret = rdsv3_notify_queue_get(rs, msg);

                        if (msg && msg->msg_namelen) {
                                sin = kmem_zalloc(sizeof (struct sockaddr_in),
                                    KM_SLEEP);
                                sin->sin_family = AF_INET_OFFLOAD;
                                if (inc) {
                                        sin->sin_port = inc->i_hdr.h_sport;
                                        sin->sin_addr.s_addr = inc->i_saddr;
                                }
                                msg->msg_namelen = sizeof (struct sockaddr_in);
                                msg->msg_name = sin;
                        }
                        break;
                }

                if (rs->rs_cong_notify) {
                        ret = rdsv3_notify_cong(rs, msg);
                        goto out;
                }

                if (!rdsv3_next_incoming(rs, &inc)) {
                        if (nonblock) {
                                ret = -EAGAIN;
                                break;
                        }

                        RDSV3_DPRINTF3("rdsv3_recvmsg",
                            "Before wait (rs: %p)", rs);

#if 0
                        ret = rdsv3_wait_sig(sk->sk_sleep,
                            !(list_is_empty(&rs->rs_notify_queue) &&
                            !rs->rs_cong_notify &&
                            !rdsv3_next_incoming(rs, &inc)));
                        if (ret == 0) {
                                /* signal/timeout pending */
                                RDSV3_DPRINTF2("rdsv3_recvmsg",
                                    "woke due to signal");
                                ret = -ERESTART;
                        }
#else
                        mutex_enter(&sk->sk_sleep->waitq_mutex);
                        sk->sk_sleep->waitq_waiters++;
                        while ((list_is_empty(&rs->rs_notify_queue) &&
                            !rs->rs_cong_notify &&
                            !rdsv3_next_incoming(rs, &inc))) {
                                ret = cv_wait_sig(&sk->sk_sleep->waitq_cv,
                                    &sk->sk_sleep->waitq_mutex);
                                if (ret == 0) {
                                        /* signal/timeout pending */
                                        RDSV3_DPRINTF2("rdsv3_recvmsg",
                                            "woke due to signal");
                                        ret = -EINTR;
                                        break;
                                }
                        }
                        sk->sk_sleep->waitq_waiters--;
                        mutex_exit(&sk->sk_sleep->waitq_mutex);
#endif

                        RDSV3_DPRINTF5("rdsv3_recvmsg",
                            "recvmsg woke rs: %p inc %p ret %d",
                            rs, inc, -ret);

                        if (ret < 0)
                                break;

                        /*
                         * if the wakeup was due to rs_notify_queue or
                         * rs_cong_notify then we need to handle those first.
                         */
                        continue;
                }

                RDSV3_DPRINTF5("rdsv3_recvmsg",
                    "copying inc %p from %u.%u.%u.%u:%u to user", inc,
                    NIPQUAD(inc->i_conn->c_faddr),
                    ntohs(inc->i_hdr.h_sport));

                ret = inc->i_conn->c_trans->inc_copy_to_user(inc, uio, size);
                if (ret < 0)
                        break;

                /*
                 * if the message we just copied isn't at the head of the
                 * recv queue then someone else raced us to return it, try
                 * to get the next message.
                 */
                if (!rdsv3_still_queued(rs, inc, !(msg_flags & MSG_PEEK))) {
                        rdsv3_inc_put(inc);
                        inc = NULL;
                        rdsv3_stats_inc(s_recv_deliver_raced);
                        continue;
                }

                if (ret < ntohl(inc->i_hdr.h_len)) {
                        if (msg_flags & MSG_TRUNC)
                                ret = ntohl(inc->i_hdr.h_len);
                        msg->msg_flags |= MSG_TRUNC;
                }

                if (rdsv3_cmsg_recv(inc, msg)) {
                        ret = -EFAULT;
                        goto out;
                }

                rdsv3_stats_inc(s_recv_delivered);

                if (msg->msg_namelen) {
                        sin = kmem_alloc(sizeof (struct sockaddr_in), KM_SLEEP);
                        sin->sin_family = AF_INET_OFFLOAD;
                        sin->sin_port = inc->i_hdr.h_sport;
                        sin->sin_addr.s_addr = inc->i_saddr;
                        (void) memset(sin->sin_zero, 0,
                            sizeof (sin->sin_zero));
                        msg->msg_namelen = sizeof (struct sockaddr_in);
                        msg->msg_name = sin;
                }
                break;
        }

        if (inc)
                rdsv3_inc_put(inc);

out:
        if (msg && msg->msg_control == NULL)
                msg->msg_controllen = 0;

        RDSV3_DPRINTF4("rdsv3_recvmsg", "Return(rs: %p, ret: %d)", rs, ret);

        return (ret);
}

/*
 * The socket is being shut down and we're asked to drop messages that were
 * queued for recvmsg.  The caller has unbound the socket so the receive path
 * won't queue any more incoming fragments or messages on the socket.
 */
void
rdsv3_clear_recv_queue(struct rdsv3_sock *rs)
{
        struct rsock *sk = rdsv3_rs_to_sk(rs);
        struct rdsv3_incoming *inc, *tmp;

        RDSV3_DPRINTF4("rdsv3_clear_recv_queue", "Enter(rs: %p)", rs);

        rw_enter(&rs->rs_recv_lock, RW_WRITER);
        RDSV3_FOR_EACH_LIST_NODE_SAFE(inc, tmp, &rs->rs_recv_queue, i_item) {
                rdsv3_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
                    -ntohl(inc->i_hdr.h_len),
                    inc->i_hdr.h_dport);
                list_remove_node(&inc->i_item);
                rdsv3_inc_put(inc);
        }
        rw_exit(&rs->rs_recv_lock);

        RDSV3_DPRINTF4("rdsv3_clear_recv_queue", "Return(rs: %p)", rs);
}

/*
 * inc->i_saddr isn't used here because it is only set in the receive
 * path.
 */
void
rdsv3_inc_info_copy(struct rdsv3_incoming *inc,
    struct rdsv3_info_iterator *iter,
    uint32_be_t saddr, uint32_be_t daddr, int flip)
{
        struct rds_info_message minfo;

        minfo.seq = ntohll(inc->i_hdr.h_sequence);
        minfo.len = ntohl(inc->i_hdr.h_len);

        if (flip) {
                minfo.laddr = daddr;
                minfo.faddr = saddr;
                minfo.lport = inc->i_hdr.h_dport;
                minfo.fport = inc->i_hdr.h_sport;
        } else {
                minfo.laddr = saddr;
                minfo.faddr = daddr;
                minfo.lport = inc->i_hdr.h_sport;
                minfo.fport = inc->i_hdr.h_dport;
        }

        rdsv3_info_copy(iter, &minfo, sizeof (minfo));
}