/*
 * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
 *
 * Copyright (c) 2012, Intel Corporation.
 *
 *   Author: Zach Brown <zab@zabbo.net>
 *   Author: Peter J. Braam <braam@clusterfs.com>
 *   Author: Phil Schwan <phil@clusterfs.com>
 *   Author: Eric Barton <eric@bartonsoftware.com>
 *
 *   This file is part of Portals, http://www.sf.net/projects/sandiaportals/
 *
 *   Portals is free software; you can redistribute it and/or
 *   modify it under the terms of version 2 of the GNU General Public
 *   License as published by the Free Software Foundation.
 *
 *   Portals 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 for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with Portals; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "socklnd.h"

/*
 * Protocol entries :
 *   pro_send_hello       : send hello message
 *   pro_recv_hello       : receive hello message
 *   pro_pack        : pack message header
 *   pro_unpack    : unpack message header
 *   pro_queue_tx_zcack() : Called holding BH lock: kss_lock
 *                        return 1 if ACK is piggybacked, otherwise return 0
 *   pro_queue_tx_msg()   : Called holding BH lock: kss_lock
 *                        return the ACK that piggybacked by my message, or NULL
 *   pro_handle_zcreq()   : handler of incoming ZC-REQ
 *   pro_handle_zcack()   : handler of incoming ZC-ACK
 *   pro_match_tx()       : Called holding glock
 */

static ksock_tx_t *
ksocknal_queue_tx_msg_v1(ksock_conn_t *conn, ksock_tx_t *tx_msg)
{
        /* V1.x, just enqueue it */
        list_add_tail(&tx_msg->tx_list, &conn->ksnc_tx_queue);
        return NULL;
}

void
ksocknal_next_tx_carrier(ksock_conn_t *conn)
{
        ksock_tx_t     *tx = conn->ksnc_tx_carrier;

        /* Called holding BH lock: conn->ksnc_scheduler->kss_lock */
        LASSERT (!list_empty(&conn->ksnc_tx_queue));
        LASSERT (tx != NULL);

        /* Next TX that can carry ZC-ACK or LNet message */
        if (tx->tx_list.next == &conn->ksnc_tx_queue) {
                /* no more packets queued */
                conn->ksnc_tx_carrier = NULL;
        } else {
                conn->ksnc_tx_carrier = list_entry(tx->tx_list.next,
                                                       ksock_tx_t, tx_list);
                LASSERT (conn->ksnc_tx_carrier->tx_msg.ksm_type == tx->tx_msg.ksm_type);
        }
}

static int
ksocknal_queue_tx_zcack_v2(ksock_conn_t *conn,
                           ksock_tx_t *tx_ack, __u64 cookie)
{
        ksock_tx_t *tx = conn->ksnc_tx_carrier;

        LASSERT (tx_ack == NULL ||
                 tx_ack->tx_msg.ksm_type == KSOCK_MSG_NOOP);

        /*
         * Enqueue or piggyback tx_ack / cookie
         * . no tx can piggyback cookie of tx_ack (or cookie), just
         *   enqueue the tx_ack (if tx_ack != NUL) and return NULL.
         * . There is tx can piggyback cookie of tx_ack (or cookie),
         *   piggyback the cookie and return the tx.
         */
        if (tx == NULL) {
                if (tx_ack != NULL) {
                        list_add_tail(&tx_ack->tx_list,
                                          &conn->ksnc_tx_queue);
                        conn->ksnc_tx_carrier = tx_ack;
                }
                return 0;
        }

        if (tx->tx_msg.ksm_type == KSOCK_MSG_NOOP) {
                /* tx is noop zc-ack, can't piggyback zc-ack cookie */
                if (tx_ack != NULL)
                        list_add_tail(&tx_ack->tx_list,
                                          &conn->ksnc_tx_queue);
                return 0;
        }

        LASSERT(tx->tx_msg.ksm_type == KSOCK_MSG_LNET);
        LASSERT(tx->tx_msg.ksm_zc_cookies[1] == 0);

        if (tx_ack != NULL)
                cookie = tx_ack->tx_msg.ksm_zc_cookies[1];

        /* piggyback the zc-ack cookie */
        tx->tx_msg.ksm_zc_cookies[1] = cookie;
        /* move on to the next TX which can carry cookie */
        ksocknal_next_tx_carrier(conn);

        return 1;
}

static ksock_tx_t *
ksocknal_queue_tx_msg_v2(ksock_conn_t *conn, ksock_tx_t *tx_msg)
{
        ksock_tx_t  *tx  = conn->ksnc_tx_carrier;

        /*
         * Enqueue tx_msg:
         * . If there is no NOOP on the connection, just enqueue
         *   tx_msg and return NULL
         * . If there is NOOP on the connection, piggyback the cookie
         *   and replace the NOOP tx, and return the NOOP tx.
         */
        if (tx == NULL) { /* nothing on queue */
                list_add_tail(&tx_msg->tx_list, &conn->ksnc_tx_queue);
                conn->ksnc_tx_carrier = tx_msg;
                return NULL;
        }

        if (tx->tx_msg.ksm_type == KSOCK_MSG_LNET) { /* nothing to carry */
                list_add_tail(&tx_msg->tx_list, &conn->ksnc_tx_queue);
                return NULL;
        }

        LASSERT (tx->tx_msg.ksm_type == KSOCK_MSG_NOOP);

        /* There is a noop zc-ack can be piggybacked */
        tx_msg->tx_msg.ksm_zc_cookies[1] = tx->tx_msg.ksm_zc_cookies[1];
        ksocknal_next_tx_carrier(conn);

        /* use new_tx to replace the noop zc-ack packet */
        list_add(&tx_msg->tx_list, &tx->tx_list);
        list_del(&tx->tx_list);

        return tx;
}

static int
ksocknal_queue_tx_zcack_v3(ksock_conn_t *conn,
                           ksock_tx_t *tx_ack, __u64 cookie)
{
        ksock_tx_t *tx;

        if (conn->ksnc_type != SOCKLND_CONN_ACK)
                return ksocknal_queue_tx_zcack_v2(conn, tx_ack, cookie);

        /* non-blocking ZC-ACK (to router) */
        LASSERT (tx_ack == NULL ||
                 tx_ack->tx_msg.ksm_type == KSOCK_MSG_NOOP);

        if ((tx = conn->ksnc_tx_carrier) == NULL) {
                if (tx_ack != NULL) {
                        list_add_tail(&tx_ack->tx_list,
                                          &conn->ksnc_tx_queue);
                        conn->ksnc_tx_carrier = tx_ack;
                }
                return 0;
        }

        /* conn->ksnc_tx_carrier != NULL */

        if (tx_ack != NULL)
                cookie = tx_ack->tx_msg.ksm_zc_cookies[1];

        if (cookie == SOCKNAL_KEEPALIVE_PING) /* ignore keepalive PING */
                return 1;

        if (tx->tx_msg.ksm_zc_cookies[1] == SOCKNAL_KEEPALIVE_PING) {
                /* replace the keepalive PING with a real ACK */
                LASSERT (tx->tx_msg.ksm_zc_cookies[0] == 0);
                tx->tx_msg.ksm_zc_cookies[1] = cookie;
                return 1;
        }

        if (cookie == tx->tx_msg.ksm_zc_cookies[0] ||
            cookie == tx->tx_msg.ksm_zc_cookies[1]) {
                CWARN("%s: duplicated ZC cookie: "LPU64"\n",
                      libcfs_id2str(conn->ksnc_peer->ksnp_id), cookie);
                return 1; /* XXX return error in the future */
        }

        if (tx->tx_msg.ksm_zc_cookies[0] == 0) {
                /* NOOP tx has only one ZC-ACK cookie, can carry at least one more */
                if (tx->tx_msg.ksm_zc_cookies[1] > cookie) {
                        tx->tx_msg.ksm_zc_cookies[0] = tx->tx_msg.ksm_zc_cookies[1];
                        tx->tx_msg.ksm_zc_cookies[1] = cookie;
                } else {
                        tx->tx_msg.ksm_zc_cookies[0] = cookie;
                }

                if (tx->tx_msg.ksm_zc_cookies[0] - tx->tx_msg.ksm_zc_cookies[1] > 2) {
                        /* not likely to carry more ACKs, skip it to simplify logic */
                        ksocknal_next_tx_carrier(conn);
                }

                return 1;
        }

        /* takes two or more cookies already */

        if (tx->tx_msg.ksm_zc_cookies[0] > tx->tx_msg.ksm_zc_cookies[1]) {
                __u64   tmp = 0;

                /* two separated cookies: (a+2, a) or (a+1, a) */
                LASSERT (tx->tx_msg.ksm_zc_cookies[0] -
                         tx->tx_msg.ksm_zc_cookies[1] <= 2);

                if (tx->tx_msg.ksm_zc_cookies[0] -
                    tx->tx_msg.ksm_zc_cookies[1] == 2) {
                        if (cookie == tx->tx_msg.ksm_zc_cookies[1] + 1)
                                tmp = cookie;
                } else if (cookie == tx->tx_msg.ksm_zc_cookies[1] - 1) {
                        tmp = tx->tx_msg.ksm_zc_cookies[1];
                } else if (cookie == tx->tx_msg.ksm_zc_cookies[0] + 1) {
                        tmp = tx->tx_msg.ksm_zc_cookies[0];
                }

                if (tmp != 0) {
                        /* range of cookies */
                        tx->tx_msg.ksm_zc_cookies[0] = tmp - 1;
                        tx->tx_msg.ksm_zc_cookies[1] = tmp + 1;
                        return 1;
                }

        } else {
                /* ksm_zc_cookies[0] < ksm_zc_cookies[1], it is range of cookies */
                if (cookie >= tx->tx_msg.ksm_zc_cookies[0] &&
                    cookie <= tx->tx_msg.ksm_zc_cookies[1]) {
                        CWARN("%s: duplicated ZC cookie: "LPU64"\n",
                              libcfs_id2str(conn->ksnc_peer->ksnp_id), cookie);
                        return 1; /* XXX: return error in the future */
                }

                if (cookie == tx->tx_msg.ksm_zc_cookies[1] + 1) {
                        tx->tx_msg.ksm_zc_cookies[1] = cookie;
                        return 1;
                }

                if (cookie == tx->tx_msg.ksm_zc_cookies[0] - 1) {
                        tx->tx_msg.ksm_zc_cookies[0] = cookie;
                        return 1;
                }
        }

        /* failed to piggyback ZC-ACK */
        if (tx_ack != NULL) {
                list_add_tail(&tx_ack->tx_list, &conn->ksnc_tx_queue);
                /* the next tx can piggyback at least 1 ACK */
                ksocknal_next_tx_carrier(conn);
        }

        return 0;
}

static int
ksocknal_match_tx(ksock_conn_t *conn, ksock_tx_t *tx, int nonblk)
{
        int nob;

#if SOCKNAL_VERSION_DEBUG
        if (!*ksocknal_tunables.ksnd_typed_conns)
                return SOCKNAL_MATCH_YES;
#endif

        if (tx == NULL || tx->tx_lnetmsg == NULL) {
                /* noop packet */
                nob = offsetof(ksock_msg_t, ksm_u);
        } else {
                nob = tx->tx_lnetmsg->msg_len +
                      ((conn->ksnc_proto == &ksocknal_protocol_v1x) ?
                       sizeof(lnet_hdr_t) : sizeof(ksock_msg_t));
        }

        /* default checking for typed connection */
        switch (conn->ksnc_type) {
        default:
                CERROR("ksnc_type bad: %u\n", conn->ksnc_type);
                LBUG();
        case SOCKLND_CONN_ANY:
                return SOCKNAL_MATCH_YES;

        case SOCKLND_CONN_BULK_IN:
                return SOCKNAL_MATCH_MAY;

        case SOCKLND_CONN_BULK_OUT:
                if (nob < *ksocknal_tunables.ksnd_min_bulk)
                        return SOCKNAL_MATCH_MAY;
                else
                        return SOCKNAL_MATCH_YES;

        case SOCKLND_CONN_CONTROL:
                if (nob >= *ksocknal_tunables.ksnd_min_bulk)
                        return SOCKNAL_MATCH_MAY;
                else
                        return SOCKNAL_MATCH_YES;
        }
}

static int
ksocknal_match_tx_v3(ksock_conn_t *conn, ksock_tx_t *tx, int nonblk)
{
        int nob;

        if (tx == NULL || tx->tx_lnetmsg == NULL)
                nob = offsetof(ksock_msg_t, ksm_u);
        else
                nob = tx->tx_lnetmsg->msg_len + sizeof(ksock_msg_t);

        switch (conn->ksnc_type) {
        default:
                CERROR("ksnc_type bad: %u\n", conn->ksnc_type);
                LBUG();
        case SOCKLND_CONN_ANY:
                return SOCKNAL_MATCH_NO;

        case SOCKLND_CONN_ACK:
                if (nonblk)
                        return SOCKNAL_MATCH_YES;
                else if (tx == NULL || tx->tx_lnetmsg == NULL)
                        return SOCKNAL_MATCH_MAY;
                else
                        return SOCKNAL_MATCH_NO;

        case SOCKLND_CONN_BULK_OUT:
                if (nonblk)
                        return SOCKNAL_MATCH_NO;
                else if (nob < *ksocknal_tunables.ksnd_min_bulk)
                        return SOCKNAL_MATCH_MAY;
                else
                        return SOCKNAL_MATCH_YES;

        case SOCKLND_CONN_CONTROL:
                if (nonblk)
                        return SOCKNAL_MATCH_NO;
                else if (nob >= *ksocknal_tunables.ksnd_min_bulk)
                        return SOCKNAL_MATCH_MAY;
                else
                        return SOCKNAL_MATCH_YES;
        }
}

/* (Sink) handle incoming ZC request from sender */
static int
ksocknal_handle_zcreq(ksock_conn_t *c, __u64 cookie, int remote)
{
        ksock_peer_t   *peer = c->ksnc_peer;
        ksock_conn_t   *conn;
        ksock_tx_t     *tx;
        int          rc;

        read_lock(&ksocknal_data.ksnd_global_lock);

        conn = ksocknal_find_conn_locked(peer, NULL, !!remote);
        if (conn != NULL) {
                ksock_sched_t *sched = conn->ksnc_scheduler;

                LASSERT(conn->ksnc_proto->pro_queue_tx_zcack != NULL);

                spin_lock_bh(&sched->kss_lock);

                rc = conn->ksnc_proto->pro_queue_tx_zcack(conn, NULL, cookie);

                spin_unlock_bh(&sched->kss_lock);

                if (rc) { /* piggybacked */
                        read_unlock(&ksocknal_data.ksnd_global_lock);
                        return 0;
                }
        }

        read_unlock(&ksocknal_data.ksnd_global_lock);

        /* ACK connection is not ready, or can't piggyback the ACK */
        tx = ksocknal_alloc_tx_noop(cookie, !!remote);
        if (tx == NULL)
                return -ENOMEM;

        if ((rc = ksocknal_launch_packet(peer->ksnp_ni, tx, peer->ksnp_id)) == 0)
                return 0;

        ksocknal_free_tx(tx);
        return rc;
}

/* (Sender) handle ZC_ACK from sink */
static int
ksocknal_handle_zcack(ksock_conn_t *conn, __u64 cookie1, __u64 cookie2)
{
        ksock_peer_t      *peer = conn->ksnc_peer;
        ksock_tx_t      *tx;
        ksock_tx_t      *tmp;
        LIST_HEAD     (zlist);
        int             count;

        if (cookie1 == 0)
                cookie1 = cookie2;

        count = (cookie1 > cookie2) ? 2 : (cookie2 - cookie1 + 1);

        if (cookie2 == SOCKNAL_KEEPALIVE_PING &&
            conn->ksnc_proto == &ksocknal_protocol_v3x) {
                /* keepalive PING for V3.x, just ignore it */
                return count == 1 ? 0 : -EPROTO;
        }

        spin_lock(&peer->ksnp_lock);

        list_for_each_entry_safe(tx, tmp,
                                     &peer->ksnp_zc_req_list, tx_zc_list) {
                __u64 c = tx->tx_msg.ksm_zc_cookies[0];

                if (c == cookie1 || c == cookie2 || (cookie1 < c && c < cookie2)) {
                        tx->tx_msg.ksm_zc_cookies[0] = 0;
                        list_del(&tx->tx_zc_list);
                        list_add(&tx->tx_zc_list, &zlist);

                        if (--count == 0)
                                break;
                }
        }

        spin_unlock(&peer->ksnp_lock);

        while (!list_empty(&zlist)) {
                tx = list_entry(zlist.next, ksock_tx_t, tx_zc_list);
                list_del(&tx->tx_zc_list);
                ksocknal_tx_decref(tx);
        }

        return count == 0 ? 0 : -EPROTO;
}

static int
ksocknal_send_hello_v1 (ksock_conn_t *conn, ksock_hello_msg_t *hello)
{
        socket_t        *sock = conn->ksnc_sock;
        lnet_hdr_t        *hdr;
        lnet_magicversion_t *hmv;
        int               rc;
        int               i;

        CLASSERT(sizeof(lnet_magicversion_t) == offsetof(lnet_hdr_t, src_nid));

        LIBCFS_ALLOC(hdr, sizeof(*hdr));
        if (hdr == NULL) {
                CERROR("Can't allocate lnet_hdr_t\n");
                return -ENOMEM;
        }

        hmv = (lnet_magicversion_t *)&hdr->dest_nid;

        /* Re-organize V2.x message header to V1.x (lnet_hdr_t)
         * header and send out */
        hmv->magic       = cpu_to_le32 (LNET_PROTO_TCP_MAGIC);
        hmv->version_major = cpu_to_le16 (KSOCK_PROTO_V1_MAJOR);
        hmv->version_minor = cpu_to_le16 (KSOCK_PROTO_V1_MINOR);

        if (the_lnet.ln_testprotocompat != 0) {
                /* single-shot proto check */
                LNET_LOCK();
                if ((the_lnet.ln_testprotocompat & 1) != 0) {
                        hmv->version_major++;   /* just different! */
                        the_lnet.ln_testprotocompat &= ~1;
                }
                if ((the_lnet.ln_testprotocompat & 2) != 0) {
                        hmv->magic = LNET_PROTO_MAGIC;
                        the_lnet.ln_testprotocompat &= ~2;
                }
                LNET_UNLOCK();
        }

        hdr->src_nid    = cpu_to_le64 (hello->kshm_src_nid);
        hdr->src_pid    = cpu_to_le32 (hello->kshm_src_pid);
        hdr->type          = cpu_to_le32 (LNET_MSG_HELLO);
        hdr->payload_length = cpu_to_le32 (hello->kshm_nips * sizeof(__u32));
        hdr->msg.hello.type = cpu_to_le32 (hello->kshm_ctype);
        hdr->msg.hello.incarnation = cpu_to_le64 (hello->kshm_src_incarnation);

        rc = libcfs_sock_write(sock, hdr, sizeof(*hdr),lnet_acceptor_timeout());

        if (rc != 0) {
                CNETERR("Error %d sending HELLO hdr to %pI4h/%d\n",
                        rc, &conn->ksnc_ipaddr, conn->ksnc_port);
                goto out;
        }

        if (hello->kshm_nips == 0)
                goto out;

        for (i = 0; i < (int) hello->kshm_nips; i++) {
                hello->kshm_ips[i] = __cpu_to_le32 (hello->kshm_ips[i]);
        }

        rc = libcfs_sock_write(sock, hello->kshm_ips,
                               hello->kshm_nips * sizeof(__u32),
                               lnet_acceptor_timeout());
        if (rc != 0) {
                CNETERR("Error %d sending HELLO payload (%d)"
                        " to %pI4h/%d\n", rc, hello->kshm_nips,
                        &conn->ksnc_ipaddr, conn->ksnc_port);
        }
out:
        LIBCFS_FREE(hdr, sizeof(*hdr));

        return rc;
}

static int
ksocknal_send_hello_v2 (ksock_conn_t *conn, ksock_hello_msg_t *hello)
{
        socket_t   *sock = conn->ksnc_sock;
        int          rc;

        hello->kshm_magic   = LNET_PROTO_MAGIC;
        hello->kshm_version = conn->ksnc_proto->pro_version;

        if (the_lnet.ln_testprotocompat != 0) {
                /* single-shot proto check */
                LNET_LOCK();
                if ((the_lnet.ln_testprotocompat & 1) != 0) {
                        hello->kshm_version++;   /* just different! */
                        the_lnet.ln_testprotocompat &= ~1;
                }
                LNET_UNLOCK();
        }

        rc = libcfs_sock_write(sock, hello, offsetof(ksock_hello_msg_t, kshm_ips),
                               lnet_acceptor_timeout());

        if (rc != 0) {
                CNETERR("Error %d sending HELLO hdr to %pI4h/%d\n",
                        rc, &conn->ksnc_ipaddr, conn->ksnc_port);
                return rc;
        }

        if (hello->kshm_nips == 0)
                return 0;

        rc = libcfs_sock_write(sock, hello->kshm_ips,
                               hello->kshm_nips * sizeof(__u32),
                               lnet_acceptor_timeout());
        if (rc != 0) {
                CNETERR("Error %d sending HELLO payload (%d)"
                        " to %pI4h/%d\n", rc, hello->kshm_nips,
                        &conn->ksnc_ipaddr, conn->ksnc_port);
        }

        return rc;
}

static int
ksocknal_recv_hello_v1(ksock_conn_t *conn, ksock_hello_msg_t *hello,int timeout)
{
        socket_t        *sock = conn->ksnc_sock;
        lnet_hdr_t        *hdr;
        int               rc;
        int               i;

        LIBCFS_ALLOC(hdr, sizeof(*hdr));
        if (hdr == NULL) {
                CERROR("Can't allocate lnet_hdr_t\n");
                return -ENOMEM;
        }

        rc = libcfs_sock_read(sock, &hdr->src_nid,
                              sizeof (*hdr) - offsetof (lnet_hdr_t, src_nid),
                              timeout);
        if (rc != 0) {
                CERROR("Error %d reading rest of HELLO hdr from %pI4h\n",
                        rc, &conn->ksnc_ipaddr);
                LASSERT (rc < 0 && rc != -EALREADY);
                goto out;
        }

        /* ...and check we got what we expected */
        if (hdr->type != cpu_to_le32 (LNET_MSG_HELLO)) {
                CERROR("Expecting a HELLO hdr,"
                        " but got type %d from %pI4h\n",
                        le32_to_cpu (hdr->type),
                        &conn->ksnc_ipaddr);
                rc = -EPROTO;
                goto out;
        }

        hello->kshm_src_nid      = le64_to_cpu (hdr->src_nid);
        hello->kshm_src_pid      = le32_to_cpu (hdr->src_pid);
        hello->kshm_src_incarnation = le64_to_cpu (hdr->msg.hello.incarnation);
        hello->kshm_ctype          = le32_to_cpu (hdr->msg.hello.type);
        hello->kshm_nips            = le32_to_cpu (hdr->payload_length) /
                                         sizeof (__u32);

        if (hello->kshm_nips > LNET_MAX_INTERFACES) {
                CERROR("Bad nips %d from ip %pI4h\n",
                       hello->kshm_nips, &conn->ksnc_ipaddr);
                rc = -EPROTO;
                goto out;
        }

        if (hello->kshm_nips == 0)
                goto out;

        rc = libcfs_sock_read(sock, hello->kshm_ips,
                              hello->kshm_nips * sizeof(__u32), timeout);
        if (rc != 0) {
                CERROR("Error %d reading IPs from ip %pI4h\n",
                        rc, &conn->ksnc_ipaddr);
                LASSERT(rc < 0 && rc != -EALREADY);
                goto out;
        }

        for (i = 0; i < (int) hello->kshm_nips; i++) {
                hello->kshm_ips[i] = __le32_to_cpu(hello->kshm_ips[i]);

                if (hello->kshm_ips[i] == 0) {
                        CERROR("Zero IP[%d] from ip %pI4h\n",
                               i, &conn->ksnc_ipaddr);
                        rc = -EPROTO;
                        break;
                }
        }
out:
        LIBCFS_FREE(hdr, sizeof(*hdr));

        return rc;
}

static int
ksocknal_recv_hello_v2 (ksock_conn_t *conn, ksock_hello_msg_t *hello, int timeout)
{
        socket_t      *sock = conn->ksnc_sock;
        int             rc;
        int             i;

        if (hello->kshm_magic == LNET_PROTO_MAGIC)
                conn->ksnc_flip = 0;
        else
                conn->ksnc_flip = 1;

        rc = libcfs_sock_read(sock, &hello->kshm_src_nid,
                              offsetof(ksock_hello_msg_t, kshm_ips) -
                                       offsetof(ksock_hello_msg_t, kshm_src_nid),
                              timeout);
        if (rc != 0) {
                CERROR("Error %d reading HELLO from %pI4h\n",
                        rc, &conn->ksnc_ipaddr);
                LASSERT(rc < 0 && rc != -EALREADY);
                return rc;
        }

        if (conn->ksnc_flip) {
                __swab32s(&hello->kshm_src_pid);
                __swab64s(&hello->kshm_src_nid);
                __swab32s(&hello->kshm_dst_pid);
                __swab64s(&hello->kshm_dst_nid);
                __swab64s(&hello->kshm_src_incarnation);
                __swab64s(&hello->kshm_dst_incarnation);
                __swab32s(&hello->kshm_ctype);
                __swab32s(&hello->kshm_nips);
        }

        if (hello->kshm_nips > LNET_MAX_INTERFACES) {
                CERROR("Bad nips %d from ip %pI4h\n",
                       hello->kshm_nips, &conn->ksnc_ipaddr);
                return -EPROTO;
        }

        if (hello->kshm_nips == 0)
                return 0;

        rc = libcfs_sock_read(sock, hello->kshm_ips,
                              hello->kshm_nips * sizeof(__u32), timeout);
        if (rc != 0) {
                CERROR("Error %d reading IPs from ip %pI4h\n",
                        rc, &conn->ksnc_ipaddr);
                LASSERT(rc < 0 && rc != -EALREADY);
                return rc;
        }

        for (i = 0; i < (int) hello->kshm_nips; i++) {
                if (conn->ksnc_flip)
                        __swab32s(&hello->kshm_ips[i]);

                if (hello->kshm_ips[i] == 0) {
                        CERROR("Zero IP[%d] from ip %pI4h\n",
                               i, &conn->ksnc_ipaddr);
                        return -EPROTO;
                }
        }

        return 0;
}

static void
ksocknal_pack_msg_v1(ksock_tx_t *tx)
{
        /* V1.x has no KSOCK_MSG_NOOP */
        LASSERT(tx->tx_msg.ksm_type != KSOCK_MSG_NOOP);
        LASSERT(tx->tx_lnetmsg != NULL);

        tx->tx_iov[0].iov_base = (void *)&tx->tx_lnetmsg->msg_hdr;
        tx->tx_iov[0].iov_len  = sizeof(lnet_hdr_t);

        tx->tx_resid = tx->tx_nob = tx->tx_lnetmsg->msg_len + sizeof(lnet_hdr_t);
}

static void
ksocknal_pack_msg_v2(ksock_tx_t *tx)
{
        tx->tx_iov[0].iov_base = (void *)&tx->tx_msg;

        if (tx->tx_lnetmsg != NULL) {
                LASSERT(tx->tx_msg.ksm_type != KSOCK_MSG_NOOP);

                tx->tx_msg.ksm_u.lnetmsg.ksnm_hdr = tx->tx_lnetmsg->msg_hdr;
                tx->tx_iov[0].iov_len = sizeof(ksock_msg_t);
                tx->tx_resid = tx->tx_nob = sizeof(ksock_msg_t) + tx->tx_lnetmsg->msg_len;
        } else {
                LASSERT(tx->tx_msg.ksm_type == KSOCK_MSG_NOOP);

                tx->tx_iov[0].iov_len = offsetof(ksock_msg_t, ksm_u.lnetmsg.ksnm_hdr);
                tx->tx_resid = tx->tx_nob = offsetof(ksock_msg_t,  ksm_u.lnetmsg.ksnm_hdr);
        }
        /* Don't checksum before start sending, because packet can be piggybacked with ACK */
}

static void
ksocknal_unpack_msg_v1(ksock_msg_t *msg)
{
        msg->ksm_csum      = 0;
        msg->ksm_type      = KSOCK_MSG_LNET;
        msg->ksm_zc_cookies[0]  = msg->ksm_zc_cookies[1]  = 0;
}

static void
ksocknal_unpack_msg_v2(ksock_msg_t *msg)
{
        return;  /* Do nothing */
}

ksock_proto_t  ksocknal_protocol_v1x =
{
        .pro_version        = KSOCK_PROTO_V1,
        .pro_send_hello  = ksocknal_send_hello_v1,
        .pro_recv_hello  = ksocknal_recv_hello_v1,
        .pro_pack              = ksocknal_pack_msg_v1,
        .pro_unpack          = ksocknal_unpack_msg_v1,
        .pro_queue_tx_msg       = ksocknal_queue_tx_msg_v1,
        .pro_handle_zcreq       = NULL,
        .pro_handle_zcack       = NULL,
        .pro_queue_tx_zcack     = NULL,
        .pro_match_tx      = ksocknal_match_tx
};

ksock_proto_t  ksocknal_protocol_v2x =
{
        .pro_version        = KSOCK_PROTO_V2,
        .pro_send_hello  = ksocknal_send_hello_v2,
        .pro_recv_hello  = ksocknal_recv_hello_v2,
        .pro_pack              = ksocknal_pack_msg_v2,
        .pro_unpack          = ksocknal_unpack_msg_v2,
        .pro_queue_tx_msg       = ksocknal_queue_tx_msg_v2,
        .pro_queue_tx_zcack     = ksocknal_queue_tx_zcack_v2,
        .pro_handle_zcreq       = ksocknal_handle_zcreq,
        .pro_handle_zcack       = ksocknal_handle_zcack,
        .pro_match_tx      = ksocknal_match_tx
};

ksock_proto_t  ksocknal_protocol_v3x =
{
        .pro_version        = KSOCK_PROTO_V3,
        .pro_send_hello  = ksocknal_send_hello_v2,
        .pro_recv_hello  = ksocknal_recv_hello_v2,
        .pro_pack              = ksocknal_pack_msg_v2,
        .pro_unpack          = ksocknal_unpack_msg_v2,
        .pro_queue_tx_msg       = ksocknal_queue_tx_msg_v2,
        .pro_queue_tx_zcack     = ksocknal_queue_tx_zcack_v3,
        .pro_handle_zcreq       = ksocknal_handle_zcreq,
        .pro_handle_zcack       = ksocknal_handle_zcack,
        .pro_match_tx      = ksocknal_match_tx_v3
};