/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

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

#include <sys/types.h>
#include <sys/strlog.h>
#include <sys/policy.h>
#include <sys/strsun.h>
#include <sys/squeue_impl.h>
#include <sys/squeue.h>

#include <inet/common.h>
#include <inet/ip.h>
#include <inet/tcp.h>
#include <inet/tcp_impl.h>

/* Control whether TCP can enter defensive mode when under memory pressure. */
static boolean_t tcp_do_reclaim = B_TRUE;

/*
 * Routines related to the TCP_IOC_ABORT_CONN ioctl command.
 *
 * TCP_IOC_ABORT_CONN is a non-transparent ioctl command used for aborting
 * TCP connections. To invoke this ioctl, a tcp_ioc_abort_conn_t structure
 * (defined in tcp.h) needs to be filled in and passed into the kernel
 * via an I_STR ioctl command (see streamio(4I)). The tcp_ioc_abort_conn_t
 * structure contains the four-tuple of a TCP connection and a range of TCP
 * states (specified by ac_start and ac_end). The use of wildcard addresses
 * and ports is allowed. Connections with a matching four tuple and a state
 * within the specified range will be aborted. The valid states for the
 * ac_start and ac_end fields are in the range TCPS_SYN_SENT to TCPS_TIME_WAIT,
 * inclusive.
 *
 * An application which has its connection aborted by this ioctl will receive
 * an error that is dependent on the connection state at the time of the abort.
 * If the connection state is < TCPS_TIME_WAIT, an application should behave as
 * though a RST packet has been received.  If the connection state is equal to
 * TCPS_TIME_WAIT, the 2MSL timeout will immediately be canceled by the kernel
 * and all resources associated with the connection will be freed.
 */
static mblk_t   *tcp_ioctl_abort_build_msg(tcp_ioc_abort_conn_t *, tcp_t *);
static void     tcp_ioctl_abort_dump(tcp_ioc_abort_conn_t *);
static void     tcp_ioctl_abort_handler(void *arg, mblk_t *mp, void *arg2,
    ip_recv_attr_t *dummy);
static int      tcp_ioctl_abort(tcp_ioc_abort_conn_t *, tcp_stack_t *tcps);
void    tcp_ioctl_abort_conn(queue_t *, mblk_t *);
static int      tcp_ioctl_abort_bucket(tcp_ioc_abort_conn_t *, int, int *,
    boolean_t, tcp_stack_t *);

/*
 * Macros used for accessing the different types of sockaddr
 * structures inside a tcp_ioc_abort_conn_t.
 */
#define TCP_AC_V4LADDR(acp) ((sin_t *)&(acp)->ac_local)
#define TCP_AC_V4RADDR(acp) ((sin_t *)&(acp)->ac_remote)
#define TCP_AC_V4LOCAL(acp) (TCP_AC_V4LADDR(acp)->sin_addr.s_addr)
#define TCP_AC_V4REMOTE(acp) (TCP_AC_V4RADDR(acp)->sin_addr.s_addr)
#define TCP_AC_V4LPORT(acp) (TCP_AC_V4LADDR(acp)->sin_port)
#define TCP_AC_V4RPORT(acp) (TCP_AC_V4RADDR(acp)->sin_port)
#define TCP_AC_V6LADDR(acp) ((sin6_t *)&(acp)->ac_local)
#define TCP_AC_V6RADDR(acp) ((sin6_t *)&(acp)->ac_remote)
#define TCP_AC_V6LOCAL(acp) (TCP_AC_V6LADDR(acp)->sin6_addr)
#define TCP_AC_V6REMOTE(acp) (TCP_AC_V6RADDR(acp)->sin6_addr)
#define TCP_AC_V6LPORT(acp) (TCP_AC_V6LADDR(acp)->sin6_port)
#define TCP_AC_V6RPORT(acp) (TCP_AC_V6RADDR(acp)->sin6_port)

/*
 * Return the correct error code to mimic the behavior
 * of a connection reset.
 */
#define TCP_AC_GET_ERRCODE(state, err) {        \
                switch ((state)) {              \
                case TCPS_SYN_SENT:             \
                case TCPS_SYN_RCVD:             \
                        (err) = ECONNREFUSED;   \
                        break;                  \
                case TCPS_ESTABLISHED:          \
                case TCPS_FIN_WAIT_1:           \
                case TCPS_FIN_WAIT_2:           \
                case TCPS_CLOSE_WAIT:           \
                        (err) = ECONNRESET;     \
                        break;                  \
                case TCPS_CLOSING:              \
                case TCPS_LAST_ACK:             \
                case TCPS_TIME_WAIT:            \
                        (err) = 0;              \
                        break;                  \
                default:                        \
                        (err) = ENXIO;          \
                }                               \
        }

/*
 * Check if a tcp structure matches the info in acp.
 */
#define TCP_AC_ADDR_MATCH(acp, connp, tcp)                      \
        (((acp)->ac_local.ss_family == AF_INET) ?               \
        ((TCP_AC_V4LOCAL((acp)) == INADDR_ANY ||                \
        TCP_AC_V4LOCAL((acp)) == (connp)->conn_laddr_v4) &&     \
        (TCP_AC_V4REMOTE((acp)) == INADDR_ANY ||                \
        TCP_AC_V4REMOTE((acp)) == (connp)->conn_faddr_v4) &&    \
        (TCP_AC_V4LPORT((acp)) == 0 ||                          \
        TCP_AC_V4LPORT((acp)) == (connp)->conn_lport) &&        \
        (TCP_AC_V4RPORT((acp)) == 0 ||                          \
        TCP_AC_V4RPORT((acp)) == (connp)->conn_fport) &&        \
        (acp)->ac_start <= (tcp)->tcp_state &&                  \
        (acp)->ac_end >= (tcp)->tcp_state) :                    \
        ((IN6_IS_ADDR_UNSPECIFIED(&TCP_AC_V6LOCAL((acp))) ||    \
        IN6_ARE_ADDR_EQUAL(&TCP_AC_V6LOCAL((acp)),              \
        &(connp)->conn_laddr_v6)) &&                            \
        (IN6_IS_ADDR_UNSPECIFIED(&TCP_AC_V6REMOTE((acp))) ||    \
        IN6_ARE_ADDR_EQUAL(&TCP_AC_V6REMOTE((acp)),             \
        &(connp)->conn_faddr_v6)) &&                            \
        (TCP_AC_V6LPORT((acp)) == 0 ||                          \
        TCP_AC_V6LPORT((acp)) == (connp)->conn_lport) &&        \
        (TCP_AC_V6RPORT((acp)) == 0 ||                          \
        TCP_AC_V6RPORT((acp)) == (connp)->conn_fport) &&        \
        (acp)->ac_start <= (tcp)->tcp_state &&                  \
        (acp)->ac_end >= (tcp)->tcp_state))

#define TCP_AC_MATCH(acp, connp, tcp)                           \
        (((acp)->ac_zoneid == ALL_ZONES ||                      \
        (acp)->ac_zoneid == (connp)->conn_zoneid) ?             \
        TCP_AC_ADDR_MATCH(acp, connp, tcp) : 0)

/*
 * Build a message containing a tcp_ioc_abort_conn_t structure
 * which is filled in with information from acp and tp.
 */
static mblk_t *
tcp_ioctl_abort_build_msg(tcp_ioc_abort_conn_t *acp, tcp_t *tp)
{
        mblk_t *mp;
        tcp_ioc_abort_conn_t *tacp;

        mp = allocb(sizeof (uint32_t) + sizeof (*acp), BPRI_LO);
        if (mp == NULL)
                return (NULL);

        *((uint32_t *)mp->b_rptr) = TCP_IOC_ABORT_CONN;
        tacp = (tcp_ioc_abort_conn_t *)((uchar_t *)mp->b_rptr +
            sizeof (uint32_t));

        tacp->ac_start = acp->ac_start;
        tacp->ac_end = acp->ac_end;
        tacp->ac_zoneid = acp->ac_zoneid;

        if (acp->ac_local.ss_family == AF_INET) {
                tacp->ac_local.ss_family = AF_INET;
                tacp->ac_remote.ss_family = AF_INET;
                TCP_AC_V4LOCAL(tacp) = tp->tcp_connp->conn_laddr_v4;
                TCP_AC_V4REMOTE(tacp) = tp->tcp_connp->conn_faddr_v4;
                TCP_AC_V4LPORT(tacp) = tp->tcp_connp->conn_lport;
                TCP_AC_V4RPORT(tacp) = tp->tcp_connp->conn_fport;
        } else {
                tacp->ac_local.ss_family = AF_INET6;
                tacp->ac_remote.ss_family = AF_INET6;
                TCP_AC_V6LOCAL(tacp) = tp->tcp_connp->conn_laddr_v6;
                TCP_AC_V6REMOTE(tacp) = tp->tcp_connp->conn_faddr_v6;
                TCP_AC_V6LPORT(tacp) = tp->tcp_connp->conn_lport;
                TCP_AC_V6RPORT(tacp) = tp->tcp_connp->conn_fport;
        }
        mp->b_wptr = (uchar_t *)mp->b_rptr + sizeof (uint32_t) + sizeof (*acp);
        return (mp);
}

/*
 * Print a tcp_ioc_abort_conn_t structure.
 */
static void
tcp_ioctl_abort_dump(tcp_ioc_abort_conn_t *acp)
{
        char lbuf[128];
        char rbuf[128];
        sa_family_t af;
        in_port_t lport, rport;
        ushort_t logflags;

        af = acp->ac_local.ss_family;

        if (af == AF_INET) {
                (void) inet_ntop(af, (const void *)&TCP_AC_V4LOCAL(acp),
                    lbuf, 128);
                (void) inet_ntop(af, (const void *)&TCP_AC_V4REMOTE(acp),
                    rbuf, 128);
                lport = ntohs(TCP_AC_V4LPORT(acp));
                rport = ntohs(TCP_AC_V4RPORT(acp));
        } else {
                (void) inet_ntop(af, (const void *)&TCP_AC_V6LOCAL(acp),
                    lbuf, 128);
                (void) inet_ntop(af, (const void *)&TCP_AC_V6REMOTE(acp),
                    rbuf, 128);
                lport = ntohs(TCP_AC_V6LPORT(acp));
                rport = ntohs(TCP_AC_V6RPORT(acp));
        }

        logflags = SL_TRACE | SL_NOTE;
        /*
         * Don't print this message to the console if the operation was done
         * to a non-global zone.
         */
        if (acp->ac_zoneid == GLOBAL_ZONEID || acp->ac_zoneid == ALL_ZONES)
                logflags |= SL_CONSOLE;
        (void) strlog(TCP_MOD_ID, 0, 1, logflags,
            "TCP_IOC_ABORT_CONN: local = %s:%d, remote = %s:%d, "
            "start = %d, end = %d\n", lbuf, lport, rbuf, rport,
            acp->ac_start, acp->ac_end);
}

/*
 * Called using SQ_FILL when a message built using
 * tcp_ioctl_abort_build_msg is put into a queue.
 * Note that when we get here there is no wildcard in acp any more.
 */
/* ARGSUSED2 */
static void
tcp_ioctl_abort_handler(void *arg, mblk_t *mp, void *arg2,
    ip_recv_attr_t *dummy)
{
        conn_t                  *connp = (conn_t *)arg;
        tcp_t                   *tcp = connp->conn_tcp;
        tcp_ioc_abort_conn_t    *acp;

        /*
         * Don't accept any input on a closed tcp as this TCP logically does
         * not exist on the system. Don't proceed further with this TCP.
         * For eg. this packet could trigger another close of this tcp
         * which would be disastrous for tcp_refcnt. tcp_close_detached /
         * tcp_clean_death / tcp_closei_local must be called at most once
         * on a TCP.
         */
        if (tcp->tcp_state == TCPS_CLOSED ||
            tcp->tcp_state == TCPS_BOUND) {
                freemsg(mp);
                return;
        }

        acp = (tcp_ioc_abort_conn_t *)(mp->b_rptr + sizeof (uint32_t));
        if (tcp->tcp_state <= acp->ac_end) {
                /*
                 * If we get here, we are already on the correct
                 * squeue. This ioctl follows the following path
                 * tcp_wput -> tcp_wput_ioctl -> tcp_ioctl_abort_conn
                 * ->tcp_ioctl_abort->squeue_enter (if on a
                 * different squeue)
                 */
                int errcode;

                TCP_AC_GET_ERRCODE(tcp->tcp_state, errcode);
                (void) tcp_clean_death(tcp, errcode);
        }
        freemsg(mp);
}

/*
 * Abort all matching connections on a hash chain.
 */
static int
tcp_ioctl_abort_bucket(tcp_ioc_abort_conn_t *acp, int index, int *count,
    boolean_t exact, tcp_stack_t *tcps)
{
        int nmatch, err = 0;
        tcp_t *tcp;
        MBLKP mp, last, listhead = NULL;
        conn_t  *tconnp;
        connf_t *connfp;
        ip_stack_t *ipst = tcps->tcps_netstack->netstack_ip;

        connfp = &ipst->ips_ipcl_conn_fanout[index];

startover:
        nmatch = 0;
        last = NULL;

        mutex_enter(&connfp->connf_lock);
        for (tconnp = connfp->connf_head; tconnp != NULL;
            tconnp = tconnp->conn_next) {
                tcp = tconnp->conn_tcp;
                /*
                 * We are missing a check on sin6_scope_id for linklocals here,
                 * but current usage is just for aborting based on zoneid
                 * for shared-IP zones.
                 */
                if (TCP_AC_MATCH(acp, tconnp, tcp)) {
                        CONN_INC_REF(tconnp);
                        mp = tcp_ioctl_abort_build_msg(acp, tcp);
                        if (mp == NULL) {
                                err = ENOMEM;
                                CONN_DEC_REF(tconnp);
                                break;
                        }
                        mp->b_prev = (mblk_t *)tcp;

                        if (listhead == NULL) {
                                listhead = mp;
                                last = mp;
                        } else {
                                last->b_next = mp;
                                last = mp;
                        }
                        nmatch++;
                        if (exact)
                                break;
                }

                /* Avoid holding lock for too long. */
                if (nmatch >= 500)
                        break;
        }
        mutex_exit(&connfp->connf_lock);

        /* Pass mp into the correct tcp */
        while ((mp = listhead) != NULL) {
                listhead = listhead->b_next;
                tcp = (tcp_t *)mp->b_prev;
                mp->b_next = mp->b_prev = NULL;
                SQUEUE_ENTER_ONE(tcp->tcp_connp->conn_sqp, mp,
                    tcp_ioctl_abort_handler, tcp->tcp_connp, NULL,
                    SQ_FILL, SQTAG_TCP_ABORT_BUCKET);
        }

        *count += nmatch;
        if (nmatch >= 500 && err == 0)
                goto startover;
        return (err);
}

/*
 * Abort all connections that matches the attributes specified in acp.
 */
static int
tcp_ioctl_abort(tcp_ioc_abort_conn_t *acp, tcp_stack_t *tcps)
{
        sa_family_t af;
        uint32_t  ports;
        uint16_t *pports;
        int err = 0, count = 0;
        boolean_t exact = B_FALSE; /* set when there is no wildcard */
        int index = -1;
        ushort_t logflags;
        ip_stack_t      *ipst = tcps->tcps_netstack->netstack_ip;

        af = acp->ac_local.ss_family;

        if (af == AF_INET) {
                if (TCP_AC_V4REMOTE(acp) != INADDR_ANY &&
                    TCP_AC_V4LPORT(acp) != 0 && TCP_AC_V4RPORT(acp) != 0) {
                        pports = (uint16_t *)&ports;
                        pports[1] = TCP_AC_V4LPORT(acp);
                        pports[0] = TCP_AC_V4RPORT(acp);
                        exact = (TCP_AC_V4LOCAL(acp) != INADDR_ANY);
                }
        } else {
                if (!IN6_IS_ADDR_UNSPECIFIED(&TCP_AC_V6REMOTE(acp)) &&
                    TCP_AC_V6LPORT(acp) != 0 && TCP_AC_V6RPORT(acp) != 0) {
                        pports = (uint16_t *)&ports;
                        pports[1] = TCP_AC_V6LPORT(acp);
                        pports[0] = TCP_AC_V6RPORT(acp);
                        exact = !IN6_IS_ADDR_UNSPECIFIED(&TCP_AC_V6LOCAL(acp));
                }
        }

        /*
         * For cases where remote addr, local port, and remote port are non-
         * wildcards, tcp_ioctl_abort_bucket will only be called once.
         */
        if (index != -1) {
                err = tcp_ioctl_abort_bucket(acp, index,
                    &count, exact, tcps);
        } else {
                /*
                 * loop through all entries for wildcard case
                 */
                for (index = 0;
                    index < ipst->ips_ipcl_conn_fanout_size;
                    index++) {
                        err = tcp_ioctl_abort_bucket(acp, index,
                            &count, exact, tcps);
                        if (err != 0)
                                break;
                }
        }

        logflags = SL_TRACE | SL_NOTE;
        /*
         * Don't print this message to the console if the operation was done
         * to a non-global zone.
         */
        if (acp->ac_zoneid == GLOBAL_ZONEID || acp->ac_zoneid == ALL_ZONES)
                logflags |= SL_CONSOLE;
        (void) strlog(TCP_MOD_ID, 0, 1, logflags, "TCP_IOC_ABORT_CONN: "
            "aborted %d connection%c\n", count, ((count > 1) ? 's' : ' '));
        if (err == 0 && count == 0)
                err = ENOENT;
        return (err);
}

/*
 * Process the TCP_IOC_ABORT_CONN ioctl request.
 */
void
tcp_ioctl_abort_conn(queue_t *q, mblk_t *mp)
{
        int     err;
        IOCP    iocp;
        MBLKP   mp1;
        sa_family_t laf, raf;
        tcp_ioc_abort_conn_t *acp;
        zone_t          *zptr;
        conn_t          *connp = Q_TO_CONN(q);
        zoneid_t        zoneid = connp->conn_zoneid;
        tcp_t           *tcp = connp->conn_tcp;
        tcp_stack_t     *tcps = tcp->tcp_tcps;

        iocp = (IOCP)mp->b_rptr;

        if ((mp1 = mp->b_cont) == NULL ||
            iocp->ioc_count != sizeof (tcp_ioc_abort_conn_t)) {
                err = EINVAL;
                goto out;
        }

        /* check permissions */
        if (secpolicy_ip_config(iocp->ioc_cr, B_FALSE) != 0) {
                err = EPERM;
                goto out;
        }

        if (mp1->b_cont != NULL) {
                freemsg(mp1->b_cont);
                mp1->b_cont = NULL;
        }

        acp = (tcp_ioc_abort_conn_t *)mp1->b_rptr;
        laf = acp->ac_local.ss_family;
        raf = acp->ac_remote.ss_family;

        /* check that a zone with the supplied zoneid exists */
        if (acp->ac_zoneid != GLOBAL_ZONEID && acp->ac_zoneid != ALL_ZONES) {
                zptr = zone_find_by_id(zoneid);
                if (zptr != NULL) {
                        zone_rele(zptr);
                } else {
                        err = EINVAL;
                        goto out;
                }
        }

        /*
         * For exclusive stacks we set the zoneid to zero
         * to make TCP operate as if in the global zone.
         */
        if (tcps->tcps_netstack->netstack_stackid != GLOBAL_NETSTACKID)
                acp->ac_zoneid = GLOBAL_ZONEID;

        if (acp->ac_start < TCPS_SYN_SENT || acp->ac_end > TCPS_TIME_WAIT ||
            acp->ac_start > acp->ac_end || laf != raf ||
            (laf != AF_INET && laf != AF_INET6)) {
                err = EINVAL;
                goto out;
        }

        tcp_ioctl_abort_dump(acp);
        err = tcp_ioctl_abort(acp, tcps);

out:
        if (mp1 != NULL) {
                freemsg(mp1);
                mp->b_cont = NULL;
        }

        if (err != 0)
                miocnak(q, mp, 0, err);
        else
                miocack(q, mp, 0, 0);
}

/*
 * Timeout function to reset the TCP stack variable tcps_reclaim to false.
 */
void
tcp_reclaim_timer(void *arg)
{
        tcp_stack_t *tcps = (tcp_stack_t *)arg;
        int64_t tot_conn = 0;
        int i;
        extern pgcnt_t lotsfree, needfree;

        for (i = 0; i < tcps->tcps_sc_cnt; i++)
                tot_conn += tcps->tcps_sc[i]->tcp_sc_conn_cnt;

        /*
         * This happens only when a stack is going away.  tcps_reclaim_tid
         * should not be reset to 0 when returning in this case.
         */
        mutex_enter(&tcps->tcps_reclaim_lock);
        if (!tcps->tcps_reclaim) {
                mutex_exit(&tcps->tcps_reclaim_lock);
                return;
        }

        if ((freemem >= lotsfree + needfree) || tot_conn < maxusers) {
                tcps->tcps_reclaim = B_FALSE;
                tcps->tcps_reclaim_tid = 0;
        } else {
                /* Stay in defensive mode and restart the timer */
                tcps->tcps_reclaim_tid = timeout(tcp_reclaim_timer,
                    tcps, MSEC_TO_TICK(tcps->tcps_reclaim_period));
        }
        mutex_exit(&tcps->tcps_reclaim_lock);
}

/*
 * Kmem reclaim call back function.  When the system is under memory
 * pressure, we set the TCP stack variable tcps_reclaim to true.  This
 * variable is reset to false after tcps_reclaim_period msecs.  During this
 * period, TCP will be more aggressive in aborting connections not making
 * progress, meaning retransmitting for some time (tcp_early_abort seconds).
 * TCP will also not accept new connection request for those listeners whose
 * q or q0 is not empty.
 */
/* ARGSUSED */
void
tcp_conn_reclaim(void *arg)
{
        netstack_handle_t nh;
        netstack_t *ns;
        tcp_stack_t *tcps;
        extern pgcnt_t lotsfree, needfree;

        if (!tcp_do_reclaim)
                return;

        /*
         * The reclaim function may be called even when the system is not
         * really under memory pressure.
         */
        if (freemem >= lotsfree + needfree)
                return;

        netstack_next_init(&nh);
        while ((ns = netstack_next(&nh)) != NULL) {
                int i;
                int64_t tot_conn = 0;

                /*
                 * During boot time, the first netstack_t is created and
                 * initialized before TCP has registered with the netstack
                 * framework.  If this reclaim function is called before TCP
                 * has finished its initialization, netstack_next() will
                 * return the first netstack_t (since its netstack_flags is
                 * not NSF_UNINIT).  And its netstack_tcp will be NULL.  We
                 * need to catch it.
                 *
                 * All subsequent netstack_t creation will not have this
                 * problem since the initialization is not finished until TCP
                 * has finished its own tcp_stack_t initialization.  Hence
                 * netstack_next() will not return one with NULL netstack_tcp.
                 */
                if ((tcps = ns->netstack_tcp) == NULL) {
                        netstack_rele(ns);
                        continue;
                }

                /*
                 * Even if the system is under memory pressure, the reason may
                 * not be because of TCP activity.  Check the number of
                 * connections in each stack.  If the number exceeds the
                 * threshold (maxusers), turn on defensive mode.
                 */
                for (i = 0; i < tcps->tcps_sc_cnt; i++)
                        tot_conn += tcps->tcps_sc[i]->tcp_sc_conn_cnt;
                if (tot_conn < maxusers) {
                        netstack_rele(ns);
                        continue;
                }

                mutex_enter(&tcps->tcps_reclaim_lock);
                if (!tcps->tcps_reclaim) {
                        tcps->tcps_reclaim = B_TRUE;
                        tcps->tcps_reclaim_tid = timeout(tcp_reclaim_timer,
                            tcps, MSEC_TO_TICK(tcps->tcps_reclaim_period));
                        TCP_STAT(tcps, tcp_reclaim_cnt);
                }
                mutex_exit(&tcps->tcps_reclaim_lock);
                netstack_rele(ns);
        }
        netstack_next_fini(&nh);
}

/*
 * Given a tcp_stack_t and a port (in host byte order), find a listener
 * configuration for that port and return the ratio.
 */
uint32_t
tcp_find_listener_conf(tcp_stack_t *tcps, in_port_t port)
{
        tcp_listener_t  *tl;
        uint32_t ratio = 0;

        mutex_enter(&tcps->tcps_listener_conf_lock);
        for (tl = list_head(&tcps->tcps_listener_conf); tl != NULL;
            tl = list_next(&tcps->tcps_listener_conf, tl)) {
                if (tl->tl_port == port) {
                        ratio = tl->tl_ratio;
                        break;
                }
        }
        mutex_exit(&tcps->tcps_listener_conf_lock);
        return (ratio);
}

/*
 * To remove all listener limit configuration in a tcp_stack_t.
 */
void
tcp_listener_conf_cleanup(tcp_stack_t *tcps)
{
        tcp_listener_t  *tl;

        mutex_enter(&tcps->tcps_listener_conf_lock);
        while ((tl = list_head(&tcps->tcps_listener_conf)) != NULL) {
                list_remove(&tcps->tcps_listener_conf, tl);
                kmem_free(tl, sizeof (tcp_listener_t));
        }
        mutex_destroy(&tcps->tcps_listener_conf_lock);
        list_destroy(&tcps->tcps_listener_conf);
}

/*
 * When a CPU is added, we need to allocate the per CPU stats struct.
 */
void
tcp_stack_cpu_add(tcp_stack_t *tcps, processorid_t cpu_seqid)
{
        int i;

        if (cpu_seqid < tcps->tcps_sc_cnt)
                return;
        for (i = tcps->tcps_sc_cnt; i <= cpu_seqid; i++) {
                ASSERT(tcps->tcps_sc[i] == NULL);
                tcps->tcps_sc[i] = kmem_zalloc(sizeof (tcp_stats_cpu_t),
                    KM_SLEEP);
        }
        membar_producer();
        tcps->tcps_sc_cnt = cpu_seqid + 1;
}

/*
 * Diagnostic routine used to return a string associated with the tcp state.
 * Note that if the caller does not supply a buffer, it will use an internal
 * static string.  This means that if multiple threads call this function at
 * the same time, output can be corrupted...  Note also that this function
 * does not check the size of the supplied buffer.  The caller has to make
 * sure that it is big enough.
 */
char *
tcp_display(tcp_t *tcp, char *sup_buf, char format)
{
        char            buf1[30];
        static char     priv_buf[INET6_ADDRSTRLEN * 2 + 80];
        char            *buf;
        char            *cp;
        in6_addr_t      local, remote;
        char            local_addrbuf[INET6_ADDRSTRLEN];
        char            remote_addrbuf[INET6_ADDRSTRLEN];
        conn_t          *connp;

        if (sup_buf != NULL)
                buf = sup_buf;
        else
                buf = priv_buf;

        if (tcp == NULL)
                return ("NULL_TCP");

        connp = tcp->tcp_connp;
        switch (tcp->tcp_state) {
        case TCPS_CLOSED:
                cp = "TCP_CLOSED";
                break;
        case TCPS_IDLE:
                cp = "TCP_IDLE";
                break;
        case TCPS_BOUND:
                cp = "TCP_BOUND";
                break;
        case TCPS_LISTEN:
                cp = "TCP_LISTEN";
                break;
        case TCPS_SYN_SENT:
                cp = "TCP_SYN_SENT";
                break;
        case TCPS_SYN_RCVD:
                cp = "TCP_SYN_RCVD";
                break;
        case TCPS_ESTABLISHED:
                cp = "TCP_ESTABLISHED";
                break;
        case TCPS_CLOSE_WAIT:
                cp = "TCP_CLOSE_WAIT";
                break;
        case TCPS_FIN_WAIT_1:
                cp = "TCP_FIN_WAIT_1";
                break;
        case TCPS_CLOSING:
                cp = "TCP_CLOSING";
                break;
        case TCPS_LAST_ACK:
                cp = "TCP_LAST_ACK";
                break;
        case TCPS_FIN_WAIT_2:
                cp = "TCP_FIN_WAIT_2";
                break;
        case TCPS_TIME_WAIT:
                cp = "TCP_TIME_WAIT";
                break;
        default:
                (void) mi_sprintf(buf1, "TCPUnkState(%d)", tcp->tcp_state);
                cp = buf1;
                break;
        }
        switch (format) {
        case DISP_ADDR_AND_PORT:
                if (connp->conn_ipversion == IPV4_VERSION) {
                        /*
                         * Note that we use the remote address in the tcp_b
                         * structure.  This means that it will print out
                         * the real destination address, not the next hop's
                         * address if source routing is used.
                         */
                        IN6_IPADDR_TO_V4MAPPED(connp->conn_laddr_v4, &local);
                        IN6_IPADDR_TO_V4MAPPED(connp->conn_faddr_v4, &remote);

                } else {
                        local = connp->conn_laddr_v6;
                        remote = connp->conn_faddr_v6;
                }
                (void) inet_ntop(AF_INET6, &local, local_addrbuf,
                    sizeof (local_addrbuf));
                (void) inet_ntop(AF_INET6, &remote, remote_addrbuf,
                    sizeof (remote_addrbuf));
                (void) mi_sprintf(buf, "[%s.%u, %s.%u] %s",
                    local_addrbuf, ntohs(connp->conn_lport), remote_addrbuf,
                    ntohs(connp->conn_fport), cp);
                break;
        case DISP_PORT_ONLY:
        default:
                (void) mi_sprintf(buf, "[%u, %u] %s",
                    ntohs(connp->conn_lport), ntohs(connp->conn_fport), cp);
                break;
        }

        return (buf);
}