/*
 * 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 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/types.h>
#include <inet/ip.h>
#include <inet/ip_impl.h>
#include <inet/ipclassifier.h>
#include <inet/proto_set.h>
#include <sys/stream.h>
#include <sys/strsubr.h>
#include <sys/strsun.h>
#include <sys/cmn_err.h>
#include <sys/t_kuser.h>
#include <sys/tihdr.h>
#include <sys/pathname.h>
#include <sys/sockio.h>
#include <sys/vmem.h>
#include <sys/disp.h>

int ip_helper_wput(queue_t *q, mblk_t *mp);

static int ip_helper_stream_close(queue_t *, int, cred_t *);

static struct module_info ip_helper_stream_info =  {
        0, "iphelper", IP_MOD_MINPSZ, IP_MOD_MAXPSZ, IP_MOD_HIWAT, IP_MOD_LOWAT
};

static struct qinit ip_helper_stream_rinit = {
        NULL, NULL, NULL, ip_helper_stream_close, NULL,
        &ip_helper_stream_info, NULL
};

static struct qinit ip_helper_stream_winit = {
        ip_helper_wput, ip_wsrv, NULL, NULL, NULL,
        &ip_helper_stream_info, NULL, NULL, NULL, STRUIOT_NONE
};

/*
 * set the q_ptr of the 'q' to the conn_t pointer passed in
 */
static void
ip_helper_share_conn(queue_t *q, mblk_t *mp, cred_t *crp)
{
        conn_t *connp = *((conn_t **)mp->b_cont->b_rptr);

        /*
         * This operation is allowed only on helper streams with kcred
         */

        if (kcred != crp || msgdsize(mp->b_cont) != sizeof (void *)) {
                miocnak(q, mp, 0, EINVAL);
                return;
        }

        connp->conn_helper_info->iphs_minfo = q->q_ptr;
        connp->conn_helper_info->iphs_rq = RD(q);
        connp->conn_helper_info->iphs_wq = WR(q);
        WR(q)->q_ptr = RD(q)->q_ptr = (void *)connp;
        connp->conn_rq = RD(q);
        connp->conn_wq = WR(q);
        miocack(q, mp, 0, 0);
}

int
ip_helper_wput(queue_t *q, mblk_t *mp)
{
        struct iocblk *iocp = (struct iocblk *)mp->b_rptr;
        if (DB_TYPE(mp) == M_IOCTL &&
            iocp->ioc_cmd == SIOCSQPTR) {
                ip_helper_share_conn(q, mp, iocp->ioc_cr);
        } else {
                /* We only handle ioctl related messages here */
                ASSERT(DB_TYPE(mp) != M_DATA);
                ip_wput_nondata(q, mp);
        }
        return (0);
}

/* ARGSUSED3 */
int
ip_helper_stream_setup(queue_t *q, dev_t *devp, int flag, int sflag,
    cred_t *credp, boolean_t isv6)
{
        major_t                 maj;
        ip_helper_minfo_t       *ip_minfop;

        ASSERT((flag & ~(FKLYR)) == IP_HELPER_STR);

        ASSERT(RD(q) == q);

        ip_minfop = kmem_alloc(sizeof (ip_helper_minfo_t), KM_SLEEP);
        ASSERT(ip_minfop != NULL);

        ip_minfop->ip_minfo_dev = 0;
        ip_minfop->ip_minfo_arena = NULL;

        /*
         * Clone the device, allocate minor device number
         */
        if (ip_minor_arena_la != NULL)
                ip_minfop->ip_minfo_dev = inet_minor_alloc(ip_minor_arena_la);

        if (ip_minfop->ip_minfo_dev == 0) {
                /*
                 * numbers in the large arena are exhausted
                 * Try small arena.
                 */
                ip_minfop->ip_minfo_dev = inet_minor_alloc(ip_minor_arena_sa);
                if (ip_minfop->ip_minfo_dev == 0) {
                        kmem_free(ip_minfop, sizeof (ip_helper_minfo_t));
                        return (EBUSY);
                }
                ip_minfop->ip_minfo_arena = ip_minor_arena_sa;
        } else {
                ip_minfop->ip_minfo_arena = ip_minor_arena_la;
        }


        ASSERT(ip_minfop->ip_minfo_dev != 0);
        ASSERT(ip_minfop->ip_minfo_arena != NULL);

        RD(q)->q_ptr = WR(q)->q_ptr = ip_minfop;

        maj = getemajor(*devp);
        *devp = makedevice(maj, (ulong_t)(ip_minfop->ip_minfo_dev));

        q->q_qinfo = &ip_helper_stream_rinit;
        WR(q)->q_qinfo = &ip_helper_stream_winit;
        qprocson(q);
        return (0);
}

/* ARGSUSED */
static int
ip_helper_stream_close(queue_t *q, int flag __unused, cred_t *credp __unused)
{
        ip_helper_minfo_t *ip_minfop;

        qprocsoff(q);
        ip_minfop = (q)->q_ptr;
        inet_minor_free(ip_minfop->ip_minfo_arena,
            ip_minfop->ip_minfo_dev);
        kmem_free(ip_minfop, sizeof (ip_helper_minfo_t));
        RD(q)->q_ptr = NULL;
        WR(q)->q_ptr = NULL;
        return (0);
}

/*
 * Public interface for creating an IP stream with shared conn_t
 * Handles multiple callers in parallel by using conn_lock.
 * Note that we allocate the helper stream without any locks, which means
 * we might need to free it if we had two threads doing this concurrently
 * for the conn_t.
 */
int
ip_create_helper_stream(conn_t *connp, ldi_ident_t li)
{
        ip_helper_stream_info_t *helper;
        int     error;
        int     ret;

        ASSERT(!servicing_interrupt());

        if (connp->conn_helper_info != NULL) {
                /* Already allocated */
                return (0);
        }

        error = 0;
        helper = kmem_alloc(sizeof (ip_helper_stream_info_t), KM_SLEEP);

        /*
         * open ip device via the layered interface.
         * pass in kcred as some threads do not have the
         * priviledge to open /dev/ip and the check in
         * secpolicy_spec_open() will fail the open
         */
        error = ldi_open_by_name((connp->conn_family == AF_INET6 ? DEV_IP6 :
            DEV_IP), IP_HELPER_STR, kcred, &helper->iphs_handle, li);

        if (error != 0) {
                kmem_free(helper, sizeof (ip_helper_stream_info_t));
                return (error);
        }
        /* Make sure we are the only one */
        mutex_enter(&connp->conn_lock);
        if (connp->conn_helper_info != NULL) {
                /* Some other thread won - discard this stream */
                mutex_exit(&connp->conn_lock);
                (void) ldi_close(helper->iphs_handle, 0, kcred);
                kmem_free(helper, sizeof (ip_helper_stream_info_t));
                return (0);
        }
        connp->conn_helper_info = helper;
        /*
         * Share connp with the helper stream. We hold conn_lock across this
         * operation.
         */
        error = ldi_ioctl(helper->iphs_handle, SIOCSQPTR, (intptr_t)connp,
            FKIOCTL, kcred, &ret);

        if (error != 0) {
                /*
                 * Passing in a zero flag indicates that an error
                 * occured and stream was not shared
                 */
                (void) ldi_close(helper->iphs_handle, 0, kcred);
                kmem_free(helper, sizeof (ip_helper_stream_info_t));
                connp->conn_helper_info = NULL;
        }
        mutex_exit(&connp->conn_lock);
        return (error);
}

/*
 * Public interface for freeing IP helper stream
 * Caller must ensure no concurrent use of the conn_t, which is normally
 * done by calling this from the close routine when the conn_t is quiesced.
 */
void
ip_free_helper_stream(conn_t *connp)
{
        ASSERT(!servicing_interrupt());

        if (connp->conn_helper_info == NULL)
                return;

        ASSERT(connp->conn_helper_info->iphs_handle != NULL);

        connp->conn_helper_info->iphs_rq->q_ptr =
            connp->conn_helper_info->iphs_wq->q_ptr =
            connp->conn_helper_info->iphs_minfo;
        (void) ldi_close(connp->conn_helper_info->iphs_handle,
            IP_HELPER_STR, kcred);
        kmem_free(connp->conn_helper_info, sizeof (ip_helper_stream_info_t));
        connp->conn_helper_info = NULL;
}