/*
 * 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.
 */

/*
 * vnode ops for the /dev/net directory
 *
 *      The lookup is based on the internal vanity naming node table.  We also
 *      override readdir in order to delete net nodes no longer in-use.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysmacros.h>
#include <sys/sunndi.h>
#include <fs/fs_subr.h>
#include <sys/fs/dv_node.h>
#include <sys/fs/sdev_impl.h>
#include <sys/policy.h>
#include <sys/zone.h>
#include <sys/dls.h>

struct vnodeops         *devnet_vnodeops;

/*
 * Check if a net sdev_node is still valid - i.e. it represents a current
 * network link.
 * This serves two purposes
 *      - only valid net nodes are returned during lookup() and readdir().
 *      - since net sdev_nodes are not actively destroyed when a network link
 *        goes away, we use the validator to do deferred cleanup i.e. when such
 *        nodes are encountered during subsequent lookup() and readdir().
 */
int
devnet_validate(struct sdev_node *dv)
{
        datalink_id_t linkid;
        zoneid_t zoneid;

        ASSERT(dv->sdev_state == SDEV_READY);

        if (dls_mgmt_get_linkid(dv->sdev_name, &linkid) != 0)
                return (SDEV_VTOR_INVALID);
        if (SDEV_IS_GLOBAL(dv))
                return (SDEV_VTOR_VALID);
        zoneid = getzoneid();
        return (zone_check_datalink(&zoneid, linkid) == 0 ?
            SDEV_VTOR_VALID : SDEV_VTOR_INVALID);
}

/*
 * This callback is invoked from devname_lookup_func() to create
 * a net entry when the node is not found in the cache.
 */
static int
devnet_create_rvp(const char *nm, struct vattr *vap, dls_dl_handle_t *ddhp)
{
        timestruc_t now;
        dev_t dev;
        int error;

        if ((error = dls_devnet_open(nm, ddhp, &dev)) != 0) {
                sdcmn_err12(("devnet_create_rvp: not a valid vanity name "
                    "network node: %s\n", nm));
                return (error);
        }

        /*
         * This is a valid network device (at least at this point in time).
         * Create the node by setting the attribute; the rest is taken care
         * of by devname_lookup_func().
         */
        *vap = sdev_vattr_chr;
        vap->va_mode |= 0666;
        vap->va_rdev = dev;

        gethrestime(&now);
        vap->va_atime = now;
        vap->va_mtime = now;
        vap->va_ctime = now;
        return (0);
}

/*
 * Lookup for /dev/net directory
 *      If the entry does not exist, the devnet_create_rvp() callback
 *      is invoked to create it.  Nodes do not persist across reboot.
 */
/*ARGSUSED3*/
static int
devnet_lookup(struct vnode *dvp, char *nm, struct vnode **vpp,
    struct pathname *pnp, int flags, struct vnode *rdir, struct cred *cred,
    caller_context_t *ct, int *direntflags, pathname_t *realpnp)
{
        struct sdev_node *ddv = VTOSDEV(dvp);
        struct sdev_node *dv = NULL;
        dls_dl_handle_t ddh = NULL;
        struct vattr vattr;
        int nmlen;
        int error = ENOENT;

        if (SDEVTOV(ddv)->v_type != VDIR)
                return (ENOTDIR);

        /*
         * Empty name or ., return node itself.
         */
        nmlen = strlen(nm);
        if ((nmlen == 0) || ((nmlen == 1) && (nm[0] == '.'))) {
                *vpp = SDEVTOV(ddv);
                VN_HOLD(*vpp);
                return (0);
        }

        /*
         * .., return the parent directory
         */
        if ((nmlen == 2) && (strcmp(nm, "..") == 0)) {
                *vpp = SDEVTOV(ddv->sdev_dotdot);
                VN_HOLD(*vpp);
                return (0);
        }

        rw_enter(&ddv->sdev_contents, RW_WRITER);

        /*
         * directory cache lookup:
         */
        if ((dv = sdev_cache_lookup(ddv, nm)) != NULL) {
                ASSERT(dv->sdev_state == SDEV_READY);
                if (!(dv->sdev_flags & SDEV_ATTR_INVALID))
                        goto found;
        }

        /*
         * ZOMBIED parent does not allow new node creation, bail out early.
         */
        if (ddv->sdev_state == SDEV_ZOMBIE)
                goto failed;

        error = devnet_create_rvp(nm, &vattr, &ddh);
        if (error != 0)
                goto failed;

        error = sdev_mknode(ddv, nm, &dv, &vattr, NULL, NULL, cred, SDEV_READY);
        if (error != 0) {
                dls_devnet_close(ddh);
                goto failed;
        }

        ASSERT(dv != NULL);

        rw_enter(&dv->sdev_contents, RW_WRITER);
        if (dv->sdev_flags & SDEV_ATTR_INVALID) {
                /*
                 * SDEV_ATTR_INVALID means that this device has been
                 * detached, and its dev_t might've been changed too.
                 * Therefore, sdev_node's 'vattr' needs to be updated.
                 */
                SDEVTOV(dv)->v_rdev = vattr.va_rdev;
                ASSERT(dv->sdev_attr != NULL);
                dv->sdev_attr->va_rdev = vattr.va_rdev;
                dv->sdev_flags &= ~SDEV_ATTR_INVALID;
        }
        ASSERT(dv->sdev_private == NULL);
        dv->sdev_private = ddh;
        rw_exit(&dv->sdev_contents);

found:
        ASSERT(SDEV_HELD(dv));
        rw_exit(&ddv->sdev_contents);
        return (sdev_to_vp(dv, vpp));

failed:
        rw_exit(&ddv->sdev_contents);

        if (dv != NULL)
                SDEV_RELE(dv);

        *vpp = NULL;
        return (error);
}

static int
devnet_filldir_datalink(datalink_id_t linkid, void *arg)
{
        struct sdev_node        *ddv = arg;
        struct vattr            vattr;
        struct sdev_node        *dv;
        dls_dl_handle_t         ddh = NULL;
        char                    link[MAXLINKNAMELEN];

        ASSERT(RW_WRITE_HELD(&ddv->sdev_contents));

        if (dls_mgmt_get_linkinfo(linkid, link, NULL, NULL, NULL) != 0)
                return (0);

        if ((dv = sdev_cache_lookup(ddv, (char *)link)) != NULL)
                goto found;

        if (devnet_create_rvp(link, &vattr, &ddh) != 0)
                return (0);

        ASSERT(ddh != NULL);
        dls_devnet_close(ddh);

        if (sdev_mknode(ddv, (char *)link, &dv, &vattr, NULL, NULL, kcred,
            SDEV_READY) != 0) {
                return (0);
        }

        /*
         * As there is no reference holding the network device, it could be
         * detached. Set SDEV_ATTR_INVALID so that the 'vattr' will be updated
         * later.
         */
        rw_enter(&dv->sdev_contents, RW_WRITER);
        dv->sdev_flags |= SDEV_ATTR_INVALID;
        rw_exit(&dv->sdev_contents);

found:
        SDEV_SIMPLE_RELE(dv);
        return (0);
}

static void
devnet_filldir(struct sdev_node *ddv)
{
        sdev_node_t     *dv, *next;
        datalink_id_t   linkid;

        ASSERT(RW_READ_HELD(&ddv->sdev_contents));
        if (rw_tryupgrade(&ddv->sdev_contents) == 0) {
                rw_exit(&ddv->sdev_contents);
                rw_enter(&ddv->sdev_contents, RW_WRITER);
        }

        for (dv = SDEV_FIRST_ENTRY(ddv); dv; dv = next) {
                next = SDEV_NEXT_ENTRY(ddv, dv);

                /* validate and prune only ready nodes */
                if (dv->sdev_state != SDEV_READY)
                        continue;

                switch (devnet_validate(dv)) {
                case SDEV_VTOR_VALID:
                case SDEV_VTOR_SKIP:
                        continue;
                case SDEV_VTOR_INVALID:
                case SDEV_VTOR_STALE:
                        sdcmn_err12(("devnet_filldir: destroy invalid "
                            "node: %s(%p)\n", dv->sdev_name, (void *)dv));
                        break;
                }

                if (SDEVTOV(dv)->v_count > 0)
                        continue;
                SDEV_HOLD(dv);
                /* remove the cache node */
                (void) sdev_cache_update(ddv, &dv, dv->sdev_name,
                    SDEV_CACHE_DELETE);
                SDEV_RELE(dv);
        }

        if (((ddv->sdev_flags & SDEV_BUILD) == 0) && !dls_devnet_rebuild())
                goto done;

        if (SDEV_IS_GLOBAL(ddv)) {
                linkid = DATALINK_INVALID_LINKID;
                do {
                        linkid = dls_mgmt_get_next(linkid, DATALINK_CLASS_ALL,
                            DATALINK_ANY_MEDIATYPE, DLMGMT_ACTIVE);
                        if (linkid != DATALINK_INVALID_LINKID)
                                (void) devnet_filldir_datalink(linkid, ddv);
                } while (linkid != DATALINK_INVALID_LINKID);
        } else {
                (void) zone_datalink_walk(getzoneid(),
                    devnet_filldir_datalink, ddv);
        }

        ddv->sdev_flags &= ~SDEV_BUILD;

done:
        rw_downgrade(&ddv->sdev_contents);
}

/*
 * Display all instantiated network datalink device nodes.
 * A /dev/net entry will be created only after the first lookup of
 * the network datalink device succeeds.
 */
/*ARGSUSED4*/
static int
devnet_readdir(struct vnode *dvp, struct uio *uiop, struct cred *cred,
    int *eofp, caller_context_t *ct, int flags)
{
        struct sdev_node *sdvp = VTOSDEV(dvp);

        ASSERT(sdvp);

        if (uiop->uio_offset == 0)
                devnet_filldir(sdvp);

        return (devname_readdir_func(dvp, uiop, cred, eofp, 0));
}

/*
 * This callback is invoked from devname_inactive_func() to release
 * the net entry which was held in devnet_create_rvp().
 */
static void
devnet_inactive_callback(struct vnode *dvp)
{
        struct sdev_node *sdvp = VTOSDEV(dvp);
        dls_dl_handle_t ddh;

        if (dvp->v_type == VDIR)
                return;

        ASSERT(dvp->v_type == VCHR);
        rw_enter(&sdvp->sdev_contents, RW_WRITER);
        ddh = sdvp->sdev_private;
        sdvp->sdev_private = NULL;
        sdvp->sdev_flags |= SDEV_ATTR_INVALID;
        rw_exit(&sdvp->sdev_contents);

        /*
         * "ddh" (sdev_private) could be NULL if devnet_lookup fails.
         */
        if (ddh != NULL)
                dls_devnet_close(ddh);
}

/*ARGSUSED*/
static void
devnet_inactive(struct vnode *dvp, struct cred *cred, caller_context_t *ct)
{
        devname_inactive_func(dvp, cred, devnet_inactive_callback);
}

/*
 * We override lookup and readdir to build entries based on the
 * in kernel vanity naming node table.
 */
const fs_operation_def_t devnet_vnodeops_tbl[] = {
        VOPNAME_READDIR,        { .vop_readdir = devnet_readdir },
        VOPNAME_LOOKUP,         { .vop_lookup = devnet_lookup },
        VOPNAME_INACTIVE,       { .vop_inactive = devnet_inactive },
        VOPNAME_CREATE,         { .error = fs_nosys },
        VOPNAME_REMOVE,         { .error = fs_nosys },
        VOPNAME_MKDIR,          { .error = fs_nosys },
        VOPNAME_RMDIR,          { .error = fs_nosys },
        VOPNAME_SYMLINK,        { .error = fs_nosys },
        VOPNAME_SETSECATTR,     { .error = fs_nosys },
        NULL,                   NULL
};