fs/dev/sdev_netops.c

/*
 * 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) == NULL) {
        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
};