smbclnt/netsmb/smb_smb.c

	smb_smb.c revision ae3d7f90695ef456a6da4f7bdccd448ebe0b99e1
/*
 * Copyright (c) 2000-2001 Boris Popov
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by Boris Popov.
 * 4. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $Id: smb_smb.c,v 1.35.100.2 2005/06/02 00:55:39 lindak Exp $
 */

/*
 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*
 * various SMB requests. Most of the routines merely packs data into mbufs.
 */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kmem.h>
#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/random.h>
#include <sys/note.h>
#include <sys/cmn_err.h>

#include <netsmb/smb_osdep.h>

#include <netsmb/smb.h>
#include <netsmb/smb_conn.h>
#include <netsmb/smb_rq.h>
#include <netsmb/smb_subr.h>
#include <netsmb/smb_tran.h>

/*
 * Largest size to use with LARGE_READ/LARGE_WRITE.
 * Specs say up to 64k data bytes, but Windows traffic
 * uses 60k... no doubt for some good reason.
 * (Probably to keep 4k block alignment.)
 * XXX: Move to smb.h maybe?
 */
#define SMB_MAX_LARGE_RW_SIZE (60*1024)

/*
 * Default timeout values, all in seconds.
 * Make these tunable (only via mdb for now).
 */
int smb_timo_notice = 15;
int smb_timo_default = 30;  /* was SMB_DEFRQTIMO */
int smb_timo_open = 45;
int smb_timo_read = 45;
int smb_timo_write = 60;    /* was SMBWRTTIMO */
int smb_timo_append = 90;

static int smb_smb_read(struct smb_share *ssp, uint16_t fid,
    uint32_t *lenp, uio_t *uiop, smb_cred_t *scred, int timo);
static int smb_smb_write(struct smb_share *ssp, uint16_t fid,
    uint32_t *lenp, uio_t *uiop, smb_cred_t *scred, int timo);

static int smb_smb_readx(struct smb_share *ssp, uint16_t fid,
    uint32_t *lenp, uio_t *uiop, smb_cred_t *scred, int timo);
static int smb_smb_writex(struct smb_share *ssp, uint16_t fid,
    uint32_t *lenp, uio_t *uiop, smb_cred_t *scred, int timo);

int
smb_smb_treeconnect(struct smb_share *ssp, struct smb_cred *scred)
{
    struct smb_vc *vcp;
    struct smb_rq *rqp = NULL;
    struct mbchain *mbp;
    struct mdchain *mdp;
    char *pbuf, *unc_name = NULL;
    int error, tlen, plen, unc_len;
    uint16_t bcnt, options;
    uint8_t wc;

    vcp = SSTOVC(ssp);

    /*
     * Make this a "VC-level" request, so it will have
     * rqp->sr_share == NULL, and smb_iod_sendrq()
     * will send it with TID = SMB_TID_UNKNOWN
     *
     * This also serves to bypass the wait for
     * share state changes, which this call is
     * trying to carry out.
     */
    error = smb_rq_alloc(VCTOCP(vcp), SMB_COM_TREE_CONNECT_ANDX,
        scred, &rqp);
    if (error)
        return (error);

    /*
     * Build the UNC name, i.e. "//server/share"
     * but with backslashes of course.
     * size math: three slashes, one null.
     */
    unc_len = 4 + strlen(vcp->vc_srvname) + strlen(ssp->ss_name);
    unc_name = kmem_alloc(unc_len, KM_SLEEP);
    (void) snprintf(unc_name, unc_len, "\\\\%s\\%s",
        vcp->vc_srvname, ssp->ss_name);
    SMBSDEBUG("unc_name: \"%s\"", unc_name);

    /*
     * The password is now pre-computed in the
     * user-space helper process.
     */
    plen = ssp->ss_pwlen;
    pbuf = ssp->ss_pass;

    /*
     * Build the request.
     */
    mbp = &rqp->sr_rq;
    smb_rq_wstart(rqp);
    mb_put_uint8(mbp, 0xff);
    mb_put_uint8(mbp, 0);
    mb_put_uint16le(mbp, 0);
    mb_put_uint16le(mbp, 0);        /* Flags */
    mb_put_uint16le(mbp, plen);
    smb_rq_wend(rqp);
    smb_rq_bstart(rqp);

    /* Tree connect password, if any */
    error = mb_put_mem(mbp, pbuf, plen, MB_MSYSTEM);
    if (error)
        goto out;

    /* UNC resource name */
    error = smb_put_dstring(mbp, vcp, unc_name, SMB_CS_NONE);
    if (error)
        goto out;

    /*
     * Put the type string (always ASCII),
     * including the null.
     */
    tlen = strlen(ssp->ss_type_req) + 1;
    error = mb_put_mem(mbp, ssp->ss_type_req, tlen, MB_MSYSTEM);
    if (error)
        goto out;

    smb_rq_bend(rqp);

    /*
     * Run the request.
     *
     * Using NOINTR_RECV because we don't want to risk
     * missing a successful tree connect response,
     * which would "leak" Tree IDs.
     */
    rqp->sr_flags |= SMBR_NOINTR_RECV;
    error = smb_rq_simple(rqp);
    SMBSDEBUG("%d\n", error);
    if (error) {
        /*
         * If we get the server name wrong, i.e. due to
         * mis-configured name services, this will be
         * NT_STATUS_DUPLICATE_NAME.  Log this error.
         */
        SMBERROR("(%s) failed, status=0x%x",
            unc_name, rqp->sr_error);
        goto out;
    }

    /*
     * Parse the TCON response
     */
    smb_rq_getreply(rqp, &mdp);
    md_get_uint8(mdp, &wc);
    if (wc != 3 && wc != 7) {
        error = EBADRPC;
        goto out;
    }
    md_get_uint16le(mdp, NULL);     /* AndX cmd */
    md_get_uint16le(mdp, NULL);     /* AndX off */
    md_get_uint16le(mdp, &options);     /* option bits (DFS, search) */
    if (wc == 7) {
        md_get_uint32le(mdp, NULL); /* MaximalShareAccessRights */
        md_get_uint32le(mdp, NULL); /* GuestMaximalShareAcc... */
    }
    error = md_get_uint16le(mdp, &bcnt);    /* byte count */
    if (error)
        goto out;

    /*
     * Get the returned share type string,
     * i.e. "IPC" or whatever.   Don't care
     * if we get an error reading the type.
     */
    tlen = sizeof (ssp->ss_type_ret);
    bzero(ssp->ss_type_ret, tlen--);
    if (tlen > bcnt)
        tlen = bcnt;
    md_get_mem(mdp, ssp->ss_type_ret, tlen, MB_MSYSTEM);

    /* Success! */
    SMB_SS_LOCK(ssp);
    ssp->ss_tid = rqp->sr_rptid;
    ssp->ss_vcgenid = vcp->vc_genid;
    ssp->ss_options = options;
    ssp->ss_flags |= SMBS_CONNECTED;
    SMB_SS_UNLOCK(ssp);

out:
    if (unc_name)
        kmem_free(unc_name, unc_len);
    smb_rq_done(rqp);
    return (error);
}

int
smb_smb_treedisconnect(struct smb_share *ssp, struct smb_cred *scred)
{
    struct smb_vc *vcp;
    struct smb_rq *rqp;
    int error;

    if (ssp->ss_tid == SMB_TID_UNKNOWN)
        return (0);

    /*
     * Build this as a "VC-level" request, so it will
     * avoid testing the _GONE flag on the share,
     * which has already been set at this point.
     * Add the share pointer "by hand" below, so
     * smb_iod_sendrq will plug in the TID.
     */
    vcp = SSTOVC(ssp);
    error = smb_rq_alloc(VCTOCP(vcp), SMB_COM_TREE_DISCONNECT, scred, &rqp);
    if (error)
        return (error);
    rqp->sr_share = ssp; /* by hand */

    smb_rq_wstart(rqp);
    smb_rq_wend(rqp);
    smb_rq_bstart(rqp);
    smb_rq_bend(rqp);

    /*
     * Run this with a relatively short timeout. (5 sec.)
     * We don't really care about the result here, but we
     * do need to make sure we send this out, or we could
     * "leak" active tree IDs on interrupt or timeout.
     * The NOINTR_SEND flag makes this request immune to
     * interrupt or timeout until the send is done.
     * Also, don't reconnect for this, of course!
     */
    rqp->sr_flags |= (SMBR_NOINTR_SEND | SMBR_NORECONNECT);
    error = smb_rq_simple_timed(rqp, 5);
    SMBSDEBUG("%d\n", error);
    smb_rq_done(rqp);
    ssp->ss_tid = SMB_TID_UNKNOWN;
    return (error);
}

/*
 * Common function for read/write with UIO.
 * Called by netsmb smb_usr_rw,
 *  smbfs_readvnode, smbfs_writevnode
 */
int
smb_rwuio(struct smb_share *ssp, uint16_t fid, uio_rw_t rw,
    uio_t *uiop, smb_cred_t *scred, int timo)
{
    struct smb_vc *vcp = SSTOVC(ssp);
    ssize_t  save_resid;
    uint32_t len, rlen, maxlen;
    int error = 0;
    int (*iofun)(struct smb_share *, uint16_t, uint32_t *,
        uio_t *, smb_cred_t *, int);

    /*
     * Determine which function to use,
     * and the transfer size per call.
     */
    if (SMB_DIALECT(vcp) >= SMB_DIALECT_NTLM0_12) {
        /*
         * Using NT LM 0.12, so readx, writex.
         * Make sure we can represent the offset.
         */
        if ((vcp->vc_sopt.sv_caps & SMB_CAP_LARGE_FILES) == 0 &&
            (uiop->uio_loffset + uiop->uio_resid) > UINT32_MAX)
            return (EFBIG);

        if (rw == UIO_READ) {
            iofun = smb_smb_readx;
            if (vcp->vc_sopt.sv_caps & SMB_CAP_LARGE_READX)
                maxlen = SMB_MAX_LARGE_RW_SIZE;
            else
                maxlen = vcp->vc_rxmax;
        } else { /* UIO_WRITE */
            iofun = smb_smb_writex;
            if (vcp->vc_sopt.sv_caps & SMB_CAP_LARGE_WRITEX)
                maxlen = SMB_MAX_LARGE_RW_SIZE;
            else
                maxlen = vcp->vc_wxmax;
        }
    } else {
        /*
         * Using the old SMB_READ and SMB_WRITE so
         * we're limited to 32-bit offsets, etc.
         * XXX: Someday, punt the old dialects.
         */
        if ((uiop->uio_loffset + uiop->uio_resid) > UINT32_MAX)
            return (EFBIG);

        if (rw == UIO_READ) {
            iofun = smb_smb_read;
            maxlen = vcp->vc_rxmax;
        } else { /* UIO_WRITE */
            iofun = smb_smb_write;
            maxlen = vcp->vc_wxmax;
        }
    }

    save_resid = uiop->uio_resid;
    while (uiop->uio_resid > 0) {
        /* Lint: uio_resid may be 64-bits */
        rlen = len = (uint32_t)min(maxlen, uiop->uio_resid);
        error = (*iofun)(ssp, fid, &rlen, uiop, scred, timo);

        /*
         * Note: the iofun called uio_update, so
         * not doing that here as one might expect.
         *
         * Quit the loop either on error, or if we
         * transferred less then requested.
         */
        if (error || (rlen < len))
            break;

        timo = 0; /* only first I/O should wait */
    }
    if (error && (save_resid != uiop->uio_resid)) {
        /*
         * Stopped on an error after having
         * successfully transferred data.
         * Suppress this error.
         */
        SMBSDEBUG("error %d suppressed\n", error);
        error = 0;
    }

    return (error);
}

static int
smb_smb_readx(struct smb_share *ssp, uint16_t fid, uint32_t *lenp,
    uio_t *uiop, smb_cred_t *scred, int timo)
{
    struct smb_rq *rqp;
    struct mbchain *mbp;
    struct mdchain *mdp;
    int error;
    uint32_t offlo, offhi, rlen;
    uint16_t lenhi, lenlo, off, doff;
    uint8_t wc;

    lenhi = (uint16_t)(*lenp >> 16);
    lenlo = (uint16_t)*lenp;
    offhi = (uint32_t)(uiop->uio_loffset >> 32);
    offlo = (uint32_t)uiop->uio_loffset;

    error = smb_rq_alloc(SSTOCP(ssp), SMB_COM_READ_ANDX, scred, &rqp);
    if (error)
        return (error);
    smb_rq_getrequest(rqp, &mbp);
    smb_rq_wstart(rqp);
    mb_put_uint8(mbp, 0xff);    /* no secondary command */
    mb_put_uint8(mbp, 0);       /* MBZ */
    mb_put_uint16le(mbp, 0);    /* offset to secondary */
    mb_put_uint16le(mbp, fid);
    mb_put_uint32le(mbp, offlo);    /* offset (low part) */
    mb_put_uint16le(mbp, lenlo);    /* MaxCount */
    mb_put_uint16le(mbp, 1);    /* MinCount */
                    /* (only indicates blocking) */
    mb_put_uint32le(mbp, lenhi);    /* MaxCountHigh */
    mb_put_uint16le(mbp, lenlo);    /* Remaining ("obsolete") */
    mb_put_uint32le(mbp, offhi);    /* offset (high part) */
    smb_rq_wend(rqp);
    smb_rq_bstart(rqp);
    smb_rq_bend(rqp);

    if (timo == 0)
        timo = smb_timo_read;
    error = smb_rq_simple_timed(rqp, timo);
    if (error)
        goto out;

    smb_rq_getreply(rqp, &mdp);
    error = md_get_uint8(mdp, &wc);
    if (error)
        goto out;
    if (wc != 12) {
        error = EBADRPC;
        goto out;
    }
    md_get_uint8(mdp, NULL);
    md_get_uint8(mdp, NULL);
    md_get_uint16le(mdp, NULL);
    md_get_uint16le(mdp, NULL);
    md_get_uint16le(mdp, NULL); /* data compaction mode */
    md_get_uint16le(mdp, NULL);
    md_get_uint16le(mdp, &lenlo);   /* data len ret. */
    md_get_uint16le(mdp, &doff);    /* data offset */
    md_get_uint16le(mdp, &lenhi);
    rlen = (lenhi << 16) | lenlo;
    md_get_mem(mdp, NULL, 4 * 2, MB_MSYSTEM);
    error = md_get_uint16le(mdp, NULL); /* ByteCount */
    if (error)
        goto out;
    /*
     * Does the data offset indicate padding?
     * The current offset is a constant, found
     * by counting the md_get_ calls above.
     */
    off = SMB_HDRLEN + 3 + (12 * 2); /* =59 */
    if (doff > off) /* pad byte(s)? */
        md_get_mem(mdp, NULL, doff - off, MB_MSYSTEM);
    if (rlen == 0) {
        *lenp = rlen;
        goto out;
    }
    /* paranoid */
    if (rlen > *lenp) {
        SMBSDEBUG("bad server! rlen %d, len %d\n",
            rlen, *lenp);
        rlen = *lenp;
    }
    error = md_get_uio(mdp, uiop, rlen);
    if (error)
        goto out;

    /* Success */
    *lenp = rlen;

out:
    smb_rq_done(rqp);
    return (error);
}

static int
smb_smb_writex(struct smb_share *ssp, uint16_t fid, uint32_t *lenp,
    uio_t *uiop, smb_cred_t *scred, int timo)
{
    struct smb_rq *rqp;
    struct mbchain *mbp;
    struct mdchain *mdp;
    int error;
    uint32_t offlo, offhi, rlen;
    uint16_t lenhi, lenlo;
    uint8_t wc;

    lenhi = (uint16_t)(*lenp >> 16);
    lenlo = (uint16_t)*lenp;
    offhi = (uint32_t)(uiop->uio_loffset >> 32);
    offlo = (uint32_t)uiop->uio_loffset;

    error = smb_rq_alloc(SSTOCP(ssp), SMB_COM_WRITE_ANDX, scred, &rqp);
    if (error)
        return (error);
    smb_rq_getrequest(rqp, &mbp);
    smb_rq_wstart(rqp);
    mb_put_uint8(mbp, 0xff);    /* no secondary command */
    mb_put_uint8(mbp, 0);       /* MBZ */
    mb_put_uint16le(mbp, 0);    /* offset to secondary */
    mb_put_uint16le(mbp, fid);
    mb_put_uint32le(mbp, offlo);    /* offset (low part) */
    mb_put_uint32le(mbp, 0);    /* MBZ (timeout) */
    mb_put_uint16le(mbp, 0);    /* !write-thru */
    mb_put_uint16le(mbp, 0);
    mb_put_uint16le(mbp, lenhi);
    mb_put_uint16le(mbp, lenlo);
    mb_put_uint16le(mbp, 64);   /* data offset from header start */
    mb_put_uint32le(mbp, offhi);    /* offset (high part) */
    smb_rq_wend(rqp);
    smb_rq_bstart(rqp);

    mb_put_uint8(mbp, 0);   /* pad byte */
    error = mb_put_uio(mbp, uiop, *lenp);
    if (error)
        goto out;
    smb_rq_bend(rqp);
    if (timo == 0)
        timo = smb_timo_write;
    error = smb_rq_simple_timed(rqp, timo);
    if (error)
        goto out;
    smb_rq_getreply(rqp, &mdp);
    error = md_get_uint8(mdp, &wc);
    if (error)
        goto out;
    if (wc != 6) {
        error = EBADRPC;
        goto out;
    }
    md_get_uint8(mdp, NULL);    /* andx cmd */
    md_get_uint8(mdp, NULL);    /* reserved */
    md_get_uint16le(mdp, NULL); /* andx offset */
    md_get_uint16le(mdp, &lenlo);   /* data len ret. */
    md_get_uint16le(mdp, NULL); /* remaining */
    error = md_get_uint16le(mdp, &lenhi);
    if (error)
        goto out;

    /* Success */
    rlen = (lenhi << 16) | lenlo;
    *lenp = rlen;

out:
    smb_rq_done(rqp);
    return (error);
}

static int
smb_smb_read(struct smb_share *ssp, uint16_t fid, uint32_t *lenp,
    uio_t *uiop, smb_cred_t *scred, int timo)
{
    struct smb_rq *rqp;
    struct mbchain *mbp;
    struct mdchain *mdp;
    int error;
    uint32_t off32;
    uint16_t bc, cnt, dlen, rcnt, todo;
    uint8_t wc;

    ASSERT(uiop->uio_loffset <= UINT32_MAX);
    off32 = (uint32_t)uiop->uio_loffset;
    ASSERT(*lenp <= UINT16_MAX);
    cnt = (uint16_t)*lenp;
    /* This next is an "estimate" of planned reads. */
    todo = (uint16_t)min(uiop->uio_resid, UINT16_MAX);

    error = smb_rq_alloc(SSTOCP(ssp), SMB_COM_READ, scred, &rqp);
    if (error)
        return (error);
    smb_rq_getrequest(rqp, &mbp);
    smb_rq_wstart(rqp);
    mb_put_uint16le(mbp, fid);
    mb_put_uint16le(mbp, cnt);
    mb_put_uint32le(mbp, off32);
    mb_put_uint16le(mbp, todo);
    smb_rq_wend(rqp);
    smb_rq_bstart(rqp);
    smb_rq_bend(rqp);

    if (timo == 0)
        timo = smb_timo_read;
    error = smb_rq_simple_timed(rqp, timo);
    if (error)
        goto out;
    smb_rq_getreply(rqp, &mdp);
    error = md_get_uint8(mdp, &wc);
    if (error)
        goto out;
    if (wc != 5) {
        error = EBADRPC;
        goto out;
    }
    md_get_uint16le(mdp, &rcnt);        /* ret. count */
    md_get_mem(mdp, NULL, 4 * 2, MB_MSYSTEM);  /* res. */
    md_get_uint16le(mdp, &bc);      /* byte count */
    md_get_uint8(mdp, NULL);        /* buffer format */
    error = md_get_uint16le(mdp, &dlen);    /* data len */
    if (error)
        goto out;
    if (dlen < rcnt) {
        SMBSDEBUG("oops: dlen=%d rcnt=%d\n",
            (int)dlen, (int)rcnt);
        rcnt = dlen;
    }
    if (rcnt == 0) {
        *lenp = 0;
        goto out;
    }
    /* paranoid */
    if (rcnt > cnt) {
        SMBSDEBUG("bad server! rcnt %d, cnt %d\n",
            (int)rcnt, (int)cnt);
        rcnt = cnt;
    }
    error = md_get_uio(mdp, uiop, (int)rcnt);
    if (error)
        goto out;

    /* success */
    *lenp = (int)rcnt;

out:
    smb_rq_done(rqp);
    return (error);
}

static int
smb_smb_write(struct smb_share *ssp, uint16_t fid, uint32_t *lenp,
    uio_t *uiop, smb_cred_t *scred, int timo)
{
    struct smb_rq *rqp;
    struct mbchain *mbp;
    struct mdchain *mdp;
    int error;
    uint32_t off32;
    uint16_t cnt, rcnt, todo;
    uint8_t wc;

    ASSERT(uiop->uio_loffset <= UINT32_MAX);
    off32 = (uint32_t)uiop->uio_loffset;
    ASSERT(*lenp <= UINT16_MAX);
    cnt = (uint16_t)*lenp;
    /* This next is an "estimate" of planned writes. */
    todo = (uint16_t)min(uiop->uio_resid, UINT16_MAX);

    error = smb_rq_alloc(SSTOCP(ssp), SMB_COM_WRITE, scred, &rqp);
    if (error)
        return (error);
    smb_rq_getrequest(rqp, &mbp);
    smb_rq_wstart(rqp);
    mb_put_uint16le(mbp, fid);
    mb_put_uint16le(mbp, cnt);
    mb_put_uint32le(mbp, off32);
    mb_put_uint16le(mbp, todo);
    smb_rq_wend(rqp);
    smb_rq_bstart(rqp);
    mb_put_uint8(mbp, SMB_DT_DATA);
    mb_put_uint16le(mbp, cnt);

    error = mb_put_uio(mbp, uiop, *lenp);
    if (error)
        goto out;
    smb_rq_bend(rqp);
    if (timo == 0)
        timo = smb_timo_write;
    error = smb_rq_simple_timed(rqp, timo);
    if (error)
        goto out;
    smb_rq_getreply(rqp, &mdp);
    error = md_get_uint8(mdp, &wc);
    if (error)
        goto out;
    if (wc != 1) {
        error = EBADRPC;
        goto out;
    }
    error = md_get_uint16le(mdp, &rcnt);
    if (error)
        goto out;
    *lenp = rcnt;

out:
    smb_rq_done(rqp);
    return (error);
}


static u_int32_t    smbechoes = 0;

int
smb_smb_echo(struct smb_vc *vcp, struct smb_cred *scred, int timo)
{
    struct smb_rq *rqp;
    struct mbchain *mbp;
    int error;

    error = smb_rq_alloc(VCTOCP(vcp), SMB_COM_ECHO, scred, &rqp);
    if (error)
        return (error);
    mbp = &rqp->sr_rq;
    smb_rq_wstart(rqp);
    mb_put_uint16le(mbp, 1); /* echo count */
    smb_rq_wend(rqp);
    smb_rq_bstart(rqp);
    mb_put_uint32le(mbp, atomic_inc_32_nv(&smbechoes));
    smb_rq_bend(rqp);
    /*
     * Note: the IOD calls this, so
     * this request must not wait for
     * connection state changes, etc.
     */
    rqp->sr_flags |= SMBR_NORECONNECT;
    error = smb_rq_simple_timed(rqp, timo);
    SMBSDEBUG("%d\n", error);
    smb_rq_done(rqp);
    return (error);
}