/*
 * 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.
 *
 * $FreeBSD: src/sys/netsmb/smb_smb.c,v 1.1.2.3 2002/12/14 14:44:19 fjoe Exp $
 */
/*
 * various SMB requests. Most of the routines merely packs data into mbufs.
 */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/sysctl.h>
#include <sys/socket.h>
#include <sys/uio.h>

#include <sys/iconv.h>
#include <machine/limits.h>

#include "smb.h"
#include "smb_subr.h"
#include "smb_rq.h"
#include "smb_conn.h"
#include "smb_tran.h"

#include "opt_netsmb.h"

struct smb_dialect {
        int             d_id;
        const char *    d_name;
};

static struct smb_dialect smb_dialects[] = {
        {SMB_DIALECT_CORE,      "PC NETWORK PROGRAM 1.0"},
        {SMB_DIALECT_COREPLUS,  "MICROSOFT NETWORKS 1.03"},
        {SMB_DIALECT_LANMAN1_0, "MICROSOFT NETWORKS 3.0"},
        {SMB_DIALECT_LANMAN1_0, "LANMAN1.0"},
        {SMB_DIALECT_LANMAN2_0, "LM1.2X002"},
        {SMB_DIALECT_LANMAN2_0, "Samba"},
        {SMB_DIALECT_NTLM0_12,  "NT LANMAN 1.0"},
        {SMB_DIALECT_NTLM0_12,  "NT LM 0.12"},
        {-1,                    NULL}
};

#define SMB_DIALECT_MAX (NELEM(smb_dialects) - 2)

static int
smb_smb_nomux(struct smb_vc *vcp, struct smb_cred *scred, const char *name)
{
        if (scred->scr_td == vcp->vc_iod->iod_td)
                return 0;
        SMBERROR("wrong function called(%s)\n", name);
        return EINVAL;
}

int
smb_smb_negotiate(struct smb_vc *vcp, struct smb_cred *scred)
{
        struct smb_dialect *dp;
        struct smb_sopt *sp = NULL;
        struct smb_rq *rqp;
        struct mbchain *mbp;
        struct mdchain *mdp;
        u_int8_t wc, stime[8], sblen;
        u_int16_t dindex, tw, tw1, swlen, bc;
        int error, maxqsz;

        if (smb_smb_nomux(vcp, scred, __func__) != 0)
                return EINVAL;
        vcp->vc_hflags = 0;
        vcp->vc_hflags2 = 0;
        vcp->obj.co_flags &= ~(SMBV_ENCRYPT);
        sp = &vcp->vc_sopt;
        bzero(sp, sizeof(struct smb_sopt));
        error = smb_rq_alloc(VCTOCP(vcp), SMB_COM_NEGOTIATE, scred, &rqp);
        if (error)
                return error;
        smb_rq_getrequest(rqp, &mbp);
        smb_rq_wstart(rqp);
        smb_rq_wend(rqp);
        smb_rq_bstart(rqp);
        for(dp = smb_dialects; dp->d_id != -1; dp++) {
                mb_put_uint8(mbp, SMB_DT_DIALECT);
                smb_put_dstring(mbp, vcp, dp->d_name, SMB_CS_NONE);
        }
        smb_rq_bend(rqp);
        error = smb_rq_simple(rqp);
        SMBSDEBUG("%d\n", error);
        if (error)
                goto bad;
        smb_rq_getreply(rqp, &mdp);
        do {
                error = md_get_uint8(mdp, &wc);
                if (error)
                        break;
                error = md_get_uint16le(mdp, &dindex);
                if (error)
                        break;
                if (dindex > 7) {
                        SMBERROR("Don't know how to talk with server %s (%d)\n", "xxx", dindex);
                        error = EBADRPC;
                        break;
                }
                dp = smb_dialects + dindex;
                sp->sv_proto = dp->d_id;
                SMBSDEBUG("Dialect %s (%d, %d)\n", dp->d_name, dindex, wc);
                error = EBADRPC;
                if (dp->d_id >= SMB_DIALECT_NTLM0_12) {
                        if (wc != 17)
                                break;
                        md_get_uint8(mdp, &sp->sv_sm);
                        md_get_uint16le(mdp, &sp->sv_maxmux);
                        md_get_uint16le(mdp, &sp->sv_maxvcs);
                        md_get_uint32le(mdp, &sp->sv_maxtx);
                        md_get_uint32le(mdp, &sp->sv_maxraw);
                        md_get_uint32le(mdp, &sp->sv_skey);
                        md_get_uint32le(mdp, &sp->sv_caps);
                        md_get_mem(mdp, stime, 8, MB_MSYSTEM);
                        md_get_uint16le(mdp, (u_int16_t*)&sp->sv_tz);
                        md_get_uint8(mdp, &sblen);
                        if (sblen && (sp->sv_sm & SMB_SM_ENCRYPT)) {
                                if (sblen != SMB_MAXCHALLENGELEN) {
                                        SMBERROR("Unexpected length of security blob (%d)\n", sblen);
                                        break;
                                }
                                error = md_get_uint16(mdp, &bc);
                                if (error)
                                        break;
                                if (sp->sv_caps & SMB_CAP_EXT_SECURITY)
                                        md_get_mem(mdp, NULL, 16, MB_MSYSTEM);
                                error = md_get_mem(mdp, vcp->vc_ch, sblen, MB_MSYSTEM);
                                if (error)
                                        break;
                                vcp->vc_chlen = sblen;
                                vcp->obj.co_flags |= SMBV_ENCRYPT;
                        }
                        if (sp->sv_sm & SMB_SM_SIGS_REQUIRE)
                                vcp->vc_hflags2 |= SMB_FLAGS2_SECURITY_SIGNATURE;
                        vcp->vc_hflags2 |= SMB_FLAGS2_KNOWS_LONG_NAMES;
                        if (dp->d_id == SMB_DIALECT_NTLM0_12 &&
                            sp->sv_maxtx < 4096 &&
                            (sp->sv_caps & SMB_CAP_NT_SMBS) == 0) {
                                vcp->obj.co_flags |= SMBV_WIN95;
                                SMBSDEBUG("Win95 detected\n");
                        }
                } else if (dp->d_id > SMB_DIALECT_CORE) {
                        md_get_uint16le(mdp, &tw);
                        sp->sv_sm = tw;
                        md_get_uint16le(mdp, &tw);
                        sp->sv_maxtx = tw;
                        md_get_uint16le(mdp, &sp->sv_maxmux);
                        md_get_uint16le(mdp, &sp->sv_maxvcs);
                        md_get_uint16le(mdp, &tw);      /* rawmode */
                        md_get_uint32le(mdp, &sp->sv_skey);
                        if (wc == 13) {         /* >= LANMAN1 */
                                md_get_uint16(mdp, &tw);                /* time */
                                md_get_uint16(mdp, &tw1);               /* date */
                                md_get_uint16le(mdp, (u_int16_t*)&sp->sv_tz);
                                md_get_uint16le(mdp, &swlen);
                                if (swlen > SMB_MAXCHALLENGELEN)
                                        break;
                                md_get_uint16(mdp, NULL);       /* mbz */
                                if (md_get_uint16(mdp, &bc) != 0)
                                        break;
                                if (bc < swlen)
                                        break;
                                if (swlen && (sp->sv_sm & SMB_SM_ENCRYPT)) {
                                        error = md_get_mem(mdp, vcp->vc_ch, swlen, MB_MSYSTEM);
                                        if (error)
                                                break;
                                        vcp->vc_chlen = swlen;
                                        vcp->obj.co_flags |= SMBV_ENCRYPT;
                                }
                        }
                        vcp->vc_hflags2 |= SMB_FLAGS2_KNOWS_LONG_NAMES;
                } else {        /* an old CORE protocol */
                        sp->sv_maxmux = 1;
                }
                error = 0;
        } while (0);
        if (error == 0) {
                vcp->vc_maxvcs = sp->sv_maxvcs;
                if (vcp->vc_maxvcs <= 1) {
                        if (vcp->vc_maxvcs == 0)
                                vcp->vc_maxvcs = 1;
                }
                if (sp->sv_maxtx <= 0 || sp->sv_maxtx > 0xffff)
                        sp->sv_maxtx = 1024;
                SMB_TRAN_GETPARAM(vcp, SMBTP_SNDSZ, &maxqsz);
                vcp->vc_txmax = min(sp->sv_maxtx, maxqsz);
                SMBSDEBUG("TZ = %d\n", sp->sv_tz);
                SMBSDEBUG("CAPS = %x\n", sp->sv_caps);
                SMBSDEBUG("MAXMUX = %d\n", sp->sv_maxmux);
                SMBSDEBUG("MAXVCS = %d\n", sp->sv_maxvcs);
                SMBSDEBUG("MAXRAW = %d\n", sp->sv_maxraw);
                SMBSDEBUG("MAXTX = %d\n", sp->sv_maxtx);
        }
bad:
        smb_rq_done(rqp);
        return error;
}

int
smb_smb_ssnsetup(struct smb_vc *vcp, struct smb_cred *scred)
{
        struct smb_rq *rqp;
        struct mbchain *mbp;
/*      u_int8_t wc;
        u_int16_t tw, tw1;*/
        smb_uniptr unipp, ntencpass = NULL;
        char *pp, *up, *pbuf, *encpass;
        int error, plen, uniplen;

        vcp->vc_smbuid = SMB_UID_UNKNOWN;

        if (smb_smb_nomux(vcp, scred, __func__) != 0)
                return EINVAL;

        error = smb_rq_alloc(VCTOCP(vcp), SMB_COM_SESSION_SETUP_ANDX, scred, &rqp);
        if (error)
                return error;
        pbuf = kmalloc(SMB_MAXPASSWORDLEN + 1, M_SMBTEMP, M_WAITOK);
        encpass = kmalloc(24, M_SMBTEMP, M_WAITOK);
        if (vcp->vc_sopt.sv_sm & SMB_SM_USER) {
                iconv_convstr(vcp->vc_toupper, pbuf, smb_vc_getpass(vcp));
                iconv_convstr(vcp->vc_toserver, pbuf, pbuf);
                if (vcp->vc_sopt.sv_sm & SMB_SM_ENCRYPT) {
                        uniplen = plen = 24;
                        smb_encrypt(pbuf, vcp->vc_ch, encpass);
                        ntencpass = kmalloc(uniplen, M_SMBTEMP, M_WAITOK);
                        iconv_convstr(vcp->vc_toserver, pbuf, smb_vc_getpass(vcp));
                        smb_ntencrypt(pbuf, vcp->vc_ch, (u_char*)ntencpass);
                        pp = encpass;
                        unipp = ntencpass;
                } else {
                        plen = strlen(pbuf) + 1;
                        pp = pbuf;
                        uniplen = plen * 2;
                        ntencpass = kmalloc(uniplen, M_SMBTEMP, M_WAITOK);
                        smb_strtouni(ntencpass, smb_vc_getpass(vcp));
                        plen--;

                        /*
                         * The uniplen is zeroed because Samba cannot deal
                         * with this 2nd cleartext password.  This Samba
                         * "bug" is actually a workaround for problems in
                         * Microsoft clients.
                         */
                        uniplen = 0/*-= 2*/;
                        unipp = ntencpass;
                }
        } else {
                /*
                 * In the share security mode password will be used
                 * only in the tree authentication
                 */
                 pp = "";
                 plen = 1;
                 unipp = &smb_unieol;
                 uniplen = 0 /* sizeof(smb_unieol) */;
        }
        smb_rq_wstart(rqp);
        mbp = &rqp->sr_rq;
        up = vcp->vc_username;
        mb_put_uint8(mbp, 0xff);
        mb_put_uint8(mbp, 0);
        mb_put_uint16le(mbp, 0);
        mb_put_uint16le(mbp, vcp->vc_sopt.sv_maxtx);
        mb_put_uint16le(mbp, vcp->vc_sopt.sv_maxmux);
        mb_put_uint16le(mbp, vcp->vc_number);
        mb_put_uint32le(mbp, vcp->vc_sopt.sv_skey);
        mb_put_uint16le(mbp, plen);
        if (SMB_DIALECT(vcp) < SMB_DIALECT_NTLM0_12) {
                mb_put_uint32le(mbp, 0);
                smb_rq_wend(rqp);
                smb_rq_bstart(rqp);
                mb_put_mem(mbp, pp, plen, MB_MSYSTEM);
                smb_put_dstring(mbp, vcp, up, SMB_CS_NONE);
        } else {
                mb_put_uint16le(mbp, uniplen);
                mb_put_uint32le(mbp, 0);                /* reserved */
                mb_put_uint32le(mbp, vcp->obj.co_flags & SMBV_UNICODE ?
                                     SMB_CAP_UNICODE : 0);
                smb_rq_wend(rqp);
                smb_rq_bstart(rqp);
                mb_put_mem(mbp, pp, plen, MB_MSYSTEM);
                mb_put_mem(mbp, (caddr_t)unipp, uniplen, MB_MSYSTEM);
                smb_put_dstring(mbp, vcp, up, SMB_CS_NONE);             /* AccountName */
                smb_put_dstring(mbp, vcp, vcp->vc_domain, SMB_CS_NONE); /* PrimaryDomain */
                smb_put_dstring(mbp, vcp, "FreeBSD", SMB_CS_NONE);      /* Client's OS */
                smb_put_dstring(mbp, vcp, "NETSMB", SMB_CS_NONE);               /* Client name */
        }
        smb_rq_bend(rqp);
        if (ntencpass)
                kfree(ntencpass, M_SMBTEMP);
        if (vcp->vc_hflags2 & SMB_FLAGS2_SECURITY_SIGNATURE)
                smb_calcmackey(vcp);
        error = smb_rq_simple(rqp);
        SMBSDEBUG("%d\n", error);
        if (error) {
                if (rqp->sr_errclass == ERRDOS && rqp->sr_serror == ERRnoaccess)
                        error = EAUTH;
                goto bad;
        }
        vcp->vc_smbuid = rqp->sr_rpuid;
bad:
        kfree(encpass, M_SMBTEMP);
        kfree(pbuf, M_SMBTEMP);
        smb_rq_done(rqp);
        return error;
}

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

        if (vcp->vc_smbuid == SMB_UID_UNKNOWN)
                return 0;

        if (smb_smb_nomux(vcp, scred, __func__) != 0)
                return EINVAL;

        error = smb_rq_alloc(VCTOCP(vcp), SMB_COM_LOGOFF_ANDX, scred, &rqp);
        if (error)
                return error;
        mbp = &rqp->sr_rq;
        smb_rq_wstart(rqp);
        mb_put_uint8(mbp, 0xff);
        mb_put_uint8(mbp, 0);
        mb_put_uint16le(mbp, 0);
        smb_rq_wend(rqp);
        smb_rq_bstart(rqp);
        smb_rq_bend(rqp);
        error = smb_rq_simple(rqp);
        SMBSDEBUG("%d\n", error);
        smb_rq_done(rqp);
        return error;
}

static char smb_any_share[] = "?????";

static char *
smb_share_typename(int stype)
{
        char *pp;

        switch (stype) {
            case SMB_ST_DISK:
                pp = "A:";
                break;
            case SMB_ST_PRINTER:
                pp = smb_any_share;             /* can't use LPT: here... */
                break;
            case SMB_ST_PIPE:
                pp = "IPC";
                break;
            case SMB_ST_COMM:
                pp = "COMM";
                break;
            case SMB_ST_ANY:
            default:
                pp = smb_any_share;
                break;
        }
        return pp;
}

int
smb_smb_treeconnect(struct smb_share *ssp, struct smb_cred *scred)
{
        struct smb_vc *vcp;
        struct smb_rq rq, *rqp = &rq;
        struct mbchain *mbp;
        char *pp, *pbuf, *encpass;
        int error, plen, caseopt;

        ssp->ss_tid = SMB_TID_UNKNOWN;
        error = smb_rq_alloc(SSTOCP(ssp), SMB_COM_TREE_CONNECT_ANDX, scred, &rqp);
        if (error)
                return error;
        vcp = rqp->sr_vc;
        caseopt = SMB_CS_NONE;
        if (vcp->vc_sopt.sv_sm & SMB_SM_USER) {
                plen = 1;
                pp = "";
                pbuf = NULL;
                encpass = NULL;
        } else {
                pbuf = kmalloc(SMB_MAXPASSWORDLEN + 1, M_SMBTEMP, M_WAITOK);
                encpass = kmalloc(24, M_SMBTEMP, M_WAITOK);
                iconv_convstr(vcp->vc_toupper, pbuf, smb_share_getpass(ssp));
                iconv_convstr(vcp->vc_toserver, pbuf, pbuf);
                if (vcp->vc_sopt.sv_sm & SMB_SM_ENCRYPT) {
                        plen = 24;
                        smb_encrypt(pbuf, vcp->vc_ch, encpass);
                        pp = encpass;
                } else {
                        plen = strlen(pbuf) + 1;
                        pp = pbuf;
                }
        }
        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);
        mb_put_mem(mbp, pp, plen, MB_MSYSTEM);
        smb_put_dmem(mbp, vcp, "\\\\", 2, caseopt);
        pp = vcp->vc_srvname;
        smb_put_dmem(mbp, vcp, pp, strlen(pp), caseopt);
        smb_put_dmem(mbp, vcp, "\\", 1, caseopt);
        pp = ssp->ss_name;
        smb_put_dstring(mbp, vcp, pp, caseopt);
        pp = smb_share_typename(ssp->ss_type);
        smb_put_dstring(mbp, vcp, pp, caseopt);
        smb_rq_bend(rqp);
        error = smb_rq_simple(rqp);
        SMBSDEBUG("%d\n", error);
        if (error)
                goto bad;
        ssp->ss_tid = rqp->sr_rptid;
        ssp->ss_vcgenid = vcp->vc_genid;
        ssp->ss_flags |= SMBS_CONNECTED;
bad:
        if (encpass)
                kfree(encpass, M_SMBTEMP);
        if (pbuf)
                kfree(pbuf, M_SMBTEMP);
        smb_rq_done(rqp);
        return error;
}

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

        if (ssp->ss_tid == SMB_TID_UNKNOWN)
                return 0;
        error = smb_rq_alloc(SSTOCP(ssp), SMB_COM_TREE_DISCONNECT, scred, &rqp);
        if (error)
                return error;
        smb_rq_wstart(rqp);
        smb_rq_wend(rqp);
        smb_rq_bstart(rqp);
        smb_rq_bend(rqp);
        error = smb_rq_simple(rqp);
        SMBSDEBUG("%d\n", error);
        smb_rq_done(rqp);
        ssp->ss_tid = SMB_TID_UNKNOWN;
        return error;
}

static __inline int
smb_smb_read(struct smb_share *ssp, u_int16_t fid,
        int *len, int *rresid, struct uio *uio, struct smb_cred *scred)
{
        struct smb_rq *rqp;
        struct mbchain *mbp;
        struct mdchain *mdp;
        u_int16_t resid, bc;
        u_int8_t wc;
        int error, rlen, blksz;

        error = smb_rq_alloc(SSTOCP(ssp), SMB_COM_READ, scred, &rqp);
        if (error)
                return error;

        blksz = SSTOVC(ssp)->vc_txmax - SMB_HDRLEN - 16;
        rlen = *len = min(blksz, *len);

        smb_rq_getrequest(rqp, &mbp);
        smb_rq_wstart(rqp);
        mb_put_mem(mbp, (caddr_t)&fid, sizeof(fid), MB_MSYSTEM);
        mb_put_uint16le(mbp, rlen);
        mb_put_uint32le(mbp, uio->uio_offset);
        mb_put_uint16le(mbp, (unsigned short)szmin(uio->uio_resid, 0xffff));
        smb_rq_wend(rqp);
        smb_rq_bstart(rqp);
        smb_rq_bend(rqp);
        do {
                error = smb_rq_simple(rqp);
                if (error)
                        break;
                smb_rq_getreply(rqp, &mdp);
                md_get_uint8(mdp, &wc);
                if (wc != 5) {
                        error = EBADRPC;
                        break;
                }
                md_get_uint16le(mdp, &resid);
                md_get_mem(mdp, NULL, 4 * 2, MB_MSYSTEM);
                md_get_uint16le(mdp, &bc);
                md_get_uint8(mdp, NULL);                /* ignore buffer type */
                md_get_uint16le(mdp, &resid);
                if (resid == 0) {
                        *rresid = resid;
                        break;
                }
                error = md_get_uio(mdp, uio, resid);
                if (error)
                        break;
                *rresid = resid;
        } while(0);
        smb_rq_done(rqp);
        return error;
}

int
smb_read(struct smb_share *ssp, u_int16_t fid, struct uio *uio,
        struct smb_cred *scred)
{
        int len, resid;
        int error = 0;

        while (uio->uio_resid > 0) {
                if (uio->uio_resid > INT_MAX)
                        len = INT_MAX;
                else
                        len = (int)uio->uio_resid;
                error = smb_smb_read(ssp, fid, &len, &resid, uio, scred);
                if (error)
                        break;
                if (resid < len)
                        break;
        }
        return error;
}

static __inline int
smb_smb_write(struct smb_share *ssp, u_int16_t fid, int *len, int *rresid,
        struct uio *uio, struct smb_cred *scred)
{
        struct smb_rq *rqp;
        struct mbchain *mbp;
        struct mdchain *mdp;
        u_int16_t resid;
        u_int8_t wc;
        int error, blksz;

        /* write data must be real */
        KKASSERT(uio->uio_segflg != UIO_NOCOPY);

        blksz = SSTOVC(ssp)->vc_txmax - SMB_HDRLEN - 16;
        if (blksz > 0xffff)
                blksz = 0xffff;

        resid = *len = min(blksz, *len);

        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_mem(mbp, (caddr_t)&fid, sizeof(fid), MB_MSYSTEM);
        mb_put_uint16le(mbp, resid);
        mb_put_uint32le(mbp, uio->uio_offset);
        mb_put_uint16le(mbp, (unsigned short)szmin(uio->uio_resid, 0xffff));
        smb_rq_wend(rqp);
        smb_rq_bstart(rqp);
        mb_put_uint8(mbp, SMB_DT_DATA);
        mb_put_uint16le(mbp, resid);
        do {
                error = mb_put_uio(mbp, uio, resid);
                if (error)
                        break;
                smb_rq_bend(rqp);
                error = smb_rq_simple(rqp);
                if (error)
                        break;
                smb_rq_getreply(rqp, &mdp);
                md_get_uint8(mdp, &wc);
                if (wc != 1) {
                        error = EBADRPC;
                        break;
                }
                md_get_uint16le(mdp, &resid);
                *rresid = resid;
        } while(0);
        smb_rq_done(rqp);
        return error;
}

int
smb_write(struct smb_share *ssp, u_int16_t fid, struct uio *uio,
        struct smb_cred *scred)
{
        int error = 0, len, resid;
        struct uio olduio;

        olduio = *uio;
        while (uio->uio_resid > 0) {
                if (uio->uio_resid > INT_MAX)
                        len = INT_MAX;
                else
                        len = (int)uio->uio_resid;
                error = smb_smb_write(ssp, fid, &len, &resid, uio, scred);
                if (error)
                        break;
                if (resid < len) {
                        error = EIO;
                        break;
                }
        }
        if (error) {
                /*
                 * Errors can happen on the copyin, the rpc, etc.  So they
                 * imply resid is unreliable.  The only safe thing is
                 * to pretend zero bytes made it.  We needn't restore the
                 * iovs because callers don't depend on them in error
                 * paths - uio_resid and uio_offset are what matter.
                 */
                *uio = olduio;
        }
        return error;
}

int
smb_smb_echo(struct smb_vc *vcp, struct smb_cred *scred)
{
        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);
        smb_rq_wend(rqp);
        smb_rq_bstart(rqp);
        mb_put_uint32le(mbp, 0);
        smb_rq_bend(rqp);
        error = smb_rq_simple(rqp);
        SMBSDEBUG("%d\n", error);
        smb_rq_done(rqp);
        return error;
}