smbXcli: rework smbXcli_base.c to use smbXcli_conn/smbXcli_req

[Samba/gebeck_regimport.git] / libcli / smb / smbXcli_base.c

/*
   Unix SMB/CIFS implementation.
   Infrastructure for async SMB client requests
   Copyright (C) Volker Lendecke 2008
   Copyright (C) Stefan Metzmacher 2011

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "system/network.h"
#include "../lib/async_req/async_sock.h"
#include "../lib/util/tevent_ntstatus.h"
#include "../lib/util/tevent_unix.h"
#include "lib/util/util_net.h"
#include "../libcli/smb/smb_common.h"
#include "../libcli/smb/smb_seal.h"
#include "../libcli/smb/smb_signing.h"
#include "../libcli/smb/read_smb.h"
#include "smbXcli_base.h"
#include "librpc/ndr/libndr.h"

struct smbXcli_conn {
        int fd;
        struct sockaddr_storage local_ss;
        struct sockaddr_storage remote_ss;
        const char *remote_name;

        struct tevent_queue *outgoing;
        struct tevent_req **pending;
        struct tevent_req *read_smb_req;

        enum protocol_types protocol;
        bool allow_signing;
        bool desire_signing;
        bool mandatory_signing;

        /*
         * The incoming dispatch function should return:
         * - NT_STATUS_RETRY, if more incoming PDUs are expected.
         * - NT_STATUS_OK, if no more processing is desired, e.g.
         *                 the dispatch function called
         *                 tevent_req_done().
         * - All other return values disconnect the connection.
         */
        NTSTATUS (*dispatch_incoming)(struct smbXcli_conn *conn,
                                      TALLOC_CTX *tmp_mem,
                                      uint8_t *inbuf);

        struct {
                struct {
                        uint32_t capabilities;
                        uint32_t max_xmit;
                } client;

                struct {
                        uint32_t capabilities;
                        uint32_t max_xmit;
                        uint16_t max_mux;
                        uint16_t security_mode;
                        bool readbraw;
                        bool writebraw;
                        bool lockread;
                        bool writeunlock;
                        uint32_t session_key;
                        struct GUID guid;
                        DATA_BLOB gss_blob;
                        uint8_t challenge[8];
                        const char *workgroup;
                        int time_zone;
                        NTTIME system_time;
                } server;

                uint32_t capabilities;
                uint32_t max_xmit;

                uint16_t mid;

                struct smb_signing_state *signing;
                struct smb_trans_enc_state *trans_enc;
        } smb1;
};

struct smbXcli_req_state {
        struct tevent_context *ev;
        struct smbXcli_conn *conn;

        uint8_t length_hdr[4];

        bool one_way;

        uint8_t *inbuf;

        struct {
                /* Space for the header including the wct */
                uint8_t hdr[HDR_VWV];

                /*
                 * For normal requests, smb1cli_req_send chooses a mid.
                 * SecondaryV trans requests need to use the mid of the primary
                 * request, so we need a place to store it.
                 * Assume it is set if != 0.
                 */
                uint16_t mid;

                uint16_t *vwv;
                uint8_t bytecount_buf[2];

#define MAX_SMB_IOV 5
                /* length_hdr, hdr, words, byte_count, buffers */
                struct iovec iov[1 + 3 + MAX_SMB_IOV];
                int iov_count;

                uint32_t seqnum;
                int chain_num;
                int chain_length;
                struct tevent_req **chained_requests;
        } smb1;
};

static int smbXcli_conn_destructor(struct smbXcli_conn *conn)
{
        /*
         * NT_STATUS_OK, means we do not notify the callers
         */
        smbXcli_conn_disconnect(conn, NT_STATUS_OK);

        if (conn->smb1.trans_enc) {
                common_free_encryption_state(&conn->smb1.trans_enc);
        }

        return 0;
}

struct smbXcli_conn *smbXcli_conn_create(TALLOC_CTX *mem_ctx,
                                         int fd,
                                         const char *remote_name,
                                         enum smb_signing_setting signing_state,
                                         uint32_t smb1_capabilities)
{
        struct smbXcli_conn *conn = NULL;
        void *ss = NULL;
        struct sockaddr *sa = NULL;
        socklen_t sa_length;
        int ret;

        conn = talloc_zero(mem_ctx, struct smbXcli_conn);
        if (!conn) {
                return NULL;
        }

        conn->remote_name = talloc_strdup(conn, remote_name);
        if (conn->remote_name == NULL) {
                goto error;
        }

        conn->fd = fd;

        ss = (void *)&conn->local_ss;
        sa = (struct sockaddr *)ss;
        sa_length = sizeof(conn->local_ss);
        ret = getsockname(fd, sa, &sa_length);
        if (ret == -1) {
                goto error;
        }
        ss = (void *)&conn->remote_ss;
        sa = (struct sockaddr *)ss;
        sa_length = sizeof(conn->remote_ss);
        ret = getpeername(fd, sa, &sa_length);
        if (ret == -1) {
                goto error;
        }

        conn->outgoing = tevent_queue_create(conn, "smbXcli_outgoing");
        if (conn->outgoing == NULL) {
                goto error;
        }
        conn->pending = NULL;

        conn->protocol = PROTOCOL_NONE;

        switch (signing_state) {
        case SMB_SIGNING_OFF:
                /* never */
                conn->allow_signing = false;
                conn->desire_signing = false;
                conn->mandatory_signing = false;
                break;
        case SMB_SIGNING_DEFAULT:
        case SMB_SIGNING_IF_REQUIRED:
                /* if the server requires it */
                conn->allow_signing = true;
                conn->desire_signing = false;
                conn->mandatory_signing = false;
                break;
        case SMB_SIGNING_REQUIRED:
                /* always */
                conn->allow_signing = true;
                conn->desire_signing = true;
                conn->mandatory_signing = true;
                break;
        }

        conn->smb1.client.capabilities = smb1_capabilities;
        conn->smb1.client.max_xmit = UINT16_MAX;

        conn->smb1.capabilities = conn->smb1.client.capabilities;
        conn->smb1.max_xmit = 1024;

        conn->smb1.mid = 1;

        /* initialise signing */
        conn->smb1.signing = smb_signing_init(conn,
                                              conn->allow_signing,
                                              conn->desire_signing,
                                              conn->mandatory_signing);
        if (!conn->smb1.signing) {
                goto error;
        }

        talloc_set_destructor(conn, smbXcli_conn_destructor);
        return conn;

 error:
        TALLOC_FREE(conn);
        return NULL;
}

bool smbXcli_conn_is_connected(struct smbXcli_conn *conn)
{
        if (conn == NULL) {
                return false;
        }

        if (conn->fd == -1) {
                return false;
        }

        return true;
}

enum protocol_types smbXcli_conn_protocol(struct smbXcli_conn *conn)
{
        return conn->protocol;
}

bool smbXcli_conn_use_unicode(struct smbXcli_conn *conn)
{
        if (conn->protocol >= PROTOCOL_SMB2_02) {
                return true;
        }

        if (conn->smb1.capabilities & CAP_UNICODE) {
                return true;
        }

        return false;
}

void smbXcli_conn_set_sockopt(struct smbXcli_conn *conn, const char *options)
{
        set_socket_options(conn->fd, options);
}

const struct sockaddr_storage *smbXcli_conn_local_sockaddr(struct smbXcli_conn *conn)
{
        return &conn->local_ss;
}

const struct sockaddr_storage *smbXcli_conn_remote_sockaddr(struct smbXcli_conn *conn)
{
        return &conn->remote_ss;
}

const char *smbXcli_conn_remote_name(struct smbXcli_conn *conn)
{
        return conn->remote_name;
}

bool smb1cli_conn_activate_signing(struct smbXcli_conn *conn,
                                   const DATA_BLOB user_session_key,
                                   const DATA_BLOB response)
{
        return smb_signing_activate(conn->smb1.signing,
                                    user_session_key,
                                    response);
}

bool smb1cli_conn_check_signing(struct smbXcli_conn *conn,
                                const uint8_t *buf, uint32_t seqnum)
{
        return smb_signing_check_pdu(conn->smb1.signing, buf, seqnum);
}

bool smb1cli_conn_signing_is_active(struct smbXcli_conn *conn)
{
        return smb_signing_is_active(conn->smb1.signing);
}

void smb1cli_conn_set_encryption(struct smbXcli_conn *conn,
                                 struct smb_trans_enc_state *es)
{
        /* Replace the old state, if any. */
        if (conn->smb1.trans_enc) {
                common_free_encryption_state(&conn->smb1.trans_enc);
        }
        conn->smb1.trans_enc = es;
}

bool smb1cli_conn_encryption_on(struct smbXcli_conn *conn)
{
        return common_encryption_on(conn->smb1.trans_enc);
}


static NTSTATUS smb1cli_pull_raw_error(const uint8_t *buf)
{
        const uint8_t *hdr = buf + NBT_HDR_SIZE;
        uint32_t flags2 = SVAL(hdr, HDR_FLG2);
        NTSTATUS status = NT_STATUS(IVAL(hdr, HDR_RCLS));

        if (NT_STATUS_IS_OK(status)) {
                return NT_STATUS_OK;
        }

        if (flags2 & FLAGS2_32_BIT_ERROR_CODES) {
                return status;
        }

        return NT_STATUS_DOS(CVAL(hdr, HDR_RCLS), SVAL(hdr, HDR_ERR));
}

/**
 * Figure out if there is an andx command behind the current one
 * @param[in] buf       The smb buffer to look at
 * @param[in] ofs       The offset to the wct field that is followed by the cmd
 * @retval Is there a command following?
 */

static bool smb1cli_have_andx_command(const uint8_t *buf,
                                      uint16_t ofs,
                                      uint8_t cmd)
{
        uint8_t wct;
        size_t buflen = talloc_get_size(buf);

        if (!smb1cli_is_andx_req(cmd)) {
                return false;
        }

        if ((ofs == buflen-1) || (ofs == buflen)) {
                return false;
        }

        wct = CVAL(buf, ofs);
        if (wct < 2) {
                /*
                 * Not enough space for the command and a following pointer
                 */
                return false;
        }
        return (CVAL(buf, ofs+1) != 0xff);
}

/**
 * Is the SMB command able to hold an AND_X successor
 * @param[in] cmd       The SMB command in question
 * @retval Can we add a chained request after "cmd"?
 */
bool smb1cli_is_andx_req(uint8_t cmd)
{
        switch (cmd) {
        case SMBtconX:
        case SMBlockingX:
        case SMBopenX:
        case SMBreadX:
        case SMBwriteX:
        case SMBsesssetupX:
        case SMBulogoffX:
        case SMBntcreateX:
                return true;
                break;
        default:
                break;
        }

        return false;
}

static uint16_t smb1cli_alloc_mid(struct smbXcli_conn *conn)
{
        size_t num_pending = talloc_array_length(conn->pending);
        uint16_t result;

        while (true) {
                size_t i;

                result = conn->smb1.mid++;
                if ((result == 0) || (result == 0xffff)) {
                        continue;
                }

                for (i=0; i<num_pending; i++) {
                        if (result == smb1cli_req_mid(conn->pending[i])) {
                                break;
                        }
                }

                if (i == num_pending) {
                        return result;
                }
        }
}

void smbXcli_req_unset_pending(struct tevent_req *req)
{
        struct smbXcli_req_state *state =
                tevent_req_data(req,
                struct smbXcli_req_state);
        struct smbXcli_conn *conn = state->conn;
        size_t num_pending = talloc_array_length(conn->pending);
        size_t i;

        if (state->smb1.mid != 0) {
                /*
                 * This is a [nt]trans[2] request which waits
                 * for more than one reply.
                 */
                return;
        }

        talloc_set_destructor(req, NULL);

        if (num_pending == 1) {
                /*
                 * The pending read_smb tevent_req is a child of
                 * conn->pending. So if nothing is pending anymore, we need to
                 * delete the socket read fde.
                 */
                TALLOC_FREE(conn->pending);
                conn->read_smb_req = NULL;
                return;
        }

        for (i=0; i<num_pending; i++) {
                if (req == conn->pending[i]) {
                        break;
                }
        }
        if (i == num_pending) {
                /*
                 * Something's seriously broken. Just returning here is the
                 * right thing nevertheless, the point of this routine is to
                 * remove ourselves from conn->pending.
                 */
                return;
        }

        /*
         * Remove ourselves from the conn->pending array
         */
        for (; i < (num_pending - 1); i++) {
                conn->pending[i] = conn->pending[i+1];
        }

        /*
         * No NULL check here, we're shrinking by sizeof(void *), and
         * talloc_realloc just adjusts the size for this.
         */
        conn->pending = talloc_realloc(NULL, conn->pending, struct tevent_req *,
                                       num_pending - 1);
        return;
}

static int smbXcli_req_destructor(struct tevent_req *req)
{
        struct smbXcli_req_state *state =
                tevent_req_data(req,
                struct smbXcli_req_state);

        /*
         * Make sure we really remove it from
         * the pending array on destruction.
         */
        state->smb1.mid = 0;
        smbXcli_req_unset_pending(req);
        return 0;
}

static bool smbXcli_conn_receive_next(struct smbXcli_conn *conn);

bool smbXcli_req_set_pending(struct tevent_req *req)
{
        struct smbXcli_req_state *state =
                tevent_req_data(req,
                struct smbXcli_req_state);
        struct smbXcli_conn *conn;
        struct tevent_req **pending;
        size_t num_pending;

        conn = state->conn;

        if (!smbXcli_conn_is_connected(conn)) {
                return false;
        }

        num_pending = talloc_array_length(conn->pending);

        pending = talloc_realloc(conn, conn->pending, struct tevent_req *,
                                 num_pending+1);
        if (pending == NULL) {
                return false;
        }
        pending[num_pending] = req;
        conn->pending = pending;
        talloc_set_destructor(req, smbXcli_req_destructor);

        if (!smbXcli_conn_receive_next(conn)) {
                /*
                 * the caller should notify the current request
                 *
                 * And all other pending requests get notified
                 * by smbXcli_conn_disconnect().
                 */
                smbXcli_req_unset_pending(req);
                smbXcli_conn_disconnect(conn, NT_STATUS_NO_MEMORY);
                return false;
        }

        return true;
}

static void smbXcli_conn_received(struct tevent_req *subreq);

static bool smbXcli_conn_receive_next(struct smbXcli_conn *conn)
{
        size_t num_pending = talloc_array_length(conn->pending);
        struct tevent_req *req;
        struct smbXcli_req_state *state;

        if (conn->read_smb_req != NULL) {
                return true;
        }

        if (num_pending == 0) {
                return true;
        }

        req = conn->pending[0];
        state = tevent_req_data(req, struct smbXcli_req_state);

        /*
         * We're the first ones, add the read_smb request that waits for the
         * answer from the server
         */
        conn->read_smb_req = read_smb_send(conn->pending, state->ev, conn->fd);
        if (conn->read_smb_req == NULL) {
                return false;
        }
        tevent_req_set_callback(conn->read_smb_req, smbXcli_conn_received, conn);
        return true;
}

void smbXcli_conn_disconnect(struct smbXcli_conn *conn, NTSTATUS status)
{
        if (conn->fd != -1) {
                close(conn->fd);
        }
        conn->fd = -1;

        /*
         * Cancel all pending requests. We do not do a for-loop walking
         * conn->pending because that array changes in
         * smbXcli_req_unset_pending.
         */
        while (talloc_array_length(conn->pending) > 0) {
                struct tevent_req *req;
                struct smbXcli_req_state *state;

                req = conn->pending[0];
                state = tevent_req_data(req, struct smbXcli_req_state);

                /*
                 * We're dead. No point waiting for trans2
                 * replies.
                 */
                state->smb1.mid = 0;

                smbXcli_req_unset_pending(req);

                if (NT_STATUS_IS_OK(status)) {
                        /* do not notify the callers */
                        continue;
                }

                /*
                 * we need to defer the callback, because we may notify more
                 * then one caller.
                 */
                tevent_req_defer_callback(req, state->ev);
                tevent_req_nterror(req, status);
        }
}

/*
 * Fetch a smb request's mid. Only valid after the request has been sent by
 * smb1cli_req_send().
 */
uint16_t smb1cli_req_mid(struct tevent_req *req)
{
        struct smbXcli_req_state *state =
                tevent_req_data(req,
                struct smbXcli_req_state);

        if (state->smb1.mid != 0) {
                return state->smb1.mid;
        }

        return SVAL(state->smb1.hdr, HDR_MID);
}

void smb1cli_req_set_mid(struct tevent_req *req, uint16_t mid)
{
        struct smbXcli_req_state *state =
                tevent_req_data(req,
                struct smbXcli_req_state);

        state->smb1.mid = mid;
}

uint32_t smb1cli_req_seqnum(struct tevent_req *req)
{
        struct smbXcli_req_state *state =
                tevent_req_data(req,
                struct smbXcli_req_state);

        return state->smb1.seqnum;
}

void smb1cli_req_set_seqnum(struct tevent_req *req, uint32_t seqnum)
{
        struct smbXcli_req_state *state =
                tevent_req_data(req,
                struct smbXcli_req_state);

        state->smb1.seqnum = seqnum;
}

static size_t smbXcli_iov_len(const struct iovec *iov, int count)
{
        size_t result = 0;
        int i;
        for (i=0; i<count; i++) {
                result += iov[i].iov_len;
        }
        return result;
}

static uint8_t *smbXcli_iov_concat(TALLOC_CTX *mem_ctx,
                                   const struct iovec *iov,
                                   int count)
{
        size_t len = smbXcli_iov_len(iov, count);
        size_t copied;
        uint8_t *buf;
        int i;

        buf = talloc_array(mem_ctx, uint8_t, len);
        if (buf == NULL) {
                return NULL;
        }
        copied = 0;
        for (i=0; i<count; i++) {
                memcpy(buf+copied, iov[i].iov_base, iov[i].iov_len);
                copied += iov[i].iov_len;
        }
        return buf;
}

struct tevent_req *smb1cli_req_create(TALLOC_CTX *mem_ctx,
                                      struct tevent_context *ev,
                                      struct smbXcli_conn *conn,
                                      uint8_t smb_command,
                                      uint8_t additional_flags,
                                      uint8_t clear_flags,
                                      uint16_t additional_flags2,
                                      uint16_t clear_flags2,
                                      uint32_t timeout_msec,
                                      uint32_t pid,
                                      uint16_t tid,
                                      uint16_t uid,
                                      uint8_t wct, uint16_t *vwv,
                                      int iov_count,
                                      struct iovec *bytes_iov)
{
        struct tevent_req *req;
        struct smbXcli_req_state *state;
        uint8_t flags = 0;
        uint16_t flags2 = 0;

        if (iov_count > MAX_SMB_IOV) {
                /*
                 * Should not happen :-)
                 */
                return NULL;
        }

        req = tevent_req_create(mem_ctx, &state,
                                struct smbXcli_req_state);
        if (req == NULL) {
                return NULL;
        }
        state->ev = ev;
        state->conn = conn;

        if (conn->protocol >= PROTOCOL_LANMAN1) {
                flags |= FLAG_CASELESS_PATHNAMES;
                flags |= FLAG_CANONICAL_PATHNAMES;
        }

        if (conn->protocol >= PROTOCOL_LANMAN2) {
                flags2 |= FLAGS2_LONG_PATH_COMPONENTS;
                flags2 |= FLAGS2_EXTENDED_ATTRIBUTES;
        }

        if (conn->protocol >= PROTOCOL_NT1) {
                if (conn->smb1.capabilities & CAP_UNICODE) {
                        flags2 |= FLAGS2_UNICODE_STRINGS;
                }
                if (conn->smb1.capabilities & CAP_STATUS32) {
                        flags2 |= FLAGS2_32_BIT_ERROR_CODES;
                }
                if (conn->smb1.capabilities & CAP_EXTENDED_SECURITY) {
                        flags2 |= FLAGS2_EXTENDED_SECURITY;
                }
        }

        flags |= additional_flags;
        flags &= ~clear_flags;
        flags2 |= additional_flags2;
        flags2 &= ~clear_flags2;

        SIVAL(state->smb1.hdr, 0,           SMB_MAGIC);
        SCVAL(state->smb1.hdr, HDR_COM,     smb_command);
        SIVAL(state->smb1.hdr, HDR_RCLS,    NT_STATUS_V(NT_STATUS_OK));
        SCVAL(state->smb1.hdr, HDR_FLG,     flags);
        SSVAL(state->smb1.hdr, HDR_FLG2,    flags2);
        SSVAL(state->smb1.hdr, HDR_PIDHIGH, pid >> 16);
        SSVAL(state->smb1.hdr, HDR_TID,     tid);
        SSVAL(state->smb1.hdr, HDR_PID,     pid);
        SSVAL(state->smb1.hdr, HDR_UID,     uid);
        SSVAL(state->smb1.hdr, HDR_MID,     0); /* this comes later */
        SSVAL(state->smb1.hdr, HDR_WCT,     wct);

        state->smb1.vwv = vwv;

        SSVAL(state->smb1.bytecount_buf, 0, smbXcli_iov_len(bytes_iov, iov_count));

        state->smb1.iov[0].iov_base = (void *)state->length_hdr;
        state->smb1.iov[0].iov_len  = sizeof(state->length_hdr);
        state->smb1.iov[1].iov_base = (void *)state->smb1.hdr;
        state->smb1.iov[1].iov_len  = sizeof(state->smb1.hdr);
        state->smb1.iov[2].iov_base = (void *)state->smb1.vwv;
        state->smb1.iov[2].iov_len  = wct * sizeof(uint16_t);
        state->smb1.iov[3].iov_base = (void *)state->smb1.bytecount_buf;
        state->smb1.iov[3].iov_len  = sizeof(uint16_t);

        if (iov_count != 0) {
                memcpy(&state->smb1.iov[4], bytes_iov,
                       iov_count * sizeof(*bytes_iov));
        }
        state->smb1.iov_count = iov_count + 4;

        if (timeout_msec > 0) {
                struct timeval endtime;

                endtime = timeval_current_ofs_msec(timeout_msec);
                if (!tevent_req_set_endtime(req, ev, endtime)) {
                        return req;
                }
        }

        switch (smb_command) {
        case SMBtranss:
        case SMBtranss2:
        case SMBnttranss:
        case SMBntcancel:
                state->one_way = true;
                break;
        case SMBlockingX:
                if ((wct == 8) &&
                    (CVAL(vwv+3, 0) == LOCKING_ANDX_OPLOCK_RELEASE)) {
                        state->one_way = true;
                }
                break;
        }

        return req;
}

static NTSTATUS smb1cli_conn_signv(struct smbXcli_conn *conn,
                                   struct iovec *iov, int iov_count,
                                   uint32_t *seqnum)
{
        uint8_t *buf;

        /*
         * Obvious optimization: Make cli_calculate_sign_mac work with struct
         * iovec directly. MD5Update would do that just fine.
         */

        if (iov_count < 4) {
                return NT_STATUS_INVALID_PARAMETER_MIX;
        }
        if (iov[0].iov_len != NBT_HDR_SIZE) {
                return NT_STATUS_INVALID_PARAMETER_MIX;
        }
        if (iov[1].iov_len != (MIN_SMB_SIZE-sizeof(uint16_t))) {
                return NT_STATUS_INVALID_PARAMETER_MIX;
        }
        if (iov[2].iov_len > (0xFF * sizeof(uint16_t))) {
                return NT_STATUS_INVALID_PARAMETER_MIX;
        }
        if (iov[3].iov_len != sizeof(uint16_t)) {
                return NT_STATUS_INVALID_PARAMETER_MIX;
        }

        buf = smbXcli_iov_concat(talloc_tos(), iov, iov_count);
        if (buf == NULL) {
                return NT_STATUS_NO_MEMORY;
        }

        *seqnum = smb_signing_next_seqnum(conn->smb1.signing, false);
        smb_signing_sign_pdu(conn->smb1.signing, buf, *seqnum);
        memcpy(iov[1].iov_base, buf+4, iov[1].iov_len);

        TALLOC_FREE(buf);
        return NT_STATUS_OK;
}

static void smb1cli_req_writev_done(struct tevent_req *subreq);
static NTSTATUS smb1cli_conn_dispatch_incoming(struct smbXcli_conn *conn,
                                               TALLOC_CTX *tmp_mem,
                                               uint8_t *inbuf);

static NTSTATUS smb1cli_req_writev_submit(struct tevent_req *req,
                                          struct smbXcli_req_state *state,
                                          struct iovec *iov, int iov_count)
{
        struct tevent_req *subreq;
        NTSTATUS status;
        uint16_t mid;

        if (!smbXcli_conn_is_connected(state->conn)) {
                return NT_STATUS_CONNECTION_DISCONNECTED;
        }

        if (state->conn->protocol > PROTOCOL_NT1) {
                return NT_STATUS_REVISION_MISMATCH;
        }

        if (iov_count < 4) {
                return NT_STATUS_INVALID_PARAMETER_MIX;
        }
        if (iov[0].iov_len != NBT_HDR_SIZE) {
                return NT_STATUS_INVALID_PARAMETER_MIX;
        }
        if (iov[1].iov_len != (MIN_SMB_SIZE-sizeof(uint16_t))) {
                return NT_STATUS_INVALID_PARAMETER_MIX;
        }
        if (iov[2].iov_len > (0xFF * sizeof(uint16_t))) {
                return NT_STATUS_INVALID_PARAMETER_MIX;
        }
        if (iov[3].iov_len != sizeof(uint16_t)) {
                return NT_STATUS_INVALID_PARAMETER_MIX;
        }

        if (state->smb1.mid != 0) {
                mid = state->smb1.mid;
        } else {
                mid = smb1cli_alloc_mid(state->conn);
        }
        SSVAL(iov[1].iov_base, HDR_MID, mid);

        _smb_setlen_nbt(iov[0].iov_base, smbXcli_iov_len(&iov[1], iov_count-1));

        status = smb1cli_conn_signv(state->conn, iov, iov_count,
                                    &state->smb1.seqnum);

        if (!NT_STATUS_IS_OK(status)) {
                return status;
        }

        /*
         * If we supported multiple encrytion contexts
         * here we'd look up based on tid.
         */
        if (common_encryption_on(state->conn->smb1.trans_enc)) {
                char *buf, *enc_buf;

                buf = (char *)smbXcli_iov_concat(talloc_tos(), iov, iov_count);
                if (buf == NULL) {
                        return NT_STATUS_NO_MEMORY;
                }
                status = common_encrypt_buffer(state->conn->smb1.trans_enc,
                                               (char *)buf, &enc_buf);
                TALLOC_FREE(buf);
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(0, ("Error in encrypting client message: %s\n",
                                  nt_errstr(status)));
                        return status;
                }
                buf = (char *)talloc_memdup(state, enc_buf,
                                            smb_len_nbt(enc_buf)+4);
                SAFE_FREE(enc_buf);
                if (buf == NULL) {
                        return NT_STATUS_NO_MEMORY;
                }
                iov[0].iov_base = (void *)buf;
                iov[0].iov_len = talloc_get_size(buf);
                iov_count = 1;
        }

        if (state->conn->dispatch_incoming == NULL) {
                state->conn->dispatch_incoming = smb1cli_conn_dispatch_incoming;
        }

        subreq = writev_send(state, state->ev, state->conn->outgoing,
                             state->conn->fd, false, iov, iov_count);
        if (subreq == NULL) {
                return NT_STATUS_NO_MEMORY;
        }
        tevent_req_set_callback(subreq, smb1cli_req_writev_done, req);
        return NT_STATUS_OK;
}

struct tevent_req *smb1cli_req_send(TALLOC_CTX *mem_ctx,
                                    struct tevent_context *ev,
                                    struct smbXcli_conn *conn,
                                    uint8_t smb_command,
                                    uint8_t additional_flags,
                                    uint8_t clear_flags,
                                    uint16_t additional_flags2,
                                    uint16_t clear_flags2,
                                    uint32_t timeout_msec,
                                    uint32_t pid,
                                    uint16_t tid,
                                    uint16_t uid,
                                    uint8_t wct, uint16_t *vwv,
                                    uint32_t num_bytes,
                                    const uint8_t *bytes)
{
        struct tevent_req *req;
        struct iovec iov;
        NTSTATUS status;

        iov.iov_base = discard_const_p(void, bytes);
        iov.iov_len = num_bytes;

        req = smb1cli_req_create(mem_ctx, ev, conn, smb_command,
                                 additional_flags, clear_flags,
                                 additional_flags2, clear_flags2,
                                 timeout_msec,
                                 pid, tid, uid,
                                 wct, vwv, 1, &iov);
        if (req == NULL) {
                return NULL;
        }
        if (!tevent_req_is_in_progress(req)) {
                return tevent_req_post(req, ev);
        }
        status = smb1cli_req_chain_submit(&req, 1);
        if (tevent_req_nterror(req, status)) {
                return tevent_req_post(req, ev);
        }
        return req;
}

static void smb1cli_req_writev_done(struct tevent_req *subreq)
{
        struct tevent_req *req =
                tevent_req_callback_data(subreq,
                struct tevent_req);
        struct smbXcli_req_state *state =
                tevent_req_data(req,
                struct smbXcli_req_state);
        ssize_t nwritten;
        int err;

        nwritten = writev_recv(subreq, &err);
        TALLOC_FREE(subreq);
        if (nwritten == -1) {
                NTSTATUS status = map_nt_error_from_unix_common(err);
                smbXcli_conn_disconnect(state->conn, status);
                return;
        }

        if (state->one_way) {
                state->inbuf = NULL;
                tevent_req_done(req);
                return;
        }

        if (!smbXcli_req_set_pending(req)) {
                tevent_req_nterror(req, NT_STATUS_NO_MEMORY);
                return;
        }
}

static void smbXcli_conn_received(struct tevent_req *subreq)
{
        struct smbXcli_conn *conn =
                tevent_req_callback_data(subreq,
                struct smbXcli_conn);
        TALLOC_CTX *frame = talloc_stackframe();
        NTSTATUS status;
        uint8_t *inbuf;
        ssize_t received;
        int err;

        if (subreq != conn->read_smb_req) {
                DEBUG(1, ("Internal error: cli_smb_received called with "
                          "unexpected subreq\n"));
                status = NT_STATUS_INTERNAL_ERROR;
                smbXcli_conn_disconnect(conn, status);
                TALLOC_FREE(frame);
                return;
        }
        conn->read_smb_req = NULL;

        received = read_smb_recv(subreq, frame, &inbuf, &err);
        TALLOC_FREE(subreq);
        if (received == -1) {
                status = map_nt_error_from_unix_common(err);
                smbXcli_conn_disconnect(conn, status);
                TALLOC_FREE(frame);
                return;
        }

        status = conn->dispatch_incoming(conn, frame, inbuf);
        TALLOC_FREE(frame);
        if (NT_STATUS_IS_OK(status)) {
                /*
                 * We should not do any more processing
                 * as the dispatch function called
                 * tevent_req_done().
                 */
                return;
        } else if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
                /*
                 * We got an error, so notify all pending requests
                 */
                smbXcli_conn_disconnect(conn, status);
                return;
        }

        /*
         * We got NT_STATUS_RETRY, so we may ask for a
         * next incoming pdu.
         */
        if (!smbXcli_conn_receive_next(conn)) {
                smbXcli_conn_disconnect(conn, NT_STATUS_NO_MEMORY);
        }
}

static NTSTATUS smb1cli_conn_dispatch_incoming(struct smbXcli_conn *conn,
                                               TALLOC_CTX *tmp_mem,
                                               uint8_t *inbuf)
{
        struct tevent_req *req;
        struct smbXcli_req_state *state;
        NTSTATUS status;
        size_t num_pending;
        size_t i;
        uint16_t mid;
        bool oplock_break;
        const uint8_t *inhdr = inbuf + NBT_HDR_SIZE;

        if ((IVAL(inhdr, 0) != SMB_MAGIC) /* 0xFF"SMB" */
            && (SVAL(inhdr, 0) != 0x45ff)) /* 0xFF"E" */ {
                DEBUG(10, ("Got non-SMB PDU\n"));
                return NT_STATUS_INVALID_NETWORK_RESPONSE;
        }

        /*
         * If we supported multiple encrytion contexts
         * here we'd look up based on tid.
         */
        if (common_encryption_on(conn->smb1.trans_enc)
            && (CVAL(inbuf, 0) == 0)) {
                uint16_t enc_ctx_num;

                status = get_enc_ctx_num(inbuf, &enc_ctx_num);
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(10, ("get_enc_ctx_num returned %s\n",
                                   nt_errstr(status)));
                        return status;
                }

                if (enc_ctx_num != conn->smb1.trans_enc->enc_ctx_num) {
                        DEBUG(10, ("wrong enc_ctx %d, expected %d\n",
                                   enc_ctx_num,
                                   conn->smb1.trans_enc->enc_ctx_num));
                        return NT_STATUS_INVALID_HANDLE;
                }

                status = common_decrypt_buffer(conn->smb1.trans_enc,
                                               (char *)inbuf);
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(10, ("common_decrypt_buffer returned %s\n",
                                   nt_errstr(status)));
                        return status;
                }
        }

        mid = SVAL(inhdr, HDR_MID);
        num_pending = talloc_array_length(conn->pending);

        for (i=0; i<num_pending; i++) {
                if (mid == smb1cli_req_mid(conn->pending[i])) {
                        break;
                }
        }
        if (i == num_pending) {
                /* Dump unexpected reply */
                return NT_STATUS_RETRY;
        }

        oplock_break = false;

        if (mid == 0xffff) {
                /*
                 * Paranoia checks that this is really an oplock break request.
                 */
                oplock_break = (smb_len_nbt(inbuf) == 51); /* hdr + 8 words */
                oplock_break &= ((CVAL(inhdr, HDR_FLG) & FLAG_REPLY) == 0);
                oplock_break &= (CVAL(inhdr, HDR_COM) == SMBlockingX);
                oplock_break &= (SVAL(inhdr, HDR_VWV+VWV(6)) == 0);
                oplock_break &= (SVAL(inhdr, HDR_VWV+VWV(7)) == 0);

                if (!oplock_break) {
                        /* Dump unexpected reply */
                        return NT_STATUS_RETRY;
                }
        }

        req = conn->pending[i];
        state = tevent_req_data(req, struct smbXcli_req_state);

        if (!oplock_break /* oplock breaks are not signed */
            && !smb_signing_check_pdu(conn->smb1.signing,
                                      inbuf, state->smb1.seqnum+1)) {
                DEBUG(10, ("cli_check_sign_mac failed\n"));
                return NT_STATUS_ACCESS_DENIED;
        }

        if (state->smb1.chained_requests != NULL) {
                struct tevent_req **chain = talloc_move(tmp_mem,
                                            &state->smb1.chained_requests);
                size_t num_chained = talloc_array_length(chain);

                /*
                 * We steal the inbuf to the chain,
                 * so that it will stay until all
                 * requests of the chain are finished.
                 *
                 * Each requests in the chain will
                 * hold a talloc reference to the chain.
                 * This way we do not expose the talloc_reference()
                 * behavior to the callers.
                 */
                talloc_steal(chain, inbuf);

                for (i=0; i<num_chained; i++) {
                        struct tevent_req **ref;

                        req = chain[i];
                        state = tevent_req_data(req, struct smbXcli_req_state);

                        smbXcli_req_unset_pending(req);

                        /*
                         * as we finish multiple requests here
                         * we need to defer the callbacks as
                         * they could destroy our current stack state.
                         */
                        tevent_req_defer_callback(req, state->ev);

                        ref = talloc_reference(state, chain);
                        if (tevent_req_nomem(ref, req)) {
                                continue;
                        }

                        state->inbuf = inbuf;
                        state->smb1.chain_num = i;
                        state->smb1.chain_length = num_chained;

                        tevent_req_done(req);
                }
                return NT_STATUS_RETRY;
        }

        smbXcli_req_unset_pending(req);

        state->inbuf = talloc_move(state, &inbuf);
        state->smb1.chain_num = 0;
        state->smb1.chain_length = 1;

        if (talloc_array_length(conn->pending) == 0) {
                tevent_req_done(req);
                return NT_STATUS_OK;
        }

        tevent_req_defer_callback(req, state->ev);
        tevent_req_done(req);
        return NT_STATUS_RETRY;
}

NTSTATUS smb1cli_req_recv(struct tevent_req *req,
                          TALLOC_CTX *mem_ctx, uint8_t **pinbuf,
                          uint8_t min_wct, uint8_t *pwct, uint16_t **pvwv,
                          uint32_t *pnum_bytes, uint8_t **pbytes)
{
        struct smbXcli_req_state *state =
                tevent_req_data(req,
                struct smbXcli_req_state);
        NTSTATUS status = NT_STATUS_OK;
        uint8_t cmd, wct;
        uint16_t num_bytes;
        size_t wct_ofs, bytes_offset;
        int i;

        if (tevent_req_is_nterror(req, &status)) {
                return status;
        }

        if (state->inbuf == NULL) {
                if (min_wct != 0) {
                        return NT_STATUS_INVALID_NETWORK_RESPONSE;
                }
                if (pinbuf) {
                        *pinbuf = NULL;
                }
                if (pwct) {
                        *pwct = 0;
                }
                if (pvwv) {
                        *pvwv = NULL;
                }
                if (pnum_bytes) {
                        *pnum_bytes = 0;
                }
                if (pbytes) {
                        *pbytes = NULL;
                }
                /* This was a request without a reply */
                return NT_STATUS_OK;
        }

        wct_ofs = NBT_HDR_SIZE + HDR_WCT;
        cmd = CVAL(state->inbuf, NBT_HDR_SIZE + HDR_COM);

        for (i=0; i<state->smb1.chain_num; i++) {
                if (i < state->smb1.chain_num-1) {
                        if (cmd == 0xff) {
                                return NT_STATUS_REQUEST_ABORTED;
                        }
                        if (!smb1cli_is_andx_req(cmd)) {
                                return NT_STATUS_INVALID_NETWORK_RESPONSE;
                        }
                }

                if (!smb1cli_have_andx_command(state->inbuf, wct_ofs, cmd)) {
                        /*
                         * This request was not completed because a previous
                         * request in the chain had received an error.
                         */
                        return NT_STATUS_REQUEST_ABORTED;
                }

                cmd = CVAL(state->inbuf, wct_ofs + 1);
                wct_ofs = SVAL(state->inbuf, wct_ofs + 3);

                /*
                 * Skip the all-present length field. No overflow, we've just
                 * put a 16-bit value into a size_t.
                 */
                wct_ofs += 4;

                if (wct_ofs+2 > talloc_get_size(state->inbuf)) {
                        return NT_STATUS_INVALID_NETWORK_RESPONSE;
                }
        }

        status = smb1cli_pull_raw_error(state->inbuf);

        if (!smb1cli_have_andx_command(state->inbuf, wct_ofs, cmd)) {

                if ((cmd == SMBsesssetupX)
                    && NT_STATUS_EQUAL(
                            status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
                        /*
                         * NT_STATUS_MORE_PROCESSING_REQUIRED is a
                         * valid return code for session setup
                         */
                        goto no_err;
                }

                if (NT_STATUS_IS_ERR(status)) {
                        /*
                         * The last command takes the error code. All
                         * further commands down the requested chain
                         * will get a NT_STATUS_REQUEST_ABORTED.
                         */
                        return status;
                }
        } else {
                /*
                 * Only the last request in the chain get the returned
                 * status.
                 */
                status = NT_STATUS_OK;
        }

no_err:

        wct = CVAL(state->inbuf, wct_ofs);
        bytes_offset = wct_ofs + 1 + wct * sizeof(uint16_t);
        num_bytes = SVAL(state->inbuf, bytes_offset);

        if (wct < min_wct) {
                return NT_STATUS_INVALID_NETWORK_RESPONSE;
        }

        /*
         * wct_ofs is a 16-bit value plus 4, wct is a 8-bit value, num_bytes
         * is a 16-bit value. So bytes_offset being size_t should be far from
         * wrapping.
         */
        if ((bytes_offset + 2 > talloc_get_size(state->inbuf))
            || (bytes_offset > 0xffff)) {
                return NT_STATUS_INVALID_NETWORK_RESPONSE;
        }

        if (pwct != NULL) {
                *pwct = wct;
        }
        if (pvwv != NULL) {
                *pvwv = (uint16_t *)(state->inbuf + wct_ofs + 1);
        }
        if (pnum_bytes != NULL) {
                *pnum_bytes = num_bytes;
        }
        if (pbytes != NULL) {
                *pbytes = (uint8_t *)state->inbuf + bytes_offset + 2;
        }
        if ((mem_ctx != NULL) && (pinbuf != NULL)) {
                if (state->smb1.chain_num == state->smb1.chain_length-1) {
                        *pinbuf = talloc_move(mem_ctx, &state->inbuf);
                } else {
                        *pinbuf = state->inbuf;
                }
        }

        return status;
}

size_t smb1cli_req_wct_ofs(struct tevent_req **reqs, int num_reqs)
{
        size_t wct_ofs;
        int i;

        wct_ofs = HDR_WCT;

        for (i=0; i<num_reqs; i++) {
                struct smbXcli_req_state *state;
                state = tevent_req_data(reqs[i], struct smbXcli_req_state);
                wct_ofs += smbXcli_iov_len(state->smb1.iov+2,
                                           state->smb1.iov_count-2);
                wct_ofs = (wct_ofs + 3) & ~3;
        }
        return wct_ofs;
}

NTSTATUS smb1cli_req_chain_submit(struct tevent_req **reqs, int num_reqs)
{
        struct smbXcli_req_state *first_state =
                tevent_req_data(reqs[0],
                struct smbXcli_req_state);
        struct smbXcli_req_state *last_state =
                tevent_req_data(reqs[num_reqs-1],
                struct smbXcli_req_state);
        struct smbXcli_req_state *state;
        size_t wct_offset;
        size_t chain_padding = 0;
        int i, iovlen;
        struct iovec *iov = NULL;
        struct iovec *this_iov;
        NTSTATUS status;
        size_t nbt_len;

        if (num_reqs == 1) {
                return smb1cli_req_writev_submit(reqs[0], first_state,
                                                 first_state->smb1.iov,
                                                 first_state->smb1.iov_count);
        }

        iovlen = 0;
        for (i=0; i<num_reqs; i++) {
                if (!tevent_req_is_in_progress(reqs[i])) {
                        return NT_STATUS_INTERNAL_ERROR;
                }

                state = tevent_req_data(reqs[i], struct smbXcli_req_state);

                if (state->smb1.iov_count < 4) {
                        return NT_STATUS_INVALID_PARAMETER_MIX;
                }

                if (i == 0) {
                        /*
                         * The NBT and SMB header
                         */
                        iovlen += 2;
                } else {
                        /*
                         * Chain padding
                         */
                        iovlen += 1;
                }

                /*
                 * words and bytes
                 */
                iovlen += state->smb1.iov_count - 2;
        }

        iov = talloc_zero_array(last_state, struct iovec, iovlen);
        if (iov == NULL) {
                return NT_STATUS_NO_MEMORY;
        }

        first_state->smb1.chained_requests = (struct tevent_req **)talloc_memdup(
                last_state, reqs, sizeof(*reqs) * num_reqs);
        if (first_state->smb1.chained_requests == NULL) {
                TALLOC_FREE(iov);
                return NT_STATUS_NO_MEMORY;
        }

        wct_offset = HDR_WCT;
        this_iov = iov;

        for (i=0; i<num_reqs; i++) {
                size_t next_padding = 0;
                uint16_t *vwv;

                state = tevent_req_data(reqs[i], struct smbXcli_req_state);

                if (i < num_reqs-1) {
                        if (!smb1cli_is_andx_req(CVAL(state->smb1.hdr, HDR_COM))
                            || CVAL(state->smb1.hdr, HDR_WCT) < 2) {
                                TALLOC_FREE(iov);
                                TALLOC_FREE(first_state->smb1.chained_requests);
                                return NT_STATUS_INVALID_PARAMETER_MIX;
                        }
                }

                wct_offset += smbXcli_iov_len(state->smb1.iov+2,
                                              state->smb1.iov_count-2) + 1;
                if ((wct_offset % 4) != 0) {
                        next_padding = 4 - (wct_offset % 4);
                }
                wct_offset += next_padding;
                vwv = state->smb1.vwv;

                if (i < num_reqs-1) {
                        struct smbXcli_req_state *next_state =
                                tevent_req_data(reqs[i+1],
                                struct smbXcli_req_state);
                        SCVAL(vwv+0, 0, CVAL(next_state->smb1.hdr, HDR_COM));
                        SCVAL(vwv+0, 1, 0);
                        SSVAL(vwv+1, 0, wct_offset);
                } else if (smb1cli_is_andx_req(CVAL(state->smb1.hdr, HDR_COM))) {
                        /* properly end the chain */
                        SCVAL(vwv+0, 0, 0xff);
                        SCVAL(vwv+0, 1, 0xff);
                        SSVAL(vwv+1, 0, 0);
                }

                if (i == 0) {
                        /*
                         * The NBT and SMB header
                         */
                        this_iov[0] = state->smb1.iov[0];
                        this_iov[1] = state->smb1.iov[1];
                        this_iov += 2;
                } else {
                        /*
                         * This one is a bit subtle. We have to add
                         * chain_padding bytes between the requests, and we
                         * have to also include the wct field of the
                         * subsequent requests. We use the subsequent header
                         * for the padding, it contains the wct field in its
                         * last byte.
                         */
                        this_iov[0].iov_len = chain_padding+1;
                        this_iov[0].iov_base = (void *)&state->smb1.hdr[
                                sizeof(state->smb1.hdr) - this_iov[0].iov_len];
                        memset(this_iov[0].iov_base, 0, this_iov[0].iov_len-1);
                        this_iov += 1;
                }

                /*
                 * copy the words and bytes
                 */
                memcpy(this_iov, state->smb1.iov+2,
                       sizeof(struct iovec) * (state->smb1.iov_count-2));
                this_iov += state->smb1.iov_count - 2;
                chain_padding = next_padding;
        }

        nbt_len = smbXcli_iov_len(&iov[1], iovlen-1);
        if (nbt_len > first_state->conn->smb1.max_xmit) {
                TALLOC_FREE(iov);
                TALLOC_FREE(first_state->smb1.chained_requests);
                return NT_STATUS_INVALID_PARAMETER_MIX;
        }

        status = smb1cli_req_writev_submit(reqs[0], last_state, iov, iovlen);
        if (!NT_STATUS_IS_OK(status)) {
                TALLOC_FREE(iov);
                TALLOC_FREE(first_state->smb1.chained_requests);
                return status;
        }

        for (i=0; i < (num_reqs - 1); i++) {
                state = tevent_req_data(reqs[i], struct smbXcli_req_state);

                state->smb1.seqnum = last_state->smb1.seqnum;
        }

        return NT_STATUS_OK;
}

bool smbXcli_conn_has_async_calls(struct smbXcli_conn *conn)
{
        return ((tevent_queue_length(conn->outgoing) != 0)
                || (talloc_array_length(conn->pending) != 0));
}