/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.

 * Copyright (C) Bill Nagel <wnagel@tycoint.com>, Exacq Technologies

 *

 * This software is licensed as described in the file COPYING, which

 * you should have received as part of this distribution. The terms

 * are also available at https://curl.se/docs/copyright.html.

 *

 * You may opt to use, copy, modify, merge, publish, distribute and/or sell

 * copies of the Software, and permit persons to whom the Software is

 * furnished to do so, under the terms of the COPYING file.

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY

 * KIND, either express or implied.

 *

 * SPDX-License-Identifier: curl

 *

 ***************************************************************************/

#include "curl_setup.h"

#if !defined(CURL_DISABLE_SMB) && defined(USE_CURL_NTLM_CORE)

#include "smb.h"

#include "urldata.h"

#include "url.h"

#include "sendf.h"

#include "multiif.h"

#include "cfilters.h"

#include "connect.h"

#include "progress.h"

#include "transfer.h"

#include "select.h"

#include "vtls/vtls.h"

#include "curl_ntlm_core.h"

#include "escape.h"

#include "curl_endian.h"

/* The last 2 #include files should be in this order */

#include "curl_memory.h"

#include "memdebug.h"

/* meta key for storing protocol meta at easy handle */

#define CURL_META_SMB_EASY   "meta:proto:smb:easy"

/* meta key for storing protocol meta at connection */

#define CURL_META_SMB_CONN   "meta:proto:smb:conn"

enum smb_conn_state {

  SMB_NOT_CONNECTED = 0,

  SMB_CONNECTING,

  SMB_NEGOTIATE,

  SMB_SETUP,

  SMB_CONNECTED

};

/* SMB connection data, kept at connection */

struct smb_conn {

  enum smb_conn_state state;

  char *user;

  char *domain;

  char *share;

  unsigned char challenge[8];

  unsigned int session_key;

  unsigned short uid;

  char *recv_buf;

  char *send_buf;

  size_t upload_size;

  size_t send_size;

  size_t sent;

  size_t got;

};

/* SMB request state */

enum smb_req_state {

  SMB_REQUESTING,

  SMB_TREE_CONNECT,

  SMB_OPEN,

  SMB_DOWNLOAD,

  SMB_UPLOAD,

  SMB_CLOSE,

  SMB_TREE_DISCONNECT,

  SMB_DONE

};

/* SMB request data, kept at easy handle */

struct smb_request {

  enum smb_req_state state;

  char *path;

  unsigned short tid; /* Even if we connect to the same tree as another */

  unsigned short fid; /* request, the tid will be different */

  CURLcode result;

};

/*

 * Definitions for SMB protocol data structures

 */

#if defined(_MSC_VER) || defined(__ILEC400__)

#  define PACK

#  pragma pack(push)

#  pragma pack(1)

#elif defined(__GNUC__)

#  define PACK __attribute__((packed))

#else

#  define PACK

#endif

#define SMB_COM_CLOSE                 0x04

#define SMB_COM_READ_ANDX             0x2e

#define SMB_COM_WRITE_ANDX            0x2f

#define SMB_COM_TREE_DISCONNECT       0x71

#define SMB_COM_NEGOTIATE             0x72

#define SMB_COM_SETUP_ANDX            0x73

#define SMB_COM_TREE_CONNECT_ANDX     0x75

#define SMB_COM_NT_CREATE_ANDX        0xa2

#define SMB_COM_NO_ANDX_COMMAND       0xff

#define SMB_WC_CLOSE                  0x03

#define SMB_WC_READ_ANDX              0x0c

#define SMB_WC_WRITE_ANDX             0x0e

#define SMB_WC_SETUP_ANDX             0x0d

#define SMB_WC_TREE_CONNECT_ANDX      0x04

#define SMB_WC_NT_CREATE_ANDX         0x18

#define SMB_FLAGS_CANONICAL_PATHNAMES 0x10

#define SMB_FLAGS_CASELESS_PATHNAMES  0x08

/* #define SMB_FLAGS2_UNICODE_STRINGS    0x8000 */

#define SMB_FLAGS2_IS_LONG_NAME       0x0040

#define SMB_FLAGS2_KNOWS_LONG_NAME    0x0001

#define SMB_CAP_LARGE_FILES           0x08

#define SMB_GENERIC_WRITE             0x40000000

#define SMB_GENERIC_READ              0x80000000

#define SMB_FILE_SHARE_ALL            0x07

#define SMB_FILE_OPEN                 0x01

#define SMB_FILE_OVERWRITE_IF         0x05

#define SMB_ERR_NOACCESS              0x00050001

struct smb_header {

  unsigned char nbt_type;

  unsigned char nbt_flags;

  unsigned short nbt_length;

  unsigned char magic[4];

  unsigned char command;

  unsigned int status;

  unsigned char flags;

  unsigned short flags2;

  unsigned short pid_high;

  unsigned char signature[8];

  unsigned short pad;

  unsigned short tid;

  unsigned short pid;

  unsigned short uid;

  unsigned short mid;

} PACK;

struct smb_negotiate_response {

  struct smb_header h;

  unsigned char word_count;

  unsigned short dialect_index;

  unsigned char security_mode;

  unsigned short max_mpx_count;

  unsigned short max_number_vcs;

  unsigned int max_buffer_size;

  unsigned int max_raw_size;

  unsigned int session_key;

  unsigned int capabilities;

  unsigned int system_time_low;

  unsigned int system_time_high;

  unsigned short server_time_zone;

  unsigned char encryption_key_length;

  unsigned short byte_count;

  char bytes[1];

} PACK;

struct andx {

  unsigned char command;

  unsigned char pad;

  unsigned short offset;

} PACK;

struct smb_setup {

  unsigned char word_count;

  struct andx andx;

  unsigned short max_buffer_size;

  unsigned short max_mpx_count;

  unsigned short vc_number;

  unsigned int session_key;

  unsigned short lengths[2];

  unsigned int pad;

  unsigned int capabilities;

  unsigned short byte_count;

  char bytes[1024];

} PACK;

struct smb_tree_connect {

  unsigned char word_count;

  struct andx andx;

  unsigned short flags;

  unsigned short pw_len;

  unsigned short byte_count;

  char bytes[1024];

} PACK;

struct smb_nt_create {

  unsigned char word_count;

  struct andx andx;

  unsigned char pad;

  unsigned short name_length;

  unsigned int flags;

  unsigned int root_fid;

  unsigned int access;

  curl_off_t allocation_size;

  unsigned int ext_file_attributes;

  unsigned int share_access;

  unsigned int create_disposition;

  unsigned int create_options;

  unsigned int impersonation_level;

  unsigned char security_flags;

  unsigned short byte_count;

  char bytes[1024];

} PACK;

struct smb_nt_create_response {

  struct smb_header h;

  unsigned char word_count;

  struct andx andx;

  unsigned char op_lock_level;

  unsigned short fid;

  unsigned int create_disposition;

  curl_off_t create_time;

  curl_off_t last_access_time;

  curl_off_t last_write_time;

  curl_off_t last_change_time;

  unsigned int ext_file_attributes;

  curl_off_t allocation_size;

  curl_off_t end_of_file;

} PACK;

struct smb_read {

  unsigned char word_count;

  struct andx andx;

  unsigned short fid;

  unsigned int offset;

  unsigned short max_bytes;

  unsigned short min_bytes;

  unsigned int timeout;

  unsigned short remaining;

  unsigned int offset_high;

  unsigned short byte_count;

} PACK;

struct smb_write {

  struct smb_header h;

  unsigned char word_count;

  struct andx andx;

  unsigned short fid;

  unsigned int offset;

  unsigned int timeout;

  unsigned short write_mode;

  unsigned short remaining;

  unsigned short pad;

  unsigned short data_length;

  unsigned short data_offset;

  unsigned int offset_high;

  unsigned short byte_count;

  unsigned char pad2;

} PACK;

struct smb_close {

  unsigned char word_count;

  unsigned short fid;

  unsigned int last_mtime;

  unsigned short byte_count;

} PACK;

struct smb_tree_disconnect {

  unsigned char word_count;

  unsigned short byte_count;

} PACK;

#if defined(_MSC_VER) || defined(__ILEC400__)

#  pragma pack(pop)

#endif

/* Local API functions */

static CURLcode smb_setup_connection(struct Curl_easy *data,

                                     struct connectdata *conn);

static CURLcode smb_connect(struct Curl_easy *data, bool *done);

static CURLcode smb_connection_state(struct Curl_easy *data, bool *done);

static CURLcode smb_do(struct Curl_easy *data, bool *done);

static CURLcode smb_request_state(struct Curl_easy *data, bool *done);

static CURLcode smb_pollset(struct Curl_easy *data,

                            struct easy_pollset *ps);

static CURLcode smb_parse_url_path(struct Curl_easy *data,

                                   struct smb_conn *smbc,

                                   struct smb_request *req);

/*

 * SMB handler interface

 */

const struct Curl_handler Curl_handler_smb = {

  "smb",                                /* scheme */

  smb_setup_connection,                 /* setup_connection */

  smb_do,                               /* do_it */

  ZERO_NULL,                            /* done */

  ZERO_NULL,                            /* do_more */

  smb_connect,                          /* connect_it */

  smb_connection_state,                 /* connecting */

  smb_request_state,                    /* doing */

  smb_pollset,                          /* proto_pollset */

  smb_pollset,                          /* doing_pollset */

  ZERO_NULL,                            /* domore_pollset */

  ZERO_NULL,                            /* perform_pollset */

  ZERO_NULL,                            /* disconnect */

  ZERO_NULL,                            /* write_resp */

  ZERO_NULL,                            /* write_resp_hd */

  ZERO_NULL,                            /* connection_check */

  ZERO_NULL,                            /* attach connection */

  ZERO_NULL,                            /* follow */

  PORT_SMB,                             /* defport */

  CURLPROTO_SMB,                        /* protocol */

  CURLPROTO_SMB,                        /* family */

  PROTOPT_NONE                          /* flags */

};

#ifdef USE_SSL

/*

 * SMBS handler interface

 */

const struct Curl_handler Curl_handler_smbs = {

  "smbs",                               /* scheme */

  smb_setup_connection,                 /* setup_connection */

  smb_do,                               /* do_it */

  ZERO_NULL,                            /* done */

  ZERO_NULL,                            /* do_more */

  smb_connect,                          /* connect_it */

  smb_connection_state,                 /* connecting */

  smb_request_state,                    /* doing */

  smb_pollset,                          /* proto_pollset */

  smb_pollset,                          /* doing_pollset */

  ZERO_NULL,                            /* domore_pollset */

  ZERO_NULL,                            /* perform_pollset */

  ZERO_NULL,                            /* disconnect */

  ZERO_NULL,                            /* write_resp */

  ZERO_NULL,                            /* write_resp_hd */

  ZERO_NULL,                            /* connection_check */

  ZERO_NULL,                            /* attach connection */

  ZERO_NULL,                            /* follow */

  PORT_SMBS,                            /* defport */

  CURLPROTO_SMBS,                       /* protocol */

  CURLPROTO_SMB,                        /* family */

  PROTOPT_SSL                           /* flags */

};

#endif

#define MAX_PAYLOAD_SIZE  0x8000

#define MAX_MESSAGE_SIZE  (MAX_PAYLOAD_SIZE + 0x1000)

#define CLIENTNAME        "curl"

#define SERVICENAME       "?????"

/* SMB is mostly little endian */

#if (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) || \

  defined(__OS400__)

static unsigned short smb_swap16(unsigned short x)

{

  return (unsigned short) ((x << 8) | ((x >> 8) & 0xff));

}

static unsigned int smb_swap32(unsigned int x)

{

  return (x << 24) | ((x << 8) & 0xff0000) | ((x >> 8) & 0xff00) |

    ((x >> 24) & 0xff);

}

static curl_off_t smb_swap64(curl_off_t x)

{

  return ((curl_off_t) smb_swap32((unsigned int) x) << 32) |

    smb_swap32((unsigned int) (x >> 32));

}

#else

#  define smb_swap16(x) (x)

#  define smb_swap32(x) (x)

#  define smb_swap64(x) (x)

#endif

static void conn_state(struct Curl_easy *data, struct smb_conn *smbc,

                       enum smb_conn_state newstate)

{

#if defined(DEBUGBUILD) && !defined(CURL_DISABLE_VERBOSE_STRINGS)

  /* For debug purposes */

  static const char * const names[] = {

    "SMB_NOT_CONNECTED",

    "SMB_CONNECTING",

    "SMB_NEGOTIATE",

    "SMB_SETUP",

    "SMB_CONNECTED",

    /* LAST */

  };

  if(smbc->state != newstate)

    infof(data, "SMB conn %p state change from %s to %s",

          (void *)smbc, names[smbc->state], names[newstate]);

#endif

  (void)data;

  smbc->state = newstate;

}

static void request_state(struct Curl_easy *data,

                          enum smb_req_state newstate)

{

  struct smb_request *req = Curl_meta_get(data, CURL_META_SMB_EASY);

  if(req) {

#if defined(DEBUGBUILD) && !defined(CURL_DISABLE_VERBOSE_STRINGS)

    /* For debug purposes */

    static const char * const names[] = {

      "SMB_REQUESTING",

      "SMB_TREE_CONNECT",

      "SMB_OPEN",

      "SMB_DOWNLOAD",

      "SMB_UPLOAD",

      "SMB_CLOSE",

      "SMB_TREE_DISCONNECT",

      "SMB_DONE",

      /* LAST */

    };

    if(req->state != newstate)

      infof(data, "SMB request %p state change from %s to %s",

            (void *)req, names[req->state], names[newstate]);

#endif

    req->state = newstate;

  }

}

static void smb_easy_dtor(void *key, size_t klen, void *entry)

{

  struct smb_request *req = entry;

  (void)key;

  (void)klen;

  /* `req->path` points to somewhere in `struct smb_conn` which is

   * kept at the connection meta. If the connection is destroyed first,

   * req->path points to free'd memory. */

  free(req);

}

static void smb_conn_dtor(void *key, size_t klen, void *entry)

{

  struct smb_conn *smbc = entry;

  (void)key;

  (void)klen;

  Curl_safefree(smbc->share);

  Curl_safefree(smbc->domain);

  Curl_safefree(smbc->recv_buf);

  Curl_safefree(smbc->send_buf);

  free(smbc);

}

/* this should setup things in the connection, not in the easy

   handle */

static CURLcode smb_setup_connection(struct Curl_easy *data,

                                     struct connectdata *conn)

{

  struct smb_conn *smbc;

  struct smb_request *req;

  /* Initialize the connection state */

  smbc = calloc(1, sizeof(*smbc));

  if(!smbc ||

     Curl_conn_meta_set(conn, CURL_META_SMB_CONN, smbc, smb_conn_dtor))

    return CURLE_OUT_OF_MEMORY;

  /* Initialize the request state */

  req = calloc(1, sizeof(*req));

  if(!req ||

     Curl_meta_set(data, CURL_META_SMB_EASY, req, smb_easy_dtor))

    return CURLE_OUT_OF_MEMORY;

  /* Parse the URL path */

  return smb_parse_url_path(data, smbc, req);

}

static CURLcode smb_connect(struct Curl_easy *data, bool *done)

{

  struct connectdata *conn = data->conn;

  struct smb_conn *smbc = Curl_conn_meta_get(conn, CURL_META_SMB_CONN);

  char *slash;

  (void)done;

  if(!smbc)

    return CURLE_FAILED_INIT;

  /* Check we have a username and password to authenticate with */

  if(!data->state.aptr.user)

    return CURLE_LOGIN_DENIED;

  /* Initialize the connection state */

  smbc->state = SMB_CONNECTING;

  smbc->recv_buf = malloc(MAX_MESSAGE_SIZE);

  if(!smbc->recv_buf)

    return CURLE_OUT_OF_MEMORY;

  smbc->send_buf = malloc(MAX_MESSAGE_SIZE);

  if(!smbc->send_buf)

    return CURLE_OUT_OF_MEMORY;

  /* Multiple requests are allowed with this connection */

  connkeep(conn, "SMB default");

  /* Parse the username, domain, and password */

  slash = strchr(conn->user, '/');

  if(!slash)

    slash = strchr(conn->user, '\\');

  if(slash) {

    smbc->user = slash + 1;

    smbc->domain = strdup(conn->user);

    if(!smbc->domain)

      return CURLE_OUT_OF_MEMORY;

    smbc->domain[slash - conn->user] = 0;

  }

  else {

    smbc->user = conn->user;

    smbc->domain = strdup(conn->host.name);

    if(!smbc->domain)

      return CURLE_OUT_OF_MEMORY;

  }

  return CURLE_OK;

}

static CURLcode smb_recv_message(struct Curl_easy *data,

                                 struct smb_conn *smbc,

                                 void **msg)

{

  char *buf = smbc->recv_buf;

  size_t bytes_read;

  size_t nbt_size;

  size_t msg_size = sizeof(struct smb_header);

  size_t len = MAX_MESSAGE_SIZE - smbc->got;

  CURLcode result;

  result = Curl_xfer_recv(data, buf + smbc->got, len, &bytes_read);

  if(result)

    return result;

  if(!bytes_read)

    return CURLE_OK;

  smbc->got += bytes_read;

  /* Check for a 32-bit nbt header */

  if(smbc->got < sizeof(unsigned int))

    return CURLE_OK;

  nbt_size = Curl_read16_be((const unsigned char *)

                            (buf + sizeof(unsigned short))) +

    sizeof(unsigned int);

  if(nbt_size > MAX_MESSAGE_SIZE) {

    failf(data, "too large NetBIOS frame size %zu", nbt_size);

    return CURLE_RECV_ERROR;

  }

  else if(nbt_size < msg_size) {

    /* Each SMB message must be at least this large, e.g. 32 bytes */

    failf(data, "too small NetBIOS frame size %zu", nbt_size);

    return CURLE_RECV_ERROR;

  }

  if(smbc->got < nbt_size)

    return CURLE_OK;

  if(nbt_size >= msg_size + 1) {

    /* Add the word count */

    msg_size += 1 + ((unsigned char) buf[msg_size]) * sizeof(unsigned short);

    if(nbt_size >= msg_size + sizeof(unsigned short)) {

      /* Add the byte count */

      msg_size += sizeof(unsigned short) +

        Curl_read16_le((const unsigned char *)&buf[msg_size]);

      if(nbt_size < msg_size)

        return CURLE_RECV_ERROR;

    }

  }

  *msg = buf;

  return CURLE_OK;

}

static void smb_pop_message(struct smb_conn *smbc)

{

  smbc->got = 0;

}

static void smb_format_message(struct smb_conn *smbc,

                               struct smb_request *req,

                               struct smb_header *h,

                               unsigned char cmd, size_t len)

{

  const unsigned int pid = 0xbad71d; /* made up */

  memset(h, 0, sizeof(*h));

  h->nbt_length = htons((unsigned short) (sizeof(*h) - sizeof(unsigned int) +

                                          len));

  memcpy((char *)h->magic, "\xffSMB", 4);

  h->command = cmd;

  h->flags = SMB_FLAGS_CANONICAL_PATHNAMES | SMB_FLAGS_CASELESS_PATHNAMES;

  h->flags2 = smb_swap16(SMB_FLAGS2_IS_LONG_NAME | SMB_FLAGS2_KNOWS_LONG_NAME);

  h->uid = smb_swap16(smbc->uid);

  h->tid = smb_swap16(req->tid);

  h->pid_high = smb_swap16((unsigned short)(pid >> 16));

  h->pid = smb_swap16((unsigned short) pid);

}

static CURLcode smb_send(struct Curl_easy *data, struct smb_conn *smbc,

                         size_t len, size_t upload_size)

{

  size_t bytes_written;

  CURLcode result;

  result = Curl_xfer_send(data, smbc->send_buf, len, FALSE, &bytes_written);

  if(result)

    return result;

  if(bytes_written != len) {

    smbc->send_size = len;

    smbc->sent = bytes_written;

  }

  smbc->upload_size = upload_size;

  return CURLE_OK;

}

static CURLcode smb_flush(struct Curl_easy *data, struct smb_conn *smbc)

{

  size_t bytes_written;

  size_t len = smbc->send_size - smbc->sent;

  CURLcode result;

  if(!smbc->send_size)

    return CURLE_OK;

  result = Curl_xfer_send(data, smbc->send_buf + smbc->sent, len, FALSE,

                          &bytes_written);

  if(result)

    return result;

  if(bytes_written != len)

    smbc->sent += bytes_written;

  else

    smbc->send_size = 0;

  return CURLE_OK;

}

static CURLcode smb_send_message(struct Curl_easy *data,

                                 struct smb_conn *smbc,

                                 struct smb_request *req,

                                 unsigned char cmd,

                                 const void *msg, size_t msg_len)

{

  smb_format_message(smbc, req, (struct smb_header *)smbc->send_buf,

                     cmd, msg_len);

  if((sizeof(struct smb_header) + msg_len) > MAX_MESSAGE_SIZE) {

    DEBUGASSERT(0);

    return CURLE_SEND_ERROR;

  }

  memcpy(smbc->send_buf + sizeof(struct smb_header), msg, msg_len);

  return smb_send(data, smbc, sizeof(struct smb_header) + msg_len, 0);

}

static CURLcode smb_send_negotiate(struct Curl_easy *data,

                                   struct smb_conn *smbc,

                                   struct smb_request *req)

{

  const char *msg = "\x00\x0c\x00\x02NT LM 0.12";

  return smb_send_message(data, smbc, req, SMB_COM_NEGOTIATE, msg, 15);

}

static CURLcode smb_send_setup(struct Curl_easy *data)

{

  struct connectdata *conn = data->conn;

  struct smb_conn *smbc = Curl_conn_meta_get(conn, CURL_META_SMB_CONN);

  struct smb_request *req = Curl_meta_get(data, CURL_META_SMB_EASY);

  struct smb_setup msg;

  char *p = msg.bytes;

  unsigned char lm_hash[21];

  unsigned char lm[24];

  unsigned char nt_hash[21];

  unsigned char nt[24];

  size_t byte_count;

  if(!smbc || !req)

    return CURLE_FAILED_INIT;

  byte_count = sizeof(lm) + sizeof(nt) +

    strlen(smbc->user) + strlen(smbc->domain) +

    strlen(CURL_OS) + strlen(CLIENTNAME) + 4; /* 4 null chars */

  if(byte_count > sizeof(msg.bytes))

    return CURLE_FILESIZE_EXCEEDED;

  Curl_ntlm_core_mk_lm_hash(conn->passwd, lm_hash);

  Curl_ntlm_core_lm_resp(lm_hash, smbc->challenge, lm);

  Curl_ntlm_core_mk_nt_hash(conn->passwd, nt_hash);

  Curl_ntlm_core_lm_resp(nt_hash, smbc->challenge, nt);

  memset(&msg, 0, sizeof(msg) - sizeof(msg.bytes));

  msg.word_count = SMB_WC_SETUP_ANDX;

  msg.andx.command = SMB_COM_NO_ANDX_COMMAND;

  msg.max_buffer_size = smb_swap16(MAX_MESSAGE_SIZE);

  msg.max_mpx_count = smb_swap16(1);

  msg.vc_number = smb_swap16(1);

  msg.session_key = smb_swap32(smbc->session_key);

  msg.capabilities = smb_swap32(SMB_CAP_LARGE_FILES);

  msg.lengths[0] = smb_swap16(sizeof(lm));

  msg.lengths[1] = smb_swap16(sizeof(nt));

  memcpy(p, lm, sizeof(lm));

  p += sizeof(lm);

  memcpy(p, nt, sizeof(nt));

  p += sizeof(nt);

  p += curl_msnprintf(p, byte_count - sizeof(nt) - sizeof(lm),

                      "%s%c"  /* user */

                      "%s%c"  /* domain */

                      "%s%c"  /* OS */

                      "%s", /* client name */

                      smbc->user, 0, smbc->domain, 0, CURL_OS, 0, CLIENTNAME);

  p++; /* count the final null-termination */

  DEBUGASSERT(byte_count == (size_t)(p - msg.bytes));

  msg.byte_count = smb_swap16((unsigned short)byte_count);

  return smb_send_message(data, smbc, req, SMB_COM_SETUP_ANDX, &msg,

                          sizeof(msg) - sizeof(msg.bytes) + byte_count);

}

static CURLcode smb_send_tree_connect(struct Curl_easy *data,

                                      struct smb_conn *smbc,

                                      struct smb_request *req)

{

  struct smb_tree_connect msg;

  struct connectdata *conn = data->conn;

  char *p = msg.bytes;

  const size_t byte_count = strlen(conn->host.name) + strlen(smbc->share) +

    strlen(SERVICENAME) + 5; /* 2 nulls and 3 backslashes */

  if(byte_count > sizeof(msg.bytes))

    return CURLE_FILESIZE_EXCEEDED;

  memset(&msg, 0, sizeof(msg) - sizeof(msg.bytes));

  msg.word_count = SMB_WC_TREE_CONNECT_ANDX;

  msg.andx.command = SMB_COM_NO_ANDX_COMMAND;

  msg.pw_len = 0;

  p += curl_msnprintf(p, byte_count,

                      "\\\\%s\\"  /* hostname */

                      "%s%c"      /* share */

                      "%s",       /* service */

                      conn->host.name, smbc->share, 0, SERVICENAME);

  p++; /* count the final null-termination */

  DEBUGASSERT(byte_count == (size_t)(p - msg.bytes));

  msg.byte_count = smb_swap16((unsigned short)byte_count);

  return smb_send_message(data, smbc, req, SMB_COM_TREE_CONNECT_ANDX, &msg,

                          sizeof(msg) - sizeof(msg.bytes) + byte_count);

}

static CURLcode smb_send_open(struct Curl_easy *data,

                              struct smb_conn *smbc,

                              struct smb_request *req)

{

  struct smb_nt_create msg;

  const size_t byte_count = strlen(req->path) + 1;

  if(byte_count > sizeof(msg.bytes))

    return CURLE_FILESIZE_EXCEEDED;

  memset(&msg, 0, sizeof(msg) - sizeof(msg.bytes));

  msg.word_count = SMB_WC_NT_CREATE_ANDX;

  msg.andx.command = SMB_COM_NO_ANDX_COMMAND;

  msg.name_length = smb_swap16((unsigned short)(byte_count - 1));

  msg.share_access = smb_swap32(SMB_FILE_SHARE_ALL);

  if(data->state.upload) {

    msg.access = smb_swap32(SMB_GENERIC_READ | SMB_GENERIC_WRITE);

    msg.create_disposition = smb_swap32(SMB_FILE_OVERWRITE_IF);

  }

  else {

    msg.access = smb_swap32(SMB_GENERIC_READ);

    msg.create_disposition = smb_swap32(SMB_FILE_OPEN);

  }

  msg.byte_count = smb_swap16((unsigned short) byte_count);

  strcpy(msg.bytes, req->path);

  return smb_send_message(data, smbc, req, SMB_COM_NT_CREATE_ANDX, &msg,

                          sizeof(msg) - sizeof(msg.bytes) + byte_count);

}

static CURLcode smb_send_close(struct Curl_easy *data,

                               struct smb_conn *smbc,

                               struct smb_request *req)

{

  struct smb_close msg;

  memset(&msg, 0, sizeof(msg));

  msg.word_count = SMB_WC_CLOSE;

  msg.fid = smb_swap16(req->fid);

  return smb_send_message(data, smbc, req, SMB_COM_CLOSE, &msg, sizeof(msg));

}

static CURLcode smb_send_tree_disconnect(struct Curl_easy *data,

                                         struct smb_conn *smbc,

                                         struct smb_request *req)

{

  struct smb_tree_disconnect msg;

  memset(&msg, 0, sizeof(msg));

  return smb_send_message(data, smbc, req, SMB_COM_TREE_DISCONNECT,

                          &msg, sizeof(msg));

}

static CURLcode smb_send_read(struct Curl_easy *data,

                              struct smb_conn *smbc,

                              struct smb_request *req)

{

  curl_off_t offset = data->req.offset;

  struct smb_read msg;

  memset(&msg, 0, sizeof(msg));

  msg.word_count = SMB_WC_READ_ANDX;

  msg.andx.command = SMB_COM_NO_ANDX_COMMAND;

  msg.fid = smb_swap16(req->fid);

  msg.offset = smb_swap32((unsigned int) offset);

  msg.offset_high = smb_swap32((unsigned int) (offset >> 32));

  msg.min_bytes = smb_swap16(MAX_PAYLOAD_SIZE);

  msg.max_bytes = smb_swap16(MAX_PAYLOAD_SIZE);

  return smb_send_message(data, smbc, req, SMB_COM_READ_ANDX,

                          &msg, sizeof(msg));

}

static CURLcode smb_send_write(struct Curl_easy *data,

                               struct smb_conn *smbc,

                               struct smb_request *req)

{

  struct smb_write *msg;

  curl_off_t offset = data->req.offset;

  curl_off_t upload_size = data->req.size - data->req.bytecount;

  msg = (struct smb_write *)smbc->send_buf;

  if(upload_size >= MAX_PAYLOAD_SIZE - 1) /* There is one byte of padding */

    upload_size = MAX_PAYLOAD_SIZE - 1;

  memset(msg, 0, sizeof(*msg));

  msg->word_count = SMB_WC_WRITE_ANDX;

  msg->andx.command = SMB_COM_NO_ANDX_COMMAND;

  msg->fid = smb_swap16(req->fid);

  msg->offset = smb_swap32((unsigned int) offset);

  msg->offset_high = smb_swap32((unsigned int) (offset >> 32));

  msg->data_length = smb_swap16((unsigned short) upload_size);

  msg->data_offset = smb_swap16(sizeof(*msg) - sizeof(unsigned int));

  msg->byte_count = smb_swap16((unsigned short) (upload_size + 1));

  smb_format_message(smbc, req, &msg->h, SMB_COM_WRITE_ANDX,

                     sizeof(*msg) - sizeof(msg->h) + (size_t) upload_size);

  return smb_send(data, smbc, sizeof(*msg), (size_t) upload_size);

}

static CURLcode smb_send_and_recv(struct Curl_easy *data,

                                  struct smb_conn *smbc, void **msg)

{

  CURLcode result;

  *msg = NULL; /* if it returns early */

  /* Check if there is data in the transfer buffer */

  if(!smbc->send_size && smbc->upload_size) {

    size_t nread = smbc->upload_size > (size_t)MAX_MESSAGE_SIZE ?

      (size_t)MAX_MESSAGE_SIZE : smbc->upload_size;

    bool eos;

    result = Curl_client_read(data, smbc->send_buf, nread, &nread, &eos);

    if(result && result != CURLE_AGAIN)

      return result;

    if(!nread)

      return CURLE_OK;

    smbc->upload_size -= nread;

    smbc->send_size = nread;

    smbc->sent = 0;

  }

  /* Check if there is data to send */

  if(smbc->send_size) {

    result = smb_flush(data, smbc);

    if(result)

      return result;

  }

  /* Check if there is still data to be sent */

  if(smbc->send_size || smbc->upload_size)

    return CURLE_AGAIN;

  return smb_recv_message(data, smbc, msg);

}

static CURLcode smb_connection_state(struct Curl_easy *data, bool *done)

{

  struct connectdata *conn = data->conn;

  struct smb_conn *smbc = Curl_conn_meta_get(conn, CURL_META_SMB_CONN);

  struct smb_request *req = Curl_meta_get(data, CURL_META_SMB_EASY);

  struct smb_negotiate_response *nrsp;

  struct smb_header *h;

  CURLcode result;

  void *msg = NULL;

  if(!smbc || !req)

    return CURLE_FAILED_INIT;

  if(smbc->state == SMB_CONNECTING) {

#ifdef USE_SSL

    if(Curl_conn_is_ssl(conn, FIRSTSOCKET)) {

      bool ssl_done = FALSE;

      result = Curl_conn_connect(data, FIRSTSOCKET, FALSE, &ssl_done);

      if(result && result != CURLE_AGAIN)

        return result;

      if(!ssl_done)

        return CURLE_OK;

    }

#endif

    result = smb_send_negotiate(data, smbc, req);

    if(result) {

      connclose(conn, "SMB: failed to send negotiate message");

      return result;

    }

    conn_state(data, smbc, SMB_NEGOTIATE);

  }

  /* Send the previous message and check for a response */

  result = smb_send_and_recv(data, smbc, &msg);

  if(result && result != CURLE_AGAIN) {

    connclose(conn, "SMB: failed to communicate");

    return result;

  }

  if(!msg)

    return CURLE_OK;

  h = msg;

  switch(smbc->state) {