/*
Header file to send and recieve SPIN/SPOUT commands to SCSI device

Original program copyright 2010 John D. Coleman

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; version 2 of the License.

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.
*/
#include <bitset>
#include <config.h>
#include <errno.h>
#include <fcntl.h>
#include <iomanip>
#include <iostream>
#include <sstream>
#include <string>
#include <sys/ioctl.h>

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif

#if defined(OS_LINUX)
#include <scsi/scsi.h>
#include <scsi/sg.h>
#define SCSI_TIMEOUT 5000
#elif defined(OS_FREEBSD)
#include <cam/scsi/scsi_sg.h>
#define SCSI_TIMEOUT 5000
#elif defined(OS_AIX)
#define _LINUX_SOURCE_COMPAT
#include <sys/Atape.h>
#include <sys/scsi.h>
#include <sys/scsi_buf.h>
#include <sys/tape.h>
#define SCSI_TIMEOUT 5
#else
#error "OS type is not set"
#endif

#include "scsiencrypt.h"
#include <sys/mtio.h>

#define SSP_SPIN_OPCODE 0XA2
#define SSP_SPOUT_OPCODE 0XB5
#define SSP_SP_CMD_LEN 12
#define SSP_SP_PROTOCOL_TDE 0X20

#define RETRYCOUNT 1

#define BSINTTOCHAR(x)                                                         \
  (unsigned char)((x & 0xff000000) >> 24),                                     \
      (unsigned char)((x & 0x00ff0000) >> 16),                                 \
      (unsigned char)((x & 0x0000ff00) >> 8), (unsigned char)(x & 0x000000ff)

void byteswap(unsigned char *array, int size, int value);
bool moveTape(std::string tapeDevice, int count, bool dirForward);
void outputSense(SCSI_PAGE_SENSE *sd);
void readIOError(int err);

bool SCSIExecute(std::string tapedevice, unsigned char *cmd_p, int cmd_len,
                 unsigned char *dxfer_p, int dxfer_len, bool cmd_to_device,
                 bool show_error);

typedef struct { // structure for setting data encryption
  unsigned char pageCode[2];
  unsigned char length[2];

#if STENC_BIG_ENDIAN == 1
  unsigned char scope : 3;
  unsigned char res_bits_1 : 4;
  unsigned char lock : 1;
#else
  unsigned char lock : 1;
  unsigned char res_bits_1 : 4;
  unsigned char scope : 3;
#endif

#if STENC_BIG_ENDIAN == 1
  unsigned char CEEM : 2;
  unsigned char RDMC : 2;
  unsigned char sdk : 1;
  unsigned char ckod : 1;
  unsigned char ckorp : 1;
  unsigned char ckorl : 1;
#else
  unsigned char ckorl : 1;
  unsigned char ckorp : 1;
  unsigned char ckod : 1;
  unsigned char sdk : 1;
  unsigned char RDMC : 2;
  unsigned char CEEM : 2;
#endif
  unsigned char encryptionMode;
  unsigned char decryptionMode;
  unsigned char algorithmIndex;
  unsigned char keyFormat;
  unsigned char res_bits_2[8];
  unsigned char keyLength[2];
  unsigned char keyData[SSP_KEY_LENGTH];
} SSP_PAGE_SDE;

unsigned char scsi_sense_command[6] = {0x03, 0, 0, 0, sizeof(SCSI_PAGE_SENSE),
                                       0},
              scsi_inq_command[6] = {0x12, 0, 0, 0, sizeof(SCSI_PAGE_INQ), 0},
              spin_des_command[SSP_SP_CMD_LEN] = {SSP_SPIN_OPCODE,
                                                  SSP_SP_PROTOCOL_TDE,
                                                  0,
                                                  0X20,
                                                  0,
                                                  0,
                                                  BSINTTOCHAR(
                                                      sizeof(SSP_PAGE_BUFFER)),
                                                  0,
                                                  0},
              spin_nbes_command[SSP_SP_CMD_LEN] = {
                  SSP_SPIN_OPCODE,
                  SSP_SP_PROTOCOL_TDE,
                  0,
                  0X21,
                  0,
                  0,
                  BSINTTOCHAR(sizeof(SSP_PAGE_BUFFER)),
                  0,
                  0};

// Gets encryption options on the tape drive
SSP_DES *SSPGetDES(std::string tapeDevice) {
  SSP_PAGE_BUFFER buffer;
  memset(&buffer, 0, sizeof(SSP_PAGE_BUFFER));
  if (!SCSIExecute(tapeDevice, (unsigned char *)&spin_des_command,
                   sizeof(spin_des_command), (unsigned char *)&buffer,
                   sizeof(SSP_PAGE_BUFFER), false, true)) {
    return NULL;
  }
  SSP_DES *status = new SSP_DES(&buffer);
  return status;
}

// Gets encryption options on the tape drive
SSP_NBES *SSPGetNBES(std::string tapeDevice, bool retry) {

  SSP_PAGE_BUFFER buffer;
  memset(&buffer, 0, sizeof(SSP_PAGE_BUFFER));
  if (!SCSIExecute(tapeDevice, (unsigned char *)&spin_nbes_command,
                   sizeof(spin_nbes_command), (unsigned char *)&buffer,
                   sizeof(SSP_PAGE_BUFFER), false, false)) {
    return NULL;
  }
  SSP_NBES *status = new SSP_NBES(&buffer);
  if (status->nbes.encryptionStatus == 0x01 && retry) {
    // move to the start of the tape and try again
    int moves = 0;
    while (true) {
      if (status == NULL)
        break;
      if (status->nbes.encryptionStatus != 0x01)
        break;
      if (moves >= MAX_TAPE_READ_BLOCKS)
        break;
      delete status;
      status = NULL; // double free bug fix provided by Adam Nielsen
      if (!moveTape(tapeDevice, 1, true))
        break;
      moves++;
      status = SSPGetNBES(tapeDevice, false);
    }
    moveTape(tapeDevice, moves, false);
  }
  return status;
}

// Sends and inquiry to the device
SCSI_PAGE_INQ *SCSIGetInquiry(std::string tapeDevice) {
  SCSI_PAGE_INQ *status = new SCSI_PAGE_INQ;
  memset(status, 0, sizeof(SCSI_PAGE_INQ));
  if (!SCSIExecute(tapeDevice, (unsigned char *)&scsi_inq_command,
                   sizeof(scsi_inq_command), (unsigned char *)status,
                   sizeof(SCSI_PAGE_INQ), false, true)) {
    exit(EXIT_FAILURE);
  }
  return status;
}

int SCSIInitSDEPage(SCSIEncryptOptions *eOptions,
                    uint8_t *buffer) {
  SSP_PAGE_SDE options;
  // copy the template over the options
  memset(&options, 0, sizeof(SSP_PAGE_SDE));
  byteswap((unsigned char *)&options.pageCode, 2, 0x10);
  int pagelen = sizeof(SSP_PAGE_SDE);
  options.scope = 2; // all IT nexus = 10b
  options.RDMC = eOptions->rdmc;
  options.ckod = (eOptions->CKOD) ? 1 : 0;
  options.CEEM = DEFAULT_CEEM;
  options.algorithmIndex = eOptions->algorithmIndex;
  // set the specific options
  switch (eOptions->cryptMode) {
    case CRYPTMODE_ON: // encrypt, read only encrypted data
      options.encryptionMode = 2;
      options.decryptionMode = 2;
      break;
    case CRYPTMODE_MIXED: // encrypt, read all data
      options.encryptionMode = 2;
      options.decryptionMode = 3;
      break;
    case CRYPTMODE_RAWREAD:
      options.encryptionMode = 2;
      options.decryptionMode = 1;
      break;
    default:
      byteswap((unsigned char *)options.keyLength, 2, DEFAULT_KEYSIZE);
      eOptions->cryptoKey.clear(); // blank the key
      eOptions->keyName.clear(); // blank the key name, not supported when turned off
      break;
  }

  if (!eOptions->cryptoKey.empty()) {
    // byte swap the keylength
    byteswap((unsigned char *)&options.keyLength, 2,
             eOptions->cryptoKey.size());
    // copy the crypto key into the options
    std::copy(eOptions->cryptoKey.begin(), eOptions->cryptoKey.end(), options.keyData);
  }
  // create the key descriptor
  if (!eOptions->keyName.empty()) {
    SSP_KAD kad;
    memset(&kad, 0, sizeof(kad));
    // set the descriptor length to the length of the keyName
    byteswap((unsigned char *)&kad.descriptorLength, 2,
             eOptions->keyName.size());

    // get the size of the kad object
    int kadlen = eOptions->keyName.size() + SSP_KAD_HEAD_LENGTH;
    // increment the SPOUT page len
    pagelen += kadlen;
    // increase the page size
    eOptions->keyName.copy((char *)&kad.descriptor, eOptions->keyName.size(),
                           0);
    // copy the kad after the SDE command
    memcpy(&buffer[sizeof(SSP_PAGE_SDE)], &kad, kadlen);
  }
  // update the pagelen in options
  byteswap((unsigned char *)&options.length, 2,
           pagelen - 4); // set the page length, minus the length and pageCode

  // copy the options to the beginning of the buffer
  memcpy(buffer, &options, sizeof(SSP_PAGE_SDE));
  return pagelen;
}

// Writes encryption options to the tape drive
bool SCSIWriteEncryptOptions(std::string tapeDevice,
                             SCSIEncryptOptions *eOptions) {
  uint8_t buffer[1024];
  memset(&buffer, 0, 1024);
  int pagelen = SCSIInitSDEPage(eOptions, buffer);

  unsigned char spout_sde_command[SSP_SP_CMD_LEN] = {SSP_SPOUT_OPCODE,
                                                     SSP_SP_PROTOCOL_TDE,
                                                     0,
                                                     0X10,
                                                     0,
                                                     0,
                                                     BSINTTOCHAR(pagelen),
                                                     0,
                                                     0};

  // return whether or not the command executed
  return SCSIExecute(tapeDevice, (unsigned char *)&spout_sde_command,
                     sizeof(spout_sde_command), (unsigned char *)&buffer,
                     pagelen, true, true);
}

bool SCSIExecute(std::string tapedrive, unsigned char *cmd_p, int cmd_len,
                 unsigned char *dxfer_p, int dxfer_len, bool cmd_to_device,
                 bool show_error) {
  const char *tapedevice = tapedrive.c_str();
  int sg_fd, eresult, sresult, ioerr, retries;
  SCSI_PAGE_SENSE *sd = new SCSI_PAGE_SENSE;
  memset(sd, 0, sizeof(SCSI_PAGE_SENSE));

#if defined(OS_LINUX) || defined(OS_FREEBSD) // Linux or FreeBSD System
  errno = 0;
  sg_fd = open(tapedevice, O_RDONLY);
  if (sg_fd == -1) {
    std::cerr << "Could not open device '" << tapedevice << "': ";
    readIOError(errno);
    exit(EXIT_FAILURE);
  }

  sg_io_hdr cmdio;
  memset(&cmdio, 0, sizeof(sg_io_hdr));
  cmdio.cmd_len = cmd_len;
  cmdio.dxfer_direction = (cmd_to_device) ? SG_DXFER_TO_DEV : SG_DXFER_FROM_DEV;
  cmdio.dxfer_len = dxfer_len;
  cmdio.dxferp = dxfer_p;
  cmdio.cmdp = cmd_p;
  cmdio.sbp = (unsigned char *)sd;
  cmdio.mx_sb_len = sizeof(SCSI_PAGE_SENSE);
  cmdio.timeout = SCSI_TIMEOUT;
  cmdio.interface_id = 'S';
  retries = 0;
  do {
    errno = 0;
    eresult = ioctl(sg_fd, SG_IO, &cmdio);
    if (eresult != 0)
      ioerr = errno;
    retries++;
  } while (errno != 0 && retries <= RETRYCOUNT);

  sresult = cmdio.status;
#elif defined(OS_AIX) // AIX System

  errno = 0;
  sg_fd = openx((char *)tapedevice, O_RDONLY, NULL, SC_DIAGNOSTIC);
  if (!sg_fd || sg_fd == -1) {
    std::cerr << "Could not open device '" << tapedevice << "'" << std::endl;
    exit(EXIT_FAILURE);
  }

  struct sc_iocmd cmdio;
  memset(&cmdio, 0, sizeof(struct sc_iocmd));
  // copy the command bytes into the first part of the structure
  memcpy(&cmdio.scsi_cdb, cmd_p, cmd_len);
  cmdio.buffer = (char *)dxfer_p;
  cmdio.timeout_value = SCSI_TIMEOUT;
  cmdio.command_length = cmd_len;
  cmdio.data_length = dxfer_len;
  cmdio.status_validity = SC_SCSI_ERROR;
  cmdio.flags = (cmd_to_device) ? B_WRITE : B_READ;

  retries = 0;
  do {
    errno = 0;
    eresult = ioctl(sg_fd, STIOCMD, &cmdio);
    sresult = (int)cmdio.scsi_bus_status;
    if (eresult != 0)
      ioerr = errno;
    retries++;
  } while (errno != 0 && retries <= RETRYCOUNT);

  if (sresult == SC_CHECK_CONDITION) { // get the sense data

    struct sc_iocmd scmdio;
    memset(&scmdio, 0, sizeof(struct sc_iocmd));
    // copy the command bytes into the first part of the structure
    memcpy(&scmdio.scsi_cdb, &scsi_sense_command, sizeof(scsi_sense_command));
    scmdio.buffer = (char *)sd;
    scmdio.timeout_value = SCSI_TIMEOUT;
    scmdio.command_length = sizeof(scsi_sense_command);
    scmdio.data_length = sizeof(SCSI_PAGE_SENSE);
    scmdio.status_validity = SC_SCSI_ERROR;
    scmdio.flags = B_READ;

    errno = 0;
    ioctl(sg_fd, STIOCMD, &scmdio);
  }
#else
#error "OS type is not set"
#endif
#ifdef DEBUGSCSI
  std::cout << "SCSI Command: ";
  for (int i = 0; i < cmd_len; i++) {
    std::cout << HEX(cmd_p[i]);
  }
  std::cout << "\n";

  std::cout << "SCSI Data: ";
  for (int i = 0; i < dxfer_len; i++) {
    std::cout << HEX(dxfer_p[i]);
  }
  std::cout << std::endl;
#endif
  close(sg_fd);

  bool retval = true;

  if (eresult != 0) {
    if (show_error)
      readIOError(ioerr);
    retval = false;
  }

  if (sresult != 0) {
    if (show_error)
      outputSense(sd);
    retval = false;
  }
  delete sd;
  return retval;
}
void byteswap(unsigned char *array, int size, int value) {
  switch (size) {
  case 2:
    array[0] = (unsigned char)((value & 0xff00) >> 8);
    array[1] = (unsigned char)(value & 0x00ff);
    break;
  case 4:
    array[0] = (unsigned char)((value & 0xff000000) >> 24);
    array[1] = (unsigned char)((value & 0x00ff0000) >> 16);
    array[2] = (unsigned char)((value & 0x0000ff00) >> 8);
    array[3] = (unsigned char)(value & 0x000000ff);

    break;
  default:
    std::cout << "Unhandled byte swap length of " << size << std::endl;
    break;
  }
}

SCSIEncryptOptions::SCSIEncryptOptions() {
  cryptMode = CRYPTMODE_OFF;
  algorithmIndex = DEFAULT_ALGORITHM;
  cryptoKey = {};
  CKOD = false;
  keyName = "";
  rdmc = RDMC_DEFAULT;
}

SSP_NBES::SSP_NBES(const SSP_PAGE_BUFFER *buffer) {
  memset(&nbes, 0, sizeof(SSP_PAGE_NBES));
  memcpy(&nbes, buffer, sizeof(SSP_PAGE_NBES));
  loadKADs(buffer, sizeof(SSP_PAGE_NBES));
}
SSP_DES::SSP_DES(const SSP_PAGE_BUFFER *buffer) {
  memset(&des, 0, sizeof(SSP_PAGE_DES));
  memcpy(&des, buffer, sizeof(SSP_PAGE_DES));
  loadKADs(buffer, sizeof(SSP_PAGE_DES));
}

void KAD_CLASS::loadKADs(const SSP_PAGE_BUFFER *buffer, int start) {
  const char *rawbuff = (const char *)buffer;
  int length = BSSHORT(buffer->length) + 4;
  int pos = start;
  while (pos < length) {
    SSP_KAD kad;
    memset(&kad, 0, sizeof(SSP_KAD));
    memcpy(&kad, rawbuff + pos, SSP_KAD_HEAD_LENGTH);
    pos += SSP_KAD_HEAD_LENGTH;
    if (pos >= length)
      break;
    unsigned short kadDesLen = BSSHORT(kad.descriptorLength);
    if (kadDesLen > 0) {
      memcpy(&kad.descriptor, rawbuff + pos, kadDesLen);
      pos += kadDesLen;
    } else
      pos++;
    kads.push_back(kad);
  }
}
bool moveTape(std::string tapeDevice, int count, bool dirForward) {
  struct mtop mt_command;
  int sg_fd = open(tapeDevice.c_str(), O_RDONLY);
  if (!sg_fd || sg_fd == -1) {
    return false;
  }
  errno = 0;
  bool retval = true;
#if defined(OS_LINUX) || defined(OS_FREEBSD) // Linux or FreeBSD System

  mt_command.mt_op = (dirForward) ? MTFSR : MTBSR;
  mt_command.mt_count = count;
  ioctl(sg_fd, MTIOCTOP, &mt_command);
#elif defined(OS_AIX)
  mt_command.st_op = (dirForward) ? MTFSR : MTBSR;
  mt_command.st_count = count;
  ioctl(sg_fd, STIOCTOP, &mt_command);
#else
#error "OS type is not set"
#endif
  if (errno != 0)
    retval = false;

  close(sg_fd);
  errno = 0;
  return retval;
}

void readIOError(int err) {
  if (err == 0)
    return;
  std::cerr << "ERROR: ";
  switch (err) {
  case EAGAIN:
    std::cerr << "Device already open.\n";
    break;
  case EBUSY:
    std::cerr << "Device Busy.\n";
    break;
  case ETIMEDOUT:
    std::cerr << "Device operation timed out\n";
    break;
  case EIO:
    std::cerr << "Device I/O Error.\n";
    break;
  case EPERM:
    std::cerr << "You do not have privileges to do this.  Are you root?\n";
    break;
#ifdef OS_AIX
  case EBADF:
    std::cerr << "EBADF\n";
    break;
  case EFAULT:
    std::cerr << "EFAULT\n";
    break;
  case EINTR:
    std::cerr << "EINTR\n";
    break;
  case EINVAL:
    std::cerr << "Invalid device.\n";
    break;

  case ENOTTY:
    std::cerr << "ENOTTY\n";
    break;

  case ENODEV:
    std::cerr << "Device is not responding.\n";
    break;

  case ENXIO:
    std::cerr << "ENXIO\n";
    break;

#endif
  default:
    if (errno != 0) {
      std::cerr << "0x" << std::hex << errno << " " << strerror(errno) << "\n";
    }
  }
}
void outputSense(SCSI_PAGE_SENSE *sd) {
  std::cerr << std::left << std::setw(25) << "Sense Code: ";

  switch ((int)sd->senseKey) {
  case 0:
    std::cerr << "No specific error";
    break;
  case 2:
    std::cerr << "Device not ready";
    break;
  case 3:
    std::cerr << "Medium Error";
    break;
  case 4:
    std::cerr << "Hardware Error";
    break;
  case 5:
    std::cerr << "Illegal Request";
    break;
  case 6:
    std::cerr << "Unit Attention";
    break;
  case 7:
    std::cerr << "Data protect";
    break;
  case 8:
    std::cerr << "Blank tape";
    break;
  }

  std::cerr << " (0x" << HEX(sd->senseKey) << ")\n";

  std::cerr << std::left << std::setw(25) << " ASC:"
            << "0x" << HEX(sd->addSenseCode) << "\n";

  std::cerr << std::left << std::setw(25) << " ASCQ:"
            << "0x" << HEX(sd->addSenseCodeQual) << "\n";

  if (sd->addSenseLen > 0) {
    std::cerr << std::left << std::setw(25) << " Additional data:" 
    		<< "0x";

    for (int i = 0; i < sd->addSenseLen; i++) {
      std::cerr <<  HEX(sd->addSenseData[i]);
    }
    std::cerr << "\n";
  }
#ifdef DEBUGSCSI
  std::cerr << std::left << std::setw(25) << " Raw Sense:"
            << "0x";
  char *rawsense = (char *)sd;

  for (int i = 0; i < sizeof(SCSI_PAGE_SENSE); i++) {
    std::cerr << HEX(rawsense[i]);
  }
  std::cerr << "\n";
#endif
}