//-----------------------------------------------------------------------------
// Copyright (C) 2010 iZsh <izsh at fail0verflow.com>
//
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// High frequency Legic commands
//-----------------------------------------------------------------------------

#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include "proxmark3.h"
#include "data.h"
#include "ui.h"
#include "cmdparser.h"
#include "cmdhflegic.h"
#include "cmdmain.h"
#include "util.h"
static int CmdHelp(const char *Cmd);

static command_t CommandTable[] = 
{
  {"help",        CmdHelp,        1, "This help"},
  {"decode",      CmdLegicDecode, 0, "Display deobfuscated and decoded LEGIC RF tag data (use after hf legic reader)"},
  {"reader",      CmdLegicRFRead, 0, "[offset [length]] -- read bytes from a LEGIC card"},
  {"save",        CmdLegicSave,   0, "<filename> [<length>] -- Store samples"},
  {"load",        CmdLegicLoad,   0, "<filename> -- Restore samples"},
  {"sim",         CmdLegicRfSim,  0, "[phase drift [frame drift [req/resp drift]]] Start tag simulator (use after load or read)"},
  {"write",       CmdLegicRfWrite,0, "<offset> <length> -- Write sample buffer (user after load or read)"},
  {"fill",        CmdLegicRfFill, 0, "<offset> <length> <value> -- Fill/Write tag with constant value"},
  {NULL, NULL, 0, NULL}
};

int CmdHFLegic(const char *Cmd)
{
  CmdsParse(CommandTable, Cmd);
  return 0;
}

int CmdHelp(const char *Cmd)
{
  CmdsHelp(CommandTable);
  return 0;
}

/*
 *  Output BigBuf and deobfuscate LEGIC RF tag data.
 *   This is based on information given in the talk held
 *  by Henryk Ploetz and Karsten Nohl at 26c3
 */
int CmdLegicDecode(const char *Cmd)
{
  int i, j, k, n;
  int segment_len = 0;
  int segment_flag = 0;
  int stamp_len = 0;
  int crc = 0;
  int wrp = 0;
  int wrc = 0;
  uint8_t data_buf[1052]; // receiver buffer
  char out_string[3076]; // just use big buffer - bad practice
  char token_type[4];
  
  // copy data from proxmark into buffer
   GetFromBigBuf(data_buf,sizeof(data_buf),0);
   WaitForResponse(CMD_ACK,NULL);
    
  // Output CDF System area (9 bytes) plus remaining header area (12 bytes)
  
  PrintAndLog("\nCDF: System Area");
  
  PrintAndLog("MCD: %02x, MSN: %02x %02x %02x, MCC: %02x",
    data_buf[0],
    data_buf[1],
    data_buf[2],
    data_buf[3],
    data_buf[4]
  );
  
  crc = data_buf[4];
 
  switch (data_buf[5]&0x7f) {
    case 0x00 ... 0x2f:
      strncpy(token_type, "IAM",sizeof(token_type));
      break;
    case 0x30 ... 0x6f:
      strcpy(token_type, "SAM");
      break;
    case 0x70 ... 0x7f:
      strcpy(token_type, "GAM");
      break;
    default:
      strcpy(token_type, "???");
      break;
  }
  
  stamp_len = 0xfc - data_buf[6];
  
  PrintAndLog("DCF: %02x %02x, Token_Type=%s (OLE=%01u), Stamp_len=%02u",
    data_buf[5],
    data_buf[6],
    token_type,
    (data_buf[5]&0x80)>>7,
    stamp_len
  );
  
  PrintAndLog("WRP=%02u, WRC=%01u, RD=%01u, raw=%02x, SSC=%02x",
    data_buf[7]&0x0f,
    (data_buf[7]&0x70)>>4,
    (data_buf[7]&0x80)>>7,
    data_buf[7],
    data_buf[8]
  );
  
  PrintAndLog("Remaining Header Area");
  
  PrintAndLog("%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
      data_buf[9],
    data_buf[10],
    data_buf[11],
    data_buf[12],
    data_buf[13],
    data_buf[14],
    data_buf[15],
    data_buf[16],
    data_buf[17],
    data_buf[18],
    data_buf[19],
    data_buf[20],
    data_buf[21]
  );
  
  PrintAndLog("\nADF: User Area");
  
  i = 22;  
  for (n=0; n<64; n++) {
    segment_len = ((data_buf[i+1]^crc)&0x0f) * 256 + (data_buf[i]^crc);
    segment_flag = ((data_buf[i+1]^crc)&0xf0)>>4;
    
    wrp = (data_buf[i+2]^crc);
    wrc = ((data_buf[i+3]^crc)&0x70)>>4;
    
     PrintAndLog("Segment %02u: raw header=%02x %02x %02x %02x, flag=%01x (valid=%01u, last=%01u), len=%04u, WRP=%02u, WRC=%02u, RD=%01u, CRC=%02x",
      n,
      data_buf[i]^crc,
      data_buf[i+1]^crc,
      data_buf[i+2]^crc,
      data_buf[i+3]^crc,
      segment_flag,
      (segment_flag&0x4)>>2,
      (segment_flag&0x8)>>3,
      segment_len,
      wrp,
      wrc,
      ((data_buf[i+3]^crc)&0x80)>>7,
      (data_buf[i+4]^crc)
    );
    
    i+=5;
    
    if (wrc>0) {
      PrintAndLog("WRC protected area:");
      for (k=0, j=0; k < wrc && j<(sizeof(out_string)-3); k++, i++, j += 3) {
        sprintf(&out_string[j], "%02x", (data_buf[i]^crc));
        out_string[j+2] = ' ';
      };
        
      out_string[j] = '\0';
    
      PrintAndLog("%s", out_string);
    }
    
    if (wrp>wrc) {
      PrintAndLog("Remaining write protected area:");
      
      for (k=0, j=0; k < (wrp-wrc) && j<(sizeof(out_string)-3); k++, i++, j += 3) {
        sprintf(&out_string[j], "%02x", (data_buf[i]^crc));
        out_string[j+2] = ' ';
      };
    
      out_string[j] = '\0';
    
      PrintAndLog("%s", out_string);
      if((wrp-wrc) == 8) {
        sprintf(out_string,"Card ID: %2X%02X%02X",data_buf[i-4]^crc,data_buf[i-3]^crc,data_buf[i-2]^crc);
        PrintAndLog("%s", out_string);
      }
    }
    
    PrintAndLog("Remaining segment payload:");
    for (k=0, j=0; k < (segment_len - wrp - 5) && j<(sizeof(out_string)-3); k++, i++, j += 3) {
      sprintf(&out_string[j], "%02x", (data_buf[i]^crc));
      out_string[j+2] = ' ';
    };
    
    out_string[j] = '\0';
    
    PrintAndLog("%s", out_string);
    
    // end with last segment
    if (segment_flag & 0x8)
      return 0;
  };
  return 0;
}

int CmdLegicRFRead(const char *Cmd)
{
  int byte_count=0,offset=0;
  sscanf(Cmd, "%i %i", &offset, &byte_count);
  if(byte_count == 0) byte_count = -1;
  if(byte_count + offset > 1024) byte_count = 1024 - offset;
  UsbCommand c={CMD_READER_LEGIC_RF, {offset, byte_count, 0}};
  SendCommand(&c);
  return 0;
}

int CmdLegicLoad(const char *Cmd)
{
	char filename[FILE_PATH_SIZE] = {0x00};
	int len = 0;
	
	if (param_getchar(Cmd, 0) == 'h' || param_getchar(Cmd, 0)== 0x00) {
		PrintAndLog("It loads datasamples from the file `filename`");
		PrintAndLog("Usage:  hf legic load <file name>");
		PrintAndLog(" sample: hf legic load filename");
		return 0;
	}

	len = strlen(Cmd);	
	if (len > FILE_PATH_SIZE) {
		PrintAndLog("Filepath too long (was %s bytes), max allowed is %s ", len, FILE_PATH_SIZE);
		return 0;
	}
	memcpy(filename, Cmd, len);

    FILE *f = fopen(filename, "r");
    if(!f) {
        PrintAndLog("couldn't open '%s'", Cmd);
        return -1;
    }
    char line[80]; int offset = 0; unsigned int data[8];
    while(fgets(line, sizeof(line), f)) {
        int res = sscanf(line, "%x %x %x %x %x %x %x %x", 
            &data[0], &data[1], &data[2], &data[3],
            &data[4], &data[5], &data[6], &data[7]);
        if(res != 8) {
          PrintAndLog("Error: could not read samples");
          fclose(f);
          return -1;
        }
        UsbCommand c={CMD_DOWNLOADED_SIM_SAMPLES_125K, {offset, 0, 0}};
        int j; for(j = 0; j < 8; j++) {
            c.d.asBytes[j] = data[j];
        }
        SendCommand(&c);
        WaitForResponse(CMD_ACK, NULL);
        offset += 8;
    }
    fclose(f);
    PrintAndLog("loaded %u samples", offset);
    return 0;
}

int CmdLegicSave(const char *Cmd)
{
  int requested = 1024;
  int offset = 0;
  int delivered = 0;
  char filename[FILE_PATH_SIZE];
  uint8_t got[1024];
  
  sscanf(Cmd, " %s %i %i", filename, &requested, &offset);

  /* If no length given save entire legic read buffer */
  /* round up to nearest 8 bytes so the saved data can be used with legicload */
  if (requested == 0) {
    requested = 1024;
  }
  if (requested % 8 != 0) {
    int remainder = requested % 8;
    requested = requested + 8 - remainder;
  }
  if (offset + requested > sizeof(got)) {
    PrintAndLog("Tried to read past end of buffer, <bytes> + <offset> > 1024");
    return 0;
  }
  
  FILE *f = fopen(filename, "w");
  if(!f) {
    PrintAndLog("couldn't open '%s'", Cmd+1);
    return -1;
  }

  GetFromBigBuf(got,requested,offset);
  WaitForResponse(CMD_ACK,NULL);

  for (int j = 0; j < requested; j += 8) {
    fprintf(f, "%02x %02x %02x %02x %02x %02x %02x %02x\n",
      got[j+0],
      got[j+1],
      got[j+2],
      got[j+3],
      got[j+4],
      got[j+5],
      got[j+6],
      got[j+7]
    );
    delivered += 8;
    if (delivered >= requested)
      break;
  }

  fclose(f);
  PrintAndLog("saved %u samples", delivered);
  return 0;
}

int CmdLegicRfSim(const char *Cmd)
{
   UsbCommand c={CMD_SIMULATE_TAG_LEGIC_RF};
   c.arg[0] = 6;
   c.arg[1] = 3;
   c.arg[2] = 0;
   sscanf(Cmd, " %" SCNi64 " %" SCNi64 " %" SCNi64, &c.arg[0], &c.arg[1], &c.arg[2]);
   SendCommand(&c);
   return 0;
}

int CmdLegicRfWrite(const char *Cmd)
{
    UsbCommand c={CMD_WRITER_LEGIC_RF};
    int res = sscanf(Cmd, " 0x%" SCNx64 " 0x%" SCNx64, &c.arg[0], &c.arg[1]);
	if(res != 2) {
		PrintAndLog("Please specify the offset and length as two hex strings");
        return -1;
    }
    SendCommand(&c);
    return 0;
}

int CmdLegicRfFill(const char *Cmd)
{
    UsbCommand cmd ={CMD_WRITER_LEGIC_RF};
    int res = sscanf(Cmd, " 0x%" SCNx64 " 0x%" SCNx64 " 0x%" SCNx64, &cmd.arg[0], &cmd.arg[1], &cmd.arg[2]);
    if(res != 3) {
        PrintAndLog("Please specify the offset, length and value as two hex strings");
        return -1;
    }

    int i;
    UsbCommand c={CMD_DOWNLOADED_SIM_SAMPLES_125K, {0, 0, 0}};
    for(i = 0; i < 48; i++) {
      c.d.asBytes[i] = cmd.arg[2];
    }
    for(i = 0; i < 22; i++) {
      c.arg[0] = i*48;
      SendCommand(&c);
      WaitForResponse(CMD_ACK,NULL);
    }
    SendCommand(&cmd);
    return 0;
 }