#include "cmd.h"
#include "proxmark3.h"
#include "apps.h"
+#include "fpga.h"
#include "util.h"
#include "printf.h"
#include "string.h"
#include "legicrf.h"
+#include "legicrfsim.h"
#include "hitag2.h"
#include "hitagS.h"
#include "lfsampling.h"
#include "BigBuf.h"
#include "mifareutil.h"
#include "pcf7931.h"
+#include "i2c.h"
#ifdef WITH_LCD
#include "LCD.h"
#endif
+
// Craig Young - 14a stand-alone code
-#ifdef WITH_ISO14443a_StandAlone
+#ifdef WITH_ISO14443a
#include "iso14443a.h"
#endif
static int ReadAdc(int ch)
{
// Note: ADC_MODE_PRESCALE and ADC_MODE_SAMPLE_HOLD_TIME are set to the maximum allowed value.
- // AMPL_HI is are high impedance (10MOhm || 1MOhm) output, the input capacitance of the ADC is 12pF (typical). This results in a time constant
+ // AMPL_HI is a high impedance (10MOhm || 1MOhm) output, the input capacitance of the ADC is 12pF (typical). This results in a time constant
// of RC = (0.91MOhm) * 12pF = 10.9us. Even after the maximum configurable sample&hold time of 40us the input capacitor will not be fully charged.
//
// The maths are:
while(!(AT91C_BASE_ADC->ADC_SR & ADC_END_OF_CONVERSION(ch))) {};
- return AT91C_BASE_ADC->ADC_CDR[ch];
+ return AT91C_BASE_ADC->ADC_CDR[ch] & 0x3ff;
}
int AvgAdc(int ch) // was static - merlok
return (a + 15) >> 5;
}
+static int AvgAdc_Voltage_HF(void)
+{
+ int AvgAdc_Voltage_Low, AvgAdc_Voltage_High;
+
+ AvgAdc_Voltage_Low= (MAX_ADC_HF_VOLTAGE_LOW * AvgAdc(ADC_CHAN_HF_LOW)) >> 10;
+ // if voltage range is about to be exceeded, use high voltage ADC channel if available (RDV40 only)
+ if (AvgAdc_Voltage_Low > MAX_ADC_HF_VOLTAGE_LOW - 300) {
+ AvgAdc_Voltage_High = (MAX_ADC_HF_VOLTAGE_HIGH * AvgAdc(ADC_CHAN_HF_HIGH)) >> 10;
+ if (AvgAdc_Voltage_High >= AvgAdc_Voltage_Low) {
+ return AvgAdc_Voltage_High;
+ }
+ }
+ return AvgAdc_Voltage_Low;
+}
+
+static int AvgAdc_Voltage_LF(void)
+{
+ return (MAX_ADC_LF_VOLTAGE * AvgAdc(ADC_CHAN_LF)) >> 10;
+}
+
void MeasureAntennaTuningLfOnly(int *vLf125, int *vLf134, int *peakf, int *peakv, uint8_t LF_Results[])
{
int i, adcval = 0, peak = 0;
WDT_HIT();
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, i);
SpinDelay(20);
- adcval = ((MAX_ADC_LF_VOLTAGE * AvgAdc(ADC_CHAN_LF)) >> 10);
+ adcval = AvgAdc_Voltage_LF();
if (i==95) *vLf125 = adcval; // voltage at 125Khz
if (i==89) *vLf134 = adcval; // voltage at 134Khz
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
SpinDelay(20);
- *vHf = (MAX_ADC_HF_VOLTAGE * AvgAdc(ADC_CHAN_HF)) >> 10;
+ *vHf = AvgAdc_Voltage_HF();
LED_A_OFF();
-
return;
}
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
for (;;) {
- SpinDelay(20);
- vHf = (MAX_ADC_HF_VOLTAGE * AvgAdc(ADC_CHAN_HF)) >> 10;
+ SpinDelay(500);
+ vHf = AvgAdc_Voltage_HF();
Dbprintf("%d mV",vHf);
if (BUTTON_PRESS()) break;
extern struct version_information version_information;
/* bootrom version information is pointed to from _bootphase1_version_pointer */
extern char *_bootphase1_version_pointer, _flash_start, _flash_end, _bootrom_start, _bootrom_end, __data_src_start__;
+
+
void SendVersion(void)
{
char temp[USB_CMD_DATA_SIZE]; /* Limited data payload in USB packets */
FormatVersionInformation(temp, sizeof(temp), "os: ", &version_information);
strncat(VersionString, temp, sizeof(VersionString) - strlen(VersionString) - 1);
- FpgaGatherVersion(FPGA_BITSTREAM_LF, temp, sizeof(temp));
- strncat(VersionString, temp, sizeof(VersionString) - strlen(VersionString) - 1);
- FpgaGatherVersion(FPGA_BITSTREAM_HF, temp, sizeof(temp));
- strncat(VersionString, temp, sizeof(VersionString) - strlen(VersionString) - 1);
-
+ for (int i = 0; i < fpga_bitstream_num; i++) {
+ strncat(VersionString, fpga_version_information[i], sizeof(VersionString) - strlen(VersionString) - 1);
+ strncat(VersionString, "\n", sizeof(VersionString) - strlen(VersionString) - 1);
+ }
+
+ // test availability of SmartCard slot
+ if (I2C_is_available()) {
+ strncat(VersionString, "SmartCard Slot: available\n", sizeof(VersionString) - strlen(VersionString) - 1);
+ } else {
+ strncat(VersionString, "SmartCard Slot: not available\n", sizeof(VersionString) - strlen(VersionString) - 1);
+ }
+
// Send Chip ID and used flash memory
uint32_t text_and_rodata_section_size = (uint32_t)&__data_src_start__ - (uint32_t)&_flash_start;
uint32_t compressed_data_section_size = common_area.arg1;
{
BigBuf_print_status();
Fpga_print_status();
+#ifdef WITH_SMARTCARD
+ I2C_print_status();
+#endif
printConfig(); //LF Sampling config
printUSBSpeed();
Dbprintf("Various");
- Dbprintf(" MF_DBGLEVEL......%d", MF_DBGLEVEL);
- Dbprintf(" ToSendMax........%d",ToSendMax);
- Dbprintf(" ToSendBit........%d",ToSendBit);
+ Dbprintf(" MF_DBGLEVEL........%d", MF_DBGLEVEL);
+ Dbprintf(" ToSendMax..........%d", ToSendMax);
+ Dbprintf(" ToSendBit..........%d", ToSendBit);
cmd_send(CMD_ACK,1,0,0,0,0);
}
-#if defined(WITH_ISO14443a_StandAlone) || defined(WITH_LF)
+#if defined(WITH_ISO14443a_StandAlone) || defined(WITH_LF_StandAlone)
#define OPTS 2
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
int selected = 0;
- int playing = 0, iGotoRecord = 0, iGotoClone = 0;
- int cardRead[OPTS] = {0};
+ bool playing = false, GotoRecord = false, GotoClone = false;
+ bool cardRead[OPTS] = {false};
uint8_t readUID[10] = {0};
uint32_t uid_1st[OPTS]={0};
uint32_t uid_2nd[OPTS]={0};
WDT_HIT();
SpinDelay(300);
- if (iGotoRecord == 1 || cardRead[selected] == 0)
+ if (GotoRecord || !cardRead[selected])
{
- iGotoRecord = 0;
+ GotoRecord = false;
LEDsoff();
LED(selected + 1, 0);
LED(LED_RED2, 0);
else if (cardRead[(selected+1)%OPTS]) {
Dbprintf("Button press detected but no card in bank[%d] so playing from bank[%d]", selected, (selected+1)%OPTS);
selected = (selected+1)%OPTS;
- break; // playing = 1;
+ break;
}
else {
Dbprintf("Button press detected but no stored tag to play. (Ignoring button)");
LED(selected + 1, 0);
// Next state is replay:
- playing = 1;
+ playing = true;
- cardRead[selected] = 1;
+ cardRead[selected] = true;
}
/* MF Classic UID clone */
- else if (iGotoClone==1)
+ else if (GotoClone)
{
- iGotoClone=0;
+ GotoClone=false;
LEDsoff();
LED(selected + 1, 0);
LED(LED_ORANGE, 250);
MifareCGetBlock(0x3F, 1, 0, oldBlock0);
if (oldBlock0[0] == 0 && oldBlock0[0] == oldBlock0[1] && oldBlock0[1] == oldBlock0[2] && oldBlock0[2] == oldBlock0[3]) {
Dbprintf("No changeable tag detected. Returning to replay mode for bank[%d]", selected);
- playing = 1;
+ playing = true;
}
else {
Dbprintf("UID from target tag: %02X%02X%02X%02X", oldBlock0[0],oldBlock0[1],oldBlock0[2],oldBlock0[3]);
if (memcmp(testBlock0,newBlock0,16)==0)
{
DbpString("Cloned successfull!");
- cardRead[selected] = 0; // Only if the card was cloned successfully should we clear it
- playing = 0;
- iGotoRecord = 1;
+ cardRead[selected] = false; // Only if the card was cloned successfully should we clear it
+ playing = false;
+ GotoRecord = true;
selected = (selected+1) % OPTS;
}
else {
Dbprintf("Clone failed. Back to replay mode on bank[%d]", selected);
- playing = 1;
+ playing = true;
}
}
LEDsoff();
}
// Change where to record (or begin playing)
- else if (playing==1) // button_pressed == BUTTON_SINGLE_CLICK && cardRead[selected])
+ else if (playing) // button_pressed == BUTTON_SINGLE_CLICK && cardRead[selected])
{
LEDsoff();
LED(selected + 1, 0);
// Begin transmitting
- if (playing)
- {
- LED(LED_GREEN, 0);
- DbpString("Playing");
- for ( ; ; ) {
- WDT_HIT();
- int button_action = BUTTON_HELD(1000);
- if (button_action == 0) { // No button action, proceed with sim
- uint8_t data[512] = {0}; // in case there is a read command received we shouldn't break
- Dbprintf("Simulating ISO14443a tag with uid[0]: %08x, uid[1]: %08x [Bank: %u]", uid_1st[selected],uid_2nd[selected],selected);
- if (hi14a_card[selected].sak == 8 && hi14a_card[selected].atqa[0] == 4 && hi14a_card[selected].atqa[1] == 0) {
- DbpString("Mifare Classic");
- SimulateIso14443aTag(1,uid_1st[selected], uid_2nd[selected], data); // Mifare Classic
- }
- else if (hi14a_card[selected].sak == 0 && hi14a_card[selected].atqa[0] == 0x44 && hi14a_card[selected].atqa[1] == 0) {
- DbpString("Mifare Ultralight");
- SimulateIso14443aTag(2,uid_1st[selected],uid_2nd[selected],data); // Mifare Ultralight
- }
- else if (hi14a_card[selected].sak == 20 && hi14a_card[selected].atqa[0] == 0x44 && hi14a_card[selected].atqa[1] == 3) {
- DbpString("Mifare DESFire");
- SimulateIso14443aTag(3,uid_1st[selected],uid_2nd[selected],data); // Mifare DESFire
- }
- else {
- Dbprintf("Unrecognized tag type -- defaulting to Mifare Classic emulation");
- SimulateIso14443aTag(1,uid_1st[selected], uid_2nd[selected], data);
- }
+ LED(LED_GREEN, 0);
+ DbpString("Playing");
+ for ( ; ; ) {
+ WDT_HIT();
+ int button_action = BUTTON_HELD(1000);
+ if (button_action == 0) { // No button action, proceed with sim
+ uint8_t data[512] = {0}; // in case there is a read command received we shouldn't break
+ Dbprintf("Simulating ISO14443a tag with uid[0]: %08x, uid[1]: %08x [Bank: %u]", uid_1st[selected],uid_2nd[selected],selected);
+ if (hi14a_card[selected].sak == 8 && hi14a_card[selected].atqa[0] == 4 && hi14a_card[selected].atqa[1] == 0) {
+ DbpString("Mifare Classic");
+ SimulateIso14443aTag(1,uid_1st[selected], uid_2nd[selected], data); // Mifare Classic
}
- else if (button_action == BUTTON_SINGLE_CLICK) {
- selected = (selected + 1) % OPTS;
- Dbprintf("Done playing. Switching to record mode on bank %d",selected);
- iGotoRecord = 1;
- break;
+ else if (hi14a_card[selected].sak == 0 && hi14a_card[selected].atqa[0] == 0x44 && hi14a_card[selected].atqa[1] == 0) {
+ DbpString("Mifare Ultralight");
+ SimulateIso14443aTag(2,uid_1st[selected],uid_2nd[selected],data); // Mifare Ultralight
}
- else if (button_action == BUTTON_HOLD) {
- Dbprintf("Playtime over. Begin cloning...");
- iGotoClone = 1;
- break;
+ else if (hi14a_card[selected].sak == 20 && hi14a_card[selected].atqa[0] == 0x44 && hi14a_card[selected].atqa[1] == 3) {
+ DbpString("Mifare DESFire");
+ SimulateIso14443aTag(3,uid_1st[selected],uid_2nd[selected],data); // Mifare DESFire
+ }
+ else {
+ Dbprintf("Unrecognized tag type -- defaulting to Mifare Classic emulation");
+ SimulateIso14443aTag(1,uid_1st[selected], uid_2nd[selected], data);
}
- WDT_HIT();
}
-
- /* We pressed a button so ignore it here with a delay */
- SpinDelay(300);
- LEDsoff();
- LED(selected + 1, 0);
+ else if (button_action == BUTTON_SINGLE_CLICK) {
+ selected = (selected + 1) % OPTS;
+ Dbprintf("Done playing. Switching to record mode on bank %d",selected);
+ GotoRecord = true;
+ break;
+ }
+ else if (button_action == BUTTON_HOLD) {
+ Dbprintf("Playtime over. Begin cloning...");
+ GotoClone = true;
+ break;
+ }
+ WDT_HIT();
}
- else
- while(BUTTON_PRESS())
- WDT_HIT();
+
+ /* We pressed a button so ignore it here with a delay */
+ SpinDelay(300);
+ LEDsoff();
+ LED(selected + 1, 0);
}
}
}
-#elif WITH_LF
+#elif WITH_LF_StandAlone
// samy's sniff and repeat routine
void SamyRun()
{
StandAloneMode();
FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
- int high[OPTS], low[OPTS];
+ int tops[OPTS], high[OPTS], low[OPTS];
int selected = 0;
int playing = 0;
int cardRead = 0;
/* need this delay to prevent catching some weird data */
SpinDelay(500);
- CmdHIDdemodFSK(1, &high[selected], &low[selected], 0);
- Dbprintf("Recorded %x %x%08x", selected, high[selected], low[selected]);
+ CmdHIDdemodFSK(1, &tops[selected], &high[selected], &low[selected], 0);
+ if (tops[selected] > 0)
+ Dbprintf("Recorded %x %x%08x%08x", selected, tops[selected], high[selected], low[selected]);
+ else
+ Dbprintf("Recorded %x %x%08x", selected, high[selected], low[selected]);
LEDsoff();
LED(selected + 1, 0);
LED(LED_ORANGE, 0);
// record
- Dbprintf("Cloning %x %x%08x", selected, high[selected], low[selected]);
+ if (tops[selected] > 0)
+ Dbprintf("Cloning %x %x%08x%08x", selected, tops[selected], high[selected], low[selected]);
+ else
+ Dbprintf("Cloning %x %x%08x", selected, high[selected], low[selected]);
// wait for button to be released
while(BUTTON_PRESS())
/* need this delay to prevent catching some weird data */
SpinDelay(500);
- CopyHIDtoT55x7(0, high[selected], low[selected], 0);
- Dbprintf("Cloned %x %x%08x", selected, high[selected], low[selected]);
+ CopyHIDtoT55x7(tops[selected] & 0x000FFFFF, high[selected], low[selected], (tops[selected] != 0 && ((high[selected]& 0xFFFFFFC0) != 0)));
+ if (tops[selected] > 0)
+ Dbprintf("Cloned %x %x%08x%08x", selected, tops[selected], high[selected], low[selected]);
+ else
+ Dbprintf("Cloned %x %x%08x", selected, high[selected], low[selected]);
LEDsoff();
LED(selected + 1, 0);
// wait for button to be released
while(BUTTON_PRESS())
WDT_HIT();
- Dbprintf("%x %x%08x", selected, high[selected], low[selected]);
- CmdHIDsimTAG(high[selected], low[selected], 0);
+ if (tops[selected] > 0)
+ Dbprintf("%x %x%08x%08x", selected, tops[selected], high[selected], low[selected]);
+ else
+ Dbprintf("%x %x%08x", selected, high[selected], low[selected]);
+
+ CmdHIDsimTAG(tops[selected], high[selected], low[selected], 0);
DbpString("Done playing");
if (BUTTON_HELD(1000) > 0)
{
void ListenReaderField(int limit)
{
- int lf_av, lf_av_new, lf_baseline= 0, lf_max;
- int hf_av, hf_av_new, hf_baseline= 0, hf_max;
+ int lf_av, lf_av_new=0, lf_baseline= 0, lf_max;
+ int hf_av, hf_av_new=0, hf_baseline= 0, hf_max;
int mode=1, display_val, display_max, i;
-#define LF_ONLY 1
-#define HF_ONLY 2
-#define REPORT_CHANGE 10 // report new values only if they have changed at least by REPORT_CHANGE
+#define LF_ONLY 1
+#define HF_ONLY 2
+#define REPORT_CHANGE_PERCENT 5 // report new values only if they have changed at least by REPORT_CHANGE_PERCENT
+#define MIN_HF_FIELD 300 // in mode 1 signal HF field greater than MIN_HF_FIELD above baseline
+#define MIN_LF_FIELD 1200 // in mode 1 signal LF field greater than MIN_LF_FIELD above baseline
// switch off FPGA - we don't want to measure our own signal
LEDsoff();
- lf_av = lf_max = AvgAdc(ADC_CHAN_LF);
+ lf_av = lf_max = AvgAdc_Voltage_LF();
if(limit != HF_ONLY) {
- Dbprintf("LF 125/134kHz Baseline: %dmV", (MAX_ADC_LF_VOLTAGE * lf_av) >> 10);
+ Dbprintf("LF 125/134kHz Baseline: %dmV", lf_av);
lf_baseline = lf_av;
}
- hf_av = hf_max = AvgAdc(ADC_CHAN_HF);
-
+ hf_av = hf_max = AvgAdc_Voltage_HF();
+
if (limit != LF_ONLY) {
- Dbprintf("HF 13.56MHz Baseline: %dmV", (MAX_ADC_HF_VOLTAGE * hf_av) >> 10);
+ Dbprintf("HF 13.56MHz Baseline: %dmV", hf_av);
hf_baseline = hf_av;
}
for(;;) {
+ SpinDelay(500);
if (BUTTON_PRESS()) {
- SpinDelay(500);
switch (mode) {
case 1:
mode=2;
return;
break;
}
+ while (BUTTON_PRESS());
}
WDT_HIT();
if (limit != HF_ONLY) {
if(mode == 1) {
- if (ABS(lf_av - lf_baseline) > REPORT_CHANGE)
+ if (lf_av - lf_baseline > MIN_LF_FIELD)
LED_D_ON();
else
LED_D_OFF();
}
- lf_av_new = AvgAdc(ADC_CHAN_LF);
+ lf_av_new = AvgAdc_Voltage_LF();
// see if there's a significant change
- if(ABS(lf_av - lf_av_new) > REPORT_CHANGE) {
- Dbprintf("LF 125/134kHz Field Change: %5dmV", (MAX_ADC_LF_VOLTAGE * lf_av_new) >> 10);
+ if (ABS((lf_av - lf_av_new)*100/(lf_av?lf_av:1)) > REPORT_CHANGE_PERCENT) {
+ Dbprintf("LF 125/134kHz Field Change: %5dmV", lf_av_new);
lf_av = lf_av_new;
if (lf_av > lf_max)
lf_max = lf_av;
if (limit != LF_ONLY) {
if (mode == 1){
- if (ABS(hf_av - hf_baseline) > REPORT_CHANGE)
+ if (hf_av - hf_baseline > MIN_HF_FIELD)
LED_B_ON();
else
LED_B_OFF();
}
- hf_av_new = AvgAdc(ADC_CHAN_HF);
+ hf_av_new = AvgAdc_Voltage_HF();
+
// see if there's a significant change
- if(ABS(hf_av - hf_av_new) > REPORT_CHANGE) {
- Dbprintf("HF 13.56MHz Field Change: %5dmV", (MAX_ADC_HF_VOLTAGE * hf_av_new) >> 10);
+ if (ABS((hf_av - hf_av_new)*100/(hf_av?hf_av:1)) > REPORT_CHANGE_PERCENT) {
+ Dbprintf("HF 13.56MHz Field Change: %5dmV", hf_av_new);
hf_av = hf_av_new;
if (hf_av > hf_max)
hf_max = hf_av;
cmd_send(CMD_ACK,SnoopLF(),0,0,0,0);
break;
case CMD_HID_DEMOD_FSK:
- CmdHIDdemodFSK(c->arg[0], 0, 0, 1);
+ CmdHIDdemodFSK(c->arg[0], 0, 0, 0, 1);
break;
case CMD_HID_SIM_TAG:
- CmdHIDsimTAG(c->arg[0], c->arg[1], 1);
+ CmdHIDsimTAG(c->arg[0], c->arg[1], c->arg[2], 1);
break;
case CMD_FSK_SIM_TAG:
CmdFSKsimTAG(c->arg[0], c->arg[1], c->arg[2], c->d.asBytes);
SimulateHitagSTag((bool)c->arg[0],(byte_t*)c->d.asBytes);
break;
case CMD_TEST_HITAGS_TRACES:// Tests every challenge within the given file
- check_challenges((bool)c->arg[0],(byte_t*)c->d.asBytes);
+ check_challenges_cmd((bool)c->arg[0], (byte_t*)c->d.asBytes, (uint8_t)c->arg[1]);
break;
case CMD_READ_HITAG_S://Reader for only Hitag S tags, args = key or challenge
- ReadHitagS((hitag_function)c->arg[0],(hitag_data*)c->d.asBytes);
+ ReadHitagSCmd((hitag_function)c->arg[0], (hitag_data*)c->d.asBytes, (uint8_t)c->arg[1], (uint8_t)c->arg[2], false);
+ break;
+ case CMD_READ_HITAG_S_BLK:
+ ReadHitagSCmd((hitag_function)c->arg[0], (hitag_data*)c->d.asBytes, (uint8_t)c->arg[1], (uint8_t)c->arg[2], true);
break;
case CMD_WR_HITAG_S://writer for Hitag tags args=data to write,page and key or challenge
if ((hitag_function)c->arg[0] < 10) {
#ifdef WITH_LEGICRF
case CMD_SIMULATE_TAG_LEGIC_RF:
- LegicRfSimulate(c->arg[0], c->arg[1], c->arg[2]);
+ LegicRfSimulate(c->arg[0]);
break;
case CMD_WRITER_LEGIC_RF:
HfSnoop(c->arg[0], c->arg[1]);
break;
#endif
+#ifdef WITH_SMARTCARD
+ case CMD_SMART_ATR: {
+ SmartCardAtr();
+ break;
+ }
+ case CMD_SMART_SETCLOCK:{
+ SmartCardSetClock(c->arg[0]);
+ break;
+ }
+ case CMD_SMART_RAW: {
+ SmartCardRaw(c->arg[0], c->arg[1], c->d.asBytes);
+ break;
+ }
+ case CMD_SMART_UPLOAD: {
+ // upload file from client
+ uint8_t *mem = BigBuf_get_addr();
+ memcpy( mem + c->arg[0], c->d.asBytes, USB_CMD_DATA_SIZE);
+ cmd_send(CMD_ACK,1,0,0,0,0);
+ break;
+ }
+ case CMD_SMART_UPGRADE: {
+ SmartCardUpgrade(c->arg[0]);
+ break;
+ }
+#endif
case CMD_BUFF_CLEAR:
BigBuf_Clear();
LED_A_OFF();
// Init USB device
- usb_enable();
+ usb_enable();
// The FPGA gets its clock from us from PCK0 output, so set that up.
AT91C_BASE_PIOA->PIO_BSR = GPIO_PCK0;
}
WDT_HIT();
-#ifdef WITH_LF
+#ifdef WITH_LF_StandAlone
#ifndef WITH_ISO14443a_StandAlone
if (BUTTON_HELD(1000) > 0)
SamyRun();
projects / proxmark3-svn / blobdiff