sniffing: move conversion convertion and flag processing from ISR to main loop to keep ISR fast and focus on data capture

Change-Id: Ieefa8a5f81dbcc12c1ad3059660dbffa0c1a4961
This commit is contained in:
Kévin Redon
2018-07-03 16:10:04 +02:00
committed by King Kévin
parent 30f90a78fc
commit 709a431ab9
2 changed files with 88 additions and 64 deletions

View File

@@ -19,8 +19,7 @@
*/
/* This code implement the Sniffer mode to sniff the communication between a SIM card (or any ISO 7816 smart card) and a phone (or any ISO 7816 card reader).
* For historical reasons (i.e. SIMtrace hardware) the USART peripheral connected to the SIM card is used.
* TODO handle RST, PTS, and send data over USB
* TODO put common ISO7816-3 code is separate library (and combine clean with iso7816_4)
* TODO put common ISO7816-3 code is separate library (and combine clean with iso7816_4)
*/
#include "board.h"
#include "simtrace.h"
@@ -221,26 +220,6 @@ void usb_msg_upd_len_and_submit(struct msgb *usb_msg)
usb_buf_submit(usb_msg);
}
/*! Send card change flags over USB
* @param[in] flags change flags corresponding to SIMTRACE_MSGT_SNIFF_CHANGE
*/
static void usb_send_change(uint32_t flags)
{
/* Check flags */
if(0==flags) { /* no changes */
return;
}
/* Send message over USB */
struct msgb *usb_msg = usb_msg_alloc_hdr(SIMTRACE_USB_EP_CARD_DATAIN, SIMTRACE_MSGC_SNIFF, SIMTRACE_MSGT_SNIFF_CHANGE);
if (!usb_msg) {
return;
}
struct sniff_change *usb_sniff_change = (struct sniff_change *) msgb_put(usb_msg, sizeof(*usb_sniff_change));
usb_sniff_change->flags = flags;
usb_msg_upd_len_and_submit(usb_msg);
}
/*! Update the ISO 7816-3 state
* @param[in] iso_state_new new ISO 7816-3 state to update to
*/
@@ -256,11 +235,11 @@ static void change_state(enum iso7816_3_sniff_state iso_state_new)
switch (iso_state_new) {
case ISO7816_S_RESET:
update_fidi(&sniff_usart, 0x11); /* reset baud rate to default Di/Fi values */
usb_send_change(SNIFF_CHANGE_FLAG_RESET_HOLD); /* send reset change to host software over USB */
change_flags |= SNIFF_CHANGE_FLAG_RESET_HOLD; /* set flag and let main loop send it */
break;
case ISO7816_S_WAIT_ATR:
rbuf_reset(&sniff_buffer); /* reset buffer for new communication */
usb_send_change(SNIFF_CHANGE_FLAG_RESET_RELEASE); /* send reset change to host software over USB */
change_flags |= SNIFF_CHANGE_FLAG_RESET_RELEASE; /* set flag and let main loop send it */
break;
case ISO7816_S_IN_ATR:
atr_i = 0;
@@ -705,42 +684,34 @@ static void process_byte_tpdu(uint8_t byte)
void Sniffer_usart_isr(void)
{
/* Read channel status register */
uint32_t csr = sniff_usart.base->US_CSR & sniff_usart.base->US_IMR;
uint32_t csr = sniff_usart.base->US_CSR;
/* Verify if there was an error */
if (csr & US_CSR_OVRE) {
TRACE_WARNING("USART overrun error\n\r");
sniff_usart.base->US_CR |= US_CR_RSTSTA;
}
if (csr & US_CSR_FRAME) {
TRACE_WARNING("USART framing error\n\r");
sniff_usart.base->US_CR |= US_CR_RSTSTA;
}
/* Verify if character has been received */
if (csr & US_CSR_RXRDY) {
/* Read communication data byte between phone and SIM */
uint8_t byte = sniff_usart.base->US_RHR;
/* Convert convention if required */
if (convention_convert) {
byte = convention_convert_lut[byte];
}
/* Store sniffed data into buffer (also clear interrupt */
rbuf_write(&sniff_buffer, byte);
if (rbuf_is_full(&sniff_buffer)) {
TRACE_ERROR("USART buffer full\n\r");
} else {
rbuf_write(&sniff_buffer, byte);
}
}
/* Verify it WT timeout occurred, to detect unresponsive card */
if (csr & US_CSR_TIMEOUT) {
/* Stop timeout until next character is received */
sniff_usart.base->US_CR |= US_CR_STTTO;
/* Use timeout to detect end of ATR/PPS/TPDU */
switch (iso_state) {
case ISO7816_S_RESET:
case ISO7816_S_WAIT_ATR:
break;
case ISO7816_S_IN_ATR:
change_state(ISO7816_S_WAIT_ATR);
break;
case ISO7816_S_WAIT_TPDU:
break;
case ISO7816_S_WAIT_PPS_RSP:
case ISO7816_S_IN_TPDU:
case ISO7816_S_IN_PPS_REQ:
case ISO7816_S_IN_PPS_RSP:
change_state(ISO7816_S_WAIT_TPDU);
break;
default:
break;
}
usb_send_change(SNIFF_CHANGE_FLAG_TIMEOUT_WT); /* send timeout to host software over USB */
/* Just set the flag and let the main loop handle it */
change_flags |= SNIFF_CHANGE_FLAG_TIMEOUT_WT;
}
}
@@ -844,6 +815,30 @@ void Sniffer_init(void)
}
}
/*! Send card change flags over USB
* @param[in] flags change flags corresponding to SIMTRACE_MSGT_SNIFF_CHANGE
*/
static void usb_send_change(uint32_t flags)
{
/* Check flags */
if(0==flags) { /* no changes */
return;
}
if (flags&SNIFF_CHANGE_FLAG_TIMEOUT_WT) {
printf("waiting time (WT) timeout\n\r");
}
/* Send message over USB */
struct msgb *usb_msg = usb_msg_alloc_hdr(SIMTRACE_USB_EP_CARD_DATAIN, SIMTRACE_MSGC_SNIFF, SIMTRACE_MSGT_SNIFF_CHANGE);
if (!usb_msg) {
return;
}
struct sniff_change *usb_sniff_change = (struct sniff_change *) msgb_put(usb_msg, sizeof(*usb_sniff_change));
usb_sniff_change->flags = flags;
usb_msg_upd_len_and_submit(usb_msg);
}
/* Main (idle/busy) loop of this USB configuration */
void Sniffer_run(void)
{
@@ -862,7 +857,11 @@ void Sniffer_run(void)
/* Handle sniffed data */
if (!rbuf_is_empty(&sniff_buffer)) { /* use if instead of while to let the main loop restart the watchdog */
uint8_t byte = rbuf_read(&sniff_buffer);
TRACE_DEBUG_WP("< 0x%02x\n\r", byte);
/* Convert convention if required */
if (convention_convert) {
byte = convention_convert_lut[byte];
}
//TRACE_ERROR_WP(">%02x", byte);
switch (iso_state) { /* Handle byte depending on state */
case ISO7816_S_RESET: /* During reset we shouldn't receive any data */
break;
@@ -899,6 +898,31 @@ void Sniffer_run(void)
/* Handle flags */
if (change_flags) { /* WARNING this is not synced with the data buffer handling */
if (change_flags&SNIFF_CHANGE_FLAG_TIMEOUT_WT) {
/* Use timeout to detect interrupted data transmission */
switch (iso_state) {
case ISO7816_S_IN_ATR:
//usb_send_atr(false); /* send incomplete ATR to host software using USB */
change_state(ISO7816_S_WAIT_ATR);
break;
case ISO7816_S_IN_TPDU:
//usb_send_tpdu(false); /* send incomplete PPS to host software using USB */
change_state(ISO7816_S_WAIT_TPDU);
break;
case ISO7816_S_IN_PPS_REQ:
case ISO7816_S_IN_PPS_RSP:
//usb_send_pps(false); /* send incomplete TPDU to host software using USB */
change_state(ISO7816_S_WAIT_TPDU);
break;
default:
change_flags &= ~SNIFF_CHANGE_FLAG_TIMEOUT_WT; /* We don't care about the timeout is all other cases */
break;
}
}
if (change_flags) {
usb_send_change(change_flags); /* send timeout to host software over USB */
change_flags = 0; /* Reset flags */
}
}
}
#endif /* HAVE_SNIFFER */

View File

@@ -92,7 +92,7 @@ static int gsmtap_send_sim(const uint8_t *apdu, unsigned int len)
return 0;
}
static int process_change(uint8_t *buf, int len)
static int process_change(const uint8_t *buf, int len)
{
/* check if there is enough data for the structure */
if (len<sizeof(struct sniff_change)) {
@@ -100,9 +100,7 @@ static int process_change(uint8_t *buf, int len)
}
struct sniff_change *change = (struct sniff_change *)buf;
if (SNIFF_CHANGE_FLAG_TIMEOUT_WT!=change->flags) {
printf("Card state change: ");
}
printf("Card state change: ");
if (change->flags&SNIFF_CHANGE_FLAG_CARD_INSERT) {
printf("card inserted ");
}
@@ -116,11 +114,9 @@ static int process_change(uint8_t *buf, int len)
printf("reset release ");
}
if (change->flags&SNIFF_CHANGE_FLAG_TIMEOUT_WT) {
// do nothing since this also triggers on inactivity
}
if (SNIFF_CHANGE_FLAG_TIMEOUT_WT!=change->flags) {
printf("\n");
printf("data transfer timeout ");
}
printf("\n");
return 0;
}
@@ -131,7 +127,7 @@ static const uint16_t fi_table[] = { 372, 372, 558, 744, 1116, 1488, 1860, 0, 0,
/* Table 8 from ISO 7816-3:2006 */
static const uint8_t di_table[] = { 0, 1, 2, 4, 8, 16, 32, 64, 12, 20, 2, 4, 8, 16, 32, 64, };
static int process_fidi(uint8_t *buf, int len)
static int process_fidi(const uint8_t *buf, int len)
{
/* check if there is enough data for the structure */
if (len<sizeof(struct sniff_fidi)) {
@@ -143,7 +139,7 @@ static int process_fidi(uint8_t *buf, int len)
return 0;
}
static int process_atr(uint8_t *buf, int len)
static int process_atr(const uint8_t *buf, int len)
{
/* check if there is enough data for the structure */
if (len<sizeof(struct sniff_data)) {
@@ -165,7 +161,7 @@ static int process_atr(uint8_t *buf, int len)
return 0;
}
static int process_pps(uint8_t *buf, int len)
static int process_pps(const uint8_t *buf, int len)
{
/* check if there is enough data for the structure */
if (len<sizeof(struct sniff_data)) {
@@ -187,7 +183,7 @@ static int process_pps(uint8_t *buf, int len)
return 0;
}
static int process_tpdu(uint8_t *buf, int len)
static int process_tpdu(const uint8_t *buf, int len)
{
/* check if there is enough data for the structure */
if (len<sizeof(struct sniff_data)) {
@@ -200,17 +196,21 @@ static int process_tpdu(uint8_t *buf, int len)
return -2;
}
/* print TPDU */
printf("TPDU%s: ", tpdu->complete ? "" : " (incomplete)");
uint16_t i;
for (i = 0; i < tpdu->length; i++) {
printf("%02x ", tpdu->data[i]);
}
printf("\n");
/* send TPDU (now considered as APDU) to GSMTAP */
gsmtap_send_sim(tpdu->data, tpdu->length);
return 0;
}
/*! \brief Process an incoming message from the SIMtrace2 */
static int process_usb_msg(uint8_t *buf, int len)
static int process_usb_msg(const uint8_t *buf, int len)
{
/* check if enough data for the header is present */
if (len<sizeof(struct simtrace_msg_hdr)) {