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sam_common: extract payload copy procedures

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This commit is contained in:
Jakub Kramarz 2025-01-26 14:28:59 +01:00
commit b8d5daa77b
3 changed files with 78 additions and 77 deletions
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73
armsrc/sam_common.c
View file

@ -371,3 +371,76 @@ void sam_send_ack(void) {
BigBuf_free();
}
/**
* @brief Copies the payload from an NFC buffer to a SAM buffer.
*
* Wraps received data from NFC into an ASN1 tree, so it can be transmitted to the SAM .
*
* @param sam_tx Pointer to the SAM transmit buffer.
* @param nfc_rx Pointer to the NFC receive buffer.
* @param nfc_len Length of the data to be copied from the NFC buffer.
*
* @return Length of SAM APDU to be sent.
*/
uint16_t sam_copy_payload_nfc2sam(uint8_t *sam_tx, uint8_t *nfc_rx, uint8_t nfc_len) {
// NFC resp:
// 6f 0c 84 0a a0 00 00 04 40 00 01 01 00 01 90 00 fb e3
// SAM req:
// bd 1c
// a0 1a
// a0 18
// 80 12
// 6f 0c 84 0a a0 00 00 04 40 00 01 01 00 01 90 00 fb e3
// 81 02
// 00 00
const uint8_t payload[] = {
0xbd, 4,
0xa0, 2,
0xa0, 0
};
const uint8_t tag81[] = {
0x00, 0x00
};
memcpy(sam_tx, payload, sizeof(payload));
sam_append_asn1_node(sam_tx, sam_tx + 4, 0x80, nfc_rx, nfc_len);
sam_append_asn1_node(sam_tx, sam_tx + 4, 0x81, tag81, sizeof(tag81));
return sam_tx[1] + 2; // length of the ASN1 tree
}
/**
* @brief Copies the payload from the SAM receive buffer to the NFC transmit buffer.
*
* Unpacks data to be transmitted from ASN1 tree in APDU received from SAM.
*
* @param nfc_tx_buf Pointer to the buffer where the NFC transmit data will be stored.
* @param sam_rx_buf Pointer to the buffer containing the data received from the SAM.
* @return Length of NFC APDU to be sent.
*/
uint16_t sam_copy_payload_sam2nfc(uint8_t *nfc_tx_buf, uint8_t *sam_rx_buf) {
// SAM resp:
// c1 61 c1 00 00
// a1 10 <- nfc command
// a1 0e <- nfc send
// 80 10 <- data
// 00 a4 04 00 0a a0 00 00 04 40 00 01 01 00 01 00
// 81 02 <- protocol
// 00 04
// 82 02 <- timeout
// 01 F4
// 90 00
// NFC req:
// 0C 05 DE 64
// copy data out of c1->a1>->a1->80 node
uint16_t nfc_tx_len = (uint8_t) * (sam_rx_buf + 10);
memcpy(nfc_tx_buf, sam_rx_buf + 11, nfc_tx_len);
return nfc_tx_len;
}

3
armsrc/sam_common.h
View file

@ -46,4 +46,7 @@ void sam_append_asn1_node(const uint8_t *root, const uint8_t *node, uint8_t type
void sam_send_ack(void);
uint16_t sam_copy_payload_nfc2sam(uint8_t *sam_tx, uint8_t *nfc_rx, uint8_t nfc_len);
uint16_t sam_copy_payload_sam2nfc(uint8_t *nfc_tx_buf, uint8_t *sam_rx_buf);
#endif

79
armsrc/sam_seos.c
View file

@ -112,81 +112,6 @@ out:
return res;
}
/**
* @brief Copies the payload from an NFC buffer to a SAM buffer.
*
* Wraps received data from NFC into an ASN1 tree, so it can be transmitted to the SAM .
*
* @param sam_tx Pointer to the SAM transmit buffer.
* @param nfc_rx Pointer to the NFC receive buffer.
* @param nfc_len Length of the data to be copied from the NFC buffer.
*
* @return Length of SAM APDU to be sent.
*/
inline static uint16_t sam_seos_copy_payload_nfc2sam(uint8_t *sam_tx, uint8_t *nfc_rx, uint8_t nfc_len) {
// NFC resp:
// 6f 0c 84 0a a0 00 00 04 40 00 01 01 00 01 90 00 fb e3
// SAM req:
// bd 1c
// a0 1a
// a0 18
// 80 12
// 6f 0c 84 0a a0 00 00 04 40 00 01 01 00 01 90 00 fb e3
// 81 02
// 00 00
const uint8_t payload[] = {
0xbd, 4,
0xa0, 2,
0xa0, 0
};
const uint8_t tag81[] = {
0x00, 0x00
};
memcpy(sam_tx, payload, sizeof(payload));
sam_append_asn1_node(sam_tx, sam_tx + 4, 0x80, nfc_rx, nfc_len);
sam_append_asn1_node(sam_tx, sam_tx + 4, 0x81, tag81, sizeof(tag81));
return sam_tx[1] + 2; // length of the ASN1 tree
}
/**
* @brief Copies the payload from the SAM receive buffer to the NFC transmit buffer.
*
* Unpacks data to be transmitted from ASN1 tree in APDU received from SAM.
*
* @param nfc_tx_buf Pointer to the buffer where the NFC transmit data will be stored.
* @param sam_rx_buf Pointer to the buffer containing the data received from the SAM.
* @return Length of NFC APDU to be sent.
*/
inline static uint16_t sam_seos_copy_payload_sam2nfc(uint8_t *nfc_tx_buf, uint8_t *sam_rx_buf) {
// SAM resp:
// c1 61 c1 00 00
// a1 21 <- nfc command
// a1 1f <- nfc send
// 80 10 <- data
// 00 a4 04 00 0a a0 00 00 04 40 00 01 01 00 01 00
// 81 02 <- protocol
// 02 02
// 82 02 <- timeout
// 01 2e
// 85 03 <- format
// 06 c0 00
// 90 00
// NFC req:
// 00 a4 04 00 0a a0 00 00 04 40 00 01 01 00 01 00
// copy data out of c1->a1>->a1->80 node
uint16_t nfc_tx_len = (uint8_t) * (sam_rx_buf + 10);
memcpy(nfc_tx_buf, sam_rx_buf + 11, nfc_tx_len);
return nfc_tx_len;
}
/**
* @brief Sends a request to the SAM and retrieves the response.
*
@ -247,7 +172,7 @@ static int sam_send_request_iso14a(const uint8_t *const request, const uint8_t r
// tag <-> SAM exchange starts here
while (sam_rx_buf[1] == 0x61) {
switch_clock_to_countsspclk();
nfc_tx_len = sam_seos_copy_payload_sam2nfc(nfc_tx_buf, sam_rx_buf);
nfc_tx_len = sam_copy_payload_sam2nfc(nfc_tx_buf, sam_rx_buf);
nfc_rx_len = iso14_apdu(
nfc_tx_buf,
@ -259,7 +184,7 @@ static int sam_send_request_iso14a(const uint8_t *const request, const uint8_t r
);
switch_clock_to_ticks();
sam_tx_len = sam_seos_copy_payload_nfc2sam(sam_tx_buf, nfc_rx_buf, nfc_rx_len - 2);
sam_tx_len = sam_copy_payload_nfc2sam(sam_tx_buf, nfc_rx_buf, nfc_rx_len - 2);
sam_send_payload(
0x14, 0x0a, 0x14,