sam_common: extract payload copy procedures

armsrc/sam_common.c

@@ -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;
+}