//-----------------------------------------------------------------------------
// Copyright (C) 2012 Frederik Möllers
//
// 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.
//-----------------------------------------------------------------------------
// Commands related to the German electronic Identification Card
//-----------------------------------------------------------------------------
#include "cmdhfepa.h"

static int CmdHelp(const char *Cmd);

// Perform (part of) the PACE protocol
int CmdHFEPACollectPACENonces(const char *Cmd)
{
	// requested nonce size
	uint32_t m = 0;
	// requested number of Nonces
	uint32_t n = 0;
	// delay between requests
	uint32_t d = 0;

	sscanf(Cmd, "%u %u %u", &m, &n, &d);

	// values are expected to be > 0
	m = m > 0 ? m : 1;
	n = n > 0 ? n : 1;

	PrintAndLogEx(NORMAL, "Collecting %u %u byte nonces", n, m);
	PrintAndLogEx(NORMAL, "Start: %" PRIu64, msclock()/1000);
	// repeat n times
	for (uint32_t i = 0; i < n; i++) {
		// execute PACE
		UsbCommand c = {CMD_EPA_PACE_COLLECT_NONCE, {(int)m, 0, 0}};
		clearCommandBuffer();
		SendCommand(&c);
		UsbCommand resp;
		WaitForResponse(CMD_ACK,&resp);

		// check if command failed
		if (resp.arg[0] != 0) {
			PrintAndLogEx(FAILED, "Error in step %d, Return code: %d",resp.arg[0],(int)resp.arg[1]);
		} else {
			size_t nonce_length = resp.arg[1];
			char *nonce = (char *) calloc(2 * nonce_length + 1, sizeof(uint8_t));
			for(int j = 0; j < nonce_length; j++) {
				sprintf(nonce + (2 * j), "%02X", resp.d.asBytes[j]);
			}
			// print nonce
			PrintAndLogEx(NORMAL, "Length: %d, Nonce: %s", nonce_length, nonce);
			free(nonce);
		}
		if (i < n - 1) {
			sleep(d);
		}
	}
	PrintAndLogEx(NORMAL, "End: %" PRIu64, msclock()/1000);
	return 1;
}

// perform the PACE protocol by replaying APDUs
int CmdHFEPAPACEReplay(const char *Cmd)
{
	// the 4 APDUs which are replayed + their lengths
	uint8_t msesa_apdu[41], gn_apdu[8], map_apdu[75];
	uint8_t pka_apdu[75], ma_apdu[18], apdu_lengths[5] = {0};
	// pointers to the arrays to be able to iterate
	uint8_t *apdus[] = {msesa_apdu, gn_apdu, map_apdu, pka_apdu, ma_apdu};

	// usage message
	static const char *usage_msg =
		"Please specify 5 APDUs separated by spaces. "
		"Example:\n preplay 0022C1A4 1068000000 1086000002 1234ABCDEF 1A2B3C4D";

	// Proxmark response
	UsbCommand resp;

	int skip = 0, skip_add = 0, scan_return = 0;
	// for each APDU
	for (int i = 0; i < sizeof(apdu_lengths); i++) {
		// scan to next space or end of string
		while (Cmd[skip] != ' ' && Cmd[skip] != '\0') {
			// convert
			scan_return = sscanf(Cmd + skip, "%2X%n",
			                     (unsigned int *) (apdus[i] + apdu_lengths[i]),
			                     &skip_add);
			if (scan_return < 1) {
				PrintAndLogEx(NORMAL, (char *)usage_msg);
				PrintAndLogEx(WARNING, "Not enough APDUs! Try again!");
				return 0;
			}
			skip += skip_add;
            apdu_lengths[i]++;
		}

		// break on EOF
		if (Cmd[skip] == '\0') {
			if (i < sizeof(apdu_lengths) - 1) {

				PrintAndLogEx(NORMAL, (char *)usage_msg);
				return 0;
			}
			break;
		}
		// skip the space
		skip++;
	}

	// transfer the APDUs to the Proxmark
	UsbCommand usb_cmd;
	usb_cmd.cmd = CMD_EPA_PACE_REPLAY;
	for (int i = 0; i < sizeof(apdu_lengths); i++) {
		// APDU number
		usb_cmd.arg[0] = i + 1;
		// transfer the APDU in several parts if necessary
		for (int j = 0; j * sizeof(usb_cmd.d.asBytes) < apdu_lengths[i]; j++) {
			// offset into the APDU
			usb_cmd.arg[1] = j * sizeof(usb_cmd.d.asBytes);
			// amount of data in this packet
			int packet_length = apdu_lengths[i] - (j * sizeof(usb_cmd.d.asBytes));
			if (packet_length > sizeof(usb_cmd.d.asBytes)) {
				packet_length = sizeof(usb_cmd.d.asBytes);
			}
			usb_cmd.arg[2] = packet_length;

			memcpy(usb_cmd.d.asBytes, // + (j * sizeof(usb_cmd.d.asBytes)),
			       apdus[i] + (j * sizeof(usb_cmd.d.asBytes)),
			       packet_length);
				   
			clearCommandBuffer();				   
			SendCommand(&usb_cmd);
			WaitForResponse(CMD_ACK, &resp);
			if (resp.arg[0] != 0) {
				PrintAndLogEx(WARNING, "Transfer of APDU #%d Part %d failed!", i, j);
				return 0;
			}
		}
	}

	// now perform the replay
	usb_cmd.arg[0] = 0;
	clearCommandBuffer();
	SendCommand(&usb_cmd);
	WaitForResponse(CMD_ACK, &resp);
	if (resp.arg[0] != 0) {
		PrintAndLogEx(NORMAL, "\nPACE replay failed in step %u!", (uint32_t)resp.arg[0]);
		PrintAndLogEx(NORMAL, "Measured times:");
		PrintAndLogEx(NORMAL, "MSE Set AT: %u us", resp.d.asDwords[0]);
		PrintAndLogEx(NORMAL, "GA Get Nonce: %u us", resp.d.asDwords[1]);
		PrintAndLogEx(NORMAL, "GA Map Nonce: %u us", resp.d.asDwords[2]);
		PrintAndLogEx(NORMAL, "GA Perform Key Agreement: %u us", resp.d.asDwords[3]);
		PrintAndLogEx(NORMAL, "GA Mutual Authenticate: %u us", resp.d.asDwords[4]);
	} else {
		PrintAndLogEx(NORMAL, "PACE replay successfull!");
		PrintAndLogEx(NORMAL, "MSE Set AT: %u us", resp.d.asDwords[0]);
		PrintAndLogEx(NORMAL, "GA Get Nonce: %u us", resp.d.asDwords[1]);
		PrintAndLogEx(NORMAL, "GA Map Nonce: %u us", resp.d.asDwords[2]);
		PrintAndLogEx(NORMAL, "GA Perform Key Agreement: %u us", resp.d.asDwords[3]);
		PrintAndLogEx(NORMAL, "GA Mutual Authenticate: %u us", resp.d.asDwords[4]);
	}
	return 1;
}

static command_t CommandTable[] = {
	{"help",    CmdHelp,                   1, "This help"},
	{"cnonces", CmdHFEPACollectPACENonces, 0, "<m> <n> <d> Acquire n>0 encrypted PACE nonces of size m>0 with d sec pauses"},
	{"preplay", CmdHFEPAPACEReplay,        0, "<mse> <get> <map> <pka> <ma> Perform PACE protocol by replaying given APDUs"},
 	{NULL, NULL, 0, NULL}
};

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

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