[proxmark3-svn] / client / cmdcrc.c

//-----------------------------------------------------------------------------
// Copyright (C) 2015 iceman <iceman at iuse.se>
//
// 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.
//-----------------------------------------------------------------------------
// CRC Calculations from the software reveng commands
//-----------------------------------------------------------------------------

#include <stdlib.h>
#ifdef _WIN32
#  include <io.h>
#  include <fcntl.h>
#  ifndef STDIN_FILENO
#    define STDIN_FILENO 0
#  endif /* STDIN_FILENO */
#endif /* _WIN32 */

#include <stdio.h>
#include <string.h>
//#include <stdlib.h>
//#include <ctype.h>
#include "cmdmain.h"
#include "cmdcrc.h"
#include "reveng/reveng.h"
#include "ui.h"
#include "util.h"

#define MAX_ARGS 20

int uerr(char *msg){
	PrintAndLog("%s",msg);
	return 0;
}

int split(char *str, char *arr[MAX_ARGS]){
    int beginIndex = 0;
    int endIndex;
    int maxWords = MAX_ARGS;
    int wordCnt = 0;

    while(1){
        while(isspace(str[beginIndex])){
            ++beginIndex;
        }
        if(str[beginIndex] == '\0')
            break;
        endIndex = beginIndex;
        while (str[endIndex] && !isspace(str[endIndex])){
            ++endIndex;
        }
        int len = endIndex - beginIndex;
        char *tmp = calloc(len + 1, sizeof(char));
        memcpy(tmp, &str[beginIndex], len);
        arr[wordCnt++] = tmp;
        //PrintAndLog("cnt: %d, %s",wordCnt-1, arr[wordCnt-1]);
        beginIndex = endIndex;
        if (wordCnt == maxWords)
            break;
    }
    return wordCnt;
}

int CmdCrc(const char *Cmd)
{
	char name[] = {"reveng "};
	char Cmd2[50 + 7];
	memcpy(Cmd2, name, 7);
	memcpy(Cmd2 + 7, Cmd, 50);
	char *argv[MAX_ARGS];
	int argc = split(Cmd2, argv);

	if (argc == 3 && memcmp(argv[1],"-g",2)==0) {
		CmdrevengSearch(argv[2]);
	} else {
	reveng_main(argc, argv);
	}
	//PrintAndLog("DEBUG argc: %d, %s %s Cmd: %s",argc, argv[0], Cmd2, Cmd);
	for(int i = 0; i < argc; ++i){
		free(argv[i]);
	}

  return 0; 
}

//returns array of model names and the count of models returning
//  as well as a width array for the width of each model
int GetModels(char *Models[], int *count, uint8_t *width){
	/* default values */
	static model_t model = {
		PZERO,		/* no CRC polynomial, user must specify */
		PZERO,		/* Init = 0 */
		P_BE,		/* RefIn = false, RefOut = false, plus P_RTJUST setting in reveng.h */
		PZERO,		/* XorOut = 0 */
		PZERO,		/* check value unused */
		NULL		/* no model name */
	};

	int ibperhx = 8;//, obperhx = 8;
	int rflags = 0, uflags = 0; /* search and UI flags */
	poly_t apoly, crc, qpoly = PZERO, *apolys = NULL, *pptr = NULL, *qptr = NULL;
	model_t pset = model, *candmods, *mptr;

	/* stdin must be binary */
	#ifdef _WIN32
		_setmode(STDIN_FILENO, _O_BINARY);
	#endif /* _WIN32 */

	SETBMP();
	
	int args = 0, psets, pass;
	int Cnt = 0;
	if (width[0] == 0) { //reveng -D
		*count = mcount();
		if(!*count)
			return uerr("no preset models available");

		for(int mode = 0; mode < *count; ++mode) {
			mbynum(&model, mode);
			mcanon(&model);
			size_t size = (model.name && *model.name) ? strlen(model.name) : 6;
			char *tmp = calloc(size+1, sizeof(char));
			if (tmp==NULL)
				return uerr("out of memory?");

			memcpy(tmp, model.name, size);
			Models[mode] = tmp;
			width[mode] = plen(model.spoly);
		}
		mfree(&model);
	} else { //reveng -s

			if(~model.flags & P_MULXN)
				return uerr("cannot search for non-Williams compliant models");

		praloc(&model.spoly, (unsigned long)width[0]);
		praloc(&model.init, (unsigned long)width[0]);
		praloc(&model.xorout, (unsigned long)width[0]);
			if(!plen(model.spoly))
			palloc(&model.spoly, (unsigned long)width[0]);
			else
			width[0] = (uint8_t)plen(model.spoly);

			/* special case if qpoly is zero, search to end of range */
			if(!ptst(qpoly))
				rflags &= ~R_HAVEQ;

			/* if endianness not specified, try
			 * little-endian then big-endian.
			 * NB: crossed-endian algorithms will not be
			 * searched.
			 */
			/* scan against preset models */
			if(~uflags & C_FORCE) {
				pass = 0;
				Cnt = 0;
				do {
					psets = mcount();

					while(psets) {
						mbynum(&pset, --psets);
						
						/* skip if different width, or refin or refout don't match */
					if(plen(pset.spoly) != width[0] || (model.flags ^ pset.flags) & (P_REFIN | P_REFOUT))
							continue;
						/* skip if the preset doesn't match specified parameters */
						if(rflags & R_HAVEP && pcmp(&model.spoly, &pset.spoly))
							continue;
						if(rflags & R_HAVEI && psncmp(&model.init, &pset.init))
							continue;
						if(rflags & R_HAVEX && psncmp(&model.xorout, &pset.xorout))
							continue;
				
					//for additional args (not used yet, maybe future?)
						apoly = pclone(pset.xorout);
						if(pset.flags & P_REFOUT)
							prev(&apoly);
					
						for(qptr = apolys; qptr < pptr; ++qptr) {
							crc = pcrc(*qptr, pset.spoly, pset.init, apoly, 0);
							if(ptst(crc)) {
								pfree(&crc);
								break;
							} else
								pfree(&crc);
						}
						pfree(&apoly);
						if(qptr == pptr) {

							/* the selected model solved all arguments */

							mcanon(&pset);
							
							size_t size = (pset.name && *pset.name) ? strlen(pset.name) : 6;
							//PrintAndLog("Size: %d, %s, count: %d",size,pset.name, Cnt);
							char *tmp = calloc(size+1, sizeof(char));
							if (tmp == NULL){
								PrintAndLog("out of memory?");
								return 0;
							}
						width[Cnt] = width[0];
							memcpy(tmp, pset.name, size);
							Models[Cnt++] = tmp;
							*count = Cnt;
							uflags |= C_RESULT;
						}
					}
					mfree(&pset);

					/* toggle refIn/refOut and reflect arguments */
					if(~rflags & R_HAVERI) {
						model.flags ^= P_REFIN | P_REFOUT;
						for(qptr = apolys; qptr < pptr; ++qptr)
							prevch(qptr, ibperhx);
					}
				} while(~rflags & R_HAVERI && ++pass < 2);
			}
		//got everything now free the memory...

			if(uflags & C_RESULT) {
				for(qptr = apolys; qptr < pptr; ++qptr)
					pfree(qptr);
			}
			if(!(model.flags & P_REFIN) != !(model.flags & P_REFOUT))
				return uerr("cannot search for crossed-endian models");

			pass = 0;
			do {
				mptr = candmods = reveng(&model, qpoly, rflags, args, apolys);
				if(mptr && plen(mptr->spoly))
					uflags |= C_RESULT;
				while(mptr && plen(mptr->spoly)) {
					mfree(mptr++);
				}
				free(candmods);
				if(~rflags & R_HAVERI) {
					model.flags ^= P_REFIN | P_REFOUT;
					for(qptr = apolys; qptr < pptr; ++qptr)
						prevch(qptr, ibperhx);
				}
			} while(~rflags & R_HAVERI && ++pass < 2);
			for(qptr = apolys; qptr < pptr; ++qptr)
				pfree(qptr);
			free(apolys);
			if(~uflags & C_RESULT)
				return uerr("no models found");
			mfree(&model);

	}
	return 1;
}

//-c || -v
//inModel = valid model name string - CRC-8
//inHexStr = input hex string to calculate crc on
//reverse = reverse calc option if true
//endian = {0 = calc default endian input and output, b = big endian input and output, B = big endian output, r = right justified
//          l = little endian input and output, L = little endian output only, t = left justified}
//result = calculated crc hex string
int RunModel(char *inModel, char *inHexStr, bool reverse, char endian, char *result){
	/* default values */
	static model_t model = {
		PZERO,		// no CRC polynomial, user must specify
		PZERO,		// Init = 0
		P_BE,		  // RefIn = false, RefOut = false, plus P_RTJUST setting in reveng.h
		PZERO,		// XorOut = 0
		PZERO,		// check value unused 
		NULL		  // no model name 
	};
	int ibperhx = 8, obperhx = 8;
	int rflags = 0; // search flags 
	int c;
	poly_t apoly, crc;

	char *string;

	// stdin must be binary
	#ifdef _WIN32
		_setmode(STDIN_FILENO, _O_BINARY);
	#endif /* _WIN32 */

	SETBMP();
	//set model
	if(!(c = mbynam(&model, inModel))) {
		PrintAndLog("error: preset model '%s' not found.  Use reveng -D to list presets.", inModel);
		return 0;
	}
	if(c < 0)
		return uerr("no preset models available");

	rflags |= R_HAVEP | R_HAVEI | R_HAVERI | R_HAVERO | R_HAVEX;
	
	//set flags
	switch (endian) {
		case 'b': /* b  big-endian (RefIn = false, RefOut = false ) */
			model.flags &= ~P_REFIN;
			rflags |= R_HAVERI;
			/* fall through: */
		case 'B': /* B  big-endian output (RefOut = false) */
			model.flags &= ~P_REFOUT;
			rflags |= R_HAVERO;
			mnovel(&model);
			/* fall through: */
		case 'r': /* r  right-justified */
			model.flags |= P_RTJUST;
			break;
		case 'l': /* l  little-endian input and output */
			model.flags |= P_REFIN;
			rflags |= R_HAVERI;
			/* fall through: */
		case 'L': /* L  little-endian output */
			model.flags |= P_REFOUT;
			rflags |= R_HAVERO;
			mnovel(&model);
			/* fall through: */
		case 't': /* t  left-justified */
			model.flags &= ~P_RTJUST;
			break;
	}

	mcanon(&model);

	if (reverse) {
		// v  calculate reversed CRC
		/* Distinct from the -V switch as this causes
		 * the arguments and output to be reversed as well.
		 */
		// reciprocate Poly
		prcp(&model.spoly);

		/* mrev() does:
		 *   if(refout) prev(init); else prev(xorout);
		 * but here the entire argument polynomial is
		 * reflected, not just the characters, so RefIn
		 * and RefOut are not inverted as with -V.
		 * Consequently Init is the mirror image of the
		 * one resulting from -V, and so we have:
		 */
		if(~model.flags & P_REFOUT) {
			prev(&model.init);
			prev(&model.xorout);
		}

		// swap init and xorout
		apoly = model.init;
		model.init = model.xorout;
		model.xorout = apoly;
	}
	// c  calculate CRC

	/* in the Williams model, xorout is applied after the refout stage.
	 * as refout is part of ptostr(), we reverse xorout here.
	 */
	if(model.flags & P_REFOUT)
		prev(&model.xorout);

	apoly = strtop(inHexStr, model.flags, ibperhx);

	if(reverse)
		prev(&apoly);

	crc = pcrc(apoly, model.spoly, model.init, model.xorout, model.flags);

	if(reverse)
		prev(&crc);

	string = ptostr(crc, model.flags, obperhx);
	for (int i = 0; i < 50; i++){
		result[i] = string[i];
		if (result[i]==0) break;
	}
	free(string);
	pfree(&crc);
	pfree(&apoly);
	return 1;
}
//returns a calloced string (needs to be freed)
char *SwapEndianStr(const char *inStr, const size_t len, const uint8_t blockSize){
	char *tmp = calloc(len+1, sizeof(char));
	for (uint8_t block=0; block < (uint8_t)(len/blockSize); block++){
		for (size_t i = 0; i < blockSize; i+=2){
			tmp[i+(blockSize*block)] = inStr[(blockSize-1-i-1)+(blockSize*block)];
			tmp[i+(blockSize*block)+1] = inStr[(blockSize-1-i)+(blockSize*block)];
		}
	}
	return tmp;
}

// takes hex string in and searches for a matching result (hex string must include checksum)
int CmdrevengSearch(const char *Cmd){
	char inHexStr[50] = {0x00};
	int dataLen = param_getstr(Cmd, 0, inHexStr);
	if (dataLen < 4) return 0;

	char *Models[80];
	int count = 0;
	uint8_t width[80];
	width[0] = 0;
	uint8_t crcChars = 0;
	char result[30];
	char revResult[30];
	int ans = GetModels(Models, &count, width);
	bool found = false;
	if (!ans) return 0;
	
	// try each model and get result
	for (int i = 0; i < count; i++){
		/*if (found) {
			free(Models[i]);
			continue;
		}*/
		// round up to # of characters in this model's crc
		crcChars = ((width[i]+7)/8)*2; 
		// can't test a model that has more crc digits than our data
		if (crcChars >= dataLen) 
			continue;
		memset(result, 0, 30);
		char *inCRC = calloc(crcChars+1, sizeof(char));
		memcpy(inCRC, inHexStr+(dataLen-crcChars), crcChars);

		char *outHex = calloc(dataLen-crcChars+1, sizeof(char));
		memcpy(outHex, inHexStr, dataLen-crcChars);

		//PrintAndLog("DEBUG: dataLen: %d, crcChars: %d, Model: %s, CRC: %s, width: %d, outHex: %s",dataLen, crcChars, Models[i], inCRC, width[i], outHex);
		ans = RunModel(Models[i], outHex, false, 0, result);
		if (ans) {
			//test for match
			if (memcmp(result, inCRC, crcChars)==0){
				PrintAndLog("\nFound a possible match!\nModel: %s\nValue: %s\n",Models[i], result);
				//optional - stop searching if found...
				found = true;
			} else {
				if (crcChars > 2){
					char *swapEndian = SwapEndianStr(result, crcChars, crcChars);
					if (memcmp(swapEndian, inCRC, crcChars)==0){
						PrintAndLog("\nFound a possible match!\nModel: %s\nValue EndianSwapped: %s\n",Models[i], swapEndian);
						//optional - stop searching if found...
						found = true;
					}
					free(swapEndian);
				}
			}
		}
		
		//if (!found){
			ans = RunModel(Models[i], outHex, true, 0, revResult);
			if (ans) {
				//test for match
				if (memcmp(revResult, inCRC, crcChars)==0){
					PrintAndLog("\nFound a possible match!\nModel Reversed: %s\nValue: %s\n",Models[i], revResult);
					//optional - stop searching if found...
					found = true;
				} else {
					if (crcChars > 2){
						char *swapEndian = SwapEndianStr(revResult, crcChars, crcChars);
						if (memcmp(swapEndian, inCRC, crcChars)==0){
							PrintAndLog("\nFound a possible match!\nModel Reversed: %s\nValue EndianSwapped: %s\n",Models[i], swapEndian);
							//optional - stop searching if found...
							found = true;
						}
						free(swapEndian);
					}
				}
			}
		//}
		free(inCRC);
		free(outHex);
		free(Models[i]);
	}
	if (!found) PrintAndLog("\nNo matches found\n");
	return 1;
}
Commit	Line	Data
9962091e	1	//-----------------------------------------------------------------------------
	2	// Copyright (C) 2015 iceman <iceman at iuse.se>
	3	//
	4	// This code is licensed to you under the terms of the GNU GPL, version 2 or,
	5	// at your option, any later version. See the LICENSE.txt file for the text of
	6	// the license.
	7	//-----------------------------------------------------------------------------
	8	// CRC Calculations from the software reveng commands
	9	//-----------------------------------------------------------------------------
	10
60e86577	11	#include <stdlib.h>
	12	#ifdef _WIN32
	13	# include <io.h>
	14	# include <fcntl.h>
	15	# ifndef STDIN_FILENO
	16	# define STDIN_FILENO 0
	17	# endif /* STDIN_FILENO */
	18	#endif /* _WIN32 */
	19
9962091e	20	#include <stdio.h>
9962091e	21	#include <string.h>
a71ece51	22	//#include <stdlib.h>
	23	//#include <ctype.h>
	24	#include "cmdmain.h"
9962091e	25	#include "cmdcrc.h"
a71ece51	26	#include "reveng/reveng.h"
	27	#include "ui.h"
	28	#include "util.h"
9962091e	29
a71ece51	30	#define MAX_ARGS 20
9962091e	31
60e86577	32	int uerr(char *msg){
	33	PrintAndLog("%s",msg);
	34	return 0;
	35	}
	36
a71ece51	37	int split(char str, char arr[MAX_ARGS]){
	38	int beginIndex = 0;
	39	int endIndex;
	40	int maxWords = MAX_ARGS;
	41	int wordCnt = 0;
	42
	43	while(1){
	44	while(isspace(str[beginIndex])){
	45	++beginIndex;
	46	}
	47	if(str[beginIndex] == '\0')
	48	break;
	49	endIndex = beginIndex;
	50	while (str[endIndex] && !isspace(str[endIndex])){
	51	++endIndex;
	52	}
	53	int len = endIndex - beginIndex;
	54	char *tmp = calloc(len + 1, sizeof(char));
	55	memcpy(tmp, &str[beginIndex], len);
	56	arr[wordCnt++] = tmp;
	57	//PrintAndLog("cnt: %d, %s",wordCnt-1, arr[wordCnt-1]);
	58	beginIndex = endIndex;
	59	if (wordCnt == maxWords)
	60	break;
	61	}
	62	return wordCnt;
	63	}
9962091e	64
	65	int CmdCrc(const char *Cmd)
	66	{
a71ece51	67	char name[] = {"reveng "};
	68	char Cmd2[50 + 7];
	69	memcpy(Cmd2, name, 7);
	70	memcpy(Cmd2 + 7, Cmd, 50);
	71	char *argv[MAX_ARGS];
	72	int argc = split(Cmd2, argv);
99789601	73
	74	if (argc == 3 && memcmp(argv[1],"-g",2)==0) {
	75	CmdrevengSearch(argv[2]);
	76	} else {
a71ece51	77	reveng_main(argc, argv);
99789601	78	}
99789601	79	//PrintAndLog("DEBUG argc: %d, %s %s Cmd: %s",argc, argv[0], Cmd2, Cmd);
a71ece51	80	for(int i = 0; i < argc; ++i){
a71ece51	81	free(argv[i]);
	82	}
	83
9962091e	84	return 0;
	85	}
	86
99789601	87	//returns array of model names and the count of models returning
	88	// as well as a width array for the width of each model
	89	int GetModels(char Models[], int count, uint8_t *width){
60e86577	90	/* default values */
	91	static model_t model = {
	92	PZERO, /* no CRC polynomial, user must specify */
	93	PZERO, /* Init = 0 */
	94	P_BE, /* RefIn = false, RefOut = false, plus P_RTJUST setting in reveng.h */
	95	PZERO, /* XorOut = 0 */
	96	PZERO, /* check value unused */
	97	NULL /* no model name */
	98	};
dd1df490	99
60e86577	100	int ibperhx = 8;//, obperhx = 8;
60e86577	101	int rflags = 0, uflags = 0; /* search and UI flags */
60e86577	102	poly_t apoly, crc, qpoly = PZERO, apolys = NULL, pptr = NULL, *qptr = NULL;
	103	model_t pset = model, candmods, mptr;
	104
	105	/* stdin must be binary */
	106	#ifdef _WIN32
	107	_setmode(STDIN_FILENO, _O_BINARY);
	108	#endif /* _WIN32 */
	109
	110	SETBMP();
	111
	112	int args = 0, psets, pass;
	113	int Cnt = 0;
99789601	114	if (width[0] == 0) { //reveng -D
60e86577	115	*count = mcount();
60e86577	116	if(!*count)
	117	return uerr("no preset models available");
	118
	119	for(int mode = 0; mode < *count; ++mode) {
	120	mbynum(&model, mode);
	121	mcanon(&model);
	122	size_t size = (model.name && *model.name) ? strlen(model.name) : 6;
60e86577	123	char *tmp = calloc(size+1, sizeof(char));
	124	if (tmp==NULL)
	125	return uerr("out of memory?");
	126
	127	memcpy(tmp, model.name, size);
	128	Models[mode] = tmp;
99789601	129	width[mode] = plen(model.spoly);
60e86577	130	}
dd1df490	131	mfree(&model);
60e86577	132	} else { //reveng -s
	133
	134	if(~model.flags & P_MULXN)
	135	return uerr("cannot search for non-Williams compliant models");
	136
99789601	137	praloc(&model.spoly, (unsigned long)width[0]);
	138	praloc(&model.init, (unsigned long)width[0]);
	139	praloc(&model.xorout, (unsigned long)width[0]);
60e86577	140	if(!plen(model.spoly))
99789601	141	palloc(&model.spoly, (unsigned long)width[0]);
60e86577	142	else
99789601	143	width[0] = (uint8_t)plen(model.spoly);
60e86577	144
	145	/* special case if qpoly is zero, search to end of range */
	146	if(!ptst(qpoly))
	147	rflags &= ~R_HAVEQ;
	148
	149	/* if endianness not specified, try
	150	* little-endian then big-endian.
	151	* NB: crossed-endian algorithms will not be
	152	* searched.
	153	*/
	154	/* scan against preset models */
	155	if(~uflags & C_FORCE) {
	156	pass = 0;
	157	Cnt = 0;
	158	do {
	159	psets = mcount();
	160
	161	while(psets) {
	162	mbynum(&pset, --psets);
	163
	164	/* skip if different width, or refin or refout don't match */
99789601	165	if(plen(pset.spoly) != width[0] \|\| (model.flags ^ pset.flags) & (P_REFIN \| P_REFOUT))
60e86577	166	continue;
	167	/* skip if the preset doesn't match specified parameters */
	168	if(rflags & R_HAVEP && pcmp(&model.spoly, &pset.spoly))
	169	continue;
	170	if(rflags & R_HAVEI && psncmp(&model.init, &pset.init))
	171	continue;
	172	if(rflags & R_HAVEX && psncmp(&model.xorout, &pset.xorout))
	173	continue;
	174
99789601	175	//for additional args (not used yet, maybe future?)
60e86577	176	apoly = pclone(pset.xorout);
	177	if(pset.flags & P_REFOUT)
	178	prev(&apoly);
99789601	179
60e86577	180	for(qptr = apolys; qptr < pptr; ++qptr) {
	181	crc = pcrc(*qptr, pset.spoly, pset.init, apoly, 0);
	182	if(ptst(crc)) {
	183	pfree(&crc);
	184	break;
	185	} else
	186	pfree(&crc);
	187	}
	188	pfree(&apoly);
	189	if(qptr == pptr) {
99789601	190
60e86577	191	/* the selected model solved all arguments */
99789601	192
60e86577	193	mcanon(&pset);
	194
	195	size_t size = (pset.name && *pset.name) ? strlen(pset.name) : 6;
	196	//PrintAndLog("Size: %d, %s, count: %d",size,pset.name, Cnt);
	197	char *tmp = calloc(size+1, sizeof(char));
60e86577	198	if (tmp == NULL){
	199	PrintAndLog("out of memory?");
	200	return 0;
	201	}
99789601	202	width[Cnt] = width[0];
60e86577	203	memcpy(tmp, pset.name, size);
	204	Models[Cnt++] = tmp;
	205	*count = Cnt;
	206	uflags \|= C_RESULT;
	207	}
	208	}
	209	mfree(&pset);
	210
	211	/* toggle refIn/refOut and reflect arguments */
	212	if(~rflags & R_HAVERI) {
	213	model.flags ^= P_REFIN \| P_REFOUT;
	214	for(qptr = apolys; qptr < pptr; ++qptr)
	215	prevch(qptr, ibperhx);
	216	}
	217	} while(~rflags & R_HAVERI && ++pass < 2);
	218	}
99789601	219	//got everything now free the memory...
99789601	220
60e86577	221	if(uflags & C_RESULT) {
	222	for(qptr = apolys; qptr < pptr; ++qptr)
	223	pfree(qptr);
60e86577	224	}
	225	if(!(model.flags & P_REFIN) != !(model.flags & P_REFOUT))
	226	return uerr("cannot search for crossed-endian models");
dd1df490	227
60e86577	228	pass = 0;
	229	do {
	230	mptr = candmods = reveng(&model, qpoly, rflags, args, apolys);
	231	if(mptr && plen(mptr->spoly))
	232	uflags \|= C_RESULT;
	233	while(mptr && plen(mptr->spoly)) {
60e86577	234	mfree(mptr++);
	235	}
	236	free(candmods);
	237	if(~rflags & R_HAVERI) {
	238	model.flags ^= P_REFIN \| P_REFOUT;
	239	for(qptr = apolys; qptr < pptr; ++qptr)
	240	prevch(qptr, ibperhx);
	241	}
	242	} while(~rflags & R_HAVERI && ++pass < 2);
	243	for(qptr = apolys; qptr < pptr; ++qptr)
	244	pfree(qptr);
	245	free(apolys);
	246	if(~uflags & C_RESULT)
	247	return uerr("no models found");
dd1df490	248	mfree(&model);
60e86577	249
60e86577	250	}
	251	return 1;
	252	}
	253
	254	//-c \|\| -v
	255	//inModel = valid model name string - CRC-8
	256	//inHexStr = input hex string to calculate crc on
	257	//reverse = reverse calc option if true
	258	//endian = {0 = calc default endian input and output, b = big endian input and output, B = big endian output, r = right justified
	259	// l = little endian input and output, L = little endian output only, t = left justified}
	260	//result = calculated crc hex string
	261	int RunModel(char inModel, char inHexStr, bool reverse, char endian, char *result){
	262	/* default values */
	263	static model_t model = {
	264	PZERO, // no CRC polynomial, user must specify
	265	PZERO, // Init = 0
	266	P_BE, // RefIn = false, RefOut = false, plus P_RTJUST setting in reveng.h
	267	PZERO, // XorOut = 0
	268	PZERO, // check value unused
	269	NULL // no model name
	270	};
	271	int ibperhx = 8, obperhx = 8;
	272	int rflags = 0; // search flags
	273	int c;
60e86577	274	poly_t apoly, crc;
	275
	276	char *string;
	277
	278	// stdin must be binary
	279	#ifdef _WIN32
	280	_setmode(STDIN_FILENO, _O_BINARY);
	281	#endif /* _WIN32 */
	282
	283	SETBMP();
	284	//set model
	285	if(!(c = mbynam(&model, inModel))) {
dd1df490	286	PrintAndLog("error: preset model '%s' not found. Use reveng -D to list presets.", inModel);
60e86577	287	return 0;
	288	}
	289	if(c < 0)
	290	return uerr("no preset models available");
	291
60e86577	292	rflags \|= R_HAVEP \| R_HAVEI \| R_HAVERI \| R_HAVERO \| R_HAVEX;
	293
	294	//set flags
	295	switch (endian) {
	296	case 'b': /* b big-endian (RefIn = false, RefOut = false ) */
	297	model.flags &= ~P_REFIN;
	298	rflags \|= R_HAVERI;
	299	/* fall through: */
	300	case 'B': /* B big-endian output (RefOut = false) */
	301	model.flags &= ~P_REFOUT;
	302	rflags \|= R_HAVERO;
	303	mnovel(&model);
	304	/* fall through: */
	305	case 'r': /* r right-justified */
	306	model.flags \|= P_RTJUST;
	307	break;
	308	case 'l': /* l little-endian input and output */
	309	model.flags \|= P_REFIN;
	310	rflags \|= R_HAVERI;
	311	/* fall through: */
	312	case 'L': /* L little-endian output */
	313	model.flags \|= P_REFOUT;
	314	rflags \|= R_HAVERO;
	315	mnovel(&model);
	316	/* fall through: */
	317	case 't': /* t left-justified */
	318	model.flags &= ~P_RTJUST;
	319	break;
	320	}
	321
	322	mcanon(&model);
	323
	324	if (reverse) {
	325	// v calculate reversed CRC
	326	/* Distinct from the -V switch as this causes
	327	* the arguments and output to be reversed as well.
	328	*/
	329	// reciprocate Poly
	330	prcp(&model.spoly);
	331
	332	/* mrev() does:
	333	* if(refout) prev(init); else prev(xorout);
	334	* but here the entire argument polynomial is
	335	* reflected, not just the characters, so RefIn
	336	* and RefOut are not inverted as with -V.
	337	* Consequently Init is the mirror image of the
	338	* one resulting from -V, and so we have:
	339	*/
	340	if(~model.flags & P_REFOUT) {
	341	prev(&model.init);
	342	prev(&model.xorout);
	343	}
	344
	345	// swap init and xorout
	346	apoly = model.init;
	347	model.init = model.xorout;
	348	model.xorout = apoly;
	349	}
	350	// c calculate CRC
	351
	352	/* in the Williams model, xorout is applied after the refout stage.
	353	* as refout is part of ptostr(), we reverse xorout here.
	354	*/
	355	if(model.flags & P_REFOUT)
356	prev(&model.xorout);
357
358	apoly = strtop(inHexStr, model.flags, ibperhx);
359
360	if(reverse)
361	prev(&apoly);
362
363	crc = pcrc(apoly, model.spoly, model.init, model.xorout, model.flags);
364
365	if(reverse)
366	prev(&crc);
367
368	string = ptostr(crc, model.flags, obperhx);
369	for (int i = 0; i < 50; i++){
370	result[i] = string[i];
371	if (result[i]==0) break;
372	}
373	free(string);
374	pfree(&crc);
375	pfree(&apoly);
376	return 1;
377	}
99789601	378	//returns a calloced string (needs to be freed)
	379	char SwapEndianStr(const char inStr, const size_t len, const uint8_t blockSize){
	380	char *tmp = calloc(len+1, sizeof(char));
	381	for (uint8_t block=0; block < (uint8_t)(len/blockSize); block++){
	382	for (size_t i = 0; i < blockSize; i+=2){
	383	tmp[i+(blockSizeblock)] = inStr[(blockSize-1-i-1)+(blockSizeblock)];
	384	tmp[i+(blockSizeblock)+1] = inStr[(blockSize-1-i)+(blockSizeblock)];
	385	}
	386	}
	387	return tmp;
	388	}
	389
	390	// takes hex string in and searches for a matching result (hex string must include checksum)
	391	int CmdrevengSearch(const char *Cmd){
	392	char inHexStr[50] = {0x00};
	393	int dataLen = param_getstr(Cmd, 0, inHexStr);
	394	if (dataLen < 4) return 0;
	395
	396	char *Models[80];
	397	int count = 0;
	398	uint8_t width[80];
	399	width[0] = 0;
	400	uint8_t crcChars = 0;
	401	char result[30];
	402	char revResult[30];
	403	int ans = GetModels(Models, &count, width);
	404	bool found = false;
	405	if (!ans) return 0;
	406
	407	// try each model and get result
	408	for (int i = 0; i < count; i++){
	409	/*if (found) {
	410	free(Models[i]);
	411	continue;
	412	}*/
	413	// round up to # of characters in this model's crc
	414	crcChars = ((width[i]+7)/8)*2;
	415	// can't test a model that has more crc digits than our data
	416	if (crcChars >= dataLen)
	417	continue;
	418	memset(result, 0, 30);
	419	char *inCRC = calloc(crcChars+1, sizeof(char));
	420	memcpy(inCRC, inHexStr+(dataLen-crcChars), crcChars);
	421
	422	char *outHex = calloc(dataLen-crcChars+1, sizeof(char));
	423	memcpy(outHex, inHexStr, dataLen-crcChars);
	424
	425	//PrintAndLog("DEBUG: dataLen: %d, crcChars: %d, Model: %s, CRC: %s, width: %d, outHex: %s",dataLen, crcChars, Models[i], inCRC, width[i], outHex);
	426	ans = RunModel(Models[i], outHex, false, 0, result);
	427	if (ans) {
	428	//test for match
	429	if (memcmp(result, inCRC, crcChars)==0){
1417a7f9	430	PrintAndLog("\nFound a possible match!\nModel: %s\nValue: %s\n",Models[i], result);
99789601	431	//optional - stop searching if found...
	432	found = true;
	433	} else {
	434	if (crcChars > 2){
	435	char *swapEndian = SwapEndianStr(result, crcChars, crcChars);
	436	if (memcmp(swapEndian, inCRC, crcChars)==0){
1417a7f9	437	PrintAndLog("\nFound a possible match!\nModel: %s\nValue EndianSwapped: %s\n",Models[i], swapEndian);
99789601	438	//optional - stop searching if found...
	439	found = true;
	440	}
	441	free(swapEndian);
	442	}
	443	}
	444	}
	445
	446	//if (!found){
	447	ans = RunModel(Models[i], outHex, true, 0, revResult);
	448	if (ans) {
	449	//test for match
	450	if (memcmp(revResult, inCRC, crcChars)==0){
1417a7f9	451	PrintAndLog("\nFound a possible match!\nModel Reversed: %s\nValue: %s\n",Models[i], revResult);
99789601	452	//optional - stop searching if found...
	453	found = true;
	454	} else {
	455	if (crcChars > 2){
	456	char *swapEndian = SwapEndianStr(revResult, crcChars, crcChars);
	457	if (memcmp(swapEndian, inCRC, crcChars)==0){
1417a7f9	458	PrintAndLog("\nFound a possible match!\nModel Reversed: %s\nValue EndianSwapped: %s\n",Models[i], swapEndian);
99789601	459	//optional - stop searching if found...
	460	found = true;
	461	}
	462	free(swapEndian);
	463	}
	464	}
	465	}
	466	//}
	467	free(inCRC);
	468	free(outHex);
	469	free(Models[i]);
	470	}
	471	if (!found) PrintAndLog("\nNo matches found\n");
	472	return 1;
1417a7f9	473	}