[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 "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;
	}
	/* canonicalise the model, so the one we dump is the one we
	 * calculate with (not with -s, spoly may be blank which will
	 * normalise to zero and clear init and xorout.)
	 */
	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 "cmdmain.h"
9962091e	23	#include "cmdcrc.h"
a71ece51	24	#include "reveng/reveng.h"
	25	#include "ui.h"
	26	#include "util.h"
9962091e	27
a71ece51	28	#define MAX_ARGS 20
9962091e	29
60e86577	30	int uerr(char *msg){
	31	PrintAndLog("%s",msg);
	32	return 0;
	33	}
	34
a71ece51	35	int split(char str, char arr[MAX_ARGS]){
	36	int beginIndex = 0;
	37	int endIndex;
	38	int maxWords = MAX_ARGS;
	39	int wordCnt = 0;
	40
	41	while(1){
	42	while(isspace(str[beginIndex])){
	43	++beginIndex;
	44	}
	45	if(str[beginIndex] == '\0')
	46	break;
	47	endIndex = beginIndex;
	48	while (str[endIndex] && !isspace(str[endIndex])){
	49	++endIndex;
	50	}
	51	int len = endIndex - beginIndex;
	52	char *tmp = calloc(len + 1, sizeof(char));
	53	memcpy(tmp, &str[beginIndex], len);
	54	arr[wordCnt++] = tmp;
	55	//PrintAndLog("cnt: %d, %s",wordCnt-1, arr[wordCnt-1]);
	56	beginIndex = endIndex;
	57	if (wordCnt == maxWords)
	58	break;
	59	}
	60	return wordCnt;
	61	}
9962091e	62
	63	int CmdCrc(const char *Cmd)
	64	{
a71ece51	65	char name[] = {"reveng "};
	66	char Cmd2[50 + 7];
	67	memcpy(Cmd2, name, 7);
	68	memcpy(Cmd2 + 7, Cmd, 50);
	69	char *argv[MAX_ARGS];
	70	int argc = split(Cmd2, argv);
99789601	71
	72	if (argc == 3 && memcmp(argv[1],"-g",2)==0) {
	73	CmdrevengSearch(argv[2]);
	74	} else {
13629a71	75	reveng_main(argc, argv);
99789601	76	}
99789601	77	//PrintAndLog("DEBUG argc: %d, %s %s Cmd: %s",argc, argv[0], Cmd2, Cmd);
13629a71	78	for(int i = 0; i < argc; ++i) {
a71ece51	79	free(argv[i]);
	80	}
	81
9962091e	82	return 0;
	83	}
	84
99789601	85	//returns array of model names and the count of models returning
	86	// as well as a width array for the width of each model
	87	int GetModels(char Models[], int count, uint8_t *width){
60e86577	88	/* default values */
	89	static model_t model = {
	90	PZERO, /* no CRC polynomial, user must specify */
	91	PZERO, /* Init = 0 */
	92	P_BE, /* RefIn = false, RefOut = false, plus P_RTJUST setting in reveng.h */
	93	PZERO, /* XorOut = 0 */
	94	PZERO, /* check value unused */
	95	NULL /* no model name */
	96	};
dd1df490	97
60e86577	98	int ibperhx = 8;//, obperhx = 8;
60e86577	99	int rflags = 0, uflags = 0; /* search and UI flags */
60e86577	100	poly_t apoly, crc, qpoly = PZERO, apolys = NULL, pptr = NULL, *qptr = NULL;
	101	model_t pset = model, candmods, mptr;
	102
	103	/* stdin must be binary */
	104	#ifdef _WIN32
	105	_setmode(STDIN_FILENO, _O_BINARY);
	106	#endif /* _WIN32 */
	107
	108	SETBMP();
	109
	110	int args = 0, psets, pass;
	111	int Cnt = 0;
99789601	112	if (width[0] == 0) { //reveng -D
60e86577	113	*count = mcount();
60e86577	114	if(!*count)
	115	return uerr("no preset models available");
	116
	117	for(int mode = 0; mode < *count; ++mode) {
	118	mbynum(&model, mode);
	119	mcanon(&model);
	120	size_t size = (model.name && *model.name) ? strlen(model.name) : 6;
60e86577	121	char *tmp = calloc(size+1, sizeof(char));
	122	if (tmp==NULL)
	123	return uerr("out of memory?");
	124
	125	memcpy(tmp, model.name, size);
	126	Models[mode] = tmp;
99789601	127	width[mode] = plen(model.spoly);
60e86577	128	}
dd1df490	129	mfree(&model);
60e86577	130	} else { //reveng -s
60e86577	131
13629a71	132	if(~model.flags & P_MULXN)
13629a71	133	return uerr("cannot search for non-Williams compliant models");
60e86577	134
99789601	135	praloc(&model.spoly, (unsigned long)width[0]);
	136	praloc(&model.init, (unsigned long)width[0]);
	137	praloc(&model.xorout, (unsigned long)width[0]);
13629a71	138
13629a71	139	if(!plen(model.spoly))
99789601	140	palloc(&model.spoly, (unsigned long)width[0]);
13629a71	141	else
99789601	142	width[0] = (uint8_t)plen(model.spoly);
60e86577	143
13629a71	144	/* special case if qpoly is zero, search to end of range */
	145	if(!ptst(qpoly))
	146	rflags &= ~R_HAVEQ;
60e86577	147
13629a71	148	/* if endianness not specified, try
	149	* little-endian then big-endian.
	150	* NB: crossed-endian algorithms will not be
	151	* searched.
	152	*/
	153	/* scan against preset models */
	154	if(~uflags & C_FORCE) {
	155	pass = 0;
	156	Cnt = 0;
	157	do {
	158	psets = mcount();
	159
	160	while(psets) {
	161	mbynum(&pset, --psets);
	162
	163	/* skip if different width, or refin or refout don't match */
	164	if(plen(pset.spoly) != width[0] \|\| (model.flags ^ pset.flags) & (P_REFIN \| P_REFOUT))
	165	continue;
	166	/* skip if the preset doesn't match specified parameters */
	167	if(rflags & R_HAVEP && pcmp(&model.spoly, &pset.spoly))
	168	continue;
	169	if(rflags & R_HAVEI && psncmp(&model.init, &pset.init))
	170	continue;
	171	if(rflags & R_HAVEX && psncmp(&model.xorout, &pset.xorout))
	172	continue;
	173
	174	//for additional args (not used yet, maybe future?)
	175	apoly = pclone(pset.xorout);
	176	if(pset.flags & P_REFOUT)
	177	prev(&apoly);
	178
	179	for(qptr = apolys; qptr < pptr; ++qptr) {
	180	crc = pcrc(*qptr, pset.spoly, pset.init, apoly, 0);
	181	if(ptst(crc)) {
	182	pfree(&crc);
	183	break;
	184	} else
	185	pfree(&crc);
60e86577	186	}
13629a71	187	pfree(&apoly);
13629a71	188	if(qptr == pptr) {
99789601	189
13629a71	190	/* the selected model solved all arguments */
dd1df490	191
13629a71	192	mcanon(&pset);
	193
	194	size_t size = (pset.name && *pset.name) ? strlen(pset.name) : 6;
	195	//PrintAndLog("Size: %d, %s, count: %d",size,pset.name, Cnt);
	196	char *tmp = calloc(size+1, sizeof(char));
	197	if (tmp == NULL){
	198	PrintAndLog("out of memory?");
	199	return 0;
	200	}
	201	width[Cnt] = width[0];
	202	memcpy(tmp, pset.name, size);
	203	Models[Cnt++] = tmp;
	204	*count = Cnt;
	205	uflags \|= C_RESULT;
	206	}
60e86577	207	}
13629a71	208	mfree(&pset);
	209
	210	/* toggle refIn/refOut and reflect arguments */
60e86577	211	if(~rflags & R_HAVERI) {
	212	model.flags ^= P_REFIN \| P_REFOUT;
	213	for(qptr = apolys; qptr < pptr; ++qptr)
	214	prevch(qptr, ibperhx);
	215	}
	216	} while(~rflags & R_HAVERI && ++pass < 2);
13629a71	217	}
	218	//got everything now free the memory...
	219
	220	if(uflags & C_RESULT) {
60e86577	221	for(qptr = apolys; qptr < pptr; ++qptr)
60e86577	222	pfree(qptr);
13629a71	223	}
	224	if(!(model.flags & P_REFIN) != !(model.flags & P_REFOUT))
	225	return uerr("cannot search for crossed-endian models");
	226
	227	pass = 0;
	228	do {
	229	mptr = candmods = reveng(&model, qpoly, rflags, args, apolys);
	230	if(mptr && plen(mptr->spoly))
	231	uflags \|= C_RESULT;
	232	while(mptr && plen(mptr->spoly)) {
	233	mfree(mptr++);
	234	}
	235	free(candmods);
	236	if(~rflags & R_HAVERI) {
	237	model.flags ^= P_REFIN \| P_REFOUT;
	238	for(qptr = apolys; qptr < pptr; ++qptr)
	239	prevch(qptr, ibperhx);
	240	}
	241	} while(~rflags & R_HAVERI && ++pass < 2);
	242	for(qptr = apolys; qptr < pptr; ++qptr)
	243	pfree(qptr);
	244	free(apolys);
	245	if(~uflags & C_RESULT)
	246	return uerr("no models found");
	247	mfree(&model);
60e86577	248
60e86577	249	}
	250	return 1;
	251	}
	252
	253	//-c \|\| -v
	254	//inModel = valid model name string - CRC-8
	255	//inHexStr = input hex string to calculate crc on
	256	//reverse = reverse calc option if true
	257	//endian = {0 = calc default endian input and output, b = big endian input and output, B = big endian output, r = right justified
	258	// l = little endian input and output, L = little endian output only, t = left justified}
	259	//result = calculated crc hex string
	260	int RunModel(char inModel, char inHexStr, bool reverse, char endian, char *result){
	261	/* default values */
	262	static model_t model = {
	263	PZERO, // no CRC polynomial, user must specify
	264	PZERO, // Init = 0
	265	P_BE, // RefIn = false, RefOut = false, plus P_RTJUST setting in reveng.h
	266	PZERO, // XorOut = 0
	267	PZERO, // check value unused
	268	NULL // no model name
	269	};
	270	int ibperhx = 8, obperhx = 8;
	271	int rflags = 0; // search flags
	272	int c;
60e86577	273	poly_t apoly, crc;
	274
	275	char *string;
	276
	277	// stdin must be binary
	278	#ifdef _WIN32
	279	_setmode(STDIN_FILENO, _O_BINARY);
	280	#endif /* _WIN32 */
	281
	282	SETBMP();
	283	//set model
	284	if(!(c = mbynam(&model, inModel))) {
dd1df490	285	PrintAndLog("error: preset model '%s' not found. Use reveng -D to list presets.", inModel);
60e86577	286	return 0;
	287	}
	288	if(c < 0)
	289	return uerr("no preset models available");
	290
60e86577	291	rflags \|= R_HAVEP \| R_HAVEI \| R_HAVERI \| R_HAVERO \| R_HAVEX;
	292
	293	//set flags
	294	switch (endian) {
	295	case 'b': /* b big-endian (RefIn = false, RefOut = false ) */
	296	model.flags &= ~P_REFIN;
	297	rflags \|= R_HAVERI;
	298	/* fall through: */
	299	case 'B': /* B big-endian output (RefOut = false) */
	300	model.flags &= ~P_REFOUT;
	301	rflags \|= R_HAVERO;
	302	mnovel(&model);
	303	/* fall through: */
	304	case 'r': /* r right-justified */
	305	model.flags \|= P_RTJUST;
	306	break;
	307	case 'l': /* l little-endian input and output */
	308	model.flags \|= P_REFIN;
	309	rflags \|= R_HAVERI;
	310	/* fall through: */
	311	case 'L': /* L little-endian output */
	312	model.flags \|= P_REFOUT;
	313	rflags \|= R_HAVERO;
	314	mnovel(&model);
	315	/* fall through: */
	316	case 't': /* t left-justified */
	317	model.flags &= ~P_RTJUST;
	318	break;
	319	}
13629a71	320	/* canonicalise the model, so the one we dump is the one we
	321	* calculate with (not with -s, spoly may be blank which will
	322	* normalise to zero and clear init and xorout.)
	323	*/
60e86577	324	mcanon(&model);
60e86577	325
13629a71	326
60e86577	327	if (reverse) {
	328	// v calculate reversed CRC
	329	/* Distinct from the -V switch as this causes
	330	* the arguments and output to be reversed as well.
	331	*/
	332	// reciprocate Poly
	333	prcp(&model.spoly);
	334
	335	/* mrev() does:
	336	* if(refout) prev(init); else prev(xorout);
	337	* but here the entire argument polynomial is
	338	* reflected, not just the characters, so RefIn
	339	* and RefOut are not inverted as with -V.
	340	* Consequently Init is the mirror image of the
	341	* one resulting from -V, and so we have:
	342	*/
	343	if(~model.flags & P_REFOUT) {
	344	prev(&model.init);
	345	prev(&model.xorout);
	346	}
	347
	348	// swap init and xorout
	349	apoly = model.init;
	350	model.init = model.xorout;
	351	model.xorout = apoly;
	352	}
	353	// c calculate CRC
	354
	355	/* in the Williams model, xorout is applied after the refout stage.
	356	* as refout is part of ptostr(), we reverse xorout here.
	357	*/
	358	if(model.flags & P_REFOUT)
	359	prev(&model.xorout);
	360
	361	apoly = strtop(inHexStr, model.flags, ibperhx);
	362
	363	if(reverse)
	364	prev(&apoly);
	365
	366	crc = pcrc(apoly, model.spoly, model.init, model.xorout, model.flags);
	367
	368	if(reverse)
	369	prev(&crc);
	370
	371	string = ptostr(crc, model.flags, obperhx);
	372	for (int i = 0; i < 50; i++){
	373	result[i] = string[i];
	374	if (result[i]==0) break;
	375	}
	376	free(string);
	377	pfree(&crc);
	378	pfree(&apoly);
	379	return 1;
	380	}
99789601	381	//returns a calloced string (needs to be freed)
	382	char SwapEndianStr(const char inStr, const size_t len, const uint8_t blockSize){
	383	char *tmp = calloc(len+1, sizeof(char));
	384	for (uint8_t block=0; block < (uint8_t)(len/blockSize); block++){
	385	for (size_t i = 0; i < blockSize; i+=2){
	386	tmp[i+(blockSizeblock)] = inStr[(blockSize-1-i-1)+(blockSizeblock)];
	387	tmp[i+(blockSizeblock)+1] = inStr[(blockSize-1-i)+(blockSizeblock)];
	388	}
	389	}
	390	return tmp;
	391	}
	392
	393	// takes hex string in and searches for a matching result (hex string must include checksum)
	394	int CmdrevengSearch(const char *Cmd){
	395	char inHexStr[50] = {0x00};
	396	int dataLen = param_getstr(Cmd, 0, inHexStr);
	397	if (dataLen < 4) return 0;
	398
	399	char *Models[80];
	400	int count = 0;
	401	uint8_t width[80];
	402	width[0] = 0;
	403	uint8_t crcChars = 0;
	404	char result[30];
	405	char revResult[30];
	406	int ans = GetModels(Models, &count, width);
	407	bool found = false;
	408	if (!ans) return 0;
	409
	410	// try each model and get result
	411	for (int i = 0; i < count; i++){
	412	/*if (found) {
	413	free(Models[i]);
	414	continue;
	415	}*/
	416	// round up to # of characters in this model's crc
	417	crcChars = ((width[i]+7)/8)*2;
	418	// can't test a model that has more crc digits than our data
	419	if (crcChars >= dataLen)
	420	continue;
	421	memset(result, 0, 30);
	422	char *inCRC = calloc(crcChars+1, sizeof(char));
	423	memcpy(inCRC, inHexStr+(dataLen-crcChars), crcChars);
	424
	425	char *outHex = calloc(dataLen-crcChars+1, sizeof(char));
	426	memcpy(outHex, inHexStr, dataLen-crcChars);
	427
	428	//PrintAndLog("DEBUG: dataLen: %d, crcChars: %d, Model: %s, CRC: %s, width: %d, outHex: %s",dataLen, crcChars, Models[i], inCRC, width[i], outHex);
	429	ans = RunModel(Models[i], outHex, false, 0, result);
	430	if (ans) {
	431	//test for match
	432	if (memcmp(result, inCRC, crcChars)==0){
1417a7f9	433	PrintAndLog("\nFound a possible match!\nModel: %s\nValue: %s\n",Models[i], result);
99789601	434	//optional - stop searching if found...
	435	found = true;
	436	} else {
	437	if (crcChars > 2){
	438	char *swapEndian = SwapEndianStr(result, crcChars, crcChars);
	439	if (memcmp(swapEndian, inCRC, crcChars)==0){
1417a7f9	440	PrintAndLog("\nFound a possible match!\nModel: %s\nValue EndianSwapped: %s\n",Models[i], swapEndian);
99789601	441	//optional - stop searching if found...
	442	found = true;
	443	}
	444	free(swapEndian);
	445	}
	446	}
	447	}
	448
	449	//if (!found){
	450	ans = RunModel(Models[i], outHex, true, 0, revResult);
	451	if (ans) {
	452	//test for match
	453	if (memcmp(revResult, inCRC, crcChars)==0){
1417a7f9	454	PrintAndLog("\nFound a possible match!\nModel Reversed: %s\nValue: %s\n",Models[i], revResult);
99789601	455	//optional - stop searching if found...
	456	found = true;
	457	} else {
	458	if (crcChars > 2){
	459	char *swapEndian = SwapEndianStr(revResult, crcChars, crcChars);
	460	if (memcmp(swapEndian, inCRC, crcChars)==0){
1417a7f9	461	PrintAndLog("\nFound a possible match!\nModel Reversed: %s\nValue EndianSwapped: %s\n",Models[i], swapEndian);
99789601	462	//optional - stop searching if found...
	463	found = true;
	464	}
	465	free(swapEndian);
	466	}
	467	}
	468	}
	469	//}
	470	free(inCRC);
	471	free(outHex);
	472	free(Models[i]);
	473	}
	474	if (!found) PrintAndLog("\nNo matches found\n");
	475	return 1;
1417a7f9	476	}