print-esp.c - platform/external/tcpdump - Git at Google

 /*	$NetBSD: print-ah.c,v 1.4 1996/05/20 00:41:16 fvdl Exp $	*/

 /*
  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
  *	The Regents of the University of California.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that: (1) source code distributions
  * retain the above copyright notice and this paragraph in its entirety, (2)
  * distributions including binary code include the above copyright notice and
  * this paragraph in its entirety in the documentation or other materials
  * provided with the distribution, and (3) all advertising materials mentioning
  * features or use of this software display the following acknowledgement:
  * ``This product includes software developed by the University of California,
  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  * the University nor the names of its contributors may be used to endorse
  * or promote products derived from this software without specific prior
  * written permission.
  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */

 #ifndef lint
 static const char rcsid[] =
     "@(#) $Header: /tcpdump/master/tcpdump/print-esp.c,v 1.29 2002-09-05 00:00:12 guy Exp $ (LBL)";
 #endif

 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif

 #include <string.h>

 #include <tcpdump-stdinc.h>

 #include <stdlib.h>

 #ifdef HAVE_LIBCRYPTO
 #include <openssl/des.h>
 #include <openssl/blowfish.h>
 #ifdef HAVE_OPENSSL_RC5_H
 #include <openssl/rc5.h>
 #endif
 #ifdef HAVE_OPENSSL_CAST_H
 #include <openssl/cast.h>
 #endif
 #endif

 #include <stdio.h>

 #include "ip.h"
 #include "esp.h"
 #ifdef INET6
 #include "ip6.h"
 #endif

 #define AVOID_CHURN 1
 #include "interface.h"
 #include "addrtoname.h"

 static struct esp_algorithm *espsecret_xform=NULL;  /* cache of decoded alg. */
 static char                 *espsecret_key=NULL;


 enum cipher { NONE,
 	      DESCBC,
 	      BLOWFISH,
 	      RC5,
 	      CAST128,
 	      DES3CBC};


 struct esp_algorithm {
 	const char   *name;
 	enum  cipher algo;
 	int          ivlen;
 	int          authlen;
 	int          replaysize;
 };

 struct esp_algorithm esp_xforms[]={
 	{"none",                  NONE,    0,  0, 0},
 	{"des-cbc",               DESCBC,  8,  0, 0},
 	{"des-cbc-hmac96",        DESCBC,  8, 12, 4},
 	{"blowfish-cbc",          BLOWFISH,8,  0, 0},
 	{"blowfish-cbc-hmac96",   BLOWFISH,8, 12, 4},
 	{"rc5-cbc",               RC5,     8,  0, 0},
 	{"rc5-cbc-hmac96",        RC5,     8, 12, 4},
 	{"cast128-cbc",           CAST128, 8,  0, 0},
 	{"cast128-cbc-hmac96",    CAST128, 8, 12, 4},
 	{"3des-cbc-hmac96",       DES3CBC, 8, 12, 4},
 	{NULL,                    NONE,    0,  0, 0}
 };

 static int hexdigit(char hex)
 {
 	if(hex >= '0' && hex <= '9') {
 		return (hex - '0');
 	} else if(hex >= 'A' && hex <= 'F') {
 		return (hex - 'A' + 10);
 	} else if(hex >= 'a' && hex <= 'f') {
 		return (hex - 'a' + 10);
 	} else {
 		printf("invalid hex digit %c in espsecret\n", hex);
 		return 0;
 	}
 }

 static int hex2byte(char *hexstring)
 {
 	int byte;

 	byte = (hexdigit(hexstring[0]) << 4) +
 		hexdigit(hexstring[1]);
 	return byte;
 }


 static void esp_print_decodesecret(void)
 {
 	char *colon;
 	int   len, i;
 	struct esp_algorithm *xf;
 	struct esp_algorithm *null_xf =
 		&esp_xforms[sizeof(esp_xforms)/sizeof(esp_xforms[0]) - 1];

 	if(espsecret == NULL) {
 		/* set to NULL transform */
 		espsecret_xform = null_xf;
 		return;
 	}

 	if(espsecret_key != NULL) {
 		return;
 	}

 	colon = strchr(espsecret, ':');
 	if(colon == NULL) {
 		printf("failed to decode espsecret: %s\n",
 		       espsecret);
 		/* set to NULL transform */
 		espsecret_xform = null_xf;
 		return;
 	}

 	len = colon - espsecret;
 	xf = esp_xforms;
 	while(xf->name && strncasecmp(espsecret, xf->name, len)!=0) {
 		xf++;
 	}
 	if(xf->name == NULL) {
 		printf("failed to find cipher algo %s\n",
 		       espsecret);
 		/* set to NULL transform */
 		espsecret_xform = null_xf;
 		return;
 	}
 	espsecret_xform = xf;

 	colon++;
 	if(colon[0]=='0' && colon[1]=='x') {
 		/* decode some hex! */
 		colon+=2;
 		len = strlen(colon) / 2;
 		espsecret_key = (char *)malloc(len);
 		if(espsecret_key == NULL) {
 		  fprintf(stderr, "%s: ran out of memory (%d) to allocate secret key\n",
 			  program_name, len);
 		  exit(2);
 		}
 		i = 0;
 		while(colon[0] != '\0' && colon[1]!='\0') {
 			espsecret_key[i]=hex2byte(colon);
 			colon+=2;
 			i++;
 		}
 	} else {
 		espsecret_key = colon;
 	}
 }

 int
 esp_print(register const u_char *bp, register const u_char *bp2,
 	  int *nhdr, int *padlen)
 {
 	register const struct newesp *esp;
 	register const u_char *ep;
 	struct ip *ip = NULL;
 #ifdef INET6
 	struct ip6_hdr *ip6 = NULL;
 #endif
 	int advance;
 	int len;
 	char *secret;
 	int ivlen = 0;
 	u_char *ivoff;
 #ifdef HAVE_LIBCRYPTO
 	u_char *p;
 #endif

 	esp = (struct newesp *)bp;
 	secret = NULL;

 #if 0
 	/* keep secret out of a register */
 	p = (u_char *)&secret;
 #endif

 	/* 'ep' points to the end of available data. */
 	ep = snapend;

 	if ((u_char *)(esp + 1) >= ep) {
 		fputs("[|ESP]", stdout);
 		goto fail;
 	}
 	printf("ESP(spi=0x%08x", (u_int32_t)ntohl(esp->esp_spi));
 	printf(",seq=0x%x", (u_int32_t)ntohl(esp->esp_seq));
 	printf(")");

 	/* if we don't have decryption key, we can't decrypt this packet. */
 	if (!espsecret)
 		goto fail;

 	if(!espsecret_xform) {
 		esp_print_decodesecret();
 	}
 	if(espsecret_xform->name == NULL) {
 		goto fail;
 	}

 	ip = (struct ip *)bp2;
 	switch (IP_V(ip)) {
 #ifdef INET6
 	case 6:
 		ip6 = (struct ip6_hdr *)bp2;
 		ip = NULL;
 		/* we do not attempt to decrypt jumbograms */
 		if (!ntohs(ip6->ip6_plen))
 			goto fail;
 		/* if we can't get nexthdr, we do not need to decrypt it */
 		len = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
 		break;
 #endif /*INET6*/
 	case 4:
 		/* nexthdr & padding are in the last fragment */
 		if (ntohs(ip->ip_off) & IP_MF)
 			goto fail;
 #ifdef INET6
 		ip6 = NULL;
 #endif
 		len = ntohs(ip->ip_len);
 		break;
 	default:
 		goto fail;
 	}

 	/* if we can't get nexthdr, we do not need to decrypt it */
 	if (ep - bp2 < len)
 		goto fail;

 	ivoff = (u_char *)(esp + 1) + espsecret_xform->replaysize;
 	ivlen = espsecret_xform->ivlen;
 	secret = espsecret_key;

 	switch (espsecret_xform->algo) {
 	case DESCBC:
 #ifdef HAVE_LIBCRYPTO
 	    {
 		u_char iv[8];
 #if OPENSSL_VERSION_NUMBER >= 0x00907000L
 		DES_key_schedule schedule;
 #else
 		des_key_schedule schedule;
 #endif

 		switch (ivlen) {
 		case 4:
 			memcpy(iv, ivoff, 4);
 			memcpy(&iv[4], ivoff, 4);
 			p = &iv[4];
 			*p++ ^= 0xff;
 			*p++ ^= 0xff;
 			*p++ ^= 0xff;
 			*p++ ^= 0xff;
 			break;
 		case 8:
 			memcpy(iv, ivoff, 8);
 			break;
 		default:
 			goto fail;
 		}
 		p = ivoff + ivlen;

 #if OPENSSL_VERSION_NUMBER >= 0x00907000L
 		DES_set_key_unchecked((DES_cblock *)secret, schedule);

 		DES_cbc_encrypt((const unsigned char *)p, p,
 			(long)(ep - p), schedule, (DES_cblock *)iv,
 			DES_DECRYPT);
 #else
 		des_check_key = 0;
 		des_set_key((void *)secret, schedule);

 		des_cbc_encrypt((void *)p, (void *)p,
 			(long)(ep - p), schedule, (void *)iv,
 			DES_DECRYPT);
 #endif
 		advance = ivoff - (u_char *)esp + ivlen;
 		break;
 	    }
 #else
 		goto fail;
 #endif /*HAVE_LIBCRYPTO*/

 	case BLOWFISH:
 #ifdef HAVE_LIBCRYPTO
 	    {
 		BF_KEY schedule;

 		BF_set_key(&schedule, strlen(secret), secret);

 		p = ivoff + ivlen;
 		BF_cbc_encrypt(p, p, (long)(ep - p), &schedule, ivoff,
 			BF_DECRYPT);
 		advance = ivoff - (u_char *)esp + ivlen;
 		break;
 	    }
 #else
 		goto fail;
 #endif /*HAVE_LIBCRYPTO*/

 	case RC5:
 #if defined(HAVE_LIBCRYPTO) && defined(HAVE_RC5_H)
 	    {
 		RC5_32_KEY schedule;

 		RC5_32_set_key(&schedule, strlen(secret), secret,
 			RC5_16_ROUNDS);

 		p = ivoff + ivlen;
 		RC5_32_cbc_encrypt(p, p, (long)(ep - p), &schedule, ivoff,
 			RC5_DECRYPT);
 		advance = ivoff - (u_char *)esp + ivlen;
 		break;
 	    }
 #else
 		goto fail;
 #endif /*HAVE_LIBCRYPTO*/

 	case CAST128:
 #if defined(HAVE_LIBCRYPTO) && defined(HAVE_CAST_H) && !defined(HAVE_BUGGY_CAST128)
 	    {
 		CAST_KEY schedule;

 		CAST_set_key(&schedule, strlen(secret), secret);

 		p = ivoff + ivlen;
 		CAST_cbc_encrypt(p, p, (long)(ep - p), &schedule, ivoff,
 			CAST_DECRYPT);
 		advance = ivoff - (u_char *)esp + ivlen;
 		break;
 	    }
 #else
 		goto fail;
 #endif /*HAVE_LIBCRYPTO*/

 	case DES3CBC:
 #if defined(HAVE_LIBCRYPTO)
 	    {
 #if OPENSSL_VERSION_NUMBER >= 0x00907000L
 		DES_key_schedule s1, s2, s3;

 		DES_set_odd_parity((DES_cblock *)secret);
 		DES_set_odd_parity((DES_cblock *)(secret + 8));
 		DES_set_odd_parity((DES_cblock *)(secret + 16));
 		if(DES_set_key_checked((DES_cblock *)secret, s1) != 0) {
 		  printf("failed to schedule key 1\n");
 		}
 		if(DES_set_key_checked((DES_cblock *)(secret + 8), s2)!=0) {
 		  printf("failed to schedule key 2\n");
 		}
 		if(DES_set_key_checked((DES_cblock *)(secret + 16), s3)!=0) {
 		  printf("failed to schedule key 3\n");
 		}

 		p = ivoff + ivlen;
 		DES_ede3_cbc_encrypt((const unsigned char *)p, p,
 				     (long)(ep - p),
 				     &s1, &s2, &s3,
 				     (DES_cblock *)ivoff, DES_DECRYPT);
 #else
 		des_key_schedule s1, s2, s3;

 		des_check_key = 1;
 		des_set_odd_parity((void *)secret);
 		des_set_odd_parity((void *)(secret + 8));
 		des_set_odd_parity((void *)(secret + 16));
 		if(des_set_key((void *)secret, s1) != 0) {
 		  printf("failed to schedule key 1\n");
 		}
 		if(des_set_key((void *)(secret + 8), s2)!=0) {
 		  printf("failed to schedule key 2\n");
 		}
 		if(des_set_key((void *)(secret + 16), s3)!=0) {
 		  printf("failed to schedule key 3\n");
 		}

 		p = ivoff + ivlen;
 		des_ede3_cbc_encrypt((void *)p, (void *)p,
 				     (long)(ep - p),
 				     s1, s2, s3,
 				     (void *)ivoff, DES_DECRYPT);
 #endif
 		advance = ivoff - (u_char *)esp + ivlen;
 		break;
 	    }
 #else
 		goto fail;
 #endif /*HAVE_LIBCRYPTO*/

 	case NONE:
 	default:
 		advance = sizeof(struct newesp) + espsecret_xform->replaysize;
 		break;
 	}

 	ep = ep - espsecret_xform->authlen;
 	/* sanity check for pad length */
 	if (ep - bp < *(ep - 2))
 		goto fail;

 	if (padlen)
 		*padlen = *(ep - 2) + 2;

 	if (nhdr)
 		*nhdr = *(ep - 1);

 	printf(": ");
 	return advance;

 fail:
 	if (nhdr)
 		*nhdr = -1;
 	return 65536;
 }
	/* $NetBSD: print-ah.c,v 1.4 1996/05/20 00:41:16 fvdl Exp $ */

	/*
	* Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
	* The Regents of the University of California. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that: (1) source code distributions
	* retain the above copyright notice and this paragraph in its entirety, (2)
	* distributions including binary code include the above copyright notice and
	* this paragraph in its entirety in the documentation or other materials
	* provided with the distribution, and (3) all advertising materials mentioning
	* features or use of this software display the following acknowledgement:
	* ``This product includes software developed by the University of California,
	* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
	* the University nor the names of its contributors may be used to endorse
	* or promote products derived from this software without specific prior
	* written permission.
	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
	* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
	*/

	#ifndef lint
	static const char rcsid[] =
	"@(#) $Header: /tcpdump/master/tcpdump/print-esp.c,v 1.29 2002-09-05 00:00:12 guy Exp $ (LBL)";
	#endif

	#ifdef HAVE_CONFIG_H
	#include "config.h"
	#endif

	#include <string.h>

	#include <tcpdump-stdinc.h>

	#include <stdlib.h>

	#ifdef HAVE_LIBCRYPTO
	#include <openssl/des.h>
	#include <openssl/blowfish.h>
	#ifdef HAVE_OPENSSL_RC5_H
	#include <openssl/rc5.h>
	#endif
	#ifdef HAVE_OPENSSL_CAST_H
	#include <openssl/cast.h>
	#endif
	#endif

	#include <stdio.h>

	#include "ip.h"
	#include "esp.h"
	#ifdef INET6
	#include "ip6.h"
	#endif

	#define AVOID_CHURN 1
	#include "interface.h"
	#include "addrtoname.h"

	static struct esp_algorithm espsecret_xform=NULL; / cache of decoded alg. */
	static char *espsecret_key=NULL;


	enum cipher { NONE,
	DESCBC,
	BLOWFISH,
	RC5,
	CAST128,
	DES3CBC};



	struct esp_algorithm {
	const char *name;
	enum cipher algo;
	int ivlen;
	int authlen;
	int replaysize;
	};

	struct esp_algorithm esp_xforms[]={
	{"none", NONE, 0, 0, 0},
	{"des-cbc", DESCBC, 8, 0, 0},
	{"des-cbc-hmac96", DESCBC, 8, 12, 4},
	{"blowfish-cbc", BLOWFISH,8, 0, 0},
	{"blowfish-cbc-hmac96", BLOWFISH,8, 12, 4},
	{"rc5-cbc", RC5, 8, 0, 0},
	{"rc5-cbc-hmac96", RC5, 8, 12, 4},
	{"cast128-cbc", CAST128, 8, 0, 0},
	{"cast128-cbc-hmac96", CAST128, 8, 12, 4},
	{"3des-cbc-hmac96", DES3CBC, 8, 12, 4},
	{NULL, NONE, 0, 0, 0}
	};

	static int hexdigit(char hex)
	{
	if(hex >= '0' && hex <= '9') {
	return (hex - '0');
	} else if(hex >= 'A' && hex <= 'F') {
	return (hex - 'A' + 10);
	} else if(hex >= 'a' && hex <= 'f') {
	return (hex - 'a' + 10);
	} else {
	printf("invalid hex digit %c in espsecret\n", hex);
	return 0;
	}
	}

	static int hex2byte(char *hexstring)
	{
	int byte;

	byte = (hexdigit(hexstring[0]) << 4) +
	hexdigit(hexstring[1]);
	return byte;
	}


	static void esp_print_decodesecret(void)
	{
	char *colon;
	int len, i;
	struct esp_algorithm *xf;
	struct esp_algorithm *null_xf =
	&esp_xforms[sizeof(esp_xforms)/sizeof(esp_xforms[0]) - 1];

	if(espsecret == NULL) {
	/* set to NULL transform */
	espsecret_xform = null_xf;
	return;
	}

	if(espsecret_key != NULL) {
	return;
	}

	colon = strchr(espsecret, ':');
	if(colon == NULL) {
	printf("failed to decode espsecret: %s\n",
	espsecret);
	/* set to NULL transform */
	espsecret_xform = null_xf;
	return;
	}

	len = colon - espsecret;
	xf = esp_xforms;
	while(xf->name && strncasecmp(espsecret, xf->name, len)!=0) {
	xf++;
	}
	if(xf->name == NULL) {
	printf("failed to find cipher algo %s\n",
	espsecret);
	/* set to NULL transform */
	espsecret_xform = null_xf;
	return;
	}
	espsecret_xform = xf;

	colon++;
	if(colon[0]=='0' && colon[1]=='x') {
	/* decode some hex! */
	colon+=2;
	len = strlen(colon) / 2;
	espsecret_key = (char *)malloc(len);
	if(espsecret_key == NULL) {
	fprintf(stderr, "%s: ran out of memory (%d) to allocate secret key\n",
	program_name, len);
	exit(2);
	}
	i = 0;
	while(colon[0] != '\0' && colon[1]!='\0') {
	espsecret_key[i]=hex2byte(colon);
	colon+=2;
	i++;
	}
	} else {
	espsecret_key = colon;
	}
	}

	int
	esp_print(register const u_char bp, register const u_char bp2,
	int nhdr, int padlen)
	{
	register const struct newesp *esp;
	register const u_char *ep;
	struct ip *ip = NULL;
	#ifdef INET6
	struct ip6_hdr *ip6 = NULL;
	#endif
	int advance;
	int len;
	char *secret;
	int ivlen = 0;
	u_char *ivoff;
	#ifdef HAVE_LIBCRYPTO
	u_char *p;
	#endif

	esp = (struct newesp *)bp;
	secret = NULL;

	#if 0
	/* keep secret out of a register */
	p = (u_char *)&secret;
	#endif

	/* 'ep' points to the end of available data. */
	ep = snapend;

	if ((u_char *)(esp + 1) >= ep) {
	fputs("[\|ESP]", stdout);
	goto fail;
	}
	printf("ESP(spi=0x%08x", (u_int32_t)ntohl(esp->esp_spi));
	printf(",seq=0x%x", (u_int32_t)ntohl(esp->esp_seq));
	printf(")");

	/* if we don't have decryption key, we can't decrypt this packet. */
	if (!espsecret)
	goto fail;

	if(!espsecret_xform) {
	esp_print_decodesecret();
	}
	if(espsecret_xform->name == NULL) {
	goto fail;
	}

	ip = (struct ip *)bp2;
	switch (IP_V(ip)) {
	#ifdef INET6
	case 6:
	ip6 = (struct ip6_hdr *)bp2;
	ip = NULL;
	/* we do not attempt to decrypt jumbograms */
	if (!ntohs(ip6->ip6_plen))
	goto fail;
	/* if we can't get nexthdr, we do not need to decrypt it */
	len = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
	break;
	#endif /INET6/
	case 4:
	/* nexthdr & padding are in the last fragment */
	if (ntohs(ip->ip_off) & IP_MF)
	goto fail;
	#ifdef INET6
	ip6 = NULL;
	#endif
	len = ntohs(ip->ip_len);
	break;
	default:
	goto fail;
	}

	/* if we can't get nexthdr, we do not need to decrypt it */
	if (ep - bp2 < len)
	goto fail;

	ivoff = (u_char *)(esp + 1) + espsecret_xform->replaysize;
	ivlen = espsecret_xform->ivlen;
	secret = espsecret_key;

	switch (espsecret_xform->algo) {
	case DESCBC:
	#ifdef HAVE_LIBCRYPTO
	{
	u_char iv[8];
	#if OPENSSL_VERSION_NUMBER >= 0x00907000L
	DES_key_schedule schedule;
	#else
	des_key_schedule schedule;
	#endif

	switch (ivlen) {
	case 4:
	memcpy(iv, ivoff, 4);
	memcpy(&iv[4], ivoff, 4);
	p = &iv[4];
	*p++ ^= 0xff;
	*p++ ^= 0xff;
	*p++ ^= 0xff;
	*p++ ^= 0xff;
	break;
	case 8:
	memcpy(iv, ivoff, 8);
	break;
	default:
	goto fail;
	}
	p = ivoff + ivlen;

	#if OPENSSL_VERSION_NUMBER >= 0x00907000L
	DES_set_key_unchecked((DES_cblock *)secret, schedule);

	DES_cbc_encrypt((const unsigned char *)p, p,
	(long)(ep - p), schedule, (DES_cblock *)iv,
	DES_DECRYPT);
	#else
	des_check_key = 0;
	des_set_key((void *)secret, schedule);

	des_cbc_encrypt((void )p, (void )p,
	(long)(ep - p), schedule, (void *)iv,
	DES_DECRYPT);
	#endif
	advance = ivoff - (u_char *)esp + ivlen;
	break;
	}
	#else
	goto fail;
	#endif /HAVE_LIBCRYPTO/

	case BLOWFISH:
	#ifdef HAVE_LIBCRYPTO
	{
	BF_KEY schedule;

	BF_set_key(&schedule, strlen(secret), secret);

	p = ivoff + ivlen;
	BF_cbc_encrypt(p, p, (long)(ep - p), &schedule, ivoff,
	BF_DECRYPT);
	advance = ivoff - (u_char *)esp + ivlen;
	break;
	}
	#else
	goto fail;
	#endif /HAVE_LIBCRYPTO/

	case RC5:
	#if defined(HAVE_LIBCRYPTO) && defined(HAVE_RC5_H)
	{
	RC5_32_KEY schedule;

	RC5_32_set_key(&schedule, strlen(secret), secret,
	RC5_16_ROUNDS);

	p = ivoff + ivlen;
	RC5_32_cbc_encrypt(p, p, (long)(ep - p), &schedule, ivoff,
	RC5_DECRYPT);
	advance = ivoff - (u_char *)esp + ivlen;
	break;
	}
	#else
	goto fail;
	#endif /HAVE_LIBCRYPTO/

	case CAST128:
	#if defined(HAVE_LIBCRYPTO) && defined(HAVE_CAST_H) && !defined(HAVE_BUGGY_CAST128)
	{
	CAST_KEY schedule;

	CAST_set_key(&schedule, strlen(secret), secret);

	p = ivoff + ivlen;
	CAST_cbc_encrypt(p, p, (long)(ep - p), &schedule, ivoff,
	CAST_DECRYPT);
	advance = ivoff - (u_char *)esp + ivlen;
	break;
	}
	#else
	goto fail;
	#endif /HAVE_LIBCRYPTO/

	case DES3CBC:
	#if defined(HAVE_LIBCRYPTO)
	{
	#if OPENSSL_VERSION_NUMBER >= 0x00907000L
	DES_key_schedule s1, s2, s3;

	DES_set_odd_parity((DES_cblock *)secret);
	DES_set_odd_parity((DES_cblock *)(secret + 8));
	DES_set_odd_parity((DES_cblock *)(secret + 16));
	if(DES_set_key_checked((DES_cblock *)secret, s1) != 0) {
	printf("failed to schedule key 1\n");
	}
	if(DES_set_key_checked((DES_cblock *)(secret + 8), s2)!=0) {
	printf("failed to schedule key 2\n");
	}
	if(DES_set_key_checked((DES_cblock *)(secret + 16), s3)!=0) {
	printf("failed to schedule key 3\n");
	}

	p = ivoff + ivlen;
	DES_ede3_cbc_encrypt((const unsigned char *)p, p,
	(long)(ep - p),
	&s1, &s2, &s3,
	(DES_cblock *)ivoff, DES_DECRYPT);
	#else
	des_key_schedule s1, s2, s3;

	des_check_key = 1;
	des_set_odd_parity((void *)secret);
	des_set_odd_parity((void *)(secret + 8));
	des_set_odd_parity((void *)(secret + 16));
	if(des_set_key((void *)secret, s1) != 0) {
	printf("failed to schedule key 1\n");
	}
	if(des_set_key((void *)(secret + 8), s2)!=0) {
	printf("failed to schedule key 2\n");
	}
	if(des_set_key((void *)(secret + 16), s3)!=0) {
	printf("failed to schedule key 3\n");
	}

	p = ivoff + ivlen;
	des_ede3_cbc_encrypt((void )p, (void )p,
	(long)(ep - p),
	s1, s2, s3,
	(void *)ivoff, DES_DECRYPT);
	#endif
	advance = ivoff - (u_char *)esp + ivlen;
	break;
	}
	#else
	goto fail;
	#endif /HAVE_LIBCRYPTO/

	case NONE:
	default:
	advance = sizeof(struct newesp) + espsecret_xform->replaysize;
	break;
	}

	ep = ep - espsecret_xform->authlen;
	/* sanity check for pad length */
	if (ep - bp < *(ep - 2))
	goto fail;

	if (padlen)
	padlen = (ep - 2) + 2;

	if (nhdr)
	nhdr = (ep - 1);

	printf(": ");
	return advance;

	fail:
	if (nhdr)
	*nhdr = -1;
	return 65536;
	}