/* v3_utl.c */
/* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL
 * project.
 */
/* ====================================================================
 * Copyright (c) 1999-2003 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */
/* X509 v3 extension utilities */


#include <stdio.h>
#include <ctype.h>
#include "cryptlib.h"
#include <openssl/conf.h>
#include <openssl/x509v3.h>
#include <openssl/bn.h>

static char *strip_spaces(char *name);
static int sk_strcmp(const char * const *a, const char * const *b);
static STACK_OF(STRING) *get_email(X509_NAME *name, GENERAL_NAMES *gens);
static void str_free(STRING str);
static int append_ia5(STACK_OF(STRING) **sk, ASN1_IA5STRING *email);

static int ipv4_from_asc(unsigned char *v4, const char *in);
static int ipv6_from_asc(unsigned char *v6, const char *in);
static int ipv6_cb(const char *elem, int len, void *usr);
static int ipv6_hex(unsigned char *out, const char *in, int inlen);

/* Add a CONF_VALUE name value pair to stack */

int X509V3_add_value(const char *name, const char *value,
						STACK_OF(CONF_VALUE) **extlist)
{
	CONF_VALUE *vtmp = NULL;
	char *tname = NULL, *tvalue = NULL;
	if(name && !(tname = BUF_strdup(name))) goto err;
	if(value && !(tvalue = BUF_strdup(value))) goto err;;
	if(!(vtmp = (CONF_VALUE *)OPENSSL_malloc(sizeof(CONF_VALUE)))) goto err;
	if(!*extlist && !(*extlist = sk_CONF_VALUE_new_null())) goto err;
	vtmp->section = NULL;
	vtmp->name = tname;
	vtmp->value = tvalue;
	if(!sk_CONF_VALUE_push(*extlist, vtmp)) goto err;
	return 1;
	err:
	X509V3err(X509V3_F_X509V3_ADD_VALUE,ERR_R_MALLOC_FAILURE);
	if(vtmp) OPENSSL_free(vtmp);
	if(tname) OPENSSL_free(tname);
	if(tvalue) OPENSSL_free(tvalue);
	return 0;
}

int X509V3_add_value_uchar(const char *name, const unsigned char *value,
			   STACK_OF(CONF_VALUE) **extlist)
    {
    return X509V3_add_value(name,(const char *)value,extlist);
    }

/* Free function for STACK_OF(CONF_VALUE) */

void X509V3_conf_free(CONF_VALUE *conf)
{
	if(!conf) return;
	if(conf->name) OPENSSL_free(conf->name);
	if(conf->value) OPENSSL_free(conf->value);
	if(conf->section) OPENSSL_free(conf->section);
	OPENSSL_free(conf);
}

int X509V3_add_value_bool(const char *name, int asn1_bool,
						STACK_OF(CONF_VALUE) **extlist)
{
	if(asn1_bool) return X509V3_add_value(name, "TRUE", extlist);
	return X509V3_add_value(name, "FALSE", extlist);
}

int X509V3_add_value_bool_nf(char *name, int asn1_bool,
						STACK_OF(CONF_VALUE) **extlist)
{
	if(asn1_bool) return X509V3_add_value(name, "TRUE", extlist);
	return 1;
}


char *i2s_ASN1_ENUMERATED(X509V3_EXT_METHOD *method, ASN1_ENUMERATED *a)
{
	BIGNUM *bntmp = NULL;
	char *strtmp = NULL;
	if(!a) return NULL;
	if(!(bntmp = ASN1_ENUMERATED_to_BN(a, NULL)) ||
	    !(strtmp = BN_bn2dec(bntmp)) )
		X509V3err(X509V3_F_I2S_ASN1_ENUMERATED,ERR_R_MALLOC_FAILURE);
	BN_free(bntmp);
	return strtmp;
}

char *i2s_ASN1_INTEGER(X509V3_EXT_METHOD *method, ASN1_INTEGER *a)
{
	BIGNUM *bntmp = NULL;
	char *strtmp = NULL;
	if(!a) return NULL;
	if(!(bntmp = ASN1_INTEGER_to_BN(a, NULL)) ||
	    !(strtmp = BN_bn2dec(bntmp)) )
		X509V3err(X509V3_F_I2S_ASN1_INTEGER,ERR_R_MALLOC_FAILURE);
	BN_free(bntmp);
	return strtmp;
}

ASN1_INTEGER *s2i_ASN1_INTEGER(X509V3_EXT_METHOD *method, char *value)
{
	BIGNUM *bn = NULL;
	ASN1_INTEGER *aint;
	int isneg, ishex;
	int ret;
	if (!value) {
		X509V3err(X509V3_F_S2I_ASN1_INTEGER,X509V3_R_INVALID_NULL_VALUE);
		return 0;
	}
	bn = BN_new();
	if (value[0] == '-') {
		value++;
		isneg = 1;
	} else isneg = 0;

	if (value[0] == '0' && ((value[1] == 'x') || (value[1] == 'X'))) {
		value += 2;
		ishex = 1;
	} else ishex = 0;

	if (ishex) ret = BN_hex2bn(&bn, value);
	else ret = BN_dec2bn(&bn, value);

	if (!ret || value[ret]) {
		BN_free(bn);
		X509V3err(X509V3_F_S2I_ASN1_INTEGER,X509V3_R_BN_DEC2BN_ERROR);
		return 0;
	}

	if (isneg && BN_is_zero(bn)) isneg = 0;

	aint = BN_to_ASN1_INTEGER(bn, NULL);
	BN_free(bn);
	if (!aint) {
		X509V3err(X509V3_F_S2I_ASN1_INTEGER,X509V3_R_BN_TO_ASN1_INTEGER_ERROR);
		return 0;
	}
	if (isneg) aint->type |= V_ASN1_NEG;
	return aint;
}

int X509V3_add_value_int(const char *name, ASN1_INTEGER *aint,
	     STACK_OF(CONF_VALUE) **extlist)
{
	char *strtmp;
	int ret;
	if(!aint) return 1;
	if(!(strtmp = i2s_ASN1_INTEGER(NULL, aint))) return 0;
	ret = X509V3_add_value(name, strtmp, extlist);
	OPENSSL_free(strtmp);
	return ret;
}

int X509V3_get_value_bool(CONF_VALUE *value, int *asn1_bool)
{
	char *btmp;
	if(!(btmp = value->value)) goto err;
	if(!strcmp(btmp, "TRUE") || !strcmp(btmp, "true")
		 || !strcmp(btmp, "Y") || !strcmp(btmp, "y")
		|| !strcmp(btmp, "YES") || !strcmp(btmp, "yes")) {
		*asn1_bool = 0xff;
		return 1;
	} else if(!strcmp(btmp, "FALSE") || !strcmp(btmp, "false")
		 || !strcmp(btmp, "N") || !strcmp(btmp, "n")
		|| !strcmp(btmp, "NO") || !strcmp(btmp, "no")) {
		*asn1_bool = 0;
		return 1;
	}
	err:
	X509V3err(X509V3_F_X509V3_GET_VALUE_BOOL,X509V3_R_INVALID_BOOLEAN_STRING);
	X509V3_conf_err(value);
	return 0;
}

int X509V3_get_value_int(CONF_VALUE *value, ASN1_INTEGER **aint)
{
	ASN1_INTEGER *itmp;
	if(!(itmp = s2i_ASN1_INTEGER(NULL, value->value))) {
		X509V3_conf_err(value);
		return 0;
	}
	*aint = itmp;
	return 1;
}

#define HDR_NAME	1
#define HDR_VALUE	2

/*#define DEBUG*/

STACK_OF(CONF_VALUE) *X509V3_parse_list(const char *line)
{
	char *p, *q, c;
	char *ntmp, *vtmp;
	STACK_OF(CONF_VALUE) *values = NULL;
	char *linebuf;
	int state;
	/* We are going to modify the line so copy it first */
	linebuf = BUF_strdup(line);
	state = HDR_NAME;
	ntmp = NULL;
	/* Go through all characters */
	for(p = linebuf, q = linebuf; (c = *p) && (c!='\r') && (c!='\n'); p++) {

		switch(state) {
			case HDR_NAME:
			if(c == ':') {
				state = HDR_VALUE;
				*p = 0;
				ntmp = strip_spaces(q);
				if(!ntmp) {
					X509V3err(X509V3_F_X509V3_PARSE_LIST, X509V3_R_INVALID_NULL_NAME);
					goto err;
				}
				q = p + 1;
			} else if(c == ',') {
				*p = 0;
				ntmp = strip_spaces(q);
				q = p + 1;
#if 0
				printf("%s\n", ntmp);
#endif
				if(!ntmp) {
					X509V3err(X509V3_F_X509V3_PARSE_LIST, X509V3_R_INVALID_NULL_NAME);
					goto err;
				}
				X509V3_add_value(ntmp, NULL, &values);
			}
			break ;

			case HDR_VALUE:
			if(c == ',') {
				state = HDR_NAME;
				*p = 0;
				vtmp = strip_spaces(q);
#if 0
				printf("%s\n", ntmp);
#endif
				if(!vtmp) {
					X509V3err(X509V3_F_X509V3_PARSE_LIST, X509V3_R_INVALID_NULL_VALUE);
					goto err;
				}
				X509V3_add_value(ntmp, vtmp, &values);
				ntmp = NULL;
				q = p + 1;
			}

		}
	}

	if(state == HDR_VALUE) {
		vtmp = strip_spaces(q);
#if 0
		printf("%s=%s\n", ntmp, vtmp);
#endif
		if(!vtmp) {
			X509V3err(X509V3_F_X509V3_PARSE_LIST, X509V3_R_INVALID_NULL_VALUE);
			goto err;
		}
		X509V3_add_value(ntmp, vtmp, &values);
	} else {
		ntmp = strip_spaces(q);
#if 0
		printf("%s\n", ntmp);
#endif
		if(!ntmp) {
			X509V3err(X509V3_F_X509V3_PARSE_LIST, X509V3_R_INVALID_NULL_NAME);
			goto err;
		}
		X509V3_add_value(ntmp, NULL, &values);
	}
OPENSSL_free(linebuf);
return values;

err:
OPENSSL_free(linebuf);
sk_CONF_VALUE_pop_free(values, X509V3_conf_free);
return NULL;

}

/* Delete leading and trailing spaces from a string */
static char *strip_spaces(char *name)
{
	char *p, *q;
	/* Skip over leading spaces */
	p = name;
	while(*p && isspace((unsigned char)*p)) p++;
	if(!*p) return NULL;
	q = p + strlen(p) - 1;
	while((q != p) && isspace((unsigned char)*q)) q--;
	if(p != q) q[1] = 0;
	if(!*p) return NULL;
	return p;
}

/* hex string utilities */

/* Given a buffer of length 'len' return a OPENSSL_malloc'ed string with its
 * hex representation
 * @@@ (Contents of buffer are always kept in ASCII, also on EBCDIC machines)
 */

char *hex_to_string(const unsigned char *buffer, long len)
{
	char *tmp, *q;
	const unsigned char *p;
	int i;
	const static char hexdig[] = "0123456789ABCDEF";
	if(!buffer || !len) return NULL;
	if(!(tmp = OPENSSL_malloc(len * 3 + 1))) {
		X509V3err(X509V3_F_HEX_TO_STRING,ERR_R_MALLOC_FAILURE);
		return NULL;
	}
	q = tmp;
	for(i = 0, p = buffer; i < len; i++,p++) {
		*q++ = hexdig[(*p >> 4) & 0xf];
		*q++ = hexdig[*p & 0xf];
		*q++ = ':';
	}
	q[-1] = 0;
#ifdef CHARSET_EBCDIC
	ebcdic2ascii(tmp, tmp, q - tmp - 1);
#endif

	return tmp;
}

/* Give a string of hex digits convert to
 * a buffer
 */

unsigned char *string_to_hex(const char *str, long *len)
{
	unsigned char *hexbuf, *q;
	unsigned char ch, cl, *p;
	if(!str) {
		X509V3err(X509V3_F_STRING_TO_HEX,X509V3_R_INVALID_NULL_ARGUMENT);
		return NULL;
	}
	if(!(hexbuf = OPENSSL_malloc(strlen(str) >> 1))) goto err;
	for(p = (unsigned char *)str, q = hexbuf; *p;) {
		ch = *p++;
#ifdef CHARSET_EBCDIC
		ch = os_toebcdic[ch];
#endif
		if(ch == ':') continue;
		cl = *p++;
#ifdef CHARSET_EBCDIC
		cl = os_toebcdic[cl];
#endif
		if(!cl) {
			X509V3err(X509V3_F_STRING_TO_HEX,X509V3_R_ODD_NUMBER_OF_DIGITS);
			OPENSSL_free(hexbuf);
			return NULL;
		}
		if(isupper(ch)) ch = tolower(ch);
		if(isupper(cl)) cl = tolower(cl);

		if((ch >= '0') && (ch <= '9')) ch -= '0';
		else if ((ch >= 'a') && (ch <= 'f')) ch -= 'a' - 10;
		else goto badhex;

		if((cl >= '0') && (cl <= '9')) cl -= '0';
		else if ((cl >= 'a') && (cl <= 'f')) cl -= 'a' - 10;
		else goto badhex;

		*q++ = (ch << 4) | cl;
	}

	if(len) *len = q - hexbuf;

	return hexbuf;

	err:
	if(hexbuf) OPENSSL_free(hexbuf);
	X509V3err(X509V3_F_STRING_TO_HEX,ERR_R_MALLOC_FAILURE);
	return NULL;

	badhex:
	OPENSSL_free(hexbuf);
	X509V3err(X509V3_F_STRING_TO_HEX,X509V3_R_ILLEGAL_HEX_DIGIT);
	return NULL;

}

/* V2I name comparison function: returns zero if 'name' matches
 * cmp or cmp.*
 */

int name_cmp(const char *name, const char *cmp)
{
	int len, ret;
	char c;
	len = strlen(cmp);
	if((ret = strncmp(name, cmp, len))) return ret;
	c = name[len];
	if(!c || (c=='.')) return 0;
	return 1;
}

static int sk_strcmp(const char * const *a, const char * const *b)
{
	return strcmp(*a, *b);
}

STACK_OF(STRING) *X509_get1_email(X509 *x)
{
	GENERAL_NAMES *gens;
	STACK_OF(STRING) *ret;

	gens = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
	ret = get_email(X509_get_subject_name(x), gens);
	sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
	return ret;
}

STACK_OF(STRING) *X509_get1_ocsp(X509 *x)
{
	AUTHORITY_INFO_ACCESS *info;
	STACK_OF(STRING) *ret = NULL;
	int i;

	info = X509_get_ext_d2i(x, NID_info_access, NULL, NULL);
	if (!info)
		return NULL;
	for (i = 0; i < sk_ACCESS_DESCRIPTION_num(info); i++)
		{
		ACCESS_DESCRIPTION *ad = sk_ACCESS_DESCRIPTION_value(info, i);
		if (OBJ_obj2nid(ad->method) == NID_ad_OCSP)
			{
			if (ad->location->type == GEN_URI)
				{
				if (!append_ia5(&ret, ad->location->d.uniformResourceIdentifier))
					break;
				}
			}
		}
	AUTHORITY_INFO_ACCESS_free(info);
	return ret;
}

STACK_OF(STRING) *X509_REQ_get1_email(X509_REQ *x)
{
	GENERAL_NAMES *gens;
	STACK_OF(X509_EXTENSION) *exts;
	STACK_OF(STRING) *ret;

	exts = X509_REQ_get_extensions(x);
	gens = X509V3_get_d2i(exts, NID_subject_alt_name, NULL, NULL);
	ret = get_email(X509_REQ_get_subject_name(x), gens);
	sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
	sk_X509_EXTENSION_pop_free(exts, X509_EXTENSION_free);
	return ret;
}


static STACK_OF(STRING) *get_email(X509_NAME *name, GENERAL_NAMES *gens)
{
	STACK_OF(STRING) *ret = NULL;
	X509_NAME_ENTRY *ne;
	ASN1_IA5STRING *email;
	GENERAL_NAME *gen;
	int i;
	/* Now add any email address(es) to STACK */
	i = -1;
	/* First supplied X509_NAME */
	while((i = X509_NAME_get_index_by_NID(name,
					 NID_pkcs9_emailAddress, i)) >= 0) {
		ne = X509_NAME_get_entry(name, i);
		email = X509_NAME_ENTRY_get_data(ne);
		if(!append_ia5(&ret, email)) return NULL;
	}
	for(i = 0; i < sk_GENERAL_NAME_num(gens); i++)
	{
		gen = sk_GENERAL_NAME_value(gens, i);
		if(gen->type != GEN_EMAIL) continue;
		if(!append_ia5(&ret, gen->d.ia5)) return NULL;
	}
	return ret;
}

static void str_free(STRING str)
{
	OPENSSL_free(str);
}

static int append_ia5(STACK_OF(STRING) **sk, ASN1_IA5STRING *email)
{
	char *emtmp;
	/* First some sanity checks */
	if(email->type != V_ASN1_IA5STRING) return 1;
	if(!email->data || !email->length) return 1;
	if(!*sk) *sk = sk_STRING_new(sk_strcmp);
	if(!*sk) return 0;
	/* Don't add duplicates */
	if(sk_STRING_find(*sk, (char *)email->data) != -1) return 1;
	emtmp = BUF_strdup((char *)email->data);
	if(!emtmp || !sk_STRING_push(*sk, emtmp)) {
		X509_email_free(*sk);
		*sk = NULL;
		return 0;
	}
	return 1;
}

void X509_email_free(STACK_OF(STRING) *sk)
{
	sk_STRING_pop_free(sk, str_free);
}

/* Convert IP addresses both IPv4 and IPv6 into an 
 * OCTET STRING compatible with RFC3280.
 */

ASN1_OCTET_STRING *a2i_IPADDRESS(const char *ipasc)
	{
	unsigned char ipout[16];
	ASN1_OCTET_STRING *ret;
	int iplen;

	/* If string contains a ':' assume IPv6 */

	iplen = a2i_ipadd(ipout, ipasc);

	if (!iplen)
		return NULL;

	ret = ASN1_OCTET_STRING_new();
	if (!ret)
		return NULL;
	if (!ASN1_OCTET_STRING_set(ret, ipout, iplen))
		{
		ASN1_OCTET_STRING_free(ret);
		return NULL;
		}
	return ret;
	}

ASN1_OCTET_STRING *a2i_IPADDRESS_NC(const char *ipasc)
	{
	ASN1_OCTET_STRING *ret = NULL;
	unsigned char ipout[32];
	char *iptmp = NULL, *p;
	int iplen1, iplen2;
	p = strchr(ipasc,'/');
	if (!p)
		return NULL;
	iptmp = BUF_strdup(ipasc);
	if (!iptmp)
		return NULL;
	p = iptmp + (p - ipasc);
	*p++ = 0;

	iplen1 = a2i_ipadd(ipout, iptmp);

	if (!iplen1)
		goto err;

	iplen2 = a2i_ipadd(ipout + iplen1, p);

	OPENSSL_free(iptmp);
	iptmp = NULL;

	if (!iplen2 || (iplen1 != iplen2))
		goto err;

	ret = ASN1_OCTET_STRING_new();
	if (!ret)
		goto err;
	if (!ASN1_OCTET_STRING_set(ret, ipout, iplen1 + iplen2))
		goto err;

	return ret;

	err:
	if (iptmp)
		OPENSSL_free(iptmp);
	if (ret)
		ASN1_OCTET_STRING_free(ret);
	return NULL;
	}
	

int a2i_ipadd(unsigned char *ipout, const char *ipasc)
	{
	/* If string contains a ':' assume IPv6 */

	if (strchr(ipasc, ':'))
		{
		if (!ipv6_from_asc(ipout, ipasc))
			return 0;
		return 16;
		}
	else
		{
		if (!ipv4_from_asc(ipout, ipasc))
			return 0;
		return 4;
		}
	}

static int ipv4_from_asc(unsigned char *v4, const char *in)
	{
	int a0, a1, a2, a3;
	if (sscanf(in, "%d.%d.%d.%d", &a0, &a1, &a2, &a3) != 4)
		return 0;
	if ((a0 < 0) || (a0 > 255) || (a1 < 0) || (a1 > 255)
		|| (a2 < 0) || (a2 > 255) || (a3 < 0) || (a3 > 255))
		return 0;
	v4[0] = a0;
	v4[1] = a1;
	v4[2] = a2;
	v4[3] = a3;
	return 1;
	}

typedef struct {
		/* Temporary store for IPV6 output */
		unsigned char tmp[16];
		/* Total number of bytes in tmp */
		int total;
		/* The position of a zero (corresponding to '::') */
		int zero_pos;
		/* Number of zeroes */
		int zero_cnt;
	} IPV6_STAT;


static int ipv6_from_asc(unsigned char *v6, const char *in)
	{
	IPV6_STAT v6stat;
	v6stat.total = 0;
	v6stat.zero_pos = -1;
	v6stat.zero_cnt = 0;
	/* Treat the IPv6 representation as a list of values
	 * separated by ':'. The presence of a '::' will parse
 	 * as one, two or three zero length elements.
	 */
	if (!CONF_parse_list(in, ':', 0, ipv6_cb, &v6stat))
		return 0;

	/* Now for some sanity checks */

	if (v6stat.zero_pos == -1)
		{
		/* If no '::' must have exactly 16 bytes */
		if (v6stat.total != 16)
			return 0;
		}
	else 
		{
		/* If '::' must have less than 16 bytes */
		if (v6stat.total == 16)
			return 0;
		/* More than three zeroes is an error */
		if (v6stat.zero_cnt > 3)
			return 0;
		/* Can only have three zeroes if nothing else present */
		else if (v6stat.zero_cnt == 3)
			{
			if (v6stat.total > 0)
				return 0;
			}
		/* Can only have two zeroes if at start or end */
		else if (v6stat.zero_cnt == 2)
			{
			if ((v6stat.zero_pos != 0)
				&& (v6stat.zero_pos != v6stat.total))
				return 0;
			}
		else 
		/* Can only have one zero if *not* start or end */
			{
			if ((v6stat.zero_pos == 0)
				|| (v6stat.zero_pos == v6stat.total))
				return 0;
			}
		}

	/* Format result */

	/* Copy initial part */
	if (v6stat.zero_pos > 0)
		memcpy(v6, v6stat.tmp, v6stat.zero_pos);
	/* Zero middle */
	if (v6stat.total != 16)
		memset(v6 + v6stat.zero_pos, 0, 16 - v6stat.total);
	/* Copy final part */
	if (v6stat.total != v6stat.zero_pos)
		memcpy(v6 + v6stat.zero_pos + 16 - v6stat.total,
			v6stat.tmp + v6stat.zero_pos,
			v6stat.total - v6stat.zero_pos);

	return 1;
	}

static int ipv6_cb(const char *elem, int len, void *usr)
	{
	IPV6_STAT *s = usr;
	/* Error if 16 bytes written */
	if (s->total == 16)
		return 0;
	if (len == 0)
		{
		/* Zero length element, corresponds to '::' */
		if (s->zero_pos == -1)
			s->zero_pos = s->total;
		/* If we've already got a :: its an error */
		else if (s->zero_pos != s->total)
			return 0;
		s->zero_cnt++;
		}
	else 
		{
		/* If more than 4 characters could be final a.b.c.d form */
		if (len > 4)
			{
			/* Need at least 4 bytes left */
			if (s->total > 12)
				return 0;
			/* Must be end of string */
			if (elem[len])
				return 0;
			if (!ipv4_from_asc(s->tmp + s->total, elem))
				return 0;
			s->total += 4;
			}
		else
			{
			if (!ipv6_hex(s->tmp + s->total, elem, len))
				return 0;
			s->total += 2;
			}
		}
	return 1;
	}

/* Convert a string of up to 4 hex digits into the corresponding
 * IPv6 form.
 */

static int ipv6_hex(unsigned char *out, const char *in, int inlen)
	{
	unsigned char c;
	unsigned int num = 0;
	if (inlen > 4)
		return 0;
	while(inlen--)
		{
		c = *in++;
		num <<= 4;
		if ((c >= '0') && (c <= '9'))
			num |= c - '0';
		else if ((c >= 'A') && (c <= 'F'))
			num |= c - 'A' + 10;
		else if ((c >= 'a') && (c <= 'f'))
			num |=  c - 'a' + 10;
		else
			return 0;
		}
	out[0] = num >> 8;
	out[1] = num & 0xff;
	return 1;
	}


int X509V3_NAME_from_section(X509_NAME *nm, STACK_OF(CONF_VALUE)*dn_sk,
						unsigned long chtype)
	{
	CONF_VALUE *v;
	int i, mval;
	char *p, *type;
	if (!nm)
		return 0;

	for (i = 0; i < sk_CONF_VALUE_num(dn_sk); i++)
		{
		v=sk_CONF_VALUE_value(dn_sk,i);
		type=v->name;
		/* Skip past any leading X. X: X, etc to allow for
		 * multiple instances 
		 */
		for(p = type; *p ; p++) 
#ifndef CHARSET_EBCDIC
			if ((*p == ':') || (*p == ',') || (*p == '.'))
#else
			if ((*p == os_toascii[':']) || (*p == os_toascii[',']) || (*p == os_toascii['.']))
#endif
				{
				p++;
				if(*p) type = p;
				break;
				}
#ifndef CHARSET_EBCDIC
		if (*type == '+')
#else
		if (*type == os_toascii['+'])
#endif
			{
			mval = -1;
			type++;
			}
		else
			mval = 0;
		if (!X509_NAME_add_entry_by_txt(nm,type, chtype,
				(unsigned char *) v->value,-1,-1,mval))
					return 0;

		}
	return 1;
	}
