bsnmp/lib/asn1.c

/*
 * Copyright (c) 2001-2003
 *	Fraunhofer Institute for Open Communication Systems (FhG Fokus).
 *	All rights reserved.
 *
 * Author: Harti Brandt <harti@freebsd.org>
 *
 * Redistribution of this software and documentation 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 or documentation 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. Neither the name of the Institute 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 AND DOCUMENTATION IS PROVIDED BY FRAUNHOFER FOKUS
 * AND ITS CONTRIBUTORS ``AS IS'' AND ANY EXPRESS 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
 * FRAUNHOFER FOKUS 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.
 *
 * $Begemot: bsnmp/lib/asn1.c,v 1.27 2003/12/08 17:11:58 hbb Exp $
 *
 * ASN.1 for SNMP.
 */
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <inttypes.h>
#include <assert.h>
#include "asn1.h"

static void asn_error_func(const struct asn_buf *, const char *, ...);

void (*asn_error)(const struct asn_buf *, const char *, ...) = asn_error_func;

/*
 * Read the next header. This reads the tag (note, that only single
 * byte tags are supported for now) and the length field. The length field
 * is restricted to a 32-bit value.
 * All errors of this function stop the decoding.
 */
enum asn_err
asn_get_header(struct asn_buf *b, u_char *type, asn_len_t *len)
{
	u_int length;

	if (b->asn_len == 0) {
		asn_error(b, "no identifier for header");
		return (ASN_ERR_EOBUF);
	}
	*type = *b->asn_cptr;
	if ((*type & ASN_TYPE_MASK) > 0x30) {
		asn_error(b, "types > 0x30 not supported (%u)",
		    *type & ASN_TYPE_MASK);
		return (ASN_ERR_FAILED);
	}
	b->asn_cptr++;
	b->asn_len--;
	if (b->asn_len == 0) {
		asn_error(b, "no length field");
		return (ASN_ERR_EOBUF);
	}
	if (*b->asn_cptr & 0x80) {
		length = *b->asn_cptr++ & 0x7f;
		b->asn_len--;
		if (length == 0) {
			asn_error(b, "indefinite length not supported");
			return (ASN_ERR_FAILED);
		}
		if (length > ASN_MAXLENLEN) {
			asn_error(b, "long length too long (%u)", length);
			return (ASN_ERR_FAILED);
		}
		if (length > b->asn_len) {
			asn_error(b, "long length truncated");
			return (ASN_ERR_EOBUF);
		}
		*len = 0;
		while (length--) {
			*len = (*len << 8) | *b->asn_cptr++;
			b->asn_len--;
		}
	} else {
		*len = *b->asn_cptr++;
		b->asn_len--;
	}
	return (ASN_ERR_OK);
}

/*
 * Write a length field (restricted to values < 2^32-1) and return the
 * number of bytes this field takes. If ptr is NULL, the length is computed
 * but nothing is written. If the length would be too large return 0.
 */
static u_int
asn_put_len(u_char *ptr, asn_len_t len)
{
	u_int lenlen, lenlen1;
	asn_len_t tmp;

	if (len > ASN_MAXLEN) {
		asn_error(NULL, "encoding length too long: (%u)", len);
		return (0);
	}

	if (len <= 127) {
		if (ptr)
			*ptr++ = (u_char)len;
		return (1);
	} else {
		lenlen = 0;
		/* compute number of bytes for value (is at least 1) */
		for (tmp = len; tmp != 0; tmp >>= 8)
			lenlen++;
		if (ptr != NULL) {
			*ptr++ = (u_char)lenlen | 0x80;
			lenlen1 = lenlen;
			while (lenlen1-- > 0) {
				ptr[lenlen1] = len & 0xff;
				len >>= 8;
			}
		}
		return (lenlen + 1);
	}
}

/*
 * Write a header (tag and length fields).
 * Tags are restricted to one byte tags (value <= 0x30) and the
 * lenght field to 16-bit. All errors stop the encoding.
 */
enum asn_err
asn_put_header(struct asn_buf *b, u_char type, asn_len_t len)
{
	u_int lenlen;

	/* tag field */
	if ((type & ASN_TYPE_MASK) > 0x30) {
		asn_error(NULL, "types > 0x30 not supported (%u)",
		    type & ASN_TYPE_MASK);
		return (ASN_ERR_FAILED);
	}
	if (b->asn_len == 0)
		return (ASN_ERR_EOBUF);

	*b->asn_ptr++ = type;
	b->asn_len--;

	/* length field */
	if ((lenlen = asn_put_len(NULL, len)) == 0)
		return (ASN_ERR_FAILED);
	if (b->asn_len < lenlen)
		return (ASN_ERR_EOBUF);

	(void)asn_put_len(b->asn_ptr, len);
	b->asn_ptr += lenlen;
	b->asn_len -= lenlen;
	return (ASN_ERR_OK);
}


/*
 * This constructs a temporary sequence header with space for the maximum
 * length field (three byte). Set the pointer that ptr points to to the
 * start of the encoded header. This is used for a later call to
 * asn_commit_header which will fix-up the length field and move the
 * value if needed. All errors should stop the encoding.
 */
#define	TEMP_LEN (1 + ASN_MAXLENLEN + 1)
enum asn_err
asn_put_temp_header(struct asn_buf *b, u_char type, u_char **ptr)
{
	int ret;

	if (b->asn_len < TEMP_LEN)
		return (ASN_ERR_EOBUF);
	*ptr = b->asn_ptr;
	if ((ret = asn_put_header(b, type, ASN_MAXLEN)) == ASN_ERR_OK)
		assert(b->asn_ptr == *ptr + TEMP_LEN);
	return (ret);
}
enum asn_err
asn_commit_header(struct asn_buf *b, u_char *ptr)
{
	asn_len_t len;
	u_int lenlen, shift;

	/* compute length of encoded value without header */
	len = b->asn_ptr - (ptr + TEMP_LEN);

	/* insert length. may not fail. */
	lenlen = asn_put_len(ptr + 1, len);
	if (lenlen > TEMP_LEN - 1)
		return (ASN_ERR_FAILED);

	if (lenlen < TEMP_LEN - 1) {
		/* shift value down */
		shift = (TEMP_LEN - 1) - lenlen;
		memmove(ptr + 1 + lenlen, ptr + TEMP_LEN, len);
		b->asn_ptr -= shift;
		b->asn_len += shift;
	}
	return (ASN_ERR_OK);
}
#undef TEMP_LEN

/*
 * BER integer. This may be used to get a signed 64 bit integer at maximum.
 * The maximum length should be checked by the caller. This cannot overflow
 * if the caller ensures that len is at maximum 8.
 *
 * <bytes>
 */
static enum asn_err
asn_get_real_integer(struct asn_buf *b, asn_len_t len, int64_t *vp)
{
	u_int64_t val;
	int neg = 0;
	enum asn_err err;

	if (b->asn_len < len) {
		asn_error(b, "truncated integer");
		return (ASN_ERR_EOBUF);
	}
	if (len == 0) {
		asn_error(b, "zero-length integer");
		*vp = 0;
		return (ASN_ERR_BADLEN);
	}
	err = ASN_ERR_OK;
	if (len > 8)
		err = ASN_ERR_RANGE;
	else if (len > 1 &&
	    ((*b->asn_cptr == 0x00 && (b->asn_cptr[1] & 0x80) == 0) ||
	    (*b->asn_cptr == 0xff && (b->asn_cptr[1] & 0x80) == 0x80))) {
		asn_error(b, "non-minimal integer");
		err = ASN_ERR_BADLEN;
	}

	if (*b->asn_cptr & 0x80)
		neg = 1;
	val = 0;
	while (len--) {
		val <<= 8;
		val |= neg ? (u_char)~*b->asn_cptr : *b->asn_cptr;
		b->asn_len--;
		b->asn_cptr++;
	}
	if (neg) {
		*vp = -(int64_t)val - 1;
	} else
		*vp = (int64_t)val;
	return (err);
}

/*
 * Write a signed integer with the given type. The caller has to ensure
 * that the actual value is ok for this type.
 */
static enum asn_err
asn_put_real_integer(struct asn_buf *b, u_char type, int64_t ival)
{
	int i, neg = 0;
# define OCTETS 8
	u_char buf[OCTETS];
	u_int64_t val;
	enum asn_err ret;

	if (ival < 0) {
		/* this may fail if |INT64_MIN| > |INT64_MAX| and
		 * the value is between * INT64_MIN <= ival < -(INT64_MAX+1) */
		val = (u_int64_t)-(ival + 1);
		neg = 1;
	} else
		val = (u_int64_t)ival;

	/* split the value into octets */
	for (i = OCTETS - 1; i >= 0; i--) {
		buf[i] = val & 0xff;
		if (neg)
			buf[i] = ~buf[i];
		val >>= 8;
	}
	/* no leading 9 zeroes or ones */
	for (i = 0; i < OCTETS - 1; i++)
		if (!((buf[i] == 0xff && (buf[i + 1] & 0x80) != 0) ||
		    (buf[i] == 0x00 && (buf[i + 1] & 0x80) == 0)))
			break;
	if ((ret = asn_put_header(b, type, OCTETS - i)))
		return (ret);
	if (OCTETS - (u_int)i > b->asn_len)
		return (ASN_ERR_EOBUF);

	while (i < OCTETS) {
		*b->asn_ptr++ = buf[i++];
		b->asn_len--;
	}
	return (ASN_ERR_OK);
# undef OCTETS
}


/*
 * The same for unsigned 64-bitters. Here we have the problem, that overflow
 * can happen, because the value maybe 9 bytes long. In this case the
 * first byte must be 0.
 */
static enum asn_err
asn_get_real_unsigned(struct asn_buf *b, asn_len_t len, u_int64_t *vp)
{
	enum asn_err err;

	if (b->asn_len < len) {
		asn_error(b, "truncated integer");
		return (ASN_ERR_EOBUF);
	}
	if (len == 0) {
		asn_error(b, "zero-length integer");
		*vp = 0;
		return (ASN_ERR_BADLEN);
	}
	err = ASN_ERR_OK;
	*vp = 0;
	if ((*b->asn_cptr & 0x80) || (len == 9 && *b->asn_cptr != 0)) {
		/* negative integer or too larger */
		*vp = 0xffffffffffffffffULL;
		err = ASN_ERR_RANGE;
	} else if (len > 1 &&
	    *b->asn_cptr == 0x00 && (b->asn_cptr[1] & 0x80) == 0) {
		asn_error(b, "non-minimal unsigned");
		err = ASN_ERR_BADLEN;
	}

	while (len--) {
		*vp = (*vp << 8) | *b->asn_cptr++;
		b->asn_len--;
	}
	return (err);
}


/*
 * Values with the msb on need 9 octets.
 */
static int
asn_put_real_unsigned(struct asn_buf *b, u_char type, u_int64_t val)
{
	int i;
# define OCTETS 9
	u_char buf[OCTETS];
	enum asn_err ret;

	/* split the value into octets */
	for (i = OCTETS - 1; i >= 0; i--) {
		buf[i] = val & 0xff;
		val >>= 8;
	}
	/* no leading 9 zeroes */
	for (i = 0; i < OCTETS - 1; i++)
		if (!(buf[i] == 0x00 && (buf[i + 1] & 0x80) == 0))
			break;
	if ((ret = asn_put_header(b, type, OCTETS - i)))
		return (ret);
	if (OCTETS - (u_int)i > b->asn_len)
		return (ASN_ERR_EOBUF);

	while (i < OCTETS) {
		*b->asn_ptr++ = buf[i++];
		b->asn_len--;
	}
#undef OCTETS
	return (ASN_ERR_OK);
}

/*
 * The ASN.1 INTEGER type is restricted to 32-bit signed by the SMI.
 */
enum asn_err
asn_get_integer_raw(struct asn_buf *b, asn_len_t len, int32_t *vp)
{
	int64_t val;
	enum asn_err ret;

	if ((ret = asn_get_real_integer(b, len, &val)) == ASN_ERR_OK) {
		if (len > 4)
			ret = ASN_ERR_BADLEN;
		else if (val > INT32_MAX || val < INT32_MIN)
			/* may not happen */
			ret = ASN_ERR_RANGE;
		*vp = (int32_t)val;
	}
	return (ret);
}

enum asn_err
asn_get_integer(struct asn_buf *b, int32_t *vp)
{
	asn_len_t len;
	u_char type;
	enum asn_err err;

	if ((err = asn_get_header(b, &type, &len)) != ASN_ERR_OK)
		return (err);
	if (type != ASN_TYPE_INTEGER) {
		asn_error(b, "bad type for integer (%u)", type);
		return (ASN_ERR_TAG);
	}

	return (asn_get_integer_raw(b, len, vp));
}

enum asn_err
asn_put_integer(struct asn_buf *b, int32_t val)
{
	return (asn_put_real_integer(b, ASN_TYPE_INTEGER, val));
}

/*
 * OCTETSTRING
 *
 * <0x04> <len> <data ...>
 *
 * Get an octetstring. noctets must point to the buffer size and on
 * return will contain the size of the octetstring, regardless of the
 * buffer size.
 */
enum asn_err
asn_get_octetstring_raw(struct asn_buf *b, asn_len_t len, u_char *octets,
    u_int *noctets)
{
	enum asn_err err = ASN_ERR_OK;

	if (*noctets < len) {
		asn_error(b, "octetstring truncated");
		err = ASN_ERR_RANGE;
	}
	if (b->asn_len < len) {
		asn_error(b, "truncatet octetstring");
		return (ASN_ERR_EOBUF);
	}
	if (*noctets < len)
		memcpy(octets, b->asn_cptr, *noctets);
	else
		memcpy(octets, b->asn_cptr, len);
	*noctets = len;
	b->asn_cptr += len;
	b->asn_len -= len;
	return (err);
}

enum asn_err
asn_get_octetstring(struct asn_buf *b, u_char *octets, u_int *noctets)
{
	enum asn_err err;
	u_char type;
	asn_len_t len;

	if ((err = asn_get_header(b, &type, &len)) != ASN_ERR_OK)
		return (err);
	if (type != ASN_TYPE_OCTETSTRING) {
		asn_error(b, "bad type for octetstring (%u)", type);
		return (ASN_ERR_TAG);
	}
	return (asn_get_octetstring_raw(b, len, octets, noctets));
}

enum asn_err
asn_put_octetstring(struct asn_buf *b, const u_char *octets, u_int noctets)
{
	enum asn_err ret;

	if ((ret = asn_put_header(b, ASN_TYPE_OCTETSTRING, noctets)) != ASN_ERR_OK)
		return (ret);
	if (b->asn_len < noctets)
		return (ASN_ERR_EOBUF);

	memcpy(b->asn_ptr, octets, noctets);
	b->asn_ptr += noctets;
	b->asn_len -= noctets;
	return (ASN_ERR_OK);
}

/*
 * NULL
 *
 * <0x05> <0x00>
 */
enum asn_err
asn_get_null_raw(struct asn_buf *b, asn_len_t len)
{
	if (len != 0) {
		if (b->asn_len < len) {
			asn_error(b, "truncated NULL");
			return (ASN_ERR_EOBUF);
		}
		asn_error(b, "bad length for NULL (%u)", len);
		b->asn_len -= len;
		b->asn_ptr += len;
		return (ASN_ERR_BADLEN);
	}
	return (ASN_ERR_OK);
}

enum asn_err
asn_get_null(struct asn_buf *b)
{
	u_char type;
	asn_len_t len;
	enum asn_err err;

	if ((err = asn_get_header(b, &type, &len)) != ASN_ERR_OK)
		return (err);
	if (type != ASN_TYPE_NULL) {
		asn_error(b, "bad type for NULL (%u)", type);
		return (ASN_ERR_TAG);
	}
	return (asn_get_null_raw(b, len));
}

enum asn_err
asn_put_null(struct asn_buf *b)
{
	return (asn_put_header(b, ASN_TYPE_NULL, 0));
}

enum asn_err
asn_put_exception(struct asn_buf *b, u_int except)
{
	return (asn_put_header(b, ASN_CLASS_CONTEXT | except, 0));
}

/*
 * OBJID
 *
 * <0x06> <len> <subid...>
 */
enum asn_err
asn_get_objid_raw(struct asn_buf *b, asn_len_t len, struct asn_oid *oid)
{
	asn_subid_t subid;
	enum asn_err err;

	if (b->asn_len < len) {
		asn_error(b, "truncated OBJID");
		return (ASN_ERR_EOBUF);
	}
	oid->len = 0;
	if (len == 0) {
		asn_error(b, "short OBJID");
		oid->subs[oid->len++] = 0;
		oid->subs[oid->len++] = 0;
		return (ASN_ERR_BADLEN);
	}
	err = ASN_ERR_OK;
	while (len != 0) {
		if (oid->len == ASN_MAXOIDLEN) {
			asn_error(b, "OID too long (%u)", oid->len);
			b->asn_cptr += len;
			b->asn_len -= len;
			return (ASN_ERR_BADLEN);
		}
		subid = 0;
		do {
			if (len == 0) {
				asn_error(b, "unterminated subid");
				return (ASN_ERR_EOBUF);
			}
			if (subid > (ASN_MAXID >> 7)) {
				asn_error(b, "OBID subid too larger");
				err = ASN_ERR_RANGE;
			}
			subid = (subid << 7) | (*b->asn_cptr & 0x7f);
			len--;
			b->asn_len--;
		} while (*b->asn_cptr++ & 0x80);
		if (oid->len == 0) {
			if (subid < 80) {
				oid->subs[oid->len++] = subid / 40;
				oid->subs[oid->len++] = subid % 40;
			} else {
				oid->subs[oid->len++] = 2;
				oid->subs[oid->len++] = subid - 80;
			}
		} else {
			oid->subs[oid->len++] = subid;
		}
	}
	return (err);

}

enum asn_err
asn_get_objid(struct asn_buf *b, struct asn_oid *oid)
{
	u_char type;
	asn_len_t len;
	enum asn_err err;

	if ((err = asn_get_header(b, &type, &len)) != ASN_ERR_OK)
		return (err);
	if (type != ASN_TYPE_OBJID) {
		asn_error(b, "bad type for OBJID (%u)", type);
		return (ASN_ERR_TAG);
	}
	return (asn_get_objid_raw(b, len, oid));
}

enum asn_err
asn_put_objid(struct asn_buf *b, const struct asn_oid *oid)
{
	asn_subid_t first, sub;
	enum asn_err err, err1;
	u_int i, oidlen;
	asn_len_t len;

	err = ASN_ERR_OK;
	if (oid->len == 0) {
		/* illegal */
		asn_error(NULL, "short oid");
		err = ASN_ERR_RANGE;
		first = 0;
		oidlen = 2;
	} else if (oid->len == 1) {
		/* illegal */
		asn_error(b, "short oid");
		if (oid->subs[0] > 2)
			asn_error(NULL, "oid[0] too large (%u)", oid->subs[0]);
		err = ASN_ERR_RANGE;
		first = oid->subs[0] * 40;
		oidlen = 2;
	} else {
		if (oid->len > ASN_MAXOIDLEN) {
			asn_error(NULL, "oid too long %u", oid->len);
			err = ASN_ERR_RANGE;
		}
		if (oid->subs[0] > 2 ||
		    (oid->subs[0] < 2 && oid->subs[0] >= 40)) {
			asn_error(NULL, "oid out of range (%u,%u)",
			    oid->subs[0], oid->subs[1]);
			err = ASN_ERR_RANGE;
		}
		first = 40 * oid->subs[0] + oid->subs[1];
		oidlen = oid->len;
	}
	len = 0;
	for (i = 1; i < oidlen; i++) {
		sub = (i == 1) ? first : oid->subs[i];
		if (sub > ASN_MAXID) {
			asn_error(NULL, "oid subid too large");
			err = ASN_ERR_RANGE;
		}
		len += (sub <= 0x7f) ? 1
		    : (sub <= 0x3fff) ? 2
		    : (sub <= 0x1fffff) ? 3
		    : (sub <= 0xfffffff) ? 4
		    : 5;
	}
	if ((err1 = asn_put_header(b, ASN_TYPE_OBJID, len)) != ASN_ERR_OK)
		return (err1);
	if (b->asn_len < len)
		return (ASN_ERR_EOBUF);

	for (i = 1; i < oidlen; i++) {
		sub = (i == 1) ? first : oid->subs[i];
		if (sub <= 0x7f) {
			*b->asn_ptr++ = sub;
			b->asn_len--;
		} else if (sub <= 0x3fff) {
			*b->asn_ptr++ = (sub >> 7) | 0x80;
			*b->asn_ptr++ = sub & 0x7f;
			b->asn_len -= 2;
		} else if (sub <= 0x1fffff) {
			*b->asn_ptr++ = (sub >> 14) | 0x80;
			*b->asn_ptr++ = ((sub >> 7) & 0x7f) | 0x80;
			*b->asn_ptr++ = sub & 0x7f;
			b->asn_len -= 3;
		} else if (sub <= 0xfffffff) {
			*b->asn_ptr++ = (sub >> 21) | 0x80;
			*b->asn_ptr++ = ((sub >> 14) & 0x7f) | 0x80;
			*b->asn_ptr++ = ((sub >> 7) & 0x7f) | 0x80;
			*b->asn_ptr++ = sub & 0x7f;
			b->asn_len -= 4;
		} else {
			*b->asn_ptr++ = (sub >> 28) | 0x80;
			*b->asn_ptr++ = ((sub >> 21) & 0x7f) | 0x80;
			*b->asn_ptr++ = ((sub >> 14) & 0x7f) | 0x80;
			*b->asn_ptr++ = ((sub >> 7) & 0x7f) | 0x80;
			*b->asn_ptr++ = sub & 0x7f;
			b->asn_len -= 5;
		}
	}
	return (err);
}
/*
 * SEQUENCE header
 *
 * <0x10|0x20> <len> <data...>
 */
enum asn_err
asn_get_sequence(struct asn_buf *b, asn_len_t *len)
{
	u_char type;
	enum asn_err err;

	if ((err = asn_get_header(b, &type, len)) != ASN_ERR_OK)
		return (err);
	if (type != (ASN_TYPE_SEQUENCE|ASN_TYPE_CONSTRUCTED)) {
		asn_error(b, "bad sequence type %u", type);
		return (ASN_ERR_TAG);
	}
	if (*len > b->asn_len) {
		asn_error(b, "truncated sequence");
		return (ASN_ERR_EOBUF);
	}
	return (ASN_ERR_OK);
}

/*
 * Application types
 *
 * 0x40 4 MSB 2MSB 2LSB LSB
 */
enum asn_err
asn_get_ipaddress_raw(struct asn_buf *b, asn_len_t len, u_char *addr)
{
	u_int i;

	if (b->asn_len < len) {
		asn_error(b, "truncated ip-address");
		return (ASN_ERR_EOBUF);
	}
	if (len < 4) {
		asn_error(b, "short length for ip-Address %u", len);
		for (i = 0; i < len; i++)
			*addr++ = *b->asn_cptr++;
		while (i++ < len)
			*addr++ = 0;
		b->asn_len -= len;
		return (ASN_ERR_BADLEN);
	}
	for (i = 0; i < 4; i++)
		*addr++ = *b->asn_cptr++;
	b->asn_cptr += len - 4;
	b->asn_len -= len;
	return (ASN_ERR_OK);
}

enum asn_err
asn_get_ipaddress(struct asn_buf *b, u_char *addr)
{
	u_char type;
	asn_len_t len;
	enum asn_err err;

	if ((err = asn_get_header(b, &type, &len)) != ASN_ERR_OK)
		return (err);
	if (type != (ASN_CLASS_APPLICATION|ASN_APP_IPADDRESS)) {
		asn_error(b, "bad type for ip-address %u", type);
		return (ASN_ERR_TAG);
	}
	return (asn_get_ipaddress_raw(b, len, addr));
}

enum asn_err
asn_put_ipaddress(struct asn_buf *b, const u_char *addr)
{
	enum asn_err err;

	if ((err = asn_put_header(b, ASN_CLASS_APPLICATION|ASN_APP_IPADDRESS,
	    4)) != ASN_ERR_OK)
		return (err);
	if (b->asn_len < 4)
		return (ASN_ERR_EOBUF);

	memcpy(b->asn_ptr, addr, 4);
	b->asn_ptr += 4;
	b->asn_len -= 4;
	return (ASN_ERR_OK);
}


/*
 * UNSIGNED32
 *
 * 0x42|0x41 <len> ...
 */
enum asn_err
asn_get_uint32_raw(struct asn_buf *b, asn_len_t len, u_int32_t *vp)
{
	u_int64_t v;
	enum asn_err err;

	if ((err = asn_get_real_unsigned(b, len, &v)) == ASN_ERR_OK) {
		if (len > 5) {
			asn_error(b, "uint32 too long %u", len);
			err = ASN_ERR_BADLEN;
		} else if (v > UINT32_MAX) {
			asn_error(b, "uint32 too large %llu", v);
			err = ASN_ERR_RANGE;
		}
		*vp = (u_int32_t)v;
	}
	return (err);
}

enum asn_err
asn_put_uint32(struct asn_buf *b, u_char type, u_int32_t val)
{
	u_int64_t v = val;

	return (asn_put_real_unsigned(b, ASN_CLASS_APPLICATION|type, v));
}

/*
 * COUNTER64
 * 0x46 <len> ...
 */
enum asn_err
asn_get_counter64_raw(struct asn_buf *b, asn_len_t len, u_int64_t *vp)
{
	return (asn_get_real_unsigned(b, len, vp));
}

enum asn_err
asn_put_counter64(struct asn_buf *b, u_int64_t val)
{
	return (asn_put_real_unsigned(b,
	    ASN_CLASS_APPLICATION | ASN_APP_COUNTER64, val));
}

/*
 * TimeTicks
 * 0x43 <len> ...
 */
enum asn_err
asn_get_timeticks(struct asn_buf *b, u_int32_t *vp)
{
	asn_len_t len;
	u_char type;
	enum asn_err err;

	if ((err = asn_get_header(b, &type, &len)) != ASN_ERR_OK)
		return (err);
	if (type != (ASN_CLASS_APPLICATION|ASN_APP_TIMETICKS)) {
		asn_error(b, "bad type for timeticks %u", type);
		return (ASN_ERR_TAG);
	}
	return (asn_get_uint32_raw(b, len, vp));
}

enum asn_err
asn_put_timeticks(struct asn_buf *b, u_int32_t val)
{
	u_int64_t v = val;

	return (asn_put_real_unsigned(b,
	    ASN_CLASS_APPLICATION | ASN_APP_TIMETICKS, v));
}

/*
 * Construct a new OID by taking a range of sub ids of the original oid.
 */
void
asn_slice_oid(struct asn_oid *dest, const struct asn_oid *src,
    u_int from, u_int to)
{
	if (from >= to) {
		dest->len = 0;
		return;
	}
	dest->len = to - from;
	memcpy(dest->subs, &src->subs[from], dest->len * sizeof(dest->subs[0]));
}

/*
 * Append from to to
 */
void
asn_append_oid(struct asn_oid *to, const struct asn_oid *from)
{
	memcpy(&to->subs[to->len], &from->subs[0],
	    from->len * sizeof(from->subs[0]));
	to->len += from->len;
}

/*
 * Skip a value
 */
enum asn_err
asn_skip(struct asn_buf *b, asn_len_t len)
{
	if (b->asn_len < len)
		return (ASN_ERR_EOBUF);
	b->asn_cptr += len;
	b->asn_len -= len;
	return (ASN_ERR_OK);
}

/*
 * Compare two OIDs.
 *
 * o1 < o2 : -1
 * o1 > o2 : +1
 * o1 = o2 :  0
 */
int
asn_compare_oid(const struct asn_oid *o1, const struct asn_oid *o2)
{
	u_long i;

	for (i = 0; i < o1->len && i < o2->len; i++) {
		if (o1->subs[i] < o2->subs[i])
			return (-1);
		if (o1->subs[i] > o2->subs[i])
			return (+1);
	}
	if (o1->len < o2->len)
		return (-1);
	if (o1->len > o2->len)
		return (+1);
	return (0);
}

/*
 * Check whether an OID is a sub-string of another OID.
 */
int
asn_is_suboid(const struct asn_oid *o1, const struct asn_oid *o2)
{
	u_long i;

	for (i = 0; i < o1->len; i++)
		if (i >= o2->len || o1->subs[i] != o2->subs[i])
			return (0);
	return (1);
}

/*
 * Put a string representation of an oid into a user buffer. This buffer
 * is assumed to be at least ASN_OIDSTRLEN characters long.
 *
 * sprintf is assumed not to fail here.
 */
char *
asn_oid2str_r(const struct asn_oid *oid, char *buf)
{
	u_int len, i;
	char *ptr;

	if ((len = oid->len) > ASN_MAXOIDLEN)
		len = ASN_MAXOIDLEN;
	buf[0] = '\0';
	for (i = 0, ptr = buf; i < len; i++) {
		if (i > 0)
			*ptr++ = '.';
		ptr += sprintf(ptr, "%u", oid->subs[i]);
	}
	return (buf);
}

/*
 * Make a string from an OID in a private buffer.
 */
char *
asn_oid2str(const struct asn_oid *oid)
{
	static char str[ASN_OIDSTRLEN];

	return (asn_oid2str_r(oid, str));
}


static void
asn_error_func(const struct asn_buf *b, const char *err, ...)
{
	va_list ap;
	u_long i;

	fprintf(stderr, "ASN.1: ");
	va_start(ap, err);
	vfprintf(stderr, err, ap);
	va_end(ap);

	if (b != NULL) {
		fprintf(stderr, " at");
		for (i = 0; b->asn_len > i; i++)
			fprintf(stderr, " %02x", b->asn_cptr[i]);
	}
	fprintf(stderr, "\n");
}