encode.c

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/*
 *   This library is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU Lesser General Public
 *   License as published by the Free Software Foundation; either
 *   version 2.1 of the License, or (at your option) any later version.
 *
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *   Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/**
 * $Id: ef6f1ce808f5aebecdac92a8c814f067e8865a39 $
 *
 * @file protocols/der/encode.c
 * @brief Functions to encode DER
 *
 * @copyright 2025 Network RADIUS SAS (legal@networkradius.com)
 */
RCSID("$Id: ef6f1ce808f5aebecdac92a8c814f067e8865a39 $")
 
#include <freeradius-devel/util/dbuff.h>
#include <freeradius-devel/util/encode.h>
#include <freeradius-devel/util/proto.h>
#include <freeradius-devel/util/sbuff.h>
#include <freeradius-devel/util/struct.h>
#include <freeradius-devel/util/time.h>
#include <freeradius-devel/util/dict_ext.h>
 
#include <freeradius-devel/io/test_point.h>
 
#include "der.h"
 
typedef struct {
        uint8_t *tmp_ctx;                       //!< Temporary context for encoding.
} fr_der_encode_ctx_t;
 
/** Function signature for DER encode functions
 *
 * @param[in] dbuff             Where to encode the data.
 * @param[in] cursor            Where to encode the data from.
 * @param[in] encode_ctx        Any encode specific data.
 * @return
 *      - > 0 on success.  How many bytes were encoded.
 *      - 0 no bytes encoded.
 *      - < 0 on error.  May be the offset (as a negative value) where the error occurred.
 */
typedef ssize_t (*fr_der_encode_t)(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, fr_der_encode_ctx_t *encode_ctx);
 
typedef struct {
        fr_der_tag_constructed_t constructed;
        fr_der_encode_t          encode;
} fr_der_tag_encode_t;
 
 
static ssize_t fr_der_encode_oid_and_value(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, fr_der_encode_ctx_t *encode_ctx) CC_HINT(nonnull);
static ssize_t fr_der_encode_choice(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, fr_der_encode_ctx_t *encode_ctx) CC_HINT(nonnull);
 
/*
 *      We have per-type function names to make it clear that different types have different encoders.
 *      However, the methods to encode them are the same.  So rather than having trampoline functions, we just
 *      use defines.
 */
#define fr_der_encode_enumerated fr_der_encode_integer
 
 
static ssize_t fr_der_encode_len(fr_dbuff_t *dbuff, fr_dbuff_marker_t *length_start) CC_HINT(nonnull);
static inline CC_HINT(always_inline) ssize_t
        fr_der_encode_tag(fr_dbuff_t *dbuff, fr_der_tag_t tag_num, fr_der_tag_class_t tag_class,
                          fr_der_tag_constructed_t constructed) CC_HINT(nonnull);
static ssize_t encode_value(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, void *encode_ctx);
 
/** Compare two pairs by their tag number.
 *
 * @param[in] a First pair.
 * @param[in] b Second pair.
 * @return              -1 if a < b, 0 if a == b, 1 if a > b.
 */
static inline CC_HINT(always_inline) int8_t fr_der_pair_cmp_by_da_tag(void const *a, void const *b)
{
        fr_pair_t const *my_a = a;
        fr_pair_t const *my_b = b;
 
        return CMP_PREFER_SMALLER(fr_der_flag_der_type(my_a->da), fr_der_flag_der_type(my_b->da));
}
 
static ssize_t encode_pair(fr_dbuff_t *dbuff, UNUSED fr_da_stack_t *da_stack, UNUSED unsigned int depth, fr_dcursor_t *cursor,
                           void *encode_ctx)
{
        return encode_value(dbuff, cursor, encode_ctx);
}
 
static ssize_t fr_der_encode_boolean(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, UNUSED fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t       our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t const *vp;
        uint8_t          value;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        /*
         *      ISO/IEC 8825-1:2021
         *      8.2 Encoding of a boolean value
         *      8.2.1 The encoding of a boolean value shall be primitive.
         *              The contents octets shall consist of a single octet.
         *      8.2.2 If the boolean value is:
         *              FALSE the octet shall be zero [0x00].
         *              If the boolean value is TRUE the octet shall have any non-zero value, as a sender's option.
         *
         *      11.1 Boolean values
         *              If the encoding represents the boolean value TRUE, its single contents octet shall have all
         *              eight bits set to one [0xFF]. (Contrast with 8.2.2.)
         */
        value = vp->vp_bool;
 
        FR_DBUFF_IN_RETURN(&our_dbuff, (uint8_t)(value ? DER_BOOLEAN_TRUE : DER_BOOLEAN_FALSE));
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
static ssize_t fr_der_encode_integer(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, UNUSED fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t       our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t const *vp;
        uint64_t         value;
        uint8_t          first_octet = 0;
        size_t           i, len;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        /*
         *      ISO/IEC 8825-1:2021
         *      8.3 Encoding of an integer value
         *      8.3.1 The encoding of an integer value shall be primitive.
         *            The contents octets shall consist of one or more octets.
         *      8.3.2 If the contents octets of an integer value encoding consist of more than one octet,
         *            then the bits of the first octet and bit 8 of the second octet:
         *            a) shall not all be ones; and
         *            b) shall not all be zero.
         *            NOTE - These rules ensure that an integer value is always encoded in the smallest possible number
         *            of octets. 8.3.3 The contents octets shall be a two's complement binary number equal to the
         *            integer value, and consisting of bits 8 to 1 of the first octet, followed by bits 8 to 1 of the
         *            second octet, followed by bits 8 to 1 of each octet in turn up to and including the last octet of
         *            the contents octets.
         */
 
        /*
         *      Some 'integer' types such as serialNumber are too
         *      large for 64-bits.  So we just treat them as octet
         *      strings.
         */
        if (vp->da->type != FR_TYPE_INT64) {
                fr_assert(vp->da->type == FR_TYPE_OCTETS);
                FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, vp->vp_octets, vp->vp_length);
                return fr_dbuff_set(dbuff, &our_dbuff);
        }
 
        /*
         *      Yes, the type is FR_TYPE_INT64.  But we encode the
         *      data as-is, without caring about things like signed
         *      math.
         */
        value = vp->vp_uint64;
 
        for (i = 0, len = 0; i < sizeof(value); i++) {
                uint8_t byte = (value >> 56) & 0xff;
 
                value <<= 8;
 
                if (len == 0) {
                        first_octet = byte;
                        len++;
                        continue;
 
                } else if (len == 1) {
                        /*
                         *      8.3.2 If the contents octets of an integer value encoding consist of more than one
                         *      octet, then the bits of the first octet and bit 8 of the second octet: a) shall not all
                         *      be ones; and b) shall not all be zero.
                         */
                        if ((first_octet == 0xff && (byte & 0x80)) || ((first_octet == 0x00) && (byte >> 7 == 0))) {
                                if (i == sizeof(value) - 1) {
                                        /*
                                         *      If this is the only byte, then we can encode it as a single byte.
                                         */
                                        FR_DBUFF_IN_RETURN(&our_dbuff, byte);
                                        continue;
                                }
 
                                first_octet = byte;
                                continue;
 
                        } else {
                                FR_DBUFF_IN_RETURN(&our_dbuff, first_octet);
                                FR_DBUFF_IN_RETURN(&our_dbuff, byte);
                                len++;
                                continue;
                        }
                }
 
                FR_DBUFF_IN_RETURN(&our_dbuff, byte);
                len++;
        }
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
static ssize_t fr_der_encode_bitstring(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t const *vp;
        ssize_t          slen;
        uint8_t          unused_bits = 0;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        /*
         *      ISO/IEC 8825-1:2021
         *      8.6 Encoding of a bitstring value
         *              8.6.1 The encoding of a bitstring value shall be either primitive or constructed at the option
         *                    of the sender.
         *                      NOTE - Where it is necessary to transfer part of a bit string before the entire
         *                             bitstring is available, the constructed encoding is used.
         *              8.6.2 The contents octets for the primitive encoding shall contain an initial octet followed
         *                    by zero, one or more subsequent octets.
         *                      8.6.2.1 The bits in the bitstring value, commencing with the leading bit and proceeding
         *                              to the trailing bit, shall be placed in bits 8 to 1 of the first subsequent
         *                              octet, followed by bits 8 to 1 of the second subsequent octet, followed by bits
         *                              8 to 1 of each octet in turn, followed by as many bits as are needed of the
         *                              final subsequent octet, commencing with bit 8.
         *                              NOTE - The terms "leading bit" and "trailing bit" are defined in
         *                                     Rec. ITU-T X.680 | ISO/IEC 8824-1, 22.2.
         *                      8.6.2.2 The initial octet shall encode, as an unsigned binary integer with bit 1 as the
         *                              least significant bit, the number of unused bits in the final subsequent octet.
         *                              The number shall be in the range zero to seven.
         *                      8.6.2.3 If the bitstring is empty, there shall be no subsequent octets, and the initial
         *                              octet shall be zero.
         *
         *      10.2 String encoding forms
         *              For bitstring, octetstring and restricted character string types, the constructed form of
         *              encoding shall not be used. (Contrast with 8.23.6.)
         *
         *      11.2 Unused bits 11.2.1 Each unused bit in the final octet of the encoding of a bit string value shall
         *           be set to zero.
         */
 
        if (fr_type_is_struct(vp->vp_type)) {
                /*
                 *      For struct type, we need to encode the struct as a bitstring using the
                 *      fr_struct_to_network function.
                 */
                unsigned int      depth = vp->da->depth - 1;
                fr_da_stack_t     da_stack;
                fr_dbuff_t        work_dbuff = FR_DBUFF(&our_dbuff);
                fr_dbuff_marker_t unused_bits_marker;
                uint8_t           last_byte = 0;
 
                fr_dbuff_marker(&unused_bits_marker, &work_dbuff);
                FR_DBUFF_ADVANCE_RETURN(&work_dbuff, 1);
 
                fr_proto_da_stack_build(&da_stack, vp->da);
 
                FR_PROTO_STACK_PRINT(&da_stack, depth);
 
                slen = fr_struct_to_network(&work_dbuff, &da_stack, depth, cursor, encode_ctx, NULL, NULL);
                if (slen < 0) {
                        fr_strerror_printf("Failed to encode struct: %s", fr_strerror());
                        return slen;
                }
 
                /*
                 *      We need to trim any empty trailing octets
                 */
                while ((slen > 1) && (fr_dbuff_current(&work_dbuff) != fr_dbuff_start(&work_dbuff))) {
                        uint8_t byte;
 
                        /*
                         *      Move the dbuff cursor back by one byte
                         */
                        fr_dbuff_set(&work_dbuff, fr_dbuff_current(&work_dbuff) - sizeof(byte));
 
                        if (fr_dbuff_out(&byte, &work_dbuff) < 0) {
                                fr_strerror_const("Failed to read byte");
                                return -1;
                        }
 
                        if (byte != 0) break;
 
                        /*
                         *      Trim this byte from the buff
                         */
                        fr_dbuff_set_end(&work_dbuff, fr_dbuff_current(&work_dbuff) - sizeof(byte));
                        fr_dbuff_set(&work_dbuff, fr_dbuff_current(&work_dbuff) - (sizeof(byte) * 2));
                        slen--;
                }
 
                /*
                 *      Grab the last octet written to the dbuff and count the number of trailing 0 bits
                 */
                if (fr_dbuff_out(&last_byte, &work_dbuff) < 0) {
                        fr_strerror_const("Failed to read last byte");
                        return -1;
                }
 
                while ((last_byte != 0) && ((last_byte & 0x01) == 0)) {
                        unused_bits++;
                        last_byte >>= 1;
                }
 
                /*
                 *      Write the unused bits
                 */
                fr_dbuff_set(&our_dbuff, fr_dbuff_current(&unused_bits_marker));
                FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, &unused_bits, 1);
 
                /*
                 *      Copy the work dbuff to the output dbuff
                 */
                fr_dbuff_set(&work_dbuff, &our_dbuff);
                FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, &work_dbuff, (size_t)slen);
 
                return fr_dbuff_set(dbuff, &our_dbuff);
        }
 
        /*
         *      For octets type, we do not need to write the unused bits portion
         *      because this information should be retained when encoding/decoding.
         */
        if (vp->vp_length == 0) {
                FR_DBUFF_IN_RETURN(&our_dbuff, (uint8_t) 0x00);
 
        } else {
                FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, vp->vp_octets, vp->vp_length);
        }
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
static ssize_t fr_der_encode_ipv4_addr(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, UNUSED fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t       our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t const *vp;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        /*
         *      RFC3779 Section 2.1.1.
         *
         *      An IP address or prefix is encoded in the IP address delegation
         *      extension as a DER-encoded ASN.1 BIT STRING containing the constant
         *      most-significant bits.  Recall [X.690] that the DER encoding of a BIT
         *      STRING consists of the BIT STRING type (0x03), followed by (an
         *      encoding of) the number of value octets, followed by the value.  The
         *      value consists of an "initial octet" that specifies the number of
         *      unused bits in the last value octet, followed by the "subsequent
         *      octets" that contain the octets of the bit string.  (For IP
         *      addresses, the encoding of the length will be just the length.)
         */
 
        /*
         *      The number of unused bits in the last byte is always zero.
         */
        FR_DBUFF_IN_RETURN(&our_dbuff, (uint8_t) 0x00);
        FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, (uint8_t const *) &vp->vp_ipv4addr, sizeof(vp->vp_ipv4addr));
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
static ssize_t fr_der_encode_ipv4_prefix(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, UNUSED fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t       our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t const *vp;
        size_t          len;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        if (vp->vp_ip.prefix == 0) {
                FR_DBUFF_IN_RETURN(&our_dbuff, (uint8_t) 0x00);
                return fr_dbuff_set(dbuff, &our_dbuff);
        }
 
        /*
         *      RFC3779 Section 2.1.1.
         *
         *      An IP address or prefix is encoded in the IP address delegation
         *      extension as a DER-encoded ASN.1 BIT STRING containing the constant
         *      most-significant bits.  Recall [X.690] that the DER encoding of a BIT
         *      STRING consists of the BIT STRING type (0x03), followed by (an
         *      encoding of) the number of value octets, followed by the value.  The
         *      value consists of an "initial octet" that specifies the number of
         *      unused bits in the last value octet, followed by the "subsequent
         *      octets" that contain the octets of the bit string.  (For IP
         *      addresses, the encoding of the length will be just the length.)
         */
        if (vp->vp_ip.prefix == 32) {
                FR_DBUFF_IN_RETURN(&our_dbuff, (uint8_t) 0x00);
                FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, (uint8_t const *) &vp->vp_ipv4addr, sizeof(vp->vp_ipv4addr));
                return fr_dbuff_set(dbuff, &our_dbuff);
        }
 
        FR_DBUFF_IN_RETURN(&our_dbuff, (uint8_t) (8 - (vp->vp_ip.prefix & 0x07)));
 
        len = (vp->vp_ip.prefix + 0x07) >> 3;
 
        if (len) FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, (uint8_t const *) &vp->vp_ipv4addr, len);
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
static ssize_t fr_der_encode_ipv6_addr(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, UNUSED fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t       our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t const *vp;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        /*
         *      RFC3779 Section 2.1.1.
         *
         *      An IP address or prefix is encoded in the IP address delegation
         *      extension as a DER-encoded ASN.1 BIT STRING containing the constant
         *      most-significant bits.  Recall [X.690] that the DER encoding of a BIT
         *      STRING consists of the BIT STRING type (0x03), followed by (an
         *      encoding of) the number of value octets, followed by the value.  The
         *      value consists of an "initial octet" that specifies the number of
         *      unused bits in the last value octet, followed by the "subsequent
         *      octets" that contain the octets of the bit string.  (For IP
         *      addresses, the encoding of the length will be just the length.)
         */
 
        /*
         *      The number of unused bits in the last byte is always zero.
         */
        FR_DBUFF_IN_RETURN(&our_dbuff, (uint8_t) 0x00);
        FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, (uint8_t const *) &vp->vp_ipv6addr, sizeof(vp->vp_ipv6addr));
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
static ssize_t fr_der_encode_ipv6_prefix(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, UNUSED fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t       our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t const *vp;
        size_t          len;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        /*
         *      RFC3779 Section 2.1.1.
         *
         *      An IP address or prefix is encoded in the IP address delegation
         *      extension as a DER-encoded ASN.1 BIT STRING containing the constant
         *      most-significant bits.  Recall [X.690] that the DER encoding of a BIT
         *      STRING consists of the BIT STRING type (0x03), followed by (an
         *      encoding of) the number of value octets, followed by the value.  The
         *      value consists of an "initial octet" that specifies the number of
         *      unused bits in the last value octet, followed by the "subsequent
         *      octets" that contain the octets of the bit string.  (For IP
         *      addresses, the encoding of the length will be just the length.)
         */
 
        if (vp->vp_ip.prefix == 128) {
                FR_DBUFF_IN_RETURN(&our_dbuff, (uint8_t) 0x00);
                FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, (uint8_t const *) &vp->vp_ipv6addr, sizeof(vp->vp_ipv6addr));
                return fr_dbuff_set(dbuff, &our_dbuff);
        }
 
        FR_DBUFF_IN_RETURN(&our_dbuff, (uint8_t) (8 - (vp->vp_ip.prefix & 0x07)));
 
        len = (vp->vp_ip.prefix + 0x07) >> 3;
 
        if (len) FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, (uint8_t const *) &vp->vp_ipv6addr, len);
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
 
static ssize_t fr_der_encode_combo_ip(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, UNUSED fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t       our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t const *vp;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        /*
         *      RFC5280 Section 4.2.1.6
         *
         *      When the subjectAltName extension contains an iPAddress, the address
         *      MUST be stored in the octet string in "network byte order", as
         *      specified in [RFC791].  The least significant bit (LSB) of each octet
         *      is the LSB of the corresponding byte in the network address.  For IP
         *      version 4, as specified in [RFC791], the octet string MUST contain
         *      exactly four octets.  For IP version 6, as specified in
         *      [RFC2460], the octet string MUST contain exactly sixteen octets.
         */
        if (vp->vp_ip.af == AF_INET) {
                FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, (uint8_t const *) &vp->vp_ipv4addr, sizeof(vp->vp_ipv4addr));
        } else {
                FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, (uint8_t const *) &vp->vp_ipv6addr, sizeof(vp->vp_ipv6addr));
        }
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
 
static ssize_t fr_der_encode_octetstring(fr_dbuff_t *dbuff, fr_dcursor_t *cursor,
                                         UNUSED fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t      our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t const *vp;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        /* can be raw! */
 
        /*
         *      ISO/IEC 8825-1:2021
         *      8.7 Encoding of an octetstring value
         *              8.7.1 The encoding of an octetstring value shall be either primitive or constructed at the
         *                    option of the sender.
         *                      NOTE - Where it is necessary to transfer part of an octet string before the entire
         *                             octetstring is available, the constructed encoding is used.
         *              8.7.2 The primitive encoding contains zero, one or more contents octets equal in value to the
         *                    octets in the data value, in the order they appear in the data value, and with the most
         *                    significant bit of an octet of the data value aligned with the most significant bit of an
         *                    octet of the contents octets.
         *              8.7.3 The contents octets for the constructed encoding shall consist of zero, one, or more
         *                    encodings.
         *                      NOTE - Each such encoding includes identifier, length, and contents octets, and may
         *                             include end-of-contents octets if it is constructed.
         *                      8.7.3.1 To encode an octetstring value in this way, it is segmented. Each segment shall
         *                             consist of a series of consecutive octets of the value. There shall be no
         *                             significance placed on the segment boundaries.
         *                              NOTE - A segment may be of size zero, i.e. contain no octets.
         *
         *      10.2 String encoding forms
         *              For bitstring, octetstring and restricted character string types, the constructed form of
         *              encoding shall not be used. (Contrast with 8.23.6.)
         */
        FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, vp->vp_octets, vp->vp_length);
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
 
static ssize_t fr_der_encode_null(UNUSED fr_dbuff_t *dbuff, fr_dcursor_t *cursor,
                                  UNUSED fr_der_encode_ctx_t *encode_ctx)
{
        fr_pair_t const *vp;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        /*
         *      ISO/IEC 8825-1:2021
         *      8.8 Encoding of a null value
         *      8.8.1 The encoding of a null value shall be primitive.
         *      8.8.2 The contents octets shall not contain any octets.
         *              NOTE - The length must be zero.
         */
        if (vp->vp_length != 0) {
                fr_strerror_printf("Null has non-zero length %zu", vp->vp_length);
                return -1;
        }
 
        return 0;
}
 
static ssize_t fr_der_encode_oid_from_value(fr_dbuff_t *dbuff, uint64_t value, uint64_t *component, int *count)
{
        fr_dbuff_t      our_dbuff;
        int             i;
        uint64_t        oid;
 
        /*
         *      The first subidentifier is the encoding of the first two object identifier components, encoded as:
         *              (X * 40) + Y
         *      where X is the first number and Y is the second number.
         *      The first number is 0, 1, or 2.
         */
        if (*count == 0) {
                if (!((value == 0) || (value == 1) || (value == 2))) {
                        fr_strerror_printf("Invalid value %" PRIu64 " for initial component", value);
                        return -1;
                }
 
                *component = value;
                (*count)++;
                return 0;
        }
 
        if (*count == 1) {
                if ((*component < 2) && (value > 40)) {
                        fr_strerror_printf("Invalid value %" PRIu64 " for second component", value);
                        return -1;
                }
 
                oid = *component * 40 + value;
        } else {
                oid = value;
        }
 
        our_dbuff = FR_DBUFF(dbuff);
 
        /*
         *      Encode the number as 7-bit chunks.  Just brute-force over all bits, as doing that ends
         *      up being fast enough.
         *
         *      i.e. if we did anything else to count bits, it would end up with pretty much the same
         *      code.
         */
        for (i = 63; i >= 0; i -= 7) {
                uint8_t more, part;
 
                part = (oid >> i) & 0x7f;
                if (!part) continue;
 
                more = ((uint8_t) (i > 0)) << 7;
 
                FR_DBUFF_IN_RETURN(&our_dbuff, (uint8_t) (more | part));
        }
 
        (*count)++;
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
static ssize_t fr_der_encode_oid(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, UNUSED fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t      our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t const *vp;
        uint64_t        component;
        int             count = 0;
        unsigned long long oid;
        char const *start;
        char     *end = NULL;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        /*
         *      ISO/IEC 8825-1:2021
         *      8.19 Encoding of an object identifier value
         *      8.19.1 The encoding of an object identifier value shall be primitive.
         *      8.19.2 The contents octets shall be an (ordered) list of encodings of subidentifiers (see 8.19.3
         *             and 8.19.4) concatenated together. Each subidentifier is represented as a series of
         *             (one or more) octets. Bit 8 of each octet indicates whether it is the last in the series: bit 8
         *             of the last octet is zero; bit 8 of each preceding octet is one. Bits 7 to 1 of the octets in
         *             the series collectively encode the subidentifier. Conceptually, these groups of bits are
         *             concatenated to form an unsigned binary number whose most significant bit is bit 7 of the first
         *             octet and whose least significant bit is bit 1 of the last octet. The subidentifier shall be
         *             encoded in the fewest possible octets, that is, the leading octet of the subidentifier shall not
         *             have the value 8016.
         *      8.19.3 The number of subidentifiers (N) shall be one less than the number of object identifier
         *              components in the object identifier value being encoded. 8.19.4 The numerical value of the
         *              first subidentifier is derived from the values of the first two object identifier components in
         *              the object identifier value being encoded, using the formula: (X*40) + Y where X is the value
         *              of the first object identifier component and Y is the value of the second object identifier
         *              component. NOTE - This packing of the first two object identifier components recognizes that
         *              only three values are allocated from the root node, and at most 39 subsequent values from nodes
         *              reached by X = 0 and X = 1. 8.19.5 The numerical value of the ith subidentifier, (2 <= i <= N) is
         *              that of the (i + 1)th object identifier component.
         */
 
 
        /*
         *      Parse each OID component.
         */
        for (start = vp->vp_strvalue; *start != '\0'; start = end + 1) {
                ssize_t slen;
 
                /*
                 *      Parse the component.
                 */
                oid = strtoull(start, &end, 10);
                if ((oid == ULLONG_MAX) || (*end && (*end != '.'))) {
                        fr_strerror_const("Invalid OID");
                        return -1;
                }
 
                slen = fr_der_encode_oid_from_value(&our_dbuff, oid, &component, &count);
                if (slen < 0) return -1;
        }
 
        if (count <= 2) {
                fr_strerror_printf("Invalid OID '%s' - too short", vp->vp_strvalue);
                return -1;
        }
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
static ssize_t fr_der_encode_sequence(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, fr_der_encode_ctx_t *encode_ctx)
{
        fr_pair_t             *vp;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        fr_assert(fr_type_is_group(vp->vp_type) || fr_type_is_tlv(vp->vp_type));
 
        /*
         *      ISO/IEC 8825-1:2021
         *      8.9 Encoding of a sequence value
         *              8.9.1 The encoding of a sequence value shall be constructed.
         *              8.9.2 The contents octets shall consist of the complete encoding of one data value from each of
         *                    the types listed in the ASN.1 definition of the sequence type, in the order of their
         *                    appearance in the definition, unless the type was referenced with the keyword OPTIONAL
         *                    or the keyword DEFAULT.
         *              8.9.3 The encoding of a data value may, but need not, be present for a type referenced with the
         *                    keyword OPTIONAL or the keyword DEFAULT. If present, it shall appear in the order of
         *                    appearance of the corresponding type in the ASN.1 definition.
         *
         *      11.5 Set and sequence components with default value
         *              The encoding of a set value or sequence value shall not include an encoding for any component
         *              value which is equal to its default value.
         */
        if (fr_type_is_group(vp->vp_type) && fr_der_flag_is_oid_and_value(vp->da)) {
                return fr_der_encode_oid_and_value(dbuff, cursor, encode_ctx);
        }
 
        return fr_der_encode_choice(dbuff, cursor, encode_ctx);
}
 
typedef struct {
        uint8_t *data;          //!< Pointer to the start of the encoded item (beginning of the tag)
        size_t   len;           //!< Length of the encoded item (tag + length + value)
} fr_der_encode_set_of_ptr_pairs_t;
 
/*
 *      Lexicographically sort the set of pairs
 */
static int CC_HINT(nonnull) fr_der_encode_set_of_cmp(void const *one, void const *two)
{
        fr_der_encode_set_of_ptr_pairs_t const *a = one;
        fr_der_encode_set_of_ptr_pairs_t const *b = two;
 
        if (a->len >= b->len) {
                return memcmp(a->data, b->data, a->len);
        }
 
        return memcmp(a->data, b->data, b->len);
}
 
static ssize_t fr_der_encode_set(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t            our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t            *vp;
        ssize_t               slen;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        fr_assert(fr_type_is_tlv(vp->vp_type));
 
        /*
         *      ISO/IEC 8825-1:2021
         *      8.11 Encoding of a set value
         *              8.11.1 The encoding of a set value shall be constructed.
         *              8.11.2 The contents octets shall consist of the complete encoding of one data value from each
         *                     of the types listed in the ASN.1 definition of the set type, in an order chosen by the
         *                     sender, unless the type was referenced with the keyword OPTIONAL or the keyword DEFAULT.
         *              8.11.3 The encoding of a data value may, but need not, be present for a type referenced with the
         *                     keyword OPTIONAL or the keyword DEFAULT.
         *
         *      11.5 Set and sequence components with default value
         *              The encoding of a set value or sequence value shall not include an encoding for any component
         *              value which is equal to its default value.
         *
         *      ISO/IEC 8825-1:2021
         *      8.12 Encoding of a set-of value
         *              8.12.1 The encoding of a set-of value shall be constructed.
         *              8.12.2 The text of 8.10.2 applies.
         *              8.12.3 The order of data values need not be preserved by the encoding and subsequent decoding.
         *
         *      11.6 Set-of components
         *              The encodings of the component values of a set-of value shall appear in ascending order, the
         *              encodings being compared as octet strings with the shorter components being padded at their
         *              trailing end with 0-octets.
         *                      NOTE - The padding octets are for comparison purposes only and do not appear in the
         *                      encodings.
         */
 
        if (fr_der_flag_is_set_of(vp->da)) {
                /*
                 *      Set-of items will all have the same tag, so we need to sort them lexicographically
                 */
                size_t                            i, count;
                fr_dbuff_t                        work_dbuff;
                fr_der_encode_set_of_ptr_pairs_t *ptr_pairs;
                uint8_t                          *buff;
                fr_da_stack_t                     da_stack;
                fr_dcursor_t                      child_cursor;
 
                /*
                 *      This can happen, but is possible.
                 */
                count = fr_pair_list_num_elements(&vp->children);
                if (unlikely(!count)) return 0;
 
                /*
                 *      Sets can be nested, so we have to use local buffers when sorting.
                 */
                buff = talloc_array(encode_ctx->tmp_ctx, uint8_t, fr_dbuff_remaining(&our_dbuff));
                fr_assert(buff != NULL);
 
                ptr_pairs = talloc_array(buff, fr_der_encode_set_of_ptr_pairs_t, count);
                if (unlikely(ptr_pairs == NULL)) {
                        fr_strerror_const("Failed to allocate memory for set of pointers");
                        talloc_free(buff);
                        return -1;
                }
 
                /*
                 *      Now that we have our intermediate buffers, initialize the buffers and start encoding.
                 */
                fr_dbuff_init(&work_dbuff, buff, fr_dbuff_remaining(&our_dbuff));
 
                fr_proto_da_stack_build(&da_stack, vp->da);
 
                FR_PROTO_STACK_PRINT(&da_stack, vp->da->depth - 1);
 
                fr_pair_dcursor_child_iter_init(&child_cursor, &vp->children, cursor);
 
                for (i = 0; fr_dcursor_current(&child_cursor) != NULL; i++) {
                        ptr_pairs[i].data = fr_dbuff_current(&work_dbuff);
 
                        slen = encode_value(&work_dbuff, &child_cursor, encode_ctx);
                        if (unlikely(slen < 0)) {
                                fr_strerror_printf("Failed to encode pair: %s", fr_strerror());
                                talloc_free(buff);
                                return slen;
                        }
 
                        ptr_pairs[i].len = slen;
                }
 
                fr_assert(i <= count);
                count = i;
 
                /*
                 *      If there's a "min" for this set, then we can't do anything about it.
                 */
                if (unlikely(!count)) goto done;
 
                /*
                 *      If there's only one child, we don't need to sort it.
                 */
                if (count > 1) qsort(ptr_pairs, count, sizeof(fr_der_encode_set_of_ptr_pairs_t), fr_der_encode_set_of_cmp);
 
                /*
                 *      The data in work_dbuff is always less than the data in the our_dbuff, so we don't need
                 *      to check the return value here.
                 */
                for (i = 0; i < count; i++) {
                        (void) fr_dbuff_in_memcpy(&our_dbuff, ptr_pairs[i].data, ptr_pairs[i].len);
                }
 
        done:
                talloc_free(buff);
 
                return fr_dbuff_set(dbuff, &our_dbuff);
        }
 
        /*
         *      Children of a set are ordered by tag.  However, as each tag can only be used once, this is a
         *      unique order.
         */
        fr_pair_list_sort(&vp->children, fr_der_pair_cmp_by_da_tag);
 
        return fr_der_encode_choice(dbuff, cursor, encode_ctx);
}
 
static ssize_t fr_der_encode_utc_time(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, UNUSED fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t       our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t const *vp;
        fr_sbuff_t       time_sbuff;
        char             fmt_time[50] = { 0 };
        size_t           i;
 
        fmt_time[0] = '\0';
        time_sbuff  = FR_SBUFF_OUT(fmt_time, sizeof(fmt_time));
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        /*
         *      ISO/IEC 8825-1:2021
         *      8.25 Encoding for values of the useful types
         *              The following "useful types" shall be encoded as if they had been replaced by their definitions
         *              given in clauses 46-48 of Rec. ITU-T X.680 | ISO/IEC 8824-1:
         *                      - generalized time;
         *                      - universal time;
         *                      - object descriptor.
         *
         *      8.26 Encoding for values of the TIME type and the useful time types
         *              8.26 Encoding for values of the TIME type and the useful time types 8.26.1 Encoding for values
         *              of the TIME type NOTE - The defined time types are subtypes of the TIME type, with the same
         *              tag, and have the same encoding as the TIME type. 8.26.1.1 The encoding of the TIME type shall
         *              be primitive. 8.26.1.2 The contents octets shall be the UTF-8 encoding of the value notation,
         *              after the removal of initial and final QUOTATION MARK (34) characters.
         *
         *      11.8 UTCTime
         *              11.8.1 The encoding shall terminate with "Z", as described in the ITU-T X.680 | ISO/IEC 8824-1
         *                     clause on UTCTime.
         *              11.8.2 The seconds element shall always be present.
         *              11.8.3 Midnight (GMT) shall be represented as "YYMMDD000000Z", where "YYMMDD" represents the
         *                     day following the midnight in question.
         */
 
        /*
         *      The format of a UTC time is "YYMMDDhhmmssZ"
         *      Where:
         *      1. YY is the year
         *      2. MM is the month
         *      3. DD is the day
         *      4. hh is the hour
         *      5. mm is the minute
         *      6. ss is the second (not optional in DER)
         *      7. Z is the timezone (UTC)
         */
        fr_unix_time_to_str(&time_sbuff, vp->vp_date, FR_TIME_RES_SEC, true);
 
        /*
         *      Remove the century from the year
         */
        fr_sbuff_shift(&time_sbuff, 2);
 
        /*
         *      Trim the time string of any unwanted characters
         */
        for (i = 0; i < sizeof(fmt_time); i++) {
                if (fmt_time[i] == '\0') {
                        break;
                }
 
                if ((fmt_time[i] == '-') || (fmt_time[i] == 'T') || (fmt_time[i] == ':')) {
                        size_t j = i;
 
                        while (fmt_time[j] != '\0') {
                                fmt_time[j] = fmt_time[j + 1];
                                j++;
                        }
 
                        fmt_time[j] = '\0';
 
                        continue;
                }
        }
 
        FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, fmt_time, DER_UTC_TIME_LEN);
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
static ssize_t fr_der_encode_generalized_time(fr_dbuff_t *dbuff, fr_dcursor_t *cursor,
                                              UNUSED fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t       our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t const *vp;
        fr_sbuff_t       time_sbuff;
        char             fmt_time[50] = { 0 };
        size_t           i;
 
        fmt_time[0] = '\0';
        time_sbuff  = FR_SBUFF_OUT(fmt_time, sizeof(fmt_time));
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        /*
         *      ISO/IEC 8825-1:2021
         *      8.25 Encoding for values of the useful types
         *              The following "useful types" shall be encoded as if they had been replaced by their definitions
         *              given in clauses 46-48 of Rec. ITU-T X.680 | ISO/IEC 8824-1:
         *                      - generalized time;
         *                      - universal time;
         *                      - object descriptor.
         *
         *      8.26 Encoding for values of the TIME type and the useful time types
         *              8.26 Encoding for values of the TIME type and the useful time types 8.26.1 Encoding for values
         *              of the TIME type NOTE - The defined time types are subtypes of the TIME type, with the same
         *              tag, and have the same encoding as the TIME type. 8.26.1.1 The encoding of the TIME type shall
         *              be primitive. 8.26.1.2 The contents octets shall be the UTF-8 encoding of the value notation,
         *              after the removal of initial and final QUOTATION MARK (34) characters.
         *
         *      11.7 GeneralizedTime
         *              11.7.1 The encoding shall terminate with a "Z", as described in the Rec. ITU-T X.680 | ISO/IEC
         *                     8824-1 clause on GeneralizedTime.
         *              11.7.2 The seconds element shall always be present.
         *              11.7.3 The fractional-seconds elements, if present, shall omit all trailing zeros; if the
         *                     elements correspond to 0, they shall be wholly omitted, and the decimal point element
         *                     also shall be omitted.
         */
 
        /*
         *      The format of a generalized time is "YYYYMMDDHHMMSS[.fff]Z"
         *      Where:
         *      1. YYYY is the year
         *      2. MM is the month
         *      3. DD is the day
         *      4. HH is the hour
         *      5. MM is the minute
         *      6. SS is the second
         *      7. fff is the fraction of a second (optional)
         *      8. Z is the timezone (UTC)
         */
 
        fr_unix_time_to_str(&time_sbuff, vp->vp_date, FR_TIME_RES_USEC, true);
 
        /*
         *      Trim the time string of any unwanted characters
         */
        for (i = 0; i < sizeof(fmt_time); i++) {
                if (fmt_time[i] == '\0') {
                        break;
                }
 
                if ((fmt_time[i] == '-') || (fmt_time[i] == 'T') || (fmt_time[i] == ':')) {
                        size_t j = i;
 
                        while (fmt_time[j] != '\0') {
                                fmt_time[j] = fmt_time[j + 1];
                                j++;
                        }
 
                        fmt_time[j] = '\0';
 
                        continue;
                }
 
                if (fmt_time[i] == '.') {
                        /*
                         *      Remove any trailing zeros
                         */
                        size_t j = strlen(fmt_time) - 2;
 
                        while (fmt_time[j] == '0') {
                                fmt_time[j]     = fmt_time[j + 1];
                                fmt_time[j + 1] = '\0';
                                j--;
                        }
 
                        /*
                         *      Remove the decimal point if there are no fractional seconds
                         */
                        if (j == i) {
                                fmt_time[i]     = fmt_time[i + 1];
                                fmt_time[i + 1] = '\0';
                        }
                }
        }
 
        FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, fmt_time, i);
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
/** Encode a CHOICE type
 *
 * @param[in] dbuff             Buffer to write the encoded data to
 * @param[in] cursor            Cursor to the pair to encode
 * @param[in] encode_ctx        Encoding context
 *
 * @return      Number of bytes written to the buffer, or -1 on error
 */
static ssize_t fr_der_encode_choice(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t            our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t const *vp;
        fr_da_stack_t         da_stack;
        fr_dcursor_t          child_cursor;
        ssize_t          slen = 0;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        fr_proto_da_stack_build(&da_stack, vp->da);
 
        FR_PROTO_STACK_PRINT(&da_stack, vp->da->depth - 1);
 
        fr_pair_dcursor_child_iter_init(&child_cursor, &vp->children, cursor);
 
        slen = fr_pair_cursor_to_network(&our_dbuff, &da_stack, vp->da->depth - 1, &child_cursor, encode_ctx, encode_pair);
        if (slen < 0) return -1;
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
static ssize_t fr_der_encode_X509_extensions(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t        our_dbuff = FR_DBUFF(dbuff);
        fr_dbuff_marker_t outer_seq_len_start;
        fr_dcursor_t      child_cursor, root_cursor, parent_cursor;
        fr_pair_t const  *vp;
        ssize_t           slen        = 0;
        size_t            is_critical = 0;
        uint64_t          max, num;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        fr_assert(fr_type_is_group(vp->vp_type));
 
        /*
         *      RFC 5280 Section 4.2
         *      The extensions defined for X.509 v3 certificates provide methods for
         *      associating additional attributes with users or public keys and for
         *      managing relationships between CAs.  The X.509 v3 certificate format
         *      also allows communities to define private extensions to carry
         *      information unique to those communities.  Each extension in a
         *      certificate is designated as either critical or non-critical.
         *
         *      Each extension includes an OID and an ASN.1 structure.  When an
         *      extension appears in a certificate, the OID appears as the field
         *      extnID and the corresponding ASN.1 DER encoded structure is the value
         *      of the octet string extnValue.
         *
         *      RFC 5280 Section A.1 Explicitly Tagged Module, 1988 Syntax
         *              Extensions  ::=  SEQUENCE SIZE (1..MAX) OF Extension
         *
         *              Extension  ::=  SEQUENCE  {
         *                      extnID      OBJECT IDENTIFIER,
         *                      critical    BOOLEAN DEFAULT FALSE,
         *                      extnValue   OCTET STRING
         *                                      -- contains the DER encoding of an ASN.1 value
         *                                      -- corresponding to the extension type identified
         *                                      -- by extnID
         *              }
         *
         *      So the extensions are a SEQUENCE of SEQUENCEs containing an OID, a boolean and an OCTET STRING.
         *      Note: If the boolean value is false, it is not included in the encoding.
         */
 
        max = fr_der_flag_max(vp->da); /* Maximum number of extensions specified in the dictionary */
        num = 0;
 
        slen = fr_der_encode_tag(&our_dbuff, FR_DER_TAG_SEQUENCE, FR_DER_CLASS_UNIVERSAL, FR_DER_TAG_CONSTRUCTED);
        if (slen < 0) return slen;
 
        fr_dbuff_marker(&outer_seq_len_start, &our_dbuff);
        FR_DBUFF_ADVANCE_RETURN(&our_dbuff, 1);
 
        FR_PROTO_HEX_DUMP(fr_dbuff_start(&our_dbuff), fr_dbuff_used(&our_dbuff),"BEFORE encoded X509 extension");
 
        fr_pair_dcursor_child_iter_init(&root_cursor, &vp->children, cursor);
        fr_dcursor_copy(&parent_cursor, &root_cursor);
 
        while (fr_dcursor_current(&parent_cursor)) {
                uint64_t          component;
                int               count;
                fr_dbuff_marker_t length_start, inner_seq_len_start;
                fr_pair_t         *child;
 
                /*
                 *      Extensions are sequences or sets containing 2 items:
                 *      1. The first item is the OID
                 *      2. The second item is the value
                 *
                 *      Note: The value may be a constructed or primitive type
                 */
 
                if (num >= max) {
                        fr_strerror_printf("Too many X509 extensions (%" PRIu64 ")", max);
                        break;
                }
 
                slen = fr_der_encode_tag(&our_dbuff, FR_DER_TAG_SEQUENCE, FR_DER_CLASS_UNIVERSAL, FR_DER_TAG_CONSTRUCTED);
                if (slen < 0) return slen;
 
                fr_dbuff_marker(&inner_seq_len_start, &our_dbuff);
                FR_DBUFF_ADVANCE_RETURN(&our_dbuff, 1);
 
                /*
                 *      Encode the OID portion of the extension
                 */
                slen = fr_der_encode_tag(&our_dbuff, FR_DER_TAG_OID, FR_DER_CLASS_UNIVERSAL, FR_DER_TAG_PRIMITIVE);
                if (slen < 0) return slen;
 
                fr_dbuff_marker(&length_start, &our_dbuff);
                FR_DBUFF_ADVANCE_RETURN(&our_dbuff, 1);
 
                /*
                 *      Walk through the children until we find either an attribute marked as an extension, or one with
                 *      no children (which is an unknown OID).
                 *
                 *      We will use this to construct the OID to encode, as well as to get the actual value of the
                 *      extension.
                 */
                fr_dcursor_copy(&child_cursor, &parent_cursor);
                count = 0;
 
                while ((child = fr_dcursor_current(&child_cursor)) != NULL) {
                        PAIR_VERIFY(child);
 
                        FR_PROTO_TRACE("Child: %s", child->da->name);
 
                        if (!is_critical && (strcmp(child->da->name, "Critical") == 0)) {
                                /*
                                 *      We don't encode the critical flag
                                 */
                                is_critical = fr_pair_list_num_elements(&child->children);
                                FR_PROTO_TRACE("Critical flag: %zu", is_critical);
 
                                fr_pair_dcursor_child_iter_init(&parent_cursor, &child->children, &child_cursor);
                                goto next;
                        }
 
                        /*
                         *      If we find a normal leaf data type, we don't encode it.  But we do encode leaf data
                         *      types which are marked up as needing OID leaf encoding.
                         */
                        if (!fr_type_is_structural(child->vp_type) && !fr_der_flag_is_oid_leaf(child->da) && !child->da->flags.is_raw) {
                                FR_PROTO_TRACE("Found non-structural child %s", child->da->name);
 
                                fr_dcursor_copy(&child_cursor, &parent_cursor);
                                break;
                        }
 
                        slen = fr_der_encode_oid_from_value(&our_dbuff, child->da->attr, &component, &count);
                        if (unlikely(slen < 0)) return -1;
 
                        /*
                         *      We've encoded a leaf data type, or a raw one.  Stop encoding it.
                         */
                        if (!fr_type_is_structural(child->vp_type)) break;
 
                        /*
                         *      Unless this was the last child (marked as an extension), there should only be one child
                         *      - representing the next OID in the extension
                         */
                        if (fr_pair_list_num_elements(&child->children) > 1) break;
 
                next:
                        if (fr_der_flag_is_oid_leaf(child->da)) break;
 
                        fr_pair_dcursor_child_iter_init(&child_cursor, &child->children, &child_cursor);
                }
 
                /*
                 *      Encode the length of the OID
                 */
                slen = fr_der_encode_len(&our_dbuff, &length_start);
                if (slen < 0) return slen;
 
                /*
                 *      Encode the critical flag
                 */
                if (is_critical) {
                        /*
                         *      Universal+Boolean flag is always 0x01. Length of a boolean is always 0x01.
                         *      True is always 0xff.
                         */
                        FR_DBUFF_IN_BYTES_RETURN(&our_dbuff, (uint8_t) 0x01, (uint8_t) 0x01, (uint8_t)(0xff));
                        is_critical--;
                }
 
                /*
                 *      Encode the value portion of the extension
                 */
                slen = fr_der_encode_tag(&our_dbuff, FR_DER_TAG_OCTETSTRING, FR_DER_CLASS_UNIVERSAL, FR_DER_TAG_PRIMITIVE);
                if (slen < 0) return slen;
 
                fr_dbuff_marker(&length_start, &our_dbuff);
                FR_DBUFF_ADVANCE_RETURN(&our_dbuff, 1);
 
                /*
                 *      Encode the data
                 */
                slen = encode_value(&our_dbuff, &child_cursor, encode_ctx);
                if (slen < 0) return slen;
 
                /*
                 *      Encode the length of the value
                 */
                slen = fr_der_encode_len(&our_dbuff, &length_start);
                if (slen < 0) return slen;
 
                /*
                 *      Encode the length of the extension (OID + Value portions)
                 */
                slen = fr_der_encode_len(&our_dbuff, &inner_seq_len_start);
                if (slen < 0) return -1;
 
                if (is_critical) {
                        fr_dcursor_next(&parent_cursor);
                        num++;
                        continue;
                }
 
                FR_PROTO_HEX_DUMP(fr_dbuff_start(&our_dbuff), fr_dbuff_behind(&outer_seq_len_start) + 2,
                                  "Encoded X509 extension");
 
                fr_dcursor_next(&root_cursor);
                fr_dcursor_copy(&parent_cursor, &root_cursor);
                num++;
        }
 
        /*
         *      Encode the length of the extensions
         */
        slen = fr_der_encode_len(&our_dbuff, &outer_seq_len_start);
        if (slen < 0) return slen;
 
        FR_PROTO_HEX_DUMP(fr_dbuff_start(&our_dbuff), slen, "Encoded X509 extensions");
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
static ssize_t fr_der_encode_oid_and_value(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t        our_dbuff = FR_DBUFF(dbuff);
        fr_dbuff_marker_t length_start;
        fr_dcursor_t      child_cursor, parent_cursor = *cursor;
        fr_pair_t const   *vp, *child;
        ssize_t           slen   = 0;
        uint64_t          component;
        int               count;
 
        vp = fr_dcursor_current(&parent_cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        fr_assert(fr_type_is_group(vp->vp_type));
 
        /*
         *      A very common pattern in DER encoding is ro have a sequence of set containing two things: an OID and a
         *      value, where the OID is used to determine how to decode the value.
         *      We will be decoding the OID first and then try to find the attribute associated with that OID to then
         *      decode the value. If no attribute is found, one will be created and the value will be stored as raw
         *      octets in the attribute.
         *
         *      Note: The value may be a constructed or primitive type
         */
 
        slen = fr_der_encode_tag(&our_dbuff, FR_DER_TAG_OID, FR_DER_CLASS_UNIVERSAL, FR_DER_TAG_PRIMITIVE);
        if (slen < 0) return slen;
 
        fr_dbuff_marker(&length_start, &our_dbuff);
        FR_DBUFF_ADVANCE_RETURN(&our_dbuff, 1);
 
        /*
         *      Walk through the children until we find either an attribute marked as an oid leaf, or one with
         *      no children (which is an unknown OID).
         *
         *      We will use this to construct the OID to encode, as well as to get the actual value of the
         *      pair.
         */
        fr_pair_dcursor_child_iter_init(&child_cursor, &vp->children, &parent_cursor);
        count = 0;
 
        while ((child = fr_dcursor_current(&child_cursor)) != NULL) {
                PAIR_VERIFY(child);
 
                /*
                 *      If we find a normal leaf data type, we don't encode it.  But we do encode leaf data
                 *      types which are marked up as needing OID leaf encoding.
                 */
                if (!fr_type_is_structural(child->vp_type) && !fr_der_flag_is_oid_leaf(child->da) && !child->da->flags.is_raw) {
                        FR_PROTO_TRACE("Found non-structural child %s", child->da->name);
 
                        fr_dcursor_copy(&child_cursor, &parent_cursor);
                        break;
                }
 
                slen = fr_der_encode_oid_from_value(&our_dbuff, child->da->attr, &component, &count);
                if (unlikely(slen < 0)) return -1;
 
                /*
                 *      We've encoded a leaf data type, or a raw one.  Stop encoding it.
                 */
                if (!fr_type_is_structural(child->vp_type)) break;
 
                /*
                 *      Some structural types can be marked as a leaf for the purposes of OID encoding.
                 */
                if (fr_der_flag_is_oid_leaf(child->da)) break;
 
                /*
                 *      Unless this was the last child (marked as an oid leaf), there should only be one child
                 *      - representing the next OID in the pair
                 */
                if (fr_pair_list_num_elements(&child->children) > 1) break;
 
                fr_pair_dcursor_child_iter_init(&child_cursor, &child->children, &child_cursor);
        }
 
        /*
         *      Encode the length of the OID
         */
        slen = fr_der_encode_len(&our_dbuff, &length_start);
        if (slen < 0) return slen;
 
        /*
         *      And then encode the actual data.
         */
        slen = encode_value(&our_dbuff, &child_cursor, encode_ctx);
        if (slen < 0) return slen;
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
static ssize_t fr_der_encode_string(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, UNUSED fr_der_encode_ctx_t *encode_ctx)
{
        fr_dbuff_t       our_dbuff = FR_DBUFF(dbuff);
        fr_pair_t const *vp;
 
        vp = fr_dcursor_current(cursor);
        PAIR_VERIFY(vp);
        fr_assert(!vp->da->flags.is_raw);
 
        /*
         *      ISO/IEC 8825-1:2021
         *      8.23 Encoding for values of the restricted character string types
         *              8.23.1 The data value consists of a string of characters from the character set specified in
         *                      the ASN.1 type definition.
         *              8.23.2 Each data value shall be encoded independently of other data values of the same type.
         *
         *      10.2 String encoding forms
         *              For bitstring, octetstring and restricted character string types, the constructed form of
         *              encoding shall not be used. (Contrast with 8.23.6.)
         *
         *      NOTE:
         *              We DO NOT check for restricted character sets here. This should be done as a separate validation
         *              step. Here we simply trust that administrators have done their job and are providing us with
         *              valid data.
         */
 
        FR_DBUFF_IN_MEMCPY_RETURN(&our_dbuff, vp->vp_strvalue, vp->vp_length);
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
static const fr_der_tag_encode_t tag_funcs[FR_DER_TAG_MAX] = {
        [FR_DER_TAG_BOOLEAN]          = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_boolean },
        [FR_DER_TAG_INTEGER]          = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_integer },
        [FR_DER_TAG_BITSTRING]        = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_bitstring },
        [FR_DER_TAG_OCTETSTRING]      = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_octetstring },
        [FR_DER_TAG_NULL]             = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_null },
        [FR_DER_TAG_OID]              = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_oid },
        [FR_DER_TAG_ENUMERATED]       = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_enumerated },
        [FR_DER_TAG_UTF8_STRING]      = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_string },
        [FR_DER_TAG_SEQUENCE]         = { .constructed = FR_DER_TAG_CONSTRUCTED, .encode = fr_der_encode_sequence },
        [FR_DER_TAG_SET]              = { .constructed = FR_DER_TAG_CONSTRUCTED, .encode = fr_der_encode_set },
        [FR_DER_TAG_PRINTABLE_STRING] = { .constructed = FR_DER_TAG_PRIMITIVE,
                                          .encode      = fr_der_encode_string },
        [FR_DER_TAG_T61_STRING]       = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_string },
        [FR_DER_TAG_IA5_STRING]       = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_string },
        [FR_DER_TAG_UTC_TIME]         = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_utc_time },
        [FR_DER_TAG_GENERALIZED_TIME] = { .constructed = FR_DER_TAG_PRIMITIVE,
                                          .encode      = fr_der_encode_generalized_time },
        [FR_DER_TAG_VISIBLE_STRING]   = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_string },
        [FR_DER_TAG_GENERAL_STRING]   = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_string },
        [FR_DER_TAG_UNIVERSAL_STRING] = { .constructed = FR_DER_TAG_PRIMITIVE,
                                          .encode      = fr_der_encode_string },
};
 
static const fr_der_tag_encode_t type_funcs[FR_TYPE_MAX] = {
        [FR_TYPE_IPV4_ADDR]       = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_ipv4_addr },
        [FR_TYPE_IPV4_PREFIX]     = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_ipv4_prefix },
        [FR_TYPE_IPV6_ADDR]       = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_ipv6_addr },
        [FR_TYPE_IPV6_PREFIX]     = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_ipv6_prefix },
 
        [FR_TYPE_COMBO_IP_ADDR]   = { .constructed = FR_DER_TAG_PRIMITIVE, .encode = fr_der_encode_combo_ip },
};
 
 
/** Encode the length field of a DER structure
 *
 *  The input dbuff is composed of the following data:
 *
 *      1 byte of nothing (length_start).  Where the "length length" will be written to.
 *      N bytes of data.  dbuff is pointing to the end of the encoded data.
 *
 *  We have to either write a length to length_start (if it's < 0x7f),
 *
 *  OR we figure out how many bytes we need to encode the length,
 *  shift the data to the right to make room, and then encode the
 *  length.
 *
 * @param dbuff         The buffer to update with the length field
 * @param length_start  The start of the length field
 * @return
 *      - <0 for "cannot extend the input buffer by the needed "length length".
 *      - 1 for "success".  Note that 'length_start' WILL be updated after this call,
 *        and the caller should just release it immediately.
 */
static ssize_t fr_der_encode_len(fr_dbuff_t *dbuff, fr_dbuff_marker_t *length_start)
{
        size_t            i, len_len;
        size_t            tmp, datalen;
 
        datalen = fr_dbuff_current(dbuff) - fr_dbuff_current(length_start) - 1;
 
        /*
         *      If the length can fit in a single byte, we don't need to extend the size of the length field
         */
        if (datalen <= 0x7f) {
                (void) fr_dbuff_in(length_start, (uint8_t) datalen);
                return 1;
        }
 
        /*
         *      Calculate the number of bytes needed to encode the length.
         */
        for (tmp = datalen, len_len = 0; tmp != 0; tmp >>= 8) {
                len_len++;
        }
 
        /*
         *      DER says that the length field cannot be more than
         *      0x7f.  Since sizeof(datalen) == 8, we can always
         *      encode the length field.
         */
        fr_assert(len_len > 0);
        fr_assert(len_len < 0x7f);
 
        (void) fr_dbuff_in(length_start, (uint8_t) (0x80 | len_len));
 
        /*
         *      This is the only operation which can fail.  The dbuff
         *      is currently set to the end of the encoded data.  We
         *      need to ensure that there is sufficient room in the
         *      dbuff to encode the additional bytes.
         *
         *      fr_dbuff_set() checks if the length exceeds the input
         *      buffer.  But it does NOT extend the buffer by reading
         *      more data, if more data is needed.  So we need to
         *      manually extend the dbuff here.
         */
        FR_DBUFF_EXTEND_LOWAT_OR_RETURN(dbuff, len_len);
 
        /*
         *      Reset the dbuff to the new start, where the data
         *      should be.
         */
        fr_dbuff_set(dbuff, fr_dbuff_current(length_start) + len_len);
 
        /*
         *      Move the data over.  Note that the move updates BOTH
         *      input and output dbuffs.  As a result, we have to wrap
         *      'length_start' in a temporary dbuff, so that it
         *      doesn't get updated by the move.
         */
        fr_dbuff_move(dbuff, &FR_DBUFF(length_start), datalen);
 
        /*
         *      Encode high bits first, but only the non-zero ones.
         */
        for (i = len_len; i > 0; i--) {
                (void) fr_dbuff_in(length_start, (uint8_t)((datalen) >> ((i - 1) * 8)));
        }
 
        return 1;
}
 
/** Encode a DER tag
 *
 * @param dbuff         The buffer to write the tag to
 * @param tag_num       The tag number
 * @param tag_class     The tag class
 * @param constructed   Whether the tag is constructed
 *
 * @return              The number of bytes written to the buffer
 */
static inline CC_HINT(always_inline) ssize_t
        fr_der_encode_tag(fr_dbuff_t *dbuff, fr_der_tag_t tag_num, fr_der_tag_class_t tag_class,
                          fr_der_tag_constructed_t constructed)
{
        fr_dbuff_t      our_dbuff = FR_DBUFF(dbuff);
        uint8_t         tag_byte;
 
        tag_byte = (tag_class & DER_TAG_CLASS_MASK) | (constructed & DER_TAG_CONSTRUCTED_MASK) |
                   (tag_num & DER_TAG_NUM_MASK);
 
        FR_DBUFF_IN_RETURN(&our_dbuff, tag_byte);
 
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
/** Encode a DER structure
 *
 * @param[out] dbuff            The buffer to write the structure to
 * @param[in] cursor    The cursor to the structure to encode
 * @param[in] encode_ctx        The encoding context
 *
 * @return              The number of bytes written to the buffer
 */
static ssize_t encode_value(fr_dbuff_t *dbuff, fr_dcursor_t *cursor, void *encode_ctx)
{
        fr_pair_t const     *vp;
        fr_dbuff_t           our_dbuff;
        fr_dbuff_marker_t    marker;
        fr_der_tag_encode_t const *func;
        fr_der_tag_t         tag;
        fr_der_tag_class_t   tag_class;
        fr_der_encode_ctx_t *uctx = encode_ctx;
        ssize_t              slen = 0;
        fr_der_attr_flags_t const *flags;
 
        if (unlikely(cursor == NULL)) {
                fr_strerror_const("No cursor to encode");
                return -1;
        }
 
        vp = fr_dcursor_current(cursor);
        if (unlikely(!vp)) {
                fr_strerror_const("No pair to encode");
                return -1;
        }
 
        PAIR_VERIFY(vp);
 
        FR_PROTO_TRACE("Encoding %s", vp->da->name);
 
        flags = fr_der_attr_flags(vp->da);
        fr_assert(flags != NULL);
 
        /*
         *      Raw things get encoded as-is, so that we can encode the correct tag and class.
         */
        if (unlikely(vp->da->flags.is_raw)) {
                fr_assert(vp->vp_type == FR_TYPE_OCTETS);
 
                slen = fr_der_encode_octetstring(dbuff, cursor, encode_ctx);
                if (slen < 0) return 0;
 
                fr_dcursor_next(cursor);
                return slen;
        }
 
        our_dbuff = FR_DBUFF(dbuff);
 
        /*
         *      ISO/IEC 8825-1:2021
         *      The structure of a DER encoding is as follows:
         *
         *              +------------+--------+-------+
         *              | IDENTIFIER | LENGTH | VALUE |
         *              +------------+--------+-------+
         *
         *      The IDENTIFIER is a tag that specifies the type of the value field and is encoded as follows:
         *
         *                8   7    6    5   4   3   2   1
         *              +---+---+-----+---+---+---+---+---+
         *              | Class | P/C |     Tag Number    |
         *              +---+---+-----+---+---+---+---+---+
         *                         |
         *                         |- 0 = Primitive
         *                         |- 1 = Constructed
         *
         *      The CLASS field specifies the encoding class of the tag and may be one of the following values:
         *
         *              +------------------+-------+-------+
         *              |      Class       | Bit 8 | Bit 7 |
         *              +------------------+-------+-------+
         *              | UNIVERSAL        |   0   |   0   |
         *              | APPLICATION      |   0   |   1   |
         *              | CONTEXT-SPECIFIC |   1   |   0   |
         *              | PRIVATE          |   1   |   1   |
         *              +------------------+-------+-------+
         *
         *      The P/C field specifies whether the value field is primitive or constructed.
         *      The TAG NUMBER field specifies the tag number of the value field and is encoded as an unsigned binary
         *      integer.
         *
         *      The LENGTH field specifies the length of the VALUE field and is encoded as an unsigned binary integer
         *      and may be encoded as a single byte or multiple bytes.
         *
         *      The VALUE field contains LENGTH number of bytes and is encoded according to the tag.
         *
         */
 
        if (flags->has_default_value) {
                /*
                 *      Skip encoding the default value, as per ISO/IEC 8825-1:2021 11.5
                 */
                if (fr_value_box_cmp(&vp->data, flags->default_value) == 0) {
                        FR_PROTO_TRACE("Skipping default value");
                        fr_dcursor_next(cursor);
                        return 0;
                }
        }
 
        if (unlikely(flags->is_choice)) {
                slen = fr_der_encode_choice(&our_dbuff, cursor, uctx);
                if (slen < 0) return slen;
 
                fr_dcursor_next(cursor);
                return fr_dbuff_set(dbuff, &our_dbuff);
        }
 
        tag = flags->der_type;
        if (!tag) tag = fr_type_to_der_tag_default(vp->vp_type);
 
        if (unlikely(tag == FR_DER_TAG_INVALID)) {
                fr_strerror_printf("No tag defined for type %s", fr_type_to_str(vp->vp_type));
                return -1;
        }
 
        fr_assert(tag < FR_DER_TAG_MAX);
 
        func = &type_funcs[vp->vp_type];
        if (!func->encode) func = &tag_funcs[tag];
 
        fr_assert(func != NULL);
        fr_assert(func->encode != NULL);
 
        /*
         *      Default flag class is 0, which is FR_DER_CLASS_UNIVERSAL.
         */
        tag_class = flags->class;
 
        /*
         *      We call the DER type encoding function based on its
         *      tag, but we might need to encode an option value
         *      instead of a tag.
         */
        if (flags->is_option) tag = flags->option;
 
        slen = fr_der_encode_tag(&our_dbuff, tag, tag_class, func->constructed);
        if (slen < 0) return slen;
 
        /*
         *      Mark and reserve space in the buffer for the length field
         */
        fr_dbuff_marker(&marker, &our_dbuff);
        FR_DBUFF_ADVANCE_RETURN(&our_dbuff, 1);
 
        if (flags->is_extensions) {
                slen = fr_der_encode_X509_extensions(&our_dbuff, cursor, uctx);
        } else {
 
                slen = func->encode(&our_dbuff, cursor, uctx);
        }
        if (slen < 0) return slen;
 
        /*
        *       Encode the length of the value
        */
        slen = fr_der_encode_len(&our_dbuff, &marker);
        if (slen < 0) return slen;
 
        fr_dcursor_next(cursor);
        return fr_dbuff_set(dbuff, &our_dbuff);
}
 
static ssize_t fr_der_encode_proto(UNUSED TALLOC_CTX *ctx, fr_pair_list_t *vps, uint8_t *data, size_t data_len,
                                   void *encode_ctx)
{
        fr_dbuff_t   dbuff;
        fr_dcursor_t cursor;
        ssize_t      slen;
 
        fr_dbuff_init(&dbuff, data, data_len);
 
        fr_pair_dcursor_init(&cursor, vps);
 
        slen = encode_value(&dbuff, &cursor, encode_ctx);
 
        if (slen < 0) {
                fr_strerror_printf("Failed to encode data: %s", fr_strerror());
                return -1;
        }
 
        return slen;
}
 
/*
 *      Test points
 */
static int encode_test_ctx(void **out, TALLOC_CTX *ctx, UNUSED fr_dict_t const *dict)
{
        fr_der_encode_ctx_t *test_ctx;
 
        test_ctx = talloc_zero(ctx, fr_der_encode_ctx_t);
        if (!test_ctx) return -1;
 
        test_ctx->tmp_ctx            = talloc(test_ctx, uint8_t);
 
        *out = test_ctx;
 
        return 0;
}
 
extern fr_test_point_pair_encode_t der_tp_encode_pair;
fr_test_point_pair_encode_t        der_tp_encode_pair = {
               .test_ctx = encode_test_ctx,
               .func     = encode_value,
};
 
extern fr_test_point_proto_encode_t der_tp_encode_proto;
fr_test_point_proto_encode_t        der_tp_encode_proto = {
               .test_ctx = encode_test_ctx,
               .func     = fr_der_encode_proto,
};