cbor.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
 */
 
/** CBPR encoding and decoding
 *
 * @file src/lib/util/cbor.c
 *
 * @copyright 2024 Network RADIUS SAS (legal@networkradius.com)
 */
RCSID("$Id: b6543428c2956fb4e9f4655263f20aa521e9d8dc $")
 
#include <freeradius-devel/util/cbor.h>
 
#define CBOR_INTEGER    (0)
#define CBOR_NEGATIVE   (1)
#define CBOR_OCTETS     (2)
#define CBOR_STRING     (3)
#define CBOR_ARRAY      (4)
#define CBOR_MAP        (5)
#define CBOR_TAG        (6)
#define CBOR_FLOAT      (7)
 
#define CBOR_1_BYTE ((uint8_t) 24)
#define CBOR_2_BYTE ((uint8_t) 25)
#define CBOR_4_BYTE ((uint8_t) 26)
#define CBOR_8_BYTE ((uint8_t) 27)
 
static const char *cbor_type_to_str[8] = {
        "integer", "negative", "octets", "string",
        "array", "map", "tag", "float"
};
 
/*
 *      Some of our data types need tags.
 *
 *      We don't have a tag to data type array.  When decoding, we should usually have the enclosing pair
 *      number, which includes our data type.  If the tag type doesn't match the value here, then something is
 *      wrong.
 */
static const uint64_t cbor_type_to_tag[FR_TYPE_MAX + 1] = {
        [FR_TYPE_DATE] = 1,
        [FR_TYPE_ETHERNET] = 48,
        [FR_TYPE_IPV4_ADDR] = 52,
        [FR_TYPE_IPV4_PREFIX] = 52,
        [FR_TYPE_IPV6_ADDR] = 54,
        [FR_TYPE_IPV6_PREFIX] = 54,
        [FR_TYPE_TIME_DELTA] = 1002,
};
 
static fr_type_t cbor_guess_type(fr_dbuff_t *dbuff, bool pair);
 
static ssize_t cbor_encode_integer(fr_dbuff_t *dbuff, uint8_t type, uint64_t data)
{
        fr_dbuff_t      work_dbuff = FR_DBUFF(dbuff);
        uint8_t         value[8];
 
        fr_assert(type < 8);
        type <<= 5;
 
        if (data < 24) {
                data |= type;
 
                FR_DBUFF_IN_BYTES_RETURN(&work_dbuff, (uint8_t) (data & 0xff));
                goto done;
        }
 
        if (data < (((uint64_t) 1) << 8)) {
                value[0] = data;
 
                FR_DBUFF_IN_BYTES_RETURN(&work_dbuff, (uint8_t) (type | CBOR_1_BYTE));
                FR_DBUFF_IN_RETURN(&work_dbuff, value[0]);
                goto done;
        }
 
        if (data < (((uint64_t) 1) << 16)) {
                fr_nbo_from_uint16(value, data);
 
                FR_DBUFF_IN_BYTES_RETURN(&work_dbuff, (uint8_t) (type | CBOR_2_BYTE));
                FR_DBUFF_IN_MEMCPY_RETURN(&work_dbuff, value, 2);
                goto done;
        }
 
        if (data < (((uint64_t) 1) << 32)) {
                fr_nbo_from_uint32(value, data);
 
                FR_DBUFF_IN_BYTES_RETURN(&work_dbuff, (uint8_t) (type | CBOR_4_BYTE));
                FR_DBUFF_IN_MEMCPY_RETURN(&work_dbuff, value, 4);
                goto done;
        }
 
        fr_nbo_from_uint64(value, data);
 
        /*
         *      Has to be 8 bytes.
         */
        FR_DBUFF_IN_BYTES_RETURN(&work_dbuff, type | CBOR_8_BYTE);
        FR_DBUFF_IN_MEMCPY_RETURN(&work_dbuff, value, 8);
 
done:
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
#define cbor_encode_array(_dbuff, _size) cbor_encode_integer(_dbuff, CBOR_ARRAY, _size)
 
#define cbor_encode_tag(_dbuff, _tag) cbor_encode_integer(_dbuff, CBOR_TAG, _tag)
 
/*
 *      Make many things easier
 */
#define return_slen return slen - fr_dbuff_used(&work_dbuff)
 
/*
 *      Octets is length + data
 */
static ssize_t cbor_encode_octets(fr_dbuff_t *dbuff, uint8_t const *data, size_t data_len)
{
        fr_dbuff_t      work_dbuff = FR_DBUFF(dbuff);
        ssize_t slen;
 
        slen = cbor_encode_integer(&work_dbuff, CBOR_OCTETS, data_len);
        if (slen <= 0) return_slen;
 
        if (data_len > 0) FR_DBUFF_IN_MEMCPY_RETURN(&work_dbuff, data, data_len);
 
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
static ssize_t cbor_encode_int64(fr_dbuff_t *dbuff, int64_t neg)
{
        fr_dbuff_t      work_dbuff = FR_DBUFF(dbuff);
        ssize_t slen;
 
        if (neg >= 0) {
                slen = cbor_encode_integer(&work_dbuff, CBOR_INTEGER, neg);
        } else {
                uint64_t data;
 
                neg++;
                data = -neg;
                slen = cbor_encode_integer(&work_dbuff, CBOR_NEGATIVE, data);
        }
        if (slen <= 0) return_slen;
 
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
#define cbor_encode_key cbor_encode_int64
 
/** Encode CBOR
 *
 *  Values 0..23 can be encoded in place.  Other values can be encoded using the closest smallest integer
 */
ssize_t fr_cbor_encode_value_box(fr_dbuff_t *dbuff, fr_value_box_t *vb)
{
        fr_dbuff_t      work_dbuff = FR_DBUFF(dbuff);
        uint8_t         type = CBOR_INTEGER;
        uint64_t        data;
        int64_t         neg;
        ssize_t         slen;
        uint8_t         const *p, *end;
 
        switch (vb->type) {
        case FR_TYPE_BOOL:
                /*
                 *      One byte of FLOAT (i.e. special value), and the boolean as a "simple value".
                 */
                FR_DBUFF_IN_BYTES_RETURN(&work_dbuff, (uint8_t) ((CBOR_FLOAT << 5) | (20 + vb->vb_bool)));
                break;
 
        case FR_TYPE_UINT8:
                data = vb->vb_uint8;
                goto encode_int;
 
        case FR_TYPE_UINT16:
                data = vb->vb_uint16;
                goto encode_int;
 
        case FR_TYPE_UINT32:
                data = vb->vb_uint64;
                goto encode_int;
 
        case FR_TYPE_UINT64:
                data = vb->vb_uint64;
                goto encode_int;
 
        /*
         *      Negative numbers.
         */
        case FR_TYPE_INT8:
                neg = vb->vb_int8;
                goto encode_neg;
 
        case FR_TYPE_INT16:
                neg = vb->vb_int16;
                goto encode_neg;
 
        case FR_TYPE_INT32:
                neg = vb->vb_int64;
                goto encode_neg;
 
        case FR_TYPE_INT64:
                neg = vb->vb_int64;
        encode_neg:
                if (neg >= 0) {
                        type = CBOR_NEGATIVE;
                        data = neg;
                        goto encode_int;
                }
 
                /*
                 *      convert -1..-2^63 to 0..-(2^63-1)
                 *      and then it fits into a positive integer.
                 */
                neg++;
                data = -neg;
 
        encode_int:
                return cbor_encode_integer(dbuff, type, data);
 
        case FR_TYPE_OCTETS:
                return cbor_encode_octets(dbuff, vb->vb_octets, vb->vb_length);
 
        case FR_TYPE_STRING:
                slen = cbor_encode_integer(&work_dbuff, CBOR_STRING, vb->vb_length);
                if (slen <= 0) return_slen;
 
                if (vb->vb_length) FR_DBUFF_IN_MEMCPY_RETURN(&work_dbuff, vb->vb_strvalue, vb->vb_length);
                break;
 
                /*
                 *      More complex data types are represented by type "tag", followed by a tag number.  The
                 *      actual data is then encoded as the next item after the tag.
                 */
        case FR_TYPE_ETHERNET:
                slen = cbor_encode_tag(&work_dbuff, cbor_type_to_tag[vb->type]);
                if (slen <= 0) return_slen;
 
                slen = cbor_encode_octets(&work_dbuff, vb->vb_ether, sizeof(vb->vb_ether));
                if (slen <= 0) return_slen;
                break;
 
                /*
                 *      Tag 1, with integer seconds since epoch.
                 *
                 *      @todo - if the input has time resolution, then save it in that format.
                 *
                 *      RFC 9581 Section 3.
                 *
                 *      A tag with key 1001, and then: a map with required key 1 (integer epoch seconds) and
                 *      optional key -3 (milliseconds), -6 (microseconds), or -9 (integer nanoseconds).
                 *
                 *      For the encoder, there are a ton of different formats for dates, and we shouldn't
                 *      bother to parse them all. :(
                 */
        case FR_TYPE_DATE:
                slen = cbor_encode_tag(&work_dbuff, cbor_type_to_tag[vb->type]);
                if (slen <= 0) return_slen;
 
                neg = fr_unix_time_to_sec(vb->vb_date);
                slen = cbor_encode_int64(&work_dbuff, neg);
                if (slen <= 0) return_slen;
                break;
 
                /*
                 *      RFC 9581 Section 4.
                 *
                 *      A tag with key 1002, and then: a map with required key 1 (integer seconds) and
                 *      optional key -3 (milliseconds), -6 (microseconds), or -9 (integer nanoseconds).
                 */
        case FR_TYPE_TIME_DELTA:
                slen = cbor_encode_tag(&work_dbuff, cbor_type_to_tag[vb->type]);
                if (slen <= 0) return_slen;
 
                neg = fr_time_delta_unwrap(vb->vb_time_delta) % NSEC;
 
                slen = cbor_encode_integer(&work_dbuff, CBOR_MAP, 1 + (neg != 0));
                if (slen <= 0) return_slen;
 
                /*
                 *      1: seconds
                 */
                slen = cbor_encode_key(&work_dbuff, 1);
                if (slen <= 0) return_slen;
 
                slen = cbor_encode_int64(&work_dbuff, fr_time_delta_to_sec(vb->vb_time_delta));
                if (slen <= 0) return_slen;
 
                /*
                 *      -9: nanoseconds
                 */
                if (neg) {
                        slen = cbor_encode_key(&work_dbuff, -9);
                        if (slen <= 0) return_slen;
 
                        slen = cbor_encode_int64(&work_dbuff, neg);
                        if (slen <= 0) return_slen;
                }
                break;
 
                /*
                 *      RFC 9164, Section 3.3
                 *
                 *
                 *      tag=IPv4 + address + optional (prefix + scope)
                 */
        case FR_TYPE_IPV4_ADDR:
                slen = cbor_encode_tag(&work_dbuff, cbor_type_to_tag[vb->type]);
                if (slen <= 0) return_slen;
 
                if (vb->vb_ip.scope_id != 0) {
                        FR_DBUFF_IN_BYTES_RETURN(&work_dbuff, (uint8_t) ((CBOR_ARRAY << 5) | 3));
 
                }
 
                slen = cbor_encode_octets(&work_dbuff, (uint8_t const *) &vb->vb_ip.addr.v4.s_addr, 4);
                if (slen <= 0) return_slen;
 
                if (vb->vb_ip.scope_id == 0) break;
 
                slen = cbor_encode_integer(&work_dbuff, CBOR_INTEGER, (uint8_t) 32);
                if (slen <= 0) return_slen;
 
                slen = cbor_encode_integer(&work_dbuff, CBOR_INTEGER, vb->vb_ip.scope_id);
                if (slen <= 0) return_slen;
                break;
 
                /*
                 *      RFC 9164, Section 3.2
                 *
                 *      tag=IPv6 + address + optional (prefix + scope)
                 */
        case FR_TYPE_IPV6_ADDR:
                if (vb->vb_ip.scope_id != 0) {
                        FR_DBUFF_IN_BYTES_RETURN(&work_dbuff, (uint8_t) ((CBOR_ARRAY << 5) | 3));
 
                }
 
                slen = cbor_encode_tag(&work_dbuff, cbor_type_to_tag[vb->type]);
                if (slen <= 0) return_slen;
 
                slen = cbor_encode_octets(&work_dbuff, (uint8_t const *) &vb->vb_ip.addr.v6.s6_addr, 16);
                if (slen <= 0) return_slen;
 
                if (vb->vb_ip.scope_id == 0) break;
 
                slen = cbor_encode_integer(&work_dbuff, CBOR_INTEGER, (uint8_t) 32);
                if (slen <= 0) return_slen;
 
                slen = cbor_encode_integer(&work_dbuff, CBOR_INTEGER, vb->vb_ip.scope_id);
                if (slen <= 0) return_slen;
                break;
 
                /*
                 *      RFC 9164, Section 3.3
                 *
                 *      tag=IPv4 + array(prefix-length, address)
                 */
        case FR_TYPE_IPV4_PREFIX:
                slen = cbor_encode_tag(&work_dbuff, cbor_type_to_tag[vb->type]);
                if (slen <= 0) return_slen;
 
                slen = cbor_encode_array(&work_dbuff, 2);
                if (slen <= 0) return_slen;
 
                slen = cbor_encode_integer(&work_dbuff, CBOR_INTEGER, vb->vb_ip.prefix);
                if (slen <= 0) return_slen;
 
                p = (uint8_t const *) &vb->vb_ip.addr.v4.s_addr;
                end = p + 3;
 
                /*
                 *      RFC 9164 Section 4.2 - Drop lower octets which are all zero.
                 *
                 *      If this results in a zero-length string, so be it.
                 *
                 *      Note also that "There is no relationship between the number of bytes omitted and the
                 *      prefix length."
                 */
                do {
                        if (*end != 0) break;
 
                        end--;
                } while (end != p);
 
                slen = cbor_encode_octets(&work_dbuff, p, (end - p) + (*end != 0));
                if (slen <= 0) return_slen;
                break;
 
                /*
                 *      RFC 9164, Section 3.2
                 *
                 *      tag=IPv6 + array(prefix-length, address)
                 */
        case FR_TYPE_IPV6_PREFIX:
                slen = cbor_encode_tag(&work_dbuff, cbor_type_to_tag[vb->type]);
                if (slen <= 0) return_slen;
 
                slen = cbor_encode_array(&work_dbuff, 2);
                if (slen <= 0) return_slen;
 
                slen = cbor_encode_integer(&work_dbuff, CBOR_INTEGER, vb->vb_ip.prefix);
                if (slen <= 0) return_slen;
 
                p = (uint8_t const *) &vb->vb_ip.addr.v6.s6_addr;
                end = p + 15;
 
                /*
                 *      RFC 9164 Section 4.2 - Drop lower octets which are all zero.
                 *
                 *      If this results in a zero-length string, so be it.
                 *
                 *      Note also that "There is no relationship between the number of bytes omitted and the
                 *      prefix length."
                 */
                do {
                        if (*end != 0) break;
 
                        end--;
                } while (end != p);
 
                slen = cbor_encode_octets(&work_dbuff, p, (end - p) + (*end != 0));
                if (slen <= 0) return_slen;
 
                break;
 
        case FR_TYPE_FLOAT32:
                FR_DBUFF_IN_BYTES_RETURN(&work_dbuff, (uint8_t) ((CBOR_FLOAT << 5) | CBOR_4_BYTE));
 
                slen = cbor_encode_octets(&work_dbuff, (uint8_t const *) &vb->vb_float32, 4);
                if (slen <= 0) return_slen;
                break;
 
        case FR_TYPE_FLOAT64:
                FR_DBUFF_IN_BYTES_RETURN(&work_dbuff, (uint8_t) ((CBOR_FLOAT << 5) | CBOR_8_BYTE));
 
                slen = cbor_encode_octets(&work_dbuff, (uint8_t const *) &vb->vb_float64, 8);
                if (slen <= 0) return_slen;
                break;
 
        case FR_TYPE_GROUP:
                /*
                 *      Zero-length array.
                 */
                if (fr_value_box_list_num_elements(&vb->vb_group) == 0) {
                        FR_DBUFF_IN_BYTES_RETURN(&work_dbuff, (uint8_t) ((CBOR_ARRAY << 5) | 0));
                        break;
                }
 
                /*
                 *      The value is array(children)
                 */
                slen = cbor_encode_integer(&work_dbuff, CBOR_ARRAY,
                                           fr_value_box_list_num_elements(&vb->vb_group));
                if (slen <= 0) return_slen;
 
 
                fr_value_box_list_foreach(&vb->vb_group, child) {
                        slen = fr_cbor_encode_value_box(&work_dbuff, child);
                        if (slen <= 0) return_slen;
                }
                break;
 
 
        default:
                fr_strerror_printf("Invalid data type %s for cbor encoding", fr_type_to_str(vb->type));
                return -1;
        }
 
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
 
static ssize_t cbor_decode_integer(uint64_t *out, uint8_t info, fr_dbuff_t *dbuff)
{
        fr_dbuff_t work_dbuff = FR_DBUFF(dbuff);
 
        if (info < 24) {
                *out = info;
                return 0;
        }
 
        if (info == CBOR_1_BYTE) {
                uint8_t value;
 
                FR_DBUFF_OUT_RETURN(&value, &work_dbuff);
                *out = value;
                goto done;
        }
 
        if (info == CBOR_2_BYTE) {
                uint16_t value;
 
                FR_DBUFF_OUT_RETURN(&value, &work_dbuff);
                *out = value;
                goto done;
        }
 
        if (info == CBOR_4_BYTE) {
                uint32_t value;
 
                FR_DBUFF_OUT_RETURN(&value, &work_dbuff);
                *out = value;
                goto done;
        }
 
        if (info == CBOR_8_BYTE) {
                uint64_t value;
 
                FR_DBUFF_OUT_RETURN(&value, &work_dbuff);
                *out = value;
                goto done;
        }
 
        /*
         *      28 and greater are invalid according to the RFCs.
         */
 
done:
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
static ssize_t cbor_decode_count(uint64_t *out, int expected, fr_dbuff_t *dbuff)
{
        fr_dbuff_t work_dbuff = FR_DBUFF(dbuff);
        uint8_t major, info;
        ssize_t slen;
 
        FR_DBUFF_OUT_RETURN(&major, &work_dbuff);
 
        info = major & 0x1f;
        major >>= 5;
 
        if (major != expected) {
                fr_strerror_printf("Expected cbor type '%s', got unexpected type %d ",
                                   cbor_type_to_str[expected], major);
                return -1;
        }
 
        slen = cbor_decode_integer(out, info, &work_dbuff);
        if (slen < 0) return_slen;
 
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
typedef ssize_t (*cbor_decode_type_t)(TALLOC_CTX *ctx, fr_value_box_t *vb, fr_dbuff_t *dbuff);
 
static ssize_t cbor_decode_octets_memcpy(uint8_t *dst, size_t dst_min, size_t dst_max, fr_dbuff_t *dbuff)
{
        fr_dbuff_t work_dbuff = FR_DBUFF(dbuff);
        ssize_t slen;
        uint64_t value = 0;
 
        slen = cbor_decode_count(&value, CBOR_OCTETS, &work_dbuff);
        if (slen < 0) return_slen;
 
        if (value < dst_min) {
                fr_strerror_printf("Invalid length for data - expected at least %zu got %" PRIu64, dst_min, value);
                return -1;
        }
 
        if (value > dst_max) {
                fr_strerror_printf("Invalid length for data - expected no more than %zu got %" PRIu64, dst_max, value);
                return -1;
        }
 
        FR_DBUFF_OUT_MEMCPY_RETURN(dst, &work_dbuff, value);
 
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
#if 0
static ssize_t *cbor_decode_octets_memdup(TALLOC_CTX *ctx, uint8_t **out, fr_dbuff_t *dbuff)
{
        fr_dbuff_t work_dbuff = FR_DBUFF(dbuff);
        ssize_t slen;
        uint64_t value;
        uint8_t *ptr;
 
        slen = cbor_decode_count(&value, CBOR_OCTETS, &work_dbuff);
        if (slen < 0) return_slen;
 
        if (value > (1 << 20)) {
                fr_strerror_printf("cbor data string is too long (%" PRIu64 ")", value);
                return -1;
        }
 
        ptr = talloc_array(ctx, uint8_t, value);
        if (!ptr) {
                fr_strerror_const("Out of memory");
                return -1;
        }
 
        FR_DBUFF_OUT_MEMCPY_RETURN(ptr, &work_dbuff, value);
        *out = ptr;
 
        return fr_dbuff_set(dbuff, &work_dbuff);
}
#endif
 
static ssize_t cbor_decode_ethernet(UNUSED TALLOC_CTX *ctx, fr_value_box_t *vb, fr_dbuff_t *dbuff)
{
        return cbor_decode_octets_memcpy(vb->vb_ether, sizeof(vb->vb_ether), sizeof(vb->vb_ether), dbuff);
}
 
static ssize_t cbor_decode_ipv4_addr(UNUSED TALLOC_CTX *ctx, fr_value_box_t *vb, fr_dbuff_t *dbuff)
{
        fr_dbuff_t work_dbuff = FR_DBUFF(dbuff);
        ssize_t slen;
        uint8_t header;
        size_t count = 0;
        uint64_t value = 0;
 
        FR_DBUFF_EXTEND_LOWAT_OR_RETURN(&work_dbuff, 1);
 
        header = *fr_dbuff_current(&work_dbuff);
        if ((header >> 5) == CBOR_ARRAY) {
                count = header & 0x1f;
 
                if ((count != 2) && (count != 3)) {
                        fr_strerror_printf("Invalid IPv4 interface - expected array of 2-3 elements, got %02x",
                                           header);
                        return -1;
                }
 
                fr_dbuff_advance(&work_dbuff, 1);
        }
 
        vb->vb_ip.prefix = 32;
 
        /*
         *      Get the IP address.
         */
        slen = cbor_decode_octets_memcpy((uint8_t *) &vb->vb_ip.addr.v4.s_addr,
                                         sizeof(vb->vb_ip.addr.v4.s_addr),
                                         sizeof(vb->vb_ip.addr.v4.s_addr), &work_dbuff);
        if (slen <= 0) return_slen;
 
        if (!count) return fr_dbuff_set(dbuff, &work_dbuff);
 
        slen = cbor_decode_count(&value, CBOR_INTEGER, &work_dbuff);
        if (slen <= 0) return_slen;
 
        if (value != 32) {
                fr_strerror_printf("Invalid IPv4 address - expected prefix = 32 got %" PRIu64, value);
                return -fr_dbuff_used(&work_dbuff);
        }
 
        if (count == 2) return fr_dbuff_set(dbuff, &work_dbuff);
 
        /*
         *      Get the scope ID
         */
        slen = cbor_decode_count(&value, CBOR_INTEGER, &work_dbuff);
        if (slen <= 0) return_slen;
 
        vb->vb_ip.scope_id = value;
 
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
static ssize_t cbor_decode_ipv6_addr(UNUSED TALLOC_CTX *ctx, fr_value_box_t *vb, fr_dbuff_t *dbuff)
{
        fr_dbuff_t work_dbuff = FR_DBUFF(dbuff);
        ssize_t slen;
        uint8_t header;
        size_t count = 0;
        uint64_t value = 0;
 
        FR_DBUFF_EXTEND_LOWAT_OR_RETURN(&work_dbuff, 1);
 
        header = *fr_dbuff_current(&work_dbuff);
        if ((header >> 5) == CBOR_ARRAY) {
                count = header & 0x1f;
 
                if ((count != 2) && (count != 3)) {
                        fr_strerror_printf("Invalid IPv4 interface - expected array of 2-3 elements, got %02x",
                                           header);
                        return -1;
                }
 
                fr_dbuff_advance(&work_dbuff, 1);
        }
 
        vb->vb_ip.prefix = 128;
 
        /*
         *      Get the IP address.
         */
        slen = cbor_decode_octets_memcpy((uint8_t *) &vb->vb_ip.addr.v6.s6_addr,
                                         sizeof(vb->vb_ip.addr.v6.s6_addr),
                                         sizeof(vb->vb_ip.addr.v6.s6_addr), dbuff);
 
        if (slen <= 0) return_slen;
 
        if (!count) return fr_dbuff_set(dbuff, &work_dbuff);
 
        slen = cbor_decode_count(&value, CBOR_INTEGER, &work_dbuff);
        if (slen <= 0) return_slen;
 
        if (value != 128) {
                fr_strerror_printf("Invalid IPv6 address - expected prefix = 128 got %" PRIu64, value);
                return -fr_dbuff_used(&work_dbuff);
        }
 
        vb->vb_ip.prefix = value;
 
        if (count == 2) return fr_dbuff_set(dbuff, &work_dbuff);
 
        /*
         *      Get the scope ID
         */
        slen = cbor_decode_count(&value, CBOR_INTEGER, &work_dbuff);
        if (slen <= 0) return_slen;
 
        vb->vb_ip.scope_id = value;
 
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
static ssize_t cbor_decode_ipv4_prefix(UNUSED TALLOC_CTX *ctx, fr_value_box_t *vb, fr_dbuff_t *dbuff)
{
        fr_dbuff_t work_dbuff = FR_DBUFF(dbuff);
        ssize_t slen;
        uint8_t header;
        uint64_t value = 0;
        uint8_t buffer[sizeof(vb->vb_ip.addr.v4.s_addr)];
 
        FR_DBUFF_OUT_RETURN(&header, &work_dbuff);
 
        if (header != ((CBOR_ARRAY << 5) | 2)) {
                fr_strerror_printf("Invalid IPv4 prefix - expected array of 2 elements, got %02x",
                                   header);
                return -1;
        }
 
        slen = cbor_decode_count(&value, CBOR_INTEGER, &work_dbuff);
        if (slen <= 0) return_slen;
 
        if (value > 32) {
                fr_strerror_printf("Invalid IPv4 prefix - expected prefix < 32, got %" PRIu64, value);
                return -1;
        }
 
        /*
         *      RFC 9164 Section 4.3 - Trailing bytes of zero are omitted, so we
         *      first copy the data to a fixed-sized buffer which was
         *      zeroed out, and then (@todo) also check that unused bits in
         *      the last byte are all zero.
         */
        memset(buffer, 0, sizeof(buffer));
 
        slen = cbor_decode_octets_memcpy(buffer, 0, sizeof(buffer), &work_dbuff);
        if (slen <= 0) return_slen;
 
        memcpy((uint8_t *) &vb->vb_ip.addr.v4.s_addr, buffer, sizeof(vb->vb_ip.addr.v4.s_addr));
        vb->vb_ip.prefix = value;
 
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
static ssize_t cbor_decode_ipv6_prefix(UNUSED TALLOC_CTX *ctx, fr_value_box_t *vb, fr_dbuff_t *dbuff)
{
        fr_dbuff_t work_dbuff = FR_DBUFF(dbuff);
        ssize_t slen;
        uint8_t header;
        uint64_t value = 0;
        uint8_t buffer[sizeof(vb->vb_ip.addr.v6.s6_addr)];
 
        FR_DBUFF_OUT_RETURN(&header, &work_dbuff);
 
        if (header != ((CBOR_ARRAY << 5) | 2)) {
                fr_strerror_printf("Invalid IPv6 prefix - expected array of 2 elements, got %02x",
                                   header);
                return -1;
        }
 
        slen = cbor_decode_count(&value, CBOR_INTEGER, &work_dbuff);
        if (slen <= 0) return_slen;
 
        if (value > 128) {
                fr_strerror_printf("Invalid IPv6 prefix - expected prefix < 128, got %" PRIu64, value);
                return -1;
        }
 
        /*
         *      RFC 9164 Section 4.3 - Trailing bytes of zero are omitted, so we
         *      first copy the data to a fixed-sized buffer which was
         *      zeroed out, and then (@todo) also check that unused bits in
         *      the last byte are all zero.
         */
        memset(buffer, 0, sizeof(buffer));
 
        slen = cbor_decode_octets_memcpy(buffer, 0, sizeof(buffer), &work_dbuff);
        if (slen <= 0) return_slen;
 
        memcpy((uint8_t *) &vb->vb_ip.addr.v6.s6_addr, buffer, sizeof(vb->vb_ip.addr.v6.s6_addr));
        vb->vb_ip.prefix = value;
 
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
static ssize_t cbor_decode_int64(int64_t *out, fr_dbuff_t *dbuff, fr_type_t type)
{
        fr_dbuff_t work_dbuff = FR_DBUFF(dbuff);
        ssize_t slen;
        uint8_t major, info;
        uint64_t value = 0;
        int64_t neg;
 
        FR_DBUFF_OUT_RETURN(&major, &work_dbuff);
 
        info = major & 0x1f;
        major >>= 5;
 
        switch (major) {
        case CBOR_INTEGER:
                slen = cbor_decode_integer(&value, info, &work_dbuff);
                if (slen < 0) return_slen;
 
                if (value >= ((uint64_t) 1) << 63) { /* equal! */
                invalid:
                        fr_strerror_printf("cbor value is too large for output data type %s",
                                           fr_type_to_str(type));
                        return -1;
                }
 
                *out = value;
                break;
 
        case CBOR_NEGATIVE:
                slen = cbor_decode_integer(&value, info, &work_dbuff);
                if (slen < 0) return_slen;
 
                if (value >= ((uint64_t) 1) << 63) goto invalid; /* greater than! */
 
                /*
                 *      Convert 0..(2^63-1) into -0..-(2^63-1)
                 *      then conver to -1..-(2^63)
                 */
                neg = -value;
                neg--;
 
                *out = neg;
                break;
 
        default:
                fr_strerror_printf("cbor data contains invalid content %d for expected data type %s",
                                   major, fr_type_to_str(type));
                return -1;
        }
 
        return fr_dbuff_set(dbuff, &work_dbuff);
 
}
 
static ssize_t cbor_decode_date(UNUSED TALLOC_CTX *ctx, fr_value_box_t *vb, fr_dbuff_t *dbuff)
{
        fr_dbuff_t work_dbuff = FR_DBUFF(dbuff);
        ssize_t slen;
        int64_t neg;
 
        slen = cbor_decode_int64(&neg, dbuff, FR_TYPE_DATE);
        if (slen <= 0) return_slen;
 
        vb->vb_date = fr_unix_time_from_sec(neg);
 
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
/*
 *      Tag 1002, followed by map of at least 2 elements
 *      key 1: seconds
 *      key -9: nanoseconds
 */
static ssize_t cbor_decode_time_delta(UNUSED TALLOC_CTX *ctx, fr_value_box_t *vb, fr_dbuff_t *dbuff)
{
        fr_dbuff_t work_dbuff = FR_DBUFF(dbuff);
        uint64_t count;
        ssize_t slen;
        int64_t key, seconds, fraction, scale;
 
        slen = cbor_decode_count(&count, CBOR_MAP, &work_dbuff);
        if (slen < 0) return_slen;
 
        if (!count || (count > 2)) {
                fr_strerror_printf("Unexpected count %" PRIu64"  for time_delta, expected map of 1-2 elements", count);
                return -1;
        }
 
        key = seconds = fraction = 0;
 
        /*
         *      Expect key 1:seconds
         */
        slen = cbor_decode_int64(&key, &work_dbuff, FR_TYPE_TIME_DELTA);
        if (slen < 0) return_slen;
 
        if (key != 1) {
                fr_strerror_printf("Unexpected key %" PRIi64 " for time_delta, expected key 1", key);
                return -1;
        }
 
        slen = cbor_decode_int64(&seconds, &work_dbuff, FR_TYPE_TIME_DELTA);
        if (slen < 0) return_slen;
 
        if (count > 1) {
                slen = cbor_decode_int64(&key, &work_dbuff, FR_TYPE_TIME_DELTA);
                if (slen < 0) return_slen;
 
                switch (key) {
                case -3:
                        scale = MSEC;
                        break;
 
                case -6:
                        scale = USEC;
                        break;
 
                case -9:
                        scale = NSEC;
                        break;
 
                default:
                        fr_strerror_printf("Unsupported time_delta key %" PRIi64, key);
                        return -fr_dbuff_used(&work_dbuff); /* point to actual key? */
 
                }
 
                slen = cbor_decode_int64(&fraction, &work_dbuff, FR_TYPE_TIME_DELTA);
                if (slen < 0) return_slen;
 
                if ((fraction < 0) || (fraction > scale)) fraction = 0;
        } else {
                scale = NSEC;
                fraction = 0;
        }
 
        if (seconds > (INT64_MAX / scale)) {
                vb->vb_time_delta = fr_time_delta_max();
 
        } else if (seconds < (INT64_MIN / scale)) {
                vb->vb_time_delta = fr_time_delta_min();
 
        } else {
                seconds *= scale;
 
                if (seconds < 0) {
                        seconds -= fraction;
                } else {
                        seconds += fraction;
                }
 
                vb->vb_time_delta = fr_time_delta_wrap(seconds);
        }
 
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
 
static cbor_decode_type_t cbor_decode_type[FR_TYPE_MAX] = {
        [FR_TYPE_ETHERNET] = cbor_decode_ethernet,
 
        [FR_TYPE_DATE] = cbor_decode_date,
        [FR_TYPE_TIME_DELTA] = cbor_decode_time_delta,
 
        [FR_TYPE_IPV4_ADDR] = cbor_decode_ipv4_addr,
        [FR_TYPE_IPV6_ADDR] = cbor_decode_ipv6_addr,
 
        [FR_TYPE_IPV4_PREFIX] = cbor_decode_ipv4_prefix,
        [FR_TYPE_IPV6_PREFIX] = cbor_decode_ipv6_prefix,
};
 
/*
 *      @todo - fr_cbor_encode_pair_list().  And then if we have da->flags.array, we encode the _value_ as an
 *      array of indeterminate length.  This is a little bit of a special case, but not terrible.
 */
ssize_t fr_cbor_decode_value_box(TALLOC_CTX *ctx, fr_value_box_t *vb, fr_dbuff_t *dbuff,
                                 fr_type_t type, fr_dict_attr_t const *enumv, bool tainted)
{
        fr_dbuff_t work_dbuff = FR_DBUFF(dbuff);
        bool indefinite;
        uint8_t major, info;
        ssize_t slen;
        int64_t neg;
        uint64_t value;
        uint8_t *ptr;
 
        FR_DBUFF_OUT_RETURN(&major, &work_dbuff);
 
        if (type == FR_TYPE_NULL) {
                type = cbor_guess_type(&work_dbuff, false);
                if (type == FR_TYPE_NULL) return 0;
        }
 
        fr_value_box_init(vb, type, enumv, tainted);
 
        info = major & 0x1f;
        major >>= 5;
 
        /*
         *      Invalid combinations.
         */
        if (((info >= 28) && (info <= 30)) ||
            ((info == 31) && ((major == 0) || (major == 1) || (major == 6)))) {
                fr_strerror_const("Invalid cbor data - input is not 'well formed'");
                return 0;
        }
 
        switch (major) {
        case CBOR_STRING:
                if (type != FR_TYPE_STRING) {
                mismatch:
                        fr_strerror_printf("cbor data contains invalid content %d for expected data type %s",
                                           major, fr_type_to_str(type));
                        return -1;
                }
 
                if (info == 31) {
                no_chunks:
                        fr_strerror_const("Chunked strings are not supported");
                        return 0;
                }
 
 
                /*
                 *      @todo - undefinite length strings.  Which are really "chunked" strings.
                 */
                slen = cbor_decode_integer(&value, info, &work_dbuff);
                if (slen < 0) return_slen;
 
                /*
                 *      A little bit of sanity check.
                 */
                if (value > (1 << 20)) {
                        fr_strerror_printf("cbor data string is too long (%" PRIu64 ")", value);
                        return -1;
                }
 
                ptr = talloc_array(ctx, uint8_t, value + 1);
                if (!ptr) {
                        fr_strerror_const("Out of memory");
                        return -1;
                }
                talloc_set_type(ptr, char);
                if (value) FR_DBUFF_OUT_MEMCPY_RETURN(ptr, &work_dbuff, value);
                ptr[value] = '\0';
 
                fr_value_box_strdup_shallow(vb, NULL, (char const *) ptr, tainted);
 
                break;
 
        case CBOR_OCTETS:
                if (type != FR_TYPE_OCTETS) goto mismatch;
 
                if (info == 31) goto no_chunks;
 
                /*
                 *      @todo - indefinite length octet strings.  Which are really "chunked" octet strings.
                 */
                slen = cbor_decode_integer(&value, info, &work_dbuff);
                if (slen < 0) return_slen;
 
                /*
                 *      A little bit of sanity check.
                 */
                if (value > (1 << 20)) {
                        fr_strerror_printf("cbor data string is too long (%" PRIu64 ")", value);
                        return -1;
                }
 
                ptr = talloc_array(ctx, uint8_t, value);
                if (!ptr) {
                        fr_strerror_const("Out of memory");
                        return -1;
                }
 
                fr_value_box_memdup_shallow(vb, NULL, (uint8_t const *) ptr, value, false); /* tainted? */
 
                if (value) FR_DBUFF_OUT_MEMCPY_RETURN(ptr, &work_dbuff, value);
                break;
 
        case CBOR_INTEGER:
                slen = cbor_decode_integer(&value, info, &work_dbuff);
                if (slen < 0) return_slen;
 
                switch (type) {
                case FR_TYPE_BOOL:
                        if (value > 1) goto invalid_bool;
                        vb->vb_bool = value;
                        break;
 
                case FR_TYPE_UINT8:
                        if (value > UINT8_MAX) {
                        invalid:
                                fr_strerror_printf("cbor value is too large for output data type %s",
                                                   fr_type_to_str(type));
                                return -1;
                        }
                        vb->vb_uint8 = value;
                        break;
 
                case FR_TYPE_UINT16:
                        if (value > UINT16_MAX) goto invalid;
                        vb->vb_uint16 = value;
                        break;
 
                case FR_TYPE_UINT32:
                        if (value > UINT32_MAX) goto invalid;
                        vb->vb_uint32 = value;
                        break;
 
                case FR_TYPE_UINT64:
                        vb->vb_uint64 = value;
                        break;
 
                case FR_TYPE_INT8:
                        if (value > INT8_MAX) goto invalid;
                        vb->vb_int8 = value;
                        break;
 
                case FR_TYPE_INT16:
                        if (value > INT16_MAX) goto invalid;
                        vb->vb_int16 = value;
                        break;
 
                case FR_TYPE_INT32:
                        if (value > INT32_MAX) goto invalid;
                        vb->vb_int32 = value;
                        break;
 
                case FR_TYPE_INT64:
                        if (value > INT64_MAX) goto invalid;
                        vb->vb_int64 = value;
                        break;
 
                default:
                integer_type_mismatch:
                        fr_strerror_printf("Unexpected cbor type 'integer' when decoding data type %s",
                                           fr_type_to_str(type));
                        return -1;
                }
                break;
 
        case CBOR_NEGATIVE:
                slen = cbor_decode_integer(&value, info, &work_dbuff);
                if (slen < 0) return_slen;
 
                /*
                 *      Signed numbers only go down to -2^63
                 *      so value must be less than 2^63
                 */
                if (value >= ((uint64_t) 1) << 63) goto invalid;
 
                /*
                 *      Convert 0..(2^63-1) into -0..-(2^63-1)
                 *      then conver to -1..-(2^63)
                 */
                neg = -value;
                neg--;
 
                switch (type) {
                case FR_TYPE_INT8:
                        if (neg < INT8_MIN) goto invalid;
                        vb->vb_int8 = neg;
                        break;
 
                case FR_TYPE_INT16:
                        if (neg < INT16_MIN) goto invalid;
                        vb->vb_int16 = neg;
                        break;
 
                case FR_TYPE_INT32:
                        if (neg < INT32_MIN) goto invalid;
                        vb->vb_int32 = neg;
                        break;
 
                case FR_TYPE_INT64:
                        vb->vb_int64 = neg;
                        break;
 
                default:
                        goto integer_type_mismatch;
                }
                break;
 
        case CBOR_FLOAT:
                /*
                 *      Simple values.  See RFC 8489 Section 3.3.
                 *
                 *      20 - false
                 *      21 - true
                 *      22 - NULL
                 */
                if (info < 24) {
                        switch (type) {
                        case FR_TYPE_BOOL:
                                if (info == 20) {
                                        vb->vb_bool = false;
                                        break;
                                }
 
                                if (info == 21) {
                                        vb->vb_bool = true;
                                        break;
                                }
 
                        invalid_bool:
                                fr_strerror_printf("Invalid cbor - boolean is not encoded as 'true' or 'false'");
                                return -fr_dbuff_used(&work_dbuff);
 
                        case FR_TYPE_OCTETS:
                        case FR_TYPE_STRING:
                        case FR_TYPE_TLV:
                        case FR_TYPE_VENDOR:
                        case FR_TYPE_GROUP:
                        case FR_TYPE_STRUCT:
                                /*
                                 *      Be a little forgiving.  22 is NULL, so we treat that as "nothing".
                                 *
                                 *      i.e. empty string, empty set, etc.
                                 */
                                if (info == 22) break;
 
                                FALL_THROUGH;
 
                        default:
                                fr_strerror_printf("Invalid cbor - unexpected 'simple value' %u", info);
                                return -fr_dbuff_used(&work_dbuff);
                        }
                        break;
                }
 
                /*
                 *      Or as one-byte integers.
                 */
                if (info == CBOR_1_BYTE) {
                        uint8_t data;
 
                        FR_DBUFF_OUT_RETURN(&data, &work_dbuff);
 
                        switch (type) {
                        case FR_TYPE_FLOAT32:
                                vb->vb_float32 = data;
                                break;
 
                        case FR_TYPE_FLOAT64:
                                vb->vb_float64 = data;
                                break;
 
                        default:
                        float_type_mismatch:
                                fr_strerror_printf("Unexpected cbor type 'float' when decoding data type %s",
                                                   fr_type_to_str(type));
                                return -1;
                        }
 
                        break;
                }
 
                /*
                 *      We don't support float16
                 */
 
                if (info == CBOR_4_BYTE) {
                        float data;
 
                        FR_DBUFF_OUT_RETURN(&data, &work_dbuff);
 
                        switch (type) {
                        case FR_TYPE_FLOAT32:
                                vb->vb_float32 = data;
                                break;
 
                        case FR_TYPE_FLOAT64:
                                vb->vb_float64 = (double) data;
                                break;
 
                        default:
                                goto float_type_mismatch;
                        }
 
                        break;
                }
 
                if (info == CBOR_8_BYTE) {
                        double data;
 
                        FR_DBUFF_OUT_RETURN(&data, &work_dbuff);
 
                        switch (type) {
                        case FR_TYPE_FLOAT32:
                                vb->vb_float32 = data; /* maybe loses precision? */
                                break;
 
                        case FR_TYPE_FLOAT64:
                                vb->vb_float64 = data;
                                break;
 
                        default:
                                goto float_type_mismatch;
                        }
 
                        break;
                }
 
                /*
                 *      24 is FLOAT16, which we don't support.
                 *      31 is BREAK, which the caller should have checked for.
                 */
                goto float_type_mismatch;
 
        case CBOR_TAG:
                /*
                 *      We only support a limited number of tags.
                 */
                slen = cbor_decode_integer(&value, info, &work_dbuff);
                if (slen < 0) return_slen;
 
                fr_assert(type != FR_TYPE_NULL);
 
                /*
                 *      No tag defined for this data type, that's on us.
                 */
                if (!cbor_type_to_tag[type]) {
                        fr_strerror_printf("Unknown cbor tag %" PRIu64 " for expected data type %s",
                                           value, fr_type_to_str(type));
                        return -fr_dbuff_used(&work_dbuff);
                }
 
                /*
                 *      Wrong tag for this data type, that's on them.
                 */
                if (cbor_type_to_tag[type] != value) {
                        fr_strerror_printf("Invalid cbor tag %" PRIu64 " for expected data type %s",
                                           value, fr_type_to_str(type));
                        return -fr_dbuff_used(&work_dbuff);
                }
 
                fr_value_box_init(vb, type, enumv, tainted);
 
                slen = cbor_decode_type[type](ctx, vb, &work_dbuff);
                if (slen < 0) return_slen;
                break;
 
        case CBOR_ARRAY:
                if (type != FR_TYPE_GROUP) goto invalid_type;
 
                /*
                 *      Loop until done.
                 */
                if (info == 31) {
                        value = ~0;
                        indefinite = true;
 
                } else {
                        slen = cbor_decode_integer(&value, info, &work_dbuff);
                        if (slen < 0) return_slen;
 
                        indefinite = false;
                }
 
#ifdef STATIC_ANALYZER
                if (value > fr_dbuff_remaining(&work_dbuff)) return -1;
#endif
 
                /*
                 *      Loop until we decode everything.  For simplicity, we handle indefinite and definite
                 *      length arrays in the same loop.
                 */
                for (/* nothing */; value > 0; value--) {
                        uint8_t header;
                        fr_value_box_t *child;
 
                        /*
                         *      Require at least one byte in the buffer.
                         */
                        FR_DBUFF_EXTEND_LOWAT_OR_RETURN(&work_dbuff, 1);
 
                        /*
                         *      Peek ahead for a break.
                         */
                        header = *fr_dbuff_current(&work_dbuff);
                        if (header == 0xff) {
                                if (!indefinite) {
                                        fr_strerror_const("Unexpected 'break' found in cbor data");
                                        return -fr_dbuff_used(&work_dbuff);
                                }
 
                                /*
                                 *      Done!
                                 */
                                fr_dbuff_advance(&work_dbuff, 1);
                                break;
                        }
 
                        child = fr_value_box_alloc(ctx, FR_TYPE_NULL, NULL);
                        if (!child) {
                                fr_strerror_const("Out of memory");
                                return -fr_dbuff_used(&work_dbuff);
                        }
 
                        /*
                         *      We have to decode at least one value.
                         */
                        slen = fr_cbor_decode_value_box(child, child, &work_dbuff, FR_TYPE_NULL, NULL, tainted);
                        if (slen <= 0) return_slen;
 
                        fr_value_box_list_insert_tail(&vb->vb_group, child);
                }
                break;
 
                /*
                 *      These are not value-box types.
                 */
        case CBOR_MAP:
        invalid_type:
                fr_strerror_printf("Invalid data type %s for cbor to value-box", fr_type_to_str(type));
                return -1;
        }
 
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
/** Encode a pair
 *
 */
ssize_t fr_cbor_encode_pair(fr_dbuff_t *dbuff, fr_pair_t *vp)
{
        fr_dbuff_t      work_dbuff = FR_DBUFF(dbuff);
        ssize_t         slen;
        fr_dict_attr_t const *parent;
        size_t          count;
 
        FR_DBUFF_IN_BYTES_RETURN(&work_dbuff, (uint8_t) ((CBOR_MAP << 5) | 1)); /* map of 1 item */
 
        /*
         *      Key is the attribute number.
         */
        slen = cbor_encode_integer(&work_dbuff, CBOR_INTEGER, vp->da->attr);
        if (slen <= 0) return_slen;
 
        /*
         *      Value is the actual value of the leaf, or the array of children.
         */
        switch (vp->vp_type) {
        case FR_TYPE_LEAF:
                slen = fr_cbor_encode_value_box(&work_dbuff, &vp->data);
                if (slen <= 0) return_slen;
                break;
 
                /*
                 *      Groups reparent to the ref.
                 */
        case FR_TYPE_GROUP:
                parent = fr_dict_attr_ref(vp->da);
                fr_assert(parent != NULL);
                goto encode_children;
 
                /*
                 *      The only difference between TLV and VSA is that the children of VSA are all VENDORs.
                 */
        case FR_TYPE_VENDOR:
        case FR_TYPE_VSA:
        case FR_TYPE_TLV:
                parent = vp->da;
 
                /*
                 *      The value is array(children)
                 */
encode_children:
                if (fr_pair_list_num_elements(&vp->vp_group) == 0) {
                        FR_DBUFF_IN_BYTES_RETURN(&work_dbuff, (uint8_t) ((CBOR_FLOAT << 5) | 22)); /* NULL */
                        break;
                }
 
                /*
                 *      The groups, etc. may contain internal attributes.  We don't yet deal with those.
                 */
                count = 0;
                fr_pair_list_foreach(&vp->vp_group, child) {
                        if (child->da->parent != parent) continue;
                        count++;
                }
 
                slen = cbor_encode_integer(&work_dbuff, CBOR_ARRAY, count);
                if (slen <= 0) return_slen;
 
                fr_pair_list_foreach(&vp->vp_group, child) {
                        /*
                         *      We don't allow changing dictionaries here.
                         */
                        if (child->da->parent != parent) continue;
 
                        slen = fr_cbor_encode_pair(&work_dbuff, child);
                        if (slen <= 0) return_slen;
                }
                break;
 
        /*
         *      @todo - struct, except if we hit the end of the struct, check if the next child is the child
         *      of the key?  That makes it all more annoying :(
         */
 
        default:
                fr_strerror_printf("Invalid data type %s for cbor encoding", fr_type_to_str(vp->vp_type));
                return -1;
        }
 
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
/** Guess the data type of the CBOR data.
 *
 *  We've parsed the attribute number, and found that we don't have a dictionary entry for it.  But rather
 *  than create an attribute of type octets, we try to guess the data type.
 */
static fr_type_t cbor_guess_type(fr_dbuff_t *dbuff, bool pair)
{
        fr_dbuff_t work_dbuff = FR_DBUFF(dbuff);
        ssize_t slen;
        uint8_t major, info;
        uint64_t value;
 
        /*
         *      get the next byte, which is a CBOR header.
         */
        slen = fr_dbuff_out(&major, &work_dbuff);
        if (slen <= 0) {
        no_data:
                fr_strerror_const("Invalid cbor - insufficient data");
                return FR_TYPE_NULL;
        }
 
        info = major & 0x1f;
        major >>= 5;
 
        switch (major) {
        case CBOR_INTEGER:
                return FR_TYPE_UINT64;
 
        case CBOR_NEGATIVE:
                return FR_TYPE_UINT64;
 
        case CBOR_STRING:
                return FR_TYPE_STRING;
 
        case CBOR_OCTETS:
                return FR_TYPE_OCTETS;
 
        case CBOR_ARRAY:
                if (!pair) return FR_TYPE_GROUP;
                break;
 
        case CBOR_MAP:
                return FR_TYPE_TLV;
 
                /*
                 *      Look at the tag to determine what it is
                 */
        case CBOR_TAG:
                slen = cbor_decode_integer(&value, info, &work_dbuff);
                if (slen < 0) break;
 
                switch (value) {
                case 1:
                case 1001:
                        return FR_TYPE_DATE;
 
                case 1002:
                        return FR_TYPE_TIME_DELTA;
 
                case 48:
                        return FR_TYPE_ETHERNET;
 
                case 52:
                        slen = fr_dbuff_out(&major, &work_dbuff);
                        if (slen <= 0) goto no_data;
 
                        major >>= 5;
 
                        if (major == CBOR_ARRAY) {
                                return FR_TYPE_IPV4_PREFIX;
                        }
                        return FR_TYPE_IPV4_ADDR;
 
                case 54:
                        slen = fr_dbuff_out(&major, &work_dbuff);
                        if (slen <= 0) goto no_data;
 
                        major >>= 5;
 
                        if (major == CBOR_ARRAY) {
                                return FR_TYPE_IPV6_PREFIX;
                        }
                        return FR_TYPE_IPV6_ADDR;
 
                default:
                        break;
                }
 
                break;
 
        case CBOR_FLOAT:
                /*
                 *      In-place values are special. false / true / NULL
                 */
                if (info < 24) {
                        if ((info == 20) || (info == 21)) return FR_TYPE_BOOL;
 
                        return FR_TYPE_NULL;
                }
 
                return FR_TYPE_FLOAT64;
        }
 
 
        /*
         *      No idea.  :(
         *
         *      @todo - also check the cbor data, and return the length of cbor data which needs to be
         *      converted to data type 'octets'.  This work involves mostly parsing the cbor data, which isn't
         *      trivial.
         */
        fr_strerror_const("Invalid cbor - unable to determine data type");
        return FR_TYPE_NULL;
}
 
ssize_t fr_cbor_decode_pair(TALLOC_CTX *ctx, fr_pair_list_t *out, fr_dbuff_t *dbuff,
                            fr_dict_attr_t const *parent, bool tainted)
{
        fr_dbuff_t work_dbuff = FR_DBUFF(dbuff);
        uint8_t header, major, info;
        bool indefinite;
        ssize_t slen;
        fr_pair_t *vp;
        uint64_t value = 0;
        fr_dict_attr_t const *da;
 
        FR_DBUFF_OUT_RETURN(&header, &work_dbuff);
 
        /*
         *      We require a 2-element array(attribute number, value)
         */
        if (header != (((CBOR_MAP) << 5) | 1)) {
                fr_strerror_printf("Invalid cbor header - expected map of 1 elements, got %02x", header);
                return -1;
        }
 
        /*
         *      This should be a CBOR_INTEGER.
         */
        FR_DBUFF_OUT_RETURN(&major, &work_dbuff);
 
        info = major & 0x1f;
        major >>= 5;
 
        if (major != CBOR_INTEGER) {
                fr_strerror_printf("Invalid cbor - expected 'integer', got major type %d",
                                   major);
                return -1;
        }
 
        slen = cbor_decode_integer(&value, info, &work_dbuff);
        if (slen < 0) {
                return_slen;
        }
 
        da = fr_dict_attr_child_by_num(parent, value);
        if (!da) {
                fr_type_t type;
 
                type = cbor_guess_type(&work_dbuff, true);
                if (type == FR_TYPE_NULL) return -fr_dbuff_used(&work_dbuff);
 
                /*
                 *      @todo - the value here isn't a cbor octets type, but is instead cbor data.  Since cbor
                 *      is typed, we _could_ perhaps instead discover the type from the cbor data, and then
                 *      use that instead.  This would involve creating a function which maps cbor types to our
                 *      data types.
                 */
                da = fr_dict_attr_unknown_typed_afrom_num(ctx, parent, value, type);
                if (!da) goto oom;
        }
 
        vp = fr_pair_afrom_da(ctx, da);
        if (!vp) {
        oom:
                fr_strerror_const("Out of memory");
                return -fr_dbuff_used(&work_dbuff);
        }
 
        /*
         *      Leaf values are easy.
         */
        if (fr_type_is_leaf(da->type)) {
                slen = fr_cbor_decode_value_box(vp, &vp->data, &work_dbuff, da->type, da, tainted);
                if (slen <= 0) {
                        talloc_free(vp);
                        return_slen;
                }
 
                goto done;
        }
 
        fr_assert(fr_type_is_structural(da->type));
 
        switch (da->type) {
                /*
                 *      All of these are essentially the same.
                 */
        case FR_TYPE_VENDOR:
        case FR_TYPE_VSA:
        case FR_TYPE_TLV:
                parent = vp->da;
                break;
 
                /*
                 *      Groups reparent to the ref.
                 */
        case FR_TYPE_GROUP:
                parent = fr_dict_attr_ref(vp->da);
                fr_assert(parent != NULL);
                break;
 
        default:
                fr_strerror_printf("Invalid data type %s for child %s of %s",
                                   fr_type_to_str(da->type), vp->da->name, parent->name);
                talloc_free(vp);
                return -1;
        }
 
        /*
         *      This should be a CBOR_ARRAY.
         */
        FR_DBUFF_OUT_RETURN(&major, &work_dbuff);
 
        info = major & 0x1f;
        major >>= 5;
 
        if (major != CBOR_ARRAY) {
                /*
                 *      Allow NULL as a synonym for "no children".
                 */
                if ((major == CBOR_FLOAT) && (info == 22)) goto done;
 
                talloc_free(vp);
                fr_strerror_printf("Invalid cbor - expected 'array', got major type %d",
                                   major);
                return -1;
        }
 
        if (info == 31) {
                value = ~0;
                indefinite = true;
 
        } else {
                slen = cbor_decode_integer(&value, info, &work_dbuff);
                if (slen < 0) {
                        talloc_free(vp);
                        return_slen;
                }
 
                indefinite = false;
        }
 
#ifdef STATIC_ANALYZER
        if (value > fr_dbuff_remaining(&work_dbuff)) return -1;
#endif
 
        /*
         *      Loop until we decode everything.  For simplicity, we handle indefinite and definite
         *      length arrays in the same loop.
         */
        for (/* nothing */; value > 0; value--) {
                /*
                 *      Require at least one byte in the buffer.
                 */
                if (fr_dbuff_extend_lowat(NULL, &work_dbuff, 1) == 0) {
                        talloc_free(vp);
                        return -fr_dbuff_used(&work_dbuff);
                }
 
                /*
                 *      Peek ahead for a break.
                 */
                header = *fr_dbuff_current(&work_dbuff);
                if (header == 0xff) {
                        if (!indefinite) {
                                talloc_free(vp);
                                fr_strerror_const("Unexpected 'break' found in cbor data");
                                return -fr_dbuff_used(&work_dbuff);
                        }
 
                        /*
                         *      Done!
                         */
                        fr_dbuff_advance(&work_dbuff, 1);
                        break;
                }
 
                slen = fr_cbor_decode_pair(vp, &vp->vp_group, &work_dbuff, parent, tainted);
                if (slen <= 0) {
                        talloc_free(vp);
                        return_slen;
                }
        }
 
done:
        PAIR_VERIFY(vp);
 
        fr_pair_append(out, vp);
        return fr_dbuff_set(dbuff, &work_dbuff);
}
 
/*
 *      @todo - cbor_print
 *      [] for array
 *      [_...] for indefinite array
 *      {a:b} for map
 *      digits for integer
 *      'string' for string
 *      h'HHHH' for octets
 *
 *      https://datatracker.ietf.org/doc/html/draft-ietf-cbor-edn-literals
 */