/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id: a6_38.c,v 1.14 2020/09/14 08:40:44 florian Exp $ */

/* RFC2874 */

#ifndef RDATA_IN_1_A6_28_C
#define RDATA_IN_1_A6_28_C

static inline isc_result_t
totext_in_a6(ARGS_TOTEXT) {
        isc_region_t sr, ar;
        unsigned char addr[16];
        unsigned char prefixlen;
        unsigned char octets;
        unsigned char mask;
        char buf[sizeof("128")];
        dns_name_t name;
        dns_name_t prefix;
        int sub;

        REQUIRE(rdata->type == dns_rdatatype_a6);
        REQUIRE(rdata->rdclass == dns_rdataclass_in);
        REQUIRE(rdata->length != 0);

        dns_rdata_toregion(rdata, &sr);
        prefixlen = sr.base[0];
        INSIST(prefixlen <= 128);
        isc_region_consume(&sr, 1);
        snprintf(buf, sizeof(buf), "%u", prefixlen);
        RETERR(isc_str_tobuffer(buf, target));
        RETERR(isc_str_tobuffer(" ", target));

        if (prefixlen != 128) {
                octets = prefixlen/8;
                memset(addr, 0, sizeof(addr));
                memmove(&addr[octets], sr.base, 16 - octets);
                mask = 0xff >> (prefixlen % 8);
                addr[octets] &= mask;
                ar.base = addr;
                ar.length = sizeof(addr);
                RETERR(inet_totext(AF_INET6, &ar, target));
                isc_region_consume(&sr, 16 - octets);
        }

        if (prefixlen == 0)
                return (ISC_R_SUCCESS);

        RETERR(isc_str_tobuffer(" ", target));
        dns_name_init(&name, NULL);
        dns_name_init(&prefix, NULL);
        dns_name_fromregion(&name, &sr);
        sub = name_prefix(&name, tctx->origin, &prefix);
        return (dns_name_totext(&prefix, sub, target));
}

static inline isc_result_t
fromwire_in_a6(ARGS_FROMWIRE) {
        isc_region_t sr;
        unsigned char prefixlen;
        unsigned char octets;
        unsigned char mask;
        dns_name_t name;

        REQUIRE(type == dns_rdatatype_a6);
        REQUIRE(rdclass == dns_rdataclass_in);

        UNUSED(type);
        UNUSED(rdclass);

        dns_decompress_setmethods(dctx, DNS_COMPRESS_NONE);

        isc_buffer_activeregion(source, &sr);
        /*
         * Prefix length.
         */
        if (sr.length < 1)
                return (ISC_R_UNEXPECTEDEND);
        prefixlen = sr.base[0];
        if (prefixlen > 128)
                return (ISC_R_RANGE);
        isc_region_consume(&sr, 1);
        RETERR(isc_mem_tobuffer(target, &prefixlen, 1));
        isc_buffer_forward(source, 1);

        /*
         * Suffix.
         */
        if (prefixlen != 128) {
                octets = 16 - prefixlen / 8;
                if (sr.length < octets)
                        return (ISC_R_UNEXPECTEDEND);
                mask = 0xff >> (prefixlen % 8);
                sr.base[0] &= mask;     /* Ensure pad bits are zero. */
                RETERR(isc_mem_tobuffer(target, sr.base, octets));
                isc_buffer_forward(source, octets);
        }

        if (prefixlen == 0)
                return (ISC_R_SUCCESS);

        dns_name_init(&name, NULL);
        return (dns_name_fromwire(&name, source, dctx, options, target));
}

static inline isc_result_t
towire_in_a6(ARGS_TOWIRE) {
        isc_region_t sr;
        dns_name_t name;
        dns_offsets_t offsets;
        unsigned char prefixlen;
        unsigned char octets;

        REQUIRE(rdata->type == dns_rdatatype_a6);
        REQUIRE(rdata->rdclass == dns_rdataclass_in);
        REQUIRE(rdata->length != 0);

        dns_compress_setmethods(cctx, DNS_COMPRESS_NONE);
        dns_rdata_toregion(rdata, &sr);
        prefixlen = sr.base[0];
        INSIST(prefixlen <= 128);

        octets = 1 + 16 - prefixlen / 8;
        RETERR(isc_mem_tobuffer(target, sr.base, octets));
        isc_region_consume(&sr, octets);

        if (prefixlen == 0)
                return (ISC_R_SUCCESS);

        dns_name_init(&name, offsets);
        dns_name_fromregion(&name, &sr);
        return (dns_name_towire(&name, cctx, target));
}

#endif  /* RDATA_IN_1_A6_38_C */