/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 2022 Florian Obser <florian@openbsd.org>
 *
 * 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: svcb_64.c,v 1.2 2024/10/31 07:40:34 otto Exp $ */

/* draft-ietf-dnsop-svcb-https-10, based on srv_33.c */

#ifndef RDATA_IN_1_SVCB_64_C
#define RDATA_IN_1_SVCB_64_C

#define SVC_PARAM_MANDATORY     0
#define SVC_PARAM_ALPN          1
#define SVC_PARAM_NO_DEF_ALPN   2
#define SVC_PARAM_PORT          3
#define SVC_PARAM_IPV4HINT      4
#define SVC_PARAM_ECH           5
#define SVC_PARAM_IPV6HINT      6
#define SVC_PARAM_DOHPATH       7

static inline const char*
svc_param_key_to_text(uint16_t key)
{
        static char buf[sizeof "key65535"];

        switch (key) {
        case SVC_PARAM_MANDATORY:
                return ("mandatory");
        case SVC_PARAM_ALPN:
                return ("alpn");
        case SVC_PARAM_NO_DEF_ALPN:
                return ("no-default-alpn");
        case SVC_PARAM_PORT:
                return ("port");
        case SVC_PARAM_IPV4HINT:
                return ("ipv4hint");
        case SVC_PARAM_ECH:
                return ("ech");
        case SVC_PARAM_IPV6HINT:
                return ("ipv6hint");
        case SVC_PARAM_DOHPATH:
                return ("dohpath");
        default:
                snprintf(buf, sizeof buf, "key%u", key);
                return (buf);
        }
}

static inline isc_result_t
totext_in_svcb_https(ARGS_TOTEXT) {
        isc_region_t region;
        dns_name_t name;
        dns_name_t prefix;
        int sub;
        char buf[sizeof "xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255"];
        unsigned short num;

        dns_name_init(&name, NULL);
        dns_name_init(&prefix, NULL);

        /*
         * Priority.
         */
        dns_rdata_toregion(rdata, &region);
        num = uint16_fromregion(&region);
        isc_region_consume(&region, 2);
        snprintf(buf, sizeof buf, "%u", num);
        RETERR(isc_str_tobuffer(buf, target));
        RETERR(isc_str_tobuffer(" ", target));

        /*
         * Target.
         */
        dns_name_fromregion(&name, &region);
        isc_region_consume(&region, name_length(&name));
        sub = name_prefix(&name, tctx->origin, &prefix);
        RETERR(dns_name_totext(&prefix, sub, target));

        while (region.length > 0) {
                isc_region_t val_region;
                uint16_t svc_param_key, svc_param_value_len, man_key, port;

                RETERR(isc_str_tobuffer(" ", target));

                svc_param_key = uint16_fromregion(&region);
                isc_region_consume(&region, 2);

                svc_param_value_len = uint16_fromregion(&region);
                isc_region_consume(&region, 2);

                RETERR(isc_str_tobuffer(svc_param_key_to_text(svc_param_key),
                    target));

                val_region = region;
                val_region.length = svc_param_value_len;

                isc_region_consume(&region, svc_param_value_len);

                switch (svc_param_key) {
                case SVC_PARAM_MANDATORY:
                        INSIST(val_region.length % 2 == 0);
                        RETERR(isc_str_tobuffer("=", target));
                        while (val_region.length > 0) {
                                man_key = uint16_fromregion(&val_region);
                                isc_region_consume(&val_region, 2);
                                RETERR(isc_str_tobuffer(svc_param_key_to_text(
                                    man_key), target));
                                if (val_region.length != 0)
                                        RETERR(isc_str_tobuffer(",", target));
                        }
                        break;
                case SVC_PARAM_ALPN:
                        RETERR(isc_str_tobuffer("=\"", target));
                        while (val_region.length > 0) {
                                txt_totext(&val_region, 0, target);
                                if (val_region.length != 0)
                                        RETERR(isc_str_tobuffer(",", target));
                        }
                        RETERR(isc_str_tobuffer("\"", target));
                        break;
                case SVC_PARAM_NO_DEF_ALPN:
                        INSIST(val_region.length == 0);
                        break;
                case SVC_PARAM_PORT:
                        INSIST(val_region.length == 2);
                        RETERR(isc_str_tobuffer("=", target));
                        port = uint16_fromregion(&val_region);
                        isc_region_consume(&val_region, 2);
                        snprintf(buf, sizeof buf, "%u", port);
                        RETERR(isc_str_tobuffer(buf, target));
                        break;
                case SVC_PARAM_IPV4HINT:
                        INSIST(val_region.length % 4 == 0);
                        RETERR(isc_str_tobuffer("=", target));
                        while (val_region.length > 0) {
                                inet_ntop(AF_INET, val_region.base, buf,
                                    sizeof buf);
                                RETERR(isc_str_tobuffer(buf, target));
                                isc_region_consume(&val_region, 4);
                                if (val_region.length != 0)
                                        RETERR(isc_str_tobuffer(",", target));
                        }
                        break;
                case SVC_PARAM_ECH:
                        RETERR(isc_str_tobuffer("=", target));
                        RETERR(isc_base64_totext(&val_region, 0, "", target));
                        break;
                case SVC_PARAM_IPV6HINT:
                        INSIST(val_region.length % 16 == 0);
                        RETERR(isc_str_tobuffer("=", target));
                        while (val_region.length > 0) {
                                inet_ntop(AF_INET6, val_region.base, buf,
                                    sizeof buf);
                                RETERR(isc_str_tobuffer(buf, target));
                                isc_region_consume(&val_region, 16);
                                if (val_region.length != 0)
                                        RETERR(isc_str_tobuffer(",", target));
                        }
                        break;
                case SVC_PARAM_DOHPATH:
                        RETERR(isc_str_tobuffer("=", target));
                        RETERR(multitxt_totext(&val_region, target));
                        break;
                default:
                        RETERR(isc_str_tobuffer("=", target));
                        RETERR(multitxt_totext(&val_region, target));
                        break;
                }
        }
        return (ISC_R_SUCCESS);
}

static inline isc_result_t
totext_in_svcb(ARGS_TOTEXT) {
        REQUIRE(rdata->type == dns_rdatatype_svcb);
        REQUIRE(rdata->rdclass == dns_rdataclass_in);
        REQUIRE(rdata->length != 0);

        return (totext_in_svcb_https(rdata, tctx, target));
}

static inline isc_result_t
fromwire_in_svcb_https(ARGS_FROMWIRE) {
        dns_name_t name;
        isc_region_t sr;
        unsigned int svc_param_value_len;

        UNUSED(type);
        UNUSED(rdclass);

        dns_decompress_setmethods(dctx, DNS_COMPRESS_NONE);

        dns_name_init(&name, NULL);

        /*
         * SvcPriority.
         */
        isc_buffer_activeregion(source, &sr);
        if (sr.length < 2)
                return (ISC_R_UNEXPECTEDEND);
        RETERR(isc_mem_tobuffer(target, sr.base, 2));
        isc_buffer_forward(source, 2);

        /*
         * TargetName.
         */
        RETERR(dns_name_fromwire(&name, source, dctx, options, target));

        isc_buffer_activeregion(source, &sr);
        while (sr.length > 0) {
                /*
                 * SvcParamKey.
                 */
                if (sr.length < 2)
                        return (ISC_R_UNEXPECTEDEND);

                RETERR(isc_mem_tobuffer(target, sr.base, 2));
                isc_region_consume(&sr, 2);
                isc_buffer_forward(source, 2);

                /*
                 * SvcParamValue length.
                 */
                if (sr.length < 2)
                        return (ISC_R_UNEXPECTEDEND);

                RETERR(isc_mem_tobuffer(target, sr.base, 2));
                svc_param_value_len = uint16_fromregion(&sr);
                isc_region_consume(&sr, 2);
                isc_buffer_forward(source, 2);

                if (sr.length < svc_param_value_len)
                        return (ISC_R_UNEXPECTEDEND);

                RETERR(isc_mem_tobuffer(target, sr.base, svc_param_value_len));
                isc_region_consume(&sr, svc_param_value_len);
                isc_buffer_forward(source, svc_param_value_len);
        }

        return (ISC_R_SUCCESS);
}

static inline isc_result_t
fromwire_in_svcb(ARGS_FROMWIRE) {
        REQUIRE(type == dns_rdatatype_svcb);
        REQUIRE(rdclass == dns_rdataclass_in);
        return (fromwire_in_svcb_https(rdclass, type, source, dctx, options,
            target));
}

static inline isc_result_t
towire_in_svcb_https(ARGS_TOWIRE) {
        dns_name_t name;
        dns_offsets_t offsets;
        isc_region_t sr;

        dns_compress_setmethods(cctx, DNS_COMPRESS_NONE);

        /*
         * SvcPriority.
         */
        dns_rdata_toregion(rdata, &sr);
        RETERR(isc_mem_tobuffer(target, sr.base, 2));
        isc_region_consume(&sr, 2);

        /*
         * TargetName.
         */
        dns_name_init(&name, offsets);
        dns_name_fromregion(&name, &sr);
        RETERR(dns_name_towire(&name, cctx, target));
        isc_region_consume(&sr, name_length(&name));

        /*
         * SvcParams.
         */
        return (isc_mem_tobuffer(target, sr.base, sr.length));
}

static inline isc_result_t
towire_in_svcb(ARGS_TOWIRE) {
        REQUIRE(rdata->type == dns_rdatatype_svcb);
        REQUIRE(rdata->length != 0);

        return (towire_in_svcb_https(rdata, cctx, target));
}
#endif  /* RDATA_IN_1_SVCB_64_C */