rdata/generic/opt_41.c

	opt_41.c revision 0c27b3fe77ac1d5094ba3521e8142d9e7973133f
/*
 * Copyright (C) 1998-2002, 2004, 2005, 2007, 2009, 2011-2016  Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/* Reviewed: Thu Mar 16 14:06:44 PST 2000 by gson */

/* RFC2671 */

#ifndef RDATA_GENERIC_OPT_41_C
#define RDATA_GENERIC_OPT_41_C

#define RRTYPE_OPT_ATTRIBUTES (DNS_RDATATYPEATTR_SINGLETON | \
                   DNS_RDATATYPEATTR_META | \
                   DNS_RDATATYPEATTR_NOTQUESTION)

static inline isc_result_t
fromtext_opt(ARGS_FROMTEXT) {
    /*
     * OPT records do not have a text format.
     */

    REQUIRE(type == dns_rdatatype_opt);

    UNUSED(type);
    UNUSED(rdclass);
    UNUSED(lexer);
    UNUSED(origin);
    UNUSED(options);
    UNUSED(target);
    UNUSED(callbacks);

    return (ISC_R_NOTIMPLEMENTED);
}

static inline isc_result_t
totext_opt(ARGS_TOTEXT) {
    isc_region_t r;
    isc_region_t or;
    isc_uint16_t option;
    isc_uint16_t length;
    char buf[sizeof("64000 64000")];

    /*
     * OPT records do not have a text format.
     */

    REQUIRE(rdata->type == dns_rdatatype_opt);

    dns_rdata_toregion(rdata, &r);
    while (r.length > 0) {
        option = uint16_fromregion(&r);
        isc_region_consume(&r, 2);
        length = uint16_fromregion(&r);
        isc_region_consume(&r, 2);
        sprintf(buf, "%u %u", option, length);
        RETERR(str_totext(buf, target));
        INSIST(r.length >= length);
        if (length > 0) {
            if ((tctx->flags & DNS_STYLEFLAG_MULTILINE) != 0)
                RETERR(str_totext(" (", target));
            RETERR(str_totext(tctx->linebreak, target));
            or = r;
            or.length = length;
            if (tctx->width == 0)   /* No splitting */
                RETERR(isc_base64_totext(&or, 60, "", target));
            else
                RETERR(isc_base64_totext(&or, tctx->width - 2,
                             tctx->linebreak,
                             target));
            isc_region_consume(&r, length);
            if ((tctx->flags & DNS_STYLEFLAG_MULTILINE) != 0)
                RETERR(str_totext(" )", target));
        }
        if (r.length > 0)
            RETERR(str_totext(" ", target));
    }

    return (ISC_R_SUCCESS);
}

static inline isc_result_t
fromwire_opt(ARGS_FROMWIRE) {
    isc_region_t sregion;
    isc_region_t tregion;
    isc_uint16_t opt;
    isc_uint16_t length;
    unsigned int total;

    REQUIRE(type == dns_rdatatype_opt);

    UNUSED(type);
    UNUSED(rdclass);
    UNUSED(dctx);
    UNUSED(options);

    isc_buffer_activeregion(source, &sregion);
    total = 0;
    while (sregion.length != 0) {
        if (sregion.length < 4)
            return (ISC_R_UNEXPECTEDEND);
        opt = uint16_fromregion(&sregion);
        isc_region_consume(&sregion, 2);
        length = uint16_fromregion(&sregion);
        isc_region_consume(&sregion, 2);
        total += 4;
        if (sregion.length < length)
            return (ISC_R_UNEXPECTEDEND);
        switch (opt) {
        case DNS_OPT_CLIENT_SUBNET: {
            isc_uint16_t family;
            isc_uint8_t addrlen;
            isc_uint8_t scope;
            isc_uint8_t addrbytes;

            if (length < 4)
                return (DNS_R_OPTERR);
            family = uint16_fromregion(&sregion);
            isc_region_consume(&sregion, 2);
            addrlen = uint8_fromregion(&sregion);
            isc_region_consume(&sregion, 1);
            scope = uint8_fromregion(&sregion);
            isc_region_consume(&sregion, 1);

            if (addrlen == 0U && family != 0U)
                return (DNS_R_OPTERR);

            switch (family) {
            case 0:
                /*
                 * XXXMUKS: In queries and replies, if
                 * FAMILY is set to 0, SOURCE
                 * PREFIX-LENGTH and SCOPE PREFIX-LENGTH
                 * must be 0 and ADDRESS should not be
                 * present as the address and prefix
                 * lengths don't make sense because the
                 * family is unknown.
                 */
                if (addrlen != 0U || scope != 0U)
                    return (DNS_R_OPTERR);
                break;
            case 1:
                if (addrlen > 32U || scope > 32U)
                    return (DNS_R_OPTERR);
                break;
            case 2:
                if (addrlen > 128U || scope > 128U)
                    return (DNS_R_OPTERR);
                break;
            default:
                return (DNS_R_OPTERR);
            }
            addrbytes = (addrlen + 7) / 8;
            if (addrbytes + 4 != length)
                return (DNS_R_OPTERR);

            if (addrbytes != 0U && (addrlen % 8) != 0) {
                isc_uint8_t bits = ~0 << (8 - (addrlen % 8));
                bits &= sregion.base[addrbytes - 1];
                if (bits != sregion.base[addrbytes - 1])
                    return (DNS_R_OPTERR);
            }
            isc_region_consume(&sregion, addrbytes);
            break;
        }
        case DNS_OPT_EXPIRE:
            /*
             * Request has zero length.  Response is 32 bits.
             */
            if (length != 0 && length != 4)
                return (DNS_R_OPTERR);
            isc_region_consume(&sregion, length);
            break;
        case DNS_OPT_COOKIE:
            if (length != 8 && (length < 16 || length > 40))
                return (DNS_R_OPTERR);
            isc_region_consume(&sregion, length);
            break;
        default:
            isc_region_consume(&sregion, length);
            break;
        }
        total += length;
    }

    isc_buffer_activeregion(source, &sregion);
    isc_buffer_availableregion(target, &tregion);
    if (tregion.length < total)
        return (ISC_R_NOSPACE);
    memmove(tregion.base, sregion.base, total);
    isc_buffer_forward(source, total);
    isc_buffer_add(target, total);

    return (ISC_R_SUCCESS);
}

static inline isc_result_t
towire_opt(ARGS_TOWIRE) {

    REQUIRE(rdata->type == dns_rdatatype_opt);

    UNUSED(cctx);

    return (mem_tobuffer(target, rdata->data, rdata->length));
}

static inline int
compare_opt(ARGS_COMPARE) {
    isc_region_t r1;
    isc_region_t r2;

    REQUIRE(rdata1->type == rdata2->type);
    REQUIRE(rdata1->rdclass == rdata2->rdclass);
    REQUIRE(rdata1->type == dns_rdatatype_opt);

    dns_rdata_toregion(rdata1, &r1);
    dns_rdata_toregion(rdata2, &r2);
    return (isc_region_compare(&r1, &r2));
}

static inline isc_result_t
fromstruct_opt(ARGS_FROMSTRUCT) {
    dns_rdata_opt_t *opt = source;
    isc_region_t region;
    isc_uint16_t length;

    REQUIRE(type == dns_rdatatype_opt);
    REQUIRE(source != NULL);
    REQUIRE(opt->common.rdtype == type);
    REQUIRE(opt->common.rdclass == rdclass);
    REQUIRE(opt->options != NULL || opt->length == 0);

    UNUSED(type);
    UNUSED(rdclass);

    region.base = opt->options;
    region.length = opt->length;
    while (region.length >= 4) {
        isc_region_consume(&region, 2); /* opt */
        length = uint16_fromregion(&region);
        isc_region_consume(&region, 2);
        if (region.length < length)
            return (ISC_R_UNEXPECTEDEND);
        isc_region_consume(&region, length);
    }
    if (region.length != 0)
        return (ISC_R_UNEXPECTEDEND);

    return (mem_tobuffer(target, opt->options, opt->length));
}

static inline isc_result_t
tostruct_opt(ARGS_TOSTRUCT) {
    dns_rdata_opt_t *opt = target;
    isc_region_t r;

    REQUIRE(rdata->type == dns_rdatatype_opt);
    REQUIRE(target != NULL);

    opt->common.rdclass = rdata->rdclass;
    opt->common.rdtype = rdata->type;
    ISC_LINK_INIT(&opt->common, link);

    dns_rdata_toregion(rdata, &r);
    opt->length = r.length;
    opt->options = mem_maybedup(mctx, r.base, r.length);
    if (opt->options == NULL)
        return (ISC_R_NOMEMORY);

    opt->offset = 0;
    opt->mctx = mctx;
    return (ISC_R_SUCCESS);
}

static inline void
freestruct_opt(ARGS_FREESTRUCT) {
    dns_rdata_opt_t *opt = source;

    REQUIRE(source != NULL);
    REQUIRE(opt->common.rdtype == dns_rdatatype_opt);

    if (opt->mctx == NULL)
        return;

    if (opt->options != NULL)
        isc_mem_free(opt->mctx, opt->options);
    opt->mctx = NULL;
}

static inline isc_result_t
additionaldata_opt(ARGS_ADDLDATA) {
    REQUIRE(rdata->type == dns_rdatatype_opt);

    UNUSED(rdata);
    UNUSED(add);
    UNUSED(arg);

    return (ISC_R_SUCCESS);
}

static inline isc_result_t
digest_opt(ARGS_DIGEST) {

    /*
     * OPT records are not digested.
     */

    REQUIRE(rdata->type == dns_rdatatype_opt);

    UNUSED(rdata);
    UNUSED(digest);
    UNUSED(arg);

    return (ISC_R_NOTIMPLEMENTED);
}

static inline isc_boolean_t
checkowner_opt(ARGS_CHECKOWNER) {

    REQUIRE(type == dns_rdatatype_opt);

    UNUSED(type);
    UNUSED(rdclass);
    UNUSED(wildcard);

    return (dns_name_equal(name, dns_rootname));
}

static inline isc_boolean_t
checknames_opt(ARGS_CHECKNAMES) {

    REQUIRE(rdata->type == dns_rdatatype_opt);

    UNUSED(rdata);
    UNUSED(owner);
    UNUSED(bad);

    return (ISC_TRUE);
}

static inline int
casecompare_opt(ARGS_COMPARE) {
    return (compare_opt(rdata1, rdata2));
}

isc_result_t
dns_rdata_opt_first(dns_rdata_opt_t *opt) {

    REQUIRE(opt != NULL);
    REQUIRE(opt->common.rdtype == dns_rdatatype_opt);
    REQUIRE(opt->options != NULL || opt->length == 0);

    if (opt->length == 0)
        return (ISC_R_NOMORE);

    opt->offset = 0;
    return (ISC_R_SUCCESS);
}

isc_result_t
dns_rdata_opt_next(dns_rdata_opt_t *opt) {
    isc_region_t r;
    isc_uint16_t length;

    REQUIRE(opt != NULL);
    REQUIRE(opt->common.rdtype == dns_rdatatype_opt);
    REQUIRE(opt->options != NULL && opt->length != 0);
    REQUIRE(opt->offset < opt->length);

    INSIST(opt->offset + 4 <= opt->length);
    r.base = opt->options + opt->offset + 2;
    r.length = opt->length - opt->offset - 2;
    length = uint16_fromregion(&r);
    INSIST(opt->offset + 4 + length <= opt->length);
    opt->offset = opt->offset + 4 + length;
    if (opt->offset == opt->length)
        return (ISC_R_NOMORE);
    return (ISC_R_SUCCESS);
}

isc_result_t
dns_rdata_opt_current(dns_rdata_opt_t *opt, dns_rdata_opt_opcode_t *opcode) {
    isc_region_t r;

    REQUIRE(opt != NULL);
    REQUIRE(opcode != NULL);
    REQUIRE(opt->common.rdtype == dns_rdatatype_opt);
    REQUIRE(opt->options != NULL);
    REQUIRE(opt->offset < opt->length);

    INSIST(opt->offset + 4 <= opt->length);
    r.base = opt->options + opt->offset;
    r.length = opt->length - opt->offset;

    opcode->opcode = uint16_fromregion(&r);
    isc_region_consume(&r, 2);
    opcode->length = uint16_fromregion(&r);
    isc_region_consume(&r, 2);
    opcode->data = r.base;
    INSIST(opt->offset + 4 + opcode->length <= opt->length);

    return (ISC_R_SUCCESS);
}

#endif  /* RDATA_GENERIC_OPT_41_C */