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ecs.c revision 1.1.2.2 
      1  1.1.2.2  martin /*	$NetBSD: ecs.c,v 1.1.2.2 2024/02/24 13:06:57 martin Exp $	*/
      2  1.1.2.2  martin 
      3  1.1.2.2  martin /*
      4  1.1.2.2  martin  * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
      5  1.1.2.2  martin  *
      6  1.1.2.2  martin  * SPDX-License-Identifier: MPL-2.0
      7  1.1.2.2  martin  *
      8  1.1.2.2  martin  * This Source Code Form is subject to the terms of the Mozilla Public
      9  1.1.2.2  martin  * License, v. 2.0. If a copy of the MPL was not distributed with this
     10  1.1.2.2  martin  * file, you can obtain one at https://mozilla.org/MPL/2.0/.
     11  1.1.2.2  martin  *
     12  1.1.2.2  martin  * See the COPYRIGHT file distributed with this work for additional
     13  1.1.2.2  martin  * information regarding copyright ownership.
     14  1.1.2.2  martin  */
     15  1.1.2.2  martin 
     16  1.1.2.2  martin /*! \file */
     17  1.1.2.2  martin 
     18  1.1.2.2  martin #include <string.h>
     19  1.1.2.2  martin 
     20  1.1.2.2  martin #include <isc/buffer.h>
     21  1.1.2.2  martin #include <isc/mem.h>
     22  1.1.2.2  martin #include <isc/netaddr.h>
     23  1.1.2.2  martin #include <isc/print.h>
     24  1.1.2.2  martin #include <isc/util.h>
     25  1.1.2.2  martin 
     26  1.1.2.2  martin #include <dns/ecs.h>
     27  1.1.2.2  martin #include <dns/nsec.h>
     28  1.1.2.2  martin #include <dns/rbt.h>
     29  1.1.2.2  martin #include <dns/rdata.h>
     30  1.1.2.2  martin #include <dns/rdatatype.h>
     31  1.1.2.2  martin #include <dns/result.h>
     32  1.1.2.2  martin #include <dns/types.h>
     33  1.1.2.2  martin 
     34  1.1.2.2  martin void
     35  1.1.2.2  martin dns_ecs_init(dns_ecs_t *ecs) {
     36  1.1.2.2  martin 	isc_netaddr_unspec(&ecs->addr);
     37  1.1.2.2  martin 	ecs->source = 0;
     38  1.1.2.2  martin 	ecs->scope = 0xff;
     39  1.1.2.2  martin }
     40  1.1.2.2  martin 
     41  1.1.2.2  martin bool
     42  1.1.2.2  martin dns_ecs_equals(const dns_ecs_t *ecs1, const dns_ecs_t *ecs2) {
     43  1.1.2.2  martin 	const unsigned char *addr1, *addr2;
     44  1.1.2.2  martin 	uint8_t mask;
     45  1.1.2.2  martin 	size_t alen;
     46  1.1.2.2  martin 
     47  1.1.2.2  martin 	REQUIRE(ecs1 != NULL && ecs2 != NULL);
     48  1.1.2.2  martin 
     49  1.1.2.2  martin 	if (ecs1->source != ecs2->source ||
     50  1.1.2.2  martin 	    ecs1->addr.family != ecs2->addr.family)
     51  1.1.2.2  martin 	{
     52  1.1.2.2  martin 		return (false);
     53  1.1.2.2  martin 	}
     54  1.1.2.2  martin 
     55  1.1.2.2  martin 	alen = (ecs1->source + 7) / 8;
     56  1.1.2.2  martin 	if (alen == 0) {
     57  1.1.2.2  martin 		return (true);
     58  1.1.2.2  martin 	}
     59  1.1.2.2  martin 
     60  1.1.2.2  martin 	switch (ecs1->addr.family) {
     61  1.1.2.2  martin 	case AF_INET:
     62  1.1.2.2  martin 		INSIST(alen <= 4);
     63  1.1.2.2  martin 		addr1 = (const unsigned char *)&ecs1->addr.type.in;
     64  1.1.2.2  martin 		addr2 = (const unsigned char *)&ecs2->addr.type.in;
     65  1.1.2.2  martin 		break;
     66  1.1.2.2  martin 	case AF_INET6:
     67  1.1.2.2  martin 		INSIST(alen <= 16);
     68  1.1.2.2  martin 		addr1 = (const unsigned char *)&ecs1->addr.type.in6;
     69  1.1.2.2  martin 		addr2 = (const unsigned char *)&ecs2->addr.type.in6;
     70  1.1.2.2  martin 		break;
     71  1.1.2.2  martin 	default:
     72  1.1.2.2  martin 		UNREACHABLE();
     73  1.1.2.2  martin 	}
     74  1.1.2.2  martin 
     75  1.1.2.2  martin 	/*
     76  1.1.2.2  martin 	 * Compare all octets except the final octet of the address
     77  1.1.2.2  martin 	 * prefix.
     78  1.1.2.2  martin 	 */
     79  1.1.2.2  martin 	if (alen > 1 && memcmp(addr1, addr2, alen - 1) != 0) {
     80  1.1.2.2  martin 		return (false);
     81  1.1.2.2  martin 	}
     82  1.1.2.2  martin 
     83  1.1.2.2  martin 	/*
     84  1.1.2.2  martin 	 * It should not be necessary to mask the final octet; all
     85  1.1.2.2  martin 	 * bits past the source prefix length are supposed to be 0.
     86  1.1.2.2  martin 	 * However, it seems prudent not to omit them from the
     87  1.1.2.2  martin 	 * comparison anyway.
     88  1.1.2.2  martin 	 */
     89  1.1.2.2  martin 	mask = (~0U << (8 - (ecs1->source % 8))) & 0xff;
     90  1.1.2.2  martin 	if (mask == 0) {
     91  1.1.2.2  martin 		mask = 0xff;
     92  1.1.2.2  martin 	}
     93  1.1.2.2  martin 
     94  1.1.2.2  martin 	if ((addr1[alen - 1] & mask) != (addr2[alen - 1] & mask)) {
     95  1.1.2.2  martin 		return (false);
     96  1.1.2.2  martin 	}
     97  1.1.2.2  martin 
     98  1.1.2.2  martin 	return (true);
     99  1.1.2.2  martin }
    100  1.1.2.2  martin 
    101  1.1.2.2  martin void
    102  1.1.2.2  martin dns_ecs_format(const dns_ecs_t *ecs, char *buf, size_t size) {
    103  1.1.2.2  martin 	size_t len;
    104  1.1.2.2  martin 	char *p;
    105  1.1.2.2  martin 
    106  1.1.2.2  martin 	REQUIRE(ecs != NULL);
    107  1.1.2.2  martin 	REQUIRE(buf != NULL);
    108  1.1.2.2  martin 	REQUIRE(size >= DNS_ECS_FORMATSIZE);
    109  1.1.2.2  martin 
    110  1.1.2.2  martin 	isc_netaddr_format(&ecs->addr, buf, size);
    111  1.1.2.2  martin 	len = strlen(buf);
    112  1.1.2.2  martin 	p = buf + len;
    113  1.1.2.2  martin 	snprintf(p, size - len, "/%d/%d", ecs->source,
    114  1.1.2.2  martin 		 ecs->scope == 0xff ? 0 : ecs->scope);
    115  1.1.2.2  martin }
    116