dns64.c revision 1e442d19949b84d448742672e2ed8cab1177abb6
/*
* Copyright (C) 2010 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: dns64.c,v 1.4 2010/12/09 04:01:43 marka Exp $ */
#include <config.h>
#include <isc/list.h>
#include <isc/mem.h>
#include <isc/netaddr.h>
#include <isc/string.h>
#include <isc/util.h>
#include <dns/acl.h>
#include <dns/dns64.h>
#include <dns/rdata.h>
#include <dns/rdataset.h>
#include <dns/result.h>
struct dns_dns64 {
unsigned char bits[16]; /*
* Prefix + suffix bits.
*/
dns_acl_t * clients; /*
* Which clients get mapped
* addresses.
*/
dns_acl_t * mapped; /*
* IPv4 addresses to be mapped.
*/
dns_acl_t * excluded; /*
* IPv6 addresses that are
* treated as not existing.
*/
unsigned int prefixlen; /*
* Start of mapped address.
*/
unsigned int flags;
isc_mem_t * mctx;
ISC_LINK(dns_dns64_t) link;
};
isc_result_t
dns_dns64_create(isc_mem_t *mctx, isc_netaddr_t *prefix,
unsigned int prefixlen, isc_netaddr_t *suffix,
dns_acl_t *clients, dns_acl_t *mapped, dns_acl_t *excluded,
unsigned int flags, dns_dns64_t **dns64)
{
dns_dns64_t *new;
unsigned int nbytes = 16;
REQUIRE(prefix != NULL && prefix->family == AF_INET6);
/* Legal prefix lengths from draft-ietf-behave-address-format-04. */
REQUIRE(prefixlen == 32 || prefixlen == 40 || prefixlen == 48 ||
prefixlen == 56 || prefixlen == 64 || prefixlen == 96);
REQUIRE(isc_netaddr_prefixok(prefix, prefixlen) == ISC_R_SUCCESS);
REQUIRE(dns64 != NULL && *dns64 == NULL);
if (suffix != NULL) {
static const unsigned char zeros[16];
REQUIRE(prefix->family == AF_INET6);
nbytes = prefixlen / 8 + 4;
/* Bits 64-71 are zeros. draft-ietf-behave-address-format-04 */
if (prefixlen >= 32 && prefixlen <= 64)
nbytes++;
REQUIRE(memcmp(suffix->type.in6.s6_addr, zeros, nbytes) == 0);
}
new = isc_mem_get(mctx, sizeof(dns_dns64_t));
if (new == NULL)
return (ISC_R_NOMEMORY);
memset(new->bits, 0, sizeof(new->bits));
memcpy(new->bits, prefix->type.in6.s6_addr, prefixlen / 8);
if (suffix != NULL)
memcpy(new->bits + nbytes, suffix->type.in6.s6_addr + nbytes,
16 - nbytes);
new->clients = NULL;
if (clients != NULL)
dns_acl_attach(clients, &new->clients);
new->mapped = NULL;
if (mapped != NULL)
dns_acl_attach(mapped, &new->mapped);
new->excluded = NULL;
if (excluded != NULL)
dns_acl_attach(excluded, &new->excluded);
new->prefixlen = prefixlen;
new->flags = flags;
ISC_LINK_INIT(new, link);
new->mctx = NULL;
isc_mem_attach(mctx, &new->mctx);
*dns64 = new;
return (ISC_R_SUCCESS);
};
void
dns_dns64_destroy(dns_dns64_t **dns64p) {
dns_dns64_t *dns64;
REQUIRE(dns64p != NULL && *dns64p != NULL);
dns64 = *dns64p;
*dns64p = NULL;
REQUIRE(!ISC_LINK_LINKED(dns64, link));
if (dns64->clients != NULL)
dns_acl_detach(&dns64->clients);
if (dns64->mapped != NULL)
dns_acl_detach(&dns64->mapped);
if (dns64->excluded != NULL)
dns_acl_detach(&dns64->excluded);
isc_mem_putanddetach(&dns64->mctx, dns64, sizeof(*dns64));
}
isc_result_t
dns_dns64_aaaafroma(const dns_dns64_t *dns64, const isc_netaddr_t *reqaddr,
const dns_name_t *reqsigner, const dns_aclenv_t *env,
unsigned int flags, unsigned char *a, unsigned char *aaaa)
{
unsigned int nbytes, i;
isc_result_t result;
int match;
if ((dns64->flags & DNS_DNS64_RECURSIVE_ONLY) != 0 &&
(flags & DNS_DNS64_RECURSIVE) == 0)
return (DNS_R_DISALLOWED);
if ((dns64->flags & DNS_DNS64_BREAK_DNSSEC) == 0 &&
(flags & DNS_DNS64_DNSSEC) != 0)
return (DNS_R_DISALLOWED);
if (dns64->clients != NULL) {
result = dns_acl_match(reqaddr, reqsigner, dns64->clients, env,
&match, NULL);
if (result != ISC_R_SUCCESS)
return (result);
if (match <= 0)
return (DNS_R_DISALLOWED);
}
if (dns64->mapped != NULL) {
struct in_addr ina;
isc_netaddr_t netaddr;
memcpy(&ina.s_addr, a, 4);
isc_netaddr_fromin(&netaddr, &ina);
result = dns_acl_match(&netaddr, NULL, dns64->mapped, env,
&match, NULL);
if (result != ISC_R_SUCCESS)
return (result);
if (match <= 0)
return (DNS_R_DISALLOWED);
}
nbytes = dns64->prefixlen / 8;
INSIST(nbytes <= 12);
/* Copy prefix. */
memcpy(aaaa, dns64->bits, nbytes);
if (nbytes == 8)
aaaa[nbytes++] = 0;
/* Copy mapped address. */
for (i = 0; i < 4U; i++) {
aaaa[nbytes++] = a[i];
/* Bits 64-71 are zeros. draft-ietf-behave-address-format-04 */
if (nbytes == 8)
aaaa[nbytes++] = 0;
}
/* Copy suffix. */
memcpy(aaaa + nbytes, dns64->bits + nbytes, 16 - nbytes);
return (ISC_R_SUCCESS);
}
dns_dns64_t *
dns_dns64_next(dns_dns64_t *dns64) {
dns64 = ISC_LIST_NEXT(dns64, link);
return (dns64);
}
void
dns_dns64_append(dns_dns64list_t *list, dns_dns64_t *dns64) {
ISC_LIST_APPEND(*list, dns64, link);
}
void
dns_dns64_unlink(dns_dns64list_t *list, dns_dns64_t *dns64) {
ISC_LIST_UNLINK(*list, dns64, link);
}
isc_boolean_t
dns_dns64_aaaaok(const dns_dns64_t *dns64, const isc_netaddr_t *reqaddr,
const dns_name_t *reqsigner, const dns_aclenv_t *env,
unsigned int flags, dns_rdataset_t *rdataset,
isc_boolean_t *aaaaok, size_t aaaaoklen)
{
struct in6_addr in6;
isc_netaddr_t netaddr;
isc_result_t result;
int match;
isc_boolean_t answer = ISC_FALSE;
isc_boolean_t found = ISC_FALSE;
unsigned int i, ok;
REQUIRE(rdataset != NULL);
REQUIRE(rdataset->type == dns_rdatatype_aaaa);
REQUIRE(rdataset->rdclass == dns_rdataclass_in);
if (aaaaok != NULL)
REQUIRE(aaaaoklen == dns_rdataset_count(rdataset));
for (;dns64 != NULL; dns64 = ISC_LIST_NEXT(dns64, link)) {
if ((dns64->flags & DNS_DNS64_RECURSIVE_ONLY) != 0 &&
(flags & DNS_DNS64_RECURSIVE) == 0)
continue;
if ((dns64->flags & DNS_DNS64_BREAK_DNSSEC) == 0 &&
(flags & DNS_DNS64_DNSSEC) != 0)
continue;
/*
* Work out if this dns64 structure applies to this client.
*/
if (dns64->clients != NULL) {
result = dns_acl_match(reqaddr, reqsigner,
dns64->clients, env,
&match, NULL);
if (result != ISC_R_SUCCESS)
continue;
if (match <= 0)
continue;
}
if (!found && aaaaok != NULL) {
for (i = 0; i < aaaaoklen; i++)
aaaaok[i] = ISC_FALSE;
}
found = ISC_TRUE;
/*
* If we are not excluding any addresses then any AAAA
* will do.
*/
if (dns64->excluded == NULL) {
answer = ISC_TRUE;
for (i = 0; i < aaaaoklen; i++)
aaaaok[i] = ISC_TRUE;
goto done;
}
i = 0; ok = 0;
for (result = dns_rdataset_first(rdataset);
result == ISC_R_SUCCESS;
result = dns_rdataset_next(rdataset)) {
dns_rdata_t rdata = DNS_RDATA_INIT;
if (aaaaok == NULL || !aaaaok[i]) {
dns_rdataset_current(rdataset, &rdata);
memcpy(&in6.s6_addr, rdata.data, 16);
isc_netaddr_fromin6(&netaddr, &in6);
result = dns_acl_match(&netaddr, NULL,
dns64->excluded,
env, &match, NULL);
if (result == ISC_R_SUCCESS && match <= 0) {
answer = ISC_TRUE;
if (aaaaok == NULL)
goto done;
aaaaok[i] = ISC_TRUE;
ok++;
}
} else
ok++;
i++;
}
/*
* Are all addresses ok?
*/
if (aaaaok != NULL && ok == aaaaoklen)
goto done;
}
done:
if (!found && aaaaok != NULL) {
for (i = 0; i < aaaaoklen; i++)
aaaaok[i] = ISC_TRUE;
}
return (found ? answer : ISC_TRUE);
}