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/* $OpenBSD: dns64_synth.c,v 1.1 2021/01/24 18:29:15 florian Exp $ */
/*
* dns64/dns64.h - DNS64 module
*
* Copyright (c) 2009, Viagénie. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright (c) 2021 Florian Obser <florian@openbsd.org>
*
* Permission to use, copy, modify, and 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 THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR 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.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <net/route.h>
#include <string.h>
#include "libunbound/config.h"
#include "libunbound/util/regional.h"
#include "libunbound/util/data/msgencode.h"
#include "libunbound/util/data/msgparse.h"
#include "libunbound/util/data/msgreply.h"
#include "log.h"
#include "unwind.h"
#include "frontend.h"
#include "dns64_synth.h"
extern struct dns64_prefix *dns64_prefixes;
extern int dns64_prefix_count;
static void
synthesize_aaaa(const struct in6_addr *in6, int prefixlen, const uint8_t *a,
size_t a_len, uint8_t *aaaa, size_t aaaa_len)
{
size_t i, pos;
memcpy(aaaa, in6->s6_addr, sizeof(in6->s6_addr));
for (i = 0, pos = prefixlen / 8; i < a_len && pos < aaaa_len;
i++, pos++) {
if (pos == 8)
aaaa[pos++] = 0;
aaaa[pos] = a[i];
}
}
/*
* Copied from unbound/dns64/dns64.c and slightly extended to work with more
* than one IPv6 prefix.
*/
void
dns64_synth_aaaa_data(const struct ub_packed_rrset_key* fk, const struct
packed_rrset_data* fd, struct ub_packed_rrset_key *dk, struct
packed_rrset_data **dd_out, struct regional *region)
{
struct packed_rrset_data *dd;
size_t i, pos;
int j;
/*
* Create synthesized AAAA RR set data. We need to allocated extra
* memory for the RRs themselves. Each RR has a length, TTL, pointer to
* wireformat data, 2 bytes of data length, and 16 bytes of IPv6
* address.
*/
if(fd->count > RR_COUNT_MAX) {
*dd_out = NULL;
return; /* integer overflow protection in alloc */
}
if (!(dd = *dd_out = regional_alloc(region, sizeof(struct
packed_rrset_data) + fd->count * dns64_prefix_count *
(sizeof(size_t) + sizeof(time_t) + sizeof(uint8_t*) + 2 + 16)))) {
log_warnx("out of memory");
return;
}
/* Copy attributes from A RR set. */
dd->ttl = fd->ttl;
dd->count = fd->count * dns64_prefix_count;
dd->rrsig_count = 0;
dd->trust = fd->trust;
dd->security = fd->security;
/* Synthesize AAAA records. Adjust pointers in structure. */
dd->rr_len = (size_t*)((uint8_t*)dd + sizeof(struct packed_rrset_data));
dd->rr_data = (uint8_t**)&dd->rr_len[dd->count];
dd->rr_ttl = (time_t*)&dd->rr_data[dd->count];
for(i = 0, pos = 0; i < fd->count; ++i) {
if (fd->rr_len[i] != 6 || fd->rr_data[i][0] != 0 ||
fd->rr_data[i][1] != 4) {
*dd_out = NULL;
return;
}
for (j = 0; j < dns64_prefix_count; j++, pos++) {
dd->rr_len[pos] = 18;
dd->rr_ttl[pos] = fd->rr_ttl[i];
dd->rr_data[pos] = (uint8_t*)&dd->rr_ttl[dd->count] +
18 * pos;
dd->rr_data[pos][0] = 0;
dd->rr_data[pos][1] = 16;
synthesize_aaaa(&dns64_prefixes[j].in6,
dns64_prefixes[j].prefixlen, &fd->rr_data[i][2],
fd->rr_len[i]-2, &dd->rr_data[pos][2],
dd->rr_len[pos]-2);
}
}
/*
* Create synthesized AAAA RR set key. This is mostly just bookkeeping,
* nothing interesting here.
*/
if(!dk) {
log_warnx("no key");
*dd_out = NULL;
return;
}
dk->rk.dname = (uint8_t*)regional_alloc_init(region, fk->rk.dname,
fk->rk.dname_len);
if(!dk->rk.dname) {
log_warnx("out of memory");
*dd_out = NULL;
return;
}
dk->rk.type = htons(LDNS_RR_TYPE_AAAA);
memset(&dk->entry, 0, sizeof(dk->entry));
dk->entry.key = dk;
dk->entry.hash = rrset_key_hash(&dk->rk);
dk->entry.data = dd;
}
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