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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2014 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include "resolved-dns-answer.h"
#include "resolved-dns-domain.h"
DnsAnswer *dns_answer_new(unsigned n) {
DnsAnswer *a;
assert(n > 0);
a = malloc0(offsetof(DnsAnswer, rrs) + sizeof(DnsResourceRecord*) * n);
if (!a)
return NULL;
a->n_ref = 1;
a->n_allocated = n;
return a;
}
DnsAnswer *dns_answer_ref(DnsAnswer *a) {
if (!a)
return NULL;
assert(a->n_ref > 0);
a->n_ref++;
return a;
}
DnsAnswer *dns_answer_unref(DnsAnswer *a) {
if (!a)
return NULL;
assert(a->n_ref > 0);
if (a->n_ref == 1) {
unsigned i;
for (i = 0; i < a->n_rrs; i++)
dns_resource_record_unref(a->rrs[i]);
free(a);
} else
a->n_ref--;
return NULL;
}
int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr) {
unsigned i;
int r;
assert(a);
assert(rr);
for (i = 0; i < a->n_rrs; i++) {
r = dns_resource_record_equal(a->rrs[i], rr);
if (r < 0)
return r;
if (r > 0) {
/* Entry already exists, keep the entry with
* the higher RR, or the one with TTL 0 */
if (rr->ttl == 0 || (rr->ttl > a->rrs[i]->ttl && a->rrs[i]->ttl != 0)) {
dns_resource_record_ref(rr);
dns_resource_record_unref(a->rrs[i]);
a->rrs[i] = rr;
}
return 0;
}
}
if (a->n_rrs >= a->n_allocated)
return -ENOSPC;
a->rrs[a->n_rrs++] = dns_resource_record_ref(rr);
return 1;
}
int dns_answer_contains(DnsAnswer *a, DnsResourceKey *key) {
unsigned i;
int r;
assert(a);
assert(key);
for (i = 0; i < a->n_rrs; i++) {
r = dns_resource_key_match_rr(key, a->rrs[i]);
if (r < 0)
return r;
if (r > 0)
return 1;
}
return 0;
}
int dns_answer_find_soa(DnsAnswer *a, DnsResourceKey *key, DnsResourceRecord **ret) {
unsigned i;
assert(a);
assert(key);
assert(ret);
/* For a SOA record we can never find a matching SOA record */
if (key->type == DNS_TYPE_SOA)
return 0;
for (i = 0; i < a->n_rrs; i++) {
if (a->rrs[i]->key->class != DNS_CLASS_IN)
continue;
if (a->rrs[i]->key->type != DNS_TYPE_SOA)
continue;
if (dns_name_endswith(DNS_RESOURCE_KEY_NAME(key), DNS_RESOURCE_KEY_NAME(a->rrs[i]->key))) {
*ret = a->rrs[i];
return 1;
}
}
return 0;
}
DnsAnswer *dns_answer_merge(DnsAnswer *a, DnsAnswer *b) {
_cleanup_(dns_answer_unrefp) DnsAnswer *ret = NULL;
DnsAnswer *k;
unsigned i;
int r;
if (a && (!b || b->n_rrs <= 0))
return dns_answer_ref(a);
if ((!a || a->n_rrs <= 0) && b)
return dns_answer_ref(b);
ret = dns_answer_new((a ? a->n_rrs : 0) + (b ? b->n_rrs : 0));
if (!ret)
return NULL;
if (a) {
for (i = 0; i < a->n_rrs; i++) {
r = dns_answer_add(ret, a->rrs[i]);
if (r < 0)
return NULL;
}
}
if (b) {
for (i = 0; i < b->n_rrs; i++) {
r = dns_answer_add(ret, b->rrs[i]);
if (r < 0)
return NULL;
}
}
k = ret;
ret = NULL;
return k;
}
void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local) {
DnsResourceRecord **rrs;
unsigned i, start, end;
assert(a);
if (a->n_rrs <= 1)
return;
start = 0;
end = a->n_rrs-1;
/* RFC 4795, Section 2.6 suggests we should order entries
* depending on whether the sender is a link-local address. */
rrs = newa(DnsResourceRecord*, a->n_rrs);
for (i = 0; i < a->n_rrs; i++) {
if (a->rrs[i]->key->class == DNS_CLASS_IN &&
((a->rrs[i]->key->type == DNS_TYPE_A && in_addr_is_link_local(AF_INET, (union in_addr_union*) &a->rrs[i]->a.in_addr) != prefer_link_local) ||
(a->rrs[i]->key->type == DNS_TYPE_AAAA && in_addr_is_link_local(AF_INET6, (union in_addr_union*) &a->rrs[i]->aaaa.in6_addr) != prefer_link_local)))
/* Order address records that are are not preferred to the end of the array */
rrs[end--] = a->rrs[i];
else
/* Order all other records to the beginning of the array */
rrs[start++] = a->rrs[i];
}
assert(start == end+1);
memcpy(a->rrs, rrs, sizeof(DnsResourceRecord*) * a->n_rrs);
}
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