2014-07-22 21:48:41 +02:00
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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2014 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include "resolved-dns-answer.h"
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2014-07-23 00:57:25 +02:00
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#include "resolved-dns-domain.h"
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2014-07-22 21:48:41 +02:00
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DnsAnswer *dns_answer_new(unsigned n) {
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DnsAnswer *a;
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assert(n > 0);
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a = malloc0(offsetof(DnsAnswer, rrs) + sizeof(DnsResourceRecord*) * n);
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if (!a)
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return NULL;
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a->n_ref = 1;
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a->n_allocated = n;
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return a;
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}
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DnsAnswer *dns_answer_ref(DnsAnswer *a) {
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if (!a)
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return NULL;
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assert(a->n_ref > 0);
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a->n_ref++;
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return a;
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}
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DnsAnswer *dns_answer_unref(DnsAnswer *a) {
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if (!a)
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return NULL;
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assert(a->n_ref > 0);
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if (a->n_ref == 1) {
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unsigned i;
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for (i = 0; i < a->n_rrs; i++)
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dns_resource_record_unref(a->rrs[i]);
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free(a);
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} else
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a->n_ref--;
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return NULL;
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}
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int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr) {
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2014-07-23 00:57:25 +02:00
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unsigned i;
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int r;
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2014-07-22 21:48:41 +02:00
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assert(a);
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assert(rr);
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2014-07-23 00:57:25 +02:00
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for (i = 0; i < a->n_rrs; i++) {
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r = dns_resource_record_equal(a->rrs[i], rr);
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if (r < 0)
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return r;
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if (r > 0) {
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/* Entry already exists, keep the entry with
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* the higher RR, or the one with TTL 0 */
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if (rr->ttl == 0 || (rr->ttl > a->rrs[i]->ttl && a->rrs[i]->ttl != 0)) {
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dns_resource_record_ref(rr);
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dns_resource_record_unref(a->rrs[i]);
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a->rrs[i] = rr;
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}
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return 0;
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}
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}
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2014-07-22 21:48:41 +02:00
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if (a->n_rrs >= a->n_allocated)
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return -ENOSPC;
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a->rrs[a->n_rrs++] = dns_resource_record_ref(rr);
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2014-07-23 00:57:25 +02:00
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return 1;
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}
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int dns_answer_contains(DnsAnswer *a, DnsResourceKey *key) {
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unsigned i;
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int r;
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assert(a);
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assert(key);
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for (i = 0; i < a->n_rrs; i++) {
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r = dns_resource_key_match_rr(key, a->rrs[i]);
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if (r < 0)
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return r;
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if (r > 0)
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return 1;
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}
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return 0;
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}
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int dns_answer_find_soa(DnsAnswer *a, DnsResourceKey *key, DnsResourceRecord **ret) {
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unsigned i;
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assert(a);
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assert(key);
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assert(ret);
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for (i = 0; i < a->n_rrs; i++) {
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if (a->rrs[i]->key->class != DNS_CLASS_IN)
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continue;
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if (a->rrs[i]->key->type != DNS_TYPE_SOA)
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continue;
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if (dns_name_endswith(DNS_RESOURCE_KEY_NAME(key), DNS_RESOURCE_KEY_NAME(a->rrs[i]->key))) {
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*ret = a->rrs[i];
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return 1;
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}
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}
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2014-07-22 21:48:41 +02:00
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return 0;
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}
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2014-07-23 01:59:36 +02:00
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DnsAnswer *dns_answer_merge(DnsAnswer *a, DnsAnswer *b) {
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_cleanup_(dns_answer_unrefp) DnsAnswer *ret = NULL;
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DnsAnswer *k;
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unsigned i;
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int r;
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if (a && (!b || b->n_rrs <= 0))
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return dns_answer_ref(a);
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if ((!a || a->n_rrs <= 0) && b)
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return dns_answer_ref(b);
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ret = dns_answer_new((a ? a->n_rrs : 0) + (b ? b->n_rrs : 0));
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if (!ret)
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return NULL;
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if (a) {
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for (i = 0; i < a->n_rrs; i++) {
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r = dns_answer_add(ret, a->rrs[i]);
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if (r < 0)
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return NULL;
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}
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}
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if (b) {
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for (i = 0; i < b->n_rrs; i++) {
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r = dns_answer_add(ret, b->rrs[i]);
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if (r < 0)
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return NULL;
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}
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}
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k = ret;
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ret = NULL;
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return k;
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}
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2014-07-30 00:48:59 +02:00
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void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local) {
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DnsResourceRecord **rrs;
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unsigned i, start, end;
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assert(a);
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if (a->n_rrs <= 1)
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return;
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start = 0;
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end = a->n_rrs-1;
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/* RFC 4795, Section 2.6 suggests we should order entries
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* depending on whether the sender is a link-local address. */
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rrs = newa(DnsResourceRecord*, a->n_rrs);
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for (i = 0; i < a->n_rrs; i++) {
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if (a->rrs[i]->key->class == DNS_CLASS_IN &&
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((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) ||
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(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)))
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/* Order address records that are are not preferred to the end of the array */
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rrs[end--] = a->rrs[i];
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else
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/* Order all other records to the beginning of the array */
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rrs[start++] = a->rrs[i];
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}
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assert(start == end+1);
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memcpy(a->rrs, rrs, sizeof(DnsResourceRecord*) * a->n_rrs);
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}
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