1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2014 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 #include "resolved-dns-answer.h"
23 #include "resolved-dns-domain.h"
25 DnsAnswer *dns_answer_new(unsigned n) {
30 a = malloc0(offsetof(DnsAnswer, rrs) + sizeof(DnsResourceRecord*) * n);
40 DnsAnswer *dns_answer_ref(DnsAnswer *a) {
49 DnsAnswer *dns_answer_unref(DnsAnswer *a) {
58 for (i = 0; i < a->n_rrs; i++)
59 dns_resource_record_unref(a->rrs[i]);
68 int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr) {
75 for (i = 0; i < a->n_rrs; i++) {
76 r = dns_resource_record_equal(a->rrs[i], rr);
80 /* Entry already exists, keep the entry with
81 * the higher RR, or the one with TTL 0 */
83 if (rr->ttl == 0 || (rr->ttl > a->rrs[i]->ttl && a->rrs[i]->ttl != 0)) {
84 dns_resource_record_ref(rr);
85 dns_resource_record_unref(a->rrs[i]);
93 if (a->n_rrs >= a->n_allocated)
96 a->rrs[a->n_rrs++] = dns_resource_record_ref(rr);
100 int dns_answer_add_soa(DnsAnswer *a, const char *name, uint32_t ttl) {
101 _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *soa = NULL;
103 soa = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_SOA, name);
109 soa->soa.mname = strdup(name);
113 soa->soa.rname = strappend("root.", name);
118 soa->soa.refresh = 1;
121 soa->soa.minimum = ttl;
123 return dns_answer_add(a, soa);
126 int dns_answer_contains(DnsAnswer *a, DnsResourceKey *key) {
133 for (i = 0; i < a->n_rrs; i++) {
134 r = dns_resource_key_match_rr(key, a->rrs[i]);
144 int dns_answer_find_soa(DnsAnswer *a, DnsResourceKey *key, DnsResourceRecord **ret) {
151 /* For a SOA record we can never find a matching SOA record */
152 if (key->type == DNS_TYPE_SOA)
155 for (i = 0; i < a->n_rrs; i++) {
157 if (a->rrs[i]->key->class != DNS_CLASS_IN)
160 if (a->rrs[i]->key->type != DNS_TYPE_SOA)
163 if (dns_name_endswith(DNS_RESOURCE_KEY_NAME(key), DNS_RESOURCE_KEY_NAME(a->rrs[i]->key))) {
172 DnsAnswer *dns_answer_merge(DnsAnswer *a, DnsAnswer *b) {
173 _cleanup_(dns_answer_unrefp) DnsAnswer *ret = NULL;
178 if (a && (!b || b->n_rrs <= 0))
179 return dns_answer_ref(a);
180 if ((!a || a->n_rrs <= 0) && b)
181 return dns_answer_ref(b);
183 ret = dns_answer_new((a ? a->n_rrs : 0) + (b ? b->n_rrs : 0));
188 for (i = 0; i < a->n_rrs; i++) {
189 r = dns_answer_add(ret, a->rrs[i]);
196 for (i = 0; i < b->n_rrs; i++) {
197 r = dns_answer_add(ret, b->rrs[i]);
209 void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local) {
210 DnsResourceRecord **rrs;
211 unsigned i, start, end;
220 /* RFC 4795, Section 2.6 suggests we should order entries
221 * depending on whether the sender is a link-local address. */
223 rrs = newa(DnsResourceRecord*, a->n_rrs);
224 for (i = 0; i < a->n_rrs; i++) {
226 if (a->rrs[i]->key->class == DNS_CLASS_IN &&
227 ((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) ||
228 (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)))
229 /* Order address records that are are not preferred to the end of the array */
230 rrs[end--] = a->rrs[i];
232 /* Order all other records to the beginning of the array */
233 rrs[start++] = a->rrs[i];
236 assert(start == end+1);
237 memcpy(a->rrs, rrs, sizeof(DnsResourceRecord*) * a->n_rrs);