859 lines
24 KiB
C
859 lines
24 KiB
C
/***
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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 "alloc-util.h"
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#include "dns-domain.h"
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#include "resolved-dns-answer.h"
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#include "resolved-dns-dnssec.h"
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#include "string-util.h"
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DnsAnswer *dns_answer_new(unsigned n) {
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DnsAnswer *a;
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a = malloc0(offsetof(DnsAnswer, items) + sizeof(DnsAnswerItem) * 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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static void dns_answer_flush(DnsAnswer *a) {
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DnsResourceRecord *rr;
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if (!a)
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return;
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DNS_ANSWER_FOREACH(rr, a)
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dns_resource_record_unref(rr);
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a->n_rrs = 0;
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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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dns_answer_flush(a);
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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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static int dns_answer_add_raw(DnsAnswer *a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags) {
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assert(rr);
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if (!a)
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return -ENOSPC;
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if (a->n_rrs >= a->n_allocated)
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return -ENOSPC;
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a->items[a->n_rrs++] = (DnsAnswerItem) {
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.rr = dns_resource_record_ref(rr),
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.ifindex = ifindex,
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.flags = flags,
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};
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return 1;
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}
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static int dns_answer_add_raw_all(DnsAnswer *a, DnsAnswer *source) {
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DnsResourceRecord *rr;
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DnsAnswerFlags flags;
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int ifindex, r;
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DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, source) {
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r = dns_answer_add_raw(a, rr, ifindex, flags);
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if (r < 0)
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return r;
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}
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return 0;
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}
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int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags) {
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unsigned i;
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int r;
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assert(rr);
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if (!a)
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return -ENOSPC;
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if (a->n_ref > 1)
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return -EBUSY;
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for (i = 0; i < a->n_rrs; i++) {
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if (a->items[i].ifindex != ifindex)
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continue;
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r = dns_resource_record_equal(a->items[i].rr, 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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/* Don't mix contradicting TTLs (see below) */
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if ((rr->ttl == 0) != (a->items[i].rr->ttl == 0))
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return -EINVAL;
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/* Entry already exists, keep the entry with
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* the higher RR. */
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if (rr->ttl > a->items[i].rr->ttl) {
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dns_resource_record_ref(rr);
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dns_resource_record_unref(a->items[i].rr);
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a->items[i].rr = rr;
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}
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a->items[i].flags |= flags;
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return 0;
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}
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r = dns_resource_key_equal(a->items[i].rr->key, rr->key);
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if (r < 0)
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return r;
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if (r > 0) {
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/* There's already an RR of the same RRset in
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* place! Let's see if the TTLs more or less
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* match. We don't really care if they match
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* precisely, but we do care whether one is 0
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* and the other is not. See RFC 2181, Section
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* 5.2. */
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if ((rr->ttl == 0) != (a->items[i].rr->ttl == 0))
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return -EINVAL;
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}
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}
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return dns_answer_add_raw(a, rr, ifindex, flags);
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}
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static int dns_answer_add_all(DnsAnswer *a, DnsAnswer *b) {
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DnsResourceRecord *rr;
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DnsAnswerFlags flags;
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int ifindex, r;
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DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, b) {
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r = dns_answer_add(a, rr, ifindex, flags);
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if (r < 0)
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return r;
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}
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return 0;
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}
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int dns_answer_add_extend(DnsAnswer **a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags) {
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int r;
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assert(a);
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assert(rr);
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r = dns_answer_reserve_or_clone(a, 1);
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if (r < 0)
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return r;
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return dns_answer_add(*a, rr, ifindex, flags);
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}
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int dns_answer_add_soa(DnsAnswer *a, const char *name, uint32_t ttl, int ifindex) {
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_cleanup_(dns_resource_record_unrefp) DnsResourceRecord *soa = NULL;
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soa = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_SOA, name);
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if (!soa)
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return -ENOMEM;
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soa->ttl = ttl;
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soa->soa.mname = strdup(name);
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if (!soa->soa.mname)
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return -ENOMEM;
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soa->soa.rname = strappend("root.", name);
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if (!soa->soa.rname)
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return -ENOMEM;
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soa->soa.serial = 1;
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soa->soa.refresh = 1;
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soa->soa.retry = 1;
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soa->soa.expire = 1;
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soa->soa.minimum = ttl;
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return dns_answer_add(a, soa, ifindex, DNS_ANSWER_AUTHENTICATED);
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}
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int dns_answer_match_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *ret_flags) {
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DnsAnswerFlags flags = 0, i_flags;
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DnsResourceRecord *i;
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bool found = false;
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int r;
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assert(key);
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DNS_ANSWER_FOREACH_FLAGS(i, i_flags, a) {
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r = dns_resource_key_match_rr(key, i, NULL);
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if (r < 0)
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return r;
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if (r == 0)
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continue;
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if (!ret_flags)
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return 1;
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if (found)
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flags &= i_flags;
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else {
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flags = i_flags;
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found = true;
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}
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}
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if (ret_flags)
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*ret_flags = flags;
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return found;
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}
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int dns_answer_contains_rr(DnsAnswer *a, DnsResourceRecord *rr, DnsAnswerFlags *ret_flags) {
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DnsAnswerFlags flags = 0, i_flags;
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DnsResourceRecord *i;
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bool found = false;
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int r;
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assert(rr);
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DNS_ANSWER_FOREACH_FLAGS(i, i_flags, a) {
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r = dns_resource_record_equal(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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continue;
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if (!ret_flags)
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return 1;
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if (found)
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flags &= i_flags;
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else {
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flags = i_flags;
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found = true;
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}
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}
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if (ret_flags)
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*ret_flags = flags;
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return found;
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}
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int dns_answer_contains_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *ret_flags) {
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DnsAnswerFlags flags = 0, i_flags;
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DnsResourceRecord *i;
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bool found = false;
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int r;
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assert(key);
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DNS_ANSWER_FOREACH_FLAGS(i, i_flags, a) {
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r = dns_resource_key_equal(i->key, key);
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if (r < 0)
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return r;
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if (r == 0)
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continue;
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if (!ret_flags)
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return true;
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if (found)
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flags &= i_flags;
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else {
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flags = i_flags;
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found = true;
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}
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}
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if (ret_flags)
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*ret_flags = flags;
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return found;
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}
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int dns_answer_contains_nsec_or_nsec3(DnsAnswer *a) {
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DnsResourceRecord *i;
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DNS_ANSWER_FOREACH(i, a) {
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if (IN_SET(i->key->type, DNS_TYPE_NSEC, DNS_TYPE_NSEC3))
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return true;
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}
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return false;
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}
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int dns_answer_contains_zone_nsec3(DnsAnswer *answer, const char *zone) {
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DnsResourceRecord *rr;
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int r;
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/* Checks whether the specified answer contains at least one NSEC3 RR in the specified zone */
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DNS_ANSWER_FOREACH(rr, answer) {
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const char *p;
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if (rr->key->type != DNS_TYPE_NSEC3)
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continue;
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p = dns_resource_key_name(rr->key);
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r = dns_name_parent(&p);
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if (r < 0)
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return r;
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if (r == 0)
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continue;
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r = dns_name_equal(p, zone);
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if (r != 0)
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return r;
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}
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return false;
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}
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int dns_answer_find_soa(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags) {
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DnsResourceRecord *rr, *soa = NULL;
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DnsAnswerFlags rr_flags, soa_flags = 0;
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int r;
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assert(key);
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/* For a SOA record we can never find a matching SOA record */
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if (key->type == DNS_TYPE_SOA)
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return 0;
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DNS_ANSWER_FOREACH_FLAGS(rr, rr_flags, a) {
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r = dns_resource_key_match_soa(key, rr->key);
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if (r < 0)
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return r;
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if (r > 0) {
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if (soa) {
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r = dns_name_endswith(dns_resource_key_name(rr->key), dns_resource_key_name(soa->key));
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if (r < 0)
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return r;
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if (r > 0)
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continue;
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}
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soa = rr;
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soa_flags = rr_flags;
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}
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}
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if (!soa)
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return 0;
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if (ret)
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*ret = soa;
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if (flags)
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*flags = soa_flags;
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return 1;
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}
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int dns_answer_find_cname_or_dname(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags) {
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DnsResourceRecord *rr;
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DnsAnswerFlags rr_flags;
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int r;
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assert(key);
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/* For a {C,D}NAME record we can never find a matching {C,D}NAME record */
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if (!dns_type_may_redirect(key->type))
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return 0;
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DNS_ANSWER_FOREACH_FLAGS(rr, rr_flags, a) {
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r = dns_resource_key_match_cname_or_dname(key, rr->key, NULL);
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if (r < 0)
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return r;
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if (r > 0) {
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if (ret)
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*ret = rr;
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if (flags)
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*flags = rr_flags;
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return 1;
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}
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}
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return 0;
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}
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int dns_answer_merge(DnsAnswer *a, DnsAnswer *b, DnsAnswer **ret) {
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_cleanup_(dns_answer_unrefp) DnsAnswer *k = NULL;
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int r;
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assert(ret);
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if (dns_answer_size(a) <= 0) {
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*ret = dns_answer_ref(b);
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return 0;
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}
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if (dns_answer_size(b) <= 0) {
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*ret = dns_answer_ref(a);
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return 0;
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}
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k = dns_answer_new(a->n_rrs + b->n_rrs);
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if (!k)
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return -ENOMEM;
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r = dns_answer_add_raw_all(k, a);
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if (r < 0)
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return r;
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r = dns_answer_add_all(k, b);
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if (r < 0)
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return r;
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*ret = k;
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k = NULL;
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return 0;
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}
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int dns_answer_extend(DnsAnswer **a, DnsAnswer *b) {
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DnsAnswer *merged;
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int r;
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assert(a);
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r = dns_answer_merge(*a, b, &merged);
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if (r < 0)
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return r;
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dns_answer_unref(*a);
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*a = merged;
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return 0;
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}
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int dns_answer_remove_by_key(DnsAnswer **a, const DnsResourceKey *key) {
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bool found = false, other = false;
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DnsResourceRecord *rr;
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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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/* Remove all entries matching the specified key from *a */
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DNS_ANSWER_FOREACH(rr, *a) {
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r = dns_resource_key_equal(rr->key, key);
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if (r < 0)
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return r;
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if (r > 0)
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found = true;
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else
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other = true;
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if (found && other)
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break;
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}
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if (!found)
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return 0;
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if (!other) {
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*a = dns_answer_unref(*a); /* Return NULL for the empty answer */
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return 1;
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}
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if ((*a)->n_ref > 1) {
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_cleanup_(dns_answer_unrefp) DnsAnswer *copy = NULL;
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DnsAnswerFlags flags;
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int ifindex;
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copy = dns_answer_new((*a)->n_rrs);
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if (!copy)
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return -ENOMEM;
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DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, *a) {
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r = dns_resource_key_equal(rr->key, key);
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if (r < 0)
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return r;
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if (r > 0)
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continue;
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r = dns_answer_add_raw(copy, rr, ifindex, flags);
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if (r < 0)
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return r;
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}
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dns_answer_unref(*a);
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*a = copy;
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copy = NULL;
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return 1;
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}
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/* Only a single reference, edit in-place */
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i = 0;
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for (;;) {
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if (i >= (*a)->n_rrs)
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break;
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r = dns_resource_key_equal((*a)->items[i].rr->key, key);
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if (r < 0)
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return r;
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if (r > 0) {
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/* Kill this entry */
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dns_resource_record_unref((*a)->items[i].rr);
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memmove((*a)->items + i, (*a)->items + i + 1, sizeof(DnsAnswerItem) * ((*a)->n_rrs - i - 1));
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(*a)->n_rrs--;
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continue;
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} else
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/* Keep this entry */
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i++;
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}
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return 1;
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}
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int dns_answer_remove_by_rr(DnsAnswer **a, DnsResourceRecord *rm) {
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bool found = false, other = false;
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DnsResourceRecord *rr;
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unsigned i;
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int r;
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assert(a);
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assert(rm);
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/* Remove all entries matching the specified RR from *a */
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DNS_ANSWER_FOREACH(rr, *a) {
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r = dns_resource_record_equal(rr, rm);
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if (r < 0)
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return r;
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if (r > 0)
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found = true;
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else
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other = true;
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if (found && other)
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break;
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}
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if (!found)
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return 0;
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if (!other) {
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*a = dns_answer_unref(*a); /* Return NULL for the empty answer */
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return 1;
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}
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|
|
if ((*a)->n_ref > 1) {
|
|
_cleanup_(dns_answer_unrefp) DnsAnswer *copy = NULL;
|
|
DnsAnswerFlags flags;
|
|
int ifindex;
|
|
|
|
copy = dns_answer_new((*a)->n_rrs);
|
|
if (!copy)
|
|
return -ENOMEM;
|
|
|
|
DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, *a) {
|
|
r = dns_resource_record_equal(rr, rm);
|
|
if (r < 0)
|
|
return r;
|
|
if (r > 0)
|
|
continue;
|
|
|
|
r = dns_answer_add_raw(copy, rr, ifindex, flags);
|
|
if (r < 0)
|
|
return r;
|
|
}
|
|
|
|
dns_answer_unref(*a);
|
|
*a = copy;
|
|
copy = NULL;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/* Only a single reference, edit in-place */
|
|
|
|
i = 0;
|
|
for (;;) {
|
|
if (i >= (*a)->n_rrs)
|
|
break;
|
|
|
|
r = dns_resource_record_equal((*a)->items[i].rr, rm);
|
|
if (r < 0)
|
|
return r;
|
|
if (r > 0) {
|
|
/* Kill this entry */
|
|
|
|
dns_resource_record_unref((*a)->items[i].rr);
|
|
memmove((*a)->items + i, (*a)->items + i + 1, sizeof(DnsAnswerItem) * ((*a)->n_rrs - i - 1));
|
|
(*a)->n_rrs--;
|
|
continue;
|
|
|
|
} else
|
|
/* Keep this entry */
|
|
i++;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
int dns_answer_copy_by_key(DnsAnswer **a, DnsAnswer *source, const DnsResourceKey *key, DnsAnswerFlags or_flags) {
|
|
DnsResourceRecord *rr_source;
|
|
int ifindex_source, r;
|
|
DnsAnswerFlags flags_source;
|
|
|
|
assert(a);
|
|
assert(key);
|
|
|
|
/* Copy all RRs matching the specified key from source into *a */
|
|
|
|
DNS_ANSWER_FOREACH_FULL(rr_source, ifindex_source, flags_source, source) {
|
|
|
|
r = dns_resource_key_equal(rr_source->key, key);
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
continue;
|
|
|
|
/* Make space for at least one entry */
|
|
r = dns_answer_reserve_or_clone(a, 1);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
r = dns_answer_add(*a, rr_source, ifindex_source, flags_source|or_flags);
|
|
if (r < 0)
|
|
return r;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int dns_answer_move_by_key(DnsAnswer **to, DnsAnswer **from, const DnsResourceKey *key, DnsAnswerFlags or_flags) {
|
|
int r;
|
|
|
|
assert(to);
|
|
assert(from);
|
|
assert(key);
|
|
|
|
r = dns_answer_copy_by_key(to, *from, key, or_flags);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
return dns_answer_remove_by_key(from, key);
|
|
}
|
|
|
|
void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local) {
|
|
DnsAnswerItem *items;
|
|
unsigned i, start, end;
|
|
|
|
if (!a)
|
|
return;
|
|
|
|
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. */
|
|
|
|
items = newa(DnsAnswerItem, a->n_rrs);
|
|
for (i = 0; i < a->n_rrs; i++) {
|
|
|
|
if (a->items[i].rr->key->class == DNS_CLASS_IN &&
|
|
((a->items[i].rr->key->type == DNS_TYPE_A && in_addr_is_link_local(AF_INET, (union in_addr_union*) &a->items[i].rr->a.in_addr) != prefer_link_local) ||
|
|
(a->items[i].rr->key->type == DNS_TYPE_AAAA && in_addr_is_link_local(AF_INET6, (union in_addr_union*) &a->items[i].rr->aaaa.in6_addr) != prefer_link_local)))
|
|
/* Order address records that are not preferred to the end of the array */
|
|
items[end--] = a->items[i];
|
|
else
|
|
/* Order all other records to the beginning of the array */
|
|
items[start++] = a->items[i];
|
|
}
|
|
|
|
assert(start == end+1);
|
|
memcpy(a->items, items, sizeof(DnsAnswerItem) * a->n_rrs);
|
|
}
|
|
|
|
int dns_answer_reserve(DnsAnswer **a, unsigned n_free) {
|
|
DnsAnswer *n;
|
|
|
|
assert(a);
|
|
|
|
if (n_free <= 0)
|
|
return 0;
|
|
|
|
if (*a) {
|
|
unsigned ns;
|
|
|
|
if ((*a)->n_ref > 1)
|
|
return -EBUSY;
|
|
|
|
ns = (*a)->n_rrs + n_free;
|
|
|
|
if ((*a)->n_allocated >= ns)
|
|
return 0;
|
|
|
|
/* Allocate more than we need */
|
|
ns *= 2;
|
|
|
|
n = realloc(*a, offsetof(DnsAnswer, items) + sizeof(DnsAnswerItem) * ns);
|
|
if (!n)
|
|
return -ENOMEM;
|
|
|
|
n->n_allocated = ns;
|
|
} else {
|
|
n = dns_answer_new(n_free);
|
|
if (!n)
|
|
return -ENOMEM;
|
|
}
|
|
|
|
*a = n;
|
|
return 0;
|
|
}
|
|
|
|
int dns_answer_reserve_or_clone(DnsAnswer **a, unsigned n_free) {
|
|
_cleanup_(dns_answer_unrefp) DnsAnswer *n = NULL;
|
|
int r;
|
|
|
|
assert(a);
|
|
|
|
/* Tries to extend the DnsAnswer object. And if that's not
|
|
* possible, since we are not the sole owner, then allocate a
|
|
* new, appropriately sized one. Either way, after this call
|
|
* the object will only have a single reference, and has room
|
|
* for at least the specified number of RRs. */
|
|
|
|
r = dns_answer_reserve(a, n_free);
|
|
if (r != -EBUSY)
|
|
return r;
|
|
|
|
assert(*a);
|
|
|
|
n = dns_answer_new(((*a)->n_rrs + n_free) * 2);
|
|
if (!n)
|
|
return -ENOMEM;
|
|
|
|
r = dns_answer_add_raw_all(n, *a);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
dns_answer_unref(*a);
|
|
*a = n;
|
|
n = NULL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
void dns_answer_dump(DnsAnswer *answer, FILE *f) {
|
|
DnsResourceRecord *rr;
|
|
DnsAnswerFlags flags;
|
|
int ifindex;
|
|
|
|
if (!f)
|
|
f = stdout;
|
|
|
|
DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, answer) {
|
|
const char *t;
|
|
|
|
fputc('\t', f);
|
|
|
|
t = dns_resource_record_to_string(rr);
|
|
if (!t) {
|
|
log_oom();
|
|
continue;
|
|
}
|
|
|
|
fputs(t, f);
|
|
|
|
if (ifindex != 0 || flags & (DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE|DNS_ANSWER_SHARED_OWNER))
|
|
fputs("\t;", f);
|
|
|
|
if (ifindex != 0)
|
|
printf(" ifindex=%i", ifindex);
|
|
if (flags & DNS_ANSWER_AUTHENTICATED)
|
|
fputs(" authenticated", f);
|
|
if (flags & DNS_ANSWER_CACHEABLE)
|
|
fputs(" cachable", f);
|
|
if (flags & DNS_ANSWER_SHARED_OWNER)
|
|
fputs(" shared-owner", f);
|
|
|
|
fputc('\n', f);
|
|
}
|
|
}
|
|
|
|
bool dns_answer_has_dname_for_cname(DnsAnswer *a, DnsResourceRecord *cname) {
|
|
DnsResourceRecord *rr;
|
|
int r;
|
|
|
|
assert(cname);
|
|
|
|
/* Checks whether the answer contains a DNAME record that indicates that the specified CNAME record is
|
|
* synthesized from it */
|
|
|
|
if (cname->key->type != DNS_TYPE_CNAME)
|
|
return 0;
|
|
|
|
DNS_ANSWER_FOREACH(rr, a) {
|
|
_cleanup_free_ char *n = NULL;
|
|
|
|
if (rr->key->type != DNS_TYPE_DNAME)
|
|
continue;
|
|
if (rr->key->class != cname->key->class)
|
|
continue;
|
|
|
|
r = dns_name_change_suffix(cname->cname.name, rr->dname.name, dns_resource_key_name(rr->key), &n);
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
continue;
|
|
|
|
r = dns_name_equal(n, dns_resource_key_name(cname->key));
|
|
if (r < 0)
|
|
return r;
|
|
if (r > 0)
|
|
return 1;
|
|
|
|
}
|
|
|
|
return 0;
|
|
}
|