resolved-dns-question.c revision 36d9205d669bcdcb04fa730d1f3549a9fc9a9001
/*-*- 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-question.h"
#include "dns-domain.h"
DnsQuestion *dns_question_new(unsigned n) {
DnsQuestion *q;
assert(n > 0);
q = malloc0(offsetof(DnsQuestion, keys) + sizeof(DnsResourceKey*) * n);
if (!q)
return NULL;
q->n_ref = 1;
q->n_allocated = n;
return q;
}
DnsQuestion *dns_question_ref(DnsQuestion *q) {
if (!q)
return NULL;
assert(q->n_ref > 0);
q->n_ref++;
return q;
}
DnsQuestion *dns_question_unref(DnsQuestion *q) {
if (!q)
return NULL;
assert(q->n_ref > 0);
if (q->n_ref == 1) {
unsigned i;
for (i = 0; i < q->n_keys; i++)
dns_resource_key_unref(q->keys[i]);
free(q);
} else
q->n_ref--;
return NULL;
}
int dns_question_add(DnsQuestion *q, DnsResourceKey *key) {
unsigned i;
int r;
assert(key);
if (!q)
return -ENOSPC;
for (i = 0; i < q->n_keys; i++) {
r = dns_resource_key_equal(q->keys[i], key);
if (r < 0)
return r;
if (r > 0)
return 0;
}
if (q->n_keys >= q->n_allocated)
return -ENOSPC;
q->keys[q->n_keys++] = dns_resource_key_ref(key);
return 0;
}
int dns_question_matches_rr(DnsQuestion *q, DnsResourceRecord *rr) {
unsigned i;
int r;
assert(rr);
if (!q)
return 0;
for (i = 0; i < q->n_keys; i++) {
r = dns_resource_key_match_rr(q->keys[i], rr);
if (r != 0)
return r;
}
return 0;
}
int dns_question_matches_cname(DnsQuestion *q, DnsResourceRecord *rr) {
unsigned i;
int r;
assert(rr);
if (!q)
return 0;
for (i = 0; i < q->n_keys; i++) {
r = dns_resource_key_match_cname(q->keys[i], rr);
if (r != 0)
return r;
}
return 0;
}
int dns_question_is_valid(DnsQuestion *q) {
const char *name;
unsigned i;
int r;
if (!q)
return 0;
if (q->n_keys <= 0)
return 0;
if (q->n_keys > 65535)
return 0;
name = DNS_RESOURCE_KEY_NAME(q->keys[0]);
if (!name)
return 0;
/* Check that all keys in this question bear the same name */
for (i = 1; i < q->n_keys; i++) {
assert(q->keys[i]);
r = dns_name_equal(DNS_RESOURCE_KEY_NAME(q->keys[i]), name);
if (r <= 0)
return r;
}
return 1;
}
int dns_question_is_superset(DnsQuestion *q, DnsQuestion *other) {
unsigned j;
int r;
/* Checks if all keys in "other" are also contained in "q" */
if (!other)
return 1;
for (j = 0; j < other->n_keys; j++) {
DnsResourceKey *b = other->keys[j];
bool found = false;
unsigned i;
if (!q)
return 0;
for (i = 0; i < q->n_keys; i++) {
DnsResourceKey *a = q->keys[i];
r = dns_name_equal(DNS_RESOURCE_KEY_NAME(a), DNS_RESOURCE_KEY_NAME(b));
if (r < 0)
return r;
if (r == 0)
continue;
if (a->class != b->class && a->class != DNS_CLASS_ANY)
continue;
if (a->type != b->type && a->type != DNS_TYPE_ANY)
continue;
found = true;
break;
}
if (!found)
return 0;
}
return 1;
}
int dns_question_contains(DnsQuestion *a, DnsResourceKey *k) {
unsigned j;
int r;
assert(k);
if (!a)
return 0;
for (j = 0; j < a->n_keys; j++) {
r = dns_resource_key_equal(a->keys[j], k);
if (r != 0)
return r;
}
return 0;
}
int dns_question_is_equal(DnsQuestion *a, DnsQuestion *b) {
unsigned j;
int r;
if (!a)
return !b || b->n_keys == 0;
if (!b)
return a->n_keys == 0;
/* Checks if all keys in a are also contained b, and vice versa */
for (j = 0; j < a->n_keys; j++) {
r = dns_question_contains(b, a->keys[j]);
if (r <= 0)
return r;
}
for (j = 0; j < b->n_keys; j++) {
r = dns_question_contains(a, b->keys[j]);
if (r <= 0)
return r;
}
return 1;
}
int dns_question_cname_redirect(DnsQuestion *q, const DnsResourceRecord *cname, DnsQuestion **ret) {
_cleanup_(dns_question_unrefp) DnsQuestion *n = NULL;
bool same = true;
unsigned i;
int r;
assert(cname);
assert(ret);
if (!q) {
n = dns_question_new(0);
if (!n)
return -ENOMEM;
*ret = n;
n = 0;
return 0;
}
for (i = 0; i < q->n_keys; i++) {
r = dns_name_equal(DNS_RESOURCE_KEY_NAME(q->keys[i]), cname->cname.name);
if (r < 0)
return r;
if (r == 0) {
same = false;
break;
}
}
if (same) {
/* Shortcut, the names are already right */
*ret = dns_question_ref(q);
return 0;
}
n = dns_question_new(q->n_keys);
if (!n)
return -ENOMEM;
/* Create a new question, and patch in the new name */
for (i = 0; i < q->n_keys; i++) {
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *k = NULL;
k = dns_resource_key_new_redirect(q->keys[i], cname);
if (!k)
return -ENOMEM;
r = dns_question_add(n, k);
if (r < 0)
return r;
}
*ret = n;
n = NULL;
return 1;
}