resolved-dns-question.c revision 58db254ade4fb2ef77de68f28c4f13814819f6a1
/*-*- 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 "alloc-util.h"
#include "dns-domain.h"
#include "resolved-dns-question.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_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);
assert(IN_SET(cname->key->type, DNS_TYPE_CNAME, DNS_TYPE_DNAME));
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++) {
_cleanup_free_ char *destination = NULL;
const char *d;
if (cname->key->type == DNS_TYPE_CNAME)
d = cname->cname.name;
else {
r = dns_name_change_suffix(DNS_RESOURCE_KEY_NAME(q->keys[i]), DNS_RESOURCE_KEY_NAME(cname->key), cname->dname.name, &destination);
if (r < 0)
return r;
if (r == 0)
continue;
d = destination;
}
r = dns_name_equal(DNS_RESOURCE_KEY_NAME(q->keys[i]), d);
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;
}
const char *dns_question_name(DnsQuestion *q) {
assert(q);
if (q->n_keys < 1)
return NULL;
return DNS_RESOURCE_KEY_NAME(q->keys[0]);
}
int dns_question_new_address(DnsQuestion **ret, int family, const char *name) {
_cleanup_(dns_question_unrefp) DnsQuestion *q = NULL;
int r;
assert(ret);
assert(name);
if (!IN_SET(family, AF_INET, AF_INET6, AF_UNSPEC))
return -EAFNOSUPPORT;
q = dns_question_new(family == AF_UNSPEC ? 2 : 1);
if (!q)
return -ENOMEM;
if (family != AF_INET6) {
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_A, name);
if (!key)
return -ENOMEM;
r = dns_question_add(q, key);
if (r < 0)
return r;
}
if (family != AF_INET) {
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_AAAA, name);
if (!key)
return -ENOMEM;
r = dns_question_add(q, key);
if (r < 0)
return r;
}
*ret = q;
q = NULL;
return 0;
}
int dns_question_new_reverse(DnsQuestion **ret, int family, const union in_addr_union *a) {
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
_cleanup_(dns_question_unrefp) DnsQuestion *q = NULL;
_cleanup_free_ char *reverse = NULL;
int r;
assert(ret);
assert(a);
if (!IN_SET(family, AF_INET, AF_INET6, AF_UNSPEC))
return -EAFNOSUPPORT;
r = dns_name_reverse(family, a, &reverse);
if (r < 0)
return r;
q = dns_question_new(1);
if (!q)
return -ENOMEM;
key = dns_resource_key_new_consume(DNS_CLASS_IN, DNS_TYPE_PTR, reverse);
if (!key)
return -ENOMEM;
reverse = NULL;
r = dns_question_add(q, key);
if (r < 0)
return r;
*ret = q;
q = NULL;
return 0;
}
int dns_question_new_service(DnsQuestion **ret, const char *name, bool with_txt) {
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
_cleanup_(dns_question_unrefp) DnsQuestion *q = NULL;
int r;
assert(ret);
assert(name);
q = dns_question_new(1 + with_txt);
if (!q)
return -ENOMEM;
key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_SRV, name);
if (!key)
return -ENOMEM;
r = dns_question_add(q, key);
if (r < 0)
return r;
if (with_txt) {
dns_resource_key_unref(key);
key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_TXT, name);
if (!key)
return -ENOMEM;
r = dns_question_add(q, key);
if (r < 0)
return r;
}
*ret = q;
q = NULL;
return 0;
}