blob: aefdaa0eeb76f53147848fddb3f0aa61620ae775 [file] [log] [blame]
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "alloc-util.h"
#include "dns-domain.h"
#include "dns-type.h"
#include "resolved-dns-question.h"
DnsQuestion *dns_question_new(size_t n) {
DnsQuestion *q;
if (n > UINT16_MAX) /* We can only place 64K key in an question section at max */
n = UINT16_MAX;
q = malloc0(offsetof(DnsQuestion, items) + sizeof(DnsQuestionItem) * n);
if (!q)
return NULL;
q->n_ref = 1;
q->n_allocated = n;
return q;
}
static DnsQuestion *dns_question_free(DnsQuestion *q) {
DnsResourceKey *key;
assert(q);
DNS_QUESTION_FOREACH(key, q)
dns_resource_key_unref(key);
return mfree(q);
}
DEFINE_TRIVIAL_REF_UNREF_FUNC(DnsQuestion, dns_question, dns_question_free);
int dns_question_add_raw(DnsQuestion *q, DnsResourceKey *key, DnsQuestionFlags flags) {
/* Insert without checking for duplicates. */
assert(key);
assert(q);
if (q->n_keys >= q->n_allocated)
return -ENOSPC;
q->items[q->n_keys++] = (DnsQuestionItem) {
.key = dns_resource_key_ref(key),
.flags = flags,
};
return 0;
}
int dns_question_add(DnsQuestion *q, DnsResourceKey *key, DnsQuestionFlags flags) {
DnsQuestionItem *item;
int r;
assert(key);
if (!q)
return -ENOSPC;
DNS_QUESTION_FOREACH_ITEM(item, q) {
r = dns_resource_key_equal(item->key, key);
if (r < 0)
return r;
if (r > 0 && item->flags == flags)
return 0;
}
return dns_question_add_raw(q, key, flags);
}
int dns_question_matches_rr(DnsQuestion *q, DnsResourceRecord *rr, const char *search_domain) {
DnsResourceKey *key;
int r;
assert(rr);
if (!q)
return 0;
DNS_QUESTION_FOREACH(key, q) {
r = dns_resource_key_match_rr(key, rr, search_domain);
if (r != 0)
return r;
}
return 0;
}
int dns_question_matches_cname_or_dname(DnsQuestion *q, DnsResourceRecord *rr, const char *search_domain) {
DnsResourceKey *key;
int r;
assert(rr);
if (!q)
return 0;
if (!IN_SET(rr->key->type, DNS_TYPE_CNAME, DNS_TYPE_DNAME))
return 0;
DNS_QUESTION_FOREACH(key, q) {
/* For a {C,D}NAME record we can never find a matching {C,D}NAME record */
if (!dns_type_may_redirect(key->type))
return 0;
r = dns_resource_key_match_cname_or_dname(key, rr->key, search_domain);
if (r != 0)
return r;
}
return 0;
}
int dns_question_is_valid_for_query(DnsQuestion *q) {
const char *name;
size_t 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->items[0].key);
if (!name)
return 0;
/* Check that all keys in this question bear the same name */
for (i = 0; i < q->n_keys; i++) {
assert(q->items[i].key);
if (i > 0) {
r = dns_name_equal(dns_resource_key_name(q->items[i].key), name);
if (r <= 0)
return r;
}
if (!dns_type_is_valid_query(q->items[i].key->type))
return 0;
}
return 1;
}
int dns_question_contains_key(DnsQuestion *q, const DnsResourceKey *k) {
size_t j;
int r;
assert(k);
if (!q)
return 0;
for (j = 0; j < q->n_keys; j++) {
r = dns_resource_key_equal(q->items[j].key, k);
if (r != 0)
return r;
}
return 0;
}
static int dns_question_contains_item(DnsQuestion *q, const DnsQuestionItem *i) {
DnsQuestionItem *item;
int r;
assert(i);
DNS_QUESTION_FOREACH_ITEM(item, q) {
if (item->flags != i->flags)
continue;
r = dns_resource_key_equal(item->key, i->key);
if (r != 0)
return r;
}
return false;
}
int dns_question_is_equal(DnsQuestion *a, DnsQuestion *b) {
DnsQuestionItem *item;
int r;
if (a == b)
return 1;
if (!a)
return !b || b->n_keys == 0;
if (!b)
return a->n_keys == 0;
/* Checks if all items in a are also contained b, and vice versa */
DNS_QUESTION_FOREACH_ITEM(item, a) {
r = dns_question_contains_item(b, item);
if (r <= 0)
return r;
}
DNS_QUESTION_FOREACH_ITEM(item, b) {
r = dns_question_contains_item(a, item);
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;
DnsResourceKey *key;
bool same = true;
int r;
assert(cname);
assert(ret);
assert(IN_SET(cname->key->type, DNS_TYPE_CNAME, DNS_TYPE_DNAME));
if (dns_question_size(q) <= 0) {
*ret = NULL;
return 0;
}
DNS_QUESTION_FOREACH(key, q) {
_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(key), 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(key), d);
if (r < 0)
return r;
if (r == 0) {
same = false;
break;
}
}
/* Fully the same, indicate we didn't do a thing */
if (same) {
*ret = NULL;
return 0;
}
n = dns_question_new(q->n_keys);
if (!n)
return -ENOMEM;
/* Create a new question, and patch in the new name */
DNS_QUESTION_FOREACH(key, q) {
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *k = NULL;
k = dns_resource_key_new_redirect(key, cname);
if (!k)
return -ENOMEM;
r = dns_question_add(n, k, 0);
if (r < 0)
return r;
}
*ret = TAKE_PTR(n);
return 1;
}
const char *dns_question_first_name(DnsQuestion *q) {
if (!q)
return NULL;
if (q->n_keys < 1)
return NULL;
return dns_resource_key_name(q->items[0].key);
}
int dns_question_new_address(DnsQuestion **ret, int family, const char *name, bool convert_idna) {
_cleanup_(dns_question_unrefp) DnsQuestion *q = NULL;
_cleanup_free_ char *buf = NULL;
int r;
assert(ret);
assert(name);
if (!IN_SET(family, AF_INET, AF_INET6, AF_UNSPEC))
return -EAFNOSUPPORT;
if (convert_idna) {
r = dns_name_apply_idna(name, &buf);
if (r < 0)
return r;
if (r > 0 && !streq(name, buf))
name = buf;
else
/* We did not manage to create convert the idna name, or it's
* the same as the original name. We assume the caller already
* created an unconverted question, so let's not repeat work
* unnecessarily. */
return -EALREADY;
}
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, 0);
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, 0);
if (r < 0)
return r;
}
*ret = TAKE_PTR(q);
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, 0);
if (r < 0)
return r;
*ret = TAKE_PTR(q);
return 0;
}
int dns_question_new_service(
DnsQuestion **ret,
const char *service,
const char *type,
const char *domain,
bool with_txt,
bool convert_idna) {
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
_cleanup_(dns_question_unrefp) DnsQuestion *q = NULL;
_cleanup_free_ char *buf = NULL, *joined = NULL;
const char *name;
int r;
assert(ret);
/* We support three modes of invocation:
*
* 1. Only a domain is specified, in which case we assume a properly encoded SRV RR name, including service
* type and possibly a service name. If specified in this way we assume it's already IDNA converted if
* that's necessary.
*
* 2. Both service type and a domain specified, in which case a normal SRV RR is assumed, without a DNS-SD
* style prefix. In this case we'll IDNA convert the domain, if that's requested.
*
* 3. All three of service name, type and domain are specified, in which case a DNS-SD service is put
* together. The service name is never IDNA converted, and the domain is if requested.
*
* It's not supported to specify a service name without a type, or no domain name.
*/
if (!domain)
return -EINVAL;
if (type) {
if (convert_idna) {
r = dns_name_apply_idna(domain, &buf);
if (r < 0)
return r;
if (r > 0)
domain = buf;
}
r = dns_service_join(service, type, domain, &joined);
if (r < 0)
return r;
name = joined;
} else {
if (service)
return -EINVAL;
name = domain;
}
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, 0);
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, 0);
if (r < 0)
return r;
}
*ret = TAKE_PTR(q);
return 0;
}
/*
* This function is not used in the code base, but is useful when debugging. Do not delete.
*/
void dns_question_dump(DnsQuestion *question, FILE *f) {
DnsResourceKey *k;
if (!f)
f = stdout;
DNS_QUESTION_FOREACH(k, question) {
char buf[DNS_RESOURCE_KEY_STRING_MAX];
fputc('\t', f);
fputs(dns_resource_key_to_string(k, buf, sizeof(buf)), f);
fputc('\n', f);
}
}