| /*** |
| 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 "dns-type.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, const char *search_domain) { |
| 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, search_domain); |
| if (r != 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| int dns_question_matches_cname_or_dname(DnsQuestion *q, DnsResourceRecord *rr, const char *search_domain) { |
| unsigned i; |
| int r; |
| |
| assert(rr); |
| |
| if (!q) |
| return 0; |
| |
| if (!IN_SET(rr->key->type, DNS_TYPE_CNAME, DNS_TYPE_DNAME)) |
| return 0; |
| |
| for (i = 0; i < q->n_keys; i++) { |
| /* For a {C,D}NAME record we can never find a matching {C,D}NAME record */ |
| if (!dns_type_may_redirect(q->keys[i]->type)) |
| return 0; |
| |
| r = dns_resource_key_match_cname_or_dname(q->keys[i], rr->key, search_domain); |
| if (r != 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| int dns_question_is_valid_for_query(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 = 0; i < q->n_keys; i++) { |
| assert(q->keys[i]); |
| |
| if (i > 0) { |
| r = dns_name_equal(dns_resource_key_name(q->keys[i]), name); |
| if (r <= 0) |
| return r; |
| } |
| |
| if (!dns_type_is_valid_query(q->keys[i]->type)) |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| int dns_question_contains(DnsQuestion *a, const 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 == b) |
| return 1; |
| |
| 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; |
| 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); |
| if (r < 0) |
| return r; |
| } |
| |
| *ret = n; |
| n = NULL; |
| |
| 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->keys[0]); |
| } |
| |
| 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; |
| |
| name = buf; |
| } |
| |
| 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 *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; |
| |
| 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); |
| 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; |
| } |