[thirdparty/systemd.git] / src / resolve / resolved-dns-answer.c

/* SPDX-License-Identifier: LGPL-2.1+ */

#include "alloc-util.h"
#include "dns-domain.h"
#include "resolved-dns-answer.h"
#include "resolved-dns-dnssec.h"
#include "string-util.h"

DnsAnswer *dns_answer_new(size_t n) {
        DnsAnswer *a;

        a = malloc0(offsetof(DnsAnswer, items) + sizeof(DnsAnswerItem) * n);
        if (!a)
                return NULL;

        a->n_ref = 1;
        a->n_allocated = n;

        return a;
}

static void dns_answer_flush(DnsAnswer *a) {
        DnsResourceRecord *rr;

        if (!a)
                return;

        DNS_ANSWER_FOREACH(rr, a)
                dns_resource_record_unref(rr);

        a->n_rrs = 0;
}

static DnsAnswer *dns_answer_free(DnsAnswer *a) {
        assert(a);

        dns_answer_flush(a);
        return mfree(a);
}

DEFINE_TRIVIAL_REF_UNREF_FUNC(DnsAnswer, dns_answer, dns_answer_free);

static int dns_answer_add_raw(DnsAnswer *a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags) {
        assert(rr);

        if (!a)
                return -ENOSPC;

        if (a->n_rrs >= a->n_allocated)
                return -ENOSPC;

        a->items[a->n_rrs++] = (DnsAnswerItem) {
                .rr = dns_resource_record_ref(rr),
                .ifindex = ifindex,
                .flags = flags,
        };

        return 1;
}

static int dns_answer_add_raw_all(DnsAnswer *a, DnsAnswer *source) {
        DnsResourceRecord *rr;
        DnsAnswerFlags flags;
        int ifindex, r;

        DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, source) {
                r = dns_answer_add_raw(a, rr, ifindex, flags);
                if (r < 0)
                        return r;
        }

        return 0;
}

int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags) {
        size_t i;
        int r;

        assert(rr);

        if (!a)
                return -ENOSPC;
        if (a->n_ref > 1)
                return -EBUSY;

        for (i = 0; i < a->n_rrs; i++) {
                if (a->items[i].ifindex != ifindex)
                        continue;

                r = dns_resource_record_equal(a->items[i].rr, rr);
                if (r < 0)
                        return r;
                if (r > 0) {
                        /* Don't mix contradicting TTLs (see below) */
                        if ((rr->ttl == 0) != (a->items[i].rr->ttl == 0))
                                return -EINVAL;

                        /* Entry already exists, keep the entry with
                         * the higher RR. */
                        if (rr->ttl > a->items[i].rr->ttl) {
                                dns_resource_record_ref(rr);
                                dns_resource_record_unref(a->items[i].rr);
                                a->items[i].rr = rr;
                        }

                        a->items[i].flags |= flags;
                        return 0;
                }

                r = dns_resource_key_equal(a->items[i].rr->key, rr->key);
                if (r < 0)
                        return r;
                if (r > 0) {
                        /* There's already an RR of the same RRset in
                         * place! Let's see if the TTLs more or less
                         * match. We don't really care if they match
                         * precisely, but we do care whether one is 0
                         * and the other is not. See RFC 2181, Section
                         * 5.2. */

                        if ((rr->ttl == 0) != (a->items[i].rr->ttl == 0))
                                return -EINVAL;
                }
        }

        return dns_answer_add_raw(a, rr, ifindex, flags);
}

static int dns_answer_add_all(DnsAnswer *a, DnsAnswer *b) {
        DnsResourceRecord *rr;
        DnsAnswerFlags flags;
        int ifindex, r;

        DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, b) {
                r = dns_answer_add(a, rr, ifindex, flags);
                if (r < 0)
                        return r;
        }

        return 0;
}

int dns_answer_add_extend(DnsAnswer **a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags) {
        int r;

        assert(a);
        assert(rr);

        r = dns_answer_reserve_or_clone(a, 1);
        if (r < 0)
                return r;

        return dns_answer_add(*a, rr, ifindex, flags);
}

int dns_answer_add_soa(DnsAnswer *a, const char *name, uint32_t ttl, int ifindex) {
        _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *soa = NULL;

        soa = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_SOA, name);
        if (!soa)
                return -ENOMEM;

        soa->ttl = ttl;

        soa->soa.mname = strdup(name);
        if (!soa->soa.mname)
                return -ENOMEM;

        soa->soa.rname = strappend("root.", name);
        if (!soa->soa.rname)
                return -ENOMEM;

        soa->soa.serial = 1;
        soa->soa.refresh = 1;
        soa->soa.retry = 1;
        soa->soa.expire = 1;
        soa->soa.minimum = ttl;

        return dns_answer_add(a, soa, ifindex, DNS_ANSWER_AUTHENTICATED);
}

int dns_answer_match_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *ret_flags) {
        DnsAnswerFlags flags = 0, i_flags;
        DnsResourceRecord *i;
        bool found = false;
        int r;

        assert(key);

        DNS_ANSWER_FOREACH_FLAGS(i, i_flags, a) {
                r = dns_resource_key_match_rr(key, i, NULL);
                if (r < 0)
                        return r;
                if (r == 0)
                        continue;

                if (!ret_flags)
                        return 1;

                if (found)
                        flags &= i_flags;
                else {
                        flags = i_flags;
                        found = true;
                }
        }

        if (ret_flags)
                *ret_flags = flags;

        return found;
}

int dns_answer_contains_rr(DnsAnswer *a, DnsResourceRecord *rr, DnsAnswerFlags *ret_flags) {
        DnsAnswerFlags flags = 0, i_flags;
        DnsResourceRecord *i;
        bool found = false;
        int r;

        assert(rr);

        DNS_ANSWER_FOREACH_FLAGS(i, i_flags, a) {
                r = dns_resource_record_equal(i, rr);
                if (r < 0)
                        return r;
                if (r == 0)
                        continue;

                if (!ret_flags)
                        return 1;

                if (found)
                        flags &= i_flags;
                else {
                        flags = i_flags;
                        found = true;
                }
        }

        if (ret_flags)
                *ret_flags = flags;

        return found;
}

int dns_answer_contains_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *ret_flags) {
        DnsAnswerFlags flags = 0, i_flags;
        DnsResourceRecord *i;
        bool found = false;
        int r;

        assert(key);

        DNS_ANSWER_FOREACH_FLAGS(i, i_flags, a) {
                r = dns_resource_key_equal(i->key, key);
                if (r < 0)
                        return r;
                if (r == 0)
                        continue;

                if (!ret_flags)
                        return true;

                if (found)
                        flags &= i_flags;
                else {
                        flags = i_flags;
                        found = true;
                }
        }

        if (ret_flags)
                *ret_flags = flags;

        return found;
}

int dns_answer_contains_nsec_or_nsec3(DnsAnswer *a) {
        DnsResourceRecord *i;

        DNS_ANSWER_FOREACH(i, a) {
                if (IN_SET(i->key->type, DNS_TYPE_NSEC, DNS_TYPE_NSEC3))
                        return true;
        }

        return false;
}

int dns_answer_contains_zone_nsec3(DnsAnswer *answer, const char *zone) {
        DnsResourceRecord *rr;
        int r;

        /* Checks whether the specified answer contains at least one NSEC3 RR in the specified zone */

        DNS_ANSWER_FOREACH(rr, answer) {
                const char *p;

                if (rr->key->type != DNS_TYPE_NSEC3)
                        continue;

                p = dns_resource_key_name(rr->key);
                r = dns_name_parent(&p);
                if (r < 0)
                        return r;
                if (r == 0)
                        continue;

                r = dns_name_equal(p, zone);
                if (r != 0)
                        return r;
        }

        return false;
}

int dns_answer_find_soa(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags) {
        DnsResourceRecord *rr, *soa = NULL;
        DnsAnswerFlags rr_flags, soa_flags = 0;
        int r;

        assert(key);

        /* For a SOA record we can never find a matching SOA record */
        if (key->type == DNS_TYPE_SOA)
                return 0;

        DNS_ANSWER_FOREACH_FLAGS(rr, rr_flags, a) {
                r = dns_resource_key_match_soa(key, rr->key);
                if (r < 0)
                        return r;
                if (r > 0) {

                        if (soa) {
                                r = dns_name_endswith(dns_resource_key_name(rr->key), dns_resource_key_name(soa->key));
                                if (r < 0)
                                        return r;
                                if (r > 0)
                                        continue;
                        }

                        soa = rr;
                        soa_flags = rr_flags;
                }
        }

        if (!soa)
                return 0;

        if (ret)
                *ret = soa;
        if (flags)
                *flags = soa_flags;

        return 1;
}

int dns_answer_find_cname_or_dname(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags) {
        DnsResourceRecord *rr;
        DnsAnswerFlags rr_flags;
        int r;

        assert(key);

        /* 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;

        DNS_ANSWER_FOREACH_FLAGS(rr, rr_flags, a) {
                r = dns_resource_key_match_cname_or_dname(key, rr->key, NULL);
                if (r < 0)
                        return r;
                if (r > 0) {
                        if (ret)
                                *ret = rr;
                        if (flags)
                                *flags = rr_flags;
                        return 1;
                }
        }

        return 0;
}

int dns_answer_merge(DnsAnswer *a, DnsAnswer *b, DnsAnswer **ret) {
        _cleanup_(dns_answer_unrefp) DnsAnswer *k = NULL;
        int r;

        assert(ret);

        if (dns_answer_size(a) <= 0) {
                *ret = dns_answer_ref(b);
                return 0;
        }

        if (dns_answer_size(b) <= 0) {
                *ret = dns_answer_ref(a);
                return 0;
        }

        k = dns_answer_new(a->n_rrs + b->n_rrs);
        if (!k)
                return -ENOMEM;

        r = dns_answer_add_raw_all(k, a);
        if (r < 0)
                return r;

        r = dns_answer_add_all(k, b);
        if (r < 0)
                return r;

        *ret = TAKE_PTR(k);

        return 0;
}

int dns_answer_extend(DnsAnswer **a, DnsAnswer *b) {
        DnsAnswer *merged;
        int r;

        assert(a);

        r = dns_answer_merge(*a, b, &merged);
        if (r < 0)
                return r;

        dns_answer_unref(*a);
        *a = merged;

        return 0;
}

int dns_answer_remove_by_key(DnsAnswer **a, const DnsResourceKey *key) {
        bool found = false, other = false;
        DnsResourceRecord *rr;
        size_t i;
        int r;

        assert(a);
        assert(key);

        /* Remove all entries matching the specified key from *a */

        DNS_ANSWER_FOREACH(rr, *a) {
                r = dns_resource_key_equal(rr->key, key);
                if (r < 0)
                        return r;
                if (r > 0)
                        found = true;
                else
                        other = true;

                if (found && other)
                        break;
        }

        if (!found)
                return 0;

        if (!other) {
                *a = dns_answer_unref(*a); /* Return NULL for the empty answer */
                return 1;
        }

        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_key_equal(rr->key, key);
                        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 = TAKE_PTR(copy);

                return 1;
        }

        /* Only a single reference, edit in-place */

        i = 0;
        for (;;) {
                if (i >= (*a)->n_rrs)
                        break;

                r = dns_resource_key_equal((*a)->items[i].rr->key, key);
                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_remove_by_rr(DnsAnswer **a, DnsResourceRecord *rm) {
        bool found = false, other = false;
        DnsResourceRecord *rr;
        size_t i;
        int r;

        assert(a);
        assert(rm);

        /* Remove all entries matching the specified RR from *a */

        DNS_ANSWER_FOREACH(rr, *a) {
                r = dns_resource_record_equal(rr, rm);
                if (r < 0)
                        return r;
                if (r > 0)
                        found = true;
                else
                        other = true;

                if (found && other)
                        break;
        }

        if (!found)
                return 0;

        if (!other) {
                *a = dns_answer_unref(*a); /* Return NULL for the empty answer */
                return 1;
        }

        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 = TAKE_PTR(copy);

                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;
        size_t 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, size_t n_free) {
        DnsAnswer *n;

        assert(a);

        if (n_free <= 0)
                return 0;

        if (*a) {
                size_t 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, size_t 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 = TAKE_PTR(n);

        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);
        }
}

int 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;
}
Commit	Line	Data
53e1b683	1	/* SPDX-License-Identifier: LGPL-2.1+ */
faa133f3	2
b5efdb8a	3	#include "alloc-util.h"
4ad7f276	4	#include "dns-domain.h"
07630cea	5	#include "resolved-dns-answer.h"
72667f08	6	#include "resolved-dns-dnssec.h"
07630cea	7	#include "string-util.h"
faa133f3	8
da6053d0	9	DnsAnswer *dns_answer_new(size_t n) {
faa133f3 LP	10	DnsAnswer *a;
faa133f3 LP	11
78c6a153	12	a = malloc0(offsetof(DnsAnswer, items) + sizeof(DnsAnswerItem) * n);
faa133f3 LP	13	if (!a)
	14	return NULL;
	15
	16	a->n_ref = 1;
	17	a->n_allocated = n;
	18
	19	return a;
	20	}
	21
d42800f1 LP	22	static void dns_answer_flush(DnsAnswer *a) {
	23	DnsResourceRecord *rr;
	24
	25	if (!a)
	26	return;
	27
	28	DNS_ANSWER_FOREACH(rr, a)
	29	dns_resource_record_unref(rr);
	30
	31	a->n_rrs = 0;
	32	}
	33
8301aa0b YW	34	static DnsAnswer dns_answer_free(DnsAnswer a) {
8301aa0b YW	35	assert(a);
faa133f3	36
8301aa0b YW	37	dns_answer_flush(a);
8301aa0b YW	38	return mfree(a);
faa133f3 LP	39	}
faa133f3 LP	40
8301aa0b YW	41	DEFINE_TRIVIAL_REF_UNREF_FUNC(DnsAnswer, dns_answer, dns_answer_free);
8301aa0b YW	42
105e1512	43	static int dns_answer_add_raw(DnsAnswer a, DnsResourceRecord rr, int ifindex, DnsAnswerFlags flags) {
547973de LP	44	assert(rr);
	45
	46	if (!a)
	47	return -ENOSPC;
	48
	49	if (a->n_rrs >= a->n_allocated)
	50	return -ENOSPC;
	51
105e1512 LP	52	a->items[a->n_rrs++] = (DnsAnswerItem) {
	53	.rr = dns_resource_record_ref(rr),
	54	.ifindex = ifindex,
	55	.flags = flags,
	56	};
547973de LP	57
	58	return 1;
	59	}
	60
	61	static int dns_answer_add_raw_all(DnsAnswer a, DnsAnswer source) {
	62	DnsResourceRecord *rr;
105e1512	63	DnsAnswerFlags flags;
547973de LP	64	int ifindex, r;
547973de LP	65
105e1512 LP	66	DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, source) {
105e1512 LP	67	r = dns_answer_add_raw(a, rr, ifindex, flags);
547973de LP	68	if (r < 0)
	69	return r;
	70	}
	71
	72	return 0;
	73	}
	74
105e1512	75	int dns_answer_add(DnsAnswer a, DnsResourceRecord rr, int ifindex, DnsAnswerFlags flags) {
da6053d0	76	size_t i;
7e8e0422 LP	77	int r;
7e8e0422 LP	78
faa133f3 LP	79	assert(rr);
faa133f3 LP	80
78c6a153 LP	81	if (!a)
78c6a153 LP	82	return -ENOSPC;
c296dd2e LP	83	if (a->n_ref > 1)
c296dd2e LP	84	return -EBUSY;
78c6a153	85
7e8e0422	86	for (i = 0; i < a->n_rrs; i++) {
78c6a153 LP	87	if (a->items[i].ifindex != ifindex)
	88	continue;
	89
	90	r = dns_resource_record_equal(a->items[i].rr, rr);
7e8e0422 LP	91	if (r < 0)
	92	return r;
	93	if (r > 0) {
7feea00b LP	94	/* Don't mix contradicting TTLs (see below) */
	95	if ((rr->ttl == 0) != (a->items[i].rr->ttl == 0))
	96	return -EINVAL;
7e8e0422	97
7feea00b LP	98	/* Entry already exists, keep the entry with
	99	* the higher RR. */
	100	if (rr->ttl > a->items[i].rr->ttl) {
7e8e0422	101	dns_resource_record_ref(rr);
78c6a153 LP	102	dns_resource_record_unref(a->items[i].rr);
78c6a153 LP	103	a->items[i].rr = rr;
7e8e0422 LP	104	}
7e8e0422 LP	105
105e1512	106	a->items[i].flags \|= flags;
7e8e0422 LP	107	return 0;
7e8e0422 LP	108	}
7feea00b LP	109
	110	r = dns_resource_key_equal(a->items[i].rr->key, rr->key);
	111	if (r < 0)
	112	return r;
	113	if (r > 0) {
	114	/* There's already an RR of the same RRset in
	115	* place! Let's see if the TTLs more or less
	116	* match. We don't really care if they match
	117	* precisely, but we do care whether one is 0
	118	* and the other is not. See RFC 2181, Section
13e785f7	119	* 5.2. */
7feea00b LP	120
	121	if ((rr->ttl == 0) != (a->items[i].rr->ttl == 0))
	122	return -EINVAL;
	123	}
7e8e0422 LP	124	}
7e8e0422 LP	125
105e1512	126	return dns_answer_add_raw(a, rr, ifindex, flags);
547973de	127	}
faa133f3	128
547973de LP	129	static int dns_answer_add_all(DnsAnswer a, DnsAnswer b) {
547973de LP	130	DnsResourceRecord *rr;
105e1512	131	DnsAnswerFlags flags;
547973de	132	int ifindex, r;
78c6a153	133
105e1512 LP	134	DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, b) {
105e1512 LP	135	r = dns_answer_add(a, rr, ifindex, flags);
547973de LP	136	if (r < 0)
	137	return r;
	138	}
	139
	140	return 0;
	141	}
	142
105e1512	143	int dns_answer_add_extend(DnsAnswer *a, DnsResourceRecord rr, int ifindex, DnsAnswerFlags flags) {
547973de LP	144	int r;
	145
	146	assert(a);
	147	assert(rr);
	148
	149	r = dns_answer_reserve_or_clone(a, 1);
	150	if (r < 0)
	151	return r;
	152
105e1512	153	return dns_answer_add(*a, rr, ifindex, flags);
7e8e0422 LP	154	}
7e8e0422 LP	155
97ebebbc	156	int dns_answer_add_soa(DnsAnswer a, const char name, uint32_t ttl, int ifindex) {
8bf52d3d LP	157	_cleanup_(dns_resource_record_unrefp) DnsResourceRecord *soa = NULL;
	158
	159	soa = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_SOA, name);
	160	if (!soa)
	161	return -ENOMEM;
	162
57f5ad31 LP	163	soa->ttl = ttl;
57f5ad31 LP	164
8bf52d3d LP	165	soa->soa.mname = strdup(name);
	166	if (!soa->soa.mname)
	167	return -ENOMEM;
	168
	169	soa->soa.rname = strappend("root.", name);
	170	if (!soa->soa.rname)
	171	return -ENOMEM;
	172
	173	soa->soa.serial = 1;
	174	soa->soa.refresh = 1;
	175	soa->soa.retry = 1;
	176	soa->soa.expire = 1;
57f5ad31	177	soa->soa.minimum = ttl;
8bf52d3d	178
97ebebbc	179	return dns_answer_add(a, soa, ifindex, DNS_ANSWER_AUTHENTICATED);
8bf52d3d LP	180	}
8bf52d3d LP	181
105e1512 LP	182	int dns_answer_match_key(DnsAnswer a, const DnsResourceKey key, DnsAnswerFlags *ret_flags) {
105e1512 LP	183	DnsAnswerFlags flags = 0, i_flags;
547973de	184	DnsResourceRecord *i;
105e1512	185	bool found = false;
7e8e0422 LP	186	int r;
7e8e0422 LP	187
7e8e0422 LP	188	assert(key);
7e8e0422 LP	189
105e1512	190	DNS_ANSWER_FOREACH_FLAGS(i, i_flags, a) {
547973de	191	r = dns_resource_key_match_rr(key, i, NULL);
7e8e0422 LP	192	if (r < 0)
7e8e0422 LP	193	return r;
105e1512 LP	194	if (r == 0)
	195	continue;
	196
	197	if (!ret_flags)
7e8e0422	198	return 1;
105e1512 LP	199
	200	if (found)
	201	flags &= i_flags;
	202	else {
	203	flags = i_flags;
	204	found = true;
	205	}
7e8e0422 LP	206	}
7e8e0422 LP	207
105e1512 LP	208	if (ret_flags)
	209	*ret_flags = flags;
	210
	211	return found;
7e8e0422 LP	212	}
7e8e0422 LP	213
105e1512 LP	214	int dns_answer_contains_rr(DnsAnswer a, DnsResourceRecord rr, DnsAnswerFlags *ret_flags) {
105e1512 LP	215	DnsAnswerFlags flags = 0, i_flags;
547973de	216	DnsResourceRecord *i;
105e1512	217	bool found = false;
547973de	218	int r;
5eefe544	219
547973de	220	assert(rr);
5eefe544	221
105e1512	222	DNS_ANSWER_FOREACH_FLAGS(i, i_flags, a) {
547973de LP	223	r = dns_resource_record_equal(i, rr);
	224	if (r < 0)
	225	return r;
105e1512 LP	226	if (r == 0)
	227	continue;
	228
	229	if (!ret_flags)
547973de	230	return 1;
105e1512 LP	231
	232	if (found)
	233	flags &= i_flags;
	234	else {
	235	flags = i_flags;
	236	found = true;
	237	}
547973de	238	}
5eefe544	239
105e1512 LP	240	if (ret_flags)
	241	*ret_flags = flags;
	242
	243	return found;
	244	}
	245
	246	int dns_answer_contains_key(DnsAnswer a, const DnsResourceKey key, DnsAnswerFlags *ret_flags) {
	247	DnsAnswerFlags flags = 0, i_flags;
	248	DnsResourceRecord *i;
	249	bool found = false;
	250	int r;
	251
	252	assert(key);
	253
	254	DNS_ANSWER_FOREACH_FLAGS(i, i_flags, a) {
	255	r = dns_resource_key_equal(i->key, key);
	256	if (r < 0)
	257	return r;
	258	if (r == 0)
	259	continue;
	260
	261	if (!ret_flags)
	262	return true;
	263
	264	if (found)
	265	flags &= i_flags;
	266	else {
	267	flags = i_flags;
	268	found = true;
	269	}
	270	}
	271
	272	if (ret_flags)
	273	*ret_flags = flags;
	274
	275	return found;
	276	}
	277
	278	int dns_answer_contains_nsec_or_nsec3(DnsAnswer *a) {
	279	DnsResourceRecord *i;
	280
	281	DNS_ANSWER_FOREACH(i, a) {
	282	if (IN_SET(i->key->type, DNS_TYPE_NSEC, DNS_TYPE_NSEC3))
	283	return true;
	284	}
	285
	286	return false;
5eefe544 TG	287	}
5eefe544 TG	288
e926785a LP	289	int dns_answer_contains_zone_nsec3(DnsAnswer answer, const char zone) {
	290	DnsResourceRecord *rr;
	291	int r;
	292
	293	/* Checks whether the specified answer contains at least one NSEC3 RR in the specified zone */
	294
	295	DNS_ANSWER_FOREACH(rr, answer) {
	296	const char *p;
	297
	298	if (rr->key->type != DNS_TYPE_NSEC3)
	299	continue;
	300
1c02e7ba	301	p = dns_resource_key_name(rr->key);
e926785a LP	302	r = dns_name_parent(&p);
	303	if (r < 0)
	304	return r;
	305	if (r == 0)
	306	continue;
	307
	308	r = dns_name_equal(p, zone);
	309	if (r != 0)
	310	return r;
	311	}
	312
	313	return false;
	314	}
	315
fd009cd8	316	int dns_answer_find_soa(DnsAnswer a, const DnsResourceKey key, DnsResourceRecord *ret, DnsAnswerFlags flags) {
81f7fc5e LP	317	DnsResourceRecord rr, soa = NULL;
81f7fc5e LP	318	DnsAnswerFlags rr_flags, soa_flags = 0;
29c1519e	319	int r;
7e8e0422	320
7e8e0422	321	assert(key);
7e8e0422	322
0f05c387 LP	323	/* For a SOA record we can never find a matching SOA record */
	324	if (key->type == DNS_TYPE_SOA)
	325	return 0;
	326
fd009cd8	327	DNS_ANSWER_FOREACH_FLAGS(rr, rr_flags, a) {
29c1519e LP	328	r = dns_resource_key_match_soa(key, rr->key);
	329	if (r < 0)
	330	return r;
	331	if (r > 0) {
81f7fc5e LP	332
81f7fc5e LP	333	if (soa) {
1c02e7ba	334	r = dns_name_endswith(dns_resource_key_name(rr->key), dns_resource_key_name(soa->key));
81f7fc5e LP	335	if (r < 0)
	336	return r;
	337	if (r > 0)
	338	continue;
	339	}
	340
	341	soa = rr;
	342	soa_flags = rr_flags;
7e8e0422 LP	343	}
	344	}
	345
81f7fc5e LP	346	if (!soa)
	347	return 0;
	348
	349	if (ret)
	350	*ret = soa;
	351	if (flags)
	352	*flags = soa_flags;
	353
	354	return 1;
faa133f3	355	}
934e9b10	356
105e1512	357	int dns_answer_find_cname_or_dname(DnsAnswer a, const DnsResourceKey key, DnsResourceRecord *ret, DnsAnswerFlags flags) {
5d27351f	358	DnsResourceRecord *rr;
105e1512	359	DnsAnswerFlags rr_flags;
29c1519e	360	int r;
5d27351f TG	361
	362	assert(key);
	363
5d27351f	364	/* For a {C,D}NAME record we can never find a matching {C,D}NAME record */
6b2f7093	365	if (!dns_type_may_redirect(key->type))
5d27351f TG	366	return 0;
5d27351f TG	367
105e1512	368	DNS_ANSWER_FOREACH_FLAGS(rr, rr_flags, a) {
29c1519e LP	369	r = dns_resource_key_match_cname_or_dname(key, rr->key, NULL);
	370	if (r < 0)
	371	return r;
	372	if (r > 0) {
5d27351f TG	373	if (ret)
5d27351f TG	374	*ret = rr;
105e1512 LP	375	if (flags)
105e1512 LP	376	*flags = rr_flags;
5d27351f TG	377	return 1;
	378	}
	379	}
	380
	381	return 0;
	382	}
	383
547973de LP	384	int dns_answer_merge(DnsAnswer a, DnsAnswer b, DnsAnswer **ret) {
	385	_cleanup_(dns_answer_unrefp) DnsAnswer *k = NULL;
	386	int r;
	387
	388	assert(ret);
	389
	390	if (dns_answer_size(a) <= 0) {
	391	*ret = dns_answer_ref(b);
	392	return 0;
	393	}
	394
	395	if (dns_answer_size(b) <= 0) {
	396	*ret = dns_answer_ref(a);
	397	return 0;
	398	}
	399
	400	k = dns_answer_new(a->n_rrs + b->n_rrs);
	401	if (!k)
	402	return -ENOMEM;
	403
	404	r = dns_answer_add_raw_all(k, a);
	405	if (r < 0)
	406	return r;
	407
	408	r = dns_answer_add_all(k, b);
	409	if (r < 0)
	410	return r;
	411
1cc6c93a	412	*ret = TAKE_PTR(k);
547973de LP	413
	414	return 0;
	415	}
	416
	417	int dns_answer_extend(DnsAnswer *a, DnsAnswer b) {
	418	DnsAnswer *merged;
	419	int r;
	420
	421	assert(a);
	422
	423	r = dns_answer_merge(*a, b, &merged);
	424	if (r < 0)
	425	return r;
	426
	427	dns_answer_unref(*a);
	428	*a = merged;
	429
	430	return 0;
	431	}
	432
	433	int dns_answer_remove_by_key(DnsAnswer *a, const DnsResourceKey key) {
	434	bool found = false, other = false;
	435	DnsResourceRecord *rr;
da6053d0	436	size_t i;
934e9b10 LP	437	int r;
934e9b10 LP	438
547973de LP	439	assert(a);
547973de LP	440	assert(key);
934e9b10	441
547973de	442	/* Remove all entries matching the specified key from a /
934e9b10	443
547973de LP	444	DNS_ANSWER_FOREACH(rr, *a) {
	445	r = dns_resource_key_equal(rr->key, key);
	446	if (r < 0)
	447	return r;
	448	if (r > 0)
	449	found = true;
	450	else
	451	other = true;
	452
	453	if (found && other)
	454	break;
	455	}
	456
	457	if (!found)
	458	return 0;
	459
	460	if (!other) {
	461	a = dns_answer_unref(a); /* Return NULL for the empty answer */
	462	return 1;
934e9b10 LP	463	}
934e9b10 LP	464
547973de LP	465	if ((*a)->n_ref > 1) {
547973de LP	466	_cleanup_(dns_answer_unrefp) DnsAnswer *copy = NULL;
105e1512	467	DnsAnswerFlags flags;
547973de LP	468	int ifindex;
	469
	470	copy = dns_answer_new((*a)->n_rrs);
	471	if (!copy)
	472	return -ENOMEM;
	473
105e1512	474	DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, *a) {
547973de	475	r = dns_resource_key_equal(rr->key, key);
934e9b10	476	if (r < 0)
547973de LP	477	return r;
	478	if (r > 0)
	479	continue;
	480
105e1512	481	r = dns_answer_add_raw(copy, rr, ifindex, flags);
547973de LP	482	if (r < 0)
547973de LP	483	return r;
934e9b10	484	}
547973de LP	485
547973de LP	486	dns_answer_unref(*a);
1cc6c93a	487	*a = TAKE_PTR(copy);
547973de LP	488
	489	return 1;
	490	}
	491
	492	/* Only a single reference, edit in-place */
	493
	494	i = 0;
	495	for (;;) {
	496	if (i >= (*a)->n_rrs)
	497	break;
	498
	499	r = dns_resource_key_equal((*a)->items[i].rr->key, key);
	500	if (r < 0)
	501	return r;
	502	if (r > 0) {
	503	/* Kill this entry */
	504
	505	dns_resource_record_unref((*a)->items[i].rr);
	506	memmove((a)->items + i, (a)->items + i + 1, sizeof(DnsAnswerItem) * ((*a)->n_rrs - i - 1));
313cefa1	507	(*a)->n_rrs--;
547973de LP	508	continue;
	509
	510	} else
	511	/* Keep this entry */
	512	i++;
934e9b10 LP	513	}
934e9b10 LP	514
547973de LP	515	return 1;
	516	}
	517
0c857028 LP	518	int dns_answer_remove_by_rr(DnsAnswer *a, DnsResourceRecord rm) {
	519	bool found = false, other = false;
	520	DnsResourceRecord *rr;
da6053d0	521	size_t i;
0c857028 LP	522	int r;
	523
	524	assert(a);
	525	assert(rm);
	526
	527	/* Remove all entries matching the specified RR from a /
	528
	529	DNS_ANSWER_FOREACH(rr, *a) {
	530	r = dns_resource_record_equal(rr, rm);
	531	if (r < 0)
	532	return r;
	533	if (r > 0)
	534	found = true;
	535	else
	536	other = true;
	537
	538	if (found && other)
	539	break;
	540	}
	541
	542	if (!found)
	543	return 0;
	544
	545	if (!other) {
	546	a = dns_answer_unref(a); /* Return NULL for the empty answer */
	547	return 1;
	548	}
	549
	550	if ((*a)->n_ref > 1) {
	551	_cleanup_(dns_answer_unrefp) DnsAnswer *copy = NULL;
	552	DnsAnswerFlags flags;
	553	int ifindex;
	554
	555	copy = dns_answer_new((*a)->n_rrs);
	556	if (!copy)
	557	return -ENOMEM;
	558
	559	DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, *a) {
	560	r = dns_resource_record_equal(rr, rm);
	561	if (r < 0)
	562	return r;
	563	if (r > 0)
	564	continue;
	565
	566	r = dns_answer_add_raw(copy, rr, ifindex, flags);
	567	if (r < 0)
	568	return r;
	569	}
	570
	571	dns_answer_unref(*a);
1cc6c93a	572	*a = TAKE_PTR(copy);
0c857028 LP	573
	574	return 1;
	575	}
	576
	577	/* Only a single reference, edit in-place */
	578
	579	i = 0;
	580	for (;;) {
	581	if (i >= (*a)->n_rrs)
	582	break;
	583
	584	r = dns_resource_record_equal((*a)->items[i].rr, rm);
	585	if (r < 0)
	586	return r;
	587	if (r > 0) {
	588	/* Kill this entry */
	589
	590	dns_resource_record_unref((*a)->items[i].rr);
	591	memmove((a)->items + i, (a)->items + i + 1, sizeof(DnsAnswerItem) * ((*a)->n_rrs - i - 1));
313cefa1	592	(*a)->n_rrs--;
0c857028 LP	593	continue;
	594
	595	} else
	596	/* Keep this entry */
	597	i++;
	598	}
	599
	600	return 1;
	601	}
	602
105e1512	603	int dns_answer_copy_by_key(DnsAnswer *a, DnsAnswer source, const DnsResourceKey *key, DnsAnswerFlags or_flags) {
547973de LP	604	DnsResourceRecord *rr_source;
547973de LP	605	int ifindex_source, r;
105e1512	606	DnsAnswerFlags flags_source;
547973de LP	607
	608	assert(a);
	609	assert(key);
	610
	611	/* Copy all RRs matching the specified key from source into a /
	612
105e1512	613	DNS_ANSWER_FOREACH_FULL(rr_source, ifindex_source, flags_source, source) {
547973de LP	614
	615	r = dns_resource_key_equal(rr_source->key, key);
	616	if (r < 0)
	617	return r;
	618	if (r == 0)
	619	continue;
	620
	621	/* Make space for at least one entry */
	622	r = dns_answer_reserve_or_clone(a, 1);
	623	if (r < 0)
	624	return r;
934e9b10	625
105e1512	626	r = dns_answer_add(*a, rr_source, ifindex_source, flags_source\|or_flags);
547973de LP	627	if (r < 0)
	628	return r;
	629	}
	630
	631	return 0;
934e9b10	632	}
af93291c	633
105e1512 LP	634	int dns_answer_move_by_key(DnsAnswer to, DnsAnswer from, const DnsResourceKey *key, DnsAnswerFlags or_flags) {
	635	int r;
	636
	637	assert(to);
	638	assert(from);
	639	assert(key);
	640
	641	r = dns_answer_copy_by_key(to, *from, key, or_flags);
	642	if (r < 0)
	643	return r;
	644
	645	return dns_answer_remove_by_key(from, key);
	646	}
	647
af93291c	648	void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local) {
78c6a153	649	DnsAnswerItem *items;
da6053d0	650	size_t i, start, end;
78c6a153 LP	651
	652	if (!a)
	653	return;
af93291c LP	654
	655	if (a->n_rrs <= 1)
	656	return;
	657
	658	start = 0;
	659	end = a->n_rrs-1;
	660
	661	/* RFC 4795, Section 2.6 suggests we should order entries
	662	* depending on whether the sender is a link-local address. */
	663
78c6a153	664	items = newa(DnsAnswerItem, a->n_rrs);
af93291c LP	665	for (i = 0; i < a->n_rrs; i++) {
af93291c LP	666
78c6a153 LP	667	if (a->items[i].rr->key->class == DNS_CLASS_IN &&
	668	((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) \|\|
	669	(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)))
61233823	670	/* Order address records that are not preferred to the end of the array */
78c6a153	671	items[end--] = a->items[i];
af93291c LP	672	else
af93291c LP	673	/* Order all other records to the beginning of the array */
78c6a153	674	items[start++] = a->items[i];
af93291c LP	675	}
	676
	677	assert(start == end+1);
78c6a153 LP	678	memcpy(a->items, items, sizeof(DnsAnswerItem) * a->n_rrs);
	679	}
	680
da6053d0	681	int dns_answer_reserve(DnsAnswer **a, size_t n_free) {
78c6a153 LP	682	DnsAnswer *n;
78c6a153 LP	683
2f763887 LP	684	assert(a);
2f763887 LP	685
78c6a153 LP	686	if (n_free <= 0)
	687	return 0;
	688
	689	if (*a) {
da6053d0	690	size_t ns;
78c6a153 LP	691
	692	if ((*a)->n_ref > 1)
	693	return -EBUSY;
	694
	695	ns = (*a)->n_rrs + n_free;
	696
	697	if ((*a)->n_allocated >= ns)
	698	return 0;
	699
2f763887 LP	700	/* Allocate more than we need */
	701	ns *= 2;
	702
78c6a153 LP	703	n = realloc(a, offsetof(DnsAnswer, items) + sizeof(DnsAnswerItem) ns);
	704	if (!n)
	705	return -ENOMEM;
	706
	707	n->n_allocated = ns;
	708	} else {
	709	n = dns_answer_new(n_free);
	710	if (!n)
	711	return -ENOMEM;
	712	}
	713
	714	*a = n;
	715	return 0;
af93291c	716	}
547973de	717
da6053d0	718	int dns_answer_reserve_or_clone(DnsAnswer **a, size_t n_free) {
547973de LP	719	_cleanup_(dns_answer_unrefp) DnsAnswer *n = NULL;
	720	int r;
	721
	722	assert(a);
	723
	724	/* Tries to extend the DnsAnswer object. And if that's not
96d49011	725	* possible, since we are not the sole owner, then allocate a
547973de LP	726	* new, appropriately sized one. Either way, after this call
	727	* the object will only have a single reference, and has room
	728	* for at least the specified number of RRs. */
	729
	730	r = dns_answer_reserve(a, n_free);
	731	if (r != -EBUSY)
	732	return r;
	733
	734	assert(*a);
	735
	736	n = dns_answer_new(((a)->n_rrs + n_free) 2);
	737	if (!n)
	738	return -ENOMEM;
	739
	740	r = dns_answer_add_raw_all(n, *a);
	741	if (r < 0)
	742	return r;
	743
	744	dns_answer_unref(*a);
1cc6c93a	745	*a = TAKE_PTR(n);
547973de LP	746
	747	return 0;
	748	}
26156910 LP	749
	750	void dns_answer_dump(DnsAnswer answer, FILE f) {
	751	DnsResourceRecord *rr;
	752	DnsAnswerFlags flags;
7b50eb2e	753	int ifindex;
26156910 LP	754
	755	if (!f)
	756	f = stdout;
	757
	758	DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, answer) {
7b50eb2e	759	const char *t;
26156910 LP	760
	761	fputc('\t', f);
	762
7b50eb2e LP	763	t = dns_resource_record_to_string(rr);
7b50eb2e LP	764	if (!t) {
26156910 LP	765	log_oom();
	766	continue;
	767	}
	768
	769	fputs(t, f);
	770
	771	if (ifindex != 0 \|\| flags & (DNS_ANSWER_AUTHENTICATED\|DNS_ANSWER_CACHEABLE\|DNS_ANSWER_SHARED_OWNER))
	772	fputs("\t;", f);
	773
	774	if (ifindex != 0)
	775	printf(" ifindex=%i", ifindex);
	776	if (flags & DNS_ANSWER_AUTHENTICATED)
	777	fputs(" authenticated", f);
	778	if (flags & DNS_ANSWER_CACHEABLE)
	779	fputs(" cachable", f);
	780	if (flags & DNS_ANSWER_SHARED_OWNER)
	781	fputs(" shared-owner", f);
	782
	783	fputc('\n', f);
	784	}
	785	}
43e6779a	786
a5042ec4	787	int dns_answer_has_dname_for_cname(DnsAnswer a, DnsResourceRecord cname) {
43e6779a LP	788	DnsResourceRecord *rr;
	789	int r;
	790
	791	assert(cname);
	792
	793	/* Checks whether the answer contains a DNAME record that indicates that the specified CNAME record is
	794	* synthesized from it */
	795
	796	if (cname->key->type != DNS_TYPE_CNAME)
	797	return 0;
	798
	799	DNS_ANSWER_FOREACH(rr, a) {
	800	_cleanup_free_ char *n = NULL;
	801
	802	if (rr->key->type != DNS_TYPE_DNAME)
	803	continue;
	804	if (rr->key->class != cname->key->class)
	805	continue;
	806
1c02e7ba	807	r = dns_name_change_suffix(cname->cname.name, rr->dname.name, dns_resource_key_name(rr->key), &n);
43e6779a LP	808	if (r < 0)
	809	return r;
	810	if (r == 0)
	811	continue;
	812
1c02e7ba	813	r = dns_name_equal(n, dns_resource_key_name(cname->key));
43e6779a LP	814	if (r < 0)
	815	return r;
	816	if (r > 0)
	817	return 1;
43e6779a LP	818	}
	819
	820	return 0;
	821	}