| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include <stdio.h> |
| |
| #include "alloc-util.h" |
| #include "dns-domain.h" |
| #include "random-util.h" |
| #include "resolved-dns-answer.h" |
| #include "resolved-dns-dnssec.h" |
| #include "string-util.h" |
| |
| static void dns_answer_item_hash_func(const DnsAnswerItem *a, struct siphash *state) { |
| assert(a); |
| assert(state); |
| |
| siphash24_compress(&a->ifindex, sizeof(a->ifindex), state); |
| |
| dns_resource_record_hash_func(a->rr, state); |
| } |
| |
| static int dns_answer_item_compare_func(const DnsAnswerItem *a, const DnsAnswerItem *b) { |
| int r; |
| |
| assert(a); |
| assert(b); |
| |
| r = CMP(a->ifindex, b->ifindex); |
| if (r != 0) |
| return r; |
| |
| return dns_resource_record_compare_func(a->rr, b->rr); |
| } |
| |
| DEFINE_PRIVATE_HASH_OPS(dns_answer_item_hash_ops, DnsAnswerItem, dns_answer_item_hash_func, dns_answer_item_compare_func); |
| |
| DnsAnswer *dns_answer_new(size_t n) { |
| _cleanup_set_free_ Set *s = NULL; |
| DnsAnswer *a; |
| |
| if (n > UINT16_MAX) /* We can only place 64K RRs in an answer at max */ |
| n = UINT16_MAX; |
| |
| s = set_new(&dns_answer_item_hash_ops); |
| if (!s) |
| return NULL; |
| |
| /* Higher multipliers give slightly higher efficiency through hash collisions, but the gains |
| * quickly drop off after 2. */ |
| if (set_reserve(s, n * 2) < 0) |
| return NULL; |
| |
| a = malloc0(offsetof(DnsAnswer, items) + sizeof(DnsAnswerItem) * n); |
| if (!a) |
| return NULL; |
| |
| a->n_ref = 1; |
| a->n_allocated = n; |
| a->set_items = TAKE_PTR(s); |
| return a; |
| } |
| |
| static void dns_answer_flush(DnsAnswer *a) { |
| DnsAnswerItem *item; |
| |
| if (!a) |
| return; |
| |
| a->set_items = set_free(a->set_items); |
| |
| DNS_ANSWER_FOREACH_ITEM(item, a) { |
| dns_resource_record_unref(item->rr); |
| dns_resource_record_unref(item->rrsig); |
| } |
| |
| 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, |
| DnsResourceRecord *rrsig) { |
| |
| int r; |
| |
| assert(rr); |
| |
| if (!a) |
| return -ENOSPC; |
| |
| if (a->n_rrs >= a->n_allocated) |
| return -ENOSPC; |
| |
| a->items[a->n_rrs] = (DnsAnswerItem) { |
| .rr = rr, |
| .ifindex = ifindex, |
| .flags = flags, |
| .rrsig = dns_resource_record_ref(rrsig), |
| }; |
| |
| r = set_put(a->set_items, &a->items[a->n_rrs]); |
| if (r < 0) |
| return r; |
| if (r == 0) |
| return -EEXIST; |
| |
| dns_resource_record_ref(rr); |
| a->n_rrs++; |
| |
| return 1; |
| } |
| |
| static int dns_answer_add_raw_all(DnsAnswer *a, DnsAnswer *source) { |
| DnsAnswerItem *item; |
| int r; |
| |
| DNS_ANSWER_FOREACH_ITEM(item, source) { |
| r = dns_answer_add_raw( |
| a, |
| item->rr, |
| item->ifindex, |
| item->flags, |
| item->rrsig); |
| if (r < 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| int dns_answer_add( |
| DnsAnswer *a, |
| DnsResourceRecord *rr, |
| int ifindex, |
| DnsAnswerFlags flags, |
| DnsResourceRecord *rrsig) { |
| |
| DnsAnswerItem tmp, *exist; |
| |
| assert(rr); |
| |
| if (!a) |
| return -ENOSPC; |
| if (a->n_ref > 1) |
| return -EBUSY; |
| |
| tmp = (DnsAnswerItem) { |
| .rr = rr, |
| .ifindex = ifindex, |
| }; |
| |
| exist = set_get(a->set_items, &tmp); |
| if (exist) { |
| /* 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) != (exist->rr->ttl == 0)) |
| return -EINVAL; |
| |
| /* Entry already exists, keep the entry with the higher TTL. */ |
| if (rr->ttl > exist->rr->ttl) { |
| dns_resource_record_unref(exist->rr); |
| exist->rr = dns_resource_record_ref(rr); |
| |
| /* Update RRSIG and RR at the same time */ |
| if (rrsig) { |
| dns_resource_record_ref(rrsig); |
| dns_resource_record_unref(exist->rrsig); |
| exist->rrsig = rrsig; |
| } |
| } |
| |
| exist->flags |= flags; |
| return 0; |
| } |
| |
| return dns_answer_add_raw(a, rr, ifindex, flags, rrsig); |
| } |
| |
| static int dns_answer_add_all(DnsAnswer *a, DnsAnswer *b) { |
| DnsAnswerItem *item; |
| int r; |
| |
| DNS_ANSWER_FOREACH_ITEM(item, b) { |
| r = dns_answer_add(a, item->rr, item->ifindex, item->flags, item->rrsig); |
| if (r < 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| int dns_answer_add_extend( |
| DnsAnswer **a, |
| DnsResourceRecord *rr, |
| int ifindex, |
| DnsAnswerFlags flags, |
| DnsResourceRecord *rrsig) { |
| |
| 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, rrsig); |
| } |
| |
| 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 = strjoin("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, NULL); |
| } |
| |
| 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; |
| } |
| |
| bool 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; |
| } |
| |
| bool dns_answer_contains(DnsAnswer *answer, DnsResourceRecord *rr) { |
| DnsResourceRecord *i; |
| |
| DNS_ANSWER_FOREACH(i, answer) |
| if (dns_resource_record_equal(i, rr)) |
| return true; |
| |
| return false; |
| } |
| |
| int dns_answer_find_soa( |
| DnsAnswer *a, |
| const DnsResourceKey *key, |
| DnsResourceRecord **ret, |
| DnsAnswerFlags *ret_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) |
| goto not_found; |
| |
| 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) |
| goto not_found; |
| |
| if (ret) |
| *ret = soa; |
| if (ret_flags) |
| *ret_flags = soa_flags; |
| |
| return 1; |
| |
| not_found: |
| if (ret) |
| *ret = NULL; |
| if (ret_flags) |
| *ret_flags = 0; |
| |
| return 0; |
| } |
| |
| int dns_answer_find_cname_or_dname( |
| DnsAnswer *a, |
| const DnsResourceKey *key, |
| DnsResourceRecord **ret, |
| DnsAnswerFlags *ret_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 (ret_flags) |
| *ret_flags = rr_flags; |
| return 1; |
| } |
| } |
| |
| if (ret) |
| *ret = NULL; |
| if (ret_flags) |
| *ret_flags = 0; |
| |
| return 0; |
| } |
| |
| int dns_answer_merge(DnsAnswer *a, DnsAnswer *b, DnsAnswer **ret) { |
| _cleanup_(dns_answer_unrefp) DnsAnswer *k = NULL; |
| int r; |
| |
| assert(ret); |
| |
| if (a == b) { |
| *ret = dns_answer_ref(a); |
| return 0; |
| } |
| |
| 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; |
| DnsAnswerItem *item; |
| |
| copy = dns_answer_new((*a)->n_rrs); |
| if (!copy) |
| return -ENOMEM; |
| |
| DNS_ANSWER_FOREACH_ITEM(item, *a) { |
| r = dns_resource_key_equal(item->rr->key, key); |
| if (r < 0) |
| return r; |
| if (r > 0) |
| continue; |
| |
| r = dns_answer_add_raw(copy, item->rr, item->ifindex, item->flags, item->rrsig); |
| 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); |
| dns_resource_record_unref((*a)->items[i].rrsig); |
| |
| 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; |
| DnsAnswerItem *item; |
| |
| copy = dns_answer_new((*a)->n_rrs); |
| if (!copy) |
| return -ENOMEM; |
| |
| DNS_ANSWER_FOREACH_ITEM(item, *a) { |
| r = dns_resource_record_equal(item->rr, rm); |
| if (r < 0) |
| return r; |
| if (r > 0) |
| continue; |
| |
| r = dns_answer_add_raw(copy, item->rr, item->ifindex, item->flags, item->rrsig); |
| 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); |
| dns_resource_record_unref((*a)->items[i].rrsig); |
| 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_answer_keys(DnsAnswer **a, DnsAnswer *b) { |
| _cleanup_(dns_resource_key_unrefp) DnsResourceKey *prev = NULL; |
| DnsAnswerItem *item; |
| int r; |
| |
| /* Removes all items from '*a' that have a matching key in 'b' */ |
| |
| DNS_ANSWER_FOREACH_ITEM(item, b) { |
| |
| if (prev && dns_resource_key_equal(item->rr->key, prev)) /* Skip this one, we already looked at it */ |
| continue; |
| |
| r = dns_answer_remove_by_key(a, item->rr->key); |
| if (r < 0) |
| return r; |
| |
| /* Let's remember this entry's RR key, to optimize the loop a bit: if we have an RRset with |
| * more than one item then we don't need to remove the key multiple times */ |
| dns_resource_key_unref(prev); |
| prev = dns_resource_key_ref(item->rr->key); |
| } |
| |
| return 0; |
| } |
| |
| int dns_answer_copy_by_key( |
| DnsAnswer **a, |
| DnsAnswer *source, |
| const DnsResourceKey *key, |
| DnsAnswerFlags or_flags, |
| DnsResourceRecord *rrsig) { |
| |
| DnsAnswerItem *item; |
| int r; |
| |
| assert(a); |
| assert(key); |
| |
| /* Copy all RRs matching the specified key from source into *a */ |
| |
| DNS_ANSWER_FOREACH_ITEM(item, source) { |
| |
| r = dns_resource_key_equal(item->rr->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, item->rr, item->ifindex, item->flags|or_flags, rrsig ?: item->rrsig); |
| if (r < 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| int dns_answer_move_by_key( |
| DnsAnswer **to, |
| DnsAnswer **from, |
| const DnsResourceKey *key, |
| DnsAnswerFlags or_flags, |
| DnsResourceRecord *rrsig) { |
| int r; |
| |
| assert(to); |
| assert(from); |
| assert(key); |
| |
| r = dns_answer_copy_by_key(to, *from, key, or_flags, rrsig); |
| 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 (dns_resource_record_is_link_local_address(a->items[i].rr) != 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; |
| int r; |
| |
| if ((*a)->n_ref > 1) |
| return -EBUSY; |
| |
| ns = (*a)->n_rrs; |
| assert(ns <= UINT16_MAX); /* Maximum number of RRs we can stick into a DNS packet section */ |
| |
| if (n_free > UINT16_MAX - ns) /* overflow check */ |
| ns = UINT16_MAX; |
| else |
| ns += n_free; |
| |
| if ((*a)->n_allocated >= ns) |
| return 0; |
| |
| /* Allocate more than we need, but not more than UINT16_MAX */ |
| if (ns <= UINT16_MAX/2) |
| ns *= 2; |
| else |
| ns = UINT16_MAX; |
| |
| /* This must be done before realloc() below. Otherwise, the original DnsAnswer object |
| * may be broken. */ |
| r = set_reserve((*a)->set_items, ns); |
| if (r < 0) |
| return r; |
| |
| n = realloc(*a, offsetof(DnsAnswer, items) + sizeof(DnsAnswerItem) * ns); |
| if (!n) |
| return -ENOMEM; |
| |
| n->n_allocated = ns; |
| |
| /* Previously all items are stored in the set, and the enough memory area is allocated |
| * in the above. So set_put() in the below cannot fail. */ |
| set_clear(n->set_items); |
| for (size_t i = 0; i < n->n_rrs; i++) |
| assert_se(set_put(n->set_items, &n->items[i]) > 0); |
| } 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) { |
| 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. */ |
| |
| if (*a && (*a)->n_ref > 1) { |
| _cleanup_(dns_answer_unrefp) DnsAnswer *n = NULL; |
| size_t ns; |
| |
| ns = (*a)->n_rrs; |
| assert(ns <= UINT16_MAX); /* Maximum number of RRs we can stick into a DNS packet section */ |
| |
| if (n_free > UINT16_MAX - ns) /* overflow check */ |
| ns = UINT16_MAX; |
| else if (n_free > 0) { /* Increase size and double the result, just in case — except if the |
| * increase is specified as 0, in which case we just allocate the |
| * exact amount as before, under the assumption this is just a request |
| * to copy the answer. */ |
| ns += n_free; |
| |
| if (ns <= UINT16_MAX/2) /* overflow check */ |
| ns *= 2; |
| else |
| ns = UINT16_MAX; |
| } |
| |
| n = dns_answer_new(ns); |
| if (!n) |
| return -ENOMEM; |
| |
| r = dns_answer_add_raw_all(n, *a); |
| if (r < 0) |
| return r; |
| |
| dns_answer_unref(*a); |
| assert_se(*a = TAKE_PTR(n)); |
| } else if (n_free > 0) { |
| r = dns_answer_reserve(a, n_free); |
| if (r < 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * This function is not used in the code base, but is useful when debugging. Do not delete. |
| */ |
| void dns_answer_dump(DnsAnswer *answer, FILE *f) { |
| DnsAnswerItem *item; |
| |
| if (!f) |
| f = stdout; |
| |
| DNS_ANSWER_FOREACH_ITEM(item, answer) { |
| const char *t; |
| |
| fputc('\t', f); |
| |
| t = dns_resource_record_to_string(item->rr); |
| if (!t) { |
| log_oom(); |
| continue; |
| } |
| |
| fputs(t, f); |
| fputs("\t;", f); |
| fprintf(f, " ttl=%" PRIu32, item->rr->ttl); |
| |
| if (item->ifindex != 0) |
| fprintf(f, " ifindex=%i", item->ifindex); |
| if (item->rrsig) |
| fputs(" rrsig", f); |
| if (item->flags & DNS_ANSWER_AUTHENTICATED) |
| fputs(" authenticated", f); |
| if (item->flags & DNS_ANSWER_CACHEABLE) |
| fputs(" cacheable", f); |
| if (item->flags & DNS_ANSWER_SHARED_OWNER) |
| fputs(" shared-owner", f); |
| if (item->flags & DNS_ANSWER_CACHE_FLUSH) |
| fputs(" cache-flush", f); |
| if (item->flags & DNS_ANSWER_GOODBYE) |
| fputs(" goodbye", f); |
| if (item->flags & DNS_ANSWER_SECTION_ANSWER) |
| fputs(" section-answer", f); |
| if (item->flags & DNS_ANSWER_SECTION_AUTHORITY) |
| fputs(" section-authority", f); |
| if (item->flags & DNS_ANSWER_SECTION_ADDITIONAL) |
| fputs(" section-additional", 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; |
| } |
| |
| void dns_answer_randomize(DnsAnswer *a) { |
| size_t n; |
| |
| /* Permutes the answer list randomly (Knuth shuffle) */ |
| |
| n = dns_answer_size(a); |
| if (n <= 1) |
| return; |
| |
| for (size_t i = 0; i < n; i++) { |
| size_t k; |
| |
| k = random_u64_range(n); |
| if (k == i) |
| continue; |
| |
| SWAP_TWO(a->items[i], a->items[k]); |
| } |
| } |
| |
| uint32_t dns_answer_min_ttl(DnsAnswer *a) { |
| uint32_t ttl = UINT32_MAX; |
| DnsResourceRecord *rr; |
| |
| /* Return the smallest TTL of all RRs in this answer */ |
| |
| DNS_ANSWER_FOREACH(rr, a) { |
| /* Don't consider OPT (where the TTL field is used for other purposes than an actual TTL) */ |
| |
| if (dns_type_is_pseudo(rr->key->type) || |
| dns_class_is_pseudo(rr->key->class)) |
| continue; |
| |
| ttl = MIN(ttl, rr->ttl); |
| } |
| |
| return ttl; |
| } |
