src/resolve/resolved-dns-answer.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 #pragma once
   3
   4 typedef struct DnsAnswer DnsAnswer;
   5 typedef struct DnsAnswerItem DnsAnswerItem;
   6
   7 #include "macro.h"
   8 #include "ordered-set.h"
   9 #include "resolved-dns-rr.h"
  10
  11 /* A simple array of resource records. We keep track of the originating ifindex for each RR where that makes
  12  * sense, so that we can qualify A and AAAA RRs referring to a local link with the right ifindex.
  13  *
  14  * Note that we usually encode the empty DnsAnswer object as a simple NULL. */
  15
  16 typedef enum DnsAnswerFlags {
  17         DNS_ANSWER_AUTHENTICATED       = 1 << 0, /* Item has been authenticated */
  18         DNS_ANSWER_CACHEABLE           = 1 << 1, /* Item is subject to caching */
  19         DNS_ANSWER_SHARED_OWNER        = 1 << 2, /* For mDNS: RRset may be owner by multiple peers */
  20         DNS_ANSWER_CACHE_FLUSH         = 1 << 3, /* For mDNS: sets cache-flush bit in the rrclass of response records */
  21         DNS_ANSWER_GOODBYE             = 1 << 4, /* For mDNS: item is subject to disappear */
  22         DNS_ANSWER_SECTION_ANSWER      = 1 << 5, /* When parsing: RR originates from answer section */
  23         DNS_ANSWER_SECTION_AUTHORITY   = 1 << 6, /* When parsing: RR originates from authority section */
  24         DNS_ANSWER_SECTION_ADDITIONAL  = 1 << 7, /* When parsing: RR originates from additional section */
  25         DNS_ANSWER_REFUSE_TTL_NO_MATCH = 1 << 8, /* For mDNS; refuse to merge a zero TTL RR with a nonzero TTL RR */
  26
  27         DNS_ANSWER_MASK_SECTIONS      = DNS_ANSWER_SECTION_ANSWER|
  28                                         DNS_ANSWER_SECTION_AUTHORITY|
  29                                         DNS_ANSWER_SECTION_ADDITIONAL,
  30 } DnsAnswerFlags;
  31
  32 struct DnsAnswerItem {
  33         unsigned n_ref;
  34         DnsResourceRecord *rr;
  35         DnsResourceRecord *rrsig; /* Optionally, also store RRSIG RR that successfully validates this item */
  36         int ifindex;
  37         DnsAnswerFlags flags;
  38 };
  39
  40 struct DnsAnswer {
  41         unsigned n_ref;
  42         OrderedSet *items;
  43 };
  44
  45 DnsAnswer *dns_answer_new(size_t n);
  46 DnsAnswer *dns_answer_ref(DnsAnswer *a);
  47 DnsAnswer *dns_answer_unref(DnsAnswer *a);
  48
  49 #define DNS_ANSWER_REPLACE(a, b)                \
  50         do {                                    \
  51                 typeof(a)* _a = &(a);           \
  52                 typeof(b) _b = (b);             \
  53                 dns_answer_unref(*_a);          \
  54                 *_a = _b;                       \
  55         } while(0)
  56
  57 int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags, DnsResourceRecord *rrsig);
  58 int dns_answer_add_extend(DnsAnswer **a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags, DnsResourceRecord *rrsig);
  59 int dns_answer_add_soa(DnsAnswer *a, const char *name, uint32_t ttl, int ifindex);
  60
  61 int dns_answer_match_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *ret_flags);
  62 bool dns_answer_contains_nsec_or_nsec3(DnsAnswer *a);
  63 int dns_answer_contains_zone_nsec3(DnsAnswer *answer, const char *zone);
  64 bool dns_answer_contains(DnsAnswer *answer, DnsResourceRecord *rr);
  65
  66 int dns_answer_find_soa(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *ret_flags);
  67 int dns_answer_find_cname_or_dname(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *ret_flags);
  68
  69 int dns_answer_merge(DnsAnswer *a, DnsAnswer *b, DnsAnswer **ret);
  70 int dns_answer_extend(DnsAnswer **a, DnsAnswer *b);
  71
  72 void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local);
  73
  74 int dns_answer_reserve(DnsAnswer **a, size_t n_free);
  75 int dns_answer_reserve_or_clone(DnsAnswer **a, size_t n_free);
  76
  77 int dns_answer_remove_by_key(DnsAnswer **a, const DnsResourceKey *key);
  78 int dns_answer_remove_by_rr(DnsAnswer **a, DnsResourceRecord *rr);
  79 int dns_answer_remove_by_answer_keys(DnsAnswer **a, DnsAnswer *b);
  80
  81 int dns_answer_copy_by_key(DnsAnswer **a, DnsAnswer *source, const DnsResourceKey *key, DnsAnswerFlags or_flags, DnsResourceRecord *rrsig);
  82 int dns_answer_move_by_key(DnsAnswer **to, DnsAnswer **from, const DnsResourceKey *key, DnsAnswerFlags or_flags, DnsResourceRecord *rrsig);
  83
  84 int dns_answer_has_dname_for_cname(DnsAnswer *a, DnsResourceRecord *cname);
  85
  86 static inline size_t dns_answer_size(DnsAnswer *a) {
  87         return a ? ordered_set_size(a->items) : 0;
  88 }
  89
  90 static inline bool dns_answer_isempty(DnsAnswer *a) {
  91         return dns_answer_size(a) <= 0;
  92 }
  93
  94 void dns_answer_dump(DnsAnswer *answer, FILE *f);
  95
  96 void dns_answer_randomize(DnsAnswer *a);
  97
  98 uint32_t dns_answer_min_ttl(DnsAnswer *a);
  99
 100 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsAnswer*, dns_answer_unref);
 101
 102 typedef struct DnsAnswerIterator {
 103         Iterator iterator;
 104         DnsAnswer *answer;
 105         DnsAnswerItem *item;
 106 } DnsAnswerIterator;
 107
 108 #define _DNS_ANSWER_FOREACH(kk, a, i)                                   \
 109         for (DnsAnswerIterator i = { .iterator = ITERATOR_FIRST, .answer = (a) };  \
 110              i.answer &&                                                \
 111              ordered_set_iterate(i.answer->items, &i.iterator, (void**) &(i.item)) && \
 112              (kk = i.item->rr, true); )
 113
 114 #define DNS_ANSWER_FOREACH(rr, a) _DNS_ANSWER_FOREACH(rr, a, UNIQ_T(i, UNIQ))
 115
 116 #define _DNS_ANSWER_FOREACH_IFINDEX(kk, ifi, a, i)                      \
 117         for (DnsAnswerIterator i = { .iterator = ITERATOR_FIRST, .answer = (a) };  \
 118              i.answer &&                                                \
 119              ordered_set_iterate(i.answer->items, &i.iterator, (void**) &(i.item)) && \
 120              (kk = i.item->rr, ifi = i.item->ifindex, true); )
 121
 122 #define DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, a) _DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, a, UNIQ_T(i, UNIQ))
 123
 124 #define _DNS_ANSWER_FOREACH_FLAGS(kk, fl, a, i)                         \
 125         for (DnsAnswerIterator i = { .iterator = ITERATOR_FIRST, .answer = (a) };  \
 126              i.answer &&                                                \
 127              ordered_set_iterate(i.answer->items, &i.iterator, (void**) &(i.item)) && \
 128              (kk = i.item->rr, fl = i.item->flags, true); )
 129
 130 #define DNS_ANSWER_FOREACH_FLAGS(rr, flags, a) _DNS_ANSWER_FOREACH_FLAGS(rr, flags, a, UNIQ_T(i, UNIQ))
 131
 132 #define _DNS_ANSWER_FOREACH_ITEM(it, a, i)                            \
 133         for (DnsAnswerIterator i = { .iterator = ITERATOR_FIRST, .answer = (a) };  \
 134              i.answer &&                                                \
 135              ordered_set_iterate(i.answer->items, &i.iterator, (void**) &(i.item)) && \
 136              (it = i.item, true); )
 137
 138 #define DNS_ANSWER_FOREACH_ITEM(item, a) _DNS_ANSWER_FOREACH_ITEM(item, a, UNIQ_T(i, UNIQ))