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 "resolved-dns-rr.h"
   9 #include "set.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
  26         DNS_ANSWER_MASK_SECTIONS      = DNS_ANSWER_SECTION_ANSWER|
  27                                         DNS_ANSWER_SECTION_AUTHORITY|
  28                                         DNS_ANSWER_SECTION_ADDITIONAL,
  29 } DnsAnswerFlags;
  30
  31 struct DnsAnswerItem {
  32         DnsResourceRecord *rr;
  33         DnsResourceRecord *rrsig; /* Optionally, also store RRSIG RR that successfully validates this item */
  34         int ifindex;
  35         DnsAnswerFlags flags;
  36 };
  37
  38 struct DnsAnswer {
  39         unsigned n_ref;
  40         Set *set_items; /* Used by dns_answer_add() for optimization. */
  41         size_t n_rrs, n_allocated;
  42         DnsAnswerItem items[0];
  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 int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags, DnsResourceRecord *rrsig);
  50 int dns_answer_add_extend(DnsAnswer **a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags, DnsResourceRecord *rrsig);
  51 int dns_answer_add_soa(DnsAnswer *a, const char *name, uint32_t ttl, int ifindex);
  52
  53 int dns_answer_match_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *combined_flags);
  54 int dns_answer_contains_nsec_or_nsec3(DnsAnswer *a);
  55 int dns_answer_contains_zone_nsec3(DnsAnswer *answer, const char *zone);
  56 int dns_answer_contains(DnsAnswer *answer, DnsResourceRecord *rr);
  57
  58 int dns_answer_find_soa(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *ret_flags);
  59 int dns_answer_find_cname_or_dname(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *ret_flags);
  60
  61 int dns_answer_merge(DnsAnswer *a, DnsAnswer *b, DnsAnswer **ret);
  62 int dns_answer_extend(DnsAnswer **a, DnsAnswer *b);
  63
  64 void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local);
  65
  66 int dns_answer_reserve(DnsAnswer **a, size_t n_free);
  67 int dns_answer_reserve_or_clone(DnsAnswer **a, size_t n_free);
  68
  69 int dns_answer_remove_by_key(DnsAnswer **a, const DnsResourceKey *key);
  70 int dns_answer_remove_by_rr(DnsAnswer **a, DnsResourceRecord *rr);
  71 int dns_answer_remove_by_answer_keys(DnsAnswer **a, DnsAnswer *b);
  72
  73 int dns_answer_copy_by_key(DnsAnswer **a, DnsAnswer *source, const DnsResourceKey *key, DnsAnswerFlags or_flags, DnsResourceRecord *rrsig);
  74 int dns_answer_move_by_key(DnsAnswer **to, DnsAnswer **from, const DnsResourceKey *key, DnsAnswerFlags or_flags, DnsResourceRecord *rrsig);
  75
  76 int dns_answer_has_dname_for_cname(DnsAnswer *a, DnsResourceRecord *cname);
  77
  78 static inline size_t dns_answer_size(DnsAnswer *a) {
  79         return a ? a->n_rrs : 0;
  80 }
  81
  82 static inline bool dns_answer_isempty(DnsAnswer *a) {
  83         return dns_answer_size(a) <= 0;
  84 }
  85
  86 void dns_answer_dump(DnsAnswer *answer, FILE *f);
  87
  88 void dns_answer_randomize(DnsAnswer *a);
  89
  90 uint32_t dns_answer_min_ttl(DnsAnswer *a);
  91
  92 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsAnswer*, dns_answer_unref);
  93
  94 #define _DNS_ANSWER_FOREACH(q, kk, a)                                   \
  95         for (size_t UNIQ_T(i, q) = ({                                   \
  96                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
  97                                 0;                                      \
  98                         });                                             \
  99              (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
 100              UNIQ_T(i, q)++, (kk) = (UNIQ_T(i, q) < (a)->n_rrs ? (a)->items[UNIQ_T(i, q)].rr : NULL))
 101
 102 #define DNS_ANSWER_FOREACH(kk, a) _DNS_ANSWER_FOREACH(UNIQ, kk, a)
 103
 104 #define _DNS_ANSWER_FOREACH_IFINDEX(q, kk, ifi, a)                      \
 105         for (size_t UNIQ_T(i, q) = ({                                   \
 106                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
 107                                 (ifi) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].ifindex : 0; \
 108                                 0;                                      \
 109                         });                                             \
 110              (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
 111              UNIQ_T(i, q)++,                                            \
 112                      (kk) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].rr : NULL), \
 113                      (ifi) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].ifindex : 0))
 114
 115 #define DNS_ANSWER_FOREACH_IFINDEX(kk, ifindex, a) _DNS_ANSWER_FOREACH_IFINDEX(UNIQ, kk, ifindex, a)
 116
 117 #define _DNS_ANSWER_FOREACH_FLAGS(q, kk, fl, a)                         \
 118         for (size_t UNIQ_T(i, q) = ({                                   \
 119                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
 120                                 (fl) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].flags : 0; \
 121                                 0;                                      \
 122                         });                                             \
 123              (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
 124              UNIQ_T(i, q)++,                                            \
 125                      (kk) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].rr : NULL), \
 126                      (fl) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].flags : 0))
 127
 128 #define DNS_ANSWER_FOREACH_FLAGS(kk, flags, a) _DNS_ANSWER_FOREACH_FLAGS(UNIQ, kk, flags, a)
 129
 130 #define _DNS_ANSWER_FOREACH_ITEM(q, item, a)                            \
 131         for (size_t UNIQ_T(i, q) = ({                                   \
 132                                 (item) = dns_answer_isempty(a) ? NULL : (a)->items; \
 133                                 0;                                      \
 134                         });                                             \
 135              UNIQ_T(i, q) < dns_answer_size(a);                         \
 136              UNIQ_T(i, q)++,                                            \
 137                      (item) = ((UNIQ_T(i, q) < dns_answer_size(a)) ? (a)->items + UNIQ_T(i, q) : NULL))
 138
 139 #define DNS_ANSWER_FOREACH_ITEM(item, a) _DNS_ANSWER_FOREACH_ITEM(UNIQ, item, a)