src/resolve/resolved-dns-answer.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 /***
   5   Copyright 2014 Lennart Poettering
   6 ***/
   7
   8 typedef struct DnsAnswer DnsAnswer;
   9 typedef struct DnsAnswerItem DnsAnswerItem;
  10
  11 #include "macro.h"
  12 #include "resolved-dns-rr.h"
  13
  14 /* A simple array of resource records. We keep track of the
  15  * originating ifindex for each RR where that makes sense, so that we
  16  * can qualify A and AAAA RRs referring to a local link with the
  17  * right ifindex.
  18  *
  19  * Note that we usually encode the empty DnsAnswer object as a simple NULL. */
  20
  21 typedef enum DnsAnswerFlags {
  22         DNS_ANSWER_AUTHENTICATED = 1,  /* Item has been authenticated */
  23         DNS_ANSWER_CACHEABLE     = 2,  /* Item is subject to caching */
  24         DNS_ANSWER_SHARED_OWNER  = 4,  /* For mDNS: RRset may be owner by multiple peers */
  25         DNS_ANSWER_CACHE_FLUSH   = 8,  /* For mDNS: sets cache-flush bit in the rrclass of response records */
  26         DNS_ANSWER_GOODBYE       = 16, /* For mDNS: item is subject to disappear */
  27 } DnsAnswerFlags;
  28
  29 struct DnsAnswerItem {
  30         DnsResourceRecord *rr;
  31         int ifindex;
  32         DnsAnswerFlags flags;
  33 };
  34
  35 struct DnsAnswer {
  36         unsigned n_ref;
  37         size_t n_rrs, n_allocated;
  38         DnsAnswerItem items[0];
  39 };
  40
  41 DnsAnswer *dns_answer_new(size_t n);
  42 DnsAnswer *dns_answer_ref(DnsAnswer *a);
  43 DnsAnswer *dns_answer_unref(DnsAnswer *a);
  44
  45 int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags);
  46 int dns_answer_add_extend(DnsAnswer **a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags);
  47 int dns_answer_add_soa(DnsAnswer *a, const char *name, uint32_t ttl, int ifindex);
  48
  49 int dns_answer_match_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *combined_flags);
  50 int dns_answer_contains_rr(DnsAnswer *a, DnsResourceRecord *rr, DnsAnswerFlags *combined_flags);
  51 int dns_answer_contains_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *combined_flags);
  52 int dns_answer_contains_nsec_or_nsec3(DnsAnswer *a);
  53 int dns_answer_contains_zone_nsec3(DnsAnswer *answer, const char *zone);
  54
  55 int dns_answer_find_soa(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags);
  56 int dns_answer_find_cname_or_dname(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags);
  57
  58 int dns_answer_merge(DnsAnswer *a, DnsAnswer *b, DnsAnswer **ret);
  59 int dns_answer_extend(DnsAnswer **a, DnsAnswer *b);
  60
  61 void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local);
  62
  63 int dns_answer_reserve(DnsAnswer **a, size_t n_free);
  64 int dns_answer_reserve_or_clone(DnsAnswer **a, size_t n_free);
  65
  66 int dns_answer_remove_by_key(DnsAnswer **a, const DnsResourceKey *key);
  67 int dns_answer_remove_by_rr(DnsAnswer **a, DnsResourceRecord *rr);
  68
  69 int dns_answer_copy_by_key(DnsAnswer **a, DnsAnswer *source, const DnsResourceKey *key, DnsAnswerFlags or_flags);
  70 int dns_answer_move_by_key(DnsAnswer **to, DnsAnswer **from, const DnsResourceKey *key, DnsAnswerFlags or_flags);
  71
  72 bool dns_answer_has_dname_for_cname(DnsAnswer *a, DnsResourceRecord *cname);
  73
  74 static inline size_t dns_answer_size(DnsAnswer *a) {
  75         return a ? a->n_rrs : 0;
  76 }
  77
  78 static inline bool dns_answer_isempty(DnsAnswer *a) {
  79         return dns_answer_size(a) <= 0;
  80 }
  81
  82 void dns_answer_dump(DnsAnswer *answer, FILE *f);
  83
  84 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsAnswer*, dns_answer_unref);
  85
  86 #define _DNS_ANSWER_FOREACH(q, kk, a)                                   \
  87         for (size_t UNIQ_T(i, q) = ({                                   \
  88                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
  89                                 0;                                      \
  90                         });                                             \
  91              (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
  92              UNIQ_T(i, q)++, (kk) = (UNIQ_T(i, q) < (a)->n_rrs ? (a)->items[UNIQ_T(i, q)].rr : NULL))
  93
  94 #define DNS_ANSWER_FOREACH(kk, a) _DNS_ANSWER_FOREACH(UNIQ, kk, a)
  95
  96 #define _DNS_ANSWER_FOREACH_IFINDEX(q, kk, ifi, a)                      \
  97         for (size_t UNIQ_T(i, q) = ({                                   \
  98                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
  99                                 (ifi) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].ifindex : 0; \
 100                                 0;                                      \
 101                         });                                             \
 102              (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
 103              UNIQ_T(i, q)++,                                            \
 104                      (kk) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].rr : NULL), \
 105                      (ifi) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].ifindex : 0))
 106
 107 #define DNS_ANSWER_FOREACH_IFINDEX(kk, ifindex, a) _DNS_ANSWER_FOREACH_IFINDEX(UNIQ, kk, ifindex, a)
 108
 109 #define _DNS_ANSWER_FOREACH_FLAGS(q, kk, fl, a)                         \
 110         for (size_t UNIQ_T(i, q) = ({                                   \
 111                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
 112                                 (fl) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].flags : 0; \
 113                                 0;                                      \
 114                         });                                             \
 115              (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
 116              UNIQ_T(i, q)++,                                            \
 117                      (kk) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].rr : NULL), \
 118                      (fl) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].flags : 0))
 119
 120 #define DNS_ANSWER_FOREACH_FLAGS(kk, flags, a) _DNS_ANSWER_FOREACH_FLAGS(UNIQ, kk, flags, a)
 121
 122 #define _DNS_ANSWER_FOREACH_FULL(q, kk, ifi, fl, a)                     \
 123         for (size_t UNIQ_T(i, q) = ({                                   \
 124                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
 125                                 (ifi) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].ifindex : 0; \
 126                                 (fl) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].flags : 0; \
 127                                 0;                                      \
 128                         });                                             \
 129              (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
 130              UNIQ_T(i, q)++,                                            \
 131                      (kk) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].rr : NULL), \
 132                      (ifi) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].ifindex : 0), \
 133                      (fl) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].flags : 0))
 134
 135 #define DNS_ANSWER_FOREACH_FULL(kk, ifindex, flags, a) _DNS_ANSWER_FOREACH_FULL(UNIQ, kk, ifindex, flags, a)