src/resolve/resolved-dns-answer.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 /***
   5   This file is part of systemd.
   6
   7   Copyright 2014 Lennart Poettering
   8 ***/
   9
  10 typedef struct DnsAnswer DnsAnswer;
  11 typedef struct DnsAnswerItem DnsAnswerItem;
  12
  13 #include "macro.h"
  14 #include "resolved-dns-rr.h"
  15
  16 /* A simple array of resource records. We keep track of the
  17  * originating ifindex for each RR where that makes sense, so that we
  18  * can qualify A and AAAA RRs referring to a local link with the
  19  * right ifindex.
  20  *
  21  * Note that we usually encode the empty DnsAnswer object as a simple NULL. */
  22
  23 typedef enum DnsAnswerFlags {
  24         DNS_ANSWER_AUTHENTICATED = 1,  /* Item has been authenticated */
  25         DNS_ANSWER_CACHEABLE     = 2,  /* Item is subject to caching */
  26         DNS_ANSWER_SHARED_OWNER  = 4,  /* For mDNS: RRset may be owner by multiple peers */
  27         DNS_ANSWER_CACHE_FLUSH   = 8,  /* For mDNS: sets cache-flush bit in the rrclass of response records */
  28         DNS_ANSWER_GOODBYE       = 16, /* For mDNS: item is subject to disappear */
  29 } DnsAnswerFlags;
  30
  31 struct DnsAnswerItem {
  32         DnsResourceRecord *rr;
  33         int ifindex;
  34         DnsAnswerFlags flags;
  35 };
  36
  37 struct DnsAnswer {
  38         unsigned n_ref;
  39         unsigned n_rrs, n_allocated;
  40         DnsAnswerItem items[0];
  41 };
  42
  43 DnsAnswer *dns_answer_new(unsigned n);
  44 DnsAnswer *dns_answer_ref(DnsAnswer *a);
  45 DnsAnswer *dns_answer_unref(DnsAnswer *a);
  46
  47 int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags);
  48 int dns_answer_add_extend(DnsAnswer **a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags);
  49 int dns_answer_add_soa(DnsAnswer *a, const char *name, uint32_t ttl, int ifindex);
  50
  51 int dns_answer_match_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *combined_flags);
  52 int dns_answer_contains_rr(DnsAnswer *a, DnsResourceRecord *rr, DnsAnswerFlags *combined_flags);
  53 int dns_answer_contains_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
  57 int dns_answer_find_soa(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags);
  58 int dns_answer_find_cname_or_dname(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags);
  59
  60 int dns_answer_merge(DnsAnswer *a, DnsAnswer *b, DnsAnswer **ret);
  61 int dns_answer_extend(DnsAnswer **a, DnsAnswer *b);
  62
  63 void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local);
  64
  65 int dns_answer_reserve(DnsAnswer **a, unsigned n_free);
  66 int dns_answer_reserve_or_clone(DnsAnswer **a, unsigned n_free);
  67
  68 int dns_answer_remove_by_key(DnsAnswer **a, const DnsResourceKey *key);
  69 int dns_answer_remove_by_rr(DnsAnswer **a, DnsResourceRecord *rr);
  70
  71 int dns_answer_copy_by_key(DnsAnswer **a, DnsAnswer *source, const DnsResourceKey *key, DnsAnswerFlags or_flags);
  72 int dns_answer_move_by_key(DnsAnswer **to, DnsAnswer **from, const DnsResourceKey *key, DnsAnswerFlags or_flags);
  73
  74 bool dns_answer_has_dname_for_cname(DnsAnswer *a, DnsResourceRecord *cname);
  75
  76 static inline unsigned dns_answer_size(DnsAnswer *a) {
  77         return a ? a->n_rrs : 0;
  78 }
  79
  80 static inline bool dns_answer_isempty(DnsAnswer *a) {
  81         return dns_answer_size(a) <= 0;
  82 }
  83
  84 void dns_answer_dump(DnsAnswer *answer, FILE *f);
  85
  86 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsAnswer*, dns_answer_unref);
  87
  88 #define _DNS_ANSWER_FOREACH(q, kk, a)                                   \
  89         for (unsigned UNIQ_T(i, q) = ({                                 \
  90                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
  91                                 0;                                      \
  92                         });                                             \
  93              (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
  94              UNIQ_T(i, q)++, (kk) = (UNIQ_T(i, q) < (a)->n_rrs ? (a)->items[UNIQ_T(i, q)].rr : NULL))
  95
  96 #define DNS_ANSWER_FOREACH(kk, a) _DNS_ANSWER_FOREACH(UNIQ, kk, a)
  97
  98 #define _DNS_ANSWER_FOREACH_IFINDEX(q, kk, ifi, a)                      \
  99         for (unsigned UNIQ_T(i, q) = ({                                 \
 100                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
 101                                 (ifi) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].ifindex : 0; \
 102                                 0;                                      \
 103                         });                                             \
 104              (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
 105              UNIQ_T(i, q)++,                                            \
 106                      (kk) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].rr : NULL), \
 107                      (ifi) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].ifindex : 0))
 108
 109 #define DNS_ANSWER_FOREACH_IFINDEX(kk, ifindex, a) _DNS_ANSWER_FOREACH_IFINDEX(UNIQ, kk, ifindex, a)
 110
 111 #define _DNS_ANSWER_FOREACH_FLAGS(q, kk, fl, a)                         \
 112         for (unsigned UNIQ_T(i, q) = ({                                 \
 113                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
 114                                 (fl) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].flags : 0; \
 115                                 0;                                      \
 116                         });                                             \
 117              (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
 118              UNIQ_T(i, q)++,                                            \
 119                      (kk) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].rr : NULL), \
 120                      (fl) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].flags : 0))
 121
 122 #define DNS_ANSWER_FOREACH_FLAGS(kk, flags, a) _DNS_ANSWER_FOREACH_FLAGS(UNIQ, kk, flags, a)
 123
 124 #define _DNS_ANSWER_FOREACH_FULL(q, kk, ifi, fl, a)                     \
 125         for (unsigned UNIQ_T(i, q) = ({                                 \
 126                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
 127                                 (ifi) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].ifindex : 0; \
 128                                 (fl) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].flags : 0; \
 129                                 0;                                      \
 130                         });                                             \
 131              (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
 132              UNIQ_T(i, q)++,                                            \
 133                      (kk) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].rr : NULL), \
 134                      (ifi) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].ifindex : 0), \
 135                      (fl) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].flags : 0))
 136
 137 #define DNS_ANSWER_FOREACH_FULL(kk, ifindex, flags, a) _DNS_ANSWER_FOREACH_FULL(UNIQ, kk, ifindex, flags, a)