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   systemd is free software; you can redistribute it and/or modify it
  10   under the terms of the GNU Lesser General Public License as published by
  11   the Free Software Foundation; either version 2.1 of the License, or
  12   (at your option) any later version.
  13
  14   systemd is distributed in the hope that it will be useful, but
  15   WITHOUT ANY WARRANTY; without even the implied warranty of
  16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17   Lesser General Public License for more details.
  18
  19   You should have received a copy of the GNU Lesser General Public License
  20   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  21 ***/
  22
  23 typedef struct DnsAnswer DnsAnswer;
  24 typedef struct DnsAnswerItem DnsAnswerItem;
  25
  26 #include "macro.h"
  27 #include "resolved-dns-rr.h"
  28
  29 /* A simple array of resource records. We keep track of the
  30  * originating ifindex for each RR where that makes sense, so that we
  31  * can qualify A and AAAA RRs referring to a local link with the
  32  * right ifindex.
  33  *
  34  * Note that we usually encode the empty DnsAnswer object as a simple NULL. */
  35
  36 typedef enum DnsAnswerFlags {
  37         DNS_ANSWER_AUTHENTICATED = 1,  /* Item has been authenticated */
  38         DNS_ANSWER_CACHEABLE     = 2,  /* Item is subject to caching */
  39         DNS_ANSWER_SHARED_OWNER  = 4,  /* For mDNS: RRset may be owner by multiple peers */
  40         DNS_ANSWER_CACHE_FLUSH   = 8,  /* For mDNS: sets cache-flush bit in the rrclass of response records */
  41         DNS_ANSWER_GOODBYE       = 16, /* For mDNS: item is subject to disappear */
  42 } DnsAnswerFlags;
  43
  44 struct DnsAnswerItem {
  45         DnsResourceRecord *rr;
  46         int ifindex;
  47         DnsAnswerFlags flags;
  48 };
  49
  50 struct DnsAnswer {
  51         unsigned n_ref;
  52         unsigned n_rrs, n_allocated;
  53         DnsAnswerItem items[0];
  54 };
  55
  56 DnsAnswer *dns_answer_new(unsigned n);
  57 DnsAnswer *dns_answer_ref(DnsAnswer *a);
  58 DnsAnswer *dns_answer_unref(DnsAnswer *a);
  59
  60 int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags);
  61 int dns_answer_add_extend(DnsAnswer **a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags);
  62 int dns_answer_add_soa(DnsAnswer *a, const char *name, uint32_t ttl, int ifindex);
  63
  64 int dns_answer_match_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *combined_flags);
  65 int dns_answer_contains_rr(DnsAnswer *a, DnsResourceRecord *rr, DnsAnswerFlags *combined_flags);
  66 int dns_answer_contains_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *combined_flags);
  67 int dns_answer_contains_nsec_or_nsec3(DnsAnswer *a);
  68 int dns_answer_contains_zone_nsec3(DnsAnswer *answer, const char *zone);
  69
  70 int dns_answer_find_soa(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags);
  71 int dns_answer_find_cname_or_dname(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags);
  72
  73 int dns_answer_merge(DnsAnswer *a, DnsAnswer *b, DnsAnswer **ret);
  74 int dns_answer_extend(DnsAnswer **a, DnsAnswer *b);
  75
  76 void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local);
  77
  78 int dns_answer_reserve(DnsAnswer **a, unsigned n_free);
  79 int dns_answer_reserve_or_clone(DnsAnswer **a, unsigned n_free);
  80
  81 int dns_answer_remove_by_key(DnsAnswer **a, const DnsResourceKey *key);
  82 int dns_answer_remove_by_rr(DnsAnswer **a, DnsResourceRecord *rr);
  83
  84 int dns_answer_copy_by_key(DnsAnswer **a, DnsAnswer *source, const DnsResourceKey *key, DnsAnswerFlags or_flags);
  85 int dns_answer_move_by_key(DnsAnswer **to, DnsAnswer **from, const DnsResourceKey *key, DnsAnswerFlags or_flags);
  86
  87 bool dns_answer_has_dname_for_cname(DnsAnswer *a, DnsResourceRecord *cname);
  88
  89 static inline unsigned dns_answer_size(DnsAnswer *a) {
  90         return a ? a->n_rrs : 0;
  91 }
  92
  93 static inline bool dns_answer_isempty(DnsAnswer *a) {
  94         return dns_answer_size(a) <= 0;
  95 }
  96
  97 void dns_answer_dump(DnsAnswer *answer, FILE *f);
  98
  99 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsAnswer*, dns_answer_unref);
 100
 101 #define _DNS_ANSWER_FOREACH(q, kk, a)                                   \
 102         for (unsigned UNIQ_T(i, q) = ({                                 \
 103                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
 104                                 0;                                      \
 105                         });                                             \
 106              (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
 107              UNIQ_T(i, q)++, (kk) = (UNIQ_T(i, q) < (a)->n_rrs ? (a)->items[UNIQ_T(i, q)].rr : NULL))
 108
 109 #define DNS_ANSWER_FOREACH(kk, a) _DNS_ANSWER_FOREACH(UNIQ, kk, a)
 110
 111 #define _DNS_ANSWER_FOREACH_IFINDEX(q, kk, ifi, a)                      \
 112         for (unsigned UNIQ_T(i, q) = ({                                 \
 113                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
 114                                 (ifi) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].ifindex : 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                      (ifi) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].ifindex : 0))
 121
 122 #define DNS_ANSWER_FOREACH_IFINDEX(kk, ifindex, a) _DNS_ANSWER_FOREACH_IFINDEX(UNIQ, kk, ifindex, a)
 123
 124 #define _DNS_ANSWER_FOREACH_FLAGS(q, kk, fl, a)                         \
 125         for (unsigned UNIQ_T(i, q) = ({                                 \
 126                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
 127                                 (fl) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].flags : 0; \
 128                                 0;                                      \
 129                         });                                             \
 130              (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
 131              UNIQ_T(i, q)++,                                            \
 132                      (kk) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].rr : NULL), \
 133                      (fl) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].flags : 0))
 134
 135 #define DNS_ANSWER_FOREACH_FLAGS(kk, flags, a) _DNS_ANSWER_FOREACH_FLAGS(UNIQ, kk, flags, a)
 136
 137 #define _DNS_ANSWER_FOREACH_FULL(q, kk, ifi, fl, a)                     \
 138         for (unsigned UNIQ_T(i, q) = ({                                 \
 139                                 (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
 140                                 (ifi) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].ifindex : 0; \
 141                                 (fl) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].flags : 0; \
 142                                 0;                                      \
 143                         });                                             \
 144              (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
 145              UNIQ_T(i, q)++,                                            \
 146                      (kk) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].rr : NULL), \
 147                      (ifi) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].ifindex : 0), \
 148                      (fl) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].flags : 0))
 149
 150 #define DNS_ANSWER_FOREACH_FULL(kk, ifindex, flags, a) _DNS_ANSWER_FOREACH_FULL(UNIQ, kk, ifindex, flags, a)