1 files changed, 138 insertions, 0 deletions
diff --git a/src/resolve/resolved-dns-answer.h b/src/resolve/resolved-dns-answer.h
new file mode 100644
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--- /dev/null
+++ b/src/resolve/resolved-dns-answer.h
@@ -0,0 +1,138 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+typedef struct DnsAnswer DnsAnswer;
+typedef struct DnsAnswerItem DnsAnswerItem;
+
+#include "macro.h"
+#include "ordered-set.h"
+#include "resolved-dns-rr.h"
+
+/* A simple array of resource records. We keep track of the originating ifindex for each RR where that makes
+ * sense, so that we can qualify A and AAAA RRs referring to a local link with the right ifindex.
+ *
+ * Note that we usually encode the empty DnsAnswer object as a simple NULL. */
+
+typedef enum DnsAnswerFlags {
+        DNS_ANSWER_AUTHENTICATED       = 1 << 0, /* Item has been authenticated */
+        DNS_ANSWER_CACHEABLE           = 1 << 1, /* Item is subject to caching */
+        DNS_ANSWER_SHARED_OWNER        = 1 << 2, /* For mDNS: RRset may be owner by multiple peers */
+        DNS_ANSWER_CACHE_FLUSH         = 1 << 3, /* For mDNS: sets cache-flush bit in the rrclass of response records */
+        DNS_ANSWER_GOODBYE             = 1 << 4, /* For mDNS: item is subject to disappear */
+        DNS_ANSWER_SECTION_ANSWER      = 1 << 5, /* When parsing: RR originates from answer section */
+        DNS_ANSWER_SECTION_AUTHORITY   = 1 << 6, /* When parsing: RR originates from authority section */
+        DNS_ANSWER_SECTION_ADDITIONAL  = 1 << 7, /* When parsing: RR originates from additional section */
+        DNS_ANSWER_REFUSE_TTL_NO_MATCH = 1 << 8, /* For mDNS; refuse to merge a zero TTL RR with a nonzero TTL RR */
+
+        DNS_ANSWER_MASK_SECTIONS      = DNS_ANSWER_SECTION_ANSWER|
+                                        DNS_ANSWER_SECTION_AUTHORITY|
+                                        DNS_ANSWER_SECTION_ADDITIONAL,
+} DnsAnswerFlags;
+
+struct DnsAnswerItem {
+        unsigned n_ref;
+        DnsResourceRecord *rr;
+        DnsResourceRecord *rrsig; /* Optionally, also store RRSIG RR that successfully validates this item */
+        int ifindex;
+        DnsAnswerFlags flags;
+};
+
+struct DnsAnswer {
+        unsigned n_ref;
+        OrderedSet *items;
+};
+
+DnsAnswer *dns_answer_new(size_t n);
+DnsAnswer *dns_answer_ref(DnsAnswer *a);
+DnsAnswer *dns_answer_unref(DnsAnswer *a);
+
+#define DNS_ANSWER_REPLACE(a, b)                \
+        do {                                    \
+                typeof(a)* _a = &(a);           \
+                typeof(b) _b = (b);             \
+                dns_answer_unref(*_a);          \
+                *_a = _b;                       \
+        } while(0)
+
+int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags, DnsResourceRecord *rrsig);
+int dns_answer_add_extend(DnsAnswer **a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags, DnsResourceRecord *rrsig);
+int dns_answer_add_soa(DnsAnswer *a, const char *name, uint32_t ttl, int ifindex);
+
+int dns_answer_match_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *ret_flags);
+bool dns_answer_contains_nsec_or_nsec3(DnsAnswer *a);
+int dns_answer_contains_zone_nsec3(DnsAnswer *answer, const char *zone);
+bool dns_answer_contains(DnsAnswer *answer, DnsResourceRecord *rr);
+
+int dns_answer_find_soa(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *ret_flags);
+int dns_answer_find_cname_or_dname(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *ret_flags);
+
+int dns_answer_merge(DnsAnswer *a, DnsAnswer *b, DnsAnswer **ret);
+int dns_answer_extend(DnsAnswer **a, DnsAnswer *b);
+
+void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local);
+
+int dns_answer_reserve(DnsAnswer **a, size_t n_free);
+int dns_answer_reserve_or_clone(DnsAnswer **a, size_t n_free);
+
+int dns_answer_remove_by_key(DnsAnswer **a, const DnsResourceKey *key);
+int dns_answer_remove_by_rr(DnsAnswer **a, DnsResourceRecord *rr);
+int dns_answer_remove_by_answer_keys(DnsAnswer **a, DnsAnswer *b);
+
+int dns_answer_copy_by_key(DnsAnswer **a, DnsAnswer *source, const DnsResourceKey *key, DnsAnswerFlags or_flags, DnsResourceRecord *rrsig);
+int dns_answer_move_by_key(DnsAnswer **to, DnsAnswer **from, const DnsResourceKey *key, DnsAnswerFlags or_flags, DnsResourceRecord *rrsig);
+
+int dns_answer_has_dname_for_cname(DnsAnswer *a, DnsResourceRecord *cname);
+
+static inline size_t dns_answer_size(DnsAnswer *a) {
+        return a ? ordered_set_size(a->items) : 0;
+}
+
+static inline bool dns_answer_isempty(DnsAnswer *a) {
+        return dns_answer_size(a) <= 0;
+}
+
+void dns_answer_dump(DnsAnswer *answer, FILE *f);
+
+void dns_answer_randomize(DnsAnswer *a);
+
+uint32_t dns_answer_min_ttl(DnsAnswer *a);
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(DnsAnswer*, dns_answer_unref);
+
+typedef struct DnsAnswerIterator {
+        Iterator iterator;
+        DnsAnswer *answer;
+        DnsAnswerItem *item;
+} DnsAnswerIterator;
+
+#define _DNS_ANSWER_FOREACH(kk, a, i)                                   \
+        for (DnsAnswerIterator i = { .iterator = ITERATOR_FIRST, .answer = (a) };  \
+             i.answer &&                                                \
+             ordered_set_iterate(i.answer->items, &i.iterator, (void**) &(i.item)) && \
+             (kk = i.item->rr, true); )
+
+#define DNS_ANSWER_FOREACH(rr, a) _DNS_ANSWER_FOREACH(rr, a, UNIQ_T(i, UNIQ))
+
+#define _DNS_ANSWER_FOREACH_IFINDEX(kk, ifi, a, i)                      \
+        for (DnsAnswerIterator i = { .iterator = ITERATOR_FIRST, .answer = (a) };  \
+             i.answer &&                                                \
+             ordered_set_iterate(i.answer->items, &i.iterator, (void**) &(i.item)) && \
+             (kk = i.item->rr, ifi = i.item->ifindex, true); )
+
+#define DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, a) _DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, a, UNIQ_T(i, UNIQ))
+
+#define _DNS_ANSWER_FOREACH_FLAGS(kk, fl, a, i)                         \
+        for (DnsAnswerIterator i = { .iterator = ITERATOR_FIRST, .answer = (a) };  \
+             i.answer &&                                                \
+             ordered_set_iterate(i.answer->items, &i.iterator, (void**) &(i.item)) && \
+             (kk = i.item->rr, fl = i.item->flags, true); )
+
+#define DNS_ANSWER_FOREACH_FLAGS(rr, flags, a) _DNS_ANSWER_FOREACH_FLAGS(rr, flags, a, UNIQ_T(i, UNIQ))
+
+#define _DNS_ANSWER_FOREACH_ITEM(it, a, i)                            \
+        for (DnsAnswerIterator i = { .iterator = ITERATOR_FIRST, .answer = (a) };  \
+             i.answer &&                                                \
+             ordered_set_iterate(i.answer->items, &i.iterator, (void**) &(i.item)) && \
+             (it = i.item, true); )
+
+#define DNS_ANSWER_FOREACH_ITEM(item, a) _DNS_ANSWER_FOREACH_ITEM(item, a, UNIQ_T(i, UNIQ))