From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 15 Mar 2021 19:47:28 +0000 (+0100)
Subject: resolved: add new helper dns_answer_min_ttl()
X-Git-Tag: v248-rc4~10^2~11
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1499a0a99a0765b4b1b56f56d6712324e740911f;p=thirdparty%2Fsystemd.git

resolved: add new helper dns_answer_min_ttl()
---

diff --git a/src/resolve/resolved-dns-answer.c b/src/resolve/resolved-dns-answer.c
index a667ab5ede4..5fbff81c255 100644
--- a/src/resolve/resolved-dns-answer.c
+++ b/src/resolve/resolved-dns-answer.c
@@ -963,3 +963,22 @@ void dns_answer_randomize(DnsAnswer *a) {
                 SWAP_TWO(a->items[i], a->items[k]);
         }
 }
+
+uint32_t dns_answer_min_ttl(DnsAnswer *a) {
+        uint32_t ttl = UINT32_MAX;
+        DnsResourceRecord *rr;
+
+        /* Return the smallest TTL of all RRs in this answer */
+
+        DNS_ANSWER_FOREACH(rr, a) {
+                /* Don't consider OPT (where the TTL field is used for other purposes than an actual TTL) */
+
+                if (dns_type_is_pseudo(rr->key->type) ||
+                    dns_class_is_pseudo(rr->key->class))
+                        continue;
+
+                ttl = MIN(ttl, rr->ttl);
+        }
+
+        return ttl;
+}
diff --git a/src/resolve/resolved-dns-answer.h b/src/resolve/resolved-dns-answer.h
index 7d19eee4e2b..447da5d6cc3 100644
--- a/src/resolve/resolved-dns-answer.h
+++ b/src/resolve/resolved-dns-answer.h
@@ -87,6 +87,8 @@ 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);
 
 #define _DNS_ANSWER_FOREACH(q, kk, a)                                   \