From a1ac9cb356bbb39e2b422de74c8713a64958b11b Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Sun, 24 Mar 2019 12:55:59 -0700
Subject: [PATCH] ircd::net::dns: Expose more cache utils to public interface.

---
 include/ircd/net/dns.h |  4 +++
 ircd/net.cc            | 57 ++++++++++++++++++++++++++++++++++++++++++
 modules/s_dns.cc       | 23 -----------------
 modules/s_dns.h        |  9 +++----
 4 files changed, 64 insertions(+), 29 deletions(-)

diff --git a/include/ircd/net/dns.h b/include/ircd/net/dns.h
index bc79c56fa..61110b9b4 100644
--- a/include/ircd/net/dns.h
+++ b/include/ircd/net/dns.h
@@ -83,6 +83,10 @@ namespace ircd::net::dns::cache
 {
 	using closure = std::function<bool (const string_view &, const json::object &)>;
 
+	bool is_error(const json::object &rr);
+	time_t get_ttl(const json::object &rr);
+	bool expired(const json::object &rr, const time_t &rr_ts, const time_t &min_ttl);
+	bool expired(const json::object &rr, const time_t &rr_ts);
 	string_view make_type(const mutable_buffer &out, const string_view &);
 	string_view make_type(const mutable_buffer &out, const uint16_t &);
 
diff --git a/ircd/net.cc b/ircd/net.cc
index 91c023caa..5a9f17d87 100644
--- a/ircd/net.cc
+++ b/ircd/net.cc
@@ -3507,6 +3507,63 @@ ircd::net::dns::cache::make_type(const mutable_buffer &out,
 	};
 }
 
+bool
+ircd::net::dns::cache::expired(const json::object &rr,
+                               const time_t &rr_ts)
+{
+	static mods::import<conf::item<seconds>> min_ttl
+	{
+		"s_dns", "ircd::net::dns::cache::min_ttl"
+	};
+
+	static mods::import<conf::item<seconds>> error_ttl
+	{
+		"s_dns", "ircd::net::dns::cache::error_ttl"
+	};
+
+	const conf::item<seconds> &min_ttl_item
+	{
+		static_cast<conf::item<seconds> &>(min_ttl)
+	};
+
+	const conf::item<seconds> &error_ttl_item
+	{
+		static_cast<conf::item<seconds> &>(error_ttl)
+	};
+
+	const seconds &min_seconds(min_ttl_item);
+	const seconds &err_seconds(error_ttl_item);
+	const time_t &min
+	{
+		is_error(rr)?
+			err_seconds.count():
+			min_seconds.count()
+	};
+
+	return expired(rr, rr_ts, min);
+}
+
+bool
+ircd::net::dns::cache::expired(const json::object &rr,
+                               const time_t &rr_ts,
+                               const time_t &min_ttl)
+{
+	const auto ttl(get_ttl(rr));
+	return rr_ts + std::max(ttl, min_ttl) < ircd::time();
+}
+
+time_t
+ircd::net::dns::cache::get_ttl(const json::object &rr)
+{
+	return rr.get<time_t>("ttl", 0L);
+}
+
+bool
+ircd::net::dns::cache::is_error(const json::object &rr)
+{
+	return rr.has("error");
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 //
 // net/ipport.h
diff --git a/modules/s_dns.cc b/modules/s_dns.cc
index 5404cecc1..9ce418b4d 100644
--- a/modules/s_dns.cc
+++ b/modules/s_dns.cc
@@ -760,29 +760,6 @@ ircd::net::dns::cache::call_waiter(const string_view &type,
 	return true;
 }
 
-bool
-ircd::net::dns::cache::expired(const json::object &rr,
-                               const time_t &ts)
-{
-	const auto ttl(get_ttl(rr));
-	return ts + ttl < ircd::time();
-}
-
-time_t
-ircd::net::dns::cache::get_ttl(const json::object &rr)
-{
-	const seconds &min_ttl_s(min_ttl);
-	const seconds &err_ttl_s(error_ttl);
-	const time_t min_ttl_t(min_ttl_s.count());
-	const time_t err_ttl_t(err_ttl_s.count());
-	const time_t rr_ttl
-	{
-		rr.get<time_t>("ttl", err_ttl_t)
-	};
-
-	return std::max(rr_ttl, min_ttl_t);
-}
-
 //
 // cache room creation
 //
diff --git a/modules/s_dns.h b/modules/s_dns.h
index 9ed9ab142..527a2a5de 100644
--- a/modules/s_dns.h
+++ b/modules/s_dns.h
@@ -34,15 +34,12 @@ namespace ircd::net::dns::cache
 {
 	struct waiter;
 
-	static time_t get_ttl(const json::object &rr);
-	static bool expired(const json::object &rr, const time_t &ts);
-
 	static bool call_waiter(const string_view &, const string_view &, const json::array &, waiter &);
 	static void handle(const m::event &, m::vm::eval &);
 
-	extern conf::item<seconds> min_ttl;
-	extern conf::item<seconds> error_ttl;
-	extern conf::item<seconds> nxdomain_ttl;
+	extern conf::item<seconds> min_ttl IRCD_MODULE_EXPORT_DATA;
+	extern conf::item<seconds> error_ttl IRCD_MODULE_EXPORT_DATA;
+	extern conf::item<seconds> nxdomain_ttl IRCD_MODULE_EXPORT_DATA;
 
 	extern const m::room::id::buf room_id;
 	extern m::hookfn<m::vm::eval &> hook;