From 86df5510d49c491ceedb1efe2ab83d3f83dc32f4 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Mon, 6 Feb 2023 11:58:48 -0800
Subject: [PATCH] ircd::net::dns: Optimize query w/ internal lookup priority
 when enabled by conf.

---
 ircd/net_dns_netdb.cc | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/ircd/net_dns_netdb.cc b/ircd/net_dns_netdb.cc
index 4981b9f82..1aaa348e1 100644
--- a/ircd/net_dns_netdb.cc
+++ b/ircd/net_dns_netdb.cc
@@ -17,6 +17,7 @@ namespace ircd::net::dns
 
 	static bool netdb_ready;
 	extern conf::item<bool> netdb_enable;
+	extern conf::item<bool> netdb_internal;
 	extern const std::map<pair<string_view>, uint16_t> service_ports;
 	extern const std::map<pair<uint16_t, string_view>, string_view> service_names;
 }
@@ -55,6 +56,14 @@ ircd::net::dns::netdb_enable
 	{ "default",  true                        },
 };
 
+[[gnu::visibility("internal")]]
+decltype(ircd::net::dns::netdb_internal)
+ircd::net::dns::netdb_internal
+{
+	{ "name",     "ircd.net.dns.netdb.internal" },
+	{ "default",  true                          },
+};
+
 void
 ircd::net::dns::init::service_init()
 {
@@ -115,6 +124,10 @@ try
 	thread_local struct ::servent res, *ent {nullptr};
 	thread_local char _name[32], _prot[32], buf[2048];
 
+	if(likely(netdb_internal))
+		if((res.s_port = _service_port(name, prot)))
+			return res.s_port;
+
 	const mods::ldso::exceptions enable {false};
 	const prof::syscall_usage_warning timer
 	{
@@ -210,6 +223,13 @@ try
 	thread_local struct ::servent res, *ent {nullptr};
 	thread_local char _prot[32], buf[2048];
 
+	if(likely(netdb_internal))
+	{
+		string_view ret;
+		if((ret = strlcpy(out, _service_name(port, prot))))
+			return ret;
+	}
+
 	const mods::ldso::exceptions enable {false};
 	const prof::syscall_usage_warning timer
 	{