ircd::net: Add state for nodelay in socket w/ condition to elide; interface overloads.

include/ircd/net/sock_opts.h

@@ -20,6 +20,7 @@ namespace ircd::net
 	bool blocking(const socket &, system_t);
 	bool blocking(const socket &);
 	bool nopush(const socket &);
+	bool nodelay(const socket &, system_t);
 	bool nodelay(const socket &);
 	bool quickack(const socket &);
 	bool keepalive(const socket &);
@@ -35,6 +36,7 @@ namespace ircd::net
 	bool blocking(socket &, const bool, system_t);
 	bool blocking(socket &, const bool);
 	bool nopush(socket &, const bool);
+	bool nodelay(socket &, const bool, system_t);
 	bool nodelay(socket &, const bool);
 	bool quickack(socket &, const bool);
 	bool keepalive(socket &, const bool);

include/ircd/net/socket.h

@@ -74,6 +74,7 @@ ircd::net::socket
 	bool timer_set {false};                      // boolean lockout
 	bool timedout {false};
 	bool fini {false};
+	mutable bool _nodelay {false};               // userspace tracking only
 
 	void call_user(const eptr_handler &, const error_code &) noexcept;
 	void call_user(const ec_handler &, const error_code &) noexcept;

ircd/net.cc

@@ -1081,10 +1081,22 @@ ircd::net::quickack(socket &socket,
 bool
 ircd::net::nodelay(socket &socket,
                    const bool b)
+{
+	if(likely(nodelay(socket) != b))
+		nodelay(socket, b, system);
+
+	return true;
+}
+
+bool
+ircd::net::nodelay(socket &socket,
+                   const bool b,
+                   system_t)
 {
 	const ip::tcp::no_delay option{b};
 	ip::tcp::socket &sd(socket);
 	sd.set_option(option);
+	socket._nodelay = b;
 	return true;
 }
 
@@ -1279,12 +1291,20 @@ ircd::net::quickack(const socket &socket)
 #endif
 
 bool
-ircd::net::nodelay(const socket &socket)
+ircd::net::nodelay(const socket &socket,
+                   system_t)
 {
 	const ip::tcp::socket &sd(socket);
 	ip::tcp::no_delay option;
 	sd.get_option(option);
-	return option.value();
+	mutable_cast(socket)._nodelay = option.value();
+	return socket._nodelay;
+}
+
+bool
+ircd::net::nodelay(const socket &socket)
+{
+	return socket._nodelay;
 }
 
 bool