From ab45133ab4826359ca9a5ed50b68150eb462c8ef Mon Sep 17 00:00:00 2001
From: Perttu Ahola <celeron55@gmail.com>
Date: Tue, 27 Nov 2012 09:38:21 +0200
Subject: [PATCH] Add congestion control settings to minetest.conf

---
 minetest.conf.example   |  5 +++++
 src/connection.cpp      | 28 ++++++++++++++++++++++------
 src/connection.h        |  6 +++++-
 src/defaultsettings.cpp | 13 ++++++++-----
 4 files changed, 40 insertions(+), 12 deletions(-)

diff --git a/minetest.conf.example b/minetest.conf.example
index 64cb87727..071b97c65 100644
--- a/minetest.conf.example
+++ b/minetest.conf.example
@@ -198,3 +198,8 @@
 #dedicated_server_step = 0.1
 # Can be set to true to disable shutting down on invalid world data
 #ignore_world_load_errors = false
+# Congestion control parameters
+# time in seconds, rate in ~500B packets
+#congestion_control_aim_rtt = 0.2
+#congestion_control_max_rate = 400
+#congestion_control_min_rate = 10
diff --git a/src/connection.cpp b/src/connection.cpp
index 4f5d095e5..ed5a752be 100644
--- a/src/connection.cpp
+++ b/src/connection.cpp
@@ -25,6 +25,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "util/serialize.h"
 #include "util/numeric.h"
 #include "util/string.h"
+#include "settings.h"
 
 namespace con
 {
@@ -466,7 +467,10 @@ Peer::Peer(u16 a_id, Address a_address):
 	m_sendtime_accu(0),
 	m_max_packets_per_second(10),
 	m_num_sent(0),
-	m_max_num_sent(0)
+	m_max_num_sent(0),
+	congestion_control_aim_rtt(0.2),
+	congestion_control_max_rate(400),
+	congestion_control_min_rate(10)
 {
 }
 Peer::~Peer()
@@ -477,15 +481,15 @@ void Peer::reportRTT(float rtt)
 {
 	if(rtt >= 0.0){
 		if(rtt < 0.01){
-			if(m_max_packets_per_second < 400)
+			if(m_max_packets_per_second < congestion_control_max_rate)
 				m_max_packets_per_second += 10;
-		} else if(rtt < 0.2){
-			if(m_max_packets_per_second < 100)
+		} else if(rtt < congestion_control_aim_rtt){
+			if(m_max_packets_per_second < congestion_control_max_rate)
 				m_max_packets_per_second += 2;
 		} else {
 			m_max_packets_per_second *= 0.8;
-			if(m_max_packets_per_second < 10)
-				m_max_packets_per_second = 10;
+			if(m_max_packets_per_second < congestion_control_min_rate)
+				m_max_packets_per_second = congestion_control_min_rate;
 		}
 	}
 
@@ -891,12 +895,24 @@ void Connection::receive()
 
 void Connection::runTimeouts(float dtime)
 {
+	float congestion_control_aim_rtt
+			= g_settings->getFloat("congestion_control_aim_rtt");
+	float congestion_control_max_rate
+			= g_settings->getFloat("congestion_control_max_rate");
+	float congestion_control_min_rate
+			= g_settings->getFloat("congestion_control_min_rate");
+
 	core::list<u16> timeouted_peers;
 	core::map<u16, Peer*>::Iterator j;
 	j = m_peers.getIterator();
 	for(; j.atEnd() == false; j++)
 	{
 		Peer *peer = j.getNode()->getValue();
+
+		// Update congestion control values
+		peer->congestion_control_aim_rtt = congestion_control_aim_rtt;
+		peer->congestion_control_max_rate = congestion_control_max_rate;
+		peer->congestion_control_min_rate = congestion_control_min_rate;
 		
 		/*
 			Check peer timeout
diff --git a/src/connection.h b/src/connection.h
index f88e813a3..f99cd1bf9 100644
--- a/src/connection.h
+++ b/src/connection.h
@@ -394,7 +394,11 @@ public:
 	float m_max_packets_per_second;
 	int m_num_sent;
 	int m_max_num_sent;
-	
+
+	// Updated from configuration by Connection
+	float congestion_control_aim_rtt;
+	float congestion_control_max_rate;
+	float congestion_control_min_rate;
 private:
 };
 
diff --git a/src/defaultsettings.cpp b/src/defaultsettings.cpp
index 8ce9cb1fb..d186427e7 100644
--- a/src/defaultsettings.cpp
+++ b/src/defaultsettings.cpp
@@ -106,6 +106,11 @@ void set_default_settings(Settings *settings)
 	settings->setDefault("sound_volume", "0.8");
 	settings->setDefault("desynchronize_mapblock_texture_animation", "true");
 
+	settings->setDefault("mip_map", "false");
+	settings->setDefault("anisotropic_filter", "false");
+	settings->setDefault("bilinear_filter", "false");
+	settings->setDefault("trilinear_filter", "false");
+
 	// Server stuff
 	// "map-dir" doesn't exist by default.
 	settings->setDefault("default_game", "minetest");
@@ -142,10 +147,8 @@ void set_default_settings(Settings *settings)
 	settings->setDefault("full_block_send_enable_min_time_from_building", "2.0");
 	settings->setDefault("dedicated_server_step", "0.1");
 	settings->setDefault("ignore_world_load_errors", "false");
-	settings->setDefault("mip_map", "false");
-	settings->setDefault("anisotropic_filter", "false");
-	settings->setDefault("bilinear_filter", "false");
-	settings->setDefault("trilinear_filter", "false");
-
+	settings->setDefault("congestion_control_aim_rtt", "0.2");
+	settings->setDefault("congestion_control_max_rate", "400");
+	settings->setDefault("congestion_control_min_rate", "10");
 }