From b593df44b75b4ca21bef62bbfe736fffe0bc9116 Mon Sep 17 00:00:00 2001
From: Toby <tobyxdd@gmail.com>
Date: Thu, 3 Feb 2022 20:37:08 -0800
Subject: [PATCH 1/2] feat: disable quic-go PMTUD due to broken implementation

---
 cmd/client.go |  2 +-
 cmd/config.go | 26 ++++++++++++--------------
 cmd/server.go |  2 +-
 3 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/cmd/client.go b/cmd/client.go
index ac9bc58..dffb732 100644
--- a/cmd/client.go
+++ b/cmd/client.go
@@ -67,7 +67,7 @@ func client(config *clientConfig) {
 		InitialConnectionReceiveWindow: config.ReceiveWindow,
 		MaxConnectionReceiveWindow:     config.ReceiveWindow,
 		KeepAlive:                      true,
-		DisablePathMTUDiscovery:        config.DisableMTUDiscovery,
+		DisablePathMTUDiscovery:        true, // Ref: https://github.com/lucas-clemente/quic-go/issues/3327
 		EnableDatagrams:                true,
 	}
 	if config.ReceiveWindowConn == 0 {
diff --git a/cmd/config.go b/cmd/config.go
index 742e4d3..2049599 100644
--- a/cmd/config.go
+++ b/cmd/config.go
@@ -49,7 +49,6 @@ type serverConfig struct {
 	ReceiveWindowConn   uint64 `json:"recv_window_conn"`
 	ReceiveWindowClient uint64 `json:"recv_window_client"`
 	MaxConnClient       int    `json:"max_conn_client"`
-	DisableMTUDiscovery bool   `json:"disable_mtu_discovery"`
 	IPv6Only            bool   `json:"ipv6_only"`
 	Resolver            string `json:"resolver"`
 }
@@ -139,19 +138,18 @@ type clientConfig struct {
 		Listen  string `json:"listen"`
 		Timeout int    `json:"timeout"`
 	} `json:"tproxy_udp"`
-	ACL                 string `json:"acl"`
-	MMDB                string `json:"mmdb"`
-	Obfs                string `json:"obfs"`
-	Auth                []byte `json:"auth"`
-	AuthString          string `json:"auth_str"`
-	ALPN                string `json:"alpn"`
-	ServerName          string `json:"server_name"`
-	Insecure            bool   `json:"insecure"`
-	CustomCA            string `json:"ca"`
-	ReceiveWindowConn   uint64 `json:"recv_window_conn"`
-	ReceiveWindow       uint64 `json:"recv_window"`
-	DisableMTUDiscovery bool   `json:"disable_mtu_discovery"`
-	Resolver            string `json:"resolver"`
+	ACL               string `json:"acl"`
+	MMDB              string `json:"mmdb"`
+	Obfs              string `json:"obfs"`
+	Auth              []byte `json:"auth"`
+	AuthString        string `json:"auth_str"`
+	ALPN              string `json:"alpn"`
+	ServerName        string `json:"server_name"`
+	Insecure          bool   `json:"insecure"`
+	CustomCA          string `json:"ca"`
+	ReceiveWindowConn uint64 `json:"recv_window_conn"`
+	ReceiveWindow     uint64 `json:"recv_window"`
+	Resolver          string `json:"resolver"`
 }
 
 func (c *clientConfig) Check() error {
diff --git a/cmd/server.go b/cmd/server.go
index 5d6eec6..081bf7d 100644
--- a/cmd/server.go
+++ b/cmd/server.go
@@ -70,7 +70,7 @@ func server(config *serverConfig) {
 		MaxConnectionReceiveWindow:     config.ReceiveWindowClient,
 		MaxIncomingStreams:             int64(config.MaxConnClient),
 		KeepAlive:                      true,
-		DisablePathMTUDiscovery:        config.DisableMTUDiscovery,
+		DisablePathMTUDiscovery:        true, // Ref: https://github.com/lucas-clemente/quic-go/issues/3327
 		EnableDatagrams:                true,
 	}
 	if config.ReceiveWindowConn == 0 {

From a4a4130ba128df47782ca06807818300f612af19 Mon Sep 17 00:00:00 2001
From: Toby <tobyxdd@gmail.com>
Date: Thu, 3 Feb 2022 20:54:30 -0800
Subject: [PATCH 2/2] fix: zero initMaxDatagramSize in brutal CC (wtf...)

---
 pkg/congestion/brutal.go | 5 ++++-
 pkg/congestion/pacer.go  | 5 ++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/pkg/congestion/brutal.go b/pkg/congestion/brutal.go
index 71d3467..f11ef46 100644
--- a/pkg/congestion/brutal.go
+++ b/pkg/congestion/brutal.go
@@ -6,6 +6,8 @@ import (
 )
 
 const (
+	initMaxDatagramSize = 1252
+
 	pktInfoSlotCount = 4
 	minSampleCount   = 50
 	minAckRate       = 0.75
@@ -28,7 +30,8 @@ type pktInfo struct {
 
 func NewBrutalSender(bps congestion.ByteCount) *BrutalSender {
 	bs := &BrutalSender{
-		bps: bps,
+		bps:             bps,
+		maxDatagramSize: initMaxDatagramSize,
 	}
 	bs.pacer = newPacer(func() congestion.ByteCount {
 		return congestion.ByteCount(float64(bs.bps) / bs.getAckRate())
diff --git a/pkg/congestion/pacer.go b/pkg/congestion/pacer.go
index 100b14f..d074ac0 100644
--- a/pkg/congestion/pacer.go
+++ b/pkg/congestion/pacer.go
@@ -7,9 +7,8 @@ import (
 )
 
 const (
-	initMaxDatagramSize = 1252
-	maxBurstPackets     = 10
-	minPacingDelay      = time.Millisecond
+	maxBurstPackets = 10
+	minPacingDelay  = time.Millisecond
 )
 
 // The pacer implements a token bucket pacing algorithm.