From 309c08b26ee2ed2ef5d6139bd85e80e670f6a7e0 Mon Sep 17 00:00:00 2001
From: xishang0128 <xishang02@gmail.com>
Date: Sat, 9 Mar 2024 17:49:36 +0800
Subject: [PATCH] feat: Supports dialer IP4P address convert
 https://github.com/heiher/natmap/wiki/faq

---
 component/dialer/dialer.go | 29 ++++++++++++++++++++++++++++-
 config/config.go           |  1 +
 hub/executor/executor.go   |  1 +
 3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/component/dialer/dialer.go b/component/dialer/dialer.go
index 070d98b816..aa8776bb36 100644
--- a/component/dialer/dialer.go
+++ b/component/dialer/dialer.go
@@ -7,12 +7,14 @@ import (
 	"net"
 	"net/netip"
 	"os"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
 
 	"github.com/metacubex/mihomo/component/resolver"
 	"github.com/metacubex/mihomo/constant/features"
+	"github.com/metacubex/mihomo/log"
 )
 
 const (
@@ -24,6 +26,7 @@ type dialFunc func(ctx context.Context, network string, ips []netip.Addr, port s
 
 var (
 	dialMux                      sync.Mutex
+	IP4PEnable                   bool
 	actualSingleStackDialContext = serialSingleStackDialContext
 	actualDualStackDialContext   = serialDualStackDialContext
 	tcpConcurrent                = false
@@ -128,7 +131,13 @@ func dialContext(ctx context.Context, network string, destination netip.Addr, po
 		return dialContextHooked(ctx, network, destination, port)
 	}
 
-	address := net.JoinHostPort(destination.String(), port)
+	var address string
+	if IP4PEnable {
+		NewDestination, NewPort := lookupIP4P(destination.String(), port)
+		address = net.JoinHostPort(NewDestination, NewPort)
+	} else {
+		address = net.JoinHostPort(destination.String(), port)
+	}
 
 	netDialer := opt.netDialer
 	switch netDialer.(type) {
@@ -383,3 +392,21 @@ func NewDialer(options ...Option) Dialer {
 	opt := applyOptions(options...)
 	return Dialer{Opt: *opt}
 }
+
+// kanged from https://github.com/heiher/frp/blob/ip4p/client/ip4p.go
+
+func lookupIP4P(addr string, port string) (string, string) {
+	ip := net.ParseIP(addr)
+	if ip[0] == 0x20 && ip[1] == 0x01 &&
+		ip[2] == 0x00 && ip[3] == 0x00 {
+		addr = net.IPv4(ip[12], ip[13], ip[14], ip[15]).String()
+		port = strconv.Itoa(int(ip[10])<<8 + int(ip[11]))
+		log.Debugln("Convert IP4P address %s to %s", ip, net.JoinHostPort(addr, port))
+		return addr, port
+	}
+	return addr, port
+}
+
+func DialWithIP4PTranslation(enableIP4PTranslation bool) {
+	IP4PEnable = enableIP4PTranslation
+}
diff --git a/config/config.go b/config/config.go
index d4b9ad89c9..8fec0bab55 100644
--- a/config/config.go
+++ b/config/config.go
@@ -169,6 +169,7 @@ type Experimental struct {
 	Fingerprints     []string `yaml:"fingerprints"`
 	QUICGoDisableGSO bool     `yaml:"quic-go-disable-gso"`
 	QUICGoDisableECN bool     `yaml:"quic-go-disable-ecn"`
+	IP4PEnable       bool     `yaml:"dialer-ip4p-convert"`
 }
 
 // Config is mihomo config manager
diff --git a/hub/executor/executor.go b/hub/executor/executor.go
index 14e826d7a9..9ae5e421e5 100644
--- a/hub/executor/executor.go
+++ b/hub/executor/executor.go
@@ -197,6 +197,7 @@ func updateExperimental(c *config.Config) {
 	if c.Experimental.QUICGoDisableECN {
 		_ = os.Setenv("QUIC_GO_DISABLE_ECN", strconv.FormatBool(true))
 	}
+	dialer.DialWithIP4PTranslation(c.Experimental.IP4PEnable)
 }
 
 func updateNTP(c *config.NTP) {