fix: use nic mtu that minus packet header

config/cfg.go

@@ -15,7 +15,7 @@ type Config struct {
 	PrivateKey string `yaml:"PrivateKey"`
 	Network    string `yaml:"Network"` // Network udp, tcp or ws (WIP)
 	EndPoint   string `yaml:"EndPoint"`
-	MTU        int64  `yaml:"MTU"`
+	MTU        int64  `yaml:"MTU"` // MTU of nic (will minus packet header len)
 	SpeedLoop  uint16 `yaml:"SpeedLoop"`
 	Mask       uint64 `yaml:"Mask"` // Mask 是异或报文所用掩码, 必须保证各端统一
 	Peers      []Peer `yaml:"Peers"`
@@ -34,7 +34,7 @@ type Peer struct {
 	AllowTrans       bool     `yaml:"AllowTrans"`
 	UseZstd          bool     `yaml:"UseZstd"`
 	DoublePacket     bool     `yaml:"DoublePacket"`
-	MTU              int64    `yaml:"MTU"`
+	MTU              int64    `yaml:"MTU"` // MTU of PDU passed to p2p
 	MTURandomRange   int64    `yaml:"MTURandomRange"`
 }
 

gold/link/me.go

@@ -39,7 +39,7 @@ type Me struct {
 	// 本机监听的连接端点, 也用于向对端直接发送报文
 	conn p2p.Conn
 	// 本机网卡
-	nic lower.NICIO
+	nic *lower.NICIO
 	// 本机路由表
 	router *Router
 	// 本机未接收完全分片池
@@ -60,11 +60,17 @@ type MyConfig struct {
 	Network                          string
 	NetworkConfigs                   []any
 	PrivateKey                       *[32]byte
-	NIC                              lower.NICIO
+	NICConfig                        *NICConfig
 	SrcPort, DstPort, MTU, SpeedLoop uint16
 	Mask                             uint64
 }
 
+type NICConfig struct {
+	IP     net.IP
+	SubNet *net.IPNet
+	CIDRs  []string
+}
+
 // NewMe 设置本机参数
 func NewMe(cfg *MyConfig) (m Me) {
 	m.privKey = *cfg.PrivateKey
@@ -89,7 +95,6 @@ func NewMe(cfg *MyConfig) (m Me) {
 		panic(err)
 	}
 	m.connections = make(map[string]*Link)
-	m.nic = cfg.NIC
 	m.router = &Router{
 		list:  make([]*net.IPNet, 1, 16),
 		table: make(map[string]*Link, 16),
@@ -98,7 +103,13 @@ func NewMe(cfg *MyConfig) (m Me) {
 	m.router.SetDefault(nil)
 	m.srcport = cfg.SrcPort
 	m.dstport = cfg.DstPort
-	m.mtu = cfg.MTU & 0xfff8
+	m.mtu = (cfg.MTU - head.PacketHeadLen) & 0xfff8
+	if cfg.NICConfig != nil {
+		m.nic = lower.NewNIC(
+			cfg.NICConfig.IP, cfg.NICConfig.SubNet,
+			strconv.FormatUint(uint64(m.MTU()), 10), cfg.NICConfig.CIDRs...,
+		)
+	}
 	m.speedloop = cfg.SpeedLoop
 	if m.speedloop == 0 {
 		m.speedloop = 4096

gold/link/peer.go

@@ -33,7 +33,7 @@ func (m *Me) AddPeer(cfg *PeerConfig) (l *Link) {
 	if ok {
 		return
 	}
-	if m.mtu == 0 {
+	if cfg.MTU == 0 {
 		panic("invalid mtu for peer " + cfg.PeerIP)
 	}
 	l = &Link{

lower/nic.go

@@ -1,7 +1,6 @@
 package lower
 
 import (
-	"io"
 	"net"
 	"os"
 	"os/exec"
@@ -11,14 +10,8 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-type NICIO interface {
-	io.ReadWriteCloser
-	Up()
-	Down()
-}
-
-// NIC 虚拟网卡
-type NIC struct {
+// NICIO 虚拟网卡
+type NICIO struct {
 	ifce     *water.Interface
 	ip       net.IP
 	subnet   *net.IPNet
@@ -31,7 +24,7 @@ type NIC struct {
 // 网卡地址为 ip, 所属子网为 subnet
 // 以本网卡为下一跳的所有子网为 cidrs
 // cidrs 不包括本网卡 subnet
-func NewNIC(ip net.IP, subnet *net.IPNet, mtu string, cidrs ...string) NICIO {
+func NewNIC(ip net.IP, subnet *net.IPNet, mtu string, cidrs ...string) *NICIO {
 	ifce, err := water.New(water.Config{DeviceType: water.TUN})
 	if err != nil {
 		logrus.Error(err)
@@ -41,7 +34,7 @@ func NewNIC(ip net.IP, subnet *net.IPNet, mtu string, cidrs ...string) NICIO {
 	if bitsn != 32 {
 		panic("mask len " + strconv.Itoa(bitsn) + " is not supported")
 	}
-	n := &NIC{
+	n := &NICIO{
 		ifce:     ifce,
 		ip:       ip,
 		subnet:   subnet,
@@ -53,16 +46,16 @@ func NewNIC(ip net.IP, subnet *net.IPNet, mtu string, cidrs ...string) NICIO {
 }
 
 // Read 匹配 PacketsIO Interface
-func (nc *NIC) Read(buf []byte) (int, error) {
+func (nc *NICIO) Read(buf []byte) (int, error) {
 	return nc.ifce.Read(buf)
 }
 
-func (nc *NIC) Write(packet []byte) (int, error) {
+func (nc *NICIO) Write(packet []byte) (int, error) {
 	return nc.ifce.Write(packet)
 }
 
 // Close 关闭网卡
-func (n *NIC) Close() error {
+func (n *NICIO) Close() error {
 	return n.ifce.Close()
 }
 

lower/tun_darwin.go

@@ -5,7 +5,7 @@ package lower
 
 import "net"
 
-func (n *NIC) Up() {
+func (n *NICIO) Up() {
 	execute("ifconfig", n.ifce.Name(), "mtu", n.mtu) // max: 9159
 	execute(
 		"ifconfig", n.ifce.Name(),
@@ -19,7 +19,7 @@ func (n *NIC) Up() {
 	}
 }
 
-func (n *NIC) Down() {
+func (n *NICIO) Down() {
 	execute("route", "delete", n.subnet.String(), "-interface", n.ifce.Name())
 	for _, c := range n.cidrs {
 		execute("route", "delete", c, "-interface", n.ifce.Name())

lower/tun_linux.go

@@ -3,7 +3,7 @@
 
 package lower
 
-func (n *NIC) Up() {
+func (n *NICIO) Up() {
 	execute("/sbin/ip", "link", "set", "dev", n.ifce.Name(), "mtu", n.mtu)
 	execute("/sbin/ip", "addr", "add", n.rawipnet, "dev", n.ifce.Name())
 	execute("/sbin/ip", "link", "set", "dev", n.ifce.Name(), "up")
@@ -12,7 +12,7 @@ func (n *NIC) Up() {
 	}
 }
 
-func (n *NIC) Down() {
+func (n *NICIO) Down() {
 	for _, c := range n.cidrs {
 		execute("/sbin/ip", "route", "del", c, "dev", n.ifce.Name())
 	}

lower/tun_stub.go

@@ -3,10 +3,10 @@
 
 package lower
 
-func (n *NIC) Up() {
+func (n *NICIO) Up() {
 	panic("not support lower on this os now")
 }
 
-func (n *NIC) Down() {
+func (n *NICIO) Down() {
 	panic("not support lower on this os now")
 }

lower/tun_windows.go

@@ -5,7 +5,7 @@ package lower
 
 import "net"
 
-func (n *NIC) Up() {
+func (n *NICIO) Up() {
 	execute("cmd", "/c", "netsh interface ip set address name=\""+n.ifce.Name()+"\" source=static addr=\""+n.ip.String()+"\" mask=\""+(net.IP)(n.subnet.Mask).String()+"\" gateway=none")
 	execute("cmd", "/c", "netsh interface ipv4 set subinterface \""+n.ifce.Name()+"\" mtu="+n.mtu)
 	for _, c := range n.cidrs {
@@ -17,7 +17,7 @@ func (n *NIC) Up() {
 	}
 }
 
-func (n *NIC) Down() {
+func (n *NICIO) Down() {
 	// execute("netsh", "interface", "set", "interface", n.ifce.Name(), "disabled")
 	for _, c := range n.cidrs {
 		ip, _, err := net.ParseCIDR(c)

main.go

@@ -15,6 +15,7 @@ import (
 	"github.com/sirupsen/logrus"
 
 	"github.com/fumiama/WireGold/config"
+	"github.com/fumiama/WireGold/gold/head"
 	"github.com/fumiama/WireGold/helper"
 	"github.com/fumiama/WireGold/upper"
 	"github.com/fumiama/WireGold/upper/services/wg"
@@ -144,8 +145,8 @@ func main() {
 	if c.EndPoint == "" {
 		displayHelp("nil endpoint")
 	}
-	if c.MTU == 0 {
-		displayHelp("nil mtu")
+	if c.MTU <= head.PacketHeadLen {
+		displayHelp("invalid mtu")
 	}
 	w, err := wg.NewWireGold(&c)
 	if err != nil {

upper/services/wg/wg.go

@@ -17,7 +17,6 @@ import (
 	"github.com/fumiama/WireGold/config"
 	"github.com/fumiama/WireGold/gold/link"
 	"github.com/fumiama/WireGold/helper"
-	"github.com/fumiama/WireGold/lower"
 )
 
 const suffix32 = "㴄"
@@ -104,12 +103,16 @@ func (wg *WG) init(srcport, dstport uint16) {
 		MyEndpoint:   wg.c.EndPoint,
 		Network:      wg.c.Network,
 		PrivateKey:   &wg.key,
-		NIC:          lower.NewNIC(myip, mysubnet, strconv.FormatInt(wg.c.MTU, 10), cidrs...),
-		SrcPort:      srcport,
-		DstPort:      dstport,
-		MTU:          uint16(wg.c.MTU),
-		SpeedLoop:    wg.c.SpeedLoop,
-		Mask:         wg.c.Mask,
+		NICConfig: &link.NICConfig{
+			IP:     myip,
+			SubNet: mysubnet,
+			CIDRs:  cidrs,
+		},
+		SrcPort:   srcport,
+		DstPort:   dstport,
+		MTU:       uint16(wg.c.MTU),
+		SpeedLoop: wg.c.SpeedLoop,
+		Mask:      wg.c.Mask,
 	})
 
 	for _, peer := range wg.c.Peers {