From f0956ae742c9df4bf165a56264d27f21975e884e Mon Sep 17 00:00:00 2001
From: fumiama <s862105088@gmail.com>
Date: Tue, 28 Dec 2021 16:18:16 +0800
Subject: [PATCH] =?UTF-8?q?=E5=AE=8C=E5=96=84=20router?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 gold/head/packet.go |  1 +
 gold/link/crypto.go | 11 +++++++++--
 gold/link/router.go | 12 +++++++++++-
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/gold/head/packet.go b/gold/head/packet.go
index 620e7fa..d67dc2a 100644
--- a/gold/head/packet.go
+++ b/gold/head/packet.go
@@ -62,6 +62,7 @@ func (p *Packet) FillHash() {
 	p.Hash = *(*[32]byte)(*(*unsafe.Pointer)(unsafe.Pointer(&sum)))
 }
 
+// IsVaildHash 验证 packet 合法性
 func (p *Packet) IsVaildHash() bool {
 	sum := blake2b.New256().Sum(p.Data)
 	return *(*[32]byte)(*(*unsafe.Pointer)(unsafe.Pointer(&sum))) == p.Hash
diff --git a/gold/link/crypto.go b/gold/link/crypto.go
index 489840a..6394d71 100644
--- a/gold/link/crypto.go
+++ b/gold/link/crypto.go
@@ -17,6 +17,8 @@ type Me struct {
 	privKey [32]byte
 	// 本机虚拟 ip
 	me net.IP
+	// 本机子网
+	subnet net.IPNet
 	// 本机 endpoint
 	myend *net.UDPAddr
 	// 本机活跃的所有连接
@@ -30,14 +32,19 @@ type Me struct {
 }
 
 // NewMe 设置本机参数
-func NewMe(privateKey *[32]byte, myIP string, myEndpoint string) (m Me) {
+func NewMe(privateKey *[32]byte, myipwithmask string, myEndpoint string) (m Me) {
 	m.privKey = *privateKey
 	var err error
 	m.myend, err = net.ResolveUDPAddr("udp", myEndpoint)
 	if err != nil {
 		panic(err)
 	}
-	m.me = net.ParseIP(myIP)
+	ip, cidr, err := net.ParseCIDR(myipwithmask)
+	if err != nil {
+		panic(err)
+	}
+	m.me = ip
+	m.subnet = *cidr
 	m.myconn, err = m.listen()
 	if err != nil {
 		panic(err)
diff --git a/gold/link/router.go b/gold/link/router.go
index e1eb3ad..9bdbce3 100644
--- a/gold/link/router.go
+++ b/gold/link/router.go
@@ -1,6 +1,7 @@
 package link
 
 import (
+	"encoding/binary"
 	"net"
 	"sync"
 
@@ -26,7 +27,7 @@ func (l *Link) Accept(ip net.IP) bool {
 
 // IsToMe 判断是否是发给自己的包
 func (l *Link) IsToMe(ip net.IP) bool {
-	return ip.Equal(l.me.me)
+	return ip.Equal(l.me.me) || ip.Equal(net.IPv4bcast) || isSubnetBcast(ip, &l.me.subnet)
 }
 
 // SetDefault 设置默认网关
@@ -69,3 +70,12 @@ func (r *Router) SetItem(ip *net.IPNet, l *Link) {
 	}
 	r.mu.Unlock()
 }
+
+func isSubnetBcast(ip net.IP, subnet *net.IPNet) bool {
+	if !subnet.Contains(ip) {
+		return false
+	}
+	maskr := make(net.IPMask, 4)
+	binary.LittleEndian.PutUint32(maskr[:], ^binary.LittleEndian.Uint32(subnet.Mask))
+	return ip.Mask(maskr).Equal(net.IP(maskr))
+}