fix bug for listening unwanted packet

device.go

@@ -16,10 +16,6 @@ func getAdapter() *pcap.Interface {
 		}
 	}
 	// 输出IPv4地址
-	for _,v := range adapters[idx].Addresses {
-		if len(v.IP) == 4 {
-			log.Print("IPv4: ",v.IP)
-		}
-	}
+	log.Print("IPv4: ", getIPV4(&adapters[idx]))
 	return &adapters[idx]
 }

listener.go

@@ -20,7 +20,7 @@ func listen(adapter *pcap.Interface, port layers.TCPPort) {
 	check(err)
 
 	// 设置过滤器
-	err = handle.SetBPFFilter("tcp and dst port " + strconv.Itoa(int(port)))
+	err = handle.SetBPFFilter("tcp and dst port " + strconv.Itoa(int(port)) + " and ip dst " + getIPV4(adapter).String())
 	check(err)
 
 	// 建立数据源

utils.go

@@ -1,6 +1,11 @@
 package gopcap
 
-import "os"
+import (
+	"net"
+	"os"
+
+	"github.com/google/gopacket/pcap"
+)
 
 func check(err error) {
 	if err != nil {
@@ -20,4 +25,13 @@ func checkDirIsExist(filename string) bool {
 		return false
 	}
 	return true
+}
+
+func getIPV4(adapter *pcap.Interface) net.IP {
+	for _,v := range adapter.Addresses {
+		if len(v.IP) == 4 {
+			return v.IP
+		}
+	}
+	return net.IPv4(0,0,0,0)
 }