test

internal/protocol/dhcp/dhcp.go

@@ -5,6 +5,8 @@ import (
 	"encoding/binary"
 	"fmt"
 	"net"
+	"strings"
+	"time"
 
 	"github.com/google/gopacket/layers"
 
@@ -12,7 +14,7 @@ import (
 	gl "github.com/google/gopacket/layers"
 )
 
-func doDiscover(address string) (map[string]string, error) {
+func doDiscoverV4(address string) (map[string]string, error) {
 
 	localAddr, err := net.ResolveUDPAddr("udp", address+":68")
 	if err != nil {
@@ -22,10 +24,13 @@ func doDiscover(address string) (map[string]string, error) {
 	if err != nil {
 		return nil, err
 	}
-	defer conn.Close()
+	conn.SetDeadline(time.Now().Add(time.Second * 3))
+	defer func() {
+		conn.Close()
+	}()
 
 	sendDiscover(conn) // broadcast 255.255.255.255:67
-	return readOffer(conn) // unicast
+	return readOffer(conn)
 
 }
 
@@ -104,7 +109,15 @@ func readOffer(conn *net.UDPConn) (map[string]string, error) {
 					offerOptions["ROUTER"] = optDataToIPString(opt.Data)
 					break
 				case gl.DHCPOptDNS:
-					offerOptions["DNS_SERVER"] = optDataToIPString(opt.Data)
+					cnt := len(opt.Data) / 4
+					var dns []string
+					ipStr := optDataToIPString(opt.Data[0:4])
+					dns = append(dns, ipStr)
+					if cnt > 1 {
+						ipStr := optDataToIPString(opt.Data[4:8])
+						dns = append(dns, ipStr)
+					}
+					offerOptions["DOMAIN_NAME_SERVER"] = strings.Join(dns, ",")
 					break
 				}
 			}

internal/protocol/dhcp/dhcp_test.go

@@ -5,7 +5,7 @@ import (
 )
 
 func TestDHCP(t *testing.T) {
-	offer, err := doDiscover("192.168.1.203")
+	offer, err := doDiscoverV4("192.168.1.203")
 	if err != nil {
 		t.Errorf("ERROR : %s", err.Error())
 	}