dns lookup concurrently

scanner.go

@@ -17,6 +17,24 @@ var TLSDictionary = map[uint16]string{
 }
 
 func ScanTLS(host Host, out chan<- string) {
+	if host.IP == nil {
+		ips, err := net.LookupIP(host.Origin)
+		if err != nil {
+			slog.Debug("Failed to lookup", "origin", host.Origin, "err", err)
+			return
+		}
+		var arr []net.IP
+		for _, ip := range ips {
+			if ip.To4() != nil || enableIPv6 {
+				arr = append(arr, ip)
+			}
+		}
+		if len(arr) == 0 {
+			slog.Debug("No IP found", "origin", host.Origin)
+			return
+		}
+		host.IP = arr[0]
+	}
 	hostPort := net.JoinHostPort(host.IP.String(), strconv.Itoa(port))
 	conn, err := net.DialTimeout("tcp", hostPort, time.Duration(timeout)*time.Second)
 	if err != nil {

utils.go

@@ -7,6 +7,7 @@ import (
 	"log/slog"
 	"net"
 	"net/netip"
+	"regexp"
 	"strings"
 )
 
@@ -73,17 +74,12 @@ func Iterate(reader io.Reader) <-chan Host {
 				}
 				continue
 			}
-			ips, err := net.LookupIP(line)
-			if err == nil {
+			if ValidateDomainName(line) {
 				// domain
-				for _, ip = range ips {
-					if ip.To4() != nil || enableIPv6 {
-						hostChan <- Host{
-							IP:     ip,
-							Origin: line,
-							Type:   HostTypeDomain,
-						}
-					}
+				hostChan <- Host{
+					IP:     nil,
+					Origin: line,
+					Type:   HostTypeDomain,
 				}
 				continue
 			}
@@ -95,6 +91,10 @@ func Iterate(reader io.Reader) <-chan Host {
 	}()
 	return hostChan
 }
+func ValidateDomainName(domain string) bool {
+	r := regexp.MustCompile(`(?m)^[A-Za-z0-9\-.]+$`)
+	return r.MatchString(domain)
+}
 func ExistOnlyOne(arr []string) bool {
 	exist := false
 	for _, item := range arr {