add some helper structs

admission/admission.go

@@ -3,3 +3,22 @@ package admission
 type Admission interface {
 	Admit(addr string) bool
 }
+
+type admissionList struct {
+	admissions []Admission
+}
+
+func AdmissionList(admissions ...Admission) Admission {
+	return &admissionList{
+		admissions: admissions,
+	}
+}
+
+func (p *admissionList) Admit(addr string) bool {
+	for _, admission := range p.admissions {
+		if admission != nil && !admission.Admit(addr) {
+			return false
+		}
+	}
+	return true
+}

auth/auth.go

@@ -4,3 +4,25 @@ package auth
 type Authenticator interface {
 	Authenticate(user, password string) bool
 }
+
+type authenticatorList struct {
+	authers []Authenticator
+}
+
+func AuthenticatorList(authers ...Authenticator) Authenticator {
+	return &authenticatorList{
+		authers: authers,
+	}
+}
+
+func (p *authenticatorList) Authenticate(user, password string) bool {
+	if len(p.authers) == 0 {
+		return true
+	}
+	for _, auther := range p.authers {
+		if auther != nil && auther.Authenticate(user, password) {
+			return true
+		}
+	}
+	return false
+}

bypass/bypass.go

@@ -5,3 +5,22 @@ type Bypass interface {
 	// Contains reports whether the bypass includes addr.
 	Contains(addr string) bool
 }
+
+type bypassList struct {
+	bypasses []Bypass
+}
+
+func BypassList(bypasses ...Bypass) Bypass {
+	return &bypassList{
+		bypasses: bypasses,
+	}
+}
+
+func (p *bypassList) Contains(addr string) bool {
+	for _, bypass := range p.bypasses {
+		if bypass != nil && bypass.Contains(addr) {
+			return true
+		}
+	}
+	return false
+}

chain/resovle.go

@@ -39,7 +39,7 @@ func resolve(ctx context.Context, network, addr string, r resolver.Resolver, hos
 			log.Error(err)
 		}
 		if len(ips) == 0 {
-			return "", fmt.Errorf("resolver: domain %s does not exists", host)
+			return "", fmt.Errorf("resolver: domain %s does not exist", host)
 		}
 		return net.JoinHostPort(ips[0].String(), port), nil
 	}