Add basic support for DoH3 (#7677)

plugin/metrics/vars/vars.go

@@ -76,6 +76,13 @@ var (
 		Help:      "Counter of DoH responses per server and http status code.",
 	}, []string{"server", "status"})
 
+	HTTPS3ResponsesCount = promauto.NewCounterVec(prometheus.CounterOpts{
+		Namespace: plugin.Namespace,
+		Subsystem: subsystem,
+		Name:      "https3_responses_total",
+		Help:      "Counter of DoH3 responses per server and http status code.",
+	}, []string{"server", "status"})
+
 	QUICResponsesCount = promauto.NewCounterVec(prometheus.CounterOpts{
 		Namespace: plugin.Namespace,
 		Subsystem: subsystem,

plugin/pkg/parse/transport.go

@@ -27,14 +27,17 @@ func Transport(s string) (trans string, addr string) {
 		s = s[len(transport.GRPC+"://"):]
 		return transport.GRPC, s
 
+	case strings.HasPrefix(s, transport.HTTPS3+"://"):
+		s = s[len(transport.HTTPS3+"://"):]
+		return transport.HTTPS3, s
+
 	case strings.HasPrefix(s, transport.HTTPS+"://"):
 		s = s[len(transport.HTTPS+"://"):]
-
 		return transport.HTTPS, s
+
 	case strings.HasPrefix(s, transport.UNIX+"://"):
 		s = s[len(transport.UNIX+"://"):]
 		return transport.UNIX, s
 	}
-
 	return transport.DNS, s
 }

plugin/pkg/transport/transport.go

@@ -2,12 +2,13 @@ package transport
 
 // These transports are supported by CoreDNS.
 const (
-	DNS   = "dns"
-	TLS   = "tls"
-	QUIC  = "quic"
-	GRPC  = "grpc"
-	HTTPS = "https"
-	UNIX  = "unix"
+	DNS    = "dns"
+	TLS    = "tls"
+	QUIC   = "quic"
+	GRPC   = "grpc"
+	HTTPS  = "https"
+	HTTPS3 = "https3"
+	UNIX   = "unix"
 )
 
 // Port numbers for the various transports.