feat: complete basic functions

Support http,dns and mysql connection. Support custom http, dns response. Support dns rebinding.
Support mysql load local files and jdbc deserialize exploit.

internal/newdns/event.go

@@ -0,0 +1,85 @@
+package newdns
+
+import "github.com/miekg/dns"
+
+// Event denotes an event type emitted to the logger.
+type Event int
+
+const (
+	// Ignored are requests that haven been dropped by leaving the connection
+	// hanging to mitigate attacks. Inspect the reason for more information.
+	Ignored Event = iota
+
+	// Request is emitted for every accepted request. For every request event
+	// a finish event fill follow. You can inspect the message to see the
+	// complete request sent by the client.
+	Request Event = iota
+
+	// Refused are requests that received an error due to some incompatibility.
+	// Inspect the reason for more information.
+	Refused Event = iota
+
+	// BackendError is emitted with errors returned by the callback and
+	// validation functions. Inspect the error for more information.
+	BackendError Event = iota
+
+	// NetworkError is emitted with errors returned by the connection. Inspect
+	// the error for more information.
+	NetworkError Event = iota
+
+	// Response is emitted with the final response to the client. You can inspect
+	// the message to see the complete response to the client.
+	Response Event = iota
+
+	// Finish is emitted when a request has been processed.
+	Finish Event = iota
+
+	// ProxyRequest is emitted with every request forwarded to the fallback
+	// DNS server.
+	ProxyRequest Event = iota
+
+	// ProxyResponse is emitted with ever response received from the fallback
+	// DNS server.
+	ProxyResponse Event = iota
+
+	// ProxyError is emitted with errors returned by the fallback DNS server.
+	// Inspect the error for more information.
+	ProxyError Event = iota
+)
+
+// String will return the name of the event.
+func (e Event) String() string {
+	switch e {
+	case Ignored:
+		return "Ignored"
+	case Request:
+		return "Request"
+	case Refused:
+		return "Refused"
+	case BackendError:
+		return "BackendError"
+	case NetworkError:
+		return "NetworkError"
+	case Response:
+		return "Response"
+	case Finish:
+		return "Finish"
+	case ProxyRequest:
+		return "ProxyRequest"
+	case ProxyResponse:
+		return "ProxyResponse"
+	case ProxyError:
+		return "ProxyError"
+	default:
+		return "Unknown"
+	}
+}
+
+// Logger is function that accepts logging events.
+type Logger func(e Event, msg *dns.Msg, err error, reason string)
+
+func log(l Logger, e Event, msg *dns.Msg, err error, reason string) {
+	if l != nil {
+		l(e, msg, err, reason)
+	}
+}