Initial import

protocol/detect_postgres.go

@@ -0,0 +1,70 @@
+package protocol
+
+import (
+	"encoding/binary"
+	"log"
+)
+
+func init() {
+	registerPostgreSQL()
+}
+
+func registerPostgreSQL() {
+	Register(Server, "R\x00???", detectPostgreSQLServer)             // Authentication request
+	Register(Server, "K\x00???", detectPostgreSQLServer)             // BackendKeyData
+	Register(Server, "S\x00???", detectPostgreSQLServer)             // ParameterStatus
+	Register(Server, "Z\x00???", detectPostgreSQLServer)             // ReadyForQuery
+	Register(Server, "E\x00???", detectPostgreSQLServer)             // ErrorResponse
+	Register(Server, "N\x00???", detectPostgreSQLServer)             // NoticeResponse
+	Register(Client, "????\x00\x02\x00\x00", detectPostgreSQLClient) // Startup packet, protocol 2.0
+	Register(Client, "????\x00\x03\x00\x00", detectPostgreSQLClient) // Startup packet, protocol 3.0
+}
+
+func detectPostgreSQLClient(dir Direction, data []byte) *Protocol {
+	// A client startup message needs at least 8 bytes (length + protocol version).
+	if len(data) < 8 {
+		return nil
+	}
+
+	length := int(binary.BigEndian.Uint32(data[0:]))
+	if len(data) != length {
+		log.Printf("not postgres %q: %d != %d", data, len(data), length)
+		return nil
+	}
+
+	major := int(binary.BigEndian.Uint16(data[4:]))
+	minor := int(binary.BigEndian.Uint16(data[6:]))
+	if major == 2 || major == 3 {
+		return &Protocol{
+			Name: ProtocolPostgreSQL,
+			Version: Version{
+				Major: major,
+				Minor: minor,
+				Patch: -1,
+			},
+		}
+	}
+	return nil
+}
+
+func detectPostgreSQLServer(dir Direction, data []byte) *Protocol {
+	// A server message needs at least 5 bytes (type + length).
+	if len(data) < 5 {
+		return nil
+	}
+
+	// All server messages (and subsequent client messages) are tagged with a single-byte type.
+	firstByte := data[0]
+	switch firstByte {
+	case 'R', // Authentication request
+		'K', // BackendKeyData
+		'S', // ParameterStatus
+		'Z', // ReadyForQuery
+		'E', // ErrorResponse
+		'N': // NoticeResponse
+		return &Protocol{Name: ProtocolPostgreSQL}
+
+	default:
+		return nil
+	}
+}