Close on unknown message type

protocol/protocol.go

@@ -4,6 +4,7 @@ import (
 	"compress/flate"
 	"errors"
 	"io"
+	"log"
 	"sync"
 	"time"
 
@@ -193,6 +194,7 @@ func (c *Connection) readerLoop() {
 			break
 		}
 		if hdr.version != 0 {
+			log.Printf("Protocol error: %s: unknown message version %#x", c.ID, hdr.version)
 			c.close()
 			break
 		}
@@ -258,6 +260,10 @@ func (c *Connection) readerLoop() {
 				delete(c.awaiting, hdr.msgID)
 				c.wLock.Unlock()
 			}
+
+		default:
+			log.Printf("Protocol error: %s: unknown message type %#x", c.ID, hdr.msgType)
+			c.close()
 		}
 	}
 }

protocol/protocol_test.go

@@ -157,3 +157,25 @@ func TestVersionErr(t *testing.T) {
 		t.Error("Connection should close due to unknown version")
 	}
 }
+
+func TestTypeErr(t *testing.T) {
+	m0 := &TestModel{}
+	m1 := &TestModel{}
+
+	ar, aw := io.Pipe()
+	br, bw := io.Pipe()
+
+	c0 := NewConnection("c0", ar, bw, m0)
+	NewConnection("c1", br, aw, m1)
+
+	c0.mwriter.writeHeader(header{
+		version: 0,
+		msgID:   0,
+		msgType: 42,
+	})
+	c0.flush()
+
+	if !m1.closed {
+		t.Error("Connection should close due to unknown message type")
+	}
+}