fix parsing of the PublicHeader of public reset packets

ref #34

public_header.go

@@ -138,23 +138,25 @@ func ParsePublicHeader(b io.ByteReader) (*PublicHeader, error) {
 		return nil, errInvalidConnectionID
 	}
 
-	// Version (optional)
-	if header.VersionFlag {
-		var versionTag uint32
-		versionTag, err = utils.ReadUint32(b)
+	if !header.ResetFlag {
+		// Version (optional)
+		if header.VersionFlag {
+			var versionTag uint32
+			versionTag, err = utils.ReadUint32(b)
+			if err != nil {
+				return nil, err
+			}
+			header.VersionNumber = protocol.VersionTagToNumber(versionTag)
+		}
+
+		// Packet number
+		packetNumber, err := utils.ReadUintN(b, uint8(header.PacketNumberLen))
 		if err != nil {
 			return nil, err
 		}
-		header.VersionNumber = protocol.VersionTagToNumber(versionTag)
+		header.PacketNumber = protocol.PacketNumber(packetNumber)
 	}
 
-	// Packet number
-	packetNumber, err := utils.ReadUintN(b, uint8(header.PacketNumberLen))
-	if err != nil {
-		return nil, err
-	}
-	header.PacketNumber = protocol.PacketNumber(packetNumber)
-
 	return header, nil
 }
 

public_header_test.go

@@ -66,6 +66,16 @@ var _ = Describe("Public Header", func() {
 			Expect(b.Len()).To(BeZero())
 		})
 
+		It("parses a public reset packet", func() {
+			b := bytes.NewReader([]byte{0xa, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08})
+			hdr, err := ParsePublicHeader(b)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(hdr.ResetFlag).To(BeTrue())
+			Expect(hdr.VersionFlag).To(BeFalse())
+			Expect(hdr.ConnectionID).To(Equal(protocol.ConnectionID(0x0807060504030201)))
+			Expect(b.Len()).To(BeZero())
+		})
+
 		PIt("rejects diversification nonces sent by the client", func() {
 			b := bytes.NewReader([]byte{0x0c, 0xf6, 0x19, 0x86, 0x66, 0x9b, 0x9f, 0xfa, 0x4c,
 				0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1,