move parsing of extended headers to the same file as the struct

internal/wire/header.go

@@ -0,0 +1,114 @@
+package wire
+
+import (
+	"bytes"
+	"io"
+
+	"github.com/lucas-clemente/quic-go/internal/protocol"
+	"github.com/lucas-clemente/quic-go/internal/qerr"
+	"github.com/lucas-clemente/quic-go/internal/utils"
+)
+
+// The Header is the version independent part of the header
+type Header struct {
+	Version          protocol.VersionNumber
+	SrcConnectionID  protocol.ConnectionID
+	DestConnectionID protocol.ConnectionID
+
+	SupportedVersions []protocol.VersionNumber // sent in a Version Negotiation Packet
+
+	typeByte byte
+	len      int // how many bytes were read while parsing this header
+}
+
+// ParseHeader parses the version independent part of the header
+func ParseHeader(b *bytes.Reader, shortHeaderConnIDLen int) (*Header, error) {
+	startLen := b.Len()
+	h, err := parseHeaderImpl(b, shortHeaderConnIDLen)
+	if err != nil {
+		return nil, err
+	}
+	h.len = startLen - b.Len()
+	return h, nil
+}
+
+func parseHeaderImpl(b *bytes.Reader, shortHeaderConnIDLen int) (*Header, error) {
+	typeByte, err := b.ReadByte()
+	if err != nil {
+		return nil, err
+	}
+
+	h := &Header{typeByte: typeByte}
+
+	// If this is not a Long Header, it could either be a Public Header or a Short Header.
+	if !h.IsLongHeader() {
+		var err error
+		h.DestConnectionID, err = protocol.ReadConnectionID(b, shortHeaderConnIDLen)
+		if err != nil {
+			return nil, err
+		}
+		return h, nil
+	}
+	// Long Header
+	v, err := utils.BigEndian.ReadUint32(b)
+	if err != nil {
+		return nil, err
+	}
+	h.Version = protocol.VersionNumber(v)
+	connIDLenByte, err := b.ReadByte()
+	if err != nil {
+		return nil, err
+	}
+	dcil, scil := decodeConnIDLen(connIDLenByte)
+	h.DestConnectionID, err = protocol.ReadConnectionID(b, dcil)
+	if err != nil {
+		return nil, err
+	}
+	h.SrcConnectionID, err = protocol.ReadConnectionID(b, scil)
+	if err != nil {
+		return nil, err
+	}
+	if h.Version == 0 {
+		if b.Len() == 0 {
+			return nil, qerr.Error(qerr.InvalidVersionNegotiationPacket, "empty version list")
+		}
+		h.SupportedVersions = make([]protocol.VersionNumber, b.Len()/4)
+		for i := 0; b.Len() > 0; i++ {
+			v, err := utils.BigEndian.ReadUint32(b)
+			if err != nil {
+				return nil, qerr.InvalidVersionNegotiationPacket
+			}
+			h.SupportedVersions[i] = protocol.VersionNumber(v)
+		}
+	}
+	return h, nil
+}
+
+// IsLongHeader says if this is a long header
+func (h *Header) IsLongHeader() bool {
+	return h.typeByte&0x80 > 0
+}
+
+// IsVersionNegotiation says if this a version negotiation packet
+func (h *Header) IsVersionNegotiation() bool {
+	return h.IsLongHeader() && h.Version == 0
+}
+
+// ParseExtended parses the version dependent part of the header.
+// The Reader has to be set such that it points to the first byte of the header.
+func (h *Header) ParseExtended(b *bytes.Reader, ver protocol.VersionNumber) (*ExtendedHeader, error) {
+	if _, err := b.Seek(int64(h.len), io.SeekCurrent); err != nil {
+		return nil, err
+	}
+	return h.toExtendedHeader().parse(b, ver)
+}
+
+func (h *Header) toExtendedHeader() *ExtendedHeader {
+	return &ExtendedHeader{
+		IsLongHeader:     h.IsLongHeader(),
+		typeByte:         h.typeByte,
+		DestConnectionID: h.DestConnectionID,
+		SrcConnectionID:  h.SrcConnectionID,
+		Version:          h.Version,
+	}
+}