it helps to add new files

src/yggdrasil/version.go

@@ -0,0 +1,70 @@
+package yggdrasil
+
+// This file contains the version metadata struct
+// Used in the inital connection setup and key exchange
+// Some of this could arguably go in wire.go instead
+
+type version_metadata struct {
+	meta [4]byte
+	ver  uint64 // 1 byte in this version
+	// Everything after this point potentially depends on the version number, and is subject to change in future versions
+	minorVer uint64 // 1 byte in this version
+	box      boxPubKey
+	sig      sigPubKey
+	link     boxPubKey
+}
+
+func version_getBaseMetadata() version_metadata {
+	return version_metadata{
+		meta:     [4]byte{'m', 'e', 't', 'a'},
+		ver:      0,
+		minorVer: 2,
+	}
+}
+
+func version_getMetaLength() (mlen int) {
+	mlen += 4            // meta
+	mlen += 1            // ver
+	mlen += 1            // minorVer
+	mlen += boxPubKeyLen // box
+	mlen += sigPubKeyLen // sig
+	mlen += boxPubKeyLen // link
+	return
+}
+
+func (m *version_metadata) encode() []byte {
+	bs := make([]byte, 0, version_getMetaLength())
+	bs = append(bs, m.meta[:]...)
+	bs = append(bs, wire_encode_uint64(m.ver)...)
+	bs = append(bs, wire_encode_uint64(m.minorVer)...)
+	bs = append(bs, m.box[:]...)
+	bs = append(bs, m.sig[:]...)
+	bs = append(bs, m.link[:]...)
+	if len(bs) != version_getMetaLength() {
+		panic("Inconsistent metadata length")
+	}
+	return bs
+}
+
+func (m *version_metadata) decode(bs []byte) bool {
+	switch {
+	case !wire_chop_slice(m.meta[:], &bs):
+		return false
+	case !wire_chop_uint64(&m.ver, &bs):
+		return false
+	case !wire_chop_uint64(&m.minorVer, &bs):
+		return false
+	case !wire_chop_slice(m.box[:], &bs):
+		return false
+	case !wire_chop_slice(m.sig[:], &bs):
+		return false
+	case !wire_chop_slice(m.link[:], &bs):
+		return false
+	}
+	return true
+}
+
+func (m *version_metadata) check() bool {
+	base := version_getBaseMetadata()
+	return base.meta == m.meta && base.ver == m.ver && base.minorVer == m.minorVer
+}