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111 lines
2.9 KiB
Go
111 lines
2.9 KiB
Go
package core
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// This file contains the version metadata struct
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// Used in the initial connection setup and key exchange
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// Some of this could arguably go in wire.go instead
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import (
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"bytes"
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"crypto/ed25519"
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"encoding/binary"
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)
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// This is the version-specific metadata exchanged at the start of a connection.
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// It must always begin with the 4 bytes "meta" and a wire formatted uint64 major version number.
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// The current version also includes a minor version number, and the box/sig/link keys that need to be exchanged to open a connection.
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type version_metadata struct {
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majorVer uint16
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minorVer uint16
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publicKey ed25519.PublicKey
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priority uint8
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}
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const (
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ProtocolVersionMajor uint16 = 0
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ProtocolVersionMinor uint16 = 5
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)
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const (
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metaVersionMajor uint16 = iota // uint16
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metaVersionMinor // uint16
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metaPublicKey // [32]byte
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metaPriority // uint8
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)
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// Gets a base metadata with no keys set, but with the correct version numbers.
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func version_getBaseMetadata() version_metadata {
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return version_metadata{
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majorVer: ProtocolVersionMajor,
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minorVer: ProtocolVersionMinor,
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}
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}
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// Encodes version metadata into its wire format.
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func (m *version_metadata) encode() []byte {
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bs := make([]byte, 0, 64)
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bs = append(bs, 'm', 'e', 't', 'a')
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bs = binary.BigEndian.AppendUint16(bs, metaVersionMajor)
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bs = binary.BigEndian.AppendUint16(bs, 2)
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bs = binary.BigEndian.AppendUint16(bs, m.majorVer)
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bs = binary.BigEndian.AppendUint16(bs, metaVersionMinor)
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bs = binary.BigEndian.AppendUint16(bs, 2)
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bs = binary.BigEndian.AppendUint16(bs, m.minorVer)
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bs = binary.BigEndian.AppendUint16(bs, metaPublicKey)
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bs = binary.BigEndian.AppendUint16(bs, ed25519.PublicKeySize)
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bs = append(bs, m.publicKey[:]...)
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bs = binary.BigEndian.AppendUint16(bs, metaPriority)
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bs = binary.BigEndian.AppendUint16(bs, 1)
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bs = append(bs, m.priority)
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return bs
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}
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// Decodes version metadata from its wire format into the struct.
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func (m *version_metadata) decode(bs []byte) bool {
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meta := [4]byte{'m', 'e', 't', 'a'}
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if !bytes.Equal(bs[:4], meta[:]) {
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return false
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}
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for bs = bs[4:]; len(bs) >= 4; {
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op := binary.BigEndian.Uint16(bs[:2])
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oplen := binary.BigEndian.Uint16(bs[2:4])
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if bs = bs[4:]; len(bs) < int(oplen) {
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break
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}
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switch op {
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case metaVersionMajor:
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m.majorVer = binary.BigEndian.Uint16(bs[:2])
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case metaVersionMinor:
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m.minorVer = binary.BigEndian.Uint16(bs[:2])
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case metaPublicKey:
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m.publicKey = make(ed25519.PublicKey, ed25519.PublicKeySize)
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copy(m.publicKey, bs[:ed25519.PublicKeySize])
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case metaPriority:
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m.priority = bs[0]
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}
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bs = bs[oplen:]
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}
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return true
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}
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// Checks that the "meta" bytes and the version numbers are the expected values.
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func (m *version_metadata) check() bool {
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switch {
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case m.majorVer != ProtocolVersionMajor:
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return false
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case m.minorVer != ProtocolVersionMinor:
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return false
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case len(m.publicKey) != ed25519.PublicKeySize:
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return false
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default:
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return true
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}
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}
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