115 lines
2.3 KiB
Go
115 lines
2.3 KiB
Go
package node
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import (
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"errors"
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"net/netip"
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)
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var (
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errMalformedPacket = errors.New("malformed packet")
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errUnknownPacketType = errors.New("unknown packet type")
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)
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const (
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packetTypeSyn = iota + 1
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packetTypeSynAck
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packetTypeAck
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)
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// ----------------------------------------------------------------------------
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type controlPacket struct {
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SrcIP byte
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RemoteAddr netip.AddrPort
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Payload any
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}
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func (p *controlPacket) ParsePayload(buf []byte) (err error) {
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switch buf[0] {
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case packetTypeSyn:
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p.Payload, err = parseSynPacket(buf)
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case packetTypeSynAck:
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p.Payload, err = parseSynAckPacket(buf)
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case packetTypeAck:
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p.Payload, err = parseAckPacket(buf)
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default:
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return errUnknownPacketType
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}
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return err
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}
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// ----------------------------------------------------------------------------
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type synPacket struct {
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TraceID uint64 // TraceID to match response w/ request.
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SharedKey [32]byte // Our shared key.
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RelayIP byte
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}
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func (p synPacket) Marshal(buf []byte) []byte {
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return newBinWriter(buf).
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Byte(packetTypeSyn).
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Uint64(p.TraceID).
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SharedKey(p.SharedKey).
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Byte(p.RelayIP).
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Build()
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}
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func parseSynPacket(buf []byte) (p synPacket, err error) {
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err = newBinReader(buf[1:]).
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Uint64(&p.TraceID).
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SharedKey(&p.SharedKey).
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Byte(&p.RelayIP).
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Error()
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return
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}
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// ----------------------------------------------------------------------------
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type synAckPacket struct {
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TraceID uint64
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RecvAddr netip.AddrPort
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}
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func (p synAckPacket) Marshal(buf []byte) []byte {
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return newBinWriter(buf).
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Byte(packetTypeSynAck).
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Uint64(p.TraceID).
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AddrPort(p.RecvAddr).
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Build()
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}
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func parseSynAckPacket(buf []byte) (p synAckPacket, err error) {
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err = newBinReader(buf[1:]).
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Uint64(&p.TraceID).
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AddrPort(&p.RecvAddr).
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Error()
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return
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}
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// ----------------------------------------------------------------------------
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type ackPacket struct {
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TraceID uint64
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SendAddr netip.AddrPort // Address of the sender.
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RecvAddr netip.AddrPort // Address of the recipient as seen by sender.
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}
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func (p ackPacket) Marshal(buf []byte) []byte {
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return newBinWriter(buf).
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Byte(packetTypeAck).
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Uint64(p.TraceID).
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AddrPort(p.SendAddr).
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AddrPort(p.RecvAddr).
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Build()
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}
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func parseAckPacket(buf []byte) (p ackPacket, err error) {
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err = newBinReader(buf[1:]).
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Uint64(&p.TraceID).
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AddrPort(&p.SendAddr).
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AddrPort(&p.RecvAddr).
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Error()
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return
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}
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