101 lines
2.5 KiB
Go
101 lines
2.5 KiB
Go
package packets
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import (
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"bufio"
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"fmt"
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"io"
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"badat.dev/maeqtt/v2/mqtt/types"
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)
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type PacketVisitor interface {
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VisitConnect(ConnectPacket)
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VisitPublish(PublishPacket)
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VisitDisconnect(DisconnectPacket)
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VisitSubscribe(SubscribePacket)
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VisitUnsubscribe(UnsubscribePacket)
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VisitPing(PingreqPacket)
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VisitPubackPacket(PubackPacket)
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VisitPubrecPacket(PubrecPacket)
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VisitPubrelPacket(PubrelPacket)
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VisitPubcompPacket(PubcompPacket)
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}
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type ClientPacket interface {
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Visit(PacketVisitor)
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}
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type ServerPacket interface {
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Write(w io.Writer) error
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}
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type PacketType byte
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const (
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PacketTypeReserved PacketType = 0 // Forbidden
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PacketTypeConnect = 1
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PacketTypeConnack = 2
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PacketTypePublish = 3
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PacketTypePuback = 4
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PacketTypePubrec = 5
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PacketTypePubrel = 6
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PacketTypePubcomp = 7
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PacketTypeSubscribe = 8
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PacketTypeSuback = 9
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PacketTypeUnsubscribe = 10
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PacketTypeUnsuback = 11
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PacketTypePingreq = 12
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PacketTypePingresp = 13
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PacketTypeDisconnect = 14
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PacketTypeAuth = 15
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)
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func ReadPacket(r *bufio.Reader) (*ClientPacket, error) {
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fixedHeader, err := r.ReadByte()
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if err != nil {
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return nil, err
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}
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highestFourBits := uint((fixedHeader >> 4) & 0b1111)
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lowerFourBits := uint(fixedHeader & 0b1111)
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dataLength, err := types.DecodeVariableByteInt(r)
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if err != nil {
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return nil, err
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}
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reader := io.LimitReader(r, int64(dataLength))
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control := controlPacket{
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packetType: PacketType(highestFourBits),
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flags: lowerFourBits,
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reader: reader,
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}
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var packet ClientPacket
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switch control.packetType {
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case PacketTypeConnect:
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packet, err = parseConnectPacket(control)
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case PacketTypePublish:
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packet, err = parsePublishPacket(control)
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case PacketTypeDisconnect:
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packet, err = parseDisconnectPacket(control)
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case PacketTypeSubscribe:
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packet, err = parseSubscribePacket(control)
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case PacketTypeUnsubscribe:
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packet, err = parseUnsubscribePacket(control)
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case PacketTypePingreq:
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packet, err = parsePingreq(control)
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case PacketTypePuback:
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panic("Puback packet parsing unimplemented")
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case PacketTypePubrec:
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panic("Pubrec packet parsing unimplemented")
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case PacketTypePubrel:
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panic("Pubrel packet parsing unimplemented")
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case PacketTypePubcomp:
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panic("Pubcomp packet parsing unimplemented")
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default:
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return nil, fmt.Errorf("Unknown packet type %v", control.packetType)
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}
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return &packet, err
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}
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