summaryrefslogtreecommitdiff
path: root/vendor/github.com/eclipse/paho.mqtt.golang/packets/packets.go
diff options
context:
space:
mode:
Diffstat (limited to 'vendor/github.com/eclipse/paho.mqtt.golang/packets/packets.go')
-rw-r--r--vendor/github.com/eclipse/paho.mqtt.golang/packets/packets.go377
1 files changed, 377 insertions, 0 deletions
diff --git a/vendor/github.com/eclipse/paho.mqtt.golang/packets/packets.go b/vendor/github.com/eclipse/paho.mqtt.golang/packets/packets.go
new file mode 100644
index 0000000..7cc3c6d
--- /dev/null
+++ b/vendor/github.com/eclipse/paho.mqtt.golang/packets/packets.go
@@ -0,0 +1,377 @@
+/*
+ * Copyright (c) 2021 IBM Corp and others.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v2.0
+ * and Eclipse Distribution License v1.0 which accompany this distribution.
+ *
+ * The Eclipse Public License is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ * and the Eclipse Distribution License is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * Contributors:
+ * Allan Stockdill-Mander
+ */
+
+package packets
+
+import (
+ "bytes"
+ "encoding/binary"
+ "errors"
+ "fmt"
+ "io"
+)
+
+// ControlPacket defines the interface for structs intended to hold
+// decoded MQTT packets, either from being read or before being
+// written
+type ControlPacket interface {
+ Write(io.Writer) error
+ Unpack(io.Reader) error
+ String() string
+ Details() Details
+}
+
+// PacketNames maps the constants for each of the MQTT packet types
+// to a string representation of their name.
+var PacketNames = map[uint8]string{
+ 1: "CONNECT",
+ 2: "CONNACK",
+ 3: "PUBLISH",
+ 4: "PUBACK",
+ 5: "PUBREC",
+ 6: "PUBREL",
+ 7: "PUBCOMP",
+ 8: "SUBSCRIBE",
+ 9: "SUBACK",
+ 10: "UNSUBSCRIBE",
+ 11: "UNSUBACK",
+ 12: "PINGREQ",
+ 13: "PINGRESP",
+ 14: "DISCONNECT",
+}
+
+// Below are the constants assigned to each of the MQTT packet types
+const (
+ Connect = 1
+ Connack = 2
+ Publish = 3
+ Puback = 4
+ Pubrec = 5
+ Pubrel = 6
+ Pubcomp = 7
+ Subscribe = 8
+ Suback = 9
+ Unsubscribe = 10
+ Unsuback = 11
+ Pingreq = 12
+ Pingresp = 13
+ Disconnect = 14
+)
+
+// Below are the const definitions for error codes returned by
+// Connect()
+const (
+ Accepted = 0x00
+ ErrRefusedBadProtocolVersion = 0x01
+ ErrRefusedIDRejected = 0x02
+ ErrRefusedServerUnavailable = 0x03
+ ErrRefusedBadUsernameOrPassword = 0x04
+ ErrRefusedNotAuthorised = 0x05
+ ErrNetworkError = 0xFE
+ ErrProtocolViolation = 0xFF
+)
+
+// ConnackReturnCodes is a map of the error codes constants for Connect()
+// to a string representation of the error
+var ConnackReturnCodes = map[uint8]string{
+ 0: "Connection Accepted",
+ 1: "Connection Refused: Bad Protocol Version",
+ 2: "Connection Refused: Client Identifier Rejected",
+ 3: "Connection Refused: Server Unavailable",
+ 4: "Connection Refused: Username or Password in unknown format",
+ 5: "Connection Refused: Not Authorised",
+ 254: "Connection Error",
+ 255: "Connection Refused: Protocol Violation",
+}
+
+var (
+ ErrorRefusedBadProtocolVersion = errors.New("unacceptable protocol version")
+ ErrorRefusedIDRejected = errors.New("identifier rejected")
+ ErrorRefusedServerUnavailable = errors.New("server Unavailable")
+ ErrorRefusedBadUsernameOrPassword = errors.New("bad user name or password")
+ ErrorRefusedNotAuthorised = errors.New("not Authorized")
+ ErrorNetworkError = errors.New("network Error")
+ ErrorProtocolViolation = errors.New("protocol Violation")
+)
+
+// ConnErrors is a map of the errors codes constants for Connect()
+// to a Go error
+var ConnErrors = map[byte]error{
+ Accepted: nil,
+ ErrRefusedBadProtocolVersion: ErrorRefusedBadProtocolVersion,
+ ErrRefusedIDRejected: ErrorRefusedIDRejected,
+ ErrRefusedServerUnavailable: ErrorRefusedServerUnavailable,
+ ErrRefusedBadUsernameOrPassword: ErrorRefusedBadUsernameOrPassword,
+ ErrRefusedNotAuthorised: ErrorRefusedNotAuthorised,
+ ErrNetworkError: ErrorNetworkError,
+ ErrProtocolViolation: ErrorProtocolViolation,
+}
+
+// ReadPacket takes an instance of an io.Reader (such as net.Conn) and attempts
+// to read an MQTT packet from the stream. It returns a ControlPacket
+// representing the decoded MQTT packet and an error. One of these returns will
+// always be nil, a nil ControlPacket indicating an error occurred.
+func ReadPacket(r io.Reader) (ControlPacket, error) {
+ var fh FixedHeader
+ b := make([]byte, 1)
+
+ _, err := io.ReadFull(r, b)
+ if err != nil {
+ return nil, err
+ }
+
+ err = fh.unpack(b[0], r)
+ if err != nil {
+ return nil, err
+ }
+
+ cp, err := NewControlPacketWithHeader(fh)
+ if err != nil {
+ return nil, err
+ }
+
+ packetBytes := make([]byte, fh.RemainingLength)
+ n, err := io.ReadFull(r, packetBytes)
+ if err != nil {
+ return nil, err
+ }
+ if n != fh.RemainingLength {
+ return nil, errors.New("failed to read expected data")
+ }
+
+ err = cp.Unpack(bytes.NewBuffer(packetBytes))
+ return cp, err
+}
+
+// NewControlPacket is used to create a new ControlPacket of the type specified
+// by packetType, this is usually done by reference to the packet type constants
+// defined in packets.go. The newly created ControlPacket is empty and a pointer
+// is returned.
+func NewControlPacket(packetType byte) ControlPacket {
+ switch packetType {
+ case Connect:
+ return &ConnectPacket{FixedHeader: FixedHeader{MessageType: Connect}}
+ case Connack:
+ return &ConnackPacket{FixedHeader: FixedHeader{MessageType: Connack}}
+ case Disconnect:
+ return &DisconnectPacket{FixedHeader: FixedHeader{MessageType: Disconnect}}
+ case Publish:
+ return &PublishPacket{FixedHeader: FixedHeader{MessageType: Publish}}
+ case Puback:
+ return &PubackPacket{FixedHeader: FixedHeader{MessageType: Puback}}
+ case Pubrec:
+ return &PubrecPacket{FixedHeader: FixedHeader{MessageType: Pubrec}}
+ case Pubrel:
+ return &PubrelPacket{FixedHeader: FixedHeader{MessageType: Pubrel, Qos: 1}}
+ case Pubcomp:
+ return &PubcompPacket{FixedHeader: FixedHeader{MessageType: Pubcomp}}
+ case Subscribe:
+ return &SubscribePacket{FixedHeader: FixedHeader{MessageType: Subscribe, Qos: 1}}
+ case Suback:
+ return &SubackPacket{FixedHeader: FixedHeader{MessageType: Suback}}
+ case Unsubscribe:
+ return &UnsubscribePacket{FixedHeader: FixedHeader{MessageType: Unsubscribe, Qos: 1}}
+ case Unsuback:
+ return &UnsubackPacket{FixedHeader: FixedHeader{MessageType: Unsuback}}
+ case Pingreq:
+ return &PingreqPacket{FixedHeader: FixedHeader{MessageType: Pingreq}}
+ case Pingresp:
+ return &PingrespPacket{FixedHeader: FixedHeader{MessageType: Pingresp}}
+ }
+ return nil
+}
+
+// NewControlPacketWithHeader is used to create a new ControlPacket of the type
+// specified within the FixedHeader that is passed to the function.
+// The newly created ControlPacket is empty and a pointer is returned.
+func NewControlPacketWithHeader(fh FixedHeader) (ControlPacket, error) {
+ switch fh.MessageType {
+ case Connect:
+ return &ConnectPacket{FixedHeader: fh}, nil
+ case Connack:
+ return &ConnackPacket{FixedHeader: fh}, nil
+ case Disconnect:
+ return &DisconnectPacket{FixedHeader: fh}, nil
+ case Publish:
+ return &PublishPacket{FixedHeader: fh}, nil
+ case Puback:
+ return &PubackPacket{FixedHeader: fh}, nil
+ case Pubrec:
+ return &PubrecPacket{FixedHeader: fh}, nil
+ case Pubrel:
+ return &PubrelPacket{FixedHeader: fh}, nil
+ case Pubcomp:
+ return &PubcompPacket{FixedHeader: fh}, nil
+ case Subscribe:
+ return &SubscribePacket{FixedHeader: fh}, nil
+ case Suback:
+ return &SubackPacket{FixedHeader: fh}, nil
+ case Unsubscribe:
+ return &UnsubscribePacket{FixedHeader: fh}, nil
+ case Unsuback:
+ return &UnsubackPacket{FixedHeader: fh}, nil
+ case Pingreq:
+ return &PingreqPacket{FixedHeader: fh}, nil
+ case Pingresp:
+ return &PingrespPacket{FixedHeader: fh}, nil
+ }
+ return nil, fmt.Errorf("unsupported packet type 0x%x", fh.MessageType)
+}
+
+// Details struct returned by the Details() function called on
+// ControlPackets to present details of the Qos and MessageID
+// of the ControlPacket
+type Details struct {
+ Qos byte
+ MessageID uint16
+}
+
+// FixedHeader is a struct to hold the decoded information from
+// the fixed header of an MQTT ControlPacket
+type FixedHeader struct {
+ MessageType byte
+ Dup bool
+ Qos byte
+ Retain bool
+ RemainingLength int
+}
+
+func (fh FixedHeader) String() string {
+ return fmt.Sprintf("%s: dup: %t qos: %d retain: %t rLength: %d", PacketNames[fh.MessageType], fh.Dup, fh.Qos, fh.Retain, fh.RemainingLength)
+}
+
+func boolToByte(b bool) byte {
+ switch b {
+ case true:
+ return 1
+ default:
+ return 0
+ }
+}
+
+func (fh *FixedHeader) pack() bytes.Buffer {
+ var header bytes.Buffer
+ header.WriteByte(fh.MessageType<<4 | boolToByte(fh.Dup)<<3 | fh.Qos<<1 | boolToByte(fh.Retain))
+ header.Write(encodeLength(fh.RemainingLength))
+ return header
+}
+
+func (fh *FixedHeader) unpack(typeAndFlags byte, r io.Reader) error {
+ fh.MessageType = typeAndFlags >> 4
+ fh.Dup = (typeAndFlags>>3)&0x01 > 0
+ fh.Qos = (typeAndFlags >> 1) & 0x03
+ fh.Retain = typeAndFlags&0x01 > 0
+
+ var err error
+ fh.RemainingLength, err = decodeLength(r)
+ return err
+}
+
+func decodeByte(b io.Reader) (byte, error) {
+ num := make([]byte, 1)
+ _, err := b.Read(num)
+ if err != nil {
+ return 0, err
+ }
+
+ return num[0], nil
+}
+
+func decodeUint16(b io.Reader) (uint16, error) {
+ num := make([]byte, 2)
+ _, err := b.Read(num)
+ if err != nil {
+ return 0, err
+ }
+ return binary.BigEndian.Uint16(num), nil
+}
+
+func encodeUint16(num uint16) []byte {
+ bytesResult := make([]byte, 2)
+ binary.BigEndian.PutUint16(bytesResult, num)
+ return bytesResult
+}
+
+func encodeString(field string) []byte {
+ return encodeBytes([]byte(field))
+}
+
+func decodeString(b io.Reader) (string, error) {
+ buf, err := decodeBytes(b)
+ return string(buf), err
+}
+
+func decodeBytes(b io.Reader) ([]byte, error) {
+ fieldLength, err := decodeUint16(b)
+ if err != nil {
+ return nil, err
+ }
+
+ field := make([]byte, fieldLength)
+ _, err = b.Read(field)
+ if err != nil {
+ return nil, err
+ }
+
+ return field, nil
+}
+
+func encodeBytes(field []byte) []byte {
+ // Attempting to encode more than 65,535 bytes would lead to an unexpected 16-bit length and extra data written
+ // (which would be parsed as later parts of the message). The safest option is to truncate.
+ if len(field) > 65535 {
+ field = field[0:65535]
+ }
+ fieldLength := make([]byte, 2)
+ binary.BigEndian.PutUint16(fieldLength, uint16(len(field)))
+ return append(fieldLength, field...)
+}
+
+func encodeLength(length int) []byte {
+ var encLength []byte
+ for {
+ digit := byte(length % 128)
+ length /= 128
+ if length > 0 {
+ digit |= 0x80
+ }
+ encLength = append(encLength, digit)
+ if length == 0 {
+ break
+ }
+ }
+ return encLength
+}
+
+func decodeLength(r io.Reader) (int, error) {
+ var rLength uint32
+ var multiplier uint32
+ b := make([]byte, 1)
+ for multiplier < 27 { // fix: Infinite '(digit & 128) == 1' will cause the dead loop
+ _, err := io.ReadFull(r, b)
+ if err != nil {
+ return 0, err
+ }
+
+ digit := b[0]
+ rLength |= uint32(digit&127) << multiplier
+ if (digit & 128) == 0 {
+ break
+ }
+ multiplier += 7
+ }
+ return int(rLength), nil
+}
generated by cgit v1.2.3-70-g09d2 (git 2.52.0) at 2025-12-22 12:42:42 +0000