129 lines
3.8 KiB
Go
129 lines
3.8 KiB
Go
package packets
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import (
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"bytes"
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"fmt"
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"github.com/pborman/uuid"
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"io"
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)
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//ConnectPacket is an internal representation of the fields of the
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//Connect MQTT packet
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type ConnectPacket struct {
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FixedHeader
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ProtocolName string
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ProtocolVersion byte
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CleanSession bool
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WillFlag bool
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WillQos byte
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WillRetain bool
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UsernameFlag bool
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PasswordFlag bool
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ReservedBit byte
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KeepaliveTimer uint16
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ClientIdentifier string
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WillTopic string
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WillMessage []byte
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Username string
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Password []byte
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uuid uuid.UUID
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}
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func (c *ConnectPacket) String() string {
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str := fmt.Sprintf("%s\n", c.FixedHeader)
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str += fmt.Sprintf("protocolversion: %d protocolname: %s cleansession: %t willflag: %t WillQos: %d WillRetain: %t Usernameflag: %t Passwordflag: %t keepalivetimer: %d\nclientId: %s\nwilltopic: %s\nwillmessage: %s\nUsername: %s\nPassword: %s\n", c.ProtocolVersion, c.ProtocolName, c.CleanSession, c.WillFlag, c.WillQos, c.WillRetain, c.UsernameFlag, c.PasswordFlag, c.KeepaliveTimer, c.ClientIdentifier, c.WillTopic, c.WillMessage, c.Username, c.Password)
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return str
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}
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func (c *ConnectPacket) Write(w io.Writer) error {
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var body bytes.Buffer
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var err error
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body.Write(encodeString(c.ProtocolName))
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body.WriteByte(c.ProtocolVersion)
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body.WriteByte(boolToByte(c.CleanSession)<<1 | boolToByte(c.WillFlag)<<2 | c.WillQos<<3 | boolToByte(c.WillRetain)<<5 | boolToByte(c.PasswordFlag)<<6 | boolToByte(c.UsernameFlag)<<7)
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body.Write(encodeUint16(c.KeepaliveTimer))
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body.Write(encodeString(c.ClientIdentifier))
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if c.WillFlag {
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body.Write(encodeString(c.WillTopic))
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body.Write(encodeBytes(c.WillMessage))
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}
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if c.UsernameFlag {
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body.Write(encodeString(c.Username))
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}
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if c.PasswordFlag {
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body.Write(encodeBytes(c.Password))
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}
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c.FixedHeader.RemainingLength = body.Len()
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packet := c.FixedHeader.pack()
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packet.Write(body.Bytes())
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_, err = packet.WriteTo(w)
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return err
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}
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//Unpack decodes the details of a ControlPacket after the fixed
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//header has been read
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func (c *ConnectPacket) Unpack(b io.Reader) {
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c.ProtocolName = decodeString(b)
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c.ProtocolVersion = decodeByte(b)
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options := decodeByte(b)
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c.ReservedBit = 1 & options
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c.CleanSession = 1&(options>>1) > 0
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c.WillFlag = 1&(options>>2) > 0
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c.WillQos = 3 & (options >> 3)
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c.WillRetain = 1&(options>>5) > 0
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c.PasswordFlag = 1&(options>>6) > 0
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c.UsernameFlag = 1&(options>>7) > 0
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c.KeepaliveTimer = decodeUint16(b)
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c.ClientIdentifier = decodeString(b)
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if c.WillFlag {
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c.WillTopic = decodeString(b)
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c.WillMessage = decodeBytes(b)
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}
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if c.UsernameFlag {
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c.Username = decodeString(b)
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}
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if c.PasswordFlag {
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c.Password = decodeBytes(b)
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}
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}
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//Validate performs validation of the fields of a Connect packet
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func (c *ConnectPacket) Validate() byte {
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if c.PasswordFlag && !c.UsernameFlag {
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return ErrRefusedBadUsernameOrPassword
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}
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if c.ReservedBit != 0 {
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//Bad reserved bit
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return ErrProtocolViolation
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}
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if (c.ProtocolName == "MQIsdp" && c.ProtocolVersion != 3) || (c.ProtocolName == "MQTT" && c.ProtocolVersion != 4) {
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//Mismatched or unsupported protocol version
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return ErrRefusedBadProtocolVersion
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}
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if c.ProtocolName != "MQIsdp" && c.ProtocolName != "MQTT" {
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//Bad protocol name
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return ErrProtocolViolation
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}
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if len(c.ClientIdentifier) > 65535 || len(c.Username) > 65535 || len(c.Password) > 65535 {
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//Bad size field
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return ErrProtocolViolation
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}
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return Accepted
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}
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//Details returns a Details struct containing the Qos and
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//MessageID of this ControlPacket
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func (c *ConnectPacket) Details() Details {
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return Details{Qos: 0, MessageID: 0}
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}
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//UUID returns the unique ID assigned to the ControlPacket when
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//it was originally received. Note: this is not related to the
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//MessageID field for MQTT packets
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func (c *ConnectPacket) UUID() uuid.UUID {
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return c.uuid
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}
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