90 lines
2.0 KiB
Go
90 lines
2.0 KiB
Go
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package packets
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import (
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"bytes"
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"fmt"
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"io"
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"github.com/winc-link/hummingbird/internal/pkg/codes"
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)
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// Connack represents the MQTT Connack packet
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type Connack struct {
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Version Version
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FixHeader *FixHeader
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Code codes.Code
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SessionPresent bool
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Properties *Properties
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}
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func (c *Connack) String() string {
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return fmt.Sprintf("Connack, Version: %v, Code:%v, SessionPresent:%v, Properties: %s", c.Version, c.Code, c.SessionPresent, c.Properties)
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}
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// Pack encodes the packet struct into bytes and writes it into io.Writer.
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func (c *Connack) Pack(w io.Writer) error {
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var err error
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c.FixHeader = &FixHeader{PacketType: CONNACK, Flags: FlagReserved}
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bufw := &bytes.Buffer{}
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if c.SessionPresent {
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bufw.WriteByte(1)
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} else {
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bufw.WriteByte(0)
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}
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bufw.WriteByte(c.Code)
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if c.Version == Version5 {
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c.Properties.Pack(bufw, CONNACK)
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}
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c.FixHeader.RemainLength = bufw.Len()
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err = c.FixHeader.Pack(w)
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if err != nil {
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return err
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}
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_, err = bufw.WriteTo(w)
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return err
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}
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// Unpack read the packet bytes from io.Reader and decodes it into the packet struct
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func (c *Connack) Unpack(r io.Reader) error {
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restBuffer := make([]byte, c.FixHeader.RemainLength)
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_, err := io.ReadFull(r, restBuffer)
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if err != nil {
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return codes.ErrMalformed
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}
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bufr := bytes.NewBuffer(restBuffer)
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sp, err := bufr.ReadByte()
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if (127 & (sp >> 1)) > 0 {
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return codes.ErrMalformed
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}
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c.SessionPresent = sp == 1
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code, err := bufr.ReadByte()
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if err != nil {
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return codes.ErrMalformed
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}
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c.Code = code
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if c.Version == Version5 {
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if !ValidateCode(CONNACK, code) {
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return codes.ErrProtocol
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}
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c.Properties = &Properties{}
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return c.Properties.Unpack(bufr, CONNACK)
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}
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return nil
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}
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// NewConnackPacket returns a Connack instance by the given FixHeader and io.Reader
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func NewConnackPacket(fh *FixHeader, version Version, r io.Reader) (*Connack, error) {
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p := &Connack{FixHeader: fh, Version: Version5}
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if fh.Flags != FlagReserved {
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return nil, codes.ErrMalformed
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}
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err := p.Unpack(r)
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if err != nil {
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return nil, err
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}
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return p, err
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}
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