Refactoring to more easily adapt to multiple channels
Also adding chat message support.
This commit is contained in:
Sarah Jamie Lewis
parent
2d93acf065
commit
64d08bdff0
294
ricochet.go
294
ricochet.go
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@ -7,6 +7,7 @@ import (
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"crypto/sha256"
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"crypto/x509"
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"encoding/asn1"
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"encoding/binary"
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"encoding/pem"
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"errors"
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"fmt"
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@ -23,11 +24,40 @@ import (
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"strings"
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)
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// MessageType details the different kinds of messages used by Ricochet
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type MessageType int
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const (
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// CONTROL messages are those sent on channel 0
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CONTROL MessageType = iota
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// AUTH messages are those that deal with authentication
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AUTH = iota
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// DATA covers both chat and (later) file handling and other non-control messages.
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DATA = iota
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)
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// Ricochet is a protocol to conducting anonymous IM.
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type Ricochet struct {
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conn net.Conn
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privateKey *pem.Block
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logger *log.Logger
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channelState map[int]int
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channel chan RicochetMessage
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}
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// RicochetData is a structure containing the raw data and the channel it the
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// message originated on.
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type RicochetData struct {
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Channel int
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Data []byte
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}
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// RicochetMessage is a Wrapper Around Common Ricochet Protocol Strucutres
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type RicochetMessage struct {
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Channel int
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ControlPacket *Protocol_Data_Control.Packet
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DataPacket *Protocol_Data_Chat.Packet
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AuthPacket *Protocol_Data_AuthHiddenService.Packet
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}
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// Init sets up the Ricochet object. It takes in a filename of a hidden service
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@ -53,68 +83,8 @@ func (r *Ricochet) Init(filename string, debugLog bool) {
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}
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r.privateKey = block
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}
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func (r *Ricochet) send(data []byte) {
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fmt.Fprintf(r.conn, "%s", data)
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}
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func (r *Ricochet) recv() ([]byte, error) {
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buf := make([]byte, 4096)
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n, err := r.conn.Read(buf)
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r.logger.Print("Received Response From Service: ", n, err)
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if err != nil {
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return nil, err
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}
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ret := make([]byte, n)
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copy(ret[:], buf[:])
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return ret, nil
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}
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func (r *Ricochet) decodePacket(response []byte) *Protocol_Data_Control.Packet {
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// TODO: Check Length and Channel are Sane
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if len(response) < 4 {
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r.logger.Fatal("Response is too short ", response)
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return nil
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}
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res := new(Protocol_Data_Control.Packet)
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err := proto.Unmarshal(response[4:], res)
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if err != nil {
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r.logger.Fatal("Error Unmarshalling Response", err)
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}
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return res
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}
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func (r *Ricochet) decodeResult(response []byte) *Protocol_Data_AuthHiddenService.Packet {
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// TODO: Check Length and Channel are Sane
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if len(response) < 4 {
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r.logger.Fatal("Response is too short ", response)
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return nil
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}
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length := response[1]
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r.logger.Print(response)
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res := new(Protocol_Data_AuthHiddenService.Packet)
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err := proto.Unmarshal(response[4:length], res)
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if err != nil {
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r.logger.Fatal("Error Unmarshalling Response: ", err)
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}
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return res
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}
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func (r *Ricochet) constructProtocol(data []byte, channel int) []byte {
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header := make([]byte, 4+len(data))
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r.logger.Print("Wrting Packet of Size: ", len(header))
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header[0] = byte(len(header) >> 8)
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header[1] = byte(len(header) & 0x00FF)
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header[2] = 0x00
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header[3] = byte(channel)
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copy(header[4:], data[:])
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return header
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r.channelState = make(map[int]int)
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r.channel = make(chan RicochetMessage)
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}
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// Connect sets up a ricochet connection between from and to which are
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@ -172,10 +142,10 @@ func (r *Ricochet) Connect(from string, to string) error {
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r.logger.Print("Opening Channel: ", pc)
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r.send(openChannel)
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response, _ := r.recv()
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openChannelResponse := r.decodePacket(response)
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response, _ := r.getMessages()
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openChannelResponse, _ := r.decodePacket(response[0], CONTROL)
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r.logger.Print("Received Response: ", openChannelResponse)
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channelResult := openChannelResponse.GetChannelResult()
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channelResult := openChannelResponse.ControlPacket.GetChannelResult()
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if channelResult.GetOpened() == true {
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r.logger.Print("Channel Opened Successfully: ", channelResult.GetChannelIdentifier())
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@ -232,8 +202,8 @@ func (r *Ricochet) Connect(from string, to string) error {
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r.logger.Print("Constructed Proof: ", ahsPacket)
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r.send(sendProof)
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response, _ = r.recv()
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resultResponse := r.decodeResult(response)
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response, _ = r.getMessages()
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resultResponse, _ := r.decodePacket(response[0], AUTH)
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r.logger.Print("Received Result: ", resultResponse)
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return nil
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}
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@ -257,18 +227,8 @@ func (r *Ricochet) OpenChannel(channelType string, id int) error {
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openChannel := r.constructProtocol(data, 0)
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r.logger.Print("Opening Channel: ", pc)
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r.send(openChannel)
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response, _ := r.recv()
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openChannelResponse := r.decodePacket(response)
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r.logger.Print("Received Response: ", openChannelResponse)
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channelResult := openChannelResponse.GetChannelResult()
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if channelResult.GetOpened() == true {
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r.logger.Print("Channel Opened Successfully: ", channelResult.GetChannelIdentifier())
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return nil
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}
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return errors.New("failed to open channel")
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}
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// SendContactRequest initiates a contact request to the server.
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// Prerequisites:
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@ -298,9 +258,6 @@ func (r *Ricochet) SendContactRequest(nick string, message string) {
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openChannel := r.constructProtocol(data, 0)
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r.logger.Print("Opening Channel: ", pc)
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r.send(openChannel)
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response, _ := r.recv()
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openChannelResponse := r.decodePacket(response)
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r.logger.Print("Received Response: ", openChannelResponse)
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}
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// SendMessage sends a Chat Message (message) to a give Channel (channel).
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@ -343,3 +300,180 @@ func (r *Ricochet) negotiateVersion() {
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r.logger.Print("Successfully Negotiated Version ", res[0])
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}
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// constructProtocol places the data into a structure needed for the client to
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// decode the packet.
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func (r *Ricochet) constructProtocol(data []byte, channel int) []byte {
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header := make([]byte, 4+len(data))
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r.logger.Print("Wrting Packet of Size: ", len(header))
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header[0] = byte(len(header) >> 8)
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header[1] = byte(len(header) & 0x00FF)
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header[2] = 0x00
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header[3] = byte(channel)
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copy(header[4:], data[:])
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return header
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}
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// send is a utility funtion to send data to the connected client.
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func (r *Ricochet) send(data []byte) {
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fmt.Fprintf(r.conn, "%s", data)
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}
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// Listen blocks and waits for a new message to arrive from the connected user
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// once a message has arrived, it returns the message and the channel it occured
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// on, else it returns an error.
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// Prerequisites:
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// * Must have previously issued a successful Connect()
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// * Must have previously ran "go ricochet.ListenAndWait()"
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func (r *Ricochet) Listen() (string, int, error) {
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var message RicochetMessage
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message = <-r.channel
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r.logger.Print("Received Result: ", message)
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if message.DataPacket.GetChatMessage() == nil {
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return "", 0, errors.New("Did not receive a chat message")
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}
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messageID := message.DataPacket.GetChatMessage().GetMessageId()
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cr := &Protocol_Data_Chat.ChatAcknowledge{
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MessageId: proto.Uint32(messageID),
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Accepted: proto.Bool(true),
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}
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pc := &Protocol_Data_Chat.Packet{
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ChatAcknowledge: cr,
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}
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data, _ := proto.Marshal(pc)
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ack := r.constructProtocol(data, message.Channel)
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r.send(ack)
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return message.DataPacket.GetChatMessage().GetMessageText(), message.Channel, nil
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}
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// ListenAndWait is intended to be a background thread listening for all messages
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// a client will send, automaticall responding to some, and making the others available to
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// Listen()
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// Prerequisites:
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// * Must have previously issued a successful Connect()
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func (r *Ricochet) ListenAndWait() error {
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for true {
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packets, err := r.getMessages()
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if err != nil {
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return errors.New("Error attempted to get new messages")
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}
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for _, packet := range packets {
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if packet.Channel == 0 {
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// This is a Control Channel Message
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message, _ := r.decodePacket(packet, CONTROL)
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// Automatically accept new channels
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if message.ControlPacket.GetOpenChannel() != nil {
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// TODO Reject if already in use.
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cr := &Protocol_Data_Control.ChannelResult{
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ChannelIdentifier: proto.Int32(message.ControlPacket.GetOpenChannel().GetChannelIdentifier()),
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Opened: proto.Bool(true),
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}
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pc := &Protocol_Data_Control.Packet{
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ChannelResult: cr,
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}
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data, _ := proto.Marshal(pc)
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openChannel := r.constructProtocol(data, 0)
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r.logger.Print("Opening Channel: ", pc)
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r.send(openChannel)
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r.channelState[int(message.ControlPacket.GetOpenChannel().GetChannelIdentifier())] = 1
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break
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}
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if message.ControlPacket.GetChannelResult() != nil {
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channelResult := message.ControlPacket.GetChannelResult()
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if channelResult.GetOpened() == true {
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r.logger.Print("Channel Opened Successfully: ", channelResult.GetChannelIdentifier())
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r.channelState[int(message.ControlPacket.GetChannelResult().GetChannelIdentifier())] = 1
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}
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}
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} else {
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// At this point the only other expected type of message
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// is a Chat Message
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message, _ := r.decodePacket(packet, DATA)
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r.logger.Print("Receieved Data Packet: ", message)
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r.channel <- message
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}
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}
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}
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return nil
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}
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// decodePacket take a raw RicochetData message and decodes it based on a given MessageType
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func (r *Ricochet) decodePacket(packet RicochetData, t MessageType) (rm RicochetMessage, err error) {
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rm.Channel = packet.Channel
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if t == CONTROL {
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res := new(Protocol_Data_Control.Packet)
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err = proto.Unmarshal(packet.Data[:], res)
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rm.ControlPacket = res
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} else if t == AUTH {
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res := new(Protocol_Data_AuthHiddenService.Packet)
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err = proto.Unmarshal(packet.Data[:], res)
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rm.AuthPacket = res
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} else if t == DATA {
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res := new(Protocol_Data_Chat.Packet)
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err = proto.Unmarshal(packet.Data[:], res)
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rm.DataPacket = res
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}
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if err != nil {
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r.logger.Fatal("Error Unmarshalling Response", err)
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}
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return rm, err
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}
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// getMessages returns an array of new messages received from the ricochet client
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func (r *Ricochet) getMessages() ([]RicochetData, error) {
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buf, err := r.recv()
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if err != nil {
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return nil, errors.New("Failed to retrieve new messages from the client")
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}
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pos := 0
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finished := false
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datas := []RicochetData{}
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for !finished {
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size := int(binary.BigEndian.Uint16(buf[pos+0 : pos+2]))
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channel := int(binary.BigEndian.Uint16(buf[pos+2 : pos+4]))
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r.logger.Println(buf[pos+2 : pos+4])
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if pos+size > len(buf) {
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return datas, errors.New("Partial data packet received")
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}
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data := RicochetData{
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Channel: int(channel),
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Data: buf[pos+4 : pos+size],
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}
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r.logger.Println("Got new Data:", data)
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datas = append(datas, data)
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pos += size
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if pos >= len(buf) {
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finished = true
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}
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}
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return datas, nil
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}
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// recv reads data from the client, and returns the raw byte array, else error.
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func (r *Ricochet) recv() ([]byte, error) {
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buf := make([]byte, 4096)
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n, err := r.conn.Read(buf)
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r.logger.Print("Received Response From Service: ", n, err)
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if err != nil {
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return nil, err
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}
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ret := make([]byte, n)
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copy(ret[:], buf[:])
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return ret, nil
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}
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