func NewPacket(conn *net.TCPConn, raw []byte) (*Packet, error) {
if len(raw) < 8 {
return nil, errors.New("The packet is too short. The header can't be completed.")
}
if len(raw) > config.MAX_PACKET_SIZE {
return nil, errors.New("The packet exceeds the maximal packet size.")
}
contentLength := int(utils.ByteToUint(raw[0:3])) - 5
if len(raw) != contentLength+8 {
return nil, errors.New("The packet content size does not match the size value in the header: " + strconv.Itoa(len(raw)) + " != " + strconv.Itoa(int(contentLength)))
}
packet := new(Packet)
packet.Sender = conn
packet.ServiceId = utils.ByteToUint8(raw[3])
packet.PacketType = utils.ByteToUint8(raw[4])
packet.PacketId = utils.ByteToUint(raw[5:8])
packet.ContentLength = uint(contentLength)
if packet.ContentLength > 0 {
packet.Content = raw[8:]
} else {
packet.Content = []byte{}
}
packet.Raw = raw
packet.prepared = true
return packet, nil
}
func (c *UnsubscribeCommand) Handle(packet *core.Packet, service *core.Service) error {
utils.Debug("UNSUBSCRIBE packet: ", packet)
if service == nil {
return errors.New("UNSUBSCRIBE error: There is no service for this serviceId connected.")
}
if len(packet.Content) <= 0 {
return errors.New("UNSUBSCRIBE error: The packet data is too short.")
}
for i := 0; i < len(packet.Content); i++ {
c.GetMaster().SubscriptionMap.RemoveSubscription(service, utils.ByteToUint8(packet.Content[i]))
}
return nil
}
func (c *ConnectCommand) Handle(packet *core.Packet, service *core.Service) error {
utils.Debug("CONNECT packet: ", packet)
if service != nil {
return errors.New("CONNECT error: There is already a service for this serviceId connected.")
}
rawData := packet.Content
dataLength := len(rawData)
if dataLength < 2 {
return errors.New("CONNECT error: The packet data is too short.")
}
serviceName := ""
tunnelHost := ""
tunnelPorts := make(map[uint8]uint)
lenServiceName := int(utils.ByteToUint8(rawData[0]))
if dataLength < 2+lenServiceName {
return errors.New("CONNECT error: The packet data is too short. (serviceName)")
}
lenTunnelHost := int(utils.ByteToUint8(rawData[lenServiceName+1]))
if dataLength < 2+lenServiceName+lenTunnelHost {
return errors.New("CONNECT error: The packet data is too short. (tunnelHost)")
}
lenTunnelPorts := dataLength - lenServiceName - lenTunnelHost - 2
if lenTunnelPorts%3 != 0 {
return errors.New("CONNECT error: The packet data length is not valid. (tunnelPorts)")
}
if lenServiceName > 0 {
serviceName = string(rawData[1 : lenServiceName+1])
}
if lenTunnelHost > 0 {
tunnelHost = string(rawData[lenServiceName+2 : lenServiceName+2+lenTunnelHost])
}
for i := 0; i*3 < lenTunnelPorts; i++ {
pos := lenServiceName + lenTunnelHost + 2 + (i * 3)
tunnelPorts[utils.ByteToUint8(rawData[pos])] = utils.ByteToUint(rawData[pos+1 : pos+3])
}
return c.GetMaster().ConnectService(core.NewService(c.GetMaster(), packet.ServiceId, serviceName, packet.Sender, tunnelHost, tunnelPorts))
}
func (c *AskTunnelCommand) Handle(packet *core.Packet, service *core.Service) error {
utils.Debug("ASK_TUNNEL packet: ", packet)
if service == nil {
return errors.New("ASK_TUNNEL error: There is no service for this serviceId connected.")
}
if len(packet.Content) <= 0 {
return errors.New("ASK_TUNNEL error: The packet data is too small.")
}
answerPacket := core.ConstructPacket(packet.Sender, packet.ServiceId, packet.PacketType, packet.PacketId, []byte{})
services := c.GetMaster().Services
for i := 0; i < len(packet.Content); i++ {
tunnelRequest := utils.ByteToUint8(packet.Content[i])
for _, service := range services {
if port, ok := service.TunnelPorts[packet.ServiceId]; ok && service.ServiceId == tunnelRequest {
answerPacket.AppendContent(utils.UintToByte(uint(len(service.TunnelHost)+3), 2))
answerPacket.AppendContent(utils.UintToByte(uint(service.ServiceId), 1))
answerPacket.AppendContent(utils.UintToByte(port, 2))
answerPacket.AppendContent([]byte(service.TunnelHost))
}
}
}
service.Write(answerPacket)
return nil
}
func (r *PacketReader) Read(conn *net.TCPConn) (*Packet, error) {
headerBuffer := make([]byte, 8)
n, err := conn.Read(headerBuffer)
if err != nil {
return nil, err
}
if n != 8 {
return nil, errors.New("Packet header was " + strconv.Itoa(n) + " bytes.")
}
contentLength := int(utils.ByteToUint(headerBuffer[0:3])) - 5
if contentLength < 0 {
return nil, errors.New("Packet ContentLength is a negative number. ContentLength - 5 Header bytes: " + strconv.Itoa(contentLength))
}
serviceId := utils.ByteToUint8(headerBuffer[3])
packetId := utils.ByteToUint(headerBuffer[5:8])
service := r.master.ServiceById[serviceId]
// Don't trust the packet serviceId, if the connection is already connected to the master,
// instead use the connected serviceId information
setServiceId := serviceId
for sId, service := range r.master.ServiceById {
if service.Connection == conn {
setServiceId = sId
}
}
if setServiceId != serviceId {
utils.Debug("PacketReader: WARN: The serviceId of the connected service for this Connection (", conn, ") does not match the packet serviceId", serviceId, ". Overriding the packet serviceId for recover messages.")
}
recoverMessage := ConstructPacket(conn, setServiceId, PACKETTYPE_NOTHING, packetId, []byte{})
if contentLength > config.MAX_PACKET_SIZE {
r.SetRecovering(conn, recoverMessage)
return nil, errors.New("Packet header indicates too long packet: " + strconv.Itoa(contentLength))
}
if service != nil && service.Connection != conn {
r.SetRecovering(conn, recoverMessage)
return nil, errors.New("packet sender connection is not origin service connection")
}
if lastId, found := r.master.LastPacketId[serviceId]; found {
if packetId <= lastId {
r.SetRecovering(conn, recoverMessage)
return nil, errors.New("Packet header packetId is too small: " + strconv.Itoa(int(packetId)) + " <= " + strconv.Itoa(int(lastId)))
}
}
r.master.LastPacketId[serviceId] = packetId
if contentLength <= 0 {
return NewPacket(conn, headerBuffer)
}
contentBuffer := make([]byte, contentLength)
n, err = conn.Read(contentBuffer)
if err != nil {
if err != io.EOF && err.Error()[0:11] != "WSARecv tcp" {
netOpError, ok := err.(*net.OpError)
if !ok || (netOpError.Err.Error() != "use of closed network connection" && netOpError.Err.Error() != "read: connection reset by peer") {
r.SetRecovering(conn, recoverMessage)
}
}
return nil, err
}
if n != contentLength {
r.SetRecovering(conn, recoverMessage)
return nil, errors.New("Packet content does not fit into the defined content buffer size exactly: " + strconv.Itoa(n) + " != " + strconv.Itoa(contentLength))
}
return NewPacket(conn, append(headerBuffer, contentBuffer...))
}
func (r *PacketReader) Recover(conn *net.TCPConn) {
recoverBuffer := make([]byte, 4096)
recovered := false
LoopRecovering:
for !recovered {
if !r.master.IsValidConnection(conn) {
break LoopRecovering
}
n, err := conn.Read(recoverBuffer)
if err == nil && n < 8 {
// to few bytes, next try
continue
}
if err != nil {
netOpError, ok := err.(*net.OpError)
if err == io.EOF || err.Error()[0:11] == "WSARecv tcp" || (ok && netOpError.Err.Error() == "read: connection reset by peer") {
utils.Debug("PacketReader: Recovering stopped (Client disconnected) on Connection", conn)
r.master.SetValidConnection(conn, false)
break LoopRecovering
}
if ok && netOpError.Err.Error() == "use of closed network connection" {
utils.Debug("PacketReader: Recovering stopped (Lost Connection) on Connection", conn)
r.master.SetValidConnection(conn, false)
break LoopRecovering
}
_, err := conn.Write(r.recovering[conn])
if err != nil {
utils.Debug("PacketReader: Error sending recover message:", err)
netOpError, ok := err.(*net.OpError)
if err == io.EOF || err.Error()[0:11] == "WSARecv tcp" || (ok && (netOpError.Err.Error() == "use of closed network connection" || netOpError.Err.Error() == "read: connection reset by peer")) {
r.master.SetValidConnection(conn, false)
}
// Break anyway, but keep the connection valid
// if wrong
break LoopRecovering
}
utils.Debug("PacketReader: Recovering not successful, continue.")
continue
}
recoverBufferStr := []uint8{}
for _, b := range recoverBuffer {
recoverBufferStr = append(recoverBufferStr, utils.ByteToUint8(b))
}
recovered = true
for i := 1; recovered && i <= 8; i++ {
if r.recovering[conn][8-i] != recoverBuffer[n-i] {
recovered = false
}
}
}
r.recovering[conn] = []byte{}
if recovered && r.master.IsValidConnection(conn) {
utils.Debug("PacketReader: Recovering successful on Connection", conn)
} else {
utils.Debug("PacketReader: Recovering failed on Connection", conn)
}
}
