Added BackboneInterface skeleton

RNS/Interfaces/BackboneInterface.py

@@ -0,0 +1,599 @@
+# MIT License
+#
+# Copyright (c) 2016-2025 Mark Qvist / unsigned.io
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+from RNS.Interfaces.Interface import Interface
+import threading
+import socket
+import select
+import time
+import sys
+import os
+import RNS
+
+class HDLC():
+    FLAG              = 0x7E
+    ESC               = 0x7D
+    ESC_MASK          = 0x20
+
+    @staticmethod
+    def escape(data):
+        data = data.replace(bytes([HDLC.ESC]), bytes([HDLC.ESC, HDLC.ESC^HDLC.ESC_MASK]))
+        data = data.replace(bytes([HDLC.FLAG]), bytes([HDLC.ESC, HDLC.FLAG^HDLC.ESC_MASK]))
+        return data
+
+class KISS():
+    FEND              = 0xC0
+    FESC              = 0xDB
+    TFEND             = 0xDC
+    TFESC             = 0xDD
+    CMD_DATA          = 0x00
+    CMD_UNKNOWN       = 0xFE
+
+    @staticmethod
+    def escape(data):
+        data = data.replace(bytes([0xdb]), bytes([0xdb, 0xdd]))
+        data = data.replace(bytes([0xc0]), bytes([0xdb, 0xdc]))
+        return data
+
+class BackboneInterface(Interface):
+    HW_MTU            = 1048576
+    BITRATE_GUESS     = 100_000_000
+    DEFAULT_IFAC_SIZE = 16
+    AUTOCONFIGURE_MTU = True
+
+    @staticmethod
+    def get_address_for_if(name, bind_port, prefer_ipv6=False):
+        import RNS.vendor.ifaddr.niwrapper as netinfo
+        ifaddr = netinfo.ifaddresses(name)
+        if len(ifaddr) < 1:
+            raise SystemError(f"No addresses available on specified kernel interface \"{name}\" for BackboneInterface to bind to")
+
+        if (prefer_ipv6 or not netinfo.AF_INET in ifaddr) and netinfo.AF_INET6 in ifaddr:
+            bind_ip = ifaddr[netinfo.AF_INET6][0]["addr"]
+            if bind_ip.lower().startswith("fe80::"):
+                # We'll need to add the interface as scope for link-local addresses
+                return self.get_address_for_host(f"{bind_ip}%{name}", bind_port)
+            else:
+                return self.get_address_for_host(bind_ip, bind_port)
+        elif netinfo.AF_INET in ifaddr:
+            bind_ip = ifaddr[netinfo.AF_INET][0]["addr"]
+            return (bind_ip, bind_port)
+        else:
+            raise SystemError(f"No addresses available on specified kernel interface \"{name}\" for BackboneInterface to bind to")
+
+    @staticmethod
+    def get_address_for_host(name, bind_port):
+        address_info = socket.getaddrinfo(name, bind_port, proto=socket.IPPROTO_TCP)[0]
+        if address_info[0] == socket.AF_INET6:
+            return (name, bind_port, address_info[4][2], address_info[4][3])
+        elif address_info[0] == socket.AF_INET:
+            return (name, bind_port)
+        else:
+            raise SystemError(f"No suitable kernel interface available for address \"{name}\" for BackboneInterface to bind to")
+
+
+    @property
+    def clients(self):
+        return len(self.spawned_interfaces)
+
+    def __init__(self, owner, configuration):
+        super().__init__()
+
+        c            = Interface.get_config_obj(configuration)
+        name         = c["name"]
+        device       = c["device"] if "device" in c else None
+        port         = int(c["port"]) if "port" in c else None
+        bindip       = c["listen_ip"] if "listen_ip" in c else None
+        bindport     = int(c["listen_port"]) if "listen_port" in c else None
+        prefer_ipv6  = c.as_bool("prefer_ipv6") if "prefer_ipv6" in c else False
+
+        if port != None:
+            bindport = port
+
+        self.HW_MTU = BackboneInterface.HW_MTU
+
+        self.online = False
+        self.listeners = []
+        self.spawned_interfaces = []
+        
+        self.IN  = True
+        self.OUT = False
+        self.name = name
+        self.detached = False
+
+        self.mode         = RNS.Interfaces.Interface.Interface.MODE_FULL
+
+        if bindport == None:
+            raise SystemError(f"No TCP port configured for interface \"{name}\"")
+        else:
+            self.bind_port = bindport
+
+        bind_address = None
+        if device != None:
+            bind_address = self.get_address_for_if(device, self.bind_port, prefer_ipv6)
+        else:
+            if bindip == None:
+                raise SystemError(f"No TCP bind IP configured for interface \"{name}\"")
+            bind_address = self.get_address_for_host(bindip, self.bind_port)
+
+        if bind_address != None:
+            self.receives = True
+            self.bind_ip = bind_address[0]
+            self.owner = owner
+
+            # if len(bind_address) == 4:
+            #     try:
+            #         ThreadingTCP6Server.allow_reuse_address = True
+            #         self.server = ThreadingTCP6Server(bind_address, handlerFactory(self.incoming_connection))
+            #     except Exception as e:
+            #         RNS.log(f"Error while binding IPv6 socket for interface, the contained exception was: {e}", RNS.LOG_ERROR)
+            #         raise SystemError("Could not bind IPv6 socket for interface. Please check the specified \"listen_ip\" configuration option")
+            # else:
+
+            self.epoll = select.epoll()
+            self.add_listener(bind_address)
+            self.bitrate = self.BITRATE_GUESS
+            
+            self.start()
+            self.online = True
+
+        else:
+            raise SystemError("Insufficient parameters to create listener")
+
+    def start(self):
+        RNS.log(f"Starting {self}")
+        threading.Thread(target=self.__job, daemon=True).start()
+
+    def __job(self):
+        try:
+            while True:
+                events = self.epoll.poll(1)
+
+                for spawned_interface in self.spawned_interfaces:
+                    clientsocket = spawned_interface.socket
+                    for fileno, event in events:
+                        if fileno == clientsocket.fileno() and (event & select.EPOLLIN):
+                            inb = clientsocket.recv(4096)
+                            if len(inb):
+                                # print(f"READ {clientsocket}: {inb}")
+                                spawned_interface.receive(inb)
+                            else:
+                                # print(f"EOF {clientsocket}")
+                                self.epoll.unregister(fileno)
+                                clientsocket.close()
+                                spawned_interface.receive(inb)
+                        
+                        elif fileno == clientsocket.fileno() and (event & select.EPOLLOUT):
+                            # print(f"WRITE {clientsocket}")
+                            written = clientsocket.send(spawned_interface.transmit_buffer)
+                            spawned_interface.transmit_buffer = spawned_interface.transmit_buffer[written:]
+                            if len(spawned_interface.transmit_buffer) == 0: self.epoll.modify(fileno, select.EPOLLIN)
+                            self.txb += written; spawned_interface.txb += written
+                        
+                        elif fileno == clientsocket.fileno() and event & (select.EPOLLHUP):
+                           # print(f"HUP {clientsocket}")
+                           self.epoll.unregister(fileno)
+                           clientsocket.close()
+                           spawned_interface.receive(b"")
+
+                for serversocket in self.listeners:
+                    for fileno, event in events:
+                        if fileno == serversocket.fileno():
+                            connection, address = serversocket.accept()
+                            connection.setblocking(0)
+                            if self.incoming_connection(connection):
+                                self.epoll.register(connection.fileno(), select.EPOLLIN)
+                            else:
+                                connection.close()
+                        
+                        elif event & select.EPOLLHUP:
+                            self.epoll.unregister(fileno)
+                            connections[fileno].close()
+                            del connections[fileno]
+        
+        except Exception as e:
+            RNS.log(f"{self} error: {e}", RNS.LOG_ERROR)
+            RNS.trace_exception(e)
+
+        finally:
+           self.epoll.unregister(self.server_socket.fileno())
+           self.epoll.close()
+           serversocket.close()
+    
+    def add_listener(self, bind_address):
+        server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        server_socket.bind(bind_address)
+        server_socket.listen(1)
+        server_socket.setblocking(0)
+        self.epoll.register(server_socket.fileno(), select.EPOLLIN)
+        self.listeners.append(server_socket)
+        RNS.log(f"Listener added: {server_socket}")
+
+    def incoming_connection(self, socket):
+        RNS.log("Accepting incoming connection", RNS.LOG_VERBOSE)
+        spawned_configuration = {"name": "Client on "+self.name, "target_host": None, "target_port": None}
+        spawned_interface = BackboneClientInterface(self.owner, spawned_configuration, connected_socket=socket)
+        spawned_interface.OUT = self.OUT
+        spawned_interface.IN  = self.IN
+        spawned_interface.socket = socket
+        spawned_interface.target_ip = socket.getsockname()[0]
+        spawned_interface.target_port = str(socket.getsockname()[1])
+        spawned_interface.parent_interface = self
+        spawned_interface.bitrate = self.bitrate
+        spawned_interface.optimise_mtu()
+        
+        spawned_interface.ifac_size = self.ifac_size
+        spawned_interface.ifac_netname = self.ifac_netname
+        spawned_interface.ifac_netkey = self.ifac_netkey
+        if spawned_interface.ifac_netname != None or spawned_interface.ifac_netkey != None:
+            ifac_origin = b""
+            if spawned_interface.ifac_netname != None:
+                ifac_origin += RNS.Identity.full_hash(spawned_interface.ifac_netname.encode("utf-8"))
+            if spawned_interface.ifac_netkey != None:
+                ifac_origin += RNS.Identity.full_hash(spawned_interface.ifac_netkey.encode("utf-8"))
+
+            ifac_origin_hash = RNS.Identity.full_hash(ifac_origin)
+            spawned_interface.ifac_key = RNS.Cryptography.hkdf(
+                length=64,
+                derive_from=ifac_origin_hash,
+                salt=RNS.Reticulum.IFAC_SALT,
+                context=None
+            )
+            spawned_interface.ifac_identity = RNS.Identity.from_bytes(spawned_interface.ifac_key)
+            spawned_interface.ifac_signature = spawned_interface.ifac_identity.sign(RNS.Identity.full_hash(spawned_interface.ifac_key))
+
+        spawned_interface.announce_rate_target = self.announce_rate_target
+        spawned_interface.announce_rate_grace = self.announce_rate_grace
+        spawned_interface.announce_rate_penalty = self.announce_rate_penalty
+        spawned_interface.mode = self.mode
+        spawned_interface.HW_MTU = self.HW_MTU
+        spawned_interface.online = True
+        RNS.log("Spawned new BackBoneClient Interface: "+str(spawned_interface), RNS.LOG_VERBOSE)
+        RNS.Transport.interfaces.append(spawned_interface)
+        while spawned_interface in self.spawned_interfaces:
+            self.spawned_interfaces.remove(spawned_interface)
+        self.spawned_interfaces.append(spawned_interface)
+
+        return True
+
+    def received_announce(self, from_spawned=False):
+        if from_spawned: self.ia_freq_deque.append(time.time())
+
+    def sent_announce(self, from_spawned=False):
+        if from_spawned: self.oa_freq_deque.append(time.time())
+
+    def process_outgoing(self, data):
+        pass
+
+    def detach(self):
+        self.detached = True
+        self.online = False
+        if self.server != None:
+            if hasattr(self.server, "shutdown"):
+                if callable(self.server.shutdown):
+                    try:
+                        RNS.log("Detaching "+str(self), RNS.LOG_DEBUG)
+                        self.server.shutdown()
+                        self.server.server_close()
+                        self.server = None
+
+                    except Exception as e:
+                        RNS.log("Error while shutting down server for "+str(self)+": "+str(e))
+
+
+    def __str__(self):
+        if ":" in self.bind_ip:
+            ip_str = f"[{self.bind_ip}]"
+        else:
+            ip_str = f"{self.bind_ip}"
+
+        return "BackboneInterface["+self.name+"/"+ip_str+":"+str(self.bind_port)+"]"
+
+
+class BackboneClientInterface(Interface):
+    BITRATE_GUESS = 100_000_000
+    DEFAULT_IFAC_SIZE = 16
+    AUTOCONFIGURE_MTU = True
+
+    RECONNECT_WAIT = 5
+    RECONNECT_MAX_TRIES = None
+
+    # TCP socket options
+    TCP_USER_TIMEOUT = 24
+    TCP_PROBE_AFTER = 5
+    TCP_PROBE_INTERVAL = 2
+    TCP_PROBES = 12
+
+    INITIAL_CONNECT_TIMEOUT = 5
+    SYNCHRONOUS_START = True
+
+    I2P_USER_TIMEOUT = 45
+    I2P_PROBE_AFTER = 10
+    I2P_PROBE_INTERVAL = 9
+    I2P_PROBES = 5
+
+    def __init__(self, owner, configuration, connected_socket=None):
+        super().__init__()
+
+        c = Interface.get_config_obj(configuration)
+        name = c["name"]
+        target_ip = c["target_host"] if "target_host" in c and c["target_host"] != None else None
+        target_port = int(c["target_port"]) if "target_port" in c and c["target_host"] != None else None
+        kiss_framing = False
+        if "kiss_framing" in c and c.as_bool("kiss_framing") == True:
+            kiss_framing = True
+        i2p_tunneled = c.as_bool("i2p_tunneled") if "i2p_tunneled" in c else False
+        connect_timeout = c.as_int("connect_timeout") if "connect_timeout" in c else None
+        max_reconnect_tries = c.as_int("max_reconnect_tries") if "max_reconnect_tries" in c else None
+        
+        self.HW_MTU           = BackboneInterface.HW_MTU
+        self.IN               = True
+        self.OUT              = False
+        self.socket           = None
+        self.parent_interface = None
+        self.name             = name
+        self.initiator        = False
+        self.reconnecting     = False
+        self.never_connected  = True
+        self.owner            = owner
+        self.online           = False
+        self.detached         = False
+        self.kiss_framing     = kiss_framing
+        self.i2p_tunneled     = i2p_tunneled
+        self.mode             = RNS.Interfaces.Interface.Interface.MODE_FULL
+        self.bitrate          = BackboneClientInterface.BITRATE_GUESS
+        self.frame_buffer     = b""
+        self.transmit_buffer  = b""
+        
+        if max_reconnect_tries == None:
+            self.max_reconnect_tries = BackboneClientInterface.RECONNECT_MAX_TRIES
+        else:
+            self.max_reconnect_tries = max_reconnect_tries
+
+        if connected_socket != None:
+            self.receives    = True
+            self.target_ip   = None
+            self.target_port = None
+            self.socket      = connected_socket
+
+            self.set_timeouts_linux()
+            self.socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
+
+        elif target_ip != None and target_port != None:
+            self.receives    = True
+            self.target_ip   = target_ip
+            self.target_port = target_port
+            self.initiator   = True
+
+            if connect_timeout != None:
+                self.connect_timeout = connect_timeout
+            else:
+                self.connect_timeout = BackboneClientInterface.INITIAL_CONNECT_TIMEOUT
+            
+            if BackboneClientInterface.SYNCHRONOUS_START:
+                self.initial_connect()
+            else:
+                thread = threading.Thread(target=self.initial_connect)
+                thread.daemon = True
+                thread.start()
+            
+    def initial_connect(self):
+        if not self.connect(initial=True):
+            thread = threading.Thread(target=self.reconnect)
+            thread.daemon = True
+            thread.start()
+        else:
+            thread = threading.Thread(target=self.read_loop)
+            thread.daemon = True
+            thread.start()
+            if not self.kiss_framing:
+                self.wants_tunnel = True
+
+    def set_timeouts_linux(self):
+        self.socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_USER_TIMEOUT, int(BackboneClientInterface.TCP_USER_TIMEOUT * 1000))
+        self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
+        self.socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPIDLE, int(BackboneClientInterface.TCP_PROBE_AFTER))
+        self.socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPINTVL, int(BackboneClientInterface.TCP_PROBE_INTERVAL))
+        self.socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPCNT, int(BackboneClientInterface.TCP_PROBES))
+
+    def detach(self):
+        self.online = False
+        if self.socket != None:
+            if hasattr(self.socket, "close"):
+                if callable(self.socket.close):
+                    self.detached = True
+                    
+                    try:
+                        if self.socket != None:
+                            self.socket.shutdown(socket.SHUT_RDWR)
+                    except Exception as e:
+                        RNS.log("Error while shutting down socket for "+str(self)+": "+str(e))
+
+                    try:
+                        if self.socket != None:
+                            self.socket.close()
+                    except Exception as e:
+                        RNS.log("Error while closing socket for "+str(self)+": "+str(e))
+
+                    self.socket = None
+
+    def connect(self, initial=False):
+        try:
+            if initial:
+                RNS.log("Establishing TCP connection for "+str(self)+"...", RNS.LOG_DEBUG)
+
+            address_info = socket.getaddrinfo(self.target_ip, self.target_port, proto=socket.IPPROTO_TCP)[0]
+            address_family = address_info[0]
+            target_address = address_info[4]
+
+            self.socket = socket.socket(address_family, socket.SOCK_STREAM)
+            self.socket.settimeout(BackboneClientInterface.INITIAL_CONNECT_TIMEOUT)
+            self.socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
+            self.socket.connect(target_address)
+            self.socket.settimeout(None)
+            self.online  = True
+
+            if initial:
+                RNS.log("TCP connection for "+str(self)+" established", RNS.LOG_DEBUG)
+        
+        except Exception as e:
+            if initial:
+                RNS.log("Initial connection for "+str(self)+" could not be established: "+str(e), RNS.LOG_ERROR)
+                RNS.log("Leaving unconnected and retrying connection in "+str(BackboneClientInterface.RECONNECT_WAIT)+" seconds.", RNS.LOG_ERROR)
+                return False
+            
+            else:
+                raise e
+
+        self.set_timeouts_linux()
+        
+        self.online  = True
+        self.never_connected = False
+
+        return True
+
+
+    def reconnect(self):
+        if self.initiator:
+            if not self.reconnecting:
+                self.reconnecting = True
+                attempts = 0
+                while not self.online:
+                    time.sleep(BackboneClientInterface.RECONNECT_WAIT)
+                    attempts += 1
+
+                    if self.max_reconnect_tries != None and attempts > self.max_reconnect_tries:
+                        RNS.log("Max reconnection attempts reached for "+str(self), RNS.LOG_ERROR)
+                        self.teardown()
+                        break
+
+                    try:
+                        self.connect()
+
+                    except Exception as e:
+                        RNS.log("Connection attempt for "+str(self)+" failed: "+str(e), RNS.LOG_DEBUG)
+
+                if not self.never_connected:
+                    RNS.log("Reconnected socket for "+str(self)+".", RNS.LOG_INFO)
+
+                self.reconnecting = False
+                thread = threading.Thread(target=self.read_loop)
+                thread.daemon = True
+                thread.start()
+                if not self.kiss_framing:
+                    RNS.Transport.synthesize_tunnel(self)
+
+        else:
+            RNS.log("Attempt to reconnect on a non-initiator TCP interface. This should not happen.", RNS.LOG_ERROR)
+            raise IOError("Attempt to reconnect on a non-initiator TCP interface")
+
+    def process_incoming(self, data):
+        if self.online and not self.detached:
+            self.rxb += len(data)
+            if hasattr(self, "parent_interface") and self.parent_interface != None:
+                self.parent_interface.rxb += len(data)
+                        
+            self.owner.inbound(data, self)
+
+    def process_outgoing(self, data):
+        if self.online and not self.detached:
+            try:
+                self.transmit_buffer += bytes([HDLC.FLAG])+HDLC.escape(data)+bytes([HDLC.FLAG])
+                if hasattr(self, "parent_interface") and self.parent_interface != None:
+                    self.parent_interface.epoll.modify(self.socket.fileno(), select.EPOLLOUT)
+
+            except Exception as e:
+                RNS.log("Exception occurred while transmitting via "+str(self)+", tearing down interface", RNS.LOG_ERROR)
+                RNS.log("The contained exception was: "+str(e), RNS.LOG_ERROR)
+                self.teardown()
+
+    def receive(self, data_in):
+        try:
+            if len(data_in) > 0:
+                self.frame_buffer += data_in
+                flags_remaining = True
+                while flags_remaining:
+                    frame_start = self.frame_buffer.find(HDLC.FLAG)
+                    if frame_start != -1:
+                        frame_end = self.frame_buffer.find(HDLC.FLAG, frame_start+1)
+                        if frame_end != -1:
+                            frame = self.frame_buffer[frame_start+1:frame_end]
+                            frame = frame.replace(bytes([HDLC.ESC, HDLC.FLAG ^ HDLC.ESC_MASK]), bytes([HDLC.FLAG]))
+                            frame = frame.replace(bytes([HDLC.ESC, HDLC.ESC  ^ HDLC.ESC_MASK]), bytes([HDLC.ESC]))
+                            if len(frame) > RNS.Reticulum.HEADER_MINSIZE:
+                                # RNS.log(f"GOT FRAME {self}")
+                                self.process_incoming(frame)
+                            self.frame_buffer = self.frame_buffer[frame_end:]
+                        else:
+                            flags_remaining = False
+                    else:
+                        flags_remaining = False
+
+            else:
+                self.online = False
+                if self.initiator and not self.detached:
+                    RNS.log("The socket for "+str(self)+" was closed, attempting to reconnect...", RNS.LOG_WARNING)
+                    self.reconnect()
+                else:
+                    RNS.log("The socket for remote client "+str(self)+" was closed.", RNS.LOG_VERBOSE)
+                    self.teardown()
+                
+        except Exception as e:
+            self.online = False
+            RNS.log("An interface error occurred for "+str(self)+", the contained exception was: "+str(e), RNS.LOG_WARNING)
+
+            if self.initiator:
+                RNS.log("Attempting to reconnect...", RNS.LOG_WARNING)
+                self.reconnect()
+            else:
+                self.teardown()
+
+    def teardown(self):
+        if self.initiator and not self.detached:
+            RNS.log("The interface "+str(self)+" experienced an unrecoverable error and is being torn down. Restart Reticulum to attempt to open this interface again.", RNS.LOG_ERROR)
+            if RNS.Reticulum.panic_on_interface_error:
+                RNS.panic()
+
+        else:
+            RNS.log("The interface "+str(self)+" is being torn down.", RNS.LOG_VERBOSE)
+
+        self.online = False
+        self.OUT = False
+        self.IN = False
+
+        if hasattr(self, "parent_interface") and self.parent_interface != None:
+            while self in self.parent_interface.spawned_interfaces:
+                self.parent_interface.spawned_interfaces.remove(self)
+
+        if self in RNS.Transport.interfaces:
+            if not self.initiator:
+                RNS.Transport.interfaces.remove(self)
+
+
+    def __str__(self):
+        if ":" in self.target_ip:
+            ip_str = f"[{self.target_ip}]"
+        else:
+            ip_str = f"{self.target_ip}"
+
+        return "BackboneInterface["+str(self.name)+"/"+ip_str+":"+str(self.target_port)+"]"