rm protocol.txt

doc/protocol.md

@@ -0,0 +1,707 @@
+Minetest Network Protocol 36
+============================
+
+#define LATEST_PROTOCOL_VERSION 36
+
+// Server's supported network protocol range
+#define SERVER_PROTOCOL_VERSION_MIN 36
+#define SERVER_PROTOCOL_VERSION_MAX LATEST_PROTOCOL_VERSION
+
+// Client's supported network protocol range
+// The minimal version depends on whether
+// send_pre_v25_init is enabled or not
+#define CLIENT_PROTOCOL_VERSION_MIN 36
+#define CLIENT_PROTOCOL_VERSION_MAX LATEST_PROTOCOL_VERSION
+
+// Constant that differentiates the protocol from random data and other protocols
+#define PROTOCOL_ID 0x4f457403
+
+#define PASSWORD_SIZE 28       // Maximum password length. Allows for
+                               // base64-encoded SHA-1 (27+\0).
+
+#define FORMSPEC_API_VERSION 1
+#define FORMSPEC_VERSION_STRING "formspec_version[" TOSTRING(FORMSPEC_API_VERSION) "]"
+
+#define TEXTURENAME_ALLOWED_CHARS "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_.-"
+
+enum ToClientCommand
+{
+	TOCLIENT_HELLO = 0x02,
+	/*
+		Sent after TOSERVER_INIT.
+
+		u8 deployed serialisation version
+		u16 deployed network compression mode
+		u16 deployed protocol version
+		u32 supported auth methods
+		std::string username that should be used for legacy hash (for proper casing)
+	*/
+	TOCLIENT_AUTH_ACCEPT = 0x03,
+	/*
+		Message from server to accept auth.
+
+		v3s16 player's position + v3f(0,BS/2,0) floatToInt'd
+		u64 map seed
+		f1000 recommended send interval
+		u32 : supported auth methods for sudo mode
+		      (where the user can change their password)
+	*/
+	TOCLIENT_ACCEPT_SUDO_MODE = 0x04,
+	/*
+		Sent to client to show it is in sudo mode now.
+	*/
+	TOCLIENT_DENY_SUDO_MODE = 0x05,
+	/*
+		Signals client that sudo mode auth failed.
+	*/
+	TOCLIENT_ACCESS_DENIED = 0x0A,
+	/*
+		u8 reason
+		std::string custom reason (if needed, otherwise "")
+		u8 (bool) reconnect
+	*/
+
+	TOCLIENT_INIT_LEGACY = 0x10, // Obsolete
+
+	TOCLIENT_BLOCKDATA = 0x20, //TODO: Multiple blocks
+	TOCLIENT_ADDNODE = 0x21,
+	/*
+		v3s16 position
+		serialized mapnode
+		u8 keep_metadata // Added in protocol version 22
+	*/
+	TOCLIENT_REMOVENODE = 0x22,
+
+	TOCLIENT_PLAYERPOS = 0x23, // Obsolete
+	TOCLIENT_PLAYERINFO = 0x24, // Obsolete
+	TOCLIENT_OPT_BLOCK_NOT_FOUND = 0x25, // Obsolete
+	TOCLIENT_SECTORMETA = 0x26, // Obsolete
+
+	TOCLIENT_INVENTORY = 0x27,
+	/*
+		[0] u16 command
+		[2] serialized inventory
+	*/
+
+	TOCLIENT_OBJECTDATA = 0x28, // Obsolete
+
+	TOCLIENT_TIME_OF_DAY = 0x29,
+	/*
+		u16 time (0-23999)
+		Added in a later version:
+		f1000 time_speed
+	*/
+
+	TOCLIENT_CSM_FLAVOUR_LIMITS = 0x2A,
+	/*
+		u32 CSMFlavourLimits byteflag
+	 */
+
+	// (oops, there is some gap here)
+
+	TOCLIENT_CHAT_MESSAGE = 0x2F,
+	/*
+		u8 version
+		u8 message_type
+		u16 sendername length
+		wstring sendername
+		u16 length
+		wstring message
+	*/
+
+	TOCLIENT_CHAT_MESSAGE_OLD = 0x30, // Obsolete
+
+	TOCLIENT_ACTIVE_OBJECT_REMOVE_ADD = 0x31,
+	/*
+		u16 count of removed objects
+		for all removed objects {
+			u16 id
+		}
+		u16 count of added objects
+		for all added objects {
+			u16 id
+			u8 type
+			u32 initialization data length
+			string initialization data
+		}
+	*/
+
+	TOCLIENT_ACTIVE_OBJECT_MESSAGES = 0x32,
+	/*
+		for all objects
+		{
+			u16 id
+			u16 message length
+			string message
+		}
+	*/
+
+	TOCLIENT_HP = 0x33,
+	/*
+		u8 hp
+	*/
+
+	TOCLIENT_MOVE_PLAYER = 0x34,
+	/*
+		v3f1000 player position
+		f1000 player pitch
+		f1000 player yaw
+	*/
+
+	TOCLIENT_ACCESS_DENIED_LEGACY = 0x35,
+	/*
+		u16 reason_length
+		wstring reason
+	*/
+
+	TOCLIENT_PLAYERITEM = 0x36, // Obsolete
+
+	TOCLIENT_DEATHSCREEN = 0x37,
+	/*
+		u8 bool set camera point target
+		v3f1000 camera point target (to point the death cause or whatever)
+	*/
+
+	TOCLIENT_MEDIA = 0x38,
+	/*
+		u16 total number of texture bunches
+		u16 index of this bunch
+		u32 number of files in this bunch
+		for each file {
+			u16 length of name
+			string name
+			u32 length of data
+			data
+		}
+		u16 length of remote media server url (if applicable)
+		string url
+	*/
+
+	TOCLIENT_TOOLDEF = 0x39,
+	/*
+		u32 length of the next item
+		serialized ToolDefManager
+	*/
+
+	TOCLIENT_NODEDEF = 0x3a,
+	/*
+		u32 length of the next item
+		serialized NodeDefManager
+	*/
+
+	TOCLIENT_CRAFTITEMDEF = 0x3b,
+	/*
+		u32 length of the next item
+		serialized CraftiItemDefManager
+	*/
+
+	TOCLIENT_ANNOUNCE_MEDIA = 0x3c,
+
+	/*
+		u32 number of files
+		for each texture {
+			u16 length of name
+			string name
+			u16 length of sha1_digest
+			string sha1_digest
+		}
+	*/
+
+	TOCLIENT_ITEMDEF = 0x3d,
+	/*
+		u32 length of next item
+		serialized ItemDefManager
+	*/
+
+	TOCLIENT_PLAY_SOUND = 0x3f,
+	/*
+		s32 sound_id
+		u16 len
+		u8[len] sound name
+		s32 gain*1000
+		u8 type (0=local, 1=positional, 2=object)
+		s32[3] pos_nodes*10000
+		u16 object_id
+		u8 loop (bool)
+	*/
+
+	TOCLIENT_STOP_SOUND = 0x40,
+	/*
+		s32 sound_id
+	*/
+
+	TOCLIENT_PRIVILEGES = 0x41,
+	/*
+		u16 number of privileges
+		for each privilege
+			u16 len
+			u8[len] privilege
+	*/
+
+	TOCLIENT_INVENTORY_FORMSPEC = 0x42,
+	/*
+		u32 len
+		u8[len] formspec
+	*/
+
+	TOCLIENT_DETACHED_INVENTORY = 0x43,
+	/*
+		[0] u16 command
+		u16 len
+		u8[len] name
+		[2] serialized inventory
+	*/
+
+	TOCLIENT_SHOW_FORMSPEC = 0x44,
+	/*
+		[0] u16 command
+		u32 len
+		u8[len] formspec
+		u16 len
+		u8[len] formname
+	*/
+
+	TOCLIENT_MOVEMENT = 0x45,
+	/*
+		f1000 movement_acceleration_default
+		f1000 movement_acceleration_air
+		f1000 movement_acceleration_fast
+		f1000 movement_speed_walk
+		f1000 movement_speed_crouch
+		f1000 movement_speed_fast
+		f1000 movement_speed_climb
+		f1000 movement_speed_jump
+		f1000 movement_liquid_fluidity
+		f1000 movement_liquid_fluidity_smooth
+		f1000 movement_liquid_sink
+		f1000 movement_gravity
+	*/
+
+	TOCLIENT_SPAWN_PARTICLE = 0x46,
+	/*
+		v3f1000 pos
+		v3f1000 velocity
+		v3f1000 acceleration
+		f1000 expirationtime
+		f1000 size
+		u8 bool collisiondetection
+		u8 bool vertical
+		u32 len
+		u8[len] texture
+		u8 collision_removal
+	*/
+
+	TOCLIENT_ADD_PARTICLESPAWNER = 0x47,
+	/*
+		u16 amount
+		f1000 spawntime
+		v3f1000 minpos
+		v3f1000 maxpos
+		v3f1000 minvel
+		v3f1000 maxvel
+		v3f1000 minacc
+		v3f1000 maxacc
+		f1000 minexptime
+		f1000 maxexptime
+		f1000 minsize
+		f1000 maxsize
+		u8 bool collisiondetection
+		u8 bool vertical
+		u32 len
+		u8[len] texture
+		u32 id
+		u8 collision_removal
+	*/
+
+	TOCLIENT_DELETE_PARTICLESPAWNER_LEGACY = 0x48, // Obsolete
+
+	TOCLIENT_HUDADD = 0x49,
+	/*
+		u32 id
+		u8 type
+		v2f1000 pos
+		u32 len
+		u8[len] name
+		v2f1000 scale
+		u32 len2
+		u8[len2] text
+		u32 number
+		u32 item
+		u32 dir
+		v2f1000 align
+		v2f1000 offset
+		v3f1000 world_pos
+		v2s32 size
+	*/
+
+	TOCLIENT_HUDRM = 0x4a,
+	/*
+		u32 id
+	*/
+
+	TOCLIENT_HUDCHANGE = 0x4b,
+	/*
+		u32 id
+		u8 stat
+		[v2f1000 data |
+		 u32 len
+		 u8[len] data |
+		 u32 data]
+	*/
+
+	TOCLIENT_HUD_SET_FLAGS = 0x4c,
+	/*
+		u32 flags
+		u32 mask
+	*/
+
+	TOCLIENT_HUD_SET_PARAM = 0x4d,
+	/*
+		u16 param
+		u16 len
+		u8[len] value
+	*/
+
+	TOCLIENT_BREATH = 0x4e,
+	/*
+		u16 breath
+	*/
+
+	TOCLIENT_SET_SKY = 0x4f,
+	/*
+		u8[4] color (ARGB)
+		u8 len
+		u8[len] type
+		u16 count
+		foreach count:
+			u8 len
+			u8[len] param
+		u8 clouds (boolean)
+	*/
+
+	TOCLIENT_OVERRIDE_DAY_NIGHT_RATIO = 0x50,
+	/*
+		u8 do_override (boolean)
+		u16 day-night ratio 0...65535
+	*/
+
+	TOCLIENT_LOCAL_PLAYER_ANIMATIONS = 0x51,
+	/*
+		v2s32 stand/idle
+		v2s32 walk
+		v2s32 dig
+		v2s32 walk+dig
+		f1000 frame_speed
+	*/
+
+	TOCLIENT_EYE_OFFSET = 0x52,
+	/*
+		v3f1000 first
+		v3f1000 third
+	*/
+
+	TOCLIENT_DELETE_PARTICLESPAWNER = 0x53,
+	/*
+		u32 id
+	*/
+
+	TOCLIENT_CLOUD_PARAMS = 0x54,
+	/*
+		f1000 density
+		u8[4] color_diffuse (ARGB)
+		u8[4] color_ambient (ARGB)
+		f1000 height
+		f1000 thickness
+		v2f1000 speed
+	*/
+
+	TOCLIENT_FADE_SOUND = 0x55,
+	/*
+		s32 sound_id
+		float step
+		float gain
+	*/
+	TOCLIENT_UPDATE_PLAYER_LIST = 0x56,
+	/*
+	 	u8 type
+	 	u16 number of players
+		for each player
+			u16 len
+			u8[len] player name
+	*/
+
+	TOCLIENT_SRP_BYTES_S_B = 0x60,
+	/*
+		Belonging to AUTH_MECHANISM_SRP.
+
+		std::string bytes_s
+		std::string bytes_B
+	*/
+
+	TOCLIENT_NUM_MSG_TYPES = 0x61,
+};
+
+enum ToServerCommand
+{
+	TOSERVER_INIT = 0x02,
+	/*
+		Sent first after connected.
+
+		u8 serialisation version (=SER_FMT_VER_HIGHEST_READ)
+		u16 supported network compression modes
+		u16 minimum supported network protocol version
+		u16 maximum supported network protocol version
+		std::string player name
+	*/
+
+	TOSERVER_INIT_LEGACY = 0x10, // Obsolete
+
+	TOSERVER_INIT2 = 0x11,
+	/*
+		Sent as an ACK for TOCLIENT_INIT.
+		After this, the server can send data.
+
+		[0] u16 TOSERVER_INIT2
+	*/
+
+	TOSERVER_GETBLOCK = 0x20, // Obsolete
+	TOSERVER_ADDNODE = 0x21, // Obsolete
+	TOSERVER_REMOVENODE = 0x22, // Obsolete
+
+	TOSERVER_PLAYERPOS = 0x23,
+	/*
+		[0] u16 command
+		[2] v3s32 position*100
+		[2+12] v3s32 speed*100
+		[2+12+12] s32 pitch*100
+		[2+12+12+4] s32 yaw*100
+		[2+12+12+4+4] u32 keyPressed
+		[2+12+12+4+4+1] u8 fov*80
+		[2+12+12+4+4+4+1] u8 ceil(wanted_range / MAP_BLOCKSIZE)
+	*/
+
+	TOSERVER_GOTBLOCKS = 0x24,
+	/*
+		[0] u16 command
+		[2] u8 count
+		[3] v3s16 pos_0
+		[3+6] v3s16 pos_1
+		...
+	*/
+
+	TOSERVER_DELETEDBLOCKS = 0x25,
+	/*
+		[0] u16 command
+		[2] u8 count
+		[3] v3s16 pos_0
+		[3+6] v3s16 pos_1
+		...
+	*/
+
+	TOSERVER_ADDNODE_FROM_INVENTORY = 0x26, // Obsolete
+	TOSERVER_CLICK_OBJECT = 0x27, // Obsolete
+	TOSERVER_GROUND_ACTION = 0x28, // Obsolete
+	TOSERVER_RELEASE = 0x29, // Obsolete
+	TOSERVER_SIGNTEXT = 0x30, // Obsolete
+
+	TOSERVER_INVENTORY_ACTION = 0x31,
+	/*
+		See InventoryAction in inventorymanager.h
+	*/
+
+	TOSERVER_CHAT_MESSAGE = 0x32,
+	/*
+		u16 length
+		wstring message
+	*/
+
+	TOSERVER_SIGNNODETEXT = 0x33, // Obsolete
+	TOSERVER_CLICK_ACTIVEOBJECT = 0x34, // Obsolete
+
+	TOSERVER_DAMAGE = 0x35,
+	/*
+		u8 amount
+	*/
+
+	TOSERVER_PASSWORD_LEGACY = 0x36, // Obsolete
+
+	TOSERVER_PLAYERITEM = 0x37,
+	/*
+		Sent to change selected item.
+
+		[0] u16 TOSERVER_PLAYERITEM
+		[2] u16 item
+	*/
+
+	TOSERVER_RESPAWN = 0x38,
+	/*
+		u16 TOSERVER_RESPAWN
+	*/
+
+	TOSERVER_INTERACT = 0x39,
+	/*
+		[0] u16 command
+		[2] u8 action
+		[3] u16 item
+		[5] u32 length of the next item
+		[9] serialized PointedThing
+		actions:
+		0: start digging (from undersurface) or use
+		1: stop digging (all parameters ignored)
+		2: digging completed
+		3: place block or item (to abovesurface)
+		4: use item
+	*/
+
+	TOSERVER_REMOVED_SOUNDS = 0x3a,
+	/*
+		u16 len
+		s32[len] sound_id
+	*/
+
+	TOSERVER_NODEMETA_FIELDS = 0x3b,
+	/*
+		v3s16 p
+		u16 len
+		u8[len] form name (reserved for future use)
+		u16 number of fields
+		for each field:
+			u16 len
+			u8[len] field name
+			u32 len
+			u8[len] field value
+	*/
+
+	TOSERVER_INVENTORY_FIELDS = 0x3c,
+	/*
+		u16 len
+		u8[len] form name (reserved for future use)
+		u16 number of fields
+		for each field:
+			u16 len
+			u8[len] field name
+			u32 len
+			u8[len] field value
+	*/
+
+	TOSERVER_REQUEST_MEDIA = 0x40,
+	/*
+		u16 number of files requested
+		for each file {
+			u16 length of name
+			string name
+		}
+	*/
+
+	TOSERVER_RECEIVED_MEDIA = 0x41, // Obsolete
+	TOSERVER_BREATH = 0x42, // Obsolete
+
+	TOSERVER_CLIENT_READY = 0x43,
+	/*
+		u8 major
+		u8 minor
+		u8 patch
+		u8 reserved
+		u16 len
+		u8[len] full_version_string
+	*/
+
+	TOSERVER_FIRST_SRP = 0x50,
+	/*
+		Belonging to AUTH_MECHANISM_FIRST_SRP.
+
+		std::string srp salt
+		std::string srp verification key
+		u8 is_empty (=1 if password is empty, 0 otherwise)
+	*/
+
+	TOSERVER_SRP_BYTES_A = 0x51,
+	/*
+		Belonging to AUTH_MECHANISM_SRP,
+			depending on current_login_based_on.
+
+		std::string bytes_A
+		u8 current_login_based_on : on which version of the password's
+		                            hash this login is based on (0 legacy hash,
+		                            or 1 directly the password)
+	*/
+
+	TOSERVER_SRP_BYTES_M = 0x52,
+	/*
+		Belonging to AUTH_MECHANISM_SRP.
+
+		std::string bytes_M
+	*/
+
+	TOSERVER_NUM_MSG_TYPES = 0x53,
+};
+
+enum AuthMechanism
+{
+	// reserved
+	AUTH_MECHANISM_NONE = 0,
+
+	// SRP based on the legacy hash
+	AUTH_MECHANISM_LEGACY_PASSWORD = 1 << 0,
+
+	// SRP based on the srp verification key
+	AUTH_MECHANISM_SRP = 1 << 1,
+
+	// Establishes a srp verification key, for first login and password changing
+	AUTH_MECHANISM_FIRST_SRP = 1 << 2,
+};
+
+enum AccessDeniedCode {
+	SERVER_ACCESSDENIED_WRONG_PASSWORD,
+	SERVER_ACCESSDENIED_UNEXPECTED_DATA,
+	SERVER_ACCESSDENIED_SINGLEPLAYER,
+	SERVER_ACCESSDENIED_WRONG_VERSION,
+	SERVER_ACCESSDENIED_WRONG_CHARS_IN_NAME,
+	SERVER_ACCESSDENIED_WRONG_NAME,
+	SERVER_ACCESSDENIED_TOO_MANY_USERS,
+	SERVER_ACCESSDENIED_EMPTY_PASSWORD,
+	SERVER_ACCESSDENIED_ALREADY_CONNECTED,
+	SERVER_ACCESSDENIED_SERVER_FAIL,
+	SERVER_ACCESSDENIED_CUSTOM_STRING,
+	SERVER_ACCESSDENIED_SHUTDOWN,
+	SERVER_ACCESSDENIED_CRASH,
+	SERVER_ACCESSDENIED_MAX,
+};
+
+enum NetProtoCompressionMode {
+	NETPROTO_COMPRESSION_NONE = 0,
+};
+
+const static std::string accessDeniedStrings[SERVER_ACCESSDENIED_MAX] = {
+	"Invalid password",
+	"Your client sent something the server didn't expect.  Try reconnecting or updating your client",
+	"The server is running in simple singleplayer mode.  You cannot connect.",
+	"Your client's version is not supported.\nPlease contact server administrator.",
+	"Player name contains disallowed characters.",
+	"Player name not allowed.",
+	"Too many users.",
+	"Empty passwords are disallowed.  Set a password and try again.",
+	"Another client is connected with this name.  If your client closed unexpectedly, try again in a minute.",
+	"Server authentication failed.  This is likely a server error.",
+	"",
+	"Server shutting down.",
+	"This server has experienced an internal error. You will now be disconnected."
+};
+
+enum PlayerListModifer: u8
+{
+	PLAYER_LIST_INIT,
+	PLAYER_LIST_ADD,
+	PLAYER_LIST_REMOVE,
+};
+
+enum CSMFlavourLimit : u64 {
+	CSM_FL_NONE = 0x00000000,
+	CSM_FL_LOOKUP_NODES = 0x00000001, // Limit node lookups
+	CSM_FL_CHAT_MESSAGES = 0x00000002, // Disable chat message sending from CSM
+	CSM_FL_READ_ITEMDEFS = 0x00000004, // Disable itemdef lookups
+	CSM_FL_READ_NODEDEFS = 0x00000008, // Disable nodedef lookups
+	CSM_FL_ALL = 0xFFFFFFFF,
+};
+
+

doc/protocol.txt

@@ -1,108 +0,0 @@
-Minetest protocol (incomplete, early draft):
-Updated 2011-06-18
-
-A custom protocol over UDP.
-Integers are big endian.
-Refer to connection.{h,cpp} for further reference.
-
-Initialization:
-- A dummy reliable packet with peer_id=PEER_ID_INEXISTENT=0 is sent to the server:
-	- Actually this can be sent without the reliable packet header, too, i guess,
-	  but the sequence number in the header allows the sender to re-send the
-	  packet without accidentally getting a double initialization.
-	- Packet content:
-		# Basic header
-		u32 protocol_id = PROTOCOL_ID = 0x4f457403
-		u16 sender_peer_id = PEER_ID_INEXISTENT = 0
-		u8 channel = 0
-		# Reliable packet header
-		u8 type = TYPE_RELIABLE = 3
-		u16 seqnum = SEQNUM_INITIAL = 65500
-		# Original packet header
-		u8 type = TYPE_ORIGINAL = 1
-		# And no actual payload.
-- Server responds with something like this:
-	- Packet content:
-		# Basic header
-		u32 protocol_id = PROTOCOL_ID = 0x4f457403
-		u16 sender_peer_id = PEER_ID_INEXISTENT = 0
-		u8 channel = 0
-		# Reliable packet header
-		u8 type = TYPE_RELIABLE = 3
-		u16 seqnum = SEQNUM_INITIAL = 65500
-		# Control packet header
-		u8 type = TYPE_CONTROL = 0
-		u8 controltype = CONTROLTYPE_SET_PEER_ID = 1
-		u16 peer_id_new = assigned peer id to client (other than 0 or 1)
-- Then the connection can be disconnected by sending:
-	- Packet content:
-		# Basic header
-		u32 protocol_id = PROTOCOL_ID = 0x4f457403
-		u16 sender_peer_id = whatever was gotten in CONTROLTYPE_SET_PEER_ID
-		u8 channel = 0
-		# Control packet header
-		u8 type = TYPE_CONTROL = 0
-		u8 controltype = CONTROLTYPE_DISCO = 3
-
-- Here's a quick untested connect-disconnect done in PHP:
-# host: ip of server (use gethostbyname(hostname) to get from a dns name)
-# port: port of server
-function check_if_minetestserver_up($host, $port)
-{
-	$socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
-	$timeout = array("sec" => 1, "usec" => 0);
-	socket_set_option($socket, SOL_SOCKET, SO_RCVTIMEO, $timeout);
-	$buf = "\x4f\x45\x74\x03\x00\x00\x00\x03\xff\xdc\x01";
-	socket_sendto($socket, $buf, strlen($buf), 0, $host, $port);
-	$buf = socket_read($socket, 1000);
-	if($buf != "")
-	{
-		# We got a reply! read the peer id from it.
-		$peer_id = substr($buf, 9, 2);
-		
-		# Disconnect
-		$buf = "\x4f\x45\x74\x03".$peer_id."\x00\x00\x03";
-		socket_sendto($socket, $buf, strlen($buf), 0, $host, $port);
-		socket_close($socket);
-		
-		return true;
-	}
-	return false;
-}
-
-- Here's a Python script for checking if a minetest server is up, confirmed working
-#!/usr/bin/env python
-import sys, time, socket
-address = ""
-port = 30000
-if len(sys.argv) <= 1:
-    print("Usage: %s <address>" % sys.argv[0])
-    exit()
-if ':' in sys.argv[1]:
-    address = sys.argv[1].split(':')[0]
-    try:
-        port = int(sys.argv[1].split(':')[1])
-    except ValueError:
-        print("Please specify a valid port")
-        exit()
-else:
-    address = sys.argv[1]
-
-try:
-    start = time.time()
-    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
-    sock.settimeout(2.0)
-    buf = "\x4f\x45\x74\x03\x00\x00\x00\x01"
-    sock.sendto(buf, (address, port))
-    data, addr = sock.recvfrom(1000)
-    if data:
-        peer_id = data[12:14]
-        buf = "\x4f\x45\x74\x03" + peer_id + "\x00\x00\x03"
-        sock.sendto(buf, (address, port))
-        sock.close()
-        end = time.time()
-        print("%s is up (%0.5fms)" % (sys.argv[1],end-start))
-    else:
-        print("%s seems to be down " % sys.argv[1])
-except:
-    print("%s seems to be down " % sys.argv[1])