UDP Class
Properties Methods Events Config Settings Errors
The User Datagram Protocol (UDP) class is used to facilitate UDP (datagram) communications. It can act both as a client and a server and communicate with any number of hosts simultaneously, as well as generate and receive broadcast packets.
Syntax
ipworks.UDP
Remarks
The interface of the class is similar to the interface of TCPClient, only much simpler. The class is activated or deactivated through the Active property. This property enables or disables sends or receives. The data can be sent in the same way as TCPClient, using the Send method and specifying the text to send. The destination is specified using the RemoteHost and RemotePort properties. Inbound data are received through the DataIn event.
If the UseConnection configuration setting is set to True, then a local association is created with the remote host. Otherwise, the class can receive datagrams (packets) from any host, and send datagrams to any host. Packets can be broadcast on the local net by setting the destination (RemoteHost) to 255.255.255.255.
The operation of the class is almost completely asynchronous. All calls, except the ones that deal with domain name resolution, operate through Windows messages (no blocking calls). The gain in performance is considerable when compared to using blocking calls.
Property List
The following is the full list of the properties of the class with short descriptions. Click on the links for further details.
AcceptData | This property indicates whether data reception is currently enabled. |
Active | This property indicates whether the class is active. |
DontRoute | If this property is set to True, it forces the socket to send data directly to the interface (no routing). |
LocalHost | This property includes the name of the local host or user-assigned IP interface through which connections are initiated or accepted. |
LocalPort | This property includes the User Datagram Protocol (UDP) port in the local host where UDP binds. |
RemoteHost | This property includes the address of the remote host. Domain names are resolved to IP addresses. |
RemotePort | This property specifies the User Datagram Protocol (UDP) port in the remote host. |
TimeToLive | This property specifies the maximum number of subnets that a datagram can traverse. |
Method List
The following is the full list of the methods of the class with short descriptions. Click on the links for further details.
Activate | This method enables sending and receiving of data. |
Config | Sets or retrieves a configuration setting. |
Deactivate | This method disables sending and receive of data. |
DoEvents | This method processes events from the internal message queue. |
PauseData | This method pauses data reception. |
ProcessData | This method reenables data reception after a call to PauseData . |
Reset | This method will reset the class. |
ResolveRemoteHost | This method resolves the hostname in RemoteHost to an IP address. |
Send | This method sends binary data to the remote host. |
SendBytes | This method sends binary data to the remote host. |
SendText | This method sends text to the remote host. |
Event List
The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.
DataIn | This event is fired when data are received. |
Error | Fired when information is available about errors during data delivery. |
ReadyToSend | This event is fired when the class is ready to send data. |
Config Settings
The following is a list of config settings for the class with short descriptions. Click on the links for further details.
CaptureIPPacketInfo | Used to capture the packet information. |
DelayHostResolution | Whether the hostname is resolved when RemoteHost is set. |
DestinationAddress | Used to get the destination address from the packet information. |
DontFragment | Used to set the Don't Fragment flag of outgoing packets. |
LocalHost | The name of the local host through which connections are initiated or accepted. |
LocalPort | The port in the local host where the class binds. |
MaxPacketSize | The maximum length of the packets that can be received. |
QOSDSCPValue | Used to specify an arbitrary QOS/DSCP setting (optional). |
QOSTrafficType | Used to specify QOS/DSCP settings (optional). |
ShareLocalPort | If set to True, allows more than one instance of the class to be active on the same local port. |
UseConnection | Determines whether to use a connected socket. |
UseIPv6 | Whether or not to use IPv6. |
AbsoluteTimeout | Determines whether timeouts are inactivity timeouts or absolute timeouts. |
FirewallData | Used to send extra data to the firewall. |
InBufferSize | The size in bytes of the incoming queue of the socket. |
OutBufferSize | The size in bytes of the outgoing queue of the socket. |
BuildInfo | Information about the product's build. |
GUIAvailable | Whether or not a message loop is available for processing events. |
LicenseInfo | Information about the current license. |
MaskSensitiveData | Whether sensitive data is masked in log messages. |
UseDaemonThreads | Whether threads created by the class are daemon threads. |
UseInternalSecurityAPI | Whether or not to use the system security libraries or an internal implementation. |
AcceptData Property (UDP Class)
This property indicates whether data reception is currently enabled.
Syntax
public boolean isAcceptData();
Default Value
True
Remarks
This property indicates whether data reception is currently enabled. When false, data reception is disabled and the DataIn event will not fire. Use the PauseData and ProcessData methods to pause and resume data reception.
This property is read-only and not available at design time.
Active Property (UDP Class)
This property indicates whether the class is active.
Syntax
public boolean isActive();
Default Value
False
Remarks
This property indicates whether the class is currently active and can send or receive data. Use the Activate and Deactivate methods to control whether the class is active.
This property is read-only and not available at design time.
DontRoute Property (UDP Class)
If this property is set to True, it forces the socket to send data directly to the interface (no routing).
Syntax
public boolean isDontRoute(); public void setDontRoute(boolean dontRoute);
Default Value
False
Remarks
If this property is set to True, it forces the socket to send data directly to the interface (no routing). Normally, IP sockets send packets of data through routers and gateways until they reach the final destination. If this property is set to True, then data will be delivered on the local subnet only.
This property is not available at design time.
LocalHost Property (UDP Class)
This property includes the name of the local host or user-assigned IP interface through which connections are initiated or accepted.
Syntax
public String getLocalHost(); public void setLocalHost(String localHost);
Default Value
""
Remarks
The LocalHost property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.
In multihomed hosts (machines with more than one IP interface) setting LocalHost to the IP address of an interface will make the class initiate connections (or accept in the case of server classs) only through that interface. It is recommended to provide an IP address rather than a hostname when setting this property to ensure the desired interface is used.
If the class is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multihomed hosts (machines with more than one IP interface).
Note: LocalHost is not persistent. You must always set it in code, and never in the property window.
LocalPort Property (UDP Class)
This property includes the User Datagram Protocol (UDP) port in the local host where UDP binds.
Syntax
public int getLocalPort(); public void setLocalPort(int localPort);
Default Value
0
Remarks
The LocalPort property must be set before UDP is activated (Active is set to True). This instructs the class to bind to a specific port (or communication endpoint) in the local machine.
Setting it to 0 (default) enables the Transmission Control Protocol (TCP)/IP stack to choose a port at random. The chosen port will be shown by the LocalPort property after the connection is established.
LocalPort cannot be changed once the class is Active. Any attempt to set the LocalPort property when the class is Active will generate an error.
The LocalPort property is useful when trying to connect to services that require a trusted port on the client side.
RemoteHost Property (UDP Class)
This property includes the address of the remote host. Domain names are resolved to IP addresses.
Syntax
public String getRemoteHost(); public void setRemoteHost(String remoteHost);
Default Value
""
Remarks
The RemoteHost property specifies the IP address (IP number in dotted internet format) or domain name of the remote host.
If RemoteHost is set to 255.255.255.255, the class broadcasts data on the local subnet.
If the RemoteHost property is set to a domain name, a DNS request is initiated, and upon successful termination of the request, the RemoteHost property is set to the corresponding address. If the search is not successful, an error is returned.
If UseConnection is set to True, the RemoteHost must be set before the class is activated (Active is set to True).
RemotePort Property (UDP Class)
This property specifies the User Datagram Protocol (UDP) port in the remote host.
Syntax
public int getRemotePort(); public void setRemotePort(int remotePort);
Default Value
0
Remarks
The RemotePort is the UDP port on the RemoteHost to send UDP datagrams to.
A valid port number (a value between 1 and 65535) is required.
If UseConnection is set to True, the RemotePort must be set before the class is activated (Active is set to True).
TimeToLive Property (UDP Class)
This property specifies the maximum number of subnets that a datagram can traverse.
Syntax
public int getTimeToLive(); public void setTimeToLive(int timeToLive);
Default Value
0
Remarks
The default value for this property is 0, which tells the class to use the default time-to-live (TTL) value of the underlying Transmission Control Protocol (TCP)/IP subsystem. Depending on the application, you can specify a value between 1 and 255.
Activate Method (UDP Class)
This method enables sending and receiving of data.
Syntax
public void activate();
Remarks
This method enables sending and receiving of data. When called, the class will create a communication endpoint (socket) that can be used for sending and receiving User Datagram Protocol (UDP) messages. This method must be called before using the class to send and receive data.
If the UseConnection configuration setting is set to true, then a local association (connection) to the remote host is also created.
Config Method (UDP Class)
Sets or retrieves a configuration setting.
Syntax
public String config(String configurationString);
Remarks
Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.
These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.
To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).
To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.
Deactivate Method (UDP Class)
This method disables sending and receive of data.
Syntax
public void deactivate();
Remarks
This method disables sending and receiving of data. When called, the class will destroy the existing socket and disable data communications.
DoEvents Method (UDP Class)
This method processes events from the internal message queue.
Syntax
public void doEvents();
Remarks
When DoEvents is called, the class processes any available events. If no events are available, it waits for a preset period of time, and then returns.
PauseData Method (UDP Class)
This method pauses data reception.
Syntax
public void pauseData();
Remarks
This method pauses data reception when called. While data reception is paused, the DataIn event will not fire. Call ProcessData to reenable data reception.
ProcessData Method (UDP Class)
This method reenables data reception after a call to PauseData .
Syntax
public void processData();
Remarks
This method reenables data reception after a previous call to PauseData. When PauseData is called, the DataIn event will not fire. To reenable data reception and allow DataIn to fire, call this method.
Note: This method is used only after previously calling PauseData. It does not need to be called to process incoming data by default.
Reset Method (UDP Class)
This method will reset the class.
Syntax
public void reset();
Remarks
This method will reset the class's properties to their default values.
ResolveRemoteHost Method (UDP Class)
This method resolves the hostname in RemoteHost to an IP address.
Syntax
public void resolveRemoteHost();
Remarks
This method resolves the hostname specified by RemoteHost to an IP address. The resolved value is available in the RemoteHost property after this method returns.
In most cases, calling this method is not necessary; the class will resolve the hostname automatically when needed. If DelayHostResolution is true, this method may be called to manually resolve RemoteHost, if desired.
Send Method (UDP Class)
This method sends binary data to the remote host.
Syntax
public void send(byte[] text);
Remarks
This method sends the specified binary data to the remote host. To send text, use the SendText method instead.
Example. Send Data:
UDPControl.LocalPort = 8765
UDPControl.RemotePort = 8765
UDPControl.RemoteHost = "HostNameOrIPAddress"
UDPControl.Active = True
UDPControl.SendText("Hello!")
SendBytes Method (UDP Class)
This method sends binary data to the remote host.
Syntax
public void sendBytes(byte[] data);
Remarks
This method sends the specified binary data to the remote host. To send text, use the SendText method instead.
Example. Send Data:
UDPControl.LocalPort = 8765
UDPControl.RemotePort = 8765
UDPControl.RemoteHost = "HostNameOrIPAddress"
UDPControl.Active = True
UDPControl.SendText("Hello!")
SendText Method (UDP Class)
This method sends text to the remote host.
Syntax
public void sendText(String text);
Remarks
This method sends the specified text to the remote host. To send binary data, use the SendBytes method instead.
Example. Send Data:
UDPControl.LocalPort = 8765
UDPControl.RemotePort = 8765
UDPControl.RemoteHost = "HostNameOrIPAddress"
UDPControl.Active = True
UDPControl.SendText("Hello!")
DataIn Event (UDP Class)
This event is fired when data are received.
Syntax
public class DefaultUDPEventListener implements UDPEventListener { ... public void dataIn(UDPDataInEvent e) {} ... } public class UDPDataInEvent { public byte[] datagram; public String sourceAddress; public int sourcePort; }
Remarks
The DataIn event is fired every time a new datagram is received.
Datagram contains the packet as sent by the remote host.
SourceAddress contains the IP number (Internet address) of the remote host, and SourcePort contains the port from which the packet originated.
Note: Events are not re-entrant. Performing time-consuming operations within this event will prevent it from firing again in a timely manner and may affect overall performance.
Error Event (UDP Class)
Fired when information is available about errors during data delivery.
Syntax
public class DefaultUDPEventListener implements UDPEventListener { ... public void error(UDPErrorEvent e) {} ... } public class UDPErrorEvent { public int errorCode; public String description; }
Remarks
The Error event is fired in case of exceptional conditions during message processing. Normally the class throws an exception.
The ErrorCode parameter contains an error code, and the Description parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.
ReadyToSend Event (UDP Class)
This event is fired when the class is ready to send data.
Syntax
public class DefaultUDPEventListener implements UDPEventListener { ... public void readyToSend(UDPReadyToSendEvent e) {} ... } public class UDPReadyToSendEvent { }
Remarks
The ReadyToSend event indicates that the underlying Transmission Control Protocol (TCP)/IP subsystem is ready to accept data after a failed Send.
Config Settings (UDP Class)
The class accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.UDP Config Settings
The default value for this setting is False.
Note: This setting is available only in Windows.
The default value is false.
Note: This setting is available only in Windows.
In multihomed hosts (machines with more than one IP interface), setting LocalHost to the value of an interface will make the class initiate connections (or accept in the case of server classs) only through that interface.
If the class is connected, the LocalHost setting shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multihomed hosts (machines with more than one IP interface).
Setting this to 0 (default) enables the system to choose a port at random. The chosen port will be shown by LocalPort after the connection is established.
LocalPort cannot be changed once a connection is made. Any attempt to set this when a connection is active will generate an error.
This configuration setting is useful when trying to connect to services that require a trusted port on the client side. An example is the remote shell (rsh) service in UNIX systems.
Note: This setting uses the qWAVE API and is available only on Windows 7, Windows Server 2008 R2, and later.
Note: This setting uses the qWAVE API and is available only on Windows Vista and Windows Server 2008 or above.
Note: QOSTrafficType must be set before setting Active to True.
The default value for this setting is False.
The default value for this setting is False.
Socket Config Settings
Note: This option is not valid for User Datagram Protocol (UDP) ports.
Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the class is activated the InBufferSize reverts to its defined size. The same happens if you attempt to make it too large or too small.
Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the class is activated the OutBufferSize reverts to its defined size. The same happens if you attempt to make it too large or too small.
Base Config Settings
In some non-GUI applications, an invalid message loop may be discovered that will result in errant behavior. In these cases, setting GUIAvailable to false will ensure that the class does not attempt to process external events.
- Product: The product the license is for.
- Product Key: The key the license was generated from.
- License Source: Where the license was found (e.g., RuntimeLicense, License File).
- License Type: The type of license installed (e.g., Royalty Free, Single Server).
- Last Valid Build: The last valid build number for which the license will work.
This setting only works on these classes: AS3Receiver, AS3Sender, Atom, Client(3DS), FTP, FTPServer, IMAP, OFTPClient, SSHClient, SCP, Server(3DS), Sexec, SFTP, SFTPServer, SSHServer, TCPClient, TCPServer.
Setting this configuration setting to true tells the class to use the internal implementation instead of using the system security libraries.
This setting is set to false by default on all platforms.
Trappable Errors (UDP Class)
UDP Errors
104 | UDP is already Active. |
106 | You cannot change the LocalPort while the class is Active. |
107 | You cannot change the LocalHost at this time. A connection is in progress. |
109 | The class must be Active for this operation. |
112 | You cannot change MaxPacketSize while the class is Active. |
113 | You cannot change ShareLocalPort option while the class is Active. |
114 | You cannot change RemoteHost when UseConnection is set and the class Active. |
115 | You cannot change RemotePort when UseConnection is set and the class is Active. |
116 | RemotePort cannot be zero when UseConnection is set. Please specify a valid service port number. |
117 | You cannot change UseConnection while the class is Active. |
118 | Message cannot be longer than MaxPacketSize. |
119 | Message is too short. |
434 | Unable to convert string to selected CodePage |
SSL Errors
270 | Cannot load specified security library. |
271 | Cannot open certificate store. |
272 | Cannot find specified certificate. |
273 | Cannot acquire security credentials. |
274 | Cannot find certificate chain. |
275 | Cannot verify certificate chain. |
276 | Error during handshake. |
280 | Error verifying certificate. |
281 | Could not find client certificate. |
282 | Could not find server certificate. |
283 | Error encrypting data. |
284 | Error decrypting data. |
TCP/IP Errors
10004 | [10004] Interrupted system call. |
10009 | [10009] Bad file number. |
10013 | [10013] Access denied. |
10014 | [10014] Bad address. |
10022 | [10022] Invalid argument. |
10024 | [10024] Too many open files. |
10035 | [10035] Operation would block. |
10036 | [10036] Operation now in progress. |
10037 | [10037] Operation already in progress. |
10038 | [10038] Socket operation on nonsocket. |
10039 | [10039] Destination address required. |
10040 | [10040] Message is too long. |
10041 | [10041] Protocol wrong type for socket. |
10042 | [10042] Bad protocol option. |
10043 | [10043] Protocol is not supported. |
10044 | [10044] Socket type is not supported. |
10045 | [10045] Operation is not supported on socket. |
10046 | [10046] Protocol family is not supported. |
10047 | [10047] Address family is not supported by protocol family. |
10048 | [10048] Address already in use. |
10049 | [10049] Cannot assign requested address. |
10050 | [10050] Network is down. |
10051 | [10051] Network is unreachable. |
10052 | [10052] Net dropped connection or reset. |
10053 | [10053] Software caused connection abort. |
10054 | [10054] Connection reset by peer. |
10055 | [10055] No buffer space available. |
10056 | [10056] Socket is already connected. |
10057 | [10057] Socket is not connected. |
10058 | [10058] Cannot send after socket shutdown. |
10059 | [10059] Too many references, cannot splice. |
10060 | [10060] Connection timed out. |
10061 | [10061] Connection refused. |
10062 | [10062] Too many levels of symbolic links. |
10063 | [10063] File name is too long. |
10064 | [10064] Host is down. |
10065 | [10065] No route to host. |
10066 | [10066] Directory is not empty |
10067 | [10067] Too many processes. |
10068 | [10068] Too many users. |
10069 | [10069] Disc Quota Exceeded. |
10070 | [10070] Stale NFS file handle. |
10071 | [10071] Too many levels of remote in path. |
10091 | [10091] Network subsystem is unavailable. |
10092 | [10092] WINSOCK DLL Version out of range. |
10093 | [10093] Winsock is not loaded yet. |
11001 | [11001] Host not found. |
11002 | [11002] Nonauthoritative 'Host not found' (try again or check DNS setup). |
11003 | [11003] Nonrecoverable errors: FORMERR, REFUSED, NOTIMP. |
11004 | [11004] Valid name, no data record (check DNS setup). |