AsyncUdpSocket.h

//
//  AsyncUdpSocket.h
//  
//  This class is in the public domain.
//  Originally created by Robbie Hanson on Wed Oct 01 2008.
//  Updated and maintained by Deusty Designs and the Mac development community.
//
//  http://code.google.com/p/cocoaasyncsocket/
//

#import <Foundation/Foundation.h>

@class AsyncSendPacket;
@class AsyncReceivePacket;

extern NSString *const AsyncUdpSocketException;
extern NSString *const AsyncUdpSocketErrorDomain;

enum AsyncUdpSocketError
{
	AsyncUdpSocketCFSocketError = kCFSocketError,	// From CFSocketError enum
	AsyncUdpSocketNoError = 0,                      // Never used
	AsyncUdpSocketBadParameter,                     // Used if given a bad parameter (such as an improper address)
	AsyncUdpSocketIPv4Unavailable,                  // Used if you bind/connect using IPv6 only
	AsyncUdpSocketIPv6Unavailable,                  // Used if you bind/connect using IPv4 only (or iPhone)
	AsyncUdpSocketSendTimeoutError,
	AsyncUdpSocketReceiveTimeoutError
};
typedef enum AsyncUdpSocketError AsyncUdpSocketError;

@interface AsyncUdpSocket : NSObject
{
	CFSocketRef theSocket4;            // IPv4 socket
	CFSocketRef theSocket6;            // IPv6 socket
	
	CFRunLoopSourceRef theSource4;     // For theSocket4
	CFRunLoopSourceRef theSource6;     // For theSocket6
	CFRunLoopRef theRunLoop;
	CFSocketContext theContext;
	NSArray *theRunLoopModes;
	
	NSMutableArray *theSendQueue;
	AsyncSendPacket *theCurrentSend;
	NSTimer *theSendTimer;
	
	NSMutableArray *theReceiveQueue;
	AsyncReceivePacket *theCurrentReceive;
	NSTimer *theReceiveTimer;
	
	id theDelegate;
	UInt16 theFlags;
	
	long theUserData;
	
	NSString *cachedLocalHost;
	UInt16 cachedLocalPort;
	
	NSString *cachedConnectedHost;
	UInt16 cachedConnectedPort;
	
	UInt32 maxReceiveBufferSize;
}

/**
 * Creates new instances of AsyncUdpSocket.
**/
- (id)init;
- (id)initWithDelegate:(id)delegate;
- (id)initWithDelegate:(id)delegate userData:(long)userData;

/**
 * Creates new instances of AsyncUdpSocket that support only IPv4 or IPv6.
 * The other init methods will support both, unless specifically binded or connected to one protocol.
 * If you know you'll only be using one protocol, these init methods may be a bit more efficient.
**/
- (id)initIPv4;
- (id)initIPv6;

- (id)delegate;
- (void)setDelegate:(id)delegate;

- (long)userData;
- (void)setUserData:(long)userData;

/**
 * Returns the local address info for the socket.
 * 
 * Note: Address info may not be available until after the socket has been bind'ed,
 * or until after data has been sent.
**/
- (NSString *)localHost;
- (UInt16)localPort;

/**
 * Returns the remote address info for the socket.
 * 
 * Note: Since UDP is connectionless by design, connected address info
 * will not be available unless the socket is explicitly connected to a remote host/port
**/
- (NSString *)connectedHost;
- (UInt16)connectedPort;

/**
 * Returns whether or not this socket has been connected to a single host.
 * By design, UDP is a connectionless protocol, and connecting is not needed.
 * If connected, the socket will only be able to send/receive data to/from the connected host.
**/
- (BOOL)isConnected;

/**
 * Returns whether or not this socket has been closed.
 * The only way a socket can be closed is if you explicitly call one of the close methods.
**/
- (BOOL)isClosed;

/**
 * Returns whether or not this socket supports IPv4.
 * By default this will be true, unless the socket is specifically initialized as IPv6 only,
 * or is binded or connected to an IPv6 address.
**/
- (BOOL)isIPv4;

/**
 * Returns whether or not this socket supports IPv6.
 * By default this will be true, unless the socket is specifically initialized as IPv4 only,
 * or is binded or connected to an IPv4 address.
 * 
 * This method will also return false on platforms that do not support IPv6.
 * Note: The iPhone does not currently support IPv6.
**/
- (BOOL)isIPv6;

/**
 * Returns the mtu of the socket.
 * If unknown, returns zero.
 * 
 * Sending data larger than this may result in an error.
 * This is an advanced topic, and one should understand the wide range of mtu's on networks and the internet.
 * Therefore this method is only for reference and may be of little use in many situations.
**/
- (unsigned int)maximumTransmissionUnit;

/**
 * Binds the UDP socket to the given port and optional address.
 * Binding should be done for server sockets that receive data prior to sending it.
 * Client sockets can skip binding,
 * as the OS will automatically assign the socket an available port when it starts sending data.
 * 
 * You cannot bind a socket after its been connected.
 * You can only bind a socket once.
 * You can still connect a socket (if desired) after binding.
 * 
 * On success, returns YES.
 * Otherwise returns NO, and sets errPtr. If you don't care about the error, you can pass nil for errPtr.
**/
- (BOOL)bindToPort:(UInt16)port error:(NSError **)errPtr;
- (BOOL)bindToAddress:(NSString *)localAddr port:(UInt16)port error:(NSError **)errPtr;

/**
 * Connects the UDP socket to the given host and port.
 * By design, UDP is a connectionless protocol, and connecting is not needed.
 * 
 * Choosing to connect to a specific host/port has the following effect:
 * - You will only be able to send data to the connected host/port.
 * - You will only be able to receive data from the connected host/port.
 * - You will receive ICMP messages that come from the connected host/port, such as "connection refused".
 * 
 * Connecting a UDP socket does not result in any communication on the socket.
 * It simply changes the internal state of the socket.
 * 
 * You cannot bind a socket after its been connected.
 * You can only connect a socket once.
 * 
 * On success, returns YES.
 * Otherwise returns NO, and sets errPtr. If you don't care about the error, you can pass nil for errPtr.
**/
- (BOOL)connectToHost:(NSString *)host onPort:(UInt16)port error:(NSError **)errPtr;
- (BOOL)connectToAddress:(NSData *)remoteAddr error:(NSError **)errPtr;

/**
 * Join multicast group
 *
 * Group should be an IP address (eg @"225.228.0.1")
**/
- (BOOL)joinMulticastGroup:(NSString *)group error:(NSError **)errPtr;
- (BOOL)joinMulticastGroup:(NSString *)group withAddress:(NSString *)interface error:(NSError **)errPtr;

/**
 * By default, the underlying socket in the OS will not allow you to send broadcast messages.
 * In order to send broadcast messages, you need to enable this functionality in the socket.
 * 
 * A broadcast is a UDP message to addresses like "192.168.255.255" or "255.255.255.255" that is
 * delivered to every host on the network.
 * The reason this is generally disabled by default is to prevent
 * accidental broadcast messages from flooding the network.
**/
- (BOOL)enableBroadcast:(BOOL)flag error:(NSError **)errPtr;

/**
 * Asynchronously sends the given data, with the given timeout and tag.
 * 
 * This method may only be used with a connected socket.
 * 
 * If data is nil or zero-length, this method does nothing and immediately returns NO.
 * If the socket is not connected, this method does nothing and immediately returns NO.
**/
- (BOOL)sendData:(NSData *)data withTimeout:(NSTimeInterval)timeout tag:(long)tag;

/**
 * Asynchronously sends the given data, with the given timeout and tag, to the given host and port.
 * 
 * This method cannot be used with a connected socket.
 * 
 * If data is nil or zero-length, this method does nothing and immediately returns NO.
 * If the socket is connected, this method does nothing and immediately returns NO.
 * If unable to resolve host to a valid IPv4 or IPv6 address, this method returns NO.
**/
- (BOOL)sendData:(NSData *)data toHost:(NSString *)host port:(UInt16)port withTimeout:(NSTimeInterval)timeout tag:(long)tag;

/**
 * Asynchronously sends the given data, with the given timeout and tag, to the given address.
 * 
 * This method cannot be used with a connected socket.
 * 
 * If data is nil or zero-length, this method does nothing and immediately returns NO.
 * If the socket is connected, this method does nothing and immediately returns NO.
**/
- (BOOL)sendData:(NSData *)data toAddress:(NSData *)remoteAddr withTimeout:(NSTimeInterval)timeout tag:(long)tag;

/**
 * Asynchronously receives a single datagram packet.
 * 
 * If the receive succeeds, the onUdpSocket:didReceiveData:fromHost:port:tag delegate method will be called.
 * Otherwise, a timeout will occur, and the onUdpSocket:didNotReceiveDataWithTag: delegate method will be called.
**/
- (void)receiveWithTimeout:(NSTimeInterval)timeout tag:(long)tag;

/**
 * Closes the socket immediately. Any pending send or receive operations are dropped.
**/
- (void)close;

/**
 * Closes after all pending send operations have completed.
 * After calling this, the sendData: and receive: methods will do nothing.
 * In other words, you won't be able to add any more send or receive operations to the queue.
 * The socket will close even if there are still pending receive operations.
**/
- (void)closeAfterSending;

/**
 * Closes after all pending receive operations have completed.
 * After calling this, the sendData: and receive: methods will do nothing.
 * In other words, you won't be able to add any more send or receive operations to the queue.
 * The socket will close even if there are still pending send operations.
**/
- (void)closeAfterReceiving;

/**
 * Closes after all pending send and receive operations have completed.
 * After calling this, the sendData: and receive: methods will do nothing.
 * In other words, you won't be able to add any more send or receive operations to the queue.
**/
- (void)closeAfterSendingAndReceiving;

/**
 * Gets/Sets the maximum size of the buffer that will be allocated for receive operations.
 * The default size is 9216 bytes.
 * 
 * The theoretical maximum size of any IPv4 UDP packet is UINT16_MAX = 65535.
 * The theoretical maximum size of any IPv6 UDP packet is UINT32_MAX = 4294967295.
 * 
 * In practice, however, the size of UDP packets will be much smaller.
 * Indeed most protocols will send and receive packets of only a few bytes,
 * or will set a limit on the size of packets to prevent fragmentation in the IP layer.
 * 
 * If you set the buffer size too small, the sockets API in the OS will silently discard
 * any extra data, and you will not be notified of the error.
**/
- (UInt32)maxReceiveBufferSize;
- (void)setMaxReceiveBufferSize:(UInt32)max;

/**
 * When you create an AsyncUdpSocket, it is added to the runloop of the current thread.
 * So it is easiest to simply create the socket on the thread you intend to use it.
 * 
 * If, however, you need to move the socket to a separate thread at a later time, this
 * method may be used to accomplish the task.
 * 
 * This method must be called from the thread/runloop the socket is currently running on.
 * 
 * Note: After calling this method, all further method calls to this object should be done from the given runloop.
 * Also, all delegate calls will be sent on the given runloop.
**/
- (BOOL)moveToRunLoop:(NSRunLoop *)runLoop;

/**
 * Allows you to configure which run loop modes the socket uses.
 * The default set of run loop modes is NSDefaultRunLoopMode.
 * 
 * If you'd like your socket to continue operation during other modes, you may want to add modes such as
 * NSModalPanelRunLoopMode or NSEventTrackingRunLoopMode. Or you may simply want to use NSRunLoopCommonModes.
 * 
 * Note: NSRunLoopCommonModes is defined in 10.5. For previous versions one can use kCFRunLoopCommonModes.
**/
- (BOOL)setRunLoopModes:(NSArray *)runLoopModes;

/**
 * Returns the current run loop modes the AsyncSocket instance is operating in.
 * The default set of run loop modes is NSDefaultRunLoopMode.
**/
- (NSArray *)runLoopModes;

@end

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
#pragma mark -
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

@protocol AsyncUdpSocketDelegate
@optional

/**
 * Called when the datagram with the given tag has been sent.
**/
- (void)onUdpSocket:(AsyncUdpSocket *)sock didSendDataWithTag:(long)tag;

/**
 * Called if an error occurs while trying to send a datagram.
 * This could be due to a timeout, or something more serious such as the data being too large to fit in a sigle packet.
**/
- (void)onUdpSocket:(AsyncUdpSocket *)sock didNotSendDataWithTag:(long)tag dueToError:(NSError *)error;

/**
 * Called when the socket has received the requested datagram.
 * 
 * Due to the nature of UDP, you may occasionally receive undesired packets.
 * These may be rogue UDP packets from unknown hosts,
 * or they may be delayed packets arriving after retransmissions have already occurred.
 * It's important these packets are properly ignored, while not interfering with the flow of your implementation.
 * As an aid, this delegate method has a boolean return value.
 * If you ever need to ignore a received packet, simply return NO,
 * and AsyncUdpSocket will continue as if the packet never arrived.
 * That is, the original receive request will still be queued, and will still timeout as usual if a timeout was set.
 * For example, say you requested to receive data, and you set a timeout of 500 milliseconds, using a tag of 15.
 * If rogue data arrives after 250 milliseconds, this delegate method would be invoked, and you could simply return NO.
 * If the expected data then arrives within the next 250 milliseconds,
 * this delegate method will be invoked, with a tag of 15, just as if the rogue data never appeared.
 * 
 * Under normal circumstances, you simply return YES from this method.
**/
- (BOOL)onUdpSocket:(AsyncUdpSocket *)sock
     didReceiveData:(NSData *)data
            withTag:(long)tag
           fromHost:(NSString *)host
               port:(UInt16)port;

/**
 * Called if an error occurs while trying to receive a requested datagram.
 * This is generally due to a timeout, but could potentially be something else if some kind of OS error occurred.
**/
- (void)onUdpSocket:(AsyncUdpSocket *)sock didNotReceiveDataWithTag:(long)tag dueToError:(NSError *)error;

/**
 * Called when the socket is closed.
 * A socket is only closed if you explicitly call one of the close methods.
**/
- (void)onUdpSocketDidClose:(AsyncUdpSocket *)sock;

@end