//
// GCDAsyncUdpSocket
//
// This class is in the public domain.
// Originally created by Robbie Hanson of Deusty LLC.
// Updated and maintained by Deusty LLC and the Apple development community.
//
// https://github.com/robbiehanson/CocoaAsyncSocket
//
#import <Foundation/Foundation.h>
#import <dispatch/dispatch.h>
#import <TargetConditionals.h>
#import <Availability.h>
NS_ASSUME_NONNULL_BEGIN
extern NSString *const GCDAsyncUdpSocketException;
extern NSString *const GCDAsyncUdpSocketErrorDomain;
extern NSString *const GCDAsyncUdpSocketQueueName;
extern NSString *const GCDAsyncUdpSocketThreadName;
typedef NS_ERROR_ENUM(GCDAsyncUdpSocketErrorDomain, GCDAsyncUdpSocketError) {
GCDAsyncUdpSocketNoError = 0, // Never used
GCDAsyncUdpSocketBadConfigError, // Invalid configuration
GCDAsyncUdpSocketBadParamError, // Invalid parameter was passed
GCDAsyncUdpSocketSendTimeoutError, // A send operation timed out
GCDAsyncUdpSocketClosedError, // The socket was closed
GCDAsyncUdpSocketOtherError, // Description provided in userInfo
};
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
#pragma mark -
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
@class GCDAsyncUdpSocket;
@protocol GCDAsyncUdpSocketDelegate <NSObject>
@optional
/**
* By design, UDP is a connectionless protocol, and connecting is not needed.
* However, you may optionally choose to connect to a particular host for reasons
* outlined in the documentation for the various connect methods listed above.
*
* This method is called if one of the connect methods are invoked, and the connection is successful.
**/
- (void)udpSocket:(GCDAsyncUdpSocket *)sock didConnectToAddress:(NSData *)address;
/**
* By design, UDP is a connectionless protocol, and connecting is not needed.
* However, you may optionally choose to connect to a particular host for reasons
* outlined in the documentation for the various connect methods listed above.
*
* This method is called if one of the connect methods are invoked, and the connection fails.
* This may happen, for example, if a domain name is given for the host and the domain name is unable to be resolved.
**/
- (void)udpSocket:(GCDAsyncUdpSocket *)sock didNotConnect:(NSError * _Nullable)error;
/**
* Called when the datagram with the given tag has been sent.
**/
- (void)udpSocket:(GCDAsyncUdpSocket *)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)udpSocket:(GCDAsyncUdpSocket *)sock didNotSendDataWithTag:(long)tag dueToError:(NSError * _Nullable)error;
/**
* Called when the socket has received the requested datagram.
**/
- (void)udpSocket:(GCDAsyncUdpSocket *)sock didReceiveData:(NSData *)data
fromAddress:(NSData *)address
withFilterContext:(nullable id)filterContext;
/**
* Called when the socket is closed.
**/
- (void)udpSocketDidClose:(GCDAsyncUdpSocket *)sock withError:(NSError * _Nullable)error;
@end
/**
* You may optionally set a receive filter for the socket.
* A filter can provide several useful features:
*
* 1. Many times udp packets need to be parsed.
* Since the filter can run in its own independent queue, you can parallelize this parsing quite easily.
* The end result is a parallel socket io, datagram parsing, and packet processing.
*
* 2. Many times udp packets are discarded because they are duplicate/unneeded/unsolicited.
* The filter can prevent such packets from arriving at the delegate.
* And because the filter can run in its own independent queue, this doesn't slow down the delegate.
*
* - Since the udp protocol does not guarantee delivery, udp packets may be lost.
* Many protocols built atop udp thus provide various resend/re-request algorithms.
* This sometimes results in duplicate packets arriving.
* A filter may allow you to architect the duplicate detection code to run in parallel to normal processing.
*
* - Since the udp socket may be connectionless, its possible for unsolicited packets to arrive.
* Such packets need to be ignored.
*
* 3. Sometimes traffic shapers are needed to simulate real world environments.
* A filter allows you to write custom code to simulate such environments.
* The ability to code this yourself is especially helpful when your simulated environment
* is more complicated than simple traffic shaping (e.g. simulating a cone port restricted router),
* or the system tools to handle this aren't available (e.g. on a mobile device).
*
* @param data - The packet that was received.
* @param address - The address the data was received from.
* See utilities section for methods to extract info from address.
* @param context - Out parameter you may optionally set, which will then be passed to the delegate method.
* For example, filter block can parse the data and then,
* pass the parsed data to the delegate.
*
* @returns - YES if the received packet should be passed onto the delegate.
* NO if the received packet should be discarded, and not reported to the delegete.
*
* Example:
*
* GCDAsyncUdpSocketReceiveFilterBlock filter = ^BOOL (NSData *data, NSData *address, id *context) {
*
* MyProtocolMessage *msg = [MyProtocol parseMessage:data];
*
* *context = response;
* return (response != nil);
* };
* [udpSocket setReceiveFilter:filter withQueue:myParsingQueue];
*
**/
typedef BOOL (^GCDAsyncUdpSocketReceiveFilterBlock)(NSData *data, NSData *address, id __nullable * __nonnull context);
/**
* You may optionally set a send filter for the socket.
* A filter can provide several interesting possibilities:
*
* 1. Optional caching of resolved addresses for domain names.
* The cache could later be consulted, resulting in fewer system calls to getaddrinfo.
*
* 2. Reusable modules of code for bandwidth monitoring.
*
* 3. Sometimes traffic shapers are needed to simulate real world environments.
* A filter allows you to write custom code to simulate such environments.
* The ability to code this yourself is especially helpful when your simulated environment
* is more complicated than simple traffic shaping (e.g. simulating a cone port restricted router),
* or the system tools to handle this aren't available (e.g. on a mobile device).
*
* @param data - The packet that was received.
* @param address - The address the data was received from.
* See utilities section for methods to extract info from address.
* @param tag - The tag that was passed in the send method.
*
* @returns - YES if the packet should actually be sent over the socket.
* NO if the packet should be silently dropped (not sent over the socket).
*
* Regardless of the return value, the delegate will be informed that the packet was successfully sent.
*
**/
typedef BOOL (^GCDAsyncUdpSocketSendFilterBlock)(NSData *data, NSData *address, long tag);
@interface GCDAsyncUdpSocket : NSObject
/**
* GCDAsyncUdpSocket uses the standard delegate paradigm,
* but executes all delegate callbacks on a given delegate dispatch queue.
* This allows for maximum concurrency, while at the same time providing easy thread safety.
*
* You MUST set a delegate AND delegate dispatch queue before attempting to
* use the socket, or you will get an error.
*
* The socket queue is optional.
* If you pass NULL, GCDAsyncSocket will automatically create its own socket queue.
* If you choose to provide a socket queue, the socket queue must not be a concurrent queue,
* then please see the discussion for the method markSocketQueueTargetQueue.
*
* The delegate queue and socket queue can optionally be the same.
**/
- (instancetype)init;
- (instancetype)initWithSocketQueue:(nullable dispatch_queue_t)sq;
- (instancetype)initWithDelegate:(nullable id<GCDAsyncUdpSocketDelegate>)aDelegate delegateQueue:(nullable dispatch_queue_t)dq;
- (instancetype)initWithDelegate:(nullable id<GCDAsyncUdpSocketDelegate>)aDelegate delegateQueue:(nullable dispatch_queue_t)dq socketQueue:(nullable dispatch_queue_t)sq NS_DESIGNATED_INITIALIZER;
#pragma mark Configuration
- (nullable id<GCDAsyncUdpSocketDelegate>)delegate;
- (void)setDelegate:(nullable id<GCDAsyncUdpSocketDelegate>)delegate;
- (void)synchronouslySetDelegate:(nullable id<GCDAsyncUdpSocketDelegate>)delegate;
- (nullable dispatch_queue_t)delegateQueue;
- (void)setDelegateQueue:(nullable dispatch_queue_t)delegateQueue;
- (void)synchronouslySetDelegateQueue:(nullable dispatch_queue_t)delegateQueue;
- (void)getDelegate:(id<GCDAsyncUdpSocketDelegate> __nullable * __nullable)delegatePtr delegateQueue:(dispatch_queue_t __nullable * __nullable)delegateQueuePtr;
- (void)setDelegate:(nullable id<GCDAsyncUdpSocketDelegate>)delegate delegateQueue:(nullable dispatch_queue_t)delegateQueue;
- (void)synchronouslySetDelegate:(nullable id<GCDAsyncUdpSocketDelegate>)delegate delegateQueue:(nullable dispatch_queue_t)delegateQueue;
/**
* By default, both IPv4 and IPv6 are enabled.
*
* This means GCDAsyncUdpSocket automatically supports both protocols,
* and can send to IPv4 or IPv6 addresses,
* as well as receive over IPv4 and IPv6.
*
* For operations that require DNS resolution, GCDAsyncUdpSocket supports both IPv4 and IPv6.
* If a DNS lookup returns only IPv4 results, GCDAsyncUdpSocket will automatically use IPv4.
* If a DNS lookup returns only IPv6 results, GCDAsyncUdpSocket will automatically use IPv6.
* If a DNS lookup returns both IPv4 and IPv6 results, then the protocol used depends on the configured preference.
* If IPv4 is preferred, then IPv4 is used.
* If IPv6 is preferred, then IPv6 is used.
* If neutral, then the first IP version in the resolved array will be used.
*
* Starting with Mac OS X 10.7 Lion and iOS 5, the default IP preference is neutral.
* On prior systems the default IP preference is IPv4.
**/
- (BOOL)isIPv4Enabled;
- (void)setIPv4Enabled:(BOOL)flag;
- (BOOL)isIPv6Enabled;
- (void)setIPv6Enabled:(BOOL)flag;
- (BOOL)isIPv4Preferred;
- (BOOL)isIPv6Preferred;
- (BOOL)isIPVersionNeutral;
- (void)setPreferIPv4;
- (void)setPreferIPv6;
- (void)setIPVersionNeutral;
/**
* Gets/Sets the maximum size of the buffer that will be allocated for receive operations.
* The default maximum size is 65535 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.
*
* Since the OS/GCD notifies us of the size of each received UDP packet,
* the actual allocated buffer size for each packet is exact.
* And in practice the size of UDP packets is generally much smaller than the max.
* 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.
**/
- (uint16_t)maxReceiveIPv4BufferSize;
- (void)setMaxReceiveIPv4BufferSize:(uint16_t)max;
- (uint32_t)maxReceiveIPv6BufferSize;
- (void)setMaxReceiveIPv6BufferSize:(uint32_t)max;
/**
* Gets/Sets the maximum size of the buffer that will be allocated for send operations.
* The default maximum size is 65535 bytes.
*
* Given that a typical link MTU is 1500 bytes, a large UDP datagram will have to be
* fragmented, and that’s both expensive and risky (if one fragment goes missing, the
* entire datagram is lost). You are much better off sending a large number of smaller
* UDP datagrams, preferably using a path MTU algorithm to avoid fragmentation.
*
* You must set it before the sockt is created otherwise it won't work.
*
**/
- (uint16_t)maxSendBufferSize;
- (void)setMaxSendBufferSize:(uint16_t)max;
/**
* User data allows you to associate arbitrary information with the socket.
* This data is not used internally in any way.
**/
- (nullable id)userData;
- (void)setUserData:(nullable id)arbitraryUserData;
#pragma mark Diagnostics
/**
* Returns the local address info for the socket.
*
* The localAddress method returns a sockaddr structure wrapped in a NSData object.
* The localHost method returns the human readable IP address as a string.
*
* Note: Address info may not be available until after the socket has been binded, connected
* or until after data has been sent.
**/
- (nullable NSData *)localAddress;
- (nullable NSString *)localHost;
- (uint16_t)localPort;
- (nullable NSData *)localAddress_IPv4;
- (nullable NSString *)localHost_IPv4;
- (uint16_t)localPort_IPv4;
- (nullable NSData *)localAddress_IPv6;
- (nullable NSString *)localHost_IPv6;
- (uint16_t)localPort_IPv6;
/**
* Returns the remote address info for the socket.
*
* The connectedAddress method returns a sockaddr structure wrapped in a NSData object.
* The connectedHost method returns the human readable IP address as a string.
*
* 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.
* If the socket is not connected, these methods will return nil / 0.
**/
- (nullable NSData *)connectedAddress;
- (nullable NSString *)connectedHost;
- (uint16_t)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 is IPv4.
*
* By default this will be true, unless:
* - IPv4 is disabled (via setIPv4Enabled:)
* - The socket is explicitly bound to an IPv6 address
* - The socket is connected to an IPv6 address
**/
- (BOOL)isIPv4;
/**
* Returns whether or not this socket is IPv6.
*
* By default this will be true, unless:
* - IPv6 is disabled (via setIPv6Enabled:)
* - The socket is explicitly bound to an IPv4 address
* _ The socket is 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;
#pragma mark Binding
/**
* Binds the UDP socket to the given port.
* 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 may optionally pass a port number of zero to immediately bind the socket,
* yet still allow the OS to automatically assign an available port.
*
* 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 NULL for errPtr.
**/
- (BOOL)bindToPort:(uint16_t)port error:(NSError **)errPtr;
/**
* Binds the UDP socket to the given port and optional interface.
* 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 may optionally pass a port number of zero to immediately bind the socket,
* yet still allow the OS to automatically assign an available port.
*
* The interface may be a name (e.g. "en1" or "lo0") or the corresponding IP address (e.g. "192.168.4.35").
* You may also use the special strings "localhost" or "loopback" to specify that
* the socket only accept packets from the local machine.
*
* 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 NULL for errPtr.
**/
- (BOOL)bindToPort:(uint16_t)port interface:(nullable NSString *)interface error:(NSError **)errPtr;
/**
* Binds the UDP socket to the given address, specified as a sockaddr structure wrapped in a NSData object.
*
* If you have an existing struct sockaddr you can convert it to a NSData object like so:
* struct sockaddr sa -> NSData *dsa = [NSData dataWithBytes:&remoteAddr length:remoteAddr.sa_len];
* struct sockaddr *sa -> NSData *dsa = [NSData dataWithBytes:remoteAddr length:remoteAddr->sa_len];
*
* 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 NULL for errPtr.
**/
- (BOOL)bindToAddress:(NSData *)localAddr error:(NSError **)errPtr;
#pragma mark Connecting
/**
* 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".
*
* The actual process of 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 it has been connected.
* You can only connect a socket once.
*
* The host may be a domain name (e.g. "deusty.com") or an IP address string (e.g. "192.168.0.2").
*
* This method is asynchronous as it requires a DNS lookup to resolve the given host name.
* If an obvious error is detected, this method immediately returns NO and sets errPtr.
* If you don't care about the error, you can pass nil for errPtr.
* Otherwise, this method returns YES and begins the asynchronous connection process.
* The result of the asynchronous connection process will be reported via the delegate methods.
**/
- (BOOL)connectToHost:(NSString *)host onPort:(uint16_t)port error:(NSError **)errPtr;
/**
* Connects the UDP socket to the given address, specified as a sockaddr structure wrapped in a NSData object.
*
* If you have an existing struct sockaddr you can convert it to a NSData object like so:
* struct sockaddr sa -> NSData *dsa = [NSData dataWithBytes:&remoteAddr length:remoteAddr.sa_len];
* struct sockaddr *sa -> NSData *dsa = [NSData dataWithBytes:remoteAddr length:remoteAddr->sa_len];
*
* By design, UDP is a connectionless protocol, and connecting is not needed.
*
* Choosing to connect to a specific address has the following effect:
* - You will only be able to send data to the connected address.
* - You will only be able to receive data from the connected address.
* - You will receive ICMP messages that come from the connected address, 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.
*
* Note: Unlike the connectToHost:onPort:error: method, this method does not require a DNS lookup.
* Thus when this method returns, the connection has either failed or fully completed.
* In other words, this method is synchronous, unlike the asynchronous connectToHost::: method.
* However, for compatibility and simplification of delegate code, if this method returns YES
* then the corresponding delegate method (udpSocket:didConnectToHost:port:) is still invoked.
**/
- (BOOL)connectToAddress:(NSData *)remoteAddr error:(NSError **)errPtr;
#pragma mark Multicast
/**
* Join multicast group.
* Group should be an IP address (eg @"225.228.0.1").
*
* 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)joinMulticastGroup:(NSString *)group error:(NSError **)errPtr;
/**
* Join multicast group.
* Group should be an IP address (eg @"225.228.0.1").
* The interface may be a name (e.g. "en1" or "lo0") or the corresponding IP address (e.g. "192.168.4.35").
*
* 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)joinMulticastGroup:(NSString *)group onInterface:(nullable NSString *)interface error:(NSError **)errPtr;
- (BOOL)leaveMulticastGroup:(NSString *)group error:(NSError **)errPtr;
- (BOOL)leaveMulticastGroup:(NSString *)group onInterface:(nullable NSString *)interface error:(NSError **)errPtr;
/**
* Send multicast on a specified interface.
* For IPv4, interface should be the the IP address of the interface (eg @"192.168.10.1").
* For IPv6, interface should be the a network interface name (eg @"en0").
*
* 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)sendIPv4MulticastOnInterface:(NSString*)interface error:(NSError **)errPtr;
- (BOOL)sendIPv6MulticastOnInterface:(NSString*)interface error:(NSError **)errPtr;
#pragma mark Reuse Port
/**
* By default, only one socket can be bound to a given IP address + port at a time.
* To enable multiple processes to simultaneously bind to the same address+port,
* you need to enable this functionality in the socket. All processes that wish to
* use the address+port simultaneously must all enable reuse port on the socket
* bound to that port.
**/
- (BOOL)enableReusePort:(BOOL)flag error:(NSError **)errPtr;
#pragma mark Broadcast
/**
* 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 (by the OS) is to prevent
* accidental broadcast messages from flooding the network.
**/
- (BOOL)enableBroadcast:(BOOL)flag error:(NSError **)errPtr;
#pragma mark Sending
/**
* Asynchronously sends the given data, with the given timeout and tag.
*
* This method may only be used with a connected socket.
* Recall that connecting is optional for a UDP socket.
* For connected sockets, data can only be sent to the connected address.
* For non-connected sockets, the remote destination is specified for each packet.
* For more information about optionally connecting udp sockets, see the documentation for the connect methods above.
*
* @param data
* The data to send.
* If data is nil or zero-length, this method does nothing.
* If passing NSMutableData, please read the thread-safety notice below.
*
* @param timeout
* The timeout for the send opeartion.
* If the timeout value is negative, the send operation will not use a timeout.
*
* @param tag
* The tag is for your convenience.
* It is not sent or received over the socket in any manner what-so-ever.
* It is reported back as a parameter in the udpSocket:didSendDataWithTag:
* or udpSocket:didNotSendDataWithTag:dueToError: methods.
* You can use it as an array index, state id, type constant, etc.
*
*
* Thread-Safety Note:
* If the given data parameter is mutable (NSMutableData) then you MUST NOT alter the data while
* the socket is sending it. In other words, it's not safe to alter the data until after the delegate method
* udpSocket:didSendDataWithTag: or udpSocket:didNotSendDataWithTag:dueToError: is invoked signifying
* that this particular send operation has completed.
* This is due to the fact that GCDAsyncUdpSocket does NOT copy the data.
* It simply retains it for performance reasons.
* Often times, if NSMutableData is passed, it is because a request/response was built up in memory.
* Copying this data adds an unwanted/unneeded overhead.
* If you need to write data from an immutable buffer, and you need to alter the buffer before the socket
* completes sending the bytes (which is NOT immediately after this method returns, but rather at a later time
* when the delegate method notifies you), then you should first copy the bytes, and pass the copy to this method.
**/
- (void)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.
* Recall that connecting is optional for a UDP socket.
* For connected sockets, data can only be sent to the connected address.
* For non-connected sockets, the remote destination is specified for each packet.
* For more information about optionally connecting udp sockets, see the documentation for the connect methods above.
*
* @param data
* The data to send.
* If data is nil or zero-length, this method does nothing.
* If passing NSMutableData, please read the thread-safety notice below.
*
* @param host
* The destination to send the udp packet to.
* May be specified as a domain name (e.g. "deusty.com") or an IP address string (e.g. "192.168.0.2").
* You may also use the convenience strings of "loopback" or "localhost".
*
* @param port
* The port of the host to send to.
*
* @param timeout
* The timeout for the send opeartion.
* If the timeout value is negative, the send operation will not use a timeout.
*
* @param tag
* The tag is for your convenience.
* It is not sent or received over the socket in any manner what-so-ever.
* It is reported back as a parameter in the udpSocket:didSendDataWithTag:
* or udpSocket:didNotSendDataWithTag:dueToError: methods.
* You can use it as an array index, state id, type constant, etc.
*
*
* Thread-Safety Note:
* If the given data parameter is mutable (NSMutableData) then you MUST NOT alter the data while
* the socket is sending it. In other words, it's not safe to alter the data until after the delegate method
* udpSocket:didSendDataWithTag: or udpSocket:didNotSendDataWithTag:dueToError: is invoked signifying
* that this particular send operation has completed.
* This is due to the fact that GCDAsyncUdpSocket does NOT copy the data.
* It simply retains it for performance reasons.
* Often times, if NSMutableData is passed, it is because a request/response was built up in memory.
* Copying this data adds an unwanted/unneeded overhead.
* If you need to write data from an immutable buffer, and you need to alter the buffer before the socket
* completes sending the bytes (which is NOT immediately after this method returns, but rather at a later time
* when the delegate method notifies you), then you should first copy the bytes, and pass the copy to this method.
**/
- (void)sendData:(NSData *)data
toHost:(NSString *)host
port:(uint16_t)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.
* Recall that connecting is optional for a UDP socket.
* For connected sockets, data can only be sent to the connected address.
* For non-connected sockets, the remote destination is specified for each packet.
* For more information about optionally connecting udp sockets, see the documentation for the connect methods above.
*
* @param data
* The data to send.
* If data is nil or zero-length, this method does nothing.
* If passing NSMutableData, please read the thread-safety notice below.
*
* @param remoteAddr
* The address to send the data to (specified as a sockaddr structure wrapped in a NSData object).
*
* @param timeout
* The timeout for the send opeartion.
* If the timeout value is negative, the send operation will not use a timeout.
*
* @param tag
* The tag is for your convenience.
* It is not sent or received over the socket in any manner what-so-ever.
* It is reported back as a parameter in the udpSocket:didSendDataWithTag:
* or udpSocket:didNotSendDataWithTag:dueToError: methods.
* You can use it as an array index, state id, type constant, etc.
*
*
* Thread-Safety Note:
* If the given data parameter is mutable (NSMutableData) then you MUST NOT alter the data while
* the socket is sending it. In other words, it's not safe to alter the data until after the delegate method
* udpSocket:didSendDataWithTag: or udpSocket:didNotSendDataWithTag:dueToError: is invoked signifying
* that this particular send operation has completed.
* This is due to the fact that GCDAsyncUdpSocket does NOT copy the data.
* It simply retains it for performance reasons.
* Often times, if NSMutableData is passed, it is because a request/response was built up in memory.
* Copying this data adds an unwanted/unneeded overhead.
* If you need to write data from an immutable buffer, and you need to alter the buffer before the socket
* completes sending the bytes (which is NOT immediately after this method returns, but rather at a later time
* when the delegate method notifies you), then you should first copy the bytes, and pass the copy to this method.
**/
- (void)sendData:(NSData *)data toAddress:(NSData *)remoteAddr withTimeout:(NSTimeInterval)timeout tag:(long)tag;
/**
* You may optionally set a send filter for the socket.
* A filter can provide several interesting possibilities:
*
* 1. Optional caching of resolved addresses for domain names.
* The cache could later be consulted, resulting in fewer system calls to getaddrinfo.
*
* 2. Reusable modules of code for bandwidth monitoring.
*
* 3. Sometimes traffic shapers are needed to simulate real world environments.
* A filter allows you to write custom code to simulate such environments.
* The ability to code this yourself is especially helpful when your simulated environment
* is more complicated than simple traffic shaping (e.g. simulating a cone port restricted router),
* or the system tools to handle this aren't available (e.g. on a mobile device).
*
* For more information about GCDAsyncUdpSocketSendFilterBlock, see the documentation for its typedef.
* To remove a previously set filter, invoke this method and pass a nil filterBlock and NULL filterQueue.
*
* Note: This method invokes setSendFilter:withQueue:isAsynchronous: (documented below),
* passing YES for the isAsynchronous parameter.
**/
- (void)setSendFilter:(nullable GCDAsyncUdpSocketSendFilterBlock)filterBlock withQueue:(nullable dispatch_queue_t)filterQueue;
/**
* The receive filter can be run via dispatch_async or dispatch_sync.
* Most typical situations call for asynchronous operation.
*
* However, there are a few situations in which synchronous operation is preferred.
* Such is the case when the filter is extremely minimal and fast.
* This is because dispatch_sync is faster than dispatch_async.
*
* If you choose synchronous operation, be aware of possible deadlock conditions.
* Since the socket queue is executing your block via dispatch_sync,
* then you cannot perform any tasks which may invoke dispatch_sync on the socket queue.
* For example, you can't query properties on the socket.
**/
- (void)setSendFilter:(nullable GCDAsyncUdpSocketSendFilterBlock)filterBlock
withQueue:(nullable dispatch_queue_t)filterQueue
isAsynchronous:(BOOL)isAsynchronous;
#pragma mark Receiving
/**
* There are two modes of operation for receiving packets: one-at-a-time & continuous.
*
* In one-at-a-time mode, you call receiveOnce everytime your delegate is ready to process an incoming udp packet.
* Receiving packets one-at-a-time may be better suited for implementing certain state machine code,
* where your state machine may not always be ready to process incoming packets.
*
* In continuous mode, the delegate is invoked immediately everytime incoming udp packets are received.
* Receiving packets continuously is better suited to real-time streaming applications.
*
* You may switch back and forth between one-at-a-time mode and continuous mode.
* If the socket is currently in continuous mode, calling this method will switch it to one-at-a-time mode.
*
* When a packet is received (and not filtered by the optional receive filter),
* the delegate method (udpSocket:didReceiveData:fromAddress:withFilterContext:) is invoked.
*
* If the socket is able to begin receiving packets, this method returns YES.
* Otherwise it returns NO, and sets the errPtr with appropriate error information.
*
* An example error:
* You created a udp socket to act as a server, and immediately called receive.
* You forgot to first bind the socket to a port number, and received a error with a message like:
* "Must bind socket before you can receive data."
**/
- (BOOL)receiveOnce:(NSError **)errPtr;
/**
* There are two modes of operation for receiving packets: one-at-a-time & continuous.
*
* In one-at-a-time mode, you call receiveOnce everytime your delegate is ready to process an incoming udp packet.
* Receiving packets one-at-a-time may be better suited for implementing certain state machine code,
* where your state machine may not always be ready to process incoming packets.
*
* In continuous mode, the delegate is invoked immediately everytime incoming udp packets are received.
* Receiving packets continuously is better suited to real-time streaming applications.
*
* You may switch back and forth between one-at-a-time mode and continuous mode.
* If the socket is currently in one-at-a-time mode, calling this method will switch it to continuous mode.
*
* For every received packet (not filtered by the optional receive filter),
* the delegate method (udpSocket:didReceiveData:fromAddress:withFilterContext:) is invoked.
*
* If the socket is able to begin receiving packets, this method returns YES.
* Otherwise it returns NO, and sets the errPtr with appropriate error information.
*
* An example error:
* You created a udp socket to act as a server, and immediately called receive.
* You forgot to first bind the socket to a port number, and received a error with a message like:
* "Must bind socket before you can receive data."
**/
- (BOOL)beginReceiving:(NSError **)errPtr;
/**
* If the socket is currently receiving (beginReceiving has been called), this method pauses the receiving.
* That is, it won't read any more packets from the underlying OS socket until beginReceiving is called again.
*
* Important Note:
* GCDAsyncUdpSocket may be running in parallel with your code.
* That is, your delegate is likely running on a separate thread/dispatch_queue.
* When you invoke this method, GCDAsyncUdpSocket may have already dispatched delegate methods to be invoked.
* Thus, if those delegate methods have already been dispatch_async'd,
* your didReceive delegate method may still be invoked after this method has been called.
* You should be aware of this, and program defensively.
**/
- (void)pauseReceiving;
/**
* You may optionally set a receive filter for the socket.
* This receive filter may be set to run in its own queue (independent of delegate queue).
*
* A filter can provide several useful features.
*
* 1. Many times udp packets need to be parsed.
* Since the filter can run in its own independent queue, you can parallelize this parsing quite easily.
* The end result is a parallel socket io, datagram parsing, and packet processing.
*
* 2. Many times udp packets are discarded because they are duplicate/unneeded/unsolicited.
* The filter can prevent such packets from arriving at the delegate.
* And because the filter can run in its own independent queue, this doesn't slow down the delegate.
*
* - Since the udp protocol does not guarantee delivery, udp packets may be lost.
* Many protocols built atop udp thus provide various resend/re-request algorithms.
* This sometimes results in duplicate packets arriving.
* A filter may allow you to architect the duplicate detection code to run in parallel to normal processing.
*
* - Since the udp socket may be connectionless, its possible for unsolicited packets to arrive.
* Such packets need to be ignored.
*
* 3. Sometimes traffic shapers are needed to simulate real world environments.
* A filter allows you to write custom code to simulate such environments.
* The ability to code this yourself is especially helpful when your simulated environment
* is more complicated than simple traffic shaping (e.g. simulating a cone port restricted router),
* or the system tools to handle this aren't available (e.g. on a mobile device).
*
* Example:
*
* GCDAsyncUdpSocketReceiveFilterBlock filter = ^BOOL (NSData *data, NSData *address, id *context) {
*
* MyProtocolMessage *msg = [MyProtocol parseMessage:data];
*
* *context = response;
* return (response != nil);
* };
* [udpSocket setReceiveFilter:filter withQueue:myParsingQueue];
*
* For more information about GCDAsyncUdpSocketReceiveFilterBlock, see the documentation for its typedef.
* To remove a previously set filter, invoke this method and pass a nil filterBlock and NULL filterQueue.
*
* Note: This method invokes setReceiveFilter:withQueue:isAsynchronous: (documented below),
* passing YES for the isAsynchronous parameter.
**/
- (void)setReceiveFilter:(nullable GCDAsyncUdpSocketReceiveFilterBlock)filterBlock withQueue:(nullable dispatch_queue_t)filterQueue;
/**
* The receive filter can be run via dispatch_async or dispatch_sync.
* Most typical situations call for asynchronous operation.
*
* However, there are a few situations in which synchronous operation is preferred.
* Such is the case when the filter is extremely minimal and fast.
* This is because dispatch_sync is faster than dispatch_async.
*
* If you choose synchronous operation, be aware of possible deadlock conditions.
* Since the socket queue is executing your block via dispatch_sync,
* then you cannot perform any tasks which may invoke dispatch_sync on the socket queue.
* For example, you can't query properties on the socket.
**/
- (void)setReceiveFilter:(nullable GCDAsyncUdpSocketReceiveFilterBlock)filterBlock
withQueue:(nullable dispatch_queue_t)filterQueue
isAsynchronous:(BOOL)isAsynchronous;
#pragma mark Closing
/**
* Immediately closes the underlying socket.
* Any pending send operations are discarded.
*
* The GCDAsyncUdpSocket instance may optionally be used again.
* (it will setup/configure/use another unnderlying BSD socket).
**/
- (void)close;
/**
* Closes the underlying socket after all pending send operations have been sent.
*
* The GCDAsyncUdpSocket instance may optionally be used again.
* (it will setup/configure/use another unnderlying BSD socket).
**/
- (void)closeAfterSending;
#pragma mark Advanced
/**
* GCDAsyncSocket maintains thread safety by using an internal serial dispatch_queue.
* In most cases, the instance creates this queue itself.
* However, to allow for maximum flexibility, the internal queue may be passed in the init method.
* This allows for some advanced options such as controlling socket priority via target queues.
* However, when one begins to use target queues like this, they open the door to some specific deadlock issues.
*
* For example, imagine there are 2 queues:
* dispatch_queue_t socketQueue;
* dispatch_queue_t socketTargetQueue;
*
* If you do this (pseudo-code):
* socketQueue.targetQueue = socketTargetQueue;
*
* Then all socketQueue operations will actually get run on the given socketTargetQueue.
* This is fine and works great in most situations.
* But if you run code directly from within the socketTargetQueue that accesses the socket,
* you could potentially get deadlock. Imagine the following code:
*
* - (BOOL)socketHasSomething
* {
* __block BOOL result = NO;
* dispatch_block_t block = ^{
* result = [self someInternalMethodToBeRunOnlyOnSocketQueue];
* }
* if (is_executing_on_queue(socketQueue))
* block();
* else
* dispatch_sync(socketQueue, block);
*
* return result;
* }
*
* What happens if you call this method from the socketTargetQueue? The result is deadlock.
* This is because the GCD API offers no mechanism to discover a queue's targetQueue.
* Thus we have no idea if our socketQueue is configured with a targetQueue.
* If we had this information, we could easily avoid deadlock.
* But, since these API's are missing or unfeasible, you'll have to explicitly set it.
*
* IF you pass a socketQueue via the init method,
* AND you've configured the passed socketQueue with a targetQueue,
* THEN you should pass the end queue in the target hierarchy.
*
* For example, consider the following queue hierarchy:
* socketQueue -> ipQueue -> moduleQueue
*
* This example demonstrates priority shaping within some server.
* All incoming client connections from the same IP address are executed on the same target queue.
* And all connections for a particular module are executed on the same target queue.
* Thus, the priority of all networking for the entire module can be changed on the fly.
* Additionally, networking traffic from a single IP cannot monopolize the module.
*
* Here's how you would accomplish something like that:
* - (dispatch_queue_t)newSocketQueueForConnectionFromAddress:(NSData *)address onSocket:(GCDAsyncSocket *)sock
* {
* dispatch_queue_t socketQueue = dispatch_queue_create("", NULL);
* dispatch_queue_t ipQueue = [self ipQueueForAddress:address];
*
* dispatch_set_target_queue(socketQueue, ipQueue);
* dispatch_set_target_queue(iqQueue, moduleQueue);
*
* return socketQueue;
* }
* - (void)socket:(GCDAsyncSocket *)sock didAcceptNewSocket:(GCDAsyncSocket *)newSocket
* {
* [clientConnections addObject:newSocket];
* [newSocket markSocketQueueTargetQueue:moduleQueue];
* }
*
* Note: This workaround is ONLY needed if you intend to execute code directly on the ipQueue or moduleQueue.
* This is often NOT the case, as such queues are used solely for execution shaping.
**/
- (void)markSocketQueueTargetQueue:(dispatch_queue_t)socketQueuesPreConfiguredTargetQueue;
- (void)unmarkSocketQueueTargetQueue:(dispatch_queue_t)socketQueuesPreviouslyConfiguredTargetQueue;
/**
* It's not thread-safe to access certain variables from outside the socket's internal queue.
*
* For example, the socket file descriptor.
* File descriptors are simply integers which reference an index in the per-process file table.
* However, when one requests a new file descriptor (by opening a file or socket),
* the file descriptor returned is guaranteed to be the lowest numbered unused descriptor.
* So if we're not careful, the following could be possible:
*
* - Thread A invokes a method which returns the socket's file descriptor.
* - The socket is closed via the socket's internal queue on thread B.
* - Thread C opens a file, and subsequently receives the file descriptor that was previously the socket's FD.
* - Thread A is now accessing/altering the file instead of the socket.
*
* In addition to this, other variables are not actually objects,
* and thus cannot be retained/released or even autoreleased.
* An example is the sslContext, of type SSLContextRef, which is actually a malloc'd struct.
*
* Although there are internal variables that make it difficult to maintain thread-safety,
* it is important to provide access to these variables
* to ensure this class can be used in a wide array of environments.
* This method helps to accomplish this by invoking the current block on the socket's internal queue.
* The methods below can be invoked from within the block to access
* those generally thread-unsafe internal variables in a thread-safe manner.
* The given block will be invoked synchronously on the socket's internal queue.
*
* If you save references to any protected variables and use them outside the block, you do so at your own peril.
**/
- (void)performBlock:(dispatch_block_t)block;
/**
* These methods are only available from within the context of a performBlock: invocation.
* See the documentation for the performBlock: method above.
*
* Provides access to the socket's file descriptor(s).
* If the socket isn't connected, or explicity bound to a particular interface,
* it might actually have multiple internal socket file descriptors - one for IPv4 and one for IPv6.
**/
- (int)socketFD;
- (int)socket4FD;
- (int)socket6FD;
#if TARGET_OS_IPHONE
/**
* These methods are only available from within the context of a performBlock: invocation.
* See the documentation for the performBlock: method above.
*
* Returns (creating if necessary) a CFReadStream/CFWriteStream for the internal socket.
*
* Generally GCDAsyncUdpSocket doesn't use CFStream. (It uses the faster GCD API's.)
* However, if you need one for any reason,
* these methods are a convenient way to get access to a safe instance of one.
**/
- (nullable CFReadStreamRef)readStream;
- (nullable CFWriteStreamRef)writeStream;
/**
* This method is only available from within the context of a performBlock: invocation.
* See the documentation for the performBlock: method above.
*
* Configures the socket to allow it to operate when the iOS application has been backgrounded.
* In other words, this method creates a read & write stream, and invokes:
*
* CFReadStreamSetProperty(readStream, kCFStreamNetworkServiceType, kCFStreamNetworkServiceTypeVoIP);
* CFWriteStreamSetProperty(writeStream, kCFStreamNetworkServiceType, kCFStreamNetworkServiceTypeVoIP);
*
* Returns YES if successful, NO otherwise.
*
* Example usage:
*
* [asyncUdpSocket performBlock:^{
* [asyncUdpSocket enableBackgroundingOnSocket];
* }];
*
*
* NOTE : Apple doesn't currently support backgrounding UDP sockets. (Only TCP for now).
**/
//- (BOOL)enableBackgroundingOnSockets;
#endif
#pragma mark Utilities
/**
* Extracting host/port/family information from raw address data.
**/
+ (nullable NSString *)hostFromAddress:(NSData *)address;
+ (uint16_t)portFromAddress:(NSData *)address;
+ (int)familyFromAddress:(NSData *)address;
+ (BOOL)isIPv4Address:(NSData *)address;
+ (BOOL)isIPv6Address:(NSData *)address;
+ (BOOL)getHost:(NSString * __nullable * __nullable)hostPtr port:(uint16_t * __nullable)portPtr fromAddress:(NSData *)address;
+ (BOOL)getHost:(NSString * __nullable * __nullable)hostPtr port:(uint16_t * __nullable)portPtr family:(int * __nullable)afPtr fromAddress:(NSData *)address;
@end
NS_ASSUME_NONNULL_END