TCPServer.m

/*

File: TCPServer.m
Abstract: A TCP server that listens on an arbitrary port.

Version: 1.5

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*/

#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <CFNetwork/CFSocketStream.h>

#import "TCPServer.h"

NSString * const TCPServerErrorDomain = @"TCPServerErrorDomain";

@interface TCPServer ()
@property(nonatomic,retain) NSNetService* netService;
@property(assign) uint16_t port;
@end

@implementation TCPServer

@synthesize delegate=_delegate, netService=_netService, port=_port;

- (id)init {
    return self;
}

- (void)dealloc {
    [self stop];
    [super dealloc];
}

- (void)handleNewConnectionFromAddress:(NSData *)addr inputStream:(NSInputStream *)istr outputStream:(NSOutputStream *)ostr {
    // if the delegate implements the delegate method, call it  
    if (self.delegate && [self.delegate respondsToSelector:@selector(didAcceptConnectionForServer:inputStream:outputStream:)]) { 
        [self.delegate didAcceptConnectionForServer:self inputStream:istr outputStream:ostr];
    }
}

// This function is called by CFSocket when a new connection comes in.
// We gather some data here, and convert the function call to a method
// invocation on TCPServer.
static void TCPServerAcceptCallBack(CFSocketRef socket, CFSocketCallBackType type, CFDataRef address, const void *data, void *info) {
    TCPServer *server = (TCPServer *)info;
    if (kCFSocketAcceptCallBack == type) { 
        // for an AcceptCallBack, the data parameter is a pointer to a CFSocketNativeHandle
        CFSocketNativeHandle nativeSocketHandle = *(CFSocketNativeHandle *)data;
        uint8_t name[SOCK_MAXADDRLEN];
        socklen_t namelen = sizeof(name);
        NSData *peer = nil;
        if (0 == getpeername(nativeSocketHandle, (struct sockaddr *)name, &namelen)) {
            peer = [NSData dataWithBytes:name length:namelen];
        }
        CFReadStreamRef readStream = NULL;
		CFWriteStreamRef writeStream = NULL;
        CFStreamCreatePairWithSocket(kCFAllocatorDefault, nativeSocketHandle, &readStream, &writeStream);
        if (readStream && writeStream) {
            CFReadStreamSetProperty(readStream, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
            CFWriteStreamSetProperty(writeStream, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
            [server handleNewConnectionFromAddress:peer inputStream:(NSInputStream *)readStream outputStream:(NSOutputStream *)writeStream];
        } else {
            // on any failure, need to destroy the CFSocketNativeHandle 
            // since we are not going to use it any more
            close(nativeSocketHandle);
        }
        if (readStream) CFRelease(readStream);
        if (writeStream) CFRelease(writeStream);
    }
}

- (BOOL)start:(NSError **)error {
    CFSocketContext socketCtxt = {0, self, NULL, NULL, NULL};
    _ipv4socket = CFSocketCreate(kCFAllocatorDefault, PF_INET, SOCK_STREAM, IPPROTO_TCP, kCFSocketAcceptCallBack, (CFSocketCallBack)&TCPServerAcceptCallBack, &socketCtxt);
	
    if (NULL == _ipv4socket) {
        if (error) *error = [[NSError alloc] initWithDomain:TCPServerErrorDomain code:kTCPServerNoSocketsAvailable userInfo:nil];
        if (_ipv4socket) CFRelease(_ipv4socket);
        _ipv4socket = NULL;
        return NO;
    }
	
	
    int yes = 1;
    setsockopt(CFSocketGetNative(_ipv4socket), SOL_SOCKET, SO_REUSEADDR, (void *)&yes, sizeof(yes));
	
    // set up the IPv4 endpoint; use port 0, so the kernel will choose an arbitrary port for us, which will be advertised using Bonjour
    struct sockaddr_in addr4;
    memset(&addr4, 0, sizeof(addr4));
    addr4.sin_len = sizeof(addr4);
    addr4.sin_family = AF_INET;
    addr4.sin_port = 0;
    addr4.sin_addr.s_addr = htonl(INADDR_ANY);
    NSData *address4 = [NSData dataWithBytes:&addr4 length:sizeof(addr4)];
	
    if (kCFSocketSuccess != CFSocketSetAddress(_ipv4socket, (CFDataRef)address4)) {
        if (error) *error = [[NSError alloc] initWithDomain:TCPServerErrorDomain code:kTCPServerCouldNotBindToIPv4Address userInfo:nil];
        if (_ipv4socket) CFRelease(_ipv4socket);
        _ipv4socket = NULL;
        return NO;
    }
    
	// now that the binding was successful, we get the port number 
	// -- we will need it for the NSNetService
	NSData *addr = [(NSData *)CFSocketCopyAddress(_ipv4socket) autorelease];
	memcpy(&addr4, [addr bytes], [addr length]);
	self.port = ntohs(addr4.sin_port);
	
	
    // set up the run loop sources for the sockets
    CFRunLoopRef cfrl = CFRunLoopGetCurrent();
    CFRunLoopSourceRef source4 = CFSocketCreateRunLoopSource(kCFAllocatorDefault, _ipv4socket, 0);
    CFRunLoopAddSource(cfrl, source4, kCFRunLoopCommonModes);
    CFRelease(source4);
	
	
    return YES;
}

- (BOOL)stop {
    [self disableBonjour];

	if (_ipv4socket) {
		CFSocketInvalidate(_ipv4socket);
		CFRelease(_ipv4socket);
		_ipv4socket = NULL;
	}
	
	
    return YES;
}

- (BOOL) enableBonjourWithDomain:(NSString*)domain applicationProtocol:(NSString*)protocol name:(NSString*)name
{
	if(![domain length])
		domain = @""; //Will use default Bonjour registration doamins, typically just ".local"
	if(![name length])
		name = @""; //Will use default Bonjour name, e.g. the name assigned to the device in iTunes
	
	if(!protocol || ![protocol length] || _ipv4socket == NULL)
		return NO;
	

	self.netService = [[NSNetService alloc] initWithDomain:domain type:protocol name:name port:self.port];
	if(self.netService == nil)
		return NO;
	
	[self.netService scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
	[self.netService publish];
	[self.netService setDelegate:self];
	
	return YES;
}

/*
 Bonjour will not allow conflicting service instance names (in the same domain), and may have automatically renamed
 the service if there was a conflict.  We pass the name back to the delegate so that the name can be displayed to
 the user.
 See http://developer.apple.com/networking/bonjour/faq.html for more information.
 */

- (void)netServiceDidPublish:(NSNetService *)sender
{
    if (self.delegate && [self.delegate respondsToSelector:@selector(serverDidEnableBonjour:withName:)])
		[self.delegate serverDidEnableBonjour:self withName:sender.name];
}

- (void)netService:(NSNetService *)sender didNotPublish:(NSDictionary *)errorDict
{
	[super netServiceDidPublish:sender];
	if(self.delegate && [self.delegate respondsToSelector:@selector(server:didNotEnableBonjour:)])
		[self.delegate server:self didNotEnableBonjour:errorDict];
}

- (void) disableBonjour
{
	if(self.netService) {
		[self.netService stop];
		[self.netService removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
		self.netService = nil;
	}
}

- (NSString*) description
{
	return [NSString stringWithFormat:@"<%@ = 0x%08X | port %d | netService = %@>", [self class], (long)self, self.port, self.netService];
}

+ (NSString*) bonjourTypeFromIdentifier:(NSString*)identifier {
	if (![identifier length])
		return nil;
    
    return [NSString stringWithFormat:@"_%@._tcp.", identifier];
}

@end