http://www.cocoachina.com/industry/20130830/6904.html

客户端： 

导入头文件： 
#import <sys/socket.h> 
#import <netinet/in.h> 
#import <arpa/inet.h> 
#import <unistd.h> 
 
1. 创建连接 
CFSocketContext sockContext = {0, // 结构体的版本，必须为0 
self,  // 一个任意指针的数据，可以用在创建时CFSocket对象相关联。这个指针被传递给所有的上下文中定义的回调。 
NULL, // 一个定义在上面指针中的retain的回调， 可以为NULL 
NULL, NULL}; 
 
CFSocketRef _socket = (kCFAllocatorDefault, // 为新对象分配内存，可以为nil 
PF_INET, // 协议族，如果为0或者负数，则默认为PF_INET 
SOCK_STREAM, // 套接字类型，如果协议族为PF_INET,则它会默认为SOCK_STREAM 
IPPROTO_TCP, // 套接字协议，如果协议族是PF_INET且协议是0或者负数，它会默认为IPPROTO_TCP 
kCFSocketConnectCallBack, // 触发回调函数的socket消息类型，具体见Callback Types 
TCPServerConnectCallBack, // 上面情况下触发的回调函数 
&sockContext // 一个持有CFSocket结构信息的对象，可以为nil 
); 
 
if (_socket != nil) { 
    struct sockaddr_in addr4;   // IPV4 
    memset(&addr4, 0, sizeof(addr4)); 
    addr4.sin_len = sizeof(addr4); 
    addr4.sin_family = AF_INET; 
    addr4.sin_port = htons(8888); 
    addr4.sin_addr.s_addr = inet_addr([strAddress UTF8String]);  // 把字符串的地址转换为机器可识别的网络地址 
        
    // 把sockaddr_in结构体中的地址转换为Data 
    CFDataRef address = CFDataCreate(kCFAllocatorDefault, (UInt8 *)&addr4, sizeof(addr4)); 
    CFSocketConnectToAddress(_socket, // 连接的socket 
address, // CFDataRef类型的包含上面socket的远程地址的对象 
-1  // 连接超时时间，如果为负，则不尝试连接，而是把连接放在后台进行，如果_socket消息类型为kCFSocketConnectCallBack，将会在连接成功或失败的时候在后台触发回调函数 
); 
 
    CFRunLoopRef cRunRef = CFRunLoopGetCurrent();    // 获取当前线程的循环 
    // 创建一个循环，但并没有真正加如到循环中，需要调用CFRunLoopAddSource 
    CFRunLoopSourceRef sourceRef = CFSocketCreateRunLoopSource(kCFAllocatorDefault, _socket, 0); 
    CFRunLoopAddSource(cRunRef, // 运行循环 
    sourceRef,  // 增加的运行循环源, 它会被retain一次 
    kCFRunLoopCommonModes  // 增加的运行循环源的模式 
    ); 
    CFRelease(courceRef); 
} 
 
2. 设置回调函数 
// socket回调函数的格式： 
static void TCPServerConnectCallBack(CFSocketRef socket, CFSocketCallBackType type, CFDataRef address, const void *data, void *info) ｛ 
    if (data != NULL) { 
        // 当socket为kCFSocketConnectCallBack时，失败时回调失败会返回一个错误代码指针，其他情况返回NULL 
        NSLog(@"连接失败"); 
        return; 
    } 
    TCPClient *client = (TCPClient *)info; 
    // 读取接收的数据 
    [info performSlectorInBackground:@selector(readStream) withObject:nil]; 
｝ 
 
3. 接收发送数据 
// 读取接收的数据 
- (void)readStream { 
    char buffer[1024]; 
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; 
    while (recv(CFSocketGetNative(_socket), //与本机关联的Socket 如果已经失效返回－1:INVALID_SOCKET 
           buffer, sizeof(buffer), 0)) { 
        NSLog(@"%@", [NSString stringWithUTF8String:buffer]); 
    } 
} 
 
// 发送数据 
- (void)sendMessage { 
    NSString *stringTosend = @"你好"; 
    char *data = [stringTosend UTF8String]; 
    send(SFSocketGetNative(_socket), data, strlen(data) + 1, 0); 
} 
 
 
服务器端： 
 
CFSockteRef _socket; 
CFWriteStreamRef outputStream = NULL; 
 
int setupSocket() { 
    _socket = CFSocketCreate(kCFAllocatorDefault, PF_INET, SOCK_STREAM, IPPROTO_TCP, kCFSocketAcceptCallBack, TCPServerAcceptCallBack, NULL); 
    if (NULL == _socket) { 
        NSLog(@"Cannot create socket!"); 
        return 0; 
    } 
    
    int optval = 1; 
    setsockopt(CFSocketGetNative(_socket), SOL_SOCKET, SO_REUSEADDR, // 允许重用本地地址和端口 
(void *)&optval, sizeof(optval)); 
    
    struct sockaddr_in addr4; 
    memset(&addr4, 0, sizeof(addr4)); 
    addr4.sin_len = sizeof(addr4); 
    addr4.sin_family = AF_INET; 
    addr4.sin_port = htons(port); 
    addr4.sin_addr.s_addr = htonl(INADDR_ANY); 
    CFDataRef address = CFDataCreate(kCFAllocatorDefault, (UInt8 *)&addr4, sizeof(addr4)); 
    
    if (kCFSocketSuccess != CFSocketSetAddress(_socket, address)) { 
        NSLog(@"Bind to address failed!"); 
        if (_socket) 
             CFRelease(_socket); 
        _socket = NULL; 
        return 0; 
    } 
        
    CFRunLoopRef cfRunLoop = CFRunLoopGetCurrent(); 
    CFRunLoopSourceRef source = CFSocketCreateRunLoopSource(kCFAllocatorDefault, _socket, 0); 
    CFRunLoopAddSource(cfRunLoop, source, kCFRunLoopCommonModes); 
    CFRelease(source); 
    
    return 1; 
} 
 
// socket回调函数，同客户端 
void TCPServerAcceptCallBack(CFSocketRef socket, CFSocketCallBackType type, CFDataRef address, const void *data, void *info) { 
    if (kCFSocketAcceptCallBack == type) { 
        // 本地套接字句柄 
        CFSocketNativeHandle nativeSocketHandle = *(CFSocketNativeHandle *)data; 
        uint8_t name[SOCK_MAXADDRLEN];       
        socklen_t nameLen = sizeof(name); 
        if (0 != getpeername(nativeSocketHandle, (struct sockaddr *)name, &nameLen)) { 
            NSLog(@"error"); 
            exit(1); 
        } 
        NSLog(@"%@ connected.", inet_ntoa( ((struct sockaddr_in *)name)->sin_addr )): 
 
        CFReadStreamRef iStream; 
        CFWriteStreamRef oStream; 
        // 创建一个可读写的socket连接 
        CFStreamCreatePairWithSocket(kCFAllocatorDefault, nativeSocketHandle, &iStream, &oStream);  
        if (iStream && oStream) { 
            CFStreamClientContext streamContext = {0, NULL, NULL, NULL}; 
            if (!CFReadStreamSetClient(iStream, kCFStreamEventHasBytesAvaiable, 
                                       readStream, // 回调函数，当有可读的数据时调用 
                                       &streamContext)){ 
                exit(1); 
            } 
 
            if (!CFReadStreamSetClient(iStream, kCFStreamEventCanAcceptBytes, writeStream, &streamContext)){ 
                exit(1); 
            } 
 
            CFReadStreamScheduleWithRunLoop(iStream, CFRunLoopGetCurrent(), kCFRunLoopCommomModes); 
            CFWriteStreamScheduleWithRunLoop(wStream, CFRunLoopGetCurrent(), kCFRunLoopCommomModes); 
            CFReadStreamOpen(iStream); 
            CFWriteStreamOpen(wStream); 
        } else { 
             close(nativeSocketHandle);  
        } 
    } 
} 
 
// 读取数据 
void readStream(CFReadStreamRef stream, CFStreamEventType eventType, void *clientCallBackInfo) { 
    UInt8 buff[255]; 
    CFReadStreamRead(stream, buff, 255); 
    printf("received: %s", buff); 
} 
 
void writeStream (CFWriteStreamRef stream, CFStreamEventType eventType, void *clientCallBackInfo) { 
    outputStream = stream; 
} 
 
main { 
    char *str = "nihao"; 
    
    if (outputStream != NULL) { 
        CFWriteStreamWrite(outputStream, str, strlen(line) + 1); 
    } else { 
        NSLog(@"Cannot send data!"); 
    } 
} 
 
// 开辟一个线程线程函数中 
void runLoopInThread() { 
    int res = setupSocket(); 
    if (!res) { 
        exit(1); 
    } 
    CFRunLoopRun();    // 运行当前线程的CFRunLoop对象 
}