iOS

1、CFSocket

• 苹果对对底层 BSD Socket 进行轻量级的封装（纯 C）。

• 主要使用的 API：CFSocekt 用于建立连接，CFStream 用于读写数据。

2、基本使用

2.1 Client 客户端

• TCP 客户端

  	// 包含头文件
  	#import <sys/socket.h>
  	#import <netinet/in.h>
  	#import <arpa/inet.h>
  	
  	@property (weak, nonatomic) IBOutlet UITextField *desIPTF;
  	@property (weak, nonatomic) IBOutlet UITextField *desPortTF;
  	
  	@property (weak, nonatomic) IBOutlet UITextView *recvTextView;
  	@property (weak, nonatomic) IBOutlet UITextField *sendTF;
  	
  	@property (nonatomic, assign) CFSocketRef clientSockfd;
  
  	#pragma mark - 创建 TCP 连接
  	
  	- (IBAction)connectTCPServer:(id)sender {
  	    
  	    [NSThread detachNewThreadSelector:@selector(connectTCPSer) toTarget:self withObject:nil];
  	}
  	
  	- (void)connectTCPSer {
  	    
  	    BOOL success;
  	    
  	    // 创建 socket
  	    self.clientSockfd = CFSocketCreate(kCFAllocatorDefault, PF_INET, SOCK_STREAM, IPPROTO_TCP, kCFSocketConnectCallBack, ServerConnectCallBack, NULL);
  	    success = (self.clientSockfd != nil);
  	    
  	    NSString *logStr = nil;
  	    
  	    if (success == NO) {
  	        
  	        logStr = @"创建 socket 失败...
  ";
  	        [self showMessage:logStr];
  	        
  	        return;
  	        
  	    } else {
  	        
  	        logStr = @"创建 socket 成功...
  ";
  	        [self showMessage:logStr];
  	        
  	        // 服务器地址
  	        struct sockaddr_in ser_addr;
  	        memset(&ser_addr, 0, sizeof(ser_addr));
  	        ser_addr.sin_len         = sizeof(ser_addr);
  	        ser_addr.sin_family      = AF_INET;
  	        ser_addr.sin_port        = htons(_desPortTF.text.intValue);
  	        ser_addr.sin_addr.s_addr = inet_addr(_desIPTF.text.UTF8String);
  	        
  	        CFDataRef address = CFDataCreate(kCFAllocatorDefault, (UInt8 *)&ser_addr, sizeof((ser_addr)));
  	        
  	        // 连接
  	        CFSocketError result = CFSocketConnectToAddress(self.clientSockfd, address, 5);
  	        CFRelease(address);
  	        success = (result == kCFSocketSuccess);
  	    }
  	    
  	    if (success == NO) {
  	        
  	        logStr = @"socket 连接失败...
  ";
  	        [self showMessage:logStr];
  	        
  	        return;
  	        
  	    } else {
  	        
  	        logStr = [NSString stringWithFormat:@"socket 连接 %@ 成功...
  ", _desIPTF.text];
  	        [self showMessage:logStr];
  	        
  	        char buf[2048];
  	        do {
  	            // 接收数据
  	            ssize_t recvLen = recv(CFSocketGetNative(self.clientSockfd), buf, sizeof(buf), 0);
  	            
  	            if (recvLen > 0) {
  	                logStr = [NSString stringWithFormat:@"recv：%@
  ", [NSString stringWithFormat:@"%s", buf]];
  	                [self showMessage:logStr];
  	            }
  	            
  	        } while (strcmp(buf, "exit") != 0);
  	        
  	        CFRunLoopRef cfrl = CFRunLoopGetCurrent();
  	        CFRunLoopSourceRef source = CFSocketCreateRunLoopSource(kCFAllocatorDefault, self.clientSockfd, 0);
  	        CFRunLoopAddSource(cfrl, source, kCFRunLoopCommonModes);
  	        CFRelease(source);
  	        CFRunLoopRun();
  	    }
  	}
  	
  	// 连接成功的回调函数
  	void ServerConnectCallBack(CFSocketRef socket, CFSocketCallBackType type, CFDataRef address, const void * data, void *info) {
  	    
  	    if (data != NULL) {
  	        NSLog(@"connect
  ");
  	    } else {
  	        NSLog(@"connect success
  ");
  	    }
  	}
  	
  	#pragma mark - 发送数据
  	
  	- (IBAction)btnClick:(id)sender {
  	    
  	    if (_sendTF.text.length == 0) {
  	        return;
  	    } else {
  	        
  	        // 发送数据
  	        ssize_t sendLen = send(CFSocketGetNative(self.clientSockfd), _sendTF.text.UTF8String, strlen(_sendTF.text.UTF8String), 0);
  	
  	        if (sendLen > 0) {
  	            NSString *logStr = [NSString stringWithFormat:@"send：%@
  ", _sendTF.text];
  	            [self showMessage:logStr];
  	        }
  	    }
  	}
  	
  	// 显示信息
  	- (void)showMessage:(NSString *)msg {
  	    
  	    dispatch_async(dispatch_get_main_queue(), ^{
  	        
  	        _recvTextView.text = [_recvTextView.text stringByAppendingString:msg];
  	    });
  	}
  	
  	// 键盘回收
  	- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
  	    [self.view endEditing:YES];
  	}
  

  

2.2 Server 服务端

• TCP 服务端

  	// 包含头文件
  	#import <sys/socket.h>
  	#import <netinet/in.h>
  	#import <arpa/inet.h>
  	#import <ifaddrs.h>
  	
  	static ViewController *selfClass = nil;
  	
  	@property (weak, nonatomic) IBOutlet UITextField *locIPTF;
  	@property (weak, nonatomic) IBOutlet UITextField *locPortTF;
  	
  	@property (weak, nonatomic) IBOutlet UITextView *recvTextView;
  	@property (weak, nonatomic) IBOutlet UITextField *sendTF;
  	
  	@property (nonatomic, assign) CFSocketRef serverSockfd;
  	
  	@property (nonatomic, assign) CFWriteStreamRef outputStream;
  
  	- (void)viewDidLoad {
  	    [super viewDidLoad];
  	    
  	    NSString *ip_addr = [self getIPAddress];
  	    _locIPTF.text = ip_addr;
  	    
  	    // 函数指针指向本身
  	    selfClass = self;
  	}
  	
  	#pragma mark - 创建 TCP 监听
  	
  	- (IBAction)createdTCPServer:(id)sender {
  	    
  	    [sender setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
  	    
  	    [NSThread detachNewThreadSelector:@selector(createdTCPSer) toTarget:self withObject:nil];
  	}
  	
  	- (void)createdTCPSer {
  	    
  	    BOOL success;
  	    
  	    // 创建 socket
  	    self.serverSockfd = CFSocketCreate(kCFAllocatorDefault, PF_INET, SOCK_STREAM, IPPROTO_TCP, kCFSocketAcceptCallBack, TCPServerAcceptCallBack, NULL);
  	    success = (self.serverSockfd != NULL);
  	    
  	    NSString *logStr = nil;
  	    
  	    if (success == NO) {
  	        
  	        logStr = @"创建 socket 失败...
  ";
  	        [self showMessage:logStr];
  	        
  	        return;
  	        
  	    } else {
  	        
  	        logStr = @"创建 socket 成功...
  ";
  	        [self showMessage:logStr];
  	        
  	        int optVal = 1;
  	        setsockopt(CFSocketGetNative(self.serverSockfd), SOL_SOCKET, SO_REUSEADDR, (void*)&optVal,sizeof(optVal));
  	        
  	        // 本地地址
  	        struct sockaddr_in loc_addr;
  	        memset(&loc_addr, 0, sizeof(loc_addr));
  	        loc_addr.sin_family      = AF_INET;
  	        loc_addr.sin_port        = htons(_locPortTF.text.intValue);
  	        loc_addr.sin_addr.s_addr = inet_addr(_locIPTF.text.UTF8String);
  	        
  	        CFDataRef address = CFDataCreate(kCFAllocatorDefault, (UInt8*)&loc_addr, sizeof(loc_addr));
  	        
  	        // 绑定
  	        CFSocketError err = CFSocketSetAddress(self.serverSockfd, address);
  	        CFRelease(address);
  	        success = (err == kCFSocketSuccess);
  	    }
  	    
  	    if (success == NO) {
  	        
  	        logStr = @"socket 绑定失败...
  ";
  	        [self showMessage:logStr];
  	        
  	        CFRelease(self.serverSockfd);
  	        self.serverSockfd = NULL;
  	        
  	        return;
  	        
  	    } else {
  	        
  	        logStr = @"socket 绑定成功...
  ";
  	        [self showMessage:logStr];
  	        
  	        CFRunLoopRef cfRunloop = CFRunLoopGetCurrent();
  	        CFRunLoopSourceRef source = CFSocketCreateRunLoopSource(kCFAllocatorDefault, self.serverSockfd, 0);
  	        CFRunLoopAddSource(cfRunloop, source, kCFRunLoopCommonModes);
  	        CFRelease(source);
  	        CFRunLoopRun();
  	    }
  	}
  	
  	// 客户端连接成功的回调函数
  	void TCPServerAcceptCallBack(CFSocketRef socket ,CFSocketCallBackType type,CFDataRef address,const void *data, void *info) {
  	    
  	    // 客户端连接
  	    if (kCFSocketAcceptCallBack == type) {
  	        
  	        // data  the handle of socket
  	        CFSocketNativeHandle nativeSocketHandle = *(CFSocketNativeHandle *)data;
  	        
  	        uint8_t name[SOCK_MAXADDRLEN];
  	        socklen_t nameLen = sizeof(name);
  	        
  	        // 获取对方 socket 信息，还有 getsocketname() 函数用于获取本程序所在 socket 信息
  	        if (getpeername(nativeSocketHandle, (struct sockaddr *)name, &nameLen) != 0) {
  	            exit(1);
  	        }
  	        
  	        // 获取连接的客户端信息
  	        struct sockaddr_in * addr_in = (struct sockaddr_in *)name;
  	        char *ip_addr = inet_ntoa(addr_in->sin_addr);
  	        int ip_port   = addr_in->sin_port;
  	        
  	        NSString *logStr = [NSString stringWithFormat:@"已连接：%s，port：%d
  ", ip_addr, ip_port];
  	        [selfClass showMessage:logStr];
  	        
  	        // 创建一对输入输出流用于读写数据
  	        CFReadStreamRef iStream;
  	        CFWriteStreamRef oStream;
  	        
  	        // 创建一组可读/写的 CFStreame
  	        CFStreamCreatePairWithSocket(kCFAllocatorDefault, nativeSocketHandle, &iStream, &oStream);
  	        
  	        if (iStream && oStream) {
  	            
  	            // 打开输入流和输出流
  	            CFReadStreamOpen(iStream);
  	            CFWriteStreamOpen(oStream);
  	            
  	            CFStreamClientContext streamContext = {0, NULL, NULL, NULL};
  	            
  	            // if have data to read   call the readStream function
  	            if (!CFReadStreamSetClient(iStream, kCFStreamEventHasBytesAvailable, readStream, &streamContext)) {
  	                exit(1);
  	            }
  	            
  	            CFReadStreamScheduleWithRunLoop(iStream, CFRunLoopGetCurrent(), kCFRunLoopCommonModes);
  	            
  	            selfClass.outputStream = oStream;
  	        }
  	    }
  	}
  	
  	// 读取数据的回调函数
  	void readStream(CFReadStreamRef iStream, CFStreamEventType eventType, void * clientCallBackInfo){
  	    
  	    char buf[2048];
  	    bzero(buf, sizeof(buf));
  	    
  	    do {
  	        // 接收数据
  	        CFIndex dex = CFReadStreamRead(iStream, (UInt8 *)buf, sizeof(buf));
  	        
  	        if (dex > 0) {
  	            NSString *logStr = [NSString stringWithFormat:@"recv：%@
  ", [NSString stringWithFormat:@"%s", buf]];
  	            [selfClass showMessage:logStr];
  	        }
  	        
  	    } while (strcmp(buf, "exit") != 0);
  	}
  	
  	#pragma mark - 发送数据
  	
  	- (IBAction)btnClick:(id)sender {
  	    
  	    if (_sendTF.text.length == 0) {
  	        return;
  	    } else {
  	        
  	        // 发送数据
  	        CFIndex dex = CFWriteStreamWrite(selfClass.outputStream, (UInt8 *)_sendTF.text.UTF8String, strlen(_sendTF.text.UTF8String)+1);
  	        
  	        if (dex > 0) {
  	            NSString *logStr = [NSString stringWithFormat:@"send：%@
  ", _sendTF.text];
  	            [self showMessage:logStr];
  	        }
  	    }
  	}
  	
  	#pragma mark - 获取本地 IP 地址
  	
  	- (NSString *)getIPAddress {
  	    
  	    NSString *address = @"error";
  	    struct ifaddrs *interfaces = NULL;
  	    struct ifaddrs *temp_addr = NULL;
  	    int success = 0;
  	    
  	    // retrieve the current interfaces - returns 0 on success
  	    success = getifaddrs(&interfaces);
  	    
  	    if (success == 0) {
  	        
  	        // Loop through linked list of interfaces
  	        temp_addr = interfaces;
  	        
  	        while (temp_addr != NULL) {
  	            
  	            if (temp_addr->ifa_addr->sa_family == AF_INET) {
  	                
  	                // Check if interface is en0 which is the wifi connection on the iPhone
  	                if ([[NSString stringWithUTF8String:temp_addr->ifa_name] isEqualToString:@"en0"]) {
  	                    
  	                    // Get NSString from C String
  	                    address = [NSString stringWithUTF8String:inet_ntoa(((struct sockaddr_in *)temp_addr->ifa_addr)->sin_addr)];
  	                }
  	            }
  	            temp_addr = temp_addr->ifa_next;
  	        }
  	    }
  	    
  	    // Free memory
  	    freeifaddrs(interfaces);
  	    return address;
  	}
  	
  	// 显示信息
  	- (void)showMessage:(NSString *)msg {
  	    
  	    dispatch_async(dispatch_get_main_queue(), ^{
  	        
  	        _recvTextView.text = [_recvTextView.text stringByAppendingString:msg];
  	    });
  	}
  	
  	// 键盘回收
  	- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
  	    [self.view endEditing:YES];
  	}