ios oc socket组播包发送与接收

1. 发送组播包

在 iOS 中，可以使用 MulticastSocket 来发送组播包。以下是发送组播包的步骤：

1）创建 MulticastSocket 对象：

self.multicastSocket = [[GCDAsyncUdpSocket alloc] initWithDelegate:self delegateQueue:dispatch_get_main_queue()];

2）设置 MulticastSocket 的发送地址和端口：

NSString *host = @"224.0.0.1";
int port = 12345;
NSError *error = nil;
[self.multicastSocket enableBroadcast:YES error:&error];
[self.multicastSocket joinMulticastGroup:host error:&error];
[self.multicastSocket beginReceiving:&error];

3）发送组播包：

NSString *message = @"Hello, world!";
NSData *data = [message dataUsingEncoding:NSUTF8StringEncoding];
[self.multicastSocket sendData:data toHost:host port:port withTimeout:-1 tag:0];

2. 接收组播包

以下是接收组播包的步骤：

1）创建 MulticastSocket 对象：

self.multicastSocket = [[GCDAsyncUdpSocket alloc] initWithDelegate:self delegateQueue:dispatch_get_main_queue()];

2）设置 MulticastSocket 的接收地址和端口：

NSString *host = @"224.0.0.1";
int port = 12345;
NSError *error = nil;
[self.multicastSocket enableBroadcast:YES error:&error];
[self.multicastSocket joinMulticastGroup:host error:&error];
[self.multicastSocket beginReceiving:&error];

3）实现 GCDAsyncUdpSocketDelegate 的回调方法：

- (void)udpSocket:(GCDAsyncUdpSocket *)sock didReceiveData:(NSData *)data fromAddress:(NSData *)address withFilterContext:(nullable id)filterContext {
    NSString *message = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    NSLog(@"Received message: %@", message);
}

这样就可以接收到发送到指定组播地址和端口的包了。