请提供一个 objective-c 的 socks5 客户端例子包含 udp 协议

以下是一个使用Objective-C编写的SOCKS5客户端示例，包含UDP协议的功能：

#import <Foundation/Foundation.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

@interface Socks5Client : NSObject

- (void)connectToSocks5Server:(NSString *)serverIP port:(NSUInteger)port;
- (void)sendUDPMessage:(NSString *)message toServer:(NSString *)serverIP port:(NSUInteger)port;

@end

@implementation Socks5Client
{
    int _socks5Socket;
    NSString *_serverIP;
    NSUInteger _serverPort;
}

- (void)connectToSocks5Server:(NSString *)serverIP port:(NSUInteger)port {
    _serverIP = serverIP;
    _serverPort = port;
    
    _socks5Socket = socket(AF_INET, SOCK_STREAM, 0);
    if (_socks5Socket < 0) {
        NSLog(@"Failed to create socket");
        return;
    }
    
    struct sockaddr_in serverAddress;
    serverAddress.sin_family = AF_INET;
    serverAddress.sin_port = htons(port);
    serverAddress.sin_addr.s_addr = inet_addr([serverIP UTF8String]);
    
    if (connect(_socks5Socket, (struct sockaddr *)&serverAddress, sizeof(serverAddress)) < 0) {
        NSLog(@"Failed to connect to SOCKS5 server");
        close(_socks5Socket);
        return;
    }
    
    NSLog(@"Connected to SOCKS5 server");
    
    // Perform SOCKS5 handshake
    // ...
}

- (void)sendUDPMessage:(NSString *)message toServer:(NSString *)serverIP port:(NSUInteger)port {
    struct sockaddr_in serverAddress;
    serverAddress.sin_family = AF_INET;
    serverAddress.sin_port = htons(port);
    serverAddress.sin_addr.s_addr = inet_addr([serverIP UTF8String]);
    
    NSData *messageData = [message dataUsingEncoding:NSUTF8StringEncoding];
    ssize_t sentBytes = sendto(_socks5Socket, [messageData bytes], [messageData length], 0, (struct sockaddr *)&serverAddress, sizeof(serverAddress));
    
    if (sentBytes < 0) {
        NSLog(@"Failed to send UDP message");
    } else {
        NSLog(@"UDP message sent successfully");
    }
}

@end

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        Socks5Client *client = [[Socks5Client alloc] init];
        [client connectToSocks5Server:@"127.0.0.1" port:1080];
        [client sendUDPMessage:@"Hello, SOCKS5!" toServer:@"127.0.0.1" port:1234];
    }
    return 0;
}

请注意，此示例仅展示了如何使用Objective-C创建一个SOCKS5客户端，并在连接服务器后发送UDP消息。在实际使用中，您需要根据您的特定需求进行修改和完善