c - C Socket 代码在 LAN 内工作，但不能在 WAN 上工作？拒绝连接？

Question

我一直在开发一个连接 4 游戏，该游戏在 TCP 连接的主要功能中包含客户端和服务器代码。我无法通过互联网连接。我尝试在不在 LAN 上的笔记本电脑上运行客户端代码，指定 LAN 的公共 IP 和所需的端口号。但是，当连接失败时，继续拒绝连接作为我的错误消息。

//客户端代码

if(argc == 3){
        turn = CLIENT;
        int status, client_sockfd;
        struct addrinfo hints, *res;
    
        memset(&hints, 0, sizeof(hints));
        hints.ai_family = AF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;

        if((status = getaddrinfo(argv[1], argv[2], &hints, &res)) != 0){
            fprintf(stderr, "getaddrinfo error: %s\n", gai_strerror(status));       
            exit(1);
        }   

        if((client_sockfd = socket(res -> ai_family, res -> ai_socktype, res -> ai_protocol)) == -1){
            fprintf(stderr, "socket creation error: %s\n", gai_strerror(client_sockfd));        
            exit(1);
        }

        
        if((connect(client_sockfd, res -> ai_addr, res -> ai_addrlen)) == -1){
            perror("cannot connect");       
            exit(1);
        }
        
            freeaddrinfo(res); //free res structure 

            //Start of Game: Client 
            recv(client_sockfd, player1, 25, 0);
            printf("Player 2, enter your name:\n");
            fgets(player2, sizeof(player2), stdin);
            send(client_sockfd, player2, 25, 0); 
            sock = client_sockfd;

        }

//服务器网络代码

else{
         turn = SERVER;
         int server_sockfd;
         printf("Setting up the game\n");

        //server port 
        if(argc == 2)
            myport = argv[1];
        else
            myport = "12345";
        
        int status, sock_fd;
        int opt = 1;
        struct addrinfo  hints, *res;
        struct sockaddr_storage their_addr;
        socklen_t addr_size;
        memset(&hints, 0, sizeof(hints)); //make sure hints is empty
        hints.ai_family = AF_UNSPEC; //ipv6 or ipv4 doesn't matter
        hints.ai_socktype = SOCK_STREAM; //require TCP stream sockets
        hints.ai_flags = AI_PASSIVE;
        
        //load res adderinfo struct 
        if((status = getaddrinfo(NULL, myport, &hints, &res)) != 0){
            fprintf(stderr, "getaddrinfo error: %s\n", gai_strerror(status));       
            exit(1);
            }
        
        
        //create socket with res
        if((sock_fd = socket(res -> ai_family, res -> ai_socktype, res -> ai_protocol)) == -1){
            fprintf(stderr, "socket creation error: %s\n", gai_strerror(sock_fd));      
            exit(1);
            }

        //reuseable socket
        if(setsockopt(sock_fd,SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) == -1){
            perror("setsockopt");
            exit(1);
            }
        //bind socket for use 
        if((bind(sock_fd, res -> ai_addr, res-> ai_addrlen)) == -1){
            perror("binding fail");
            exit(1);
            }
        
        
        //listen with a backlog of 5 
        listen(sock_fd, 5);

        addr_size = sizeof(their_addr);
        if((server_sockfd = accept(sock_fd, (struct sockaddr *)&their_addr, &addr_size)) == -1){
            perror("accepting failure");
            exit(1);
            }

        freeaddrinfo(res); //free res structure 
        
        //Start of Game: Server 
        printf("Player 1, please enter your name:\n");  
        fgets(player1, sizeof(player1), stdin);
        send(server_sockfd, player1, 25, 0); 
        recv(server_sockfd, player2, 25, 0);
        sock = server_sockfd;   
    }

有什么想法吗？据我了解，作为客户端，我的数据包应该到达服务器的网关，而 NAT 应该使用我的目标端口将我的消息重定向到服务器？

标签： csocketsdnsposixnat