[How to implement wifi communication in C language]

How to implement wifi communication

In C language, you can use socket (socket) library function to realize WiFi communication. The following is a simple C language code example using socket functions to implement WiFi communication, which is used to connect to the target WiFi network and send data:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <errno.h>

#define PORT "8080" // 目标WiFi网络的端口号

int main(int argc, char **argv) {
    
    
    int sockfd, status;
    struct addrinfo hints, *res;
    char *hostname = "www.example.com"; // 目标WiFi网络的主机名
    char *message = "Hello, WiFi!"; // 要发送的数据
    int bytes_sent;

    memset(&hints, 0, sizeof hints);
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;

    // 解析目标WiFi网络的地址信息
    if ((status = getaddrinfo(hostname, PORT, &hints, &res)) != 0) {
    
    
        fprintf(stderr, "getaddrinfo error: %s\n", gai_strerror(status));
        return 1;
    }

    // 创建套接字连接
    sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);

    // 连接到目标WiFi网络
    if (connect(sockfd, res->ai_addr, res->ai_addrlen) == -1) {
    
    
        perror("connect");
        return 1;
    }

    // 发送数据到目标WiFi网络
    bytes_sent = send(sockfd, message, strlen(message), 0);

    // 关闭套接字连接
    close(sockfd);
    return 0;
}

The above code uses the socket library function to connect to the target WiFi network and send data. The specific implementation method can be adjusted as required. It should be noted that you need to provide the correct host name and port number of the WiFi network in order to connect to the target WiFi network.

What is a socket

A socket is an API for communicating in a computer network, which provides a standard way of exchanging data between different hosts. A socket API typically includes a set of system calls, functions, and data structures that can be used to create, bind, listen, connect, send, and receive data over a network.

In network communication, sockets provide a connection-oriented communication method, that is, communication is realized by establishing a connection. When using sockets for communication, the communicating parties need to use a protocol to define the data format and transmission method. Common protocols include TCP/IP, UDP, HTTP, FTP, etc.

Sockets can be used in various types of network applications such as web servers, email clients, file transfer protocols, etc. The use of sockets can be implemented through the standard library of the programming language or a third-party library. In C language, you can use socket library functions for network programming.

Socket security

The socket itself does not provide security guarantees, because it is only a communication API, it does not care about the content of the data or security issues. The service provided by the socket is the underlying and basic communication function, and the security issues such as data confidentiality, integrity and reliability need to be realized by other means.

In practical applications, we usually use some security protocols to ensure the security of communication, such as TLS/SSL protocol. The TLS/SSL protocol can provide a layer of security between the application layer and the transport layer. It can encrypt and verify communication data, protect the privacy and integrity of data, and at the same time verify the identities of both parties in communication to ensure the reliability of communication. .

When using sockets for network programming, we should pay attention to security issues and take some measures to protect the security of data. For example, we can use the TLS/SSL protocol to encrypt communication data, or use some encryption algorithms to encrypt data. In addition, we should also pay attention to avoid some common security holes, such as buffer overflow, denial of service attacks, etc., in order to improve the security of network communication.