linux udp如何传输数据图解

+-------------------+        +-------------------+        +-------------------+
|   发送方应用      | -----> |   发送方UDP套接字 | -----> |   网络传输层      |
+-------------------+        +-------------------+        +-------------------+
                                                                  |
                                                                  v
+-------------------+        +-------------------+        +-------------------+
|   接收方UDP套接字 | <----- |   网络传输层      | <----- |   接收方应用      |
+-------------------+        +-------------------+        +-------------------+

// 示例代码：发送端
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define PORT 8080
#define BUFFER_SIZE 1024

int main() {
    int sockfd;
    struct sockaddr_in servaddr, cliaddr;
    char buffer[BUFFER_SIZE];

    // 创建UDP套接字
    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("socket creation failed");
        exit(EXIT_FAILURE);
    }

    memset(&servaddr, 0, sizeof(servaddr));
    memset(&cliaddr, 0, sizeof(cliaddr));

    // 填充服务器信息
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = INADDR_ANY;
    servaddr.sin_port = htons(PORT);

    // 绑定套接字
    if (bind(sockfd, (const struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) {
        perror("bind failed");
        exit(EXIT_FAILURE);
    }

    // 发送数据
    sendto(sockfd, (const char *)buffer, strlen(buffer), MSG_CONFIRM, (const struct sockaddr *)&cliaddr, sizeof(cliaddr));
    printf("Message sent.\n");

    close(sockfd);
    return 0;
}

// 示例代码：接收端
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define PORT 8080
#define BUFFER_SIZE 1024

int main() {
    int sockfd;
    struct sockaddr_in servaddr, cliaddr;
    socklen_t len;
    char buffer[BUFFER_SIZE];

    // 创建UDP套接字
    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("socket creation failed");
        exit(EXIT_FAILURE);
    }

    memset(&servaddr, 0, sizeof(servaddr));
    memset(&cliaddr, 0, sizeof(cliaddr));

    // 填充服务器信息
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = INADDR_ANY;
    servaddr.sin_port = htons(PORT);

    // 绑定套接字
    if (bind(sockfd, (const struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) {
        perror("bind failed");
        exit(EXIT_FAILURE);
    }

    len = sizeof(cliaddr);

    // 接收数据
    recvfrom(sockfd, (char *)buffer, BUFFER_SIZE, 0, (struct sockaddr *)&cliaddr, &len);
    printf("Received message: %s\n", buffer);

    close(sockfd);
    return 0;
}