ubuntu下udp源码

在Ubuntu下，我们可以使用C语言编写UDP的源代码。下面是一个简单的UDP客户端和服务器的示例：

UDP服务器端代码：

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

#define PORT 8888
#define BUF_SIZE 1024

int main()
{
    int sockfd;
    struct sockaddr_in server_addr, client_addr;
    char buffer[BUF_SIZE];

    // 创建socket
    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
        perror("socket error");
        exit(1);
    }

    // 设置服务器地址
    bzero(&server_addr, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(PORT);
    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);

    // 绑定socket到地址和端口
    if (bind(sockfd, (struct sockaddr*)&server_addr, sizeof(server_addr)) == -1) {
        perror("bind error");
        exit(1);
    }

    printf("UDP server listening on port %d...\n", PORT);

    while (1) {
        socklen_t addr_len = sizeof(struct sockaddr_in);

        // 接收消息
        int received_bytes = recvfrom(sockfd, buffer, BUF_SIZE, 0, (struct sockaddr*)&client_addr, &addr_len);
        buffer[received_bytes] = '\0';
        printf("Received message from client: %s\n", buffer);

        // 发送响应
        char response[] = "Hello from server!";
        sendto(sockfd, response, strlen(response), 0, (struct sockaddr*)&client_addr, addr_len);
    }

    close(sockfd);

    return 0;
}

UDP客户端代码：

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

#define SERVER_IP "127.0.0.1"
#define PORT 8888
#define BUF_SIZE 1024

int main()
{
    int sockfd;
    struct sockaddr_in server_addr;
    char buffer[BUF_SIZE];

    // 创建socket
    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
        perror("socket error");
        exit(1);
    }

    // 设置服务器地址
    bzero(&server_addr, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(PORT);
    server_addr.sin_addr.s_addr = inet_addr(SERVER_IP);

    while (1) {
        // 输入消息
        printf("Enter message: ");
        fgets(buffer, BUF_SIZE, stdin);
        buffer[strlen(buffer) - 1] = '\0';

        // 发送消息
        sendto(sockfd, buffer, strlen(buffer), 0, (struct sockaddr*)&server_addr, sizeof(server_addr));

        // 接收响应
        socklen_t addr_len = sizeof(struct sockaddr_in);
        int received_bytes = recvfrom(sockfd, buffer, BUF_SIZE, 0, (struct sockaddr*)&server_addr, &addr_len);
        buffer[received_bytes] = '\0';
        printf("Received response from server: %s\n", buffer);
    }

    close(sockfd);

    return 0;
}

可以在Ubuntu上使用gcc编译器编译上述代码：

gcc server.c -o server
gcc client.c -o client

然后分别运行服务器和客户端：

./server
./client

服务器将监听8888端口并等待客户端发送消息，客户端将接收用户输入的消息并发送至服务器，服务器接收到消息后发送响应到客户端，并将响应打印出来。