linux udp发包程序

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

int main(int argc, char *argv[]) {
    if (argc != 4) {
        fprintf(stderr, "Usage: %s<ip> <port> <message>\n", argv[0]);
        return 1;
    }

    const char *ip = argv[1];
    int port = atoi(argv[2]);
    const char *message = argv[3];

    int sockfd;
    struct sockaddr_in servaddr;

    // 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));

    // Filling server information
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(port);
    servaddr.sin_addr.s_addr = inet_addr(ip);

    // 发送数据报文
    sendto(sockfd, message, strlen(message), 0, (const struct sockaddr *)&servaddr, sizeof(servaddr));
    printf("Message sent to %s:%d\n", ip, port);

    close(sockfd);
    return 0;
}

gcc udp_send.c -o udp_send
./udp_send 127.0.0.1 8888 "Hello, UDP Server!"