test_client.c

#include <netinet/in.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>

#define SERVER_PORT 8888
#define BUFF_LEN 512
#define SERVER_IP "172.0.5.182"

void udp_msg_sender(int fd, struct sockaddr* dst) {}

/*
    client:
            socket-->sendto-->revcfrom-->close
*/

int main(int argc, char* argv[]) {
  int                client_fd;
  struct sockaddr_in ser_addr;

  client_fd = socket(AF_INET, SOCK_DGRAM, 0);
  if (client_fd < 0) {
    printf("create socket fail!\n");
    return -1;
  }

  memset(&ser_addr, 0, sizeof(ser_addr));
  ser_addr.sin_family = AF_INET;
  // ser_addr.sin_addr.s_addr = inet_addr(SERVER_IP);
  ser_addr.sin_addr.s_addr = htonl(INADDR_ANY);  //注意网络序转换
  ser_addr.sin_port = htons(SERVER_PORT);        //注意网络序转换

  socklen_t          len;
  struct sockaddr_in src;
  while (1) {
    char buf[BUFF_LEN] = "TEST UDP MSG!\n";
    len = sizeof(*(struct sockaddr*)&ser_addr);
    printf("client:%s\n", buf);  //打印自己发送的信息
    sendto(client_fd, buf, BUFF_LEN, 0, (struct sockaddr*)&ser_addr, len);
    memset(buf, 0, BUFF_LEN);
    recvfrom(client_fd, buf, BUFF_LEN, 0, (struct sockaddr*)&src, &len);  //接收来自server的信息
    printf("server:%s\n", buf);
    sleep(1);  //一秒发送一次消息
  }

  close(client_fd);

  return 0;
}