Experiment 0x1：UDP套接字编程

Experiment 0x1：UDP套接字编程

0x0 说明

实验一：TCP套接字编程或UDP套接字编程

此篇为第二部分：UDP套接字编程

记录实验课代码

代码环境：

win10

VS2019 远程连接 ubuntu20

进行linux编程

0x1 要求

要求：实现一个基于UDP协议的对等用户通信程序，要求完成以下功能。

• 通信程序：
  • 从命令行读入对等端的IP地址；
  • 与对等端实现通话和数据的屏幕回显.

0x2 实现

实现一个基于UDP协议的对等用户通信程序

0x3 源码

1- UDP服务端源码

#include<stdio.h>
#include<string.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<stdlib.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#define PORT 2333
#define MAXDATASIZE 100
int main() {int sockfd;sockaddr_in server;sockaddr_in client;sockfd = socket(AF_INET, SOCK_DGRAM, 0);if (sockfd == -1) {perror("socket() error!");_exit(1);}bzero(&server, sizeof(sockaddr_in));server.sin_family = AF_INET;server.sin_port = htons(PORT);server.sin_addr.s_addr = htonl(INADDR_ANY);int flag = bind(sockfd, (sockaddr*)&server, sizeof(server));if (flag == -1) {perror("bind() error!");_exit(1);}socklen_t len = sizeof(sockaddr_in);int num;while (1) {char buf[MAXDATASIZE];num = recvfrom(sockfd, buf, MAXDATASIZE, 0, (sockaddr*)&client, &len);if (num < 0) {perror("recvfrom() error!");_exit(1);}buf[num] = '\0';printf("You got a message <%s> from cient.\n",buf);printf("It's ip is %s, port is %d.\n\n", inet_ntoa(client.sin_addr), ntohs(client.sin_port));sendto(sockfd, buf, strlen(buf), 0, (sockaddr*)&client, len);if (!strcmp(buf, "bye")) {printf("had Disconnected, ip:%s\n", inet_ntoa(client.sin_addr));break;}}close(sockfd);return 0;
}

2- UDP客户端源码

UDP客户端源码
#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<netdb.h>
#define PORT 2333
#define MAXDATASIZE 100
int main(int argc, char* argv[]) {int sockfd;hostent* he;sockaddr_in server, peer;if (argc != 2) {printf("Usage:%s<IP Adress>\n", argv[0]);_exit(1);}he = gethostbyname(argv[1]);if (he == NULL) {perror("gethostbyname() error!\n");_exit(1);}sockfd = socket(AF_INET, SOCK_DGRAM , 0);if (sockfd == -1) {perror("socket() error!\n");_exit(1);}bzero(&server, sizeof(sockaddr_in));server.sin_family = AF_INET;server.sin_port = htons(PORT);server.sin_addr = *(in_addr*)(he->h_addr_list[0]);while (1) {char buf[MAXDATASIZE] = { 0 };printf("please input: ");gets(buf);if (strlen(buf) > 100) {printf("input too long! must less 100 bytes!\n");_exit(1);}sendto(sockfd, buf, strlen(buf), 0, (sockaddr*)&server, sizeof(sockaddr_in));socklen_t len = sizeof(sockaddr_in);int num = 0;num = recvfrom(sockfd, buf, MAXDATASIZE, 0, (sockaddr*)&peer, &len);if (num == -1) {perror("recvfrom() error!\n");_exit(1);}if (len != sizeof(sockaddr_in) || memcmp((void*)&server, (void*)&peer, len) != 0) {printf("Receive message from other server.\n");continue;}buf[num] = '\0';printf("Server Message: %s.\n\n", buf);if (!strcmp(buf, "bye")) {printf("had Disconnected!\n");break;}}close(sockfd);return 0;
}