udp_client.c udp_server.c

#include <stdlib.h>

#include <stdio.h>

#include <errno.h>

#include <string.h>

#include <unistd.h>

#include <netdb.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <sys/types.h>

#include <arpa/inet.h>



#define SERVER_PORT 8888 

#define MAX_BUF_SIZE 1024 



void udpc_requ(int sockfd,const struct sockaddr_in *addr,int len) 

{ 

    char buffer[MAX_BUF_SIZE]; 

    int n; 

    while(1) 

    {     /* 从键盘读入,写到服务端 */ 

        printf("Please input char:\n");

        fgets(buffer,MAX_BUF_SIZE,stdin); 

        sendto(sockfd,buffer,strlen(buffer),0,(struct sockaddr *)addr,len); 

        bzero(buffer,MAX_BUF_SIZE); 

    } 

} 



int main(int argc,char **argv) 

{ 

    int sockfd; 

    struct sockaddr_in addr; 



    if(argc!=2) 

    { 

        fprintf(stderr,"Usage:%s server_ip\n",argv[0]); 

        exit(1); 

    }



    /* 建立 sockfd描述符 */ 

    sockfd=socket(AF_INET,SOCK_DGRAM,0); 

    if(sockfd<0) 

    { 

        fprintf(stderr,"Socket Error:%s\n",strerror(errno)); 

        exit(1); 

    } 



    /* 填充服务端的资料 */ 

    bzero(&addr,sizeof(struct sockaddr_in)); 

    addr.sin_family=AF_INET; 

    addr.sin_port=htons(SERVER_PORT);

    if(inet_aton(argv[1],&addr.sin_addr)<0)  /*inet_aton函数用于把字符串型的IP地址转化成网络2进制数字*/ 

    { 

        fprintf(stderr,"Ip error:%s\n",strerror(errno)); 

        exit(1); 

    } 



    udpc_requ(sockfd,&addr,sizeof(struct sockaddr_in)); // 进行读写操作

    close(sockfd); 

} 







#include <stdlib.h>

#include <stdio.h>

#include <errno.h>

#include <string.h>

#include <unistd.h>

#include <netdb.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <sys/types.h>

#include <arpa/inet.h>



#define SERVER_PORT 8888 

#define MAX_MSG_SIZE 1024 



void udps_respon(int sockfd) 

{ 

    struct sockaddr_in addr; 

    int addrlen,n; 

    char msg[MAX_MSG_SIZE]; 



    while(1) 

    {    /* 从网络上读,并写到网络上 */ 

        bzero(msg,sizeof(msg)); // 初始化,清零

        addrlen = sizeof(struct sockaddr);

        n=recvfrom(sockfd,msg,MAX_MSG_SIZE,0,(struct sockaddr*)&addr,&addrlen); // 从客户端接收消息

        msg[n]=0;//将收到的字符串尾端添加上字符串结束标志 

        /* 显示服务端已经收到了信息 */ 

        fprintf(stdout,"Server have received %s",msg); // 显示消息

    } 

} 



int main(void) 

{ 

    int sockfd; 

    struct sockaddr_in addr; 



    /* 服务器端开始建立socket描述符 */ 

    sockfd=socket(AF_INET,SOCK_DGRAM,0); 

    if(sockfd<0) 

    { 

        fprintf(stderr,"Socket Error:%s\n",strerror(errno)); 

        exit(1); 

    } 



    /* 服务器端填充 sockaddr结构 */ 

    bzero(&addr,sizeof(struct sockaddr_in)); 

    addr.sin_family=AF_INET; 

    addr.sin_addr.s_addr=htonl(INADDR_ANY); 

    addr.sin_port=htons(SERVER_PORT); 



    /* 捆绑sockfd描述符 */ 

    if(bind(sockfd,(struct sockaddr *)&addr,sizeof(struct sockaddr_in))<0) 

    { 

        fprintf(stderr,"Bind Error:%s\n",strerror(errno)); 

        exit(1); 

    } 



    udps_respon(sockfd); // 进行读写操作

    close(sockfd); 

}