RHEL6 scp（ssh 拷贝、传输文件）

linux下UDP 客户端和服务端程序示例,使用recvfrom与sendto函数
程序转自hoyt的<Linux网络编程>,解决了作者的client端收不到数据的情况,但因为联系不到作者,只好在此贴出,如果有哪位朋友可以代我通知作者的或告诉我作者联系方式的话,本人不胜感激.
原程序错误原因:server端使用recvfrom()前为将用来标识记录地址的sockadd_in addr的addrlen为初始化,导致server端解析地址错误.
解决方法:将addrlen初始化为sizeof(addr)




/**//**********UDP服务端程序UDPserver.c***********/


#include <sys/types.h>


#include <sys/socket.h>


#include <netinet/in.h>


#include <arpa/inet.h>


#include <unistd.h>


#include <stdio.h>


#include <stdlib.h>


#include <errno.h>


#include <string.h>




#define SERVER_PORT 8888


#define MAX_MSG_SIZE 1024






void udps_respon(int sockfd) ...{


struct sockaddr_in addr;


unsigned int addrlen;


int n;


char msg[MAX_MSG_SIZE];






while(1) ...{


// 从网络上读,写到网络上去


// 初始化addr长度!


addrlen = sizeof(addr);


if((n = recvfrom(sockfd,msg,MAX_MSG_SIZE,0,




(struct sockaddr *)&addr,&addrlen)) < 0) ...{


fprintf(stderr,"Recveive packahe error:%s",


strerror(errno));


continue;


}


msg[n - 1] = '';


// 显示服务器端已经收到了信息


fprintf(stdout,"I have received %s from %sn",msg,


inet_ntoa(addr.sin_addr));


sendto(sockfd,msg,n,0,(struct sockaddr *)&addr,addrlen);


}


}






int main(void) ...{


int sockfd;


struct sockaddr_in addr;


sockfd = socket(AF_INET,SOCK_DGRAM,0);




if(sockfd < 0) ...{


fprintf(stderr,"Socket Error:%sn",strerror(errno));


exit(1);


}




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);




if(bind(sockfd,(struct sockaddr *)&addr,




sizeof(struct sockaddr_in)) < 0) ...{


fprintf(stderr,"Bind Error:%sn",strerror(errno));


exit(1);


}




udps_respon(sockfd);


close(sockfd);


exit(1);


}






/**//*****UDP客户端程序UDPclient.c********/


#include <sys/types.h>


#include <sys/socket.h>


#include <netinet/in.h>


#include <arpa/inet.h>


#include <errno.h>


#include <stdio.h>


#include <stdlib.h>


#include <string.h>


#include <unistd.h>




#define MAX_BUF_SIZE 1024






void udpc_request(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


fgets(buffer,MAX_BUF_SIZE,stdin);


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


bzero(buffer,MAX_BUF_SIZE);


// 从网络上读,写到屏幕上


n = recvfrom(sockfd,buffer,MAX_BUF_SIZE,0,NULL,NULL);


buffer[n - 1] = '';


fprintf(stdout,"I received %s from server.n",buffer);


}


}






int main(int argc,char **argv) ...{


int sockfd,port;


struct sockaddr_in addr;






if(argc != 3) ...{


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


exit(1);


}




if((port = atoi(argv[2])) < 0) ...{


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


exit(1);


}




sockfd = socket(AF_INET,SOCK_DGRAM,0);




if(sockfd < 0) ...{


fprintf(stderr,"Socket Error:%sn",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(port);




if(inet_aton(argv[1],&addr.sin_addr) < 0) ...{


fprintf(stderr,"IP error:%sn",strerror(errno));


exit(1);


}


udpc_request(sockfd,&addr,sizeof(struct sockaddr_in));


close(sockfd);


exit(0);


}