C4数据通信--网络.pptVIP

数字通信(实训)之 客户机与服务器 的实用程序 程序功能 Client acquires user information from Remote server Client is a program that can be called on by user with Remote hostname and username info wanted 客户机 //client.cpp #include stdio.h # include sys/types.h # include sys/socket.h //A application client prog supporting whos service main(int argc, char*argv[]); { int s;//socket descriptor int len;//received data length struct sockaddr_in sa;//internet socket address struct hostent *hp;//host name lookup result; struct servent *sp;//service lookup 客户机 char buf[BUFSIZ+1]; char *myname,*host,*user;//prog name,remote user and host name myname=argv[0]; if (argc!=3) exit(1);//progname host,user host=argv[1]; user=argv[2]; //lookup hostname if((hp=gethostname(host))==NULL) //Get a 32bites address of host devided by points and decimal numbers exit(1);//no result //host’s address and type is put into socket struct bcopy((char *)hp-h_addr, (char *)sa.sin_addess,hp-h_length); sa.sin_familly=hp-h_address_type; //look up socket number for service 客户机 if (sp=getservbyname(“whois”,”tcp”)==NULL) //get port number exit(1);//no whois service on the host //put the whois socket No. Into socket structure Sa.sin_port=sp-s_port; //allocate socket If(s=socket(hp-h_addesstype,SOCK_STREAM,0)0) exit(1); //connect to the remote server If(connect(s,sa,sizeof sa)0) exit(2); //sending request 客户机 If(write(s,user,strlen(user))!=strlen(user)) exit(3); //reading reply While((len=read(s,buf,BUFSIZ))0) write(s,buf,len); Close(s);exit(0); } 服务器 在端口上监听并返回信息 //server.cpp #include stdio.h # include sys/types.h # include sys/socket.h #include netinet/in.h # include netdb.h # include ped.h //use:whois hostname,username,port43 #define BACKLOC 5 //queuing No. #define MAXHOSTNAME 32 //maximum name len main(argc,argv[]) 服务器 { int argc; char*argv[]; int s,t;//socket descriptors int i; struct sockaddr_in sa,isa;//internet socket address struct hostent *hp;//host name lookup result; struct servent *sp;//service lookup char *my