一个简单的客户端与服务器通讯.doc

Linux2?007-09-19 21:15:32C/C+LinuxBS2. TCPLinux(socket).socket,linux.2.1 socketint socket(int domain, int type,int protocol)domain:(AF_UNIXAF_INET).?AF_UNIXUnix,AF_INETInternet, ( man socket domain PF_*AF_*,glibcposixPFAF,).type:(SOCK_STREAM,SOCK_DGRAM) SOCK_STREAMTCP,. SOCK_DGRAM UDP,.protocol:type,0 socket.,-1,error.2.2 bind?, (listen(),) connect(), , bind() :int bind(int sockfd, struct sockaddr *my_addr, int addrlen)sockfd:socket.addrlen:sockaddr.my_addr:sockaddr. sockaddrstruct sockaddrunisgned short as_family;char sa_data14;,(struct sockaddr_in) .sockaddr_instruct sockaddr_inunsigned short sin_family;unsigned short int sin_port;struct in_addr sin_addr;unsigned char sin_zero8;Internetsin_familyAF_INET,sin_addrINADDR_ANY,sin_port.sin_zero8. bindsocket.0,socket2.3 listen?, , :,-listen(),-accept() ( ), listen int listen(int sockfd, int backlog);sockfd socket() backlog ? (accept() ) 20,510,-1, errno, listen() bind() , :socket();?bind();listen();?/* accept() */2.4 accept?, accept() ! : (listen() (connect() (accept() accept() !, (send() ( recv() !int accept(int sockfd, struct sockaddr *addr,int *addrlen)sockfd:listen.addr, addrlen,.?bind,listenaccept,accept, .?accept,. -12.5 connectint connect(int sockfd, struct sockaddr * serv_addr,int addrlen)sockfd:socket.serv_addr:.sin_addaddrlen:serv_addrconnect.0,sockfd -1.? telnet socket(), 23( telnet )0? ,connect()- connect() :#include #include int connect(int sockfd, struct sockaddr *serv_addr, int addrlen);sockfd socket() serv_addr IP structsockaddraddrlen sizeof(struct sockaddr)?:#include #include #include #define DEST_IP 0?#define DEST_PORT 23main()int sockfd;struct sockaddr_in dest_addr; /* */sockfd = socket(AF_INET, SOCK_STREAM, 0); /* */dest_addr.sin_family = AF_INET; /* host byte order */dest_addr.sin_port = htons(DEST_PORT); /* short, network byte order */dest_addr.sin_addr.s_addr = inet_addr(DEST_IP);bzero(&(dest_addr.sin_zero),; /* zero the rest of the struct */* dont forget to error check the connect()! */connect(sockfd, (struct sockaddr *)&dest_addr, sizeof(struct sockaddr);.2.6:socket:int int, : ( octet, ) , (Network Byte Order), NBO ,( htons() ) (Host Byte Order) NBO, (TM)-struct sockaddr. :struct sockaddr unsigned short sa_family; /* , AF_xxx */char sa_data14; /*14*/;sa_family , AF_INET sa_data struct sockaddr,: struct sockaddr_in (in Internet)struct sockaddr_in short int sin_family; /* */unsigned short int sin_port; /* */struct in_addr sin_addr; /* Internet */unsigned char sin_zero8; /* sockaddr*/; sin_zero (, structsockaddr ) bzero() memset() , sockaddr_insockaddr socket() struct sockaddr *, struct sockaddr_in, sin_family struct sockaddr sa_family AF_INET,sin_port sin_addr (Network Byte Order)!:, struct in_addr sin_addr ? , : struct in_addr, (unions):/* Internet () */struct in_addr unsigned long s_addr;, ina struct sockaddr_in ,ina.sin_addr.s_addr 4 IP () struct in_addr ,4 IP (#define)struct hostent? struct hostent ? char *h_name;? char *h_aliases;? int h_addrtype;? int h_length;? char *h_addr_list;? ;? ?define h_addr h_addr_list0 ? ?struct hostent: ?h_name ? ?h_aliases ? -?h_addrtype ?; AF_INET ?h_length ? ?h_addr_list ? -?h_addr - h_addr_list?2.7? ,!: short () long () unsigned short h (host), to, n (network), s short: h-to-n-s, htons() (Host to Network Short).,n,h,s, l ,stolh() (Short toLong Host) , ,:htons()-Host to Network Short?htonl()-Host to Network Long?ntohs()-Network to Host Short?ntohl()-Network to Host Long,: char ? , : 68000 , htonl() IP , ,! Unix !: ,: struct sockaddr_in , sin_addr sin_port ,sin_family ? : sin_addr sin_port IP UDP , sin_family (kernel) , sin_family ,2.8 /* (server.c) */* Name:server.c* Used to study the network programming in Linux OS.* Showing how to use the functions,* like socket,bind,listen,accept and write.* This is the server program.* Author:zeickey* Date:2006/9/16 ?* Copyright (c) 2006,All Rights Reserved!*/#include #include #include #include #include #include #include #include int main(int argc, char *argv)int sockfd,new_fd;struct sockaddr_in server_addr;struct sockaddr_in client_addr;int sin_size,portnumber;char hello=Hello! Are You Fine?n;?if(argc!=2)?fprintf(stderr,Usage:%s portnumberan,argv0);?return 1;?if( (portnumber = atoi(argv1) 0 )?fprintf(stderr,Usage:%s portnumberan,argv0);?return 1;?/* socket */?if( (sockfd = socket(AF_INET,SOCK_STREAM, 0) = -1 )?fprintf(stderr,Socket error:%sna,strerror(errno);?return 1;?/* sockaddr */?/bzero(&server_addr, sizeof(struct sockaddr_in);?memset(&server_addr, 0, sizeof(struct sockaddr_in);?server_addr.sin_family = AF_INET;?server_addr.sin_addr.s_addr = htonl(INADDR_ANY);?server_addr.sin_port = htons(portnumber);?/* sockfdlisten */?if( bind(sockfd,(struct sockaddr *)(&server_addr),sizeof(struct sockaddr)=-1 )?fprintf(stderr,Bind error:%sna,strerror(errno);?return 1;?/* sockfd */?if( -1 = listen(sockfd,5) )?fprintf(stderr,Listen error:%sna,strerror(errno);?return 1;?while(1)?/* , */?sin_size=sizeof(struct sockaddr_in);?/if( (new_fd = accept(sockfd, (struct sockaddr *)(&client_addr), &sin_size) = -1)?new_fd = accept(sockfd, (struct sockaddr *)(&client_addr), &sin_size);?if( -1 = new_fd )?fprintf(stderr,Accept error:%sna,strerror(errno);?return 1;?fprintf(stderr,Server get connection from %sn, inet_ntoa(client_addr.sin_addr);?if(write(new_fd,hello,strlen(hello)=-1)?fprintf(stderr,Write Error:%sn,strerror(errno);?return 1;?/* */?close(new_fd);?/* */?close(sockfd);?return 0;/* client.c */*?Name:client.c*?Used to study the network programming in Linux OS.*?Showing how to use the functions,* like socket,bind,listen,accept and write.*?This is the client program.*?Author:zeickey*?Date:2006/9/16?*?Copyright (c) 2006,All Rights Reserved!*/#include #include #include #include #include #include #include int main(int argc, char *argv)?int sockfd;?char buffer1024;?struct sockaddr_in server_addr;?/struct hostent *host;?char *ip;?int portnumber,nbytes;?if(argc!=3)?fprintf(stderr,Usage:%s ip portnumberan,argv0);?return 1;?/if(host=gethostbyname(argv1)=NULL)?printf(agrv1 = %sn,argv1);?if( strlen(ip=argv1) 7 )?fprintf(stderr,Get Ip address errorn);?return 1;?if(portnumber=atoi(argv2)h_addr );?/server_addr.sin_addr.s_addr = inet_addr(host-h_addr);?server_addr.sin_addr.s_addr = i