HP Rp7410 BSD Sockets Interface Programmer's Guide - Page 171

Programming Hints Adding a Server Process to the Internet Daemon exit (0); } /* * S E R V E R . U D P * * This is a variation of the example program called serv.udp. * This one performs the same function, except that it is * designed to be called from /etc/inetd. This version does * not contain a daemon loop, and does not wait for requests * to arrive on a socket. /etc/inetd does these functions. The * server simply assumes the socket to receive the message * from and send the response to is file descriptor 0 when * the program is started. It also assumes that the client's * request is already ready to be received from the socket. * */ #include #include #include #include #define BUFFERSIZE 1024 /* max size of packets to be received */ int cc; /* contains the number of bytes read */ char buffer[BUFFERSIZE]; /* buffer for packets to be read into */ struct hostent *hp; /* pointer to info for requested host */ struct sockaddr_in clientaddr_in;/* for client's socket address */ struct in_addr reqaddr; /* for requested host's address */ #define ADDRNOTFOUND 0xffffffff /* return address for unfound host */ main() { M A I N This routine receives the request and returns an answer. Each request consists of a host name for which the requester desires to know the internet address. The server will look up the name in its /etc/hosts file, and return the internet address to the client. An a internet address value of all ones will be returned if the host name is not found. int addrlen; /* clear out address structure */ memset ((char *)&clientaddr_in, 0, sizeof(struct sockaddr_in)); /* Note that addrlen is passed as a pointer * so that the recvfrom call can return the * size of the returned address. */ addrlen = sizeof(struct sockaddr_in); /* This call will * return the address of the client, * and a buffer containing its request. Chapter 8 171