Network Clients - Java - page 526

return return ;

}
iif ( debug )
System . err . println ( "Got packet of size " +
inp . getLength ());

/* Print the data from the packet */
System . out . write ( buffer , 4 , inp . getLength ()- 4 );

/* Ack the packet. The block number we
* want to ack is already in buffer so
* we just change the opcode. The ACK is
* sent to the port number which the server
* just sent the data from, NOT to port
* TFTP_PORT.
*/
buffer [ OFFSET_REQUEST ] = OP_ACK ;
outp . setLength ( 4 );
outp . setPort ( inp . getPort ());
sock . send ( outp );
} while while ( inp . getLength () == PACKET_SIZE );

iif ( debug )
System . err . println ( "** ALL DONE** Leaving loop, last size " +
inp . getLength ());

}

}

To test this client, you need a TFTP server. If you are on a Unix system that you administer,
you can enable the TFTP server to test this client just by editing the file /etc/inetd.conf and
restarting or reloading the inetd server. inetd is a program that listens for a wide range of
connections and starts the servers only when a connection from a client comes along (a kind
of lazy evaluation). [ 43 ] I set up the traditional /tftpboot directory, put this line in my in-
etd.conf , and reloaded inetd :

tftp dgram udp wait root /usr/libexec/tftpd tftpd -s /tftpboot

Then I put a few test files, one named foo , into the /tftpboot directory. Running:

$ java network.RemCat localhost foo