I havn't run your code, but it looks like you are using very low level socket code, and that involves alot of handshaking, which you may need improving upon. Probably, you are getting into a deadlock condition, where both sides of the socket connection are waiting to send or receive.
One quick thing to try is put newlines into all syswrites, like
# syswrite($new_sock, $buf, 10);
syswrite( $new_sock , "$buf\n\n", 10);
Another thing to try is using select ( or IO::Select) on the socket filehandles. That way you can do the read in a $select->can_read loop, which will keep the deadlock from occurring. Google for numerous Perl socket examples, like "perl socket IO::Select".
Also see the perl socket examples a basic socket tutorial