Standard curl has an ability to connect to a TFTP server and upload a file via:
$ curl -T FILE tftp://HOST
Download a file:
$ curl -o DESTINATION tftp://HOST/file
Edit /etc/xinetd.conf and add the following entry:
service tftp
{
socket_type = dgram
protocol = udp
wait = yes
user = tftp
server = /usr/sbin/in.tftpd
server_args = -l /tftpboot
only_from = client.test.net
}