// you must have initialized info_data_len at some time before calling this function
//
// This info_data_len initialisation is done automatically if you call
// packetloop_icmp_tcp(buf,enc28j60PacketReceive(BUFFER_SIZE, buf));
// and test the return value for non zero.
//
// dlen is the amount of tcp data (http data) we send in this packet
// You can use this function only immediately after make_tcp_ack_from_any
// This is because this function will NOT modify the eth/ip/tcp header except for
// length and checksum
void www_server_reply(uint8_t *buf,uint16_t dlen)
{
        make_tcp_ack_from_any(buf,info_data_len,0); // send ack for http get
        // fill the header:
        // This code requires that we send only one data packet
        // because we keep no state information. We must therefore set
        // the fin here:
        buf[TCP_FLAGS_P]=TCP_FLAGS_ACK_V|TCP_FLAGS_PUSH_V|TCP_FLAGS_FIN_V;
        make_tcp_ack_with_data_noflags(buf,dlen); // send data
}