protocol

    OpenParkingFinder - An open source parking manager and parking finder.
    Copyright (C) 2019 Louis van der Walt

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.

A decription of the TCP protocol for communication. THIS FILE IS NOT USED TO CHANGE SETTINGS, ONLY FOR REFRENCE.
Client in this context means a node, parking machine or gate. For the most part 0x0F?? = node, 0x0E?? = parking machine, 0x0D?? = gate, 0x01?? = Hub.

client to server packet structure
2       bytes   optcode
8       bytes   ID (node = 0xA0??????????????, parking machine = 0xB0??????????????, gate = 0xC0??????????????)
54      bytes   data
TOTAL SIZE = 64 bytes

server to client packet structure
2       bytes   optcode
62      bytes   data
TOTAL SIZE = 64 bytes

Optcodes

CLIENT TO SERVER ONLY
0x0F00
    Requests config data from the server.
    Arguments: 0 bytes

0x0F01
    Send information about the parkings to the hub
    Arguments: 36 bytes
        2   bytes   Parking num in row Left
        2   bytes   Parking num in row Right
        16  bytes   Number plate reading right
        16  bytes   Number plate reading left

0x0E00
    Request parking from database
    Arguments: 4 bytes
        4  bytes   Ticket no.

0x0D00
    Request ticket
    Arguments: 16 bytes
        16  bytes    Number plate reading

SERVER TO CLIENT ONLY
0x0100
    Send the position information to the node
    Arguments: 8 bytes
        4   bytes   Rail length in mm
        4   bytes   Steps per parking

0x0101
    Supply ticket no
    Arguments: 8 bytes
        4   bytes   Ticket no.
        4   bytes   Time

0x0102
    Respond w/ place parked 
    Arguments: 4 bytes
        1   bytes   parkade
        1   bytes   floor
        1   bytes   row
        1   bytes   parking

0x0200
    Error
    Arguments: 2 bytes
        2   bytes   Error code