116 lines
4.2 KiB
Markdown
116 lines
4.2 KiB
Markdown
# UDP broadcast
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## Introduction
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The UDP broadcast code is used to handle incoming UDP datagrams.
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there are currently 2 types of datagrams it processes:
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- broadcasts: "Where are you?v1.0", replies with current owner details.
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- change of details: "func1:name: ..., surname: ...", replies with changed owner details.
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It also writes the current owner's name on the screen and updates it everytime it's changed.
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## Table of contents
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- [Introduction](#introduction)
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- [Table of contents](#table-of-contents)
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- [Usage of UDP broadcast](#usage-of-udp-broadcast)
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- [Initialization of UDP broadcast](#initialization-of-udp-broadcast)
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- [Initialization of UDP connection](#initialization-of-udp-connection)
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- [Owner details interface](#owner-details-interface)
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- [Setting owner details](#setting-owner-details)
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- [Getting owner details](#getting-owner-details)
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## Usage of UDP broadcast
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### Initialization of UDP broadcast
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The 'udp_broadcast_init(uint16_t x_pos, uint16_t y_pos)' function does 4 things:
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1. It initializes the coördinates of where the owner's name has to be written on the LCD.
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2. [It initializes the UDP connection](#initialization-of-udp-connection)
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3. It initializes the owner's details with a default name.
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4. Returns the error value of [udp_broadcast_connection_init()](#initialization-of-udp-connection). This way the user can use some code to check whether the "connection" was initialized correctly.
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```c
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#include "UDP_broadcast.h'
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...
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void main(void){
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...
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if (udp_broadcast_init(270,255) != ERR_OK){
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...
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}
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...
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}
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```
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### Initialization of UDP connection
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The 'udp_broadcast_connection_init()' funciton does 2 things:
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1. Initializes the UDP "connection" so that incoming datagrams can be processed and replied to. It binds to port 64000 and listens to every IP-address in the local network.
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2. returns the LWIP error code so that [err_t udp_broadcast_init(uint16_t x_pos, uint16_t y_pos)](#initialization-of-udp-broadcast) knows the "connection" is initializes correctly
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This function can be used seperately from [err_t udp_broadcast_init(uint16_t x_pos, uint16_t y_pos)](#initialization-of-udp-broadcast), this gives the possibility to try "connecting" again after the first time failed.
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```c
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#include "UDP_broadcast.h'
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...
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void main(void){
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...
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if (udp_broadcast_init(10,255) == ERR_OK){
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goto connected;
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}
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LOG_WARN(TAG,"error initializing udp connection, trying again in 500ms");
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HAL_Delay(500);
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if(udp_broadcast_connection_init() != ERR_OK){
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LOG_WARN(TAG,"error initializing udp connection, check warnings from udp_broadcast_init() or udp_broadcast_connection_init()");
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}
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connected:
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...
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}
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```
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### Owner details interface
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The interface to ask for the owner's details and change them is a modified version of the [Qt application](https://github.com/wimdams/Device_finder) Wim Dams build. His only has the functionality to ask for the owner's details.
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Just because the owner's details might want to be used in other code, some functions have been written for obtaining these in the STM32 code aswell.
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#### Setting owner details
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THe 'udp_broadcast_set_owner_details(const char* , const char*)' function does 2 things:
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1. Set the owner details, the order of the parameters is: name, surname
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2. Return 1 if the owner's details have been set correctly and 0 if not.
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```c
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#include "UDP_broadcast.h'
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...
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void main(void){
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...
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if (udp_broadcast_set_owner_details("Joran", "Van Nieuwenhoven") != ERR_OK){
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...
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}
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...
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}
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```
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#### Getting owner details
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There are 3 functions:
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- udp_broadcast_get_owner_details_name(): returns the owner's name.
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- udp_broadcast_get_owner_details_surname(): returns the owner's surname.
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- udp_broadcast_get_owner_details_reply(): returns what would be replied to a UDP broadcast with datagram "Where are you?v1.0".
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```c
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#include <string.h>
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#include "UDP_broadcast.h'
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...
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void main(void){
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...
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char name[20];
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char surname[20];
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char reply[120];
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strncp(name, udp_broadcast_get_owner_details_name(), sizeof(name) - 1);
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strncp(surname, udp_broadcast_get_owner_details_surname(), sizeof(surname) - 1);
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strncp(reply, udp_broadcast_get_owner_details_reply(), sizeof(reply) - 1);
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...
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}
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``` |