Arp

Learning about arp protocol and some network stuff

Minor Refactoring

Just did some minor refactoring in the cleanup branch. The goal was to simplify the archtitecture. And to kinda follow SRP but it still seems i have strong coupling

• ArpChat
  • Is the Main Object the controler
  • Is responsible to control ArpProtocol and ArpGui
• ArpGui
  • Holds now all logic for gui and only gui logic
  • SRP is fine here
• ArpProtocol
  • Is responsible to send and receive data via the ARP protocol
  • Does not care for what happens in the gui
  • Still needs some work done because the receiving of messages is still happening in main.cpp
  • At least sending packages can be done via ArpProtocol class

The communication between the GUI and the protocol is executed via a buffer called chatHistory

General

In general this little project is working and does what it should do. We can communicate with other users via the arp protocol.

Messages

The messages file contains all the layer data (EthernetFrame and Arp payload)

Currently the EthernetFrame class is responsible to parse the raw bytes into a EthernetFrame and its Arp payload, this is at the moment done in the constructor but it seems it must be moved.

• The MAC and IP addresses are saved as a std::string with the functions hexToString and ipToString.
• The function isArp is a static function to check if it is the correct etherType because we only want to interact with Arp types.
• The class EthernetFrame has a variable called payload which is the ArpPackage data (Fields taken from Wikipedia)
• The EthernetFrame fields are from Wikipedia

Sending Arp over the Network

For this we use the library libnet To identify a ArpChat message we add a prefix which is "SAND" to each message.

Current Status

Working on refactoring.

• Currently there is kinda a split going on to split responsibility between arpChat and arpGui
• Still need to split them in a better way and cleaner much cleaner
• In main there is some code which must be moved to arpGui / arpChat
• Moved Several functions from main to ArpChat class

Added

• Parsing of simple command line arguments.
• Previously in the code the network interface was hardcoded, now the user can provide it himself. If the interface can not be read we will show a list of all available network interfaces

Missing

• Automagically get Mac address of computer

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