• System & Program Design • User & Operator Guide • Protocol Specification Report

Report

• Protocol Specification

• User & Operator Guide

• System & Program Design

• Problem and Solution

Protocol Specification

• Protocol Specification

• User & Operator Guide

• System & Program Design

• Problem & Solution

Protocol Specification

(1) (2) (3) (4) (5) (6)

(7)

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Protocol Specification

1. Type 2. Error

3. Self Index

4. Sender Index 5. Receiver Index 6. Data Length 7. ID

8. Password

9. Data

User & Operator Guide

• Protocol Specification

• User & Operator Guide

• System & Program Design

• Problem & Solution

Press Left or Right

Registration

Press Left to choose new

Registration

Enter ID and Password, if will auto login if succes

Login

&

Messaging

After Login, There will appear a user list and you can choose a user to send message Choose a user and press Enter.

Messaging

Press Enter to send Message.

If you want to Send multiply lines message you can Press F2 to change into Long Text Mode

Messaging

Press F1 to change back to Text Mode and press Enter to send message

Messaging(Online)

The User you sent message to will receive the message if he or she is online.

Messaging(Offline)

If the user is currently offline, he or she will receive the message when he/she login.

Messaging(Historical)

The server side will keep a log on sent and received messages for users to query.

Messages will persist after server restarts, they are stored in a file

File Transfer

Type in File name and press Enter to transfer

File Transfer

Receiver side will show these messages

File Transfer(Multiply Files)

You can keep type in the file names and they will all transfer at the same time

File Transfer(Multiply Files)

Receiver side will show these messages

Bonus : Auto Reconnect

If Sever is close, client will ask reconnecting or not

Bonus : Encryption

Using AES-128 Encryption

When sending or receiving pack, encryption or decryption it

System & Program Design

• Protocol Specification

• User & Operator Guide

• System & Program Design

• Problem & Solution

FSM Client

• while (1) {

State Decision;

Receive Requests;

User Control;

File Transfer;

• }

FSM Client (signal handler)

• void sigint_shut_down

• void sigpipe_shut_down

FSM Server

• Receive a packet

• According to packet type do different things

AES Encryption

Problem & Solution

• Protocol Specification

• User & Operator Guide

• System & Program Design

• Problem & Solution

Problem and Solution

• Problem: 用Command Line做檔案傳輸需要輸入許 多複雜指令，不夠人性化。

• Solution: 自行設計simple interface，使用直覺化，

除了測試時比較方便，新使用者也容易上手。

Problem and Solution

• Problem: 封包傳送過程會遺失或不齊全, 傳送出去 跟接收端收到的大小不同，因為我們封包大小太 大(2048 Byte)，每次傳出去後半段的封包都會遺 失。

• Solution: 將封包大小壓到1488Byte以下，封包傳

送就不會遺失了。

Problem and Solution

• Problem:封包中的data陣列如果被資料全填滿，將 會因為沒有終止字元使得讀取發生錯誤。

• Solution: 在char陣列最後面留幾個byte來存放終止

字元，問題即解決。