Intro. to Network Programming, lectured by Chun-Ying Huang
In this project, I designed a Bulletin Board System(BBS) server. This program runs in single process and use select() to handle multiple connections (users). Client connect to the server by TCP connection, while chat with UDP connection and special packet form.
ubuntu 20.04
g++ 14
All exceptions are handled.
- register <username> <password>
Register with username and password. - login <username> <password>
Login with username and password. - logout
Logout account. - whoami
Show your username. - list-user
List all users in BBS. - exit
Close connection.
- send <username> <message>
leave message to a user. - list-msg
list the message state of Message Box. - receive <username>
Show the first message from , and pop the message.
-
create-board <name>
Create a board which named <name>. -
create-post <board-name> --title <title> --content <content>
Create a post which title is <title> and content is <content>. -
list-board
List all boards in BBS. -
list-post
List all posts in a board named <board-name> -
read <post-S/N>
Show the post which S/N is <post-S/N>. -
delete-post <post-S/N>
Delete the post which S/N is <post-S/N>. -
update-post <post-S/N> --title/content
Update the post which S/N is <post-S/N>.
- enter-chat-room <port> <version>
Enter a chat room. - chat <message>
send the messages by UDP packets.
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 (bits)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| flag | version |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| length of name |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ name +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| length of message |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ message +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Name | Size | Description |
|---|---|---|
| flag | 8 bits | it must be 0x1 |
| version | 8 bits | it must be 0x1 |
| length of name | 16 bits | length of message in big endian |
| name | strlen(name) * 8 bits |
|
| length of message | 16 bits | length of message in big endian |
| message | strlen(message) * 8 bits |
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 (bits)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| flag | version |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ +
| |
+ +
| name |
+ +-+-+-+-+-+-+-+-+
| | separator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ +
| |
+ +
| message |
+ +-+-+-+-+-+-+-+-+
| | separator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Name | Size | Description |
|---|---|---|
| flag | 8 bits | its must be 0x1 |
| version | 8 bits | it must be 0x2 |
| name | strlen(base64(name)) * 8 bits |
name encoded in base64 |
| separator | 8 bits | it must be '\n' |
| message | strlen(base64(message)) * 8 bits |
message encoded in base64 |
| separator | 8 bits | its value is '\n' |
When a user joins the public (enter-chat-room) chat room, the server should immediately encapsulate all messages in chat history in the format of <chat_history> and sends it to the client in the TCP connection.
To keep our chat room a place filling with joy and happiness, some keywords should not be used. Below is the filtering list of those keywords. The server must mask each matched word in <message> sent by the chat command by replacing the word with a string of * characters of equal length.
Hard coded filtering list in C/C++ program file.