Computer Networks Project

---

• Building a P2P file-sharing software like BitTorrent.
• About 800 line for midpoint check on March 10
• Final Submission 4/20

Catalog

• Computer Networks Project
  • Catalog
  • How to test?
  • How to manually run on remote server?
  • Where is the log? How to check?
  • Classes
    • 5. ActualMsg
      • receive msg
      • send msg
    • 6. FileManager
      • Block & Bit field functions
      • File functions
      • Other functions
    • 7. LogHandler
      • Project description log functions
      • Error log functions
      • Other log functions

How to test?

Please follow the cmd below, and use the cmd in script if needed any adjustment.

Before running the script, please put the configurations and the default file directories in the path of

• ~/final_project/demo/

If the debug in peerProcess is true, the program will it reads PeerInfo_local.cfg in the config path.

In this mode, all peers will build locally with different port.

1. compile

   sh ~/final_project/compileProcess.sh
   

   The java class will be established at ~/final_project/project/

2. start process

   sh ~/final_project/test/startPeers.sh

   Wait till all nodes, showing

3. kill process if needed

   sh ~/final_project/test/killAllPeer.sh
   

4. check the files result by using diff command or use the script below

   sh ~/final_project/test/checkFileDiff.sh
   

   It should not show any output which means the file are all the same.

How to run on remote server?

When you login into the server on csie, you could use these command to start the peer manually.

Be aware that the configurations to remain in

• ~/final_project/{target_file}/
• {target_file} = demo in default, change it if necessary.

1. Compile the project - use script or javac directly

   sh ~/final_project/compileProcess.sh
   

   javac -Xlint -d [target_file] src/PeerProcess.java src/peer/* src/utils/*
   

2. Compile remote deployer

   sh ~/final_project/demo/compileDeployer.sh
   

3. Start the deployment

   java ~/final_project/demo/StartRemotePeer
   

4. Kill process on ubuntu if needed

   ps aux | grep java | grep PeerProces | awk '{print $2}' | xargs /bin/kill
   

Where is the log? How to check?

The log is stored in ~/final_project/{target_file}/log, with specific file names. The logs are seperate into debug level and info level, which the former one contains every level logs, and the latter one only contains info level (logs request by project description).

• default {target_file} = demo, where we compiled the project

Here is a example, the file name is debug_log_peer_[1001]_[2021-04-13].log. With FINE and INFO level logs record in the file.

[2021-04-13 12:24:21] [FINE] [utils.LogHandler] Peer [1001] Peer [1001] receive Handshake success from [1008]
[2021-04-13 12:24:21] [FINE] [utils.LogHandler] Peer [1001] Peer [1001] check if [1008] is neighbor
[2021-04-13 12:24:21] [FINE] [utils.LogHandler] Peer [1001] (server thread) # 2 client is connected
[2021-04-13 12:24:21] [INFO] [utils.LogHandler] Peer [1001] (server) sending handshake message to peer [1008]

The logs are seperate into 3 files for each node.

• error - with only [SEVERE] Level record inside

• info - with only [INFO] Level record inside

• Debug - with only [Debug] Level record inside

Classes

1. PeerProcess (YiMing)
2. Server (YiMing)
3. Client (YiMing)
4. HandShakeMsg (YiMing)
5. ActualMsg (Jim)
6. FileManager (Jim)
7. LogHandler (YiMing)

5. ActualMsg

Class ActualMsg categorize the type of the msg and serialize them into object.

a. noPayloadMsg

• end, choke, unchoke, interested and not interested

b. shortMsg

• have, request contains 4 bytes payload
• have
  • payload = 4-byte piece index field.
  • sender uses payload to inform receiver it's properties.
• request
  • payload = 4-byte piece index field
  • receiver request piece x from sender, which x represents by payload.

c. bitfieldMsg

• bitfield
  • contains variable length bitfield
  • every byte is 8 bit which represents 8 different pieces of file.
  • For example, first byte = 3 --> 00000110. (pieces = blockIdx 0 ~ 7) Sender contains peices with blockIdx = 1 and 2.

d. pieceMsg

• piece
  • payload consists of a 4-byte piece index field and the content of the piece.

receive msg

Function Names	input	return	description
recv	InputStream in	byte type	tranform input stream

send msg

Function Names	input	return	description
send	OutputStream out, byte type, int blockIdx	None	use for noPayloadMsg and shortMsg
send	OutputStream out, byte type, byte[] bitfield	None	use for bitfieldMsg
send	OutputStream out, byte type, int blockIdx, byte[] data	None	use for pieceMsg

6. FileManager

FileManager is a singleton, new it as the class's default variables. Then you are able to call it's functions shown in the function list.

Block & Bit field functions

Function Names	input	return	description
insertBitfield	int peerId, byte[] b, int len	None	record what peices does others have
updateHave	String peerId, int blockIdx	None	update others' have peices
buildOwnBitfield	int remainderBits	None	Build own bit field record in memory
updateOwnBitfield	int blockIdx	None	update own bit field
getOwnBitfield		None	get own bit field
pickInterestedFileBlock	String peerId	int blockIdx	use for request msg, random pick a interested block which the other peer (peerId) have
isInterested	String peerId	boolean	interested in target Peer's blocks

File functions

Function Names	input	return	description
read	int blockIdx, byte[] b, int len	int byteRead	read the block, return the length of bytes which just be read
write	int blockIdx, byte[] b, int len	int byteWrite	write the block, return the lenght of bytes which just be written
close		None	close the file

Other functions

Function Names	input	return	description
isComplete		None	is peer finishing download the file
printByteArray	byte[] bytes	None	print bytes to string

7. LogHandler

• LogHandler is a singleton, new it as the class's default variables. Then you are able to call it's functions shown in the function list.

    LogHandler logging = new LogHandler();
    ...
    logging.writeLog("This is a test log");
  

• Please naming the functions with this rule

    log{Actions}
  

Project description log functions

---

Function Names	input	return	description
logStartConn	Peer client, Peer targetHost	None	log start connection
logChangePrefersPeers	None	None	log change of preferred neighbors
logChangeUnchokedPeer	None	None	change of unchoke neighbors
logUnchoking	Peer sender	None	log unchoke targe peer
logChoking	Peer sender	None	log choke target peer
logReceiveHaveMsg	Peer sender	None	log server send have msg
logReceiveInterestMsg	Peer sender	None	log cleint send interest msg
logReceiveNotInterestMsg	Peer sender	None	log cleint send not interest msg
logDownload	Peer sender, int blockIdx, int numBlocks	None	log download block
logCompleteFile	None	None	log complete downloading the file
logCloseConn	Peer targetPeer	None	log close connection
logSendHandShakeMsg	String targetPeerID, String threadType	None	log send hand shake msg

Error log functions

---

Function Names	input	return	description
logConnError	(Peer client, Peer targetHost)	None	Connection Error