L2 Crash Receiver

A robust HTTP server for receiving and processing Lineage 2 crash reports. This application accepts multipart/form-data POST requests containing crash dump files and error descriptions, then saves them to the local filesystem for analysis.

Features

• Security: Input validation, path traversal protection, and file size limits
• Configurability: Command-line configuration for port and upload directory
• Thread Safety: Concurrent request handling with configurable thread pool
• Proper Logging: Comprehensive logging using Java logging framework
• Graceful Shutdown: Clean resource cleanup on application termination
• Java 8 Compatible: Uses only Java 8 features and standard library

Architecture

The application is organized into several components:

• L2CrashReceiver - Main entry point with command-line argument parsing
• CrashReportServer - HTTP server managing connections and lifecycle
• HttpRequestHandler - Individual request processing logic
• MultipartParser - Utility for parsing multipart/form-data
• FileService - File operations with validation and security checks
• HttpResponse - HTTP response model with proper formatting
• ServerConfiguration - Configuration management with builder pattern

Usage

Basic Usage

# Start server on default port 80 with default upload directory 'crashes/'
java l2.tools.L2CrashReceiver

# Start server on custom host, port
java l2.tools.L2CrashReceiver 0.0.0.0 80

# Start server with custom host, port and upload directory
java l2.tools.L2CrashReceiver 0.0.0.0 8080 crashes/

Building

# Build the application
./gradlew build

# Run the application
./gradlew run

# Create a JAR file
./gradlew jar

API

The server accepts POST requests to any path with the following requirements:

Request Format based on L2CrashSeder application

• Method: POST
• Content-Type: multipart/form-data
• Fields:
  • CRVersion : Version information
  • error : Error description text
  • dumpfile : Binary dump file
  • gamelog (optional): Game log file(l2.log)
  • networklog (optional): Network log file(Network.log)

Response Codes

• 200 OK: Crash report processed successfully
• 400 Bad Request: Invalid request format or missing required fields
• 413 Payload Too Large: File size exceeds configured maximum
• 500 Internal Server Error: Server-side processing error

Example Request

POST / HTTP/1.1
Content-Type: multipart/form-data; boundary=MULTIPART-DATA-BOUNDARY

--MULTIPART-DATA-BOUNDARY
Content-Disposition: form-data; name="CRVersion"

1.0.0
--MULTIPART-DATA-BOUNDARY
Content-Disposition: form-data; name="error"

Exception occurred in game engine...
--MULTIPART-DATA-BOUNDARY
Content-Disposition: form-data; name="upload_file_minidump"; filename="crash.dmp"
Content-Type: application/octet-stream

[binary dump data]
--MULTIPART-DATA-BOUNDARY--

Configuration

Default configuration values:

• Host: 0.0.0.0
• Port: 80
• Upload Directory: crashes/
• Max File Size: Integer.Max
• Thread Pool Size: 10 threads

Security Features

1. Path Traversal Protection: Prevents files from being saved outside the upload directory
2. Filename Sanitization: Removes dangerous characters from uploaded filenames
3. File Size Limits: Configurable maximum file size to prevent DoS attacks
4. Input Validation: Comprehensive validation of all input parameters
5. Resource Management: Proper cleanup of resources to prevent memory leaks

File Handling

• Crash dump files are saved with their original names (sanitized)
• Error descriptions are saved as text files with .txt extension
• Duplicate filenames are handled by appending timestamps
• All files are saved in the configured upload directory

Logging

The application uses Java's built-in logging framework with the following levels:

• INFO: Server startup, configuration, and successful operations
• WARNING: Non-fatal errors and unusual conditions
• SEVERE: Fatal errors and exceptions

Requirements

• Java 8 or higher
• Write permissions to the upload directory
• Network permissions to bind to the specified host, port