Network Packet Analyzer CLI

Advanced Network Packet Analyzer: libpcap Implementation in C

Project Description:
Develop a high-performance command-line network packet analyzer using the libpcap library in the C programming language. The primary goal is to create a versatile tool capable of capturing, filtering, analyzing, and exporting network traffic across various protocols and interfaces.

Key Features:

1. Network Capture and Filtering:

   • Implement packet capture from multiple network interfaces with support for promiscuous mode.
   • Include a flexible filtering system using libpcap filters that can be defined by the user.
   • Enable real-time filtering with efficient matching algorithms.

2. Protocol Analysis:

   • Develop protocol-specific analysis routines for common protocols, including:
     • Transmission Control Protocol (TCP) - synchronize and analyze TCP flags, window sizes, and retransmissions.
     • User Datagram Protocol (UDP) - identify UDP-based applications and services.
     • Hypertext Transfer Protocol (HTTP) - parse and extract HTTP headers, methods, status codes, and response sizes.
     • Domain Name System (DNS) - analyze DNS queries, responses, and record types.
     • Other relevant protocols such as ICMP, ARP, and DHCP.
   • Implement protocol detection and classification algorithms.

3. Traffic Statistics:

   • Calculate and display real-time traffic statistics, including:
     • Total bandwidth usage (bytes per second).
     • Connection counts by protocol, source, and destination.
     • Top talkers (source and destination IP addresses with byte counts).
     • Protocol distribution.
   • Provide customizable statistics intervals.

4. Packet Decoding and Header Information:

   • Develop a detailed packet decoding system that parses and displays:
     • Ethernet headers (destination, source, type).
     • IP headers (version, header length, TOS, ID, flags, fragment offset, TTL, protocol, source, and destination IP addresses).
     • TCP headers (source and destination ports, sequence number, acknowledgment number, data offset, reserved bits, flags, window size, urgent pointer, options).
   • Include support for customizable and extensible header formats.

5. Export Functionality:

   • Implement export options for captured packets in both PCAP (libpcap format) and CSV (comma-separated values) formats.
   • Provide customizable export fields and options.
   • Ensure efficient and fast export performance.

6. Alert System for Suspicious Activity:

   • Develop an alert system capable of detecting and notifying the user about potential security threats, such as:
     • Suspicious traffic patterns (e.g., high volume of one-way traffic, unusual protocol usage).
     • Potential network attacks (e.g., SYN flooding, port scanning).
     • Anomalous network behavior.
   • Implement alert thresholds and customizable alert levels.
   • Include alert output in the console and optionally to a log file or external system.

7. Connection Tracking and State Information:

   • Maintain an active connection tracking system that records:
     • Connection ID (source and destination IP, protocol, port).
     • Connection state (opened, established, closed).
     • Connection duration.
     • Data transfer statistics (bytes sent and received).
   • Provide a mechanism to query and display connection information.

8. Geolocation Lookup for IP Addresses:

   • Integrate an IP geolocation lookup system that retrieves:
     • Country code.
     • City (if available).
     • Latitude and longitude.
   • Use a public geolocation API or database for the lookup functionality.
   • Display geolocation information alongside IP addresses in the output.

Additional Requirements:

• Implement a user-friendly command-line interface with clear syntax and sensible defaults for common options.
• Support both single- and multi-line command input for complex filter expressions.
• Provide color-coded output for better readability and visual distinction between protocol types, alert levels, and connection states.
• Ensure efficient memory management and resource allocation for large-scale packet capture.
• Include error handling and validation for command-line arguments.
• Provide a clear and concise manpage or help documentation.

Constraints and Design Considerations:

• The application should be designed to handle high packet rates (100,000+ packets per second) without excessive CPU usage.
• The code should be modular and follow a structured programming approach for easy maintenance and extension.
• The implementation should be compatible with common Linux distributions (Ubuntu, CentOS, etc.) and require minimal dependencies.
• The application should be able to run as a background process and support logging to a file for long-term monitoring.
• The user interface should be designed with both experienced network administrators and non-technical users in mind, balancing power and ease of use.

By addressing these requirements and constraints, you will create a comprehensive, efficient, and user-friendly network packet analyzer that meets the needs of both technical users and network administrators.