secdev/scapy
Scapy
Scapy is a network packet manipulation tool and protocol analysis suite designed for crafting, sending, sniffing, and dissecting network traffic. It functions as a framework for building custom network tools that interact directly with low-level packet headers and payloads, enabling users to perform security research and network diagnostics.
The system distinguishes itself through a layer-based construction model that allows users to define protocols as stacked objects, which automatically handle checksums and field offsets. It utilizes dynamic field reflection to map packet structures to binary data formats and employs a raw socket interface to bypass standard transport layer restrictions for custom packet injection.
The platform provides a comprehensive capability set for network security testing, automated scanning, and traffic simulation. It includes a protocol dissection engine that recursively parses binary streams into structured objects, supported by stateful flow tracking to correlate packets into logical sessions. Users can capture and analyze live traffic through a background sniffing loop to troubleshoot communication patterns and verify protocol implementations.