rscap

rscap - Rust packet capture and manipulation library

rscap is a multi-purpose library for network packet capture/transmission and packet building. Its aims are twofold:

1. To provide Rust-native cross-platform APIs for packet capture and transmission (comparable to libpcap, but written from the ground up in Rust)
2. To expose a robust and ergonomic API for building packets and accessing/modifying packet data fields in various network protocols (like scapy, but with strong typing and significantly improved performance)

The rscap submodule focuses specifically on (1)--it provides safe, Rust-native APIs for capturing packets over network interfaces. The sibling pkts crate handles building/dissecting specific protocols and packet types (2).

Development Status

Supported:

• Linux link/network/transport-layer sockets (RX + TX)
• Linux memory-mapped socket I/O (RX + TX)
• *BSD/MacOS link-layer /dev/bpf packet capture/transmission interfaces (RX + TX)
• FreeBSD /dev/bpf memory-mapped packet capture (RX only)
• Windows npcap driver packet capture/transmission (RX + TX)
• Unifying interface to provide common features in a cross-platform manner
• Creating and attaching very basic BPF programs to sockets (e.g. accept all/deny all)

In Progress:

• Compiling/assmbling more advanced filter programs (BPF)
• Solaris/IllumOS support via DLPI/PF_SOCKET//dev/bpf (RX + TX)
• Native Windows 10/11 capture support via reverse-engineered ioctl calls from pktmon (RX only)

Features

• Platform-independent interface for packet capture/transmission: rscap aims to provide a single unified interface for capturing and transmitting packets across any supported platform. Additionally, the library exposes safe abstractions of platform-specific packet capture tools (such as AF_PACKET/PACKET_MMAP sockets in Linux) to support cases where fine-grained control or platform-specific features are desired.
• Robust APIs for building/modifying packets: the pkts submodule provides simple operations to combine various layers into a single packet, and to index into a different layers of a packet to retrieve or modify fields. Users of scapy may find the API surprisingly familiar, especially for layer composition and indexing operations:

use layers::{ip::Ipv4, tcp::Tcp};

let pkt = Ip::new() / Tcp::new();
pkt[Tcp].set_sport(80);
pkt[Tcp].set_dport(12345);

• Packet defragmentation/reordering: In some protocols, packets may be fragmented (such as IPv4) or arrive out-of-order (TCP, SCTP, etc.). rscap overcomes both of these issues through Sequence types that transparently handle defragmentation and reordering. Sequence types can even be stacked so that application-layer data can easily be reassembled from captured packets. They even work in no-std environments with or without alloc.
• Stateful packet support: Many network protocols are stateful, and interpreting packets from such protocols can be difficult (if not impossible) to accomplish unless information about the protocol session is stored. rscap provides Session types that handle these kinds of packets--Sessions ensure that packets are validated based on the current expected state of the protocol. Just like Sequence, Session types are compatible with no-std environments and do not require alloc.

License

This project is licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE)

• MIT License (LICENSE-MIT)

at your option.

Contributing

rscap is open to contribution--feel free to submit an Issue or Pull Request if there's something you'd like to add to this library.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in rscap by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.