libcrafter

A high-level C++ library for crafting, decoding, and manipulating network packets.

Overview

libcrafter is a network packet manipulation library for C++ that provides an intuitive, Scapy-like interface for creating and analyzing network traffic. It enables developers to build powerful networking tools with minimal code by representing packets as stackable protocol layers with sensible defaults.

The library is designed with multithreading in mind, allowing you to simultaneously sniff, modify, and transmit packets, ideal for network security tools, traffic analysis, and protocol testing.

Features

• Packet Crafting: Build custom network packets by stacking protocol layers
• Packet Decoding: Parse raw network data into structured protocol objects
• Send & Receive: Transmit packets and capture responses with automatic request/reply matching
• Sniffing: Capture live traffic with BPF filter support
• Thread-Safe: Designed for concurrent operations in multithreaded applications
• ARP Utilities: Built-in ARP ping and ARP spoofing helpers

Supported Protocols

Layer 2	Layer 3	Layer 4	Application
Ethernet	IPv4	TCP	DNS
802.1Q (VLAN)	IPv6	UDP	DHCP
SLL (Linux cooked)	ICMP	TCP Options
Null/Loopback	ICMPv6
	IP Options
	IPv6 Extensions
	ICMP Extensions

IPv6 Extension Headers

• Fragmentation Header
• Routing Header
• Segment Routing Header
• Mobile Routing Header

TCP Options

• Maximum Segment Size
• Timestamps
• Window Scale
• MPTCP
• Padding (NOP, EOL)

IP Options

• Traceroute
• Loose/Strict Source Routing (Pointer-based)
• Padding

Project Structure

libcrafter/
├── crafter/
│   ├── Crafter.h          # Main header including all protocols
│   ├── Layer.h/cpp        # Base class for all protocol layers
│   ├── Packet.h/cpp       # Packet container and manipulation
│   ├── Payload.h/cpp      # Raw payload handling
│   ├── Fields/            # Field types (IP addresses, MAC, numerics, etc.)
│   ├── Protocols/         # Protocol implementations (Ethernet, IP, TCP, etc.)
│   ├── Utils/             # Utilities (Sniffer, ARP tools, helpers)
│   └── ProtoSource/       # Protocol definition source files
├── crafter.h              # Public include header
├── configure.ac           # Autoconf configuration
├── Makefile.am            # Automake build rules
└── autogen.sh             # Bootstrap script

Dependencies

• libpcap - Packet capture library
• pthread - POSIX threads
• libresolv - DNS resolver (for DNS protocol support)
• autoconf & libtool - Build system (for compilation from source)

Installing Dependencies

Debian/Ubuntu:

sudo apt-get install libpcap libpcap-dev autoconf libtool

Fedora/RHEL:

sudo dnf install libpcap libpcap-devel autoconf libtool

macOS (Homebrew):

brew install libpcap autoconf libtool

Building from Source

# Clone the repository
git clone https://github.com/pellegre/libcrafter
cd libcrafter/libcrafter

# Generate build system and compile
./autogen.sh
make

# Install system-wide (requires root)
sudo make install
sudo ldconfig

Build Options

You can specify a custom libpcap location:

./configure --with-libpcap=/path/to/libpcap

Quick Start

Include the Library

#include <crafter.h>
using namespace Crafter;

Initialize/Cleanup

int main() {
    InitCrafter();
    
    // Your code here
    
    CleanCrafter();
    return 0;
}

Craft a TCP SYN Packet

// Create layers
Ethernet ether;
ether.SetSourceMAC("aa:bb:cc:dd:ee:ff");
ether.SetDestinationMAC("11:22:33:44:55:66");

IP ip;
ip.SetSourceIP("192.168.1.100");
ip.SetDestinationIP("192.168.1.1");

TCP tcp;
tcp.SetSrcPort(12345);
tcp.SetDstPort(80);
tcp.SetFlags(TCP::SYN);

// Stack layers into a packet
Packet packet = ether / ip / tcp;

// Send the packet
packet.Send("eth0");

Sniff Packets

void PacketHandler(Packet* packet, void* user) {
    packet->Print();
}

Sniffer sniff("tcp port 80", "eth0", PacketHandler);
sniff.Capture(10);  // Capture 10 packets

Decode Raw Data

byte raw_data[] = { /* raw packet bytes */ };
Packet packet;
packet.PacketFromEthernet(raw_data, sizeof(raw_data));
packet.Print();

Compilation

Link against libcrafter when compiling your programs:

g++ -o prog prog.cpp -lcrafter -lpcap -lpthread

Or use pkg-config:

g++ -o prog prog.cpp $(pkg-config --cflags --libs crafter)

Examples

More examples are available at: https://github.com/pellegre/libcrafter-examples

License

This project is licensed under the BSD 3-Clause License. See the LICENSE file for details.

Author

Esteban Pellegrino