netmon Libcrafter is a high level library for C++ designed to facilitate the creation and decoding of network packets. It is able to craft or decode packets of most common networks protocols, send them on the wire, capture them and match requests and replies. It enables the creation of networking tools in a few lines with a interface very similar to net-analyzer/scapy. A packet is described as layers that you stack one upon the other. Fields of each layer have useful default values that you can overload. The library is designed to be used in multithreaded programs where you can combine several tasks simultaneously. For example, you can easily design something that sniffs, mangles, and sends at the same time you are doing an ARP-Spoofing attack. It also contains a very naive implementation of the TCP/IP stack (fragmentation is no handled yet) at user level that enables working with TCP streams. This facilitates the creation of tools for data injection on arbitrary connections, IP spoofing and TCP/IP session hijacking. Supported protocols are: Ethernet, SLL (Linux cooked-mode capture), ARP, DHCP, DHCP options, IP, IP options, IPv6, ICMP, ICMPv6, ICMP extensions, ICMPv6 extensions, TCP, TCP options, UDP and DNS