User documentation ‹ 1. Learning with cloonix › 15. Wifi: from the radio to the ip stack
Cloonix is a set of C daemons and a python client; the work of emulating a machine, switching a frame, running a container, reaching the internet or decoding a packet is done by projects it recompiles into /usr/libexec/cloonix/cloonfs. This chapter says where each one comes from and who wrote it, as the demos chapter does for the software the demos run.
QEMU was written by Fabrice Bellard and released in 2003, a machine emulator that translates the guest's instructions into the host's as it runs; Bellard is also the author of FFmpeg and of the Tiny C Compiler. KVM was written by Avi Kivity at Qumranet in Israel in 2006 and merged in linux 2.6.20 in February 2007: the kernel exposes the virtualisation extensions of the processor as /dev/kvm and qemu uses them to run the guest's code without translating it. The virtio devices a cloonix guest sees, its disc and its network interfaces, were designed by Rusty Russell in 2007 as one device model for every hypervisor; vtnet0 of the freebsd guest is the same device. The qcow2 disc format of bulk is qemu's own, from 2006. QEMU is the work of a community led since Bellard by Anthony Liguori, then Peter Maydell and Paolo Bonzini.
Open vSwitch was started in 2009 at Nicira Networks by Martin Casado, Ben Pfaff and Justin Pettit, after Casado's doctoral work at Stanford on OpenFlow, a switch whose forwarding table is programmed from outside. Its kernel datapath was merged in linux 3.3 in 2012, Nicira became part of VMware the same year, and the project has been hosted by the Linux Foundation since 2016. A cloonix lan is one of its bridges; the cloonix-ovs-vswitchd of the private namespace is its vswitchd, and dump ovs-vsctl reads it as the ovs chapter shows.
A container is a process with its own view of the kernel: namespaces, written into linux from 2002 by Eric Biederman among others, and cgroups, by Paul Menage and Rohit Seth at Google in 2007. Docker, released by Solomon Hykes in 2013, made the assembly usable and its runtime became runc, the reference implementation of the Open Container Initiative founded in 2015. crun was written by Giuseppe Scrivano at Red Hat in 2017 as an implementation of the same specification in C, one small binary where runc is a Go program. Cloonix creates every cnt with it, and way 2 of the install runs cloonix itself inside a crun container.
User-mode networking, a tcp/ip stack in a process that needs no privilege, was written by Danny Gasparovski in 1995 as SLiRP, so that a dial-up shell account could carry a ppp link; qemu adopted it in 2004 as its default network. passt was written by Stefano Brivio at Red Hat in 2021 to replace it: it moves the bytes of each connection between the guest's sockets and sockets of its own on the host, forwards nothing at the ip layer, and holds no privilege. The cloonix nat is one passt per nat item.
Capturing on an interface is libpcap, written in 1988 at Lawrence Berkeley Laboratory by Van Jacobson, Craig Leres and Steven McCanne together with tcpdump; the capture filter of sniff, udp port 53, is the BPF language of McCanne and Jacobson from 1992, compiled and run where the packets are. Decoding them is Wireshark, begun by Gerald Combs in 1998 under the name Ethereal and renamed in 2006 when Combs changed employer and the old name stayed behind. Cloonix compiles its dissectors without the Qt interface; webshark and the PcapRec item read the result in the browser.
Both ports of a net are tls. The library is OpenSSL, which began in 1995 as SSLeay by Eric A. Young and Tim Hudson in Australia, became OpenSSL in December 1998, and has been run by the OpenSSL Software Foundation since the Heartbleed bug of 2014 brought it funding and full-time developers. TLS itself is the IETF's 1999 rewrite of Netscape's SSL of 1994.
The console of a kvm, and the way cisco.py drives a guest that has no agent, go through dtach, written by Ned T. Crigler in 2004: the detach and reattach of GNU screen, a few hundred lines, and nothing else. GNU screen itself dates from 1987, by Oliver Laumann.
patchelf was written by Eelco Dolstra in 2004 for the Nix package manager, whose packages each carry their own dependencies and therefore need the interpreter and the rpath of every binary rewritten. Cloonix uses it at packing time for the same reason, so that nothing in cloonfs opens a library of the host.
VNC and its RFB protocol were written at the Olivetti Research Laboratory in Cambridge by Tristan Richardson and Quentin Stafford-Fraser and released in 1998; noVNC, by Joel Martin in 2010, speaks RFB from a browser over a websocket and is the desktop of a kvm in the web GUI. xterm.js, begun in 2016 at SourceLair from the term.js of Christopher Jeffrey, is the terminal of the shell panels; the same component is the terminal of Visual Studio Code.
The container and kvm images of bulk are Debian, the distribution founded by Ian Murdock in August 1993 and run since by its developers under a social contract of 1997; trixie is its release 13. The base root file-system is assembled by mmdebstrap, written by Johannes Schauer Marin Rodrigues in 2018 to build a Debian tree without root.
User documentation ‹ 1. Learning with cloonix › 15. Wifi: from the radio to the ip stack