7. The switching binaries

7.1. The openvswitch four

cloonsrc/ovs: a cmd, a patched_create and ovs.patch around the vendored openvswitch; the patch lets several instances run side by side under cloonix's names:

cloonix-ovsdb-server  cloonix-ovsdb-tool    the configuration database
cloonix-ovs-vswitchd                        the switch
cloonix-ovs-vsctl                           the client, unchanged but the name

cloonix-ovs-drv is cloonix's own wrapper, one per net: creates the namespace, starts the database and the switch inside it, and runs every change of the switch the main server asks for, as text on a unix socket: lans, ports, mirrors, taps, phy.

7.2. The satellites

All started by suid-power, none setuid:

cloonix-ovs-drv    one per net: the switch itself, above; netns.c, ovs_cmd.c, action.c
cloonix-ovs-snf    one per sniffed interface: pcap_record.c writes, tun_tap.c reads the
                   mirror, inotify_trigger.c wakes webshark without polling
cloonix-ovs-a2b    the impairment: circle.c the delay ring, replace.c loss, sched.c
cloonix-ovs-c2c    a lan carried over udp: udp.c, rxtx.c, packet_arp_mangle.c
cloonix-ovs-nat    the nat item: machine.c per guest, passt_shuttle.c to the host side

The four other than drv share ctrl_link.c of lib_io_clownix: the listening unix socket the main server connects to, the one live connection (a second one replaces the first, the listener is kept), the watchdog and the stop. The main server sends a pid_req about every second (a2b, nat and snf once per second, c2c on every pass of its heartbeat, 0.5 or 1.5 s); the first must arrive within 5 s, then one per 20 s, or the satellite stops itself with one warning line, both deadlines measured on the monotonic clock with the credit of stall_detect.h for the time the satellite itself was not running. The 20 s are the same silence proxymous gives the switch: a main server late by a few seconds is a host held by something else, a broadcast storm in a guest for one, and a satellite stopping on it cuts a link that was sound; a c2c cut that way is rebuilt by its master, minutes later. Every stop, watchdog, closed connection or kil_req, is the same ctrl_link_stop: the paths the satellite registered are unlinked, its tap children killed, exit 0. A path found at start means the previous holder was killed rather than stopped; it is erased with a warning. The nat keeps a second watchdog of the same period on its proxymous leg. The tap child of a2b, c2c and nat shares tap_child_from_parent and tap_child_to_parent of intf_flags.c; only the tap write policy differs and stays in each tun_tap.c.

cloonix-passt is not cloonix's code, cloonsrc/passt a cmd around the vendored passt; it runs on the host, which is why the shuttle exists. The nat item and the nat code inside proxymous are two things: the first serves the guests, the second cloonix's own traffic.