6. The core binaries

6.1. cloonix-main-server

Source: cloonsrc/uml_cloonix_switch, a Makefile, about sixty files. The only process holding the topology; no two helpers talk to each other directly. At start, in the order of uml_clownix_switch.c: read cloonix.cfg for the net named on the command line, check the work directory, refuse if another instance holds the lock, create the proxyshare directory, fork the helpers.

recv_from_client.c    every command a client can send, in one switch
cfg_store.c           the topology, the only place it is stored
machine_create.c      adding a kvm or a cnt, end to end
suid_power.c          the client half of the privileged channel
ovs.c ovs_snf.c ...   one file per helper it manages: ovs_a2b, ovs_c2c, ovs_nat_main, ovs_tap
automates.c           the state machines that survive a helper dying
qcow2_hdr.c           the qcow2 overlay of a kvm, header only, no qemu-img
pcap_filter.c         the capture filter grammar
list_commands.c       dump commands, the lines that replay the net
targz.c               a cnt image given as bulk/<n>.tar.gz: extracted once into
                      bulk/<n>_targz by a clone, the add parked until it is there;
                      the tree keeps the modes of the archive, its protection is
                      idmap_mount_ro of suid_power, the read only lower of the overlay

Every helper is started the same way, ovs.c at connect_ovs_try being the model: write the socket path, fork the helper with it in argv, retry connecting on a timer until it answers or a count runs out.

6.2. cloonix-doorways

Source: cloonsrc/doorways, a Makefile, about 2200 lines. Binds no tcp port: it listens on proxy_pmain.sock, where proxymous delivers what arrived on cloonix_port, checks the hmac, and relays between that client and the unix socket of the main server, so the process holding the topology never listens on tcp. dispach.c routes the leg types; llid_traffic.c holds the data path and check_wire_version.

6.3. cloonix-cxp-cli

Source: cloonsrc/cxp_cli, one file of about 650 lines:

cloonix-cxp-cli <ip:port | unix_socket> <passwd> <vm> [command...]

A shell in a guest or one command in it, over a doors_type_dbssh leg, the C end of the cxp protocol of cxp_wire.h; no key exchange, no host key, nothing of ssh but the ssh verb of the client. An ip:port target is wrapped in tls, unverified, and spoken to in clear with a warning when it does not answer the hello, unless CLOONIX_REQUIRE_TLS=1 is set. A <passwd> of - is read from CLOONIX_PASSWD, which is how web_pty.c of the gui server runs it under forkpty, and how the sh script that is cloonix inside the toy's container calls it; there is no C command line, the vocabulary lives in cloonix/cloonix alone, and a new verb is one entry of its to_json() plus the message in json_interface.c.

6.4. cloonix-proxymous

Source: cloonsrc/proxymous_passt, a Makefile, about 6400 lines. The one process that stays on the host in the toy, hence its four jobs:

• The web door. jsweb_relay.c, proxy_tls.c: accepts https on every address, terminates TLS, splices the plaintext to proxy_pjsweb.sock. The same proxy_tls.c ends the tls of the doors port in set_config.c, where the first byte of a connection tells a client hello from a plain frame. OpenSSL never sees a descriptor: the bytes go through a pair of memory BIOs, and after every operation the write BIO is emptied towards the peer.

  

• passt. passt_spawn.c starts one cloonix-passt per nat, on the host, with the -t and -u of the published ports. The binary is taken beside proxymous, pthexec_self_bin_dir(): cloonfs/bin in the bundle, bin/ of the toy, which carries it for that.

• Demos. demo_exec.c runs the text the gui server read from its own disk.

• The udp relay of the c2c. udp_proxy.c: one relay per c2c keyed by its name, five at most (MAX_UDP_PROXY), binding the first free port at or above c2c_udp_port_low over a hundred and sending it back to the switch; the unix sockets carry the port, dgram_c2c_<port>_tx.sock and _rx.sock. A sixth c2c is refused naming the five.