How SynCE Tools Cooperate
Synce projects consists of several utilities, tools and applications that allow users to access files on device, synchronize contacts and calendar and few other. There is no "synce" program. Several tools have to work together in order to "synce" to work. This list briefly mentions their responsibilities in the orchestra. (The list is very incomplete.)
synce-usb-rndis-lite - One type of kernel module for WM5 and later.
rndis_host.ko - kernel module that creates network interface to the device. Required for Windows Mobile 5 over USB, not needed otherwise.
cdc_ether.ko - kernel module that creates network interface to the device. Microsoft uses proprietary extension RNDIS, so it needs rndis_host.ko
usbnet.ko - kernel module providing general networking functions for USB gadgets.
synce-usb-rndis-ng - The other type of kernel module for WM5 and later.
synce-odccm - The latest flavour of the *dccm communication daemon, you need one and only one dccm running. Runned by superuser. Device connects to this daemon (to tcp port 5679). The odccm anounces connection and disconnection events. If device requires password, it will broadcast "PasswordFlagsChanged" over D-Bus and clients (e.g. synce-gnome, synce-engine) will provide odccm the password
synce-vdccm - The previous flavour of dccm communication daemon, and required if you want to use kde integration. You cannot sync WM5/6 if you use vdccm instead of odccm. Also: vdccm is a daemon to keep a connection to your WinCE and WM5 device up. It maintains a connection to a device, responding to keepalives and providing other members of the SynCE suite of tools with details of the IP address and providing the ability to autorun scripts upon connection.
synce-gnome - very simple GNOME applet (daemon) that displays bubble when device is connected and disconnected. If device requires password, it will popup dialog and send the password to odccm.
librtfcomp - A support library for syncing.
pywbxml - Python interface to libwbxml
wbxml2 - Some more sync stuff (libwbxml)
synce-libsynce - Support library for almost everything.
synce-librapi2 - Remote function calls to a WM device.
synce-rra - Sync library for pre WM 5 devices.
synce-serial - Connection scripts for pre WM5 devices.
synce-sync-engine - Sync engine for WM5 and later devices, hopefully soon to support pre WM5.
synce-kde - Kde apps and modules, including a panel applet (sorry about the terms, I'm a gnome user), KIO module etc.
Source: [http://sourceforge.net/mailarchive/forum.php?thread_name=1197562236.26413.28.camel%40mark01.mpellis.org.uk&forum_name=synce-devel Mark Ellis on synce-devel list], Jonny Lamb's vdccm-0.10.1 release announcement (where?)
Details
odccm - uses dbus for notifying clients (e.g. synce-engine and synce-gnome) about connections and disconnections, GNet for communicating with PDA and gobject to use oobject-oriented programming (there may be better reason). Network communication is non-blocking, D-Bus requests processing too. Authentization: device may require password in order to communicate with computer, client is expected to query user and provide it to odccm. Authentization state machine is in conn_event_cb(), handles transition depending on success and failures from device. When clients calls odccm_device_provide_password() via D-Bus, odccm obfuscates it and sends the password to device (gnet_conn_write) and request asynchronous read of authentication result, then return without returning result to the D-Bus call. When result arrives, gnet calls conn_event_cb() which is registered to process all (asynchronously) received data. It appears that all received data are related to authentization. All password state related transitions seem to be in conn_event_cb(). If authentization was in state CTRL_STATE_AUTH and received data indicate success, it returns success to the D-Bus call which initiated odccm_device_provide_password().
Plugging a device
- When Windows Mobile device is plugged to USB, Linux (the kernel) reads device's USB descriptors
- Based on these descriptors Linux somehow loads appropriate modules (for WM5: usbnet.ko, cdc_ether.ko, rndis_host.ko)
- kernel module rndis_host creates new network interface to the device
NetworkManager is notified about the new interface
synce-odccm or NetworkManager obtains IPv4 address for the interface
- synce-odccm daemon broadcasts announcement over D-Bus that new device was attached (device may require password)
- synce-gnome or sync-engine receive the event, ask for password and send it over D-Bus to synce-odccm daemon
- synce-gnome or sync-engine display bubble announcing new device