Matthew Starr
e93b5c1c1f
When a modem reported back non-sequential CIDs, MM was using the next larger CID number after the last CID found. In cases where the last CID found was the highest numbered CID allowed and is not a modifiable CID, MM would give up and fail to establish a data connection. The above issue occurs on u-blox TOBY-R200 modems as of firmware 30.33 A02.02. In this firmware version there are two default CIDs programmed into the modem, one at CID 1 and another at CID 31. The CID at 31 is the highest CID number that can be used and cannot be modified. This change makes it so while parsing CIDs for a match, if a jump in CID numbers is detected, so not sequential, the first open CID will be used before using the max CID +1 or replacing the max CID. If an exact match for IP type and APN is found, then that will still be used first.
ModemManager. ModemManager provides a unified high level API for communicating with mobile broadband modems, regardless of the protocol used to communicate with the actual device (Generic AT, vendor-specific AT, QCDM, QMI, MBIM...). Using. ModemManager is a system daemon and is not meant to be used directly from the command line. However, since it provides a DBus API, it is possible to use 'dbus-send' commands or the new 'mmcli' command line interface to control it from the terminal. The devices are queried from udev and automatically updated based on hardware events, although a manual re-scan can also be requested to look for RS232 modems. Implementation. ModemManager is a DBus system bus activated service (meaning it's started automatically when a request arrives). It is written in C, using glib and gio. Several GInterfaces specify different features that the modems support, including the generic MMIfaceModem3gpp and MMIfaceModemCdma which provide basic operations for 3GPP (GSM, UMTS, LTE) or CDMA (CDMA1x, EV-DO) modems. If a given feature is not available in the modem, the specific interface will not be exported in DBus. Plugins. Plugins are loaded on startup, and must implement the MMPlugin interface. It consists of a couple of methods which tell the daemon whether the plugin supports a port and to create custom MMBroadbandModem implementations. It most likely makes sense to derive custom modem implementations from one of the generic classes and just add (or override) operations which are not standard. There are multiple fully working plugins in the plugins/ directory that can be used as an example for writing new plugins. Writing new plugins is highly encouraged! The plugin API is open for changes, so if you're writing a plugin and need to add or change some public method, feel free to suggest it! License. The ModemManager and mmcli binaries are both GPLv2+. The libmm-glib library is LGPLv2+.