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So you're interested in hacking on NetworkManager? Here's some cool stuff you could do... * Use netlink API instead of ioctl based ethtool. NetworkManager uses ethtool API to set/obtain certain settings of network devices. This is an ioctl based API and implmented in "src/platform/nm-platform-utils.c". Recently, kernel got a netlink API for the same functionality (https://www.kernel.org/doc/html/latest/networking/ethtool-netlink.html). NetworkManager should use this API if present, and fallback to the old API when running on older kernels. The benefit if this is that netlink provides notifications when settings change. The ethtool command line tool also implements this API, however it is under an incompatible license, so better don't look and make sure not to use the code. * Add 802-1x capability to nmtui. Add dialogs to nmtui for 802-1x. This will be useful for ethernet (with 802-1x port authentication), enterprise Wi-Fi and MACSec. From the GUI and dialog design, possibly get inspired by nm-connection-editor. * Add Azure support to nm-cloud-setup. Currently, nm-cloud-setup only works for EC2 (and only for IPv4). Add support for Azure cloud. See for example SUSE's cloud-netconfig which supports Azure (https://github.com/SUSE-Enceladus/cloud-netconfig, https://www.suse.com/c/multi-nic-cloud-netconfig-ec2-azure/). Note that cloud-netconfig is under an incompatible license, so be careful not to reuse any code. But that would anyway be almost impossible, because one is written in bash and the other in C. * Improve our gitlab-ci integration. Currently, our .gitlab-ci starts various base containers and first installs the necessary dependencies. That takes time and consumes bandwidth, we should instead use more suitable containers. We should instead use ci-templates from https://gitlab.freedesktop.org/freedesktop/ci-templates. * Ethernet Network Auto-detection There are various methods we can use to autodetect which wired network connection to use if the user connects to more than one wired network on a frequent basis. First, 802.1x enterprise switches broadcast frames which can be used to indicate that the switch supports 802.1x and thus allow NetworkManager to select an 802.1x connection instead of blindly trying DHCP. Second, NetworkManager could listen for traffic from a list of MAC addresses. Third, NetworkManager could integrate 'arping' functionality to determine if a given IP address matches a given MAC address, and thus automatically select that connection. All these methods can co-exist and be used in parallel. One small caveat is that MAC addresses are trivial to spoof, so just because NetworkManager has discovered a certain MAC address does not mean the network is authenticated; only 802.1x security can assure that a network is the network the user expects it to be. In any case, a new 'anchor-addresses' property of type string-array should be added to the NMSettingWired setting. Each string element of this property should be of the format "<ip>/<mac>" or simply "<mac>". The first format with an IP address would indicate that "arping"-type behavior should be used to actively detect the given MAC address; obviously if the given MAC address is used for passive discovery as well. The second format simply lists a MAC address to passively listen for. One drawback of listening or probing for known MAC addresses is an increase in latency during connections to ethernet networks. The probing/listening delay should be a reasonable amount of time, like 4 - 5 seconds or so, and should only be used when a visible connection has anchor addresses. Next a gboolean 'anchor-probing' variable should be added to the NMDeviceEthernetPrivate structure in src/nm-device-ethernet.c. This variable should be set to TRUE whenever the device's carrier turns on *and* there are visible NMConnections with anchor addresses (ie, connections which are system- wide or where one of the allowed users of that connection is logged in). Then probing and listening are started, which involves opening a low-level socket on the interface and starting the arping run or listening for MAC addresses. A timer is also started (don't forget to cache the timer's source ID in the NMDeviceEthernetPrivate data, and to cancel the timer whenever the device transitions to any state other than DISCONNECTED). If a known MAC address is discovered as a result of probing or listening, the probe/listen socket, timeout, and data are cleaned up, and NetworkManager would begin activation of the NMConnection that specified the found MAC address in the 'anchor-addresses' property. If two or more connections specify the same MAC address, the connection with the most recent timestamp should be preferred. Similarly, if the probing/listening process detects 802.1x frames the device should be marked as requiring 802.1x authentication until the carrier drops. This would be accomplished by adding a new property to the NMDeviceEthernet object and exporting that property through the introspection/nm-device-ethernet.xml file. This would allow clients like applets to ensure that users are aware that the device will not allow un-authenticated connections and that additional credentials are required to successfully connect to this network. * VPN re-connect (bgo #349151) NM should remember whether a VPN was connected if a connection disconnects (like Wi-Fi drops out or short carrier drop) or if the laptop goes to sleep. Upon reconnect, if the same Connection is again active, the previously connected VPN should be activated again as well. Basically, don't just drop the VPN because Wi-Fi choked for 10 seconds, but reconnect the VPN if it was connected before the drop. * VPN IP Methods Some VPNs (openvpn with TAP for example) require that DHCP is run on a pseudo-ethernet device to obtain addressing information. Currenty, this is not possible, but NM already has all the code for DHCP. Thus, a new "method" key should be defined in include/NetworkManagerVPN.h to allow for DHCP to be performed if the VPN service daemon requests it in the IP4Config or IP6Config signals. In nm-vpn-connection.c, upon receipt of the D-Bus Ip4Config signal from the VPN plugin, NetworkManager would inspect the "method" property of the ip4 config dictionary. If that property was present and set to "auto" then DHCP would be started using the network interface returned in the dict. The nm_vpn_connection_ip4_config_get() function should be split up into two functions, one containing the existing code for static configuration, and a second for handling DHCP kickoff. Minimal parsing of the response should be handled in the newly reduced nm_vpn_connection_ip4_config_get() function. To handle DHCP, the NMVPNConnectionPrivate structure should have two members added: NMDHCPManager *dhcp_manager; NMDHCPClient *dhcp4_client; which would be initialized in the new DHCP handler code split off from nm_vpn_connection_ip4_config_get(). These new members would be disposed of in both vpn_cleanup() and dispose(), though remember to stop any ongoing DHCP transaction when doing so (see dhcp4_cleanup() in nm-device.c for example code). For basic code to start the DHCP transaction, see dhcp4_start() in nm-device.c as well. After calling nm_dhcp_manager_start_ip4() and connecting the signals to monitor success and failure, the VPN IP4 config handler would simply return without changing VPN state, unless a failure occurred. Then, when the DHCP transaction succeeds, which we'd know by checking the DHCP client state changes in the "state-changed" signal handler we attached to the DHCP client object returned from nm_dhcp_manager_start_ip4(), the code would retrieve the completed NMIP4Config object from the DHCP client using the nm_dhcp_client_get_ip4_config() function, and then proceed to execute essentially the bottom-half of the existing nm_vpn_connection_ip4_config_get() function to merge that config with user overrides and apply it to the VPN tunnel interface. Other state changes from the DHCP client might trigger a failure of the VPN connection, just like DHCP timeouts and lease-renewal failures do for other devices (see dhcp_state_changed() in nm-device.c). * VPN Service Daemon Secret Requests In addition to NM asking the service daemons whether more secrets are required, VPN service daemons (like nm-vpnc-service, nm-openvpn-service, etc) should be able to ask NetworkManager to provide secrets during the connection attempt. To do this, the plugin should advertise its ability to handle out-of-band secrets in its .service file via the key 'async-secrets=true'. NetworkManager would check that key and if present activate the VPN as normal, but skip the explicit NeedSecrets calls. Instead, a new "SecretsRequired" signal would be added to introspection/nm-vpn-plugin.xml (and corresponding helper code added to libnm-glib/nm-vpn-plugin.c) that would be emitted when the plugin determined that secrets were required. This signal would have D-Bus signature of "sas" for the arguments [ <s:uuid>, <as:secrets> ] with the <uuid> obviously being the connection UUID, and <secrets> being an array of strings of plugin-specific strings the plugin requires secrets for. This array of strings would then be passed as the "hints" parameter in nm-vpn-connection.c when secrets are requested from agents in a subsequent nm_settings_connection_get_secrets() call. At this time the agent code only allows one hint per request, so we may need to extend that to allow more than one hint. Thus when connecting if the plugin supported async secrets NetworkManager would still request existing secrets (without interactivity) and send them to the VPN service daemon in the Connect D-Bus method, then wait for the service daemon to either request secrets asynchronously via the SecretsRequired signal or to signal successful connection via the Ip4Config signal. The vpnc plugin would need to be reworked to open a pipe to vpnc's stdout and stdin file descriptors to capture any authentication messages, and to match these messages to known secrets request strings. When receiving one of these strings the plugin would determine which secret was being requested and then emit the SecretsRequired signal to NetworkManager. This would also imply that nm-vpnc-service exectutes vpnc with the "--xauth-inter" argument to enable challenge-response and does not use the "--non-inter" flag which suppresses that behavior. * WPS wpa_supplicant has support for WPS (Wifi Protected Setup, basically Bluetooth- like PIN codes for setting up a wifi connection) and we should add support for this to NetworkManager too. APs that support WPS will say so in their beacon IEs which are contained in the "WPA" and "RSN" properties of the BSS object exported by the supplicant, and can be processed in src/nm-wifi-ap.c's foreach_property_cb() function. We should add some private fields to the NMAccessPoint object (defined in nm-wifi-ap.c) to remember whether a specific AP supports WPS and what WPS methods it supports, and expose that over D-Bus to GUI clients as well. There are two common WPS setup methods: PIN and button. For PIN, the router either displays a random PIN on an LCD or the router's web UI, or a static PIN is printed on the router itself. The user enters that PIN instead of a PSK when connecting. For the "button" method, the router has a physical button that when pushed, allows any client to connect for a short period of time. We'll then need to add some properties to the NMSettingWirelessSecurity setting for the WPS PIN code so that when the user enters it through the GUI, it can be passed back to NM. And we'll need to figure out some mechanism for passing back an indication that the user pushed the button on the router for the pushbutton method. When connecting to a new access point that supports WPS, the GUI client would call the AddAndActivateConnection method and wait for NM to request secrets. NM would determine that the AP supports WPS, and request WPS secrets from the applet. The applet would ask the user for a PIN, or to push the button on the AP, instead of asking for a passphrase or PSK. When the user has entered the PIN or pushed the button, the applet returns this information to NM, which proceeds with the connection. NM sends the correct wpa_supplicant config for WPS to the supplicant, and waits for the connection to occur. WPS can only be used the *first* time, so after a first successful connection, NM must request the actual hexadecimal PSK from wpa_supplicant via D-Bus, and store that PSK in the connection, clear any WPS PIN code from the connection, and save the connection to backing storage. Any applet GUI should also allow the user to enter the PSK instead of completing association using WPS, since quite a few routers out there are broken, or because the user has no physical access to the router itself, but has been given as passphrase/PSK instead. * Better Tablet/Mobile Behavior There are a few components to this: 1) kernel driver and hardware capabilities: most mobile devices use periodic background scanning to quickly determine whether a known SSID is available and notify the connection manager to connect to it. This typically requires special capabilities and good powersave/sleep support from the Wi-Fi kernel driver. There is a background scanning API in nl80211, but we need to determine how many SSIDs each driver allows for background scanning, and based on that number, give the driver the most recent N SSIDs. We still need to periodically wake the device up and do a full scan just in case the user is near a known SSID that was not in the N top recently used networks. This is also beneficial to normal desktop use-cases. wpa_supplicant doesn't currently provide an explicit interface for sending SSIDs to the driver for background scanning, but could simply send a list using configured networks. However, NM currently does not send *all* configured connections' SSIDs to the supplicant, so that's something we should do first to optimize connection times. To do this, NM would need to order all networks using the NM timestamp and convert that into a supplicant priority number, which would need to be adjusted periodically when the timestamp was updated. This would involve tracking each network (exposed by the supplicant as a D-Bus object) and making sure they were added, deleted, and updated when the backing NMConnection objects changed. One complication is that the supplicant requires secrets for various network types when the network is added via D-Bus, and NetworkManager might not have those secrets yet. We may need to modify the supplicant allow for *all* secrets (PSKs, WEP keys, etc) to be requested on-demand, not just EAP secrets like 802.1x passwords. We then need to fix up the supplicant's D-Bus interface to actually send requests for secrets out over D-Bus (like wpa_supplicant_eap_param_needed() does for the socket-based control interface) and to handle the resulting reply from a D-Bus client like wpa_supplicant_ctrl_iface_ctrl_rsp() does. With the secrets request stuff and priority handling in place, wpa_supplicant would control network selection and roaming (based on the priorities NM gave it of course) instead of NetworkManager itself, and hopefully lead to a faster WiFi connection process. 2) single-device-at-a-time with overlapping connections: this is also probably the best route to go for desktop use-cases as well. Instead of bringing all available connections up, only bring up the "best" connection at any given time based on the current priority list (which is roughly Ethernet > Wi-Fi > 3G/Bluetooth). However, to ensure seamless connectivity, when one connection begins to degrade, the next-best connection should be started before the current one is terminated, such that there is a small amount of overlap. Consequently the same behavior should be used when a better connection becomes available. This behavior should be suspended when special connections like Internet Connection Sharing ones are started, where clearly the priorities are different (ie, for Mobile Hotspot 3G > WiFi).