Gluon 2018.1

Important notes

This version changes the flash partition layout on some devices (TP-Link CPE/WBS 210/510). To avoid upgrade failures, make sure to upgrade to Gluon 2017.1.8 or the latest Gluon 2016.2.x (unreleased) before installing Gluon 2018.1.

Some of the following paragraphs describe so-called “feature flags”. This new concept is explained in Feature flags.

Added hardware support

ar71xx-generic

  • ALFA NETWORK
    • AP121F
  • AVM
    • FRITZ!Box 4020
  • OpenMesh
    • A40
    • A60
    • OM2P v4
    • OM2P-HS v4
  • TP-Link
    • Archer C59 v1 [2]
    • CPE210 v2

ar71xx-nand

  • ZyXEL
    • NBG6716

ar71xx-tiny

  • TP-Link
    • TL-WA901ND v5

ipq806x [1] [2]

  • TP-Link
    • Archer C2600

ramips-mt7620 [1] [2]

  • GL Innovations
    • GL-MT300A
    • GL-MT300N
    • GL-MT750

ramips-mt7628 [1] [2]

  • VoCore
    • VoCore 2

ramips-rt305x [1] [2]

  • A5
    • V11
  • D-Link
    • DIR615 (D1, D2, D3, D4, H1)
  • VoCore
    • VoCore (8MB, 16MB)

sunxi [1]

  • LeMaker/SinoVoip
    • Banana Pi (M1)
[1](1, 2, 3, 4, 5) New target
[2](1, 2, 3, 4, 5) Device or target does not support AP+IBSS mode: This device or target will not be built when GLUON_WLAN_MESH is set to ibss.

New features

Multidomain support

When mesh networks grow too large, it becomes necessary to split them into multiple independent mesh domains to allow the meshes to work with reasonable performance. Formerly, the only way to achieve this with Gluon was to build a separate set of firmware images for each domain.

With Gluon 2018.1, multidomain firmwares can be used to achieve the same, using only a single site configuration that is basis for several different domain-specific configurations. The feature is explained in detail in Multidomain Support.

Wired mesh encapsulation

Gluon now supports encapsulating wired mesh traffic (Mesh on LAN/WAN) in VXLAN. See Wired mesh (Mesh-on-WAN/LAN) for details on this feature.

Router advertisement filtering

Similar to the builtin batman-adv gateway feature for IPv4, the gluon-radv-filterd package (radv-filterd feature flag) allows to filter IPv6 router advertisements received from the mesh so that only the RAs with the best routing metric (TQ) reach the clients, ensuring that the “best” (topologically closest) gateway is chosen as the IPv6 default route, thereby reducing gateway crosstalk.

At the moment, this feature only filters RAs forwarded to clients; the RAs handled on the nodes themselves will be unfiltered, so the nodes will still use arbitrary default gateways.

IGMP/MLD segmentation

The IGMP/MLD segmentation feature previously provided by the gluon-ebtables-segment-mld package has been extended and moved into the Gluon core; it does not exist as a separate package anymore.

Filtering IGMP/MLD queries directed towards the mesh ensures that each node becomes the multicast querier for its own clients (unless there are other multicast-aware switches connected to the node), rather than electing a single, basically arbitrary node in the mesh to become the querier. Overall, this should significantly improve the reliablity of multicast in the mesh. This is especially important for IPv6, as the IPv6 Neighbour Discovery Protocol (NDP) is based on local multicast.

See also the documentation of the site.conf mesh section.

gluon-ebtables-limit-arp

The gluon-ebtables-limit-arp (ebtables-limit-arp feature flag) package adds filters to limit the rate of ARP requests client devices are allowed to send into the mesh.

Certain client applications are known to generate a significant amount of such ARP requests and are reportedly becoming more and more common. Without this package, such clients are one known cause for mesh wide load and congestion problems (see also the Known issues section below).

Because of this package’s implementation, which relies on frequent dynamic updates - something ebtables does not perform well at - it is not included by default, as it can cause unnecessary load. Feedback, especially with a close look on load and congestion on nodes with a large number of changing client devices, is very much welcome. Depending on the feedback, we might enable this feature by default in a future release.

Public key in respondd data (optional)

If desired, the fastd public key of a node can be included in the respondd nodeinfo data, faciliating the correlations of VPN peers and nodes. As the VPN key is transmitted unencrypted in the fastd handshake, this would theoretically allow an ISP to determine which nodes are operated behind which internet line. Therefore, this feature must be enabled explicitly by setting mesh_vpn.pubkey_privacy to false in site.conf.

B.A.T.M.A.N. V (experimental)

When using batman-adv compat 15, it is now possible to switch to the new routing algorithm B.A.T.M.A.N. V (while the old algorithm is called B.A.T.M.A.N. IV) by setting mesh.batman_adv.routing_algo to "BATMAN_V". Note that the new routing algorithm is not backwards-compatible, so nodes using different algorithms can not interoperate.

Site changes

site.mk

  • Due to improved package dependency handling, the packages gluon-config-mode-core and gluon-setup-mode do not need to be listed explicitly in site.mk anymore; they will be pulled in implicitly.
  • Including the ebtables-limit-arp feature flag is recommended. Please note the abovementioned caveats on this feature.
  • We recommend to use GLUON_FEATURES for all Gluon packages, and rely on GLUON_SITE_PACKAGES for non-Gluon (OpenWrt) packages only, as explained in Feature flags.

site.conf

When updating a site configuration from Gluon 2017.1.x, the following changes must be made:

  • domain_seed = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
    

    These 32 bytes of random data (encoded in hexadecimal) are used to seed a number of site/domain specific random values that must be the same on all nodes of the same mesh, but different for different meshes. The following command can be used to generate such a random value:

    echo $(hexdump -v -n 32 -e '1/1 "%02x"' </dev/urandom)
    

    In multidomain setups, repeat this command for each domain.

    At this time, only the VXLAN ID for wired meshing is derived from the domain seed.

  • mesh = {
      vxlan = true, -- or false
      -- ...
    },
    

    In single domain setups, the new mesh.vxlan option is mandatory. It should be set to true in new meshes; existing setups should set it to false to retain compatibility with older versions of Gluon.

    In multidomain setups, mesh.vxlan defaults to true and does not need to be set explicitly. It can still be set to false for individual domains that should allow wired meshing with existing setups, which is also useful for migrating an existing mesh to a multidomain-capable firmware.

  • Password change form

    The password change form in the “Advanced settings” is not shown by default anymore, as SSH keys are the recommended means of authentication. It is still possible to set a password via SSH while in config mode.

    Set

    config_mode = {
      remote_login = {
        show_password_form = true,
        -- ...
      },
      -- ...
    },
    

    to restore the old behaviour.

    When shown, the password form requires a minimum password length of 12 characters now. This requirement can be modified using the config_mode.remote_login.min_password_length setting.

  • Next-node hostnames

    The builtin DNS resolver of Gluon can be configured to resolve a next-node hostname to the next-node IP address without querying an upstream DNS server. Since Gluon v2018.1, multiple names can be specified. Old configurations setting next_node.name to a string must be updated to provide an array of strings instead:

    next_node = {
      name = { 'nextnode.location.community.example.org' },
      -- ...
    },
    

i18n

It is now possible to override a few labels and descriptions in the configuration wizard. The available message IDs are listed in Config mode texts.

These new i18n strings are optional; leaving them empty or unset will retain the default texts.

Internals

Status page rewrite

The status page has been rewritten to simplify the code and reduce its size. Rather than having a static frontend and retrieving all information via JavaScript, all static information in the status page is now generated on the node, and JavaScript is only used for dynamic data.

Many status page API endpoints have been removed; for all remaining endpoints, CORS (Cross-Origin Resource Sharing) has been disabled, as it led to a privacy issues: malicious websites could access the API via cross-site scripting, determining which node a user was connected to.

The removal of CORS breaks compatibility with the node switching feature of the old status page implementation: In the new status page, switching to another node will reload the whole status page from the target node, while the old implementation would only switch to another backend host. While this will facilitate future updates, as frontend and backend always come from the same node and no stable API needs to be maintained, it prevents switching from the old status page to nodes running the new version.

To achieve all this, the status page was ported to the gluon-web framework. The new status page also makes use of Gluon’s usual i18n facilities now. In addition, the gluon-web-model package was split out of the gluon-web core package, as model support is only required for config mode packages, but not for the new status page.

i18n namespaces

In earlier version of Gluon, all gluon-web (formerly LuCI) packages shared the same i18n namespace, so independent packages could override each others translations (with an arbitrary translation of the same string “winning”). This issue has been solved by giving each package its own translation namespace, which is defined by the package directive in a package’s controller. It is still possible to access a different i18n namespace (e.g. gluon-web base or site translations), which is described in Internationalization support.

Package Makefile cleanup

The Makefiles of the individual Gluon packages have been cleaned up significantly by moving a lot of boilerplate code to package/gluon.mk. The new features of package/gluon.mk are explained in detail in Package development.

Site checker

  • New JSON/Lua path specification

    The old string-based path specifications in site check scripts (e.g. 'autoupdater.branch') have been replaced with arrays ({'autoupdater', 'branch'}). This will implicitly ensure that autoupdater is a table when it exists (simplifying checks for deep structures), and it makes it easier to specify paths with variable components (by referencing a variable as an array element).

  • Alternatives

    The site check library has gained support for alternatives. It is now possible to check if a configuration satisfies one of multiple checks:

    -- foo can be a boolean or a string!
    alternatives(function()
      need_boolean({'foo'})
    end, function()
      need_string({'foo'})
    end)
    

    As many branches (functions) as necessary can be passed to a single alternatives call, which will succeed when at least one of the branches succeeds.

batman-adv multicast optimizations

After various extra rounds of testing and fixes, the batman-adv (compat 15) multicast optimizations were reenabled: knowledge about potential multicast listeners is gathered and distributed through the mesh again.

This is the next step towards the addition of the actual multicast distribution optimizations, which are being prepared in #1357. When finished, the optimizations will help reduce the remaining Layer-2-specific network overhead, e.g. multicasted ICMPv6 messages.

No behaviour changes are expected yet, as the multicast sender side is still disabled. Once the majority of the mesh network has been updated to Gluon 2018.1, it can be activated on dedicated nodes by including #1357 in the firmware build. Test feedback is very welcome.

Known issues

  • Default TX power on many Ubiquiti devices is too high, correct offsets are unknown (#94)

    Reducing the TX power in the Advanced Settings is recommended.

  • The MAC address of the WAN interface is modified even when Mesh-on-WAN is disabled (#496)

    This may lead to issues in environments where a fixed MAC address is expected (like VMware when promicious mode is disallowed).

  • Inconsistent respondd API (#522)

    The current API is inconsistent and will be replaced eventually. The old API will still be supported for a while.

  • Frequent reboots due to out-of-memory or high load due to memory pressure on weak hardware specially in larger meshes (#1243)

    Optimizations in Gluon 2018.1 have significantly improved memory usage. There are still known bugs leading to unreasonably high load that we hope to solve in future releases.

  • Configuration loss on upgrade under certain circumstances (#1496)

    The issue can only occur when upgrading from 2018.1 and there are multiple mirror entries in site.conf (specifically, an early failure for one of the mirrors, e.g. during DNS resolution, followed by a successful upgrade from a different mirror triggers the issue).

    This is a regression in Gluon 2018.1.

  • Next-node ARP issue (#1488)

    A routing table issue leads to ARP requests being sent from the next-node IPv4 address, but with a node-specific source MAC address. This can make the next-node IPv4 address unreachable.

    This is a regression in Gluon 2018.1.