Recognise Open vSwitch as a bridge

[0n-s]

Bug description

Bridges made with Open vSwitch are not recognised as bridges in transmitted LLDPDUs.

Steps to reproduce the problem

1. Create a bridge with Open vSwitch.
2. Run lldpd on said bridge.

Expected outcome

lldpd should indicate that the interface is a bridge.

Current outcome

[lldpcli] # show interfaces
-------------------------------------------------------------------------------
LLDP interfaces:
-------------------------------------------------------------------------------
Interface:    br0
  Administrative status: RX and TX
  Chassis:
    ChassisID:    mac X
    SysName:      badam
    SysDescr:     Gentoo Linux
    MgmtIP:       X
    MgmtIface:    8
    MgmtIP:       X
    MgmtIface:    8
    Capability:   Bridge, off
    Capability:   Router, on
    Capability:   Wlan, off
    Capability:   Station, off
  Port:
    PortID:       mac X
    PortDescr:    br0
  TTL:          128
-------------------------------------------------------------------------------

[vincentbernat]

What's the output of ip -d l l dev br0?

[0n-s]

7: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1024
    link/ether [redacted] brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 65535
    openvswitch addrgenmode stable_secret numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 gro_max_size 65536

[vincentbernat]

Does the bridge link works? It should display the links attached to br0.

[0n-s]

No (empty output). Open vSwitch isn't a Linux bridge (bridge.ko), mostly works in userspace, & has an entirely different API than Linux bridges in terms of configuration (uses its own toolset & not iproute2). The one piece of Open vSwitch that is often* integrated into the OS is the datapath (hence br0 having type openvswitch).

* For the scope of this bug I'm not considering the userspace-only mode of Open vSwitch that is implemented with TAP devices, & hence probably much harder to properly detect

[vincentbernat]

I remember that OpenvSwitch has a forked version of lldpd builtin. Is there a specific reason you do not rely on it?

[0n-s]

AFAIK this is not a full implementation of LLDP & is merely focused on providing enough support for it to work with SPBM networks.

C.f. https://www.openvswitch.org/support/dist-docs-2.5/ovs-vswitchd.conf.db.5.html (section "AutoAttach TABLE").