[FreeBSD] USB Ether(ue0) link down/up issue (WireGuard(wg0) ,14.x and later)

 Current status

FreeBSD Version	CPU	Ethernet Interface	enable Wireguard?	reproduce?	Notes
15.0-ALPHA	amd64	ue0	YES	YES[NG]
			NO	NO[OK]
		cdce0	YES	?
			NO	?
		run0(Wi-Fi)	YES	Testing
			NO	?
		em0	YES	NO[OK]
			NO	?
	arm64	ue0	YES	?
			NO	?
		cdce0	YES	?
			NO	?
		run0(Wi-Fi)	YES	?
			NO	?
		Internal IF	YES	?
			NO	?
14.3-RELEASE	amd64	ue0	YES	?
			NO	?
	arm64	ue0	YES	YES[NG]
			NO	NO[OK]
		Internal IF	YES	NO[OK]	Oracle cloud
14.0-RELEASE	amd64	ue0	YES	Not tested
	arm64		YES	YES[NG]
13.5-RELEASE	amd64	ue0	YES	NO[OK]
	arm64		YES	NO[OK]

NOTE1

• Could changing the order of the interfaces shown by ifconfig from wg0 to ue0 solve the problem?
• Result: It won't solve it[NG].

Enviroment

USB Ethernet

• axe0: <ASIX Elec. Corp. AX88772, rev 2.00/0.01, addr 2> on usbus0
  ue0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> metric 0 mtu 1500
          options=80008<VLAN_MTU,LINKSTATE>
• BUFFALO LUA3-U2-ATX
• BUFFALO LUA3-U2-AGT
• run0: <Ralink 802.11 n WLAN, class 0/0, rev 2.00/1.01, addr 2> on usbus7
  run0: MAC/BBP RT3071 (rev 0x021C), RF RT3022 (MIMO 2T2R), address 4c:xx:xx:xx:xx
• BUFFALO WLI-UC-G300HP

amd64 machine

• Lenovo T400s

arm64 machines

• PINE A64
• Raspberry Pi 4
• Raspberry Pi Zero 2W

Example Configuration of Wireguard 

/usr/local/etc/wireguard/wg0.conf

[Interface]

Privatekey =[PrivateKey]

Address = 10.8.229.1/24

table = off

ListenPort = 1129

[Peer]

PublicKey = [PublicKey]

AllowedIPs = 10.8.0.0/16, 192.168.11.0/24, 192.168.3.0/24,0.0.0.0/0

(NOTES: no EndPoint config, just wait a connection mode)

/etc/rc.conf.local

wireguard_enable="YES"

wireguard_interfaces="wg0"

Related articles

FreeBSD Forums:

• Internet connection going up and down constantly
• Charlie Brown reported using the wg0 with ue0
• Interface flapping on ethernet USB adapter
  
• no information about Wireguard, finally use cdce.

FreeBSD Bugzilla

• Bug 252165 - usb network and mii bus media status race condition