FreeBSD Wireless bridge + bhyve + Alpine Linux.

Brief

I always liked FreeBSD because its stability, some servers I've launched years ago are still up and working; however I feel like the desktop experience cannot satisfy my requirements to be used as a daily driver.

The main stopper to me, is the low wifi performance with the actual available drivers; I've been twerking lots of kernel options and others configs, but at the end gave up.

In some forum I heard about wifibox, although a workaround already exists, I wanted to research and do it by myself, before give it a try or read about it.

Back in the 2010, I had to virtualize a PBX server with asterisk over Centos using KVM, I remember having to deal with AMD IOMMU and Intel VT-d, for passthrough several E1/T1 pci cards, so that give me an idea about a possible way to overcome the slow wifi speed.

My first step was to find a virtualization technology available for FreeBSD that supported pci passthrough, It wasn't difficult and my first though was Bhyve; I'd already used it in the past but never used these passthrough features.

Actually my approach was kinda simple, virtualize a lightweight linux system with good support for hardware, then create a network bridge between wireless and ethernet interface, so the wireless interface handled the authentication stuff and established the layer 1 link, and then layers 2-3 were shared through bridge. In the host side a tap interface would suffice the network connections needs.

Bhyve Environment

First of all was to setting up bhyve and install required packages.

Installation of required packages.

# as root
pkg install bhyve-firmware vm-bhyve.

Creation and mount of dedicated zfs dataset.

zfs create zroot/vms
zfs mount

Add startup configs for vm-bhyve.

At the end of /etc/rc.conf

...
vm_enable="YES"
vm_dir="zfs:zroot/vms"

vm-bhyve initialization

# as root
vm init

Creation of a switch for bhyve networking, without any Host interface.

# as root
vm switch create private

Tap interface creation.

# as root
ifconfig tap0 create

The following lines ensure tap interface creating at boot: At the end of /etc/rc.conf

..
cloned_interfaces="tap0 up"
ifconfig_tap0="DHCP"

Copy templates.

# as root
mkdir /zroot/vms/.templates
cp /usr/local/share/examples/vm-bhyve/* /zroot/vms/.templates/

Download installation iso, I've used alpine linux standard. I tried with virt edition before but wireless card doesn't get recognized.

# as root
vm iso https://dl-cdn.alpinelinux.org/alpine/v3.20/releases/x86_64/alpine-standard-3.20.3-x86_64.iso

Kernel configs

Identify the wireless card pci id for passthrough, and save the value the next step.

pciconf -l|awk '
($0 ~ "class=0x028000")
{split($0,a, ":");print a[2] "/" a[3] "/" a[4]}
'

Added these lines to /boot/loader.conf

...
hw.vtnet.csum_disable="1"
vmm_load="YES"
nmdm_load="YES"
if_tap_load="YES"
if_brigde_load="YES"
# The following line value is the returned one from the previous command.
pptdevs="3/0/0"
# In my case "3/0/0" is the pci identifier I get for my wireless card.

Creation of installation template for our wifibox. /zroot/vms/.templates/wifibox.conf

guest="linux"
loader="uefi"
cpu=1
memory=256M
network0_type="virtio-net"
network0_switch="private"
network0_device="tap0"
network0_name="eth0"
disk0_type="virtio-blk"
disk0_name="disk0.img"
# the same pci id as the step before, 3/0/0 for my own card.
passthru0="3/0/0"

Reboot the laptop:

# as root
reboot # or whatever you use to reboot

Alpine installation.

Once the laptop starts over, let check passthrough is working before proceed to to installation.

# as root
vm pass|grep -i yes

Output must looks something like this:

ppt0       3/0/0        Yes          Wireless 7265

If so, run the bhyve installation command for the virtual machine.

# as root
vm create -t wifibox wifiman
# Yes I call my virtual machine "wifiman", I'm bad naming things already know it
vm install -f wifiman alpine-standard-3.20.3-x86_64.iso

I'm not gonna go deep down into Alpine installation process, since it's very simple actually. Just to point out, I've configure the wlan0 interface in the during installation process with my SSID, eth0 left unconfigured, added a new user, and use "sys" as a installation method. Once finished just run poweroff

An advice is to set new user and root a simple password, at least while finish the configurations.

Now start and connect to the virtual machine

# as root
vm start wifiman
vm console wifiman

Now in the virtual machine

# as root
# in the alpine virtual machine
apk update
apk add bridge-utils

Add the following network configurations: /etc/network/interfaces of the virtual machine

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet manual
    down brctl delif br0 eth0 || true
    allow-hotplug eth0

auto wlan0
pre-up iw dev wlan0 set 4addr on
    down brctl delif br0 wlan0 || true
    allow-hotplug wlan0
    iface wlan0 inet manual

auto br0
iface br0 inet dhcp # this is optional, can be manual as well
    pre-up echo 1 > /proc/sys/net/ipv4/ip_forward
    pre-up brctl addbr br0 || true
    pre-up brctl addif br0 eth0 || true
    pre-up brctl addif br0 wlan0 || true
    post-down brctl delbr br0
    bridge_ports eth0 wlan0

Then just reboot the virtual machine networking service

service networking restart

Now in the Host run

# as root
dhclient tap0
# or
service netif restart

Speed test

A little speed