Pi3: Sharing WiFi connexion to a bridge (eth + wifi)

start-pi-lab-net.sh

#!/bin/bash

set -e
set -u
set -x

WIFI_INTERFACE=wlan0
VIRT_WIFI_INTERFACE=wlan1
BRIDGE_INTERFACE=br0
ETH_INTERFACE=eth0
IP_NET_PREFIX=10.0.0
IP_NETMASK=255.255.255.0

# Install Deps
apt-get update
apt-get install -y --no-install-recommends \
  bridge-utils \
  crda \
  dnsmasq \
  haveged \
  hostapd \
  nmap \
  rng-tools

# Set Wifi to good country
iw reg set BE

#Stop unused services/interfaces
service hostapd stop
service dnsmasq stop

# Clean and Stop interface or nothing
ip addr flush dev "${ETH_INTERFACE}" || :
ifdown "${ETH_INTERFACE}" || : 
# Clean and Stop interface or nothing
ip addr flush dev "${BRIDGE_INTERFACE}" || :
ifdown "${BRIDGE_INTERFACE}" || :

# Create the "virtual" Wifi interface for access point
[ $(iw dev | grep "${VIRT_WIFI_INTERFACE}" | wc -l) -eq 1 ] || \
  iw dev "${WIFI_INTERFACE}" interface add "${VIRT_WIFI_INTERFACE}" type __ap

# Set the Ethernet interface in manual mode
cat <<EOF >/etc/network/interfaces.d/${ETH_INTERFACE}
auto ${ETH_INTERFACE}
iface ${ETH_INTERFACE} inet manual
EOF

ifup "${ETH_INTERFACE}"

# Create the bridge and associate the Ethernet to this
cat <<EOF >/etc/network/interfaces.d/${BRIDGE_INTERFACE}
auto ${BRIDGE_INTERFACE}
iface ${BRIDGE_INTERFACE} inet static
  address ${IP_NET_PREFIX}.1
  netmask ${IP_NETMASK}
  network ${IP_NET_PREFIX}.0
  broadcast ${IP_NET_PREFIX}.255
  bridge_ports ${ETH_INTERFACE}
EOF

ifup "${BRIDGE_INTERFACE}"

# Configure hostpad to serve AP to "interface=" and be added to "bridge"
cat <<EOF >> /etc/hostapd/hostapd.conf
ssid=PI3
wpa_passphrase=raspberry
interface=${VIRT_WIFI_INTERFACE}
bridge=${BRIDGE_INTERFACE}
country_code=DE
auth_algs=3
channel=6
driver=nl80211
hw_mode=g
max_num_sta=5
rsn_pairwise=CCMP
wpa=2
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP CCMP
EOF
echo 'DAEMON_CONF="/etc/hostapd/hostapd.conf"' >> /etc/default/hostapd

# Configure dnsmasq
mv /etc/dnsmasq.conf /etc/dnsmasq.conf.bkp
touch /etc/dnsmasq.conf
echo "interface=${BRIDGE_INTERFACE}" >> /etc/dnsmasq.conf
echo "dhcp-range=${IP_NET_PREFIX}.1,${IP_NET_PREFIX}.254,12h" >> /etc/dnsmasq.conf

# Enable NAT and forwarding
sysctl -w net.ipv4.ip_forward=1
iptables -t nat -A POSTROUTING -j MASQUERADE

# Start services
systemctl enable dnsmasq
systemctl restart dnsmasq
systemctl enable hostapd
systemctl restart hostapd

sleep 5

brctl show
ip addr