Configure hotspot

Network

Step 1 - Create custom recipe

In order to create wireless access point (hotspot) you have to configure hostapd service. Create custom recipe which will be appending instructions to original recipe.

mkdir -p ../meta-golemos/recipes-connectivity/hostapd/files
touch ../meta-golemos/recipes-connectivity/hostapd/hostapd_%.bbappend

Inside this recipe place this instructions.

FILESEXTRAPATHS_prepend := "${THISDIR}/files:"

SRC_URI += " \
    file://wlan0.conf \
    file://hostapd@.service \
"

SYSTEMD_AUTO_ENABLE = "enable"
SYSTEMD_SERVICE_${PN}_append = " hostapd@wlan0.service "

do_install_append () {
    install -d ${D}${sysconfdir}/hostapd
    install -D -m 600 ${WORKDIR}/wlan0.conf ${D}${sysconfdir}/hostapd/

    install -d ${D}${systemd_system_unitdir}
    install -D -m 0644 ${WORKDIR}/hostapd@.service ${D}${systemd_system_unitdir}/

    install -d ${D}${sysconfdir}/systemd/system/multi-user.target.wants/
    ln -s ${systemd_system_unitdir}/hostapd@.service ${D}${sysconfdir}/systemd/system/multi-user.target.wants/hostapd@wlan0.service
}

Note

This instruction enable interface specific version of the service. It will automaticly wait for the interface to be operational before started.

Step 2 - Create configuration file

Inside this file will be placed information about wireless network and also credentials to this network.

touch ../meta-golemos/recipes-connectivity/hostapd/files/wlan0.conf

In this file you have to write this configuration.

interface=wlan0
ssid=Datalogger_AP
hw_mode=g
channel=11
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
own_ip_addr=192.168.8.1
wpa=2
wpa_passphrase=datalogger
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP

Step 3 - Create service file

To match custom recipe instructions you have to create special service file for hostapd.

touch ../meta-golemos/recipes-connectivity/hostapd/files/hostapd@.service

Inside this file you should place such content.

[Unit]
Description=Advanced IEEE 802.11 AP and IEEE 802.1X/WPA/WPA2/EAP Authenticator (%I)
After=network.target
BindsTo=sys-subsystem-net-devices-%i.device

[Service]
Type=forking
PIDFile=/run/hostapd.%i.pid
Restart=on-failure
RestartSec=2
EnvironmentFile=-/etc/default/hostapd
ExecStart=/usr/sbin/hostapd -B -P /run/hostapd.%i.pid $DAEMON_OPTS /etc/hostapd/%i.conf

[Install]
WantedBy=multi-user.target sys-subsystem-net-devices-%i.device

DHCP server

In newer versions of yocto they remove isc-dhcp-server and replaced it with kea.

Step 1 - Create custom recipe

In order to configure DHCP server you need to create custom recipe which will install configuration file in proper location.

mkdir -p ../meta-golemos/recipes-connectivity/kea/files
touch ../meta-golemos/recipes-connectivity/kea/kea_%.bbappend

In this recipe place such a configuration.

FILESEXTRAPATHS_prepend := "${THISDIR}/files:"

SRC_URI += " \
    file://kea-dhcp4.conf \
    file://kea-dhcp4.service \
"

SYSTEMD_AUTO_ENABLE = "enable"
SYSTEMD_SERVICE_${PN}_append = " kea-dhcp4.service "

FILES_${PN} += " ${systemd_system_unitdir}/kea-dhcp4-server.service "

do_install_append () {
    install -d ${D}${sysconfdir}/kea/
    install -D -m 600 ${WORKDIR}/kea-dhcp4.conf ${D}${sysconfdir}/kea/

    install -d ${D}${systemd_system_unitdir}
    install -m 0644 ${WORKDIR}/kea-dhcp4.service ${D}${systemd_system_unitdir}

    install -d ${D}${sysconfdir}/systemd/system/multi-user.target.wants/
    ln -s ${systemd_system_unitdir}/kea-dhcp4.service ${D}${sysconfdir}/systemd/system/multi-user.target.wants/kea-dhcp4.service
}

Step 2 - Create configuration file

Kea needs JSON configuration file to be installed in proper place. You already have instructions which will place this file. Now create this file and configure DHCP server.

touch ../meta-golemos/recipes-connectivity/kea/files/kea-dhcp4.conf

{
"Dhcp4": {
    "valid-lifetime": 1296000,
    "renew-timer": 864000,
    "rebind-timer": 864000,
    "expired-leases-processing": {
        "reclaim-timer-wait-time": 10,
        "flush-reclaimed-timer-wait-time": 25,
        "hold-reclaimed-time": 3600,
        "max-reclaim-leases": 100,
        "max-reclaim-time": 250,
        "unwarned-reclaim-cycles": 5
    },

   "interfaces-config": {
            "interfaces": [ "wlan0/192.168.8.1" ]
    },

    "lease-database": {
        "type": "memfile",
        "persist": true,
        "name": "/var/lib/kea/dhcp4.leases",
        "lfc-interval": 3600
    },

    "subnet4": [
        {
            "subnet": "192.168.8.0/24",
            "pools": [
                {
                     "pool": "192.168.8.100 - 192.168.8.200"
                }
            ],
            "option-data": [
                {
                    "name": "routers",
                    "data": "192.168.8.0"
                }
            ]
        }
    ]
}

}

Step 3 - Create service file

Kea by itself install service file. Unfortunately this service file is really slow. In this case you have to create your own custom service file.

touch ../meta-golemos/recipes-connectivity/kea/files/kea-dhcp4.service

Inside newly created service file place such content, but first read warning underneath the code block.

[Unit]
Description=Kea DHCPv4 Server
Documentation=man:kea-dhcp4(8)
# Wants=network-online.target
# After=network-online.target

# Start after interface is up
BindsTo=sys-subsystem-net-devices-wlan0.device
After=sys-subsystem-net-devices-wlan0.device

[Service]
ExecStartPre=/sbin/ifconfig wlan0 192.168.8.1 netmask 255.255.255.0 up
ExecStartPre=/bin/mkdir -p /var/run/kea/
ExecStartPre=/bin/mkdir -p /var/lib/kea
ExecStart=/usr/sbin/kea-dhcp4 -c /etc/kea/kea-dhcp4.conf
ExecStopPost=/sbin/ifconfig wlan0 0

[Install]
WantedBy=multi-user.target

Warning

Kea install by itself service file, but custom recipe will overwrite it. This is required to set static IP before DHCP server starts and also because Kea by default wait for network-online.target. In this case it is not necessary. The minimal requirement is that the interface must be configured.

Summary

Combining this two tools will allow you to create hotspot on your device and enabling it on system boot. Following this steps should provide you to this layer structure.

../meta-golemos
├── COPYING.MIT
├── README
├── conf
│   ├── bblayers.conf.sample
│   ├── conf-notes.txt
│   ├── distro
│   │   └── golemos.conf
│   ├── layer.conf
│   └── local.conf.sample
├── recipes-connectivity
│   ├── hostapd
│   │   ├── files
│   │   │   ├── hostapd@.service
│   │   │   └── wlan0.conf
│   │   └── hostapd_%.bbappend
│   ├── kea
│   │   ├── files
│   │   │   ├── kea-dhcp4.conf
│   │   │   └── kea-dhcp4.service
│   │   └── kea_%.bbappend
│   └── wpa-supplicant
│       ├── files
│       │   └── wpa_supplicant-nl80211-wlan0.conf
│       └── wpa-supplicant_%.bbappend
├── recipes-core
│   ├── images
│   │   ├── datalogger-dev-image.bb
│   │   ├── datalogger-extended-image.bb
│   │   └── datalogger-image.bb
│   ├── packagegroups
│   │   ├── datalogger-base-packagegroup.bb
│   │   ├── datalogger-core-packagegroup.bb
│   │   ├── datalogger-dev-packagegroup.bb
│   │   └── datalogger-extended-packagegroup.bb
│   ├── systemd
│   │   └── systemd_%.bbappend
│   └── systemd-conf
│       ├── files
│       │   └── wlan.network
│       └── systemd-conf_%.bbappend
└── recipes-example
    └── example
        └── example_0.1.bb