アドホックネットワーク
An IBSS (Independent Basic Service Set) network, often called an ad-hoc network, is a way to have a group of devices talk to each other wirelessly, without a central controller. It is an example of a peer-to-peer network, in which all devices talk directly to each other, with no inherent relaying.
For example, ad-hoc networking may be used to share an internet connection.
目次
要件
- A nl80211 compatible wireless device (e.g. ath9k) on all devices which will connect to the network
Wifi リンク層
Since IBSS network is a peer-to-peer network, the steps necessary to set up the wifi link layer should be the same on all devices.
手動設定
以下で使っているコマンドの詳しい説明はワイヤレス設定#手動セットアップを見て下さい。また、iw をインストールしておいてください。
動作モードを ibss に設定:
# iw interface set type ibss
インターフェイスを立ち上げる (rfkill unblock wifi などの設定が必要に鳴る場合もあります):
# ip link set interface up
Now you can create an ad-hoc network. Replace your_ssid with the name of the network and frequency with the frequency in MHz, depending on which channel you want to use. See the Wikipedia page List of WLAN channels for a table showing frequencies of individual channels.
# iw interface ibss join your_ssid frequency
WPA supplicant
Ensure that wpa_supplicant is installed, and create a configuration file for it (see WPA supplicant for details).
/etc/wpa_supplicant-adhoc.conf
ctrl_interface=DIR=/run/wpa_supplicant GROUP=wheel
# use 'ap_scan=2' on all devices connected to the network
ap_scan=2
network={
ssid="MySSID"
mode=1
frequency=2432
proto=WPA
key_mgmt=WPA-NONE
pairwise=NONE
group=TKIP
psk="secret passphrase"
}
Run wpa_supplicant on all devices connected to the network with the following command:
# wpa_supplicant -B -i interface -c /etc/wpa_supplicant-adhoc.conf -D nl80211,wext
ネットワーク設定
The final step is to assign an IP address to all devices in the network. There are multiple ways to do this:
- Assign static IP addresses. See Network configuration#Static IP address for details.
- Running DHCP server on one device. See dhcpd or dnsmasq for details.
- Running avahi-autoipd. See Avahi#Obtaining IPv4LL IP address for details.
If you want to share an internet connection to the ad-hoc network, see Internet sharing.
Tips and tricks
NetworkManager を使う
If you use NetworkManager, you can use nm-applet for ad-hoc network configuration instead of the manual method described above. See NetworkManager#Ad-hoc for details.
カスタム systemd サービス (wpa_supplicant と固定 IP)
You can use the following templates to enable wireless ad-hoc networking:
/etc/conf.d/network-wireless-adhoc@<interface>
addr=192.168.0.2 mask=24
/etc/systemd/system/network-wireless-adhoc@.service
[Unit]
Description=Ad-hoc wireless network connectivity (%i)
Wants=network.target
Before=network.target
BindsTo=sys-subsystem-net-devices-%i.device
After=sys-subsystem-net-devices-%i.device
[Service]
Type=oneshot
RemainAfterExit=yes
EnvironmentFile=/etc/conf.d/network-wireless-adhoc@%i
# perhaps rfkill is not needed for you
ExecStart=/usr/bin/rfkill unblock wifi
ExecStart=/usr/bin/ip link set %i up
ExecStart=/usr/bin/wpa_supplicant -B -i %i -D nl80211,wext -c /etc/wpa_supplicant-adhoc.conf
ExecStart=/usr/bin/ip addr add ${addr}/${mask} dev %i
ExecStop=/usr/bin/ip addr flush dev %i
ExecStop=/usr/bin/ip link set %i down
[Install]
WantedBy=multi-user.target