Discuss an example configuration for a wireless ISP.

Update the Configure Core NetworkD and Configure Gate NetworkD
sections.

Do not bother NetworkD when UdevD configurations change.  A reboot
will be necessary.

diff --git a/README.org b/README.org
index 66833ad7aaaed3aa78fbd0c9a510a0ff13dcd4f6..394bbf0fd8123f3f69b7f005bfb7e35e51af97b3 100644 (file)
--- a/README.org
+++ b/README.org
@@ -1244,8 +1244,8 @@ Gate was also connected to the USB Ethernet dongles cabled to the
 campus Wi-Fi access point and the campus ISP and the values of three
 variables (~gate_lan_mac~, ~gate_wild_mac~, and ~gate_isp_mac~ in
 [[file:private/vars.yml][=private/vars.yml=]]) match the actual hardware MAC addresses of the
-dongles.  (For more information, see the tasks in section [[Configure
-Gate NetworkD]].)
+dongles.  (For more information, see the tasks in the [[Configure Gate
+NetworkD]] section.)
 
 At this point Gate was prepared for provisioning with Ansible.
 
@@ -2595,19 +2595,19 @@ list, and to disable its cache and stub listener.
 ** Configure Core NetworkD
 
 Core's network interface is statically configured using the
-~systemd-networkd~ configuration files =10-lan.link= and
-=10-lan.network= installed in =/etc/systemd/network/=.  Those files
-statically assign Core's IP address (as well as the campus name server
-and search domain), and its default route through Gate.  A second
-route, through Core itself to Front, is advertised to other hosts, and
-is routed through a WireGuard™ interface connected to Front's public
-WireGuard™ VPN.
+~systemd-udevd~ configuration file =10-lan.link= and the
+~systemd-networkd~ configuration file =10-lan.network=, both installed
+in =/etc/systemd/network/=.  Those files statically assign Core's IP
+address and its default route through Gate.  A second route, through
+Core itself to Front, is advertised to other hosts, and is routed
+through a WireGuard™ interface connected to Front's public WireGuard™
+VPN.
 
 Note that the ~[Match]~ sections of the =.network= files should
 specify only a ~MACAddress~.  Getting ~systemd-udevd~ to rename
 interfaces has thusfar been futile (short of a reboot), so specifying
-a ~Name~ means the interface does not match, leaving it un-configured
-(until the next reboot).
+a ~Name~ means the interface will not be configured until after the
+next reboot.
 
 The configuration needs the MAC address of the primary (only) NIC, an
 example of which is given here.  (A clever way to extract that name
@@ -4955,10 +4955,11 @@ The following should be familiar boilerplate by now.
 
 ** Configure Gate NetworkD
 
-Gate's network interfaces are configured using SystemD NetworkD
-configuration files that specify their MAC addresses.  (One or more
-might be plug-and-play USB dongles.)  These addresses are provided by
-the [[file:private/vars.yml][=private/vars.yml=]] file as in the example code here.
+Gate's network interfaces are configured by =.link= and =.network=
+files installed in =/etc/systemd/network=.  The files specify
+interfaces by matching their MAC addresses.  (One or more might be
+plug-and-play USB dongles.)  The addresses are provided by the
+[[file:private/vars.yml][=private/vars.yml=]] file as in the example code here.
 
 #+CAPTION: [[file:private/vars.yml][=private/vars.yml=]]
 #+BEGIN_SRC conf :tangle private/vars.yml
@@ -4967,6 +4968,9 @@ gate_wild_mac:              08:00:27:4a:de:d2
 gate_isp_mac:               08:00:27:3d:42:e5
 #+END_SRC
 
+Note that the =.network= files do not use the interface names for
+reasons discussed in the [[Configure Core NetworkD]] section.
+
 The tasks in the following sections install the necessary
 configuration files.
 
@@ -4988,7 +4992,6 @@ The campus Ethernet interface is named ~lan~ and configured by
       [Link]
       Name=lan
     dest: /etc/systemd/network/10-lan.link
-  notify: Reload networkd.
 
 - name: Install 10-lan.network.
   become: yes
@@ -5059,7 +5062,6 @@ configured by =10-wild.link= and =10-wild.network= files in
       [Link]
       Name=wild
     dest: /etc/systemd/network/10-wild.link
-  notify: Reload networkd.
 
 - name: Install 10-wild.network.
   become: yes
@@ -5111,7 +5113,6 @@ tether, Wi-Fi connection, etc.
       [Link]
       Name=isp
     dest: /etc/systemd/network/10-isp.link
-  notify: Reload networkd.
 
 - name: Install 10-isp.network.
   become: yes
@@ -5127,7 +5128,9 @@ not already exist so that it can be easily modified to debug a new
 campus ISP without interference from Ansible.
 
 The following example =gate-isp.network= file recognizes an Ethernet
-interface by its MAC address.
+interface by its MAC address and configures it as a DHCP client.  The
+block tangles to =private/gate-isp.network= as part of the test
+configuration.
 
 #+CAPTION: [[file:private/gate-isp.network][=private/gate-isp.network=]]
 #+BEGIN_SRC conf :tangle private/gate-isp.network :tangle-mode u=rw,g=,o=
@@ -5143,6 +5146,37 @@ UseMTU=true
 UseDNS=false
 #+END_SRC
 
+The same =gate-isp.link= and =gate-isp.network= files can be used to
+configure a wireless interface simply by replacing the interface MAC,
+though the machine will need to reboot in order to name the new
+interface ~isp~ and re-load the firewall rules with that new naming.
+
+Once the wireless interface is named ~isp~, WPA Supplicant can be
+supplied a configuration file like the following, and used to connect
+and authenticate.
+
+#+CAPTION: =/etc/wpa_supplicant/wpa_supplicant-isp.conf=
+#+BEGIN_SRC conf
+ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=root
+network={
+  ssid="Access Point Name"
+  scan_ssid=1
+  key_mgmt=WPA-PSK
+  psk="access point passphrase"
+}
+#+END_SRC
+
+#+BEGIN_SRC sh
+sudo systemctl start wpa_supplicant@isp
+networkctl
+sudo systemctl enable wpa_supplicant@isp
+#+END_SRC
+
+The same =gate-isp.link= and =gate-isp.network= files would also be
+used with a USB tether simply by replacing the interface MAC.  Again,
+the machine will need to reboot in order to name the interface ~isp~
+and re-load the firewall rules with that new naming.
+
 ** Configure Gate ResolveD
 
 Gate provides name service on the wild Ethernet by having its "stub