services: network-manager: Use record for configuration.

* gnu/services/network-manager.scm (<network-manager-configuration>): New
record type.
(network-manager-shpeherd-service): Change to use the
network-manager-configuration record, rather than a package.  Generate a
simple configuration file from the network-manager-configuration record.
(network-manager-service-type): Update extensions to take the
network-manager-configuration rather than a package.
(network-manager-service): Remove function, the network-manager-service-type
can be used instead, and this avoids keeping the function signature and value
coresponding to the service type in sync.
* doc/guix.texi (Networking Services): Remove documentation for the removed
network-manager-service procedure, and add documentation of the
network-manager-service-type variable and network-manager-configuration
record.

Signed-off-by: 宋文武 <iyzsong@member.fsf.org>

doc/guix.texi

@@ -8758,11 +8758,41 @@ and @command{wicd-curses} user interfaces.
 @end deffn
 
 @cindex NetworkManager
-@deffn {Scheme Procedure} network-manager-service @
-       [#:network-manager @var{network-manager}]
-Return a service that runs NetworkManager, a network connection manager
-attempting to keep network connectivity active when available.
-@end deffn
+
+@defvr {Scheme Variable} network-manager-service-type
+This is the service type for the
+@uref{https://wiki.gnome.org/Projects/NetworkManager, NetworkManager}
+service. The value for this service type is a
+@code{network-manager-configuration} record.
+@end defvr
+
+@deftp {Data Type} network-manager-configuration
+Data type representing the configuration of NetworkManager.
+
+@table @asis
+@item @code{network-manager} (default: @code{network-manager})
+The NetworkManager package to use.
+
+@item @code{dns} (default: @code{"default"})
+Processing mode for DNS, which affects how NetworkManager uses the
+@code{resolv.conf} configuration file.
+
+@table @samp
+@item default
+NetworkManager will update @code{resolv.conf} to reflect the nameservers
+provided by currently active connections.
+
+@item dnsmasq
+NetworkManager will run @code{dnsmasq} as a local caching nameserver,
+using a "split DNS" configuration if you are connected to a VPN, and
+then update @code{resolv.conf} to point to the local nameserver.
+
+@item none
+NetworkManager will not modify @code{resolv.conf}.
+@end table
+
+@end table
+@end deftp
 
 @cindex Connman
 @deffn {Scheme Procedure} connman-service @

gnu/services/networking.scm

@@ -64,7 +64,12 @@
 
             wicd-service-type
             wicd-service
-            network-manager-service
+
+            network-manager-configuration
+            network-manager-configuration?
+            network-manager-configuration-dns
+            network-manager-service-type
+
             connman-service
             wpa-supplicant-service-type))
 
@@ -679,14 +684,29 @@ and @command{wicd-curses} user interfaces."
 ;;; NetworkManager
 ;;;
 
+(define-record-type* <network-manager-configuration>
+  network-manager-configuration make-network-manager-configuration
+  network-manager-configuration?
+  (network-manager network-manager-configuration-network-manager
+                   (default network-manager))
+  (dns network-manager-configuration-dns
+       (default "default")))
+
 (define %network-manager-activation
   ;; Activation gexp for NetworkManager.
   #~(begin
       (use-modules (guix build utils))
       (mkdir-p "/etc/NetworkManager/system-connections")))
 
-(define (network-manager-shepherd-service network-manager)
-  "Return a shepherd service for NETWORK-MANAGER."
+(define network-manager-shepherd-service
+  (match-lambda
+    (($ <network-manager-configuration> network-manager dns)
+     (let
+         ((conf (plain-file "NetworkManager.conf"
+                            (string-append "
+[main]
+dns=" dns "
+"))))
      (list (shepherd-service
             (documentation "Run the NetworkManager.")
             (provision '(networking))
@@ -694,25 +714,28 @@ and @command{wicd-curses} user interfaces."
             (start #~(make-forkexec-constructor
                       (list (string-append #$network-manager
                                            "/sbin/NetworkManager")
+                            (string-append "--config=" #$conf)
                             "--no-daemon")))
-         (stop #~(make-kill-destructor)))))
+            (stop #~(make-kill-destructor))))))))
 
 (define network-manager-service-type
-  (service-type (name 'network-manager)
+  (let
+      ((config->package
+        (match-lambda
+         (($ <network-manager-configuration> network-manager)
+          (list network-manager)))))
+
+    (service-type
+     (name 'network-manager)
      (extensions
       (list (service-extension shepherd-root-service-type
                                network-manager-shepherd-service)
-                       (service-extension dbus-root-service-type list)
-                       (service-extension polkit-service-type list)
+            (service-extension dbus-root-service-type config->package)
+            (service-extension polkit-service-type config->package)
             (service-extension activation-service-type
                                (const %network-manager-activation))
             ;; Add network-manager to the system profile.
-                       (service-extension profile-service-type list)))))
-
-(define* (network-manager-service #:key (network-manager network-manager))
-  "Return a service that runs NetworkManager, a network connection manager
-that attempting to keep active network connectivity when available."
-  (service network-manager-service-type network-manager))
+            (service-extension profile-service-type config->package))))))
 
 
 ;;;