1 files changed, 120 insertions, 0 deletions
diff --git a/nixpkgs/nixos/tests/nat.nix b/nixpkgs/nixos/tests/nat.nix
new file mode 100644
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+++ b/nixpkgs/nixos/tests/nat.nix
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+# This is a simple distributed test involving a topology with two
+# separate virtual networks - the "inside" and the "outside" - with a
+# client on the inside network, a server on the outside network, and a
+# router connected to both that performs Network Address Translation
+# for the client.
+import ./make-test-python.nix ({ pkgs, lib, withFirewall, withConntrackHelpers ? false, ... }:
+  let
+    unit = if withFirewall then "firewall" else "nat";
+
+    routerBase =
+      lib.mkMerge [
+        { virtualisation.vlans = [ 2 1 ];
+          networking.firewall.enable = withFirewall;
+          networking.nat.internalIPs = [ "192.168.1.0/24" ];
+          networking.nat.externalInterface = "eth1";
+        }
+        (lib.optionalAttrs withConntrackHelpers {
+          networking.firewall.connectionTrackingModules = [ "ftp" ];
+          networking.firewall.autoLoadConntrackHelpers = true;
+        })
+      ];
+  in
+  {
+    name = "nat" + (if withFirewall then "WithFirewall" else "Standalone")
+                 + (lib.optionalString withConntrackHelpers "withConntrackHelpers");
+    meta = with pkgs.lib.maintainers; {
+      maintainers = [ eelco rob ];
+    };
+
+    nodes =
+      { client =
+          { pkgs, nodes, ... }:
+          lib.mkMerge [
+            { virtualisation.vlans = [ 1 ];
+              networking.defaultGateway =
+                (pkgs.lib.head nodes.router.config.networking.interfaces.eth2.ipv4.addresses).address;
+            }
+            (lib.optionalAttrs withConntrackHelpers {
+              networking.firewall.connectionTrackingModules = [ "ftp" ];
+              networking.firewall.autoLoadConntrackHelpers = true;
+            })
+          ];
+
+        router =
+        { ... }: lib.mkMerge [
+          routerBase
+          { networking.nat.enable = true; }
+        ];
+
+        routerDummyNoNat =
+        { ... }: lib.mkMerge [
+          routerBase
+          { networking.nat.enable = false; }
+        ];
+
+        server =
+          { ... }:
+          { virtualisation.vlans = [ 2 ];
+            networking.firewall.enable = false;
+            services.httpd.enable = true;
+            services.httpd.adminAddr = "foo@example.org";
+            services.vsftpd.enable = true;
+            services.vsftpd.anonymousUser = true;
+          };
+      };
+
+    testScript =
+      { nodes, ... }: let
+        routerDummyNoNatClosure = nodes.routerDummyNoNat.config.system.build.toplevel;
+        routerClosure = nodes.router.config.system.build.toplevel;
+      in ''
+        client.start()
+        router.start()
+        server.start()
+
+        # The router should have access to the server.
+        server.wait_for_unit("network.target")
+        server.wait_for_unit("httpd")
+        router.wait_for_unit("network.target")
+        router.succeed("curl --fail http://server/ >&2")
+
+        # The client should be also able to connect via the NAT router.
+        router.wait_for_unit("${unit}")
+        client.wait_for_unit("network.target")
+        client.succeed("curl --fail http://server/ >&2")
+        client.succeed("ping -c 1 server >&2")
+
+        # Test whether passive FTP works.
+        server.wait_for_unit("vsftpd")
+        server.succeed("echo Hello World > /home/ftp/foo.txt")
+        client.succeed("curl -v ftp://server/foo.txt >&2")
+
+        # Test whether active FTP works.
+        client.${if withConntrackHelpers then "succeed" else "fail"}("curl -v -P - ftp://server/foo.txt >&2")
+
+        # Test ICMP.
+        client.succeed("ping -c 1 router >&2")
+        router.succeed("ping -c 1 client >&2")
+
+        # If we turn off NAT, the client shouldn't be able to reach the server.
+        router.succeed(
+            "${routerDummyNoNatClosure}/bin/switch-to-configuration test 2>&1"
+        )
+        client.fail("curl --fail --connect-timeout 5 http://server/ >&2")
+        client.fail("ping -c 1 server >&2")
+
+        # And make sure that reloading the NAT job works.
+        router.succeed(
+            "${routerClosure}/bin/switch-to-configuration test 2>&1"
+        )
+        # FIXME: this should not be necessary, but nat.service is not started because
+        #        network.target is not triggered
+        #        (https://github.com/NixOS/nixpkgs/issues/16230#issuecomment-226408359)
+        ${lib.optionalString (!withFirewall) ''
+          router.succeed("systemctl start nat.service")
+        ''}
+        client.succeed("curl --fail http://server/ >&2")
+        client.succeed("ping -c 1 server >&2")
+      '';
+  })