* Allow more complex network topologies in distributed tests. Each

machine can now declare an option `virtualisation.vlans' that causes
  it to have network interfaces connected to each listed virtual
  network.  For instance,

    virtualisation.vlans = [ 1 2 ];

  causes the machine to have two interfaces (in addition to eth0, used
  by the test driver to control the machine): eth1 connected to
  network 1 with IP address 192.168.1.<i>, and eth2 connected to
  network 2 with address 192.168.2.<i> (where <i> is the index of the
  machine in the `nodes' attribute set).  On the other hand,
  
    virtualisation.vlans = [ 2 ];

  causes the machine to only have an eth1 connected to network 2 with
  address 192.168.2.<i>.  So each virtual network <n> is assigned the
  IP range 192.168.<n>.0/24.

  Each virtual network is implemented using a separate multicast
  address on the host, so guests really cannot talk to networks to
  which they are not connected.

* Added a simple NAT test to demonstrate this.

* Added an option `virtualisation.qemu.options' to specify QEMU
  command-line options.  Used to factor out some commonality between
  the test driver script and the interactive test script.

svn path=/nixos/trunk/; revision=21928

modules/virtualisation/qemu-vm.nix

@@ -68,6 +68,37 @@ let
             database in the guest).
           '';
       };
+
+    virtualisation.vlans = 
+      mkOption {
+        default = [ 1 ];
+        example = [ 1 2 ];
+        description =
+          ''
+            Virtual networks to which the VM is connected.  Each
+            number <replaceable>N</replaceable> in this list causes
+            the VM to have a virtual Ethernet interface attached to a
+            separate virtual network on which it will be assigned IP
+            address
+            <literal>192.168.<replaceable>N</replaceable>.<replaceable>M</replaceable></literal>,
+            where <replaceable>M</replaceable> is the index of this VM
+            in the list of VMs.
+          '';
+      };
+
+    networking.primaryIPAddress =
+      mkOption {
+        default = "";
+        internal = true;
+        description = "Primary IP address used in /etc/hosts.";
+      };
+
+    virtualisation.qemu.options =
+      mkOption {
+        default = "";
+        example = "-vga std";
+        description = "Options passed to QEMU.";
+      };
       
   };
 
@@ -94,13 +125,14 @@ let
       # hanging the VM on x86_64.
       exec ${pkgs.qemu_kvm}/bin/qemu-system-x86_64 -m ${toString config.virtualisation.memorySize} \
           -no-kvm-irqchip \
-          -net nic,model=virtio -net user -smb / \
+          -net nic,vlan=0,model=virtio -net user,vlan=0 -smb / \
           -drive file=$NIX_DISK_IMAGE,if=virtio,boot=on,werror=report \
           -kernel ${config.system.build.toplevel}/kernel \
           -initrd ${config.system.build.toplevel}/initrd \
           ${qemuGraphics} \
           $QEMU_OPTS \
-          -append "$(cat ${config.system.build.toplevel}/kernel-params) init=${config.system.build.bootStage2} systemConfig=${config.system.build.toplevel} regInfo=${regInfo} ${kernelConsole} $QEMU_KERNEL_PARAMS"
+          -append "$(cat ${config.system.build.toplevel}/kernel-params) init=${config.system.build.bootStage2} systemConfig=${config.system.build.toplevel} regInfo=${regInfo} ${kernelConsole} $QEMU_KERNEL_PARAMS" \
+          ${config.virtualisation.qemu.options}
     '';
 
     
@@ -186,7 +218,7 @@ in
   # host filesystem and thus deadlocks the system.
   networking.useDHCP = false;
 
-  networking.defaultGateway = "10.0.2.2";
+  networking.defaultGateway = mkOverride 200 {} "10.0.2.2";
 
   networking.nameservers = [ "10.0.2.3" ];