treewide: move HostInterfaceMAC to a tracked duplicate var

This is required to not accidentally pull-in future qemu runfiles.

Change-Id: I6098900d047f21096c0b1f6b2176d2480f8e6ab0
Reviewed-on: https://review.monogon.dev/c/monogon/+/4054
Tested-by: Jenkins CI
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
diff --git a/metropolis/test/nanoswitch/BUILD.bazel b/metropolis/test/nanoswitch/BUILD.bazel
index 4cee5ba..d7f9d12 100644
--- a/metropolis/test/nanoswitch/BUILD.bazel
+++ b/metropolis/test/nanoswitch/BUILD.bazel
@@ -16,7 +16,6 @@
         "//osbase/bringup",
         "//osbase/socksproxy",
         "//osbase/supervisor",
-        "//osbase/test/qemu",
         "@com_github_google_nftables//:nftables",
         "@com_github_google_nftables//expr",
         "@com_github_insomniacslk_dhcp//dhcpv4",
diff --git a/metropolis/test/nanoswitch/nanoswitch.go b/metropolis/test/nanoswitch/nanoswitch.go
index 59c4b59..c3fde27 100644
--- a/metropolis/test/nanoswitch/nanoswitch.go
+++ b/metropolis/test/nanoswitch/nanoswitch.go
@@ -33,11 +33,18 @@
 	dhcpcb "source.monogon.dev/metropolis/node/core/network/dhcp4c/callback"
 	"source.monogon.dev/osbase/bringup"
 	"source.monogon.dev/osbase/supervisor"
-	"source.monogon.dev/osbase/test/qemu"
 )
 
-var switchIP = net.IP{10, 1, 0, 1}
-var switchSubnetMask = net.CIDRMask(24, 32)
+var (
+	// HostInterfaceMAC is the MAC address the host SLIRP network interface has if it
+	// is not disabled (see DisableHostNetworkInterface in MicroVMOptions)
+	// ONCHANGE(//osbase/test/qemu:launch.go): constraints must be kept in sync with
+	// HostInterfaceMAC.
+	HostInterfaceMAC = net.HardwareAddr{0x02, 0x72, 0x82, 0xbf, 0xc3, 0x56}
+
+	switchIP         = net.IP{10, 1, 0, 1}
+	switchSubnetMask = net.CIDRMask(24, 32)
+)
 
 // defaultLeaseOptions sets the lease options needed to properly configure
 // connectivity to nanoswitch.
@@ -208,7 +215,7 @@
 			if attrs.Flags&net.FlagUp != net.FlagUp {
 				netlink.LinkSetUp(link) // Attempt to take up all ethernet links
 			}
-			if bytes.Equal(attrs.HardwareAddr, qemu.HostInterfaceMAC) {
+			if bytes.Equal(attrs.HardwareAddr, HostInterfaceMAC) {
 				externalLink = link
 			} else {
 				vmLinks = append(vmLinks, link)
diff --git a/osbase/test/qemu/launch.go b/osbase/test/qemu/launch.go
index 52a1492..1b063de 100644
--- a/osbase/test/qemu/launch.go
+++ b/osbase/test/qemu/launch.go
@@ -22,6 +22,12 @@
 	"source.monogon.dev/osbase/freeport"
 )
 
+var (
+	// HostInterfaceMAC is the MAC address the host SLIRP network interface has if it
+	// is not disabled (see DisableHostNetworkInterface in MicroVMOptions)
+	HostInterfaceMAC = net.HardwareAddr{0x02, 0x72, 0x82, 0xbf, 0xc3, 0x56}
+)
+
 type QemuValue map[string][]string
 
 // ToOption encodes structured data into a QEMU option. Example: "test", {"key1":
@@ -130,10 +136,6 @@
 	return fd1, fd2, nil
 }
 
-// HostInterfaceMAC is the MAC address the host SLIRP network interface has if it
-// is not disabled (see DisableHostNetworkInterface in MicroVMOptions)
-var HostInterfaceMAC = net.HardwareAddr{0x02, 0x72, 0x82, 0xbf, 0xc3, 0x56}
-
 // MicroVMOptions contains all options to start a MicroVM
 type MicroVMOptions struct {
 	// Name is a human-readable identifier to be used in debug output.