util/linuxfw: add new arch build constraints

Exclide GOARCHs including: mips, mips64, mips64le, mipsle, riscv64.
These archs are not supported by gvisor.dev/gvisor/pkg/hostarch.

Fixes: #391
Signed-off-by: KevinLiang10 <kevinliang@tailscale.com>

util/linuxfw/iptables.go

@@ -1,7 +1,8 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-//go:build linux && !(386 || loong64 || arm || armbe)
+// TODO(#8502): add support for more architectures
+//go:build linux && (arm64 || amd64)
 
 package linuxfw
 

util/linuxfw/linuxfw_struct_linux_test.go

@@ -1,7 +1,8 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-//go:build linux && !(386 || loong64 || arm || armbe)
+// TODO(#8502): add support for more architectures
+//go:build linux && (arm64 || amd64)
 
 package linuxfw
 

util/linuxfw/linuxfw_unsupported.go

@@ -1,10 +1,11 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-// NOTE: linux_{386,loong64,arm,armbe} are currently unsupported due to missing
+// NOTE: linux_{arm64, x86} are the only two currently supported archs due to missing
 // support in upstream dependencies.
 
-//go:build !linux || (linux && (386 || loong64 || arm || armbe))
+// TODO(#8502): add support for more architectures
+//go:build !linux || (linux && !(arm64 || amd64))
 
 package linuxfw
 

util/linuxfw/nftables.go

@@ -1,7 +1,8 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-//go:build linux && !(386 || loong64 || arm || armbe)
+// TODO(#8502): add support for more architectures
+//go:build linux && (arm64 || amd64)
 
 package linuxfw
 

util/linuxfw/nftables_types.go

@@ -1,7 +1,8 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-//go:build linux && !(386 || loong64 || arm || armbe)
+// TODO(#8502): add support for more architectures
+//go:build linux && (arm64 || amd64)
 
 package linuxfw