feat: support conditional start of IPv6 dns servers

This PR does those things:
- [x] Refactored `DNSResolveCacheController`. Most of the logic moved to `dns` package types. Simplify and streamline logic.
- [x] Replace most of the goroutine orchestration with suture package.
- [x] Support per-item reaction to the dns listeners/servers failing to start. This allows us to ignore IPv6 errors if it's disabled.
- [x] Support per-item reaction to the dns listeners/servers failing to stop.
- [ ] Raise IPv6 listener on link-local address for dns (both TCP and UDP).
- [ ] Update kubelet's `resolv.conf` IPv4/IPv6 endpoints.

Closes siderolabs#9384

Signed-off-by: Dmitriy Matrenichev <[email protected]>

api/resource/definitions/network/network.proto

@@ -114,6 +114,7 @@ message HostDNSConfigSpec {
   repeated common.NetIPPort listen_addresses = 2;
   common.NetIP service_host_dns_address = 3;
   bool resolve_member_names = 4;
+  common.NetIP service_host_dns_address_v6 = 5;
 }
 
 // HostnameSpecSpec describes node hostname.

go.mod

@@ -171,6 +171,7 @@ require (
 	github.com/spf13/cobra v1.8.1
 	github.com/spf13/pflag v1.0.5
 	github.com/stretchr/testify v1.9.0
+	github.com/thejerf/suture/v4 v4.0.5
 	github.com/u-root/u-root v0.14.0
 	github.com/ulikunitz/xz v0.5.12
 	github.com/vmware/vmw-guestinfo v0.0.0-20220317130741-510905f0efa3

go.sum

@@ -732,6 +732,8 @@ github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsT
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/syndtr/gocapability v0.0.0-20200815063812-42c35b437635 h1:kdXcSzyDtseVEc4yCz2qF8ZrQvIDBJLl4S1c3GCXmoI=
 github.com/syndtr/gocapability v0.0.0-20200815063812-42c35b437635/go.mod h1:hkRG7XYTFWNJGYcbNJQlaLq0fg1yr4J4t/NcTQtrfww=
+github.com/thejerf/suture/v4 v4.0.5 h1:F1E/4FZwXWqvlWDKEUo6/ndLtxGAUzMmNqkrMknZbAA=
+github.com/thejerf/suture/v4 v4.0.5/go.mod h1:gu9Y4dXNUWFrByqRt30Rm9/UZ0wzRSt9AJS6xu/ZGxU=
 github.com/u-root/u-root v0.14.0 h1:Ka4T10EEML7dQ5XDvO9c3MBN8z4nuSnGjcd1jmU2ivg=
 github.com/u-root/u-root v0.14.0/go.mod h1:hAyZorapJe4qzbLWlAkmSVCJGbfoU9Pu4jpJ1WMluqE=
 github.com/u-root/uio v0.0.0-20240224005618-d2acac8f3701 h1:pyC9PaHYZFgEKFdlp3G8RaCKgVpHZnecvArXvPXcFkM=

internal/app/machined/pkg/controllers/network/address_spec_test.go

@@ -28,6 +28,7 @@ import (
 	"golang.org/x/sys/unix"
 
 	netctrl "github.com/siderolabs/talos/internal/app/machined/pkg/controllers/network"
+	"github.com/siderolabs/talos/pkg/machinery/constants"
 	"github.com/siderolabs/talos/pkg/machinery/nethelpers"
 	"github.com/siderolabs/talos/pkg/machinery/resources/network"
 )
@@ -170,6 +171,47 @@ func (suite *AddressSpecSuite) TestLoopback() {
 	suite.Require().NoError(suite.state.Destroy(suite.ctx, loopback.Metadata()))
 }
 
+func (suite *AddressSpecSuite) TestIPV6ULA() {
+	loopback := network.NewAddressSpec(network.NamespaceName, "lo/"+constants.HostDNSAddressV6+"/128")
+	*loopback.TypedSpec() = network.AddressSpecSpec{
+		Address:     netip.MustParsePrefix(constants.HostDNSAddressV6 + "/128"),
+		LinkName:    "lo",
+		Family:      nethelpers.FamilyInet6,
+		Scope:       nethelpers.ScopeGlobal,
+		ConfigLayer: network.ConfigDefault,
+		Flags:       nethelpers.AddressFlags(nethelpers.AddressPermanent),
+	}
+
+	for _, res := range []resource.Resource{loopback} {
+		suite.Require().NoError(suite.state.Create(suite.ctx, res), "%v", res.Spec())
+	}
+
+	suite.Assert().NoError(
+		retry.Constant(3*time.Second, retry.WithUnits(100*time.Millisecond)).Retry(
+			func() error {
+				return suite.assertLinkAddress("lo", constants.HostDNSAddressV6+"/128")
+			},
+		),
+	)
+
+	// teardown the address
+	for {
+		ready, err := suite.state.Teardown(suite.ctx, loopback.Metadata())
+		suite.Require().NoError(err)
+
+		if ready {
+			break
+		}
+
+		time.Sleep(100 * time.Millisecond)
+	}
+
+	// torn down address should be removed immediately
+	suite.Assert().NoError(suite.assertNoLinkAddress("lo", constants.HostDNSAddressV6+"/128"))
+
+	suite.Require().NoError(suite.state.Destroy(suite.ctx, loopback.Metadata()))
+}
+
 func (suite *AddressSpecSuite) TestDummy() {
 	dummyInterface := suite.uniqueDummyInterface()