wgengine/magicsock: extract IMDS utilities into a standalone package (#18334)

Moves magicksock.cloudInfo into util/cloudinfo with minimal changes.

Updates #17796

Change-Id: I83f32473b9180074d5cdbf00fa31e5b3f579f189

Signed-off-by: Alex Valiushko <alexvaliushko@tailscale.com>

cmd/k8s-operator/depaware.txt

@@ -856,6 +856,7 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
         tailscale.com/util/cibuild                                   from tailscale.com/health+
         tailscale.com/util/clientmetric                              from tailscale.com/cmd/k8s-operator+
         tailscale.com/util/cloudenv                                  from tailscale.com/hostinfo+
+        tailscale.com/util/cloudinfo                                 from tailscale.com/wgengine/magicsock
   LW    tailscale.com/util/cmpver                                    from tailscale.com/net/dns+
         tailscale.com/util/ctxkey                                    from tailscale.com/client/tailscale/apitype+
      💣 tailscale.com/util/deephash                                  from tailscale.com/util/syspolicy/setting

cmd/tailscaled/depaware-min.txt

@@ -149,6 +149,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/util/cibuild                                   from tailscale.com/health+
         tailscale.com/util/clientmetric                              from tailscale.com/appc+
         tailscale.com/util/cloudenv                                  from tailscale.com/hostinfo+
+        tailscale.com/util/cloudinfo                                 from tailscale.com/wgengine/magicsock
         tailscale.com/util/ctxkey                                    from tailscale.com/client/tailscale/apitype+
         tailscale.com/util/dnsname                                   from tailscale.com/appc+
         tailscale.com/util/eventbus                                  from tailscale.com/control/controlclient+

cmd/tailscaled/depaware-minbox.txt

@@ -176,6 +176,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/util/cibuild                                   from tailscale.com/health+
         tailscale.com/util/clientmetric                              from tailscale.com/appc+
         tailscale.com/util/cloudenv                                  from tailscale.com/hostinfo+
+        tailscale.com/util/cloudinfo                                 from tailscale.com/wgengine/magicsock
         tailscale.com/util/cmpver                                    from tailscale.com/clientupdate
         tailscale.com/util/ctxkey                                    from tailscale.com/client/tailscale/apitype+
         tailscale.com/util/dnsname                                   from tailscale.com/appc+

cmd/tailscaled/depaware.txt

@@ -422,6 +422,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/util/cibuild                                   from tailscale.com/health+
         tailscale.com/util/clientmetric                              from tailscale.com/control/controlclient+
         tailscale.com/util/cloudenv                                  from tailscale.com/net/dns/resolver+
+        tailscale.com/util/cloudinfo                                 from tailscale.com/wgengine/magicsock
         tailscale.com/util/cmpver                                    from tailscale.com/net/dns+
         tailscale.com/util/ctxkey                                    from tailscale.com/ipn/ipnlocal+
      💣 tailscale.com/util/deephash                                  from tailscale.com/util/syspolicy/setting

cmd/tsidp/depaware.txt

@@ -260,6 +260,7 @@ tailscale.com/cmd/tsidp dependencies: (generated by github.com/tailscale/depawar
         tailscale.com/util/cibuild                                   from tailscale.com/health+
         tailscale.com/util/clientmetric                              from tailscale.com/appc+
         tailscale.com/util/cloudenv                                  from tailscale.com/hostinfo+
+        tailscale.com/util/cloudinfo                                 from tailscale.com/wgengine/magicsock
   LW    tailscale.com/util/cmpver                                    from tailscale.com/net/dns+
         tailscale.com/util/ctxkey                                    from tailscale.com/client/tailscale/apitype+
      💣 tailscale.com/util/deephash                                  from tailscale.com/util/syspolicy/setting

tsnet/depaware.txt

@@ -255,6 +255,7 @@ tailscale.com/tsnet dependencies: (generated by github.com/tailscale/depaware)
         tailscale.com/util/cibuild                                   from tailscale.com/health+
         tailscale.com/util/clientmetric                              from tailscale.com/appc+
         tailscale.com/util/cloudenv                                  from tailscale.com/hostinfo+
+        tailscale.com/util/cloudinfo                                 from tailscale.com/wgengine/magicsock
   LW    tailscale.com/util/cmpver                                    from tailscale.com/net/dns+
         tailscale.com/util/ctxkey                                    from tailscale.com/client/tailscale/apitype+
      💣 tailscale.com/util/deephash                                  from tailscale.com/util/syspolicy/setting

util/cloudinfo/cloudinfo.go

@@ -3,7 +3,8 @@
 
 //go:build !(ios || android || js)
 
-package magicsock
+// Package cloudinfo provides cloud metadata utilities.
+package cloudinfo
 
 import (
 	"context"
@@ -24,7 +25,8 @@ import (
 
 const maxCloudInfoWait = 2 * time.Second
 
-type cloudInfo struct {
+// CloudInfo holds state used in querying instance metadata (IMDS) endpoints.
+type CloudInfo struct {
 	client http.Client
 	logf   logger.Logf
 
@@ -34,7 +36,8 @@ type cloudInfo struct {
 	endpoint string
 }
 
-func newCloudInfo(logf logger.Logf) *cloudInfo {
+// New constructs a new [*CloudInfo] that will log to the provided logger instance.
+func New(logf logger.Logf) *CloudInfo {
 	if !buildfeatures.HasCloud {
 		return nil
 	}
@@ -45,7 +48,7 @@ func newCloudInfo(logf logger.Logf) *cloudInfo {
 		}).Dial,
 	}
 
-	return &cloudInfo{
+	return &CloudInfo{
 		client:   http.Client{Transport: tr},
 		logf:     logf,
 		cloud:    cloudenv.Get(),
@@ -56,7 +59,9 @@ func newCloudInfo(logf logger.Logf) *cloudInfo {
 // GetPublicIPs returns any public IPs attached to the current cloud instance,
 // if the tailscaled process is running in a known cloud and there are any such
 // IPs present.
-func (ci *cloudInfo) GetPublicIPs(ctx context.Context) ([]netip.Addr, error) {
+//
+// Currently supports only AWS.
+func (ci *CloudInfo) GetPublicIPs(ctx context.Context) ([]netip.Addr, error) {
 	if !buildfeatures.HasCloud {
 		return nil, nil
 	}
@@ -73,7 +78,7 @@ func (ci *cloudInfo) GetPublicIPs(ctx context.Context) ([]netip.Addr, error) {
 // getAWSMetadata makes a request to the AWS metadata service at the given
 // path, authenticating with the provided IMDSv2 token. The returned metadata
 // is split by newline and returned as a slice.
-func (ci *cloudInfo) getAWSMetadata(ctx context.Context, token, path string) ([]string, error) {
+func (ci *CloudInfo) getAWSMetadata(ctx context.Context, token, path string) ([]string, error) {
 	req, err := http.NewRequestWithContext(ctx, "GET", ci.endpoint+path, nil)
 	if err != nil {
 		return nil, fmt.Errorf("creating request to %q: %w", path, err)
@@ -105,7 +110,7 @@ func (ci *cloudInfo) getAWSMetadata(ctx context.Context, token, path string) ([]
 }
 
 // getAWS returns all public IPv4 and IPv6 addresses present in the AWS instance metadata.
-func (ci *cloudInfo) getAWS(ctx context.Context) ([]netip.Addr, error) {
+func (ci *CloudInfo) getAWS(ctx context.Context) ([]netip.Addr, error) {
 	ctx, cancel := context.WithTimeout(ctx, maxCloudInfoWait)
 	defer cancel()
 

util/cloudinfo/cloudinfo_nocloud.go

@@ -0,0 +1,26 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build ios || android || js
+
+package cloudinfo
+
+import (
+	"context"
+	"net/netip"
+
+	"tailscale.com/types/logger"
+)
+
+// CloudInfo is not available in mobile and JS targets.
+type CloudInfo struct{}
+
+// New construct a no-op CloudInfo stub.
+func New(_ logger.Logf) *CloudInfo {
+	return &CloudInfo{}
+}
+
+// GetPublicIPs always returns nil slice and error.
+func (ci *CloudInfo) GetPublicIPs(_ context.Context) ([]netip.Addr, error) {
+	return nil, nil
+}

util/cloudinfo/cloudinfo_test.go

@@ -1,7 +1,7 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-package magicsock
+package cloudinfo
 
 import (
 	"context"
@@ -44,7 +44,7 @@ func TestCloudInfo_AWS(t *testing.T) {
 	srv := httptest.NewServer(fake)
 	defer srv.Close()
 
-	ci := newCloudInfo(t.Logf)
+	ci := New(t.Logf)
 	ci.cloud = cloudenv.AWS
 	ci.endpoint = srv.URL
 
@@ -76,7 +76,7 @@ func TestCloudInfo_AWSNotPublic(t *testing.T) {
 	srv := httptest.NewServer(returns404)
 	defer srv.Close()
 
-	ci := newCloudInfo(t.Logf)
+	ci := New(t.Logf)
 	ci.cloud = cloudenv.AWS
 	ci.endpoint = srv.URL
 

wgengine/magicsock/cloudinfo_nocloud.go

@@ -1,23 +0,0 @@
-// Copyright (c) Tailscale Inc & AUTHORS
-// SPDX-License-Identifier: BSD-3-Clause
-
-//go:build ios || android || js
-
-package magicsock
-
-import (
-	"context"
-	"net/netip"
-
-	"tailscale.com/types/logger"
-)
-
-type cloudInfo struct{}
-
-func newCloudInfo(_ logger.Logf) *cloudInfo {
-	return &cloudInfo{}
-}
-
-func (ci *cloudInfo) GetPublicIPs(_ context.Context) ([]netip.Addr, error) {
-	return nil, nil
-}

wgengine/magicsock/magicsock.go

@@ -60,6 +60,7 @@ import (
 	"tailscale.com/types/nettype"
 	"tailscale.com/types/views"
 	"tailscale.com/util/clientmetric"
+	"tailscale.com/util/cloudinfo"
 	"tailscale.com/util/eventbus"
 	"tailscale.com/util/mak"
 	"tailscale.com/util/ringlog"
@@ -213,7 +214,7 @@ type Conn struct {
 	bind *connBind
 
 	// cloudInfo is used to query cloud metadata services.
-	cloudInfo *cloudInfo
+	cloudInfo *cloudinfo.CloudInfo
 
 	// ============================================================
 	// Fields that must be accessed via atomic load/stores.
@@ -597,7 +598,7 @@ func newConn(logf logger.Logf) *Conn {
 		peerLastDerp: make(map[key.NodePublic]int),
 		peerMap:      newPeerMap(),
 		discoInfo:    make(map[key.DiscoPublic]*discoInfo),
-		cloudInfo:    newCloudInfo(logf),
+		cloudInfo:    cloudinfo.New(logf),
 	}
 	c.discoAtomic.Set(discoPrivate)
 	c.bind = &connBind{Conn: c, closed: true}