ipn/ipnlocal: move tailcfg.Netinfo ownership to LocalBackendmaisem/ni

The only thing place which owned the copy of Netinfo was the controlclient,
which meant that we had another place where we were modifying the hostinfo
and blending fields in. This moves all of that logic to now occur solely
in LocalBackend.

Updates #cleanup

Signed-off-by: Maisem Ali <maisem@tailscale.com>

4 files changed, 13 insertions, 66 deletions

diff --git a/control/controlclient/auto.go b/control/controlclient/auto.go
index fa5e2e106..10f5a3781 100644
--- a/control/controlclient/auto.go
+++ b/control/controlclient/auto.go
@@ -564,18 +564,6 @@ func (c *Auto) SetHostinfo(hi *tailcfg.Hostinfo) {
 	c.updateControl()
 }
 
-func (c *Auto) SetNetInfo(ni *tailcfg.NetInfo) {
-	if ni == nil {
-		panic("nil NetInfo")
-	}
-	if !c.direct.SetNetInfo(ni) {
-		return
-	}
-
-	// Send new NetInfo to server
-	c.updateControl()
-}
-
 // SetTKAHead updates the TKA head hash that map-request infrastructure sends.
 func (c *Auto) SetTKAHead(headHash string) {
 	if !c.direct.SetTKAHead(headHash) {
diff --git a/control/controlclient/client.go b/control/controlclient/client.go
index ef5af68c6..1bd087e29 100644
--- a/control/controlclient/client.go
+++ b/control/controlclient/client.go
@@ -65,12 +65,6 @@ type Client interface {
 	// in a separate http request. It has nothing to do with the rest of
 	// the state machine.
 	SetHostinfo(*tailcfg.Hostinfo)
-	// SetNetinfo changes the NetIinfo structure that will be sent in
-	// subsequent node registration requests.
-	// TODO: a server-side change would let us simply upload this
-	// in a separate http request. It has nothing to do with the rest of
-	// the state machine.
-	SetNetInfo(*tailcfg.NetInfo)
 	// SetTKAHead changes the TKA head hash value that will be sent in
 	// subsequent netmap requests.
 	SetTKAHead(headHash string)
diff --git a/control/controlclient/direct.go b/control/controlclient/direct.go
index 80f6e919b..1b1ed78f5 100644
--- a/control/controlclient/direct.go
+++ b/control/controlclient/direct.go
@@ -20,7 +20,6 @@ import (
 	"net/netip"
 	"net/url"
 	"os"
-	"reflect"
 	"runtime"
 	"slices"
 	"strings"
@@ -50,7 +49,6 @@ import (
 	"tailscale.com/types/logger"
 	"tailscale.com/types/netmap"
 	"tailscale.com/types/persist"
-	"tailscale.com/types/ptr"
 	"tailscale.com/types/tkatype"
 	"tailscale.com/util/clientmetric"
 	"tailscale.com/util/multierr"
@@ -93,8 +91,7 @@ type Direct struct {
 	authKey      string
 	tryingNewKey key.NodePrivate
 	expiry       time.Time         // or zero value if none/unknown
-	hostinfo     *tailcfg.Hostinfo // always non-nil
-	netinfo      *tailcfg.NetInfo
+	hostinfo     *tailcfg.Hostinfo // always non-nil, never mutated only replaced
 	endpoints    []tailcfg.Endpoint
 	tkaHead      string
 	lastPingURL  string // last PingRequest.URL received, for dup suppression
@@ -289,9 +286,6 @@ func NewDirect(opts Options) (*Direct, error) {
 		c.SetHostinfo(hostinfo.New())
 	} else {
 		c.SetHostinfo(opts.Hostinfo)
-		if ni := opts.Hostinfo.NetInfo; ni != nil {
-			c.SetNetInfo(ni)
-		}
 	}
 	if opts.NoiseTestClient != nil {
 		c.noiseClient = &NoiseClient{
@@ -321,8 +315,6 @@ func (c *Direct) SetHostinfo(hi *tailcfg.Hostinfo) bool {
 	if hi == nil {
 		panic("nil Hostinfo")
 	}
-	hi = ptr.To(*hi)
-	hi.NetInfo = nil
 	c.mu.Lock()
 	defer c.mu.Unlock()
 
@@ -335,24 +327,7 @@ func (c *Direct) SetHostinfo(hi *tailcfg.Hostinfo) bool {
 	return true
 }
 
-// SetNetInfo clones the provided NetInfo and remembers it for the
-// next update. It reports whether the NetInfo has changed.
-func (c *Direct) SetNetInfo(ni *tailcfg.NetInfo) bool {
-	if ni == nil {
-		panic("nil NetInfo")
-	}
-	c.mu.Lock()
-	defer c.mu.Unlock()
-
-	if reflect.DeepEqual(ni, c.netinfo) {
-		return false
-	}
-	c.netinfo = ni.Clone()
-	c.logf("NetInfo: %v", ni)
-	return true
-}
-
-// SetNetInfo stores a new TKA head value for next update.
+// SetTKAHead stores a new TKA head value for next update.
 // It reports whether the TKA head changed.
 func (c *Direct) SetTKAHead(tkaHead string) bool {
 	c.mu.Lock()
@@ -445,14 +420,6 @@ type httpClient interface {
 	Do(req *http.Request) (*http.Response, error)
 }
 
-// hostInfoLocked returns a Clone of c.hostinfo and c.netinfo.
-// It must only be called with c.mu held.
-func (c *Direct) hostInfoLocked() *tailcfg.Hostinfo {
-	hi := c.hostinfo.Clone()
-	hi.NetInfo = c.netinfo.Clone()
-	return hi
-}
-
 func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, newURL string, nks tkatype.MarshaledSignature, err error) {
 	c.mu.Lock()
 	persist := c.persist.AsStruct()
@@ -460,7 +427,7 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new
 	serverKey := c.serverKey
 	serverNoiseKey := c.serverNoiseKey
 	authKey, isWrapped, wrappedSig, wrappedKey := decodeWrappedAuthkey(c.authKey, c.logf)
-	hi := c.hostInfoLocked()
+	hi := c.hostinfo
 	backendLogID := hi.BackendLogID
 	expired := !c.expiry.IsZero() && c.expiry.Before(c.clock.Now())
 	c.mu.Unlock()
@@ -849,7 +816,7 @@ func (c *Direct) sendMapRequest(ctx context.Context, isStreaming bool, nu Netmap
 	serverURL := c.serverURL
 	serverKey := c.serverKey
 	serverNoiseKey := c.serverNoiseKey
-	hi := c.hostInfoLocked()
+	hi := c.hostinfo
 	backendLogID := hi.BackendLogID
 	var epStrs []string
 	var eps []netip.AddrPort
diff --git a/ipn/ipnlocal/local.go b/ipn/ipnlocal/local.go
index d78106114..16282c564 100644
--- a/ipn/ipnlocal/local.go
+++ b/ipn/ipnlocal/local.go
@@ -19,6 +19,7 @@ import (
 	"os"
 	"os/user"
 	"path/filepath"
+	"reflect"
 	"runtime"
 	"slices"
 	"sort"
@@ -202,15 +203,13 @@ type LocalBackend struct {
 	// hostinfo is the up-to-date hostinfo, it is only replaced never mutated in
 	// place. This contains all values except for those listed below. To get the
 	// fully populated hostinfo, use b.generateHostinfoForControlLocked().
-	//
-	// TODO(maisem): tailcfg.NetInfo is owned by cc and blended into hostinfo,
-	// we should move it here too.
 	hostinfo tailcfg.HostinfoView
 	// The following values are plugged into a copy of b.hostinfo before it is
 	// sent to control, they are not set on b.hostinfo itself.
 	wantIngress     bool
 	services        views.Slice[tailcfg.Service]
 	pushDeviceToken string
+	netinfo         *tailcfg.NetInfo
 
 	conf           *conffile.Config // latest parsed config, or nil if not in declarative mode
 	pm             *profileManager  // mu guards access
@@ -3122,9 +3121,6 @@ func (b *LocalBackend) peerAPIServicesLocked() (ret []tailcfg.Service) {
 
 // doSetHostinfoFilterServices calls SetHostinfo on the controlclient,
 // possibly after mangling the given hostinfo.
-//
-// TODO(danderson): we shouldn't be mangling hostinfo here after
-// painstakingly constructing it in twelvety other places.
 func (b *LocalBackend) doSetHostinfoFilterServices() {
 	b.mu.Lock()
 	if b.cc == nil {
@@ -3150,6 +3146,7 @@ func (b *LocalBackend) generateHostinfoForControlLocked() *tailcfg.Hostinfo {
 		return nil
 	}
 	hi := b.hostinfo.AsStruct()
+	hi.NetInfo = b.netinfo
 
 	hi.Services = b.peerAPIServicesLocked()
 	if b.shouldUploadServicesLocked() {
@@ -4200,13 +4197,14 @@ func (b *LocalBackend) assertClientLocked() {
 // setNetInfo sets the provided NetInfo on the control client, if any.
 func (b *LocalBackend) setNetInfo(ni *tailcfg.NetInfo) {
 	b.mu.Lock()
-	cc := b.cc
-	b.mu.Unlock()
-
-	if cc == nil {
+	if b.netinfo != nil && ni != nil && reflect.DeepEqual(ni, b.netinfo) {
+		b.mu.Unlock()
 		return
 	}
-	cc.SetNetInfo(ni)
+	b.netinfo = ni.Clone()
+	b.mu.Unlock()
+
+	b.doSetHostinfoFilterServices()
 }
 
 func hasCapability(nm *netmap.NetworkMap, cap tailcfg.NodeCapability) bool {