ipn/{ipnlocal,ipnstate,localapi}: add localapi endpoints for client self-update (#10188)

* ipn/{ipnlocal,ipnstate,localapi}: add localapi endpoints for client self-update

Updates #10187.

Signed-off-by: Naman Sood <mail@nsood.in>

* depaware

Updates #10187.

Signed-off-by: Naman Sood <mail@nsood.in>

* address review feedback

Signed-off-by: Naman Sood <mail@nsood.in>

---------

Signed-off-by: Naman Sood <mail@nsood.in>

ipn/ipnstate/ipnstate.go

@@ -22,6 +22,7 @@ import (
 	"tailscale.com/types/ptr"
 	"tailscale.com/types/views"
 	"tailscale.com/util/dnsname"
+	"tailscale.com/version"
 )
 
 //go:generate go run tailscale.com/cmd/cloner  -clonefunc=false -type=TKAFilteredPeer
@@ -710,3 +711,25 @@ type DebugDERPRegionReport struct {
 	Warnings []string
 	Errors   []string
 }
+
+type SelfUpdateStatus string
+
+const (
+	UpdateFinished   SelfUpdateStatus = "UpdateFinished"
+	UpdateInProgress SelfUpdateStatus = "UpdateInProgress"
+	UpdateFailed     SelfUpdateStatus = "UpdateFailed"
+)
+
+type UpdateProgress struct {
+	Status  SelfUpdateStatus `json:"status,omitempty"`
+	Message string           `json:"message,omitempty"`
+	Version string           `json:"version,omitempty"`
+}
+
+func NewUpdateProgress(ps SelfUpdateStatus, msg string) UpdateProgress {
+	return UpdateProgress{
+		Status:  ps,
+		Message: msg,
+		Version: version.Short(),
+	}
+}