tailcfg, localapi: plumb device token to server

Updates tailscale/corp#8940

Signed-off-by: David Crawshaw <crawshaw@tailscale.com>

ipn/localapi/localapi.go

@@ -70,6 +70,7 @@ var handler = map[string]localAPIHandler{
 	"debug-packet-filter-rules":   (*Handler).serveDebugPacketFilterRules,
 	"derpmap":                     (*Handler).serveDERPMap,
 	"dev-set-state-store":         (*Handler).serveDevSetStateStore,
+	"set-push-device-token":       (*Handler).serveSetPushDeviceToken,
 	"dial":                        (*Handler).serveDial,
 	"file-targets":                (*Handler).serveFileTargets,
 	"goroutines":                  (*Handler).serveGoroutines,
@@ -1205,6 +1206,25 @@ func (h *Handler) serveDial(w http.ResponseWriter, r *http.Request) {
 	<-errc
 }
 
+func (h *Handler) serveSetPushDeviceToken(w http.ResponseWriter, r *http.Request) {
+	if !h.PermitWrite {
+		http.Error(w, "set push device token access denied", http.StatusForbidden)
+		return
+	}
+	if r.Method != "POST" {
+		http.Error(w, "unsupported method", http.StatusMethodNotAllowed)
+		return
+	}
+	var params apitype.SetPushDeviceTokenRequest
+	if err := json.NewDecoder(r.Body).Decode(&params); err != nil {
+		http.Error(w, "invalid JSON body", 400)
+		return
+	}
+	hostinfo.SetPushDeviceToken(params.PushDeviceToken)
+	h.b.ResendHostinfoIfNeeded()
+	w.WriteHeader(http.StatusOK)
+}
+
 func (h *Handler) serveUploadClientMetrics(w http.ResponseWriter, r *http.Request) {
 	if r.Method != "POST" {
 		http.Error(w, "unsupported method", http.StatusMethodNotAllowed)

ipn/localapi/localapi_test.go

@@ -4,9 +4,16 @@
 package localapi
 
 import (
+	"bytes"
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/http/httptest"
 	"testing"
 
 	"tailscale.com/client/tailscale/apitype"
+	"tailscale.com/hostinfo"
+	"tailscale.com/ipn/ipnlocal"
 )
 
 func TestValidHost(t *testing.T) {
@@ -32,3 +39,43 @@ func TestValidHost(t *testing.T) {
 		})
 	}
 }
+
+func TestSetPushDeviceToken(t *testing.T) {
+	origValidLocalHost := validLocalHost
+	validLocalHost = true
+	defer func() {
+		validLocalHost = origValidLocalHost
+	}()
+
+	h := &Handler{
+		PermitWrite: true,
+		b:           &ipnlocal.LocalBackend{},
+	}
+	s := httptest.NewServer(h)
+	defer s.Close()
+	c := s.Client()
+
+	want := "my-test-device-token"
+	body, err := json.Marshal(apitype.SetPushDeviceTokenRequest{PushDeviceToken: want})
+	if err != nil {
+		t.Fatal(err)
+	}
+	req, err := http.NewRequest("POST", s.URL+"/localapi/v0/set-push-device-token", bytes.NewReader(body))
+	if err != nil {
+		t.Fatal(err)
+	}
+	res, err := c.Do(req)
+	if err != nil {
+		t.Fatal(err)
+	}
+	body, err = io.ReadAll(res.Body)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if res.StatusCode != 200 {
+		t.Errorf("res.StatusCode=%d, want 200. body: %s", res.StatusCode, body)
+	}
+	if got := hostinfo.New().PushDeviceToken; got != want {
+		t.Errorf("hostinfo.PushDeviceToken=%q, want %q", got, want)
+	}
+}