{ipn/ipnlocal, taildrop}: move put logic to taildrop (#9680)

Cleaning up taildrop logic for sending files.

Updates tailscale/corp#14772

Signed-off-by: Rhea Ghosh <rhea@tailscale.com>
Co-authored-by: Joe Tsai <joetsai@digital-static.net>

ipn/ipnlocal/local.go

@@ -239,7 +239,6 @@ type LocalBackend struct {
 	peerAPIServer    *peerAPIServer // or nil
 	peerAPIListeners []*peerAPIListener
 	loginFlags       controlclient.LoginFlags
-	incomingFiles    map[*incomingFile]bool
 	fileWaiters      set.HandleSet[context.CancelFunc] // of wake-up funcs
 	notifyWatchers   set.HandleSet[*watchSession]
 	lastStatusTime   time.Time // status.AsOf value of the last processed status update
@@ -2213,10 +2212,7 @@ func (b *LocalBackend) sendFileNotify() {
 	// Make sure we always set n.IncomingFiles non-nil so it gets encoded
 	// in JSON to clients. They distinguish between empty and non-nil
 	// to know whether a Notify should be able about files.
-	n.IncomingFiles = make([]ipn.PartialFile, 0)
+	n.IncomingFiles = apiSrv.taildrop.IncomingFiles()
-	for f := range b.incomingFiles {
-		n.IncomingFiles = append(n.IncomingFiles, f.PartialFile())
-	}
 	b.mu.Unlock()
 
 	sort.Slice(n.IncomingFiles, func(i, j int) bool {
@@ -4590,19 +4586,6 @@ func (b *LocalBackend) SetDNS(ctx context.Context, name, value string) error {
 	return cc.SetDNS(ctx, req)
 }
 
-func (b *LocalBackend) registerIncomingFile(inf *incomingFile, active bool) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	if b.incomingFiles == nil {
-		b.incomingFiles = make(map[*incomingFile]bool)
-	}
-	if active {
-		b.incomingFiles[inf] = true
-	} else {
-		delete(b.incomingFiles, inf)
-	}
-}
-
 func peerAPIPorts(peer tailcfg.NodeView) (p4, p6 uint16) {
 	svcs := peer.Hostinfo().Services()
 	for i := range svcs.LenIter() {

ipn/ipnlocal/peerapi.go

@@ -15,7 +15,6 @@ import (
 	"net"
 	"net/http"
 	"net/netip"
-	"net/url"
 	"os"
 	"runtime"
 	"slices"
@@ -39,10 +38,8 @@ import (
 	"tailscale.com/net/sockstats"
 	"tailscale.com/tailcfg"
 	"tailscale.com/taildrop"
-	"tailscale.com/tstime"
 	"tailscale.com/types/views"
 	"tailscale.com/util/clientmetric"
-	"tailscale.com/version/distro"
 	"tailscale.com/wgengine/filter"
 )
 
@@ -586,64 +583,6 @@ func (h *peerAPIHandler) handleServeSockStats(w http.ResponseWriter, r *http.Req
 	fmt.Fprintln(w, "</pre>")
 }
 
-type incomingFile struct {
-	clock tstime.Clock
-
-	name           string // "foo.jpg"
-	started        time.Time
-	size           int64     // or -1 if unknown; never 0
-	w              io.Writer // underlying writer
-	sendFileNotify func()    // called when done
-	partialPath    string    // non-empty in direct mode
-
-	mu         sync.Mutex
-	copied     int64
-	done       bool
-	lastNotify time.Time
-}
-
-func (f *incomingFile) markAndNotifyDone() {
-	f.mu.Lock()
-	f.done = true
-	f.mu.Unlock()
-	f.sendFileNotify()
-}
-
-func (f *incomingFile) Write(p []byte) (n int, err error) {
-	n, err = f.w.Write(p)
-
-	var needNotify bool
-	defer func() {
-		if needNotify {
-			f.sendFileNotify()
-		}
-	}()
-	if n > 0 {
-		f.mu.Lock()
-		defer f.mu.Unlock()
-		f.copied += int64(n)
-		now := f.clock.Now()
-		if f.lastNotify.IsZero() || now.Sub(f.lastNotify) > time.Second {
-			f.lastNotify = now
-			needNotify = true
-		}
-	}
-	return n, err
-}
-
-func (f *incomingFile) PartialFile() ipn.PartialFile {
-	f.mu.Lock()
-	defer f.mu.Unlock()
-	return ipn.PartialFile{
-		Name:         f.name,
-		Started:      f.started,
-		DeclaredSize: f.size,
-		Received:     f.copied,
-		PartialPath:  f.partialPath,
-		Done:         f.done,
-	}
-}
-
 // canPutFile reports whether h can put a file ("Taildrop") to this node.
 func (h *peerAPIHandler) canPutFile() bool {
 	if h.peerNode.UnsignedPeerAPIOnly() {
@@ -687,10 +626,6 @@ func (h *peerAPIHandler) peerHasCap(wantCap tailcfg.PeerCapability) bool {
 }
 
 func (h *peerAPIHandler) handlePeerPut(w http.ResponseWriter, r *http.Request) {
-	if !envknob.CanTaildrop() {
-		http.Error(w, "Taildrop disabled on device", http.StatusForbidden)
-		return
-	}
 	if !h.canPutFile() {
 		http.Error(w, "Taildrop access denied", http.StatusForbidden)
 		return
@@ -699,117 +634,12 @@ func (h *peerAPIHandler) handlePeerPut(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "file sharing not enabled by Tailscale admin", http.StatusForbidden)
 		return
 	}
-	if r.Method != "PUT" {
-		http.Error(w, "expected method PUT", http.StatusMethodNotAllowed)
-		return
-	}
-	if mayDeref(h.ps.taildrop).RootDir == "" {
-		http.Error(w, taildrop.ErrNoTaildrop.Error(), http.StatusInternalServerError)
-		return
-	}
-	if distro.Get() == distro.Unraid && !h.ps.taildrop.DirectFileMode {
-		http.Error(w, "Taildrop folder not configured or accessible", http.StatusInternalServerError)
-		return
-	}
-	rawPath := r.URL.EscapedPath()
-	suffix, ok := strings.CutPrefix(rawPath, "/v0/put/")
-	if !ok {
-		http.Error(w, "misconfigured internals", 500)
-		return
-	}
-	if suffix == "" {
-		http.Error(w, "empty filename", 400)
-		return
-	}
-	if strings.Contains(suffix, "/") {
-		http.Error(w, "directories not supported", 400)
-		return
-	}
-	baseName, err := url.PathUnescape(suffix)
-	if err != nil {
-		http.Error(w, "bad path encoding", 400)
-		return
-	}
-	dstFile, ok := h.ps.taildrop.DiskPath(baseName)
-	if !ok {
-		http.Error(w, "bad filename", 400)
-		return
-	}
 	t0 := h.ps.b.clock.Now()
-	// TODO(bradfitz): prevent same filename being sent by two peers at once
+	n, ok := h.ps.taildrop.HandlePut(w, r)
-
+	if ok {
-	// prevent same filename being sent twice
+		d := h.ps.b.clock.Since(t0).Round(time.Second / 10)
-	if _, err := os.Stat(dstFile); err == nil {
+		h.logf("got put of %s in %v from %v/%v", approxSize(n), d, h.remoteAddr.Addr(), h.peerNode.ComputedName)
-		http.Error(w, "file exists", http.StatusConflict)
-		return
 	}
-
-	partialFile := dstFile + taildrop.PartialSuffix
-	f, err := os.Create(partialFile)
-	if err != nil {
-		h.logf("put Create error: %v", taildrop.RedactErr(err))
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	var success bool
-	defer func() {
-		if !success {
-			os.Remove(partialFile)
-		}
-	}()
-	var finalSize int64
-	var inFile *incomingFile
-	if r.ContentLength != 0 {
-		inFile = &incomingFile{
-			clock:          h.ps.b.clock,
-			name:           baseName,
-			started:        h.ps.b.clock.Now(),
-			size:           r.ContentLength,
-			w:              f,
-			sendFileNotify: h.ps.b.sendFileNotify,
-		}
-		if h.ps.taildrop.DirectFileMode {
-			inFile.partialPath = partialFile
-		}
-		h.ps.b.registerIncomingFile(inFile, true)
-		defer h.ps.b.registerIncomingFile(inFile, false)
-		n, err := io.Copy(inFile, r.Body)
-		if err != nil {
-			err = taildrop.RedactErr(err)
-			f.Close()
-			h.logf("put Copy error: %v", err)
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
-		}
-		finalSize = n
-	}
-	if err := taildrop.RedactErr(f.Close()); err != nil {
-		h.logf("put Close error: %v", err)
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	if h.ps.taildrop.DirectFileMode && !h.ps.taildrop.DirectFileDoFinalRename {
-		if inFile != nil { // non-zero length; TODO: notify even for zero length
-			inFile.markAndNotifyDone()
-		}
-	} else {
-		if err := os.Rename(partialFile, dstFile); err != nil {
-			err = taildrop.RedactErr(err)
-			h.logf("put final rename: %v", err)
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
-		}
-	}
-
-	d := h.ps.b.clock.Since(t0).Round(time.Second / 10)
-	h.logf("got put of %s in %v from %v/%v", approxSize(finalSize), d, h.remoteAddr.Addr(), h.peerNode.ComputedName)
-
-	// TODO: set modtime
-	// TODO: some real response
-	success = true
-	io.WriteString(w, "{}\n")
-	h.ps.taildrop.KnownEmpty.Store(false)
-	h.ps.b.sendFileNotify()
 }
 
 func approxSize(n int64) string {

ipn/ipnlocal/peerapi_test.go

@@ -15,7 +15,6 @@ import (
 	"net/netip"
 	"os"
 	"path/filepath"
-	"runtime"
 	"strings"
 	"testing"
 
@@ -494,7 +493,10 @@ func TestHandlePeerAPI(t *testing.T) {
 			if !tt.omitRoot {
 				rootDir = t.TempDir()
 				if e.ph.ps.taildrop == nil {
-					e.ph.ps.taildrop = &taildrop.Handler{}
+					e.ph.ps.taildrop = &taildrop.Handler{
+						Logf:  e.logBuf.Logf,
+						Clock: &tstest.Clock{},
+					}
 				}
 				e.ph.ps.taildrop.RootDir = rootDir
 			}
@@ -579,92 +581,6 @@ func TestFileDeleteRace(t *testing.T) {
 	}
 }
 
-// Tests "foo.jpg.deleted" marks (for Windows).
-func TestDeletedMarkers(t *testing.T) {
-	dir := t.TempDir()
-	ps := &peerAPIServer{
-		b: &LocalBackend{
-			logf:           t.Logf,
-			capFileSharing: true,
-		},
-		taildrop: &taildrop.Handler{
-			RootDir: dir,
-		},
-	}
-
-	nothingWaiting := func() {
-		t.Helper()
-		ps.taildrop.KnownEmpty.Store(false)
-		if ps.taildrop.HasFilesWaiting() {
-			t.Fatal("unexpected files waiting")
-		}
-	}
-	touch := func(base string) {
-		t.Helper()
-		if err := taildrop.TouchFile(filepath.Join(dir, base)); err != nil {
-			t.Fatal(err)
-		}
-	}
-	wantEmptyTempDir := func() {
-		t.Helper()
-		if fis, err := os.ReadDir(dir); err != nil {
-			t.Fatal(err)
-		} else if len(fis) > 0 && runtime.GOOS != "windows" {
-			for _, fi := range fis {
-				t.Errorf("unexpected file in tempdir: %q", fi.Name())
-			}
-		}
-	}
-
-	nothingWaiting()
-	wantEmptyTempDir()
-
-	touch("foo.jpg.deleted")
-	nothingWaiting()
-	wantEmptyTempDir()
-
-	touch("foo.jpg.deleted")
-	touch("foo.jpg")
-	nothingWaiting()
-	wantEmptyTempDir()
-
-	touch("foo.jpg.deleted")
-	touch("foo.jpg")
-	wf, err := ps.taildrop.WaitingFiles()
-	if err != nil {
-		t.Fatal(err)
-	}
-	if len(wf) != 0 {
-		t.Fatalf("WaitingFiles = %d; want 0", len(wf))
-	}
-	wantEmptyTempDir()
-
-	touch("foo.jpg.deleted")
-	touch("foo.jpg")
-	if rc, _, err := ps.taildrop.OpenFile("foo.jpg"); err == nil {
-		rc.Close()
-		t.Fatal("unexpected foo.jpg open")
-	}
-	wantEmptyTempDir()
-
-	// And verify basics still work in non-deleted cases.
-	touch("foo.jpg")
-	touch("bar.jpg.deleted")
-	if wf, err := ps.taildrop.WaitingFiles(); err != nil {
-		t.Error(err)
-	} else if len(wf) != 1 {
-		t.Errorf("WaitingFiles = %d; want 1", len(wf))
-	} else if wf[0].Name != "foo.jpg" {
-		t.Errorf("unexpected waiting file %+v", wf[0])
-	}
-	if rc, _, err := ps.taildrop.OpenFile("foo.jpg"); err != nil {
-		t.Fatal(err)
-	} else {
-		rc.Close()
-	}
-
-}
-
 func TestPeerAPIReplyToDNSQueries(t *testing.T) {
 	var h peerAPIHandler
 

taildrop/retrieve.go

@@ -25,7 +25,7 @@ func (s *Handler) HasFilesWaiting() bool {
 	if s == nil || s.RootDir == "" || s.DirectFileMode {
 		return false
 	}
-	if s.KnownEmpty.Load() {
+	if s.knownEmpty.Load() {
 		// Optimization: this is usually empty, so avoid opening
 		// the directory and checking. We can't cache the actual
 		// has-files-or-not values as the macOS/iOS client might
@@ -66,7 +66,7 @@ func (s *Handler) HasFilesWaiting() bool {
 			}
 		}
 		if err == io.EOF {
-			s.KnownEmpty.Store(true)
+			s.knownEmpty.Store(true)
 		}
 		if err != nil {
 			break

taildrop/send.go

@@ -0,0 +1,182 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package taildrop
+
+import (
+	"io"
+	"net/http"
+	"net/url"
+	"os"
+	"strings"
+	"sync"
+	"time"
+
+	"tailscale.com/envknob"
+	"tailscale.com/tstime"
+	"tailscale.com/version/distro"
+)
+
+type incomingFile struct {
+	clock tstime.Clock
+
+	name           string // "foo.jpg"
+	started        time.Time
+	size           int64     // or -1 if unknown; never 0
+	w              io.Writer // underlying writer
+	sendFileNotify func()    // called when done
+	partialPath    string    // non-empty in direct mode
+
+	mu         sync.Mutex
+	copied     int64
+	done       bool
+	lastNotify time.Time
+}
+
+func (f *incomingFile) markAndNotifyDone() {
+	f.mu.Lock()
+	f.done = true
+	f.mu.Unlock()
+	f.sendFileNotify()
+}
+
+func (f *incomingFile) Write(p []byte) (n int, err error) {
+	n, err = f.w.Write(p)
+
+	var needNotify bool
+	defer func() {
+		if needNotify {
+			f.sendFileNotify()
+		}
+	}()
+	if n > 0 {
+		f.mu.Lock()
+		defer f.mu.Unlock()
+		f.copied += int64(n)
+		now := f.clock.Now()
+		if f.lastNotify.IsZero() || now.Sub(f.lastNotify) > time.Second {
+			f.lastNotify = now
+			needNotify = true
+		}
+	}
+	return n, err
+}
+
+// HandlePut receives a file.
+// It returns the number of bytes received and whether it was received successfully.
+func (h *Handler) HandlePut(w http.ResponseWriter, r *http.Request) (finalSize int64, success bool) {
+	if !envknob.CanTaildrop() {
+		http.Error(w, "Taildrop disabled on device", http.StatusForbidden)
+		return finalSize, success
+	}
+	if r.Method != "PUT" {
+		http.Error(w, "expected method PUT", http.StatusMethodNotAllowed)
+		return finalSize, success
+	}
+	if h == nil || h.RootDir == "" {
+		http.Error(w, ErrNoTaildrop.Error(), http.StatusInternalServerError)
+		return finalSize, success
+	}
+	if distro.Get() == distro.Unraid && !h.DirectFileMode {
+		http.Error(w, "Taildrop folder not configured or accessible", http.StatusInternalServerError)
+		return finalSize, success
+	}
+	rawPath := r.URL.EscapedPath()
+	suffix, ok := strings.CutPrefix(rawPath, "/v0/put/")
+	if !ok {
+		http.Error(w, "misconfigured internals", http.StatusInternalServerError)
+		return finalSize, success
+	}
+	if suffix == "" {
+		http.Error(w, "empty filename", http.StatusBadRequest)
+		return finalSize, success
+	}
+	if strings.Contains(suffix, "/") {
+		http.Error(w, "directories not supported", http.StatusBadRequest)
+		return finalSize, success
+	}
+	baseName, err := url.PathUnescape(suffix)
+	if err != nil {
+		http.Error(w, "bad path encoding", http.StatusBadRequest)
+		return finalSize, success
+	}
+	dstFile, ok := h.DiskPath(baseName)
+	if !ok {
+		http.Error(w, "bad filename", 400)
+		return finalSize, success
+	}
+	// TODO(bradfitz): prevent same filename being sent by two peers at once
+
+	// prevent same filename being sent twice
+	if _, err := os.Stat(dstFile); err == nil {
+		http.Error(w, "file exists", http.StatusConflict)
+		return finalSize, success
+	}
+
+	partialFile := dstFile + PartialSuffix
+	f, err := os.Create(partialFile)
+	if err != nil {
+		h.Logf("put Create error: %v", RedactErr(err))
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return finalSize, success
+	}
+	defer func() {
+		if !success {
+			os.Remove(partialFile)
+		}
+	}()
+	var inFile *incomingFile
+	sendFileNotify := h.SendFileNotify
+	if sendFileNotify == nil {
+		sendFileNotify = func() {} // avoid nil panics below
+	}
+	if r.ContentLength != 0 {
+		inFile = &incomingFile{
+			clock:          h.Clock,
+			name:           baseName,
+			started:        h.Clock.Now(),
+			size:           r.ContentLength,
+			w:              f,
+			sendFileNotify: sendFileNotify,
+		}
+		if h.DirectFileMode {
+			inFile.partialPath = partialFile
+		}
+		h.incomingFiles.Store(inFile, struct{}{})
+		defer h.incomingFiles.Delete(inFile)
+		n, err := io.Copy(inFile, r.Body)
+		if err != nil {
+			err = RedactErr(err)
+			f.Close()
+			h.Logf("put Copy error: %v", err)
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return finalSize, success
+		}
+		finalSize = n
+	}
+	if err := RedactErr(f.Close()); err != nil {
+		h.Logf("put Close error: %v", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return finalSize, success
+	}
+	if h.DirectFileMode && !h.DirectFileDoFinalRename {
+		if inFile != nil { // non-zero length; TODO: notify even for zero length
+			inFile.markAndNotifyDone()
+		}
+	} else {
+		if err := os.Rename(partialFile, dstFile); err != nil {
+			err = RedactErr(err)
+			h.Logf("put final rename: %v", err)
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return finalSize, success
+		}
+	}
+
+	// TODO: set modtime
+	// TODO: some real response
+	success = true
+	io.WriteString(w, "{}\n")
+	h.knownEmpty.Store(false)
+	sendFileNotify()
+	return finalSize, success
+}

taildrop/taildrop.go

@@ -15,6 +15,8 @@ import (
 	"unicode"
 	"unicode/utf8"
 
+	"tailscale.com/ipn"
+	"tailscale.com/syncs"
 	"tailscale.com/tstime"
 	"tailscale.com/types/logger"
 	"tailscale.com/util/multierr"
@@ -41,7 +43,14 @@ type Handler struct {
 	// it's received.
 	DirectFileDoFinalRename bool
 
-	KnownEmpty atomic.Bool
+	// SendFileNotify is called periodically while a file is actively
+	// receiving the contents for the file. There is a final call
+	// to the function when reception completes.
+	SendFileNotify func()
+
+	knownEmpty atomic.Bool
+
+	incomingFiles syncs.Map[*incomingFile, struct{}]
 }
 
 var (
@@ -113,6 +122,27 @@ func (s *Handler) DiskPath(baseName string) (fullPath string, ok bool) {
 	return filepath.Join(s.RootDir, baseName), true
 }
 
+func (s *Handler) IncomingFiles() []ipn.PartialFile {
+	// Make sure we always set n.IncomingFiles non-nil so it gets encoded
+	// in JSON to clients. They distinguish between empty and non-nil
+	// to know whether a Notify should be able about files.
+	files := make([]ipn.PartialFile, 0)
+	s.incomingFiles.Range(func(f *incomingFile, _ struct{}) bool {
+		f.mu.Lock()
+		defer f.mu.Unlock()
+		files = append(files, ipn.PartialFile{
+			Name:         f.name,
+			Started:      f.started,
+			DeclaredSize: f.size,
+			Received:     f.copied,
+			PartialPath:  f.partialPath,
+			Done:         f.done,
+		})
+		return true
+	})
+	return files
+}
+
 type redactedErr struct {
 	msg   string
 	inner error

taildrop/taildrop_test.go

@@ -0,0 +1,88 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package taildrop
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+)
+
+// Tests "foo.jpg.deleted" marks (for Windows).
+func TestDeletedMarkers(t *testing.T) {
+	dir := t.TempDir()
+	h := &Handler{RootDir: dir}
+
+	nothingWaiting := func() {
+		t.Helper()
+		h.knownEmpty.Store(false)
+		if h.HasFilesWaiting() {
+			t.Fatal("unexpected files waiting")
+		}
+	}
+	touch := func(base string) {
+		t.Helper()
+		if err := TouchFile(filepath.Join(dir, base)); err != nil {
+			t.Fatal(err)
+		}
+	}
+	wantEmptyTempDir := func() {
+		t.Helper()
+		if fis, err := os.ReadDir(dir); err != nil {
+			t.Fatal(err)
+		} else if len(fis) > 0 && runtime.GOOS != "windows" {
+			for _, fi := range fis {
+				t.Errorf("unexpected file in tempdir: %q", fi.Name())
+			}
+		}
+	}
+
+	nothingWaiting()
+	wantEmptyTempDir()
+
+	touch("foo.jpg.deleted")
+	nothingWaiting()
+	wantEmptyTempDir()
+
+	touch("foo.jpg.deleted")
+	touch("foo.jpg")
+	nothingWaiting()
+	wantEmptyTempDir()
+
+	touch("foo.jpg.deleted")
+	touch("foo.jpg")
+	wf, err := h.WaitingFiles()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(wf) != 0 {
+		t.Fatalf("WaitingFiles = %d; want 0", len(wf))
+	}
+	wantEmptyTempDir()
+
+	touch("foo.jpg.deleted")
+	touch("foo.jpg")
+	if rc, _, err := h.OpenFile("foo.jpg"); err == nil {
+		rc.Close()
+		t.Fatal("unexpected foo.jpg open")
+	}
+	wantEmptyTempDir()
+
+	// And verify basics still work in non-deleted cases.
+	touch("foo.jpg")
+	touch("bar.jpg.deleted")
+	if wf, err := h.WaitingFiles(); err != nil {
+		t.Error(err)
+	} else if len(wf) != 1 {
+		t.Errorf("WaitingFiles = %d; want 1", len(wf))
+	} else if wf[0].Name != "foo.jpg" {
+		t.Errorf("unexpected waiting file %+v", wf[0])
+	}
+	if rc, _, err := h.OpenFile("foo.jpg"); err != nil {
+		t.Fatal(err)
+	} else {
+		rc.Close()
+	}
+}