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puellanivispuellanivis
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Merge pull request #584 from peterverraedt/configure-maxTxPacket
Add WithMaxTxPacket server option
2 parents 06342e8 + c1f47ba commit 5494656

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5 files changed

+78
-40
lines changed

5 files changed

+78
-40
lines changed

‎packet.go

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -823,7 +823,7 @@ func (p *sshFxpReadPacket) UnmarshalBinary(b []byte) error {
823823
// So, we need: uint32(length) + byte(type) + uint32(id) + uint32(data_length)
824824
const dataHeaderLen = 4 + 1 + 4 + 4
825825

826-
func (p *sshFxpReadPacket) getDataSlice(alloc *allocator, orderID uint32) []byte {
826+
func (p *sshFxpReadPacket) getDataSlice(alloc *allocator, orderID uint32, maxTxPacket uint32) []byte {
827827
dataLen := p.Len
828828
if dataLen > maxTxPacket {
829829
dataLen = maxTxPacket

‎request-server.go

Lines changed: 25 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@ import (
1010
"sync"
1111
)
1212

13-
var maxTxPacket uint32 = 1 << 15
13+
const defaultMaxTxPacket uint32 = 1 << 15
1414

1515
// Handlers contains the 4 SFTP server request handlers.
1616
type Handlers struct {
@@ -28,6 +28,7 @@ type RequestServer struct {
2828
pktMgr *packetManager
2929

3030
startDirectory string
31+
maxTxPacket uint32
3132

3233
mu sync.RWMutex
3334
handleCount int
@@ -57,6 +58,22 @@ func WithStartDirectory(startDirectory string) RequestServerOption {
5758
}
5859
}
5960

61+
// WithRSMaxTxPacket sets the maximum size of the payload returned to the client,
62+
// measured in bytes. The default value is 32768 bytes, and this option
63+
// can only be used to increase it. Setting this option to a larger value
64+
// should be safe, because the client decides the size of the requested payload.
65+
//
66+
// The default maximum packet size is 32768 bytes.
67+
func WithRSMaxTxPacket(size uint32) RequestServerOption {
68+
return func(rs *RequestServer) {
69+
if size < defaultMaxTxPacket {
70+
return
71+
}
72+
73+
rs.maxTxPacket = size
74+
}
75+
}
76+
6077
// NewRequestServer creates/allocates/returns new RequestServer.
6178
// Normally there will be one server per user-session.
6279
func NewRequestServer(rwc io.ReadWriteCloser, h Handlers, options ...RequestServerOption) *RequestServer {
@@ -73,6 +90,7 @@ func NewRequestServer(rwc io.ReadWriteCloser, h Handlers, options ...RequestServ
7390
pktMgr: newPktMgr(svrConn),
7491

7592
startDirectory: "/",
93+
maxTxPacket: defaultMaxTxPacket,
7694

7795
openRequests: make(map[string]*Request),
7896
}
@@ -260,7 +278,7 @@ func (rs *RequestServer) packetWorker(ctx context.Context, pktChan chan orderedR
260278
Method: "Stat",
261279
Filepath: cleanPathWithBase(rs.startDirectory, request.Filepath),
262280
}
263-
rpkt = request.call(rs.Handlers, pkt, rs.pktMgr.alloc, orderID)
281+
rpkt = request.call(rs.Handlers, pkt, rs.pktMgr.alloc, orderID, rs.maxTxPacket)
264282
}
265283
case *sshFxpFsetstatPacket:
266284
handle := pkt.getHandle()
@@ -272,32 +290,32 @@ func (rs *RequestServer) packetWorker(ctx context.Context, pktChan chan orderedR
272290
Method: "Setstat",
273291
Filepath: cleanPathWithBase(rs.startDirectory, request.Filepath),
274292
}
275-
rpkt = request.call(rs.Handlers, pkt, rs.pktMgr.alloc, orderID)
293+
rpkt = request.call(rs.Handlers, pkt, rs.pktMgr.alloc, orderID, rs.maxTxPacket)
276294
}
277295
case *sshFxpExtendedPacketPosixRename:
278296
request := &Request{
279297
Method: "PosixRename",
280298
Filepath: cleanPathWithBase(rs.startDirectory, pkt.Oldpath),
281299
Target: cleanPathWithBase(rs.startDirectory, pkt.Newpath),
282300
}
283-
rpkt = request.call(rs.Handlers, pkt, rs.pktMgr.alloc, orderID)
301+
rpkt = request.call(rs.Handlers, pkt, rs.pktMgr.alloc, orderID, rs.maxTxPacket)
284302
case *sshFxpExtendedPacketStatVFS:
285303
request := &Request{
286304
Method: "StatVFS",
287305
Filepath: cleanPathWithBase(rs.startDirectory, pkt.Path),
288306
}
289-
rpkt = request.call(rs.Handlers, pkt, rs.pktMgr.alloc, orderID)
307+
rpkt = request.call(rs.Handlers, pkt, rs.pktMgr.alloc, orderID, rs.maxTxPacket)
290308
case hasHandle:
291309
handle := pkt.getHandle()
292310
request, ok := rs.getRequest(handle)
293311
if !ok {
294312
rpkt = statusFromError(pkt.id(), EBADF)
295313
} else {
296-
rpkt = request.call(rs.Handlers, pkt, rs.pktMgr.alloc, orderID)
314+
rpkt = request.call(rs.Handlers, pkt, rs.pktMgr.alloc, orderID, rs.maxTxPacket)
297315
}
298316
case hasPath:
299317
request := requestFromPacket(ctx, pkt, rs.startDirectory)
300-
rpkt = request.call(rs.Handlers, pkt, rs.pktMgr.alloc, orderID)
318+
rpkt = request.call(rs.Handlers, pkt, rs.pktMgr.alloc, orderID, rs.maxTxPacket)
301319
request.close()
302320
default:
303321
rpkt = statusFromError(pkt.id(), ErrSSHFxOpUnsupported)

‎request.go

Lines changed: 12 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -300,14 +300,14 @@ func (r *Request) transferError(err error) {
300300
}
301301

302302
// called from worker to handle packet/request
303-
func (r *Request) call(handlers Handlers, pkt requestPacket, alloc *allocator, orderID uint32) responsePacket {
303+
func (r *Request) call(handlers Handlers, pkt requestPacket, alloc *allocator, orderID uint32, maxTxPacket uint32) responsePacket {
304304
switch r.Method {
305305
case "Get":
306-
return fileget(handlers.FileGet, r, pkt, alloc, orderID)
306+
return fileget(handlers.FileGet, r, pkt, alloc, orderID, maxTxPacket)
307307
case "Put":
308-
return fileput(handlers.FilePut, r, pkt, alloc, orderID)
308+
return fileput(handlers.FilePut, r, pkt, alloc, orderID, maxTxPacket)
309309
case "Open":
310-
return fileputget(handlers.FilePut, r, pkt, alloc, orderID)
310+
return fileputget(handlers.FilePut, r, pkt, alloc, orderID, maxTxPacket)
311311
case "Setstat", "Rename", "Rmdir", "Mkdir", "Link", "Symlink", "Remove", "PosixRename", "StatVFS":
312312
return filecmd(handlers.FileCmd, r, pkt)
313313
case "List":
@@ -392,13 +392,13 @@ func (r *Request) opendir(h Handlers, pkt requestPacket) responsePacket {
392392
}
393393

394394
// wrap FileReader handler
395-
func fileget(h FileReader, r *Request, pkt requestPacket, alloc *allocator, orderID uint32) responsePacket {
395+
func fileget(h FileReader, r *Request, pkt requestPacket, alloc *allocator, orderID uint32, maxTxPacket uint32) responsePacket {
396396
rd := r.getReaderAt()
397397
if rd == nil {
398398
return statusFromError(pkt.id(), errors.New("unexpected read packet"))
399399
}
400400

401-
data, offset, _ := packetData(pkt, alloc, orderID)
401+
data, offset, _ := packetData(pkt, alloc, orderID, maxTxPacket)
402402

403403
n, err := rd.ReadAt(data, offset)
404404
// only return EOF error if no data left to read
@@ -414,28 +414,28 @@ func fileget(h FileReader, r *Request, pkt requestPacket, alloc *allocator, orde
414414
}
415415

416416
// wrap FileWriter handler
417-
func fileput(h FileWriter, r *Request, pkt requestPacket, alloc *allocator, orderID uint32) responsePacket {
417+
func fileput(h FileWriter, r *Request, pkt requestPacket, alloc *allocator, orderID uint32, maxTxPacket uint32) responsePacket {
418418
wr := r.getWriterAt()
419419
if wr == nil {
420420
return statusFromError(pkt.id(), errors.New("unexpected write packet"))
421421
}
422422

423-
data, offset, _ := packetData(pkt, alloc, orderID)
423+
data, offset, _ := packetData(pkt, alloc, orderID, maxTxPacket)
424424

425425
_, err := wr.WriteAt(data, offset)
426426
return statusFromError(pkt.id(), err)
427427
}
428428

429429
// wrap OpenFileWriter handler
430-
func fileputget(h FileWriter, r *Request, pkt requestPacket, alloc *allocator, orderID uint32) responsePacket {
430+
func fileputget(h FileWriter, r *Request, pkt requestPacket, alloc *allocator, orderID uint32, maxTxPacket uint32) responsePacket {
431431
rw := r.getWriterAtReaderAt()
432432
if rw == nil {
433433
return statusFromError(pkt.id(), errors.New("unexpected write and read packet"))
434434
}
435435

436436
switch p := pkt.(type) {
437437
case *sshFxpReadPacket:
438-
data, offset := p.getDataSlice(alloc, orderID), int64(p.Offset)
438+
data, offset := p.getDataSlice(alloc, orderID, maxTxPacket), int64(p.Offset)
439439

440440
n, err := rw.ReadAt(data, offset)
441441
// only return EOF error if no data left to read
@@ -461,10 +461,10 @@ func fileputget(h FileWriter, r *Request, pkt requestPacket, alloc *allocator, o
461461
}
462462

463463
// file data for additional read/write packets
464-
func packetData(p requestPacket, alloc *allocator, orderID uint32) (data []byte, offset int64, length uint32) {
464+
func packetData(p requestPacket, alloc *allocator, orderID uint32, maxTxPacket uint32) (data []byte, offset int64, length uint32) {
465465
switch p := p.(type) {
466466
case *sshFxpReadPacket:
467-
return p.getDataSlice(alloc, orderID), int64(p.Offset), p.Len
467+
return p.getDataSlice(alloc, orderID, maxTxPacket), int64(p.Offset), p.Len
468468
case *sshFxpWritePacket:
469469
return p.Data, int64(p.Offset), p.Length
470470
}

‎request_test.go

Lines changed: 11 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -149,7 +149,7 @@ func TestRequestGet(t *testing.T) {
149149
for i, txt := range []string{"file-", "data."} {
150150
pkt := &sshFxpReadPacket{ID: uint32(i), Handle: "a",
151151
Offset: uint64(i * 5), Len: 5}
152-
rpkt := request.call(handlers, pkt, nil, 0)
152+
rpkt := request.call(handlers, pkt, nil, 0, defaultMaxTxPacket)
153153
dpkt := rpkt.(*sshFxpDataPacket)
154154
assert.Equal(t, dpkt.id(), uint32(i))
155155
assert.Equal(t, string(dpkt.Data), txt)
@@ -162,7 +162,7 @@ func TestRequestCustomError(t *testing.T) {
162162
pkt := fakePacket{myid: 1}
163163
cmdErr := errors.New("stat not supported")
164164
handlers.returnError(cmdErr)
165-
rpkt := request.call(handlers, pkt, nil, 0)
165+
rpkt := request.call(handlers, pkt, nil, 0, defaultMaxTxPacket)
166166
assert.Equal(t, rpkt, statusFromError(pkt.myid, cmdErr))
167167
}
168168

@@ -173,11 +173,11 @@ func TestRequestPut(t *testing.T) {
173173
request.state.writerAt, _ = handlers.FilePut.Filewrite(request)
174174
pkt := &sshFxpWritePacket{ID: 0, Handle: "a", Offset: 0, Length: 5,
175175
Data: []byte("file-")}
176-
rpkt := request.call(handlers, pkt, nil, 0)
176+
rpkt := request.call(handlers, pkt, nil, 0, defaultMaxTxPacket)
177177
checkOkStatus(t, rpkt)
178178
pkt = &sshFxpWritePacket{ID: 1, Handle: "a", Offset: 5, Length: 5,
179179
Data: []byte("data.")}
180-
rpkt = request.call(handlers, pkt, nil, 0)
180+
rpkt = request.call(handlers, pkt, nil, 0, defaultMaxTxPacket)
181181
checkOkStatus(t, rpkt)
182182
assert.Equal(t, "file-data.", handlers.getOutString())
183183
}
@@ -186,19 +186,19 @@ func TestRequestCmdr(t *testing.T) {
186186
handlers := newTestHandlers()
187187
request := testRequest("Mkdir")
188188
pkt := fakePacket{myid: 1}
189-
rpkt := request.call(handlers, pkt, nil, 0)
189+
rpkt := request.call(handlers, pkt, nil, 0, defaultMaxTxPacket)
190190
checkOkStatus(t, rpkt)
191191

192192
handlers.returnError(errTest)
193-
rpkt = request.call(handlers, pkt, nil, 0)
193+
rpkt = request.call(handlers, pkt, nil, 0, defaultMaxTxPacket)
194194
assert.Equal(t, rpkt, statusFromError(pkt.myid, errTest))
195195
}
196196

197197
func TestRequestInfoStat(t *testing.T) {
198198
handlers := newTestHandlers()
199199
request := testRequest("Stat")
200200
pkt := fakePacket{myid: 1}
201-
rpkt := request.call(handlers, pkt, nil, 0)
201+
rpkt := request.call(handlers, pkt, nil, 0, defaultMaxTxPacket)
202202
spkt, ok := rpkt.(*sshFxpStatResponse)
203203
assert.True(t, ok)
204204
assert.Equal(t, spkt.info.Name(), "request_test.go")
@@ -215,13 +215,13 @@ func TestRequestInfoList(t *testing.T) {
215215
assert.Equal(t, hpkt.Handle, "1")
216216
}
217217
pkt = fakePacket{myid: 2}
218-
request.call(handlers, pkt, nil, 0)
218+
request.call(handlers, pkt, nil, 0, defaultMaxTxPacket)
219219
}
220220
func TestRequestInfoReadlink(t *testing.T) {
221221
handlers := newTestHandlers()
222222
request := testRequest("Readlink")
223223
pkt := fakePacket{myid: 1}
224-
rpkt := request.call(handlers, pkt, nil, 0)
224+
rpkt := request.call(handlers, pkt, nil, 0, defaultMaxTxPacket)
225225
npkt, ok := rpkt.(*sshFxpNamePacket)
226226
if assert.True(t, ok) {
227227
assert.IsType(t, &sshFxpNameAttr{}, npkt.NameAttrs[0])
@@ -234,7 +234,7 @@ func TestOpendirHandleReuse(t *testing.T) {
234234
request := testRequest("Stat")
235235
request.handle = "1"
236236
pkt := fakePacket{myid: 1}
237-
rpkt := request.call(handlers, pkt, nil, 0)
237+
rpkt := request.call(handlers, pkt, nil, 0, defaultMaxTxPacket)
238238
assert.IsType(t, &sshFxpStatResponse{}, rpkt)
239239

240240
request.Method = "List"
@@ -244,6 +244,6 @@ func TestOpendirHandleReuse(t *testing.T) {
244244
hpkt := rpkt.(*sshFxpHandlePacket)
245245
assert.Equal(t, hpkt.Handle, "1")
246246
}
247-
rpkt = request.call(handlers, pkt, nil, 0)
247+
rpkt = request.call(handlers, pkt, nil, 0, defaultMaxTxPacket)
248248
assert.IsType(t, &sshFxpNamePacket{}, rpkt)
249249
}

‎server.go

Lines changed: 29 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -34,6 +34,7 @@ type Server struct {
3434
openFilesLock sync.RWMutex
3535
handleCount int
3636
workDir string
37+
maxTxPacket uint32
3738
}
3839

3940
func (svr *Server) nextHandle(f *os.File) string {
@@ -86,6 +87,7 @@ func NewServer(rwc io.ReadWriteCloser, options ...ServerOption) (*Server, error)
8687
debugStream: ioutil.Discard,
8788
pktMgr: newPktMgr(svrConn),
8889
openFiles: make(map[string]*os.File),
90+
maxTxPacket: defaultMaxTxPacket,
8991
}
9092

9193
for _, o := range options {
@@ -139,6 +141,24 @@ func WithServerWorkingDirectory(workDir string) ServerOption {
139141
}
140142
}
141143

144+
// WithMaxTxPacket sets the maximum size of the payload returned to the client,
145+
// measured in bytes. The default value is 32768 bytes, and this option
146+
// can only be used to increase it. Setting this option to a larger value
147+
// should be safe, because the client decides the size of the requested payload.
148+
//
149+
// The default maximum packet size is 32768 bytes.
150+
func WithMaxTxPacket(size uint32) ServerOption {
151+
return func(s *Server) error {
152+
if size < defaultMaxTxPacket {
153+
return errors.New("size must be greater than or equal to 32768")
154+
}
155+
156+
s.maxTxPacket = size
157+
158+
return nil
159+
}
160+
}
161+
142162
type rxPacket struct {
143163
pktType fxp
144164
pktBytes []byte
@@ -287,7 +307,7 @@ func handlePacket(s *Server, p orderedRequest) error {
287307
f, ok := s.getHandle(p.Handle)
288308
if ok {
289309
err = nil
290-
data := p.getDataSlice(s.pktMgr.alloc, orderID)
310+
data := p.getDataSlice(s.pktMgr.alloc, orderID, s.maxTxPacket)
291311
n, _err := f.ReadAt(data, int64(p.Offset))
292312
if _err != nil && (_err != io.EOF || n == 0) {
293313
err = _err
@@ -513,16 +533,16 @@ func (p *sshFxpSetstatPacket) respond(svr *Server) responsePacket {
513533

514534
fs, err := p.unmarshalFileStat(p.Flags)
515535

516-
if err == nil && (p.Flags & sshFileXferAttrSize) != 0 {
536+
if err == nil && (p.Flags&sshFileXferAttrSize) != 0 {
517537
err = os.Truncate(path, int64(fs.Size))
518538
}
519-
if err == nil && (p.Flags & sshFileXferAttrPermissions) != 0 {
539+
if err == nil && (p.Flags&sshFileXferAttrPermissions) != 0 {
520540
err = os.Chmod(path, fs.FileMode())
521541
}
522-
if err == nil && (p.Flags & sshFileXferAttrUIDGID) != 0 {
542+
if err == nil && (p.Flags&sshFileXferAttrUIDGID) != 0 {
523543
err = os.Chown(path, int(fs.UID), int(fs.GID))
524544
}
525-
if err == nil && (p.Flags & sshFileXferAttrACmodTime) != 0 {
545+
if err == nil && (p.Flags&sshFileXferAttrACmodTime) != 0 {
526546
err = os.Chtimes(path, fs.AccessTime(), fs.ModTime())
527547
}
528548

@@ -541,16 +561,16 @@ func (p *sshFxpFsetstatPacket) respond(svr *Server) responsePacket {
541561

542562
fs, err := p.unmarshalFileStat(p.Flags)
543563

544-
if err == nil && (p.Flags & sshFileXferAttrSize) != 0 {
564+
if err == nil && (p.Flags&sshFileXferAttrSize) != 0 {
545565
err = f.Truncate(int64(fs.Size))
546566
}
547-
if err == nil && (p.Flags & sshFileXferAttrPermissions) != 0 {
567+
if err == nil && (p.Flags&sshFileXferAttrPermissions) != 0 {
548568
err = f.Chmod(fs.FileMode())
549569
}
550-
if err == nil && (p.Flags & sshFileXferAttrUIDGID) != 0 {
570+
if err == nil && (p.Flags&sshFileXferAttrUIDGID) != 0 {
551571
err = f.Chown(int(fs.UID), int(fs.GID))
552572
}
553-
if err == nil && (p.Flags & sshFileXferAttrACmodTime) != 0 {
573+
if err == nil && (p.Flags&sshFileXferAttrACmodTime) != 0 {
554574
type chtimer interface {
555575
Chtimes(atime, mtime time.Time) error
556576
}

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