Holger Hildebrandt | fa07499 | 2020-03-27 15:42:06 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * |
| 3 | * Copyright 2014 gRPC authors. |
| 4 | * |
| 5 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 6 | * you may not use this file except in compliance with the License. |
| 7 | * You may obtain a copy of the License at |
| 8 | * |
| 9 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | * |
| 11 | * Unless required by applicable law or agreed to in writing, software |
| 12 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 14 | * See the License for the specific language governing permissions and |
| 15 | * limitations under the License. |
| 16 | * |
| 17 | */ |
| 18 | |
| 19 | package transport |
| 20 | |
| 21 | import ( |
| 22 | "bytes" |
| 23 | "fmt" |
| 24 | "runtime" |
| 25 | "sync" |
| 26 | "sync/atomic" |
| 27 | |
| 28 | "golang.org/x/net/http2" |
| 29 | "golang.org/x/net/http2/hpack" |
| 30 | ) |
| 31 | |
| 32 | var updateHeaderTblSize = func(e *hpack.Encoder, v uint32) { |
| 33 | e.SetMaxDynamicTableSizeLimit(v) |
| 34 | } |
| 35 | |
| 36 | type itemNode struct { |
| 37 | it interface{} |
| 38 | next *itemNode |
| 39 | } |
| 40 | |
| 41 | type itemList struct { |
| 42 | head *itemNode |
| 43 | tail *itemNode |
| 44 | } |
| 45 | |
| 46 | func (il *itemList) enqueue(i interface{}) { |
| 47 | n := &itemNode{it: i} |
| 48 | if il.tail == nil { |
| 49 | il.head, il.tail = n, n |
| 50 | return |
| 51 | } |
| 52 | il.tail.next = n |
| 53 | il.tail = n |
| 54 | } |
| 55 | |
| 56 | // peek returns the first item in the list without removing it from the |
| 57 | // list. |
| 58 | func (il *itemList) peek() interface{} { |
| 59 | return il.head.it |
| 60 | } |
| 61 | |
| 62 | func (il *itemList) dequeue() interface{} { |
| 63 | if il.head == nil { |
| 64 | return nil |
| 65 | } |
| 66 | i := il.head.it |
| 67 | il.head = il.head.next |
| 68 | if il.head == nil { |
| 69 | il.tail = nil |
| 70 | } |
| 71 | return i |
| 72 | } |
| 73 | |
| 74 | func (il *itemList) dequeueAll() *itemNode { |
| 75 | h := il.head |
| 76 | il.head, il.tail = nil, nil |
| 77 | return h |
| 78 | } |
| 79 | |
| 80 | func (il *itemList) isEmpty() bool { |
| 81 | return il.head == nil |
| 82 | } |
| 83 | |
| 84 | // The following defines various control items which could flow through |
| 85 | // the control buffer of transport. They represent different aspects of |
| 86 | // control tasks, e.g., flow control, settings, streaming resetting, etc. |
| 87 | |
| 88 | // maxQueuedTransportResponseFrames is the most queued "transport response" |
| 89 | // frames we will buffer before preventing new reads from occurring on the |
| 90 | // transport. These are control frames sent in response to client requests, |
| 91 | // such as RST_STREAM due to bad headers or settings acks. |
| 92 | const maxQueuedTransportResponseFrames = 50 |
| 93 | |
| 94 | type cbItem interface { |
| 95 | isTransportResponseFrame() bool |
| 96 | } |
| 97 | |
| 98 | // registerStream is used to register an incoming stream with loopy writer. |
| 99 | type registerStream struct { |
| 100 | streamID uint32 |
| 101 | wq *writeQuota |
| 102 | } |
| 103 | |
| 104 | func (*registerStream) isTransportResponseFrame() bool { return false } |
| 105 | |
| 106 | // headerFrame is also used to register stream on the client-side. |
| 107 | type headerFrame struct { |
| 108 | streamID uint32 |
| 109 | hf []hpack.HeaderField |
| 110 | endStream bool // Valid on server side. |
| 111 | initStream func(uint32) error // Used only on the client side. |
| 112 | onWrite func() |
| 113 | wq *writeQuota // write quota for the stream created. |
| 114 | cleanup *cleanupStream // Valid on the server side. |
| 115 | onOrphaned func(error) // Valid on client-side |
| 116 | } |
| 117 | |
| 118 | func (h *headerFrame) isTransportResponseFrame() bool { |
| 119 | return h.cleanup != nil && h.cleanup.rst // Results in a RST_STREAM |
| 120 | } |
| 121 | |
| 122 | type cleanupStream struct { |
| 123 | streamID uint32 |
| 124 | rst bool |
| 125 | rstCode http2.ErrCode |
| 126 | onWrite func() |
| 127 | } |
| 128 | |
| 129 | func (c *cleanupStream) isTransportResponseFrame() bool { return c.rst } // Results in a RST_STREAM |
| 130 | |
| 131 | type dataFrame struct { |
| 132 | streamID uint32 |
| 133 | endStream bool |
| 134 | h []byte |
| 135 | d []byte |
| 136 | // onEachWrite is called every time |
| 137 | // a part of d is written out. |
| 138 | onEachWrite func() |
| 139 | } |
| 140 | |
| 141 | func (*dataFrame) isTransportResponseFrame() bool { return false } |
| 142 | |
| 143 | type incomingWindowUpdate struct { |
| 144 | streamID uint32 |
| 145 | increment uint32 |
| 146 | } |
| 147 | |
| 148 | func (*incomingWindowUpdate) isTransportResponseFrame() bool { return false } |
| 149 | |
| 150 | type outgoingWindowUpdate struct { |
| 151 | streamID uint32 |
| 152 | increment uint32 |
| 153 | } |
| 154 | |
| 155 | func (*outgoingWindowUpdate) isTransportResponseFrame() bool { |
| 156 | return false // window updates are throttled by thresholds |
| 157 | } |
| 158 | |
| 159 | type incomingSettings struct { |
| 160 | ss []http2.Setting |
| 161 | } |
| 162 | |
| 163 | func (*incomingSettings) isTransportResponseFrame() bool { return true } // Results in a settings ACK |
| 164 | |
| 165 | type outgoingSettings struct { |
| 166 | ss []http2.Setting |
| 167 | } |
| 168 | |
| 169 | func (*outgoingSettings) isTransportResponseFrame() bool { return false } |
| 170 | |
| 171 | type incomingGoAway struct { |
| 172 | } |
| 173 | |
| 174 | func (*incomingGoAway) isTransportResponseFrame() bool { return false } |
| 175 | |
| 176 | type goAway struct { |
| 177 | code http2.ErrCode |
| 178 | debugData []byte |
| 179 | headsUp bool |
| 180 | closeConn bool |
| 181 | } |
| 182 | |
| 183 | func (*goAway) isTransportResponseFrame() bool { return false } |
| 184 | |
| 185 | type ping struct { |
| 186 | ack bool |
| 187 | data [8]byte |
| 188 | } |
| 189 | |
| 190 | func (*ping) isTransportResponseFrame() bool { return true } |
| 191 | |
| 192 | type outFlowControlSizeRequest struct { |
| 193 | resp chan uint32 |
| 194 | } |
| 195 | |
| 196 | func (*outFlowControlSizeRequest) isTransportResponseFrame() bool { return false } |
| 197 | |
| 198 | type outStreamState int |
| 199 | |
| 200 | const ( |
| 201 | active outStreamState = iota |
| 202 | empty |
| 203 | waitingOnStreamQuota |
| 204 | ) |
| 205 | |
| 206 | type outStream struct { |
| 207 | id uint32 |
| 208 | state outStreamState |
| 209 | itl *itemList |
| 210 | bytesOutStanding int |
| 211 | wq *writeQuota |
| 212 | |
| 213 | next *outStream |
| 214 | prev *outStream |
| 215 | } |
| 216 | |
| 217 | func (s *outStream) deleteSelf() { |
| 218 | if s.prev != nil { |
| 219 | s.prev.next = s.next |
| 220 | } |
| 221 | if s.next != nil { |
| 222 | s.next.prev = s.prev |
| 223 | } |
| 224 | s.next, s.prev = nil, nil |
| 225 | } |
| 226 | |
| 227 | type outStreamList struct { |
| 228 | // Following are sentinel objects that mark the |
| 229 | // beginning and end of the list. They do not |
| 230 | // contain any item lists. All valid objects are |
| 231 | // inserted in between them. |
| 232 | // This is needed so that an outStream object can |
| 233 | // deleteSelf() in O(1) time without knowing which |
| 234 | // list it belongs to. |
| 235 | head *outStream |
| 236 | tail *outStream |
| 237 | } |
| 238 | |
| 239 | func newOutStreamList() *outStreamList { |
| 240 | head, tail := new(outStream), new(outStream) |
| 241 | head.next = tail |
| 242 | tail.prev = head |
| 243 | return &outStreamList{ |
| 244 | head: head, |
| 245 | tail: tail, |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | func (l *outStreamList) enqueue(s *outStream) { |
| 250 | e := l.tail.prev |
| 251 | e.next = s |
| 252 | s.prev = e |
| 253 | s.next = l.tail |
| 254 | l.tail.prev = s |
| 255 | } |
| 256 | |
| 257 | // remove from the beginning of the list. |
| 258 | func (l *outStreamList) dequeue() *outStream { |
| 259 | b := l.head.next |
| 260 | if b == l.tail { |
| 261 | return nil |
| 262 | } |
| 263 | b.deleteSelf() |
| 264 | return b |
| 265 | } |
| 266 | |
| 267 | // controlBuffer is a way to pass information to loopy. |
| 268 | // Information is passed as specific struct types called control frames. |
| 269 | // A control frame not only represents data, messages or headers to be sent out |
| 270 | // but can also be used to instruct loopy to update its internal state. |
| 271 | // It shouldn't be confused with an HTTP2 frame, although some of the control frames |
| 272 | // like dataFrame and headerFrame do go out on wire as HTTP2 frames. |
| 273 | type controlBuffer struct { |
| 274 | ch chan struct{} |
| 275 | done <-chan struct{} |
| 276 | mu sync.Mutex |
| 277 | consumerWaiting bool |
| 278 | list *itemList |
| 279 | err error |
| 280 | |
| 281 | // transportResponseFrames counts the number of queued items that represent |
| 282 | // the response of an action initiated by the peer. trfChan is created |
| 283 | // when transportResponseFrames >= maxQueuedTransportResponseFrames and is |
| 284 | // closed and nilled when transportResponseFrames drops below the |
| 285 | // threshold. Both fields are protected by mu. |
| 286 | transportResponseFrames int |
| 287 | trfChan atomic.Value // *chan struct{} |
| 288 | } |
| 289 | |
| 290 | func newControlBuffer(done <-chan struct{}) *controlBuffer { |
| 291 | return &controlBuffer{ |
| 292 | ch: make(chan struct{}, 1), |
| 293 | list: &itemList{}, |
| 294 | done: done, |
| 295 | } |
| 296 | } |
| 297 | |
| 298 | // throttle blocks if there are too many incomingSettings/cleanupStreams in the |
| 299 | // controlbuf. |
| 300 | func (c *controlBuffer) throttle() { |
| 301 | ch, _ := c.trfChan.Load().(*chan struct{}) |
| 302 | if ch != nil { |
| 303 | select { |
| 304 | case <-*ch: |
| 305 | case <-c.done: |
| 306 | } |
| 307 | } |
| 308 | } |
| 309 | |
| 310 | func (c *controlBuffer) put(it cbItem) error { |
| 311 | _, err := c.executeAndPut(nil, it) |
| 312 | return err |
| 313 | } |
| 314 | |
| 315 | func (c *controlBuffer) executeAndPut(f func(it interface{}) bool, it cbItem) (bool, error) { |
| 316 | var wakeUp bool |
| 317 | c.mu.Lock() |
| 318 | if c.err != nil { |
| 319 | c.mu.Unlock() |
| 320 | return false, c.err |
| 321 | } |
| 322 | if f != nil { |
| 323 | if !f(it) { // f wasn't successful |
| 324 | c.mu.Unlock() |
| 325 | return false, nil |
| 326 | } |
| 327 | } |
| 328 | if c.consumerWaiting { |
| 329 | wakeUp = true |
| 330 | c.consumerWaiting = false |
| 331 | } |
| 332 | c.list.enqueue(it) |
| 333 | if it.isTransportResponseFrame() { |
| 334 | c.transportResponseFrames++ |
| 335 | if c.transportResponseFrames == maxQueuedTransportResponseFrames { |
| 336 | // We are adding the frame that puts us over the threshold; create |
| 337 | // a throttling channel. |
| 338 | ch := make(chan struct{}) |
| 339 | c.trfChan.Store(&ch) |
| 340 | } |
| 341 | } |
| 342 | c.mu.Unlock() |
| 343 | if wakeUp { |
| 344 | select { |
| 345 | case c.ch <- struct{}{}: |
| 346 | default: |
| 347 | } |
| 348 | } |
| 349 | return true, nil |
| 350 | } |
| 351 | |
| 352 | // Note argument f should never be nil. |
| 353 | func (c *controlBuffer) execute(f func(it interface{}) bool, it interface{}) (bool, error) { |
| 354 | c.mu.Lock() |
| 355 | if c.err != nil { |
| 356 | c.mu.Unlock() |
| 357 | return false, c.err |
| 358 | } |
| 359 | if !f(it) { // f wasn't successful |
| 360 | c.mu.Unlock() |
| 361 | return false, nil |
| 362 | } |
| 363 | c.mu.Unlock() |
| 364 | return true, nil |
| 365 | } |
| 366 | |
| 367 | func (c *controlBuffer) get(block bool) (interface{}, error) { |
| 368 | for { |
| 369 | c.mu.Lock() |
| 370 | if c.err != nil { |
| 371 | c.mu.Unlock() |
| 372 | return nil, c.err |
| 373 | } |
| 374 | if !c.list.isEmpty() { |
| 375 | h := c.list.dequeue().(cbItem) |
| 376 | if h.isTransportResponseFrame() { |
| 377 | if c.transportResponseFrames == maxQueuedTransportResponseFrames { |
| 378 | // We are removing the frame that put us over the |
| 379 | // threshold; close and clear the throttling channel. |
| 380 | ch := c.trfChan.Load().(*chan struct{}) |
| 381 | close(*ch) |
| 382 | c.trfChan.Store((*chan struct{})(nil)) |
| 383 | } |
| 384 | c.transportResponseFrames-- |
| 385 | } |
| 386 | c.mu.Unlock() |
| 387 | return h, nil |
| 388 | } |
| 389 | if !block { |
| 390 | c.mu.Unlock() |
| 391 | return nil, nil |
| 392 | } |
| 393 | c.consumerWaiting = true |
| 394 | c.mu.Unlock() |
| 395 | select { |
| 396 | case <-c.ch: |
| 397 | case <-c.done: |
| 398 | c.finish() |
| 399 | return nil, ErrConnClosing |
| 400 | } |
| 401 | } |
| 402 | } |
| 403 | |
| 404 | func (c *controlBuffer) finish() { |
| 405 | c.mu.Lock() |
| 406 | if c.err != nil { |
| 407 | c.mu.Unlock() |
| 408 | return |
| 409 | } |
| 410 | c.err = ErrConnClosing |
| 411 | // There may be headers for streams in the control buffer. |
| 412 | // These streams need to be cleaned out since the transport |
| 413 | // is still not aware of these yet. |
| 414 | for head := c.list.dequeueAll(); head != nil; head = head.next { |
| 415 | hdr, ok := head.it.(*headerFrame) |
| 416 | if !ok { |
| 417 | continue |
| 418 | } |
| 419 | if hdr.onOrphaned != nil { // It will be nil on the server-side. |
| 420 | hdr.onOrphaned(ErrConnClosing) |
| 421 | } |
| 422 | } |
| 423 | c.mu.Unlock() |
| 424 | } |
| 425 | |
| 426 | type side int |
| 427 | |
| 428 | const ( |
| 429 | clientSide side = iota |
| 430 | serverSide |
| 431 | ) |
| 432 | |
| 433 | // Loopy receives frames from the control buffer. |
| 434 | // Each frame is handled individually; most of the work done by loopy goes |
| 435 | // into handling data frames. Loopy maintains a queue of active streams, and each |
| 436 | // stream maintains a queue of data frames; as loopy receives data frames |
| 437 | // it gets added to the queue of the relevant stream. |
| 438 | // Loopy goes over this list of active streams by processing one node every iteration, |
| 439 | // thereby closely resemebling to a round-robin scheduling over all streams. While |
| 440 | // processing a stream, loopy writes out data bytes from this stream capped by the min |
| 441 | // of http2MaxFrameLen, connection-level flow control and stream-level flow control. |
| 442 | type loopyWriter struct { |
| 443 | side side |
| 444 | cbuf *controlBuffer |
| 445 | sendQuota uint32 |
| 446 | oiws uint32 // outbound initial window size. |
| 447 | // estdStreams is map of all established streams that are not cleaned-up yet. |
| 448 | // On client-side, this is all streams whose headers were sent out. |
| 449 | // On server-side, this is all streams whose headers were received. |
| 450 | estdStreams map[uint32]*outStream // Established streams. |
| 451 | // activeStreams is a linked-list of all streams that have data to send and some |
| 452 | // stream-level flow control quota. |
| 453 | // Each of these streams internally have a list of data items(and perhaps trailers |
| 454 | // on the server-side) to be sent out. |
| 455 | activeStreams *outStreamList |
| 456 | framer *framer |
| 457 | hBuf *bytes.Buffer // The buffer for HPACK encoding. |
| 458 | hEnc *hpack.Encoder // HPACK encoder. |
| 459 | bdpEst *bdpEstimator |
| 460 | draining bool |
| 461 | |
| 462 | // Side-specific handlers |
| 463 | ssGoAwayHandler func(*goAway) (bool, error) |
| 464 | } |
| 465 | |
| 466 | func newLoopyWriter(s side, fr *framer, cbuf *controlBuffer, bdpEst *bdpEstimator) *loopyWriter { |
| 467 | var buf bytes.Buffer |
| 468 | l := &loopyWriter{ |
| 469 | side: s, |
| 470 | cbuf: cbuf, |
| 471 | sendQuota: defaultWindowSize, |
| 472 | oiws: defaultWindowSize, |
| 473 | estdStreams: make(map[uint32]*outStream), |
| 474 | activeStreams: newOutStreamList(), |
| 475 | framer: fr, |
| 476 | hBuf: &buf, |
| 477 | hEnc: hpack.NewEncoder(&buf), |
| 478 | bdpEst: bdpEst, |
| 479 | } |
| 480 | return l |
| 481 | } |
| 482 | |
| 483 | const minBatchSize = 1000 |
| 484 | |
| 485 | // run should be run in a separate goroutine. |
| 486 | // It reads control frames from controlBuf and processes them by: |
| 487 | // 1. Updating loopy's internal state, or/and |
| 488 | // 2. Writing out HTTP2 frames on the wire. |
| 489 | // |
| 490 | // Loopy keeps all active streams with data to send in a linked-list. |
| 491 | // All streams in the activeStreams linked-list must have both: |
| 492 | // 1. Data to send, and |
| 493 | // 2. Stream level flow control quota available. |
| 494 | // |
| 495 | // In each iteration of run loop, other than processing the incoming control |
| 496 | // frame, loopy calls processData, which processes one node from the activeStreams linked-list. |
| 497 | // This results in writing of HTTP2 frames into an underlying write buffer. |
| 498 | // When there's no more control frames to read from controlBuf, loopy flushes the write buffer. |
| 499 | // As an optimization, to increase the batch size for each flush, loopy yields the processor, once |
| 500 | // if the batch size is too low to give stream goroutines a chance to fill it up. |
| 501 | func (l *loopyWriter) run() (err error) { |
| 502 | defer func() { |
| 503 | if err == ErrConnClosing { |
| 504 | // Don't log ErrConnClosing as error since it happens |
| 505 | // 1. When the connection is closed by some other known issue. |
| 506 | // 2. User closed the connection. |
| 507 | // 3. A graceful close of connection. |
| 508 | infof("transport: loopyWriter.run returning. %v", err) |
| 509 | err = nil |
| 510 | } |
| 511 | }() |
| 512 | for { |
| 513 | it, err := l.cbuf.get(true) |
| 514 | if err != nil { |
| 515 | return err |
| 516 | } |
| 517 | if err = l.handle(it); err != nil { |
| 518 | return err |
| 519 | } |
| 520 | if _, err = l.processData(); err != nil { |
| 521 | return err |
| 522 | } |
| 523 | gosched := true |
| 524 | hasdata: |
| 525 | for { |
| 526 | it, err := l.cbuf.get(false) |
| 527 | if err != nil { |
| 528 | return err |
| 529 | } |
| 530 | if it != nil { |
| 531 | if err = l.handle(it); err != nil { |
| 532 | return err |
| 533 | } |
| 534 | if _, err = l.processData(); err != nil { |
| 535 | return err |
| 536 | } |
| 537 | continue hasdata |
| 538 | } |
| 539 | isEmpty, err := l.processData() |
| 540 | if err != nil { |
| 541 | return err |
| 542 | } |
| 543 | if !isEmpty { |
| 544 | continue hasdata |
| 545 | } |
| 546 | if gosched { |
| 547 | gosched = false |
| 548 | if l.framer.writer.offset < minBatchSize { |
| 549 | runtime.Gosched() |
| 550 | continue hasdata |
| 551 | } |
| 552 | } |
| 553 | l.framer.writer.Flush() |
| 554 | break hasdata |
| 555 | |
| 556 | } |
| 557 | } |
| 558 | } |
| 559 | |
| 560 | func (l *loopyWriter) outgoingWindowUpdateHandler(w *outgoingWindowUpdate) error { |
| 561 | return l.framer.fr.WriteWindowUpdate(w.streamID, w.increment) |
| 562 | } |
| 563 | |
| 564 | func (l *loopyWriter) incomingWindowUpdateHandler(w *incomingWindowUpdate) error { |
| 565 | // Otherwise update the quota. |
| 566 | if w.streamID == 0 { |
| 567 | l.sendQuota += w.increment |
| 568 | return nil |
| 569 | } |
| 570 | // Find the stream and update it. |
| 571 | if str, ok := l.estdStreams[w.streamID]; ok { |
| 572 | str.bytesOutStanding -= int(w.increment) |
| 573 | if strQuota := int(l.oiws) - str.bytesOutStanding; strQuota > 0 && str.state == waitingOnStreamQuota { |
| 574 | str.state = active |
| 575 | l.activeStreams.enqueue(str) |
| 576 | return nil |
| 577 | } |
| 578 | } |
| 579 | return nil |
| 580 | } |
| 581 | |
| 582 | func (l *loopyWriter) outgoingSettingsHandler(s *outgoingSettings) error { |
| 583 | return l.framer.fr.WriteSettings(s.ss...) |
| 584 | } |
| 585 | |
| 586 | func (l *loopyWriter) incomingSettingsHandler(s *incomingSettings) error { |
| 587 | if err := l.applySettings(s.ss); err != nil { |
| 588 | return err |
| 589 | } |
| 590 | return l.framer.fr.WriteSettingsAck() |
| 591 | } |
| 592 | |
| 593 | func (l *loopyWriter) registerStreamHandler(h *registerStream) error { |
| 594 | str := &outStream{ |
| 595 | id: h.streamID, |
| 596 | state: empty, |
| 597 | itl: &itemList{}, |
| 598 | wq: h.wq, |
| 599 | } |
| 600 | l.estdStreams[h.streamID] = str |
| 601 | return nil |
| 602 | } |
| 603 | |
| 604 | func (l *loopyWriter) headerHandler(h *headerFrame) error { |
| 605 | if l.side == serverSide { |
| 606 | str, ok := l.estdStreams[h.streamID] |
| 607 | if !ok { |
| 608 | warningf("transport: loopy doesn't recognize the stream: %d", h.streamID) |
| 609 | return nil |
| 610 | } |
| 611 | // Case 1.A: Server is responding back with headers. |
| 612 | if !h.endStream { |
| 613 | return l.writeHeader(h.streamID, h.endStream, h.hf, h.onWrite) |
| 614 | } |
| 615 | // else: Case 1.B: Server wants to close stream. |
| 616 | |
| 617 | if str.state != empty { // either active or waiting on stream quota. |
| 618 | // add it str's list of items. |
| 619 | str.itl.enqueue(h) |
| 620 | return nil |
| 621 | } |
| 622 | if err := l.writeHeader(h.streamID, h.endStream, h.hf, h.onWrite); err != nil { |
| 623 | return err |
| 624 | } |
| 625 | return l.cleanupStreamHandler(h.cleanup) |
| 626 | } |
| 627 | // Case 2: Client wants to originate stream. |
| 628 | str := &outStream{ |
| 629 | id: h.streamID, |
| 630 | state: empty, |
| 631 | itl: &itemList{}, |
| 632 | wq: h.wq, |
| 633 | } |
| 634 | str.itl.enqueue(h) |
| 635 | return l.originateStream(str) |
| 636 | } |
| 637 | |
| 638 | func (l *loopyWriter) originateStream(str *outStream) error { |
| 639 | hdr := str.itl.dequeue().(*headerFrame) |
| 640 | if err := hdr.initStream(str.id); err != nil { |
| 641 | if err == ErrConnClosing { |
| 642 | return err |
| 643 | } |
| 644 | // Other errors(errStreamDrain) need not close transport. |
| 645 | return nil |
| 646 | } |
| 647 | if err := l.writeHeader(str.id, hdr.endStream, hdr.hf, hdr.onWrite); err != nil { |
| 648 | return err |
| 649 | } |
| 650 | l.estdStreams[str.id] = str |
| 651 | return nil |
| 652 | } |
| 653 | |
| 654 | func (l *loopyWriter) writeHeader(streamID uint32, endStream bool, hf []hpack.HeaderField, onWrite func()) error { |
| 655 | if onWrite != nil { |
| 656 | onWrite() |
| 657 | } |
| 658 | l.hBuf.Reset() |
| 659 | for _, f := range hf { |
| 660 | if err := l.hEnc.WriteField(f); err != nil { |
| 661 | warningf("transport: loopyWriter.writeHeader encountered error while encoding headers:", err) |
| 662 | } |
| 663 | } |
| 664 | var ( |
| 665 | err error |
| 666 | endHeaders, first bool |
| 667 | ) |
| 668 | first = true |
| 669 | for !endHeaders { |
| 670 | size := l.hBuf.Len() |
| 671 | if size > http2MaxFrameLen { |
| 672 | size = http2MaxFrameLen |
| 673 | } else { |
| 674 | endHeaders = true |
| 675 | } |
| 676 | if first { |
| 677 | first = false |
| 678 | err = l.framer.fr.WriteHeaders(http2.HeadersFrameParam{ |
| 679 | StreamID: streamID, |
| 680 | BlockFragment: l.hBuf.Next(size), |
| 681 | EndStream: endStream, |
| 682 | EndHeaders: endHeaders, |
| 683 | }) |
| 684 | } else { |
| 685 | err = l.framer.fr.WriteContinuation( |
| 686 | streamID, |
| 687 | endHeaders, |
| 688 | l.hBuf.Next(size), |
| 689 | ) |
| 690 | } |
| 691 | if err != nil { |
| 692 | return err |
| 693 | } |
| 694 | } |
| 695 | return nil |
| 696 | } |
| 697 | |
| 698 | func (l *loopyWriter) preprocessData(df *dataFrame) error { |
| 699 | str, ok := l.estdStreams[df.streamID] |
| 700 | if !ok { |
| 701 | return nil |
| 702 | } |
| 703 | // If we got data for a stream it means that |
| 704 | // stream was originated and the headers were sent out. |
| 705 | str.itl.enqueue(df) |
| 706 | if str.state == empty { |
| 707 | str.state = active |
| 708 | l.activeStreams.enqueue(str) |
| 709 | } |
| 710 | return nil |
| 711 | } |
| 712 | |
| 713 | func (l *loopyWriter) pingHandler(p *ping) error { |
| 714 | if !p.ack { |
| 715 | l.bdpEst.timesnap(p.data) |
| 716 | } |
| 717 | return l.framer.fr.WritePing(p.ack, p.data) |
| 718 | |
| 719 | } |
| 720 | |
| 721 | func (l *loopyWriter) outFlowControlSizeRequestHandler(o *outFlowControlSizeRequest) error { |
| 722 | o.resp <- l.sendQuota |
| 723 | return nil |
| 724 | } |
| 725 | |
| 726 | func (l *loopyWriter) cleanupStreamHandler(c *cleanupStream) error { |
| 727 | c.onWrite() |
| 728 | if str, ok := l.estdStreams[c.streamID]; ok { |
| 729 | // On the server side it could be a trailers-only response or |
| 730 | // a RST_STREAM before stream initialization thus the stream might |
| 731 | // not be established yet. |
| 732 | delete(l.estdStreams, c.streamID) |
| 733 | str.deleteSelf() |
| 734 | } |
| 735 | if c.rst { // If RST_STREAM needs to be sent. |
| 736 | if err := l.framer.fr.WriteRSTStream(c.streamID, c.rstCode); err != nil { |
| 737 | return err |
| 738 | } |
| 739 | } |
| 740 | if l.side == clientSide && l.draining && len(l.estdStreams) == 0 { |
| 741 | return ErrConnClosing |
| 742 | } |
| 743 | return nil |
| 744 | } |
| 745 | |
| 746 | func (l *loopyWriter) incomingGoAwayHandler(*incomingGoAway) error { |
| 747 | if l.side == clientSide { |
| 748 | l.draining = true |
| 749 | if len(l.estdStreams) == 0 { |
| 750 | return ErrConnClosing |
| 751 | } |
| 752 | } |
| 753 | return nil |
| 754 | } |
| 755 | |
| 756 | func (l *loopyWriter) goAwayHandler(g *goAway) error { |
| 757 | // Handling of outgoing GoAway is very specific to side. |
| 758 | if l.ssGoAwayHandler != nil { |
| 759 | draining, err := l.ssGoAwayHandler(g) |
| 760 | if err != nil { |
| 761 | return err |
| 762 | } |
| 763 | l.draining = draining |
| 764 | } |
| 765 | return nil |
| 766 | } |
| 767 | |
| 768 | func (l *loopyWriter) handle(i interface{}) error { |
| 769 | switch i := i.(type) { |
| 770 | case *incomingWindowUpdate: |
| 771 | return l.incomingWindowUpdateHandler(i) |
| 772 | case *outgoingWindowUpdate: |
| 773 | return l.outgoingWindowUpdateHandler(i) |
| 774 | case *incomingSettings: |
| 775 | return l.incomingSettingsHandler(i) |
| 776 | case *outgoingSettings: |
| 777 | return l.outgoingSettingsHandler(i) |
| 778 | case *headerFrame: |
| 779 | return l.headerHandler(i) |
| 780 | case *registerStream: |
| 781 | return l.registerStreamHandler(i) |
| 782 | case *cleanupStream: |
| 783 | return l.cleanupStreamHandler(i) |
| 784 | case *incomingGoAway: |
| 785 | return l.incomingGoAwayHandler(i) |
| 786 | case *dataFrame: |
| 787 | return l.preprocessData(i) |
| 788 | case *ping: |
| 789 | return l.pingHandler(i) |
| 790 | case *goAway: |
| 791 | return l.goAwayHandler(i) |
| 792 | case *outFlowControlSizeRequest: |
| 793 | return l.outFlowControlSizeRequestHandler(i) |
| 794 | default: |
| 795 | return fmt.Errorf("transport: unknown control message type %T", i) |
| 796 | } |
| 797 | } |
| 798 | |
| 799 | func (l *loopyWriter) applySettings(ss []http2.Setting) error { |
| 800 | for _, s := range ss { |
| 801 | switch s.ID { |
| 802 | case http2.SettingInitialWindowSize: |
| 803 | o := l.oiws |
| 804 | l.oiws = s.Val |
| 805 | if o < l.oiws { |
| 806 | // If the new limit is greater make all depleted streams active. |
| 807 | for _, stream := range l.estdStreams { |
| 808 | if stream.state == waitingOnStreamQuota { |
| 809 | stream.state = active |
| 810 | l.activeStreams.enqueue(stream) |
| 811 | } |
| 812 | } |
| 813 | } |
| 814 | case http2.SettingHeaderTableSize: |
| 815 | updateHeaderTblSize(l.hEnc, s.Val) |
| 816 | } |
| 817 | } |
| 818 | return nil |
| 819 | } |
| 820 | |
| 821 | // processData removes the first stream from active streams, writes out at most 16KB |
| 822 | // of its data and then puts it at the end of activeStreams if there's still more data |
| 823 | // to be sent and stream has some stream-level flow control. |
| 824 | func (l *loopyWriter) processData() (bool, error) { |
| 825 | if l.sendQuota == 0 { |
| 826 | return true, nil |
| 827 | } |
| 828 | str := l.activeStreams.dequeue() // Remove the first stream. |
| 829 | if str == nil { |
| 830 | return true, nil |
| 831 | } |
| 832 | dataItem := str.itl.peek().(*dataFrame) // Peek at the first data item this stream. |
| 833 | // A data item is represented by a dataFrame, since it later translates into |
| 834 | // multiple HTTP2 data frames. |
| 835 | // Every dataFrame has two buffers; h that keeps grpc-message header and d that is acutal data. |
| 836 | // As an optimization to keep wire traffic low, data from d is copied to h to make as big as the |
| 837 | // maximum possilbe HTTP2 frame size. |
| 838 | |
| 839 | if len(dataItem.h) == 0 && len(dataItem.d) == 0 { // Empty data frame |
| 840 | // Client sends out empty data frame with endStream = true |
| 841 | if err := l.framer.fr.WriteData(dataItem.streamID, dataItem.endStream, nil); err != nil { |
| 842 | return false, err |
| 843 | } |
| 844 | str.itl.dequeue() // remove the empty data item from stream |
| 845 | if str.itl.isEmpty() { |
| 846 | str.state = empty |
| 847 | } else if trailer, ok := str.itl.peek().(*headerFrame); ok { // the next item is trailers. |
| 848 | if err := l.writeHeader(trailer.streamID, trailer.endStream, trailer.hf, trailer.onWrite); err != nil { |
| 849 | return false, err |
| 850 | } |
| 851 | if err := l.cleanupStreamHandler(trailer.cleanup); err != nil { |
| 852 | return false, nil |
| 853 | } |
| 854 | } else { |
| 855 | l.activeStreams.enqueue(str) |
| 856 | } |
| 857 | return false, nil |
| 858 | } |
| 859 | var ( |
| 860 | idx int |
| 861 | buf []byte |
| 862 | ) |
| 863 | if len(dataItem.h) != 0 { // data header has not been written out yet. |
| 864 | buf = dataItem.h |
| 865 | } else { |
| 866 | idx = 1 |
| 867 | buf = dataItem.d |
| 868 | } |
| 869 | size := http2MaxFrameLen |
| 870 | if len(buf) < size { |
| 871 | size = len(buf) |
| 872 | } |
| 873 | if strQuota := int(l.oiws) - str.bytesOutStanding; strQuota <= 0 { // stream-level flow control. |
| 874 | str.state = waitingOnStreamQuota |
| 875 | return false, nil |
| 876 | } else if strQuota < size { |
| 877 | size = strQuota |
| 878 | } |
| 879 | |
| 880 | if l.sendQuota < uint32(size) { // connection-level flow control. |
| 881 | size = int(l.sendQuota) |
| 882 | } |
| 883 | // Now that outgoing flow controls are checked we can replenish str's write quota |
| 884 | str.wq.replenish(size) |
| 885 | var endStream bool |
| 886 | // If this is the last data message on this stream and all of it can be written in this iteration. |
| 887 | if dataItem.endStream && size == len(buf) { |
| 888 | // buf contains either data or it contains header but data is empty. |
| 889 | if idx == 1 || len(dataItem.d) == 0 { |
| 890 | endStream = true |
| 891 | } |
| 892 | } |
| 893 | if dataItem.onEachWrite != nil { |
| 894 | dataItem.onEachWrite() |
| 895 | } |
| 896 | if err := l.framer.fr.WriteData(dataItem.streamID, endStream, buf[:size]); err != nil { |
| 897 | return false, err |
| 898 | } |
| 899 | buf = buf[size:] |
| 900 | str.bytesOutStanding += size |
| 901 | l.sendQuota -= uint32(size) |
| 902 | if idx == 0 { |
| 903 | dataItem.h = buf |
| 904 | } else { |
| 905 | dataItem.d = buf |
| 906 | } |
| 907 | |
| 908 | if len(dataItem.h) == 0 && len(dataItem.d) == 0 { // All the data from that message was written out. |
| 909 | str.itl.dequeue() |
| 910 | } |
| 911 | if str.itl.isEmpty() { |
| 912 | str.state = empty |
| 913 | } else if trailer, ok := str.itl.peek().(*headerFrame); ok { // The next item is trailers. |
| 914 | if err := l.writeHeader(trailer.streamID, trailer.endStream, trailer.hf, trailer.onWrite); err != nil { |
| 915 | return false, err |
| 916 | } |
| 917 | if err := l.cleanupStreamHandler(trailer.cleanup); err != nil { |
| 918 | return false, err |
| 919 | } |
| 920 | } else if int(l.oiws)-str.bytesOutStanding <= 0 { // Ran out of stream quota. |
| 921 | str.state = waitingOnStreamQuota |
| 922 | } else { // Otherwise add it back to the list of active streams. |
| 923 | l.activeStreams.enqueue(str) |
| 924 | } |
| 925 | return false, nil |
| 926 | } |