William Kurkian | ea86948 | 2019-04-09 15:16:11 -0400 | [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 | |
| 27 | "golang.org/x/net/http2" |
| 28 | "golang.org/x/net/http2/hpack" |
| 29 | ) |
| 30 | |
| 31 | var updateHeaderTblSize = func(e *hpack.Encoder, v uint32) { |
| 32 | e.SetMaxDynamicTableSizeLimit(v) |
| 33 | } |
| 34 | |
| 35 | type itemNode struct { |
| 36 | it interface{} |
| 37 | next *itemNode |
| 38 | } |
| 39 | |
| 40 | type itemList struct { |
| 41 | head *itemNode |
| 42 | tail *itemNode |
| 43 | } |
| 44 | |
| 45 | func (il *itemList) enqueue(i interface{}) { |
| 46 | n := &itemNode{it: i} |
| 47 | if il.tail == nil { |
| 48 | il.head, il.tail = n, n |
| 49 | return |
| 50 | } |
| 51 | il.tail.next = n |
| 52 | il.tail = n |
| 53 | } |
| 54 | |
| 55 | // peek returns the first item in the list without removing it from the |
| 56 | // list. |
| 57 | func (il *itemList) peek() interface{} { |
| 58 | return il.head.it |
| 59 | } |
| 60 | |
| 61 | func (il *itemList) dequeue() interface{} { |
| 62 | if il.head == nil { |
| 63 | return nil |
| 64 | } |
| 65 | i := il.head.it |
| 66 | il.head = il.head.next |
| 67 | if il.head == nil { |
| 68 | il.tail = nil |
| 69 | } |
| 70 | return i |
| 71 | } |
| 72 | |
| 73 | func (il *itemList) dequeueAll() *itemNode { |
| 74 | h := il.head |
| 75 | il.head, il.tail = nil, nil |
| 76 | return h |
| 77 | } |
| 78 | |
| 79 | func (il *itemList) isEmpty() bool { |
| 80 | return il.head == nil |
| 81 | } |
| 82 | |
| 83 | // The following defines various control items which could flow through |
| 84 | // the control buffer of transport. They represent different aspects of |
| 85 | // control tasks, e.g., flow control, settings, streaming resetting, etc. |
| 86 | |
| 87 | // registerStream is used to register an incoming stream with loopy writer. |
| 88 | type registerStream struct { |
| 89 | streamID uint32 |
| 90 | wq *writeQuota |
| 91 | } |
| 92 | |
| 93 | // headerFrame is also used to register stream on the client-side. |
| 94 | type headerFrame struct { |
| 95 | streamID uint32 |
| 96 | hf []hpack.HeaderField |
| 97 | endStream bool // Valid on server side. |
| 98 | initStream func(uint32) (bool, error) // Used only on the client side. |
| 99 | onWrite func() |
| 100 | wq *writeQuota // write quota for the stream created. |
| 101 | cleanup *cleanupStream // Valid on the server side. |
| 102 | onOrphaned func(error) // Valid on client-side |
| 103 | } |
| 104 | |
| 105 | type cleanupStream struct { |
| 106 | streamID uint32 |
| 107 | rst bool |
| 108 | rstCode http2.ErrCode |
| 109 | onWrite func() |
| 110 | } |
| 111 | |
| 112 | type dataFrame struct { |
| 113 | streamID uint32 |
| 114 | endStream bool |
| 115 | h []byte |
| 116 | d []byte |
| 117 | // onEachWrite is called every time |
| 118 | // a part of d is written out. |
| 119 | onEachWrite func() |
| 120 | } |
| 121 | |
| 122 | type incomingWindowUpdate struct { |
| 123 | streamID uint32 |
| 124 | increment uint32 |
| 125 | } |
| 126 | |
| 127 | type outgoingWindowUpdate struct { |
| 128 | streamID uint32 |
| 129 | increment uint32 |
| 130 | } |
| 131 | |
| 132 | type incomingSettings struct { |
| 133 | ss []http2.Setting |
| 134 | } |
| 135 | |
| 136 | type outgoingSettings struct { |
| 137 | ss []http2.Setting |
| 138 | } |
| 139 | |
| 140 | type incomingGoAway struct { |
| 141 | } |
| 142 | |
| 143 | type goAway struct { |
| 144 | code http2.ErrCode |
| 145 | debugData []byte |
| 146 | headsUp bool |
| 147 | closeConn bool |
| 148 | } |
| 149 | |
| 150 | type ping struct { |
| 151 | ack bool |
| 152 | data [8]byte |
| 153 | } |
| 154 | |
| 155 | type outFlowControlSizeRequest struct { |
| 156 | resp chan uint32 |
| 157 | } |
| 158 | |
| 159 | type outStreamState int |
| 160 | |
| 161 | const ( |
| 162 | active outStreamState = iota |
| 163 | empty |
| 164 | waitingOnStreamQuota |
| 165 | ) |
| 166 | |
| 167 | type outStream struct { |
| 168 | id uint32 |
| 169 | state outStreamState |
| 170 | itl *itemList |
| 171 | bytesOutStanding int |
| 172 | wq *writeQuota |
| 173 | |
| 174 | next *outStream |
| 175 | prev *outStream |
| 176 | } |
| 177 | |
| 178 | func (s *outStream) deleteSelf() { |
| 179 | if s.prev != nil { |
| 180 | s.prev.next = s.next |
| 181 | } |
| 182 | if s.next != nil { |
| 183 | s.next.prev = s.prev |
| 184 | } |
| 185 | s.next, s.prev = nil, nil |
| 186 | } |
| 187 | |
| 188 | type outStreamList struct { |
| 189 | // Following are sentinel objects that mark the |
| 190 | // beginning and end of the list. They do not |
| 191 | // contain any item lists. All valid objects are |
| 192 | // inserted in between them. |
| 193 | // This is needed so that an outStream object can |
| 194 | // deleteSelf() in O(1) time without knowing which |
| 195 | // list it belongs to. |
| 196 | head *outStream |
| 197 | tail *outStream |
| 198 | } |
| 199 | |
| 200 | func newOutStreamList() *outStreamList { |
| 201 | head, tail := new(outStream), new(outStream) |
| 202 | head.next = tail |
| 203 | tail.prev = head |
| 204 | return &outStreamList{ |
| 205 | head: head, |
| 206 | tail: tail, |
| 207 | } |
| 208 | } |
| 209 | |
| 210 | func (l *outStreamList) enqueue(s *outStream) { |
| 211 | e := l.tail.prev |
| 212 | e.next = s |
| 213 | s.prev = e |
| 214 | s.next = l.tail |
| 215 | l.tail.prev = s |
| 216 | } |
| 217 | |
| 218 | // remove from the beginning of the list. |
| 219 | func (l *outStreamList) dequeue() *outStream { |
| 220 | b := l.head.next |
| 221 | if b == l.tail { |
| 222 | return nil |
| 223 | } |
| 224 | b.deleteSelf() |
| 225 | return b |
| 226 | } |
| 227 | |
| 228 | // controlBuffer is a way to pass information to loopy. |
| 229 | // Information is passed as specific struct types called control frames. |
| 230 | // A control frame not only represents data, messages or headers to be sent out |
| 231 | // but can also be used to instruct loopy to update its internal state. |
| 232 | // It shouldn't be confused with an HTTP2 frame, although some of the control frames |
| 233 | // like dataFrame and headerFrame do go out on wire as HTTP2 frames. |
| 234 | type controlBuffer struct { |
| 235 | ch chan struct{} |
| 236 | done <-chan struct{} |
| 237 | mu sync.Mutex |
| 238 | consumerWaiting bool |
| 239 | list *itemList |
| 240 | err error |
| 241 | } |
| 242 | |
| 243 | func newControlBuffer(done <-chan struct{}) *controlBuffer { |
| 244 | return &controlBuffer{ |
| 245 | ch: make(chan struct{}, 1), |
| 246 | list: &itemList{}, |
| 247 | done: done, |
| 248 | } |
| 249 | } |
| 250 | |
| 251 | func (c *controlBuffer) put(it interface{}) error { |
| 252 | _, err := c.executeAndPut(nil, it) |
| 253 | return err |
| 254 | } |
| 255 | |
| 256 | func (c *controlBuffer) executeAndPut(f func(it interface{}) bool, it interface{}) (bool, error) { |
| 257 | var wakeUp bool |
| 258 | c.mu.Lock() |
| 259 | if c.err != nil { |
| 260 | c.mu.Unlock() |
| 261 | return false, c.err |
| 262 | } |
| 263 | if f != nil { |
| 264 | if !f(it) { // f wasn't successful |
| 265 | c.mu.Unlock() |
| 266 | return false, nil |
| 267 | } |
| 268 | } |
| 269 | if c.consumerWaiting { |
| 270 | wakeUp = true |
| 271 | c.consumerWaiting = false |
| 272 | } |
| 273 | c.list.enqueue(it) |
| 274 | c.mu.Unlock() |
| 275 | if wakeUp { |
| 276 | select { |
| 277 | case c.ch <- struct{}{}: |
| 278 | default: |
| 279 | } |
| 280 | } |
| 281 | return true, nil |
| 282 | } |
| 283 | |
| 284 | // Note argument f should never be nil. |
| 285 | func (c *controlBuffer) execute(f func(it interface{}) bool, it interface{}) (bool, error) { |
| 286 | c.mu.Lock() |
| 287 | if c.err != nil { |
| 288 | c.mu.Unlock() |
| 289 | return false, c.err |
| 290 | } |
| 291 | if !f(it) { // f wasn't successful |
| 292 | c.mu.Unlock() |
| 293 | return false, nil |
| 294 | } |
| 295 | c.mu.Unlock() |
| 296 | return true, nil |
| 297 | } |
| 298 | |
| 299 | func (c *controlBuffer) get(block bool) (interface{}, error) { |
| 300 | for { |
| 301 | c.mu.Lock() |
| 302 | if c.err != nil { |
| 303 | c.mu.Unlock() |
| 304 | return nil, c.err |
| 305 | } |
| 306 | if !c.list.isEmpty() { |
| 307 | h := c.list.dequeue() |
| 308 | c.mu.Unlock() |
| 309 | return h, nil |
| 310 | } |
| 311 | if !block { |
| 312 | c.mu.Unlock() |
| 313 | return nil, nil |
| 314 | } |
| 315 | c.consumerWaiting = true |
| 316 | c.mu.Unlock() |
| 317 | select { |
| 318 | case <-c.ch: |
| 319 | case <-c.done: |
| 320 | c.finish() |
| 321 | return nil, ErrConnClosing |
| 322 | } |
| 323 | } |
| 324 | } |
| 325 | |
| 326 | func (c *controlBuffer) finish() { |
| 327 | c.mu.Lock() |
| 328 | if c.err != nil { |
| 329 | c.mu.Unlock() |
| 330 | return |
| 331 | } |
| 332 | c.err = ErrConnClosing |
| 333 | // There may be headers for streams in the control buffer. |
| 334 | // These streams need to be cleaned out since the transport |
| 335 | // is still not aware of these yet. |
| 336 | for head := c.list.dequeueAll(); head != nil; head = head.next { |
| 337 | hdr, ok := head.it.(*headerFrame) |
| 338 | if !ok { |
| 339 | continue |
| 340 | } |
| 341 | if hdr.onOrphaned != nil { // It will be nil on the server-side. |
| 342 | hdr.onOrphaned(ErrConnClosing) |
| 343 | } |
| 344 | } |
| 345 | c.mu.Unlock() |
| 346 | } |
| 347 | |
| 348 | type side int |
| 349 | |
| 350 | const ( |
| 351 | clientSide side = iota |
| 352 | serverSide |
| 353 | ) |
| 354 | |
| 355 | // Loopy receives frames from the control buffer. |
| 356 | // Each frame is handled individually; most of the work done by loopy goes |
| 357 | // into handling data frames. Loopy maintains a queue of active streams, and each |
| 358 | // stream maintains a queue of data frames; as loopy receives data frames |
| 359 | // it gets added to the queue of the relevant stream. |
| 360 | // Loopy goes over this list of active streams by processing one node every iteration, |
| 361 | // thereby closely resemebling to a round-robin scheduling over all streams. While |
| 362 | // processing a stream, loopy writes out data bytes from this stream capped by the min |
| 363 | // of http2MaxFrameLen, connection-level flow control and stream-level flow control. |
| 364 | type loopyWriter struct { |
| 365 | side side |
| 366 | cbuf *controlBuffer |
| 367 | sendQuota uint32 |
| 368 | oiws uint32 // outbound initial window size. |
| 369 | // estdStreams is map of all established streams that are not cleaned-up yet. |
| 370 | // On client-side, this is all streams whose headers were sent out. |
| 371 | // On server-side, this is all streams whose headers were received. |
| 372 | estdStreams map[uint32]*outStream // Established streams. |
| 373 | // activeStreams is a linked-list of all streams that have data to send and some |
| 374 | // stream-level flow control quota. |
| 375 | // Each of these streams internally have a list of data items(and perhaps trailers |
| 376 | // on the server-side) to be sent out. |
| 377 | activeStreams *outStreamList |
| 378 | framer *framer |
| 379 | hBuf *bytes.Buffer // The buffer for HPACK encoding. |
| 380 | hEnc *hpack.Encoder // HPACK encoder. |
| 381 | bdpEst *bdpEstimator |
| 382 | draining bool |
| 383 | |
| 384 | // Side-specific handlers |
| 385 | ssGoAwayHandler func(*goAway) (bool, error) |
| 386 | } |
| 387 | |
| 388 | func newLoopyWriter(s side, fr *framer, cbuf *controlBuffer, bdpEst *bdpEstimator) *loopyWriter { |
| 389 | var buf bytes.Buffer |
| 390 | l := &loopyWriter{ |
| 391 | side: s, |
| 392 | cbuf: cbuf, |
| 393 | sendQuota: defaultWindowSize, |
| 394 | oiws: defaultWindowSize, |
| 395 | estdStreams: make(map[uint32]*outStream), |
| 396 | activeStreams: newOutStreamList(), |
| 397 | framer: fr, |
| 398 | hBuf: &buf, |
| 399 | hEnc: hpack.NewEncoder(&buf), |
| 400 | bdpEst: bdpEst, |
| 401 | } |
| 402 | return l |
| 403 | } |
| 404 | |
| 405 | const minBatchSize = 1000 |
| 406 | |
| 407 | // run should be run in a separate goroutine. |
| 408 | // It reads control frames from controlBuf and processes them by: |
| 409 | // 1. Updating loopy's internal state, or/and |
| 410 | // 2. Writing out HTTP2 frames on the wire. |
| 411 | // |
| 412 | // Loopy keeps all active streams with data to send in a linked-list. |
| 413 | // All streams in the activeStreams linked-list must have both: |
| 414 | // 1. Data to send, and |
| 415 | // 2. Stream level flow control quota available. |
| 416 | // |
| 417 | // In each iteration of run loop, other than processing the incoming control |
| 418 | // frame, loopy calls processData, which processes one node from the activeStreams linked-list. |
| 419 | // This results in writing of HTTP2 frames into an underlying write buffer. |
| 420 | // When there's no more control frames to read from controlBuf, loopy flushes the write buffer. |
| 421 | // As an optimization, to increase the batch size for each flush, loopy yields the processor, once |
| 422 | // if the batch size is too low to give stream goroutines a chance to fill it up. |
| 423 | func (l *loopyWriter) run() (err error) { |
| 424 | defer func() { |
| 425 | if err == ErrConnClosing { |
| 426 | // Don't log ErrConnClosing as error since it happens |
| 427 | // 1. When the connection is closed by some other known issue. |
| 428 | // 2. User closed the connection. |
| 429 | // 3. A graceful close of connection. |
| 430 | infof("transport: loopyWriter.run returning. %v", err) |
| 431 | err = nil |
| 432 | } |
| 433 | }() |
| 434 | for { |
| 435 | it, err := l.cbuf.get(true) |
| 436 | if err != nil { |
| 437 | return err |
| 438 | } |
| 439 | if err = l.handle(it); err != nil { |
| 440 | return err |
| 441 | } |
| 442 | if _, err = l.processData(); err != nil { |
| 443 | return err |
| 444 | } |
| 445 | gosched := true |
| 446 | hasdata: |
| 447 | for { |
| 448 | it, err := l.cbuf.get(false) |
| 449 | if err != nil { |
| 450 | return err |
| 451 | } |
| 452 | if it != nil { |
| 453 | if err = l.handle(it); err != nil { |
| 454 | return err |
| 455 | } |
| 456 | if _, err = l.processData(); err != nil { |
| 457 | return err |
| 458 | } |
| 459 | continue hasdata |
| 460 | } |
| 461 | isEmpty, err := l.processData() |
| 462 | if err != nil { |
| 463 | return err |
| 464 | } |
| 465 | if !isEmpty { |
| 466 | continue hasdata |
| 467 | } |
| 468 | if gosched { |
| 469 | gosched = false |
| 470 | if l.framer.writer.offset < minBatchSize { |
| 471 | runtime.Gosched() |
| 472 | continue hasdata |
| 473 | } |
| 474 | } |
| 475 | l.framer.writer.Flush() |
| 476 | break hasdata |
| 477 | |
| 478 | } |
| 479 | } |
| 480 | } |
| 481 | |
| 482 | func (l *loopyWriter) outgoingWindowUpdateHandler(w *outgoingWindowUpdate) error { |
| 483 | return l.framer.fr.WriteWindowUpdate(w.streamID, w.increment) |
| 484 | } |
| 485 | |
| 486 | func (l *loopyWriter) incomingWindowUpdateHandler(w *incomingWindowUpdate) error { |
| 487 | // Otherwise update the quota. |
| 488 | if w.streamID == 0 { |
| 489 | l.sendQuota += w.increment |
| 490 | return nil |
| 491 | } |
| 492 | // Find the stream and update it. |
| 493 | if str, ok := l.estdStreams[w.streamID]; ok { |
| 494 | str.bytesOutStanding -= int(w.increment) |
| 495 | if strQuota := int(l.oiws) - str.bytesOutStanding; strQuota > 0 && str.state == waitingOnStreamQuota { |
| 496 | str.state = active |
| 497 | l.activeStreams.enqueue(str) |
| 498 | return nil |
| 499 | } |
| 500 | } |
| 501 | return nil |
| 502 | } |
| 503 | |
| 504 | func (l *loopyWriter) outgoingSettingsHandler(s *outgoingSettings) error { |
| 505 | return l.framer.fr.WriteSettings(s.ss...) |
| 506 | } |
| 507 | |
| 508 | func (l *loopyWriter) incomingSettingsHandler(s *incomingSettings) error { |
| 509 | if err := l.applySettings(s.ss); err != nil { |
| 510 | return err |
| 511 | } |
| 512 | return l.framer.fr.WriteSettingsAck() |
| 513 | } |
| 514 | |
| 515 | func (l *loopyWriter) registerStreamHandler(h *registerStream) error { |
| 516 | str := &outStream{ |
| 517 | id: h.streamID, |
| 518 | state: empty, |
| 519 | itl: &itemList{}, |
| 520 | wq: h.wq, |
| 521 | } |
| 522 | l.estdStreams[h.streamID] = str |
| 523 | return nil |
| 524 | } |
| 525 | |
| 526 | func (l *loopyWriter) headerHandler(h *headerFrame) error { |
| 527 | if l.side == serverSide { |
| 528 | str, ok := l.estdStreams[h.streamID] |
| 529 | if !ok { |
| 530 | warningf("transport: loopy doesn't recognize the stream: %d", h.streamID) |
| 531 | return nil |
| 532 | } |
| 533 | // Case 1.A: Server is responding back with headers. |
| 534 | if !h.endStream { |
| 535 | return l.writeHeader(h.streamID, h.endStream, h.hf, h.onWrite) |
| 536 | } |
| 537 | // else: Case 1.B: Server wants to close stream. |
| 538 | |
| 539 | if str.state != empty { // either active or waiting on stream quota. |
| 540 | // add it str's list of items. |
| 541 | str.itl.enqueue(h) |
| 542 | return nil |
| 543 | } |
| 544 | if err := l.writeHeader(h.streamID, h.endStream, h.hf, h.onWrite); err != nil { |
| 545 | return err |
| 546 | } |
| 547 | return l.cleanupStreamHandler(h.cleanup) |
| 548 | } |
| 549 | // Case 2: Client wants to originate stream. |
| 550 | str := &outStream{ |
| 551 | id: h.streamID, |
| 552 | state: empty, |
| 553 | itl: &itemList{}, |
| 554 | wq: h.wq, |
| 555 | } |
| 556 | str.itl.enqueue(h) |
| 557 | return l.originateStream(str) |
| 558 | } |
| 559 | |
| 560 | func (l *loopyWriter) originateStream(str *outStream) error { |
| 561 | hdr := str.itl.dequeue().(*headerFrame) |
| 562 | sendPing, err := hdr.initStream(str.id) |
| 563 | if err != nil { |
| 564 | if err == ErrConnClosing { |
| 565 | return err |
| 566 | } |
| 567 | // Other errors(errStreamDrain) need not close transport. |
| 568 | return nil |
| 569 | } |
| 570 | if err = l.writeHeader(str.id, hdr.endStream, hdr.hf, hdr.onWrite); err != nil { |
| 571 | return err |
| 572 | } |
| 573 | l.estdStreams[str.id] = str |
| 574 | if sendPing { |
| 575 | return l.pingHandler(&ping{data: [8]byte{}}) |
| 576 | } |
| 577 | return nil |
| 578 | } |
| 579 | |
| 580 | func (l *loopyWriter) writeHeader(streamID uint32, endStream bool, hf []hpack.HeaderField, onWrite func()) error { |
| 581 | if onWrite != nil { |
| 582 | onWrite() |
| 583 | } |
| 584 | l.hBuf.Reset() |
| 585 | for _, f := range hf { |
| 586 | if err := l.hEnc.WriteField(f); err != nil { |
| 587 | warningf("transport: loopyWriter.writeHeader encountered error while encoding headers:", err) |
| 588 | } |
| 589 | } |
| 590 | var ( |
| 591 | err error |
| 592 | endHeaders, first bool |
| 593 | ) |
| 594 | first = true |
| 595 | for !endHeaders { |
| 596 | size := l.hBuf.Len() |
| 597 | if size > http2MaxFrameLen { |
| 598 | size = http2MaxFrameLen |
| 599 | } else { |
| 600 | endHeaders = true |
| 601 | } |
| 602 | if first { |
| 603 | first = false |
| 604 | err = l.framer.fr.WriteHeaders(http2.HeadersFrameParam{ |
| 605 | StreamID: streamID, |
| 606 | BlockFragment: l.hBuf.Next(size), |
| 607 | EndStream: endStream, |
| 608 | EndHeaders: endHeaders, |
| 609 | }) |
| 610 | } else { |
| 611 | err = l.framer.fr.WriteContinuation( |
| 612 | streamID, |
| 613 | endHeaders, |
| 614 | l.hBuf.Next(size), |
| 615 | ) |
| 616 | } |
| 617 | if err != nil { |
| 618 | return err |
| 619 | } |
| 620 | } |
| 621 | return nil |
| 622 | } |
| 623 | |
| 624 | func (l *loopyWriter) preprocessData(df *dataFrame) error { |
| 625 | str, ok := l.estdStreams[df.streamID] |
| 626 | if !ok { |
| 627 | return nil |
| 628 | } |
| 629 | // If we got data for a stream it means that |
| 630 | // stream was originated and the headers were sent out. |
| 631 | str.itl.enqueue(df) |
| 632 | if str.state == empty { |
| 633 | str.state = active |
| 634 | l.activeStreams.enqueue(str) |
| 635 | } |
| 636 | return nil |
| 637 | } |
| 638 | |
| 639 | func (l *loopyWriter) pingHandler(p *ping) error { |
| 640 | if !p.ack { |
| 641 | l.bdpEst.timesnap(p.data) |
| 642 | } |
| 643 | return l.framer.fr.WritePing(p.ack, p.data) |
| 644 | |
| 645 | } |
| 646 | |
| 647 | func (l *loopyWriter) outFlowControlSizeRequestHandler(o *outFlowControlSizeRequest) error { |
| 648 | o.resp <- l.sendQuota |
| 649 | return nil |
| 650 | } |
| 651 | |
| 652 | func (l *loopyWriter) cleanupStreamHandler(c *cleanupStream) error { |
| 653 | c.onWrite() |
| 654 | if str, ok := l.estdStreams[c.streamID]; ok { |
| 655 | // On the server side it could be a trailers-only response or |
| 656 | // a RST_STREAM before stream initialization thus the stream might |
| 657 | // not be established yet. |
| 658 | delete(l.estdStreams, c.streamID) |
| 659 | str.deleteSelf() |
| 660 | } |
| 661 | if c.rst { // If RST_STREAM needs to be sent. |
| 662 | if err := l.framer.fr.WriteRSTStream(c.streamID, c.rstCode); err != nil { |
| 663 | return err |
| 664 | } |
| 665 | } |
| 666 | if l.side == clientSide && l.draining && len(l.estdStreams) == 0 { |
| 667 | return ErrConnClosing |
| 668 | } |
| 669 | return nil |
| 670 | } |
| 671 | |
| 672 | func (l *loopyWriter) incomingGoAwayHandler(*incomingGoAway) error { |
| 673 | if l.side == clientSide { |
| 674 | l.draining = true |
| 675 | if len(l.estdStreams) == 0 { |
| 676 | return ErrConnClosing |
| 677 | } |
| 678 | } |
| 679 | return nil |
| 680 | } |
| 681 | |
| 682 | func (l *loopyWriter) goAwayHandler(g *goAway) error { |
| 683 | // Handling of outgoing GoAway is very specific to side. |
| 684 | if l.ssGoAwayHandler != nil { |
| 685 | draining, err := l.ssGoAwayHandler(g) |
| 686 | if err != nil { |
| 687 | return err |
| 688 | } |
| 689 | l.draining = draining |
| 690 | } |
| 691 | return nil |
| 692 | } |
| 693 | |
| 694 | func (l *loopyWriter) handle(i interface{}) error { |
| 695 | switch i := i.(type) { |
| 696 | case *incomingWindowUpdate: |
| 697 | return l.incomingWindowUpdateHandler(i) |
| 698 | case *outgoingWindowUpdate: |
| 699 | return l.outgoingWindowUpdateHandler(i) |
| 700 | case *incomingSettings: |
| 701 | return l.incomingSettingsHandler(i) |
| 702 | case *outgoingSettings: |
| 703 | return l.outgoingSettingsHandler(i) |
| 704 | case *headerFrame: |
| 705 | return l.headerHandler(i) |
| 706 | case *registerStream: |
| 707 | return l.registerStreamHandler(i) |
| 708 | case *cleanupStream: |
| 709 | return l.cleanupStreamHandler(i) |
| 710 | case *incomingGoAway: |
| 711 | return l.incomingGoAwayHandler(i) |
| 712 | case *dataFrame: |
| 713 | return l.preprocessData(i) |
| 714 | case *ping: |
| 715 | return l.pingHandler(i) |
| 716 | case *goAway: |
| 717 | return l.goAwayHandler(i) |
| 718 | case *outFlowControlSizeRequest: |
| 719 | return l.outFlowControlSizeRequestHandler(i) |
| 720 | default: |
| 721 | return fmt.Errorf("transport: unknown control message type %T", i) |
| 722 | } |
| 723 | } |
| 724 | |
| 725 | func (l *loopyWriter) applySettings(ss []http2.Setting) error { |
| 726 | for _, s := range ss { |
| 727 | switch s.ID { |
| 728 | case http2.SettingInitialWindowSize: |
| 729 | o := l.oiws |
| 730 | l.oiws = s.Val |
| 731 | if o < l.oiws { |
| 732 | // If the new limit is greater make all depleted streams active. |
| 733 | for _, stream := range l.estdStreams { |
| 734 | if stream.state == waitingOnStreamQuota { |
| 735 | stream.state = active |
| 736 | l.activeStreams.enqueue(stream) |
| 737 | } |
| 738 | } |
| 739 | } |
| 740 | case http2.SettingHeaderTableSize: |
| 741 | updateHeaderTblSize(l.hEnc, s.Val) |
| 742 | } |
| 743 | } |
| 744 | return nil |
| 745 | } |
| 746 | |
| 747 | // processData removes the first stream from active streams, writes out at most 16KB |
| 748 | // of its data and then puts it at the end of activeStreams if there's still more data |
| 749 | // to be sent and stream has some stream-level flow control. |
| 750 | func (l *loopyWriter) processData() (bool, error) { |
| 751 | if l.sendQuota == 0 { |
| 752 | return true, nil |
| 753 | } |
| 754 | str := l.activeStreams.dequeue() // Remove the first stream. |
| 755 | if str == nil { |
| 756 | return true, nil |
| 757 | } |
| 758 | dataItem := str.itl.peek().(*dataFrame) // Peek at the first data item this stream. |
| 759 | // A data item is represented by a dataFrame, since it later translates into |
| 760 | // multiple HTTP2 data frames. |
| 761 | // Every dataFrame has two buffers; h that keeps grpc-message header and d that is acutal data. |
| 762 | // As an optimization to keep wire traffic low, data from d is copied to h to make as big as the |
| 763 | // maximum possilbe HTTP2 frame size. |
| 764 | |
| 765 | if len(dataItem.h) == 0 && len(dataItem.d) == 0 { // Empty data frame |
| 766 | // Client sends out empty data frame with endStream = true |
| 767 | if err := l.framer.fr.WriteData(dataItem.streamID, dataItem.endStream, nil); err != nil { |
| 768 | return false, err |
| 769 | } |
| 770 | str.itl.dequeue() // remove the empty data item from stream |
| 771 | if str.itl.isEmpty() { |
| 772 | str.state = empty |
| 773 | } else if trailer, ok := str.itl.peek().(*headerFrame); ok { // the next item is trailers. |
| 774 | if err := l.writeHeader(trailer.streamID, trailer.endStream, trailer.hf, trailer.onWrite); err != nil { |
| 775 | return false, err |
| 776 | } |
| 777 | if err := l.cleanupStreamHandler(trailer.cleanup); err != nil { |
| 778 | return false, nil |
| 779 | } |
| 780 | } else { |
| 781 | l.activeStreams.enqueue(str) |
| 782 | } |
| 783 | return false, nil |
| 784 | } |
| 785 | var ( |
| 786 | idx int |
| 787 | buf []byte |
| 788 | ) |
| 789 | if len(dataItem.h) != 0 { // data header has not been written out yet. |
| 790 | buf = dataItem.h |
| 791 | } else { |
| 792 | idx = 1 |
| 793 | buf = dataItem.d |
| 794 | } |
| 795 | size := http2MaxFrameLen |
| 796 | if len(buf) < size { |
| 797 | size = len(buf) |
| 798 | } |
| 799 | if strQuota := int(l.oiws) - str.bytesOutStanding; strQuota <= 0 { // stream-level flow control. |
| 800 | str.state = waitingOnStreamQuota |
| 801 | return false, nil |
| 802 | } else if strQuota < size { |
| 803 | size = strQuota |
| 804 | } |
| 805 | |
| 806 | if l.sendQuota < uint32(size) { // connection-level flow control. |
| 807 | size = int(l.sendQuota) |
| 808 | } |
| 809 | // Now that outgoing flow controls are checked we can replenish str's write quota |
| 810 | str.wq.replenish(size) |
| 811 | var endStream bool |
| 812 | // If this is the last data message on this stream and all of it can be written in this iteration. |
| 813 | if dataItem.endStream && size == len(buf) { |
| 814 | // buf contains either data or it contains header but data is empty. |
| 815 | if idx == 1 || len(dataItem.d) == 0 { |
| 816 | endStream = true |
| 817 | } |
| 818 | } |
| 819 | if dataItem.onEachWrite != nil { |
| 820 | dataItem.onEachWrite() |
| 821 | } |
| 822 | if err := l.framer.fr.WriteData(dataItem.streamID, endStream, buf[:size]); err != nil { |
| 823 | return false, err |
| 824 | } |
| 825 | buf = buf[size:] |
| 826 | str.bytesOutStanding += size |
| 827 | l.sendQuota -= uint32(size) |
| 828 | if idx == 0 { |
| 829 | dataItem.h = buf |
| 830 | } else { |
| 831 | dataItem.d = buf |
| 832 | } |
| 833 | |
| 834 | if len(dataItem.h) == 0 && len(dataItem.d) == 0 { // All the data from that message was written out. |
| 835 | str.itl.dequeue() |
| 836 | } |
| 837 | if str.itl.isEmpty() { |
| 838 | str.state = empty |
| 839 | } else if trailer, ok := str.itl.peek().(*headerFrame); ok { // The next item is trailers. |
| 840 | if err := l.writeHeader(trailer.streamID, trailer.endStream, trailer.hf, trailer.onWrite); err != nil { |
| 841 | return false, err |
| 842 | } |
| 843 | if err := l.cleanupStreamHandler(trailer.cleanup); err != nil { |
| 844 | return false, err |
| 845 | } |
| 846 | } else if int(l.oiws)-str.bytesOutStanding <= 0 { // Ran out of stream quota. |
| 847 | str.state = waitingOnStreamQuota |
| 848 | } else { // Otherwise add it back to the list of active streams. |
| 849 | l.activeStreams.enqueue(str) |
| 850 | } |
| 851 | return false, nil |
| 852 | } |