247 lines
6.5 KiB
Go
247 lines
6.5 KiB
Go
/*
|
|
*
|
|
* Copyright 2014 gRPC authors.
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*
|
|
*/
|
|
|
|
package transport
|
|
|
|
import (
|
|
"fmt"
|
|
"math"
|
|
"sync"
|
|
"time"
|
|
|
|
"golang.org/x/net/http2"
|
|
)
|
|
|
|
const (
|
|
// The default value of flow control window size in HTTP2 spec.
|
|
defaultWindowSize = 65535
|
|
// The initial window size for flow control.
|
|
initialWindowSize = defaultWindowSize // for an RPC
|
|
infinity = time.Duration(math.MaxInt64)
|
|
defaultClientKeepaliveTime = infinity
|
|
defaultClientKeepaliveTimeout = time.Duration(20 * time.Second)
|
|
defaultMaxStreamsClient = 100
|
|
defaultMaxConnectionIdle = infinity
|
|
defaultMaxConnectionAge = infinity
|
|
defaultMaxConnectionAgeGrace = infinity
|
|
defaultServerKeepaliveTime = time.Duration(2 * time.Hour)
|
|
defaultServerKeepaliveTimeout = time.Duration(20 * time.Second)
|
|
defaultKeepalivePolicyMinTime = time.Duration(5 * time.Minute)
|
|
// max window limit set by HTTP2 Specs.
|
|
maxWindowSize = math.MaxInt32
|
|
)
|
|
|
|
// The following defines various control items which could flow through
|
|
// the control buffer of transport. They represent different aspects of
|
|
// control tasks, e.g., flow control, settings, streaming resetting, etc.
|
|
type windowUpdate struct {
|
|
streamID uint32
|
|
increment uint32
|
|
flush bool
|
|
}
|
|
|
|
func (*windowUpdate) item() {}
|
|
|
|
type settings struct {
|
|
ack bool
|
|
ss []http2.Setting
|
|
}
|
|
|
|
func (*settings) item() {}
|
|
|
|
type resetStream struct {
|
|
streamID uint32
|
|
code http2.ErrCode
|
|
}
|
|
|
|
func (*resetStream) item() {}
|
|
|
|
type goAway struct {
|
|
code http2.ErrCode
|
|
debugData []byte
|
|
headsUp bool
|
|
closeConn bool
|
|
}
|
|
|
|
func (*goAway) item() {}
|
|
|
|
type flushIO struct {
|
|
}
|
|
|
|
func (*flushIO) item() {}
|
|
|
|
type ping struct {
|
|
ack bool
|
|
data [8]byte
|
|
}
|
|
|
|
func (*ping) item() {}
|
|
|
|
// quotaPool is a pool which accumulates the quota and sends it to acquire()
|
|
// when it is available.
|
|
type quotaPool struct {
|
|
c chan int
|
|
|
|
mu sync.Mutex
|
|
quota int
|
|
}
|
|
|
|
// newQuotaPool creates a quotaPool which has quota q available to consume.
|
|
func newQuotaPool(q int) *quotaPool {
|
|
qb := "aPool{
|
|
c: make(chan int, 1),
|
|
}
|
|
if q > 0 {
|
|
qb.c <- q
|
|
} else {
|
|
qb.quota = q
|
|
}
|
|
return qb
|
|
}
|
|
|
|
// add cancels the pending quota sent on acquired, incremented by v and sends
|
|
// it back on acquire.
|
|
func (qb *quotaPool) add(v int) {
|
|
qb.mu.Lock()
|
|
defer qb.mu.Unlock()
|
|
select {
|
|
case n := <-qb.c:
|
|
qb.quota += n
|
|
default:
|
|
}
|
|
qb.quota += v
|
|
if qb.quota <= 0 {
|
|
return
|
|
}
|
|
// After the pool has been created, this is the only place that sends on
|
|
// the channel. Since mu is held at this point and any quota that was sent
|
|
// on the channel has been retrieved, we know that this code will always
|
|
// place any positive quota value on the channel.
|
|
select {
|
|
case qb.c <- qb.quota:
|
|
qb.quota = 0
|
|
default:
|
|
}
|
|
}
|
|
|
|
// acquire returns the channel on which available quota amounts are sent.
|
|
func (qb *quotaPool) acquire() <-chan int {
|
|
return qb.c
|
|
}
|
|
|
|
// inFlow deals with inbound flow control
|
|
type inFlow struct {
|
|
mu sync.Mutex
|
|
// The inbound flow control limit for pending data.
|
|
limit uint32
|
|
// pendingData is the overall data which have been received but not been
|
|
// consumed by applications.
|
|
pendingData uint32
|
|
// The amount of data the application has consumed but grpc has not sent
|
|
// window update for them. Used to reduce window update frequency.
|
|
pendingUpdate uint32
|
|
// delta is the extra window update given by receiver when an application
|
|
// is reading data bigger in size than the inFlow limit.
|
|
delta uint32
|
|
}
|
|
|
|
// newLimit updates the inflow window to a new value n.
|
|
// It assumes that n is always greater than the old limit.
|
|
func (f *inFlow) newLimit(n uint32) uint32 {
|
|
f.mu.Lock()
|
|
defer f.mu.Unlock()
|
|
d := n - f.limit
|
|
f.limit = n
|
|
return d
|
|
}
|
|
|
|
func (f *inFlow) maybeAdjust(n uint32) uint32 {
|
|
if n > uint32(math.MaxInt32) {
|
|
n = uint32(math.MaxInt32)
|
|
}
|
|
f.mu.Lock()
|
|
defer f.mu.Unlock()
|
|
// estSenderQuota is the receiver's view of the maximum number of bytes the sender
|
|
// can send without a window update.
|
|
estSenderQuota := int32(f.limit - (f.pendingData + f.pendingUpdate))
|
|
// estUntransmittedData is the maximum number of bytes the sends might not have put
|
|
// on the wire yet. A value of 0 or less means that we have already received all or
|
|
// more bytes than the application is requesting to read.
|
|
estUntransmittedData := int32(n - f.pendingData) // Casting into int32 since it could be negative.
|
|
// This implies that unless we send a window update, the sender won't be able to send all the bytes
|
|
// for this message. Therefore we must send an update over the limit since there's an active read
|
|
// request from the application.
|
|
if estUntransmittedData > estSenderQuota {
|
|
// Sender's window shouldn't go more than 2^31 - 1 as speecified in the HTTP spec.
|
|
if f.limit+n > maxWindowSize {
|
|
f.delta = maxWindowSize - f.limit
|
|
} else {
|
|
// Send a window update for the whole message and not just the difference between
|
|
// estUntransmittedData and estSenderQuota. This will be helpful in case the message
|
|
// is padded; We will fallback on the current available window(at least a 1/4th of the limit).
|
|
f.delta = n
|
|
}
|
|
return f.delta
|
|
}
|
|
return 0
|
|
}
|
|
|
|
// onData is invoked when some data frame is received. It updates pendingData.
|
|
func (f *inFlow) onData(n uint32) error {
|
|
f.mu.Lock()
|
|
defer f.mu.Unlock()
|
|
f.pendingData += n
|
|
if f.pendingData+f.pendingUpdate > f.limit+f.delta {
|
|
return fmt.Errorf("received %d-bytes data exceeding the limit %d bytes", f.pendingData+f.pendingUpdate, f.limit)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// onRead is invoked when the application reads the data. It returns the window size
|
|
// to be sent to the peer.
|
|
func (f *inFlow) onRead(n uint32) uint32 {
|
|
f.mu.Lock()
|
|
defer f.mu.Unlock()
|
|
if f.pendingData == 0 {
|
|
return 0
|
|
}
|
|
f.pendingData -= n
|
|
if n > f.delta {
|
|
n -= f.delta
|
|
f.delta = 0
|
|
} else {
|
|
f.delta -= n
|
|
n = 0
|
|
}
|
|
f.pendingUpdate += n
|
|
if f.pendingUpdate >= f.limit/4 {
|
|
wu := f.pendingUpdate
|
|
f.pendingUpdate = 0
|
|
return wu
|
|
}
|
|
return 0
|
|
}
|
|
|
|
func (f *inFlow) resetPendingUpdate() uint32 {
|
|
f.mu.Lock()
|
|
defer f.mu.Unlock()
|
|
n := f.pendingUpdate
|
|
f.pendingUpdate = 0
|
|
return n
|
|
}
|