forked from quic-go/quic-go
-
Notifications
You must be signed in to change notification settings - Fork 0
/
stream_framer.go
161 lines (129 loc) · 4.64 KB
/
stream_framer.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
package quic
import (
"github.com/lucas-clemente/quic-go/flowcontrol"
"github.com/lucas-clemente/quic-go/frames"
"github.com/lucas-clemente/quic-go/protocol"
"github.com/lucas-clemente/quic-go/utils"
)
type streamFramer struct {
streamsMap *streamsMap
flowControlManager flowcontrol.FlowControlManager
retransmissionQueue []*frames.StreamFrame
blockedFrameQueue []*frames.BlockedFrame
}
func newStreamFramer(streamsMap *streamsMap, flowControlManager flowcontrol.FlowControlManager) *streamFramer {
return &streamFramer{
streamsMap: streamsMap,
flowControlManager: flowControlManager,
}
}
func (f *streamFramer) AddFrameForRetransmission(frame *frames.StreamFrame) {
f.retransmissionQueue = append(f.retransmissionQueue, frame)
}
func (f *streamFramer) PopStreamFrames(maxLen protocol.ByteCount) []*frames.StreamFrame {
fs, currentLen := f.maybePopFramesForRetransmission(maxLen)
return append(fs, f.maybePopNormalFrames(maxLen-currentLen)...)
}
func (f *streamFramer) PopBlockedFrame() *frames.BlockedFrame {
if len(f.blockedFrameQueue) == 0 {
return nil
}
frame := f.blockedFrameQueue[0]
f.blockedFrameQueue = f.blockedFrameQueue[1:]
return frame
}
func (f *streamFramer) HasFramesForRetransmission() bool {
return len(f.retransmissionQueue) > 0
}
func (f *streamFramer) maybePopFramesForRetransmission(maxLen protocol.ByteCount) (res []*frames.StreamFrame, currentLen protocol.ByteCount) {
for len(f.retransmissionQueue) > 0 {
frame := f.retransmissionQueue[0]
frame.DataLenPresent = true
frameHeaderLen, _ := frame.MinLength(protocol.VersionWhatever) // can never error
if currentLen+frameHeaderLen >= maxLen {
break
}
currentLen += frameHeaderLen
splitFrame := maybeSplitOffFrame(frame, maxLen-currentLen)
if splitFrame != nil { // StreamFrame was split
res = append(res, splitFrame)
currentLen += splitFrame.DataLen()
break
}
f.retransmissionQueue = f.retransmissionQueue[1:]
res = append(res, frame)
currentLen += frame.DataLen()
}
return
}
func (f *streamFramer) maybePopNormalFrames(maxBytes protocol.ByteCount) (res []*frames.StreamFrame) {
frame := &frames.StreamFrame{DataLenPresent: true}
var currentLen protocol.ByteCount
fn := func(s *stream) (bool, error) {
if s == nil {
return true, nil
}
frame.StreamID = s.streamID
// not perfect, but thread-safe since writeOffset is only written when getting data
frame.Offset = s.writeOffset
frameHeaderBytes, _ := frame.MinLength(protocol.VersionWhatever) // can never error
if currentLen+frameHeaderBytes > maxBytes {
return false, nil // theoretically, we could find another stream that fits, but this is quite unlikely, so we stop here
}
maxLen := maxBytes - currentLen - frameHeaderBytes
var sendWindowSize protocol.ByteCount
if s.lenOfDataForWriting() != 0 {
sendWindowSize, _ = f.flowControlManager.SendWindowSize(s.streamID)
maxLen = utils.MinByteCount(maxLen, sendWindowSize)
}
if maxLen == 0 {
return true, nil
}
data := s.getDataForWriting(maxLen)
// This is unlikely, but check it nonetheless, the scheduler might have jumped in. Seems to happen in ~20% of cases in the tests.
shouldSendFin := s.shouldSendFin()
if data == nil && !shouldSendFin {
return true, nil
}
if shouldSendFin {
frame.FinBit = true
s.sentFin()
}
frame.Data = data
f.flowControlManager.AddBytesSent(s.streamID, protocol.ByteCount(len(data)))
// Finally, check if we are now FC blocked and should queue a BLOCKED frame
if f.flowControlManager.RemainingConnectionWindowSize() == 0 {
// We are now connection-level FC blocked
f.blockedFrameQueue = append(f.blockedFrameQueue, &frames.BlockedFrame{StreamID: 0})
} else if !frame.FinBit && sendWindowSize-frame.DataLen() == 0 {
// We are now stream-level FC blocked
f.blockedFrameQueue = append(f.blockedFrameQueue, &frames.BlockedFrame{StreamID: s.StreamID()})
}
res = append(res, frame)
currentLen += frameHeaderBytes + frame.DataLen()
if currentLen == maxBytes {
return false, nil
}
frame = &frames.StreamFrame{DataLenPresent: true}
return true, nil
}
f.streamsMap.RoundRobinIterate(fn)
return
}
// maybeSplitOffFrame removes the first n bytes and returns them as a separate frame. If n >= len(frame), nil is returned and nothing is modified.
func maybeSplitOffFrame(frame *frames.StreamFrame, n protocol.ByteCount) *frames.StreamFrame {
if n >= frame.DataLen() {
return nil
}
defer func() {
frame.Data = frame.Data[n:]
frame.Offset += n
}()
return &frames.StreamFrame{
FinBit: false,
StreamID: frame.StreamID,
Offset: frame.Offset,
Data: frame.Data[:n],
DataLenPresent: frame.DataLenPresent,
}
}