cloudflared-mirror/vendor/github.com/quic-go/quic-go/streams_map_incoming.go

196 lines
5.4 KiB
Go

package quic
import (
"context"
"sync"
"github.com/quic-go/quic-go/internal/protocol"
"github.com/quic-go/quic-go/internal/wire"
)
type incomingStream interface {
closeForShutdown(error)
}
// When a stream is deleted before it was accepted, we can't delete it from the map immediately.
// We need to wait until the application accepts it, and delete it then.
type incomingStreamEntry[T incomingStream] struct {
stream T
shouldDelete bool
}
type incomingStreamsMap[T incomingStream] struct {
mutex sync.RWMutex
newStreamChan chan struct{}
streamType protocol.StreamType
streams map[protocol.StreamNum]incomingStreamEntry[T]
nextStreamToAccept protocol.StreamNum // the next stream that will be returned by AcceptStream()
nextStreamToOpen protocol.StreamNum // the highest stream that the peer opened
maxStream protocol.StreamNum // the highest stream that the peer is allowed to open
maxNumStreams uint64 // maximum number of streams
newStream func(protocol.StreamNum) T
queueMaxStreamID func(*wire.MaxStreamsFrame)
closeErr error
}
func newIncomingStreamsMap[T incomingStream](
streamType protocol.StreamType,
newStream func(protocol.StreamNum) T,
maxStreams uint64,
queueControlFrame func(wire.Frame),
) *incomingStreamsMap[T] {
return &incomingStreamsMap[T]{
newStreamChan: make(chan struct{}, 1),
streamType: streamType,
streams: make(map[protocol.StreamNum]incomingStreamEntry[T]),
maxStream: protocol.StreamNum(maxStreams),
maxNumStreams: maxStreams,
newStream: newStream,
nextStreamToOpen: 1,
nextStreamToAccept: 1,
queueMaxStreamID: func(f *wire.MaxStreamsFrame) { queueControlFrame(f) },
}
}
func (m *incomingStreamsMap[T]) AcceptStream(ctx context.Context) (T, error) {
// drain the newStreamChan, so we don't check the map twice if the stream doesn't exist
select {
case <-m.newStreamChan:
default:
}
m.mutex.Lock()
var num protocol.StreamNum
var entry incomingStreamEntry[T]
for {
num = m.nextStreamToAccept
if m.closeErr != nil {
m.mutex.Unlock()
return *new(T), m.closeErr
}
var ok bool
entry, ok = m.streams[num]
if ok {
break
}
m.mutex.Unlock()
select {
case <-ctx.Done():
return *new(T), ctx.Err()
case <-m.newStreamChan:
}
m.mutex.Lock()
}
m.nextStreamToAccept++
// If this stream was completed before being accepted, we can delete it now.
if entry.shouldDelete {
if err := m.deleteStream(num); err != nil {
m.mutex.Unlock()
return *new(T), err
}
}
m.mutex.Unlock()
return entry.stream, nil
}
func (m *incomingStreamsMap[T]) GetOrOpenStream(num protocol.StreamNum) (T, error) {
m.mutex.RLock()
if num > m.maxStream {
m.mutex.RUnlock()
return *new(T), streamError{
message: "peer tried to open stream %d (current limit: %d)",
nums: []protocol.StreamNum{num, m.maxStream},
}
}
// if the num is smaller than the highest we accepted
// * this stream exists in the map, and we can return it, or
// * this stream was already closed, then we can return the nil
if num < m.nextStreamToOpen {
var s T
// If the stream was already queued for deletion, and is just waiting to be accepted, don't return it.
if entry, ok := m.streams[num]; ok && !entry.shouldDelete {
s = entry.stream
}
m.mutex.RUnlock()
return s, nil
}
m.mutex.RUnlock()
m.mutex.Lock()
// no need to check the two error conditions from above again
// * maxStream can only increase, so if the id was valid before, it definitely is valid now
// * highestStream is only modified by this function
for newNum := m.nextStreamToOpen; newNum <= num; newNum++ {
m.streams[newNum] = incomingStreamEntry[T]{stream: m.newStream(newNum)}
select {
case m.newStreamChan <- struct{}{}:
default:
}
}
m.nextStreamToOpen = num + 1
entry := m.streams[num]
m.mutex.Unlock()
return entry.stream, nil
}
func (m *incomingStreamsMap[T]) DeleteStream(num protocol.StreamNum) error {
m.mutex.Lock()
defer m.mutex.Unlock()
return m.deleteStream(num)
}
func (m *incomingStreamsMap[T]) deleteStream(num protocol.StreamNum) error {
if _, ok := m.streams[num]; !ok {
return streamError{
message: "tried to delete unknown incoming stream %d",
nums: []protocol.StreamNum{num},
}
}
// Don't delete this stream yet, if it was not yet accepted.
// Just save it to streamsToDelete map, to make sure it is deleted as soon as it gets accepted.
if num >= m.nextStreamToAccept {
entry, ok := m.streams[num]
if ok && entry.shouldDelete {
return streamError{
message: "tried to delete incoming stream %d multiple times",
nums: []protocol.StreamNum{num},
}
}
entry.shouldDelete = true
m.streams[num] = entry // can't assign to struct in map, so we need to reassign
return nil
}
delete(m.streams, num)
// queue a MAX_STREAM_ID frame, giving the peer the option to open a new stream
if m.maxNumStreams > uint64(len(m.streams)) {
maxStream := m.nextStreamToOpen + protocol.StreamNum(m.maxNumStreams-uint64(len(m.streams))) - 1
// Never send a value larger than protocol.MaxStreamCount.
if maxStream <= protocol.MaxStreamCount {
m.maxStream = maxStream
m.queueMaxStreamID(&wire.MaxStreamsFrame{
Type: m.streamType,
MaxStreamNum: m.maxStream,
})
}
}
return nil
}
func (m *incomingStreamsMap[T]) CloseWithError(err error) {
m.mutex.Lock()
m.closeErr = err
for _, entry := range m.streams {
entry.stream.closeForShutdown(err)
}
m.mutex.Unlock()
close(m.newStreamChan)
}