cloudflare/cloudflared
Publicmirrored from https://github.com/cloudflare/cloudflaredAvailable
h2mux/activestreammap.go
165lines · modecode
| 1 | package h2mux |
| 2 | |
| 3 | import ( |
| 4 | "sync" |
| 5 | |
| 6 | "golang.org/x/net/http2" |
| 7 | ) |
| 8 | |
| 9 | // activeStreamMap is used to moderate access to active streams between the read and write |
| 10 | // threads, and deny access to new peer streams while shutting down. |
| 11 | type activeStreamMap struct { |
| 12 | sync.RWMutex |
| 13 | // streams tracks open streams. |
| 14 | streams map[uint32]*MuxedStream |
| 15 | // streamsEmpty is a chan that should be closed when no more streams are open. |
| 16 | streamsEmpty chan struct{} |
| 17 | // nextStreamID is the next ID to use on our side of the connection. |
| 18 | // This is odd for clients, even for servers. |
| 19 | nextStreamID uint32 |
| 20 | // maxPeerStreamID is the ID of the most recent stream opened by the peer. |
| 21 | maxPeerStreamID uint32 |
| 22 | // ignoreNewStreams is true when the connection is being shut down. New streams |
| 23 | // cannot be registered. |
| 24 | ignoreNewStreams bool |
| 25 | } |
| 26 | |
| 27 | func newActiveStreamMap(useClientStreamNumbers bool) *activeStreamMap { |
| 28 | m := &activeStreamMap{ |
| 29 | streams: make(map[uint32]*MuxedStream), |
| 30 | streamsEmpty: make(chan struct{}), |
| 31 | nextStreamID: 1, |
| 32 | } |
| 33 | // Client initiated stream uses odd stream ID, server initiated stream uses even stream ID |
| 34 | if !useClientStreamNumbers { |
| 35 | m.nextStreamID = 2 |
| 36 | } |
| 37 | return m |
| 38 | } |
| 39 | |
| 40 | // Len returns the number of active streams. |
| 41 | func (m *activeStreamMap) Len() int { |
| 42 | m.RLock() |
| 43 | defer m.RUnlock() |
| 44 | return len(m.streams) |
| 45 | } |
| 46 | |
| 47 | func (m *activeStreamMap) Get(streamID uint32) (*MuxedStream, bool) { |
| 48 | m.RLock() |
| 49 | defer m.RUnlock() |
| 50 | stream, ok := m.streams[streamID] |
| 51 | return stream, ok |
| 52 | } |
| 53 | |
| 54 | // Set returns true if the stream was assigned successfully. If a stream |
| 55 | // already existed with that ID or we are shutting down, return false. |
| 56 | func (m *activeStreamMap) Set(newStream *MuxedStream) bool { |
| 57 | m.Lock() |
| 58 | defer m.Unlock() |
| 59 | if _, ok := m.streams[newStream.streamID]; ok { |
| 60 | return false |
| 61 | } |
| 62 | if m.ignoreNewStreams { |
| 63 | return false |
| 64 | } |
| 65 | m.streams[newStream.streamID] = newStream |
| 66 | return true |
| 67 | } |
| 68 | |
| 69 | // Delete stops tracking the stream. It should be called only after it is closed and resetted. |
| 70 | func (m *activeStreamMap) Delete(streamID uint32) { |
| 71 | m.Lock() |
| 72 | defer m.Unlock() |
| 73 | delete(m.streams, streamID) |
| 74 | if len(m.streams) == 0 && m.streamsEmpty != nil { |
| 75 | close(m.streamsEmpty) |
| 76 | m.streamsEmpty = nil |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | // Shutdown blocks new streams from being created. It returns a channel that receives an event |
| 81 | // once the last stream has closed, or nil if a shutdown is in progress. |
| 82 | func (m *activeStreamMap) Shutdown() <-chan struct{} { |
| 83 | m.Lock() |
| 84 | defer m.Unlock() |
| 85 | if m.ignoreNewStreams { |
| 86 | // already shutting down |
| 87 | return nil |
| 88 | } |
| 89 | m.ignoreNewStreams = true |
| 90 | done := make(chan struct{}) |
| 91 | if len(m.streams) == 0 { |
| 92 | // nothing to shut down |
| 93 | close(done) |
| 94 | return done |
| 95 | } |
| 96 | m.streamsEmpty = done |
| 97 | return done |
| 98 | } |
| 99 | |
| 100 | // AcquireLocalID acquires a new stream ID for a stream you're opening. |
| 101 | func (m *activeStreamMap) AcquireLocalID() uint32 { |
| 102 | m.Lock() |
| 103 | defer m.Unlock() |
| 104 | x := m.nextStreamID |
| 105 | m.nextStreamID += 2 |
| 106 | return x |
| 107 | } |
| 108 | |
| 109 | // ObservePeerID observes the ID of a stream opened by the peer. It returns true if we should accept |
| 110 | // the new stream, or false to reject it. The ErrCode gives the reason why. |
| 111 | func (m *activeStreamMap) AcquirePeerID(streamID uint32) (bool, http2.ErrCode) { |
| 112 | m.Lock() |
| 113 | defer m.Unlock() |
| 114 | switch { |
| 115 | case m.ignoreNewStreams: |
| 116 | return false, http2.ErrCodeStreamClosed |
| 117 | case streamID > m.maxPeerStreamID: |
| 118 | m.maxPeerStreamID = streamID |
| 119 | return true, http2.ErrCodeNo |
| 120 | default: |
| 121 | return false, http2.ErrCodeStreamClosed |
| 122 | } |
| 123 | } |
| 124 | |
| 125 | // IsPeerStreamID is true if the stream ID belongs to the peer. |
| 126 | func (m *activeStreamMap) IsPeerStreamID(streamID uint32) bool { |
| 127 | m.RLock() |
| 128 | defer m.RUnlock() |
| 129 | return (streamID % 2) != (m.nextStreamID % 2) |
| 130 | } |
| 131 | |
| 132 | // IsLocalStreamID is true if it is a stream we have opened, even if it is now closed. |
| 133 | func (m *activeStreamMap) IsLocalStreamID(streamID uint32) bool { |
| 134 | m.RLock() |
| 135 | defer m.RUnlock() |
| 136 | return (streamID%2) == (m.nextStreamID%2) && streamID < m.nextStreamID |
| 137 | } |
| 138 | |
| 139 | // LastPeerStreamID returns the most recently opened peer stream ID. |
| 140 | func (m *activeStreamMap) LastPeerStreamID() uint32 { |
| 141 | m.RLock() |
| 142 | defer m.RUnlock() |
| 143 | return m.maxPeerStreamID |
| 144 | } |
| 145 | |
| 146 | // LastLocalStreamID returns the most recently opened local stream ID. |
| 147 | func (m *activeStreamMap) LastLocalStreamID() uint32 { |
| 148 | m.RLock() |
| 149 | defer m.RUnlock() |
| 150 | if m.nextStreamID > 1 { |
| 151 | return m.nextStreamID - 2 |
| 152 | } |
| 153 | return 0 |
| 154 | } |
| 155 | |
| 156 | // Abort closes every active stream and prevents new ones being created. This should be used to |
| 157 | // return errors in pending read/writes when the underlying connection goes away. |
| 158 | func (m *activeStreamMap) Abort() { |
| 159 | m.Lock() |
| 160 | defer m.Unlock() |
| 161 | for _, stream := range m.streams { |
| 162 | stream.Close() |
| 163 | } |
| 164 | m.ignoreNewStreams = true |
| 165 | } |
| 166 | |