cloudflare/cloudflared
Publicmirrored from https://github.com/cloudflare/cloudflaredAvailable
datagramsession/manager.go
134lines · modecode
| 1 | package datagramsession |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "io" |
| 6 | |
| 7 | "github.com/google/uuid" |
| 8 | "github.com/rs/zerolog" |
| 9 | "golang.org/x/sync/errgroup" |
| 10 | ) |
| 11 | |
| 12 | const ( |
| 13 | requestChanCapacity = 16 |
| 14 | ) |
| 15 | |
| 16 | // Manager defines the APIs to manage sessions from the same transport. |
| 17 | type Manager interface { |
| 18 | // Serve starts the event loop |
| 19 | Serve(ctx context.Context) error |
| 20 | // RegisterSession starts tracking a session. Caller is responsible for starting the session |
| 21 | RegisterSession(ctx context.Context, sessionID uuid.UUID, dstConn io.ReadWriteCloser) (*Session, error) |
| 22 | // UnregisterSession stops tracking the session and terminates it |
| 23 | UnregisterSession(ctx context.Context, sessionID uuid.UUID) error |
| 24 | } |
| 25 | |
| 26 | type manager struct { |
| 27 | registrationChan chan *registerSessionEvent |
| 28 | unregistrationChan chan *unregisterSessionEvent |
| 29 | datagramChan chan *newDatagram |
| 30 | transport transport |
| 31 | sessions map[uuid.UUID]*Session |
| 32 | log *zerolog.Logger |
| 33 | } |
| 34 | |
| 35 | func NewManager(transport transport, log *zerolog.Logger) Manager { |
| 36 | return &manager{ |
| 37 | registrationChan: make(chan *registerSessionEvent), |
| 38 | unregistrationChan: make(chan *unregisterSessionEvent), |
| 39 | // datagramChan is buffered, so it can read more datagrams from transport while the event loop is processing other events |
| 40 | datagramChan: make(chan *newDatagram, requestChanCapacity), |
| 41 | transport: transport, |
| 42 | sessions: make(map[uuid.UUID]*Session), |
| 43 | log: log, |
| 44 | } |
| 45 | } |
| 46 | |
| 47 | func (m *manager) Serve(ctx context.Context) error { |
| 48 | errGroup, ctx := errgroup.WithContext(ctx) |
| 49 | errGroup.Go(func() error { |
| 50 | for { |
| 51 | sessionID, payload, err := m.transport.ReceiveFrom() |
| 52 | if err != nil { |
| 53 | m.log.Err(err).Msg("Failed to receive datagram from transport, closing session manager") |
| 54 | return err |
| 55 | } |
| 56 | datagram := &newDatagram{ |
| 57 | sessionID: sessionID, |
| 58 | payload: payload, |
| 59 | } |
| 60 | select { |
| 61 | case <-ctx.Done(): |
| 62 | return ctx.Err() |
| 63 | // Only the event loop routine can update/lookup the sessions map to avoid concurrent access |
| 64 | // Send the datagram to the event loop. It will find the session to send to |
| 65 | case m.datagramChan <- datagram: |
| 66 | } |
| 67 | } |
| 68 | }) |
| 69 | errGroup.Go(func() error { |
| 70 | for { |
| 71 | select { |
| 72 | case <-ctx.Done(): |
| 73 | return ctx.Err() |
| 74 | case datagram := <-m.datagramChan: |
| 75 | m.sendToSession(datagram) |
| 76 | case registration := <-m.registrationChan: |
| 77 | m.registerSession(ctx, registration) |
| 78 | // TODO: TUN-5422: Unregister inactive session upon timeout |
| 79 | case unregistration := <-m.unregistrationChan: |
| 80 | m.unregisterSession(unregistration) |
| 81 | } |
| 82 | } |
| 83 | }) |
| 84 | return errGroup.Wait() |
| 85 | } |
| 86 | |
| 87 | func (m *manager) RegisterSession(ctx context.Context, sessionID uuid.UUID, originProxy io.ReadWriteCloser) (*Session, error) { |
| 88 | event := newRegisterSessionEvent(sessionID, originProxy) |
| 89 | select { |
| 90 | case <-ctx.Done(): |
| 91 | return nil, ctx.Err() |
| 92 | case m.registrationChan <- event: |
| 93 | session := <-event.resultChan |
| 94 | return session, nil |
| 95 | } |
| 96 | } |
| 97 | |
| 98 | func (m *manager) registerSession(ctx context.Context, registration *registerSessionEvent) { |
| 99 | session := newSession(registration.sessionID, m.transport, registration.originProxy) |
| 100 | m.sessions[registration.sessionID] = session |
| 101 | registration.resultChan <- session |
| 102 | } |
| 103 | |
| 104 | func (m *manager) UnregisterSession(ctx context.Context, sessionID uuid.UUID) error { |
| 105 | event := &unregisterSessionEvent{sessionID: sessionID} |
| 106 | select { |
| 107 | case <-ctx.Done(): |
| 108 | return ctx.Err() |
| 109 | case m.unregistrationChan <- event: |
| 110 | return nil |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | func (m *manager) unregisterSession(unregistration *unregisterSessionEvent) { |
| 115 | session, ok := m.sessions[unregistration.sessionID] |
| 116 | if ok { |
| 117 | delete(m.sessions, unregistration.sessionID) |
| 118 | session.close() |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | func (m *manager) sendToSession(datagram *newDatagram) { |
| 123 | session, ok := m.sessions[datagram.sessionID] |
| 124 | if !ok { |
| 125 | m.log.Error().Str("sessionID", datagram.sessionID.String()).Msg("session not found") |
| 126 | return |
| 127 | } |
| 128 | // session writes to destination over a connected UDP socket, which should not be blocking, so this call doesn't |
| 129 | // need to run in another go routine |
| 130 | _, err := session.writeToDst(datagram.payload) |
| 131 | if err != nil { |
| 132 | m.log.Err(err).Str("sessionID", datagram.sessionID.String()).Msg("Failed to write payload to session") |
| 133 | } |
| 134 | } |
| 135 | |