341 lines
11 KiB
Go
341 lines
11 KiB
Go
package origin
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import (
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"context"
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"errors"
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"net"
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"time"
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"github.com/google/uuid"
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"github.com/cloudflare/cloudflared/connection"
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"github.com/cloudflare/cloudflared/edgediscovery"
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"github.com/cloudflare/cloudflared/h2mux"
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"github.com/cloudflare/cloudflared/logger"
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"github.com/cloudflare/cloudflared/signal"
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tunnelpogs "github.com/cloudflare/cloudflared/tunnelrpc/pogs"
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)
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const (
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// Waiting time before retrying a failed tunnel connection
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tunnelRetryDuration = time.Second * 10
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// SRV record resolution TTL
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resolveTTL = time.Hour
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// Interval between registering new tunnels
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registrationInterval = time.Second
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subsystemRefreshAuth = "refresh_auth"
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// Maximum exponent for 'Authenticate' exponential backoff
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refreshAuthMaxBackoff = 10
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// Waiting time before retrying a failed 'Authenticate' connection
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refreshAuthRetryDuration = time.Second * 10
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// Maximum time to make an Authenticate RPC
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authTokenTimeout = time.Second * 30
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)
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var (
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errEventDigestUnset = errors.New("event digest unset")
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)
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// Supervisor manages non-declarative tunnels. Establishes TCP connections with the edge, and
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// reconnects them if they disconnect.
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type Supervisor struct {
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cloudflaredUUID uuid.UUID
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config *TunnelConfig
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edgeIPs *edgediscovery.Edge
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lastResolve time.Time
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resolverC chan resolveResult
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tunnelErrors chan tunnelError
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tunnelsConnecting map[int]chan struct{}
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// nextConnectedIndex and nextConnectedSignal are used to wait for all
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// currently-connecting tunnels to finish connecting so we can reset backoff timer
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nextConnectedIndex int
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nextConnectedSignal chan struct{}
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logger logger.Service
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reconnectCredentialManager *reconnectCredentialManager
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useReconnectToken bool
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}
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type resolveResult struct {
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err error
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}
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type tunnelError struct {
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index int
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addr *net.TCPAddr
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err error
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}
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func NewSupervisor(config *TunnelConfig, cloudflaredUUID uuid.UUID) (*Supervisor, error) {
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var (
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edgeIPs *edgediscovery.Edge
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err error
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)
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if len(config.EdgeAddrs) > 0 {
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edgeIPs, err = edgediscovery.StaticEdge(config.Observer, config.EdgeAddrs)
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} else {
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edgeIPs, err = edgediscovery.ResolveEdge(config.Observer)
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}
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if err != nil {
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return nil, err
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}
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useReconnectToken := false
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if config.ClassicTunnel != nil {
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useReconnectToken = config.ClassicTunnel.UseReconnectToken
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}
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return &Supervisor{
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cloudflaredUUID: cloudflaredUUID,
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config: config,
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edgeIPs: edgeIPs,
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tunnelErrors: make(chan tunnelError),
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tunnelsConnecting: map[int]chan struct{}{},
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logger: config.Observer,
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reconnectCredentialManager: newReconnectCredentialManager(connection.MetricsNamespace, connection.TunnelSubsystem, config.HAConnections),
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useReconnectToken: useReconnectToken,
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}, nil
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}
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func (s *Supervisor) Run(ctx context.Context, connectedSignal *signal.Signal, reconnectCh chan ReconnectSignal) error {
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logger := s.config.Observer
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if err := s.initialize(ctx, connectedSignal, reconnectCh); err != nil {
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return err
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}
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var tunnelsWaiting []int
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tunnelsActive := s.config.HAConnections
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backoff := BackoffHandler{MaxRetries: s.config.Retries, BaseTime: tunnelRetryDuration, RetryForever: true}
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var backoffTimer <-chan time.Time
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refreshAuthBackoff := &BackoffHandler{MaxRetries: refreshAuthMaxBackoff, BaseTime: refreshAuthRetryDuration, RetryForever: true}
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var refreshAuthBackoffTimer <-chan time.Time
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if s.useReconnectToken {
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if timer, err := s.reconnectCredentialManager.RefreshAuth(ctx, refreshAuthBackoff, s.authenticate); err == nil {
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refreshAuthBackoffTimer = timer
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} else {
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logger.Errorf("supervisor: initial refreshAuth failed, retrying in %v: %s", refreshAuthRetryDuration, err)
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refreshAuthBackoffTimer = time.After(refreshAuthRetryDuration)
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}
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}
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for {
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select {
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// Context cancelled
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case <-ctx.Done():
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for tunnelsActive > 0 {
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<-s.tunnelErrors
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tunnelsActive--
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}
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return nil
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// startTunnel returned with error
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// (note that this may also be caused by context cancellation)
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case tunnelError := <-s.tunnelErrors:
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tunnelsActive--
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if tunnelError.err != nil {
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logger.Infof("supervisor: Tunnel disconnected due to error: %s", tunnelError.err)
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tunnelsWaiting = append(tunnelsWaiting, tunnelError.index)
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s.waitForNextTunnel(tunnelError.index)
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if backoffTimer == nil {
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backoffTimer = backoff.BackoffTimer()
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}
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// Previously we'd mark the edge address as bad here, but now we'll just silently use
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// another.
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}
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// Backoff was set and its timer expired
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case <-backoffTimer:
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backoffTimer = nil
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for _, index := range tunnelsWaiting {
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go s.startTunnel(ctx, index, s.newConnectedTunnelSignal(index), reconnectCh)
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}
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tunnelsActive += len(tunnelsWaiting)
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tunnelsWaiting = nil
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// Time to call Authenticate
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case <-refreshAuthBackoffTimer:
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newTimer, err := s.reconnectCredentialManager.RefreshAuth(ctx, refreshAuthBackoff, s.authenticate)
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if err != nil {
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logger.Errorf("supervisor: Authentication failed: %s", err)
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// Permanent failure. Leave the `select` without setting the
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// channel to be non-null, so we'll never hit this case of the `select` again.
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continue
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}
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refreshAuthBackoffTimer = newTimer
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// Tunnel successfully connected
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case <-s.nextConnectedSignal:
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if !s.waitForNextTunnel(s.nextConnectedIndex) && len(tunnelsWaiting) == 0 {
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// No more tunnels outstanding, clear backoff timer
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backoff.SetGracePeriod()
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}
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// DNS resolution returned
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case result := <-s.resolverC:
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s.lastResolve = time.Now()
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s.resolverC = nil
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if result.err == nil {
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logger.Debug("supervisor: Service discovery refresh complete")
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} else {
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logger.Errorf("supervisor: Service discovery error: %s", result.err)
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}
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}
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}
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}
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// Returns nil if initialization succeeded, else the initialization error.
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func (s *Supervisor) initialize(ctx context.Context, connectedSignal *signal.Signal, reconnectCh chan ReconnectSignal) error {
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logger := s.logger
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s.lastResolve = time.Now()
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availableAddrs := int(s.edgeIPs.AvailableAddrs())
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if s.config.HAConnections > availableAddrs {
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logger.Infof("You requested %d HA connections but I can give you at most %d.", s.config.HAConnections, availableAddrs)
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s.config.HAConnections = availableAddrs
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}
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go s.startFirstTunnel(ctx, connectedSignal, reconnectCh)
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select {
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case <-ctx.Done():
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<-s.tunnelErrors
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return ctx.Err()
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case tunnelError := <-s.tunnelErrors:
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return tunnelError.err
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case <-connectedSignal.Wait():
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}
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// At least one successful connection, so start the rest
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for i := 1; i < s.config.HAConnections; i++ {
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ch := signal.New(make(chan struct{}))
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go s.startTunnel(ctx, i, ch, reconnectCh)
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time.Sleep(registrationInterval)
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}
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return nil
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}
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// startTunnel starts the first tunnel connection. The resulting error will be sent on
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// s.tunnelErrors. It will send a signal via connectedSignal if registration succeed
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func (s *Supervisor) startFirstTunnel(ctx context.Context, connectedSignal *signal.Signal, reconnectCh chan ReconnectSignal) {
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var (
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addr *net.TCPAddr
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err error
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)
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const firstConnIndex = 0
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defer func() {
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s.tunnelErrors <- tunnelError{index: firstConnIndex, addr: addr, err: err}
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}()
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addr, err = s.edgeIPs.GetAddr(firstConnIndex)
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if err != nil {
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return
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}
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err = ServeTunnelLoop(ctx, s.reconnectCredentialManager, s.config, addr, firstConnIndex, connectedSignal, s.cloudflaredUUID, reconnectCh)
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// If the first tunnel disconnects, keep restarting it.
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edgeErrors := 0
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for s.unusedIPs() {
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if ctx.Err() != nil {
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return
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}
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switch err.(type) {
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case nil:
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return
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// try the next address if it was a dialError(network problem) or
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// dupConnRegisterTunnelError
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case edgediscovery.DialError, connection.DupConnRegisterTunnelError:
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edgeErrors++
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default:
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return
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}
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if edgeErrors >= 2 {
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addr, err = s.edgeIPs.GetDifferentAddr(firstConnIndex)
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if err != nil {
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return
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}
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}
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err = ServeTunnelLoop(ctx, s.reconnectCredentialManager, s.config, addr, firstConnIndex, connectedSignal, s.cloudflaredUUID, reconnectCh)
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}
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}
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// startTunnel starts a new tunnel connection. The resulting error will be sent on
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// s.tunnelErrors.
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func (s *Supervisor) startTunnel(ctx context.Context, index int, connectedSignal *signal.Signal, reconnectCh chan ReconnectSignal) {
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var (
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addr *net.TCPAddr
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err error
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)
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defer func() {
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s.tunnelErrors <- tunnelError{index: index, addr: addr, err: err}
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}()
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addr, err = s.edgeIPs.GetDifferentAddr(index)
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if err != nil {
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return
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}
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err = ServeTunnelLoop(ctx, s.reconnectCredentialManager, s.config, addr, uint8(index), connectedSignal, s.cloudflaredUUID, reconnectCh)
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}
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func (s *Supervisor) newConnectedTunnelSignal(index int) *signal.Signal {
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sig := make(chan struct{})
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s.tunnelsConnecting[index] = sig
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s.nextConnectedSignal = sig
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s.nextConnectedIndex = index
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return signal.New(sig)
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}
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func (s *Supervisor) waitForNextTunnel(index int) bool {
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delete(s.tunnelsConnecting, index)
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s.nextConnectedSignal = nil
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for k, v := range s.tunnelsConnecting {
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s.nextConnectedIndex = k
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s.nextConnectedSignal = v
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return true
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}
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return false
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}
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func (s *Supervisor) unusedIPs() bool {
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return s.edgeIPs.AvailableAddrs() > s.config.HAConnections
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}
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func (s *Supervisor) authenticate(ctx context.Context, numPreviousAttempts int) (tunnelpogs.AuthOutcome, error) {
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arbitraryEdgeIP, err := s.edgeIPs.GetAddrForRPC()
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if err != nil {
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return nil, err
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}
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edgeConn, err := edgediscovery.DialEdge(ctx, dialTimeout, s.config.TLSConfig, arbitraryEdgeIP)
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if err != nil {
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return nil, err
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}
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defer edgeConn.Close()
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handler := h2mux.MuxedStreamFunc(func(*h2mux.MuxedStream) error {
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// This callback is invoked by h2mux when the edge initiates a stream.
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return nil // noop
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})
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muxerConfig := s.config.MuxerConfig.H2MuxerConfig(handler, s.logger)
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muxer, err := h2mux.Handshake(edgeConn, edgeConn, *muxerConfig, h2mux.ActiveStreams)
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if err != nil {
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return nil, err
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}
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go muxer.Serve(ctx)
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defer func() {
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// If we don't wait for the muxer shutdown here, edgeConn.Close() runs before the muxer connections are done,
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// and the user sees log noise: "error writing data", "connection closed unexpectedly"
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<-muxer.Shutdown()
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}()
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stream, err := muxer.OpenRPCStream(ctx)
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if err != nil {
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return nil, err
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}
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rpcClient := connection.NewTunnelServerClient(ctx, stream, s.logger)
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defer rpcClient.Close()
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const arbitraryConnectionID = uint8(0)
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registrationOptions := s.config.RegistrationOptions(arbitraryConnectionID, edgeConn.LocalAddr().String(), s.cloudflaredUUID)
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registrationOptions.NumPreviousAttempts = uint8(numPreviousAttempts)
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return rpcClient.Authenticate(ctx, s.config.ClassicTunnel, registrationOptions)
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}
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