cloudflared-mirror/origin/tunnel.go

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package origin
import (
"context"
"crypto/tls"
"fmt"
"net"
"runtime/debug"
"strings"
"sync"
"time"
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"github.com/google/uuid"
"github.com/pkg/errors"
"github.com/rs/zerolog"
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"golang.org/x/sync/errgroup"
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"github.com/cloudflare/cloudflared/connection"
"github.com/cloudflare/cloudflared/edgediscovery"
"github.com/cloudflare/cloudflared/h2mux"
"github.com/cloudflare/cloudflared/retry"
"github.com/cloudflare/cloudflared/signal"
"github.com/cloudflare/cloudflared/tunnelrpc"
tunnelpogs "github.com/cloudflare/cloudflared/tunnelrpc/pogs"
)
const (
dialTimeout = 15 * time.Second
lbProbeUserAgentPrefix = "Mozilla/5.0 (compatible; Cloudflare-Traffic-Manager/1.0; +https://www.cloudflare.com/traffic-manager/;"
FeatureSerializedHeaders = "serialized_headers"
FeatureQuickReconnects = "quick_reconnects"
)
type rpcName string
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const (
reconnect rpcName = "reconnect"
authenticate rpcName = " authenticate"
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)
type TunnelConfig struct {
ConnectionConfig *connection.Config
OSArch string
ClientID string
CloseConnOnce *sync.Once // Used to close connectedSignal no more than once
EdgeAddrs []string
HAConnections int
IncidentLookup IncidentLookup
IsAutoupdated bool
IsFreeTunnel bool
LBPool string
Tags []tunnelpogs.Tag
Log *zerolog.Logger
LogTransport *zerolog.Logger
Observer *connection.Observer
ReportedVersion string
Retries uint
RunFromTerminal bool
NamedTunnel *connection.NamedTunnelConfig
ClassicTunnel *connection.ClassicTunnelConfig
MuxerConfig *connection.MuxerConfig
ProtocolSelector connection.ProtocolSelector
EdgeTLSConfigs map[connection.Protocol]*tls.Config
}
func (c *TunnelConfig) RegistrationOptions(connectionID uint8, OriginLocalIP string, uuid uuid.UUID) *tunnelpogs.RegistrationOptions {
policy := tunnelrpc.ExistingTunnelPolicy_balance
if c.HAConnections <= 1 && c.LBPool == "" {
policy = tunnelrpc.ExistingTunnelPolicy_disconnect
}
return &tunnelpogs.RegistrationOptions{
ClientID: c.ClientID,
Version: c.ReportedVersion,
OS: c.OSArch,
ExistingTunnelPolicy: policy,
PoolName: c.LBPool,
Tags: c.Tags,
ConnectionID: connectionID,
OriginLocalIP: OriginLocalIP,
IsAutoupdated: c.IsAutoupdated,
RunFromTerminal: c.RunFromTerminal,
CompressionQuality: uint64(c.MuxerConfig.CompressionSetting),
UUID: uuid.String(),
Features: c.SupportedFeatures(),
}
}
func (c *TunnelConfig) ConnectionOptions(originLocalAddr string, numPreviousAttempts uint8) *tunnelpogs.ConnectionOptions {
// attempt to parse out origin IP, but don't fail since it's informational field
host, _, _ := net.SplitHostPort(originLocalAddr)
originIP := net.ParseIP(host)
return &tunnelpogs.ConnectionOptions{
Client: c.NamedTunnel.Client,
OriginLocalIP: originIP,
ReplaceExisting: c.ConnectionConfig.ReplaceExisting,
CompressionQuality: uint8(c.MuxerConfig.CompressionSetting),
NumPreviousAttempts: numPreviousAttempts,
}
}
func (c *TunnelConfig) SupportedFeatures() []string {
features := []string{FeatureSerializedHeaders}
if c.NamedTunnel == nil {
features = append(features, FeatureQuickReconnects)
}
return features
}
func StartTunnelDaemon(
ctx context.Context,
config *TunnelConfig,
connectedSignal *signal.Signal,
reconnectCh chan ReconnectSignal,
graceShutdownC <-chan struct{},
) error {
s, err := NewSupervisor(config, reconnectCh, graceShutdownC)
if err != nil {
return err
}
return s.Run(ctx, connectedSignal)
}
func ServeTunnelLoop(
ctx context.Context,
credentialManager *reconnectCredentialManager,
config *TunnelConfig,
addr *net.TCPAddr,
connIndex uint8,
connectedSignal *signal.Signal,
cloudflaredUUID uuid.UUID,
reconnectCh chan ReconnectSignal,
gracefulShutdownC <-chan struct{},
) error {
haConnections.Inc()
defer haConnections.Dec()
connLog := config.Log.With().Uint8(connection.LogFieldConnIndex, connIndex).Logger()
protocolFallback := &protocolFallback{
retry.BackoffHandler{MaxRetries: config.Retries},
config.ProtocolSelector.Current(),
false,
}
connectedFuse := h2mux.NewBooleanFuse()
go func() {
if connectedFuse.Await() {
connectedSignal.Notify()
}
}()
// Ensure the above goroutine will terminate if we return without connecting
defer connectedFuse.Fuse(false)
// Each connection to keep its own copy of protocol, because individual connections might fallback
// to another protocol when a particular metal doesn't support new protocol
for {
err, recoverable := ServeTunnel(
ctx,
&connLog,
credentialManager,
config,
addr,
connIndex,
connectedFuse,
protocolFallback,
cloudflaredUUID,
reconnectCh,
protocolFallback.protocol,
gracefulShutdownC,
)
if !recoverable {
return err
}
config.Observer.SendReconnect(connIndex)
duration, ok := protocolFallback.GetMaxBackoffDuration(ctx)
if !ok {
return err
}
connLog.Info().Msgf("Retrying connection in up to %s seconds", duration)
select {
case <-ctx.Done():
return ctx.Err()
case <-gracefulShutdownC:
return nil
case <-protocolFallback.BackoffTimer():
if !selectNextProtocol(&connLog, protocolFallback, config.ProtocolSelector) {
return err
}
}
}
}
// protocolFallback is a wrapper around backoffHandler that will try fallback option when backoff reaches
// max retries
type protocolFallback struct {
retry.BackoffHandler
protocol connection.Protocol
inFallback bool
}
func (pf *protocolFallback) reset() {
pf.ResetNow()
pf.inFallback = false
}
func (pf *protocolFallback) fallback(fallback connection.Protocol) {
pf.ResetNow()
pf.protocol = fallback
pf.inFallback = true
}
// selectNextProtocol picks connection protocol for the next retry iteration,
// returns true if it was able to pick the protocol, false if we are out of options and should stop retrying
func selectNextProtocol(
connLog *zerolog.Logger,
protocolBackoff *protocolFallback,
selector connection.ProtocolSelector,
) bool {
if protocolBackoff.ReachedMaxRetries() {
fallback, hasFallback := selector.Fallback()
if !hasFallback {
return false
}
// Already using fallback protocol, no point to retry
if protocolBackoff.protocol == fallback {
return false
}
connLog.Info().Msgf("Switching to fallback protocol %s", fallback)
protocolBackoff.fallback(fallback)
} else if !protocolBackoff.inFallback {
current := selector.Current()
if protocolBackoff.protocol != current {
protocolBackoff.protocol = current
connLog.Info().Msgf("Changing protocol to %s", current)
}
}
return true
}
// ServeTunnel runs a single tunnel connection, returns nil on graceful shutdown,
// on error returns a flag indicating if error can be retried
func ServeTunnel(
ctx context.Context,
connLog *zerolog.Logger,
credentialManager *reconnectCredentialManager,
config *TunnelConfig,
addr *net.TCPAddr,
connIndex uint8,
fuse *h2mux.BooleanFuse,
backoff *protocolFallback,
cloudflaredUUID uuid.UUID,
reconnectCh chan ReconnectSignal,
protocol connection.Protocol,
gracefulShutdownC <-chan struct{},
) (err error, recoverable bool) {
// Treat panics as recoverable errors
defer func() {
if r := recover(); r != nil {
var ok bool
err, ok = r.(error)
if !ok {
err = fmt.Errorf("ServeTunnel: %v", r)
}
err = errors.Wrapf(err, "stack trace: %s", string(debug.Stack()))
recoverable = true
}
}()
defer config.Observer.SendDisconnect(connIndex)
edgeConn, err := edgediscovery.DialEdge(ctx, dialTimeout, config.EdgeTLSConfigs[protocol], addr)
if err != nil {
connLog.Err(err).Msg("Unable to establish connection with Cloudflare edge")
return err, true
}
connectedFuse := &connectedFuse{
fuse: fuse,
backoff: backoff,
}
if protocol == connection.HTTP2 {
connOptions := config.ConnectionOptions(edgeConn.LocalAddr().String(), uint8(backoff.Retries()))
err = ServeHTTP2(
ctx,
connLog,
config,
edgeConn,
connOptions,
connIndex,
connectedFuse,
reconnectCh,
gracefulShutdownC,
)
} else {
err = ServeH2mux(
ctx,
connLog,
credentialManager,
config,
edgeConn,
connIndex,
connectedFuse,
cloudflaredUUID,
reconnectCh,
gracefulShutdownC,
)
}
if err != nil {
switch err := err.(type) {
case connection.DupConnRegisterTunnelError:
connLog.Err(err).Msg("Unable to establish connection.")
// don't retry this connection anymore, let supervisor pick a new address
return err, false
case connection.ServerRegisterTunnelError:
connLog.Err(err).Msg("Register tunnel error from server side")
// Don't send registration error return from server to Sentry. They are
// logged on server side
if incidents := config.IncidentLookup.ActiveIncidents(); len(incidents) > 0 {
connLog.Error().Msg(activeIncidentsMsg(incidents))
}
return err.Cause, !err.Permanent
case ReconnectSignal:
connLog.Info().
Uint8(connection.LogFieldConnIndex, connIndex).
Msgf("Restarting connection due to reconnect signal in %s", err.Delay)
err.DelayBeforeReconnect()
return err, true
default:
if err == context.Canceled {
connLog.Debug().Err(err).Msgf("Serve tunnel error")
return err, false
}
connLog.Err(err).Msgf("Serve tunnel error")
_, permanent := err.(unrecoverableError)
return err, !permanent
}
}
return nil, false
}
type unrecoverableError struct {
err error
}
func (r unrecoverableError) Error() string {
return r.err.Error()
}
func ServeH2mux(
ctx context.Context,
connLog *zerolog.Logger,
credentialManager *reconnectCredentialManager,
config *TunnelConfig,
edgeConn net.Conn,
connIndex uint8,
connectedFuse *connectedFuse,
cloudflaredUUID uuid.UUID,
reconnectCh chan ReconnectSignal,
gracefulShutdownC <-chan struct{},
) error {
connLog.Debug().Msgf("Connecting via h2mux")
// Returns error from parsing the origin URL or handshake errors
handler, err, recoverable := connection.NewH2muxConnection(
config.ConnectionConfig,
config.MuxerConfig,
edgeConn,
connIndex,
config.Observer,
gracefulShutdownC,
)
if err != nil {
if !recoverable {
return unrecoverableError{err}
}
return err
}
errGroup, serveCtx := errgroup.WithContext(ctx)
errGroup.Go(func() error {
if config.NamedTunnel != nil {
connOptions := config.ConnectionOptions(edgeConn.LocalAddr().String(), uint8(connectedFuse.backoff.Retries()))
return handler.ServeNamedTunnel(serveCtx, config.NamedTunnel, connOptions, connectedFuse)
}
registrationOptions := config.RegistrationOptions(connIndex, edgeConn.LocalAddr().String(), cloudflaredUUID)
return handler.ServeClassicTunnel(serveCtx, config.ClassicTunnel, credentialManager, registrationOptions, connectedFuse)
})
errGroup.Go(func() error {
return listenReconnect(serveCtx, reconnectCh, gracefulShutdownC)
})
return errGroup.Wait()
}
func ServeHTTP2(
ctx context.Context,
connLog *zerolog.Logger,
config *TunnelConfig,
tlsServerConn net.Conn,
connOptions *tunnelpogs.ConnectionOptions,
connIndex uint8,
connectedFuse connection.ConnectedFuse,
reconnectCh chan ReconnectSignal,
gracefulShutdownC <-chan struct{},
) error {
connLog.Debug().Msgf("Connecting via http2")
h2conn := connection.NewHTTP2Connection(
tlsServerConn,
config.ConnectionConfig,
config.NamedTunnel,
connOptions,
config.Observer,
connIndex,
connectedFuse,
gracefulShutdownC,
)
errGroup, serveCtx := errgroup.WithContext(ctx)
errGroup.Go(func() error {
return h2conn.Serve(serveCtx)
})
errGroup.Go(func() error {
err := listenReconnect(serveCtx, reconnectCh, gracefulShutdownC)
if err != nil {
// forcefully break the connection (this is only used for testing)
_ = tlsServerConn.Close()
}
return err
})
return errGroup.Wait()
}
func listenReconnect(ctx context.Context, reconnectCh <-chan ReconnectSignal, gracefulShutdownCh <-chan struct{}) error {
select {
case reconnect := <-reconnectCh:
return reconnect
case <-gracefulShutdownCh:
return nil
case <-ctx.Done():
return nil
}
}
type connectedFuse struct {
fuse *h2mux.BooleanFuse
backoff *protocolFallback
}
func (cf *connectedFuse) Connected() {
cf.fuse.Fuse(true)
cf.backoff.reset()
}
func (cf *connectedFuse) IsConnected() bool {
return cf.fuse.Value()
}
func activeIncidentsMsg(incidents []Incident) string {
preamble := "There is an active Cloudflare incident that may be related:"
if len(incidents) > 1 {
preamble = "There are active Cloudflare incidents that may be related:"
}
incidentStrings := []string{}
for _, incident := range incidents {
incidentString := fmt.Sprintf("%s (%s)", incident.Name, incident.URL())
incidentStrings = append(incidentStrings, incidentString)
}
return preamble + " " + strings.Join(incidentStrings, "; ")
}