302 lines
11 KiB
Go
302 lines
11 KiB
Go
package v3
|
|
|
|
import (
|
|
"context"
|
|
"errors"
|
|
"time"
|
|
|
|
"github.com/rs/zerolog"
|
|
)
|
|
|
|
const (
|
|
// Allocating a 16 channel buffer here allows for the writer to be slightly faster than the reader.
|
|
// This has worked previously well for datagramv2, so we will start with this as well
|
|
demuxChanCapacity = 16
|
|
|
|
logSrcKey = "src"
|
|
logDstKey = "dst"
|
|
logDurationKey = "durationMS"
|
|
)
|
|
|
|
// DatagramConn is the bridge that multiplexes writes and reads of datagrams for UDP sessions and ICMP packets to
|
|
// a connection.
|
|
type DatagramConn interface {
|
|
DatagramWriter
|
|
// Serve provides a server interface to process and handle incoming QUIC datagrams and demux their datagram v3 payloads.
|
|
Serve(context.Context) error
|
|
// ID indicates connection index identifier
|
|
ID() uint8
|
|
}
|
|
|
|
// DatagramWriter provides the Muxer interface to create proper Datagrams when sending over a connection.
|
|
type DatagramWriter interface {
|
|
SendUDPSessionDatagram(datagram []byte) error
|
|
SendUDPSessionResponse(id RequestID, resp SessionRegistrationResp) error
|
|
//SendICMPPacket(packet packet.IP) error
|
|
}
|
|
|
|
// QuicConnection provides an interface that matches [quic.Connection] for only the datagram operations.
|
|
//
|
|
// We currently rely on the mutex for the [quic.Connection.SendDatagram] and [quic.Connection.ReceiveDatagram] and
|
|
// do not have any locking for them. If the implementation in quic-go were to ever change, we would need to make
|
|
// sure that we lock properly on these operations.
|
|
type QuicConnection interface {
|
|
Context() context.Context
|
|
SendDatagram(payload []byte) error
|
|
ReceiveDatagram(context.Context) ([]byte, error)
|
|
}
|
|
|
|
type datagramConn struct {
|
|
conn QuicConnection
|
|
index uint8
|
|
sessionManager SessionManager
|
|
metrics Metrics
|
|
logger *zerolog.Logger
|
|
|
|
datagrams chan []byte
|
|
readErrors chan error
|
|
}
|
|
|
|
func NewDatagramConn(conn QuicConnection, sessionManager SessionManager, index uint8, metrics Metrics, logger *zerolog.Logger) DatagramConn {
|
|
log := logger.With().Uint8("datagramVersion", 3).Logger()
|
|
return &datagramConn{
|
|
conn: conn,
|
|
index: index,
|
|
sessionManager: sessionManager,
|
|
metrics: metrics,
|
|
logger: &log,
|
|
datagrams: make(chan []byte, demuxChanCapacity),
|
|
readErrors: make(chan error, 2),
|
|
}
|
|
}
|
|
|
|
func (c datagramConn) ID() uint8 {
|
|
return c.index
|
|
}
|
|
|
|
func (c *datagramConn) SendUDPSessionDatagram(datagram []byte) error {
|
|
return c.conn.SendDatagram(datagram)
|
|
}
|
|
|
|
func (c *datagramConn) SendUDPSessionResponse(id RequestID, resp SessionRegistrationResp) error {
|
|
datagram := UDPSessionRegistrationResponseDatagram{
|
|
RequestID: id,
|
|
ResponseType: resp,
|
|
}
|
|
data, err := datagram.MarshalBinary()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
return c.conn.SendDatagram(data)
|
|
}
|
|
|
|
var errReadTimeout error = errors.New("receive datagram timeout")
|
|
|
|
// pollDatagrams will read datagrams from the underlying connection until the provided context is done.
|
|
func (c *datagramConn) pollDatagrams(ctx context.Context) {
|
|
for ctx.Err() == nil {
|
|
datagram, err := c.conn.ReceiveDatagram(ctx)
|
|
// If the read returns an error, we want to return the failure to the channel.
|
|
if err != nil {
|
|
c.readErrors <- err
|
|
return
|
|
}
|
|
c.datagrams <- datagram
|
|
}
|
|
if ctx.Err() != nil {
|
|
c.readErrors <- ctx.Err()
|
|
}
|
|
}
|
|
|
|
// Serve will begin the process of receiving datagrams from the [quic.Connection] and demuxing them to their destination.
|
|
// The [DatagramConn] when serving, will be responsible for the sessions it accepts.
|
|
func (c *datagramConn) Serve(ctx context.Context) error {
|
|
connCtx := c.conn.Context()
|
|
// We want to make sure that we cancel the reader context if the Serve method returns. This could also mean that the
|
|
// underlying connection is also closing, but that is handled outside of the context of the datagram muxer.
|
|
readCtx, cancel := context.WithCancel(connCtx)
|
|
defer cancel()
|
|
go c.pollDatagrams(readCtx)
|
|
for {
|
|
// We make sure to monitor the context of cloudflared and the underlying connection to return if any errors occur.
|
|
var datagram []byte
|
|
select {
|
|
// Monitor the context of cloudflared
|
|
case <-ctx.Done():
|
|
return ctx.Err()
|
|
// Monitor the context of the underlying connection
|
|
case <-connCtx.Done():
|
|
return connCtx.Err()
|
|
// Monitor for any hard errors from reading the connection
|
|
case err := <-c.readErrors:
|
|
return err
|
|
// Otherwise, wait and dequeue datagrams as they come in
|
|
case d := <-c.datagrams:
|
|
datagram = d
|
|
}
|
|
|
|
// Each incoming datagram will be processed in a new go routine to handle the demuxing and action associated.
|
|
go func() {
|
|
typ, err := ParseDatagramType(datagram)
|
|
if err != nil {
|
|
c.logger.Err(err).Msgf("unable to parse datagram type: %d", typ)
|
|
return
|
|
}
|
|
switch typ {
|
|
case UDPSessionRegistrationType:
|
|
reg := &UDPSessionRegistrationDatagram{}
|
|
err := reg.UnmarshalBinary(datagram)
|
|
if err != nil {
|
|
c.logger.Err(err).Msgf("unable to unmarshal session registration datagram")
|
|
return
|
|
}
|
|
logger := c.logger.With().Str(logFlowID, reg.RequestID.String()).Logger()
|
|
// We bind the new session to the quic connection context instead of cloudflared context to allow for the
|
|
// quic connection to close and close only the sessions bound to it. Closing of cloudflared will also
|
|
// initiate the close of the quic connection, so we don't have to worry about the application context
|
|
// in the scope of a session.
|
|
c.handleSessionRegistrationDatagram(connCtx, reg, &logger)
|
|
case UDPSessionPayloadType:
|
|
payload := &UDPSessionPayloadDatagram{}
|
|
err := payload.UnmarshalBinary(datagram)
|
|
if err != nil {
|
|
c.logger.Err(err).Msgf("unable to unmarshal session payload datagram")
|
|
return
|
|
}
|
|
logger := c.logger.With().Str(logFlowID, payload.RequestID.String()).Logger()
|
|
c.handleSessionPayloadDatagram(payload, &logger)
|
|
case UDPSessionRegistrationResponseType:
|
|
// cloudflared should never expect to receive UDP session responses as it will not initiate new
|
|
// sessions towards the edge.
|
|
c.logger.Error().Msgf("unexpected datagram type received: %d", UDPSessionRegistrationResponseType)
|
|
return
|
|
default:
|
|
c.logger.Error().Msgf("unknown datagram type received: %d", typ)
|
|
}
|
|
}()
|
|
}
|
|
}
|
|
|
|
// This method handles new registrations of a session and the serve loop for the session.
|
|
func (c *datagramConn) handleSessionRegistrationDatagram(ctx context.Context, datagram *UDPSessionRegistrationDatagram, logger *zerolog.Logger) {
|
|
log := logger.With().
|
|
Str(logFlowID, datagram.RequestID.String()).
|
|
Str(logDstKey, datagram.Dest.String()).
|
|
Logger()
|
|
session, err := c.sessionManager.RegisterSession(datagram, c)
|
|
switch err {
|
|
case nil:
|
|
// Continue as normal
|
|
case ErrSessionAlreadyRegistered:
|
|
// Session is already registered and likely the response got lost
|
|
c.handleSessionAlreadyRegistered(datagram.RequestID, &log)
|
|
return
|
|
case ErrSessionBoundToOtherConn:
|
|
// Session is already registered but to a different connection
|
|
c.handleSessionMigration(datagram.RequestID, &log)
|
|
return
|
|
default:
|
|
log.Err(err).Msgf("flow registration failure")
|
|
c.handleSessionRegistrationFailure(datagram.RequestID, &log)
|
|
return
|
|
}
|
|
log = log.With().Str(logSrcKey, session.LocalAddr().String()).Logger()
|
|
c.metrics.IncrementFlows()
|
|
// Make sure to eventually remove the session from the session manager when the session is closed
|
|
defer c.sessionManager.UnregisterSession(session.ID())
|
|
defer c.metrics.DecrementFlows()
|
|
|
|
// Respond that we are able to process the new session
|
|
err = c.SendUDPSessionResponse(datagram.RequestID, ResponseOk)
|
|
if err != nil {
|
|
log.Err(err).Msgf("flow registration failure: unable to send session registration response")
|
|
return
|
|
}
|
|
|
|
// We bind the context of the session to the [quic.Connection] that initiated the session.
|
|
// [Session.Serve] is blocking and will continue this go routine till the end of the session lifetime.
|
|
start := time.Now()
|
|
err = session.Serve(ctx)
|
|
elapsedMS := time.Now().Sub(start).Milliseconds()
|
|
log = log.With().Int64(logDurationKey, elapsedMS).Logger()
|
|
if err == nil {
|
|
// We typically don't expect a session to close without some error response. [SessionIdleErr] is the typical
|
|
// expected error response.
|
|
log.Warn().Msg("flow closed: no explicit close or timeout elapsed")
|
|
return
|
|
}
|
|
// SessionIdleErr and SessionCloseErr are valid and successful error responses to end a session.
|
|
if errors.Is(err, SessionIdleErr{}) || errors.Is(err, SessionCloseErr) {
|
|
log.Debug().Msgf("flow closed: %s", err.Error())
|
|
return
|
|
}
|
|
|
|
// All other errors should be reported as errors
|
|
log.Err(err).Msgf("flow closed with an error")
|
|
}
|
|
|
|
func (c *datagramConn) handleSessionAlreadyRegistered(requestID RequestID, logger *zerolog.Logger) {
|
|
// Send another registration response since the session is already active
|
|
err := c.SendUDPSessionResponse(requestID, ResponseOk)
|
|
if err != nil {
|
|
logger.Err(err).Msgf("flow registration failure: unable to send an additional flow registration response")
|
|
return
|
|
}
|
|
|
|
session, err := c.sessionManager.GetSession(requestID)
|
|
if err != nil {
|
|
// If for some reason we can not find the session after attempting to register it, we can just return
|
|
// instead of trying to reset the idle timer for it.
|
|
return
|
|
}
|
|
// The session is already running in another routine so we want to restart the idle timeout since no proxied
|
|
// packets have come down yet.
|
|
session.ResetIdleTimer()
|
|
c.metrics.RetryFlowResponse()
|
|
logger.Debug().Msgf("flow registration response retry")
|
|
}
|
|
|
|
func (c *datagramConn) handleSessionMigration(requestID RequestID, logger *zerolog.Logger) {
|
|
// We need to migrate the currently running session to this edge connection.
|
|
session, err := c.sessionManager.GetSession(requestID)
|
|
if err != nil {
|
|
// If for some reason we can not find the session after attempting to register it, we can just return
|
|
// instead of trying to reset the idle timer for it.
|
|
return
|
|
}
|
|
|
|
// Migrate the session to use this edge connection instead of the currently running one.
|
|
// We also pass in this connection's logger to override the existing logger for the session.
|
|
session.Migrate(c, c.logger)
|
|
|
|
// Send another registration response since the session is already active
|
|
err = c.SendUDPSessionResponse(requestID, ResponseOk)
|
|
if err != nil {
|
|
logger.Err(err).Msgf("flow registration failure: unable to send an additional flow registration response")
|
|
return
|
|
}
|
|
logger.Debug().Msgf("flow registration migration")
|
|
}
|
|
|
|
func (c *datagramConn) handleSessionRegistrationFailure(requestID RequestID, logger *zerolog.Logger) {
|
|
err := c.SendUDPSessionResponse(requestID, ResponseUnableToBindSocket)
|
|
if err != nil {
|
|
logger.Err(err).Msgf("unable to send flow registration error response (%d)", ResponseUnableToBindSocket)
|
|
}
|
|
}
|
|
|
|
// Handles incoming datagrams that need to be sent to a registered session.
|
|
func (c *datagramConn) handleSessionPayloadDatagram(datagram *UDPSessionPayloadDatagram, logger *zerolog.Logger) {
|
|
s, err := c.sessionManager.GetSession(datagram.RequestID)
|
|
if err != nil {
|
|
logger.Err(err).Msgf("unable to find flow")
|
|
return
|
|
}
|
|
// We ignore the bytes written to the socket because any partial write must return an error.
|
|
_, err = s.Write(datagram.Payload)
|
|
if err != nil {
|
|
logger.Err(err).Msgf("unable to write payload for the flow")
|
|
return
|
|
}
|
|
}
|