cloudflared/quic/v3/manager.go
Devin Carr 952622a965 TUN-8709: Add session migration for datagram v3
When a registration response from cloudflared gets lost on it's way back to the edge, the edge service will retry and send another registration request. Since cloudflared already has bound the local UDP socket for the provided request id, we want to re-send the registration response.

There are three types of retries that the edge will send:

1. A retry from the same QUIC connection index; cloudflared will just respond back with a registration response and reset the idle timer for the session.
2. A retry from a different QUIC connection index; cloudflared will need to migrate the current session connection to this new QUIC connection and reset the idle timer for the session.
3. A retry to a different cloudflared connector; cloudflared will eventually time the session out since no further packets will arrive to the session at the original connector.

Closes TUN-8709
2024-11-06 12:06:07 -08:00

94 lines
3.2 KiB
Go

package v3
import (
"errors"
"net"
"net/netip"
"sync"
"github.com/rs/zerolog"
"github.com/cloudflare/cloudflared/ingress"
)
var (
// ErrSessionNotFound indicates that a session has not been registered yet for the request id.
ErrSessionNotFound = errors.New("session not found")
// ErrSessionBoundToOtherConn is returned when a registration already exists for a different connection.
ErrSessionBoundToOtherConn = errors.New("session is in use by another connection")
// ErrSessionAlreadyRegistered is returned when a registration already exists for this connection.
ErrSessionAlreadyRegistered = errors.New("session is already registered for this connection")
)
type SessionManager interface {
// RegisterSession will register a new session if it does not already exist for the request ID.
// During new session creation, the session will also bind the UDP socket for the origin.
// If the session exists for a different connection, it will return [ErrSessionBoundToOtherConn].
RegisterSession(request *UDPSessionRegistrationDatagram, conn DatagramConn) (Session, error)
// GetSession returns an active session if available for the provided connection.
// If the session does not exist, it will return [ErrSessionNotFound]. If the session exists for a different
// connection, it will return [ErrSessionBoundToOtherConn].
GetSession(requestID RequestID) (Session, error)
// UnregisterSession will remove a session from the current session manager. It will attempt to close the session
// before removal.
UnregisterSession(requestID RequestID)
}
type DialUDP func(dest netip.AddrPort) (*net.UDPConn, error)
type sessionManager struct {
sessions map[RequestID]Session
mutex sync.RWMutex
log *zerolog.Logger
}
func NewSessionManager(log *zerolog.Logger, originDialer DialUDP) SessionManager {
return &sessionManager{
sessions: make(map[RequestID]Session),
log: log,
}
}
func (s *sessionManager) RegisterSession(request *UDPSessionRegistrationDatagram, conn DatagramConn) (Session, error) {
s.mutex.Lock()
defer s.mutex.Unlock()
// Check to make sure session doesn't already exist for requestID
if session, exists := s.sessions[request.RequestID]; exists {
if conn.ID() == session.ConnectionID() {
return nil, ErrSessionAlreadyRegistered
}
return nil, ErrSessionBoundToOtherConn
}
// Attempt to bind the UDP socket for the new session
origin, err := ingress.DialUDPAddrPort(request.Dest)
if err != nil {
return nil, err
}
// Create and insert the new session in the map
session := NewSession(request.RequestID, request.IdleDurationHint, origin, conn, s.log)
s.sessions[request.RequestID] = session
return session, nil
}
func (s *sessionManager) GetSession(requestID RequestID) (Session, error) {
s.mutex.RLock()
defer s.mutex.RUnlock()
session, exists := s.sessions[requestID]
if exists {
return session, nil
}
return nil, ErrSessionNotFound
}
func (s *sessionManager) UnregisterSession(requestID RequestID) {
s.mutex.Lock()
defer s.mutex.Unlock()
// Get the session and make sure to close it if it isn't already closed
session, exists := s.sessions[requestID]
if exists {
// We ignore any errors when attempting to close the session
_ = session.Close()
}
delete(s.sessions, requestID)
}