mirror of
https://github.com/slackhq/nebula.git
synced 2026-05-16 12:57:38 +02:00
410 lines
12 KiB
Go
410 lines
12 KiB
Go
package nebula
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import (
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"context"
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"encoding/binary"
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"errors"
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"fmt"
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"log/slog"
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"net/netip"
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"sync/atomic"
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"github.com/slackhq/nebula/cert"
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"github.com/slackhq/nebula/config"
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"github.com/slackhq/nebula/header"
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)
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type relayManager struct {
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l *slog.Logger
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hostmap *HostMap
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amRelay atomic.Bool
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}
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func NewRelayManager(ctx context.Context, l *slog.Logger, hostmap *HostMap, c *config.C) *relayManager {
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rm := &relayManager{
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l: l,
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hostmap: hostmap,
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}
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rm.reload(c, true)
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c.RegisterReloadCallback(func(c *config.C) {
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err := rm.reload(c, false)
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if err != nil {
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rm.l.Error("Failed to reload relay_manager", "error", err)
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}
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})
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return rm
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}
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func (rm *relayManager) reload(c *config.C, initial bool) error {
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if initial || c.HasChanged("relay.am_relay") {
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rm.setAmRelay(c.GetBool("relay.am_relay", false))
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}
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return nil
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}
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func (rm *relayManager) GetAmRelay() bool {
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return rm.amRelay.Load()
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}
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func (rm *relayManager) setAmRelay(v bool) {
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rm.amRelay.Store(v)
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}
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// AddRelay finds an available relay index on the hostmap, and associates the relay info with it.
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// relayHostInfo is the Nebula peer which can be used as a relay to access the target vpnIp.
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func AddRelay(l *slog.Logger, relayHostInfo *HostInfo, hm *HostMap, vpnIp netip.Addr, remoteIdx *uint32, relayType int, state int) (uint32, error) {
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hm.Lock()
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defer hm.Unlock()
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for range 32 {
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index, err := generateIndex(l)
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if err != nil {
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return 0, err
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}
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_, inRelays := hm.Relays[index]
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if !inRelays {
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// Avoid standing up a relay that can't be used since only the primary hostinfo
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// will be pointed to by the relay logic
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//TODO: if there was an existing primary and it had relay state, should we merge?
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hm.unlockedMakePrimary(relayHostInfo)
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hm.Relays[index] = relayHostInfo
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newRelay := Relay{
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Type: relayType,
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State: state,
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LocalIndex: index,
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PeerAddr: vpnIp,
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}
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if remoteIdx != nil {
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newRelay.RemoteIndex = *remoteIdx
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}
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relayHostInfo.relayState.InsertRelay(vpnIp, index, &newRelay)
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return index, nil
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}
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}
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return 0, errors.New("failed to generate unique localIndexId")
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}
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// EstablishRelay updates a Requested Relay to become an Established Relay, which can pass traffic.
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func (rm *relayManager) EstablishRelay(relayHostInfo *HostInfo, m *NebulaControl) (*Relay, error) {
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relay, ok := relayHostInfo.relayState.CompleteRelayByIdx(m.InitiatorRelayIndex, m.ResponderRelayIndex)
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if !ok {
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var relayFrom, relayTo any
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if m.RelayFromAddr == nil {
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relayFrom = m.OldRelayFromAddr
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} else {
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relayFrom = m.RelayFromAddr
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}
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if m.RelayToAddr == nil {
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relayTo = m.OldRelayToAddr
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} else {
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relayTo = m.RelayToAddr
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}
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rm.l.Info("relayManager failed to update relay",
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"relay", relayHostInfo.vpnAddrs[0],
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"initiatorRelayIndex", m.InitiatorRelayIndex,
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"relayFrom", relayFrom,
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"relayTo", relayTo,
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)
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return nil, fmt.Errorf("unknown relay")
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}
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return relay, nil
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}
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func (rm *relayManager) HandleControlMsg(h *HostInfo, d []byte, f *Interface) {
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msg := &NebulaControl{}
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err := msg.Unmarshal(d)
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if err != nil {
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h.logger(f.l).Error("Failed to unmarshal control message", "error", err)
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return
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}
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var v cert.Version
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if msg.OldRelayFromAddr > 0 || msg.OldRelayToAddr > 0 {
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v = cert.Version1
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b := [4]byte{}
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binary.BigEndian.PutUint32(b[:], msg.OldRelayFromAddr)
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msg.RelayFromAddr = netAddrToProtoAddr(netip.AddrFrom4(b))
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binary.BigEndian.PutUint32(b[:], msg.OldRelayToAddr)
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msg.RelayToAddr = netAddrToProtoAddr(netip.AddrFrom4(b))
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} else {
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v = cert.Version2
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}
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switch msg.Type {
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case NebulaControl_CreateRelayRequest:
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rm.handleCreateRelayRequest(v, h, f, msg)
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case NebulaControl_CreateRelayResponse:
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rm.handleCreateRelayResponse(v, h, f, msg)
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}
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}
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func (rm *relayManager) handleCreateRelayResponse(v cert.Version, h *HostInfo, f *Interface, m *NebulaControl) {
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rm.l.Info("handleCreateRelayResponse",
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"relayFrom", protoAddrToNetAddr(m.RelayFromAddr),
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"relayTo", protoAddrToNetAddr(m.RelayToAddr),
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"initiatorRelayIndex", m.InitiatorRelayIndex,
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"responderRelayIndex", m.ResponderRelayIndex,
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"vpnAddrs", h.vpnAddrs,
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)
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target := m.RelayToAddr
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targetAddr := protoAddrToNetAddr(target)
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relay, err := rm.EstablishRelay(h, m)
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if err != nil {
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rm.l.Error("Failed to update relay for relayTo", "error", err)
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return
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}
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// Do I need to complete the relays now?
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if relay.Type == TerminalType {
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return
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}
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// I'm the middle man. Let the initiator know that the I've established the relay they requested.
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peerHostInfo := rm.hostmap.QueryVpnAddr(relay.PeerAddr)
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if peerHostInfo == nil {
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rm.l.Error("Can't find a HostInfo for peer", "relayTo", relay.PeerAddr)
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return
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}
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peerRelay, ok := peerHostInfo.relayState.QueryRelayForByIp(targetAddr)
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if !ok {
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rm.l.Error("peerRelay does not have Relay state for relayTo", "relayTo", peerHostInfo.vpnAddrs[0])
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return
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}
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switch peerRelay.State {
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case Requested:
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// I initiated the request to this peer, but haven't heard back from the peer yet. I must wait for this peer
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// to respond to complete the connection.
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case PeerRequested, Disestablished, Established:
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peerHostInfo.relayState.UpdateRelayForByIpState(targetAddr, Established)
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resp := NebulaControl{
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Type: NebulaControl_CreateRelayResponse,
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ResponderRelayIndex: peerRelay.LocalIndex,
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InitiatorRelayIndex: peerRelay.RemoteIndex,
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}
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if v == cert.Version1 {
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peer := peerHostInfo.vpnAddrs[0]
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if !peer.Is4() {
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rm.l.Error("Refusing to CreateRelayResponse for a v1 relay with an ipv6 address",
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"relayFrom", peer,
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"relayTo", target,
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"initiatorRelayIndex", resp.InitiatorRelayIndex,
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"responderRelayIndex", resp.ResponderRelayIndex,
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"vpnAddrs", peerHostInfo.vpnAddrs,
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)
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return
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}
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b := peer.As4()
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resp.OldRelayFromAddr = binary.BigEndian.Uint32(b[:])
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b = targetAddr.As4()
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resp.OldRelayToAddr = binary.BigEndian.Uint32(b[:])
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} else {
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resp.RelayFromAddr = netAddrToProtoAddr(peerHostInfo.vpnAddrs[0])
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resp.RelayToAddr = target
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}
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msg, err := resp.Marshal()
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if err != nil {
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rm.l.Error("relayManager Failed to marshal Control CreateRelayResponse message to create relay", "error", err)
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} else {
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f.SendMessageToHostInfo(header.Control, 0, peerHostInfo, msg, make([]byte, 12), make([]byte, mtu))
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rm.l.Info("send CreateRelayResponse",
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"relayFrom", resp.RelayFromAddr,
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"relayTo", resp.RelayToAddr,
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"initiatorRelayIndex", resp.InitiatorRelayIndex,
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"responderRelayIndex", resp.ResponderRelayIndex,
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"vpnAddrs", peerHostInfo.vpnAddrs,
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)
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}
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}
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}
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func (rm *relayManager) handleCreateRelayRequest(v cert.Version, h *HostInfo, f *Interface, m *NebulaControl) {
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from := protoAddrToNetAddr(m.RelayFromAddr)
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target := protoAddrToNetAddr(m.RelayToAddr)
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logMsg := rm.l.With(
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"relayFrom", from,
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"relayTo", target,
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"initiatorRelayIndex", m.InitiatorRelayIndex,
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"vpnAddrs", h.vpnAddrs,
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)
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logMsg.Info("handleCreateRelayRequest")
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// Is the source of the relay me? This should never happen, but did happen due to
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// an issue migrating relays over to newly re-handshaked host info objects.
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if f.myVpnAddrsTable.Contains(from) {
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logMsg.Error("Discarding relay request from myself", "myIP", from)
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return
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}
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// Is the target of the relay me?
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if f.myVpnAddrsTable.Contains(target) {
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existingRelay, ok := h.relayState.QueryRelayForByIp(from)
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if ok {
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switch existingRelay.State {
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case Requested:
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ok = h.relayState.CompleteRelayByIP(from, m.InitiatorRelayIndex)
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if !ok {
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logMsg.Error("Relay State not found")
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return
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}
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case Established:
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if existingRelay.RemoteIndex != m.InitiatorRelayIndex {
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// We got a brand new Relay request, because its index is different than what we saw before.
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// This should never happen. The peer should never change an index, once created.
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logMsg.Error("Existing relay mismatch with CreateRelayRequest",
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"existingRemoteIndex", existingRelay.RemoteIndex)
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return
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}
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case Disestablished:
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if existingRelay.RemoteIndex != m.InitiatorRelayIndex {
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// We got a brand new Relay request, because its index is different than what we saw before.
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// This should never happen. The peer should never change an index, once created.
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logMsg.Error("Existing relay mismatch with CreateRelayRequest",
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"existingRemoteIndex", existingRelay.RemoteIndex)
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return
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}
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// Mark the relay as 'Established' because it's safe to use again
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h.relayState.UpdateRelayForByIpState(from, Established)
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case PeerRequested:
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// I should never be in this state, because I am terminal, not forwarding.
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logMsg.Error("Unexpected Relay State found",
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"existingRemoteIndex", existingRelay.RemoteIndex,
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"state", existingRelay.State)
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}
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} else {
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_, err := AddRelay(rm.l, h, f.hostMap, from, &m.InitiatorRelayIndex, TerminalType, Established)
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if err != nil {
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logMsg.Error("Failed to add relay", "error", err)
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return
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}
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}
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relay, ok := h.relayState.QueryRelayForByIp(from)
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if !ok {
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logMsg.Error("Relay State not found", "from", from)
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return
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}
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resp := NebulaControl{
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Type: NebulaControl_CreateRelayResponse,
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ResponderRelayIndex: relay.LocalIndex,
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InitiatorRelayIndex: relay.RemoteIndex,
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}
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if v == cert.Version1 {
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b := from.As4()
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resp.OldRelayFromAddr = binary.BigEndian.Uint32(b[:])
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b = target.As4()
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resp.OldRelayToAddr = binary.BigEndian.Uint32(b[:])
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} else {
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resp.RelayFromAddr = netAddrToProtoAddr(from)
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resp.RelayToAddr = netAddrToProtoAddr(target)
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}
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msg, err := resp.Marshal()
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if err != nil {
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logMsg.Error("relayManager Failed to marshal Control CreateRelayResponse message to create relay", "error", err)
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} else {
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f.SendMessageToHostInfo(header.Control, 0, h, msg, make([]byte, 12), make([]byte, mtu))
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rm.l.Info("send CreateRelayResponse",
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"relayFrom", from,
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"relayTo", target,
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"initiatorRelayIndex", resp.InitiatorRelayIndex,
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"responderRelayIndex", resp.ResponderRelayIndex,
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"vpnAddrs", h.vpnAddrs,
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)
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}
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return
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} else {
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// the target is not me. Create a relay to the target, from me.
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if !rm.GetAmRelay() {
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return
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}
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peer := rm.hostmap.QueryVpnAddr(target)
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if peer == nil {
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// Try to establish a connection to this host. If we get a future relay request,
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// we'll be ready!
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f.Handshake(target)
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return
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}
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if !peer.remote.IsValid() {
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// Only create relays to peers for whom I have a direct connection
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return
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}
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var index uint32
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var err error
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targetRelay, ok := peer.relayState.QueryRelayForByIp(from)
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if ok {
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index = targetRelay.LocalIndex
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} else {
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// Allocate an index in the hostMap for this relay peer
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index, err = AddRelay(rm.l, peer, f.hostMap, from, nil, ForwardingType, Requested)
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if err != nil {
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return
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}
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}
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peer.relayState.UpdateRelayForByIpState(from, Requested)
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// Send a CreateRelayRequest to the peer.
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req := NebulaControl{
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Type: NebulaControl_CreateRelayRequest,
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InitiatorRelayIndex: index,
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}
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if v == cert.Version1 {
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if !h.vpnAddrs[0].Is4() {
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rm.l.Error("Refusing to CreateRelayRequest for a v1 relay with an ipv6 address",
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"relayFrom", h.vpnAddrs[0],
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"relayTo", target,
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"initiatorRelayIndex", req.InitiatorRelayIndex,
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"responderRelayIndex", req.ResponderRelayIndex,
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"vpnAddr", target,
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)
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return
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}
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b := h.vpnAddrs[0].As4()
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req.OldRelayFromAddr = binary.BigEndian.Uint32(b[:])
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b = target.As4()
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req.OldRelayToAddr = binary.BigEndian.Uint32(b[:])
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} else {
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req.RelayFromAddr = netAddrToProtoAddr(h.vpnAddrs[0])
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req.RelayToAddr = netAddrToProtoAddr(target)
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}
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msg, err := req.Marshal()
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if err != nil {
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logMsg.Error("relayManager Failed to marshal Control message to create relay", "error", err)
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} else {
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f.SendMessageToHostInfo(header.Control, 0, peer, msg, make([]byte, 12), make([]byte, mtu))
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rm.l.Info("send CreateRelayRequest",
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"relayFrom", h.vpnAddrs[0],
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"relayTo", target,
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"initiatorRelayIndex", req.InitiatorRelayIndex,
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"responderRelayIndex", req.ResponderRelayIndex,
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"vpnAddr", target,
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)
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}
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// Also track the half-created Relay state just received
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_, ok = h.relayState.QueryRelayForByIp(target)
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if !ok {
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_, err := AddRelay(rm.l, h, f.hostMap, target, &m.InitiatorRelayIndex, ForwardingType, PeerRequested)
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if err != nil {
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logMsg.Error("relayManager Failed to allocate a local index for relay", "error", err)
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return
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}
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}
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}
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}
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