status-go/vendor/github.com/libp2p/go-libp2p-circuit/relay.go

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package relay
import (
"context"
"fmt"
"io"
"sync"
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"sync/atomic"
"time"
pb "github.com/libp2p/go-libp2p-circuit/pb"
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"github.com/libp2p/go-libp2p-core/helpers"
"github.com/libp2p/go-libp2p-core/host"
"github.com/libp2p/go-libp2p-core/network"
"github.com/libp2p/go-libp2p-core/peer"
"github.com/libp2p/go-libp2p-core/peerstore"
pool "github.com/libp2p/go-buffer-pool"
tptu "github.com/libp2p/go-libp2p-transport-upgrader"
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logging "github.com/ipfs/go-log"
ma "github.com/multiformats/go-multiaddr"
)
var log = logging.Logger("relay")
const ProtoID = "/libp2p/circuit/relay/0.1.0"
const maxMessageSize = 4096
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var (
RelayAcceptTimeout = 10 * time.Second
HopConnectTimeout = 30 * time.Second
StopHandshakeTimeout = 1 * time.Minute
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HopStreamBufferSize = 4096
HopStreamLimit = 1 << 19 // 512K hops for 1M goroutines
)
// Relay is the relay transport and service.
type Relay struct {
host host.Host
upgrader *tptu.Upgrader
ctx context.Context
self peer.ID
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active bool
hop bool
discovery bool
incoming chan *Conn
relays map[peer.ID]struct{}
mx sync.Mutex
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// atomic counters
streamCount int32
liveHopCount int32
}
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// RelayOpts are options for configuring the relay transport.
type RelayOpt int
var (
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// OptActive configures the relay transport to actively establish
// outbound connections on behalf of clients. You probably don't want to
// enable this unless you know what you're doing.
OptActive = RelayOpt(0)
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// OptHop configures the relay transport to accept requests to relay
// traffic on behalf of third-parties. Unless OptActive is specified,
// this will only relay traffic between peers already connected to this
// node.
OptHop = RelayOpt(1)
// OptDiscovery configures this relay transport to discover new relays
// by probing every new peer. You almost _certainly_ don't want to
// enable this.
OptDiscovery = RelayOpt(2)
)
type RelayError struct {
Code pb.CircuitRelay_Status
}
func (e RelayError) Error() string {
return fmt.Sprintf("error opening relay circuit: %s (%d)", pb.CircuitRelay_Status_name[int32(e.Code)], e.Code)
}
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// NewRelay constructs a new relay.
func NewRelay(ctx context.Context, h host.Host, upgrader *tptu.Upgrader, opts ...RelayOpt) (*Relay, error) {
r := &Relay{
upgrader: upgrader,
host: h,
ctx: ctx,
self: h.ID(),
incoming: make(chan *Conn),
relays: make(map[peer.ID]struct{}),
}
for _, opt := range opts {
switch opt {
case OptActive:
r.active = true
case OptHop:
r.hop = true
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case OptDiscovery:
r.discovery = true
default:
return nil, fmt.Errorf("unrecognized option: %d", opt)
}
}
h.SetStreamHandler(ProtoID, r.handleNewStream)
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if r.discovery {
h.Network().Notify(r.notifiee())
}
return r, nil
}
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// Increment the live hop count and increment the connection manager tags by 1 for the two
// sides of the hop stream. This ensures that connections with many hop streams will be protected
// from pruning, thus minimizing disruption from connection trimming in a relay node.
func (r *Relay) addLiveHop(from, to peer.ID) {
atomic.AddInt32(&r.liveHopCount, 1)
r.host.ConnManager().UpsertTag(from, "relay-hop-stream", incrementTag)
r.host.ConnManager().UpsertTag(to, "relay-hop-stream", incrementTag)
}
// Decrement the live hpo count and decrement the connection manager tags for the two sides
// of the hop stream.
func (r *Relay) rmLiveHop(from, to peer.ID) {
atomic.AddInt32(&r.liveHopCount, -1)
r.host.ConnManager().UpsertTag(from, "relay-hop-stream", decrementTag)
r.host.ConnManager().UpsertTag(to, "relay-hop-stream", decrementTag)
}
func (r *Relay) GetActiveHops() int32 {
return atomic.LoadInt32(&r.liveHopCount)
}
func (r *Relay) DialPeer(ctx context.Context, relay peer.AddrInfo, dest peer.AddrInfo) (*Conn, error) {
log.Debugf("dialing peer %s through relay %s", dest.ID, relay.ID)
if len(relay.Addrs) > 0 {
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r.host.Peerstore().AddAddrs(relay.ID, relay.Addrs, peerstore.TempAddrTTL)
}
s, err := r.host.NewStream(ctx, relay.ID, ProtoID)
if err != nil {
return nil, err
}
rd := newDelimitedReader(s, maxMessageSize)
wr := newDelimitedWriter(s)
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defer rd.Close()
var msg pb.CircuitRelay
msg.Type = pb.CircuitRelay_HOP.Enum()
msg.SrcPeer = peerInfoToPeer(r.host.Peerstore().PeerInfo(r.self))
msg.DstPeer = peerInfoToPeer(dest)
err = wr.WriteMsg(&msg)
if err != nil {
s.Reset()
return nil, err
}
msg.Reset()
err = rd.ReadMsg(&msg)
if err != nil {
s.Reset()
return nil, err
}
if msg.GetType() != pb.CircuitRelay_STATUS {
s.Reset()
return nil, fmt.Errorf("unexpected relay response; not a status message (%d)", msg.GetType())
}
if msg.GetCode() != pb.CircuitRelay_SUCCESS {
s.Reset()
return nil, RelayError{msg.GetCode()}
}
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return &Conn{stream: s, remote: dest, host: r.host}, nil
}
func (r *Relay) Matches(addr ma.Multiaddr) bool {
// TODO: Look at the prefix transport as well.
_, err := addr.ValueForProtocol(P_CIRCUIT)
return err == nil
}
// Queries a peer for support of hop relay
func CanHop(ctx context.Context, host host.Host, id peer.ID) (bool, error) {
s, err := host.NewStream(ctx, id, ProtoID)
if err != nil {
return false, err
}
rd := newDelimitedReader(s, maxMessageSize)
wr := newDelimitedWriter(s)
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defer rd.Close()
var msg pb.CircuitRelay
msg.Type = pb.CircuitRelay_CAN_HOP.Enum()
if err := wr.WriteMsg(&msg); err != nil {
s.Reset()
return false, err
}
msg.Reset()
if err := rd.ReadMsg(&msg); err != nil {
s.Reset()
return false, err
}
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if err := helpers.FullClose(s); err != nil {
return false, err
}
if msg.GetType() != pb.CircuitRelay_STATUS {
return false, fmt.Errorf("unexpected relay response; not a status message (%d)", msg.GetType())
}
return msg.GetCode() == pb.CircuitRelay_SUCCESS, nil
}
func (r *Relay) CanHop(ctx context.Context, id peer.ID) (bool, error) {
return CanHop(ctx, r.host, id)
}
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func (r *Relay) handleNewStream(s network.Stream) {
log.Infof("new relay stream from: %s", s.Conn().RemotePeer())
rd := newDelimitedReader(s, maxMessageSize)
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defer rd.Close()
var msg pb.CircuitRelay
err := rd.ReadMsg(&msg)
if err != nil {
r.handleError(s, pb.CircuitRelay_MALFORMED_MESSAGE)
return
}
switch msg.GetType() {
case pb.CircuitRelay_HOP:
r.handleHopStream(s, &msg)
case pb.CircuitRelay_STOP:
r.handleStopStream(s, &msg)
case pb.CircuitRelay_CAN_HOP:
r.handleCanHop(s, &msg)
default:
log.Warningf("unexpected relay handshake: %d", msg.GetType())
r.handleError(s, pb.CircuitRelay_MALFORMED_MESSAGE)
}
}
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func (r *Relay) handleHopStream(s network.Stream, msg *pb.CircuitRelay) {
if !r.hop {
r.handleError(s, pb.CircuitRelay_HOP_CANT_SPEAK_RELAY)
return
}
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streamCount := atomic.AddInt32(&r.streamCount, 1)
liveHopCount := atomic.LoadInt32(&r.liveHopCount)
defer atomic.AddInt32(&r.streamCount, -1)
if (streamCount + liveHopCount) > int32(HopStreamLimit) {
log.Warning("hop stream limit exceeded; resetting stream")
s.Reset()
return
}
src, err := peerToPeerInfo(msg.GetSrcPeer())
if err != nil {
r.handleError(s, pb.CircuitRelay_HOP_SRC_MULTIADDR_INVALID)
return
}
if src.ID != s.Conn().RemotePeer() {
r.handleError(s, pb.CircuitRelay_HOP_SRC_MULTIADDR_INVALID)
return
}
dst, err := peerToPeerInfo(msg.GetDstPeer())
if err != nil {
r.handleError(s, pb.CircuitRelay_HOP_DST_MULTIADDR_INVALID)
return
}
if dst.ID == r.self {
r.handleError(s, pb.CircuitRelay_HOP_CANT_RELAY_TO_SELF)
return
}
// open stream
ctx, cancel := context.WithTimeout(r.ctx, HopConnectTimeout)
defer cancel()
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if !r.active {
ctx = network.WithNoDial(ctx, "relay hop")
} else if len(dst.Addrs) > 0 {
r.host.Peerstore().AddAddrs(dst.ID, dst.Addrs, peerstore.TempAddrTTL)
}
bs, err := r.host.NewStream(ctx, dst.ID, ProtoID)
if err != nil {
log.Debugf("error opening relay stream to %s: %s", dst.ID.Pretty(), err.Error())
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if err == network.ErrNoConn {
r.handleError(s, pb.CircuitRelay_HOP_NO_CONN_TO_DST)
} else {
r.handleError(s, pb.CircuitRelay_HOP_CANT_DIAL_DST)
}
return
}
// stop handshake
rd := newDelimitedReader(bs, maxMessageSize)
wr := newDelimitedWriter(bs)
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defer rd.Close()
// set handshake deadline
bs.SetDeadline(time.Now().Add(StopHandshakeTimeout))
msg.Type = pb.CircuitRelay_STOP.Enum()
err = wr.WriteMsg(msg)
if err != nil {
log.Debugf("error writing stop handshake: %s", err.Error())
bs.Reset()
r.handleError(s, pb.CircuitRelay_HOP_CANT_OPEN_DST_STREAM)
return
}
msg.Reset()
err = rd.ReadMsg(msg)
if err != nil {
log.Debugf("error reading stop response: %s", err.Error())
bs.Reset()
r.handleError(s, pb.CircuitRelay_HOP_CANT_OPEN_DST_STREAM)
return
}
if msg.GetType() != pb.CircuitRelay_STATUS {
log.Debugf("unexpected relay stop response: not a status message (%d)", msg.GetType())
bs.Reset()
r.handleError(s, pb.CircuitRelay_HOP_CANT_OPEN_DST_STREAM)
return
}
if msg.GetCode() != pb.CircuitRelay_SUCCESS {
log.Debugf("relay stop failure: %d", msg.GetCode())
bs.Reset()
r.handleError(s, msg.GetCode())
return
}
err = r.writeResponse(s, pb.CircuitRelay_SUCCESS)
if err != nil {
log.Debugf("error writing relay response: %s", err.Error())
bs.Reset()
s.Reset()
return
}
// relay connection
log.Infof("relaying connection between %s and %s", src.ID.Pretty(), dst.ID.Pretty())
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// reset deadline
bs.SetDeadline(time.Time{})
r.addLiveHop(src.ID, dst.ID)
goroutines := new(int32)
*goroutines = 2
done := func() {
if atomic.AddInt32(goroutines, -1) == 0 {
r.rmLiveHop(src.ID, dst.ID)
}
}
// Don't reset streams after finishing or the other side will get an
// error, not an EOF.
go func() {
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defer done()
buf := pool.Get(HopStreamBufferSize)
defer pool.Put(buf)
count, err := io.CopyBuffer(s, bs, buf)
if err != nil {
log.Debugf("relay copy error: %s", err)
// Reset both.
s.Reset()
bs.Reset()
} else {
// propagate the close
s.Close()
}
log.Debugf("relayed %d bytes from %s to %s", count, dst.ID.Pretty(), src.ID.Pretty())
}()
go func() {
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defer done()
buf := pool.Get(HopStreamBufferSize)
defer pool.Put(buf)
count, err := io.CopyBuffer(bs, s, buf)
if err != nil {
log.Debugf("relay copy error: %s", err)
// Reset both.
bs.Reset()
s.Reset()
} else {
// propagate the close
bs.Close()
}
log.Debugf("relayed %d bytes from %s to %s", count, src.ID.Pretty(), dst.ID.Pretty())
}()
}
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func (r *Relay) handleStopStream(s network.Stream, msg *pb.CircuitRelay) {
src, err := peerToPeerInfo(msg.GetSrcPeer())
if err != nil {
r.handleError(s, pb.CircuitRelay_STOP_SRC_MULTIADDR_INVALID)
return
}
dst, err := peerToPeerInfo(msg.GetDstPeer())
if err != nil || dst.ID != r.self {
r.handleError(s, pb.CircuitRelay_STOP_DST_MULTIADDR_INVALID)
return
}
log.Infof("relay connection from: %s", src.ID)
if len(src.Addrs) > 0 {
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r.host.Peerstore().AddAddrs(src.ID, src.Addrs, peerstore.TempAddrTTL)
}
select {
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case r.incoming <- &Conn{stream: s, remote: src, host: r.host}:
case <-time.After(RelayAcceptTimeout):
r.handleError(s, pb.CircuitRelay_STOP_RELAY_REFUSED)
}
}
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func (r *Relay) handleCanHop(s network.Stream, msg *pb.CircuitRelay) {
var err error
if r.hop {
err = r.writeResponse(s, pb.CircuitRelay_SUCCESS)
} else {
err = r.writeResponse(s, pb.CircuitRelay_HOP_CANT_SPEAK_RELAY)
}
if err != nil {
s.Reset()
log.Debugf("error writing relay response: %s", err.Error())
} else {
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helpers.FullClose(s)
}
}
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func (r *Relay) handleError(s network.Stream, code pb.CircuitRelay_Status) {
log.Warningf("relay error: %s (%d)", pb.CircuitRelay_Status_name[int32(code)], code)
err := r.writeResponse(s, code)
if err != nil {
s.Reset()
log.Debugf("error writing relay response: %s", err.Error())
} else {
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helpers.FullClose(s)
}
}
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func (r *Relay) writeResponse(s network.Stream, code pb.CircuitRelay_Status) error {
wr := newDelimitedWriter(s)
var msg pb.CircuitRelay
msg.Type = pb.CircuitRelay_STATUS.Enum()
msg.Code = code.Enum()
return wr.WriteMsg(&msg)
}