forked from libp2p/go-libp2p-circuit
/
relay.go
395 lines (315 loc) · 8.74 KB
/
relay.go
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package relay
import (
"context"
"fmt"
"io"
"sync"
"time"
pb "github.com/libp2p/go-libp2p-circuit/pb"
logging "github.com/ipfs/go-log"
host "github.com/libp2p/go-libp2p-host"
inet "github.com/libp2p/go-libp2p-net"
peer "github.com/libp2p/go-libp2p-peer"
pstore "github.com/libp2p/go-libp2p-peerstore"
tptu "github.com/libp2p/go-libp2p-transport-upgrader"
ma "github.com/multiformats/go-multiaddr"
)
var log = logging.Logger("relay")
const ProtoID = "/libp2p/circuit/relay/0.1.0"
const maxMessageSize = 4096
var RelayAcceptTimeout = time.Minute
var HopConnectTimeout = 10 * time.Second
type Relay struct {
host host.Host
upgrader *tptu.Upgrader
ctx context.Context
self peer.ID
active bool
hop bool
incoming chan *Conn
relays map[peer.ID]struct{}
mx sync.Mutex
}
type RelayOpt int
var (
OptActive = RelayOpt(0)
OptHop = RelayOpt(1)
)
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)
}
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
default:
return nil, fmt.Errorf("unrecognized option: %d", opt)
}
}
h.SetStreamHandler(ProtoID, r.handleNewStream)
h.Network().Notify(r.Notifiee())
return r, nil
}
func (r *Relay) DialPeer(ctx context.Context, relay pstore.PeerInfo, dest pstore.PeerInfo) (*Conn, error) {
log.Debugf("dialing peer %s through relay %s", dest.ID, relay.ID)
if len(relay.Addrs) > 0 {
r.host.Peerstore().AddAddrs(relay.ID, relay.Addrs, pstore.TempAddrTTL)
}
s, err := r.host.NewStream(ctx, relay.ID, ProtoID)
if err != nil {
return nil, err
}
rd := newDelimitedReader(s, maxMessageSize)
wr := newDelimitedWriter(s)
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()}
}
return &Conn{Stream: s, remote: dest}, 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
}
func (r *Relay) CanHop(ctx context.Context, id peer.ID) (bool, error) {
s, err := r.host.NewStream(ctx, id, ProtoID)
if err != nil {
return false, err
}
rd := newDelimitedReader(s, maxMessageSize)
wr := newDelimitedWriter(s)
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
}
if err := inet.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) handleNewStream(s inet.Stream) {
log.Infof("new relay stream from: %s", s.Conn().RemotePeer())
rd := newDelimitedReader(s, maxMessageSize)
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)
}
}
func (r *Relay) handleHopStream(s inet.Stream, msg *pb.CircuitRelay) {
if !r.hop {
r.handleError(s, pb.CircuitRelay_HOP_CANT_SPEAK_RELAY)
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
ctp := r.host.Network().ConnsToPeer(dst.ID)
if len(ctp) == 0 && !r.active {
r.handleError(s, pb.CircuitRelay_HOP_NO_CONN_TO_DST)
return
}
if len(dst.Addrs) > 0 {
r.host.Peerstore().AddAddrs(dst.ID, dst.Addrs, pstore.TempAddrTTL)
}
ctx, cancel := context.WithTimeout(r.ctx, HopConnectTimeout)
defer cancel()
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())
r.handleError(s, pb.CircuitRelay_HOP_CANT_DIAL_DST)
return
}
// stop handshake
rd := newDelimitedReader(bs, maxMessageSize)
wr := newDelimitedWriter(bs)
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())
// Don't reset streams after finishing or the other side will get an
// error, not an EOF.
go func() {
count, err := io.Copy(s, bs)
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() {
count, err := io.Copy(bs, s)
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())
}()
}
func (r *Relay) handleStopStream(s inet.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 {
r.host.Peerstore().AddAddrs(src.ID, src.Addrs, pstore.TempAddrTTL)
}
select {
case r.incoming <- &Conn{Stream: s, remote: src}:
case <-time.After(RelayAcceptTimeout):
r.handleError(s, pb.CircuitRelay_STOP_RELAY_REFUSED)
}
}
func (r *Relay) handleCanHop(s inet.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 {
inet.FullClose(s)
}
}
func (r *Relay) handleError(s inet.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 {
inet.FullClose(s)
}
}
func (r *Relay) writeResponse(s inet.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)
}