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svc.go
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svc.go
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package autonat
import (
"context"
"errors"
"math/rand"
"net"
"sync"
"time"
"github.com/ipfs/fs-repo-migrations/ipfs-10-to-11/_vendor/github.com/libp2p/go-libp2p-core/network"
"github.com/ipfs/fs-repo-migrations/ipfs-10-to-11/_vendor/github.com/libp2p/go-libp2p-core/peer"
"github.com/ipfs/fs-repo-migrations/ipfs-10-to-11/_vendor/github.com/libp2p/go-libp2p-core/peerstore"
pb "github.com/ipfs/fs-repo-migrations/ipfs-10-to-11/_vendor/github.com/libp2p/go-libp2p-autonat/pb"
"github.com/ipfs/fs-repo-migrations/ipfs-10-to-11/_vendor/github.com/libp2p/go-msgio/protoio"
ma "github.com/ipfs/fs-repo-migrations/ipfs-10-to-11/_vendor/github.com/multiformats/go-multiaddr"
manet "github.com/ipfs/fs-repo-migrations/ipfs-10-to-11/_vendor/github.com/multiformats/go-multiaddr/net"
)
// AutoNATService provides NAT autodetection services to other peers
type autoNATService struct {
ctx context.Context
instance context.CancelFunc
instanceLock sync.Mutex
config *config
// rate limiter
running uint32
mx sync.Mutex
reqs map[peer.ID]int
globalReqs int
}
// NewAutoNATService creates a new AutoNATService instance attached to a host
func newAutoNATService(ctx context.Context, c *config) (*autoNATService, error) {
if c.dialer == nil {
return nil, errors.New("Cannot create NAT service without a network")
}
as := &autoNATService{
ctx: ctx,
config: c,
reqs: make(map[peer.ID]int),
}
return as, nil
}
func (as *autoNATService) handleStream(s network.Stream) {
defer s.Close()
pid := s.Conn().RemotePeer()
log.Debugf("New stream from %s", pid.Pretty())
r := protoio.NewDelimitedReader(s, network.MessageSizeMax)
w := protoio.NewDelimitedWriter(s)
var req pb.Message
var res pb.Message
err := r.ReadMsg(&req)
if err != nil {
log.Debugf("Error reading message from %s: %s", pid.Pretty(), err.Error())
s.Reset()
return
}
t := req.GetType()
if t != pb.Message_DIAL {
log.Debugf("Unexpected message from %s: %s (%d)", pid.Pretty(), t.String(), t)
s.Reset()
return
}
dr := as.handleDial(pid, s.Conn().RemoteMultiaddr(), req.GetDial().GetPeer())
res.Type = pb.Message_DIAL_RESPONSE.Enum()
res.DialResponse = dr
err = w.WriteMsg(&res)
if err != nil {
log.Debugf("Error writing response to %s: %s", pid.Pretty(), err.Error())
s.Reset()
return
}
}
func (as *autoNATService) handleDial(p peer.ID, obsaddr ma.Multiaddr, mpi *pb.Message_PeerInfo) *pb.Message_DialResponse {
if mpi == nil {
return newDialResponseError(pb.Message_E_BAD_REQUEST, "missing peer info")
}
mpid := mpi.GetId()
if mpid != nil {
mp, err := peer.IDFromBytes(mpid)
if err != nil {
return newDialResponseError(pb.Message_E_BAD_REQUEST, "bad peer id")
}
if mp != p {
return newDialResponseError(pb.Message_E_BAD_REQUEST, "peer id mismatch")
}
}
addrs := make([]ma.Multiaddr, 0, as.config.maxPeerAddresses)
seen := make(map[string]struct{})
// add observed addr to the list of addresses to dial
var obsHost net.IP
if !as.config.dialPolicy.skipDial(obsaddr) {
addrs = append(addrs, obsaddr)
seen[obsaddr.String()] = struct{}{}
obsHost, _ = manet.ToIP(obsaddr)
}
for _, maddr := range mpi.GetAddrs() {
addr, err := ma.NewMultiaddrBytes(maddr)
if err != nil {
log.Debugf("Error parsing multiaddr: %s", err.Error())
continue
}
if as.config.dialPolicy.skipDial(addr) {
continue
}
if ip, err := manet.ToIP(addr); err != nil || !obsHost.Equal(ip) {
continue
}
str := addr.String()
_, ok := seen[str]
if ok {
continue
}
addrs = append(addrs, addr)
seen[str] = struct{}{}
if len(addrs) >= as.config.maxPeerAddresses {
break
}
}
if len(addrs) == 0 {
return newDialResponseError(pb.Message_E_DIAL_ERROR, "no dialable addresses")
}
return as.doDial(peer.AddrInfo{ID: p, Addrs: addrs})
}
func (as *autoNATService) doDial(pi peer.AddrInfo) *pb.Message_DialResponse {
// rate limit check
as.mx.Lock()
count := as.reqs[pi.ID]
if count >= as.config.throttlePeerMax || (as.config.throttleGlobalMax > 0 &&
as.globalReqs >= as.config.throttleGlobalMax) {
as.mx.Unlock()
return newDialResponseError(pb.Message_E_DIAL_REFUSED, "too many dials")
}
as.reqs[pi.ID] = count + 1
as.globalReqs++
as.mx.Unlock()
ctx, cancel := context.WithTimeout(as.ctx, as.config.dialTimeout)
defer cancel()
as.config.dialer.Peerstore().ClearAddrs(pi.ID)
as.config.dialer.Peerstore().AddAddrs(pi.ID, pi.Addrs, peerstore.TempAddrTTL)
conn, err := as.config.dialer.DialPeer(ctx, pi.ID)
if err != nil {
log.Debugf("error dialing %s: %s", pi.ID.Pretty(), err.Error())
// wait for the context to timeout to avoid leaking timing information
// this renders the service ineffective as a port scanner
<-ctx.Done()
return newDialResponseError(pb.Message_E_DIAL_ERROR, "dial failed")
}
ra := conn.RemoteMultiaddr()
as.config.dialer.ClosePeer(pi.ID)
return newDialResponseOK(ra)
}
// Enable the autoNAT service if it is not running.
func (as *autoNATService) Enable() {
as.instanceLock.Lock()
defer as.instanceLock.Unlock()
if as.instance != nil {
return
}
inst, cncl := context.WithCancel(as.ctx)
as.instance = cncl
go as.background(inst)
}
// Disable the autoNAT service if it is running.
func (as *autoNATService) Disable() {
as.instanceLock.Lock()
defer as.instanceLock.Unlock()
if as.instance != nil {
as.instance()
as.instance = nil
}
}
func (as *autoNATService) background(ctx context.Context) {
as.config.host.SetStreamHandler(AutoNATProto, as.handleStream)
timer := time.NewTimer(as.config.throttleResetPeriod)
defer timer.Stop()
for {
select {
case <-timer.C:
as.mx.Lock()
as.reqs = make(map[peer.ID]int)
as.globalReqs = 0
as.mx.Unlock()
jitter := rand.Float32() * float32(as.config.throttleResetJitter)
timer.Reset(as.config.throttleResetPeriod + time.Duration(int64(jitter)))
case <-ctx.Done():
as.config.host.RemoveStreamHandler(AutoNATProto)
return
}
}
}