X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=pexconn.go;h=9254f5e1876c15ceff293d9f37c687d004d73b5c;hb=HEAD;hp=d0308f756db44ddc9d134842f7f85ed5521fa529;hpb=4a06517856eff49efa03e9f6c550aa1baeb35500;p=btrtrc.git

diff --git a/pexconn.go b/pexconn.go
index d0308f75..9254f5e1 100644
--- a/pexconn.go
+++ b/pexconn.go
@@ -2,8 +2,10 @@ package torrent
 
 import (
 	"fmt"
+	"net/netip"
 	"time"
 
+	g "github.com/anacrolix/generics"
 	"github.com/anacrolix/log"
 
 	pp "github.com/anacrolix/torrent/peer_protocol"
@@ -26,6 +28,9 @@ type pexConnState struct {
 	Listed  bool
 	info    log.Logger
 	dbg     log.Logger
+	// Running record of live connections the remote end of the connection purports to have.
+	remoteLiveConns map[netip.AddrPort]g.Option[pp.PexPeerFlags]
+	lastRecv        time.Time
 }
 
 func (s *pexConnState) IsEnabled() bool {
@@ -67,6 +72,13 @@ func (s *pexConnState) genmsg() *pp.PexMsg {
 	return &tx
 }
 
+func (s *pexConnState) numPending() int {
+	if s.torrent == nil {
+		return 0
+	}
+	return s.torrent.pex.numPending(s.last)
+}
+
 // Share is called from the writer goroutine if when it is woken up with the write buffers empty
 // Returns whether there's more room on the send buffer to write to.
 func (s *pexConnState) Share(postfn messageWriter) bool {
@@ -86,36 +98,63 @@ func (s *pexConnState) Share(postfn messageWriter) bool {
 	return true
 }
 
-// Recv is called from the reader goroutine
-func (s *pexConnState) Recv(payload []byte) error {
-	if !s.torrent.wantPeers() {
-		s.dbg.Printf("peer reserve ok, incoming PEX discarded")
-		return nil
+func (s *pexConnState) updateRemoteLiveConns(rx pp.PexMsg) (errs []error) {
+	for _, dropped := range rx.Dropped {
+		addrPort, _ := ipv4AddrPortFromKrpcNodeAddr(dropped)
+		delete(s.remoteLiveConns, addrPort)
 	}
-	if time.Now().Before(s.torrent.pex.rest) {
-		s.dbg.Printf("in cooldown period, incoming PEX discarded")
-		return nil
+	for _, dropped := range rx.Dropped6 {
+		addrPort, _ := ipv6AddrPortFromKrpcNodeAddr(dropped)
+		delete(s.remoteLiveConns, addrPort)
+	}
+	for i, added := range rx.Added {
+		addr := netip.AddrFrom4(*(*[4]byte)(added.IP.To4()))
+		addrPort := netip.AddrPortFrom(addr, uint16(added.Port))
+		flags := g.SliceGet(rx.AddedFlags, i)
+		g.MakeMapIfNilAndSet(&s.remoteLiveConns, addrPort, flags)
+	}
+	for i, added := range rx.Added6 {
+		addr := netip.AddrFrom16(*(*[16]byte)(added.IP.To16()))
+		addrPort := netip.AddrPortFrom(addr, uint16(added.Port))
+		flags := g.SliceGet(rx.Added6Flags, i)
+		g.MakeMapIfNilAndSet(&s.remoteLiveConns, addrPort, flags)
 	}
+	return
+}
 
+// Recv is called from the reader goroutine
+func (s *pexConnState) Recv(payload []byte) error {
 	rx, err := pp.LoadPexMsg(payload)
 	if err != nil {
-		return fmt.Errorf("error unmarshalling PEX message: %s", err)
+		return fmt.Errorf("unmarshalling pex message: %w", err)
 	}
-	s.dbg.Print("incoming PEX message: ", rx)
+	s.dbg.Printf("received pex message: %v", rx)
 	torrent.Add("pex added peers received", int64(len(rx.Added)))
 	torrent.Add("pex added6 peers received", int64(len(rx.Added6)))
 
+	// "Clients must batch updates to send no more than 1 PEX message per minute."
+	timeSinceLastRecv := time.Since(s.lastRecv)
+	if timeSinceLastRecv < 45*time.Second {
+		return fmt.Errorf("last received only %v ago", timeSinceLastRecv)
+	}
+	s.lastRecv = time.Now()
+	s.updateRemoteLiveConns(rx)
+
 	var peers peerInfos
 	peers.AppendFromPex(rx.Added6, rx.Added6Flags)
 	peers.AppendFromPex(rx.Added, rx.AddedFlags)
-	s.dbg.Printf("adding %d peers from PEX", len(peers))
+	if time.Now().Before(s.torrent.pex.rest) {
+		s.dbg.Printf("in cooldown period, incoming PEX discarded")
+		return nil
+	}
+	added := s.torrent.addPeers(peers)
+	s.dbg.Printf("got %v peers over pex, added %v", len(peers), added)
+
 	if len(peers) > 0 {
 		s.torrent.pex.rest = time.Now().Add(pexInterval)
-		s.torrent.addPeers(peers)
 	}
 
 	// one day we may also want to:
-	// - check if the peer is not flooding us with PEX updates
 	// - handle drops somehow
 	// - detect malicious peers