Add holepunching stats and tests

[btrtrc.git] / peerconn.go

diff --git a/peerconn.go b/peerconn.go
index 1163ad7740d6143278fe8cc02681222e71925a90..1443a7b9a7afaf7fe86c4f8ea9247b367c8cd0a9 100644 (file)
--- a/peerconn.go
+++ b/peerconn.go
@@ -9,15 +9,18 @@ import (
        "io"
        "math/rand"
        "net"
+       "net/netip"
        "strconv"
        "strings"
        "time"
 
        "github.com/RoaringBitmap/roaring"
+       "github.com/anacrolix/generics"
        . "github.com/anacrolix/generics"
        "github.com/anacrolix/log"
        "github.com/anacrolix/missinggo/v2/bitmap"
        "github.com/anacrolix/multiless"
+       "golang.org/x/exp/maps"
        "golang.org/x/time/rate"
 
        "github.com/anacrolix/torrent/bencode"
@@ -25,6 +28,7 @@ import (
        "github.com/anacrolix/torrent/metainfo"
        "github.com/anacrolix/torrent/mse"
        pp "github.com/anacrolix/torrent/peer_protocol"
+       utHolepunch "github.com/anacrolix/torrent/peer_protocol/ut-holepunch"
 )
 
 // Maintains the state of a BitTorrent-protocol based connection with a peer.
@@ -38,6 +42,7 @@ type PeerConn struct {
        // See BEP 3 etc.
        PeerID             PeerID
        PeerExtensionBytes pp.PeerExtensionBits
+       PeerListenPort     int
 
        // The actual Conn, used for closing, and setting socket options. Do not use methods on this
        // while holding any mutexes.
@@ -59,22 +64,48 @@ type PeerConn struct {
        peerSentHaveAll bool
 
        peerRequestDataAllocLimiter alloclim.Limiter
+
+       outstandingHolepunchingRendezvous map[netip.AddrPort]struct{}
+}
+
+func (cn *PeerConn) pexStatus() string {
+       if !cn.bitExtensionEnabled(pp.ExtensionBitLtep) {
+               return "extended protocol disabled"
+       }
+       if cn.PeerExtensionIDs == nil {
+               return "pending extended handshake"
+       }
+       if !cn.supportsExtension(pp.ExtensionNamePex) {
+               return "unsupported"
+       }
+       if true {
+               return fmt.Sprintf(
+                       "%v conns, %v unsent events",
+                       len(cn.pex.remoteLiveConns),
+                       cn.pex.numPending(),
+               )
+       } else {
+               // This alternative branch prints out the remote live conn addresses.
+               return fmt.Sprintf(
+                       "%v conns, %v unsent events",
+                       strings.Join(generics.SliceMap(
+                               maps.Keys(cn.pex.remoteLiveConns),
+                               func(from netip.AddrPort) string {
+                                       return from.String()
+                               }), ","),
+                       cn.pex.numPending(),
+               )
+
+       }
 }
 
 func (cn *PeerConn) peerImplStatusLines() []string {
-       lines := make([]string, 0, 2)
-       lines = append(
-               lines,
-               fmt.Sprintf("%+-55q %v %s", cn.PeerID, cn.PeerExtensionBytes, cn.connString))
-       if cn.supportsExtension(pp.ExtensionNamePex) {
-               lines = append(
-                       lines,
-                       fmt.Sprintf(
-                               "pex: %v conns, %v unsent events",
-                               cn.pex.remoteLiveConns,
-                               cn.pex.numPending()))
+       return []string{
+               cn.connString,
+               fmt.Sprintf("peer id: %+q", cn.PeerID),
+               fmt.Sprintf("extensions: %v", cn.PeerExtensionBytes),
+               fmt.Sprintf("pex: %s", cn.pexStatus()),
        }
-       return lines
 }
 
 // Returns true if the connection is over IPv6.
@@ -86,10 +117,12 @@ func (cn *PeerConn) ipv6() bool {
        return len(ip) == net.IPv6len
 }
 
-// Returns true the if the dialer/initiator has the lower client peer ID. TODO: Find the
-// specification for this.
+// Returns true the if the dialer/initiator has the higher client peer ID. See
+// https://github.com/arvidn/libtorrent/blame/272828e1cc37b042dfbbafa539222d8533e99755/src/bt_peer_connection.cpp#L3536-L3557.
+// As far as I can tell, Transmission just keeps the oldest connection.
 func (cn *PeerConn) isPreferredDirection() bool {
-       return bytes.Compare(cn.t.cl.peerID[:], cn.PeerID[:]) < 0 == cn.outgoing
+       // True if our client peer ID is higher than the remote's peer ID.
+       return bytes.Compare(cn.PeerID[:], cn.t.cl.peerID[:]) < 0 == cn.outgoing
 }
 
 // Returns whether the left connection should be preferred over the right one,
@@ -879,6 +912,15 @@ func (c *PeerConn) onReadExtendedMsg(id pp.ExtensionNumber, payload []byte) (err
                        err = fmt.Errorf("receiving pex message: %w", err)
                }
                return
+       case utHolepunchExtendedId:
+               var msg utHolepunch.Msg
+               err = msg.UnmarshalBinary(payload)
+               if err != nil {
+                       err = fmt.Errorf("unmarshalling ut_holepunch message: %w", err)
+                       return
+               }
+               err = c.t.handleReceivedUtHolepunchMsg(msg, c)
+               return
        default:
                return fmt.Errorf("unexpected extended message ID: %v", id)
        }
@@ -1024,6 +1066,8 @@ func (c *PeerConn) dialAddr() PeerRemoteAddr {
                        dialAddr := *addr
                        dialAddr.Port = c.PeerListenPort
                        return &dialAddr
+               default:
+                       panic(addr)
                }
        }
        return c.RemoteAddr
@@ -1050,3 +1094,18 @@ func (cn *PeerConn) PeerPieces() *roaring.Bitmap {
 func (pc *PeerConn) remoteIsTransmission() bool {
        return bytes.HasPrefix(pc.PeerID[:], []byte("-TR")) && pc.PeerID[7] == '-'
 }
+
+func (pc *PeerConn) remoteAddrPort() Option[netip.AddrPort] {
+       return Some(pc.conn.RemoteAddr().(interface {
+               AddrPort() netip.AddrPort
+       }).AddrPort())
+}
+
+func (pc *PeerConn) remoteDialAddrPort() (netip.AddrPort, error) {
+       dialAddr := pc.dialAddr()
+       return addrPortFromPeerRemoteAddr(dialAddr)
+}
+
+func (pc *PeerConn) bitExtensionEnabled(bit pp.ExtensionBit) bool {
+       return pc.t.cl.config.Extensions.GetBit(bit) && pc.PeerExtensionBytes.GetBit(bit)
+}