Send v2 upgrade bit

diff --git a/client.go b/client.go
index 64b053fce260741095b2da51cc4bde2a9cb05d8d..ed1a0c714c85fb382af45cde52ebdcf2d07d0b1d 100644 (file)
--- a/client.go
+++ b/client.go
@@ -927,7 +927,12 @@ func (cl *Client) initiateHandshakes(c *PeerConn, t *Torrent) (err error) {
                        return fmt.Errorf("header obfuscation handshake: %w", err)
                }
        }
-       ih, err := cl.connBtHandshake(c, t.canonicalShortInfohash())
+       localReservedBits := cl.config.Extensions
+       handshakeIh := *t.canonicalShortInfohash()
+       // If we're sending the v1 infohash, and we know the v2 infohash, set the v2 upgrade bit. This
+       // means the peer can send the v2 infohash in the handshake to upgrade the connection.
+       localReservedBits.SetBit(pp.ExtensionBitV2Upgrade, g.Some(handshakeIh) == t.infoHash && t.infoHashV2.Ok)
+       ih, err := cl.connBtHandshake(c, &handshakeIh, localReservedBits)
        if err != nil {
                return fmt.Errorf("bittorrent protocol handshake: %w", err)
        }
@@ -935,6 +940,7 @@ func (cl *Client) initiateHandshakes(c *PeerConn, t *Torrent) (err error) {
                return nil
        }
        if t.infoHashV2.Ok && *t.infoHashV2.Value.ToShort() == ih {
+               torrent.Add("initiated handshakes upgraded to v2", 1)
                c.v2 = true
                return nil
        }
@@ -1004,7 +1010,7 @@ func (cl *Client) receiveHandshakes(c *PeerConn) (t *Torrent, err error) {
                err = errors.New("connection does not have required header obfuscation")
                return
        }
-       ih, err := cl.connBtHandshake(c, nil)
+       ih, err := cl.connBtHandshake(c, nil, cl.config.Extensions)
        if err != nil {
                return nil, fmt.Errorf("during bt handshake: %w", err)
        }
@@ -1022,8 +1028,8 @@ func init() {
                &successfulPeerWireProtocolHandshakePeerReservedBytes)
 }
 
-func (cl *Client) connBtHandshake(c *PeerConn, ih *metainfo.Hash) (ret metainfo.Hash, err error) {
-       res, err := pp.Handshake(c.rw(), ih, cl.peerID, cl.config.Extensions)
+func (cl *Client) connBtHandshake(c *PeerConn, ih *metainfo.Hash, reservedBits PeerExtensionBits) (ret metainfo.Hash, err error) {
+       res, err := pp.Handshake(c.rw(), ih, cl.peerID, reservedBits)
        if err != nil {
                return
        }