From 191e0c35c658acdaeed6ceea33cae0a04c6e672f Mon Sep 17 00:00:00 2001
From: Cole Brown <bigswim@gmail.com>
Date: Thu, 18 Oct 2018 18:07:49 -0400
Subject: [PATCH] Implement FindPeersConnectedToPeer

---
 p2pclient/dht.go | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

diff --git a/p2pclient/dht.go b/p2pclient/dht.go
index 3383c06..d77723b 100644
--- a/p2pclient/dht.go
+++ b/p2pclient/dht.go
@@ -21,6 +21,10 @@ type PeerInfo struct {
 }
 
 func convertPbPeerInfo(pbi *pb.PeerInfo) (*PeerInfo, error) {
+	if pbi == nil {
+		return nil, errors.New("null peerinfo")
+	}
+
 	id, err := peer.IDFromBytes(pbi.GetId())
 	if err != nil {
 		return nil, err
@@ -87,7 +91,7 @@ func (c *Client) FindPeer(peer peer.ID) (*PeerInfo, error) {
 		return nil, err
 	}
 
-	out := make(chan PeerInfo, 10)
+	out := make(chan *PeerInfo, 10)
 	defer close(out)
 	defer control.Close()
 
@@ -124,3 +128,44 @@ func (c *Client) FindPeer(peer peer.ID) (*PeerInfo, error) {
 
 	return info, nil
 }
+
+// FindPeersConnectedToPeer queries the DHT for peers that have an active
+// connection to a given peer.
+func (c *Client) FindPeersConnectedToPeer(ctx context.Context, peer peer.ID) (<-chan *PeerInfo, error) {
+	control, err := c.newControlConn()
+	if err != nil {
+		return nil, err
+	}
+
+	out := make(chan *PeerInfo, 10)
+	w := ggio.NewDelimitedWriter(control)
+	req := newDHTReq(&pb.DHTRequest{
+		Type: pb.DHTRequest_FIND_PEERS_CONNECTED_TO_PEER.Enum(),
+		Peer: []byte(peer),
+	})
+
+	if err := w.WriteMsg(req); err != nil {
+		return nil, err
+	}
+
+	go func() {
+		defer close(out)
+		respc := readDhtResponseStream(ctx, control)
+
+		for resp := range respc {
+			if resp.GetType() != pb.Response_OK {
+				log.Errorf("error from daemon in findpeersconnectedtopeer: %s", resp.GetError().GetMsg())
+				return
+			}
+
+			info, err := convertPbPeerInfo(resp.Dht.GetPeer())
+			if err != nil {
+				continue
+			}
+
+			out <- info
+		}
+	}()
+
+	return out, nil
+}