Don't drop connections when simultaneous dialing occurs

go.sum

@@ -107,6 +107,7 @@ github.com/libp2p/go-conn-security-multistream v0.1.0/go.mod h1:aw6eD7LOsHEX7+2h
 github.com/libp2p/go-flow-metrics v0.0.1 h1:0gxuFd2GuK7IIP5pKljLwps6TvcuYgvG7Atqi3INF5s=
 github.com/libp2p/go-flow-metrics v0.0.1/go.mod h1:Iv1GH0sG8DtYN3SVJ2eG221wMiNpZxBdp967ls1g+k8=
 github.com/libp2p/go-flow-metrics v0.0.2/go.mod h1:HeoSNUrOJVK1jEpDqVEiUOIXqhbnS27omG0uWU5slZs=
+github.com/libp2p/go-flow-metrics v0.0.3 h1:8tAs/hSdNvUiLgtlSy3mxwxWP4I9y/jlkPFT7epKdeM=
 github.com/libp2p/go-flow-metrics v0.0.3/go.mod h1:HeoSNUrOJVK1jEpDqVEiUOIXqhbnS27omG0uWU5slZs=
 github.com/libp2p/go-libp2p-core v0.0.1 h1:HSTZtFIq/W5Ue43Zw+uWZyy2Vl5WtF0zDjKN8/DT/1I=
 github.com/libp2p/go-libp2p-core v0.0.1/go.mod h1:g/VxnTZ/1ygHxH3dKok7Vno1VfpvGcGip57wjTU4fco=
@@ -291,6 +292,7 @@ github.com/xordataexchange/crypt v0.0.3-0.20170626215501-b2862e3d0a77/go.mod h1:
 go.opencensus.io v0.21.0 h1:mU6zScU4U1YAFPHEHYk+3JC4SY7JxgkqS10ZOSyksNg=
 go.opencensus.io v0.21.0/go.mod h1:mSImk1erAIZhrmZN+AvHh14ztQfjbGwt4TtuofqLduU=
 go.opencensus.io v0.22.1/go.mod h1:Ap50jQcDJrx6rB6VgeeFPtuPIf3wMRvRfrfYDO6+BmA=
+go.opencensus.io v0.22.2 h1:75k/FF0Q2YM8QYo07VPddOLBslDt1MZOdEslOHvmzAs=
 go.opencensus.io v0.22.2/go.mod h1:yxeiOL68Rb0Xd1ddK5vPZ/oVn4vY4Ynel7k9FzqtOIw=
 golang.org/x/crypto v0.0.0-20170930174604-9419663f5a44/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=

swarm.go

@@ -230,7 +230,9 @@ func (s *Swarm) addConn(tc transport.CapableConn, dir network.Direction) (*Conn,
 
 	// We have a connection now. Cancel all other in-progress dials.
 	// This should be fast, no reason to wait till later.
-	s.dsync.CancelDial(p)
+	if dir == network.DirOutbound {
+		s.dsync.CancelDial(p)
+	}
 
 	s.notifyAll(func(f network.Notifiee) {
 		f.Connected(s, c)