peer: allow external testing of peer.Peer

The previous use of allowSelfConns prevented this, as users aren't able
to invoke peer.TstAllowSelfConns themselves due to being part of a test
file, which aren't exported at the library level, leading to a
"disconnecting peer connected to self" error upon establishing a mock
connection between two peers. By including the option at the config
level instead (false by default, prevents connections to self) we enable
users of the peer library to properly test the behavior of the peer.Peer
struct externally.

peer/example_test.go

@@ -25,6 +25,7 @@ func mockRemotePeer() error {
 		UserAgentVersion: "1.0.0", // User agent version to advertise.
 		ChainParams:      &chaincfg.SimNetParams,
 		TrickleInterval:  time.Second * 10,
+		AllowSelfConns:   true,
 	}
 
 	// Accept connections on the simnet port.
@@ -81,6 +82,7 @@ func Example_newOutboundPeer() {
 				verack <- struct{}{}
 			},
 		},
+		AllowSelfConns: true,
 	}
 	p, err := peer.NewOutboundPeer(peerCfg, "127.0.0.1:18555")
 	if err != nil {

peer/export_test.go

@@ -1,18 +0,0 @@
-// Copyright (c) 2015 The btcsuite developers
-// Use of this source code is governed by an ISC
-// license that can be found in the LICENSE file.
-
-/*
-This test file is part of the peer package rather than than the peer_test
-package so it can bridge access to the internals to properly test cases which
-are either not possible or can't reliably be tested via the public interface.
-The functions are only exported while the tests are being run.
-*/
-
-package peer
-
-// TstAllowSelfConns allows the test package to allow self connections by
-// disabling the detection logic.
-func TstAllowSelfConns() {
-	allowSelfConns = true
-}

peer/peer.go

@@ -84,11 +84,6 @@ var (
 	// sentNonces houses the unique nonces that are generated when pushing
 	// version messages that are used to detect self connections.
 	sentNonces = lru.NewCache(50)
-
-	// allowSelfConns is only used to allow the tests to bypass the self
-	// connection detecting and disconnect logic since they intentionally
-	// do so for testing purposes.
-	allowSelfConns bool
 )
 
 // MessageListeners defines callback function pointers to invoke with message
@@ -276,6 +271,11 @@ type Config struct {
 	// TrickleInterval is the duration of the ticker which trickles down the
 	// inventory to a peer.
 	TrickleInterval time.Duration
+
+	// AllowSelfConns is only used to allow the tests to bypass the self
+	// connection detecting and disconnect logic since they intentionally
+	// do so for testing purposes.
+	AllowSelfConns bool
 }
 
 // minUint32 is a helper function to return the minimum of two uint32s.
@@ -1896,7 +1896,7 @@ func (p *Peer) readRemoteVersionMsg() error {
 	}
 
 	// Detect self connections.
-	if !allowSelfConns && sentNonces.Contains(msg.Nonce) {
+	if !p.cfg.AllowSelfConns && sentNonces.Contains(msg.Nonce) {
 		return errors.New("disconnecting peer connected to self")
 	}
 

peer/peer_test.go

@@ -238,6 +238,7 @@ func TestPeerConnection(t *testing.T) {
 		ProtocolVersion:   wire.RejectVersion, // Configure with older version
 		Services:          0,
 		TrickleInterval:   time.Second * 10,
+		AllowSelfConns:    true,
 	}
 	peer2Cfg := &peer.Config{
 		Listeners:         peer1Cfg.Listeners,
@@ -247,6 +248,7 @@ func TestPeerConnection(t *testing.T) {
 		ChainParams:       &chaincfg.MainNetParams,
 		Services:          wire.SFNodeNetwork | wire.SFNodeWitness,
 		TrickleInterval:   time.Second * 10,
+		AllowSelfConns:    true,
 	}
 
 	wantStats1 := peerStats{
@@ -452,6 +454,7 @@ func TestPeerListeners(t *testing.T) {
 		ChainParams:       &chaincfg.MainNetParams,
 		Services:          wire.SFNodeBloom,
 		TrickleInterval:   time.Second * 10,
+		AllowSelfConns:    true,
 	}
 	inConn, outConn := pipe(
 		&conn{raddr: "10.0.0.1:8333"},
@@ -623,6 +626,7 @@ func TestOutboundPeer(t *testing.T) {
 		ChainParams:       &chaincfg.MainNetParams,
 		Services:          0,
 		TrickleInterval:   time.Second * 10,
+		AllowSelfConns:    true,
 	}
 
 	r, w := io.Pipe()
@@ -764,6 +768,7 @@ func TestUnsupportedVersionPeer(t *testing.T) {
 		ChainParams:       &chaincfg.MainNetParams,
 		Services:          0,
 		TrickleInterval:   time.Second * 10,
+		AllowSelfConns:    true,
 	}
 
 	localNA := wire.NewNetAddressIPPort(
@@ -874,6 +879,7 @@ func TestDuplicateVersionMsg(t *testing.T) {
 		UserAgentVersion: "1.0",
 		ChainParams:      &chaincfg.MainNetParams,
 		Services:         0,
+		AllowSelfConns:   true,
 	}
 	inConn, outConn := pipe(
 		&conn{laddr: "10.0.0.1:9108", raddr: "10.0.0.2:9108"},
@@ -935,6 +941,7 @@ func TestUpdateLastBlockHeight(t *testing.T) {
 		UserAgentVersion: "1.0",
 		ChainParams:      &chaincfg.MainNetParams,
 		Services:         0,
+		AllowSelfConns:   true,
 	}
 	remotePeerCfg := peerCfg
 	remotePeerCfg.NewestBlock = func() (*chainhash.Hash, int32, error) {
@@ -982,8 +989,3 @@ func TestUpdateLastBlockHeight(t *testing.T) {
 			remotePeerHeight+1)
 	}
 }
-
-func init() {
-	// Allow self connection when running the tests.
-	peer.TstAllowSelfConns()
-}