p2p: fix ports handling, add test cases

p2p/enode/node_test.go

@@ -74,6 +74,7 @@ func TestNodeEndpoints(t *testing.T) {
 		wantUDP  int
 		wantTCP  int
 		wantQUIC int
+		wantDNS  string
 	}
 	tests := []endpointTest{
 		{
@@ -268,6 +269,54 @@ func TestNodeEndpoints(t *testing.T) {
 			wantIP:   netip.MustParseAddr("2001::ff00:0042:8329"),
 			wantQUIC: 9001,
 		},
+		{
+			name: "dns-only",
+			node: func() *Node {
+				var r enr.Record
+				n := SignNull(&r, id)
+				n.dnsName = "example.com"
+				n.tcp = 30303
+				n.udp = 30303
+				return n
+			}(),
+			wantTCP: 30303,
+			wantUDP: 30303,
+			wantDNS: "example.com",
+		},
+		{
+			name: "dns-with-ports",
+			node: func() *Node {
+				var r enr.Record
+				r.Set(enr.TCP(9000))
+				r.Set(enr.UDP(9001))
+				n := SignNull(&r, id)
+				n.dnsName = "node.example.org"
+				n.tcp = 9000
+				n.udp = 9001
+				return n
+			}(),
+			wantTCP: 9000,
+			wantUDP: 9001,
+			wantDNS: "node.example.org",
+		},
+		{
+			name: "dns-with-ip-fallback",
+			node: func() *Node {
+				var r enr.Record
+				r.Set(enr.IPv4Addr(netip.MustParseAddr("192.168.1.1")))
+				r.Set(enr.TCP(9000))
+				r.Set(enr.UDP(9000))
+				n := SignNull(&r, id)
+				n.dnsName = "node.example.org"
+				n.tcp = 9000
+				n.udp = 9000
+				return n
+			}(),
+			wantIP:  netip.MustParseAddr("192.168.1.1"),
+			wantTCP: 9000,
+			wantUDP: 9000,
+			wantDNS: "node.example.org",
+		},
 	}
 
 	for _, test := range tests {
@@ -284,6 +333,9 @@ func TestNodeEndpoints(t *testing.T) {
 			if quic, _ := test.node.QUICEndpoint(); test.wantQUIC != int(quic.Port()) {
 				t.Errorf("node has wrong QUIC port %d, want %d", quic.Port(), test.wantQUIC)
 			}
+			if test.wantDNS != test.node.DNSName() {
+				t.Errorf("node has wrong DNS name %s, want %s", test.node.DNSName(), test.wantDNS)
+			}
 		})
 	}
 }

p2p/enode/urlv4.go

@@ -101,6 +101,32 @@ func NewV4(pubkey *ecdsa.PublicKey, ip net.IP, tcp, udp int) *Node {
 	return n
 }
 
+func NewV4WithDNS(pubkey *ecdsa.PublicKey, ip net.IP, dnsName string, tcp, udp int) *Node {
+	var r enr.Record
+	if len(ip) > 0 {
+		r.Set(enr.IP(ip))
+	}
+	// Always set TCP/UDP ports regardless of IP
+	// This is to ensure that the node is always
+	// considered valid even if the IP is not
+	// set.
+	if tcp != 0 {
+		r.Set(enr.TCP(tcp))
+	}
+	if udp != 0 {
+		r.Set(enr.UDP(udp))
+	}
+	signV4Compat(&r, pubkey)
+	n, err := New(v4CompatID{}, &r)
+	if err != nil {
+		panic(err)
+	}
+	n.dnsName = dnsName
+	n.tcp = uint16(tcp)
+	n.udp = uint16(udp)
+	return n
+}
+
 // isNewV4 returns true for nodes created by NewV4.
 func isNewV4(n *Node) bool {
 	var k s256raw
@@ -139,16 +165,18 @@ func parseComplete(rawurl string) (*Node, error) {
 	}
 	// Check if hostname is an IP address and create node accordingly
 	hostname := u.Hostname()
-	if ip := net.ParseIP(hostname); ip != nil {
-		// Create node with IP
-		node := NewV4(id, ip, int(tcpPort), int(udpPort))
-		return node, nil
+	ip := net.ParseIP(hostname)
+	if ip == nil {
+		ips, err := lookupIPFunc(hostname)
+		if err != nil {
+			return NewV4WithDNS(id, nil, hostname, int(tcpPort), int(udpPort)), nil
 		}
-
-	// Create node for DNS name
-	node := NewV4(id, nil, int(tcpPort), int(udpPort))
-	node.dnsName = hostname
-	return node, nil
+		ip = ips[0]
+	}
+	if ipv4 := ip.To4(); ipv4 != nil {
+		ip = ipv4
+	}
+	return NewV4(id, ip, int(tcpPort), int(udpPort)), nil
 }
 
 // parsePubkey parses a hex-encoded secp256k1 public key.
@@ -178,13 +206,13 @@ func (n *Node) URLv4() string {
 		nodeid = fmt.Sprintf("%s.%x", scheme, n.id[:])
 	}
 	u := url.URL{Scheme: "enode"}
-	if !n.ip.IsValid() {
+	if !n.ip.IsValid() && n.dnsName == "" {
 		u.Host = nodeid
-	} else {
+		return u.String()
+	}
 	u.User = url.User(nodeid)
-		// Use DNS name if available, otherwise use IP
-		if n.DNSName() != "" {
-			u.Host = fmt.Sprintf("%s:%d", n.DNSName(), n.TCP())
+	if n.dnsName != "" {
+		u.Host = fmt.Sprintf("%s:%d", n.dnsName, n.TCP())
 	} else {
 		addr := net.TCPAddr{IP: n.IP(), Port: n.TCP()}
 		u.Host = addr.String()
@@ -192,7 +220,6 @@ func (n *Node) URLv4() string {
 	if n.UDP() != n.TCP() {
 		u.RawQuery = "discport=" + strconv.Itoa(n.UDP())
 	}
-	}
 	return u.String()
 }
 

p2p/enode/urlv4_test.go

@@ -70,10 +70,6 @@ var parseNodeTests = []struct {
 		wantError: enr.ErrInvalidSig.Error(),
 	},
 	// Complete node URLs with IP address and ports
-	{
-		input:     "enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@invalid.:3",
-		wantError: `no such host`,
-	},
 	{
 		input:     "enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@127.0.0.1:foo",
 		wantError: `invalid port`,
@@ -82,6 +78,16 @@ var parseNodeTests = []struct {
 		input:     "enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@127.0.0.1:3?discport=foo",
 		wantError: `invalid discport in query`,
 	},
+	{
+		input: "enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@valid.:3",
+		wantResult: NewV4WithDNS(
+			hexPubkey("1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
+			nil,
+			"valid.",
+			3,
+			3,
+		),
+	},
 	{
 		input: "enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@127.0.0.1:52150",
 		wantResult: NewV4(