addrmgr: Add convenient new functions.

This commit creates two new functions: EncodeHost and
NewNetAddressFromParams. The goal is to allow easier creation of net
addresses without needing to resort to DNS lookups. DNS lookups will be
removed from addrmgr.

addrmgr/addrmanager.go

@@ -738,6 +738,23 @@ func (a *AddrManager) reset() {
 	}
 }
 
+// EncodeHost attemps to identify the given host address as a supported network
+// address type, converts it to a unique encoding based on that type, and
+// returns the result.  If the host string is not recognized as any known type,
+// then an unknown address type is returned without error.
+func EncodeHost(host string) (NetAddressType, []byte) {
+	// Look for IPv4 or IPv6 addresses
+	if ip := net.ParseIP(host); ip != nil {
+		if isIPv4(ip) {
+			return IPv4Address, ip.To4()
+		}
+		return IPv6Address, ip
+	}
+
+	// The given host address could not be recognized
+	return UnknownAddressType, nil
+}
+
 // HostToNetAddress parses and returns a network address given a hostname in a
 // supported format (IPv4, IPv6).  If the hostname cannot be immediately
 // converted from a known address format, it will be resolved using the lookup
@@ -746,19 +763,22 @@ func (a *AddrManager) reset() {
 //
 // This function is safe for concurrent access.
 func (a *AddrManager) HostToNetAddress(host string, port uint16, services wire.ServiceFlag) (*NetAddress, error) {
-	var ip net.IP
-	if ip = net.ParseIP(host); ip == nil {
-		ips, err := a.lookupFunc(host)
-		if err != nil {
-			return nil, err
-		}
-		if len(ips) == 0 {
-			return nil, fmt.Errorf("no addresses found for %s", host)
-		}
-		ip = ips[0]
+	addrType, addrBytes := EncodeHost(host)
+	if addrType != UnknownAddressType {
+		// Since the host type has been successfully recognized and encoded,
+		// there is no need to perform a DNS lookup.
+		now := time.Unix(time.Now().Unix(), 0)
+		return NewNetAddressFromParams(addrType, addrBytes, port, now, services)
 	}
-
-	return NewNetAddressFromIPPort(ip, port, services), nil
+	// Cannot determine the host address type. Must use DNS.
+	ips, err := a.lookupFunc(host)
+	if err != nil {
+		return nil, err
+	}
+	if len(ips) == 0 {
+		return nil, fmt.Errorf("no addresses found for %s", host)
+	}
+	return NewNetAddressFromIPPort(ips[0], port, services), nil
 }
 
 // GetAddress returns a single address that should be routable.  It picks a

addrmgr/error.go

@@ -18,6 +18,10 @@ const (
 	// ErrUnknownAddressType indicates that the network address type could not
 	// be determined from a network address' bytes.
 	ErrUnknownAddressType = ErrorKind("ErrUnknownAddressType")
+
+	// ErrMismatchedAddressType indicates that a network address was expected to
+	// be a certain type, but the derived type does not match.
+	ErrMismatchedAddressType = ErrorKind("ErrMismatchedAddressType")
 )
 
 // Error satisfies the error interface and prints human-readable errors.

addrmgr/error_test.go

@@ -25,6 +25,11 @@ func TestErrors(t *testing.T) {
 		errorKind:   ErrUnknownAddressType,
 		description: "unknown address type",
 		wantErr:     ErrUnknownAddressType,
+	}, {
+		name:        "ErrMismatchedAddressType",
+		errorKind:   ErrMismatchedAddressType,
+		description: "mismatched address type",
+		wantErr:     ErrMismatchedAddressType,
 	}}
 
 	for _, test := range tests {

addrmgr/netaddress.go

@@ -112,9 +112,42 @@ func canonicalizeIP(addrType NetAddressType, addrBytes []byte) []byte {
 	return addrBytes
 }
 
-// newNetAddressFromString creates a new address manager network address from the
-// provided string.  The address is expected to be provided in the format
-// host:port.
+// checkNetAddressType returns an error if the suggested address type does not
+// appear to match the provided address.
+func checkNetAddressType(addrType NetAddressType, addrBytes []byte) error {
+	derivedAddressType, err := deriveNetAddressType(addrBytes)
+	if err != nil {
+		return err
+	}
+	if addrType != derivedAddressType {
+		str := fmt.Sprintf("derived address type does not match expected value"+
+			" (got %v, expected %v, address bytes %v).", derivedAddressType,
+			addrType, addrBytes)
+		return makeError(ErrMismatchedAddressType, str)
+	}
+	return nil
+}
+
+// NewNetAddressFromParams creates a new network address from the given
+// parameters. If the provided address type does not appear to match the
+// address, an error is returned.
+func NewNetAddressFromParams(netAddressType NetAddressType, addrBytes []byte, port uint16, timestamp time.Time, services wire.ServiceFlag) (*NetAddress, error) {
+	canonicalizedIP := canonicalizeIP(netAddressType, addrBytes)
+	err := checkNetAddressType(netAddressType, canonicalizedIP)
+	if err != nil {
+		return nil, err
+	}
+	return &NetAddress{
+		Type:      netAddressType,
+		IP:        canonicalizedIP,
+		Port:      port,
+		Services:  services,
+		Timestamp: timestamp,
+	}, nil
+}
+
+// newNetAddressFromString creates a new network address from the given string.
+// The address string is expected to be provided in the format "host:port".
 func (a *AddrManager) newNetAddressFromString(addr string) (*NetAddress, error) {
 	host, portStr, err := net.SplitHostPort(addr)
 	if err != nil {
@@ -124,8 +157,14 @@ func (a *AddrManager) newNetAddressFromString(addr string) (*NetAddress, error)
 	if err != nil {
 		return nil, err
 	}
-
-	return a.HostToNetAddress(host, uint16(port), wire.SFNodeNetwork)
+	addrType, addrBytes := EncodeHost(host)
+	if addrType == UnknownAddressType {
+		str := fmt.Sprintf("failed to deserialize address %s", addr)
+		return nil, makeError(ErrUnknownAddressType, str)
+	}
+	timestamp := time.Unix(time.Now().Unix(), 0)
+	return NewNetAddressFromParams(addrType, addrBytes, uint16(port), timestamp,
+		wire.SFNodeNetwork)
 }
 
 // NewNetAddressFromIPPort creates a new network address given an ip, port, and

addrmgr/netaddress_test.go

@@ -103,10 +103,19 @@ func TestKey(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		netAddr := NewNetAddressFromIPPort(net.ParseIP(test.ip), test.port, wire.SFNodeNetwork)
+		host_ip := test.ip
+		addrType, addrBytes := EncodeHost(host_ip)
+
+		netAddr, err := NewNetAddressFromParams(addrType, addrBytes, test.port,
+			time.Now(), wire.SFNodeNetwork)
+		if err != nil {
+			t.Fatalf("failed to construct net address from host %q: %v",
+				host_ip, err)
+		}
+
 		key := netAddr.Key()
 		if key != test.want {
-			t.Errorf("unexpected network address key -- got %s, want %s",
+			t.Errorf("unexpected network address key -- got %q, want %q",
 				key, test.want)
 			continue
 		}
@@ -142,6 +151,96 @@ func TestAddService(t *testing.T) {
 	}
 }
 
+// TestNewNetAddressFromParams verifies that the NewNetAddressFromParams
+// constructor correctly creates a network address with expected field values.
+func TestNewNetAddressFromParams(t *testing.T) {
+	const port = 8345
+	const services = wire.SFNodeNetwork
+	timestamp := time.Unix(time.Now().Unix(), 0)
+
+	tests := []struct {
+		name           string
+		addrType       NetAddressType
+		addrBytes      []byte
+		want           *NetAddress
+		error_expected bool
+	}{
+		{
+			name:      "4 byte ipv4 address stored as 4 byte ip",
+			addrType:  IPv4Address,
+			addrBytes: net.ParseIP("127.0.0.1").To4(),
+			want: &NetAddress{
+				IP:        []byte{0x7f, 0x00, 0x00, 0x01},
+				Port:      port,
+				Services:  services,
+				Timestamp: timestamp,
+				Type:      IPv4Address,
+			},
+			error_expected: false,
+		},
+		{
+			name:      "16 byte ipv4 address stored as 4 byte ip",
+			addrType:  IPv4Address,
+			addrBytes: net.ParseIP("127.0.0.1").To16(),
+			want: &NetAddress{
+				IP:        []byte{0x7f, 0x00, 0x00, 0x01},
+				Port:      port,
+				Services:  services,
+				Timestamp: timestamp,
+				Type:      IPv4Address,
+			},
+			error_expected: false,
+		},
+		{
+			name:      "16 byte ipv6 address stored in 16 bytes",
+			addrType:  IPv6Address,
+			addrBytes: net.ParseIP("::1"),
+			want: &NetAddress{
+				IP: []byte{
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01},
+				Port:      port,
+				Services:  services,
+				Timestamp: timestamp,
+				Type:      IPv6Address,
+			},
+			error_expected: false,
+		},
+		{
+			name:           "Error: Cannot derive net address type",
+			addrType:       UnknownAddressType,
+			addrBytes:      []byte{0x01, 0x02, 0x03},
+			want:           nil,
+			error_expected: true,
+		},
+		{
+			name:           "Error: the provided type doesn't match the bytes",
+			addrType:       IPv6Address,
+			addrBytes:      net.ParseIP("127.0.0.1").To4(),
+			want:           nil,
+			error_expected: true,
+		},
+		{
+			name:           "Error: no address bytes were provided",
+			addrType:       UnknownAddressType,
+			addrBytes:      nil,
+			want:           nil,
+			error_expected: true,
+		}}
+
+	for _, test := range tests {
+		addr, err := NewNetAddressFromParams(test.addrType, test.addrBytes,
+			port, timestamp, services)
+		if err != nil && test.error_expected == false {
+			t.Fatalf("%q: unexpected error - %v", test.name, err)
+		}
+		if !reflect.DeepEqual(addr, test.want) {
+			t.Errorf("%q: mismatched entries\ngot  %+v\nwant %+v", test.name,
+				addr, test.want)
+		}
+	}
+}
+
 // TestNewNetAddressFromString verifies that the newNetAddressFromString
 // constructor correctly creates a network address with expected field values.
 func TestNewNetAddressFromString(t *testing.T) {