net: consoldate literal target address into IP address functions

This CL continues with introducing IPv6 scoped addressing capability
into the net package.

Update #4234.

R=rsc
CC=golang-dev
https://golang.org/cl/6842053

src/pkg/net/dial.go

@@ -15,6 +15,7 @@ func parseDialNetwork(net string) (afnet string, proto int, err error) {
 		switch net {
 		case "tcp", "tcp4", "tcp6":
 		case "udp", "udp4", "udp6":
+		case "ip", "ip4", "ip6":
 		case "unix", "unixgram", "unixpacket":
 		default:
 			return "", 0, UnknownNetworkError(net)
@@ -54,12 +55,8 @@ func resolveAfnetAddr(afnet, addr string, deadline time.Time) (Addr, error) {
 		return nil, nil
 	}
 	switch afnet {
-	case "tcp", "tcp4", "tcp6":
-		return resolveTCPAddr(afnet, addr, deadline)
-	case "udp", "udp4", "udp6":
-		return resolveUDPAddr(afnet, addr, deadline)
-	case "ip", "ip4", "ip6":
-		return resolveIPAddr(afnet, addr, deadline)
+	case "tcp", "tcp4", "tcp6", "udp", "udp4", "udp6", "ip", "ip4", "ip6":
+		return resolveInternetAddr(afnet, addr, deadline)
 	case "unix", "unixgram", "unixpacket":
 		return ResolveUnixAddr(afnet, addr)
 	}
@@ -218,8 +215,8 @@ func Listen(net, laddr string) (Listener, error) {
 // ListenPacket announces on the local network address laddr.
 // The network string net must be a packet-oriented network:
 // "udp", "udp4", "udp6", "ip", "ip4", "ip6" or "unixgram".
-func ListenPacket(net, addr string) (PacketConn, error) {
-	afnet, a, err := resolveNetAddr("listen", net, addr, noDeadline)
+func ListenPacket(net, laddr string) (PacketConn, error) {
+	afnet, a, err := resolveNetAddr("listen", net, laddr, noDeadline)
 	if err != nil {
 		return nil, err
 	}

src/pkg/net/ipraw_test.go

@@ -9,11 +9,43 @@ package net
 import (
 	"bytes"
 	"os"
+	"reflect"
 	"syscall"
 	"testing"
 	"time"
 )
 
+var resolveIPAddrTests = []struct {
+	net     string
+	litAddr string
+	addr    *IPAddr
+	err     error
+}{
+	{"ip", "127.0.0.1", &IPAddr{IP: IPv4(127, 0, 0, 1)}, nil},
+	{"ip4", "127.0.0.1", &IPAddr{IP: IPv4(127, 0, 0, 1)}, nil},
+	{"ip4:icmp", "127.0.0.1", &IPAddr{IP: IPv4(127, 0, 0, 1)}, nil},
+
+	{"ip", "::1", &IPAddr{IP: ParseIP("::1")}, nil},
+	{"ip6", "::1", &IPAddr{IP: ParseIP("::1")}, nil},
+	{"ip6:icmp", "::1", &IPAddr{IP: ParseIP("::1")}, nil},
+
+	{"l2tp", "127.0.0.1", nil, UnknownNetworkError("l2tp")},
+	{"l2tp:gre", "127.0.0.1", nil, UnknownNetworkError("l2tp:gre")},
+	{"tcp", "1.2.3.4:123", nil, UnknownNetworkError("tcp")},
+}
+
+func TestResolveIPAddr(t *testing.T) {
+	for _, tt := range resolveIPAddrTests {
+		addr, err := ResolveIPAddr(tt.net, tt.litAddr)
+		if err != tt.err {
+			t.Fatalf("ResolveIPAddr(%v, %v) failed: %v", tt.net, tt.litAddr, err)
+		}
+		if !reflect.DeepEqual(addr, tt.addr) {
+			t.Fatalf("got %#v; expected %#v", addr, tt.addr)
+		}
+	}
+}
+
 var icmpTests = []struct {
 	net   string
 	laddr string

src/pkg/net/iprawsock.go

@@ -6,10 +6,6 @@
 
 package net
 
-import (
-	"time"
-)
-
 // IPAddr represents the address of an IP end point.
 type IPAddr struct {
 	IP   IP
@@ -31,44 +27,15 @@ func (a *IPAddr) String() string {
 // "ip", "ip4" or "ip6".  A literal IPv6 host address must be
 // enclosed in square brackets, as in "[::]".
 func ResolveIPAddr(net, addr string) (*IPAddr, error) {
-	return resolveIPAddr(net, addr, noDeadline)
-}
-
-func resolveIPAddr(net, addr string, deadline time.Time) (*IPAddr, error) {
-	ip, err := hostToIP(net, addr, deadline)
+	afnet, _, err := parseDialNetwork(net)
 	if err != nil {
 		return nil, err
 	}
-	return &IPAddr{IP: ip}, nil
-}
-
-// Convert "host" into IP address.
-func hostToIP(net, host string, deadline time.Time) (ip IP, err error) {
-	var addr IP
-	// Try as an IP address.
-	addr = ParseIP(host)
-	if addr == nil {
-		filter := anyaddr
-		if net != "" && net[len(net)-1] == '4' {
-			filter = ipv4only
-		}
-		if net != "" && net[len(net)-1] == '6' {
-			filter = ipv6only
-		}
-		// Not an IP address.  Try as a DNS name.
-		addrs, err1 := lookupHostDeadline(host, deadline)
-		if err1 != nil {
-			err = err1
-			goto Error
-		}
-		addr = firstFavoriteAddr(filter, addrs)
-		if addr == nil {
-			// should not happen
-			err = &AddrError{"LookupHost returned no suitable address", addrs[0]}
-			goto Error
-		}
+	switch afnet {
+	case "ip", "ip4", "ip6":
+	default:
+		return nil, UnknownNetworkError(net)
 	}
-	return addr, nil
-Error:
-	return nil, err
+	a, err := resolveInternetAddr(afnet, addr, noDeadline)
+	return a.(*IPAddr), nil
 }

src/pkg/net/ipsock.go

@@ -72,15 +72,18 @@ func (e InvalidAddrError) Temporary() bool { return false }
 // "host:port" or "[host]:port" into host and port.
 // The latter form must be used when host contains a colon.
 func SplitHostPort(hostport string) (host, port string, err error) {
+	host, port, _, err = splitHostPort(hostport)
+	return
+}
+
+func splitHostPort(hostport string) (host, port, zone string, err error) {
 	// The port starts after the last colon.
 	i := last(hostport, ':')
 	if i < 0 {
 		err = &AddrError{"missing port in address", hostport}
 		return
 	}
-
-	host, port = hostport[0:i], hostport[i+1:]
-
+	host, port = hostport[:i], hostport[i+1:]
 	// Can put brackets around host ...
 	if len(host) > 0 && host[0] == '[' && host[len(host)-1] == ']' {
 		host = host[1 : len(host)-1]
@@ -104,44 +107,65 @@ func JoinHostPort(host, port string) string {
 	return host + ":" + port
 }
 
-// Convert "host:port" into IP address and port.
-func hostPortToIP(net, hostport string, deadline time.Time) (ip IP, iport int, err error) {
-	host, port, err := SplitHostPort(hostport)
-	if err != nil {
-		return nil, 0, err
-	}
-
-	var addr IP
-	if host != "" {
-		// Try as an IP address.
-		addr = ParseIP(host)
-		if addr == nil {
-			var filter func(IP) IP
-			if net != "" && net[len(net)-1] == '4' {
-				filter = ipv4only
-			}
-			if net != "" && net[len(net)-1] == '6' {
-				filter = ipv6only
-			}
-			// Not an IP address.  Try as a DNS name.
-			addrs, err := lookupHostDeadline(host, deadline)
-			if err != nil {
-				return nil, 0, err
+func resolveInternetAddr(net, addr string, deadline time.Time) (Addr, error) {
+	var (
+		err              error
+		host, port, zone string
+		portnum          int
+	)
+	switch net {
+	case "tcp", "tcp4", "tcp6", "udp", "udp4", "udp6":
+		if addr != "" {
+			if host, port, zone, err = splitHostPort(addr); err != nil {
+				return nil, err
 			}
-			addr = firstFavoriteAddr(filter, addrs)
-			if addr == nil {
-				// should not happen
-				return nil, 0, &AddrError{"LookupHost returned no suitable address", addrs[0]}
+			if portnum, err = parsePort(net, port); err != nil {
+				return nil, err
 			}
 		}
+	case "ip", "ip4", "ip6":
+		if addr != "" {
+			host = addr
+		}
+	default:
+		return nil, UnknownNetworkError(net)
 	}
-
-	p, err := parsePort(net, port)
+	inetaddr := func(net string, ip IP, port int, zone string) Addr {
+		switch net {
+		case "tcp", "tcp4", "tcp6":
+			return &TCPAddr{IP: ip, Port: port, Zone: zone}
+		case "udp", "udp4", "udp6":
+			return &UDPAddr{IP: ip, Port: port, Zone: zone}
+		case "ip", "ip4", "ip6":
+			return &IPAddr{IP: ip, Zone: zone}
+		}
+		return nil
+	}
+	if host == "" {
+		return inetaddr(net, nil, portnum, zone), nil
+	}
+	// Try as an IP address.
+	if ip := ParseIP(host); ip != nil {
+		return inetaddr(net, ip, portnum, zone), nil
+	}
+	var filter func(IP) IP
+	if net != "" && net[len(net)-1] == '4' {
+		filter = ipv4only
+	}
+	if net != "" && net[len(net)-1] == '6' {
+		filter = ipv6only
+	}
+	// Try as a DNS name.
+	addrs, err := lookupHostDeadline(host, deadline)
 	if err != nil {
-		return nil, 0, err
+		return nil, err
 	}
-
-	return addr, p, nil
+	ip := firstFavoriteAddr(filter, addrs)
+	if ip == nil {
+		// should not happen
+		return nil, &AddrError{"LookupHost returned no suitable address", addrs[0]}
+	}
+	return inetaddr(net, ip, portnum, zone), nil
 }
 
 func zoneToString(zone int) string {

src/pkg/net/tcp_test.go

@@ -5,6 +5,7 @@
 package net
 
 import (
+	"reflect"
 	"runtime"
 	"testing"
 	"time"
@@ -117,6 +118,33 @@ func benchmarkTCP(b *testing.B, persistent, timeout bool) {
 	}
 }
 
+var resolveTCPAddrTests = []struct {
+	net     string
+	litAddr string
+	addr    *TCPAddr
+	err     error
+}{
+	{"tcp", "127.0.0.1:0", &TCPAddr{IP: IPv4(127, 0, 0, 1), Port: 0}, nil},
+	{"tcp4", "127.0.0.1:65535", &TCPAddr{IP: IPv4(127, 0, 0, 1), Port: 65535}, nil},
+
+	{"tcp", "[::1]:1", &TCPAddr{IP: ParseIP("::1"), Port: 1}, nil},
+	{"tcp6", "[::1]:65534", &TCPAddr{IP: ParseIP("::1"), Port: 65534}, nil},
+
+	{"http", "127.0.0.1:0", nil, UnknownNetworkError("http")},
+}
+
+func TestResolveTCPAddr(t *testing.T) {
+	for _, tt := range resolveTCPAddrTests {
+		addr, err := ResolveTCPAddr(tt.net, tt.litAddr)
+		if err != tt.err {
+			t.Fatalf("ResolveTCPAddr(%v, %v) failed: %v", tt.net, tt.litAddr, err)
+		}
+		if !reflect.DeepEqual(addr, tt.addr) {
+			t.Fatalf("got %#v; expected %#v", addr, tt.addr)
+		}
+	}
+}
+
 var tcpListenerNameTests = []struct {
 	net   string
 	laddr *TCPAddr

src/pkg/net/tcpsock.go

@@ -6,8 +6,6 @@
 
 package net
 
-import "time"
-
 // TCPAddr represents the address of a TCP end point.
 type TCPAddr struct {
 	IP   IP
@@ -31,13 +29,14 @@ func (a *TCPAddr) String() string {
 // "tcp4" or "tcp6".  A literal IPv6 host address must be
 // enclosed in square brackets, as in "[::]:80".
 func ResolveTCPAddr(net, addr string) (*TCPAddr, error) {
-	return resolveTCPAddr(net, addr, noDeadline)
-}
-
-func resolveTCPAddr(net, addr string, deadline time.Time) (*TCPAddr, error) {
-	ip, port, err := hostPortToIP(net, addr, deadline)
+	switch net {
+	case "tcp", "tcp4", "tcp6":
+	default:
+		return nil, UnknownNetworkError(net)
+	}
+	a, err := resolveInternetAddr(net, addr, noDeadline)
 	if err != nil {
 		return nil, err
 	}
-	return &TCPAddr{IP: ip, Port: port}, nil
+	return a.(*TCPAddr), nil
 }

src/pkg/net/udp_test.go

@@ -5,10 +5,38 @@
 package net
 
 import (
+	"reflect"
 	"runtime"
 	"testing"
 )
 
+var resolveUDPAddrTests = []struct {
+	net     string
+	litAddr string
+	addr    *UDPAddr
+	err     error
+}{
+	{"udp", "127.0.0.1:0", &UDPAddr{IP: IPv4(127, 0, 0, 1), Port: 0}, nil},
+	{"udp4", "127.0.0.1:65535", &UDPAddr{IP: IPv4(127, 0, 0, 1), Port: 65535}, nil},
+
+	{"udp", "[::1]:1", &UDPAddr{IP: ParseIP("::1"), Port: 1}, nil},
+	{"udp6", "[::1]:65534", &UDPAddr{IP: ParseIP("::1"), Port: 65534}, nil},
+
+	{"sip", "127.0.0.1:0", nil, UnknownNetworkError("sip")},
+}
+
+func TestResolveUDPAddr(t *testing.T) {
+	for _, tt := range resolveUDPAddrTests {
+		addr, err := ResolveUDPAddr(tt.net, tt.litAddr)
+		if err != tt.err {
+			t.Fatalf("ResolveUDPAddr(%v, %v) failed: %v", tt.net, tt.litAddr, err)
+		}
+		if !reflect.DeepEqual(addr, tt.addr) {
+			t.Fatalf("got %#v; expected %#v", addr, tt.addr)
+		}
+	}
+}
+
 func TestWriteToUDP(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":

src/pkg/net/udpsock.go

@@ -6,10 +6,7 @@
 
 package net
 
-import (
-	"errors"
-	"time"
-)
+import "errors"
 
 var ErrWriteToConnected = errors.New("use of WriteTo with pre-connected UDP")
 
@@ -36,13 +33,14 @@ func (a *UDPAddr) String() string {
 // "udp4" or "udp6".  A literal IPv6 host address must be
 // enclosed in square brackets, as in "[::]:80".
 func ResolveUDPAddr(net, addr string) (*UDPAddr, error) {
-	return resolveUDPAddr(net, addr, noDeadline)
-}
-
-func resolveUDPAddr(net, addr string, deadline time.Time) (*UDPAddr, error) {
-	ip, port, err := hostPortToIP(net, addr, deadline)
+	switch net {
+	case "udp", "udp4", "udp6":
+	default:
+		return nil, UnknownNetworkError(net)
+	}
+	a, err := resolveInternetAddr(net, addr, noDeadline)
 	if err != nil {
 		return nil, err
 	}
-	return &UDPAddr{IP: ip, Port: port}, nil
+	return a.(*UDPAddr), nil
 }