global: use netip where possible now

There are more places where we'll need to add it later, when Go 1.18
comes out with support for it in the "net" package. Also, allowedips
still uses slices internally, which might be suboptimal.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

5 files changed, 50 insertions, 89 deletions

diff --git a/conn/bind_linux.go b/conn/bind_linux.go
index 7b970e6..da0670a 100644
--- a/conn/bind_linux.go
+++ b/conn/bind_linux.go
@@ -14,6 +14,7 @@ import (
 	"unsafe"
 
 	"golang.org/x/sys/unix"
+	"golang.zx2c4.com/go118/netip"
 )
 
 type ipv4Source struct {
@@ -70,32 +71,30 @@ var _ Bind = (*LinuxSocketBind)(nil)
 
 func (*LinuxSocketBind) ParseEndpoint(s string) (Endpoint, error) {
 	var end LinuxSocketEndpoint
-	addr, err := parseEndpoint(s)
+	e, err := netip.ParseAddrPort(s)
 	if err != nil {
 		return nil, err
 	}
 
-	ipv4 := addr.IP.To4()
-	if ipv4 != nil {
+	if e.Addr().Is4() {
 		dst := end.dst4()
 		end.isV6 = false
-		dst.Port = addr.Port
-		copy(dst.Addr[:], ipv4)
+		dst.Port = int(e.Port())
+		dst.Addr = e.Addr().As4()
 		end.ClearSrc()
 		return &end, nil
 	}
 
-	ipv6 := addr.IP.To16()
-	if ipv6 != nil {
-		zone, err := zoneToUint32(addr.Zone)
+	if e.Addr().Is6() {
+		zone, err := zoneToUint32(e.Addr().Zone())
 		if err != nil {
 			return nil, err
 		}
 		dst := end.dst6()
 		end.isV6 = true
-		dst.Port = addr.Port
+		dst.Port = int(e.Port())
 		dst.ZoneId = zone
-		copy(dst.Addr[:], ipv6[:])
+		dst.Addr = e.Addr().As16()
 		end.ClearSrc()
 		return &end, nil
 	}
@@ -266,29 +265,19 @@ func (bind *LinuxSocketBind) Send(buff []byte, end Endpoint) error {
 	}
 }
 
-func (end *LinuxSocketEndpoint) SrcIP() net.IP {
+func (end *LinuxSocketEndpoint) SrcIP() netip.Addr {
 	if !end.isV6 {
-		return net.IPv4(
-			end.src4().Src[0],
-			end.src4().Src[1],
-			end.src4().Src[2],
-			end.src4().Src[3],
-		)
+		return netip.AddrFrom4(end.src4().Src)
 	} else {
-		return end.src6().src[:]
+		return netip.AddrFrom16(end.src6().src)
 	}
 }
 
-func (end *LinuxSocketEndpoint) DstIP() net.IP {
+func (end *LinuxSocketEndpoint) DstIP() netip.Addr {
 	if !end.isV6 {
-		return net.IPv4(
-			end.dst4().Addr[0],
-			end.dst4().Addr[1],
-			end.dst4().Addr[2],
-			end.dst4().Addr[3],
-		)
+		return netip.AddrFrom4(end.dst4().Addr)
 	} else {
-		return end.dst6().Addr[:]
+		return netip.AddrFrom16(end.dst6().Addr)
 	}
 }
 
@@ -305,14 +294,13 @@ func (end *LinuxSocketEndpoint) SrcToString() string {
 }
 
 func (end *LinuxSocketEndpoint) DstToString() string {
-	var udpAddr net.UDPAddr
-	udpAddr.IP = end.DstIP()
+	var port int
 	if !end.isV6 {
-		udpAddr.Port = end.dst4().Port
+		port = end.dst4().Port
 	} else {
-		udpAddr.Port = end.dst6().Port
+		port = end.dst6().Port
 	}
-	return udpAddr.String()
+	return netip.AddrPortFrom(end.DstIP(), uint16(port)).String()
 }
 
 func (end *LinuxSocketEndpoint) ClearDst() {
diff --git a/conn/bind_std.go b/conn/bind_std.go
index cb85cfd..a3cbb15 100644
--- a/conn/bind_std.go
+++ b/conn/bind_std.go
@@ -10,6 +10,8 @@ import (
 	"net"
 	"sync"
 	"syscall"
+
+	"golang.zx2c4.com/go118/netip"
 )
 
 // StdNetBind is meant to be a temporary solution on platforms for which
@@ -32,18 +34,23 @@ var _ Bind = (*StdNetBind)(nil)
 var _ Endpoint = (*StdNetEndpoint)(nil)
 
 func (*StdNetBind) ParseEndpoint(s string) (Endpoint, error) {
-	addr, err := parseEndpoint(s)
-	return (*StdNetEndpoint)(addr), err
+	e, err := netip.ParseAddrPort(s)
+	return (*StdNetEndpoint)(&net.UDPAddr{
+		IP:   e.Addr().AsSlice(),
+		Port: int(e.Port()),
+		Zone: e.Addr().Zone(),
+	}), err
 }
 
 func (*StdNetEndpoint) ClearSrc() {}
 
-func (e *StdNetEndpoint) DstIP() net.IP {
-	return (*net.UDPAddr)(e).IP
+func (e *StdNetEndpoint) DstIP() netip.Addr {
+	a, _ := netip.AddrFromSlice((*net.UDPAddr)(e).IP)
+	return a
 }
 
-func (e *StdNetEndpoint) SrcIP() net.IP {
-	return nil // not supported
+func (e *StdNetEndpoint) SrcIP() netip.Addr {
+	return netip.Addr{} // not supported
 }
 
 func (e *StdNetEndpoint) DstToBytes() []byte {
diff --git a/conn/bind_windows.go b/conn/bind_windows.go
index 42e06ad..26a3af8 100644
--- a/conn/bind_windows.go
+++ b/conn/bind_windows.go
@@ -15,6 +15,7 @@ import (
 	"unsafe"
 
 	"golang.org/x/sys/windows"
+	"golang.zx2c4.com/go118/netip"
 
 	"golang.zx2c4.com/wireguard/conn/winrio"
 )
@@ -128,18 +129,18 @@ func (*WinRingBind) ParseEndpoint(s string) (Endpoint, error) {
 
 func (*WinRingEndpoint) ClearSrc() {}
 
-func (e *WinRingEndpoint) DstIP() net.IP {
+func (e *WinRingEndpoint) DstIP() netip.Addr {
 	switch e.family {
 	case windows.AF_INET:
-		return append([]byte{}, e.data[2:6]...)
+		return netip.AddrFrom4(*(*[4]byte)(e.data[2:6]))
 	case windows.AF_INET6:
-		return append([]byte{}, e.data[6:22]...)
+		return netip.AddrFrom16(*(*[16]byte)(e.data[6:22]))
 	}
-	return nil
+	return netip.Addr{}
 }
 
-func (e *WinRingEndpoint) SrcIP() net.IP {
-	return nil // not supported
+func (e *WinRingEndpoint) SrcIP() netip.Addr {
+	return netip.Addr{} // not supported
 }
 
 func (e *WinRingEndpoint) DstToBytes() []byte {
@@ -161,15 +162,13 @@ func (e *WinRingEndpoint) DstToBytes() []byte {
 func (e *WinRingEndpoint) DstToString() string {
 	switch e.family {
 	case windows.AF_INET:
-		addr := net.UDPAddr{IP: e.data[2:6], Port: int(binary.BigEndian.Uint16(e.data[0:2]))}
-		return addr.String()
+		netip.AddrPortFrom(netip.AddrFrom4(*(*[4]byte)(e.data[2:6])), binary.BigEndian.Uint16(e.data[0:2])).String()
 	case windows.AF_INET6:
 		var zone string
 		if scope := *(*uint32)(unsafe.Pointer(&e.data[22])); scope > 0 {
 			zone = strconv.FormatUint(uint64(scope), 10)
 		}
-		addr := net.UDPAddr{IP: e.data[6:22], Zone: zone, Port: int(binary.BigEndian.Uint16(e.data[0:2]))}
-		return addr.String()
+		return netip.AddrPortFrom(netip.AddrFrom16(*(*[16]byte)(e.data[6:22])).WithZone(zone), binary.BigEndian.Uint16(e.data[0:2])).String()
 	}
 	return ""
 }
diff --git a/conn/bindtest/bindtest.go b/conn/bindtest/bindtest.go
index 7d43fb3..6a45896 100644
--- a/conn/bindtest/bindtest.go
+++ b/conn/bindtest/bindtest.go
@@ -10,8 +10,8 @@ import (
 	"math/rand"
 	"net"
 	"os"
-	"strconv"
 
+	"golang.zx2c4.com/go118/netip"
 	"golang.zx2c4.com/wireguard/conn"
 )
 
@@ -61,9 +61,9 @@ func (c ChannelEndpoint) DstToString() string { return fmt.Sprintf("127.0.0.1:%d
 
 func (c ChannelEndpoint) DstToBytes() []byte { return []byte{byte(c)} }
 
-func (c ChannelEndpoint) DstIP() net.IP { return net.IPv4(127, 0, 0, 1) }
+func (c ChannelEndpoint) DstIP() netip.Addr { return netip.AddrFrom4([4]byte{127, 0, 0, 1}) }
 
-func (c ChannelEndpoint) SrcIP() net.IP { return nil }
+func (c ChannelEndpoint) SrcIP() netip.Addr { return netip.Addr{} }
 
 func (c *ChannelBind) Open(port uint16) (fns []conn.ReceiveFunc, actualPort uint16, err error) {
 	c.closeSignal = make(chan bool)
@@ -119,13 +119,9 @@ func (c *ChannelBind) Send(b []byte, ep conn.Endpoint) error {
 }
 
 func (c *ChannelBind) ParseEndpoint(s string) (conn.Endpoint, error) {
-	_, port, err := net.SplitHostPort(s)
+	addr, err := netip.ParseAddrPort(s)
 	if err != nil {
 		return nil, err
 	}
-	i, err := strconv.ParseUint(port, 10, 16)
-	if err != nil {
-		return nil, err
-	}
-	return ChannelEndpoint(i), nil
+	return ChannelEndpoint(addr.Port()), nil
 }
diff --git a/conn/conn.go b/conn/conn.go
index 9cce9ad..35fb6b1 100644
--- a/conn/conn.go
+++ b/conn/conn.go
@@ -9,10 +9,11 @@ package conn
 import (
 	"errors"
 	"fmt"
-	"net"
 	"reflect"
 	"runtime"
 	"strings"
+
+	"golang.zx2c4.com/go118/netip"
 )
 
 // A ReceiveFunc receives a single inbound packet from the network.
@@ -68,8 +69,8 @@ type Endpoint interface {
 	SrcToString() string // returns the local source address (ip:port)
 	DstToString() string // returns the destination address (ip:port)
 	DstToBytes() []byte  // used for mac2 cookie calculations
-	DstIP() net.IP
-	SrcIP() net.IP
+	DstIP() netip.Addr
+	SrcIP() netip.Addr
 }
 
 var (
@@ -119,33 +120,3 @@ func (fn ReceiveFunc) PrettyName() string {
 	}
 	return name
 }
-
-func parseEndpoint(s string) (*net.UDPAddr, error) {
-	// ensure that the host is an IP address
-
-	host, _, err := net.SplitHostPort(s)
-	if err != nil {
-		return nil, err
-	}
-	if i := strings.LastIndexByte(host, '%'); i > 0 && strings.IndexByte(host, ':') >= 0 {
-		// Remove the scope, if any. ResolveUDPAddr below will use it, but here we're just
-		// trying to make sure with a small sanity test that this is a real IP address and
-		// not something that's likely to incur DNS lookups.
-		host = host[:i]
-	}
-	if ip := net.ParseIP(host); ip == nil {
-		return nil, errors.New("Failed to parse IP address: " + host)
-	}
-
-	// parse address and port
-
-	addr, err := net.ResolveUDPAddr("udp", s)
-	if err != nil {
-		return nil, err
-	}
-	ip4 := addr.IP.To4()
-	if ip4 != nil {
-		addr.IP = ip4
-	}
-	return addr, err
-}