vendor: Update everything

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4620

vendor/golang.org/x/net/ipv4/payload_cmsg.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !plan9,!windows
+// +build !nacl,!plan9,!windows
 
 package ipv4
 
@@ -19,37 +19,7 @@ func (c *payloadHandler) ReadFrom(b []byte) (n int, cm *ControlMessage, src net.
 	if !c.ok() {
 		return 0, nil, nil, syscall.EINVAL
 	}
-	oob := newControlMessage(&c.rawOpt)
-	var oobn int
-	switch c := c.PacketConn.(type) {
-	case *net.UDPConn:
-		if n, oobn, _, src, err = c.ReadMsgUDP(b, oob); err != nil {
-			return 0, nil, nil, err
-		}
-	case *net.IPConn:
-		if sockOpts[ssoStripHeader].name > 0 {
-			if n, oobn, _, src, err = c.ReadMsgIP(b, oob); err != nil {
-				return 0, nil, nil, err
-			}
-		} else {
-			nb := make([]byte, maxHeaderLen+len(b))
-			if n, oobn, _, src, err = c.ReadMsgIP(nb, oob); err != nil {
-				return 0, nil, nil, err
-			}
-			hdrlen := int(nb[0]&0x0f) << 2
-			copy(b, nb[hdrlen:])
-			n -= hdrlen
-		}
-	default:
-		return 0, nil, nil, errInvalidConnType
-	}
-	if cm, err = parseControlMessage(oob[:oobn]); err != nil {
-		return 0, nil, nil, err
-	}
-	if cm != nil {
-		cm.Src = netAddrToIP4(src)
-	}
-	return
+	return c.readFrom(b)
 }
 
 // WriteTo writes a payload of the IPv4 datagram, to the destination
@@ -62,20 +32,5 @@ func (c *payloadHandler) WriteTo(b []byte, cm *ControlMessage, dst net.Addr) (n
 	if !c.ok() {
 		return 0, syscall.EINVAL
 	}
-	oob := marshalControlMessage(cm)
-	if dst == nil {
-		return 0, errMissingAddress
-	}
-	switch c := c.PacketConn.(type) {
-	case *net.UDPConn:
-		n, _, err = c.WriteMsgUDP(b, oob, dst.(*net.UDPAddr))
-	case *net.IPConn:
-		n, _, err = c.WriteMsgIP(b, oob, dst.(*net.IPAddr))
-	default:
-		return 0, errInvalidConnType
-	}
-	if err != nil {
-		return 0, err
-	}
-	return
+	return c.writeTo(b, cm, dst)
 }