move implementation to internal/ directory (#828)

internal/util/tcpsock/tcpsock_freebind_freebsd.go

@@ -0,0 +1,26 @@
+//go:build freebsd
+// +build freebsd
+
+package tcpsock
+
+import (
+	"fmt"
+	"syscall"
+)
+
+func freeBind(network, address string, c syscall.RawConn) error {
+	var err, sockerr error
+	err = c.Control(func(fd uintptr) {
+		if network == "tcp6" {
+			sockerr = syscall.SetsockoptInt(int(fd), syscall.IPPROTO_IPV6, syscall.IPV6_BINDANY, 1)
+		} else if network == "tcp4" {
+			sockerr = syscall.SetsockoptInt(int(fd), syscall.IPPROTO_IP, syscall.IP_BINDANY, 1)
+		} else {
+			sockerr = fmt.Errorf("expecting 'tcp6' or 'tcp4', got %q", network)
+		}
+	})
+	if err != nil {
+		return err
+	}
+	return sockerr
+}