/* ** Zabbix ** Copyright (C) 2001-2025 Zabbix SIA ** ** This program is free software; you can redistribute it and/or modify ** it under the terms of the GNU General Public License as published by ** the Free Software Foundation; either version 2 of the License, or ** (at your option) any later version. ** ** This program is distributed in the hope that it will be useful, ** but WITHOUT ANY WARRANTY; without even the implied warranty of ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ** GNU General Public License for more details. ** ** You should have received a copy of the GNU General Public License ** along with this program; if not, write to the Free Software ** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. **/ package zbxcomms import ( "context" "fmt" "net" "syscall" "zabbix.com/pkg/tls" ) func Listen(address string, args ...interface{}) (c *Listener, err error) { var tlsconfig *tls.Config if len(args) > 0 { var ok bool if tlsconfig, ok = args[0].(*tls.Config); !ok { return nil, fmt.Errorf("invalid TLS configuration parameter of type %T", args[0]) } } // prevent other processes from binding to the same port // SO_EXCLUSIVEADDRUSE is mutually exclusive with SO_REUSEADDR // on Windows SO_REUSEADDR has different semantics than on Unix // https://msdn.microsoft.com/en-us/library/windows/desktop/ms740621(v=vs.85).aspx lc := net.ListenConfig{ Control: func(network, address string, conn syscall.RawConn) error { var operr error if err := conn.Control(func(fd uintptr) { operr = syscall.SetsockoptInt(syscall.Handle(fd), syscall.SOL_SOCKET, ^syscall.SO_REUSEADDR, 1) }); err != nil { return err } return operr }, } l, tmperr := lc.Listen(context.Background(), "tcp", address) if tmperr != nil { return nil, fmt.Errorf("Listen failed: %s", tmperr.Error()) } c = &Listener{listener: l.(*net.TCPListener), tlsconfig: tlsconfig} return }