package dialer import ( "net" "net/netip" "syscall" "golang.org/x/sys/unix" ) type controlFn = func(network, address string, c syscall.RawConn) error func bindControl(ifaceName string, chain controlFn) controlFn { return func(network, address string, c syscall.RawConn) (err error) { defer func() { if err == nil && chain != nil { err = chain(network, address, c) } }() addrPort, err := netip.ParseAddrPort(address) if err == nil && !addrPort.Addr().IsGlobalUnicast() { return } var innerErr error err = c.Control(func(fd uintptr) { innerErr = unix.BindToDevice(int(fd), ifaceName) }) if innerErr != nil { err = innerErr } return } } func bindIfaceToDialer(ifaceName string, dialer *net.Dialer, _ string, _ netip.Addr) error { dialer.Control = bindControl(ifaceName, dialer.Control) return nil } func bindIfaceToListenConfig(ifaceName string, lc *net.ListenConfig, _, address string) (string, error) { lc.Control = bindControl(ifaceName, lc.Control) return address, nil }