[LTP] TST_GET_UNUSED_PORT returns ports < 1024

[Petr Vorel <pvorel@suse.cz>]

Hi Christian,

> Hi,

> when using the TST_GET_UNUSED_PORT macro you sometimes get ports lower
> than 1024 which would require a testcase to have the
> CAP_NET_BIND_SERVICE capability (or simply run as root).
That surprised me. I thought using bind() with non-root user doesn't do that,
but need to check the implementation in the kernel.

> Of course you could write a wrapper like the following to avoid that
> issue, but in my opinion it would be nice to have the option to get
> non-root ports directly from the library.

> /* Wrapper to to get a non-root port if necessary */
> static int get_port(uid_t uid)
> {
>         static int count = 10;
>         int port;

>         port = TST_GET_UNUSED_PORT(AF_INET, SOCK_STREAM);
>         if (port < 1000 && uid != 0) {
>                 if (!count)
>                         tst_brk(TBROK, "Could not get fitting port");
>                 count--;
>                 return get_port(uid);
>         }
>         return port;
> }

> Kind regards,

> Christian


Kind regards,
Petr