Re: [PATCH] resolv: Enable full ICMP errors for UDP DNS sockets [BZ #24047]

[Carlos O'Donell <carlos at redhat dot com>]

On 3/12/19 2:04 PM, Florian Weimer wrote:
> * Joseph Myers:
> 
>> This has broken the build for Hurd:
>>
>> res_enable_icmp.c: In function '__res_enable_icmp':
>> res_enable_icmp.c:30:38: error: 'IP_RECVERR' undeclared (first use in this function); did you mean 'IPV6_RECVERR'?
>>
>> No idea why the generic bits/in.h as used for Hurd defines IPV6_RECVERR 
>> but not IP_RECVERR, or what Hurd actually implements in this regard.
> 
> Sorry about that.
> 
> Thanks for pointing out the IPV6_RECVERR definition, I would have missed
> that.
> 
> XNU does not support IP_RECVERR either, so I think the safest way to
> deal with this is the attached patch.

Agreed.

Integrating the Linux defines and moving them down into the generic
header would be quite a bit of work and validation, probably for not
much gain at this point i.e. defines from sysdeps/unix/sysv/linux/bits/in.h
need to move to bits/in.h to provide IPv4/IPv6 support in one header
(as Joseph points out I also don't know what it was this way today).

> Alternatively, I could add the stub to the generic code, but I think
> doing it this way is clearer for those who read just the resolv code.

Yes, that would be messier than the hurd implementation you're proposing
now.

> hurd: Add no-op version of __res_enable_icmp [BZ #24047]
> 
> Mach does not support IP_RECVERR, so replace this function with a
> stub in a sysdeps override for Hurd.
> 
> This fixes commit 08504de71813ddbd447bfbca4a325cbe8ce8bcda
> ("resolv: Enable full ICMP errors for UDP DNS sockets [BZ #24047]").
> 
> 2019-03-12  Florian Weimer  <fweimer@redhat.com>
> 
> 	[BZ #24047]
> 	* sysdeps/mach/hurd/res_enable_icmp.c: New file.

OK for master.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
 
> diff --git a/sysdeps/mach/hurd/res_enable_icmp.c b/sysdeps/mach/hurd/res_enable_icmp.c
> new file mode 100644
> index 0000000000..4b0456340c
> --- /dev/null
> +++ b/sysdeps/mach/hurd/res_enable_icmp.c
> @@ -0,0 +1,27 @@
> +/* Enable full ICMP errors on a socket.  No-op version for Hurd.
> +   Copyright (C) 2019 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library 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
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +/* Mach does not support the IP_RECVERR extension.  */
> +
> +#include <resolv.h>
> +
> +int
> +__res_enable_icmp (int family, int fd)
> +{
> +  return 0;

OK.

> +}
> 


-- 
Cheers,
Carlos.