This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: [PATCH] resolv: Enable full ICMP errors for UDP DNS sockets [BZ #24047]
- From: Zack Weinberg <zackw at panix dot com>
- To: Florian Weimer <fweimer at redhat dot com>
- Cc: GNU C Library <libc-alpha at sourceware dot org>
- Date: Thu, 7 Mar 2019 07:09:15 -0500
- Subject: Re: [PATCH] resolv: Enable full ICMP errors for UDP DNS sockets [BZ #24047]
- References: <87mumi6075.fsf@oldenburg2.str.redhat.com> <87lg1r7wwb.fsf@oldenburg2.str.redhat.com> <CAKCAbMgAHEYrCs-Np-9yFosG7bVqrM_WLa=mKsat8NamaRAZQw@mail.gmail.com>
On Thu, Mar 7, 2019 at 7:08 AM Zack Weinberg <zackw@panix.com> wrote:
>
> On Thu, Mar 7, 2019 at 6:21 AM Florian Weimer <fweimer@redhat.com> wrote:
> >
> > * Florian Weimer:
> >
> > > The Linux kernel suppresses some ICMP error messages by default for
> > > UDP sockets. This commit enables full ICMP error reporting,
> > > hopefully resulting in faster failover to working name servers.
> ...
>
> The documentation makes it sound like IP_RECVERR doesn't do anything
> by itself, you need to call recvmsg(MSG_ERRQUEUE) to actually see the
> errors. As far as I can tell, res_send.c doesn't do that, either
> before or after this patch. Is the documentation wrong?
er, by "the documentation" I am referring to the ip(7) manpage.
zw