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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 07:08:46 -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>
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?
zw