From: David Howells <dhowells@redhat•com>
To: linux-nfs@vger•kernel.org, linux-cifs@vger•kernel.org,
linux-afs@lists•infradead.org, ceph-devel@vger•kernel.org
Cc: dhowells@redhat•com, keyrings@vger•kernel.org,
netdev@vger•kernel.org, linux-kernel@vger•kernel.org,
fweimer@redhat•com
Subject: What's a good default TTL for DNS keys in the kernel
Date: Tue, 14 Apr 2020 15:20:10 +0100 [thread overview]
Message-ID: <3865908.1586874010@warthog.procyon.org.uk> (raw)
Since key.dns_resolver isn't given a TTL for the address information obtained
for getaddrinfo(), no expiry is set on dns_resolver keys in the kernel for
NFS, CIFS or Ceph. AFS gets one if it looks up a cell SRV or AFSDB record
because that is looked up in the DNS directly, but it doesn't look up A or
AAAA records, so doesn't get an expiry for the addresses themselves.
I've previously asked the libc folks if there's a way to get this information
exposed in struct addrinfo, but I don't think that ended up going anywhere -
and, in any case, would take a few years to work through the system.
For the moment, I think I should put a default on any dns_resolver keys and
have it applied either by the kernel (configurable with a /proc/sys/ setting)
or by the key.dnf_resolver program (configurable with an /etc file).
Any suggestion as to the preferred default TTL? 10 minutes?
David
next reply other threads:[~2020-04-14 14:20 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-14 14:20 David Howells [this message]
2020-04-14 20:16 ` What's a good default TTL for DNS keys in the kernel Jeff Layton
2020-04-15 17:07 ` Steve French
2020-04-16 10:15 ` David Howells
2020-04-15 9:44 ` Florian Weimer
2020-04-16 10:27 ` David Howells
2020-04-16 10:33 ` Florian Weimer
2020-04-16 13:01 ` David Howells
2020-04-16 13:40 ` Chuck Lever
2020-04-17 11:31 ` Aurélien Aptel
2020-04-17 23:23 ` Steve French
2020-04-18 18:10 ` Florian Weimer
2020-04-19 4:53 ` Steve French
2020-04-19 8:37 ` David Howells
2020-04-20 0:58 ` Paulo Alcantara
2020-04-20 13:13 ` David Howells
2020-04-20 18:21 ` Paulo Alcantara
2020-04-20 22:14 ` cifs - Race between IP address change and sget()? David Howells
2020-04-20 22:30 ` Jeff Layton
2020-04-21 1:29 ` Ronnie Sahlberg
2020-04-21 2:26 ` Steve French
2020-04-21 2:29 ` Steve French
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