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Re: [PATCH][BZ 14307] Avoid duplicate DNS requests in case answeris longer than a (relatively small) implementation limit


On Mon, 2 Jul 2012 22:38:39 -0600, Jeroen wrote:
> This patch increases the size of the temporary buffer by
> sizeof(struct host_data) - in two places - such that the first query
> response fits more easily. Because sizeof(struct host_data) varies
> per target platform, this patch reduces (but does not totally
> eliminate) the observed difference in network behavior for various
> platforms.

A long term fix would be to avoid the repeated queries in the first
place, but a cursory look at the code suggests that is going to be a
small project in itself, so it would be a good idea to get this fix in
for now.

> * This patch likely also fixes bug #13904

Yes it should.

> * I found the issue in a call to __gethostbyname2_r() in
> getaddrinfo() and tested the attached fix; I subsequently noticed
> that a similar buffer was used in a call to __gethostbyaddr_r() in
> the same function, so I applied a similar fix there - but without
> testing

You will need a fix for gethostbyname4_r as well on similar lines.

> 2012-07-02  Jeroen van Bemmel <jvb127@gmail.com>
                               ^^
Two spaces between name and email address

A new line here, followed by the bugzilla numbers in square brackets
like this:

	[BZ #14307][BZ #13904]
> 	* sysdeps/posix/getaddrinfo.c ( gaih_inet ): Increase the
> size of the temporary buffer used to invoke __gethostbyname2_r and
> __gethostbyaddr_r to make room for struct host_data.
> 	* resolv/nss_dns/dns-host.c (global scope): Move definition
> of implementation constants MAX_NR_ALIASES and MAX_NR_ADDRS to header
> file nss/nsswitch.h.
> 	* nss/nsswitch.h (global scope): Add definition of
> implementation constants MAX_NR_ALIASES and MAX_NR_ADDRS (moved from
> resolv/nss_dns/dns-host.c).

All of this should be wrapped at 72 characters and correctly tabbed.

Please resubmit the patch and changelog entry with the changes above.
Also, I don't know if this counts as a trivial enough change to not
require a copyright assignment to FSF, so I'll let someone else who
knows better, comment on that.


Thanks,
Siddhesh


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