netdev - Re: [TCP]: min_t/max_t confusion in tcp_select_initial

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20091223.131526.193724825.davem@davemloft.net>
Date:	Wed, 23 Dec 2009 13:15:26 -0800 (PST)
From:	David Miller <davem@...emloft.net>
To:	ilpo.jarvinen@...sinki.fi
Cc:	roel.kluin@...il.com, netdev@...r.kernel.org
Subject: Re: [TCP]: min_t/max_t confusion in tcp_select_initial_window()?

From: "Ilpo Järvinen" <ilpo.jarvinen@...sinki.fi>
Date: Wed, 23 Dec 2009 21:45:57 +0200 (EET)

> On Tue, 22 Dec 2009, David Miller wrote:
> 
>> From: Roel Kluin <roel.kluin@...il.com>
>> Date: Wed, 23 Dec 2009 03:00:24 +0100
>> 
>> > I could be confused, but in net/ipv4/tcp_output.c:217:
>> > 
>> >                 space = max_t(u32, sysctl_tcp_rmem[2], sysctl_rmem_max);
>> >                 space = min_t(u32, space, *window_clamp);
>> > ------------------------^^^^^
 ...
> 
> I don't understand how window_clamp line could be changed to max_t.
> ...I guess min in both would seem the most reasonable one?

Nope, the first one must be max.  Since I'm pretty sure we let the
dynamic RX buffer resizing exceed sysctl_rmem_max if necessary.

And that's what is controlled by sysctl_tcp_rmem[2]
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html