netdev - Re: TCP MD5 and socket accept

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Message-ID: <396556a20806260746s351ca696xb44b9b4d6bf257c2@mail.gmail.com>
Date:	Thu, 26 Jun 2008 07:46:59 -0700
From:	"Adam Langley" <agl@...erialviolet.org>
To:	"Stephen Hemminger" <shemminger@...tta.com>
Cc:	"David Miller" <davem@...emloft.net>,
	"吉藤英明" <yoshfuji@...ux-ipv6.org>,
	netdev@...r.kernel.org
Subject: Re: TCP MD5 and socket accept

On Wed, Jun 25, 2008 at 10:56 PM, Stephen Hemminger
<shemminger@...tta.com> wrote:
> What will break if tcp_create_openreq_child was fixed to copy md5_info if
> present?
>
> This all comes about because right now using Quagga a Linux to Linux
> works with TCP MD5. But a Linux to Cisco connection fails if using
> TCP MD5.

I'll have a look at this later today but, as you say, Linux to Linux
works, and getting the key wrong certainly breaks it (and without
setsockopt on the child, I believe). So some MD5 information is
getting copied from listening sockets to children.

Also note the MD5 on Linux is pretty badly broken in the face of
packet loss at the moment. I have patches floating around to fix it,
but not in any trees yet.

AGL

-- 
Adam Langley agl@...erialviolet.org http://www.imperialviolet.org
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