From: Jamie Lokier <lk@tantalophile.demon.co.uk>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip alias bug 2.4.9 and 2.2.19]
Date: Fri, 7 Sep 2001 02:47:46 +0100 [thread overview]
Message-ID: <20010907024746.C7329@kushida.degree2.com> (raw)
In-Reply-To: <20010906212303.A23595@castle.nmd.msu.ru> <20010906173948.502BFBC06C@spike.porcupine.org> <9n8ev1$qba$1@cesium.transmeta.com>
In-Reply-To: <9n8ev1$qba$1@cesium.transmeta.com>; from hpa@zytor.com on Thu, Sep 06, 2001 at 11:23:29AM -0700
H. Peter Anvin wrote:
> In autofs, I use the following technique to determine if the IP number
> for a host is local (and therefore vfsbinds can be used rather than
> NFS mounts):
>
> connect a datagram socket (which won't produce any actual traffic) to
> the remote host with INADDR_ANY as the local address, and then query
> the local address. If the local address is the same as the remote
> address, the address is local.
Nice. Gives false negatives in some cases (e.g. a local tunnel) but
that doesn't really matter.
I've considered this technique for deciding whether it's safe to use the
MIT-SHM extension with X:
Open a SHM segment; write fairly secure random data into it; ask the X
server to connect to that segment and read it back as an image over the
X protocol; check whether they match.
If the X server reports an error, it's remote. If it finds a SHM
segment it may still be remote, hence the random data check.
-- Jamie
next prev parent reply other threads:[~2001-09-07 13:23 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20010905170037.A6473@emma1.emma.line.org.suse.lists.linux.kernel>
[not found] ` <20010905152738.C5912BC06D@spike.porcupine.org.suse.lists.linux.kernel>
[not found] ` <20010905182033.D3926@emma1.emma.line.org.suse.lists.linux.kernel>
2001-09-05 19:26 ` ioctl SIOCGIFNETMASK: ip alias bug 2.4.9 and 2.2.19 Andi Kleen
2001-09-06 13:11 ` Matthias Andree
2001-09-06 13:35 ` Andrey Savochkin
2001-09-06 14:04 ` Wietse Venema
2001-09-06 14:21 ` Matthias Andree
2001-09-06 15:37 ` notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip alias bug 2.4.9 and 2.2.19] Andrey Savochkin
2001-09-06 15:58 ` Wietse Venema
2001-09-06 16:39 ` notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip alias Alan Cox
2001-09-06 16:45 ` Wietse Venema
2001-09-06 16:44 ` notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip alias bug 2.4.9 and 2.2.19] Andrey Savochkin
2001-09-06 16:47 ` Andi Kleen
2001-09-06 17:04 ` Andrey Savochkin
2001-09-06 16:50 ` Wietse Venema
2001-09-06 17:01 ` notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip alias Alan Cox
2001-09-06 17:23 ` Wietse Venema
2001-09-06 17:45 ` Charles Cazabon
2001-09-06 18:11 ` Steve VanDevender
2001-09-06 18:25 ` Wietse Venema
2001-09-06 19:10 ` Steve VanDevender
2001-09-06 19:47 ` Alan Cox
2001-09-06 20:16 ` Wietse Venema
2001-09-06 19:34 ` Alan Cox
2001-09-06 19:41 ` Wietse Venema
2001-09-06 20:18 ` Alan Cox
2001-09-06 20:11 ` Matthias Andree
2001-09-06 20:23 ` Alan Cox
2001-09-06 20:31 ` Andi Kleen
2001-09-06 20:52 ` Matthias Andree
2001-09-07 9:06 ` Henning P. Schmiedehausen
2001-09-07 8:52 ` Matthew Kirkwood
2001-09-08 16:31 ` Wietse Venema
2001-09-13 14:35 ` Pavel Machek
2001-09-06 17:03 ` notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip alias bug 2.4.9 and 2.2.19] Andi Kleen
2001-09-06 17:23 ` Andrey Savochkin
2001-09-06 17:39 ` Wietse Venema
2001-09-06 18:23 ` H. Peter Anvin
2001-09-07 1:47 ` Jamie Lokier [this message]
2001-09-07 5:48 ` notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip aliasbug " Ben Greear
2001-09-07 5:50 ` H. Peter Anvin
2001-09-17 21:39 ` Ben Greear
2001-09-07 6:26 ` Andrey Savochkin
2001-09-07 6:21 ` H. Peter Anvin
2001-09-06 19:15 ` notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip alias bug " dean gaudet
2001-09-06 19:33 ` Wietse Venema
2001-09-06 20:51 ` Matti Aarnio
2001-09-07 7:29 ` Andrey Savochkin
2001-09-07 7:35 ` Matthias Andree
2001-09-08 13:16 ` notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip alias Kai Henningsen
2001-09-07 10:30 ` notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip alias bug 2.4.9 and 2.2.19] Mike Jagdis
2001-09-07 11:04 ` Matthias Andree
2001-09-07 15:34 ` Kurt Roeckx
2001-09-06 18:20 ` H. Peter Anvin
2001-09-06 16:01 ` Matthias Andree
2001-09-06 16:38 ` Andrey Savochkin
2001-09-06 16:43 ` Wietse Venema
2001-09-06 17:03 ` Charles Cazabon
2001-09-06 17:05 ` Alex Bligh - linux-kernel
2001-09-06 17:37 ` Andrey Savochkin
2001-09-06 17:55 ` kuznet
2001-09-06 14:51 ` ioctl SIOCGIFNETMASK: ip alias bug 2.4.9 and 2.2.19 Alan Cox
2001-09-06 14:17 ` Matthias Andree
2001-09-08 12:42 ` Kai Henningsen
2001-09-09 0:37 ` Matthias Andree
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