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From: Casey Leedom <leedom@chelsio•com>
To: David Miller <davem@davemloft•net>
Cc: shemminger@vyatta•com, andy@greyhouse•net, harald@redhat•com,
	bhutchings@solarflare•com, sassmann@redhat•com,
	netdev@vger•kernel.org, linux-kernel@vger•kernel.org,
	gospo@redhat•com, gregory.v.rose@intel•com,
	alexander.h.duyck@intel•com
Subject: Re: [PATCH net-next] sysfs: add entry to indicate network interfaces with random MAC address
Date: Wed, 21 Jul 2010 11:29:47 -0700	[thread overview]
Message-ID: <201007211129.48288.leedom@chelsio.com> (raw)
In-Reply-To: <20100721.103249.107094774.davem@davemloft.net>

| From: David Miller <davem@davemloft•net>
| Date: Wednesday, July 21, 2010 10:32 am
| 
| From: Stephen Hemminger <shemminger@vyatta•com>
| Date: Wed, 21 Jul 2010 10:28:16 -0700
| 
| > IMHO no local assigned address should be used by udev. The cxgb4 driver
| > should be using random value.
| > 
| > Does anyone have an example of locally assigned address that has
| > persistence so that udev could use it.
| 
| The cxgb4 vf addresses are not random because they are fetched from the
| card's NVRAM/EEPROM/firmware/whatever and thus are persistent.
| 
| We definitely want udev to use persistent rules for them.
|
| This whole issue only exists because of the Intel VF case, where it
| lacks persistent addresses but somehow we want to assign persistent
| names to it's VF interfaces.

  Yes, we _explicitly_ wanted to have persistent MAC Addresses for our PCI-E SR-
IOV Virtual Functions for a whole raft of reasons.  The two most important were:

 1. Linux' model for persistent device naming today seems to be
    oriented around persistent network device addresses.

 2. Lots of data centers use MAC addresses for things like DHCP/BOOTP,
    security/filtering, etc.

Our design goal was to look as much like a normal Ethernet MAC as possible in 
order to reduce the need for software/behavior changes.

| One idea I've proposed in other discussions about this is that if the
| address is not persistent (either via the MAC address bit or the sysfs
| value we're thinking of providing here) we use the device's geographic
| location ("device path") as the key for udev stuff.

  Another option might be to have a new Net Device Operations call to ask the 
adapter for a Unique Key.  This could be formed for most devices via a tuple of 
the {PCI Vendor ID, PCI Device ID, Adapter Serial Number, Port Number, [and if 
applicable] Adapter Function ID}.  Of course this could be a fairly long string 
... :-)

Casey

  reply	other threads:[~2010-07-21 18:29 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-20 10:50 [PATCH net-next] sysfs: add entry to indicate network interfaces with random MAC address Stefan Assmann
2010-07-20 11:20 ` Ben Hutchings
2010-07-20 11:47   ` Stefan Assmann
2010-07-20 11:58     ` Alex Badea
2010-07-20 12:17       ` Stefan Assmann
2010-07-20 20:18         ` David Miller
2010-07-21  8:10           ` Stefan Assmann
2010-07-21 13:54             ` Ben Hutchings
2010-07-22 12:50               ` [PATCH net-next] sysfs: add attribute to indicate hw address assignment type Stefan Assmann
2010-07-22 14:07                 ` Ben Hutchings
2010-07-22 14:47                   ` Stefan Assmann
2010-07-25  3:50                     ` David Miller
2010-07-20 12:07     ` [PATCH net-next] sysfs: add entry to indicate network interfaces with random MAC address Ben Hutchings
2010-07-20 12:41       ` Stefan Assmann
2010-07-20 14:29         ` Ben Hutchings
2010-07-20 20:17           ` David Miller
2010-07-20 21:18             ` Stephen Hemminger
2010-07-20 21:20               ` David Miller
2010-07-21  6:26                 ` Harald Hoyer
2010-07-21  6:34                   ` David Miller
2010-07-21  6:47                     ` Harald Hoyer
2010-07-21 15:07                       ` Andy Gospodarek
2010-07-21 16:34                         ` Casey Leedom
2010-07-21 17:28                           ` Stephen Hemminger
2010-07-21 17:32                             ` David Miller
2010-07-21 18:29                               ` Casey Leedom [this message]
2010-07-21 18:39                                 ` David Miller
2010-07-21 19:25                                   ` Casey Leedom
2010-07-21 18:43                                 ` Rose, Gregory V
2010-07-21 18:48                                   ` David Miller
2010-07-21 18:50                                     ` David Miller
2010-07-21 19:02                                       ` Rose, Gregory V
2010-07-21 19:33                                         ` David Miller
2010-07-21 19:35                                           ` Rose, Gregory V
2010-07-22  7:12                                           ` Ian Campbell
2010-07-22  6:53                                   ` Stefan Assmann
2010-07-23  0:26                                     ` Casey Leedom
2010-07-23  8:08                                       ` Stefan Assmann
2010-07-23 16:35                                         ` Casey Leedom

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