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From: ebiederm@xmission.com (Eric W. Biederman)
To: Or Gerlitz <or.gerlitz@gmail.com>
Cc: Ali Ayoub <ali@mellanox.com>, David Miller <davem@davemloft.net>,
	ogerlitz@mellanox.com, roland@kernel.org, netdev@vger.kernel.org,
	sean.hefty@intel.com, erezsh@mellanox.co.il, dledford@redhat.com
Subject: Re: [PATCH V2 09/12] net/eipoib: Add main driver functionality
Date: Wed, 08 Aug 2012 01:36:16 -0700	[thread overview]
Message-ID: <87hasd7pbz.fsf@xmission.com> (raw)
In-Reply-To: <CAJZOPZ+W0wfa38LejXt0gvBNa8Q6pWVZOs7xctHGRQXHAeMYPQ@mail.gmail.com> (Or Gerlitz's message of "Wed, 8 Aug 2012 09:04:55 +0300")

Or Gerlitz <or.gerlitz@gmail.com> writes:

> Eric W. Biederman <ebiederm@xmission.com> wrote:
>>> Ali Ayoub <ali@mellanox.com> writes:
>
>>> Among other things, the main benefit we're targeting is to allow IPoE
>>> traffic within the VM to go through the (Ethernet) vBridge down to the
>>> eIPoIB PIF, and eventually to IPoIB and to the IB network.
>
>> Oh yes.  It just occurred to me there is huge problem with eIPoIB as
>> currently presented in these patches.  It breaks DHCPv4 the same way
>> it breaks ARP, but DHCPv4 is not fixed up.
>
> To put things in place, DHCPv4 is supported with eIPoIB, the DHCP
> UDP/IP payload  isn't touched, only need to set the BOOTP broadcast
> flag in the dhcp server config file.

Wrong.  DHCPv4 is broken over eIPoIB. 

Coming from ethernet
htype == 1 not 32 as required by RFC4390
hlen == 6 not 0 as required by RFC4390
The chaddr field is has 6 bytes of the ethernet mac address not the
required 16 bytes of 0.

The client-identifier field is optional over ethernet.

An ethernet DHCPv4 client simply does not generate a dhcp packet that
conforms to RFC4390.

Therefore DHCPv4 over eIPoIB is broken, and a dhcp server or relay
may reasonably look at the DHCP packet and drop it because it is
garbage.

You might find a forgiving dhcp server that doesn't drop insane packets
on the floor and tries to make things work.

I am sorry.  eIPoIB is broken as designed.  eIPoIB most assuredly is not
compatible with ethernet.  eIPoIB most definitely does not work even for
the general case of transporing IP traffic.  Claiming that eIPoIB is any
else is a lie.

Eric

  reply	other threads:[~2012-08-08  8:45 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-01 17:09 [PATCH V2 00/12] Add Ethernet IPoIB driver Or Gerlitz
2012-08-01 17:09 ` [PATCH V2 01/12] IB/ipoib: Add rtnl_link_ops support Or Gerlitz
2012-08-01 17:09 ` [PATCH V2 02/12] IB/ipoib: Add support for clones / multiple childs on the same partition Or Gerlitz
2012-08-01 17:09 ` [PATCH V2 03/12] include/linux: Add private flags for IPoIB interfaces Or Gerlitz
2012-08-01 17:09 ` [PATCH V2 04/12] IB/ipoib: Add support for acting as VIF Or Gerlitz
2012-08-01 17:09 ` [PATCH V2 05/12] net: Add ndo_set_vif_param operation to serve eIPoIB VIFs Or Gerlitz
2012-08-02  0:17   ` Ben Hutchings
2012-08-02  8:25     ` Erez Shitrit
2012-08-01 17:09 ` [PATCH V2 06/12] net/core: Add rtnetlink support to vif parameters Or Gerlitz
2012-08-02  0:20   ` Ben Hutchings
2012-08-02 15:29     ` Erez Shitrit
2012-08-01 17:09 ` [PATCH V2 07/12] net/eipoib: Add private header file Or Gerlitz
2012-08-01 17:09 ` [PATCH V2 08/12] net/eipoib: Add ethtool file support Or Gerlitz
2012-08-02  0:22   ` Ben Hutchings
2012-08-02  8:35     ` Erez Shitrit
2012-08-02 15:42       ` Ben Hutchings
2012-08-01 17:09 ` [PATCH V2 09/12] net/eipoib: Add main driver functionality Or Gerlitz
2012-08-02 17:15   ` Eric W. Biederman
2012-08-03 20:31     ` Ali Ayoub
2012-08-03 21:33       ` David Miller
2012-08-03 22:39         ` Ali Ayoub
2012-08-03 23:36           ` David Miller
2012-08-04 21:23             ` Or Gerlitz
2012-08-04 21:44               ` Or Gerlitz
2012-08-04 23:19                 ` Eric W. Biederman
2012-08-07  0:14             ` Ali Ayoub
2012-08-07  0:44               ` Eric W. Biederman
2012-08-07  1:21                 ` Re[2]: " Naoto MATSUMOTO
2012-08-15  9:10                   ` Re[3]: " Naoto MATSUMOTO
2012-08-07  3:33                 ` Eric W. Biederman
2012-08-08  6:04                   ` Or Gerlitz
2012-08-08  8:36                     ` Eric W. Biederman [this message]
2012-08-09  4:06                       ` Or Gerlitz
2012-08-12 14:05                         ` Michael S. Tsirkin
2012-08-07  3:37                 ` Joseph Glanville
2012-08-08  7:32                 ` Or Gerlitz
2012-08-08  9:17                   ` Eric W. Biederman
2012-08-09  4:34                     ` Or Gerlitz
2012-08-12 10:36                       ` Michael S. Tsirkin
2012-08-04  0:02           ` Ali Ayoub
2012-08-04  0:05             ` David Miller
2012-08-04  1:34             ` Eric W. Biederman
2012-08-04 21:33               ` Or Gerlitz
2012-08-05 18:50     ` Michael S. Tsirkin
2012-08-08  5:23       ` Or Gerlitz
2012-08-12 10:22         ` Michael S. Tsirkin
2012-08-12 13:09           ` Or Gerlitz
2012-08-12 13:41             ` Michael S. Tsirkin
2012-08-12 13:15           ` Or Gerlitz
2012-08-12 13:55             ` Michael S. Tsirkin
2012-08-12 14:13               ` Or Gerlitz
2012-08-12 20:54                 ` Michael S. Tsirkin
2012-08-14  8:44                   ` Or Gerlitz
2012-08-20 18:57                   ` Michael S. Tsirkin
2012-08-23  6:45                     ` Or Gerlitz
2012-08-14  7:41               ` Or Gerlitz
2012-08-12 10:54         ` Michael S. Tsirkin
2012-08-12 13:19           ` Or Gerlitz
2012-08-12 15:40         ` Eric W. Biederman
2012-08-13  8:33           ` Or Gerlitz
2012-08-13 16:08             ` Eric W. Biederman
2012-09-03 20:53       ` Or Gerlitz
2012-09-03 21:22         ` Michael S. Tsirkin
2012-09-04 18:50           ` Or Gerlitz
2012-09-04 19:31             ` Eric W. Biederman
2012-09-04 19:47               ` Or Gerlitz
2012-09-04 21:21             ` Michael S. Tsirkin
2012-09-04 18:57           ` Or Gerlitz
2012-08-01 17:09 ` [PATCH V2 10/12] net/eipoib: Add sysfs support Or Gerlitz
2012-08-01 17:09 ` [PATCH V2 11/12] net/eipoib: Add Makefile, Kconfig and MAINTAINERS entries Or Gerlitz
2012-08-01 17:09 ` [PATCH V2 12/12] IB/ipoib: Add support for transmission of skbs w.o dst/neighbour Or Gerlitz

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