From: Michael Tokarev <mjt@tls•msk.ru>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: David Lamparter <equinox@diac24•net>,
jeffrey.t.kirsher@intel•com, netdev <netdev@vger•kernel.org>
Subject: Re: e100 + VLANs?
Date: Tue, 11 Oct 2011 15:59:06 +0400 [thread overview]
Message-ID: <4E942F8A.90205@msgid.tls.msk.ru> (raw)
In-Reply-To: <CAL4WiiphpyizVaNkvOdJp1+UK53TkGw9RXnC-vzH7fTNpBAAEA@mail.gmail.com>
11.10.2011 15:25, Eric Dumazet wrote:
>> So, is that a hardware limitation?
>
> Its a driver bug
>
> This comes from fact that sizeof(struct rfd) = 16
>
> and VLAN_ETH_FRAME_LEN is 1518
>
> driver mixes VLAN_ETH_FRAME_LEN and 1500+4+sizeof(struct rfd) (1520, not 1518)
>
> It therefore misses 2 bytes for large frames (VLAN tagged)
>
> Fix is to remove VLAN_ETH_FRAME_LEN references for good...
>
> diff --git a/drivers/net/e100.c b/drivers/net/e100.c
> index c1352c6..3287d31 100644
Hmm. This does not _exactly_ work.
I applied it on top of 2.6.32, patch applied but with some fuzz - I checked
manually and it appears to be ok.
Now, with this patch applied, I see on the e100 side:
00:1f:c6:ef:e5:1b > 00:90:27:30:6d:1c, ethertype 802.1Q (0x8100), length 1504: vlan 6, p 0, ethertype IPv4, truncated-ip - 1 bytes missing! (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 1487)
10.48.6.1 > 10.48.6.2: ICMP echo request, id 27613, seq 6, length 1467
when pinging it with -s 1459 (1487 total size).
I added extra +40 for RFD_BUF_LEN define and recompiled
(this resulted in RFD_BUF_LEN=1560, - I've added a printk
just to be sure).
Now I see the same effect as before the patch: maximum
packet size that goes and can be seen on the e100 side
is 1468(1496) (ping), which results in this on e100 side:
15:54:44.830941 00:1f:c6:ef:e5:1b > 00:90:27:30:6d:1c, ethertype 802.1Q (0x8100), length 1514: vlan 6, p 0, ethertype IPv4, (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 1496)
10.48.6.1 > 10.48.6.2: ICMP echo request, id 28735, seq 4, length 1476
15:54:44.831025 00:90:27:30:6d:1c > 00:1f:c6:ef:e5:1b, ethertype 802.1Q (0x8100), length 1514: vlan 6, p 0, ethertype IPv4, (tos 0x0, ttl 64, id 12010, offset 0, flags [none], proto ICMP (1), length 1496)
10.48.6.2 > 10.48.6.1: ICMP echo reply, id 28735, seq 4, length 1476
(and it works). With -s 1469, no ICMP packets can be seen
on e100 side.
So it still may be the hardware... :)
Thank you!
/mjt
next prev parent reply other threads:[~2011-10-11 11:59 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-08 10:08 e100 + VLANs? Michael Tokarev
2011-10-08 16:24 ` Eric Dumazet
2011-10-08 18:34 ` Jeff Kirsher
2011-10-10 10:19 ` David Lamparter
2011-10-10 14:57 ` Michael Tokarev
2011-10-10 15:05 ` Eric Dumazet
2011-10-10 15:13 ` David Lamparter
2011-10-10 15:23 ` Eric Dumazet
2011-10-10 15:28 ` David Lamparter
2011-10-10 15:50 ` Eric Dumazet
2011-10-10 16:51 ` Michael Tokarev
[not found] ` <4E932278.8010802@tls.msk.ru>
2011-10-11 9:51 ` Michael Tokarev
2011-10-11 11:25 ` Eric Dumazet
2011-10-11 11:59 ` Michael Tokarev [this message]
2011-10-11 12:04 ` Eric Dumazet
2011-10-11 12:56 ` Michael Tokarev
2011-10-11 15:29 ` David Lamparter
2011-10-11 23:38 ` Jesse Brandeburg
2011-10-13 9:22 ` Michael Tokarev
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