Date: Wed, 24 Jan 2007 19:13:09 +0000 (GMT) From: wpaul@FreeBSD.ORG (Bill Paul) To: wpaul@FreeBSD.ORG (Bill Paul) Cc: pyunyh@gmail.com, freebsd-current@freebsd.org, r.c.ladan@gmail.com Subject: Re: Call for re(4) checksum offload testers. Message-ID: <20070124191309.D17A016A403@hub.freebsd.org> In-Reply-To: <20070124190203.E80FB16A403@hub.freebsd.org> from Bill Paul at "Jan 24, 2007 07:02:03 pm"
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> Based on testing with my sample adapters, I think the right thing to do
> is skip the software padding in the TCP case. It appears that even
> the older 8169 adapters that botch the small IP fragment case will correctly
> handle this small TCP segment case. I'm attaching a patch which should
> fix the problem without breaking the workaround for other NICs. If you
> verify that this patch also fixes your problem, then this patch should
> be checked in instead of the other one.
Crap... I just realized as I hit the send button that I was testing
for the wrong flag in the rl_flags field. I'm sending the patch again,
hopefully correct this time.
-Bill
--
=============================================================================
-Bill Paul (510) 749-2329 | Senior Engineer, Master of Unix-Fu
wpaul@windriver.com | Wind River Systems
=============================================================================
<adamw> you're just BEGGING to face the moose
=============================================================================
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--- if_re.c.orig Wed Jan 24 10:38:14 2007
+++ if_re.c Wed Jan 24 11:06:21 2007
@@ -2075,9 +2075,13 @@
* the mbuf chain has too many fragments so the coalescing code
* below can assemble the packet into a single buffer that's
* padded out to the mininum frame size.
+ *
+ * Note: this appears unnecessary for TCP, and doing it for TCP
+ * with PCIe adapters seems to result in bad checksums.
*/
- if (arg.rl_flags && (*m_head)->m_pkthdr.len < RL_MIN_FRAMELEN)
+ if (arg.rl_flags && !(arg.rl_flags & RL_TDESC_CMD_TCPCSUM) &&
+ (*m_head)->m_pkthdr.len < RL_MIN_FRAMELEN)
error = EFBIG;
else
error = bus_dmamap_load_mbuf(sc->rl_ldata.rl_mtag, map,
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