linux-kernel - [PATCH 3/3] firewire: net: max MTU off by one

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Date:   Wed, 2 Nov 2016 21:09:44 +0100
From:   Stefan Richter <stefanr@...6.in-berlin.de>
To:     linux1394-devel@...ts.sourceforge.net
Cc:     linux-kernel@...r.kernel.org, Eyal Itkin <eyal.itkin@...il.com>
Subject: [PATCH 3/3] firewire: net: max MTU off by one

The latest max_mtu patch missed that datagram_size is actually one less
than the datagram's Total Length.

Fixes: 357f4aae859b ("firewire: net: really fix maximum possible MTU")
Signed-off-by: Stefan Richter <stefanr@...6.in-berlin.de>
---
To be applied after net-next was merged.

 drivers/firewire/net.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/firewire/net.c b/drivers/firewire/net.c
index 5d3640264f2d..655c259e37fd 100644
--- a/drivers/firewire/net.c
+++ b/drivers/firewire/net.c
@@ -1482,9 +1482,14 @@ static int fwnet_probe(struct fw_unit *unit,
 		goto out;
 	dev->local_fifo = dev->handler.offset;
 
+	/*
+	 * default MTU: RFC 2734 cl. 4, RFC 3146 cl. 4
+	 * maximum MTU: RFC 2734 cl. 4.2, fragment encapsulation header's
+	 *              maximum possible datagram_size + 1 = 0xfff + 1
+	 */
 	net->mtu = 1500U;
 	net->min_mtu = ETH_MIN_MTU;
-	net->max_mtu = 0xfff;
+	net->max_mtu = 4096U;
 
 	/* Set our hardware address while we're at it */
 	ha = (union fwnet_hwaddr *)net->dev_addr;
-- 
Stefan Richter
-======----- =-== ---=-
http://arcgraph.de/sr/