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

From	Stefan Richter <stefanr@s5r6.in-berlin.de>
Newsgroups	linux.kernel
Subject	[PATCH 3/3] firewire: net: max MTU off by one
Date	2016-11-02 21:20 +0100
Message-ID	<szaaR-2yB-1@gated-at.bofh.it> (permalink)
References	<sza1b-2sn-13@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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@s5r6.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/

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[PATCH 0/3] firewire: net: IP-over-1394 link fragmentation fixes Stefan Richter <stefanr@s5r6.in-berlin.de> - 2016-11-02 21:10 +0100
  [PATCH 2/3] firewire: net: fix fragmented datagram_size off-by-one Stefan Richter <stefanr@s5r6.in-berlin.de> - 2016-11-02 21:10 +0100
  [PATCH 3/3] firewire: net: max MTU off by one Stefan Richter <stefanr@s5r6.in-berlin.de> - 2016-11-02 21:20 +0100

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