lkml.org 
[lkml]   [2014]   [May]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 3.12 061/103] net: core: don't account for udp header size when computing seglen
Date
From: Florian Westphal <fw@strlen.de>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

[ Upstream commit 6d39d589bb76ee8a1c6cde6822006ae0053decff ]

In case of tcp, gso_size contains the tcpmss.

For UFO (udp fragmentation offloading) skbs, gso_size is the fragment
payload size, i.e. we must not account for udp header size.

Otherwise, when using virtio drivers, a to-be-forwarded UFO GSO packet
will be needlessly fragmented in the forward path, because we think its
individual segments are too large for the outgoing link.

Fixes: fe6cc55f3a9a053 ("net: ip, ipv6: handle gso skbs in forwarding path")
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: Tobias Brunner <tobias@strongswan.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
net/core/skbuff.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 21571dc4f2df..f69f2ed1dbc3 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3535,12 +3535,14 @@ EXPORT_SYMBOL_GPL(skb_scrub_packet);
unsigned int skb_gso_transport_seglen(const struct sk_buff *skb)
{
const struct skb_shared_info *shinfo = skb_shinfo(skb);
- unsigned int hdr_len;

if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
- hdr_len = tcp_hdrlen(skb);
- else
- hdr_len = sizeof(struct udphdr);
- return hdr_len + shinfo->gso_size;
+ return tcp_hdrlen(skb) + shinfo->gso_size;
+
+ /* UFO sets gso_size to the size of the fragmentation
+ * payload, i.e. the size of the L4 (UDP) header is already
+ * accounted for.
+ */
+ return shinfo->gso_size;
}
EXPORT_SYMBOL_GPL(skb_gso_transport_seglen);
--
1.9.3


\
 
 \ /
  Last update: 2014-05-29 17:21    [W:0.348 / U:0.176 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site