| From | Ben Hutchings <> | Date | Sat, 07 Jun 2014 02:26:28 +0100 | Subject | [PATCH 3.2 08/92] net: core: don't account for udp header size when computing seglen |
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3.2.60-rc1 review patch. If anyone has any objections, please let me know.
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From: Florian Westphal <fw@strlen.de>
[ 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: Ben Hutchings <ben@decadent.org.uk> --- 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 8ac4a0f..8ae2e43 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3197,12 +3197,14 @@ EXPORT_SYMBOL(__skb_warn_lro_forwarding); 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);
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