| From foo@baz Wed May 28 21:03:54 PDT 2014 |
| From: Florian Westphal <fw@strlen.de> |
| Date: Wed, 9 Apr 2014 10:28:50 +0200 |
| Subject: net: core: don't account for udp header size when computing seglen |
| |
| 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/core/skbuff.c | 12 +++++++----- |
| 1 file changed, 7 insertions(+), 5 deletions(-) |
| |
| --- a/net/core/skbuff.c |
| +++ b/net/core/skbuff.c |
| @@ -3951,12 +3951,14 @@ 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); |
