[009/107] ipv6: Add GSO support on forwarding path

From: Greg KH
Date: Wed Nov 02 2011 - 21:34:20 EST


2.6.32-longterm review patch. If anyone has any objections, please let us know.

------------------

From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

commit 0aa68271510ae2b221d4b60892103837be63afe4 upstream.

Currently we disallow GSO packets on the IPv6 forward path.
This patch fixes this.

Note that I discovered that our existing GSO MTU checks (e.g.,
IPv4 forwarding) are buggy in that they skip the check altogether,
when they really should be checking gso_size + header instead.

I have also been lazy here in that I haven't bothered to segment
the GSO packet by hand before generating an ICMP message. Someone
should add that to be 100% correct.

Reported-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Apollon Oikonomopoulos <apoikos@xxxxxxxxx>
Signed-off-by: Faidon Liambotis <paravoid@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
net/ipv6/ip6_output.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -510,7 +510,7 @@ int ip6_forward(struct sk_buff *skb)
}
}

- if (skb->len > dst_mtu(dst)) {
+ if (skb->len > dst_mtu(dst) && !skb_is_gso(skb)) {
/* Again, force OUTPUT device used as source address */
skb->dev = dst->dev;
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, dst_mtu(dst), skb->dev);


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