From 26cde9f7e2747b6d254b704594eed87ab959afa5 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Tue, 15 Jun 2010 01:52:25 +0000
Subject: [PATCH] udp: Fix bogus UFO packet generation
It has been reported that the new UFO software fallback path
fails under certain conditions with NFS. I tracked the problem
down to the generation of UFO packets that are smaller than the
MTU. The software fallback path simply discards these packets.
This patch fixes the problem by not generating such packets on
the UFO path.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/ip_output.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 9a4a6c96cb0d..041d41df1224 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -873,8 +873,10 @@ int ip_append_data(struct sock *sk,
!exthdrlen)
csummode = CHECKSUM_PARTIAL;
+ skb = skb_peek_tail(&sk->sk_write_queue);
+
inet->cork.length += length;
- if (((length> mtu) || !skb_queue_empty(&sk->sk_write_queue)) &&
+ if (((length > mtu) || (skb && skb_is_gso(skb))) &&
(sk->sk_protocol == IPPROTO_UDP) &&
(rt->u.dst.dev->features & NETIF_F_UFO)) {
err = ip_ufo_append_data(sk, getfrag, from, length, hh_len,
@@ -892,7 +894,7 @@ int ip_append_data(struct sock *sk,
* adding appropriate IP header.
*/
- if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
+ if (!skb)
goto alloc_new_skb;
while (length > 0) {
@@ -1121,7 +1123,8 @@ ssize_t ip_append_page(struct sock *sk, struct page *page,
return -EINVAL;
inet->cork.length += size;
- if ((sk->sk_protocol == IPPROTO_UDP) &&
+ if ((size + skb->len > mtu) &&
+ (sk->sk_protocol == IPPROTO_UDP) &&
(rt->u.dst.dev->features & NETIF_F_UFO)) {
skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
--
2.20.1