udp: Fix bogus UFO packet generation (26cde9f7) · Commits · 戴 / test

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

+6 −3

Original line number	Diff line number	Diff line
		@@ -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;

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