net: avoid skb_warn_bad_offload false positives on UFO

[ Upstream commit 8d63bee643f1fb53e472f0e135cae4eb99d62d19 ]

skb_warn_bad_offload triggers a warning when an skb enters the GSO
stack at __skb_gso_segment that does not have CHECKSUM_PARTIAL
checksum offload set.

Commit b2504a5dbef3 ("net: reduce skb_warn_bad_offload() noise")
observed that SKB_GSO_DODGY producers can trigger the check and
that passing those packets through the GSO handlers will fix it
up. But, the software UFO handler will set ip_summed to
CHECKSUM_NONE.

When __skb_gso_segment is called from the receive path, this
triggers the warning again.

Make UFO set CHECKSUM_UNNECESSARY instead of CHECKSUM_NONE. On
Tx these two are equivalent. On Rx, this better matches the
skb state (checksum computed), as CHECKSUM_NONE here means no
checksum computed.

See also this thread for context:
http://patchwork.ozlabs.org/patch/799015/

Fixes: b2504a5dbef3 ("net: reduce skb_warn_bad_offload() noise")
Change-Id: I80567d5c09be96b7c329aeb46b81985dd92b1761
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Willem de Bruijn 2017-08-08 14:22:55 -04:00 committed by syphyr
parent 80677e6dda
commit b659cfd51a
3 changed files with 3 additions and 3 deletions

View File

@ -2343,7 +2343,7 @@ static inline bool skb_needs_check(struct sk_buff *skb, bool tx_path)
{
if (tx_path)
return skb->ip_summed != CHECKSUM_PARTIAL &&
skb->ip_summed != CHECKSUM_NONE;
skb->ip_summed != CHECKSUM_UNNECESSARY;
return skb->ip_summed == CHECKSUM_NONE;
}

View File

@ -2419,7 +2419,7 @@ struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
csum = skb_checksum(skb, offset, skb->len - offset, 0);
offset += skb->csum_offset;
*(__sum16 *)(skb->data + offset) = csum_fold(csum);
skb->ip_summed = CHECKSUM_NONE;
skb->ip_summed = CHECKSUM_UNNECESSARY;
segs = skb_segment(skb, features);
}

View File

@ -82,7 +82,7 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
csum = skb_checksum(skb, offset, skb->len - offset, 0);
offset += skb->csum_offset;
*(__sum16 *)(skb->data + offset) = csum_fold(csum);
skb->ip_summed = CHECKSUM_NONE;
skb->ip_summed = CHECKSUM_UNNECESSARY;
/* Check if there is enough headroom to insert fragment header. */
tnl_hlen = skb_tnl_header_len(skb);