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authorTom Herbert <therbert@google.com>2014-06-14 23:24:03 -0700
committerDavid S. Miller <davem@davemloft.net>2014-06-15 01:00:49 -0700
commit46fb51eb96cafb2c148b7b5119adb5e31a2bf3c4 (patch)
tree8deefff573270378b056f6f0915068a33578b2ad
parent4b28252cada3d0521ab59751f4240ecdfb9bba18 (diff)
net: Fix save software checksum complete
Geert reported issues regarding checksum complete and UDP. The logic introduced in commit 7e3cead5172927732f51fde ("net: Save software checksum complete") is not correct. This patch: 1) Restores code in __skb_checksum_complete_header except for setting CHECKSUM_UNNECESSARY. This function may be calculating checksum on something less than skb->len. 2) Adds saving checksum to __skb_checksum_complete. The full packet checksum 0..skb->len is calculated without adding in pseudo header. This value is saved in skb->csum and then the pseudo header is added to that to derive the checksum for validation. 3) In both __skb_checksum_complete_header and __skb_checksum_complete, set skb->csum_valid to whether checksum of zero was computed. This allows skb_csum_unnecessary to return true without changing to CHECKSUM_UNNECESSARY which was done previously. 4) Copy new csum related bits in __copy_skb_header. Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/core/datagram.c36
-rw-r--r--net/core/skbuff.c3
2 files changed, 29 insertions, 10 deletions
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 6b1c04ca1d50..488dd1a825c0 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -739,22 +739,38 @@ __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len)
__sum16 sum;
sum = csum_fold(skb_checksum(skb, 0, len, skb->csum));
- if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && !sum &&
- !skb->csum_complete_sw)
- netdev_rx_csum_fault(skb->dev);
-
- /* Save checksum complete for later use */
- skb->csum = sum;
- skb->ip_summed = CHECKSUM_COMPLETE;
- skb->csum_complete_sw = 1;
-
+ if (likely(!sum)) {
+ if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
+ !skb->csum_complete_sw)
+ netdev_rx_csum_fault(skb->dev);
+ }
+ skb->csum_valid = !sum;
return sum;
}
EXPORT_SYMBOL(__skb_checksum_complete_head);
__sum16 __skb_checksum_complete(struct sk_buff *skb)
{
- return __skb_checksum_complete_head(skb, skb->len);
+ __wsum csum;
+ __sum16 sum;
+
+ csum = skb_checksum(skb, 0, skb->len, 0);
+
+ /* skb->csum holds pseudo checksum */
+ sum = csum_fold(csum_add(skb->csum, csum));
+ if (likely(!sum)) {
+ if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
+ !skb->csum_complete_sw)
+ netdev_rx_csum_fault(skb->dev);
+ }
+
+ /* Save full packet checksum */
+ skb->csum = csum;
+ skb->ip_summed = CHECKSUM_COMPLETE;
+ skb->csum_complete_sw = 1;
+ skb->csum_valid = !sum;
+
+ return sum;
}
EXPORT_SYMBOL(__skb_checksum_complete);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index bf92824af3f7..9cd5344fad73 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -689,6 +689,9 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
new->ooo_okay = old->ooo_okay;
new->no_fcs = old->no_fcs;
new->encapsulation = old->encapsulation;
+ new->encap_hdr_csum = old->encap_hdr_csum;
+ new->csum_valid = old->csum_valid;
+ new->csum_complete_sw = old->csum_complete_sw;
#ifdef CONFIG_XFRM
new->sp = secpath_get(old->sp);
#endif

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