[PATCH 1/4] net: Fix save software checksum complete
From: Tom Herbert <hidden>
Date: 2014-06-12 23:03:47
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
The logic introduced in commit 7e3cead5172927732f51fde
("net: Save software checksum complete") is not correct.
1) This patch restores code in __skb_checksum_complete_header except
for setting CHECKSUM_UNNECESSARY. This function may be caluculating
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.
Signed-off-by: Tom Herbert <redacted>
---
net/core/datagram.c | 34 ++++++++++++++++++++++++----------
1 file changed, 24 insertions(+), 10 deletions(-)
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 6b1c04c..cf6cc4e 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c@@ -739,22 +739,36 @@ __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); + } 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; + + return sum; } EXPORT_SYMBOL(__skb_checksum_complete);
--
2.0.0.526.g5318336