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authorTom Herbert <therbert@google.com>2015-02-11 03:30:28 +0300
committerDavid S. Miller <davem@davemloft.net>2015-02-12 02:12:10 +0300
commit6edec0e61b1e52f9144935d28c9088f5b202e61c (patch)
tree6c0be33e56894f48033f6fffbe253bea3852e91c /include/linux/skbuff.h
parent26c4f7da3e413da697a7beb22ad496390eda7da0 (diff)
downloadlinux-6edec0e61b1e52f9144935d28c9088f5b202e61c.tar.xz
net: Clarify meaning of CHECKSUM_PARTIAL for receive path
The current meaning of CHECKSUM_PARTIAL for validating checksums is that _all_ checksums in the packet are considered valid. However, in the manner that CHECKSUM_PARTIAL is set only the checksum at csum_start+csum_offset and any preceding checksums may be considered valid. If there are checksums in the packet after csum_offset it is possible they have not been verfied. This patch changes CHECKSUM_PARTIAL logic in skb_csum_unnecessary and __skb_gro_checksum_validate_needed to only considered checksums referring to csum_start and any preceding checksums (with starting offset before csum_start) to be verified. Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/skbuff.h')
-rw-r--r--include/linux/skbuff.h17
1 files changed, 12 insertions, 5 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 1bb36edb66b9..da6028a50687 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -83,11 +83,15 @@
*
* CHECKSUM_PARTIAL:
*
- * This is identical to the case for output below. This may occur on a packet
+ * A checksum is set up to be offloaded to a device as described in the
+ * output description for CHECKSUM_PARTIAL. This may occur on a packet
* received directly from another Linux OS, e.g., a virtualized Linux kernel
- * on the same host. The packet can be treated in the same way as
- * CHECKSUM_UNNECESSARY, except that on output (i.e., forwarding) the
- * checksum must be filled in by the OS or the hardware.
+ * on the same host, or it may be set in the input path in GRO or remote
+ * checksum offload. For the purposes of checksum verification, the checksum
+ * referred to by skb->csum_start + skb->csum_offset and any preceding
+ * checksums in the packet are considered verified. Any checksums in the
+ * packet that are after the checksum being offloaded are not considered to
+ * be verified.
*
* B. Checksumming on output.
*
@@ -2915,7 +2919,10 @@ __sum16 __skb_checksum_complete(struct sk_buff *skb);
static inline int skb_csum_unnecessary(const struct sk_buff *skb)
{
- return ((skb->ip_summed & CHECKSUM_UNNECESSARY) || skb->csum_valid);
+ return ((skb->ip_summed == CHECKSUM_UNNECESSARY) ||
+ skb->csum_valid ||
+ (skb->ip_summed == CHECKSUM_PARTIAL &&
+ skb_checksum_start_offset(skb) >= 0));
}
/**