On Tue, May 12, 2015 at 12:50 AM, Eric Dumazet [off-list ref] wrote:

On Mon, 2015-05-11 at 21:33 -0700, Eric Dumazet wrote:

quoted

On Mon, 2015-05-11 at 20:26 -0700, Tom Herbert wrote:

quoted

In flow dissector if a GRE header contains a keyid this is saved in the
new extra entropy field of flow_keys. The GRE keyid is then represented
in the flow hash function input.

Signed-off-by: Tom Herbert <redacted>
---
 include/net/flow_keys.h   |  1 +
 net/core/flow_dissector.c | 15 ++++++++++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/include/net/flow_keys.h b/include/net/flow_keys.h
index 906d47a..779e42f 100644
--- a/include/net/flow_keys.h
+++ b/include/net/flow_keys.h

@@ -28,6 +28,7 @@ struct flow_keys {
    u8      padding;
    u32     vlan_id:12,
            flow_label:20;
+   u32     extra_entropy;

    union {
            __be32 ports;

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index de71e42..025b91f 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c

@@ -195,8 +195,21 @@ ipv6:
                    nhoff += 4;
                    if (hdr->flags & GRE_CSUM)
                            nhoff += 4;
-                   if (hdr->flags & GRE_KEY)
+                   if (hdr->flags & GRE_KEY) {
+                           const __be32 *keyid;
+                           __be32 _keyid;
+
+                           keyid = __skb_header_pointer(skb, nhoff,
+                                                        sizeof(_keyid),
+                                                        data, hlen,
+                                                        &_keyid);
+                           if (!keyid)
+                                   return false;
+
+                           flow->extra_entropy ^= *keyid;

This probably should not please sparse ?

make C=2 CF=-D__CHECK_ENDIAN__  net/core/flow_dissector.o

BTW, you never addressed prior feedback about sparse errors :

include/linux/skbuff.h:3054:24: warning: incorrect type in return expression (different base types)
include/linux/skbuff.h:3054:24:    expected restricted __sum16
include/linux/skbuff.h:3054:24:    got int
include/linux/skbuff.h:3054:24: warning: incorrect type in return expression (different base types)
include/linux/skbuff.h:3054:24:    expected restricted __sum16
include/linux/skbuff.h:3054:24:    got int
include/linux/skbuff.h:3362:14: warning: incorrect type in assignment (different base types)
include/linux/skbuff.h:3362:14:    expected unsigned short [unsigned] [usertype] csum
include/linux/skbuff.h:3362:14:    got restricted __sum16
include/linux/skbuff.h:3367:16: warning: incorrect type in return expression (different base types)
include/linux/skbuff.h:3367:16:    expected restricted __sum16
include/linux/skbuff.h:3367:16:    got unsigned short [unsigned] [usertype] csum

commit 7e2b10c1e52ca37f ("net: Support for multiple checksums with gso")

Hi Eric,

I don't see these errors with sparse. How are you running it?

Thanks,
Tom

Thanks