[PATCH net-next-2.6] filter: add SKF_AD_RXHASH and SKF_AD_CPU

Eric Dumazet
2010-12-01T07:46:02Z

Add SKF_AD_RXHASH and SKF_AD_CPU to filter ancillary mechanism,
to be able to build advanced filters.

This can help spreading packets on several sockets with a fast
selection, after RPS dispatch to N cpus for example, or to catch a
percentage of flows in one queue.

tcpdump -s 500 "cpu = 1" :

[0] ld CPU
[1] jeq #1 jt 2 jf 3
[2] ret #500
[3] ret #0

# take 12.5 % of flows (average)
tcpdump -s 1000 "rxhash & 7 = 2" :

[0] ld RXHASH
[1] and #7
[2] jeq #2 jt 3 jf 4
[3] ret #1000
[4] ret #0

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Rui <wirelesser@gmail.com>
---
include/linux/filter.h | 4 +++-
net/core/filter.c | 6 ++++++
2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 447a775..5334ada 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -124,7 +124,9 @@ struct sock_fprog { /* Required for SO_ATTACH_FILTER. */
#define SKF_AD_MARK 20
#define SKF_AD_QUEUE 24
#define SKF_AD_HATYPE 28
-#define SKF_AD_MAX 32
+#define SKF_AD_RXHASH 32
+#define SKF_AD_CPU 36
+#define SKF_AD_MAX 40
#define SKF_NET_OFF (-0x100000)
#define SKF_LL_OFF (-0x200000)

diff --git a/net/core/filter.c b/net/core/filter.c
index a44d27f..054e286 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -375,6 +375,12 @@ load_b:
return 0;
A = skb->dev->type;
continue;
+ case SKF_AD_RXHASH:
+ A = skb->rxhash;
+ continue;
+ case SKF_AD_CPU:
+ A = raw_smp_processor_id();
+ continue;
case SKF_AD_NLATTR: {
struct nlattr *nla;