Commit da2033c2 authored Nov 30, 2010 by Eric Dumazet Committed by David S. Miller Dec 06, 2010

filter: add SKF_AD_RXHASH and SKF_AD_CPU



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>
Acked-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 539995d1

include/linux/filter.h

+3 −1

Original line number	Diff line number	Diff line
		@@ -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)

net/core/filter.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -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;

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