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netfilter: xt_NFQUEUE: introduce CPU fanout

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Current NFQUEUE target uses a hash, computed over source and
destination address (and other parameters), for steering the packet
to the actual NFQUEUE. This, however forgets about the fact that the
packet eventually is handled by a particular CPU on user request.

If E. g.

  1) IRQ affinity is used to handle packets on a particular CPU already
     (both single-queue or multi-queue case)

and/or

  2) RPS is used to steer packets to a specific softirq

the target easily chooses an NFQUEUE which is not handled by a process
pinned to the same CPU.

The idea is therefore to use the CPU index for determining the
NFQUEUE handling the packet.

E. g. when having a system with 4 CPUs, 4 MQ queues and 4 NFQUEUEs it
looks like this:

 +-----+  +-----+  +-----+  +-----+
 |NFQ#0|  |NFQ#1|  |NFQ#2|  |NFQ#3|
 +-----+  +-----+  +-----+  +-----+
    ^        ^        ^        ^
    |        |NFQUEUE |        |
    +        +        +        +
 +-----+  +-----+  +-----+  +-----+
 |rx-0 |  |rx-1 |  |rx-2 |  |rx-3 |
 +-----+  +-----+  +-----+  +-----+

The NFQUEUEs not necessarily have to start with number 0, setups with
less NFQUEUEs than packet-handling CPUs are not a problem as well.

This patch extends the NFQUEUE target to accept a new
NFQ_FLAG_CPU_FANOUT flag. If this is specified the target uses the
CPU index for determining the NFQUEUE being used. I have to introduce
rev3 for this. The 'flags' are folded into _v2 'bypass'.

By changing the way which queue is assigned, I'm able to improve the
performance if the processes reading on the NFQUEUs are pinned
correctly.

Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
holger@eitzenberger.org 2013-03-23 10:04:03 +00:00 committed by Pablo Neira Ayuso
parent f016588861
commit 8746ddcf12
2 changed files with 48 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
include/uapi/linux/netfilter/xt_NFQUEUE.h
View File

@ -26,4 +26,13 @@ struct xt_NFQ_info_v2 {
__u16 bypass;
};
struct xt_NFQ_info_v3 {
__u16 queuenum;
__u16 queues_total;
__u16 flags;
#define NFQ_FLAG_BYPASS 0x01 /* for compatibility with v2 */
#define NFQ_FLAG_CPU_FANOUT 0x02 /* use current CPU (no hashing) */
#define NFQ_FLAG_MASK 0x03
};
#endif /* _XT_NFQ_TARGET_H */

41
net/netfilter/xt_NFQUEUE.c
View File

@ -108,7 +108,7 @@ nfqueue_tg_v2(struct sk_buff *skb, const struct xt_action_param *par)
static int nfqueue_tg_check(const struct xt_tgchk_param *par)
{
const struct xt_NFQ_info_v2 *info = par->targinfo;
const struct xt_NFQ_info_v3 *info = par->targinfo;
u32 maxid;
if (unlikely(!rnd_inited)) {
@ -125,11 +125,39 @@ static int nfqueue_tg_check(const struct xt_tgchk_param *par)
info->queues_total, maxid);
return -ERANGE;
}
if (par->target->revision == 2 && info->bypass > 1)
if (par->target->revision == 2 && info->flags > 1)
return -EINVAL;
if (par->target->revision == 3 && info->flags & ~NFQ_FLAG_MASK)
return -EINVAL;
return 0;
}
static unsigned int
nfqueue_tg_v3(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct xt_NFQ_info_v3 *info = par->targinfo;
u32 queue = info->queuenum;
if (info->queues_total > 1) {
if (info->flags & NFQ_FLAG_CPU_FANOUT) {
int cpu = smp_processor_id();
queue = info->queuenum + cpu % info->queues_total;
} else {
if (par->family == NFPROTO_IPV4)
queue = (((u64) hash_v4(skb) * info->queues_total) >>
32) + queue;
#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
else if (par->family == NFPROTO_IPV6)
queue = (((u64) hash_v6(skb) * info->queues_total) >>
32) + queue;
#endif
}
}
return NF_QUEUE_NR(queue);
}
static struct xt_target nfqueue_tg_reg[] __read_mostly = {
{
.name = "NFQUEUE",
@ -156,6 +184,15 @@ static struct xt_target nfqueue_tg_reg[] __read_mostly = {
.targetsize = sizeof(struct xt_NFQ_info_v2),
.me = THIS_MODULE,
},
{
.name = "NFQUEUE",
.revision = 3,
.family = NFPROTO_UNSPEC,
.checkentry = nfqueue_tg_check,
.target = nfqueue_tg_v3,
.targetsize = sizeof(struct xt_NFQ_info_v3),
.me = THIS_MODULE,
},
};
static int __init nfqueue_tg_init(void)