netdev - Re: [resend] Passive OS fingerprint xtables match.

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Message-ID: <20090604145009.GB18251@ioremap.net>
Date:	Thu, 4 Jun 2009 18:50:09 +0400
From:	Evgeniy Polyakov <zbr@...emap.net>
To:	Patrick McHardy <kaber@...sh.net>
Cc:	netdev@...r.kernel.org, David Miller <davem@...emloft.net>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Netfilter Development Mailinglist 
	<netfilter-devel@...r.kernel.org>,
	Jan Engelhardt <jengelh@...ozas.de>
Subject: Re: [resend] Passive OS fingerprint xtables match.

On Thu, Jun 04, 2009 at 03:16:17PM +0200, Patrick McHardy (kaber@...sh.net) wrote:
> Exactly. But please verify that by reordering, you're not moving
> the more commonly used members out of the first cacheline.

That's what I ended up with. arptable does not use match entries. Did I
miss others?

As of cache line alignment - I moved the only writable member at the end
of the structure, so it should even improve things a bit, although I
really do not think this will ever be noticeble.

--

Added hook number into match extension parameter structure.

Signed-off-by: Evgeniy Polyakov <zbr@...emap.net>

diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index 7b1a652..65a08ae 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -184,9 +184,10 @@ struct xt_counters_info
  * @matchinfo:	per-match data
  * @fragoff:	packet is a fragment, this is the data offset
  * @thoff:	position of transport header relative to skb->data
- * @hotdrop:	drop packet if we had inspection problems
+ * @hook:	hook number given packet came from
  * @family:	Actual NFPROTO_* through which the function is invoked
  * 		(helpful when match->family == NFPROTO_UNSPEC)
+ * @hotdrop:	drop packet if we had inspection problems
  */
 struct xt_match_param {
 	const struct net_device *in, *out;
@@ -194,8 +195,9 @@ struct xt_match_param {
 	const void *matchinfo;
 	int fragoff;
 	unsigned int thoff;
-	bool *hotdrop;
+	unsigned int hooknum;
 	u_int8_t family;
+	bool *hotdrop;
 };
 
 /**
diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 820252a..db2540e 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -164,7 +164,7 @@ unsigned int ebt_do_table (unsigned int hook, struct sk_buff *skb,
 	mtpar.in      = tgpar.in  = in;
 	mtpar.out     = tgpar.out = out;
 	mtpar.hotdrop = &hotdrop;
-	tgpar.hooknum = hook;
+	mtpar.hooknum = tgpar.hooknum = hook;
 
 	read_lock_bh(&table->lock);
 	private = table->private;
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 810c0b6..385e4a0 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -335,7 +335,7 @@ ipt_do_table(struct sk_buff *skb,
 	mtpar.in      = tgpar.in  = in;
 	mtpar.out     = tgpar.out = out;
 	mtpar.family  = tgpar.family = NFPROTO_IPV4;
-	tgpar.hooknum = hook;
+	mtpar.hooknum = tgpar.hooknum = hook;
 
 	IP_NF_ASSERT(table->valid_hooks & (1 << hook));
 
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 800ae85..d603ae4 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -361,7 +361,7 @@ ip6t_do_table(struct sk_buff *skb,
 	mtpar.in      = tgpar.in  = in;
 	mtpar.out     = tgpar.out = out;
 	mtpar.family  = tgpar.family = NFPROTO_IPV6;
-	tgpar.hooknum = hook;
+	mtpar.hooknum = tgpar.hooknum = hook;
 
 	IP_NF_ASSERT(table->valid_hooks & (1 << hook));
 


-- 
	Evgeniy Polyakov
--
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