From 45e934262d3d0175d848549f865132ca5f4bd19c Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Thu, 9 Apr 2009 19:43:19 +0000
Subject: netfilter: speed up packet matching by allowing default rules to
bypass the common checks
SVN-Revision: 15177
---
.../110-netfilter_match_speedup.patch | 74 ++++++++++++++++++++++
1 file changed, 74 insertions(+)
create mode 100644 target/linux/generic-2.6/patches-2.6.28/110-netfilter_match_speedup.patch
diff --git a/target/linux/generic-2.6/patches-2.6.28/110-netfilter_match_speedup.patch b/target/linux/generic-2.6/patches-2.6.28/110-netfilter_match_speedup.patch
new file mode 100644
index 0000000000..a8a49ec65e
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.28/110-netfilter_match_speedup.patch
@@ -0,0 +1,74 @@
+--- a/include/linux/netfilter_ipv4/ip_tables.h
++++ b/include/linux/netfilter_ipv4/ip_tables.h
+@@ -62,6 +62,7 @@ struct ipt_ip {
+ #define IPT_F_FRAG 0x01 /* Set if rule is a fragment rule */
+ #define IPT_F_GOTO 0x02 /* Set if jump is a goto */
+ #define IPT_F_MASK 0x03 /* All possible flag bits mask. */
++#define IPT_F_NO_DEF_MATCH 0x80 /* Internal: no default match rules present */
+
+ /* Values for "inv" field in struct ipt_ip. */
+ #define IPT_INV_VIA_IN 0x01 /* Invert the sense of IN IFACE. */
+--- a/net/ipv4/netfilter/ip_tables.c
++++ b/net/ipv4/netfilter/ip_tables.c
+@@ -88,6 +88,9 @@ ip_packet_match(const struct iphdr *ip,
+
+ #define FWINV(bool, invflg) ((bool) ^ !!(ipinfo->invflags & (invflg)))
+
++ if (ipinfo->flags & IPT_F_NO_DEF_MATCH)
++ return true;
++
+ if (FWINV((ip->saddr&ipinfo->smsk.s_addr) != ipinfo->src.s_addr,
+ IPT_INV_SRCIP)
+ || FWINV((ip->daddr&ipinfo->dmsk.s_addr) != ipinfo->dst.s_addr,
+@@ -151,13 +154,32 @@ ip_packet_match(const struct iphdr *ip,
+ return false;
+ }
+
++#undef FWINV
+ return true;
+ }
+
+ static bool
+-ip_checkentry(const struct ipt_ip *ip)
++ip_checkentry(struct ipt_ip *ip)
+ {
+- if (ip->flags & ~IPT_F_MASK) {
++#define FWINV(bool, invflg) ((bool) || (ip->invflags & (invflg)))
++
++ if (FWINV(ip->smsk.s_addr, IPT_INV_SRCIP) ||
++ FWINV(ip->dmsk.s_addr, IPT_INV_DSTIP))
++ goto has_match_rules;
++
++ if (FWINV(!!((const unsigned long *)ip->iniface_mask)[0],
++ IPT_INV_VIA_IN) ||
++ FWINV(!!((const unsigned long *)ip->outiface_mask)[0],
++ IPT_INV_VIA_OUT))
++ goto has_match_rules;
++
++ if (FWINV(ip->flags&IPT_F_FRAG, IPT_INV_FRAG))
++ goto has_match_rules;
++
++ ip->flags |= IPT_F_NO_DEF_MATCH;
++
++has_match_rules:
++ if (ip->flags & ~(IPT_F_MASK|IPT_F_NO_DEF_MATCH)) {
+ duprintf("Unknown flag bits set: %08X\n",
+ ip->flags & ~IPT_F_MASK);
+ return false;
+@@ -167,6 +189,8 @@ ip_checkentry(const struct ipt_ip *ip)
+ ip->invflags & ~IPT_INV_MASK);
+ return false;
+ }
++
++#undef FWINV
+ return true;
+ }
+
+@@ -214,7 +238,6 @@ unconditional(const struct ipt_ip *ip)
+ return 0;
+
+ return 1;
+-#undef FWINV
+ }
+
+ #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
--
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