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From: Felix Fietkau <nbd@nbd.name>
Date: Fri, 16 Feb 2018 10:57:23 +0100
Subject: [PATCH] netfilter: nf_flow_table: cache mtu in struct
flow_offload_tuple
Reduces the number of cache lines touched in the offload forwarding path
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/include/net/netfilter/nf_flow_table.h
+++ b/include/net/netfilter/nf_flow_table.h
@@ -55,6 +55,8 @@ struct flow_offload_tuple {
int oifidx;
+ u16 mtu;
+
struct dst_entry *dst_cache;
};
--- a/net/ipv4/netfilter/nf_flow_table_ipv4.c
+++ b/net/ipv4/netfilter/nf_flow_table_ipv4.c
@@ -177,7 +177,7 @@ static int nf_flow_tuple_ip(struct sk_bu
}
/* Based on ip_exceeds_mtu(). */
-static bool __nf_flow_exceeds_mtu(const struct sk_buff *skb, unsigned int mtu)
+static bool nf_flow_exceeds_mtu(const struct sk_buff *skb, unsigned int mtu)
{
if (skb->len <= mtu)
return false;
@@ -191,17 +191,6 @@ static bool __nf_flow_exceeds_mtu(const
return true;
}
-static bool nf_flow_exceeds_mtu(struct sk_buff *skb, const struct rtable *rt)
-{
- u32 mtu;
-
- mtu = ip_dst_mtu_maybe_forward(&rt->dst, true);
- if (__nf_flow_exceeds_mtu(skb, mtu))
- return true;
-
- return false;
-}
-
unsigned int
nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
const struct nf_hook_state *state)
@@ -232,9 +221,9 @@ nf_flow_offload_ip_hook(void *priv, stru
dir = tuplehash->tuple.dir;
flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
-
rt = (const struct rtable *)flow->tuplehash[dir].tuple.dst_cache;
- if (unlikely(nf_flow_exceeds_mtu(skb, rt)))
+
+ if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu)))
return NF_ACCEPT;
if (skb_try_make_writable(skb, sizeof(*iph)))
--- a/net/ipv6/netfilter/nf_flow_table_ipv6.c
+++ b/net/ipv6/netfilter/nf_flow_table_ipv6.c
@@ -173,7 +173,7 @@ static int nf_flow_tuple_ipv6(struct sk_
}
/* Based on ip_exceeds_mtu(). */
-static bool __nf_flow_exceeds_mtu(const struct sk_buff *skb, unsigned int mtu)
+static bool nf_flow_exceeds_mtu(const struct sk_buff *skb, unsigned int mtu)
{
if (skb->len <= mtu)
return false;
@@ -184,17 +184,6 @@ static bool __nf_flow_exceeds_mtu(const
return true;
}
-static bool nf_flow_exceeds_mtu(struct sk_buff *skb, const struct rt6_info *rt)
-{
- u32 mtu;
-
- mtu = ip6_dst_mtu_forward(&rt->dst);
- if (__nf_flow_exceeds_mtu(skb, mtu))
- return true;
-
- return false;
-}
-
unsigned int
nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
const struct nf_hook_state *state)
@@ -225,9 +214,9 @@ nf_flow_offload_ipv6_hook(void *priv, st
dir = tuplehash->tuple.dir;
flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
-
rt = (struct rt6_info *)flow->tuplehash[dir].tuple.dst_cache;
- if (unlikely(nf_flow_exceeds_mtu(skb, rt)))
+
+ if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu)))
return NF_ACCEPT;
if (skb_try_make_writable(skb, sizeof(*ip6h)))
--- a/net/netfilter/nf_flow_table.c
+++ b/net/netfilter/nf_flow_table.c
@@ -4,6 +4,8 @@
#include <linux/netfilter.h>
#include <linux/rhashtable.h>
#include <linux/netdevice.h>
+#include <net/ip.h>
+#include <net/ip6_route.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_flow_table.h>
#include <net/netfilter/nf_conntrack.h>
@@ -23,6 +25,7 @@ flow_offload_fill_dir(struct flow_offloa
{
struct flow_offload_tuple *ft = &flow->tuplehash[dir].tuple;
struct nf_conntrack_tuple *ctt = &ct->tuplehash[dir].tuple;
+ struct dst_entry *dst = route->tuple[dir].dst;
ft->dir = dir;
@@ -30,10 +33,12 @@ flow_offload_fill_dir(struct flow_offloa
case NFPROTO_IPV4:
ft->src_v4 = ctt->src.u3.in;
ft->dst_v4 = ctt->dst.u3.in;
+ ft->mtu = ip_dst_mtu_maybe_forward(dst, true);
break;
case NFPROTO_IPV6:
ft->src_v6 = ctt->src.u3.in6;
ft->dst_v6 = ctt->dst.u3.in6;
+ ft->mtu = ip6_dst_mtu_forward(dst);
break;
}
@@ -44,8 +49,7 @@ flow_offload_fill_dir(struct flow_offloa
ft->iifidx = route->tuple[dir].ifindex;
ft->oifidx = route->tuple[!dir].ifindex;
-
- ft->dst_cache = route->tuple[dir].dst;
+ ft->dst_cache = dst;
}
struct flow_offload *
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