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Date: Wed, 11 Dec 2013 22:17:29 -0800 (PST)
From: Tom Herbert <therbert@...gle.com>
To: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH] net: Cache route in IP tunnels
Avoid doing a route lookup on every packet being tunneled.
In ip_tunnel.c cache the route returned from ip_route_output if
the tunnel is "connected", that is all the routing parameters are
taken from tunnel parms for a packet. Specifically, not NBMA tunnel
and tos is from tunnel parms (not inner packet).
Signed-off-by: Tom Herbert <therbert@...gle.com>
---
include/net/ip_tunnels.h | 3 ++
net/ipv4/ip_tunnel.c | 106 +++++++++++++++++++++++++++++++++++++----------
2 files changed, 86 insertions(+), 23 deletions(-)
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 732f8c6..bde50fc 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -54,6 +54,9 @@ struct ip_tunnel {
int hlen; /* Precalculated header length */
int mlink;
+ struct dst_entry __rcu *dst_cache;
+ spinlock_t dst_lock;
+
struct ip_tunnel_parm parms;
/* for SIT */
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 90ff957..c4db0cc 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -68,6 +68,50 @@ static unsigned int ip_tunnel_hash(struct ip_tunnel_net *itn,
IP_TNL_HASH_BITS);
}
+static inline void
+tunnel_dst_set(struct ip_tunnel *t, struct dst_entry *dst)
+{
+ struct dst_entry *old_dst;
+
+ spin_lock(&t->dst_lock);
+ old_dst = rcu_dereference_raw(t->dst_cache);
+ rcu_assign_pointer(t->dst_cache, dst);
+ dst_release(old_dst);
+ spin_unlock(&t->dst_lock);
+}
+
+static inline void
+tunnel_dst_reset(struct ip_tunnel *t)
+{
+ tunnel_dst_set(t, NULL);
+}
+
+static inline struct dst_entry *
+tunnel_dst_get(struct ip_tunnel *t)
+{
+ struct dst_entry *dst;
+
+ rcu_read_lock();
+ dst = rcu_dereference(t->dst_cache);
+ if (dst)
+ dst_hold(dst);
+ rcu_read_unlock();
+ return dst;
+}
+
+struct dst_entry *tunnel_dst_check(struct ip_tunnel *t, u32 cookie)
+{
+ struct dst_entry *dst = tunnel_dst_get(t);
+
+ if (dst && dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
+ tunnel_dst_reset(t);
+ dst_release(dst);
+ return NULL;
+ }
+
+ return dst;
+}
+
/* Often modified stats are per cpu, other are shared (netdev->stats) */
struct rtnl_link_stats64 *ip_tunnel_get_stats64(struct net_device *dev,
struct rtnl_link_stats64 *tot)
@@ -318,11 +362,9 @@ failed:
return ERR_PTR(err);
}
-static inline struct rtable *ip_route_output_tunnel(struct net *net,
- struct flowi4 *fl4,
- int proto,
- __be32 daddr, __be32 saddr,
- __be32 key, __u8 tos, int oif)
+static inline void init_tunnel_flow(struct flowi4 *fl4, int proto,
+ __be32 daddr, __be32 saddr,
+ __be32 key, __u8 tos, int oif)
{
memset(fl4, 0, sizeof(*fl4));
fl4->flowi4_oif = oif;
@@ -331,7 +373,6 @@ static inline struct rtable *ip_route_output_tunnel(struct net *net,
fl4->flowi4_tos = tos;
fl4->flowi4_proto = proto;
fl4->fl4_gre_key = key;
- return ip_route_output_key(net, fl4);
}
static int ip_tunnel_bind_dev(struct net_device *dev)
@@ -350,12 +391,11 @@ static int ip_tunnel_bind_dev(struct net_device *dev)
struct flowi4 fl4;
struct rtable *rt;
- rt = ip_route_output_tunnel(tunnel->net, &fl4,
- tunnel->parms.iph.protocol,
- iph->daddr, iph->saddr,
- tunnel->parms.o_key,
- RT_TOS(iph->tos),
- tunnel->parms.link);
+ init_tunnel_flow(&fl4, iph->protocol, iph->daddr,
+ iph->saddr, tunnel->parms.o_key,
+ RT_TOS(iph->tos), tunnel->parms.link);
+ rt = ip_route_output_key(tunnel->net, &fl4);
+
if (!IS_ERR(rt)) {
tdev = rt->dst.dev;
ip_rt_put(rt);
@@ -532,6 +572,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
unsigned int max_headroom; /* The extra header space needed */
__be32 dst;
int err;
+ bool connected = true;
inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
@@ -581,26 +622,39 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
#endif
else
goto tx_error;
+
+ connected = false;
}
tos = tnl_params->tos;
if (tos & 0x1) {
tos &= ~0x1;
- if (skb->protocol == htons(ETH_P_IP))
+ if (skb->protocol == htons(ETH_P_IP)) {
tos = inner_iph->tos;
- else if (skb->protocol == htons(ETH_P_IPV6))
+ connected = false;
+ } else if (skb->protocol == htons(ETH_P_IPV6)) {
tos = ipv6_get_dsfield((const struct ipv6hdr *)inner_iph);
+ connected = false;
+ }
}
- rt = ip_route_output_tunnel(tunnel->net, &fl4,
- protocol,
- dst, tnl_params->saddr,
- tunnel->parms.o_key,
- RT_TOS(tos),
- tunnel->parms.link);
- if (IS_ERR(rt)) {
- dev->stats.tx_carrier_errors++;
- goto tx_error;
+ init_tunnel_flow(&fl4, protocol, dst, tnl_params->saddr,
+ tunnel->parms.o_key, RT_TOS(tos), tunnel->parms.link);
+
+ if (connected)
+ rt = (struct rtable *)tunnel_dst_check(tunnel, 0);
+ else
+ rt = NULL;
+
+ if (!rt) {
+ rt = ip_route_output_key(tunnel->net, &fl4);
+
+ if (IS_ERR(rt)) {
+ dev->stats.tx_carrier_errors++;
+ goto tx_error;
+ }
+ if (connected)
+ tunnel_dst_set(tunnel, dst_clone(&rt->dst));
}
if (rt->dst.dev == dev) {
ip_rt_put(rt);
@@ -696,6 +750,7 @@ static void ip_tunnel_update(struct ip_tunnel_net *itn,
if (set_mtu)
dev->mtu = mtu;
}
+ tunnel_dst_reset(t);
netdev_state_change(dev);
}
@@ -1001,6 +1056,9 @@ int ip_tunnel_init(struct net_device *dev)
iph->version = 4;
iph->ihl = 5;
+ tunnel->dst_cache = NULL;
+ spin_lock_init(&tunnel->dst_lock);
+
return 0;
}
EXPORT_SYMBOL_GPL(ip_tunnel_init);
@@ -1015,6 +1073,8 @@ void ip_tunnel_uninit(struct net_device *dev)
/* fb_tunnel_dev will be unregisted in net-exit call. */
if (itn->fb_tunnel_dev != dev)
ip_tunnel_del(netdev_priv(dev));
+
+ tunnel_dst_reset(tunnel);
}
EXPORT_SYMBOL_GPL(ip_tunnel_uninit);
--
1.8.5.1
--
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