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ipv4: Cache dst in 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" so that all the rouitng 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@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tom Herbert 2014-01-02 11:48:26 -08:00 committed by David S. Miller
parent f916ec9608
commit 7d442fab0a
2 changed files with 92 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/net/ip_tunnels.h
View File

@ -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 */

113
net/ipv4/ip_tunnel.c
View File

@ -68,6 +68,54 @@ 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;
if (dst && (dst->flags & DST_NOCACHE))
dst = NULL;
spin_lock_bh(&t->dst_lock);
old_dst = rcu_dereference_raw(t->dst_cache);
rcu_assign_pointer(t->dst_cache, dst);
dst_release(old_dst);
spin_unlock_bh(&t->dst_lock);
}
static inline void tunnel_dst_set(struct ip_tunnel *t, struct dst_entry *dst)
{
__tunnel_dst_set(t, dst);
}
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);
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 +366,10 @@ 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 +378,6 @@ 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)
@ -350,14 +396,14 @@ 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;
tunnel_dst_set(tunnel, dst_clone(&rt->dst));
ip_rt_put(rt);
}
if (dev->type != ARPHRD_ETHER)
@ -528,10 +574,11 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
struct flowi4 fl4;
u8 tos, ttl;
__be16 df;
struct rtable *rt; /* Route to the other host */
struct rtable *rt = NULL; /* Route to the other host */
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);
@ -581,27 +628,39 @@ 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);
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);
dev->stats.collisions++;
@ -696,6 +755,7 @@ 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 +1061,9 @@ 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 +1078,8 @@ 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);