linux/include/net/ip6_route.h
Eric Dumazet b6c6712a42 net: sk_dst_cache RCUification
With latest CONFIG_PROVE_RCU stuff, I felt more comfortable to make this
work.

sk->sk_dst_cache is currently protected by a rwlock (sk_dst_lock)

This rwlock is readlocked for a very small amount of time, and dst
entries are already freed after RCU grace period. This calls for RCU
again :)

This patch converts sk_dst_lock to a spinlock, and use RCU for readers.

__sk_dst_get() is supposed to be called with rcu_read_lock() or if
socket locked by user, so use appropriate rcu_dereference_check()
condition (rcu_read_lock_held() || sock_owned_by_user(sk))

This patch avoids two atomic ops per tx packet on UDP connected sockets,
for example, and permits sk_dst_lock to be much less dirtied.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-13 01:41:33 -07:00

169 lines
4.3 KiB
C

#ifndef _NET_IP6_ROUTE_H
#define _NET_IP6_ROUTE_H
#define IP6_RT_PRIO_USER 1024
#define IP6_RT_PRIO_ADDRCONF 256
#define IP6_RT_PRIO_KERN 512
struct route_info {
__u8 type;
__u8 length;
__u8 prefix_len;
#if defined(__BIG_ENDIAN_BITFIELD)
__u8 reserved_h:3,
route_pref:2,
reserved_l:3;
#elif defined(__LITTLE_ENDIAN_BITFIELD)
__u8 reserved_l:3,
route_pref:2,
reserved_h:3;
#endif
__be32 lifetime;
__u8 prefix[0]; /* 0,8 or 16 */
};
#ifdef __KERNEL__
#include <net/flow.h>
#include <net/ip6_fib.h>
#include <net/sock.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#define RT6_LOOKUP_F_IFACE 0x00000001
#define RT6_LOOKUP_F_REACHABLE 0x00000002
#define RT6_LOOKUP_F_HAS_SADDR 0x00000004
#define RT6_LOOKUP_F_SRCPREF_TMP 0x00000008
#define RT6_LOOKUP_F_SRCPREF_PUBLIC 0x00000010
#define RT6_LOOKUP_F_SRCPREF_COA 0x00000020
/*
* rt6_srcprefs2flags() and rt6_flags2srcprefs() translate
* between IPV6_ADDR_PREFERENCES socket option values
* IPV6_PREFER_SRC_TMP = 0x1
* IPV6_PREFER_SRC_PUBLIC = 0x2
* IPV6_PREFER_SRC_COA = 0x4
* and above RT6_LOOKUP_F_SRCPREF_xxx flags.
*/
static inline int rt6_srcprefs2flags(unsigned int srcprefs)
{
/* No need to bitmask because srcprefs have only 3 bits. */
return srcprefs << 3;
}
static inline unsigned int rt6_flags2srcprefs(int flags)
{
return (flags >> 3) & 7;
}
extern void ip6_route_input(struct sk_buff *skb);
extern struct dst_entry * ip6_route_output(struct net *net,
struct sock *sk,
struct flowi *fl);
extern int ip6_route_init(void);
extern void ip6_route_cleanup(void);
extern int ipv6_route_ioctl(struct net *net,
unsigned int cmd,
void __user *arg);
extern int ip6_route_add(struct fib6_config *cfg);
extern int ip6_ins_rt(struct rt6_info *);
extern int ip6_del_rt(struct rt6_info *);
extern struct rt6_info *rt6_lookup(struct net *net,
const struct in6_addr *daddr,
const struct in6_addr *saddr,
int oif, int flags);
extern struct dst_entry *icmp6_dst_alloc(struct net_device *dev,
struct neighbour *neigh,
const struct in6_addr *addr);
extern int icmp6_dst_gc(void);
extern void fib6_force_start_gc(struct net *net);
extern struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev,
const struct in6_addr *addr,
int anycast);
extern int ip6_dst_hoplimit(struct dst_entry *dst);
/*
* support functions for ND
*
*/
extern struct rt6_info * rt6_get_dflt_router(struct in6_addr *addr,
struct net_device *dev);
extern struct rt6_info * rt6_add_dflt_router(struct in6_addr *gwaddr,
struct net_device *dev,
unsigned int pref);
extern void rt6_purge_dflt_routers(struct net *net);
extern int rt6_route_rcv(struct net_device *dev,
u8 *opt, int len,
struct in6_addr *gwaddr);
extern void rt6_redirect(struct in6_addr *dest,
struct in6_addr *src,
struct in6_addr *saddr,
struct neighbour *neigh,
u8 *lladdr,
int on_link);
extern void rt6_pmtu_discovery(struct in6_addr *daddr,
struct in6_addr *saddr,
struct net_device *dev,
u32 pmtu);
struct netlink_callback;
struct rt6_rtnl_dump_arg {
struct sk_buff *skb;
struct netlink_callback *cb;
struct net *net;
};
extern int rt6_dump_route(struct rt6_info *rt, void *p_arg);
extern void rt6_ifdown(struct net *net, struct net_device *dev);
extern void rt6_mtu_change(struct net_device *dev, unsigned mtu);
/*
* Store a destination cache entry in a socket
*/
static inline void __ip6_dst_store(struct sock *sk, struct dst_entry *dst,
struct in6_addr *daddr, struct in6_addr *saddr)
{
struct ipv6_pinfo *np = inet6_sk(sk);
struct rt6_info *rt = (struct rt6_info *) dst;
sk_setup_caps(sk, dst);
np->daddr_cache = daddr;
#ifdef CONFIG_IPV6_SUBTREES
np->saddr_cache = saddr;
#endif
np->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
}
static inline void ip6_dst_store(struct sock *sk, struct dst_entry *dst,
struct in6_addr *daddr, struct in6_addr *saddr)
{
spin_lock(&sk->sk_dst_lock);
__ip6_dst_store(sk, dst, daddr, saddr);
spin_unlock(&sk->sk_dst_lock);
}
static inline int ipv6_unicast_destination(struct sk_buff *skb)
{
struct rt6_info *rt = (struct rt6_info *) skb_dst(skb);
return rt->rt6i_flags & RTF_LOCAL;
}
#endif
#endif