linux-stable/include/net/inetpeer.h
David S. Miller 97bab73f98 inet: Hide route peer accesses behind helpers.
We encode the pointer(s) into an unsigned long with one state bit.

The state bit is used so we can store the inetpeer tree root to use
when resolving the peer later.

Later the peer roots will be per-FIB table, and this change works to
facilitate that.

Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-11 02:08:47 -07:00

197 lines
4.7 KiB
C

/*
* INETPEER - A storage for permanent information about peers
*
* Authors: Andrey V. Savochkin <saw@msu.ru>
*/
#ifndef _NET_INETPEER_H
#define _NET_INETPEER_H
#include <linux/types.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/spinlock.h>
#include <linux/rtnetlink.h>
#include <net/ipv6.h>
#include <linux/atomic.h>
struct inetpeer_addr_base {
union {
__be32 a4;
__be32 a6[4];
};
};
struct inetpeer_addr {
struct inetpeer_addr_base addr;
__u16 family;
};
struct inet_peer {
/* group together avl_left,avl_right,v4daddr to speedup lookups */
struct inet_peer __rcu *avl_left, *avl_right;
struct inetpeer_addr daddr;
__u32 avl_height;
u32 metrics[RTAX_MAX];
u32 rate_tokens; /* rate limiting for ICMP */
unsigned long rate_last;
unsigned long pmtu_expires;
u32 pmtu_orig;
u32 pmtu_learned;
struct inetpeer_addr_base redirect_learned;
union {
struct list_head gc_list;
struct rcu_head gc_rcu;
};
/*
* Once inet_peer is queued for deletion (refcnt == -1), following fields
* are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp
* We can share memory with rcu_head to help keep inet_peer small.
*/
union {
struct {
atomic_t rid; /* Frag reception counter */
atomic_t ip_id_count; /* IP ID for the next packet */
__u32 tcp_ts;
__u32 tcp_ts_stamp;
};
struct rcu_head rcu;
struct inet_peer *gc_next;
};
/* following fields might be frequently dirtied */
__u32 dtime; /* the time of last use of not referenced entries */
atomic_t refcnt;
};
struct inet_peer_base {
struct inet_peer __rcu *root;
seqlock_t lock;
int total;
};
#define INETPEER_BASE_BIT 0x1UL
static inline struct inet_peer *inetpeer_ptr(unsigned long val)
{
BUG_ON(val & INETPEER_BASE_BIT);
return (struct inet_peer *) val;
}
static inline struct inet_peer_base *inetpeer_base_ptr(unsigned long val)
{
if (!(val & INETPEER_BASE_BIT))
return NULL;
val &= ~INETPEER_BASE_BIT;
return (struct inet_peer_base *) val;
}
static inline bool inetpeer_ptr_is_peer(unsigned long val)
{
return !(val & INETPEER_BASE_BIT);
}
static inline void __inetpeer_ptr_set_peer(unsigned long *val, struct inet_peer *peer)
{
/* This implicitly clears INETPEER_BASE_BIT */
*val = (unsigned long) peer;
}
static inline bool inetpeer_ptr_set_peer(unsigned long *ptr, struct inet_peer *peer)
{
unsigned long val = (unsigned long) peer;
unsigned long orig = *ptr;
if (!(orig & INETPEER_BASE_BIT) || !val ||
cmpxchg(ptr, orig, val) != orig)
return false;
return true;
}
static inline void inetpeer_init_ptr(unsigned long *ptr, struct inet_peer_base *base)
{
*ptr = (unsigned long) base | INETPEER_BASE_BIT;
}
static inline void inetpeer_transfer_peer(unsigned long *to, unsigned long *from)
{
unsigned long val = *from;
*to = val;
if (inetpeer_ptr_is_peer(val)) {
struct inet_peer *peer = inetpeer_ptr(val);
atomic_inc(&peer->refcnt);
}
}
extern void inet_peer_base_init(struct inet_peer_base *);
void inet_initpeers(void) __init;
#define INETPEER_METRICS_NEW (~(u32) 0)
static inline bool inet_metrics_new(const struct inet_peer *p)
{
return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
}
/* can be called with or without local BH being disabled */
struct inet_peer *inet_getpeer(struct inet_peer_base *base,
const struct inetpeer_addr *daddr,
int create);
static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base,
__be32 v4daddr,
int create)
{
struct inetpeer_addr daddr;
daddr.addr.a4 = v4daddr;
daddr.family = AF_INET;
return inet_getpeer(base, &daddr, create);
}
static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base,
const struct in6_addr *v6daddr,
int create)
{
struct inetpeer_addr daddr;
*(struct in6_addr *)daddr.addr.a6 = *v6daddr;
daddr.family = AF_INET6;
return inet_getpeer(base, &daddr, create);
}
/* can be called from BH context or outside */
extern void inet_putpeer(struct inet_peer *p);
extern bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
extern void inetpeer_invalidate_tree(struct inet_peer_base *);
/*
* temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
* tcp_ts_stamp if no refcount is taken on inet_peer
*/
static inline void inet_peer_refcheck(const struct inet_peer *p)
{
WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
}
/* can be called with or without local BH being disabled */
static inline int inet_getid(struct inet_peer *p, int more)
{
int old, new;
more++;
inet_peer_refcheck(p);
do {
old = atomic_read(&p->ip_id_count);
new = old + more;
if (!new)
new = 1;
} while (atomic_cmpxchg(&p->ip_id_count, old, new) != old);
return new;
}
#endif /* _NET_INETPEER_H */