/*
* INETPEER - A storage for permanent information about peers
*
* Authors: Andrey V. Savochkin <[email protected]>
*/

#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;
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
* 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 */
};
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;
u32 flush_seq;
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) ||
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);
}
}

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 */
void inet_putpeer(struct inet_peer *p);
bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);

void inetpeer_invalidate_tree(struct inet_peer_base *);
void inetpeer_invalidate_family(int family);

/*
* 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 */