1/* 2 * INETPEER - A storage for permanent information about peers 3 * 4 * Authors: Andrey V. Savochkin <saw@msu.ru> 5 */ 6 7#ifndef _NET_INETPEER_H 8#define _NET_INETPEER_H 9 10#include <linux/types.h> 11#include <linux/init.h> 12#include <linux/jiffies.h> 13#include <linux/spinlock.h> 14#include <asm/atomic.h> 15 16struct inet_peer { 17 /* group together avl_left,avl_right,v4daddr to speedup lookups */ 18 struct inet_peer *avl_left, *avl_right; 19 __be32 v4daddr; /* peer's address */ 20 __u32 avl_height; 21 struct list_head unused; 22 __u32 dtime; /* the time of last use of not 23 * referenced entries */ 24 atomic_t refcnt; 25 /* 26 * Once inet_peer is queued for deletion (refcnt == -1), following fields 27 * are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp 28 * We can share memory with rcu_head to keep inet_peer small 29 * (less then 64 bytes) 30 */ 31 union { 32 struct { 33 atomic_t rid; /* Frag reception counter */ 34 atomic_t ip_id_count; /* IP ID for the next packet */ 35 __u32 tcp_ts; 36 __u32 tcp_ts_stamp; 37 }; 38 struct rcu_head rcu; 39 }; 40}; 41 42void inet_initpeers(void) __init; 43 44/* can be called with or without local BH being disabled */ 45struct inet_peer *inet_getpeer(__be32 daddr, int create); 46 47/* can be called from BH context or outside */ 48extern void inet_putpeer(struct inet_peer *p); 49 50/* 51 * temporary check to make sure we dont access rid, ip_id_count, tcp_ts, 52 * tcp_ts_stamp if no refcount is taken on inet_peer 53 */ 54static inline void inet_peer_refcheck(const struct inet_peer *p) 55{ 56 WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0); 57} 58 59 60/* can be called with or without local BH being disabled */ 61static inline __u16 inet_getid(struct inet_peer *p, int more) 62{ 63 more++; 64 inet_peer_refcheck(p); 65 return atomic_add_return(more, &p->ip_id_count) - more; 66} 67 68#endif /* _NET_INETPEER_H */ 69