LXR linux/include/net/inetpeer.h

   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 <linux/rtnetlink.h>
  15#include <net/ipv6.h>
  16#include <linux/atomic.h>
  17
  18struct inetpeer_addr_base {
  19        union {
  20                __be32                  a4;
  21                __be32                  a6[4];
  22        };
  23};
  24
  25struct inetpeer_addr {
  26        struct inetpeer_addr_base       addr;
  27        __u16                           family;
  28};
  29
  30struct inet_peer {
  31        /* group together avl_left,avl_right,v4daddr to speedup lookups */
  32        struct inet_peer __rcu  *avl_left, *avl_right;
  33        struct inetpeer_addr    daddr;
  34        __u32                   avl_height;
  35
  36        u32                     metrics[RTAX_MAX];
  37        u32                     rate_tokens;    /* rate limiting for ICMP */
  38        unsigned long           rate_last;
  39        unsigned long           pmtu_expires;
  40        u32                     pmtu_orig;
  41        u32                     pmtu_learned;
  42        struct inetpeer_addr_base redirect_learned;
  43        union {
  44                struct list_head        gc_list;
  45                struct rcu_head     gc_rcu;
  46        };
  47        /*
  48         * Once inet_peer is queued for deletion (refcnt == -1), following fields
  49         * are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp
  50         * We can share memory with rcu_head to help keep inet_peer small.
  51         */
  52        union {
  53                struct {
  54                        atomic_t                        rid;            /* Frag reception counter */
  55                        atomic_t                        ip_id_count;    /* IP ID for the next packet */
  56                        __u32                           tcp_ts;
  57                        __u32                           tcp_ts_stamp;
  58                };
  59                struct rcu_head         rcu;
  60                struct inet_peer        *gc_next;
  61        };
  62
  63        /* following fields might be frequently dirtied */
  64        __u32                   dtime;  /* the time of last use of not referenced entries */
  65        atomic_t                refcnt;
  66};
  67
  68void                    inet_initpeers(void) __init;
  69
  70#define INETPEER_METRICS_NEW    (~(u32) 0)
  71
  72static inline bool inet_metrics_new(const struct inet_peer *p)
  73{
  74        return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
  75}
  76
  77/* can be called with or without local BH being disabled */
  78struct inet_peer        *inet_getpeer(const struct inetpeer_addr *daddr, int create);
  79
  80static inline struct inet_peer *inet_getpeer_v4(__be32 v4daddr, int create)
  81{
  82        struct inetpeer_addr daddr;
  83
  84        daddr.addr.a4 = v4daddr;
  85        daddr.family = AF_INET;
  86        return inet_getpeer(&daddr, create);
  87}
  88
  89static inline struct inet_peer *inet_getpeer_v6(const struct in6_addr *v6daddr, int create)
  90{
  91        struct inetpeer_addr daddr;
  92
  93        *(struct in6_addr *)daddr.addr.a6 = *v6daddr;
  94        daddr.family = AF_INET6;
  95        return inet_getpeer(&daddr, create);
  96}
  97
  98/* can be called from BH context or outside */
  99extern void inet_putpeer(struct inet_peer *p);
 100extern bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
 101
 102extern void inetpeer_invalidate_tree(int family);
 103
 104/*
 105 * temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
 106 * tcp_ts_stamp if no refcount is taken on inet_peer
 107 */
 108static inline void inet_peer_refcheck(const struct inet_peer *p)
 109{
 110        WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
 111}
 112
 113
 114/* can be called with or without local BH being disabled */
 115static inline int inet_getid(struct inet_peer *p, int more)
 116{
 117        int old, new;
 118        more++;
 119        inet_peer_refcheck(p);
 120        do {
 121                old = atomic_read(&p->ip_id_count);
 122                new = old + more;
 123                if (!new)
 124                        new = 1;
 125        } while (atomic_cmpxchg(&p->ip_id_count, old, new) != old);
 126        return new;
 127}
 128
 129#endif /* _NET_INETPEER_H */
 130