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