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         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
  68 void                    inet_initpeers(void) __init;
  69
  70 #define INETPEER_METRICS_NEW    (~(u32) 0)
  71
  72 static 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 */
  78 struct inet_peer        *inet_getpeer(const struct inetpeer_addr *daddr, int create);
  79
  80 static 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
  89 static 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 */
  99 extern void inet_putpeer(struct inet_peer *p);
 100 extern bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
 101
 102 extern 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  */
 108 static 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 */
 115 static 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 */