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 struct inet_peer_base {
  69         struct inet_peer __rcu  *root;
  70         seqlock_t               lock;
  71         int                     total;
  72 };
  73
  74 extern void inet_peer_base_init(struct inet_peer_base *);
  75
  76 void                    inet_initpeers(void) __init;
  77
  78 #define INETPEER_METRICS_NEW    (~(u32) 0)
  79
  80 static inline bool inet_metrics_new(const struct inet_peer *p)
  81 {
  82         return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
  83 }
  84
  85 /* can be called with or without local BH being disabled */
  86 struct inet_peer *inet_getpeer(struct inet_peer_base *base,
  87                                const struct inetpeer_addr *daddr,
  88                                int create);
  89
  90 static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base,
  91                                                 __be32 v4daddr,
  92                                                 int create)
  93 {
  94         struct inetpeer_addr daddr;
  95
  96         daddr.addr.a4 = v4daddr;
  97         daddr.family = AF_INET;
  98         return inet_getpeer(base, &daddr, create);
  99 }
 100
 101 static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base,
 102                                                 const struct in6_addr *v6daddr,
 103                                                 int create)
 104 {
 105         struct inetpeer_addr daddr;
 106
 107         *(struct in6_addr *)daddr.addr.a6 = *v6daddr;
 108         daddr.family = AF_INET6;
 109         return inet_getpeer(base, &daddr, create);
 110 }
 111
 112 /* can be called from BH context or outside */
 113 extern void inet_putpeer(struct inet_peer *p);
 114 extern bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
 115
 116 extern void inetpeer_invalidate_tree(struct inet_peer_base *);
 117
 118 /*
 119  * temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
 120  * tcp_ts_stamp if no refcount is taken on inet_peer
 121  */
 122 static inline void inet_peer_refcheck(const struct inet_peer *p)
 123 {
 124         WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
 125 }
 126
 127
 128 /* can be called with or without local BH being disabled */
 129 static inline int inet_getid(struct inet_peer *p, int more)
 130 {
 131         int old, new;
 132         more++;
 133         inet_peer_refcheck(p);
 134         do {
 135                 old = atomic_read(&p->ip_id_count);
 136                 new = old + more;
 137                 if (!new)
 138                         new = 1;
 139         } while (atomic_cmpxchg(&p->ip_id_count, old, new) != old);
 140         return new;
 141 }
 142
 143 #endif /* _NET_INETPEER_H */