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         union {
  40                 struct list_head        gc_list;
  41                 struct rcu_head     gc_rcu;
  42         };
  43         /*
  44          * Once inet_peer is queued for deletion (refcnt == -1), following field
  45          * is not available: rid
  46          * We can share memory with rcu_head to help keep inet_peer small.
  47          */
  48         union {
  49                 struct {
  50                         atomic_t                        rid;            /* Frag reception counter */
  51                 };
  52                 struct rcu_head         rcu;
  53                 struct inet_peer        *gc_next;
  54         };
  55
  56         /* following fields might be frequently dirtied */
  57         __u32                   dtime;  /* the time of last use of not referenced entries */
  58         atomic_t                refcnt;
  59 };
  60
  61 struct inet_peer_base {
  62         struct inet_peer __rcu  *root;
  63         seqlock_t               lock;
  64         int                     total;
  65 };
  66
  67 #define INETPEER_BASE_BIT       0x1UL
  68
  69 static inline struct inet_peer *inetpeer_ptr(unsigned long val)
  70 {
  71         BUG_ON(val & INETPEER_BASE_BIT);
  72         return (struct inet_peer *) val;
  73 }
  74
  75 static inline struct inet_peer_base *inetpeer_base_ptr(unsigned long val)
  76 {
  77         if (!(val & INETPEER_BASE_BIT))
  78                 return NULL;
  79         val &= ~INETPEER_BASE_BIT;
  80         return (struct inet_peer_base *) val;
  81 }
  82
  83 static inline bool inetpeer_ptr_is_peer(unsigned long val)
  84 {
  85         return !(val & INETPEER_BASE_BIT);
  86 }
  87
  88 static inline void __inetpeer_ptr_set_peer(unsigned long *val, struct inet_peer *peer)
  89 {
  90         /* This implicitly clears INETPEER_BASE_BIT */
  91         *val = (unsigned long) peer;
  92 }
  93
  94 static inline bool inetpeer_ptr_set_peer(unsigned long *ptr, struct inet_peer *peer)
  95 {
  96         unsigned long val = (unsigned long) peer;
  97         unsigned long orig = *ptr;
  98
  99         if (!(orig & INETPEER_BASE_BIT) ||
 100             cmpxchg(ptr, orig, val) != orig)
 101                 return false;
 102         return true;
 103 }
 104
 105 static inline void inetpeer_init_ptr(unsigned long *ptr, struct inet_peer_base *base)
 106 {
 107         *ptr = (unsigned long) base | INETPEER_BASE_BIT;
 108 }
 109
 110 static inline void inetpeer_transfer_peer(unsigned long *to, unsigned long *from)
 111 {
 112         unsigned long val = *from;
 113
 114         *to = val;
 115         if (inetpeer_ptr_is_peer(val)) {
 116                 struct inet_peer *peer = inetpeer_ptr(val);
 117                 atomic_inc(&peer->refcnt);
 118         }
 119 }
 120
 121 void inet_peer_base_init(struct inet_peer_base *);
 122
 123 void inet_initpeers(void) __init;
 124
 125 #define INETPEER_METRICS_NEW    (~(u32) 0)
 126
 127 static inline bool inet_metrics_new(const struct inet_peer *p)
 128 {
 129         return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
 130 }
 131
 132 /* can be called with or without local BH being disabled */
 133 struct inet_peer *inet_getpeer(struct inet_peer_base *base,
 134                                const struct inetpeer_addr *daddr,
 135                                int create);
 136
 137 static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base,
 138                                                 __be32 v4daddr,
 139                                                 int create)
 140 {
 141         struct inetpeer_addr daddr;
 142
 143         daddr.addr.a4 = v4daddr;
 144         daddr.family = AF_INET;
 145         return inet_getpeer(base, &daddr, create);
 146 }
 147
 148 static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base,
 149                                                 const struct in6_addr *v6daddr,
 150                                                 int create)
 151 {
 152         struct inetpeer_addr daddr;
 153
 154         *(struct in6_addr *)daddr.addr.a6 = *v6daddr;
 155         daddr.family = AF_INET6;
 156         return inet_getpeer(base, &daddr, create);
 157 }
 158
 159 /* can be called from BH context or outside */
 160 void inet_putpeer(struct inet_peer *p);
 161 bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
 162
 163 void inetpeer_invalidate_tree(struct inet_peer_base *);
 164
 165 /*
 166  * temporary check to make sure we dont access rid, tcp_ts,
 167  * tcp_ts_stamp if no refcount is taken on inet_peer
 168  */
 169 static inline void inet_peer_refcheck(const struct inet_peer *p)
 170 {
 171         WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
 172 }
 173 #endif /* _NET_INETPEER_H */