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                 struct in6_addr         in6;
  23         };
  24 };
  25
  26 struct inetpeer_addr {
  27         struct inetpeer_addr_base       addr;
  28         __u16                           family;
  29 };
  30
  31 struct inet_peer {
  32         /* group together avl_left,avl_right,v4daddr to speedup lookups */
  33         struct inet_peer __rcu  *avl_left, *avl_right;
  34         struct inetpeer_addr    daddr;
  35         __u32                   avl_height;
  36
  37         u32                     metrics[RTAX_MAX];
  38         u32                     rate_tokens;    /* rate limiting for ICMP */
  39         unsigned long           rate_last;
  40         union {
  41                 struct list_head        gc_list;
  42                 struct rcu_head     gc_rcu;
  43         };
  44         /*
  45          * Once inet_peer is queued for deletion (refcnt == -1), following field
  46          * is not available: rid
  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                 };
  53                 struct rcu_head         rcu;
  54                 struct inet_peer        *gc_next;
  55         };
  56
  57         /* following fields might be frequently dirtied */
  58         __u32                   dtime;  /* the time of last use of not referenced entries */
  59         atomic_t                refcnt;
  60 };
  61
  62 struct inet_peer_base {
  63         struct inet_peer __rcu  *root;
  64         seqlock_t               lock;
  65         int                     total;
  66 };
  67
  68 #define INETPEER_BASE_BIT       0x1UL
  69
  70 static inline struct inet_peer *inetpeer_ptr(unsigned long val)
  71 {
  72         BUG_ON(val & INETPEER_BASE_BIT);
  73         return (struct inet_peer *) val;
  74 }
  75
  76 static inline struct inet_peer_base *inetpeer_base_ptr(unsigned long val)
  77 {
  78         if (!(val & INETPEER_BASE_BIT))
  79                 return NULL;
  80         val &= ~INETPEER_BASE_BIT;
  81         return (struct inet_peer_base *) val;
  82 }
  83
  84 static inline bool inetpeer_ptr_is_peer(unsigned long val)
  85 {
  86         return !(val & INETPEER_BASE_BIT);
  87 }
  88
  89 static inline void __inetpeer_ptr_set_peer(unsigned long *val, struct inet_peer *peer)
  90 {
  91         /* This implicitly clears INETPEER_BASE_BIT */
  92         *val = (unsigned long) peer;
  93 }
  94
  95 static inline bool inetpeer_ptr_set_peer(unsigned long *ptr, struct inet_peer *peer)
  96 {
  97         unsigned long val = (unsigned long) peer;
  98         unsigned long orig = *ptr;
  99
 100         if (!(orig & INETPEER_BASE_BIT) ||
 101             cmpxchg(ptr, orig, val) != orig)
 102                 return false;
 103         return true;
 104 }
 105
 106 static inline void inetpeer_init_ptr(unsigned long *ptr, struct inet_peer_base *base)
 107 {
 108         *ptr = (unsigned long) base | INETPEER_BASE_BIT;
 109 }
 110
 111 static inline void inetpeer_transfer_peer(unsigned long *to, unsigned long *from)
 112 {
 113         unsigned long val = *from;
 114
 115         *to = val;
 116         if (inetpeer_ptr_is_peer(val)) {
 117                 struct inet_peer *peer = inetpeer_ptr(val);
 118                 atomic_inc(&peer->refcnt);
 119         }
 120 }
 121
 122 void inet_peer_base_init(struct inet_peer_base *);
 123
 124 void inet_initpeers(void) __init;
 125
 126 #define INETPEER_METRICS_NEW    (~(u32) 0)
 127
 128 static inline bool inet_metrics_new(const struct inet_peer *p)
 129 {
 130         return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
 131 }
 132
 133 /* can be called with or without local BH being disabled */
 134 struct inet_peer *inet_getpeer(struct inet_peer_base *base,
 135                                const struct inetpeer_addr *daddr,
 136                                int create);
 137
 138 static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base,
 139                                                 __be32 v4daddr,
 140                                                 int create)
 141 {
 142         struct inetpeer_addr daddr;
 143
 144         daddr.addr.a4 = v4daddr;
 145         daddr.family = AF_INET;
 146         return inet_getpeer(base, &daddr, create);
 147 }
 148
 149 static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base,
 150                                                 const struct in6_addr *v6daddr,
 151                                                 int create)
 152 {
 153         struct inetpeer_addr daddr;
 154
 155         daddr.addr.in6 = *v6daddr;
 156         daddr.family = AF_INET6;
 157         return inet_getpeer(base, &daddr, create);
 158 }
 159
 160 /* can be called from BH context or outside */
 161 void inet_putpeer(struct inet_peer *p);
 162 bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
 163
 164 void inetpeer_invalidate_tree(struct inet_peer_base *);
 165
 166 /*
 167  * temporary check to make sure we dont access rid, tcp_ts,
 168  * tcp_ts_stamp if no refcount is taken on inet_peer
 169  */
 170 static inline void inet_peer_refcheck(const struct inet_peer *p)
 171 {
 172         WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
 173 }
 174 #endif /* _NET_INETPEER_H */