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         u32                     flush_seq;
  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 extern 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         *(struct in6_addr *)daddr.addr.a6 = *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 extern void inet_putpeer(struct inet_peer *p);
 162 extern bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
 163
 164 extern void inetpeer_invalidate_tree(struct inet_peer_base *);
 165 extern void inetpeer_invalidate_family(int family);
 166
 167 /*
 168  * temporary check to make sure we dont access rid, tcp_ts,
 169  * tcp_ts_stamp if no refcount is taken on inet_peer
 170  */
 171 static inline void inet_peer_refcheck(const struct inet_peer *p)
 172 {
 173         WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
 174 }
 175
 176 #endif /* _NET_INETPEER_H */