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 fields
  45          * are not available: rid, ip_id_count
  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                         atomic_t                        ip_id_count;    /* IP ID for the next packet */
  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         u32                     flush_seq;
  66         int                     total;
  67 };
  68
  69 #define INETPEER_BASE_BIT       0x1UL
  70
  71 static inline struct inet_peer *inetpeer_ptr(unsigned long val)
  72 {
  73         BUG_ON(val & INETPEER_BASE_BIT);
  74         return (struct inet_peer *) val;
  75 }
  76
  77 static inline struct inet_peer_base *inetpeer_base_ptr(unsigned long val)
  78 {
  79         if (!(val & INETPEER_BASE_BIT))
  80                 return NULL;
  81         val &= ~INETPEER_BASE_BIT;
  82         return (struct inet_peer_base *) val;
  83 }
  84
  85 static inline bool inetpeer_ptr_is_peer(unsigned long val)
  86 {
  87         return !(val & INETPEER_BASE_BIT);
  88 }
  89
  90 static inline void __inetpeer_ptr_set_peer(unsigned long *val, struct inet_peer *peer)
  91 {
  92         /* This implicitly clears INETPEER_BASE_BIT */
  93         *val = (unsigned long) peer;
  94 }
  95
  96 static inline bool inetpeer_ptr_set_peer(unsigned long *ptr, struct inet_peer *peer)
  97 {
  98         unsigned long val = (unsigned long) peer;
  99         unsigned long orig = *ptr;
 100
 101         if (!(orig & INETPEER_BASE_BIT) ||
 102             cmpxchg(ptr, orig, val) != orig)
 103                 return false;
 104         return true;
 105 }
 106
 107 static inline void inetpeer_init_ptr(unsigned long *ptr, struct inet_peer_base *base)
 108 {
 109         *ptr = (unsigned long) base | INETPEER_BASE_BIT;
 110 }
 111
 112 static inline void inetpeer_transfer_peer(unsigned long *to, unsigned long *from)
 113 {
 114         unsigned long val = *from;
 115
 116         *to = val;
 117         if (inetpeer_ptr_is_peer(val)) {
 118                 struct inet_peer *peer = inetpeer_ptr(val);
 119                 atomic_inc(&peer->refcnt);
 120         }
 121 }
 122
 123 void inet_peer_base_init(struct inet_peer_base *);
 124
 125 void inet_initpeers(void) __init;
 126
 127 #define INETPEER_METRICS_NEW    (~(u32) 0)
 128
 129 static inline bool inet_metrics_new(const struct inet_peer *p)
 130 {
 131         return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
 132 }
 133
 134 /* can be called with or without local BH being disabled */
 135 struct inet_peer *inet_getpeer(struct inet_peer_base *base,
 136                                const struct inetpeer_addr *daddr,
 137                                int create);
 138
 139 static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base,
 140                                                 __be32 v4daddr,
 141                                                 int create)
 142 {
 143         struct inetpeer_addr daddr;
 144
 145         daddr.addr.a4 = v4daddr;
 146         daddr.family = AF_INET;
 147         return inet_getpeer(base, &daddr, create);
 148 }
 149
 150 static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base,
 151                                                 const struct in6_addr *v6daddr,
 152                                                 int create)
 153 {
 154         struct inetpeer_addr daddr;
 155
 156         *(struct in6_addr *)daddr.addr.a6 = *v6daddr;
 157         daddr.family = AF_INET6;
 158         return inet_getpeer(base, &daddr, create);
 159 }
 160
 161 /* can be called from BH context or outside */
 162 void inet_putpeer(struct inet_peer *p);
 163 bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
 164
 165 void inetpeer_invalidate_tree(struct inet_peer_base *);
 166
 167 /*
 168  * temporary check to make sure we dont access rid, ip_id_count, 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
 177 /* can be called with or without local BH being disabled */
 178 static inline int inet_getid(struct inet_peer *p, int more)
 179 {
 180         int old, new;
 181         more++;
 182         inet_peer_refcheck(p);
 183         do {
 184                 old = atomic_read(&p->ip_id_count);
 185                 new = old + more;
 186                 if (!new)
 187                         new = 1;
 188         } while (atomic_cmpxchg(&p->ip_id_count, old, new) != old);
 189         return new;
 190 }
 191
 192 #endif /* _NET_INETPEER_H */