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
  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                 };
  57                 struct rcu_head         rcu;
  58                 struct inet_peer        *gc_next;
  59         };
  60
  61         /* following fields might be frequently dirtied */
  62         __u32                   dtime;  /* the time of last use of not referenced entries */
  63         atomic_t                refcnt;
  64 };
  65
  66 struct inet_peer_base {
  67         struct inet_peer __rcu  *root;
  68         seqlock_t               lock;
  69         u32                     flush_seq;
  70         int                     total;
  71 };
  72
  73 #define INETPEER_BASE_BIT       0x1UL
  74
  75 static inline struct inet_peer *inetpeer_ptr(unsigned long val)
  76 {
  77         BUG_ON(val & INETPEER_BASE_BIT);
  78         return (struct inet_peer *) val;
  79 }
  80
  81 static inline struct inet_peer_base *inetpeer_base_ptr(unsigned long val)
  82 {
  83         if (!(val & INETPEER_BASE_BIT))
  84                 return NULL;
  85         val &= ~INETPEER_BASE_BIT;
  86         return (struct inet_peer_base *) val;
  87 }
  88
  89 static inline bool inetpeer_ptr_is_peer(unsigned long val)
  90 {
  91         return !(val & INETPEER_BASE_BIT);
  92 }
  93
  94 static inline void __inetpeer_ptr_set_peer(unsigned long *val, struct inet_peer *peer)
  95 {
  96         /* This implicitly clears INETPEER_BASE_BIT */
  97         *val = (unsigned long) peer;
  98 }
  99
 100 static inline bool inetpeer_ptr_set_peer(unsigned long *ptr, struct inet_peer *peer)
 101 {
 102         unsigned long val = (unsigned long) peer;
 103         unsigned long orig = *ptr;
 104
 105         if (!(orig & INETPEER_BASE_BIT) ||
 106             cmpxchg(ptr, orig, val) != orig)
 107                 return false;
 108         return true;
 109 }
 110
 111 static inline void inetpeer_init_ptr(unsigned long *ptr, struct inet_peer_base *base)
 112 {
 113         *ptr = (unsigned long) base | INETPEER_BASE_BIT;
 114 }
 115
 116 static inline void inetpeer_transfer_peer(unsigned long *to, unsigned long *from)
 117 {
 118         unsigned long val = *from;
 119
 120         *to = val;
 121         if (inetpeer_ptr_is_peer(val)) {
 122                 struct inet_peer *peer = inetpeer_ptr(val);
 123                 atomic_inc(&peer->refcnt);
 124         }
 125 }
 126
 127 extern void inet_peer_base_init(struct inet_peer_base *);
 128
 129 void                    inet_initpeers(void) __init;
 130
 131 #define INETPEER_METRICS_NEW    (~(u32) 0)
 132
 133 static inline bool inet_metrics_new(const struct inet_peer *p)
 134 {
 135         return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
 136 }
 137
 138 /* can be called with or without local BH being disabled */
 139 struct inet_peer *inet_getpeer(struct inet_peer_base *base,
 140                                const struct inetpeer_addr *daddr,
 141                                int create);
 142
 143 static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base,
 144                                                 __be32 v4daddr,
 145                                                 int create)
 146 {
 147         struct inetpeer_addr daddr;
 148
 149         daddr.addr.a4 = v4daddr;
 150         daddr.family = AF_INET;
 151         return inet_getpeer(base, &daddr, create);
 152 }
 153
 154 static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base,
 155                                                 const struct in6_addr *v6daddr,
 156                                                 int create)
 157 {
 158         struct inetpeer_addr daddr;
 159
 160         *(struct in6_addr *)daddr.addr.a6 = *v6daddr;
 161         daddr.family = AF_INET6;
 162         return inet_getpeer(base, &daddr, create);
 163 }
 164
 165 /* can be called from BH context or outside */
 166 extern void inet_putpeer(struct inet_peer *p);
 167 extern bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
 168
 169 extern void inetpeer_invalidate_tree(struct inet_peer_base *);
 170 extern void inetpeer_invalidate_family(int family);
 171
 172 /*
 173  * temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
 174  * tcp_ts_stamp if no refcount is taken on inet_peer
 175  */
 176 static inline void inet_peer_refcheck(const struct inet_peer *p)
 177 {
 178         WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
 179 }
 180
 181
 182 /* can be called with or without local BH being disabled */
 183 static inline int inet_getid(struct inet_peer *p, int more)
 184 {
 185         int old, new;
 186         more++;
 187         inet_peer_refcheck(p);
 188         do {
 189                 old = atomic_read(&p->ip_id_count);
 190                 new = old + more;
 191                 if (!new)
 192                         new = 1;
 193         } while (atomic_cmpxchg(&p->ip_id_count, old, new) != old);
 194         return new;
 195 }
 196
 197 #endif /* _NET_INETPEER_H */