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 <asm/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         struct list_head        unused;
  36         __u32                   dtime;          /* the time of last use of not
  37                                                  * referenced entries */
  38         atomic_t                refcnt;
  39         /*
  40          * Once inet_peer is queued for deletion (refcnt == -1), following fields
  41          * are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp, metrics
  42          * We can share memory with rcu_head to help keep inet_peer small.
  43          */
  44         union {
  45                 struct {
  46                         atomic_t                        rid;            /* Frag reception counter */
  47                         atomic_t                        ip_id_count;    /* IP ID for the next packet */
  48                         __u32                           tcp_ts;
  49                         __u32                           tcp_ts_stamp;
  50                         u32                             metrics[RTAX_MAX];
  51                         u32                             rate_tokens;    /* rate limiting for ICMP */
  52                         unsigned long                   rate_last;
  53                         unsigned long                   pmtu_expires;
  54                         u32                             pmtu_orig;
  55                         u32                             pmtu_learned;
  56                         struct inetpeer_addr_base       redirect_learned;
  57                 };
  58                 struct rcu_head         rcu;
  59         };
  60 };
  61
  62 void                    inet_initpeers(void) __init;
  63
  64 #define INETPEER_METRICS_NEW    (~(u32) 0)
  65
  66 static inline bool inet_metrics_new(const struct inet_peer *p)
  67 {
  68         return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
  69 }
  70
  71 /* can be called with or without local BH being disabled */
  72 struct inet_peer        *inet_getpeer(struct inetpeer_addr *daddr, int create);
  73
  74 static inline struct inet_peer *inet_getpeer_v4(__be32 v4daddr, int create)
  75 {
  76         struct inetpeer_addr daddr;
  77
  78         daddr.addr.a4 = v4daddr;
  79         daddr.family = AF_INET;
  80         return inet_getpeer(&daddr, create);
  81 }
  82
  83 static inline struct inet_peer *inet_getpeer_v6(const struct in6_addr *v6daddr, int create)
  84 {
  85         struct inetpeer_addr daddr;
  86
  87         ipv6_addr_copy((struct in6_addr *)daddr.addr.a6, v6daddr);
  88         daddr.family = AF_INET6;
  89         return inet_getpeer(&daddr, create);
  90 }
  91
  92 /* can be called from BH context or outside */
  93 extern void inet_putpeer(struct inet_peer *p);
  94 extern bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
  95
  96 /*
  97  * temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
  98  * tcp_ts_stamp if no refcount is taken on inet_peer
  99  */
 100 static inline void inet_peer_refcheck(const struct inet_peer *p)
 101 {
 102         WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
 103 }
 104
 105
 106 /* can be called with or without local BH being disabled */
 107 static inline __u16     inet_getid(struct inet_peer *p, int more)
 108 {
 109         more++;
 110         inet_peer_refcheck(p);
 111         return atomic_add_return(more, &p->ip_id_count) - more;
 112 }
 113
 114 #endif /* _NET_INETPEER_H */