include/net/inet6_hashtables.h

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  * Authors:     Lotsa people, from code originally in tcp
   7  *
   8  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  */
  13
  14 #ifndef _INET6_HASHTABLES_H
  15 #define _INET6_HASHTABLES_H
  16
  17 #include <linux/config.h>
  18
  19 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
  20 #include <linux/in6.h>
  21 #include <linux/ipv6.h>
  22 #include <linux/types.h>
  23
  24 #include <net/ipv6.h>
  25
  26 struct inet_hashinfo;
  27
  28 /* I have no idea if this is a good hash for v6 or not. -DaveM */
  29 static inline unsigned int inet6_ehashfn(const struct in6_addr *laddr, const u16 lport,
  30                                 const struct in6_addr *faddr, const u16 fport)
  31 {
  32         unsigned int hashent = (lport ^ fport);
  33
  34         hashent ^= (laddr->s6_addr32[3] ^ faddr->s6_addr32[3]);
  35         hashent ^= hashent >> 16;
  36         hashent ^= hashent >> 8;
  37         return hashent;
  38 }
  39
  40 static inline int inet6_sk_ehashfn(const struct sock *sk)
  41 {
  42         const struct inet_sock *inet = inet_sk(sk);
  43         const struct ipv6_pinfo *np = inet6_sk(sk);
  44         const struct in6_addr *laddr = &np->rcv_saddr;
  45         const struct in6_addr *faddr = &np->daddr;
  46         const __u16 lport = inet->num;
  47         const __u16 fport = inet->dport;
  48         return inet6_ehashfn(laddr, lport, faddr, fport);
  49 }
  50
  51 /*
  52  * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
  53  * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
  54  *
  55  * The sockhash lock must be held as a reader here.
  56  */
  57 static inline struct sock *
  58                 __inet6_lookup_established(struct inet_hashinfo *hashinfo,
  59                                            const struct in6_addr *saddr,
  60                                            const u16 sport,
  61                                            const struct in6_addr *daddr,
  62                                            const u16 hnum,
  63                                            const int dif)
  64 {
  65         struct sock *sk;
  66         const struct hlist_node *node;
  67         const __u32 ports = INET_COMBINED_PORTS(sport, hnum);
  68         /* Optimize here for direct hit, only listening connections can
  69          * have wildcards anyways.
  70          */
  71         unsigned int hash = inet6_ehashfn(daddr, hnum, saddr, sport);
  72         struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash);
  73
  74         prefetch(head->chain.first);
  75         read_lock(&head->lock);
  76         sk_for_each(sk, node, &head->chain) {
  77                 /* For IPV6 do the cheaper port and family tests first. */
  78                 if (INET6_MATCH(sk, hash, saddr, daddr, ports, dif))
  79                         goto hit; /* You sunk my battleship! */
  80         }
  81         /* Must check for a TIME_WAIT'er before going to listener hash. */
  82         sk_for_each(sk, node, &(head + hashinfo->ehash_size)->chain) {
  83                 const struct inet_timewait_sock *tw = inet_twsk(sk);
  84
  85                 if(*((__u32 *)&(tw->tw_dport))  == ports        &&
  86                    sk->sk_family                == PF_INET6) {
  87                         const struct tcp6_timewait_sock *tcp6tw = tcp6_twsk(sk);
  88
  89                         if (ipv6_addr_equal(&tcp6tw->tw_v6_daddr, saddr)        &&
  90                             ipv6_addr_equal(&tcp6tw->tw_v6_rcv_saddr, daddr)    &&
  91                             (!sk->sk_bound_dev_if || sk->sk_bound_dev_if == dif))
  92                                 goto hit;
  93                 }
  94         }
  95         read_unlock(&head->lock);
  96         return NULL;
  97
  98 hit:
  99         sock_hold(sk);
 100         read_unlock(&head->lock);
 101         return sk;
 102 }
 103
 104 extern struct sock *inet6_lookup_listener(struct inet_hashinfo *hashinfo,
 105                                           const struct in6_addr *daddr,
 106                                           const unsigned short hnum,
 107                                           const int dif);
 108
 109 static inline struct sock *__inet6_lookup(struct inet_hashinfo *hashinfo,
 110                                           const struct in6_addr *saddr,
 111                                           const u16 sport,
 112                                           const struct in6_addr *daddr,
 113                                           const u16 hnum,
 114                                           const int dif)
 115 {
 116         struct sock *sk = __inet6_lookup_established(hashinfo, saddr, sport,
 117                                                      daddr, hnum, dif);
 118         if (sk)
 119                 return sk;
 120
 121         return inet6_lookup_listener(hashinfo, daddr, hnum, dif);
 122 }
 123
 124 extern struct sock *inet6_lookup(struct inet_hashinfo *hashinfo,
 125                                  const struct in6_addr *saddr, const u16 sport,
 126                                  const struct in6_addr *daddr, const u16 dport,
 127                                  const int dif);
 128 #endif /* defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) */
 129 #endif /* _INET6_HASHTABLES_H */