include/net/inet6_hashtables.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   4  *              operating system.  INET is implemented using the BSD Socket
   5  *              interface as the means of communication with the user level.
   6  *
   7  * Authors:     Lotsa people, from code originally in tcp
   8  */
   9
  10 #ifndef _INET6_HASHTABLES_H
  11 #define _INET6_HASHTABLES_H
  12
  13
  14 #if IS_ENABLED(CONFIG_IPV6)
  15 #include <linux/in6.h>
  16 #include <linux/ipv6.h>
  17 #include <linux/types.h>
  18 #include <linux/jhash.h>
  19
  20 #include <net/inet_sock.h>
  21
  22 #include <net/ipv6.h>
  23 #include <net/netns/hash.h>
  24
  25 struct inet_hashinfo;
  26
  27 static inline unsigned int __inet6_ehashfn(const u32 lhash,
  28                                     const u16 lport,
  29                                     const u32 fhash,
  30                                     const __be16 fport,
  31                                     const u32 initval)
  32 {
  33         const u32 ports = (((u32)lport) << 16) | (__force u32)fport;
  34         return jhash_3words(lhash, fhash, ports, initval);
  35 }
  36
  37 /*
  38  * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
  39  * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
  40  *
  41  * The sockhash lock must be held as a reader here.
  42  */
  43 struct sock *__inet6_lookup_established(struct net *net,
  44                                         struct inet_hashinfo *hashinfo,
  45                                         const struct in6_addr *saddr,
  46                                         const __be16 sport,
  47                                         const struct in6_addr *daddr,
  48                                         const u16 hnum, const int dif,
  49                                         const int sdif);
  50
  51 typedef u32 (inet6_ehashfn_t)(const struct net *net,
  52                                const struct in6_addr *laddr, const u16 lport,
  53                                const struct in6_addr *faddr, const __be16 fport);
  54
  55 inet6_ehashfn_t inet6_ehashfn;
  56
  57 INDIRECT_CALLABLE_DECLARE(inet6_ehashfn_t udp6_ehashfn);
  58
  59 struct sock *inet6_lookup_reuseport(struct net *net, struct sock *sk,
  60                                     struct sk_buff *skb, int doff,
  61                                     const struct in6_addr *saddr,
  62                                     __be16 sport,
  63                                     const struct in6_addr *daddr,
  64                                     unsigned short hnum,
  65                                     inet6_ehashfn_t *ehashfn);
  66
  67 struct sock *inet6_lookup_listener(struct net *net,
  68                                    struct inet_hashinfo *hashinfo,
  69                                    struct sk_buff *skb, int doff,
  70                                    const struct in6_addr *saddr,
  71                                    const __be16 sport,
  72                                    const struct in6_addr *daddr,
  73                                    const unsigned short hnum,
  74                                    const int dif, const int sdif);
  75
  76 struct sock *inet6_lookup_run_sk_lookup(struct net *net,
  77                                         int protocol,
  78                                         struct sk_buff *skb, int doff,
  79                                         const struct in6_addr *saddr,
  80                                         const __be16 sport,
  81                                         const struct in6_addr *daddr,
  82                                         const u16 hnum, const int dif,
  83                                         inet6_ehashfn_t *ehashfn);
  84
  85 static inline struct sock *__inet6_lookup(struct net *net,
  86                                           struct inet_hashinfo *hashinfo,
  87                                           struct sk_buff *skb, int doff,
  88                                           const struct in6_addr *saddr,
  89                                           const __be16 sport,
  90                                           const struct in6_addr *daddr,
  91                                           const u16 hnum,
  92                                           const int dif, const int sdif,
  93                                           bool *refcounted)
  94 {
  95         struct sock *sk = __inet6_lookup_established(net, hashinfo, saddr,
  96                                                      sport, daddr, hnum,
  97                                                      dif, sdif);
  98         *refcounted = true;
  99         if (sk)
 100                 return sk;
 101         *refcounted = false;
 102         return inet6_lookup_listener(net, hashinfo, skb, doff, saddr, sport,
 103                                      daddr, hnum, dif, sdif);
 104 }
 105
 106 static inline
 107 struct sock *inet6_steal_sock(struct net *net, struct sk_buff *skb, int doff,
 108                               const struct in6_addr *saddr, const __be16 sport,
 109                               const struct in6_addr *daddr, const __be16 dport,
 110                               bool *refcounted, inet6_ehashfn_t *ehashfn)
 111 {
 112         struct sock *sk, *reuse_sk;
 113         bool prefetched;
 114
 115         sk = skb_steal_sock(skb, refcounted, &prefetched);
 116         if (!sk)
 117                 return NULL;
 118
 119         if (!prefetched || !sk_fullsock(sk))
 120                 return sk;
 121
 122         if (sk->sk_protocol == IPPROTO_TCP) {
 123                 if (sk->sk_state != TCP_LISTEN)
 124                         return sk;
 125         } else if (sk->sk_protocol == IPPROTO_UDP) {
 126                 if (sk->sk_state != TCP_CLOSE)
 127                         return sk;
 128         } else {
 129                 return sk;
 130         }
 131
 132         reuse_sk = inet6_lookup_reuseport(net, sk, skb, doff,
 133                                           saddr, sport, daddr, ntohs(dport),
 134                                           ehashfn);
 135         if (!reuse_sk)
 136                 return sk;
 137
 138         /* We've chosen a new reuseport sock which is never refcounted. This
 139          * implies that sk also isn't refcounted.
 140          */
 141         WARN_ON_ONCE(*refcounted);
 142
 143         return reuse_sk;
 144 }
 145
 146 static inline struct sock *__inet6_lookup_skb(struct inet_hashinfo *hashinfo,
 147                                               struct sk_buff *skb, int doff,
 148                                               const __be16 sport,
 149                                               const __be16 dport,
 150                                               int iif, int sdif,
 151                                               bool *refcounted)
 152 {
 153         struct net *net = dev_net(skb_dst(skb)->dev);
 154         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 155         struct sock *sk;
 156
 157         sk = inet6_steal_sock(net, skb, doff, &ip6h->saddr, sport, &ip6h->daddr, dport,
 158                               refcounted, inet6_ehashfn);
 159         if (IS_ERR(sk))
 160                 return NULL;
 161         if (sk)
 162                 return sk;
 163
 164         return __inet6_lookup(net, hashinfo, skb,
 165                               doff, &ip6h->saddr, sport,
 166                               &ip6h->daddr, ntohs(dport),
 167                               iif, sdif, refcounted);
 168 }
 169
 170 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo,
 171                           struct sk_buff *skb, int doff,
 172                           const struct in6_addr *saddr, const __be16 sport,
 173                           const struct in6_addr *daddr, const __be16 dport,
 174                           const int dif);
 175
 176 int inet6_hash(struct sock *sk);
 177
 178 static inline bool inet6_match(struct net *net, const struct sock *sk,
 179                                const struct in6_addr *saddr,
 180                                const struct in6_addr *daddr,
 181                                const __portpair ports,
 182                                const int dif, const int sdif)
 183 {
 184         if (!net_eq(sock_net(sk), net) ||
 185             sk->sk_family != AF_INET6 ||
 186             sk->sk_portpair != ports ||
 187             !ipv6_addr_equal(&sk->sk_v6_daddr, saddr) ||
 188             !ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
 189                 return false;
 190
 191         /* READ_ONCE() paired with WRITE_ONCE() in sock_bindtoindex_locked() */
 192         return inet_sk_bound_dev_eq(net, READ_ONCE(sk->sk_bound_dev_if), dif,
 193                                     sdif);
 194 }
 195 #endif /* IS_ENABLED(CONFIG_IPV6) */
 196
 197 #endif /* _INET6_HASHTABLES_H */