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
25struct inet_hashinfo;
26
27static 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 */
43struct 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
51typedef 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
55inet6_ehashfn_t inet6_ehashfn;
56
57INDIRECT_CALLABLE_DECLARE(inet6_ehashfn_t udp6_ehashfn);
58
59struct 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
67struct 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
76struct 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
85static 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
106static inline
107struct 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
146static 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
170struct 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
176int inet6_hash(struct sock *sk);
177
178static 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 */
198