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 *		Generic INET6 transport hashtables
8 *
9 * Authors:	Lotsa people, from code originally in tcp, generalised here
10 *		by Arnaldo Carvalho de Melo <acme@mandriva.com>
11 */
12
13#include <linux/module.h>
14#include <linux/random.h>
15
16#include <net/addrconf.h>
17#include <net/inet_connection_sock.h>
18#include <net/inet_hashtables.h>
19#include <net/inet6_hashtables.h>
20#include <net/secure_seq.h>
21#include <net/ip.h>
22#include <net/sock_reuseport.h>
23
24extern struct inet_hashinfo tcp_hashinfo;
25
26u32 inet6_ehashfn(const struct net *net,
27		  const struct in6_addr *laddr, const u16 lport,
28		  const struct in6_addr *faddr, const __be16 fport)
29{
30	static u32 inet6_ehash_secret __read_mostly;
31	static u32 ipv6_hash_secret __read_mostly;
32
33	u32 lhash, fhash;
34
35	net_get_random_once(&inet6_ehash_secret, sizeof(inet6_ehash_secret));
36	net_get_random_once(&ipv6_hash_secret, sizeof(ipv6_hash_secret));
37
38	lhash = (__force u32)laddr->s6_addr32[3];
39	fhash = __ipv6_addr_jhash(faddr, ipv6_hash_secret);
40
41	return __inet6_ehashfn(lhash, lport, fhash, fport,
42			       inet6_ehash_secret + net_hash_mix(net));
43}
44
45/*
46 * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
47 * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
48 *
49 * The sockhash lock must be held as a reader here.
50 */
51struct sock *__inet6_lookup_established(struct net *net,
52					struct inet_hashinfo *hashinfo,
53					   const struct in6_addr *saddr,
54					   const __be16 sport,
55					   const struct in6_addr *daddr,
56					   const u16 hnum,
57					   const int dif, const int sdif)
58{
59	struct sock *sk;
60	const struct hlist_nulls_node *node;
61	const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
62	/* Optimize here for direct hit, only listening connections can
63	 * have wildcards anyways.
64	 */
65	unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport);
66	unsigned int slot = hash & hashinfo->ehash_mask;
67	struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
68
69
70begin:
71	sk_nulls_for_each_rcu(sk, node, &head->chain) {
72		if (sk->sk_hash != hash)
73			continue;
74		if (!inet6_match(net, sk, saddr, daddr, ports, dif, sdif))
75			continue;
76		if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
77			goto out;
78
79		if (unlikely(!inet6_match(net, sk, saddr, daddr, ports, dif, sdif))) {
80			sock_gen_put(sk);
81			goto begin;
82		}
83		goto found;
84	}
85	if (get_nulls_value(node) != slot)
86		goto begin;
87out:
88	sk = NULL;
89found:
90	return sk;
91}
92EXPORT_SYMBOL(__inet6_lookup_established);
93
94static inline int compute_score(struct sock *sk, struct net *net,
95				const unsigned short hnum,
96				const struct in6_addr *daddr,
97				const int dif, const int sdif)
98{
99	int score = -1;
100
101	if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum &&
102	    sk->sk_family == PF_INET6) {
103		if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
104			return -1;
105
106		if (!inet_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif))
107			return -1;
108
109		score =  sk->sk_bound_dev_if ? 2 : 1;
110		if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
111			score++;
112	}
113	return score;
114}
115
116static inline struct sock *lookup_reuseport(struct net *net, struct sock *sk,
117					    struct sk_buff *skb, int doff,
118					    const struct in6_addr *saddr,
119					    __be16 sport,
120					    const struct in6_addr *daddr,
121					    unsigned short hnum)
122{
123	struct sock *reuse_sk = NULL;
124	u32 phash;
125
126	if (sk->sk_reuseport) {
127		phash = inet6_ehashfn(net, daddr, hnum, saddr, sport);
128		reuse_sk = reuseport_select_sock(sk, phash, skb, doff);
129	}
130	return reuse_sk;
131}
132
133/* called with rcu_read_lock() */
134static struct sock *inet6_lhash2_lookup(struct net *net,
135		struct inet_listen_hashbucket *ilb2,
136		struct sk_buff *skb, int doff,
137		const struct in6_addr *saddr,
138		const __be16 sport, const struct in6_addr *daddr,
139		const unsigned short hnum, const int dif, const int sdif)
140{
141	struct inet_connection_sock *icsk;
142	struct sock *sk, *result = NULL;
143	int score, hiscore = 0;
144
145	inet_lhash2_for_each_icsk_rcu(icsk, &ilb2->head) {
146		sk = (struct sock *)icsk;
147		score = compute_score(sk, net, hnum, daddr, dif, sdif);
148		if (score > hiscore) {
149			result = lookup_reuseport(net, sk, skb, doff,
150						  saddr, sport, daddr, hnum);
151			if (result)
152				return result;
153
154			result = sk;
155			hiscore = score;
156		}
157	}
158
159	return result;
160}
161
162static inline struct sock *inet6_lookup_run_bpf(struct net *net,
163						struct inet_hashinfo *hashinfo,
164						struct sk_buff *skb, int doff,
165						const struct in6_addr *saddr,
166						const __be16 sport,
167						const struct in6_addr *daddr,
168						const u16 hnum)
169{
170	struct sock *sk, *reuse_sk;
171	bool no_reuseport;
172
173	if (hashinfo != &tcp_hashinfo)
174		return NULL; /* only TCP is supported */
175
176	no_reuseport = bpf_sk_lookup_run_v6(net, IPPROTO_TCP,
177					    saddr, sport, daddr, hnum, &sk);
178	if (no_reuseport || IS_ERR_OR_NULL(sk))
179		return sk;
180
181	reuse_sk = lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum);
182	if (reuse_sk)
183		sk = reuse_sk;
184	return sk;
185}
186
187struct sock *inet6_lookup_listener(struct net *net,
188		struct inet_hashinfo *hashinfo,
189		struct sk_buff *skb, int doff,
190		const struct in6_addr *saddr,
191		const __be16 sport, const struct in6_addr *daddr,
192		const unsigned short hnum, const int dif, const int sdif)
193{
194	struct inet_listen_hashbucket *ilb2;
195	struct sock *result = NULL;
196	unsigned int hash2;
197
198	/* Lookup redirect from BPF */
199	if (static_branch_unlikely(&bpf_sk_lookup_enabled)) {
200		result = inet6_lookup_run_bpf(net, hashinfo, skb, doff,
201					      saddr, sport, daddr, hnum);
202		if (result)
203			goto done;
204	}
205
206	hash2 = ipv6_portaddr_hash(net, daddr, hnum);
207	ilb2 = inet_lhash2_bucket(hashinfo, hash2);
208
209	result = inet6_lhash2_lookup(net, ilb2, skb, doff,
210				     saddr, sport, daddr, hnum,
211				     dif, sdif);
212	if (result)
213		goto done;
214
215	/* Lookup lhash2 with in6addr_any */
216	hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum);
217	ilb2 = inet_lhash2_bucket(hashinfo, hash2);
218
219	result = inet6_lhash2_lookup(net, ilb2, skb, doff,
220				     saddr, sport, &in6addr_any, hnum,
221				     dif, sdif);
222done:
223	if (IS_ERR(result))
224		return NULL;
225	return result;
226}
227EXPORT_SYMBOL_GPL(inet6_lookup_listener);
228
229struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo,
230			  struct sk_buff *skb, int doff,
231			  const struct in6_addr *saddr, const __be16 sport,
232			  const struct in6_addr *daddr, const __be16 dport,
233			  const int dif)
234{
235	struct sock *sk;
236	bool refcounted;
237
238	sk = __inet6_lookup(net, hashinfo, skb, doff, saddr, sport, daddr,
239			    ntohs(dport), dif, 0, &refcounted);
240	if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt))
241		sk = NULL;
242	return sk;
243}
244EXPORT_SYMBOL_GPL(inet6_lookup);
245
246static int __inet6_check_established(struct inet_timewait_death_row *death_row,
247				     struct sock *sk, const __u16 lport,
248				     struct inet_timewait_sock **twp)
249{
250	struct inet_hashinfo *hinfo = death_row->hashinfo;
251	struct inet_sock *inet = inet_sk(sk);
252	const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr;
253	const struct in6_addr *saddr = &sk->sk_v6_daddr;
254	const int dif = sk->sk_bound_dev_if;
255	struct net *net = sock_net(sk);
256	const int sdif = l3mdev_master_ifindex_by_index(net, dif);
257	const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
258	const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr,
259						inet->inet_dport);
260	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
261	spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
262	struct sock *sk2;
263	const struct hlist_nulls_node *node;
264	struct inet_timewait_sock *tw = NULL;
265
266	spin_lock(lock);
267
268	sk_nulls_for_each(sk2, node, &head->chain) {
269		if (sk2->sk_hash != hash)
270			continue;
271
272		if (likely(inet6_match(net, sk2, saddr, daddr, ports,
273				       dif, sdif))) {
274			if (sk2->sk_state == TCP_TIME_WAIT) {
275				tw = inet_twsk(sk2);
276				if (twsk_unique(sk, sk2, twp))
277					break;
278			}
279			goto not_unique;
280		}
281	}
282
283	/* Must record num and sport now. Otherwise we will see
284	 * in hash table socket with a funny identity.
285	 */
286	inet->inet_num = lport;
287	inet->inet_sport = htons(lport);
288	sk->sk_hash = hash;
289	WARN_ON(!sk_unhashed(sk));
290	__sk_nulls_add_node_rcu(sk, &head->chain);
291	if (tw) {
292		sk_nulls_del_node_init_rcu((struct sock *)tw);
293		__NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED);
294	}
295	spin_unlock(lock);
296	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
297
298	if (twp) {
299		*twp = tw;
300	} else if (tw) {
301		/* Silly. Should hash-dance instead... */
302		inet_twsk_deschedule_put(tw);
303	}
304	return 0;
305
306not_unique:
307	spin_unlock(lock);
308	return -EADDRNOTAVAIL;
309}
310
311static u64 inet6_sk_port_offset(const struct sock *sk)
312{
313	const struct inet_sock *inet = inet_sk(sk);
314
315	return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32,
316					  sk->sk_v6_daddr.s6_addr32,
317					  inet->inet_dport);
318}
319
320int inet6_hash_connect(struct inet_timewait_death_row *death_row,
321		       struct sock *sk)
322{
323	u64 port_offset = 0;
324
325	if (!inet_sk(sk)->inet_num)
326		port_offset = inet6_sk_port_offset(sk);
327	return __inet_hash_connect(death_row, sk, port_offset,
328				   __inet6_check_established);
329}
330EXPORT_SYMBOL_GPL(inet6_hash_connect);
331
332int inet6_hash(struct sock *sk)
333{
334	int err = 0;
335
336	if (sk->sk_state != TCP_CLOSE)
337		err = __inet_hash(sk, NULL);
338
339	return err;
340}
341EXPORT_SYMBOL_GPL(inet6_hash);
342