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 *		Generic INET6 transport hashtables
7 *
8 * Authors:	Lotsa people, from code originally in tcp, generalised here
9 * 		by Arnaldo Carvalho de Melo <acme@mandriva.com>
10 *
11 *	This program is free software; you can redistribute it and/or
12 *      modify it under the terms of the GNU General Public License
13 *      as published by the Free Software Foundation; either version
14 *      2 of the License, or (at your option) any later version.
15 */
16
17#include <linux/module.h>
18#include <linux/random.h>
19
20#include <net/inet_connection_sock.h>
21#include <net/inet_hashtables.h>
22#include <net/inet6_hashtables.h>
23#include <net/ip.h>
24
25void __inet6_hash(struct inet_hashinfo *hashinfo,
26				struct sock *sk)
27{
28	struct hlist_head *list;
29	rwlock_t *lock;
30
31	BUG_TRAP(sk_unhashed(sk));
32
33	if (sk->sk_state == TCP_LISTEN) {
34		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
35		lock = &hashinfo->lhash_lock;
36		inet_listen_wlock(hashinfo);
37	} else {
38		unsigned int hash;
39		sk->sk_hash = hash = inet6_sk_ehashfn(sk);
40		hash &= (hashinfo->ehash_size - 1);
41		list = &hashinfo->ehash[hash].chain;
42		lock = &hashinfo->ehash[hash].lock;
43		write_lock(lock);
44	}
45
46	__sk_add_node(sk, list);
47	sock_prot_inc_use(sk->sk_prot);
48	write_unlock(lock);
49}
50EXPORT_SYMBOL(__inet6_hash);
51
52/*
53 * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
54 * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
55 *
56 * The sockhash lock must be held as a reader here.
57 */
58struct sock *__inet6_lookup_established(struct inet_hashinfo *hashinfo,
59					   const struct in6_addr *saddr,
60					   const __be16 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 __portpair 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->twchain) {
83		const struct inet_timewait_sock *tw = inet_twsk(sk);
84
85		if(*((__portpair *)&(tw->tw_dport))	== ports	&&
86		   sk->sk_family		== PF_INET6) {
87			const struct inet6_timewait_sock *tw6 = inet6_twsk(sk);
88
89			if (ipv6_addr_equal(&tw6->tw_v6_daddr, saddr)	&&
90			    ipv6_addr_equal(&tw6->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
98hit:
99	sock_hold(sk);
100	read_unlock(&head->lock);
101	return sk;
102}
103EXPORT_SYMBOL(__inet6_lookup_established);
104
105struct sock *inet6_lookup_listener(struct inet_hashinfo *hashinfo,
106				   const struct in6_addr *daddr,
107				   const unsigned short hnum, const int dif)
108{
109	struct sock *sk;
110	const struct hlist_node *node;
111	struct sock *result = NULL;
112	int score, hiscore = 0;
113
114	read_lock(&hashinfo->lhash_lock);
115	sk_for_each(sk, node, &hashinfo->listening_hash[inet_lhashfn(hnum)]) {
116		if (inet_sk(sk)->num == hnum && sk->sk_family == PF_INET6) {
117			const struct ipv6_pinfo *np = inet6_sk(sk);
118
119			score = 1;
120			if (!ipv6_addr_any(&np->rcv_saddr)) {
121				if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
122					continue;
123				score++;
124			}
125			if (sk->sk_bound_dev_if) {
126				if (sk->sk_bound_dev_if != dif)
127					continue;
128				score++;
129			}
130			if (score == 3) {
131				result = sk;
132				break;
133			}
134			if (score > hiscore) {
135				hiscore = score;
136				result = sk;
137			}
138		}
139	}
140	if (result)
141		sock_hold(result);
142	read_unlock(&hashinfo->lhash_lock);
143	return result;
144}
145
146EXPORT_SYMBOL_GPL(inet6_lookup_listener);
147
148struct sock *inet6_lookup(struct inet_hashinfo *hashinfo,
149			  const struct in6_addr *saddr, const __be16 sport,
150			  const struct in6_addr *daddr, const __be16 dport,
151			  const int dif)
152{
153	struct sock *sk;
154
155	local_bh_disable();
156	sk = __inet6_lookup(hashinfo, saddr, sport, daddr, ntohs(dport), dif);
157	local_bh_enable();
158
159	return sk;
160}
161
162EXPORT_SYMBOL_GPL(inet6_lookup);
163
164static int __inet6_check_established(struct inet_timewait_death_row *death_row,
165				     struct sock *sk, const __u16 lport,
166				     struct inet_timewait_sock **twp)
167{
168	struct inet_hashinfo *hinfo = death_row->hashinfo;
169	struct inet_sock *inet = inet_sk(sk);
170	const struct ipv6_pinfo *np = inet6_sk(sk);
171	const struct in6_addr *daddr = &np->rcv_saddr;
172	const struct in6_addr *saddr = &np->daddr;
173	const int dif = sk->sk_bound_dev_if;
174	const __portpair ports = INET_COMBINED_PORTS(inet->dport, lport);
175	const unsigned int hash = inet6_ehashfn(daddr, lport, saddr,
176						inet->dport);
177	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
178	struct sock *sk2;
179	const struct hlist_node *node;
180	struct inet_timewait_sock *tw;
181
182	prefetch(head->chain.first);
183	write_lock(&head->lock);
184
185	/* Check TIME-WAIT sockets first. */
186	sk_for_each(sk2, node, &head->twchain) {
187		const struct inet6_timewait_sock *tw6 = inet6_twsk(sk2);
188
189		tw = inet_twsk(sk2);
190
191		if(*((__portpair *)&(tw->tw_dport)) == ports		 &&
192		   sk2->sk_family	       == PF_INET6	 &&
193		   ipv6_addr_equal(&tw6->tw_v6_daddr, saddr)	 &&
194		   ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr) &&
195		   sk2->sk_bound_dev_if == sk->sk_bound_dev_if) {
196			if (twsk_unique(sk, sk2, twp))
197				goto unique;
198			else
199				goto not_unique;
200		}
201	}
202	tw = NULL;
203
204	/* And established part... */
205	sk_for_each(sk2, node, &head->chain) {
206		if (INET6_MATCH(sk2, hash, saddr, daddr, ports, dif))
207			goto not_unique;
208	}
209
210unique:
211	/* Must record num and sport now. Otherwise we will see
212	 * in hash table socket with a funny identity. */
213	inet->num = lport;
214	inet->sport = htons(lport);
215	BUG_TRAP(sk_unhashed(sk));
216	__sk_add_node(sk, &head->chain);
217	sk->sk_hash = hash;
218	sock_prot_inc_use(sk->sk_prot);
219	write_unlock(&head->lock);
220
221	if (twp != NULL) {
222		*twp = tw;
223		NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
224	} else if (tw != NULL) {
225		/* Silly. Should hash-dance instead... */
226		inet_twsk_deschedule(tw, death_row);
227		NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
228
229		inet_twsk_put(tw);
230	}
231	return 0;
232
233not_unique:
234	write_unlock(&head->lock);
235	return -EADDRNOTAVAIL;
236}
237
238static inline u32 inet6_sk_port_offset(const struct sock *sk)
239{
240	const struct inet_sock *inet = inet_sk(sk);
241	const struct ipv6_pinfo *np = inet6_sk(sk);
242	return secure_ipv6_port_ephemeral(np->rcv_saddr.s6_addr32,
243					  np->daddr.s6_addr32,
244					  inet->dport);
245}
246
247int inet6_hash_connect(struct inet_timewait_death_row *death_row,
248		       struct sock *sk)
249{
250	struct inet_hashinfo *hinfo = death_row->hashinfo;
251	const unsigned short snum = inet_sk(sk)->num;
252	struct inet_bind_hashbucket *head;
253	struct inet_bind_bucket *tb;
254	int ret;
255
256	if (snum == 0) {
257		const int low = sysctl_local_port_range[0];
258		const int high = sysctl_local_port_range[1];
259		const int range = high - low;
260		int i, port;
261		static u32 hint;
262		const u32 offset = hint + inet6_sk_port_offset(sk);
263		struct hlist_node *node;
264		struct inet_timewait_sock *tw = NULL;
265
266		local_bh_disable();
267		for (i = 1; i <= range; i++) {
268			port = low + (i + offset) % range;
269			head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)];
270			spin_lock(&head->lock);
271
272			/* Does not bother with rcv_saddr checks,
273			 * because the established check is already
274			 * unique enough.
275			 */
276			inet_bind_bucket_for_each(tb, node, &head->chain) {
277				if (tb->port == port) {
278					BUG_TRAP(!hlist_empty(&tb->owners));
279					if (tb->fastreuse >= 0)
280						goto next_port;
281					if (!__inet6_check_established(death_row,
282								       sk, port,
283								       &tw))
284						goto ok;
285					goto next_port;
286				}
287			}
288
289			tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
290						     head, port);
291			if (!tb) {
292				spin_unlock(&head->lock);
293				break;
294			}
295			tb->fastreuse = -1;
296			goto ok;
297
298		next_port:
299			spin_unlock(&head->lock);
300		}
301		local_bh_enable();
302
303		return -EADDRNOTAVAIL;
304
305ok:
306		hint += i;
307
308		/* Head lock still held and bh's disabled */
309		inet_bind_hash(sk, tb, port);
310		if (sk_unhashed(sk)) {
311			inet_sk(sk)->sport = htons(port);
312			__inet6_hash(hinfo, sk);
313		}
314		spin_unlock(&head->lock);
315
316		if (tw) {
317			inet_twsk_deschedule(tw, death_row);
318			inet_twsk_put(tw);
319		}
320
321		ret = 0;
322		goto out;
323	}
324
325	head = &hinfo->bhash[inet_bhashfn(snum, hinfo->bhash_size)];
326	tb   = inet_csk(sk)->icsk_bind_hash;
327	spin_lock_bh(&head->lock);
328
329	if (sk_head(&tb->owners) == sk && sk->sk_bind_node.next == NULL) {
330		__inet6_hash(hinfo, sk);
331		spin_unlock_bh(&head->lock);
332		return 0;
333	} else {
334		spin_unlock(&head->lock);
335		/* No definite answer... Walk to established hash table */
336		ret = __inet6_check_established(death_row, sk, snum, NULL);
337out:
338		local_bh_enable();
339		return ret;
340	}
341}
342
343EXPORT_SYMBOL_GPL(inet6_hash_connect);
344