Line data Source code
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 _INET_HASHTABLES_H
11 : #define _INET_HASHTABLES_H
12 :
13 :
14 : #include <linux/interrupt.h>
15 : #include <linux/ip.h>
16 : #include <linux/ipv6.h>
17 : #include <linux/list.h>
18 : #include <linux/slab.h>
19 : #include <linux/socket.h>
20 : #include <linux/spinlock.h>
21 : #include <linux/types.h>
22 : #include <linux/wait.h>
23 :
24 : #include <net/inet_connection_sock.h>
25 : #include <net/inet_sock.h>
26 : #include <net/sock.h>
27 : #include <net/route.h>
28 : #include <net/tcp_states.h>
29 : #include <net/netns/hash.h>
30 :
31 : #include <linux/refcount.h>
32 : #include <asm/byteorder.h>
33 :
34 : /* This is for all connections with a full identity, no wildcards.
35 : * The 'e' prefix stands for Establish, but we really put all sockets
36 : * but LISTEN ones.
37 : */
38 : struct inet_ehash_bucket {
39 : struct hlist_nulls_head chain;
40 : };
41 :
42 : /* There are a few simple rules, which allow for local port reuse by
43 : * an application. In essence:
44 : *
45 : * 1) Sockets bound to different interfaces may share a local port.
46 : * Failing that, goto test 2.
47 : * 2) If all sockets have sk->sk_reuse set, and none of them are in
48 : * TCP_LISTEN state, the port may be shared.
49 : * Failing that, goto test 3.
50 : * 3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local
51 : * address, and none of them are the same, the port may be
52 : * shared.
53 : * Failing this, the port cannot be shared.
54 : *
55 : * The interesting point, is test #2. This is what an FTP server does
56 : * all day. To optimize this case we use a specific flag bit defined
57 : * below. As we add sockets to a bind bucket list, we perform a
58 : * check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN))
59 : * As long as all sockets added to a bind bucket pass this test,
60 : * the flag bit will be set.
61 : * The resulting situation is that tcp_v[46]_verify_bind() can just check
62 : * for this flag bit, if it is set and the socket trying to bind has
63 : * sk->sk_reuse set, we don't even have to walk the owners list at all,
64 : * we return that it is ok to bind this socket to the requested local port.
65 : *
66 : * Sounds like a lot of work, but it is worth it. In a more naive
67 : * implementation (ie. current FreeBSD etc.) the entire list of ports
68 : * must be walked for each data port opened by an ftp server. Needless
69 : * to say, this does not scale at all. With a couple thousand FTP
70 : * users logged onto your box, isn't it nice to know that new data
71 : * ports are created in O(1) time? I thought so. ;-) -DaveM
72 : */
73 : #define FASTREUSEPORT_ANY 1
74 : #define FASTREUSEPORT_STRICT 2
75 :
76 : struct inet_bind_bucket {
77 : possible_net_t ib_net;
78 : int l3mdev;
79 : unsigned short port;
80 : signed char fastreuse;
81 : signed char fastreuseport;
82 : kuid_t fastuid;
83 : #if IS_ENABLED(CONFIG_IPV6)
84 : struct in6_addr fast_v6_rcv_saddr;
85 : #endif
86 : __be32 fast_rcv_saddr;
87 : unsigned short fast_sk_family;
88 : bool fast_ipv6_only;
89 : struct hlist_node node;
90 : struct hlist_head owners;
91 : };
92 :
93 3 : static inline struct net *ib_net(struct inet_bind_bucket *ib)
94 : {
95 3 : return read_pnet(&ib->ib_net);
96 : }
97 :
98 : #define inet_bind_bucket_for_each(tb, head) \
99 : hlist_for_each_entry(tb, head, node)
100 :
101 : struct inet_bind_hashbucket {
102 : spinlock_t lock;
103 : struct hlist_head chain;
104 : };
105 :
106 : /* Sockets can be hashed in established or listening table.
107 : * We must use different 'nulls' end-of-chain value for all hash buckets :
108 : * A socket might transition from ESTABLISH to LISTEN state without
109 : * RCU grace period. A lookup in ehash table needs to handle this case.
110 : */
111 : #define LISTENING_NULLS_BASE (1U << 29)
112 : struct inet_listen_hashbucket {
113 : spinlock_t lock;
114 : unsigned int count;
115 : union {
116 : struct hlist_head head;
117 : struct hlist_nulls_head nulls_head;
118 : };
119 : };
120 :
121 : /* This is for listening sockets, thus all sockets which possess wildcards. */
122 : #define INET_LHTABLE_SIZE 32 /* Yes, really, this is all you need. */
123 :
124 : struct inet_hashinfo {
125 : /* This is for sockets with full identity only. Sockets here will
126 : * always be without wildcards and will have the following invariant:
127 : *
128 : * TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE
129 : *
130 : */
131 : struct inet_ehash_bucket *ehash;
132 : spinlock_t *ehash_locks;
133 : unsigned int ehash_mask;
134 : unsigned int ehash_locks_mask;
135 :
136 : /* Ok, let's try this, I give up, we do need a local binding
137 : * TCP hash as well as the others for fast bind/connect.
138 : */
139 : struct kmem_cache *bind_bucket_cachep;
140 : struct inet_bind_hashbucket *bhash;
141 : unsigned int bhash_size;
142 :
143 : /* The 2nd listener table hashed by local port and address */
144 : unsigned int lhash2_mask;
145 : struct inet_listen_hashbucket *lhash2;
146 :
147 : /* All the above members are written once at bootup and
148 : * never written again _or_ are predominantly read-access.
149 : *
150 : * Now align to a new cache line as all the following members
151 : * might be often dirty.
152 : */
153 : /* All sockets in TCP_LISTEN state will be in listening_hash.
154 : * This is the only table where wildcard'd TCP sockets can
155 : * exist. listening_hash is only hashed by local port number.
156 : * If lhash2 is initialized, the same socket will also be hashed
157 : * to lhash2 by port and address.
158 : */
159 : struct inet_listen_hashbucket listening_hash[INET_LHTABLE_SIZE]
160 : ____cacheline_aligned_in_smp;
161 : };
162 :
163 : #define inet_lhash2_for_each_icsk_rcu(__icsk, list) \
164 : hlist_for_each_entry_rcu(__icsk, list, icsk_listen_portaddr_node)
165 :
166 : static inline struct inet_listen_hashbucket *
167 12 : inet_lhash2_bucket(struct inet_hashinfo *h, u32 hash)
168 : {
169 8 : return &h->lhash2[hash & h->lhash2_mask];
170 : }
171 :
172 8 : static inline struct inet_ehash_bucket *inet_ehash_bucket(
173 : struct inet_hashinfo *hashinfo,
174 : unsigned int hash)
175 : {
176 8 : return &hashinfo->ehash[hash & hashinfo->ehash_mask];
177 : }
178 :
179 11 : static inline spinlock_t *inet_ehash_lockp(
180 : struct inet_hashinfo *hashinfo,
181 : unsigned int hash)
182 : {
183 11 : return &hashinfo->ehash_locks[hash & hashinfo->ehash_locks_mask];
184 : }
185 :
186 : int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo);
187 :
188 : static inline void inet_hashinfo2_free_mod(struct inet_hashinfo *h)
189 : {
190 : kfree(h->lhash2);
191 : h->lhash2 = NULL;
192 : }
193 :
194 : static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo)
195 : {
196 : kvfree(hashinfo->ehash_locks);
197 : hashinfo->ehash_locks = NULL;
198 : }
199 :
200 4 : static inline bool inet_sk_bound_dev_eq(struct net *net, int bound_dev_if,
201 : int dif, int sdif)
202 : {
203 : #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
204 : return inet_bound_dev_eq(!!net->ipv4.sysctl_tcp_l3mdev_accept,
205 : bound_dev_if, dif, sdif);
206 : #else
207 4 : return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
208 : #endif
209 : }
210 :
211 : struct inet_bind_bucket *
212 : inet_bind_bucket_create(struct kmem_cache *cachep, struct net *net,
213 : struct inet_bind_hashbucket *head,
214 : const unsigned short snum, int l3mdev);
215 : void inet_bind_bucket_destroy(struct kmem_cache *cachep,
216 : struct inet_bind_bucket *tb);
217 :
218 14 : static inline u32 inet_bhashfn(const struct net *net, const __u16 lport,
219 : const u32 bhash_size)
220 : {
221 14 : return (lport + net_hash_mix(net)) & (bhash_size - 1);
222 : }
223 :
224 : void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
225 : const unsigned short snum);
226 :
227 : /* These can have wildcards, don't try too hard. */
228 4 : static inline u32 inet_lhashfn(const struct net *net, const unsigned short num)
229 : {
230 4 : return (num + net_hash_mix(net)) & (INET_LHTABLE_SIZE - 1);
231 : }
232 :
233 4 : static inline int inet_sk_listen_hashfn(const struct sock *sk)
234 : {
235 4 : return inet_lhashfn(sock_net(sk), inet_sk(sk)->inet_num);
236 : }
237 :
238 : /* Caller must disable local BH processing. */
239 : int __inet_inherit_port(const struct sock *sk, struct sock *child);
240 :
241 : void inet_put_port(struct sock *sk);
242 :
243 : void inet_hashinfo_init(struct inet_hashinfo *h);
244 : void inet_hashinfo2_init(struct inet_hashinfo *h, const char *name,
245 : unsigned long numentries, int scale,
246 : unsigned long low_limit,
247 : unsigned long high_limit);
248 : int inet_hashinfo2_init_mod(struct inet_hashinfo *h);
249 :
250 : bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk);
251 : bool inet_ehash_nolisten(struct sock *sk, struct sock *osk,
252 : bool *found_dup_sk);
253 : int __inet_hash(struct sock *sk, struct sock *osk);
254 : int inet_hash(struct sock *sk);
255 : void inet_unhash(struct sock *sk);
256 :
257 : struct sock *__inet_lookup_listener(struct net *net,
258 : struct inet_hashinfo *hashinfo,
259 : struct sk_buff *skb, int doff,
260 : const __be32 saddr, const __be16 sport,
261 : const __be32 daddr,
262 : const unsigned short hnum,
263 : const int dif, const int sdif);
264 :
265 0 : static inline struct sock *inet_lookup_listener(struct net *net,
266 : struct inet_hashinfo *hashinfo,
267 : struct sk_buff *skb, int doff,
268 : __be32 saddr, __be16 sport,
269 : __be32 daddr, __be16 dport, int dif, int sdif)
270 : {
271 0 : return __inet_lookup_listener(net, hashinfo, skb, doff, saddr, sport,
272 0 : daddr, ntohs(dport), dif, sdif);
273 : }
274 :
275 : /* Socket demux engine toys. */
276 : /* What happens here is ugly; there's a pair of adjacent fields in
277 : struct inet_sock; __be16 dport followed by __u16 num. We want to
278 : search by pair, so we combine the keys into a single 32bit value
279 : and compare with 32bit value read from &...->dport. Let's at least
280 : make sure that it's not mixed with anything else...
281 : On 64bit targets we combine comparisons with pair of adjacent __be32
282 : fields in the same way.
283 : */
284 : #ifdef __BIG_ENDIAN
285 : #define INET_COMBINED_PORTS(__sport, __dport) \
286 : ((__force __portpair)(((__force __u32)(__be16)(__sport) << 16) | (__u32)(__dport)))
287 : #else /* __LITTLE_ENDIAN */
288 : #define INET_COMBINED_PORTS(__sport, __dport) \
289 : ((__force __portpair)(((__u32)(__dport) << 16) | (__force __u32)(__be16)(__sport)))
290 : #endif
291 :
292 : #if (BITS_PER_LONG == 64)
293 : #ifdef __BIG_ENDIAN
294 : #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
295 : const __addrpair __name = (__force __addrpair) ( \
296 : (((__force __u64)(__be32)(__saddr)) << 32) | \
297 : ((__force __u64)(__be32)(__daddr)))
298 : #else /* __LITTLE_ENDIAN */
299 : #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
300 : const __addrpair __name = (__force __addrpair) ( \
301 : (((__force __u64)(__be32)(__daddr)) << 32) | \
302 : ((__force __u64)(__be32)(__saddr)))
303 : #endif /* __BIG_ENDIAN */
304 : #define INET_MATCH(__sk, __net, __cookie, __saddr, __daddr, __ports, __dif, __sdif) \
305 : (((__sk)->sk_portpair == (__ports)) && \
306 : ((__sk)->sk_addrpair == (__cookie)) && \
307 : (((__sk)->sk_bound_dev_if == (__dif)) || \
308 : ((__sk)->sk_bound_dev_if == (__sdif))) && \
309 : net_eq(sock_net(__sk), (__net)))
310 : #else /* 32-bit arch */
311 : #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
312 : const int __name __deprecated __attribute__((unused))
313 :
314 : #define INET_MATCH(__sk, __net, __cookie, __saddr, __daddr, __ports, __dif, __sdif) \
315 : (((__sk)->sk_portpair == (__ports)) && \
316 : ((__sk)->sk_daddr == (__saddr)) && \
317 : ((__sk)->sk_rcv_saddr == (__daddr)) && \
318 : (((__sk)->sk_bound_dev_if == (__dif)) || \
319 : ((__sk)->sk_bound_dev_if == (__sdif))) && \
320 : net_eq(sock_net(__sk), (__net)))
321 : #endif /* 64-bit arch */
322 :
323 : /* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need
324 : * not check it for lookups anymore, thanks Alexey. -DaveM
325 : */
326 : struct sock *__inet_lookup_established(struct net *net,
327 : struct inet_hashinfo *hashinfo,
328 : const __be32 saddr, const __be16 sport,
329 : const __be32 daddr, const u16 hnum,
330 : const int dif, const int sdif);
331 :
332 : static inline struct sock *
333 : inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo,
334 : const __be32 saddr, const __be16 sport,
335 : const __be32 daddr, const __be16 dport,
336 : const int dif)
337 : {
338 : return __inet_lookup_established(net, hashinfo, saddr, sport, daddr,
339 : ntohs(dport), dif, 0);
340 : }
341 :
342 53 : static inline struct sock *__inet_lookup(struct net *net,
343 : struct inet_hashinfo *hashinfo,
344 : struct sk_buff *skb, int doff,
345 : const __be32 saddr, const __be16 sport,
346 : const __be32 daddr, const __be16 dport,
347 : const int dif, const int sdif,
348 : bool *refcounted)
349 : {
350 53 : u16 hnum = ntohs(dport);
351 53 : struct sock *sk;
352 :
353 53 : sk = __inet_lookup_established(net, hashinfo, saddr, sport,
354 : daddr, hnum, dif, sdif);
355 53 : *refcounted = true;
356 53 : if (sk)
357 : return sk;
358 4 : *refcounted = false;
359 4 : return __inet_lookup_listener(net, hashinfo, skb, doff, saddr,
360 : sport, daddr, hnum, dif, sdif);
361 : }
362 :
363 : static inline struct sock *inet_lookup(struct net *net,
364 : struct inet_hashinfo *hashinfo,
365 : struct sk_buff *skb, int doff,
366 : const __be32 saddr, const __be16 sport,
367 : const __be32 daddr, const __be16 dport,
368 : const int dif)
369 : {
370 : struct sock *sk;
371 : bool refcounted;
372 :
373 : sk = __inet_lookup(net, hashinfo, skb, doff, saddr, sport, daddr,
374 : dport, dif, 0, &refcounted);
375 :
376 : if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt))
377 : sk = NULL;
378 : return sk;
379 : }
380 :
381 438 : static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo,
382 : struct sk_buff *skb,
383 : int doff,
384 : const __be16 sport,
385 : const __be16 dport,
386 : const int sdif,
387 : bool *refcounted)
388 : {
389 438 : struct sock *sk = skb_steal_sock(skb, refcounted);
390 438 : const struct iphdr *iph = ip_hdr(skb);
391 :
392 438 : if (sk)
393 : return sk;
394 :
395 53 : return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo, skb,
396 : doff, iph->saddr, sport,
397 : iph->daddr, dport, inet_iif(skb), sdif,
398 : refcounted);
399 : }
400 :
401 : u32 inet6_ehashfn(const struct net *net,
402 : const struct in6_addr *laddr, const u16 lport,
403 : const struct in6_addr *faddr, const __be16 fport);
404 :
405 8 : static inline void sk_daddr_set(struct sock *sk, __be32 addr)
406 : {
407 8 : sk->sk_daddr = addr; /* alias of inet_daddr */
408 : #if IS_ENABLED(CONFIG_IPV6)
409 : ipv6_addr_set_v4mapped(addr, &sk->sk_v6_daddr);
410 : #endif
411 : }
412 :
413 8 : static inline void sk_rcv_saddr_set(struct sock *sk, __be32 addr)
414 : {
415 8 : sk->sk_rcv_saddr = addr; /* alias of inet_rcv_saddr */
416 : #if IS_ENABLED(CONFIG_IPV6)
417 : ipv6_addr_set_v4mapped(addr, &sk->sk_v6_rcv_saddr);
418 : #endif
419 : }
420 :
421 : int __inet_hash_connect(struct inet_timewait_death_row *death_row,
422 : struct sock *sk, u32 port_offset,
423 : int (*check_established)(struct inet_timewait_death_row *,
424 : struct sock *, __u16,
425 : struct inet_timewait_sock **));
426 :
427 : int inet_hash_connect(struct inet_timewait_death_row *death_row,
428 : struct sock *sk);
429 : #endif /* _INET_HASHTABLES_H */
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