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 | * Support for INET connection oriented protocols. |
8 | * |
9 | * Authors: See the TCP sources |
10 | */ |
11 | |
12 | #include <linux/module.h> |
13 | #include <linux/jhash.h> |
14 | |
15 | #include <net/inet_connection_sock.h> |
16 | #include <net/inet_hashtables.h> |
17 | #include <net/inet_timewait_sock.h> |
18 | #include <net/ip.h> |
19 | #include <net/route.h> |
20 | #include <net/tcp_states.h> |
21 | #include <net/xfrm.h> |
22 | #include <net/tcp.h> |
23 | #include <net/sock_reuseport.h> |
24 | #include <net/addrconf.h> |
25 | |
26 | #if IS_ENABLED(CONFIG_IPV6) |
27 | /* match_sk*_wildcard == true: IPV6_ADDR_ANY equals to any IPv6 addresses |
28 | * if IPv6 only, and any IPv4 addresses |
29 | * if not IPv6 only |
30 | * match_sk*_wildcard == false: addresses must be exactly the same, i.e. |
31 | * IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY, |
32 | * and 0.0.0.0 equals to 0.0.0.0 only |
33 | */ |
34 | static bool ipv6_rcv_saddr_equal(const struct in6_addr *sk1_rcv_saddr6, |
35 | const struct in6_addr *sk2_rcv_saddr6, |
36 | __be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr, |
37 | bool sk1_ipv6only, bool sk2_ipv6only, |
38 | bool match_sk1_wildcard, |
39 | bool match_sk2_wildcard) |
40 | { |
41 | int addr_type = ipv6_addr_type(addr: sk1_rcv_saddr6); |
42 | int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(addr: sk2_rcv_saddr6) : IPV6_ADDR_MAPPED; |
43 | |
44 | /* if both are mapped, treat as IPv4 */ |
45 | if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) { |
46 | if (!sk2_ipv6only) { |
47 | if (sk1_rcv_saddr == sk2_rcv_saddr) |
48 | return true; |
49 | return (match_sk1_wildcard && !sk1_rcv_saddr) || |
50 | (match_sk2_wildcard && !sk2_rcv_saddr); |
51 | } |
52 | return false; |
53 | } |
54 | |
55 | if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY) |
56 | return true; |
57 | |
58 | if (addr_type2 == IPV6_ADDR_ANY && match_sk2_wildcard && |
59 | !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED)) |
60 | return true; |
61 | |
62 | if (addr_type == IPV6_ADDR_ANY && match_sk1_wildcard && |
63 | !(sk1_ipv6only && addr_type2 == IPV6_ADDR_MAPPED)) |
64 | return true; |
65 | |
66 | if (sk2_rcv_saddr6 && |
67 | ipv6_addr_equal(a1: sk1_rcv_saddr6, a2: sk2_rcv_saddr6)) |
68 | return true; |
69 | |
70 | return false; |
71 | } |
72 | #endif |
73 | |
74 | /* match_sk*_wildcard == true: 0.0.0.0 equals to any IPv4 addresses |
75 | * match_sk*_wildcard == false: addresses must be exactly the same, i.e. |
76 | * 0.0.0.0 only equals to 0.0.0.0 |
77 | */ |
78 | static bool ipv4_rcv_saddr_equal(__be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr, |
79 | bool sk2_ipv6only, bool match_sk1_wildcard, |
80 | bool match_sk2_wildcard) |
81 | { |
82 | if (!sk2_ipv6only) { |
83 | if (sk1_rcv_saddr == sk2_rcv_saddr) |
84 | return true; |
85 | return (match_sk1_wildcard && !sk1_rcv_saddr) || |
86 | (match_sk2_wildcard && !sk2_rcv_saddr); |
87 | } |
88 | return false; |
89 | } |
90 | |
91 | bool inet_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2, |
92 | bool match_wildcard) |
93 | { |
94 | #if IS_ENABLED(CONFIG_IPV6) |
95 | if (sk->sk_family == AF_INET6) |
96 | return ipv6_rcv_saddr_equal(sk1_rcv_saddr6: &sk->sk_v6_rcv_saddr, |
97 | sk2_rcv_saddr6: inet6_rcv_saddr(sk: sk2), |
98 | sk1_rcv_saddr: sk->sk_rcv_saddr, |
99 | sk2_rcv_saddr: sk2->sk_rcv_saddr, |
100 | ipv6_only_sock(sk), |
101 | ipv6_only_sock(sk2), |
102 | match_sk1_wildcard: match_wildcard, |
103 | match_sk2_wildcard: match_wildcard); |
104 | #endif |
105 | return ipv4_rcv_saddr_equal(sk1_rcv_saddr: sk->sk_rcv_saddr, sk2_rcv_saddr: sk2->sk_rcv_saddr, |
106 | ipv6_only_sock(sk2), match_sk1_wildcard: match_wildcard, |
107 | match_sk2_wildcard: match_wildcard); |
108 | } |
109 | EXPORT_SYMBOL(inet_rcv_saddr_equal); |
110 | |
111 | bool inet_rcv_saddr_any(const struct sock *sk) |
112 | { |
113 | #if IS_ENABLED(CONFIG_IPV6) |
114 | if (sk->sk_family == AF_INET6) |
115 | return ipv6_addr_any(a: &sk->sk_v6_rcv_saddr); |
116 | #endif |
117 | return !sk->sk_rcv_saddr; |
118 | } |
119 | |
120 | void inet_get_local_port_range(const struct net *net, int *low, int *high) |
121 | { |
122 | unsigned int seq; |
123 | |
124 | do { |
125 | seq = read_seqbegin(sl: &net->ipv4.ip_local_ports.lock); |
126 | |
127 | *low = net->ipv4.ip_local_ports.range[0]; |
128 | *high = net->ipv4.ip_local_ports.range[1]; |
129 | } while (read_seqretry(sl: &net->ipv4.ip_local_ports.lock, start: seq)); |
130 | } |
131 | EXPORT_SYMBOL(inet_get_local_port_range); |
132 | |
133 | void inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high) |
134 | { |
135 | const struct inet_sock *inet = inet_sk(sk); |
136 | const struct net *net = sock_net(sk); |
137 | int lo, hi, sk_lo, sk_hi; |
138 | |
139 | inet_get_local_port_range(net, &lo, &hi); |
140 | |
141 | sk_lo = inet->local_port_range.lo; |
142 | sk_hi = inet->local_port_range.hi; |
143 | |
144 | if (unlikely(lo <= sk_lo && sk_lo <= hi)) |
145 | lo = sk_lo; |
146 | if (unlikely(lo <= sk_hi && sk_hi <= hi)) |
147 | hi = sk_hi; |
148 | |
149 | *low = lo; |
150 | *high = hi; |
151 | } |
152 | EXPORT_SYMBOL(inet_sk_get_local_port_range); |
153 | |
154 | static bool inet_use_bhash2_on_bind(const struct sock *sk) |
155 | { |
156 | #if IS_ENABLED(CONFIG_IPV6) |
157 | if (sk->sk_family == AF_INET6) { |
158 | int addr_type = ipv6_addr_type(addr: &sk->sk_v6_rcv_saddr); |
159 | |
160 | return addr_type != IPV6_ADDR_ANY && |
161 | addr_type != IPV6_ADDR_MAPPED; |
162 | } |
163 | #endif |
164 | return sk->sk_rcv_saddr != htonl(INADDR_ANY); |
165 | } |
166 | |
167 | static bool inet_bind_conflict(const struct sock *sk, struct sock *sk2, |
168 | kuid_t sk_uid, bool relax, |
169 | bool reuseport_cb_ok, bool reuseport_ok) |
170 | { |
171 | int bound_dev_if2; |
172 | |
173 | if (sk == sk2) |
174 | return false; |
175 | |
176 | bound_dev_if2 = READ_ONCE(sk2->sk_bound_dev_if); |
177 | |
178 | if (!sk->sk_bound_dev_if || !bound_dev_if2 || |
179 | sk->sk_bound_dev_if == bound_dev_if2) { |
180 | if (sk->sk_reuse && sk2->sk_reuse && |
181 | sk2->sk_state != TCP_LISTEN) { |
182 | if (!relax || (!reuseport_ok && sk->sk_reuseport && |
183 | sk2->sk_reuseport && reuseport_cb_ok && |
184 | (sk2->sk_state == TCP_TIME_WAIT || |
185 | uid_eq(left: sk_uid, right: sock_i_uid(sk: sk2))))) |
186 | return true; |
187 | } else if (!reuseport_ok || !sk->sk_reuseport || |
188 | !sk2->sk_reuseport || !reuseport_cb_ok || |
189 | (sk2->sk_state != TCP_TIME_WAIT && |
190 | !uid_eq(left: sk_uid, right: sock_i_uid(sk: sk2)))) { |
191 | return true; |
192 | } |
193 | } |
194 | return false; |
195 | } |
196 | |
197 | static bool __inet_bhash2_conflict(const struct sock *sk, struct sock *sk2, |
198 | kuid_t sk_uid, bool relax, |
199 | bool reuseport_cb_ok, bool reuseport_ok) |
200 | { |
201 | if (sk->sk_family == AF_INET && ipv6_only_sock(sk2)) |
202 | return false; |
203 | |
204 | return inet_bind_conflict(sk, sk2, sk_uid, relax, |
205 | reuseport_cb_ok, reuseport_ok); |
206 | } |
207 | |
208 | static bool inet_bhash2_conflict(const struct sock *sk, |
209 | const struct inet_bind2_bucket *tb2, |
210 | kuid_t sk_uid, |
211 | bool relax, bool reuseport_cb_ok, |
212 | bool reuseport_ok) |
213 | { |
214 | struct inet_timewait_sock *tw2; |
215 | struct sock *sk2; |
216 | |
217 | sk_for_each_bound_bhash2(sk2, &tb2->owners) { |
218 | if (__inet_bhash2_conflict(sk, sk2, sk_uid, relax, |
219 | reuseport_cb_ok, reuseport_ok)) |
220 | return true; |
221 | } |
222 | |
223 | twsk_for_each_bound_bhash2(tw2, &tb2->deathrow) { |
224 | sk2 = (struct sock *)tw2; |
225 | |
226 | if (__inet_bhash2_conflict(sk, sk2, sk_uid, relax, |
227 | reuseport_cb_ok, reuseport_ok)) |
228 | return true; |
229 | } |
230 | |
231 | return false; |
232 | } |
233 | |
234 | /* This should be called only when the tb and tb2 hashbuckets' locks are held */ |
235 | static int inet_csk_bind_conflict(const struct sock *sk, |
236 | const struct inet_bind_bucket *tb, |
237 | const struct inet_bind2_bucket *tb2, /* may be null */ |
238 | bool relax, bool reuseport_ok) |
239 | { |
240 | bool reuseport_cb_ok; |
241 | struct sock_reuseport *reuseport_cb; |
242 | kuid_t uid = sock_i_uid(sk: (struct sock *)sk); |
243 | |
244 | rcu_read_lock(); |
245 | reuseport_cb = rcu_dereference(sk->sk_reuseport_cb); |
246 | /* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */ |
247 | reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks); |
248 | rcu_read_unlock(); |
249 | |
250 | /* |
251 | * Unlike other sk lookup places we do not check |
252 | * for sk_net here, since _all_ the socks listed |
253 | * in tb->owners and tb2->owners list belong |
254 | * to the same net - the one this bucket belongs to. |
255 | */ |
256 | |
257 | if (!inet_use_bhash2_on_bind(sk)) { |
258 | struct sock *sk2; |
259 | |
260 | sk_for_each_bound(sk2, &tb->owners) |
261 | if (inet_bind_conflict(sk, sk2, sk_uid: uid, relax, |
262 | reuseport_cb_ok, reuseport_ok) && |
263 | inet_rcv_saddr_equal(sk, sk2, true)) |
264 | return true; |
265 | |
266 | return false; |
267 | } |
268 | |
269 | /* Conflicts with an existing IPV6_ADDR_ANY (if ipv6) or INADDR_ANY (if |
270 | * ipv4) should have been checked already. We need to do these two |
271 | * checks separately because their spinlocks have to be acquired/released |
272 | * independently of each other, to prevent possible deadlocks |
273 | */ |
274 | return tb2 && inet_bhash2_conflict(sk, tb2, sk_uid: uid, relax, reuseport_cb_ok, |
275 | reuseport_ok); |
276 | } |
277 | |
278 | /* Determine if there is a bind conflict with an existing IPV6_ADDR_ANY (if ipv6) or |
279 | * INADDR_ANY (if ipv4) socket. |
280 | * |
281 | * Caller must hold bhash hashbucket lock with local bh disabled, to protect |
282 | * against concurrent binds on the port for addr any |
283 | */ |
284 | static bool inet_bhash2_addr_any_conflict(const struct sock *sk, int port, int l3mdev, |
285 | bool relax, bool reuseport_ok) |
286 | { |
287 | kuid_t uid = sock_i_uid(sk: (struct sock *)sk); |
288 | const struct net *net = sock_net(sk); |
289 | struct sock_reuseport *reuseport_cb; |
290 | struct inet_bind_hashbucket *head2; |
291 | struct inet_bind2_bucket *tb2; |
292 | bool reuseport_cb_ok; |
293 | |
294 | rcu_read_lock(); |
295 | reuseport_cb = rcu_dereference(sk->sk_reuseport_cb); |
296 | /* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */ |
297 | reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks); |
298 | rcu_read_unlock(); |
299 | |
300 | head2 = inet_bhash2_addr_any_hashbucket(sk, net, port); |
301 | |
302 | spin_lock(lock: &head2->lock); |
303 | |
304 | inet_bind_bucket_for_each(tb2, &head2->chain) |
305 | if (inet_bind2_bucket_match_addr_any(tb: tb2, net, port, l3mdev, sk)) |
306 | break; |
307 | |
308 | if (tb2 && inet_bhash2_conflict(sk, tb2, sk_uid: uid, relax, reuseport_cb_ok, |
309 | reuseport_ok)) { |
310 | spin_unlock(lock: &head2->lock); |
311 | return true; |
312 | } |
313 | |
314 | spin_unlock(lock: &head2->lock); |
315 | return false; |
316 | } |
317 | |
318 | /* |
319 | * Find an open port number for the socket. Returns with the |
320 | * inet_bind_hashbucket locks held if successful. |
321 | */ |
322 | static struct inet_bind_hashbucket * |
323 | inet_csk_find_open_port(const struct sock *sk, struct inet_bind_bucket **tb_ret, |
324 | struct inet_bind2_bucket **tb2_ret, |
325 | struct inet_bind_hashbucket **head2_ret, int *port_ret) |
326 | { |
327 | struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk); |
328 | int i, low, high, attempt_half, port, l3mdev; |
329 | struct inet_bind_hashbucket *head, *head2; |
330 | struct net *net = sock_net(sk); |
331 | struct inet_bind2_bucket *tb2; |
332 | struct inet_bind_bucket *tb; |
333 | u32 remaining, offset; |
334 | bool relax = false; |
335 | |
336 | l3mdev = inet_sk_bound_l3mdev(sk); |
337 | ports_exhausted: |
338 | attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0; |
339 | other_half_scan: |
340 | inet_sk_get_local_port_range(sk, &low, &high); |
341 | high++; /* [32768, 60999] -> [32768, 61000[ */ |
342 | if (high - low < 4) |
343 | attempt_half = 0; |
344 | if (attempt_half) { |
345 | int half = low + (((high - low) >> 2) << 1); |
346 | |
347 | if (attempt_half == 1) |
348 | high = half; |
349 | else |
350 | low = half; |
351 | } |
352 | remaining = high - low; |
353 | if (likely(remaining > 1)) |
354 | remaining &= ~1U; |
355 | |
356 | offset = get_random_u32_below(ceil: remaining); |
357 | /* __inet_hash_connect() favors ports having @low parity |
358 | * We do the opposite to not pollute connect() users. |
359 | */ |
360 | offset |= 1U; |
361 | |
362 | other_parity_scan: |
363 | port = low + offset; |
364 | for (i = 0; i < remaining; i += 2, port += 2) { |
365 | if (unlikely(port >= high)) |
366 | port -= remaining; |
367 | if (inet_is_local_reserved_port(net, port)) |
368 | continue; |
369 | head = &hinfo->bhash[inet_bhashfn(net, lport: port, |
370 | bhash_size: hinfo->bhash_size)]; |
371 | spin_lock_bh(lock: &head->lock); |
372 | if (inet_use_bhash2_on_bind(sk)) { |
373 | if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, relax, reuseport_ok: false)) |
374 | goto next_port; |
375 | } |
376 | |
377 | head2 = inet_bhashfn_portaddr(hinfo, sk, net, port); |
378 | spin_lock(lock: &head2->lock); |
379 | tb2 = inet_bind2_bucket_find(head: head2, net, port, l3mdev, sk); |
380 | inet_bind_bucket_for_each(tb, &head->chain) |
381 | if (inet_bind_bucket_match(tb, net, port, l3mdev)) { |
382 | if (!inet_csk_bind_conflict(sk, tb, tb2, |
383 | relax, reuseport_ok: false)) |
384 | goto success; |
385 | spin_unlock(lock: &head2->lock); |
386 | goto next_port; |
387 | } |
388 | tb = NULL; |
389 | goto success; |
390 | next_port: |
391 | spin_unlock_bh(lock: &head->lock); |
392 | cond_resched(); |
393 | } |
394 | |
395 | offset--; |
396 | if (!(offset & 1)) |
397 | goto other_parity_scan; |
398 | |
399 | if (attempt_half == 1) { |
400 | /* OK we now try the upper half of the range */ |
401 | attempt_half = 2; |
402 | goto other_half_scan; |
403 | } |
404 | |
405 | if (READ_ONCE(net->ipv4.sysctl_ip_autobind_reuse) && !relax) { |
406 | /* We still have a chance to connect to different destinations */ |
407 | relax = true; |
408 | goto ports_exhausted; |
409 | } |
410 | return NULL; |
411 | success: |
412 | *port_ret = port; |
413 | *tb_ret = tb; |
414 | *tb2_ret = tb2; |
415 | *head2_ret = head2; |
416 | return head; |
417 | } |
418 | |
419 | static inline int sk_reuseport_match(struct inet_bind_bucket *tb, |
420 | struct sock *sk) |
421 | { |
422 | kuid_t uid = sock_i_uid(sk); |
423 | |
424 | if (tb->fastreuseport <= 0) |
425 | return 0; |
426 | if (!sk->sk_reuseport) |
427 | return 0; |
428 | if (rcu_access_pointer(sk->sk_reuseport_cb)) |
429 | return 0; |
430 | if (!uid_eq(left: tb->fastuid, right: uid)) |
431 | return 0; |
432 | /* We only need to check the rcv_saddr if this tb was once marked |
433 | * without fastreuseport and then was reset, as we can only know that |
434 | * the fast_*rcv_saddr doesn't have any conflicts with the socks on the |
435 | * owners list. |
436 | */ |
437 | if (tb->fastreuseport == FASTREUSEPORT_ANY) |
438 | return 1; |
439 | #if IS_ENABLED(CONFIG_IPV6) |
440 | if (tb->fast_sk_family == AF_INET6) |
441 | return ipv6_rcv_saddr_equal(sk1_rcv_saddr6: &tb->fast_v6_rcv_saddr, |
442 | sk2_rcv_saddr6: inet6_rcv_saddr(sk), |
443 | sk1_rcv_saddr: tb->fast_rcv_saddr, |
444 | sk2_rcv_saddr: sk->sk_rcv_saddr, |
445 | sk1_ipv6only: tb->fast_ipv6_only, |
446 | ipv6_only_sock(sk), match_sk1_wildcard: true, match_sk2_wildcard: false); |
447 | #endif |
448 | return ipv4_rcv_saddr_equal(sk1_rcv_saddr: tb->fast_rcv_saddr, sk2_rcv_saddr: sk->sk_rcv_saddr, |
449 | ipv6_only_sock(sk), match_sk1_wildcard: true, match_sk2_wildcard: false); |
450 | } |
451 | |
452 | void inet_csk_update_fastreuse(struct inet_bind_bucket *tb, |
453 | struct sock *sk) |
454 | { |
455 | kuid_t uid = sock_i_uid(sk); |
456 | bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN; |
457 | |
458 | if (hlist_empty(h: &tb->owners)) { |
459 | tb->fastreuse = reuse; |
460 | if (sk->sk_reuseport) { |
461 | tb->fastreuseport = FASTREUSEPORT_ANY; |
462 | tb->fastuid = uid; |
463 | tb->fast_rcv_saddr = sk->sk_rcv_saddr; |
464 | tb->fast_ipv6_only = ipv6_only_sock(sk); |
465 | tb->fast_sk_family = sk->sk_family; |
466 | #if IS_ENABLED(CONFIG_IPV6) |
467 | tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr; |
468 | #endif |
469 | } else { |
470 | tb->fastreuseport = 0; |
471 | } |
472 | } else { |
473 | if (!reuse) |
474 | tb->fastreuse = 0; |
475 | if (sk->sk_reuseport) { |
476 | /* We didn't match or we don't have fastreuseport set on |
477 | * the tb, but we have sk_reuseport set on this socket |
478 | * and we know that there are no bind conflicts with |
479 | * this socket in this tb, so reset our tb's reuseport |
480 | * settings so that any subsequent sockets that match |
481 | * our current socket will be put on the fast path. |
482 | * |
483 | * If we reset we need to set FASTREUSEPORT_STRICT so we |
484 | * do extra checking for all subsequent sk_reuseport |
485 | * socks. |
486 | */ |
487 | if (!sk_reuseport_match(tb, sk)) { |
488 | tb->fastreuseport = FASTREUSEPORT_STRICT; |
489 | tb->fastuid = uid; |
490 | tb->fast_rcv_saddr = sk->sk_rcv_saddr; |
491 | tb->fast_ipv6_only = ipv6_only_sock(sk); |
492 | tb->fast_sk_family = sk->sk_family; |
493 | #if IS_ENABLED(CONFIG_IPV6) |
494 | tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr; |
495 | #endif |
496 | } |
497 | } else { |
498 | tb->fastreuseport = 0; |
499 | } |
500 | } |
501 | } |
502 | |
503 | /* Obtain a reference to a local port for the given sock, |
504 | * if snum is zero it means select any available local port. |
505 | * We try to allocate an odd port (and leave even ports for connect()) |
506 | */ |
507 | int inet_csk_get_port(struct sock *sk, unsigned short snum) |
508 | { |
509 | struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk); |
510 | bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN; |
511 | bool found_port = false, check_bind_conflict = true; |
512 | bool bhash_created = false, bhash2_created = false; |
513 | int ret = -EADDRINUSE, port = snum, l3mdev; |
514 | struct inet_bind_hashbucket *head, *head2; |
515 | struct inet_bind2_bucket *tb2 = NULL; |
516 | struct inet_bind_bucket *tb = NULL; |
517 | bool head2_lock_acquired = false; |
518 | struct net *net = sock_net(sk); |
519 | |
520 | l3mdev = inet_sk_bound_l3mdev(sk); |
521 | |
522 | if (!port) { |
523 | head = inet_csk_find_open_port(sk, tb_ret: &tb, tb2_ret: &tb2, head2_ret: &head2, port_ret: &port); |
524 | if (!head) |
525 | return ret; |
526 | |
527 | head2_lock_acquired = true; |
528 | |
529 | if (tb && tb2) |
530 | goto success; |
531 | found_port = true; |
532 | } else { |
533 | head = &hinfo->bhash[inet_bhashfn(net, lport: port, |
534 | bhash_size: hinfo->bhash_size)]; |
535 | spin_lock_bh(lock: &head->lock); |
536 | inet_bind_bucket_for_each(tb, &head->chain) |
537 | if (inet_bind_bucket_match(tb, net, port, l3mdev)) |
538 | break; |
539 | } |
540 | |
541 | if (!tb) { |
542 | tb = inet_bind_bucket_create(cachep: hinfo->bind_bucket_cachep, net, |
543 | head, snum: port, l3mdev); |
544 | if (!tb) |
545 | goto fail_unlock; |
546 | bhash_created = true; |
547 | } |
548 | |
549 | if (!found_port) { |
550 | if (!hlist_empty(h: &tb->owners)) { |
551 | if (sk->sk_reuse == SK_FORCE_REUSE || |
552 | (tb->fastreuse > 0 && reuse) || |
553 | sk_reuseport_match(tb, sk)) |
554 | check_bind_conflict = false; |
555 | } |
556 | |
557 | if (check_bind_conflict && inet_use_bhash2_on_bind(sk)) { |
558 | if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, relax: true, reuseport_ok: true)) |
559 | goto fail_unlock; |
560 | } |
561 | |
562 | head2 = inet_bhashfn_portaddr(hinfo, sk, net, port); |
563 | spin_lock(lock: &head2->lock); |
564 | head2_lock_acquired = true; |
565 | tb2 = inet_bind2_bucket_find(head: head2, net, port, l3mdev, sk); |
566 | } |
567 | |
568 | if (!tb2) { |
569 | tb2 = inet_bind2_bucket_create(cachep: hinfo->bind2_bucket_cachep, |
570 | net, head: head2, port, l3mdev, sk); |
571 | if (!tb2) |
572 | goto fail_unlock; |
573 | bhash2_created = true; |
574 | } |
575 | |
576 | if (!found_port && check_bind_conflict) { |
577 | if (inet_csk_bind_conflict(sk, tb, tb2, relax: true, reuseport_ok: true)) |
578 | goto fail_unlock; |
579 | } |
580 | |
581 | success: |
582 | inet_csk_update_fastreuse(tb, sk); |
583 | |
584 | if (!inet_csk(sk)->icsk_bind_hash) |
585 | inet_bind_hash(sk, tb, tb2, port); |
586 | WARN_ON(inet_csk(sk)->icsk_bind_hash != tb); |
587 | WARN_ON(inet_csk(sk)->icsk_bind2_hash != tb2); |
588 | ret = 0; |
589 | |
590 | fail_unlock: |
591 | if (ret) { |
592 | if (bhash_created) |
593 | inet_bind_bucket_destroy(cachep: hinfo->bind_bucket_cachep, tb); |
594 | if (bhash2_created) |
595 | inet_bind2_bucket_destroy(cachep: hinfo->bind2_bucket_cachep, |
596 | tb: tb2); |
597 | } |
598 | if (head2_lock_acquired) |
599 | spin_unlock(lock: &head2->lock); |
600 | spin_unlock_bh(lock: &head->lock); |
601 | return ret; |
602 | } |
603 | EXPORT_SYMBOL_GPL(inet_csk_get_port); |
604 | |
605 | /* |
606 | * Wait for an incoming connection, avoid race conditions. This must be called |
607 | * with the socket locked. |
608 | */ |
609 | static int inet_csk_wait_for_connect(struct sock *sk, long timeo) |
610 | { |
611 | struct inet_connection_sock *icsk = inet_csk(sk); |
612 | DEFINE_WAIT(wait); |
613 | int err; |
614 | |
615 | /* |
616 | * True wake-one mechanism for incoming connections: only |
617 | * one process gets woken up, not the 'whole herd'. |
618 | * Since we do not 'race & poll' for established sockets |
619 | * anymore, the common case will execute the loop only once. |
620 | * |
621 | * Subtle issue: "add_wait_queue_exclusive()" will be added |
622 | * after any current non-exclusive waiters, and we know that |
623 | * it will always _stay_ after any new non-exclusive waiters |
624 | * because all non-exclusive waiters are added at the |
625 | * beginning of the wait-queue. As such, it's ok to "drop" |
626 | * our exclusiveness temporarily when we get woken up without |
627 | * having to remove and re-insert us on the wait queue. |
628 | */ |
629 | for (;;) { |
630 | prepare_to_wait_exclusive(wq_head: sk_sleep(sk), wq_entry: &wait, |
631 | TASK_INTERRUPTIBLE); |
632 | release_sock(sk); |
633 | if (reqsk_queue_empty(queue: &icsk->icsk_accept_queue)) |
634 | timeo = schedule_timeout(timeout: timeo); |
635 | sched_annotate_sleep(); |
636 | lock_sock(sk); |
637 | err = 0; |
638 | if (!reqsk_queue_empty(queue: &icsk->icsk_accept_queue)) |
639 | break; |
640 | err = -EINVAL; |
641 | if (sk->sk_state != TCP_LISTEN) |
642 | break; |
643 | err = sock_intr_errno(timeo); |
644 | if (signal_pending(current)) |
645 | break; |
646 | err = -EAGAIN; |
647 | if (!timeo) |
648 | break; |
649 | } |
650 | finish_wait(wq_head: sk_sleep(sk), wq_entry: &wait); |
651 | return err; |
652 | } |
653 | |
654 | /* |
655 | * This will accept the next outstanding connection. |
656 | */ |
657 | struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern) |
658 | { |
659 | struct inet_connection_sock *icsk = inet_csk(sk); |
660 | struct request_sock_queue *queue = &icsk->icsk_accept_queue; |
661 | struct request_sock *req; |
662 | struct sock *newsk; |
663 | int error; |
664 | |
665 | lock_sock(sk); |
666 | |
667 | /* We need to make sure that this socket is listening, |
668 | * and that it has something pending. |
669 | */ |
670 | error = -EINVAL; |
671 | if (sk->sk_state != TCP_LISTEN) |
672 | goto out_err; |
673 | |
674 | /* Find already established connection */ |
675 | if (reqsk_queue_empty(queue)) { |
676 | long timeo = sock_rcvtimeo(sk, noblock: flags & O_NONBLOCK); |
677 | |
678 | /* If this is a non blocking socket don't sleep */ |
679 | error = -EAGAIN; |
680 | if (!timeo) |
681 | goto out_err; |
682 | |
683 | error = inet_csk_wait_for_connect(sk, timeo); |
684 | if (error) |
685 | goto out_err; |
686 | } |
687 | req = reqsk_queue_remove(queue, parent: sk); |
688 | newsk = req->sk; |
689 | |
690 | if (sk->sk_protocol == IPPROTO_TCP && |
691 | tcp_rsk(req)->tfo_listener) { |
692 | spin_lock_bh(lock: &queue->fastopenq.lock); |
693 | if (tcp_rsk(req)->tfo_listener) { |
694 | /* We are still waiting for the final ACK from 3WHS |
695 | * so can't free req now. Instead, we set req->sk to |
696 | * NULL to signify that the child socket is taken |
697 | * so reqsk_fastopen_remove() will free the req |
698 | * when 3WHS finishes (or is aborted). |
699 | */ |
700 | req->sk = NULL; |
701 | req = NULL; |
702 | } |
703 | spin_unlock_bh(lock: &queue->fastopenq.lock); |
704 | } |
705 | |
706 | out: |
707 | release_sock(sk); |
708 | if (newsk && mem_cgroup_sockets_enabled) { |
709 | int amt = 0; |
710 | |
711 | /* atomically get the memory usage, set and charge the |
712 | * newsk->sk_memcg. |
713 | */ |
714 | lock_sock(sk: newsk); |
715 | |
716 | mem_cgroup_sk_alloc(sk: newsk); |
717 | if (newsk->sk_memcg) { |
718 | /* The socket has not been accepted yet, no need |
719 | * to look at newsk->sk_wmem_queued. |
720 | */ |
721 | amt = sk_mem_pages(amt: newsk->sk_forward_alloc + |
722 | atomic_read(v: &newsk->sk_rmem_alloc)); |
723 | } |
724 | |
725 | if (amt) |
726 | mem_cgroup_charge_skmem(memcg: newsk->sk_memcg, nr_pages: amt, |
727 | GFP_KERNEL | __GFP_NOFAIL); |
728 | |
729 | release_sock(sk: newsk); |
730 | } |
731 | if (req) |
732 | reqsk_put(req); |
733 | return newsk; |
734 | out_err: |
735 | newsk = NULL; |
736 | req = NULL; |
737 | *err = error; |
738 | goto out; |
739 | } |
740 | EXPORT_SYMBOL(inet_csk_accept); |
741 | |
742 | /* |
743 | * Using different timers for retransmit, delayed acks and probes |
744 | * We may wish use just one timer maintaining a list of expire jiffies |
745 | * to optimize. |
746 | */ |
747 | void inet_csk_init_xmit_timers(struct sock *sk, |
748 | void (*retransmit_handler)(struct timer_list *t), |
749 | void (*delack_handler)(struct timer_list *t), |
750 | void (*keepalive_handler)(struct timer_list *t)) |
751 | { |
752 | struct inet_connection_sock *icsk = inet_csk(sk); |
753 | |
754 | timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0); |
755 | timer_setup(&icsk->icsk_delack_timer, delack_handler, 0); |
756 | timer_setup(&sk->sk_timer, keepalive_handler, 0); |
757 | icsk->icsk_pending = icsk->icsk_ack.pending = 0; |
758 | } |
759 | EXPORT_SYMBOL(inet_csk_init_xmit_timers); |
760 | |
761 | void inet_csk_clear_xmit_timers(struct sock *sk) |
762 | { |
763 | struct inet_connection_sock *icsk = inet_csk(sk); |
764 | |
765 | icsk->icsk_pending = icsk->icsk_ack.pending = 0; |
766 | |
767 | sk_stop_timer(sk, timer: &icsk->icsk_retransmit_timer); |
768 | sk_stop_timer(sk, timer: &icsk->icsk_delack_timer); |
769 | sk_stop_timer(sk, timer: &sk->sk_timer); |
770 | } |
771 | EXPORT_SYMBOL(inet_csk_clear_xmit_timers); |
772 | |
773 | void inet_csk_delete_keepalive_timer(struct sock *sk) |
774 | { |
775 | sk_stop_timer(sk, timer: &sk->sk_timer); |
776 | } |
777 | EXPORT_SYMBOL(inet_csk_delete_keepalive_timer); |
778 | |
779 | void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len) |
780 | { |
781 | sk_reset_timer(sk, timer: &sk->sk_timer, expires: jiffies + len); |
782 | } |
783 | EXPORT_SYMBOL(inet_csk_reset_keepalive_timer); |
784 | |
785 | struct dst_entry *inet_csk_route_req(const struct sock *sk, |
786 | struct flowi4 *fl4, |
787 | const struct request_sock *req) |
788 | { |
789 | const struct inet_request_sock *ireq = inet_rsk(sk: req); |
790 | struct net *net = read_pnet(pnet: &ireq->ireq_net); |
791 | struct ip_options_rcu *opt; |
792 | struct rtable *rt; |
793 | |
794 | rcu_read_lock(); |
795 | opt = rcu_dereference(ireq->ireq_opt); |
796 | |
797 | flowi4_init_output(fl4, oif: ireq->ir_iif, mark: ireq->ir_mark, |
798 | tos: ip_sock_rt_tos(sk), scope: ip_sock_rt_scope(sk), |
799 | proto: sk->sk_protocol, flags: inet_sk_flowi_flags(sk), |
800 | daddr: (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr, |
801 | saddr: ireq->ir_loc_addr, dport: ireq->ir_rmt_port, |
802 | htons(ireq->ir_num), uid: sk->sk_uid); |
803 | security_req_classify_flow(req, flic: flowi4_to_flowi_common(fl4)); |
804 | rt = ip_route_output_flow(net, flp: fl4, sk); |
805 | if (IS_ERR(ptr: rt)) |
806 | goto no_route; |
807 | if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) |
808 | goto route_err; |
809 | rcu_read_unlock(); |
810 | return &rt->dst; |
811 | |
812 | route_err: |
813 | ip_rt_put(rt); |
814 | no_route: |
815 | rcu_read_unlock(); |
816 | __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); |
817 | return NULL; |
818 | } |
819 | EXPORT_SYMBOL_GPL(inet_csk_route_req); |
820 | |
821 | struct dst_entry *inet_csk_route_child_sock(const struct sock *sk, |
822 | struct sock *newsk, |
823 | const struct request_sock *req) |
824 | { |
825 | const struct inet_request_sock *ireq = inet_rsk(sk: req); |
826 | struct net *net = read_pnet(pnet: &ireq->ireq_net); |
827 | struct inet_sock *newinet = inet_sk(newsk); |
828 | struct ip_options_rcu *opt; |
829 | struct flowi4 *fl4; |
830 | struct rtable *rt; |
831 | |
832 | opt = rcu_dereference(ireq->ireq_opt); |
833 | fl4 = &newinet->cork.fl.u.ip4; |
834 | |
835 | flowi4_init_output(fl4, oif: ireq->ir_iif, mark: ireq->ir_mark, |
836 | tos: ip_sock_rt_tos(sk), scope: ip_sock_rt_scope(sk), |
837 | proto: sk->sk_protocol, flags: inet_sk_flowi_flags(sk), |
838 | daddr: (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr, |
839 | saddr: ireq->ir_loc_addr, dport: ireq->ir_rmt_port, |
840 | htons(ireq->ir_num), uid: sk->sk_uid); |
841 | security_req_classify_flow(req, flic: flowi4_to_flowi_common(fl4)); |
842 | rt = ip_route_output_flow(net, flp: fl4, sk); |
843 | if (IS_ERR(ptr: rt)) |
844 | goto no_route; |
845 | if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) |
846 | goto route_err; |
847 | return &rt->dst; |
848 | |
849 | route_err: |
850 | ip_rt_put(rt); |
851 | no_route: |
852 | __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); |
853 | return NULL; |
854 | } |
855 | EXPORT_SYMBOL_GPL(inet_csk_route_child_sock); |
856 | |
857 | /* Decide when to expire the request and when to resend SYN-ACK */ |
858 | static void syn_ack_recalc(struct request_sock *req, |
859 | const int max_syn_ack_retries, |
860 | const u8 rskq_defer_accept, |
861 | int *expire, int *resend) |
862 | { |
863 | if (!rskq_defer_accept) { |
864 | *expire = req->num_timeout >= max_syn_ack_retries; |
865 | *resend = 1; |
866 | return; |
867 | } |
868 | *expire = req->num_timeout >= max_syn_ack_retries && |
869 | (!inet_rsk(sk: req)->acked || req->num_timeout >= rskq_defer_accept); |
870 | /* Do not resend while waiting for data after ACK, |
871 | * start to resend on end of deferring period to give |
872 | * last chance for data or ACK to create established socket. |
873 | */ |
874 | *resend = !inet_rsk(sk: req)->acked || |
875 | req->num_timeout >= rskq_defer_accept - 1; |
876 | } |
877 | |
878 | int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req) |
879 | { |
880 | int err = req->rsk_ops->rtx_syn_ack(parent, req); |
881 | |
882 | if (!err) |
883 | req->num_retrans++; |
884 | return err; |
885 | } |
886 | EXPORT_SYMBOL(inet_rtx_syn_ack); |
887 | |
888 | static struct request_sock *inet_reqsk_clone(struct request_sock *req, |
889 | struct sock *sk) |
890 | { |
891 | struct sock *req_sk, *nreq_sk; |
892 | struct request_sock *nreq; |
893 | |
894 | nreq = kmem_cache_alloc(cachep: req->rsk_ops->slab, GFP_ATOMIC | __GFP_NOWARN); |
895 | if (!nreq) { |
896 | __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE); |
897 | |
898 | /* paired with refcount_inc_not_zero() in reuseport_migrate_sock() */ |
899 | sock_put(sk); |
900 | return NULL; |
901 | } |
902 | |
903 | req_sk = req_to_sk(req); |
904 | nreq_sk = req_to_sk(req: nreq); |
905 | |
906 | memcpy(nreq_sk, req_sk, |
907 | offsetof(struct sock, sk_dontcopy_begin)); |
908 | memcpy(&nreq_sk->sk_dontcopy_end, &req_sk->sk_dontcopy_end, |
909 | req->rsk_ops->obj_size - offsetof(struct sock, sk_dontcopy_end)); |
910 | |
911 | sk_node_init(node: &nreq_sk->sk_node); |
912 | nreq_sk->sk_tx_queue_mapping = req_sk->sk_tx_queue_mapping; |
913 | #ifdef CONFIG_SOCK_RX_QUEUE_MAPPING |
914 | nreq_sk->sk_rx_queue_mapping = req_sk->sk_rx_queue_mapping; |
915 | #endif |
916 | nreq_sk->sk_incoming_cpu = req_sk->sk_incoming_cpu; |
917 | |
918 | nreq->rsk_listener = sk; |
919 | |
920 | /* We need not acquire fastopenq->lock |
921 | * because the child socket is locked in inet_csk_listen_stop(). |
922 | */ |
923 | if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req: nreq)->tfo_listener) |
924 | rcu_assign_pointer(tcp_sk(nreq->sk)->fastopen_rsk, nreq); |
925 | |
926 | return nreq; |
927 | } |
928 | |
929 | static void reqsk_queue_migrated(struct request_sock_queue *queue, |
930 | const struct request_sock *req) |
931 | { |
932 | if (req->num_timeout == 0) |
933 | atomic_inc(v: &queue->young); |
934 | atomic_inc(v: &queue->qlen); |
935 | } |
936 | |
937 | static void reqsk_migrate_reset(struct request_sock *req) |
938 | { |
939 | req->saved_syn = NULL; |
940 | #if IS_ENABLED(CONFIG_IPV6) |
941 | inet_rsk(sk: req)->ipv6_opt = NULL; |
942 | inet_rsk(sk: req)->pktopts = NULL; |
943 | #else |
944 | inet_rsk(req)->ireq_opt = NULL; |
945 | #endif |
946 | } |
947 | |
948 | /* return true if req was found in the ehash table */ |
949 | static bool reqsk_queue_unlink(struct request_sock *req) |
950 | { |
951 | struct sock *sk = req_to_sk(req); |
952 | bool found = false; |
953 | |
954 | if (sk_hashed(sk)) { |
955 | struct inet_hashinfo *hashinfo = tcp_or_dccp_get_hashinfo(sk); |
956 | spinlock_t *lock = inet_ehash_lockp(hashinfo, hash: req->rsk_hash); |
957 | |
958 | spin_lock(lock); |
959 | found = __sk_nulls_del_node_init_rcu(sk); |
960 | spin_unlock(lock); |
961 | } |
962 | if (timer_pending(timer: &req->rsk_timer) && del_timer_sync(timer: &req->rsk_timer)) |
963 | reqsk_put(req); |
964 | return found; |
965 | } |
966 | |
967 | bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req) |
968 | { |
969 | bool unlinked = reqsk_queue_unlink(req); |
970 | |
971 | if (unlinked) { |
972 | reqsk_queue_removed(queue: &inet_csk(sk)->icsk_accept_queue, req); |
973 | reqsk_put(req); |
974 | } |
975 | return unlinked; |
976 | } |
977 | EXPORT_SYMBOL(inet_csk_reqsk_queue_drop); |
978 | |
979 | void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req) |
980 | { |
981 | inet_csk_reqsk_queue_drop(sk, req); |
982 | reqsk_put(req); |
983 | } |
984 | EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put); |
985 | |
986 | static void reqsk_timer_handler(struct timer_list *t) |
987 | { |
988 | struct request_sock *req = from_timer(req, t, rsk_timer); |
989 | struct request_sock *nreq = NULL, *oreq = req; |
990 | struct sock *sk_listener = req->rsk_listener; |
991 | struct inet_connection_sock *icsk; |
992 | struct request_sock_queue *queue; |
993 | struct net *net; |
994 | int max_syn_ack_retries, qlen, expire = 0, resend = 0; |
995 | |
996 | if (inet_sk_state_load(sk: sk_listener) != TCP_LISTEN) { |
997 | struct sock *nsk; |
998 | |
999 | nsk = reuseport_migrate_sock(sk: sk_listener, migrating_sk: req_to_sk(req), NULL); |
1000 | if (!nsk) |
1001 | goto drop; |
1002 | |
1003 | nreq = inet_reqsk_clone(req, sk: nsk); |
1004 | if (!nreq) |
1005 | goto drop; |
1006 | |
1007 | /* The new timer for the cloned req can decrease the 2 |
1008 | * by calling inet_csk_reqsk_queue_drop_and_put(), so |
1009 | * hold another count to prevent use-after-free and |
1010 | * call reqsk_put() just before return. |
1011 | */ |
1012 | refcount_set(r: &nreq->rsk_refcnt, n: 2 + 1); |
1013 | timer_setup(&nreq->rsk_timer, reqsk_timer_handler, TIMER_PINNED); |
1014 | reqsk_queue_migrated(queue: &inet_csk(sk: nsk)->icsk_accept_queue, req); |
1015 | |
1016 | req = nreq; |
1017 | sk_listener = nsk; |
1018 | } |
1019 | |
1020 | icsk = inet_csk(sk: sk_listener); |
1021 | net = sock_net(sk: sk_listener); |
1022 | max_syn_ack_retries = READ_ONCE(icsk->icsk_syn_retries) ? : |
1023 | READ_ONCE(net->ipv4.sysctl_tcp_synack_retries); |
1024 | /* Normally all the openreqs are young and become mature |
1025 | * (i.e. converted to established socket) for first timeout. |
1026 | * If synack was not acknowledged for 1 second, it means |
1027 | * one of the following things: synack was lost, ack was lost, |
1028 | * rtt is high or nobody planned to ack (i.e. synflood). |
1029 | * When server is a bit loaded, queue is populated with old |
1030 | * open requests, reducing effective size of queue. |
1031 | * When server is well loaded, queue size reduces to zero |
1032 | * after several minutes of work. It is not synflood, |
1033 | * it is normal operation. The solution is pruning |
1034 | * too old entries overriding normal timeout, when |
1035 | * situation becomes dangerous. |
1036 | * |
1037 | * Essentially, we reserve half of room for young |
1038 | * embrions; and abort old ones without pity, if old |
1039 | * ones are about to clog our table. |
1040 | */ |
1041 | queue = &icsk->icsk_accept_queue; |
1042 | qlen = reqsk_queue_len(queue); |
1043 | if ((qlen << 1) > max(8U, READ_ONCE(sk_listener->sk_max_ack_backlog))) { |
1044 | int young = reqsk_queue_len_young(queue) << 1; |
1045 | |
1046 | while (max_syn_ack_retries > 2) { |
1047 | if (qlen < young) |
1048 | break; |
1049 | max_syn_ack_retries--; |
1050 | young <<= 1; |
1051 | } |
1052 | } |
1053 | syn_ack_recalc(req, max_syn_ack_retries, READ_ONCE(queue->rskq_defer_accept), |
1054 | expire: &expire, resend: &resend); |
1055 | req->rsk_ops->syn_ack_timeout(req); |
1056 | if (!expire && |
1057 | (!resend || |
1058 | !inet_rtx_syn_ack(sk_listener, req) || |
1059 | inet_rsk(sk: req)->acked)) { |
1060 | if (req->num_timeout++ == 0) |
1061 | atomic_dec(v: &queue->young); |
1062 | mod_timer(timer: &req->rsk_timer, expires: jiffies + reqsk_timeout(req, TCP_RTO_MAX)); |
1063 | |
1064 | if (!nreq) |
1065 | return; |
1066 | |
1067 | if (!inet_ehash_insert(sk: req_to_sk(req: nreq), osk: req_to_sk(req: oreq), NULL)) { |
1068 | /* delete timer */ |
1069 | inet_csk_reqsk_queue_drop(sk_listener, nreq); |
1070 | goto no_ownership; |
1071 | } |
1072 | |
1073 | __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQSUCCESS); |
1074 | reqsk_migrate_reset(req: oreq); |
1075 | reqsk_queue_removed(queue: &inet_csk(sk: oreq->rsk_listener)->icsk_accept_queue, req: oreq); |
1076 | reqsk_put(req: oreq); |
1077 | |
1078 | reqsk_put(req: nreq); |
1079 | return; |
1080 | } |
1081 | |
1082 | /* Even if we can clone the req, we may need not retransmit any more |
1083 | * SYN+ACKs (nreq->num_timeout > max_syn_ack_retries, etc), or another |
1084 | * CPU may win the "own_req" race so that inet_ehash_insert() fails. |
1085 | */ |
1086 | if (nreq) { |
1087 | __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQFAILURE); |
1088 | no_ownership: |
1089 | reqsk_migrate_reset(req: nreq); |
1090 | reqsk_queue_removed(queue, req: nreq); |
1091 | __reqsk_free(req: nreq); |
1092 | } |
1093 | |
1094 | drop: |
1095 | inet_csk_reqsk_queue_drop_and_put(oreq->rsk_listener, oreq); |
1096 | } |
1097 | |
1098 | static void reqsk_queue_hash_req(struct request_sock *req, |
1099 | unsigned long timeout) |
1100 | { |
1101 | timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED); |
1102 | mod_timer(timer: &req->rsk_timer, expires: jiffies + timeout); |
1103 | |
1104 | inet_ehash_insert(sk: req_to_sk(req), NULL, NULL); |
1105 | /* before letting lookups find us, make sure all req fields |
1106 | * are committed to memory and refcnt initialized. |
1107 | */ |
1108 | smp_wmb(); |
1109 | refcount_set(r: &req->rsk_refcnt, n: 2 + 1); |
1110 | } |
1111 | |
1112 | void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req, |
1113 | unsigned long timeout) |
1114 | { |
1115 | reqsk_queue_hash_req(req, timeout); |
1116 | inet_csk_reqsk_queue_added(sk); |
1117 | } |
1118 | EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add); |
1119 | |
1120 | static void inet_clone_ulp(const struct request_sock *req, struct sock *newsk, |
1121 | const gfp_t priority) |
1122 | { |
1123 | struct inet_connection_sock *icsk = inet_csk(sk: newsk); |
1124 | |
1125 | if (!icsk->icsk_ulp_ops) |
1126 | return; |
1127 | |
1128 | icsk->icsk_ulp_ops->clone(req, newsk, priority); |
1129 | } |
1130 | |
1131 | /** |
1132 | * inet_csk_clone_lock - clone an inet socket, and lock its clone |
1133 | * @sk: the socket to clone |
1134 | * @req: request_sock |
1135 | * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc) |
1136 | * |
1137 | * Caller must unlock socket even in error path (bh_unlock_sock(newsk)) |
1138 | */ |
1139 | struct sock *inet_csk_clone_lock(const struct sock *sk, |
1140 | const struct request_sock *req, |
1141 | const gfp_t priority) |
1142 | { |
1143 | struct sock *newsk = sk_clone_lock(sk, priority); |
1144 | |
1145 | if (newsk) { |
1146 | struct inet_connection_sock *newicsk = inet_csk(sk: newsk); |
1147 | |
1148 | inet_sk_set_state(sk: newsk, state: TCP_SYN_RECV); |
1149 | newicsk->icsk_bind_hash = NULL; |
1150 | newicsk->icsk_bind2_hash = NULL; |
1151 | |
1152 | inet_sk(newsk)->inet_dport = inet_rsk(sk: req)->ir_rmt_port; |
1153 | inet_sk(newsk)->inet_num = inet_rsk(sk: req)->ir_num; |
1154 | inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num); |
1155 | |
1156 | /* listeners have SOCK_RCU_FREE, not the children */ |
1157 | sock_reset_flag(sk: newsk, flag: SOCK_RCU_FREE); |
1158 | |
1159 | inet_sk(newsk)->mc_list = NULL; |
1160 | |
1161 | newsk->sk_mark = inet_rsk(sk: req)->ir_mark; |
1162 | atomic64_set(v: &newsk->sk_cookie, |
1163 | i: atomic64_read(v: &inet_rsk(sk: req)->ir_cookie)); |
1164 | |
1165 | newicsk->icsk_retransmits = 0; |
1166 | newicsk->icsk_backoff = 0; |
1167 | newicsk->icsk_probes_out = 0; |
1168 | newicsk->icsk_probes_tstamp = 0; |
1169 | |
1170 | /* Deinitialize accept_queue to trap illegal accesses. */ |
1171 | memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue)); |
1172 | |
1173 | inet_clone_ulp(req, newsk, priority); |
1174 | |
1175 | security_inet_csk_clone(newsk, req); |
1176 | } |
1177 | return newsk; |
1178 | } |
1179 | EXPORT_SYMBOL_GPL(inet_csk_clone_lock); |
1180 | |
1181 | /* |
1182 | * At this point, there should be no process reference to this |
1183 | * socket, and thus no user references at all. Therefore we |
1184 | * can assume the socket waitqueue is inactive and nobody will |
1185 | * try to jump onto it. |
1186 | */ |
1187 | void inet_csk_destroy_sock(struct sock *sk) |
1188 | { |
1189 | WARN_ON(sk->sk_state != TCP_CLOSE); |
1190 | WARN_ON(!sock_flag(sk, SOCK_DEAD)); |
1191 | |
1192 | /* It cannot be in hash table! */ |
1193 | WARN_ON(!sk_unhashed(sk)); |
1194 | |
1195 | /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */ |
1196 | WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash); |
1197 | |
1198 | sk->sk_prot->destroy(sk); |
1199 | |
1200 | sk_stream_kill_queues(sk); |
1201 | |
1202 | xfrm_sk_free_policy(sk); |
1203 | |
1204 | this_cpu_dec(*sk->sk_prot->orphan_count); |
1205 | |
1206 | sock_put(sk); |
1207 | } |
1208 | EXPORT_SYMBOL(inet_csk_destroy_sock); |
1209 | |
1210 | /* This function allows to force a closure of a socket after the call to |
1211 | * tcp/dccp_create_openreq_child(). |
1212 | */ |
1213 | void inet_csk_prepare_forced_close(struct sock *sk) |
1214 | __releases(&sk->sk_lock.slock) |
1215 | { |
1216 | /* sk_clone_lock locked the socket and set refcnt to 2 */ |
1217 | bh_unlock_sock(sk); |
1218 | sock_put(sk); |
1219 | inet_csk_prepare_for_destroy_sock(sk); |
1220 | inet_sk(sk)->inet_num = 0; |
1221 | } |
1222 | EXPORT_SYMBOL(inet_csk_prepare_forced_close); |
1223 | |
1224 | static int inet_ulp_can_listen(const struct sock *sk) |
1225 | { |
1226 | const struct inet_connection_sock *icsk = inet_csk(sk); |
1227 | |
1228 | if (icsk->icsk_ulp_ops && !icsk->icsk_ulp_ops->clone) |
1229 | return -EINVAL; |
1230 | |
1231 | return 0; |
1232 | } |
1233 | |
1234 | int inet_csk_listen_start(struct sock *sk) |
1235 | { |
1236 | struct inet_connection_sock *icsk = inet_csk(sk); |
1237 | struct inet_sock *inet = inet_sk(sk); |
1238 | int err; |
1239 | |
1240 | err = inet_ulp_can_listen(sk); |
1241 | if (unlikely(err)) |
1242 | return err; |
1243 | |
1244 | reqsk_queue_alloc(queue: &icsk->icsk_accept_queue); |
1245 | |
1246 | sk->sk_ack_backlog = 0; |
1247 | inet_csk_delack_init(sk); |
1248 | |
1249 | /* There is race window here: we announce ourselves listening, |
1250 | * but this transition is still not validated by get_port(). |
1251 | * It is OK, because this socket enters to hash table only |
1252 | * after validation is complete. |
1253 | */ |
1254 | inet_sk_state_store(sk, newstate: TCP_LISTEN); |
1255 | err = sk->sk_prot->get_port(sk, inet->inet_num); |
1256 | if (!err) { |
1257 | inet->inet_sport = htons(inet->inet_num); |
1258 | |
1259 | sk_dst_reset(sk); |
1260 | err = sk->sk_prot->hash(sk); |
1261 | |
1262 | if (likely(!err)) |
1263 | return 0; |
1264 | } |
1265 | |
1266 | inet_sk_set_state(sk, state: TCP_CLOSE); |
1267 | return err; |
1268 | } |
1269 | EXPORT_SYMBOL_GPL(inet_csk_listen_start); |
1270 | |
1271 | static void inet_child_forget(struct sock *sk, struct request_sock *req, |
1272 | struct sock *child) |
1273 | { |
1274 | sk->sk_prot->disconnect(child, O_NONBLOCK); |
1275 | |
1276 | sock_orphan(sk: child); |
1277 | |
1278 | this_cpu_inc(*sk->sk_prot->orphan_count); |
1279 | |
1280 | if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) { |
1281 | BUG_ON(rcu_access_pointer(tcp_sk(child)->fastopen_rsk) != req); |
1282 | BUG_ON(sk != req->rsk_listener); |
1283 | |
1284 | /* Paranoid, to prevent race condition if |
1285 | * an inbound pkt destined for child is |
1286 | * blocked by sock lock in tcp_v4_rcv(). |
1287 | * Also to satisfy an assertion in |
1288 | * tcp_v4_destroy_sock(). |
1289 | */ |
1290 | RCU_INIT_POINTER(tcp_sk(child)->fastopen_rsk, NULL); |
1291 | } |
1292 | inet_csk_destroy_sock(child); |
1293 | } |
1294 | |
1295 | struct sock *inet_csk_reqsk_queue_add(struct sock *sk, |
1296 | struct request_sock *req, |
1297 | struct sock *child) |
1298 | { |
1299 | struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue; |
1300 | |
1301 | spin_lock(lock: &queue->rskq_lock); |
1302 | if (unlikely(sk->sk_state != TCP_LISTEN)) { |
1303 | inet_child_forget(sk, req, child); |
1304 | child = NULL; |
1305 | } else { |
1306 | req->sk = child; |
1307 | req->dl_next = NULL; |
1308 | if (queue->rskq_accept_head == NULL) |
1309 | WRITE_ONCE(queue->rskq_accept_head, req); |
1310 | else |
1311 | queue->rskq_accept_tail->dl_next = req; |
1312 | queue->rskq_accept_tail = req; |
1313 | sk_acceptq_added(sk); |
1314 | } |
1315 | spin_unlock(lock: &queue->rskq_lock); |
1316 | return child; |
1317 | } |
1318 | EXPORT_SYMBOL(inet_csk_reqsk_queue_add); |
1319 | |
1320 | struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child, |
1321 | struct request_sock *req, bool own_req) |
1322 | { |
1323 | if (own_req) { |
1324 | inet_csk_reqsk_queue_drop(req->rsk_listener, req); |
1325 | reqsk_queue_removed(queue: &inet_csk(sk: req->rsk_listener)->icsk_accept_queue, req); |
1326 | |
1327 | if (sk != req->rsk_listener) { |
1328 | /* another listening sk has been selected, |
1329 | * migrate the req to it. |
1330 | */ |
1331 | struct request_sock *nreq; |
1332 | |
1333 | /* hold a refcnt for the nreq->rsk_listener |
1334 | * which is assigned in inet_reqsk_clone() |
1335 | */ |
1336 | sock_hold(sk); |
1337 | nreq = inet_reqsk_clone(req, sk); |
1338 | if (!nreq) { |
1339 | inet_child_forget(sk, req, child); |
1340 | goto child_put; |
1341 | } |
1342 | |
1343 | refcount_set(r: &nreq->rsk_refcnt, n: 1); |
1344 | if (inet_csk_reqsk_queue_add(sk, nreq, child)) { |
1345 | __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQSUCCESS); |
1346 | reqsk_migrate_reset(req); |
1347 | reqsk_put(req); |
1348 | return child; |
1349 | } |
1350 | |
1351 | __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE); |
1352 | reqsk_migrate_reset(req: nreq); |
1353 | __reqsk_free(req: nreq); |
1354 | } else if (inet_csk_reqsk_queue_add(sk, req, child)) { |
1355 | return child; |
1356 | } |
1357 | } |
1358 | /* Too bad, another child took ownership of the request, undo. */ |
1359 | child_put: |
1360 | bh_unlock_sock(child); |
1361 | sock_put(sk: child); |
1362 | return NULL; |
1363 | } |
1364 | EXPORT_SYMBOL(inet_csk_complete_hashdance); |
1365 | |
1366 | /* |
1367 | * This routine closes sockets which have been at least partially |
1368 | * opened, but not yet accepted. |
1369 | */ |
1370 | void inet_csk_listen_stop(struct sock *sk) |
1371 | { |
1372 | struct inet_connection_sock *icsk = inet_csk(sk); |
1373 | struct request_sock_queue *queue = &icsk->icsk_accept_queue; |
1374 | struct request_sock *next, *req; |
1375 | |
1376 | /* Following specs, it would be better either to send FIN |
1377 | * (and enter FIN-WAIT-1, it is normal close) |
1378 | * or to send active reset (abort). |
1379 | * Certainly, it is pretty dangerous while synflood, but it is |
1380 | * bad justification for our negligence 8) |
1381 | * To be honest, we are not able to make either |
1382 | * of the variants now. --ANK |
1383 | */ |
1384 | while ((req = reqsk_queue_remove(queue, parent: sk)) != NULL) { |
1385 | struct sock *child = req->sk, *nsk; |
1386 | struct request_sock *nreq; |
1387 | |
1388 | local_bh_disable(); |
1389 | bh_lock_sock(child); |
1390 | WARN_ON(sock_owned_by_user(child)); |
1391 | sock_hold(sk: child); |
1392 | |
1393 | nsk = reuseport_migrate_sock(sk, migrating_sk: child, NULL); |
1394 | if (nsk) { |
1395 | nreq = inet_reqsk_clone(req, sk: nsk); |
1396 | if (nreq) { |
1397 | refcount_set(r: &nreq->rsk_refcnt, n: 1); |
1398 | |
1399 | if (inet_csk_reqsk_queue_add(nsk, nreq, child)) { |
1400 | __NET_INC_STATS(sock_net(nsk), |
1401 | LINUX_MIB_TCPMIGRATEREQSUCCESS); |
1402 | reqsk_migrate_reset(req); |
1403 | } else { |
1404 | __NET_INC_STATS(sock_net(nsk), |
1405 | LINUX_MIB_TCPMIGRATEREQFAILURE); |
1406 | reqsk_migrate_reset(req: nreq); |
1407 | __reqsk_free(req: nreq); |
1408 | } |
1409 | |
1410 | /* inet_csk_reqsk_queue_add() has already |
1411 | * called inet_child_forget() on failure case. |
1412 | */ |
1413 | goto skip_child_forget; |
1414 | } |
1415 | } |
1416 | |
1417 | inet_child_forget(sk, req, child); |
1418 | skip_child_forget: |
1419 | reqsk_put(req); |
1420 | bh_unlock_sock(child); |
1421 | local_bh_enable(); |
1422 | sock_put(sk: child); |
1423 | |
1424 | cond_resched(); |
1425 | } |
1426 | if (queue->fastopenq.rskq_rst_head) { |
1427 | /* Free all the reqs queued in rskq_rst_head. */ |
1428 | spin_lock_bh(lock: &queue->fastopenq.lock); |
1429 | req = queue->fastopenq.rskq_rst_head; |
1430 | queue->fastopenq.rskq_rst_head = NULL; |
1431 | spin_unlock_bh(lock: &queue->fastopenq.lock); |
1432 | while (req != NULL) { |
1433 | next = req->dl_next; |
1434 | reqsk_put(req); |
1435 | req = next; |
1436 | } |
1437 | } |
1438 | WARN_ON_ONCE(sk->sk_ack_backlog); |
1439 | } |
1440 | EXPORT_SYMBOL_GPL(inet_csk_listen_stop); |
1441 | |
1442 | void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr) |
1443 | { |
1444 | struct sockaddr_in *sin = (struct sockaddr_in *)uaddr; |
1445 | const struct inet_sock *inet = inet_sk(sk); |
1446 | |
1447 | sin->sin_family = AF_INET; |
1448 | sin->sin_addr.s_addr = inet->inet_daddr; |
1449 | sin->sin_port = inet->inet_dport; |
1450 | } |
1451 | EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr); |
1452 | |
1453 | static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl) |
1454 | { |
1455 | const struct inet_sock *inet = inet_sk(sk); |
1456 | const struct ip_options_rcu *inet_opt; |
1457 | __be32 daddr = inet->inet_daddr; |
1458 | struct flowi4 *fl4; |
1459 | struct rtable *rt; |
1460 | |
1461 | rcu_read_lock(); |
1462 | inet_opt = rcu_dereference(inet->inet_opt); |
1463 | if (inet_opt && inet_opt->opt.srr) |
1464 | daddr = inet_opt->opt.faddr; |
1465 | fl4 = &fl->u.ip4; |
1466 | rt = ip_route_output_ports(net: sock_net(sk), fl4, sk, daddr, |
1467 | saddr: inet->inet_saddr, dport: inet->inet_dport, |
1468 | sport: inet->inet_sport, proto: sk->sk_protocol, |
1469 | RT_CONN_FLAGS(sk), oif: sk->sk_bound_dev_if); |
1470 | if (IS_ERR(ptr: rt)) |
1471 | rt = NULL; |
1472 | if (rt) |
1473 | sk_setup_caps(sk, dst: &rt->dst); |
1474 | rcu_read_unlock(); |
1475 | |
1476 | return &rt->dst; |
1477 | } |
1478 | |
1479 | struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu) |
1480 | { |
1481 | struct dst_entry *dst = __sk_dst_check(sk, cookie: 0); |
1482 | struct inet_sock *inet = inet_sk(sk); |
1483 | |
1484 | if (!dst) { |
1485 | dst = inet_csk_rebuild_route(sk, fl: &inet->cork.fl); |
1486 | if (!dst) |
1487 | goto out; |
1488 | } |
1489 | dst->ops->update_pmtu(dst, sk, NULL, mtu, true); |
1490 | |
1491 | dst = __sk_dst_check(sk, cookie: 0); |
1492 | if (!dst) |
1493 | dst = inet_csk_rebuild_route(sk, fl: &inet->cork.fl); |
1494 | out: |
1495 | return dst; |
1496 | } |
1497 | EXPORT_SYMBOL_GPL(inet_csk_update_pmtu); |
1498 | |