xref: /linux/net/phonet/socket.c (revision fa84cf094ef9667e2b91c104b0a788fd1896f482)
1 /*
2  * File: socket.c
3  *
4  * Phonet sockets
5  *
6  * Copyright (C) 2008 Nokia Corporation.
7  *
8  * Authors: Sakari Ailus <sakari.ailus@nokia.com>
9  *          Rémi Denis-Courmont
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  * version 2 as published by the Free Software Foundation.
14  *
15  * This program is distributed in the hope that it will be useful, but
16  * WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
23  * 02110-1301 USA
24  */
25 
26 #include <linux/gfp.h>
27 #include <linux/kernel.h>
28 #include <linux/net.h>
29 #include <linux/poll.h>
30 #include <linux/sched/signal.h>
31 
32 #include <net/sock.h>
33 #include <net/tcp_states.h>
34 
35 #include <linux/phonet.h>
36 #include <linux/export.h>
37 #include <net/phonet/phonet.h>
38 #include <net/phonet/pep.h>
39 #include <net/phonet/pn_dev.h>
40 
41 static int pn_socket_release(struct socket *sock)
42 {
43 	struct sock *sk = sock->sk;
44 
45 	if (sk) {
46 		sock->sk = NULL;
47 		sk->sk_prot->close(sk, 0);
48 	}
49 	return 0;
50 }
51 
52 #define PN_HASHSIZE	16
53 #define PN_HASHMASK	(PN_HASHSIZE-1)
54 
55 
56 static struct  {
57 	struct hlist_head hlist[PN_HASHSIZE];
58 	struct mutex lock;
59 } pnsocks;
60 
61 void __init pn_sock_init(void)
62 {
63 	unsigned int i;
64 
65 	for (i = 0; i < PN_HASHSIZE; i++)
66 		INIT_HLIST_HEAD(pnsocks.hlist + i);
67 	mutex_init(&pnsocks.lock);
68 }
69 
70 static struct hlist_head *pn_hash_list(u16 obj)
71 {
72 	return pnsocks.hlist + (obj & PN_HASHMASK);
73 }
74 
75 /*
76  * Find address based on socket address, match only certain fields.
77  * Also grab sock if it was found. Remember to sock_put it later.
78  */
79 struct sock *pn_find_sock_by_sa(struct net *net, const struct sockaddr_pn *spn)
80 {
81 	struct sock *sknode;
82 	struct sock *rval = NULL;
83 	u16 obj = pn_sockaddr_get_object(spn);
84 	u8 res = spn->spn_resource;
85 	struct hlist_head *hlist = pn_hash_list(obj);
86 
87 	rcu_read_lock();
88 	sk_for_each_rcu(sknode, hlist) {
89 		struct pn_sock *pn = pn_sk(sknode);
90 		BUG_ON(!pn->sobject); /* unbound socket */
91 
92 		if (!net_eq(sock_net(sknode), net))
93 			continue;
94 		if (pn_port(obj)) {
95 			/* Look up socket by port */
96 			if (pn_port(pn->sobject) != pn_port(obj))
97 				continue;
98 		} else {
99 			/* If port is zero, look up by resource */
100 			if (pn->resource != res)
101 				continue;
102 		}
103 		if (pn_addr(pn->sobject) &&
104 		    pn_addr(pn->sobject) != pn_addr(obj))
105 			continue;
106 
107 		rval = sknode;
108 		sock_hold(sknode);
109 		break;
110 	}
111 	rcu_read_unlock();
112 
113 	return rval;
114 }
115 
116 /* Deliver a broadcast packet (only in bottom-half) */
117 void pn_deliver_sock_broadcast(struct net *net, struct sk_buff *skb)
118 {
119 	struct hlist_head *hlist = pnsocks.hlist;
120 	unsigned int h;
121 
122 	rcu_read_lock();
123 	for (h = 0; h < PN_HASHSIZE; h++) {
124 		struct sock *sknode;
125 
126 		sk_for_each(sknode, hlist) {
127 			struct sk_buff *clone;
128 
129 			if (!net_eq(sock_net(sknode), net))
130 				continue;
131 			if (!sock_flag(sknode, SOCK_BROADCAST))
132 				continue;
133 
134 			clone = skb_clone(skb, GFP_ATOMIC);
135 			if (clone) {
136 				sock_hold(sknode);
137 				sk_receive_skb(sknode, clone, 0);
138 			}
139 		}
140 		hlist++;
141 	}
142 	rcu_read_unlock();
143 }
144 
145 int pn_sock_hash(struct sock *sk)
146 {
147 	struct hlist_head *hlist = pn_hash_list(pn_sk(sk)->sobject);
148 
149 	mutex_lock(&pnsocks.lock);
150 	sk_add_node_rcu(sk, hlist);
151 	mutex_unlock(&pnsocks.lock);
152 
153 	return 0;
154 }
155 EXPORT_SYMBOL(pn_sock_hash);
156 
157 void pn_sock_unhash(struct sock *sk)
158 {
159 	mutex_lock(&pnsocks.lock);
160 	sk_del_node_init_rcu(sk);
161 	mutex_unlock(&pnsocks.lock);
162 	pn_sock_unbind_all_res(sk);
163 	synchronize_rcu();
164 }
165 EXPORT_SYMBOL(pn_sock_unhash);
166 
167 static DEFINE_MUTEX(port_mutex);
168 
169 static int pn_socket_bind(struct socket *sock, struct sockaddr *addr, int len)
170 {
171 	struct sock *sk = sock->sk;
172 	struct pn_sock *pn = pn_sk(sk);
173 	struct sockaddr_pn *spn = (struct sockaddr_pn *)addr;
174 	int err;
175 	u16 handle;
176 	u8 saddr;
177 
178 	if (sk->sk_prot->bind)
179 		return sk->sk_prot->bind(sk, addr, len);
180 
181 	if (len < sizeof(struct sockaddr_pn))
182 		return -EINVAL;
183 	if (spn->spn_family != AF_PHONET)
184 		return -EAFNOSUPPORT;
185 
186 	handle = pn_sockaddr_get_object((struct sockaddr_pn *)addr);
187 	saddr = pn_addr(handle);
188 	if (saddr && phonet_address_lookup(sock_net(sk), saddr))
189 		return -EADDRNOTAVAIL;
190 
191 	lock_sock(sk);
192 	if (sk->sk_state != TCP_CLOSE || pn_port(pn->sobject)) {
193 		err = -EINVAL; /* attempt to rebind */
194 		goto out;
195 	}
196 	WARN_ON(sk_hashed(sk));
197 	mutex_lock(&port_mutex);
198 	err = sk->sk_prot->get_port(sk, pn_port(handle));
199 	if (err)
200 		goto out_port;
201 
202 	/* get_port() sets the port, bind() sets the address if applicable */
203 	pn->sobject = pn_object(saddr, pn_port(pn->sobject));
204 	pn->resource = spn->spn_resource;
205 
206 	/* Enable RX on the socket */
207 	err = sk->sk_prot->hash(sk);
208 out_port:
209 	mutex_unlock(&port_mutex);
210 out:
211 	release_sock(sk);
212 	return err;
213 }
214 
215 static int pn_socket_autobind(struct socket *sock)
216 {
217 	struct sockaddr_pn sa;
218 	int err;
219 
220 	memset(&sa, 0, sizeof(sa));
221 	sa.spn_family = AF_PHONET;
222 	err = pn_socket_bind(sock, (struct sockaddr *)&sa,
223 				sizeof(struct sockaddr_pn));
224 	if (err != -EINVAL)
225 		return err;
226 	BUG_ON(!pn_port(pn_sk(sock->sk)->sobject));
227 	return 0; /* socket was already bound */
228 }
229 
230 static int pn_socket_connect(struct socket *sock, struct sockaddr *addr,
231 		int len, int flags)
232 {
233 	struct sock *sk = sock->sk;
234 	struct pn_sock *pn = pn_sk(sk);
235 	struct sockaddr_pn *spn = (struct sockaddr_pn *)addr;
236 	struct task_struct *tsk = current;
237 	long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
238 	int err;
239 
240 	if (pn_socket_autobind(sock))
241 		return -ENOBUFS;
242 	if (len < sizeof(struct sockaddr_pn))
243 		return -EINVAL;
244 	if (spn->spn_family != AF_PHONET)
245 		return -EAFNOSUPPORT;
246 
247 	lock_sock(sk);
248 
249 	switch (sock->state) {
250 	case SS_UNCONNECTED:
251 		if (sk->sk_state != TCP_CLOSE) {
252 			err = -EISCONN;
253 			goto out;
254 		}
255 		break;
256 	case SS_CONNECTING:
257 		err = -EALREADY;
258 		goto out;
259 	default:
260 		err = -EISCONN;
261 		goto out;
262 	}
263 
264 	pn->dobject = pn_sockaddr_get_object(spn);
265 	pn->resource = pn_sockaddr_get_resource(spn);
266 	sock->state = SS_CONNECTING;
267 
268 	err = sk->sk_prot->connect(sk, addr, len);
269 	if (err) {
270 		sock->state = SS_UNCONNECTED;
271 		pn->dobject = 0;
272 		goto out;
273 	}
274 
275 	while (sk->sk_state == TCP_SYN_SENT) {
276 		DEFINE_WAIT(wait);
277 
278 		if (!timeo) {
279 			err = -EINPROGRESS;
280 			goto out;
281 		}
282 		if (signal_pending(tsk)) {
283 			err = sock_intr_errno(timeo);
284 			goto out;
285 		}
286 
287 		prepare_to_wait_exclusive(sk_sleep(sk), &wait,
288 						TASK_INTERRUPTIBLE);
289 		release_sock(sk);
290 		timeo = schedule_timeout(timeo);
291 		lock_sock(sk);
292 		finish_wait(sk_sleep(sk), &wait);
293 	}
294 
295 	if ((1 << sk->sk_state) & (TCPF_SYN_RECV|TCPF_ESTABLISHED))
296 		err = 0;
297 	else if (sk->sk_state == TCP_CLOSE_WAIT)
298 		err = -ECONNRESET;
299 	else
300 		err = -ECONNREFUSED;
301 	sock->state = err ? SS_UNCONNECTED : SS_CONNECTED;
302 out:
303 	release_sock(sk);
304 	return err;
305 }
306 
307 static int pn_socket_accept(struct socket *sock, struct socket *newsock,
308 			    int flags, bool kern)
309 {
310 	struct sock *sk = sock->sk;
311 	struct sock *newsk;
312 	int err;
313 
314 	if (unlikely(sk->sk_state != TCP_LISTEN))
315 		return -EINVAL;
316 
317 	newsk = sk->sk_prot->accept(sk, flags, &err, kern);
318 	if (!newsk)
319 		return err;
320 
321 	lock_sock(newsk);
322 	sock_graft(newsk, newsock);
323 	newsock->state = SS_CONNECTED;
324 	release_sock(newsk);
325 	return 0;
326 }
327 
328 static int pn_socket_getname(struct socket *sock, struct sockaddr *addr,
329 				int peer)
330 {
331 	struct sock *sk = sock->sk;
332 	struct pn_sock *pn = pn_sk(sk);
333 
334 	memset(addr, 0, sizeof(struct sockaddr_pn));
335 	addr->sa_family = AF_PHONET;
336 	if (!peer) /* Race with bind() here is userland's problem. */
337 		pn_sockaddr_set_object((struct sockaddr_pn *)addr,
338 					pn->sobject);
339 
340 	return sizeof(struct sockaddr_pn);
341 }
342 
343 static __poll_t pn_socket_poll_mask(struct socket *sock, __poll_t events)
344 {
345 	struct sock *sk = sock->sk;
346 	struct pep_sock *pn = pep_sk(sk);
347 	__poll_t mask = 0;
348 
349 	if (sk->sk_state == TCP_CLOSE)
350 		return EPOLLERR;
351 	if (!skb_queue_empty(&sk->sk_receive_queue))
352 		mask |= EPOLLIN | EPOLLRDNORM;
353 	if (!skb_queue_empty(&pn->ctrlreq_queue))
354 		mask |= EPOLLPRI;
355 	if (!mask && sk->sk_state == TCP_CLOSE_WAIT)
356 		return EPOLLHUP;
357 
358 	if (sk->sk_state == TCP_ESTABLISHED &&
359 		refcount_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf &&
360 		atomic_read(&pn->tx_credits))
361 		mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
362 
363 	return mask;
364 }
365 
366 static int pn_socket_ioctl(struct socket *sock, unsigned int cmd,
367 				unsigned long arg)
368 {
369 	struct sock *sk = sock->sk;
370 	struct pn_sock *pn = pn_sk(sk);
371 
372 	if (cmd == SIOCPNGETOBJECT) {
373 		struct net_device *dev;
374 		u16 handle;
375 		u8 saddr;
376 
377 		if (get_user(handle, (__u16 __user *)arg))
378 			return -EFAULT;
379 
380 		lock_sock(sk);
381 		if (sk->sk_bound_dev_if)
382 			dev = dev_get_by_index(sock_net(sk),
383 						sk->sk_bound_dev_if);
384 		else
385 			dev = phonet_device_get(sock_net(sk));
386 		if (dev && (dev->flags & IFF_UP))
387 			saddr = phonet_address_get(dev, pn_addr(handle));
388 		else
389 			saddr = PN_NO_ADDR;
390 		release_sock(sk);
391 
392 		if (dev)
393 			dev_put(dev);
394 		if (saddr == PN_NO_ADDR)
395 			return -EHOSTUNREACH;
396 
397 		handle = pn_object(saddr, pn_port(pn->sobject));
398 		return put_user(handle, (__u16 __user *)arg);
399 	}
400 
401 	return sk->sk_prot->ioctl(sk, cmd, arg);
402 }
403 
404 static int pn_socket_listen(struct socket *sock, int backlog)
405 {
406 	struct sock *sk = sock->sk;
407 	int err = 0;
408 
409 	if (pn_socket_autobind(sock))
410 		return -ENOBUFS;
411 
412 	lock_sock(sk);
413 	if (sock->state != SS_UNCONNECTED) {
414 		err = -EINVAL;
415 		goto out;
416 	}
417 
418 	if (sk->sk_state != TCP_LISTEN) {
419 		sk->sk_state = TCP_LISTEN;
420 		sk->sk_ack_backlog = 0;
421 	}
422 	sk->sk_max_ack_backlog = backlog;
423 out:
424 	release_sock(sk);
425 	return err;
426 }
427 
428 static int pn_socket_sendmsg(struct socket *sock, struct msghdr *m,
429 			     size_t total_len)
430 {
431 	struct sock *sk = sock->sk;
432 
433 	if (pn_socket_autobind(sock))
434 		return -EAGAIN;
435 
436 	return sk->sk_prot->sendmsg(sk, m, total_len);
437 }
438 
439 const struct proto_ops phonet_dgram_ops = {
440 	.family		= AF_PHONET,
441 	.owner		= THIS_MODULE,
442 	.release	= pn_socket_release,
443 	.bind		= pn_socket_bind,
444 	.connect	= sock_no_connect,
445 	.socketpair	= sock_no_socketpair,
446 	.accept		= sock_no_accept,
447 	.getname	= pn_socket_getname,
448 	.poll_mask	= datagram_poll_mask,
449 	.ioctl		= pn_socket_ioctl,
450 	.listen		= sock_no_listen,
451 	.shutdown	= sock_no_shutdown,
452 	.setsockopt	= sock_no_setsockopt,
453 	.getsockopt	= sock_no_getsockopt,
454 #ifdef CONFIG_COMPAT
455 	.compat_setsockopt = sock_no_setsockopt,
456 	.compat_getsockopt = sock_no_getsockopt,
457 #endif
458 	.sendmsg	= pn_socket_sendmsg,
459 	.recvmsg	= sock_common_recvmsg,
460 	.mmap		= sock_no_mmap,
461 	.sendpage	= sock_no_sendpage,
462 };
463 
464 const struct proto_ops phonet_stream_ops = {
465 	.family		= AF_PHONET,
466 	.owner		= THIS_MODULE,
467 	.release	= pn_socket_release,
468 	.bind		= pn_socket_bind,
469 	.connect	= pn_socket_connect,
470 	.socketpair	= sock_no_socketpair,
471 	.accept		= pn_socket_accept,
472 	.getname	= pn_socket_getname,
473 	.poll_mask	= pn_socket_poll_mask,
474 	.ioctl		= pn_socket_ioctl,
475 	.listen		= pn_socket_listen,
476 	.shutdown	= sock_no_shutdown,
477 	.setsockopt	= sock_common_setsockopt,
478 	.getsockopt	= sock_common_getsockopt,
479 #ifdef CONFIG_COMPAT
480 	.compat_setsockopt = compat_sock_common_setsockopt,
481 	.compat_getsockopt = compat_sock_common_getsockopt,
482 #endif
483 	.sendmsg	= pn_socket_sendmsg,
484 	.recvmsg	= sock_common_recvmsg,
485 	.mmap		= sock_no_mmap,
486 	.sendpage	= sock_no_sendpage,
487 };
488 EXPORT_SYMBOL(phonet_stream_ops);
489 
490 /* allocate port for a socket */
491 int pn_sock_get_port(struct sock *sk, unsigned short sport)
492 {
493 	static int port_cur;
494 	struct net *net = sock_net(sk);
495 	struct pn_sock *pn = pn_sk(sk);
496 	struct sockaddr_pn try_sa;
497 	struct sock *tmpsk;
498 
499 	memset(&try_sa, 0, sizeof(struct sockaddr_pn));
500 	try_sa.spn_family = AF_PHONET;
501 	WARN_ON(!mutex_is_locked(&port_mutex));
502 	if (!sport) {
503 		/* search free port */
504 		int port, pmin, pmax;
505 
506 		phonet_get_local_port_range(&pmin, &pmax);
507 		for (port = pmin; port <= pmax; port++) {
508 			port_cur++;
509 			if (port_cur < pmin || port_cur > pmax)
510 				port_cur = pmin;
511 
512 			pn_sockaddr_set_port(&try_sa, port_cur);
513 			tmpsk = pn_find_sock_by_sa(net, &try_sa);
514 			if (tmpsk == NULL) {
515 				sport = port_cur;
516 				goto found;
517 			} else
518 				sock_put(tmpsk);
519 		}
520 	} else {
521 		/* try to find specific port */
522 		pn_sockaddr_set_port(&try_sa, sport);
523 		tmpsk = pn_find_sock_by_sa(net, &try_sa);
524 		if (tmpsk == NULL)
525 			/* No sock there! We can use that port... */
526 			goto found;
527 		else
528 			sock_put(tmpsk);
529 	}
530 	/* the port must be in use already */
531 	return -EADDRINUSE;
532 
533 found:
534 	pn->sobject = pn_object(pn_addr(pn->sobject), sport);
535 	return 0;
536 }
537 EXPORT_SYMBOL(pn_sock_get_port);
538 
539 #ifdef CONFIG_PROC_FS
540 static struct sock *pn_sock_get_idx(struct seq_file *seq, loff_t pos)
541 {
542 	struct net *net = seq_file_net(seq);
543 	struct hlist_head *hlist = pnsocks.hlist;
544 	struct sock *sknode;
545 	unsigned int h;
546 
547 	for (h = 0; h < PN_HASHSIZE; h++) {
548 		sk_for_each_rcu(sknode, hlist) {
549 			if (!net_eq(net, sock_net(sknode)))
550 				continue;
551 			if (!pos)
552 				return sknode;
553 			pos--;
554 		}
555 		hlist++;
556 	}
557 	return NULL;
558 }
559 
560 static struct sock *pn_sock_get_next(struct seq_file *seq, struct sock *sk)
561 {
562 	struct net *net = seq_file_net(seq);
563 
564 	do
565 		sk = sk_next(sk);
566 	while (sk && !net_eq(net, sock_net(sk)));
567 
568 	return sk;
569 }
570 
571 static void *pn_sock_seq_start(struct seq_file *seq, loff_t *pos)
572 	__acquires(rcu)
573 {
574 	rcu_read_lock();
575 	return *pos ? pn_sock_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
576 }
577 
578 static void *pn_sock_seq_next(struct seq_file *seq, void *v, loff_t *pos)
579 {
580 	struct sock *sk;
581 
582 	if (v == SEQ_START_TOKEN)
583 		sk = pn_sock_get_idx(seq, 0);
584 	else
585 		sk = pn_sock_get_next(seq, v);
586 	(*pos)++;
587 	return sk;
588 }
589 
590 static void pn_sock_seq_stop(struct seq_file *seq, void *v)
591 	__releases(rcu)
592 {
593 	rcu_read_unlock();
594 }
595 
596 static int pn_sock_seq_show(struct seq_file *seq, void *v)
597 {
598 	seq_setwidth(seq, 127);
599 	if (v == SEQ_START_TOKEN)
600 		seq_puts(seq, "pt  loc  rem rs st tx_queue rx_queue "
601 			"  uid inode ref pointer drops");
602 	else {
603 		struct sock *sk = v;
604 		struct pn_sock *pn = pn_sk(sk);
605 
606 		seq_printf(seq, "%2d %04X:%04X:%02X %02X %08X:%08X %5d %lu "
607 			"%d %pK %d",
608 			sk->sk_protocol, pn->sobject, pn->dobject,
609 			pn->resource, sk->sk_state,
610 			sk_wmem_alloc_get(sk), sk_rmem_alloc_get(sk),
611 			from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)),
612 			sock_i_ino(sk),
613 			refcount_read(&sk->sk_refcnt), sk,
614 			atomic_read(&sk->sk_drops));
615 	}
616 	seq_pad(seq, '\n');
617 	return 0;
618 }
619 
620 const struct seq_operations pn_sock_seq_ops = {
621 	.start = pn_sock_seq_start,
622 	.next = pn_sock_seq_next,
623 	.stop = pn_sock_seq_stop,
624 	.show = pn_sock_seq_show,
625 };
626 #endif
627 
628 static struct  {
629 	struct sock *sk[256];
630 } pnres;
631 
632 /*
633  * Find and hold socket based on resource.
634  */
635 struct sock *pn_find_sock_by_res(struct net *net, u8 res)
636 {
637 	struct sock *sk;
638 
639 	if (!net_eq(net, &init_net))
640 		return NULL;
641 
642 	rcu_read_lock();
643 	sk = rcu_dereference(pnres.sk[res]);
644 	if (sk)
645 		sock_hold(sk);
646 	rcu_read_unlock();
647 	return sk;
648 }
649 
650 static DEFINE_MUTEX(resource_mutex);
651 
652 int pn_sock_bind_res(struct sock *sk, u8 res)
653 {
654 	int ret = -EADDRINUSE;
655 
656 	if (!net_eq(sock_net(sk), &init_net))
657 		return -ENOIOCTLCMD;
658 	if (!capable(CAP_SYS_ADMIN))
659 		return -EPERM;
660 	if (pn_socket_autobind(sk->sk_socket))
661 		return -EAGAIN;
662 
663 	mutex_lock(&resource_mutex);
664 	if (pnres.sk[res] == NULL) {
665 		sock_hold(sk);
666 		rcu_assign_pointer(pnres.sk[res], sk);
667 		ret = 0;
668 	}
669 	mutex_unlock(&resource_mutex);
670 	return ret;
671 }
672 
673 int pn_sock_unbind_res(struct sock *sk, u8 res)
674 {
675 	int ret = -ENOENT;
676 
677 	if (!capable(CAP_SYS_ADMIN))
678 		return -EPERM;
679 
680 	mutex_lock(&resource_mutex);
681 	if (pnres.sk[res] == sk) {
682 		RCU_INIT_POINTER(pnres.sk[res], NULL);
683 		ret = 0;
684 	}
685 	mutex_unlock(&resource_mutex);
686 
687 	if (ret == 0) {
688 		synchronize_rcu();
689 		sock_put(sk);
690 	}
691 	return ret;
692 }
693 
694 void pn_sock_unbind_all_res(struct sock *sk)
695 {
696 	unsigned int res, match = 0;
697 
698 	mutex_lock(&resource_mutex);
699 	for (res = 0; res < 256; res++) {
700 		if (pnres.sk[res] == sk) {
701 			RCU_INIT_POINTER(pnres.sk[res], NULL);
702 			match++;
703 		}
704 	}
705 	mutex_unlock(&resource_mutex);
706 
707 	while (match > 0) {
708 		__sock_put(sk);
709 		match--;
710 	}
711 	/* Caller is responsible for RCU sync before final sock_put() */
712 }
713 
714 #ifdef CONFIG_PROC_FS
715 static struct sock **pn_res_get_idx(struct seq_file *seq, loff_t pos)
716 {
717 	struct net *net = seq_file_net(seq);
718 	unsigned int i;
719 
720 	if (!net_eq(net, &init_net))
721 		return NULL;
722 
723 	for (i = 0; i < 256; i++) {
724 		if (pnres.sk[i] == NULL)
725 			continue;
726 		if (!pos)
727 			return pnres.sk + i;
728 		pos--;
729 	}
730 	return NULL;
731 }
732 
733 static struct sock **pn_res_get_next(struct seq_file *seq, struct sock **sk)
734 {
735 	struct net *net = seq_file_net(seq);
736 	unsigned int i;
737 
738 	BUG_ON(!net_eq(net, &init_net));
739 
740 	for (i = (sk - pnres.sk) + 1; i < 256; i++)
741 		if (pnres.sk[i])
742 			return pnres.sk + i;
743 	return NULL;
744 }
745 
746 static void *pn_res_seq_start(struct seq_file *seq, loff_t *pos)
747 	__acquires(resource_mutex)
748 {
749 	mutex_lock(&resource_mutex);
750 	return *pos ? pn_res_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
751 }
752 
753 static void *pn_res_seq_next(struct seq_file *seq, void *v, loff_t *pos)
754 {
755 	struct sock **sk;
756 
757 	if (v == SEQ_START_TOKEN)
758 		sk = pn_res_get_idx(seq, 0);
759 	else
760 		sk = pn_res_get_next(seq, v);
761 	(*pos)++;
762 	return sk;
763 }
764 
765 static void pn_res_seq_stop(struct seq_file *seq, void *v)
766 	__releases(resource_mutex)
767 {
768 	mutex_unlock(&resource_mutex);
769 }
770 
771 static int pn_res_seq_show(struct seq_file *seq, void *v)
772 {
773 	seq_setwidth(seq, 63);
774 	if (v == SEQ_START_TOKEN)
775 		seq_puts(seq, "rs   uid inode");
776 	else {
777 		struct sock **psk = v;
778 		struct sock *sk = *psk;
779 
780 		seq_printf(seq, "%02X %5u %lu",
781 			   (int) (psk - pnres.sk),
782 			   from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)),
783 			   sock_i_ino(sk));
784 	}
785 	seq_pad(seq, '\n');
786 	return 0;
787 }
788 
789 const struct seq_operations pn_res_seq_ops = {
790 	.start = pn_res_seq_start,
791 	.next = pn_res_seq_next,
792 	.stop = pn_res_seq_stop,
793 	.show = pn_res_seq_show,
794 };
795 #endif
796