xref: /openbmc/linux/net/phonet/socket.c (revision a44e4f3a)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * File: socket.c
4  *
5  * Phonet sockets
6  *
7  * Copyright (C) 2008 Nokia Corporation.
8  *
9  * Authors: Sakari Ailus <sakari.ailus@nokia.com>
10  *          Rémi Denis-Courmont
11  */
12 
13 #include <linux/gfp.h>
14 #include <linux/kernel.h>
15 #include <linux/net.h>
16 #include <linux/poll.h>
17 #include <linux/sched/signal.h>
18 
19 #include <net/sock.h>
20 #include <net/tcp_states.h>
21 
22 #include <linux/phonet.h>
23 #include <linux/export.h>
24 #include <net/phonet/phonet.h>
25 #include <net/phonet/pep.h>
26 #include <net/phonet/pn_dev.h>
27 
28 static int pn_socket_release(struct socket *sock)
29 {
30 	struct sock *sk = sock->sk;
31 
32 	if (sk) {
33 		sock->sk = NULL;
34 		sk->sk_prot->close(sk, 0);
35 	}
36 	return 0;
37 }
38 
39 #define PN_HASHSIZE	16
40 #define PN_HASHMASK	(PN_HASHSIZE-1)
41 
42 
43 static struct  {
44 	struct hlist_head hlist[PN_HASHSIZE];
45 	struct mutex lock;
46 } pnsocks;
47 
48 void __init pn_sock_init(void)
49 {
50 	unsigned int i;
51 
52 	for (i = 0; i < PN_HASHSIZE; i++)
53 		INIT_HLIST_HEAD(pnsocks.hlist + i);
54 	mutex_init(&pnsocks.lock);
55 }
56 
57 static struct hlist_head *pn_hash_list(u16 obj)
58 {
59 	return pnsocks.hlist + (obj & PN_HASHMASK);
60 }
61 
62 /*
63  * Find address based on socket address, match only certain fields.
64  * Also grab sock if it was found. Remember to sock_put it later.
65  */
66 struct sock *pn_find_sock_by_sa(struct net *net, const struct sockaddr_pn *spn)
67 {
68 	struct sock *sknode;
69 	struct sock *rval = NULL;
70 	u16 obj = pn_sockaddr_get_object(spn);
71 	u8 res = spn->spn_resource;
72 	struct hlist_head *hlist = pn_hash_list(obj);
73 
74 	rcu_read_lock();
75 	sk_for_each_rcu(sknode, hlist) {
76 		struct pn_sock *pn = pn_sk(sknode);
77 		BUG_ON(!pn->sobject); /* unbound socket */
78 
79 		if (!net_eq(sock_net(sknode), net))
80 			continue;
81 		if (pn_port(obj)) {
82 			/* Look up socket by port */
83 			if (pn_port(pn->sobject) != pn_port(obj))
84 				continue;
85 		} else {
86 			/* If port is zero, look up by resource */
87 			if (pn->resource != res)
88 				continue;
89 		}
90 		if (pn_addr(pn->sobject) &&
91 		    pn_addr(pn->sobject) != pn_addr(obj))
92 			continue;
93 
94 		rval = sknode;
95 		sock_hold(sknode);
96 		break;
97 	}
98 	rcu_read_unlock();
99 
100 	return rval;
101 }
102 
103 /* Deliver a broadcast packet (only in bottom-half) */
104 void pn_deliver_sock_broadcast(struct net *net, struct sk_buff *skb)
105 {
106 	struct hlist_head *hlist = pnsocks.hlist;
107 	unsigned int h;
108 
109 	rcu_read_lock();
110 	for (h = 0; h < PN_HASHSIZE; h++) {
111 		struct sock *sknode;
112 
113 		sk_for_each(sknode, hlist) {
114 			struct sk_buff *clone;
115 
116 			if (!net_eq(sock_net(sknode), net))
117 				continue;
118 			if (!sock_flag(sknode, SOCK_BROADCAST))
119 				continue;
120 
121 			clone = skb_clone(skb, GFP_ATOMIC);
122 			if (clone) {
123 				sock_hold(sknode);
124 				sk_receive_skb(sknode, clone, 0);
125 			}
126 		}
127 		hlist++;
128 	}
129 	rcu_read_unlock();
130 }
131 
132 int pn_sock_hash(struct sock *sk)
133 {
134 	struct hlist_head *hlist = pn_hash_list(pn_sk(sk)->sobject);
135 
136 	mutex_lock(&pnsocks.lock);
137 	sk_add_node_rcu(sk, hlist);
138 	mutex_unlock(&pnsocks.lock);
139 
140 	return 0;
141 }
142 EXPORT_SYMBOL(pn_sock_hash);
143 
144 void pn_sock_unhash(struct sock *sk)
145 {
146 	mutex_lock(&pnsocks.lock);
147 	sk_del_node_init_rcu(sk);
148 	mutex_unlock(&pnsocks.lock);
149 	pn_sock_unbind_all_res(sk);
150 	synchronize_rcu();
151 }
152 EXPORT_SYMBOL(pn_sock_unhash);
153 
154 static DEFINE_MUTEX(port_mutex);
155 
156 static int pn_socket_bind(struct socket *sock, struct sockaddr *addr, int len)
157 {
158 	struct sock *sk = sock->sk;
159 	struct pn_sock *pn = pn_sk(sk);
160 	struct sockaddr_pn *spn = (struct sockaddr_pn *)addr;
161 	int err;
162 	u16 handle;
163 	u8 saddr;
164 
165 	if (sk->sk_prot->bind)
166 		return sk->sk_prot->bind(sk, addr, len);
167 
168 	if (len < sizeof(struct sockaddr_pn))
169 		return -EINVAL;
170 	if (spn->spn_family != AF_PHONET)
171 		return -EAFNOSUPPORT;
172 
173 	handle = pn_sockaddr_get_object((struct sockaddr_pn *)addr);
174 	saddr = pn_addr(handle);
175 	if (saddr && phonet_address_lookup(sock_net(sk), saddr))
176 		return -EADDRNOTAVAIL;
177 
178 	lock_sock(sk);
179 	if (sk->sk_state != TCP_CLOSE || pn_port(pn->sobject)) {
180 		err = -EINVAL; /* attempt to rebind */
181 		goto out;
182 	}
183 	WARN_ON(sk_hashed(sk));
184 	mutex_lock(&port_mutex);
185 	err = sk->sk_prot->get_port(sk, pn_port(handle));
186 	if (err)
187 		goto out_port;
188 
189 	/* get_port() sets the port, bind() sets the address if applicable */
190 	pn->sobject = pn_object(saddr, pn_port(pn->sobject));
191 	pn->resource = spn->spn_resource;
192 
193 	/* Enable RX on the socket */
194 	err = sk->sk_prot->hash(sk);
195 out_port:
196 	mutex_unlock(&port_mutex);
197 out:
198 	release_sock(sk);
199 	return err;
200 }
201 
202 static int pn_socket_autobind(struct socket *sock)
203 {
204 	struct sockaddr_pn sa;
205 	int err;
206 
207 	memset(&sa, 0, sizeof(sa));
208 	sa.spn_family = AF_PHONET;
209 	err = pn_socket_bind(sock, (struct sockaddr *)&sa,
210 				sizeof(struct sockaddr_pn));
211 	if (err != -EINVAL)
212 		return err;
213 	BUG_ON(!pn_port(pn_sk(sock->sk)->sobject));
214 	return 0; /* socket was already bound */
215 }
216 
217 static int pn_socket_connect(struct socket *sock, struct sockaddr *addr,
218 		int len, int flags)
219 {
220 	struct sock *sk = sock->sk;
221 	struct pn_sock *pn = pn_sk(sk);
222 	struct sockaddr_pn *spn = (struct sockaddr_pn *)addr;
223 	struct task_struct *tsk = current;
224 	long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
225 	int err;
226 
227 	if (pn_socket_autobind(sock))
228 		return -ENOBUFS;
229 	if (len < sizeof(struct sockaddr_pn))
230 		return -EINVAL;
231 	if (spn->spn_family != AF_PHONET)
232 		return -EAFNOSUPPORT;
233 
234 	lock_sock(sk);
235 
236 	switch (sock->state) {
237 	case SS_UNCONNECTED:
238 		if (sk->sk_state != TCP_CLOSE) {
239 			err = -EISCONN;
240 			goto out;
241 		}
242 		break;
243 	case SS_CONNECTING:
244 		err = -EALREADY;
245 		goto out;
246 	default:
247 		err = -EISCONN;
248 		goto out;
249 	}
250 
251 	pn->dobject = pn_sockaddr_get_object(spn);
252 	pn->resource = pn_sockaddr_get_resource(spn);
253 	sock->state = SS_CONNECTING;
254 
255 	err = sk->sk_prot->connect(sk, addr, len);
256 	if (err) {
257 		sock->state = SS_UNCONNECTED;
258 		pn->dobject = 0;
259 		goto out;
260 	}
261 
262 	while (sk->sk_state == TCP_SYN_SENT) {
263 		DEFINE_WAIT(wait);
264 
265 		if (!timeo) {
266 			err = -EINPROGRESS;
267 			goto out;
268 		}
269 		if (signal_pending(tsk)) {
270 			err = sock_intr_errno(timeo);
271 			goto out;
272 		}
273 
274 		prepare_to_wait_exclusive(sk_sleep(sk), &wait,
275 						TASK_INTERRUPTIBLE);
276 		release_sock(sk);
277 		timeo = schedule_timeout(timeo);
278 		lock_sock(sk);
279 		finish_wait(sk_sleep(sk), &wait);
280 	}
281 
282 	if ((1 << sk->sk_state) & (TCPF_SYN_RECV|TCPF_ESTABLISHED))
283 		err = 0;
284 	else if (sk->sk_state == TCP_CLOSE_WAIT)
285 		err = -ECONNRESET;
286 	else
287 		err = -ECONNREFUSED;
288 	sock->state = err ? SS_UNCONNECTED : SS_CONNECTED;
289 out:
290 	release_sock(sk);
291 	return err;
292 }
293 
294 static int pn_socket_accept(struct socket *sock, struct socket *newsock,
295 			    int flags, bool kern)
296 {
297 	struct sock *sk = sock->sk;
298 	struct sock *newsk;
299 	int err;
300 
301 	if (unlikely(sk->sk_state != TCP_LISTEN))
302 		return -EINVAL;
303 
304 	newsk = sk->sk_prot->accept(sk, flags, &err, kern);
305 	if (!newsk)
306 		return err;
307 
308 	lock_sock(newsk);
309 	sock_graft(newsk, newsock);
310 	newsock->state = SS_CONNECTED;
311 	release_sock(newsk);
312 	return 0;
313 }
314 
315 static int pn_socket_getname(struct socket *sock, struct sockaddr *addr,
316 				int peer)
317 {
318 	struct sock *sk = sock->sk;
319 	struct pn_sock *pn = pn_sk(sk);
320 
321 	memset(addr, 0, sizeof(struct sockaddr_pn));
322 	addr->sa_family = AF_PHONET;
323 	if (!peer) /* Race with bind() here is userland's problem. */
324 		pn_sockaddr_set_object((struct sockaddr_pn *)addr,
325 					pn->sobject);
326 
327 	return sizeof(struct sockaddr_pn);
328 }
329 
330 static __poll_t pn_socket_poll(struct file *file, struct socket *sock,
331 					poll_table *wait)
332 {
333 	struct sock *sk = sock->sk;
334 	struct pep_sock *pn = pep_sk(sk);
335 	__poll_t mask = 0;
336 
337 	poll_wait(file, sk_sleep(sk), wait);
338 
339 	if (sk->sk_state == TCP_CLOSE)
340 		return EPOLLERR;
341 	if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
342 		mask |= EPOLLIN | EPOLLRDNORM;
343 	if (!skb_queue_empty_lockless(&pn->ctrlreq_queue))
344 		mask |= EPOLLPRI;
345 	if (!mask && sk->sk_state == TCP_CLOSE_WAIT)
346 		return EPOLLHUP;
347 
348 	if (sk->sk_state == TCP_ESTABLISHED &&
349 		refcount_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf &&
350 		atomic_read(&pn->tx_credits))
351 		mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
352 
353 	return mask;
354 }
355 
356 static int pn_socket_ioctl(struct socket *sock, unsigned int cmd,
357 				unsigned long arg)
358 {
359 	struct sock *sk = sock->sk;
360 	struct pn_sock *pn = pn_sk(sk);
361 
362 	if (cmd == SIOCPNGETOBJECT) {
363 		struct net_device *dev;
364 		u16 handle;
365 		u8 saddr;
366 
367 		if (get_user(handle, (__u16 __user *)arg))
368 			return -EFAULT;
369 
370 		lock_sock(sk);
371 		if (sk->sk_bound_dev_if)
372 			dev = dev_get_by_index(sock_net(sk),
373 						sk->sk_bound_dev_if);
374 		else
375 			dev = phonet_device_get(sock_net(sk));
376 		if (dev && (dev->flags & IFF_UP))
377 			saddr = phonet_address_get(dev, pn_addr(handle));
378 		else
379 			saddr = PN_NO_ADDR;
380 		release_sock(sk);
381 
382 		if (dev)
383 			dev_put(dev);
384 		if (saddr == PN_NO_ADDR)
385 			return -EHOSTUNREACH;
386 
387 		handle = pn_object(saddr, pn_port(pn->sobject));
388 		return put_user(handle, (__u16 __user *)arg);
389 	}
390 
391 	return sk->sk_prot->ioctl(sk, cmd, arg);
392 }
393 
394 static int pn_socket_listen(struct socket *sock, int backlog)
395 {
396 	struct sock *sk = sock->sk;
397 	int err = 0;
398 
399 	if (pn_socket_autobind(sock))
400 		return -ENOBUFS;
401 
402 	lock_sock(sk);
403 	if (sock->state != SS_UNCONNECTED) {
404 		err = -EINVAL;
405 		goto out;
406 	}
407 
408 	if (sk->sk_state != TCP_LISTEN) {
409 		sk->sk_state = TCP_LISTEN;
410 		sk->sk_ack_backlog = 0;
411 	}
412 	sk->sk_max_ack_backlog = backlog;
413 out:
414 	release_sock(sk);
415 	return err;
416 }
417 
418 static int pn_socket_sendmsg(struct socket *sock, struct msghdr *m,
419 			     size_t total_len)
420 {
421 	struct sock *sk = sock->sk;
422 
423 	if (pn_socket_autobind(sock))
424 		return -EAGAIN;
425 
426 	return sk->sk_prot->sendmsg(sk, m, total_len);
427 }
428 
429 const struct proto_ops phonet_dgram_ops = {
430 	.family		= AF_PHONET,
431 	.owner		= THIS_MODULE,
432 	.release	= pn_socket_release,
433 	.bind		= pn_socket_bind,
434 	.connect	= sock_no_connect,
435 	.socketpair	= sock_no_socketpair,
436 	.accept		= sock_no_accept,
437 	.getname	= pn_socket_getname,
438 	.poll		= datagram_poll,
439 	.ioctl		= pn_socket_ioctl,
440 	.listen		= sock_no_listen,
441 	.shutdown	= sock_no_shutdown,
442 	.setsockopt	= sock_no_setsockopt,
443 	.getsockopt	= sock_no_getsockopt,
444 #ifdef CONFIG_COMPAT
445 	.compat_setsockopt = sock_no_setsockopt,
446 	.compat_getsockopt = sock_no_getsockopt,
447 #endif
448 	.sendmsg	= pn_socket_sendmsg,
449 	.recvmsg	= sock_common_recvmsg,
450 	.mmap		= sock_no_mmap,
451 	.sendpage	= sock_no_sendpage,
452 };
453 
454 const struct proto_ops phonet_stream_ops = {
455 	.family		= AF_PHONET,
456 	.owner		= THIS_MODULE,
457 	.release	= pn_socket_release,
458 	.bind		= pn_socket_bind,
459 	.connect	= pn_socket_connect,
460 	.socketpair	= sock_no_socketpair,
461 	.accept		= pn_socket_accept,
462 	.getname	= pn_socket_getname,
463 	.poll		= pn_socket_poll,
464 	.ioctl		= pn_socket_ioctl,
465 	.listen		= pn_socket_listen,
466 	.shutdown	= sock_no_shutdown,
467 	.setsockopt	= sock_common_setsockopt,
468 	.getsockopt	= sock_common_getsockopt,
469 #ifdef CONFIG_COMPAT
470 	.compat_setsockopt = compat_sock_common_setsockopt,
471 	.compat_getsockopt = compat_sock_common_getsockopt,
472 #endif
473 	.sendmsg	= pn_socket_sendmsg,
474 	.recvmsg	= sock_common_recvmsg,
475 	.mmap		= sock_no_mmap,
476 	.sendpage	= sock_no_sendpage,
477 };
478 EXPORT_SYMBOL(phonet_stream_ops);
479 
480 /* allocate port for a socket */
481 int pn_sock_get_port(struct sock *sk, unsigned short sport)
482 {
483 	static int port_cur;
484 	struct net *net = sock_net(sk);
485 	struct pn_sock *pn = pn_sk(sk);
486 	struct sockaddr_pn try_sa;
487 	struct sock *tmpsk;
488 
489 	memset(&try_sa, 0, sizeof(struct sockaddr_pn));
490 	try_sa.spn_family = AF_PHONET;
491 	WARN_ON(!mutex_is_locked(&port_mutex));
492 	if (!sport) {
493 		/* search free port */
494 		int port, pmin, pmax;
495 
496 		phonet_get_local_port_range(&pmin, &pmax);
497 		for (port = pmin; port <= pmax; port++) {
498 			port_cur++;
499 			if (port_cur < pmin || port_cur > pmax)
500 				port_cur = pmin;
501 
502 			pn_sockaddr_set_port(&try_sa, port_cur);
503 			tmpsk = pn_find_sock_by_sa(net, &try_sa);
504 			if (tmpsk == NULL) {
505 				sport = port_cur;
506 				goto found;
507 			} else
508 				sock_put(tmpsk);
509 		}
510 	} else {
511 		/* try to find specific port */
512 		pn_sockaddr_set_port(&try_sa, sport);
513 		tmpsk = pn_find_sock_by_sa(net, &try_sa);
514 		if (tmpsk == NULL)
515 			/* No sock there! We can use that port... */
516 			goto found;
517 		else
518 			sock_put(tmpsk);
519 	}
520 	/* the port must be in use already */
521 	return -EADDRINUSE;
522 
523 found:
524 	pn->sobject = pn_object(pn_addr(pn->sobject), sport);
525 	return 0;
526 }
527 EXPORT_SYMBOL(pn_sock_get_port);
528 
529 #ifdef CONFIG_PROC_FS
530 static struct sock *pn_sock_get_idx(struct seq_file *seq, loff_t pos)
531 {
532 	struct net *net = seq_file_net(seq);
533 	struct hlist_head *hlist = pnsocks.hlist;
534 	struct sock *sknode;
535 	unsigned int h;
536 
537 	for (h = 0; h < PN_HASHSIZE; h++) {
538 		sk_for_each_rcu(sknode, hlist) {
539 			if (!net_eq(net, sock_net(sknode)))
540 				continue;
541 			if (!pos)
542 				return sknode;
543 			pos--;
544 		}
545 		hlist++;
546 	}
547 	return NULL;
548 }
549 
550 static struct sock *pn_sock_get_next(struct seq_file *seq, struct sock *sk)
551 {
552 	struct net *net = seq_file_net(seq);
553 
554 	do
555 		sk = sk_next(sk);
556 	while (sk && !net_eq(net, sock_net(sk)));
557 
558 	return sk;
559 }
560 
561 static void *pn_sock_seq_start(struct seq_file *seq, loff_t *pos)
562 	__acquires(rcu)
563 {
564 	rcu_read_lock();
565 	return *pos ? pn_sock_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
566 }
567 
568 static void *pn_sock_seq_next(struct seq_file *seq, void *v, loff_t *pos)
569 {
570 	struct sock *sk;
571 
572 	if (v == SEQ_START_TOKEN)
573 		sk = pn_sock_get_idx(seq, 0);
574 	else
575 		sk = pn_sock_get_next(seq, v);
576 	(*pos)++;
577 	return sk;
578 }
579 
580 static void pn_sock_seq_stop(struct seq_file *seq, void *v)
581 	__releases(rcu)
582 {
583 	rcu_read_unlock();
584 }
585 
586 static int pn_sock_seq_show(struct seq_file *seq, void *v)
587 {
588 	seq_setwidth(seq, 127);
589 	if (v == SEQ_START_TOKEN)
590 		seq_puts(seq, "pt  loc  rem rs st tx_queue rx_queue "
591 			"  uid inode ref pointer drops");
592 	else {
593 		struct sock *sk = v;
594 		struct pn_sock *pn = pn_sk(sk);
595 
596 		seq_printf(seq, "%2d %04X:%04X:%02X %02X %08X:%08X %5d %lu "
597 			"%d %pK %u",
598 			sk->sk_protocol, pn->sobject, pn->dobject,
599 			pn->resource, sk->sk_state,
600 			sk_wmem_alloc_get(sk), sk_rmem_alloc_get(sk),
601 			from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)),
602 			sock_i_ino(sk),
603 			refcount_read(&sk->sk_refcnt), sk,
604 			atomic_read(&sk->sk_drops));
605 	}
606 	seq_pad(seq, '\n');
607 	return 0;
608 }
609 
610 const struct seq_operations pn_sock_seq_ops = {
611 	.start = pn_sock_seq_start,
612 	.next = pn_sock_seq_next,
613 	.stop = pn_sock_seq_stop,
614 	.show = pn_sock_seq_show,
615 };
616 #endif
617 
618 static struct  {
619 	struct sock *sk[256];
620 } pnres;
621 
622 /*
623  * Find and hold socket based on resource.
624  */
625 struct sock *pn_find_sock_by_res(struct net *net, u8 res)
626 {
627 	struct sock *sk;
628 
629 	if (!net_eq(net, &init_net))
630 		return NULL;
631 
632 	rcu_read_lock();
633 	sk = rcu_dereference(pnres.sk[res]);
634 	if (sk)
635 		sock_hold(sk);
636 	rcu_read_unlock();
637 	return sk;
638 }
639 
640 static DEFINE_MUTEX(resource_mutex);
641 
642 int pn_sock_bind_res(struct sock *sk, u8 res)
643 {
644 	int ret = -EADDRINUSE;
645 
646 	if (!net_eq(sock_net(sk), &init_net))
647 		return -ENOIOCTLCMD;
648 	if (!capable(CAP_SYS_ADMIN))
649 		return -EPERM;
650 	if (pn_socket_autobind(sk->sk_socket))
651 		return -EAGAIN;
652 
653 	mutex_lock(&resource_mutex);
654 	if (pnres.sk[res] == NULL) {
655 		sock_hold(sk);
656 		rcu_assign_pointer(pnres.sk[res], sk);
657 		ret = 0;
658 	}
659 	mutex_unlock(&resource_mutex);
660 	return ret;
661 }
662 
663 int pn_sock_unbind_res(struct sock *sk, u8 res)
664 {
665 	int ret = -ENOENT;
666 
667 	if (!capable(CAP_SYS_ADMIN))
668 		return -EPERM;
669 
670 	mutex_lock(&resource_mutex);
671 	if (pnres.sk[res] == sk) {
672 		RCU_INIT_POINTER(pnres.sk[res], NULL);
673 		ret = 0;
674 	}
675 	mutex_unlock(&resource_mutex);
676 
677 	if (ret == 0) {
678 		synchronize_rcu();
679 		sock_put(sk);
680 	}
681 	return ret;
682 }
683 
684 void pn_sock_unbind_all_res(struct sock *sk)
685 {
686 	unsigned int res, match = 0;
687 
688 	mutex_lock(&resource_mutex);
689 	for (res = 0; res < 256; res++) {
690 		if (pnres.sk[res] == sk) {
691 			RCU_INIT_POINTER(pnres.sk[res], NULL);
692 			match++;
693 		}
694 	}
695 	mutex_unlock(&resource_mutex);
696 
697 	while (match > 0) {
698 		__sock_put(sk);
699 		match--;
700 	}
701 	/* Caller is responsible for RCU sync before final sock_put() */
702 }
703 
704 #ifdef CONFIG_PROC_FS
705 static struct sock **pn_res_get_idx(struct seq_file *seq, loff_t pos)
706 {
707 	struct net *net = seq_file_net(seq);
708 	unsigned int i;
709 
710 	if (!net_eq(net, &init_net))
711 		return NULL;
712 
713 	for (i = 0; i < 256; i++) {
714 		if (pnres.sk[i] == NULL)
715 			continue;
716 		if (!pos)
717 			return pnres.sk + i;
718 		pos--;
719 	}
720 	return NULL;
721 }
722 
723 static struct sock **pn_res_get_next(struct seq_file *seq, struct sock **sk)
724 {
725 	struct net *net = seq_file_net(seq);
726 	unsigned int i;
727 
728 	BUG_ON(!net_eq(net, &init_net));
729 
730 	for (i = (sk - pnres.sk) + 1; i < 256; i++)
731 		if (pnres.sk[i])
732 			return pnres.sk + i;
733 	return NULL;
734 }
735 
736 static void *pn_res_seq_start(struct seq_file *seq, loff_t *pos)
737 	__acquires(resource_mutex)
738 {
739 	mutex_lock(&resource_mutex);
740 	return *pos ? pn_res_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
741 }
742 
743 static void *pn_res_seq_next(struct seq_file *seq, void *v, loff_t *pos)
744 {
745 	struct sock **sk;
746 
747 	if (v == SEQ_START_TOKEN)
748 		sk = pn_res_get_idx(seq, 0);
749 	else
750 		sk = pn_res_get_next(seq, v);
751 	(*pos)++;
752 	return sk;
753 }
754 
755 static void pn_res_seq_stop(struct seq_file *seq, void *v)
756 	__releases(resource_mutex)
757 {
758 	mutex_unlock(&resource_mutex);
759 }
760 
761 static int pn_res_seq_show(struct seq_file *seq, void *v)
762 {
763 	seq_setwidth(seq, 63);
764 	if (v == SEQ_START_TOKEN)
765 		seq_puts(seq, "rs   uid inode");
766 	else {
767 		struct sock **psk = v;
768 		struct sock *sk = *psk;
769 
770 		seq_printf(seq, "%02X %5u %lu",
771 			   (int) (psk - pnres.sk),
772 			   from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)),
773 			   sock_i_ino(sk));
774 	}
775 	seq_pad(seq, '\n');
776 	return 0;
777 }
778 
779 const struct seq_operations pn_res_seq_ops = {
780 	.start = pn_res_seq_start,
781 	.next = pn_res_seq_next,
782 	.stop = pn_res_seq_stop,
783 	.show = pn_res_seq_show,
784 };
785 #endif
786