xref: /openbmc/linux/net/ipv6/ip6_flowlabel.c (revision f15cbe6f1a4b4d9df59142fc8e4abb973302cf44)
1 /*
2  *	ip6_flowlabel.c		IPv6 flowlabel manager.
3  *
4  *	This program is free software; you can redistribute it and/or
5  *      modify it under the terms of the GNU General Public License
6  *      as published by the Free Software Foundation; either version
7  *      2 of the License, or (at your option) any later version.
8  *
9  *	Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10  */
11 
12 #include <linux/capability.h>
13 #include <linux/errno.h>
14 #include <linux/types.h>
15 #include <linux/socket.h>
16 #include <linux/net.h>
17 #include <linux/netdevice.h>
18 #include <linux/if_arp.h>
19 #include <linux/in6.h>
20 #include <linux/route.h>
21 #include <linux/proc_fs.h>
22 #include <linux/seq_file.h>
23 
24 #include <net/net_namespace.h>
25 #include <net/sock.h>
26 
27 #include <net/ipv6.h>
28 #include <net/ndisc.h>
29 #include <net/protocol.h>
30 #include <net/ip6_route.h>
31 #include <net/addrconf.h>
32 #include <net/rawv6.h>
33 #include <net/icmp.h>
34 #include <net/transp_v6.h>
35 
36 #include <asm/uaccess.h>
37 
38 #define FL_MIN_LINGER	6	/* Minimal linger. It is set to 6sec specified
39 				   in old IPv6 RFC. Well, it was reasonable value.
40 				 */
41 #define FL_MAX_LINGER	60	/* Maximal linger timeout */
42 
43 /* FL hash table */
44 
45 #define FL_MAX_PER_SOCK	32
46 #define FL_MAX_SIZE	4096
47 #define FL_HASH_MASK	255
48 #define FL_HASH(l)	(ntohl(l)&FL_HASH_MASK)
49 
50 static atomic_t fl_size = ATOMIC_INIT(0);
51 static struct ip6_flowlabel *fl_ht[FL_HASH_MASK+1];
52 
53 static void ip6_fl_gc(unsigned long dummy);
54 static DEFINE_TIMER(ip6_fl_gc_timer, ip6_fl_gc, 0, 0);
55 
56 /* FL hash table lock: it protects only of GC */
57 
58 static DEFINE_RWLOCK(ip6_fl_lock);
59 
60 /* Big socket sock */
61 
62 static DEFINE_RWLOCK(ip6_sk_fl_lock);
63 
64 
65 static inline struct ip6_flowlabel *__fl_lookup(struct net *net, __be32 label)
66 {
67 	struct ip6_flowlabel *fl;
68 
69 	for (fl=fl_ht[FL_HASH(label)]; fl; fl = fl->next) {
70 		if (fl->label == label && fl->fl_net == net)
71 			return fl;
72 	}
73 	return NULL;
74 }
75 
76 static struct ip6_flowlabel *fl_lookup(struct net *net, __be32 label)
77 {
78 	struct ip6_flowlabel *fl;
79 
80 	read_lock_bh(&ip6_fl_lock);
81 	fl = __fl_lookup(net, label);
82 	if (fl)
83 		atomic_inc(&fl->users);
84 	read_unlock_bh(&ip6_fl_lock);
85 	return fl;
86 }
87 
88 
89 static void fl_free(struct ip6_flowlabel *fl)
90 {
91 	if (fl) {
92 		release_net(fl->fl_net);
93 		kfree(fl->opt);
94 	}
95 	kfree(fl);
96 }
97 
98 static void fl_release(struct ip6_flowlabel *fl)
99 {
100 	write_lock_bh(&ip6_fl_lock);
101 
102 	fl->lastuse = jiffies;
103 	if (atomic_dec_and_test(&fl->users)) {
104 		unsigned long ttd = fl->lastuse + fl->linger;
105 		if (time_after(ttd, fl->expires))
106 			fl->expires = ttd;
107 		ttd = fl->expires;
108 		if (fl->opt && fl->share == IPV6_FL_S_EXCL) {
109 			struct ipv6_txoptions *opt = fl->opt;
110 			fl->opt = NULL;
111 			kfree(opt);
112 		}
113 		if (!timer_pending(&ip6_fl_gc_timer) ||
114 		    time_after(ip6_fl_gc_timer.expires, ttd))
115 			mod_timer(&ip6_fl_gc_timer, ttd);
116 	}
117 	write_unlock_bh(&ip6_fl_lock);
118 }
119 
120 static void ip6_fl_gc(unsigned long dummy)
121 {
122 	int i;
123 	unsigned long now = jiffies;
124 	unsigned long sched = 0;
125 
126 	write_lock(&ip6_fl_lock);
127 
128 	for (i=0; i<=FL_HASH_MASK; i++) {
129 		struct ip6_flowlabel *fl, **flp;
130 		flp = &fl_ht[i];
131 		while ((fl=*flp) != NULL) {
132 			if (atomic_read(&fl->users) == 0) {
133 				unsigned long ttd = fl->lastuse + fl->linger;
134 				if (time_after(ttd, fl->expires))
135 					fl->expires = ttd;
136 				ttd = fl->expires;
137 				if (time_after_eq(now, ttd)) {
138 					*flp = fl->next;
139 					fl_free(fl);
140 					atomic_dec(&fl_size);
141 					continue;
142 				}
143 				if (!sched || time_before(ttd, sched))
144 					sched = ttd;
145 			}
146 			flp = &fl->next;
147 		}
148 	}
149 	if (!sched && atomic_read(&fl_size))
150 		sched = now + FL_MAX_LINGER;
151 	if (sched) {
152 		mod_timer(&ip6_fl_gc_timer, sched);
153 	}
154 	write_unlock(&ip6_fl_lock);
155 }
156 
157 static void ip6_fl_purge(struct net *net)
158 {
159 	int i;
160 
161 	write_lock(&ip6_fl_lock);
162 	for (i = 0; i <= FL_HASH_MASK; i++) {
163 		struct ip6_flowlabel *fl, **flp;
164 		flp = &fl_ht[i];
165 		while ((fl = *flp) != NULL) {
166 			if (fl->fl_net == net && atomic_read(&fl->users) == 0) {
167 				*flp = fl->next;
168 				fl_free(fl);
169 				atomic_dec(&fl_size);
170 				continue;
171 			}
172 			flp = &fl->next;
173 		}
174 	}
175 	write_unlock(&ip6_fl_lock);
176 }
177 
178 static struct ip6_flowlabel *fl_intern(struct net *net,
179 				       struct ip6_flowlabel *fl, __be32 label)
180 {
181 	struct ip6_flowlabel *lfl;
182 
183 	fl->label = label & IPV6_FLOWLABEL_MASK;
184 
185 	write_lock_bh(&ip6_fl_lock);
186 	if (label == 0) {
187 		for (;;) {
188 			fl->label = htonl(net_random())&IPV6_FLOWLABEL_MASK;
189 			if (fl->label) {
190 				lfl = __fl_lookup(net, fl->label);
191 				if (lfl == NULL)
192 					break;
193 			}
194 		}
195 	} else {
196 		/*
197 		 * we dropper the ip6_fl_lock, so this entry could reappear
198 		 * and we need to recheck with it.
199 		 *
200 		 * OTOH no need to search the active socket first, like it is
201 		 * done in ipv6_flowlabel_opt - sock is locked, so new entry
202 		 * with the same label can only appear on another sock
203 		 */
204 		lfl = __fl_lookup(net, fl->label);
205 		if (lfl != NULL) {
206 			atomic_inc(&lfl->users);
207 			write_unlock_bh(&ip6_fl_lock);
208 			return lfl;
209 		}
210 	}
211 
212 	fl->lastuse = jiffies;
213 	fl->next = fl_ht[FL_HASH(fl->label)];
214 	fl_ht[FL_HASH(fl->label)] = fl;
215 	atomic_inc(&fl_size);
216 	write_unlock_bh(&ip6_fl_lock);
217 	return NULL;
218 }
219 
220 
221 
222 /* Socket flowlabel lists */
223 
224 struct ip6_flowlabel * fl6_sock_lookup(struct sock *sk, __be32 label)
225 {
226 	struct ipv6_fl_socklist *sfl;
227 	struct ipv6_pinfo *np = inet6_sk(sk);
228 
229 	label &= IPV6_FLOWLABEL_MASK;
230 
231 	read_lock_bh(&ip6_sk_fl_lock);
232 	for (sfl=np->ipv6_fl_list; sfl; sfl = sfl->next) {
233 		struct ip6_flowlabel *fl = sfl->fl;
234 		if (fl->label == label) {
235 			fl->lastuse = jiffies;
236 			atomic_inc(&fl->users);
237 			read_unlock_bh(&ip6_sk_fl_lock);
238 			return fl;
239 		}
240 	}
241 	read_unlock_bh(&ip6_sk_fl_lock);
242 	return NULL;
243 }
244 
245 EXPORT_SYMBOL_GPL(fl6_sock_lookup);
246 
247 void fl6_free_socklist(struct sock *sk)
248 {
249 	struct ipv6_pinfo *np = inet6_sk(sk);
250 	struct ipv6_fl_socklist *sfl;
251 
252 	while ((sfl = np->ipv6_fl_list) != NULL) {
253 		np->ipv6_fl_list = sfl->next;
254 		fl_release(sfl->fl);
255 		kfree(sfl);
256 	}
257 }
258 
259 /* Service routines */
260 
261 
262 /*
263    It is the only difficult place. flowlabel enforces equal headers
264    before and including routing header, however user may supply options
265    following rthdr.
266  */
267 
268 struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions * opt_space,
269 					 struct ip6_flowlabel * fl,
270 					 struct ipv6_txoptions * fopt)
271 {
272 	struct ipv6_txoptions * fl_opt = fl->opt;
273 
274 	if (fopt == NULL || fopt->opt_flen == 0)
275 		return fl_opt;
276 
277 	if (fl_opt != NULL) {
278 		opt_space->hopopt = fl_opt->hopopt;
279 		opt_space->dst0opt = fl_opt->dst0opt;
280 		opt_space->srcrt = fl_opt->srcrt;
281 		opt_space->opt_nflen = fl_opt->opt_nflen;
282 	} else {
283 		if (fopt->opt_nflen == 0)
284 			return fopt;
285 		opt_space->hopopt = NULL;
286 		opt_space->dst0opt = NULL;
287 		opt_space->srcrt = NULL;
288 		opt_space->opt_nflen = 0;
289 	}
290 	opt_space->dst1opt = fopt->dst1opt;
291 	opt_space->opt_flen = fopt->opt_flen;
292 	return opt_space;
293 }
294 
295 static unsigned long check_linger(unsigned long ttl)
296 {
297 	if (ttl < FL_MIN_LINGER)
298 		return FL_MIN_LINGER*HZ;
299 	if (ttl > FL_MAX_LINGER && !capable(CAP_NET_ADMIN))
300 		return 0;
301 	return ttl*HZ;
302 }
303 
304 static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned long expires)
305 {
306 	linger = check_linger(linger);
307 	if (!linger)
308 		return -EPERM;
309 	expires = check_linger(expires);
310 	if (!expires)
311 		return -EPERM;
312 	fl->lastuse = jiffies;
313 	if (time_before(fl->linger, linger))
314 		fl->linger = linger;
315 	if (time_before(expires, fl->linger))
316 		expires = fl->linger;
317 	if (time_before(fl->expires, fl->lastuse + expires))
318 		fl->expires = fl->lastuse + expires;
319 	return 0;
320 }
321 
322 static struct ip6_flowlabel *
323 fl_create(struct net *net, struct in6_flowlabel_req *freq, char __user *optval,
324 	  int optlen, int *err_p)
325 {
326 	struct ip6_flowlabel *fl;
327 	int olen;
328 	int addr_type;
329 	int err;
330 
331 	err = -ENOMEM;
332 	fl = kzalloc(sizeof(*fl), GFP_KERNEL);
333 	if (fl == NULL)
334 		goto done;
335 
336 	olen = optlen - CMSG_ALIGN(sizeof(*freq));
337 	if (olen > 0) {
338 		struct msghdr msg;
339 		struct flowi flowi;
340 		int junk;
341 
342 		err = -ENOMEM;
343 		fl->opt = kmalloc(sizeof(*fl->opt) + olen, GFP_KERNEL);
344 		if (fl->opt == NULL)
345 			goto done;
346 
347 		memset(fl->opt, 0, sizeof(*fl->opt));
348 		fl->opt->tot_len = sizeof(*fl->opt) + olen;
349 		err = -EFAULT;
350 		if (copy_from_user(fl->opt+1, optval+CMSG_ALIGN(sizeof(*freq)), olen))
351 			goto done;
352 
353 		msg.msg_controllen = olen;
354 		msg.msg_control = (void*)(fl->opt+1);
355 		flowi.oif = 0;
356 
357 		err = datagram_send_ctl(net, &msg, &flowi, fl->opt, &junk, &junk);
358 		if (err)
359 			goto done;
360 		err = -EINVAL;
361 		if (fl->opt->opt_flen)
362 			goto done;
363 		if (fl->opt->opt_nflen == 0) {
364 			kfree(fl->opt);
365 			fl->opt = NULL;
366 		}
367 	}
368 
369 	fl->fl_net = hold_net(net);
370 	fl->expires = jiffies;
371 	err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
372 	if (err)
373 		goto done;
374 	fl->share = freq->flr_share;
375 	addr_type = ipv6_addr_type(&freq->flr_dst);
376 	if ((addr_type&IPV6_ADDR_MAPPED)
377 	    || addr_type == IPV6_ADDR_ANY) {
378 		err = -EINVAL;
379 		goto done;
380 	}
381 	ipv6_addr_copy(&fl->dst, &freq->flr_dst);
382 	atomic_set(&fl->users, 1);
383 	switch (fl->share) {
384 	case IPV6_FL_S_EXCL:
385 	case IPV6_FL_S_ANY:
386 		break;
387 	case IPV6_FL_S_PROCESS:
388 		fl->owner = current->pid;
389 		break;
390 	case IPV6_FL_S_USER:
391 		fl->owner = current->euid;
392 		break;
393 	default:
394 		err = -EINVAL;
395 		goto done;
396 	}
397 	return fl;
398 
399 done:
400 	fl_free(fl);
401 	*err_p = err;
402 	return NULL;
403 }
404 
405 static int mem_check(struct sock *sk)
406 {
407 	struct ipv6_pinfo *np = inet6_sk(sk);
408 	struct ipv6_fl_socklist *sfl;
409 	int room = FL_MAX_SIZE - atomic_read(&fl_size);
410 	int count = 0;
411 
412 	if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
413 		return 0;
414 
415 	for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next)
416 		count++;
417 
418 	if (room <= 0 ||
419 	    ((count >= FL_MAX_PER_SOCK ||
420 	     (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4)
421 	     && !capable(CAP_NET_ADMIN)))
422 		return -ENOBUFS;
423 
424 	return 0;
425 }
426 
427 static int ipv6_hdr_cmp(struct ipv6_opt_hdr *h1, struct ipv6_opt_hdr *h2)
428 {
429 	if (h1 == h2)
430 		return 0;
431 	if (h1 == NULL || h2 == NULL)
432 		return 1;
433 	if (h1->hdrlen != h2->hdrlen)
434 		return 1;
435 	return memcmp(h1+1, h2+1, ((h1->hdrlen+1)<<3) - sizeof(*h1));
436 }
437 
438 static int ipv6_opt_cmp(struct ipv6_txoptions *o1, struct ipv6_txoptions *o2)
439 {
440 	if (o1 == o2)
441 		return 0;
442 	if (o1 == NULL || o2 == NULL)
443 		return 1;
444 	if (o1->opt_nflen != o2->opt_nflen)
445 		return 1;
446 	if (ipv6_hdr_cmp(o1->hopopt, o2->hopopt))
447 		return 1;
448 	if (ipv6_hdr_cmp(o1->dst0opt, o2->dst0opt))
449 		return 1;
450 	if (ipv6_hdr_cmp((struct ipv6_opt_hdr *)o1->srcrt, (struct ipv6_opt_hdr *)o2->srcrt))
451 		return 1;
452 	return 0;
453 }
454 
455 static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
456 		struct ip6_flowlabel *fl)
457 {
458 	write_lock_bh(&ip6_sk_fl_lock);
459 	sfl->fl = fl;
460 	sfl->next = np->ipv6_fl_list;
461 	np->ipv6_fl_list = sfl;
462 	write_unlock_bh(&ip6_sk_fl_lock);
463 }
464 
465 int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
466 {
467 	int err;
468 	struct net *net = sock_net(sk);
469 	struct ipv6_pinfo *np = inet6_sk(sk);
470 	struct in6_flowlabel_req freq;
471 	struct ipv6_fl_socklist *sfl1=NULL;
472 	struct ipv6_fl_socklist *sfl, **sflp;
473 	struct ip6_flowlabel *fl, *fl1 = NULL;
474 
475 
476 	if (optlen < sizeof(freq))
477 		return -EINVAL;
478 
479 	if (copy_from_user(&freq, optval, sizeof(freq)))
480 		return -EFAULT;
481 
482 	switch (freq.flr_action) {
483 	case IPV6_FL_A_PUT:
484 		write_lock_bh(&ip6_sk_fl_lock);
485 		for (sflp = &np->ipv6_fl_list; (sfl=*sflp)!=NULL; sflp = &sfl->next) {
486 			if (sfl->fl->label == freq.flr_label) {
487 				if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK))
488 					np->flow_label &= ~IPV6_FLOWLABEL_MASK;
489 				*sflp = sfl->next;
490 				write_unlock_bh(&ip6_sk_fl_lock);
491 				fl_release(sfl->fl);
492 				kfree(sfl);
493 				return 0;
494 			}
495 		}
496 		write_unlock_bh(&ip6_sk_fl_lock);
497 		return -ESRCH;
498 
499 	case IPV6_FL_A_RENEW:
500 		read_lock_bh(&ip6_sk_fl_lock);
501 		for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) {
502 			if (sfl->fl->label == freq.flr_label) {
503 				err = fl6_renew(sfl->fl, freq.flr_linger, freq.flr_expires);
504 				read_unlock_bh(&ip6_sk_fl_lock);
505 				return err;
506 			}
507 		}
508 		read_unlock_bh(&ip6_sk_fl_lock);
509 
510 		if (freq.flr_share == IPV6_FL_S_NONE && capable(CAP_NET_ADMIN)) {
511 			fl = fl_lookup(net, freq.flr_label);
512 			if (fl) {
513 				err = fl6_renew(fl, freq.flr_linger, freq.flr_expires);
514 				fl_release(fl);
515 				return err;
516 			}
517 		}
518 		return -ESRCH;
519 
520 	case IPV6_FL_A_GET:
521 		if (freq.flr_label & ~IPV6_FLOWLABEL_MASK)
522 			return -EINVAL;
523 
524 		fl = fl_create(net, &freq, optval, optlen, &err);
525 		if (fl == NULL)
526 			return err;
527 		sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
528 
529 		if (freq.flr_label) {
530 			err = -EEXIST;
531 			read_lock_bh(&ip6_sk_fl_lock);
532 			for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) {
533 				if (sfl->fl->label == freq.flr_label) {
534 					if (freq.flr_flags&IPV6_FL_F_EXCL) {
535 						read_unlock_bh(&ip6_sk_fl_lock);
536 						goto done;
537 					}
538 					fl1 = sfl->fl;
539 					atomic_inc(&fl1->users);
540 					break;
541 				}
542 			}
543 			read_unlock_bh(&ip6_sk_fl_lock);
544 
545 			if (fl1 == NULL)
546 				fl1 = fl_lookup(net, freq.flr_label);
547 			if (fl1) {
548 recheck:
549 				err = -EEXIST;
550 				if (freq.flr_flags&IPV6_FL_F_EXCL)
551 					goto release;
552 				err = -EPERM;
553 				if (fl1->share == IPV6_FL_S_EXCL ||
554 				    fl1->share != fl->share ||
555 				    fl1->owner != fl->owner)
556 					goto release;
557 
558 				err = -EINVAL;
559 				if (!ipv6_addr_equal(&fl1->dst, &fl->dst) ||
560 				    ipv6_opt_cmp(fl1->opt, fl->opt))
561 					goto release;
562 
563 				err = -ENOMEM;
564 				if (sfl1 == NULL)
565 					goto release;
566 				if (fl->linger > fl1->linger)
567 					fl1->linger = fl->linger;
568 				if ((long)(fl->expires - fl1->expires) > 0)
569 					fl1->expires = fl->expires;
570 				fl_link(np, sfl1, fl1);
571 				fl_free(fl);
572 				return 0;
573 
574 release:
575 				fl_release(fl1);
576 				goto done;
577 			}
578 		}
579 		err = -ENOENT;
580 		if (!(freq.flr_flags&IPV6_FL_F_CREATE))
581 			goto done;
582 
583 		err = -ENOMEM;
584 		if (sfl1 == NULL || (err = mem_check(sk)) != 0)
585 			goto done;
586 
587 		fl1 = fl_intern(net, fl, freq.flr_label);
588 		if (fl1 != NULL)
589 			goto recheck;
590 
591 		if (!freq.flr_label) {
592 			if (copy_to_user(&((struct in6_flowlabel_req __user *) optval)->flr_label,
593 					 &fl->label, sizeof(fl->label))) {
594 				/* Intentionally ignore fault. */
595 			}
596 		}
597 
598 		fl_link(np, sfl1, fl);
599 		return 0;
600 
601 	default:
602 		return -EINVAL;
603 	}
604 
605 done:
606 	fl_free(fl);
607 	kfree(sfl1);
608 	return err;
609 }
610 
611 #ifdef CONFIG_PROC_FS
612 
613 struct ip6fl_iter_state {
614 	struct seq_net_private p;
615 	int bucket;
616 };
617 
618 #define ip6fl_seq_private(seq)	((struct ip6fl_iter_state *)(seq)->private)
619 
620 static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
621 {
622 	struct ip6_flowlabel *fl = NULL;
623 	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
624 	struct net *net = seq_file_net(seq);
625 
626 	for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {
627 		fl = fl_ht[state->bucket];
628 
629 		while (fl && fl->fl_net != net)
630 			fl = fl->next;
631 		if (fl)
632 			break;
633 	}
634 	return fl;
635 }
636 
637 static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl)
638 {
639 	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
640 	struct net *net = seq_file_net(seq);
641 
642 	fl = fl->next;
643 try_again:
644 	while (fl && fl->fl_net != net)
645 		fl = fl->next;
646 
647 	while (!fl) {
648 		if (++state->bucket <= FL_HASH_MASK) {
649 			fl = fl_ht[state->bucket];
650 			goto try_again;
651 		} else
652 			break;
653 	}
654 	return fl;
655 }
656 
657 static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
658 {
659 	struct ip6_flowlabel *fl = ip6fl_get_first(seq);
660 	if (fl)
661 		while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL)
662 			--pos;
663 	return pos ? NULL : fl;
664 }
665 
666 static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
667 	__acquires(ip6_fl_lock)
668 {
669 	read_lock_bh(&ip6_fl_lock);
670 	return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
671 }
672 
673 static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
674 {
675 	struct ip6_flowlabel *fl;
676 
677 	if (v == SEQ_START_TOKEN)
678 		fl = ip6fl_get_first(seq);
679 	else
680 		fl = ip6fl_get_next(seq, v);
681 	++*pos;
682 	return fl;
683 }
684 
685 static void ip6fl_seq_stop(struct seq_file *seq, void *v)
686 	__releases(ip6_fl_lock)
687 {
688 	read_unlock_bh(&ip6_fl_lock);
689 }
690 
691 static int ip6fl_seq_show(struct seq_file *seq, void *v)
692 {
693 	if (v == SEQ_START_TOKEN)
694 		seq_printf(seq, "%-5s %-1s %-6s %-6s %-6s %-8s %-32s %s\n",
695 			   "Label", "S", "Owner", "Users", "Linger", "Expires", "Dst", "Opt");
696 	else {
697 		struct ip6_flowlabel *fl = v;
698 		seq_printf(seq,
699 			   "%05X %-1d %-6d %-6d %-6ld %-8ld " NIP6_SEQFMT " %-4d\n",
700 			   (unsigned)ntohl(fl->label),
701 			   fl->share,
702 			   (unsigned)fl->owner,
703 			   atomic_read(&fl->users),
704 			   fl->linger/HZ,
705 			   (long)(fl->expires - jiffies)/HZ,
706 			   NIP6(fl->dst),
707 			   fl->opt ? fl->opt->opt_nflen : 0);
708 	}
709 	return 0;
710 }
711 
712 static const struct seq_operations ip6fl_seq_ops = {
713 	.start	=	ip6fl_seq_start,
714 	.next	=	ip6fl_seq_next,
715 	.stop	=	ip6fl_seq_stop,
716 	.show	=	ip6fl_seq_show,
717 };
718 
719 static int ip6fl_seq_open(struct inode *inode, struct file *file)
720 {
721 	return seq_open_net(inode, file, &ip6fl_seq_ops,
722 			    sizeof(struct ip6fl_iter_state));
723 }
724 
725 static const struct file_operations ip6fl_seq_fops = {
726 	.owner		=	THIS_MODULE,
727 	.open		=	ip6fl_seq_open,
728 	.read		=	seq_read,
729 	.llseek		=	seq_lseek,
730 	.release	=	seq_release_net,
731 };
732 
733 static int ip6_flowlabel_proc_init(struct net *net)
734 {
735 	if (!proc_net_fops_create(net, "ip6_flowlabel",
736 				  S_IRUGO, &ip6fl_seq_fops))
737 		return -ENOMEM;
738 	return 0;
739 }
740 
741 static void ip6_flowlabel_proc_fini(struct net *net)
742 {
743 	proc_net_remove(net, "ip6_flowlabel");
744 }
745 #else
746 static inline int ip6_flowlabel_proc_init(struct net *net)
747 {
748 	return 0;
749 }
750 static inline void ip6_flowlabel_proc_fini(struct net *net)
751 {
752 	return ;
753 }
754 #endif
755 
756 static inline void ip6_flowlabel_net_exit(struct net *net)
757 {
758 	ip6_fl_purge(net);
759 	ip6_flowlabel_proc_fini(net);
760 }
761 
762 static struct pernet_operations ip6_flowlabel_net_ops = {
763 	.init = ip6_flowlabel_proc_init,
764 	.exit = ip6_flowlabel_net_exit,
765 };
766 
767 int ip6_flowlabel_init(void)
768 {
769 	return register_pernet_subsys(&ip6_flowlabel_net_ops);
770 }
771 
772 void ip6_flowlabel_cleanup(void)
773 {
774 	del_timer(&ip6_fl_gc_timer);
775 	unregister_pernet_subsys(&ip6_flowlabel_net_ops);
776 }
777