xref: /openbmc/linux/net/ipv6/ip6_flowlabel.c (revision 7dd65feb)
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 && net_eq(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 (net_eq(fl->fl_net, net) &&
167 			    atomic_read(&fl->users) == 0) {
168 				*flp = fl->next;
169 				fl_free(fl);
170 				atomic_dec(&fl_size);
171 				continue;
172 			}
173 			flp = &fl->next;
174 		}
175 	}
176 	write_unlock(&ip6_fl_lock);
177 }
178 
179 static struct ip6_flowlabel *fl_intern(struct net *net,
180 				       struct ip6_flowlabel *fl, __be32 label)
181 {
182 	struct ip6_flowlabel *lfl;
183 
184 	fl->label = label & IPV6_FLOWLABEL_MASK;
185 
186 	write_lock_bh(&ip6_fl_lock);
187 	if (label == 0) {
188 		for (;;) {
189 			fl->label = htonl(net_random())&IPV6_FLOWLABEL_MASK;
190 			if (fl->label) {
191 				lfl = __fl_lookup(net, fl->label);
192 				if (lfl == NULL)
193 					break;
194 			}
195 		}
196 	} else {
197 		/*
198 		 * we dropper the ip6_fl_lock, so this entry could reappear
199 		 * and we need to recheck with it.
200 		 *
201 		 * OTOH no need to search the active socket first, like it is
202 		 * done in ipv6_flowlabel_opt - sock is locked, so new entry
203 		 * with the same label can only appear on another sock
204 		 */
205 		lfl = __fl_lookup(net, fl->label);
206 		if (lfl != NULL) {
207 			atomic_inc(&lfl->users);
208 			write_unlock_bh(&ip6_fl_lock);
209 			return lfl;
210 		}
211 	}
212 
213 	fl->lastuse = jiffies;
214 	fl->next = fl_ht[FL_HASH(fl->label)];
215 	fl_ht[FL_HASH(fl->label)] = fl;
216 	atomic_inc(&fl_size);
217 	write_unlock_bh(&ip6_fl_lock);
218 	return NULL;
219 }
220 
221 
222 
223 /* Socket flowlabel lists */
224 
225 struct ip6_flowlabel * fl6_sock_lookup(struct sock *sk, __be32 label)
226 {
227 	struct ipv6_fl_socklist *sfl;
228 	struct ipv6_pinfo *np = inet6_sk(sk);
229 
230 	label &= IPV6_FLOWLABEL_MASK;
231 
232 	read_lock_bh(&ip6_sk_fl_lock);
233 	for (sfl=np->ipv6_fl_list; sfl; sfl = sfl->next) {
234 		struct ip6_flowlabel *fl = sfl->fl;
235 		if (fl->label == label) {
236 			fl->lastuse = jiffies;
237 			atomic_inc(&fl->users);
238 			read_unlock_bh(&ip6_sk_fl_lock);
239 			return fl;
240 		}
241 	}
242 	read_unlock_bh(&ip6_sk_fl_lock);
243 	return NULL;
244 }
245 
246 EXPORT_SYMBOL_GPL(fl6_sock_lookup);
247 
248 void fl6_free_socklist(struct sock *sk)
249 {
250 	struct ipv6_pinfo *np = inet6_sk(sk);
251 	struct ipv6_fl_socklist *sfl;
252 
253 	while ((sfl = np->ipv6_fl_list) != NULL) {
254 		np->ipv6_fl_list = sfl->next;
255 		fl_release(sfl->fl);
256 		kfree(sfl);
257 	}
258 }
259 
260 /* Service routines */
261 
262 
263 /*
264    It is the only difficult place. flowlabel enforces equal headers
265    before and including routing header, however user may supply options
266    following rthdr.
267  */
268 
269 struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions * opt_space,
270 					 struct ip6_flowlabel * fl,
271 					 struct ipv6_txoptions * fopt)
272 {
273 	struct ipv6_txoptions * fl_opt = fl->opt;
274 
275 	if (fopt == NULL || fopt->opt_flen == 0)
276 		return fl_opt;
277 
278 	if (fl_opt != NULL) {
279 		opt_space->hopopt = fl_opt->hopopt;
280 		opt_space->dst0opt = fl_opt->dst0opt;
281 		opt_space->srcrt = fl_opt->srcrt;
282 		opt_space->opt_nflen = fl_opt->opt_nflen;
283 	} else {
284 		if (fopt->opt_nflen == 0)
285 			return fopt;
286 		opt_space->hopopt = NULL;
287 		opt_space->dst0opt = NULL;
288 		opt_space->srcrt = NULL;
289 		opt_space->opt_nflen = 0;
290 	}
291 	opt_space->dst1opt = fopt->dst1opt;
292 	opt_space->opt_flen = fopt->opt_flen;
293 	return opt_space;
294 }
295 
296 static unsigned long check_linger(unsigned long ttl)
297 {
298 	if (ttl < FL_MIN_LINGER)
299 		return FL_MIN_LINGER*HZ;
300 	if (ttl > FL_MAX_LINGER && !capable(CAP_NET_ADMIN))
301 		return 0;
302 	return ttl*HZ;
303 }
304 
305 static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned long expires)
306 {
307 	linger = check_linger(linger);
308 	if (!linger)
309 		return -EPERM;
310 	expires = check_linger(expires);
311 	if (!expires)
312 		return -EPERM;
313 	fl->lastuse = jiffies;
314 	if (time_before(fl->linger, linger))
315 		fl->linger = linger;
316 	if (time_before(expires, fl->linger))
317 		expires = fl->linger;
318 	if (time_before(fl->expires, fl->lastuse + expires))
319 		fl->expires = fl->lastuse + expires;
320 	return 0;
321 }
322 
323 static struct ip6_flowlabel *
324 fl_create(struct net *net, struct in6_flowlabel_req *freq, char __user *optval,
325 	  int optlen, int *err_p)
326 {
327 	struct ip6_flowlabel *fl = NULL;
328 	int olen;
329 	int addr_type;
330 	int err;
331 
332 	olen = optlen - CMSG_ALIGN(sizeof(*freq));
333 	err = -EINVAL;
334 	if (olen > 64 * 1024)
335 		goto done;
336 
337 	err = -ENOMEM;
338 	fl = kzalloc(sizeof(*fl), GFP_KERNEL);
339 	if (fl == NULL)
340 		goto done;
341 
342 	if (olen > 0) {
343 		struct msghdr msg;
344 		struct flowi flowi;
345 		int junk;
346 
347 		err = -ENOMEM;
348 		fl->opt = kmalloc(sizeof(*fl->opt) + olen, GFP_KERNEL);
349 		if (fl->opt == NULL)
350 			goto done;
351 
352 		memset(fl->opt, 0, sizeof(*fl->opt));
353 		fl->opt->tot_len = sizeof(*fl->opt) + olen;
354 		err = -EFAULT;
355 		if (copy_from_user(fl->opt+1, optval+CMSG_ALIGN(sizeof(*freq)), olen))
356 			goto done;
357 
358 		msg.msg_controllen = olen;
359 		msg.msg_control = (void*)(fl->opt+1);
360 		flowi.oif = 0;
361 
362 		err = datagram_send_ctl(net, &msg, &flowi, fl->opt, &junk, &junk);
363 		if (err)
364 			goto done;
365 		err = -EINVAL;
366 		if (fl->opt->opt_flen)
367 			goto done;
368 		if (fl->opt->opt_nflen == 0) {
369 			kfree(fl->opt);
370 			fl->opt = NULL;
371 		}
372 	}
373 
374 	fl->fl_net = hold_net(net);
375 	fl->expires = jiffies;
376 	err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
377 	if (err)
378 		goto done;
379 	fl->share = freq->flr_share;
380 	addr_type = ipv6_addr_type(&freq->flr_dst);
381 	if ((addr_type & IPV6_ADDR_MAPPED) ||
382 	    addr_type == IPV6_ADDR_ANY) {
383 		err = -EINVAL;
384 		goto done;
385 	}
386 	ipv6_addr_copy(&fl->dst, &freq->flr_dst);
387 	atomic_set(&fl->users, 1);
388 	switch (fl->share) {
389 	case IPV6_FL_S_EXCL:
390 	case IPV6_FL_S_ANY:
391 		break;
392 	case IPV6_FL_S_PROCESS:
393 		fl->owner = current->pid;
394 		break;
395 	case IPV6_FL_S_USER:
396 		fl->owner = current_euid();
397 		break;
398 	default:
399 		err = -EINVAL;
400 		goto done;
401 	}
402 	return fl;
403 
404 done:
405 	fl_free(fl);
406 	*err_p = err;
407 	return NULL;
408 }
409 
410 static int mem_check(struct sock *sk)
411 {
412 	struct ipv6_pinfo *np = inet6_sk(sk);
413 	struct ipv6_fl_socklist *sfl;
414 	int room = FL_MAX_SIZE - atomic_read(&fl_size);
415 	int count = 0;
416 
417 	if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
418 		return 0;
419 
420 	for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next)
421 		count++;
422 
423 	if (room <= 0 ||
424 	    ((count >= FL_MAX_PER_SOCK ||
425 	      (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4) &&
426 	     !capable(CAP_NET_ADMIN)))
427 		return -ENOBUFS;
428 
429 	return 0;
430 }
431 
432 static int ipv6_hdr_cmp(struct ipv6_opt_hdr *h1, struct ipv6_opt_hdr *h2)
433 {
434 	if (h1 == h2)
435 		return 0;
436 	if (h1 == NULL || h2 == NULL)
437 		return 1;
438 	if (h1->hdrlen != h2->hdrlen)
439 		return 1;
440 	return memcmp(h1+1, h2+1, ((h1->hdrlen+1)<<3) - sizeof(*h1));
441 }
442 
443 static int ipv6_opt_cmp(struct ipv6_txoptions *o1, struct ipv6_txoptions *o2)
444 {
445 	if (o1 == o2)
446 		return 0;
447 	if (o1 == NULL || o2 == NULL)
448 		return 1;
449 	if (o1->opt_nflen != o2->opt_nflen)
450 		return 1;
451 	if (ipv6_hdr_cmp(o1->hopopt, o2->hopopt))
452 		return 1;
453 	if (ipv6_hdr_cmp(o1->dst0opt, o2->dst0opt))
454 		return 1;
455 	if (ipv6_hdr_cmp((struct ipv6_opt_hdr *)o1->srcrt, (struct ipv6_opt_hdr *)o2->srcrt))
456 		return 1;
457 	return 0;
458 }
459 
460 static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
461 		struct ip6_flowlabel *fl)
462 {
463 	write_lock_bh(&ip6_sk_fl_lock);
464 	sfl->fl = fl;
465 	sfl->next = np->ipv6_fl_list;
466 	np->ipv6_fl_list = sfl;
467 	write_unlock_bh(&ip6_sk_fl_lock);
468 }
469 
470 int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
471 {
472 	int uninitialized_var(err);
473 	struct net *net = sock_net(sk);
474 	struct ipv6_pinfo *np = inet6_sk(sk);
475 	struct in6_flowlabel_req freq;
476 	struct ipv6_fl_socklist *sfl1=NULL;
477 	struct ipv6_fl_socklist *sfl, **sflp;
478 	struct ip6_flowlabel *fl, *fl1 = NULL;
479 
480 
481 	if (optlen < sizeof(freq))
482 		return -EINVAL;
483 
484 	if (copy_from_user(&freq, optval, sizeof(freq)))
485 		return -EFAULT;
486 
487 	switch (freq.flr_action) {
488 	case IPV6_FL_A_PUT:
489 		write_lock_bh(&ip6_sk_fl_lock);
490 		for (sflp = &np->ipv6_fl_list; (sfl=*sflp)!=NULL; sflp = &sfl->next) {
491 			if (sfl->fl->label == freq.flr_label) {
492 				if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK))
493 					np->flow_label &= ~IPV6_FLOWLABEL_MASK;
494 				*sflp = sfl->next;
495 				write_unlock_bh(&ip6_sk_fl_lock);
496 				fl_release(sfl->fl);
497 				kfree(sfl);
498 				return 0;
499 			}
500 		}
501 		write_unlock_bh(&ip6_sk_fl_lock);
502 		return -ESRCH;
503 
504 	case IPV6_FL_A_RENEW:
505 		read_lock_bh(&ip6_sk_fl_lock);
506 		for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) {
507 			if (sfl->fl->label == freq.flr_label) {
508 				err = fl6_renew(sfl->fl, freq.flr_linger, freq.flr_expires);
509 				read_unlock_bh(&ip6_sk_fl_lock);
510 				return err;
511 			}
512 		}
513 		read_unlock_bh(&ip6_sk_fl_lock);
514 
515 		if (freq.flr_share == IPV6_FL_S_NONE && capable(CAP_NET_ADMIN)) {
516 			fl = fl_lookup(net, freq.flr_label);
517 			if (fl) {
518 				err = fl6_renew(fl, freq.flr_linger, freq.flr_expires);
519 				fl_release(fl);
520 				return err;
521 			}
522 		}
523 		return -ESRCH;
524 
525 	case IPV6_FL_A_GET:
526 		if (freq.flr_label & ~IPV6_FLOWLABEL_MASK)
527 			return -EINVAL;
528 
529 		fl = fl_create(net, &freq, optval, optlen, &err);
530 		if (fl == NULL)
531 			return err;
532 		sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
533 
534 		if (freq.flr_label) {
535 			err = -EEXIST;
536 			read_lock_bh(&ip6_sk_fl_lock);
537 			for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) {
538 				if (sfl->fl->label == freq.flr_label) {
539 					if (freq.flr_flags&IPV6_FL_F_EXCL) {
540 						read_unlock_bh(&ip6_sk_fl_lock);
541 						goto done;
542 					}
543 					fl1 = sfl->fl;
544 					atomic_inc(&fl1->users);
545 					break;
546 				}
547 			}
548 			read_unlock_bh(&ip6_sk_fl_lock);
549 
550 			if (fl1 == NULL)
551 				fl1 = fl_lookup(net, freq.flr_label);
552 			if (fl1) {
553 recheck:
554 				err = -EEXIST;
555 				if (freq.flr_flags&IPV6_FL_F_EXCL)
556 					goto release;
557 				err = -EPERM;
558 				if (fl1->share == IPV6_FL_S_EXCL ||
559 				    fl1->share != fl->share ||
560 				    fl1->owner != fl->owner)
561 					goto release;
562 
563 				err = -EINVAL;
564 				if (!ipv6_addr_equal(&fl1->dst, &fl->dst) ||
565 				    ipv6_opt_cmp(fl1->opt, fl->opt))
566 					goto release;
567 
568 				err = -ENOMEM;
569 				if (sfl1 == NULL)
570 					goto release;
571 				if (fl->linger > fl1->linger)
572 					fl1->linger = fl->linger;
573 				if ((long)(fl->expires - fl1->expires) > 0)
574 					fl1->expires = fl->expires;
575 				fl_link(np, sfl1, fl1);
576 				fl_free(fl);
577 				return 0;
578 
579 release:
580 				fl_release(fl1);
581 				goto done;
582 			}
583 		}
584 		err = -ENOENT;
585 		if (!(freq.flr_flags&IPV6_FL_F_CREATE))
586 			goto done;
587 
588 		err = -ENOMEM;
589 		if (sfl1 == NULL || (err = mem_check(sk)) != 0)
590 			goto done;
591 
592 		fl1 = fl_intern(net, fl, freq.flr_label);
593 		if (fl1 != NULL)
594 			goto recheck;
595 
596 		if (!freq.flr_label) {
597 			if (copy_to_user(&((struct in6_flowlabel_req __user *) optval)->flr_label,
598 					 &fl->label, sizeof(fl->label))) {
599 				/* Intentionally ignore fault. */
600 			}
601 		}
602 
603 		fl_link(np, sfl1, fl);
604 		return 0;
605 
606 	default:
607 		return -EINVAL;
608 	}
609 
610 done:
611 	fl_free(fl);
612 	kfree(sfl1);
613 	return err;
614 }
615 
616 #ifdef CONFIG_PROC_FS
617 
618 struct ip6fl_iter_state {
619 	struct seq_net_private p;
620 	int bucket;
621 };
622 
623 #define ip6fl_seq_private(seq)	((struct ip6fl_iter_state *)(seq)->private)
624 
625 static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
626 {
627 	struct ip6_flowlabel *fl = NULL;
628 	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
629 	struct net *net = seq_file_net(seq);
630 
631 	for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {
632 		fl = fl_ht[state->bucket];
633 
634 		while (fl && !net_eq(fl->fl_net, net))
635 			fl = fl->next;
636 		if (fl)
637 			break;
638 	}
639 	return fl;
640 }
641 
642 static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl)
643 {
644 	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
645 	struct net *net = seq_file_net(seq);
646 
647 	fl = fl->next;
648 try_again:
649 	while (fl && !net_eq(fl->fl_net, net))
650 		fl = fl->next;
651 
652 	while (!fl) {
653 		if (++state->bucket <= FL_HASH_MASK) {
654 			fl = fl_ht[state->bucket];
655 			goto try_again;
656 		} else
657 			break;
658 	}
659 	return fl;
660 }
661 
662 static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
663 {
664 	struct ip6_flowlabel *fl = ip6fl_get_first(seq);
665 	if (fl)
666 		while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL)
667 			--pos;
668 	return pos ? NULL : fl;
669 }
670 
671 static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
672 	__acquires(ip6_fl_lock)
673 {
674 	read_lock_bh(&ip6_fl_lock);
675 	return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
676 }
677 
678 static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
679 {
680 	struct ip6_flowlabel *fl;
681 
682 	if (v == SEQ_START_TOKEN)
683 		fl = ip6fl_get_first(seq);
684 	else
685 		fl = ip6fl_get_next(seq, v);
686 	++*pos;
687 	return fl;
688 }
689 
690 static void ip6fl_seq_stop(struct seq_file *seq, void *v)
691 	__releases(ip6_fl_lock)
692 {
693 	read_unlock_bh(&ip6_fl_lock);
694 }
695 
696 static int ip6fl_seq_show(struct seq_file *seq, void *v)
697 {
698 	if (v == SEQ_START_TOKEN)
699 		seq_printf(seq, "%-5s %-1s %-6s %-6s %-6s %-8s %-32s %s\n",
700 			   "Label", "S", "Owner", "Users", "Linger", "Expires", "Dst", "Opt");
701 	else {
702 		struct ip6_flowlabel *fl = v;
703 		seq_printf(seq,
704 			   "%05X %-1d %-6d %-6d %-6ld %-8ld %pi6 %-4d\n",
705 			   (unsigned)ntohl(fl->label),
706 			   fl->share,
707 			   (unsigned)fl->owner,
708 			   atomic_read(&fl->users),
709 			   fl->linger/HZ,
710 			   (long)(fl->expires - jiffies)/HZ,
711 			   &fl->dst,
712 			   fl->opt ? fl->opt->opt_nflen : 0);
713 	}
714 	return 0;
715 }
716 
717 static const struct seq_operations ip6fl_seq_ops = {
718 	.start	=	ip6fl_seq_start,
719 	.next	=	ip6fl_seq_next,
720 	.stop	=	ip6fl_seq_stop,
721 	.show	=	ip6fl_seq_show,
722 };
723 
724 static int ip6fl_seq_open(struct inode *inode, struct file *file)
725 {
726 	return seq_open_net(inode, file, &ip6fl_seq_ops,
727 			    sizeof(struct ip6fl_iter_state));
728 }
729 
730 static const struct file_operations ip6fl_seq_fops = {
731 	.owner		=	THIS_MODULE,
732 	.open		=	ip6fl_seq_open,
733 	.read		=	seq_read,
734 	.llseek		=	seq_lseek,
735 	.release	=	seq_release_net,
736 };
737 
738 static int ip6_flowlabel_proc_init(struct net *net)
739 {
740 	if (!proc_net_fops_create(net, "ip6_flowlabel",
741 				  S_IRUGO, &ip6fl_seq_fops))
742 		return -ENOMEM;
743 	return 0;
744 }
745 
746 static void ip6_flowlabel_proc_fini(struct net *net)
747 {
748 	proc_net_remove(net, "ip6_flowlabel");
749 }
750 #else
751 static inline int ip6_flowlabel_proc_init(struct net *net)
752 {
753 	return 0;
754 }
755 static inline void ip6_flowlabel_proc_fini(struct net *net)
756 {
757 	return ;
758 }
759 #endif
760 
761 static inline void ip6_flowlabel_net_exit(struct net *net)
762 {
763 	ip6_fl_purge(net);
764 	ip6_flowlabel_proc_fini(net);
765 }
766 
767 static struct pernet_operations ip6_flowlabel_net_ops = {
768 	.init = ip6_flowlabel_proc_init,
769 	.exit = ip6_flowlabel_net_exit,
770 };
771 
772 int ip6_flowlabel_init(void)
773 {
774 	return register_pernet_subsys(&ip6_flowlabel_net_ops);
775 }
776 
777 void ip6_flowlabel_cleanup(void)
778 {
779 	del_timer(&ip6_fl_gc_timer);
780 	unregister_pernet_subsys(&ip6_flowlabel_net_ops);
781 }
782