xref: /openbmc/linux/net/ipv6/ip6_flowlabel.c (revision d0b73b48)
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 #include <linux/slab.h>
24 #include <linux/export.h>
25 #include <linux/pid_namespace.h>
26 
27 #include <net/net_namespace.h>
28 #include <net/sock.h>
29 
30 #include <net/ipv6.h>
31 #include <net/ndisc.h>
32 #include <net/protocol.h>
33 #include <net/ip6_route.h>
34 #include <net/addrconf.h>
35 #include <net/rawv6.h>
36 #include <net/icmp.h>
37 #include <net/transp_v6.h>
38 
39 #include <asm/uaccess.h>
40 
41 #define FL_MIN_LINGER	6	/* Minimal linger. It is set to 6sec specified
42 				   in old IPv6 RFC. Well, it was reasonable value.
43 				 */
44 #define FL_MAX_LINGER	60	/* Maximal linger timeout */
45 
46 /* FL hash table */
47 
48 #define FL_MAX_PER_SOCK	32
49 #define FL_MAX_SIZE	4096
50 #define FL_HASH_MASK	255
51 #define FL_HASH(l)	(ntohl(l)&FL_HASH_MASK)
52 
53 static atomic_t fl_size = ATOMIC_INIT(0);
54 static struct ip6_flowlabel *fl_ht[FL_HASH_MASK+1];
55 
56 static void ip6_fl_gc(unsigned long dummy);
57 static DEFINE_TIMER(ip6_fl_gc_timer, ip6_fl_gc, 0, 0);
58 
59 /* FL hash table lock: it protects only of GC */
60 
61 static DEFINE_RWLOCK(ip6_fl_lock);
62 
63 /* Big socket sock */
64 
65 static DEFINE_RWLOCK(ip6_sk_fl_lock);
66 
67 
68 static inline struct ip6_flowlabel *__fl_lookup(struct net *net, __be32 label)
69 {
70 	struct ip6_flowlabel *fl;
71 
72 	for (fl=fl_ht[FL_HASH(label)]; fl; fl = fl->next) {
73 		if (fl->label == label && net_eq(fl->fl_net, net))
74 			return fl;
75 	}
76 	return NULL;
77 }
78 
79 static struct ip6_flowlabel *fl_lookup(struct net *net, __be32 label)
80 {
81 	struct ip6_flowlabel *fl;
82 
83 	read_lock_bh(&ip6_fl_lock);
84 	fl = __fl_lookup(net, label);
85 	if (fl)
86 		atomic_inc(&fl->users);
87 	read_unlock_bh(&ip6_fl_lock);
88 	return fl;
89 }
90 
91 
92 static void fl_free(struct ip6_flowlabel *fl)
93 {
94 	if (fl) {
95 		if (fl->share == IPV6_FL_S_PROCESS)
96 			put_pid(fl->owner.pid);
97 		release_net(fl->fl_net);
98 		kfree(fl->opt);
99 	}
100 	kfree(fl);
101 }
102 
103 static void fl_release(struct ip6_flowlabel *fl)
104 {
105 	write_lock_bh(&ip6_fl_lock);
106 
107 	fl->lastuse = jiffies;
108 	if (atomic_dec_and_test(&fl->users)) {
109 		unsigned long ttd = fl->lastuse + fl->linger;
110 		if (time_after(ttd, fl->expires))
111 			fl->expires = ttd;
112 		ttd = fl->expires;
113 		if (fl->opt && fl->share == IPV6_FL_S_EXCL) {
114 			struct ipv6_txoptions *opt = fl->opt;
115 			fl->opt = NULL;
116 			kfree(opt);
117 		}
118 		if (!timer_pending(&ip6_fl_gc_timer) ||
119 		    time_after(ip6_fl_gc_timer.expires, ttd))
120 			mod_timer(&ip6_fl_gc_timer, ttd);
121 	}
122 	write_unlock_bh(&ip6_fl_lock);
123 }
124 
125 static void ip6_fl_gc(unsigned long dummy)
126 {
127 	int i;
128 	unsigned long now = jiffies;
129 	unsigned long sched = 0;
130 
131 	write_lock(&ip6_fl_lock);
132 
133 	for (i=0; i<=FL_HASH_MASK; i++) {
134 		struct ip6_flowlabel *fl, **flp;
135 		flp = &fl_ht[i];
136 		while ((fl=*flp) != NULL) {
137 			if (atomic_read(&fl->users) == 0) {
138 				unsigned long ttd = fl->lastuse + fl->linger;
139 				if (time_after(ttd, fl->expires))
140 					fl->expires = ttd;
141 				ttd = fl->expires;
142 				if (time_after_eq(now, ttd)) {
143 					*flp = fl->next;
144 					fl_free(fl);
145 					atomic_dec(&fl_size);
146 					continue;
147 				}
148 				if (!sched || time_before(ttd, sched))
149 					sched = ttd;
150 			}
151 			flp = &fl->next;
152 		}
153 	}
154 	if (!sched && atomic_read(&fl_size))
155 		sched = now + FL_MAX_LINGER;
156 	if (sched) {
157 		mod_timer(&ip6_fl_gc_timer, sched);
158 	}
159 	write_unlock(&ip6_fl_lock);
160 }
161 
162 static void __net_exit ip6_fl_purge(struct net *net)
163 {
164 	int i;
165 
166 	write_lock(&ip6_fl_lock);
167 	for (i = 0; i <= FL_HASH_MASK; i++) {
168 		struct ip6_flowlabel *fl, **flp;
169 		flp = &fl_ht[i];
170 		while ((fl = *flp) != NULL) {
171 			if (net_eq(fl->fl_net, net) &&
172 			    atomic_read(&fl->users) == 0) {
173 				*flp = fl->next;
174 				fl_free(fl);
175 				atomic_dec(&fl_size);
176 				continue;
177 			}
178 			flp = &fl->next;
179 		}
180 	}
181 	write_unlock(&ip6_fl_lock);
182 }
183 
184 static struct ip6_flowlabel *fl_intern(struct net *net,
185 				       struct ip6_flowlabel *fl, __be32 label)
186 {
187 	struct ip6_flowlabel *lfl;
188 
189 	fl->label = label & IPV6_FLOWLABEL_MASK;
190 
191 	write_lock_bh(&ip6_fl_lock);
192 	if (label == 0) {
193 		for (;;) {
194 			fl->label = htonl(net_random())&IPV6_FLOWLABEL_MASK;
195 			if (fl->label) {
196 				lfl = __fl_lookup(net, fl->label);
197 				if (lfl == NULL)
198 					break;
199 			}
200 		}
201 	} else {
202 		/*
203 		 * we dropper the ip6_fl_lock, so this entry could reappear
204 		 * and we need to recheck with it.
205 		 *
206 		 * OTOH no need to search the active socket first, like it is
207 		 * done in ipv6_flowlabel_opt - sock is locked, so new entry
208 		 * with the same label can only appear on another sock
209 		 */
210 		lfl = __fl_lookup(net, fl->label);
211 		if (lfl != NULL) {
212 			atomic_inc(&lfl->users);
213 			write_unlock_bh(&ip6_fl_lock);
214 			return lfl;
215 		}
216 	}
217 
218 	fl->lastuse = jiffies;
219 	fl->next = fl_ht[FL_HASH(fl->label)];
220 	fl_ht[FL_HASH(fl->label)] = fl;
221 	atomic_inc(&fl_size);
222 	write_unlock_bh(&ip6_fl_lock);
223 	return NULL;
224 }
225 
226 
227 
228 /* Socket flowlabel lists */
229 
230 struct ip6_flowlabel * fl6_sock_lookup(struct sock *sk, __be32 label)
231 {
232 	struct ipv6_fl_socklist *sfl;
233 	struct ipv6_pinfo *np = inet6_sk(sk);
234 
235 	label &= IPV6_FLOWLABEL_MASK;
236 
237 	read_lock_bh(&ip6_sk_fl_lock);
238 	for (sfl=np->ipv6_fl_list; sfl; sfl = sfl->next) {
239 		struct ip6_flowlabel *fl = sfl->fl;
240 		if (fl->label == label) {
241 			fl->lastuse = jiffies;
242 			atomic_inc(&fl->users);
243 			read_unlock_bh(&ip6_sk_fl_lock);
244 			return fl;
245 		}
246 	}
247 	read_unlock_bh(&ip6_sk_fl_lock);
248 	return NULL;
249 }
250 
251 EXPORT_SYMBOL_GPL(fl6_sock_lookup);
252 
253 void fl6_free_socklist(struct sock *sk)
254 {
255 	struct ipv6_pinfo *np = inet6_sk(sk);
256 	struct ipv6_fl_socklist *sfl;
257 
258 	while ((sfl = np->ipv6_fl_list) != NULL) {
259 		np->ipv6_fl_list = sfl->next;
260 		fl_release(sfl->fl);
261 		kfree(sfl);
262 	}
263 }
264 
265 /* Service routines */
266 
267 
268 /*
269    It is the only difficult place. flowlabel enforces equal headers
270    before and including routing header, however user may supply options
271    following rthdr.
272  */
273 
274 struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions * opt_space,
275 					 struct ip6_flowlabel * fl,
276 					 struct ipv6_txoptions * fopt)
277 {
278 	struct ipv6_txoptions * fl_opt = fl->opt;
279 
280 	if (fopt == NULL || fopt->opt_flen == 0)
281 		return fl_opt;
282 
283 	if (fl_opt != NULL) {
284 		opt_space->hopopt = fl_opt->hopopt;
285 		opt_space->dst0opt = fl_opt->dst0opt;
286 		opt_space->srcrt = fl_opt->srcrt;
287 		opt_space->opt_nflen = fl_opt->opt_nflen;
288 	} else {
289 		if (fopt->opt_nflen == 0)
290 			return fopt;
291 		opt_space->hopopt = NULL;
292 		opt_space->dst0opt = NULL;
293 		opt_space->srcrt = NULL;
294 		opt_space->opt_nflen = 0;
295 	}
296 	opt_space->dst1opt = fopt->dst1opt;
297 	opt_space->opt_flen = fopt->opt_flen;
298 	return opt_space;
299 }
300 EXPORT_SYMBOL_GPL(fl6_merge_options);
301 
302 static unsigned long check_linger(unsigned long ttl)
303 {
304 	if (ttl < FL_MIN_LINGER)
305 		return FL_MIN_LINGER*HZ;
306 	if (ttl > FL_MAX_LINGER && !capable(CAP_NET_ADMIN))
307 		return 0;
308 	return ttl*HZ;
309 }
310 
311 static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned long expires)
312 {
313 	linger = check_linger(linger);
314 	if (!linger)
315 		return -EPERM;
316 	expires = check_linger(expires);
317 	if (!expires)
318 		return -EPERM;
319 	fl->lastuse = jiffies;
320 	if (time_before(fl->linger, linger))
321 		fl->linger = linger;
322 	if (time_before(expires, fl->linger))
323 		expires = fl->linger;
324 	if (time_before(fl->expires, fl->lastuse + expires))
325 		fl->expires = fl->lastuse + expires;
326 	return 0;
327 }
328 
329 static struct ip6_flowlabel *
330 fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq,
331 	  char __user *optval, int optlen, int *err_p)
332 {
333 	struct ip6_flowlabel *fl = NULL;
334 	int olen;
335 	int addr_type;
336 	int err;
337 
338 	olen = optlen - CMSG_ALIGN(sizeof(*freq));
339 	err = -EINVAL;
340 	if (olen > 64 * 1024)
341 		goto done;
342 
343 	err = -ENOMEM;
344 	fl = kzalloc(sizeof(*fl), GFP_KERNEL);
345 	if (fl == NULL)
346 		goto done;
347 
348 	if (olen > 0) {
349 		struct msghdr msg;
350 		struct flowi6 flowi6;
351 		int junk;
352 
353 		err = -ENOMEM;
354 		fl->opt = kmalloc(sizeof(*fl->opt) + olen, GFP_KERNEL);
355 		if (fl->opt == NULL)
356 			goto done;
357 
358 		memset(fl->opt, 0, sizeof(*fl->opt));
359 		fl->opt->tot_len = sizeof(*fl->opt) + olen;
360 		err = -EFAULT;
361 		if (copy_from_user(fl->opt+1, optval+CMSG_ALIGN(sizeof(*freq)), olen))
362 			goto done;
363 
364 		msg.msg_controllen = olen;
365 		msg.msg_control = (void*)(fl->opt+1);
366 		memset(&flowi6, 0, sizeof(flowi6));
367 
368 		err = ip6_datagram_send_ctl(net, sk, &msg, &flowi6, fl->opt,
369 					    &junk, &junk, &junk);
370 		if (err)
371 			goto done;
372 		err = -EINVAL;
373 		if (fl->opt->opt_flen)
374 			goto done;
375 		if (fl->opt->opt_nflen == 0) {
376 			kfree(fl->opt);
377 			fl->opt = NULL;
378 		}
379 	}
380 
381 	fl->fl_net = hold_net(net);
382 	fl->expires = jiffies;
383 	err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
384 	if (err)
385 		goto done;
386 	fl->share = freq->flr_share;
387 	addr_type = ipv6_addr_type(&freq->flr_dst);
388 	if ((addr_type & IPV6_ADDR_MAPPED) ||
389 	    addr_type == IPV6_ADDR_ANY) {
390 		err = -EINVAL;
391 		goto done;
392 	}
393 	fl->dst = freq->flr_dst;
394 	atomic_set(&fl->users, 1);
395 	switch (fl->share) {
396 	case IPV6_FL_S_EXCL:
397 	case IPV6_FL_S_ANY:
398 		break;
399 	case IPV6_FL_S_PROCESS:
400 		fl->owner.pid = get_task_pid(current, PIDTYPE_PID);
401 		break;
402 	case IPV6_FL_S_USER:
403 		fl->owner.uid = current_euid();
404 		break;
405 	default:
406 		err = -EINVAL;
407 		goto done;
408 	}
409 	return fl;
410 
411 done:
412 	fl_free(fl);
413 	*err_p = err;
414 	return NULL;
415 }
416 
417 static int mem_check(struct sock *sk)
418 {
419 	struct ipv6_pinfo *np = inet6_sk(sk);
420 	struct ipv6_fl_socklist *sfl;
421 	int room = FL_MAX_SIZE - atomic_read(&fl_size);
422 	int count = 0;
423 
424 	if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
425 		return 0;
426 
427 	for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next)
428 		count++;
429 
430 	if (room <= 0 ||
431 	    ((count >= FL_MAX_PER_SOCK ||
432 	      (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4) &&
433 	     !capable(CAP_NET_ADMIN)))
434 		return -ENOBUFS;
435 
436 	return 0;
437 }
438 
439 static bool ipv6_hdr_cmp(struct ipv6_opt_hdr *h1, struct ipv6_opt_hdr *h2)
440 {
441 	if (h1 == h2)
442 		return false;
443 	if (h1 == NULL || h2 == NULL)
444 		return true;
445 	if (h1->hdrlen != h2->hdrlen)
446 		return true;
447 	return memcmp(h1+1, h2+1, ((h1->hdrlen+1)<<3) - sizeof(*h1));
448 }
449 
450 static bool ipv6_opt_cmp(struct ipv6_txoptions *o1, struct ipv6_txoptions *o2)
451 {
452 	if (o1 == o2)
453 		return false;
454 	if (o1 == NULL || o2 == NULL)
455 		return true;
456 	if (o1->opt_nflen != o2->opt_nflen)
457 		return true;
458 	if (ipv6_hdr_cmp(o1->hopopt, o2->hopopt))
459 		return true;
460 	if (ipv6_hdr_cmp(o1->dst0opt, o2->dst0opt))
461 		return true;
462 	if (ipv6_hdr_cmp((struct ipv6_opt_hdr *)o1->srcrt, (struct ipv6_opt_hdr *)o2->srcrt))
463 		return true;
464 	return false;
465 }
466 
467 static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
468 		struct ip6_flowlabel *fl)
469 {
470 	write_lock_bh(&ip6_sk_fl_lock);
471 	sfl->fl = fl;
472 	sfl->next = np->ipv6_fl_list;
473 	np->ipv6_fl_list = sfl;
474 	write_unlock_bh(&ip6_sk_fl_lock);
475 }
476 
477 int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
478 {
479 	int uninitialized_var(err);
480 	struct net *net = sock_net(sk);
481 	struct ipv6_pinfo *np = inet6_sk(sk);
482 	struct in6_flowlabel_req freq;
483 	struct ipv6_fl_socklist *sfl1=NULL;
484 	struct ipv6_fl_socklist *sfl, **sflp;
485 	struct ip6_flowlabel *fl, *fl1 = NULL;
486 
487 
488 	if (optlen < sizeof(freq))
489 		return -EINVAL;
490 
491 	if (copy_from_user(&freq, optval, sizeof(freq)))
492 		return -EFAULT;
493 
494 	switch (freq.flr_action) {
495 	case IPV6_FL_A_PUT:
496 		write_lock_bh(&ip6_sk_fl_lock);
497 		for (sflp = &np->ipv6_fl_list; (sfl=*sflp)!=NULL; sflp = &sfl->next) {
498 			if (sfl->fl->label == freq.flr_label) {
499 				if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK))
500 					np->flow_label &= ~IPV6_FLOWLABEL_MASK;
501 				*sflp = sfl->next;
502 				write_unlock_bh(&ip6_sk_fl_lock);
503 				fl_release(sfl->fl);
504 				kfree(sfl);
505 				return 0;
506 			}
507 		}
508 		write_unlock_bh(&ip6_sk_fl_lock);
509 		return -ESRCH;
510 
511 	case IPV6_FL_A_RENEW:
512 		read_lock_bh(&ip6_sk_fl_lock);
513 		for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) {
514 			if (sfl->fl->label == freq.flr_label) {
515 				err = fl6_renew(sfl->fl, freq.flr_linger, freq.flr_expires);
516 				read_unlock_bh(&ip6_sk_fl_lock);
517 				return err;
518 			}
519 		}
520 		read_unlock_bh(&ip6_sk_fl_lock);
521 
522 		if (freq.flr_share == IPV6_FL_S_NONE &&
523 		    ns_capable(net->user_ns, CAP_NET_ADMIN)) {
524 			fl = fl_lookup(net, freq.flr_label);
525 			if (fl) {
526 				err = fl6_renew(fl, freq.flr_linger, freq.flr_expires);
527 				fl_release(fl);
528 				return err;
529 			}
530 		}
531 		return -ESRCH;
532 
533 	case IPV6_FL_A_GET:
534 		if (freq.flr_label & ~IPV6_FLOWLABEL_MASK)
535 			return -EINVAL;
536 
537 		fl = fl_create(net, sk, &freq, optval, optlen, &err);
538 		if (fl == NULL)
539 			return err;
540 		sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
541 
542 		if (freq.flr_label) {
543 			err = -EEXIST;
544 			read_lock_bh(&ip6_sk_fl_lock);
545 			for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) {
546 				if (sfl->fl->label == freq.flr_label) {
547 					if (freq.flr_flags&IPV6_FL_F_EXCL) {
548 						read_unlock_bh(&ip6_sk_fl_lock);
549 						goto done;
550 					}
551 					fl1 = sfl->fl;
552 					atomic_inc(&fl1->users);
553 					break;
554 				}
555 			}
556 			read_unlock_bh(&ip6_sk_fl_lock);
557 
558 			if (fl1 == NULL)
559 				fl1 = fl_lookup(net, freq.flr_label);
560 			if (fl1) {
561 recheck:
562 				err = -EEXIST;
563 				if (freq.flr_flags&IPV6_FL_F_EXCL)
564 					goto release;
565 				err = -EPERM;
566 				if (fl1->share == IPV6_FL_S_EXCL ||
567 				    fl1->share != fl->share ||
568 				    ((fl1->share == IPV6_FL_S_PROCESS) &&
569 				     (fl1->owner.pid == fl->owner.pid)) ||
570 				    ((fl1->share == IPV6_FL_S_USER) &&
571 				     uid_eq(fl1->owner.uid, fl->owner.uid)))
572 					goto release;
573 
574 				err = -EINVAL;
575 				if (!ipv6_addr_equal(&fl1->dst, &fl->dst) ||
576 				    ipv6_opt_cmp(fl1->opt, fl->opt))
577 					goto release;
578 
579 				err = -ENOMEM;
580 				if (sfl1 == NULL)
581 					goto release;
582 				if (fl->linger > fl1->linger)
583 					fl1->linger = fl->linger;
584 				if ((long)(fl->expires - fl1->expires) > 0)
585 					fl1->expires = fl->expires;
586 				fl_link(np, sfl1, fl1);
587 				fl_free(fl);
588 				return 0;
589 
590 release:
591 				fl_release(fl1);
592 				goto done;
593 			}
594 		}
595 		err = -ENOENT;
596 		if (!(freq.flr_flags&IPV6_FL_F_CREATE))
597 			goto done;
598 
599 		err = -ENOMEM;
600 		if (sfl1 == NULL || (err = mem_check(sk)) != 0)
601 			goto done;
602 
603 		fl1 = fl_intern(net, fl, freq.flr_label);
604 		if (fl1 != NULL)
605 			goto recheck;
606 
607 		if (!freq.flr_label) {
608 			if (copy_to_user(&((struct in6_flowlabel_req __user *) optval)->flr_label,
609 					 &fl->label, sizeof(fl->label))) {
610 				/* Intentionally ignore fault. */
611 			}
612 		}
613 
614 		fl_link(np, sfl1, fl);
615 		return 0;
616 
617 	default:
618 		return -EINVAL;
619 	}
620 
621 done:
622 	fl_free(fl);
623 	kfree(sfl1);
624 	return err;
625 }
626 
627 #ifdef CONFIG_PROC_FS
628 
629 struct ip6fl_iter_state {
630 	struct seq_net_private p;
631 	struct pid_namespace *pid_ns;
632 	int bucket;
633 };
634 
635 #define ip6fl_seq_private(seq)	((struct ip6fl_iter_state *)(seq)->private)
636 
637 static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
638 {
639 	struct ip6_flowlabel *fl = NULL;
640 	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
641 	struct net *net = seq_file_net(seq);
642 
643 	for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {
644 		fl = fl_ht[state->bucket];
645 
646 		while (fl && !net_eq(fl->fl_net, net))
647 			fl = fl->next;
648 		if (fl)
649 			break;
650 	}
651 	return fl;
652 }
653 
654 static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl)
655 {
656 	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
657 	struct net *net = seq_file_net(seq);
658 
659 	fl = fl->next;
660 try_again:
661 	while (fl && !net_eq(fl->fl_net, net))
662 		fl = fl->next;
663 
664 	while (!fl) {
665 		if (++state->bucket <= FL_HASH_MASK) {
666 			fl = fl_ht[state->bucket];
667 			goto try_again;
668 		} else
669 			break;
670 	}
671 	return fl;
672 }
673 
674 static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
675 {
676 	struct ip6_flowlabel *fl = ip6fl_get_first(seq);
677 	if (fl)
678 		while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL)
679 			--pos;
680 	return pos ? NULL : fl;
681 }
682 
683 static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
684 	__acquires(ip6_fl_lock)
685 {
686 	read_lock_bh(&ip6_fl_lock);
687 	return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
688 }
689 
690 static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
691 {
692 	struct ip6_flowlabel *fl;
693 
694 	if (v == SEQ_START_TOKEN)
695 		fl = ip6fl_get_first(seq);
696 	else
697 		fl = ip6fl_get_next(seq, v);
698 	++*pos;
699 	return fl;
700 }
701 
702 static void ip6fl_seq_stop(struct seq_file *seq, void *v)
703 	__releases(ip6_fl_lock)
704 {
705 	read_unlock_bh(&ip6_fl_lock);
706 }
707 
708 static int ip6fl_seq_show(struct seq_file *seq, void *v)
709 {
710 	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
711 	if (v == SEQ_START_TOKEN)
712 		seq_printf(seq, "%-5s %-1s %-6s %-6s %-6s %-8s %-32s %s\n",
713 			   "Label", "S", "Owner", "Users", "Linger", "Expires", "Dst", "Opt");
714 	else {
715 		struct ip6_flowlabel *fl = v;
716 		seq_printf(seq,
717 			   "%05X %-1d %-6d %-6d %-6ld %-8ld %pi6 %-4d\n",
718 			   (unsigned int)ntohl(fl->label),
719 			   fl->share,
720 			   ((fl->share == IPV6_FL_S_PROCESS) ?
721 			    pid_nr_ns(fl->owner.pid, state->pid_ns) :
722 			    ((fl->share == IPV6_FL_S_USER) ?
723 			     from_kuid_munged(seq_user_ns(seq), fl->owner.uid) :
724 			     0)),
725 			   atomic_read(&fl->users),
726 			   fl->linger/HZ,
727 			   (long)(fl->expires - jiffies)/HZ,
728 			   &fl->dst,
729 			   fl->opt ? fl->opt->opt_nflen : 0);
730 	}
731 	return 0;
732 }
733 
734 static const struct seq_operations ip6fl_seq_ops = {
735 	.start	=	ip6fl_seq_start,
736 	.next	=	ip6fl_seq_next,
737 	.stop	=	ip6fl_seq_stop,
738 	.show	=	ip6fl_seq_show,
739 };
740 
741 static int ip6fl_seq_open(struct inode *inode, struct file *file)
742 {
743 	struct seq_file *seq;
744 	struct ip6fl_iter_state *state;
745 	int err;
746 
747 	err = seq_open_net(inode, file, &ip6fl_seq_ops,
748 			   sizeof(struct ip6fl_iter_state));
749 
750 	if (!err) {
751 		seq = file->private_data;
752 		state = ip6fl_seq_private(seq);
753 		rcu_read_lock();
754 		state->pid_ns = get_pid_ns(task_active_pid_ns(current));
755 		rcu_read_unlock();
756 	}
757 	return err;
758 }
759 
760 static int ip6fl_seq_release(struct inode *inode, struct file *file)
761 {
762 	struct seq_file *seq = file->private_data;
763 	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
764 	put_pid_ns(state->pid_ns);
765 	return seq_release_net(inode, file);
766 }
767 
768 static const struct file_operations ip6fl_seq_fops = {
769 	.owner		=	THIS_MODULE,
770 	.open		=	ip6fl_seq_open,
771 	.read		=	seq_read,
772 	.llseek		=	seq_lseek,
773 	.release	=	ip6fl_seq_release,
774 };
775 
776 static int __net_init ip6_flowlabel_proc_init(struct net *net)
777 {
778 	if (!proc_net_fops_create(net, "ip6_flowlabel",
779 				  S_IRUGO, &ip6fl_seq_fops))
780 		return -ENOMEM;
781 	return 0;
782 }
783 
784 static void __net_exit ip6_flowlabel_proc_fini(struct net *net)
785 {
786 	proc_net_remove(net, "ip6_flowlabel");
787 }
788 #else
789 static inline int ip6_flowlabel_proc_init(struct net *net)
790 {
791 	return 0;
792 }
793 static inline void ip6_flowlabel_proc_fini(struct net *net)
794 {
795 }
796 #endif
797 
798 static void __net_exit ip6_flowlabel_net_exit(struct net *net)
799 {
800 	ip6_fl_purge(net);
801 	ip6_flowlabel_proc_fini(net);
802 }
803 
804 static struct pernet_operations ip6_flowlabel_net_ops = {
805 	.init = ip6_flowlabel_proc_init,
806 	.exit = ip6_flowlabel_net_exit,
807 };
808 
809 int ip6_flowlabel_init(void)
810 {
811 	return register_pernet_subsys(&ip6_flowlabel_net_ops);
812 }
813 
814 void ip6_flowlabel_cleanup(void)
815 {
816 	del_timer(&ip6_fl_gc_timer);
817 	unregister_pernet_subsys(&ip6_flowlabel_net_ops);
818 }
819