xref: /openbmc/linux/net/ipv6/ip6_flowlabel.c (revision 4c5c496a)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *	ip6_flowlabel.c		IPv6 flowlabel manager.
4  *
5  *	Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6  */
7 
8 #include <linux/capability.h>
9 #include <linux/errno.h>
10 #include <linux/types.h>
11 #include <linux/socket.h>
12 #include <linux/net.h>
13 #include <linux/netdevice.h>
14 #include <linux/in6.h>
15 #include <linux/proc_fs.h>
16 #include <linux/seq_file.h>
17 #include <linux/slab.h>
18 #include <linux/export.h>
19 #include <linux/pid_namespace.h>
20 #include <linux/jump_label_ratelimit.h>
21 
22 #include <net/net_namespace.h>
23 #include <net/sock.h>
24 
25 #include <net/ipv6.h>
26 #include <net/rawv6.h>
27 #include <net/transp_v6.h>
28 
29 #include <linux/uaccess.h>
30 
31 #define FL_MIN_LINGER	6	/* Minimal linger. It is set to 6sec specified
32 				   in old IPv6 RFC. Well, it was reasonable value.
33 				 */
34 #define FL_MAX_LINGER	150	/* Maximal linger timeout */
35 
36 /* FL hash table */
37 
38 #define FL_MAX_PER_SOCK	32
39 #define FL_MAX_SIZE	4096
40 #define FL_HASH_MASK	255
41 #define FL_HASH(l)	(ntohl(l)&FL_HASH_MASK)
42 
43 static atomic_t fl_size = ATOMIC_INIT(0);
44 static struct ip6_flowlabel __rcu *fl_ht[FL_HASH_MASK+1];
45 
46 static void ip6_fl_gc(struct timer_list *unused);
47 static DEFINE_TIMER(ip6_fl_gc_timer, ip6_fl_gc);
48 
49 /* FL hash table lock: it protects only of GC */
50 
51 static DEFINE_SPINLOCK(ip6_fl_lock);
52 
53 /* Big socket sock */
54 
55 static DEFINE_SPINLOCK(ip6_sk_fl_lock);
56 
57 DEFINE_STATIC_KEY_DEFERRED_FALSE(ipv6_flowlabel_exclusive, HZ);
58 EXPORT_SYMBOL(ipv6_flowlabel_exclusive);
59 
60 #define for_each_fl_rcu(hash, fl)				\
61 	for (fl = rcu_dereference(fl_ht[(hash)]);		\
62 	     fl != NULL;					\
63 	     fl = rcu_dereference(fl->next))
64 #define for_each_fl_continue_rcu(fl)				\
65 	for (fl = rcu_dereference(fl->next);			\
66 	     fl != NULL;					\
67 	     fl = rcu_dereference(fl->next))
68 
69 #define for_each_sk_fl_rcu(np, sfl)				\
70 	for (sfl = rcu_dereference(np->ipv6_fl_list);	\
71 	     sfl != NULL;					\
72 	     sfl = rcu_dereference(sfl->next))
73 
__fl_lookup(struct net * net,__be32 label)74 static inline struct ip6_flowlabel *__fl_lookup(struct net *net, __be32 label)
75 {
76 	struct ip6_flowlabel *fl;
77 
78 	for_each_fl_rcu(FL_HASH(label), fl) {
79 		if (fl->label == label && net_eq(fl->fl_net, net))
80 			return fl;
81 	}
82 	return NULL;
83 }
84 
fl_lookup(struct net * net,__be32 label)85 static struct ip6_flowlabel *fl_lookup(struct net *net, __be32 label)
86 {
87 	struct ip6_flowlabel *fl;
88 
89 	rcu_read_lock();
90 	fl = __fl_lookup(net, label);
91 	if (fl && !atomic_inc_not_zero(&fl->users))
92 		fl = NULL;
93 	rcu_read_unlock();
94 	return fl;
95 }
96 
fl_shared_exclusive(struct ip6_flowlabel * fl)97 static bool fl_shared_exclusive(struct ip6_flowlabel *fl)
98 {
99 	return fl->share == IPV6_FL_S_EXCL ||
100 	       fl->share == IPV6_FL_S_PROCESS ||
101 	       fl->share == IPV6_FL_S_USER;
102 }
103 
fl_free_rcu(struct rcu_head * head)104 static void fl_free_rcu(struct rcu_head *head)
105 {
106 	struct ip6_flowlabel *fl = container_of(head, struct ip6_flowlabel, rcu);
107 
108 	if (fl->share == IPV6_FL_S_PROCESS)
109 		put_pid(fl->owner.pid);
110 	kfree(fl->opt);
111 	kfree(fl);
112 }
113 
114 
fl_free(struct ip6_flowlabel * fl)115 static void fl_free(struct ip6_flowlabel *fl)
116 {
117 	if (!fl)
118 		return;
119 
120 	if (fl_shared_exclusive(fl) || fl->opt)
121 		static_branch_slow_dec_deferred(&ipv6_flowlabel_exclusive);
122 
123 	call_rcu(&fl->rcu, fl_free_rcu);
124 }
125 
fl_release(struct ip6_flowlabel * fl)126 static void fl_release(struct ip6_flowlabel *fl)
127 {
128 	spin_lock_bh(&ip6_fl_lock);
129 
130 	fl->lastuse = jiffies;
131 	if (atomic_dec_and_test(&fl->users)) {
132 		unsigned long ttd = fl->lastuse + fl->linger;
133 		if (time_after(ttd, fl->expires))
134 			fl->expires = ttd;
135 		ttd = fl->expires;
136 		if (fl->opt && fl->share == IPV6_FL_S_EXCL) {
137 			struct ipv6_txoptions *opt = fl->opt;
138 			fl->opt = NULL;
139 			kfree(opt);
140 		}
141 		if (!timer_pending(&ip6_fl_gc_timer) ||
142 		    time_after(ip6_fl_gc_timer.expires, ttd))
143 			mod_timer(&ip6_fl_gc_timer, ttd);
144 	}
145 	spin_unlock_bh(&ip6_fl_lock);
146 }
147 
ip6_fl_gc(struct timer_list * unused)148 static void ip6_fl_gc(struct timer_list *unused)
149 {
150 	int i;
151 	unsigned long now = jiffies;
152 	unsigned long sched = 0;
153 
154 	spin_lock(&ip6_fl_lock);
155 
156 	for (i = 0; i <= FL_HASH_MASK; i++) {
157 		struct ip6_flowlabel *fl;
158 		struct ip6_flowlabel __rcu **flp;
159 
160 		flp = &fl_ht[i];
161 		while ((fl = rcu_dereference_protected(*flp,
162 						       lockdep_is_held(&ip6_fl_lock))) != NULL) {
163 			if (atomic_read(&fl->users) == 0) {
164 				unsigned long ttd = fl->lastuse + fl->linger;
165 				if (time_after(ttd, fl->expires))
166 					fl->expires = ttd;
167 				ttd = fl->expires;
168 				if (time_after_eq(now, ttd)) {
169 					*flp = fl->next;
170 					fl_free(fl);
171 					atomic_dec(&fl_size);
172 					continue;
173 				}
174 				if (!sched || time_before(ttd, sched))
175 					sched = ttd;
176 			}
177 			flp = &fl->next;
178 		}
179 	}
180 	if (!sched && atomic_read(&fl_size))
181 		sched = now + FL_MAX_LINGER;
182 	if (sched) {
183 		mod_timer(&ip6_fl_gc_timer, sched);
184 	}
185 	spin_unlock(&ip6_fl_lock);
186 }
187 
ip6_fl_purge(struct net * net)188 static void __net_exit ip6_fl_purge(struct net *net)
189 {
190 	int i;
191 
192 	spin_lock_bh(&ip6_fl_lock);
193 	for (i = 0; i <= FL_HASH_MASK; i++) {
194 		struct ip6_flowlabel *fl;
195 		struct ip6_flowlabel __rcu **flp;
196 
197 		flp = &fl_ht[i];
198 		while ((fl = rcu_dereference_protected(*flp,
199 						       lockdep_is_held(&ip6_fl_lock))) != NULL) {
200 			if (net_eq(fl->fl_net, net) &&
201 			    atomic_read(&fl->users) == 0) {
202 				*flp = fl->next;
203 				fl_free(fl);
204 				atomic_dec(&fl_size);
205 				continue;
206 			}
207 			flp = &fl->next;
208 		}
209 	}
210 	spin_unlock_bh(&ip6_fl_lock);
211 }
212 
fl_intern(struct net * net,struct ip6_flowlabel * fl,__be32 label)213 static struct ip6_flowlabel *fl_intern(struct net *net,
214 				       struct ip6_flowlabel *fl, __be32 label)
215 {
216 	struct ip6_flowlabel *lfl;
217 
218 	fl->label = label & IPV6_FLOWLABEL_MASK;
219 
220 	rcu_read_lock();
221 	spin_lock_bh(&ip6_fl_lock);
222 	if (label == 0) {
223 		for (;;) {
224 			fl->label = htonl(get_random_u32())&IPV6_FLOWLABEL_MASK;
225 			if (fl->label) {
226 				lfl = __fl_lookup(net, fl->label);
227 				if (!lfl)
228 					break;
229 			}
230 		}
231 	} else {
232 		/*
233 		 * we dropper the ip6_fl_lock, so this entry could reappear
234 		 * and we need to recheck with it.
235 		 *
236 		 * OTOH no need to search the active socket first, like it is
237 		 * done in ipv6_flowlabel_opt - sock is locked, so new entry
238 		 * with the same label can only appear on another sock
239 		 */
240 		lfl = __fl_lookup(net, fl->label);
241 		if (lfl) {
242 			atomic_inc(&lfl->users);
243 			spin_unlock_bh(&ip6_fl_lock);
244 			rcu_read_unlock();
245 			return lfl;
246 		}
247 	}
248 
249 	fl->lastuse = jiffies;
250 	fl->next = fl_ht[FL_HASH(fl->label)];
251 	rcu_assign_pointer(fl_ht[FL_HASH(fl->label)], fl);
252 	atomic_inc(&fl_size);
253 	spin_unlock_bh(&ip6_fl_lock);
254 	rcu_read_unlock();
255 	return NULL;
256 }
257 
258 
259 
260 /* Socket flowlabel lists */
261 
__fl6_sock_lookup(struct sock * sk,__be32 label)262 struct ip6_flowlabel *__fl6_sock_lookup(struct sock *sk, __be32 label)
263 {
264 	struct ipv6_fl_socklist *sfl;
265 	struct ipv6_pinfo *np = inet6_sk(sk);
266 
267 	label &= IPV6_FLOWLABEL_MASK;
268 
269 	rcu_read_lock();
270 	for_each_sk_fl_rcu(np, sfl) {
271 		struct ip6_flowlabel *fl = sfl->fl;
272 
273 		if (fl->label == label && atomic_inc_not_zero(&fl->users)) {
274 			fl->lastuse = jiffies;
275 			rcu_read_unlock();
276 			return fl;
277 		}
278 	}
279 	rcu_read_unlock();
280 	return NULL;
281 }
282 EXPORT_SYMBOL_GPL(__fl6_sock_lookup);
283 
fl6_free_socklist(struct sock * sk)284 void fl6_free_socklist(struct sock *sk)
285 {
286 	struct ipv6_pinfo *np = inet6_sk(sk);
287 	struct ipv6_fl_socklist *sfl;
288 
289 	if (!rcu_access_pointer(np->ipv6_fl_list))
290 		return;
291 
292 	spin_lock_bh(&ip6_sk_fl_lock);
293 	while ((sfl = rcu_dereference_protected(np->ipv6_fl_list,
294 						lockdep_is_held(&ip6_sk_fl_lock))) != NULL) {
295 		np->ipv6_fl_list = sfl->next;
296 		spin_unlock_bh(&ip6_sk_fl_lock);
297 
298 		fl_release(sfl->fl);
299 		kfree_rcu(sfl, rcu);
300 
301 		spin_lock_bh(&ip6_sk_fl_lock);
302 	}
303 	spin_unlock_bh(&ip6_sk_fl_lock);
304 }
305 
306 /* Service routines */
307 
308 
309 /*
310    It is the only difficult place. flowlabel enforces equal headers
311    before and including routing header, however user may supply options
312    following rthdr.
313  */
314 
fl6_merge_options(struct ipv6_txoptions * opt_space,struct ip6_flowlabel * fl,struct ipv6_txoptions * fopt)315 struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions *opt_space,
316 					 struct ip6_flowlabel *fl,
317 					 struct ipv6_txoptions *fopt)
318 {
319 	struct ipv6_txoptions *fl_opt = fl->opt;
320 
321 	if (!fopt || fopt->opt_flen == 0)
322 		return fl_opt;
323 
324 	if (fl_opt) {
325 		opt_space->hopopt = fl_opt->hopopt;
326 		opt_space->dst0opt = fl_opt->dst0opt;
327 		opt_space->srcrt = fl_opt->srcrt;
328 		opt_space->opt_nflen = fl_opt->opt_nflen;
329 	} else {
330 		if (fopt->opt_nflen == 0)
331 			return fopt;
332 		opt_space->hopopt = NULL;
333 		opt_space->dst0opt = NULL;
334 		opt_space->srcrt = NULL;
335 		opt_space->opt_nflen = 0;
336 	}
337 	opt_space->dst1opt = fopt->dst1opt;
338 	opt_space->opt_flen = fopt->opt_flen;
339 	opt_space->tot_len = fopt->tot_len;
340 	return opt_space;
341 }
342 EXPORT_SYMBOL_GPL(fl6_merge_options);
343 
check_linger(unsigned long ttl)344 static unsigned long check_linger(unsigned long ttl)
345 {
346 	if (ttl < FL_MIN_LINGER)
347 		return FL_MIN_LINGER*HZ;
348 	if (ttl > FL_MAX_LINGER && !capable(CAP_NET_ADMIN))
349 		return 0;
350 	return ttl*HZ;
351 }
352 
fl6_renew(struct ip6_flowlabel * fl,unsigned long linger,unsigned long expires)353 static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned long expires)
354 {
355 	linger = check_linger(linger);
356 	if (!linger)
357 		return -EPERM;
358 	expires = check_linger(expires);
359 	if (!expires)
360 		return -EPERM;
361 
362 	spin_lock_bh(&ip6_fl_lock);
363 	fl->lastuse = jiffies;
364 	if (time_before(fl->linger, linger))
365 		fl->linger = linger;
366 	if (time_before(expires, fl->linger))
367 		expires = fl->linger;
368 	if (time_before(fl->expires, fl->lastuse + expires))
369 		fl->expires = fl->lastuse + expires;
370 	spin_unlock_bh(&ip6_fl_lock);
371 
372 	return 0;
373 }
374 
375 static struct ip6_flowlabel *
fl_create(struct net * net,struct sock * sk,struct in6_flowlabel_req * freq,sockptr_t optval,int optlen,int * err_p)376 fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq,
377 	  sockptr_t optval, int optlen, int *err_p)
378 {
379 	struct ip6_flowlabel *fl = NULL;
380 	int olen;
381 	int addr_type;
382 	int err;
383 
384 	olen = optlen - CMSG_ALIGN(sizeof(*freq));
385 	err = -EINVAL;
386 	if (olen > 64 * 1024)
387 		goto done;
388 
389 	err = -ENOMEM;
390 	fl = kzalloc(sizeof(*fl), GFP_KERNEL);
391 	if (!fl)
392 		goto done;
393 
394 	if (olen > 0) {
395 		struct msghdr msg;
396 		struct flowi6 flowi6;
397 		struct ipcm6_cookie ipc6;
398 
399 		err = -ENOMEM;
400 		fl->opt = kmalloc(sizeof(*fl->opt) + olen, GFP_KERNEL);
401 		if (!fl->opt)
402 			goto done;
403 
404 		memset(fl->opt, 0, sizeof(*fl->opt));
405 		fl->opt->tot_len = sizeof(*fl->opt) + olen;
406 		err = -EFAULT;
407 		if (copy_from_sockptr_offset(fl->opt + 1, optval,
408 				CMSG_ALIGN(sizeof(*freq)), olen))
409 			goto done;
410 
411 		msg.msg_controllen = olen;
412 		msg.msg_control = (void *)(fl->opt+1);
413 		memset(&flowi6, 0, sizeof(flowi6));
414 
415 		ipc6.opt = fl->opt;
416 		err = ip6_datagram_send_ctl(net, sk, &msg, &flowi6, &ipc6);
417 		if (err)
418 			goto done;
419 		err = -EINVAL;
420 		if (fl->opt->opt_flen)
421 			goto done;
422 		if (fl->opt->opt_nflen == 0) {
423 			kfree(fl->opt);
424 			fl->opt = NULL;
425 		}
426 	}
427 
428 	fl->fl_net = net;
429 	fl->expires = jiffies;
430 	err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
431 	if (err)
432 		goto done;
433 	fl->share = freq->flr_share;
434 	addr_type = ipv6_addr_type(&freq->flr_dst);
435 	if ((addr_type & IPV6_ADDR_MAPPED) ||
436 	    addr_type == IPV6_ADDR_ANY) {
437 		err = -EINVAL;
438 		goto done;
439 	}
440 	fl->dst = freq->flr_dst;
441 	atomic_set(&fl->users, 1);
442 	switch (fl->share) {
443 	case IPV6_FL_S_EXCL:
444 	case IPV6_FL_S_ANY:
445 		break;
446 	case IPV6_FL_S_PROCESS:
447 		fl->owner.pid = get_task_pid(current, PIDTYPE_PID);
448 		break;
449 	case IPV6_FL_S_USER:
450 		fl->owner.uid = current_euid();
451 		break;
452 	default:
453 		err = -EINVAL;
454 		goto done;
455 	}
456 	if (fl_shared_exclusive(fl) || fl->opt) {
457 		WRITE_ONCE(sock_net(sk)->ipv6.flowlabel_has_excl, 1);
458 		static_branch_deferred_inc(&ipv6_flowlabel_exclusive);
459 	}
460 	return fl;
461 
462 done:
463 	if (fl) {
464 		kfree(fl->opt);
465 		kfree(fl);
466 	}
467 	*err_p = err;
468 	return NULL;
469 }
470 
mem_check(struct sock * sk)471 static int mem_check(struct sock *sk)
472 {
473 	struct ipv6_pinfo *np = inet6_sk(sk);
474 	struct ipv6_fl_socklist *sfl;
475 	int room = FL_MAX_SIZE - atomic_read(&fl_size);
476 	int count = 0;
477 
478 	if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
479 		return 0;
480 
481 	rcu_read_lock();
482 	for_each_sk_fl_rcu(np, sfl)
483 		count++;
484 	rcu_read_unlock();
485 
486 	if (room <= 0 ||
487 	    ((count >= FL_MAX_PER_SOCK ||
488 	      (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4) &&
489 	     !capable(CAP_NET_ADMIN)))
490 		return -ENOBUFS;
491 
492 	return 0;
493 }
494 
fl_link(struct ipv6_pinfo * np,struct ipv6_fl_socklist * sfl,struct ip6_flowlabel * fl)495 static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
496 		struct ip6_flowlabel *fl)
497 {
498 	spin_lock_bh(&ip6_sk_fl_lock);
499 	sfl->fl = fl;
500 	sfl->next = np->ipv6_fl_list;
501 	rcu_assign_pointer(np->ipv6_fl_list, sfl);
502 	spin_unlock_bh(&ip6_sk_fl_lock);
503 }
504 
ipv6_flowlabel_opt_get(struct sock * sk,struct in6_flowlabel_req * freq,int flags)505 int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq,
506 			   int flags)
507 {
508 	struct ipv6_pinfo *np = inet6_sk(sk);
509 	struct ipv6_fl_socklist *sfl;
510 
511 	if (flags & IPV6_FL_F_REMOTE) {
512 		freq->flr_label = np->rcv_flowinfo & IPV6_FLOWLABEL_MASK;
513 		return 0;
514 	}
515 
516 	if (np->repflow) {
517 		freq->flr_label = np->flow_label;
518 		return 0;
519 	}
520 
521 	rcu_read_lock();
522 
523 	for_each_sk_fl_rcu(np, sfl) {
524 		if (sfl->fl->label == (np->flow_label & IPV6_FLOWLABEL_MASK)) {
525 			spin_lock_bh(&ip6_fl_lock);
526 			freq->flr_label = sfl->fl->label;
527 			freq->flr_dst = sfl->fl->dst;
528 			freq->flr_share = sfl->fl->share;
529 			freq->flr_expires = (sfl->fl->expires - jiffies) / HZ;
530 			freq->flr_linger = sfl->fl->linger / HZ;
531 
532 			spin_unlock_bh(&ip6_fl_lock);
533 			rcu_read_unlock();
534 			return 0;
535 		}
536 	}
537 	rcu_read_unlock();
538 
539 	return -ENOENT;
540 }
541 
542 #define socklist_dereference(__sflp) \
543 	rcu_dereference_protected(__sflp, lockdep_is_held(&ip6_sk_fl_lock))
544 
ipv6_flowlabel_put(struct sock * sk,struct in6_flowlabel_req * freq)545 static int ipv6_flowlabel_put(struct sock *sk, struct in6_flowlabel_req *freq)
546 {
547 	struct ipv6_pinfo *np = inet6_sk(sk);
548 	struct ipv6_fl_socklist __rcu **sflp;
549 	struct ipv6_fl_socklist *sfl;
550 
551 	if (freq->flr_flags & IPV6_FL_F_REFLECT) {
552 		if (sk->sk_protocol != IPPROTO_TCP)
553 			return -ENOPROTOOPT;
554 		if (!np->repflow)
555 			return -ESRCH;
556 		np->flow_label = 0;
557 		np->repflow = 0;
558 		return 0;
559 	}
560 
561 	spin_lock_bh(&ip6_sk_fl_lock);
562 	for (sflp = &np->ipv6_fl_list;
563 	     (sfl = socklist_dereference(*sflp)) != NULL;
564 	     sflp = &sfl->next) {
565 		if (sfl->fl->label == freq->flr_label)
566 			goto found;
567 	}
568 	spin_unlock_bh(&ip6_sk_fl_lock);
569 	return -ESRCH;
570 found:
571 	if (freq->flr_label == (np->flow_label & IPV6_FLOWLABEL_MASK))
572 		np->flow_label &= ~IPV6_FLOWLABEL_MASK;
573 	*sflp = sfl->next;
574 	spin_unlock_bh(&ip6_sk_fl_lock);
575 	fl_release(sfl->fl);
576 	kfree_rcu(sfl, rcu);
577 	return 0;
578 }
579 
ipv6_flowlabel_renew(struct sock * sk,struct in6_flowlabel_req * freq)580 static int ipv6_flowlabel_renew(struct sock *sk, struct in6_flowlabel_req *freq)
581 {
582 	struct ipv6_pinfo *np = inet6_sk(sk);
583 	struct net *net = sock_net(sk);
584 	struct ipv6_fl_socklist *sfl;
585 	int err;
586 
587 	rcu_read_lock();
588 	for_each_sk_fl_rcu(np, sfl) {
589 		if (sfl->fl->label == freq->flr_label) {
590 			err = fl6_renew(sfl->fl, freq->flr_linger,
591 					freq->flr_expires);
592 			rcu_read_unlock();
593 			return err;
594 		}
595 	}
596 	rcu_read_unlock();
597 
598 	if (freq->flr_share == IPV6_FL_S_NONE &&
599 	    ns_capable(net->user_ns, CAP_NET_ADMIN)) {
600 		struct ip6_flowlabel *fl = fl_lookup(net, freq->flr_label);
601 
602 		if (fl) {
603 			err = fl6_renew(fl, freq->flr_linger,
604 					freq->flr_expires);
605 			fl_release(fl);
606 			return err;
607 		}
608 	}
609 	return -ESRCH;
610 }
611 
ipv6_flowlabel_get(struct sock * sk,struct in6_flowlabel_req * freq,sockptr_t optval,int optlen)612 static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,
613 		sockptr_t optval, int optlen)
614 {
615 	struct ipv6_fl_socklist *sfl, *sfl1 = NULL;
616 	struct ip6_flowlabel *fl, *fl1 = NULL;
617 	struct ipv6_pinfo *np = inet6_sk(sk);
618 	struct net *net = sock_net(sk);
619 	int err;
620 
621 	if (freq->flr_flags & IPV6_FL_F_REFLECT) {
622 		if (net->ipv6.sysctl.flowlabel_consistency) {
623 			net_info_ratelimited("Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable\n");
624 			return -EPERM;
625 		}
626 
627 		if (sk->sk_protocol != IPPROTO_TCP)
628 			return -ENOPROTOOPT;
629 		np->repflow = 1;
630 		return 0;
631 	}
632 
633 	if (freq->flr_label & ~IPV6_FLOWLABEL_MASK)
634 		return -EINVAL;
635 	if (net->ipv6.sysctl.flowlabel_state_ranges &&
636 	    (freq->flr_label & IPV6_FLOWLABEL_STATELESS_FLAG))
637 		return -ERANGE;
638 
639 	fl = fl_create(net, sk, freq, optval, optlen, &err);
640 	if (!fl)
641 		return err;
642 
643 	sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
644 
645 	if (freq->flr_label) {
646 		err = -EEXIST;
647 		rcu_read_lock();
648 		for_each_sk_fl_rcu(np, sfl) {
649 			if (sfl->fl->label == freq->flr_label) {
650 				if (freq->flr_flags & IPV6_FL_F_EXCL) {
651 					rcu_read_unlock();
652 					goto done;
653 				}
654 				fl1 = sfl->fl;
655 				if (!atomic_inc_not_zero(&fl1->users))
656 					fl1 = NULL;
657 				break;
658 			}
659 		}
660 		rcu_read_unlock();
661 
662 		if (!fl1)
663 			fl1 = fl_lookup(net, freq->flr_label);
664 		if (fl1) {
665 recheck:
666 			err = -EEXIST;
667 			if (freq->flr_flags&IPV6_FL_F_EXCL)
668 				goto release;
669 			err = -EPERM;
670 			if (fl1->share == IPV6_FL_S_EXCL ||
671 			    fl1->share != fl->share ||
672 			    ((fl1->share == IPV6_FL_S_PROCESS) &&
673 			     (fl1->owner.pid != fl->owner.pid)) ||
674 			    ((fl1->share == IPV6_FL_S_USER) &&
675 			     !uid_eq(fl1->owner.uid, fl->owner.uid)))
676 				goto release;
677 
678 			err = -ENOMEM;
679 			if (!sfl1)
680 				goto release;
681 			if (fl->linger > fl1->linger)
682 				fl1->linger = fl->linger;
683 			if ((long)(fl->expires - fl1->expires) > 0)
684 				fl1->expires = fl->expires;
685 			fl_link(np, sfl1, fl1);
686 			fl_free(fl);
687 			return 0;
688 
689 release:
690 			fl_release(fl1);
691 			goto done;
692 		}
693 	}
694 	err = -ENOENT;
695 	if (!(freq->flr_flags & IPV6_FL_F_CREATE))
696 		goto done;
697 
698 	err = -ENOMEM;
699 	if (!sfl1)
700 		goto done;
701 
702 	err = mem_check(sk);
703 	if (err != 0)
704 		goto done;
705 
706 	fl1 = fl_intern(net, fl, freq->flr_label);
707 	if (fl1)
708 		goto recheck;
709 
710 	if (!freq->flr_label) {
711 		size_t offset = offsetof(struct in6_flowlabel_req, flr_label);
712 
713 		if (copy_to_sockptr_offset(optval, offset, &fl->label,
714 				sizeof(fl->label))) {
715 			/* Intentionally ignore fault. */
716 		}
717 	}
718 
719 	fl_link(np, sfl1, fl);
720 	return 0;
721 done:
722 	fl_free(fl);
723 	kfree(sfl1);
724 	return err;
725 }
726 
ipv6_flowlabel_opt(struct sock * sk,sockptr_t optval,int optlen)727 int ipv6_flowlabel_opt(struct sock *sk, sockptr_t optval, int optlen)
728 {
729 	struct in6_flowlabel_req freq;
730 
731 	if (optlen < sizeof(freq))
732 		return -EINVAL;
733 	if (copy_from_sockptr(&freq, optval, sizeof(freq)))
734 		return -EFAULT;
735 
736 	switch (freq.flr_action) {
737 	case IPV6_FL_A_PUT:
738 		return ipv6_flowlabel_put(sk, &freq);
739 	case IPV6_FL_A_RENEW:
740 		return ipv6_flowlabel_renew(sk, &freq);
741 	case IPV6_FL_A_GET:
742 		return ipv6_flowlabel_get(sk, &freq, optval, optlen);
743 	default:
744 		return -EINVAL;
745 	}
746 }
747 
748 #ifdef CONFIG_PROC_FS
749 
750 struct ip6fl_iter_state {
751 	struct seq_net_private p;
752 	struct pid_namespace *pid_ns;
753 	int bucket;
754 };
755 
756 #define ip6fl_seq_private(seq)	((struct ip6fl_iter_state *)(seq)->private)
757 
ip6fl_get_first(struct seq_file * seq)758 static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
759 {
760 	struct ip6_flowlabel *fl = NULL;
761 	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
762 	struct net *net = seq_file_net(seq);
763 
764 	for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {
765 		for_each_fl_rcu(state->bucket, fl) {
766 			if (net_eq(fl->fl_net, net))
767 				goto out;
768 		}
769 	}
770 	fl = NULL;
771 out:
772 	return fl;
773 }
774 
ip6fl_get_next(struct seq_file * seq,struct ip6_flowlabel * fl)775 static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl)
776 {
777 	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
778 	struct net *net = seq_file_net(seq);
779 
780 	for_each_fl_continue_rcu(fl) {
781 		if (net_eq(fl->fl_net, net))
782 			goto out;
783 	}
784 
785 try_again:
786 	if (++state->bucket <= FL_HASH_MASK) {
787 		for_each_fl_rcu(state->bucket, fl) {
788 			if (net_eq(fl->fl_net, net))
789 				goto out;
790 		}
791 		goto try_again;
792 	}
793 	fl = NULL;
794 
795 out:
796 	return fl;
797 }
798 
ip6fl_get_idx(struct seq_file * seq,loff_t pos)799 static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
800 {
801 	struct ip6_flowlabel *fl = ip6fl_get_first(seq);
802 	if (fl)
803 		while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL)
804 			--pos;
805 	return pos ? NULL : fl;
806 }
807 
ip6fl_seq_start(struct seq_file * seq,loff_t * pos)808 static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
809 	__acquires(RCU)
810 {
811 	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
812 
813 	state->pid_ns = proc_pid_ns(file_inode(seq->file)->i_sb);
814 
815 	rcu_read_lock();
816 	return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
817 }
818 
ip6fl_seq_next(struct seq_file * seq,void * v,loff_t * pos)819 static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
820 {
821 	struct ip6_flowlabel *fl;
822 
823 	if (v == SEQ_START_TOKEN)
824 		fl = ip6fl_get_first(seq);
825 	else
826 		fl = ip6fl_get_next(seq, v);
827 	++*pos;
828 	return fl;
829 }
830 
ip6fl_seq_stop(struct seq_file * seq,void * v)831 static void ip6fl_seq_stop(struct seq_file *seq, void *v)
832 	__releases(RCU)
833 {
834 	rcu_read_unlock();
835 }
836 
ip6fl_seq_show(struct seq_file * seq,void * v)837 static int ip6fl_seq_show(struct seq_file *seq, void *v)
838 {
839 	struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
840 	if (v == SEQ_START_TOKEN) {
841 		seq_puts(seq, "Label S Owner  Users  Linger Expires  Dst                              Opt\n");
842 	} else {
843 		struct ip6_flowlabel *fl = v;
844 		seq_printf(seq,
845 			   "%05X %-1d %-6d %-6d %-6ld %-8ld %pi6 %-4d\n",
846 			   (unsigned int)ntohl(fl->label),
847 			   fl->share,
848 			   ((fl->share == IPV6_FL_S_PROCESS) ?
849 			    pid_nr_ns(fl->owner.pid, state->pid_ns) :
850 			    ((fl->share == IPV6_FL_S_USER) ?
851 			     from_kuid_munged(seq_user_ns(seq), fl->owner.uid) :
852 			     0)),
853 			   atomic_read(&fl->users),
854 			   fl->linger/HZ,
855 			   (long)(fl->expires - jiffies)/HZ,
856 			   &fl->dst,
857 			   fl->opt ? fl->opt->opt_nflen : 0);
858 	}
859 	return 0;
860 }
861 
862 static const struct seq_operations ip6fl_seq_ops = {
863 	.start	=	ip6fl_seq_start,
864 	.next	=	ip6fl_seq_next,
865 	.stop	=	ip6fl_seq_stop,
866 	.show	=	ip6fl_seq_show,
867 };
868 
ip6_flowlabel_proc_init(struct net * net)869 static int __net_init ip6_flowlabel_proc_init(struct net *net)
870 {
871 	if (!proc_create_net("ip6_flowlabel", 0444, net->proc_net,
872 			&ip6fl_seq_ops, sizeof(struct ip6fl_iter_state)))
873 		return -ENOMEM;
874 	return 0;
875 }
876 
ip6_flowlabel_proc_fini(struct net * net)877 static void __net_exit ip6_flowlabel_proc_fini(struct net *net)
878 {
879 	remove_proc_entry("ip6_flowlabel", net->proc_net);
880 }
881 #else
ip6_flowlabel_proc_init(struct net * net)882 static inline int ip6_flowlabel_proc_init(struct net *net)
883 {
884 	return 0;
885 }
ip6_flowlabel_proc_fini(struct net * net)886 static inline void ip6_flowlabel_proc_fini(struct net *net)
887 {
888 }
889 #endif
890 
ip6_flowlabel_net_exit(struct net * net)891 static void __net_exit ip6_flowlabel_net_exit(struct net *net)
892 {
893 	ip6_fl_purge(net);
894 	ip6_flowlabel_proc_fini(net);
895 }
896 
897 static struct pernet_operations ip6_flowlabel_net_ops = {
898 	.init = ip6_flowlabel_proc_init,
899 	.exit = ip6_flowlabel_net_exit,
900 };
901 
ip6_flowlabel_init(void)902 int ip6_flowlabel_init(void)
903 {
904 	return register_pernet_subsys(&ip6_flowlabel_net_ops);
905 }
906 
ip6_flowlabel_cleanup(void)907 void ip6_flowlabel_cleanup(void)
908 {
909 	static_key_deferred_flush(&ipv6_flowlabel_exclusive);
910 	del_timer(&ip6_fl_gc_timer);
911 	unregister_pernet_subsys(&ip6_flowlabel_net_ops);
912 }
913