xref: /openbmc/linux/net/core/sysctl_net_core.c (revision fadbafc1) 
1 // SPDX-License-Identifier: GPL-2.0
2 /* -*- linux-c -*-
3  * sysctl_net_core.c: sysctl interface to net core subsystem.
4  *
5  * Begun April 1, 1996, Mike Shaver.
6  * Added /proc/sys/net/core directory entry (empty =) ). [MS]
7  */
8 
9 #include <linux/filter.h>
10 #include <linux/mm.h>
11 #include <linux/sysctl.h>
12 #include <linux/module.h>
13 #include <linux/socket.h>
14 #include <linux/netdevice.h>
15 #include <linux/ratelimit.h>
16 #include <linux/vmalloc.h>
17 #include <linux/init.h>
18 #include <linux/slab.h>
19 
20 #include <net/ip.h>
21 #include <net/sock.h>
22 #include <net/net_ratelimit.h>
23 #include <net/busy_poll.h>
24 #include <net/pkt_sched.h>
25 
26 #include "dev.h"
27 
28 static int int_3600 = 3600;
29 static int min_sndbuf = SOCK_MIN_SNDBUF;
30 static int min_rcvbuf = SOCK_MIN_RCVBUF;
31 static int max_skb_frags = MAX_SKB_FRAGS;
32 
33 static int net_msg_warn;	/* Unused, but still a sysctl */
34 
35 int sysctl_fb_tunnels_only_for_init_net __read_mostly = 0;
36 EXPORT_SYMBOL(sysctl_fb_tunnels_only_for_init_net);
37 
38 /* 0 - Keep current behavior:
39  *     IPv4: inherit all current settings from init_net
40  *     IPv6: reset all settings to default
41  * 1 - Both inherit all current settings from init_net
42  * 2 - Both reset all settings to default
43  * 3 - Both inherit all settings from current netns
44  */
45 int sysctl_devconf_inherit_init_net __read_mostly;
46 EXPORT_SYMBOL(sysctl_devconf_inherit_init_net);
47 
48 #ifdef CONFIG_RPS
49 static int rps_sock_flow_sysctl(struct ctl_table *table, int write,
50 				void *buffer, size_t *lenp, loff_t *ppos)
51 {
52 	unsigned int orig_size, size;
53 	int ret, i;
54 	struct ctl_table tmp = {
55 		.data = &size,
56 		.maxlen = sizeof(size),
57 		.mode = table->mode
58 	};
59 	struct rps_sock_flow_table *orig_sock_table, *sock_table;
60 	static DEFINE_MUTEX(sock_flow_mutex);
61 
62 	mutex_lock(&sock_flow_mutex);
63 
64 	orig_sock_table = rcu_dereference_protected(rps_sock_flow_table,
65 					lockdep_is_held(&sock_flow_mutex));
66 	size = orig_size = orig_sock_table ? orig_sock_table->mask + 1 : 0;
67 
68 	ret = proc_dointvec(&tmp, write, buffer, lenp, ppos);
69 
70 	if (write) {
71 		if (size) {
72 			if (size > 1<<29) {
73 				/* Enforce limit to prevent overflow */
74 				mutex_unlock(&sock_flow_mutex);
75 				return -EINVAL;
76 			}
77 			size = roundup_pow_of_two(size);
78 			if (size != orig_size) {
79 				sock_table =
80 				    vmalloc(RPS_SOCK_FLOW_TABLE_SIZE(size));
81 				if (!sock_table) {
82 					mutex_unlock(&sock_flow_mutex);
83 					return -ENOMEM;
84 				}
85 				rps_cpu_mask = roundup_pow_of_two(nr_cpu_ids) - 1;
86 				sock_table->mask = size - 1;
87 			} else
88 				sock_table = orig_sock_table;
89 
90 			for (i = 0; i < size; i++)
91 				sock_table->ents[i] = RPS_NO_CPU;
92 		} else
93 			sock_table = NULL;
94 
95 		if (sock_table != orig_sock_table) {
96 			rcu_assign_pointer(rps_sock_flow_table, sock_table);
97 			if (sock_table) {
98 				static_branch_inc(&rps_needed);
99 				static_branch_inc(&rfs_needed);
100 			}
101 			if (orig_sock_table) {
102 				static_branch_dec(&rps_needed);
103 				static_branch_dec(&rfs_needed);
104 				kvfree_rcu(orig_sock_table);
105 			}
106 		}
107 	}
108 
109 	mutex_unlock(&sock_flow_mutex);
110 
111 	return ret;
112 }
113 #endif /* CONFIG_RPS */
114 
115 #ifdef CONFIG_NET_FLOW_LIMIT
116 static DEFINE_MUTEX(flow_limit_update_mutex);
117 
118 static int flow_limit_cpu_sysctl(struct ctl_table *table, int write,
119 				 void *buffer, size_t *lenp, loff_t *ppos)
120 {
121 	struct sd_flow_limit *cur;
122 	struct softnet_data *sd;
123 	cpumask_var_t mask;
124 	int i, len, ret = 0;
125 
126 	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
127 		return -ENOMEM;
128 
129 	if (write) {
130 		ret = cpumask_parse(buffer, mask);
131 		if (ret)
132 			goto done;
133 
134 		mutex_lock(&flow_limit_update_mutex);
135 		len = sizeof(*cur) + netdev_flow_limit_table_len;
136 		for_each_possible_cpu(i) {
137 			sd = &per_cpu(softnet_data, i);
138 			cur = rcu_dereference_protected(sd->flow_limit,
139 				     lockdep_is_held(&flow_limit_update_mutex));
140 			if (cur && !cpumask_test_cpu(i, mask)) {
141 				RCU_INIT_POINTER(sd->flow_limit, NULL);
142 				kfree_rcu(cur);
143 			} else if (!cur && cpumask_test_cpu(i, mask)) {
144 				cur = kzalloc_node(len, GFP_KERNEL,
145 						   cpu_to_node(i));
146 				if (!cur) {
147 					/* not unwinding previous changes */
148 					ret = -ENOMEM;
149 					goto write_unlock;
150 				}
151 				cur->num_buckets = netdev_flow_limit_table_len;
152 				rcu_assign_pointer(sd->flow_limit, cur);
153 			}
154 		}
155 write_unlock:
156 		mutex_unlock(&flow_limit_update_mutex);
157 	} else {
158 		char kbuf[128];
159 
160 		if (*ppos || !*lenp) {
161 			*lenp = 0;
162 			goto done;
163 		}
164 
165 		cpumask_clear(mask);
166 		rcu_read_lock();
167 		for_each_possible_cpu(i) {
168 			sd = &per_cpu(softnet_data, i);
169 			if (rcu_dereference(sd->flow_limit))
170 				cpumask_set_cpu(i, mask);
171 		}
172 		rcu_read_unlock();
173 
174 		len = min(sizeof(kbuf) - 1, *lenp);
175 		len = scnprintf(kbuf, len, "%*pb", cpumask_pr_args(mask));
176 		if (!len) {
177 			*lenp = 0;
178 			goto done;
179 		}
180 		if (len < *lenp)
181 			kbuf[len++] = '\n';
182 		memcpy(buffer, kbuf, len);
183 		*lenp = len;
184 		*ppos += len;
185 	}
186 
187 done:
188 	free_cpumask_var(mask);
189 	return ret;
190 }
191 
192 static int flow_limit_table_len_sysctl(struct ctl_table *table, int write,
193 				       void *buffer, size_t *lenp, loff_t *ppos)
194 {
195 	unsigned int old, *ptr;
196 	int ret;
197 
198 	mutex_lock(&flow_limit_update_mutex);
199 
200 	ptr = table->data;
201 	old = *ptr;
202 	ret = proc_dointvec(table, write, buffer, lenp, ppos);
203 	if (!ret && write && !is_power_of_2(*ptr)) {
204 		*ptr = old;
205 		ret = -EINVAL;
206 	}
207 
208 	mutex_unlock(&flow_limit_update_mutex);
209 	return ret;
210 }
211 #endif /* CONFIG_NET_FLOW_LIMIT */
212 
213 #ifdef CONFIG_NET_SCHED
214 static int set_default_qdisc(struct ctl_table *table, int write,
215 			     void *buffer, size_t *lenp, loff_t *ppos)
216 {
217 	char id[IFNAMSIZ];
218 	struct ctl_table tbl = {
219 		.data = id,
220 		.maxlen = IFNAMSIZ,
221 	};
222 	int ret;
223 
224 	qdisc_get_default(id, IFNAMSIZ);
225 
226 	ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
227 	if (write && ret == 0)
228 		ret = qdisc_set_default(id);
229 	return ret;
230 }
231 #endif
232 
233 static int proc_do_dev_weight(struct ctl_table *table, int write,
234 			   void *buffer, size_t *lenp, loff_t *ppos)
235 {
236 	static DEFINE_MUTEX(dev_weight_mutex);
237 	int ret, weight;
238 
239 	mutex_lock(&dev_weight_mutex);
240 	ret = proc_dointvec(table, write, buffer, lenp, ppos);
241 	if (!ret && write) {
242 		weight = READ_ONCE(weight_p);
243 		WRITE_ONCE(dev_rx_weight, weight * dev_weight_rx_bias);
244 		WRITE_ONCE(dev_tx_weight, weight * dev_weight_tx_bias);
245 	}
246 	mutex_unlock(&dev_weight_mutex);
247 
248 	return ret;
249 }
250 
251 static int proc_do_rss_key(struct ctl_table *table, int write,
252 			   void *buffer, size_t *lenp, loff_t *ppos)
253 {
254 	struct ctl_table fake_table;
255 	char buf[NETDEV_RSS_KEY_LEN * 3];
256 
257 	snprintf(buf, sizeof(buf), "%*phC", NETDEV_RSS_KEY_LEN, netdev_rss_key);
258 	fake_table.data = buf;
259 	fake_table.maxlen = sizeof(buf);
260 	return proc_dostring(&fake_table, write, buffer, lenp, ppos);
261 }
262 
263 #ifdef CONFIG_BPF_JIT
264 static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write,
265 					   void *buffer, size_t *lenp,
266 					   loff_t *ppos)
267 {
268 	int ret, jit_enable = *(int *)table->data;
269 	int min = *(int *)table->extra1;
270 	int max = *(int *)table->extra2;
271 	struct ctl_table tmp = *table;
272 
273 	if (write && !capable(CAP_SYS_ADMIN))
274 		return -EPERM;
275 
276 	tmp.data = &jit_enable;
277 	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
278 	if (write && !ret) {
279 		if (jit_enable < 2 ||
280 		    (jit_enable == 2 && bpf_dump_raw_ok(current_cred()))) {
281 			*(int *)table->data = jit_enable;
282 			if (jit_enable == 2)
283 				pr_warn("bpf_jit_enable = 2 was set! NEVER use this in production, only for JIT debugging!\n");
284 		} else {
285 			ret = -EPERM;
286 		}
287 	}
288 
289 	if (write && ret && min == max)
290 		pr_info_once("CONFIG_BPF_JIT_ALWAYS_ON is enabled, bpf_jit_enable is permanently set to 1.\n");
291 
292 	return ret;
293 }
294 
295 # ifdef CONFIG_HAVE_EBPF_JIT
296 static int
297 proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
298 				    void *buffer, size_t *lenp, loff_t *ppos)
299 {
300 	if (!capable(CAP_SYS_ADMIN))
301 		return -EPERM;
302 
303 	return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
304 }
305 # endif /* CONFIG_HAVE_EBPF_JIT */
306 
307 static int
308 proc_dolongvec_minmax_bpf_restricted(struct ctl_table *table, int write,
309 				     void *buffer, size_t *lenp, loff_t *ppos)
310 {
311 	if (!capable(CAP_SYS_ADMIN))
312 		return -EPERM;
313 
314 	return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
315 }
316 #endif
317 
318 static struct ctl_table net_core_table[] = {
319 	{
320 		.procname	= "wmem_max",
321 		.data		= &sysctl_wmem_max,
322 		.maxlen		= sizeof(int),
323 		.mode		= 0644,
324 		.proc_handler	= proc_dointvec_minmax,
325 		.extra1		= &min_sndbuf,
326 	},
327 	{
328 		.procname	= "rmem_max",
329 		.data		= &sysctl_rmem_max,
330 		.maxlen		= sizeof(int),
331 		.mode		= 0644,
332 		.proc_handler	= proc_dointvec_minmax,
333 		.extra1		= &min_rcvbuf,
334 	},
335 	{
336 		.procname	= "wmem_default",
337 		.data		= &sysctl_wmem_default,
338 		.maxlen		= sizeof(int),
339 		.mode		= 0644,
340 		.proc_handler	= proc_dointvec_minmax,
341 		.extra1		= &min_sndbuf,
342 	},
343 	{
344 		.procname	= "rmem_default",
345 		.data		= &sysctl_rmem_default,
346 		.maxlen		= sizeof(int),
347 		.mode		= 0644,
348 		.proc_handler	= proc_dointvec_minmax,
349 		.extra1		= &min_rcvbuf,
350 	},
351 	{
352 		.procname	= "dev_weight",
353 		.data		= &weight_p,
354 		.maxlen		= sizeof(int),
355 		.mode		= 0644,
356 		.proc_handler	= proc_do_dev_weight,
357 	},
358 	{
359 		.procname	= "dev_weight_rx_bias",
360 		.data		= &dev_weight_rx_bias,
361 		.maxlen		= sizeof(int),
362 		.mode		= 0644,
363 		.proc_handler	= proc_do_dev_weight,
364 	},
365 	{
366 		.procname	= "dev_weight_tx_bias",
367 		.data		= &dev_weight_tx_bias,
368 		.maxlen		= sizeof(int),
369 		.mode		= 0644,
370 		.proc_handler	= proc_do_dev_weight,
371 	},
372 	{
373 		.procname	= "netdev_max_backlog",
374 		.data		= &netdev_max_backlog,
375 		.maxlen		= sizeof(int),
376 		.mode		= 0644,
377 		.proc_handler	= proc_dointvec
378 	},
379 	{
380 		.procname	= "netdev_rss_key",
381 		.data		= &netdev_rss_key,
382 		.maxlen		= sizeof(int),
383 		.mode		= 0444,
384 		.proc_handler	= proc_do_rss_key,
385 	},
386 #ifdef CONFIG_BPF_JIT
387 	{
388 		.procname	= "bpf_jit_enable",
389 		.data		= &bpf_jit_enable,
390 		.maxlen		= sizeof(int),
391 		.mode		= 0644,
392 		.proc_handler	= proc_dointvec_minmax_bpf_enable,
393 # ifdef CONFIG_BPF_JIT_ALWAYS_ON
394 		.extra1		= SYSCTL_ONE,
395 		.extra2		= SYSCTL_ONE,
396 # else
397 		.extra1		= SYSCTL_ZERO,
398 		.extra2		= SYSCTL_TWO,
399 # endif
400 	},
401 # ifdef CONFIG_HAVE_EBPF_JIT
402 	{
403 		.procname	= "bpf_jit_harden",
404 		.data		= &bpf_jit_harden,
405 		.maxlen		= sizeof(int),
406 		.mode		= 0600,
407 		.proc_handler	= proc_dointvec_minmax_bpf_restricted,
408 		.extra1		= SYSCTL_ZERO,
409 		.extra2		= SYSCTL_TWO,
410 	},
411 	{
412 		.procname	= "bpf_jit_kallsyms",
413 		.data		= &bpf_jit_kallsyms,
414 		.maxlen		= sizeof(int),
415 		.mode		= 0600,
416 		.proc_handler	= proc_dointvec_minmax_bpf_restricted,
417 		.extra1		= SYSCTL_ZERO,
418 		.extra2		= SYSCTL_ONE,
419 	},
420 # endif
421 	{
422 		.procname	= "bpf_jit_limit",
423 		.data		= &bpf_jit_limit,
424 		.maxlen		= sizeof(long),
425 		.mode		= 0600,
426 		.proc_handler	= proc_dolongvec_minmax_bpf_restricted,
427 		.extra1		= SYSCTL_LONG_ONE,
428 		.extra2		= &bpf_jit_limit_max,
429 	},
430 #endif
431 	{
432 		.procname	= "netdev_tstamp_prequeue",
433 		.data		= &netdev_tstamp_prequeue,
434 		.maxlen		= sizeof(int),
435 		.mode		= 0644,
436 		.proc_handler	= proc_dointvec
437 	},
438 	{
439 		.procname	= "message_cost",
440 		.data		= &net_ratelimit_state.interval,
441 		.maxlen		= sizeof(int),
442 		.mode		= 0644,
443 		.proc_handler	= proc_dointvec_jiffies,
444 	},
445 	{
446 		.procname	= "message_burst",
447 		.data		= &net_ratelimit_state.burst,
448 		.maxlen		= sizeof(int),
449 		.mode		= 0644,
450 		.proc_handler	= proc_dointvec,
451 	},
452 	{
453 		.procname	= "optmem_max",
454 		.data		= &sysctl_optmem_max,
455 		.maxlen		= sizeof(int),
456 		.mode		= 0644,
457 		.proc_handler	= proc_dointvec
458 	},
459 	{
460 		.procname	= "tstamp_allow_data",
461 		.data		= &sysctl_tstamp_allow_data,
462 		.maxlen		= sizeof(int),
463 		.mode		= 0644,
464 		.proc_handler	= proc_dointvec_minmax,
465 		.extra1		= SYSCTL_ZERO,
466 		.extra2		= SYSCTL_ONE
467 	},
468 #ifdef CONFIG_RPS
469 	{
470 		.procname	= "rps_sock_flow_entries",
471 		.maxlen		= sizeof(int),
472 		.mode		= 0644,
473 		.proc_handler	= rps_sock_flow_sysctl
474 	},
475 #endif
476 #ifdef CONFIG_NET_FLOW_LIMIT
477 	{
478 		.procname	= "flow_limit_cpu_bitmap",
479 		.mode		= 0644,
480 		.proc_handler	= flow_limit_cpu_sysctl
481 	},
482 	{
483 		.procname	= "flow_limit_table_len",
484 		.data		= &netdev_flow_limit_table_len,
485 		.maxlen		= sizeof(int),
486 		.mode		= 0644,
487 		.proc_handler	= flow_limit_table_len_sysctl
488 	},
489 #endif /* CONFIG_NET_FLOW_LIMIT */
490 #ifdef CONFIG_NET_RX_BUSY_POLL
491 	{
492 		.procname	= "busy_poll",
493 		.data		= &sysctl_net_busy_poll,
494 		.maxlen		= sizeof(unsigned int),
495 		.mode		= 0644,
496 		.proc_handler	= proc_dointvec_minmax,
497 		.extra1		= SYSCTL_ZERO,
498 	},
499 	{
500 		.procname	= "busy_read",
501 		.data		= &sysctl_net_busy_read,
502 		.maxlen		= sizeof(unsigned int),
503 		.mode		= 0644,
504 		.proc_handler	= proc_dointvec_minmax,
505 		.extra1		= SYSCTL_ZERO,
506 	},
507 #endif
508 #ifdef CONFIG_NET_SCHED
509 	{
510 		.procname	= "default_qdisc",
511 		.mode		= 0644,
512 		.maxlen		= IFNAMSIZ,
513 		.proc_handler	= set_default_qdisc
514 	},
515 #endif
516 	{
517 		.procname	= "netdev_budget",
518 		.data		= &netdev_budget,
519 		.maxlen		= sizeof(int),
520 		.mode		= 0644,
521 		.proc_handler	= proc_dointvec
522 	},
523 	{
524 		.procname	= "warnings",
525 		.data		= &net_msg_warn,
526 		.maxlen		= sizeof(int),
527 		.mode		= 0644,
528 		.proc_handler	= proc_dointvec
529 	},
530 	{
531 		.procname	= "max_skb_frags",
532 		.data		= &sysctl_max_skb_frags,
533 		.maxlen		= sizeof(int),
534 		.mode		= 0644,
535 		.proc_handler	= proc_dointvec_minmax,
536 		.extra1		= SYSCTL_ONE,
537 		.extra2		= &max_skb_frags,
538 	},
539 	{
540 		.procname	= "netdev_budget_usecs",
541 		.data		= &netdev_budget_usecs,
542 		.maxlen		= sizeof(unsigned int),
543 		.mode		= 0644,
544 		.proc_handler	= proc_dointvec_minmax,
545 		.extra1		= SYSCTL_ZERO,
546 	},
547 	{
548 		.procname	= "fb_tunnels_only_for_init_net",
549 		.data		= &sysctl_fb_tunnels_only_for_init_net,
550 		.maxlen		= sizeof(int),
551 		.mode		= 0644,
552 		.proc_handler	= proc_dointvec_minmax,
553 		.extra1		= SYSCTL_ZERO,
554 		.extra2		= SYSCTL_TWO,
555 	},
556 	{
557 		.procname	= "devconf_inherit_init_net",
558 		.data		= &sysctl_devconf_inherit_init_net,
559 		.maxlen		= sizeof(int),
560 		.mode		= 0644,
561 		.proc_handler	= proc_dointvec_minmax,
562 		.extra1		= SYSCTL_ZERO,
563 		.extra2		= SYSCTL_THREE,
564 	},
565 	{
566 		.procname	= "high_order_alloc_disable",
567 		.data		= &net_high_order_alloc_disable_key.key,
568 		.maxlen         = sizeof(net_high_order_alloc_disable_key),
569 		.mode		= 0644,
570 		.proc_handler	= proc_do_static_key,
571 	},
572 	{
573 		.procname	= "gro_normal_batch",
574 		.data		= &gro_normal_batch,
575 		.maxlen		= sizeof(unsigned int),
576 		.mode		= 0644,
577 		.proc_handler	= proc_dointvec_minmax,
578 		.extra1		= SYSCTL_ONE,
579 	},
580 	{
581 		.procname	= "netdev_unregister_timeout_secs",
582 		.data		= &netdev_unregister_timeout_secs,
583 		.maxlen		= sizeof(unsigned int),
584 		.mode		= 0644,
585 		.proc_handler	= proc_dointvec_minmax,
586 		.extra1		= SYSCTL_ONE,
587 		.extra2		= &int_3600,
588 	},
589 	{
590 		.procname	= "skb_defer_max",
591 		.data		= &sysctl_skb_defer_max,
592 		.maxlen		= sizeof(unsigned int),
593 		.mode		= 0644,
594 		.proc_handler	= proc_dointvec_minmax,
595 		.extra1		= SYSCTL_ZERO,
596 	},
597 	{ }
598 };
599 
600 static struct ctl_table netns_core_table[] = {
601 	{
602 		.procname	= "somaxconn",
603 		.data		= &init_net.core.sysctl_somaxconn,
604 		.maxlen		= sizeof(int),
605 		.mode		= 0644,
606 		.extra1		= SYSCTL_ZERO,
607 		.proc_handler	= proc_dointvec_minmax
608 	},
609 	{
610 		.procname	= "txrehash",
611 		.data		= &init_net.core.sysctl_txrehash,
612 		.maxlen		= sizeof(u8),
613 		.mode		= 0644,
614 		.extra1		= SYSCTL_ZERO,
615 		.extra2		= SYSCTL_ONE,
616 		.proc_handler	= proc_dou8vec_minmax,
617 	},
618 	{ }
619 };
620 
621 static int __init fb_tunnels_only_for_init_net_sysctl_setup(char *str)
622 {
623 	/* fallback tunnels for initns only */
624 	if (!strncmp(str, "initns", 6))
625 		sysctl_fb_tunnels_only_for_init_net = 1;
626 	/* no fallback tunnels anywhere */
627 	else if (!strncmp(str, "none", 4))
628 		sysctl_fb_tunnels_only_for_init_net = 2;
629 
630 	return 1;
631 }
632 __setup("fb_tunnels=", fb_tunnels_only_for_init_net_sysctl_setup);
633 
634 static __net_init int sysctl_core_net_init(struct net *net)
635 {
636 	struct ctl_table *tbl, *tmp;
637 
638 	tbl = netns_core_table;
639 	if (!net_eq(net, &init_net)) {
640 		tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);
641 		if (tbl == NULL)
642 			goto err_dup;
643 
644 		for (tmp = tbl; tmp->procname; tmp++)
645 			tmp->data += (char *)net - (char *)&init_net;
646 
647 		/* Don't export any sysctls to unprivileged users */
648 		if (net->user_ns != &init_user_ns) {
649 			tbl[0].procname = NULL;
650 		}
651 	}
652 
653 	net->core.sysctl_hdr = register_net_sysctl(net, "net/core", tbl);
654 	if (net->core.sysctl_hdr == NULL)
655 		goto err_reg;
656 
657 	return 0;
658 
659 err_reg:
660 	if (tbl != netns_core_table)
661 		kfree(tbl);
662 err_dup:
663 	return -ENOMEM;
664 }
665 
666 static __net_exit void sysctl_core_net_exit(struct net *net)
667 {
668 	struct ctl_table *tbl;
669 
670 	tbl = net->core.sysctl_hdr->ctl_table_arg;
671 	unregister_net_sysctl_table(net->core.sysctl_hdr);
672 	BUG_ON(tbl == netns_core_table);
673 	kfree(tbl);
674 }
675 
676 static __net_initdata struct pernet_operations sysctl_core_ops = {
677 	.init = sysctl_core_net_init,
678 	.exit = sysctl_core_net_exit,
679 };
680 
681 static __init int sysctl_core_init(void)
682 {
683 	register_net_sysctl(&init_net, "net/core", net_core_table);
684 	return register_pernet_subsys(&sysctl_core_ops);
685 }
686 
687 fs_initcall(sysctl_core_init);
688