xref: /linux/net/ipv4/sysctl_net_ipv4.c (revision 995231c820e3bd3633cb38bf4ea6f2541e1da331)
1 /*
2  * sysctl_net_ipv4.c: sysctl interface to net IPV4 subsystem.
3  *
4  * Begun April 1, 1996, Mike Shaver.
5  * Added /proc/sys/net/ipv4 directory entry (empty =) ). [MS]
6  */
7 
8 #include <linux/mm.h>
9 #include <linux/module.h>
10 #include <linux/sysctl.h>
11 #include <linux/igmp.h>
12 #include <linux/inetdevice.h>
13 #include <linux/seqlock.h>
14 #include <linux/init.h>
15 #include <linux/slab.h>
16 #include <linux/nsproxy.h>
17 #include <linux/swap.h>
18 #include <net/snmp.h>
19 #include <net/icmp.h>
20 #include <net/ip.h>
21 #include <net/route.h>
22 #include <net/tcp.h>
23 #include <net/udp.h>
24 #include <net/cipso_ipv4.h>
25 #include <net/inet_frag.h>
26 #include <net/ping.h>
27 #include <net/protocol.h>
28 
29 static int zero;
30 static int one = 1;
31 static int four = 4;
32 static int thousand = 1000;
33 static int gso_max_segs = GSO_MAX_SEGS;
34 static int tcp_retr1_max = 255;
35 static int ip_local_port_range_min[] = { 1, 1 };
36 static int ip_local_port_range_max[] = { 65535, 65535 };
37 static int tcp_adv_win_scale_min = -31;
38 static int tcp_adv_win_scale_max = 31;
39 static int ip_privileged_port_min;
40 static int ip_privileged_port_max = 65535;
41 static int ip_ttl_min = 1;
42 static int ip_ttl_max = 255;
43 static int tcp_syn_retries_min = 1;
44 static int tcp_syn_retries_max = MAX_TCP_SYNCNT;
45 static int ip_ping_group_range_min[] = { 0, 0 };
46 static int ip_ping_group_range_max[] = { GID_T_MAX, GID_T_MAX };
47 
48 /* obsolete */
49 static int sysctl_tcp_low_latency __read_mostly;
50 
51 /* Update system visible IP port range */
52 static void set_local_port_range(struct net *net, int range[2])
53 {
54 	bool same_parity = !((range[0] ^ range[1]) & 1);
55 
56 	write_seqlock_bh(&net->ipv4.ip_local_ports.lock);
57 	if (same_parity && !net->ipv4.ip_local_ports.warned) {
58 		net->ipv4.ip_local_ports.warned = true;
59 		pr_err_ratelimited("ip_local_port_range: prefer different parity for start/end values.\n");
60 	}
61 	net->ipv4.ip_local_ports.range[0] = range[0];
62 	net->ipv4.ip_local_ports.range[1] = range[1];
63 	write_sequnlock_bh(&net->ipv4.ip_local_ports.lock);
64 }
65 
66 /* Validate changes from /proc interface. */
67 static int ipv4_local_port_range(struct ctl_table *table, int write,
68 				 void __user *buffer,
69 				 size_t *lenp, loff_t *ppos)
70 {
71 	struct net *net =
72 		container_of(table->data, struct net, ipv4.ip_local_ports.range);
73 	int ret;
74 	int range[2];
75 	struct ctl_table tmp = {
76 		.data = &range,
77 		.maxlen = sizeof(range),
78 		.mode = table->mode,
79 		.extra1 = &ip_local_port_range_min,
80 		.extra2 = &ip_local_port_range_max,
81 	};
82 
83 	inet_get_local_port_range(net, &range[0], &range[1]);
84 
85 	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
86 
87 	if (write && ret == 0) {
88 		/* Ensure that the upper limit is not smaller than the lower,
89 		 * and that the lower does not encroach upon the privileged
90 		 * port limit.
91 		 */
92 		if ((range[1] < range[0]) ||
93 		    (range[0] < net->ipv4.sysctl_ip_prot_sock))
94 			ret = -EINVAL;
95 		else
96 			set_local_port_range(net, range);
97 	}
98 
99 	return ret;
100 }
101 
102 /* Validate changes from /proc interface. */
103 static int ipv4_privileged_ports(struct ctl_table *table, int write,
104 				void __user *buffer, size_t *lenp, loff_t *ppos)
105 {
106 	struct net *net = container_of(table->data, struct net,
107 	    ipv4.sysctl_ip_prot_sock);
108 	int ret;
109 	int pports;
110 	int range[2];
111 	struct ctl_table tmp = {
112 		.data = &pports,
113 		.maxlen = sizeof(pports),
114 		.mode = table->mode,
115 		.extra1 = &ip_privileged_port_min,
116 		.extra2 = &ip_privileged_port_max,
117 	};
118 
119 	pports = net->ipv4.sysctl_ip_prot_sock;
120 
121 	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
122 
123 	if (write && ret == 0) {
124 		inet_get_local_port_range(net, &range[0], &range[1]);
125 		/* Ensure that the local port range doesn't overlap with the
126 		 * privileged port range.
127 		 */
128 		if (range[0] < pports)
129 			ret = -EINVAL;
130 		else
131 			net->ipv4.sysctl_ip_prot_sock = pports;
132 	}
133 
134 	return ret;
135 }
136 
137 static void inet_get_ping_group_range_table(struct ctl_table *table, kgid_t *low, kgid_t *high)
138 {
139 	kgid_t *data = table->data;
140 	struct net *net =
141 		container_of(table->data, struct net, ipv4.ping_group_range.range);
142 	unsigned int seq;
143 	do {
144 		seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
145 
146 		*low = data[0];
147 		*high = data[1];
148 	} while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
149 }
150 
151 /* Update system visible IP port range */
152 static void set_ping_group_range(struct ctl_table *table, kgid_t low, kgid_t high)
153 {
154 	kgid_t *data = table->data;
155 	struct net *net =
156 		container_of(table->data, struct net, ipv4.ping_group_range.range);
157 	write_seqlock(&net->ipv4.ping_group_range.lock);
158 	data[0] = low;
159 	data[1] = high;
160 	write_sequnlock(&net->ipv4.ping_group_range.lock);
161 }
162 
163 /* Validate changes from /proc interface. */
164 static int ipv4_ping_group_range(struct ctl_table *table, int write,
165 				 void __user *buffer,
166 				 size_t *lenp, loff_t *ppos)
167 {
168 	struct user_namespace *user_ns = current_user_ns();
169 	int ret;
170 	gid_t urange[2];
171 	kgid_t low, high;
172 	struct ctl_table tmp = {
173 		.data = &urange,
174 		.maxlen = sizeof(urange),
175 		.mode = table->mode,
176 		.extra1 = &ip_ping_group_range_min,
177 		.extra2 = &ip_ping_group_range_max,
178 	};
179 
180 	inet_get_ping_group_range_table(table, &low, &high);
181 	urange[0] = from_kgid_munged(user_ns, low);
182 	urange[1] = from_kgid_munged(user_ns, high);
183 	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
184 
185 	if (write && ret == 0) {
186 		low = make_kgid(user_ns, urange[0]);
187 		high = make_kgid(user_ns, urange[1]);
188 		if (!gid_valid(low) || !gid_valid(high) ||
189 		    (urange[1] < urange[0]) || gid_lt(high, low)) {
190 			low = make_kgid(&init_user_ns, 1);
191 			high = make_kgid(&init_user_ns, 0);
192 		}
193 		set_ping_group_range(table, low, high);
194 	}
195 
196 	return ret;
197 }
198 
199 static int proc_tcp_congestion_control(struct ctl_table *ctl, int write,
200 				       void __user *buffer, size_t *lenp, loff_t *ppos)
201 {
202 	char val[TCP_CA_NAME_MAX];
203 	struct ctl_table tbl = {
204 		.data = val,
205 		.maxlen = TCP_CA_NAME_MAX,
206 	};
207 	int ret;
208 
209 	tcp_get_default_congestion_control(val);
210 
211 	ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
212 	if (write && ret == 0)
213 		ret = tcp_set_default_congestion_control(val);
214 	return ret;
215 }
216 
217 static int proc_tcp_available_congestion_control(struct ctl_table *ctl,
218 						 int write,
219 						 void __user *buffer, size_t *lenp,
220 						 loff_t *ppos)
221 {
222 	struct ctl_table tbl = { .maxlen = TCP_CA_BUF_MAX, };
223 	int ret;
224 
225 	tbl.data = kmalloc(tbl.maxlen, GFP_USER);
226 	if (!tbl.data)
227 		return -ENOMEM;
228 	tcp_get_available_congestion_control(tbl.data, TCP_CA_BUF_MAX);
229 	ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
230 	kfree(tbl.data);
231 	return ret;
232 }
233 
234 static int proc_allowed_congestion_control(struct ctl_table *ctl,
235 					   int write,
236 					   void __user *buffer, size_t *lenp,
237 					   loff_t *ppos)
238 {
239 	struct ctl_table tbl = { .maxlen = TCP_CA_BUF_MAX };
240 	int ret;
241 
242 	tbl.data = kmalloc(tbl.maxlen, GFP_USER);
243 	if (!tbl.data)
244 		return -ENOMEM;
245 
246 	tcp_get_allowed_congestion_control(tbl.data, tbl.maxlen);
247 	ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
248 	if (write && ret == 0)
249 		ret = tcp_set_allowed_congestion_control(tbl.data);
250 	kfree(tbl.data);
251 	return ret;
252 }
253 
254 static int proc_tcp_fastopen_key(struct ctl_table *table, int write,
255 				 void __user *buffer, size_t *lenp,
256 				 loff_t *ppos)
257 {
258 	struct net *net = container_of(table->data, struct net,
259 	    ipv4.sysctl_tcp_fastopen);
260 	struct ctl_table tbl = { .maxlen = (TCP_FASTOPEN_KEY_LENGTH * 2 + 10) };
261 	struct tcp_fastopen_context *ctxt;
262 	int ret;
263 	u32  user_key[4]; /* 16 bytes, matching TCP_FASTOPEN_KEY_LENGTH */
264 
265 	tbl.data = kmalloc(tbl.maxlen, GFP_KERNEL);
266 	if (!tbl.data)
267 		return -ENOMEM;
268 
269 	rcu_read_lock();
270 	ctxt = rcu_dereference(net->ipv4.tcp_fastopen_ctx);
271 	if (ctxt)
272 		memcpy(user_key, ctxt->key, TCP_FASTOPEN_KEY_LENGTH);
273 	else
274 		memset(user_key, 0, sizeof(user_key));
275 	rcu_read_unlock();
276 
277 	snprintf(tbl.data, tbl.maxlen, "%08x-%08x-%08x-%08x",
278 		user_key[0], user_key[1], user_key[2], user_key[3]);
279 	ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
280 
281 	if (write && ret == 0) {
282 		if (sscanf(tbl.data, "%x-%x-%x-%x", user_key, user_key + 1,
283 			   user_key + 2, user_key + 3) != 4) {
284 			ret = -EINVAL;
285 			goto bad_key;
286 		}
287 		tcp_fastopen_reset_cipher(net, NULL, user_key,
288 					  TCP_FASTOPEN_KEY_LENGTH);
289 	}
290 
291 bad_key:
292 	pr_debug("proc FO key set 0x%x-%x-%x-%x <- 0x%s: %u\n",
293 	       user_key[0], user_key[1], user_key[2], user_key[3],
294 	       (char *)tbl.data, ret);
295 	kfree(tbl.data);
296 	return ret;
297 }
298 
299 static void proc_configure_early_demux(int enabled, int protocol)
300 {
301 	struct net_protocol *ipprot;
302 #if IS_ENABLED(CONFIG_IPV6)
303 	struct inet6_protocol *ip6prot;
304 #endif
305 
306 	rcu_read_lock();
307 
308 	ipprot = rcu_dereference(inet_protos[protocol]);
309 	if (ipprot)
310 		ipprot->early_demux = enabled ? ipprot->early_demux_handler :
311 						NULL;
312 
313 #if IS_ENABLED(CONFIG_IPV6)
314 	ip6prot = rcu_dereference(inet6_protos[protocol]);
315 	if (ip6prot)
316 		ip6prot->early_demux = enabled ? ip6prot->early_demux_handler :
317 						 NULL;
318 #endif
319 	rcu_read_unlock();
320 }
321 
322 static int proc_tcp_early_demux(struct ctl_table *table, int write,
323 				void __user *buffer, size_t *lenp, loff_t *ppos)
324 {
325 	int ret = 0;
326 
327 	ret = proc_dointvec(table, write, buffer, lenp, ppos);
328 
329 	if (write && !ret) {
330 		int enabled = init_net.ipv4.sysctl_tcp_early_demux;
331 
332 		proc_configure_early_demux(enabled, IPPROTO_TCP);
333 	}
334 
335 	return ret;
336 }
337 
338 static int proc_udp_early_demux(struct ctl_table *table, int write,
339 				void __user *buffer, size_t *lenp, loff_t *ppos)
340 {
341 	int ret = 0;
342 
343 	ret = proc_dointvec(table, write, buffer, lenp, ppos);
344 
345 	if (write && !ret) {
346 		int enabled = init_net.ipv4.sysctl_udp_early_demux;
347 
348 		proc_configure_early_demux(enabled, IPPROTO_UDP);
349 	}
350 
351 	return ret;
352 }
353 
354 static int proc_tfo_blackhole_detect_timeout(struct ctl_table *table,
355 					     int write,
356 					     void __user *buffer,
357 					     size_t *lenp, loff_t *ppos)
358 {
359 	struct net *net = container_of(table->data, struct net,
360 	    ipv4.sysctl_tcp_fastopen_blackhole_timeout);
361 	int ret;
362 
363 	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
364 	if (write && ret == 0)
365 		atomic_set(&net->ipv4.tfo_active_disable_times, 0);
366 
367 	return ret;
368 }
369 
370 static int proc_tcp_available_ulp(struct ctl_table *ctl,
371 				  int write,
372 				  void __user *buffer, size_t *lenp,
373 				  loff_t *ppos)
374 {
375 	struct ctl_table tbl = { .maxlen = TCP_ULP_BUF_MAX, };
376 	int ret;
377 
378 	tbl.data = kmalloc(tbl.maxlen, GFP_USER);
379 	if (!tbl.data)
380 		return -ENOMEM;
381 	tcp_get_available_ulp(tbl.data, TCP_ULP_BUF_MAX);
382 	ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
383 	kfree(tbl.data);
384 
385 	return ret;
386 }
387 
388 static struct ctl_table ipv4_table[] = {
389 	{
390 		.procname	= "tcp_max_orphans",
391 		.data		= &sysctl_tcp_max_orphans,
392 		.maxlen		= sizeof(int),
393 		.mode		= 0644,
394 		.proc_handler	= proc_dointvec
395 	},
396 	{
397 		.procname	= "inet_peer_threshold",
398 		.data		= &inet_peer_threshold,
399 		.maxlen		= sizeof(int),
400 		.mode		= 0644,
401 		.proc_handler	= proc_dointvec
402 	},
403 	{
404 		.procname	= "inet_peer_minttl",
405 		.data		= &inet_peer_minttl,
406 		.maxlen		= sizeof(int),
407 		.mode		= 0644,
408 		.proc_handler	= proc_dointvec_jiffies,
409 	},
410 	{
411 		.procname	= "inet_peer_maxttl",
412 		.data		= &inet_peer_maxttl,
413 		.maxlen		= sizeof(int),
414 		.mode		= 0644,
415 		.proc_handler	= proc_dointvec_jiffies,
416 	},
417 	{
418 		.procname	= "tcp_mem",
419 		.maxlen		= sizeof(sysctl_tcp_mem),
420 		.data		= &sysctl_tcp_mem,
421 		.mode		= 0644,
422 		.proc_handler	= proc_doulongvec_minmax,
423 	},
424 	{
425 		.procname	= "tcp_wmem",
426 		.data		= &sysctl_tcp_wmem,
427 		.maxlen		= sizeof(sysctl_tcp_wmem),
428 		.mode		= 0644,
429 		.proc_handler	= proc_dointvec_minmax,
430 		.extra1		= &one,
431 	},
432 	{
433 		.procname	= "tcp_rmem",
434 		.data		= &sysctl_tcp_rmem,
435 		.maxlen		= sizeof(sysctl_tcp_rmem),
436 		.mode		= 0644,
437 		.proc_handler	= proc_dointvec_minmax,
438 		.extra1		= &one,
439 	},
440 	{
441 		.procname	= "tcp_low_latency",
442 		.data		= &sysctl_tcp_low_latency,
443 		.maxlen		= sizeof(int),
444 		.mode		= 0644,
445 		.proc_handler	= proc_dointvec
446 	},
447 	{
448 		.procname	= "tcp_congestion_control",
449 		.mode		= 0644,
450 		.maxlen		= TCP_CA_NAME_MAX,
451 		.proc_handler	= proc_tcp_congestion_control,
452 	},
453 #ifdef CONFIG_NETLABEL
454 	{
455 		.procname	= "cipso_cache_enable",
456 		.data		= &cipso_v4_cache_enabled,
457 		.maxlen		= sizeof(int),
458 		.mode		= 0644,
459 		.proc_handler	= proc_dointvec,
460 	},
461 	{
462 		.procname	= "cipso_cache_bucket_size",
463 		.data		= &cipso_v4_cache_bucketsize,
464 		.maxlen		= sizeof(int),
465 		.mode		= 0644,
466 		.proc_handler	= proc_dointvec,
467 	},
468 	{
469 		.procname	= "cipso_rbm_optfmt",
470 		.data		= &cipso_v4_rbm_optfmt,
471 		.maxlen		= sizeof(int),
472 		.mode		= 0644,
473 		.proc_handler	= proc_dointvec,
474 	},
475 	{
476 		.procname	= "cipso_rbm_strictvalid",
477 		.data		= &cipso_v4_rbm_strictvalid,
478 		.maxlen		= sizeof(int),
479 		.mode		= 0644,
480 		.proc_handler	= proc_dointvec,
481 	},
482 #endif /* CONFIG_NETLABEL */
483 	{
484 		.procname	= "tcp_available_congestion_control",
485 		.maxlen		= TCP_CA_BUF_MAX,
486 		.mode		= 0444,
487 		.proc_handler   = proc_tcp_available_congestion_control,
488 	},
489 	{
490 		.procname	= "tcp_allowed_congestion_control",
491 		.maxlen		= TCP_CA_BUF_MAX,
492 		.mode		= 0644,
493 		.proc_handler   = proc_allowed_congestion_control,
494 	},
495 	{
496 		.procname	= "tcp_available_ulp",
497 		.maxlen		= TCP_ULP_BUF_MAX,
498 		.mode		= 0444,
499 		.proc_handler   = proc_tcp_available_ulp,
500 	},
501 	{
502 		.procname	= "icmp_msgs_per_sec",
503 		.data		= &sysctl_icmp_msgs_per_sec,
504 		.maxlen		= sizeof(int),
505 		.mode		= 0644,
506 		.proc_handler	= proc_dointvec_minmax,
507 		.extra1		= &zero,
508 	},
509 	{
510 		.procname	= "icmp_msgs_burst",
511 		.data		= &sysctl_icmp_msgs_burst,
512 		.maxlen		= sizeof(int),
513 		.mode		= 0644,
514 		.proc_handler	= proc_dointvec_minmax,
515 		.extra1		= &zero,
516 	},
517 	{
518 		.procname	= "udp_mem",
519 		.data		= &sysctl_udp_mem,
520 		.maxlen		= sizeof(sysctl_udp_mem),
521 		.mode		= 0644,
522 		.proc_handler	= proc_doulongvec_minmax,
523 	},
524 	{
525 		.procname	= "udp_rmem_min",
526 		.data		= &sysctl_udp_rmem_min,
527 		.maxlen		= sizeof(sysctl_udp_rmem_min),
528 		.mode		= 0644,
529 		.proc_handler	= proc_dointvec_minmax,
530 		.extra1		= &one
531 	},
532 	{
533 		.procname	= "udp_wmem_min",
534 		.data		= &sysctl_udp_wmem_min,
535 		.maxlen		= sizeof(sysctl_udp_wmem_min),
536 		.mode		= 0644,
537 		.proc_handler	= proc_dointvec_minmax,
538 		.extra1		= &one
539 	},
540 	{ }
541 };
542 
543 static struct ctl_table ipv4_net_table[] = {
544 	{
545 		.procname	= "icmp_echo_ignore_all",
546 		.data		= &init_net.ipv4.sysctl_icmp_echo_ignore_all,
547 		.maxlen		= sizeof(int),
548 		.mode		= 0644,
549 		.proc_handler	= proc_dointvec
550 	},
551 	{
552 		.procname	= "icmp_echo_ignore_broadcasts",
553 		.data		= &init_net.ipv4.sysctl_icmp_echo_ignore_broadcasts,
554 		.maxlen		= sizeof(int),
555 		.mode		= 0644,
556 		.proc_handler	= proc_dointvec
557 	},
558 	{
559 		.procname	= "icmp_ignore_bogus_error_responses",
560 		.data		= &init_net.ipv4.sysctl_icmp_ignore_bogus_error_responses,
561 		.maxlen		= sizeof(int),
562 		.mode		= 0644,
563 		.proc_handler	= proc_dointvec
564 	},
565 	{
566 		.procname	= "icmp_errors_use_inbound_ifaddr",
567 		.data		= &init_net.ipv4.sysctl_icmp_errors_use_inbound_ifaddr,
568 		.maxlen		= sizeof(int),
569 		.mode		= 0644,
570 		.proc_handler	= proc_dointvec
571 	},
572 	{
573 		.procname	= "icmp_ratelimit",
574 		.data		= &init_net.ipv4.sysctl_icmp_ratelimit,
575 		.maxlen		= sizeof(int),
576 		.mode		= 0644,
577 		.proc_handler	= proc_dointvec_ms_jiffies,
578 	},
579 	{
580 		.procname	= "icmp_ratemask",
581 		.data		= &init_net.ipv4.sysctl_icmp_ratemask,
582 		.maxlen		= sizeof(int),
583 		.mode		= 0644,
584 		.proc_handler	= proc_dointvec
585 	},
586 	{
587 		.procname	= "ping_group_range",
588 		.data		= &init_net.ipv4.ping_group_range.range,
589 		.maxlen		= sizeof(gid_t)*2,
590 		.mode		= 0644,
591 		.proc_handler	= ipv4_ping_group_range,
592 	},
593 	{
594 		.procname	= "tcp_ecn",
595 		.data		= &init_net.ipv4.sysctl_tcp_ecn,
596 		.maxlen		= sizeof(int),
597 		.mode		= 0644,
598 		.proc_handler	= proc_dointvec
599 	},
600 	{
601 		.procname	= "tcp_ecn_fallback",
602 		.data		= &init_net.ipv4.sysctl_tcp_ecn_fallback,
603 		.maxlen		= sizeof(int),
604 		.mode		= 0644,
605 		.proc_handler	= proc_dointvec
606 	},
607 	{
608 		.procname	= "ip_dynaddr",
609 		.data		= &init_net.ipv4.sysctl_ip_dynaddr,
610 		.maxlen		= sizeof(int),
611 		.mode		= 0644,
612 		.proc_handler	= proc_dointvec
613 	},
614 	{
615 		.procname	= "ip_early_demux",
616 		.data		= &init_net.ipv4.sysctl_ip_early_demux,
617 		.maxlen		= sizeof(int),
618 		.mode		= 0644,
619 		.proc_handler	= proc_dointvec
620 	},
621 	{
622 		.procname       = "udp_early_demux",
623 		.data           = &init_net.ipv4.sysctl_udp_early_demux,
624 		.maxlen         = sizeof(int),
625 		.mode           = 0644,
626 		.proc_handler   = proc_udp_early_demux
627 	},
628 	{
629 		.procname       = "tcp_early_demux",
630 		.data           = &init_net.ipv4.sysctl_tcp_early_demux,
631 		.maxlen         = sizeof(int),
632 		.mode           = 0644,
633 		.proc_handler   = proc_tcp_early_demux
634 	},
635 	{
636 		.procname	= "ip_default_ttl",
637 		.data		= &init_net.ipv4.sysctl_ip_default_ttl,
638 		.maxlen		= sizeof(int),
639 		.mode		= 0644,
640 		.proc_handler	= proc_dointvec_minmax,
641 		.extra1		= &ip_ttl_min,
642 		.extra2		= &ip_ttl_max,
643 	},
644 	{
645 		.procname	= "ip_local_port_range",
646 		.maxlen		= sizeof(init_net.ipv4.ip_local_ports.range),
647 		.data		= &init_net.ipv4.ip_local_ports.range,
648 		.mode		= 0644,
649 		.proc_handler	= ipv4_local_port_range,
650 	},
651 	{
652 		.procname	= "ip_local_reserved_ports",
653 		.data		= &init_net.ipv4.sysctl_local_reserved_ports,
654 		.maxlen		= 65536,
655 		.mode		= 0644,
656 		.proc_handler	= proc_do_large_bitmap,
657 	},
658 	{
659 		.procname	= "ip_no_pmtu_disc",
660 		.data		= &init_net.ipv4.sysctl_ip_no_pmtu_disc,
661 		.maxlen		= sizeof(int),
662 		.mode		= 0644,
663 		.proc_handler	= proc_dointvec
664 	},
665 	{
666 		.procname	= "ip_forward_use_pmtu",
667 		.data		= &init_net.ipv4.sysctl_ip_fwd_use_pmtu,
668 		.maxlen		= sizeof(int),
669 		.mode		= 0644,
670 		.proc_handler	= proc_dointvec,
671 	},
672 	{
673 		.procname	= "ip_nonlocal_bind",
674 		.data		= &init_net.ipv4.sysctl_ip_nonlocal_bind,
675 		.maxlen		= sizeof(int),
676 		.mode		= 0644,
677 		.proc_handler	= proc_dointvec
678 	},
679 	{
680 		.procname	= "fwmark_reflect",
681 		.data		= &init_net.ipv4.sysctl_fwmark_reflect,
682 		.maxlen		= sizeof(int),
683 		.mode		= 0644,
684 		.proc_handler	= proc_dointvec,
685 	},
686 	{
687 		.procname	= "tcp_fwmark_accept",
688 		.data		= &init_net.ipv4.sysctl_tcp_fwmark_accept,
689 		.maxlen		= sizeof(int),
690 		.mode		= 0644,
691 		.proc_handler	= proc_dointvec,
692 	},
693 #ifdef CONFIG_NET_L3_MASTER_DEV
694 	{
695 		.procname	= "tcp_l3mdev_accept",
696 		.data		= &init_net.ipv4.sysctl_tcp_l3mdev_accept,
697 		.maxlen		= sizeof(int),
698 		.mode		= 0644,
699 		.proc_handler	= proc_dointvec_minmax,
700 		.extra1		= &zero,
701 		.extra2		= &one,
702 	},
703 #endif
704 	{
705 		.procname	= "tcp_mtu_probing",
706 		.data		= &init_net.ipv4.sysctl_tcp_mtu_probing,
707 		.maxlen		= sizeof(int),
708 		.mode		= 0644,
709 		.proc_handler	= proc_dointvec,
710 	},
711 	{
712 		.procname	= "tcp_base_mss",
713 		.data		= &init_net.ipv4.sysctl_tcp_base_mss,
714 		.maxlen		= sizeof(int),
715 		.mode		= 0644,
716 		.proc_handler	= proc_dointvec,
717 	},
718 	{
719 		.procname	= "tcp_probe_threshold",
720 		.data		= &init_net.ipv4.sysctl_tcp_probe_threshold,
721 		.maxlen		= sizeof(int),
722 		.mode		= 0644,
723 		.proc_handler	= proc_dointvec,
724 	},
725 	{
726 		.procname	= "tcp_probe_interval",
727 		.data		= &init_net.ipv4.sysctl_tcp_probe_interval,
728 		.maxlen		= sizeof(int),
729 		.mode		= 0644,
730 		.proc_handler	= proc_dointvec,
731 	},
732 	{
733 		.procname	= "igmp_link_local_mcast_reports",
734 		.data		= &init_net.ipv4.sysctl_igmp_llm_reports,
735 		.maxlen		= sizeof(int),
736 		.mode		= 0644,
737 		.proc_handler	= proc_dointvec
738 	},
739 	{
740 		.procname	= "igmp_max_memberships",
741 		.data		= &init_net.ipv4.sysctl_igmp_max_memberships,
742 		.maxlen		= sizeof(int),
743 		.mode		= 0644,
744 		.proc_handler	= proc_dointvec
745 	},
746 	{
747 		.procname	= "igmp_max_msf",
748 		.data		= &init_net.ipv4.sysctl_igmp_max_msf,
749 		.maxlen		= sizeof(int),
750 		.mode		= 0644,
751 		.proc_handler	= proc_dointvec
752 	},
753 #ifdef CONFIG_IP_MULTICAST
754 	{
755 		.procname	= "igmp_qrv",
756 		.data		= &init_net.ipv4.sysctl_igmp_qrv,
757 		.maxlen		= sizeof(int),
758 		.mode		= 0644,
759 		.proc_handler	= proc_dointvec_minmax,
760 		.extra1		= &one
761 	},
762 #endif
763 	{
764 		.procname	= "tcp_keepalive_time",
765 		.data		= &init_net.ipv4.sysctl_tcp_keepalive_time,
766 		.maxlen		= sizeof(int),
767 		.mode		= 0644,
768 		.proc_handler	= proc_dointvec_jiffies,
769 	},
770 	{
771 		.procname	= "tcp_keepalive_probes",
772 		.data		= &init_net.ipv4.sysctl_tcp_keepalive_probes,
773 		.maxlen		= sizeof(int),
774 		.mode		= 0644,
775 		.proc_handler	= proc_dointvec
776 	},
777 	{
778 		.procname	= "tcp_keepalive_intvl",
779 		.data		= &init_net.ipv4.sysctl_tcp_keepalive_intvl,
780 		.maxlen		= sizeof(int),
781 		.mode		= 0644,
782 		.proc_handler	= proc_dointvec_jiffies,
783 	},
784 	{
785 		.procname	= "tcp_syn_retries",
786 		.data		= &init_net.ipv4.sysctl_tcp_syn_retries,
787 		.maxlen		= sizeof(int),
788 		.mode		= 0644,
789 		.proc_handler	= proc_dointvec_minmax,
790 		.extra1		= &tcp_syn_retries_min,
791 		.extra2		= &tcp_syn_retries_max
792 	},
793 	{
794 		.procname	= "tcp_synack_retries",
795 		.data		= &init_net.ipv4.sysctl_tcp_synack_retries,
796 		.maxlen		= sizeof(int),
797 		.mode		= 0644,
798 		.proc_handler	= proc_dointvec
799 	},
800 #ifdef CONFIG_SYN_COOKIES
801 	{
802 		.procname	= "tcp_syncookies",
803 		.data		= &init_net.ipv4.sysctl_tcp_syncookies,
804 		.maxlen		= sizeof(int),
805 		.mode		= 0644,
806 		.proc_handler	= proc_dointvec
807 	},
808 #endif
809 	{
810 		.procname	= "tcp_reordering",
811 		.data		= &init_net.ipv4.sysctl_tcp_reordering,
812 		.maxlen		= sizeof(int),
813 		.mode		= 0644,
814 		.proc_handler	= proc_dointvec
815 	},
816 	{
817 		.procname	= "tcp_retries1",
818 		.data		= &init_net.ipv4.sysctl_tcp_retries1,
819 		.maxlen		= sizeof(int),
820 		.mode		= 0644,
821 		.proc_handler	= proc_dointvec_minmax,
822 		.extra2		= &tcp_retr1_max
823 	},
824 	{
825 		.procname	= "tcp_retries2",
826 		.data		= &init_net.ipv4.sysctl_tcp_retries2,
827 		.maxlen		= sizeof(int),
828 		.mode		= 0644,
829 		.proc_handler	= proc_dointvec
830 	},
831 	{
832 		.procname	= "tcp_orphan_retries",
833 		.data		= &init_net.ipv4.sysctl_tcp_orphan_retries,
834 		.maxlen		= sizeof(int),
835 		.mode		= 0644,
836 		.proc_handler	= proc_dointvec
837 	},
838 	{
839 		.procname	= "tcp_fin_timeout",
840 		.data		= &init_net.ipv4.sysctl_tcp_fin_timeout,
841 		.maxlen		= sizeof(int),
842 		.mode		= 0644,
843 		.proc_handler	= proc_dointvec_jiffies,
844 	},
845 	{
846 		.procname	= "tcp_notsent_lowat",
847 		.data		= &init_net.ipv4.sysctl_tcp_notsent_lowat,
848 		.maxlen		= sizeof(unsigned int),
849 		.mode		= 0644,
850 		.proc_handler	= proc_douintvec,
851 	},
852 	{
853 		.procname	= "tcp_tw_reuse",
854 		.data		= &init_net.ipv4.sysctl_tcp_tw_reuse,
855 		.maxlen		= sizeof(int),
856 		.mode		= 0644,
857 		.proc_handler	= proc_dointvec
858 	},
859 	{
860 		.procname	= "tcp_max_tw_buckets",
861 		.data		= &init_net.ipv4.tcp_death_row.sysctl_max_tw_buckets,
862 		.maxlen		= sizeof(int),
863 		.mode		= 0644,
864 		.proc_handler	= proc_dointvec
865 	},
866 	{
867 		.procname	= "tcp_max_syn_backlog",
868 		.data		= &init_net.ipv4.sysctl_max_syn_backlog,
869 		.maxlen		= sizeof(int),
870 		.mode		= 0644,
871 		.proc_handler	= proc_dointvec
872 	},
873 	{
874 		.procname	= "tcp_fastopen",
875 		.data		= &init_net.ipv4.sysctl_tcp_fastopen,
876 		.maxlen		= sizeof(int),
877 		.mode		= 0644,
878 		.proc_handler	= proc_dointvec,
879 	},
880 	{
881 		.procname	= "tcp_fastopen_key",
882 		.mode		= 0600,
883 		.data		= &init_net.ipv4.sysctl_tcp_fastopen,
884 		.maxlen		= ((TCP_FASTOPEN_KEY_LENGTH * 2) + 10),
885 		.proc_handler	= proc_tcp_fastopen_key,
886 	},
887 	{
888 		.procname	= "tcp_fastopen_blackhole_timeout_sec",
889 		.data		= &init_net.ipv4.sysctl_tcp_fastopen_blackhole_timeout,
890 		.maxlen		= sizeof(int),
891 		.mode		= 0644,
892 		.proc_handler	= proc_tfo_blackhole_detect_timeout,
893 		.extra1		= &zero,
894 	},
895 #ifdef CONFIG_IP_ROUTE_MULTIPATH
896 	{
897 		.procname	= "fib_multipath_use_neigh",
898 		.data		= &init_net.ipv4.sysctl_fib_multipath_use_neigh,
899 		.maxlen		= sizeof(int),
900 		.mode		= 0644,
901 		.proc_handler	= proc_dointvec_minmax,
902 		.extra1		= &zero,
903 		.extra2		= &one,
904 	},
905 	{
906 		.procname	= "fib_multipath_hash_policy",
907 		.data		= &init_net.ipv4.sysctl_fib_multipath_hash_policy,
908 		.maxlen		= sizeof(int),
909 		.mode		= 0644,
910 		.proc_handler	= proc_dointvec_minmax,
911 		.extra1		= &zero,
912 		.extra2		= &one,
913 	},
914 #endif
915 	{
916 		.procname	= "ip_unprivileged_port_start",
917 		.maxlen		= sizeof(int),
918 		.data		= &init_net.ipv4.sysctl_ip_prot_sock,
919 		.mode		= 0644,
920 		.proc_handler	= ipv4_privileged_ports,
921 	},
922 #ifdef CONFIG_NET_L3_MASTER_DEV
923 	{
924 		.procname	= "udp_l3mdev_accept",
925 		.data		= &init_net.ipv4.sysctl_udp_l3mdev_accept,
926 		.maxlen		= sizeof(int),
927 		.mode		= 0644,
928 		.proc_handler	= proc_dointvec_minmax,
929 		.extra1		= &zero,
930 		.extra2		= &one,
931 	},
932 #endif
933 	{
934 		.procname	= "tcp_sack",
935 		.data		= &init_net.ipv4.sysctl_tcp_sack,
936 		.maxlen		= sizeof(int),
937 		.mode		= 0644,
938 		.proc_handler	= proc_dointvec
939 	},
940 	{
941 		.procname	= "tcp_window_scaling",
942 		.data		= &init_net.ipv4.sysctl_tcp_window_scaling,
943 		.maxlen		= sizeof(int),
944 		.mode		= 0644,
945 		.proc_handler	= proc_dointvec
946 	},
947 	{
948 		.procname	= "tcp_timestamps",
949 		.data		= &init_net.ipv4.sysctl_tcp_timestamps,
950 		.maxlen		= sizeof(int),
951 		.mode		= 0644,
952 		.proc_handler	= proc_dointvec
953 	},
954 	{
955 		.procname	= "tcp_early_retrans",
956 		.data		= &init_net.ipv4.sysctl_tcp_early_retrans,
957 		.maxlen		= sizeof(int),
958 		.mode		= 0644,
959 		.proc_handler	= proc_dointvec_minmax,
960 		.extra1		= &zero,
961 		.extra2		= &four,
962 	},
963 	{
964 		.procname	= "tcp_recovery",
965 		.data		= &init_net.ipv4.sysctl_tcp_recovery,
966 		.maxlen		= sizeof(int),
967 		.mode		= 0644,
968 		.proc_handler	= proc_dointvec,
969 	},
970 	{
971 		.procname       = "tcp_thin_linear_timeouts",
972 		.data           = &init_net.ipv4.sysctl_tcp_thin_linear_timeouts,
973 		.maxlen         = sizeof(int),
974 		.mode           = 0644,
975 		.proc_handler   = proc_dointvec
976 	},
977 	{
978 		.procname	= "tcp_slow_start_after_idle",
979 		.data		= &init_net.ipv4.sysctl_tcp_slow_start_after_idle,
980 		.maxlen		= sizeof(int),
981 		.mode		= 0644,
982 		.proc_handler	= proc_dointvec
983 	},
984 	{
985 		.procname	= "tcp_retrans_collapse",
986 		.data		= &init_net.ipv4.sysctl_tcp_retrans_collapse,
987 		.maxlen		= sizeof(int),
988 		.mode		= 0644,
989 		.proc_handler	= proc_dointvec
990 	},
991 	{
992 		.procname	= "tcp_stdurg",
993 		.data		= &init_net.ipv4.sysctl_tcp_stdurg,
994 		.maxlen		= sizeof(int),
995 		.mode		= 0644,
996 		.proc_handler	= proc_dointvec
997 	},
998 	{
999 		.procname	= "tcp_rfc1337",
1000 		.data		= &init_net.ipv4.sysctl_tcp_rfc1337,
1001 		.maxlen		= sizeof(int),
1002 		.mode		= 0644,
1003 		.proc_handler	= proc_dointvec
1004 	},
1005 	{
1006 		.procname	= "tcp_abort_on_overflow",
1007 		.data		= &init_net.ipv4.sysctl_tcp_abort_on_overflow,
1008 		.maxlen		= sizeof(int),
1009 		.mode		= 0644,
1010 		.proc_handler	= proc_dointvec
1011 	},
1012 	{
1013 		.procname	= "tcp_fack",
1014 		.data		= &init_net.ipv4.sysctl_tcp_fack,
1015 		.maxlen		= sizeof(int),
1016 		.mode		= 0644,
1017 		.proc_handler	= proc_dointvec
1018 	},
1019 	{
1020 		.procname	= "tcp_max_reordering",
1021 		.data		= &init_net.ipv4.sysctl_tcp_max_reordering,
1022 		.maxlen		= sizeof(int),
1023 		.mode		= 0644,
1024 		.proc_handler	= proc_dointvec
1025 	},
1026 	{
1027 		.procname	= "tcp_dsack",
1028 		.data		= &init_net.ipv4.sysctl_tcp_dsack,
1029 		.maxlen		= sizeof(int),
1030 		.mode		= 0644,
1031 		.proc_handler	= proc_dointvec
1032 	},
1033 	{
1034 		.procname	= "tcp_app_win",
1035 		.data		= &init_net.ipv4.sysctl_tcp_app_win,
1036 		.maxlen		= sizeof(int),
1037 		.mode		= 0644,
1038 		.proc_handler	= proc_dointvec
1039 	},
1040 	{
1041 		.procname	= "tcp_adv_win_scale",
1042 		.data		= &init_net.ipv4.sysctl_tcp_adv_win_scale,
1043 		.maxlen		= sizeof(int),
1044 		.mode		= 0644,
1045 		.proc_handler	= proc_dointvec_minmax,
1046 		.extra1		= &tcp_adv_win_scale_min,
1047 		.extra2		= &tcp_adv_win_scale_max,
1048 	},
1049 	{
1050 		.procname	= "tcp_frto",
1051 		.data		= &init_net.ipv4.sysctl_tcp_frto,
1052 		.maxlen		= sizeof(int),
1053 		.mode		= 0644,
1054 		.proc_handler	= proc_dointvec
1055 	},
1056 	{
1057 		.procname	= "tcp_no_metrics_save",
1058 		.data		= &init_net.ipv4.sysctl_tcp_nometrics_save,
1059 		.maxlen		= sizeof(int),
1060 		.mode		= 0644,
1061 		.proc_handler	= proc_dointvec,
1062 	},
1063 	{
1064 		.procname	= "tcp_moderate_rcvbuf",
1065 		.data		= &init_net.ipv4.sysctl_tcp_moderate_rcvbuf,
1066 		.maxlen		= sizeof(int),
1067 		.mode		= 0644,
1068 		.proc_handler	= proc_dointvec,
1069 	},
1070 	{
1071 		.procname	= "tcp_tso_win_divisor",
1072 		.data		= &init_net.ipv4.sysctl_tcp_tso_win_divisor,
1073 		.maxlen		= sizeof(int),
1074 		.mode		= 0644,
1075 		.proc_handler	= proc_dointvec,
1076 	},
1077 	{
1078 		.procname	= "tcp_workaround_signed_windows",
1079 		.data		= &init_net.ipv4.sysctl_tcp_workaround_signed_windows,
1080 		.maxlen		= sizeof(int),
1081 		.mode		= 0644,
1082 		.proc_handler	= proc_dointvec
1083 	},
1084 	{
1085 		.procname	= "tcp_limit_output_bytes",
1086 		.data		= &init_net.ipv4.sysctl_tcp_limit_output_bytes,
1087 		.maxlen		= sizeof(int),
1088 		.mode		= 0644,
1089 		.proc_handler	= proc_dointvec
1090 	},
1091 	{
1092 		.procname	= "tcp_challenge_ack_limit",
1093 		.data		= &init_net.ipv4.sysctl_tcp_challenge_ack_limit,
1094 		.maxlen		= sizeof(int),
1095 		.mode		= 0644,
1096 		.proc_handler	= proc_dointvec
1097 	},
1098 	{
1099 		.procname	= "tcp_min_tso_segs",
1100 		.data		= &init_net.ipv4.sysctl_tcp_min_tso_segs,
1101 		.maxlen		= sizeof(int),
1102 		.mode		= 0644,
1103 		.proc_handler	= proc_dointvec_minmax,
1104 		.extra1		= &one,
1105 		.extra2		= &gso_max_segs,
1106 	},
1107 	{
1108 		.procname	= "tcp_min_rtt_wlen",
1109 		.data		= &init_net.ipv4.sysctl_tcp_min_rtt_wlen,
1110 		.maxlen		= sizeof(int),
1111 		.mode		= 0644,
1112 		.proc_handler	= proc_dointvec
1113 	},
1114 	{
1115 		.procname	= "tcp_autocorking",
1116 		.data		= &init_net.ipv4.sysctl_tcp_autocorking,
1117 		.maxlen		= sizeof(int),
1118 		.mode		= 0644,
1119 		.proc_handler	= proc_dointvec_minmax,
1120 		.extra1		= &zero,
1121 		.extra2		= &one,
1122 	},
1123 	{
1124 		.procname	= "tcp_invalid_ratelimit",
1125 		.data		= &init_net.ipv4.sysctl_tcp_invalid_ratelimit,
1126 		.maxlen		= sizeof(int),
1127 		.mode		= 0644,
1128 		.proc_handler	= proc_dointvec_ms_jiffies,
1129 	},
1130 	{
1131 		.procname	= "tcp_pacing_ss_ratio",
1132 		.data		= &init_net.ipv4.sysctl_tcp_pacing_ss_ratio,
1133 		.maxlen		= sizeof(int),
1134 		.mode		= 0644,
1135 		.proc_handler	= proc_dointvec_minmax,
1136 		.extra1		= &zero,
1137 		.extra2		= &thousand,
1138 	},
1139 	{
1140 		.procname	= "tcp_pacing_ca_ratio",
1141 		.data		= &init_net.ipv4.sysctl_tcp_pacing_ca_ratio,
1142 		.maxlen		= sizeof(int),
1143 		.mode		= 0644,
1144 		.proc_handler	= proc_dointvec_minmax,
1145 		.extra1		= &zero,
1146 		.extra2		= &thousand,
1147 	},
1148 	{ }
1149 };
1150 
1151 static __net_init int ipv4_sysctl_init_net(struct net *net)
1152 {
1153 	struct ctl_table *table;
1154 
1155 	table = ipv4_net_table;
1156 	if (!net_eq(net, &init_net)) {
1157 		int i;
1158 
1159 		table = kmemdup(table, sizeof(ipv4_net_table), GFP_KERNEL);
1160 		if (!table)
1161 			goto err_alloc;
1162 
1163 		/* Update the variables to point into the current struct net */
1164 		for (i = 0; i < ARRAY_SIZE(ipv4_net_table) - 1; i++)
1165 			table[i].data += (void *)net - (void *)&init_net;
1166 	}
1167 
1168 	net->ipv4.ipv4_hdr = register_net_sysctl(net, "net/ipv4", table);
1169 	if (!net->ipv4.ipv4_hdr)
1170 		goto err_reg;
1171 
1172 	net->ipv4.sysctl_local_reserved_ports = kzalloc(65536 / 8, GFP_KERNEL);
1173 	if (!net->ipv4.sysctl_local_reserved_ports)
1174 		goto err_ports;
1175 
1176 	return 0;
1177 
1178 err_ports:
1179 	unregister_net_sysctl_table(net->ipv4.ipv4_hdr);
1180 err_reg:
1181 	if (!net_eq(net, &init_net))
1182 		kfree(table);
1183 err_alloc:
1184 	return -ENOMEM;
1185 }
1186 
1187 static __net_exit void ipv4_sysctl_exit_net(struct net *net)
1188 {
1189 	struct ctl_table *table;
1190 
1191 	kfree(net->ipv4.sysctl_local_reserved_ports);
1192 	table = net->ipv4.ipv4_hdr->ctl_table_arg;
1193 	unregister_net_sysctl_table(net->ipv4.ipv4_hdr);
1194 	kfree(table);
1195 }
1196 
1197 static __net_initdata struct pernet_operations ipv4_sysctl_ops = {
1198 	.init = ipv4_sysctl_init_net,
1199 	.exit = ipv4_sysctl_exit_net,
1200 };
1201 
1202 static __init int sysctl_ipv4_init(void)
1203 {
1204 	struct ctl_table_header *hdr;
1205 
1206 	hdr = register_net_sysctl(&init_net, "net/ipv4", ipv4_table);
1207 	if (!hdr)
1208 		return -ENOMEM;
1209 
1210 	if (register_pernet_subsys(&ipv4_sysctl_ops)) {
1211 		unregister_net_sysctl_table(hdr);
1212 		return -ENOMEM;
1213 	}
1214 
1215 	return 0;
1216 }
1217 
1218 __initcall(sysctl_ipv4_init);
1219