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Linux/net/core/sysctl_net_core.c

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  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/mm.h>
 10 #include <linux/sysctl.h>
 11 #include <linux/module.h>
 12 #include <linux/socket.h>
 13 #include <linux/netdevice.h>
 14 #include <linux/ratelimit.h>
 15 #include <linux/vmalloc.h>
 16 #include <linux/init.h>
 17 #include <linux/slab.h>
 18 
 19 #include <net/ip.h>
 20 #include <net/sock.h>
 21 #include <net/net_ratelimit.h>
 22 #include <net/busy_poll.h>
 23 #include <net/pkt_sched.h>
 24 
 25 static int two __maybe_unused = 2;
 26 static int min_sndbuf = SOCK_MIN_SNDBUF;
 27 static int min_rcvbuf = SOCK_MIN_RCVBUF;
 28 static int max_skb_frags = MAX_SKB_FRAGS;
 29 static long long_one __maybe_unused = 1;
 30 static long long_max __maybe_unused = LONG_MAX;
 31 
 32 static int net_msg_warn;        /* Unused, but still a sysctl */
 33 
 34 int sysctl_fb_tunnels_only_for_init_net __read_mostly = 0;
 35 EXPORT_SYMBOL(sysctl_fb_tunnels_only_for_init_net);
 36 
 37 /* 0 - Keep current behavior:
 38  *     IPv4: inherit all current settings from init_net
 39  *     IPv6: reset all settings to default
 40  * 1 - Both inherit all current settings from init_net
 41  * 2 - Both reset all settings to default
 42  */
 43 int sysctl_devconf_inherit_init_net __read_mostly;
 44 EXPORT_SYMBOL(sysctl_devconf_inherit_init_net);
 45 
 46 #ifdef CONFIG_RPS
 47 static int rps_sock_flow_sysctl(struct ctl_table *table, int write,
 48                                 void __user *buffer, size_t *lenp, loff_t *ppos)
 49 {
 50         unsigned int orig_size, size;
 51         int ret, i;
 52         struct ctl_table tmp = {
 53                 .data = &size,
 54                 .maxlen = sizeof(size),
 55                 .mode = table->mode
 56         };
 57         struct rps_sock_flow_table *orig_sock_table, *sock_table;
 58         static DEFINE_MUTEX(sock_flow_mutex);
 59 
 60         mutex_lock(&sock_flow_mutex);
 61 
 62         orig_sock_table = rcu_dereference_protected(rps_sock_flow_table,
 63                                         lockdep_is_held(&sock_flow_mutex));
 64         size = orig_size = orig_sock_table ? orig_sock_table->mask + 1 : 0;
 65 
 66         ret = proc_dointvec(&tmp, write, buffer, lenp, ppos);
 67 
 68         if (write) {
 69                 if (size) {
 70                         if (size > 1<<29) {
 71                                 /* Enforce limit to prevent overflow */
 72                                 mutex_unlock(&sock_flow_mutex);
 73                                 return -EINVAL;
 74                         }
 75                         size = roundup_pow_of_two(size);
 76                         if (size != orig_size) {
 77                                 sock_table =
 78                                     vmalloc(RPS_SOCK_FLOW_TABLE_SIZE(size));
 79                                 if (!sock_table) {
 80                                         mutex_unlock(&sock_flow_mutex);
 81                                         return -ENOMEM;
 82                                 }
 83                                 rps_cpu_mask = roundup_pow_of_two(nr_cpu_ids) - 1;
 84                                 sock_table->mask = size - 1;
 85                         } else
 86                                 sock_table = orig_sock_table;
 87 
 88                         for (i = 0; i < size; i++)
 89                                 sock_table->ents[i] = RPS_NO_CPU;
 90                 } else
 91                         sock_table = NULL;
 92 
 93                 if (sock_table != orig_sock_table) {
 94                         rcu_assign_pointer(rps_sock_flow_table, sock_table);
 95                         if (sock_table) {
 96                                 static_branch_inc(&rps_needed);
 97                                 static_branch_inc(&rfs_needed);
 98                         }
 99                         if (orig_sock_table) {
100                                 static_branch_dec(&rps_needed);
101                                 static_branch_dec(&rfs_needed);
102                                 synchronize_rcu();
103                                 vfree(orig_sock_table);
104                         }
105                 }
106         }
107 
108         mutex_unlock(&sock_flow_mutex);
109 
110         return ret;
111 }
112 #endif /* CONFIG_RPS */
113 
114 #ifdef CONFIG_NET_FLOW_LIMIT
115 static DEFINE_MUTEX(flow_limit_update_mutex);
116 
117 static int flow_limit_cpu_sysctl(struct ctl_table *table, int write,
118                                  void __user *buffer, size_t *lenp,
119                                  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_user(buffer, *lenp, 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                                 synchronize_rcu();
143                                 kfree(cur);
144                         } else if (!cur && cpumask_test_cpu(i, mask)) {
145                                 cur = kzalloc_node(len, GFP_KERNEL,
146                                                    cpu_to_node(i));
147                                 if (!cur) {
148                                         /* not unwinding previous changes */
149                                         ret = -ENOMEM;
150                                         goto write_unlock;
151                                 }
152                                 cur->num_buckets = netdev_flow_limit_table_len;
153                                 rcu_assign_pointer(sd->flow_limit, cur);
154                         }
155                 }
156 write_unlock:
157                 mutex_unlock(&flow_limit_update_mutex);
158         } else {
159                 char kbuf[128];
160 
161                 if (*ppos || !*lenp) {
162                         *lenp = 0;
163                         goto done;
164                 }
165 
166                 cpumask_clear(mask);
167                 rcu_read_lock();
168                 for_each_possible_cpu(i) {
169                         sd = &per_cpu(softnet_data, i);
170                         if (rcu_dereference(sd->flow_limit))
171                                 cpumask_set_cpu(i, mask);
172                 }
173                 rcu_read_unlock();
174 
175                 len = min(sizeof(kbuf) - 1, *lenp);
176                 len = scnprintf(kbuf, len, "%*pb", cpumask_pr_args(mask));
177                 if (!len) {
178                         *lenp = 0;
179                         goto done;
180                 }
181                 if (len < *lenp)
182                         kbuf[len++] = '\n';
183                 if (copy_to_user(buffer, kbuf, len)) {
184                         ret = -EFAULT;
185                         goto done;
186                 }
187                 *lenp = len;
188                 *ppos += len;
189         }
190 
191 done:
192         free_cpumask_var(mask);
193         return ret;
194 }
195 
196 static int flow_limit_table_len_sysctl(struct ctl_table *table, int write,
197                                        void __user *buffer, size_t *lenp,
198                                        loff_t *ppos)
199 {
200         unsigned int old, *ptr;
201         int ret;
202 
203         mutex_lock(&flow_limit_update_mutex);
204 
205         ptr = table->data;
206         old = *ptr;
207         ret = proc_dointvec(table, write, buffer, lenp, ppos);
208         if (!ret && write && !is_power_of_2(*ptr)) {
209                 *ptr = old;
210                 ret = -EINVAL;
211         }
212 
213         mutex_unlock(&flow_limit_update_mutex);
214         return ret;
215 }
216 #endif /* CONFIG_NET_FLOW_LIMIT */
217 
218 #ifdef CONFIG_NET_SCHED
219 static int set_default_qdisc(struct ctl_table *table, int write,
220                              void __user *buffer, size_t *lenp, loff_t *ppos)
221 {
222         char id[IFNAMSIZ];
223         struct ctl_table tbl = {
224                 .data = id,
225                 .maxlen = IFNAMSIZ,
226         };
227         int ret;
228 
229         qdisc_get_default(id, IFNAMSIZ);
230 
231         ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
232         if (write && ret == 0)
233                 ret = qdisc_set_default(id);
234         return ret;
235 }
236 #endif
237 
238 static int proc_do_dev_weight(struct ctl_table *table, int write,
239                            void __user *buffer, size_t *lenp, loff_t *ppos)
240 {
241         int ret;
242 
243         ret = proc_dointvec(table, write, buffer, lenp, ppos);
244         if (ret != 0)
245                 return ret;
246 
247         dev_rx_weight = weight_p * dev_weight_rx_bias;
248         dev_tx_weight = weight_p * dev_weight_tx_bias;
249 
250         return ret;
251 }
252 
253 static int proc_do_rss_key(struct ctl_table *table, int write,
254                            void __user *buffer, size_t *lenp, loff_t *ppos)
255 {
256         struct ctl_table fake_table;
257         char buf[NETDEV_RSS_KEY_LEN * 3];
258 
259         snprintf(buf, sizeof(buf), "%*phC", NETDEV_RSS_KEY_LEN, netdev_rss_key);
260         fake_table.data = buf;
261         fake_table.maxlen = sizeof(buf);
262         return proc_dostring(&fake_table, write, buffer, lenp, ppos);
263 }
264 
265 #ifdef CONFIG_BPF_JIT
266 static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write,
267                                            void __user *buffer, size_t *lenp,
268                                            loff_t *ppos)
269 {
270         int ret, jit_enable = *(int *)table->data;
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())) {
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         return ret;
289 }
290 
291 # ifdef CONFIG_HAVE_EBPF_JIT
292 static int
293 proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
294                                     void __user *buffer, size_t *lenp,
295                                     loff_t *ppos)
296 {
297         if (!capable(CAP_SYS_ADMIN))
298                 return -EPERM;
299 
300         return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
301 }
302 # endif /* CONFIG_HAVE_EBPF_JIT */
303 
304 static int
305 proc_dolongvec_minmax_bpf_restricted(struct ctl_table *table, int write,
306                                      void __user *buffer, size_t *lenp,
307                                      loff_t *ppos)
308 {
309         if (!capable(CAP_SYS_ADMIN))
310                 return -EPERM;
311 
312         return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
313 }
314 #endif
315 
316 static struct ctl_table net_core_table[] = {
317 #ifdef CONFIG_NET
318         {
319                 .procname       = "wmem_max",
320                 .data           = &sysctl_wmem_max,
321                 .maxlen         = sizeof(int),
322                 .mode           = 0644,
323                 .proc_handler   = proc_dointvec_minmax,
324                 .extra1         = &min_sndbuf,
325         },
326         {
327                 .procname       = "rmem_max",
328                 .data           = &sysctl_rmem_max,
329                 .maxlen         = sizeof(int),
330                 .mode           = 0644,
331                 .proc_handler   = proc_dointvec_minmax,
332                 .extra1         = &min_rcvbuf,
333         },
334         {
335                 .procname       = "wmem_default",
336                 .data           = &sysctl_wmem_default,
337                 .maxlen         = sizeof(int),
338                 .mode           = 0644,
339                 .proc_handler   = proc_dointvec_minmax,
340                 .extra1         = &min_sndbuf,
341         },
342         {
343                 .procname       = "rmem_default",
344                 .data           = &sysctl_rmem_default,
345                 .maxlen         = sizeof(int),
346                 .mode           = 0644,
347                 .proc_handler   = proc_dointvec_minmax,
348                 .extra1         = &min_rcvbuf,
349         },
350         {
351                 .procname       = "dev_weight",
352                 .data           = &weight_p,
353                 .maxlen         = sizeof(int),
354                 .mode           = 0644,
355                 .proc_handler   = proc_do_dev_weight,
356         },
357         {
358                 .procname       = "dev_weight_rx_bias",
359                 .data           = &dev_weight_rx_bias,
360                 .maxlen         = sizeof(int),
361                 .mode           = 0644,
362                 .proc_handler   = proc_do_dev_weight,
363         },
364         {
365                 .procname       = "dev_weight_tx_bias",
366                 .data           = &dev_weight_tx_bias,
367                 .maxlen         = sizeof(int),
368                 .mode           = 0644,
369                 .proc_handler   = proc_do_dev_weight,
370         },
371         {
372                 .procname       = "netdev_max_backlog",
373                 .data           = &netdev_max_backlog,
374                 .maxlen         = sizeof(int),
375                 .mode           = 0644,
376                 .proc_handler   = proc_dointvec
377         },
378         {
379                 .procname       = "netdev_rss_key",
380                 .data           = &netdev_rss_key,
381                 .maxlen         = sizeof(int),
382                 .mode           = 0444,
383                 .proc_handler   = proc_do_rss_key,
384         },
385 #ifdef CONFIG_BPF_JIT
386         {
387                 .procname       = "bpf_jit_enable",
388                 .data           = &bpf_jit_enable,
389                 .maxlen         = sizeof(int),
390                 .mode           = 0644,
391                 .proc_handler   = proc_dointvec_minmax_bpf_enable,
392 # ifdef CONFIG_BPF_JIT_ALWAYS_ON
393                 .extra1         = SYSCTL_ONE,
394                 .extra2         = SYSCTL_ONE,
395 # else
396                 .extra1         = SYSCTL_ZERO,
397                 .extra2         = &two,
398 # endif
399         },
400 # ifdef CONFIG_HAVE_EBPF_JIT
401         {
402                 .procname       = "bpf_jit_harden",
403                 .data           = &bpf_jit_harden,
404                 .maxlen         = sizeof(int),
405                 .mode           = 0600,
406                 .proc_handler   = proc_dointvec_minmax_bpf_restricted,
407                 .extra1         = SYSCTL_ZERO,
408                 .extra2         = &two,
409         },
410         {
411                 .procname       = "bpf_jit_kallsyms",
412                 .data           = &bpf_jit_kallsyms,
413                 .maxlen         = sizeof(int),
414                 .mode           = 0600,
415                 .proc_handler   = proc_dointvec_minmax_bpf_restricted,
416                 .extra1         = SYSCTL_ZERO,
417                 .extra2         = SYSCTL_ONE,
418         },
419 # endif
420         {
421                 .procname       = "bpf_jit_limit",
422                 .data           = &bpf_jit_limit,
423                 .maxlen         = sizeof(long),
424                 .mode           = 0600,
425                 .proc_handler   = proc_dolongvec_minmax_bpf_restricted,
426                 .extra1         = &long_one,
427                 .extra2         = &long_max,
428         },
429 #endif
430         {
431                 .procname       = "netdev_tstamp_prequeue",
432                 .data           = &netdev_tstamp_prequeue,
433                 .maxlen         = sizeof(int),
434                 .mode           = 0644,
435                 .proc_handler   = proc_dointvec
436         },
437         {
438                 .procname       = "message_cost",
439                 .data           = &net_ratelimit_state.interval,
440                 .maxlen         = sizeof(int),
441                 .mode           = 0644,
442                 .proc_handler   = proc_dointvec_jiffies,
443         },
444         {
445                 .procname       = "message_burst",
446                 .data           = &net_ratelimit_state.burst,
447                 .maxlen         = sizeof(int),
448                 .mode           = 0644,
449                 .proc_handler   = proc_dointvec,
450         },
451         {
452                 .procname       = "optmem_max",
453                 .data           = &sysctl_optmem_max,
454                 .maxlen         = sizeof(int),
455                 .mode           = 0644,
456                 .proc_handler   = proc_dointvec
457         },
458         {
459                 .procname       = "tstamp_allow_data",
460                 .data           = &sysctl_tstamp_allow_data,
461                 .maxlen         = sizeof(int),
462                 .mode           = 0644,
463                 .proc_handler   = proc_dointvec_minmax,
464                 .extra1         = SYSCTL_ZERO,
465                 .extra2         = SYSCTL_ONE
466         },
467 #ifdef CONFIG_RPS
468         {
469                 .procname       = "rps_sock_flow_entries",
470                 .maxlen         = sizeof(int),
471                 .mode           = 0644,
472                 .proc_handler   = rps_sock_flow_sysctl
473         },
474 #endif
475 #ifdef CONFIG_NET_FLOW_LIMIT
476         {
477                 .procname       = "flow_limit_cpu_bitmap",
478                 .mode           = 0644,
479                 .proc_handler   = flow_limit_cpu_sysctl
480         },
481         {
482                 .procname       = "flow_limit_table_len",
483                 .data           = &netdev_flow_limit_table_len,
484                 .maxlen         = sizeof(int),
485                 .mode           = 0644,
486                 .proc_handler   = flow_limit_table_len_sysctl
487         },
488 #endif /* CONFIG_NET_FLOW_LIMIT */
489 #ifdef CONFIG_NET_RX_BUSY_POLL
490         {
491                 .procname       = "busy_poll",
492                 .data           = &sysctl_net_busy_poll,
493                 .maxlen         = sizeof(unsigned int),
494                 .mode           = 0644,
495                 .proc_handler   = proc_dointvec_minmax,
496                 .extra1         = SYSCTL_ZERO,
497         },
498         {
499                 .procname       = "busy_read",
500                 .data           = &sysctl_net_busy_read,
501                 .maxlen         = sizeof(unsigned int),
502                 .mode           = 0644,
503                 .proc_handler   = proc_dointvec_minmax,
504                 .extra1         = SYSCTL_ZERO,
505         },
506 #endif
507 #ifdef CONFIG_NET_SCHED
508         {
509                 .procname       = "default_qdisc",
510                 .mode           = 0644,
511                 .maxlen         = IFNAMSIZ,
512                 .proc_handler   = set_default_qdisc
513         },
514 #endif
515 #endif /* CONFIG_NET */
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_ONE,
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         = &two,
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 };
582 
583 static struct ctl_table netns_core_table[] = {
584         {
585                 .procname       = "somaxconn",
586                 .data           = &init_net.core.sysctl_somaxconn,
587                 .maxlen         = sizeof(int),
588                 .mode           = 0644,
589                 .extra1         = SYSCTL_ZERO,
590                 .proc_handler   = proc_dointvec_minmax
591         },
592         { }
593 };
594 
595 static __net_init int sysctl_core_net_init(struct net *net)
596 {
597         struct ctl_table *tbl;
598 
599         tbl = netns_core_table;
600         if (!net_eq(net, &init_net)) {
601                 tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);
602                 if (tbl == NULL)
603                         goto err_dup;
604 
605                 tbl[0].data = &net->core.sysctl_somaxconn;
606 
607                 /* Don't export any sysctls to unprivileged users */
608                 if (net->user_ns != &init_user_ns) {
609                         tbl[0].procname = NULL;
610                 }
611         }
612 
613         net->core.sysctl_hdr = register_net_sysctl(net, "net/core", tbl);
614         if (net->core.sysctl_hdr == NULL)
615                 goto err_reg;
616 
617         return 0;
618 
619 err_reg:
620         if (tbl != netns_core_table)
621                 kfree(tbl);
622 err_dup:
623         return -ENOMEM;
624 }
625 
626 static __net_exit void sysctl_core_net_exit(struct net *net)
627 {
628         struct ctl_table *tbl;
629 
630         tbl = net->core.sysctl_hdr->ctl_table_arg;
631         unregister_net_sysctl_table(net->core.sysctl_hdr);
632         BUG_ON(tbl == netns_core_table);
633         kfree(tbl);
634 }
635 
636 static __net_initdata struct pernet_operations sysctl_core_ops = {
637         .init = sysctl_core_net_init,
638         .exit = sysctl_core_net_exit,
639 };
640 
641 static __init int sysctl_core_init(void)
642 {
643         register_net_sysctl(&init_net, "net/core", net_core_table);
644         return register_pernet_subsys(&sysctl_core_ops);
645 }
646 
647 fs_initcall(sysctl_core_init);
648 

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