net/core/sysctl_net_core.c

   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 = 2;
  26 static int three = 3;
  27 static int min_sndbuf = SOCK_MIN_SNDBUF;
  28 static int min_rcvbuf = SOCK_MIN_RCVBUF;
  29 static int max_skb_frags = MAX_SKB_FRAGS;
  30 static long long_one __maybe_unused = 1;
  31 static long long_max __maybe_unused = LONG_MAX;
  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                                 synchronize_rcu();
 105                                 vfree(orig_sock_table);
 106                         }
 107                 }
 108         }
 109
 110         mutex_unlock(&sock_flow_mutex);
 111
 112         return ret;
 113 }
 114 #endif /* CONFIG_RPS */
 115
 116 #ifdef CONFIG_NET_FLOW_LIMIT
 117 static DEFINE_MUTEX(flow_limit_update_mutex);
 118
 119 static int flow_limit_cpu_sysctl(struct ctl_table *table, int write,
 120                                  void *buffer, size_t *lenp, loff_t *ppos)
 121 {
 122         struct sd_flow_limit *cur;
 123         struct softnet_data *sd;
 124         cpumask_var_t mask;
 125         int i, len, ret = 0;
 126
 127         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
 128                 return -ENOMEM;
 129
 130         if (write) {
 131                 ret = cpumask_parse(buffer, mask);
 132                 if (ret)
 133                         goto done;
 134
 135                 mutex_lock(&flow_limit_update_mutex);
 136                 len = sizeof(*cur) + netdev_flow_limit_table_len;
 137                 for_each_possible_cpu(i) {
 138                         sd = &per_cpu(softnet_data, i);
 139                         cur = rcu_dereference_protected(sd->flow_limit,
 140                                      lockdep_is_held(&flow_limit_update_mutex));
 141                         if (cur && !cpumask_test_cpu(i, mask)) {
 142                                 RCU_INIT_POINTER(sd->flow_limit, NULL);
 143                                 synchronize_rcu();
 144                                 kfree(cur);
 145                         } else if (!cur && cpumask_test_cpu(i, mask)) {
 146                                 cur = kzalloc_node(len, GFP_KERNEL,
 147                                                    cpu_to_node(i));
 148                                 if (!cur) {
 149                                         /* not unwinding previous changes */
 150                                         ret = -ENOMEM;
 151                                         goto write_unlock;
 152                                 }
 153                                 cur->num_buckets = netdev_flow_limit_table_len;
 154                                 rcu_assign_pointer(sd->flow_limit, cur);
 155                         }
 156                 }
 157 write_unlock:
 158                 mutex_unlock(&flow_limit_update_mutex);
 159         } else {
 160                 char kbuf[128];
 161
 162                 if (*ppos || !*lenp) {
 163                         *lenp = 0;
 164                         goto done;
 165                 }
 166
 167                 cpumask_clear(mask);
 168                 rcu_read_lock();
 169                 for_each_possible_cpu(i) {
 170                         sd = &per_cpu(softnet_data, i);
 171                         if (rcu_dereference(sd->flow_limit))
 172                                 cpumask_set_cpu(i, mask);
 173                 }
 174                 rcu_read_unlock();
 175
 176                 len = min(sizeof(kbuf) - 1, *lenp);
 177                 len = scnprintf(kbuf, len, "%*pb", cpumask_pr_args(mask));
 178                 if (!len) {
 179                         *lenp = 0;
 180                         goto done;
 181                 }
 182                 if (len < *lenp)
 183                         kbuf[len++] = '\n';
 184                 memcpy(buffer, kbuf, len);
 185                 *lenp = len;
 186                 *ppos += len;
 187         }
 188
 189 done:
 190         free_cpumask_var(mask);
 191         return ret;
 192 }
 193
 194 static int flow_limit_table_len_sysctl(struct ctl_table *table, int write,
 195                                        void *buffer, size_t *lenp, loff_t *ppos)
 196 {
 197         unsigned int old, *ptr;
 198         int ret;
 199
 200         mutex_lock(&flow_limit_update_mutex);
 201
 202         ptr = table->data;
 203         old = *ptr;
 204         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 205         if (!ret && write && !is_power_of_2(*ptr)) {
 206                 *ptr = old;
 207                 ret = -EINVAL;
 208         }
 209
 210         mutex_unlock(&flow_limit_update_mutex);
 211         return ret;
 212 }
 213 #endif /* CONFIG_NET_FLOW_LIMIT */
 214
 215 #ifdef CONFIG_NET_SCHED
 216 static int set_default_qdisc(struct ctl_table *table, int write,
 217                              void *buffer, size_t *lenp, loff_t *ppos)
 218 {
 219         char id[IFNAMSIZ];
 220         struct ctl_table tbl = {
 221                 .data = id,
 222                 .maxlen = IFNAMSIZ,
 223         };
 224         int ret;
 225
 226         qdisc_get_default(id, IFNAMSIZ);
 227
 228         ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
 229         if (write && ret == 0)
 230                 ret = qdisc_set_default(id);
 231         return ret;
 232 }
 233 #endif
 234
 235 static int proc_do_dev_weight(struct ctl_table *table, int write,
 236                            void *buffer, size_t *lenp, loff_t *ppos)
 237 {
 238         static DEFINE_MUTEX(dev_weight_mutex);
 239         int ret, weight;
 240
 241         mutex_lock(&dev_weight_mutex);
 242         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 243         if (!ret && write) {
 244                 weight = READ_ONCE(weight_p);
 245                 WRITE_ONCE(dev_rx_weight, weight * dev_weight_rx_bias);
 246                 WRITE_ONCE(dev_tx_weight, weight * dev_weight_tx_bias);
 247         }
 248         mutex_unlock(&dev_weight_mutex);
 249
 250         return ret;
 251 }
 252
 253 static int proc_do_rss_key(struct ctl_table *table, int write,
 254                            void *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 *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(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         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 *buffer, size_t *lenp, loff_t *ppos)
 295 {
 296         if (!capable(CAP_SYS_ADMIN))
 297                 return -EPERM;
 298
 299         return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 300 }
 301 # endif /* CONFIG_HAVE_EBPF_JIT */
 302
 303 static int
 304 proc_dolongvec_minmax_bpf_restricted(struct ctl_table *table, int write,
 305                                      void *buffer, size_t *lenp, loff_t *ppos)
 306 {
 307         if (!capable(CAP_SYS_ADMIN))
 308                 return -EPERM;
 309
 310         return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
 311 }
 312 #endif
 313
 314 static struct ctl_table net_core_table[] = {
 315 #ifdef CONFIG_NET
 316         {
 317                 .procname       = "wmem_max",
 318                 .data           = &sysctl_wmem_max,
 319                 .maxlen         = sizeof(int),
 320                 .mode           = 0644,
 321                 .proc_handler   = proc_dointvec_minmax,
 322                 .extra1         = &min_sndbuf,
 323         },
 324         {
 325                 .procname       = "rmem_max",
 326                 .data           = &sysctl_rmem_max,
 327                 .maxlen         = sizeof(int),
 328                 .mode           = 0644,
 329                 .proc_handler   = proc_dointvec_minmax,
 330                 .extra1         = &min_rcvbuf,
 331         },
 332         {
 333                 .procname       = "wmem_default",
 334                 .data           = &sysctl_wmem_default,
 335                 .maxlen         = sizeof(int),
 336                 .mode           = 0644,
 337                 .proc_handler   = proc_dointvec_minmax,
 338                 .extra1         = &min_sndbuf,
 339         },
 340         {
 341                 .procname       = "rmem_default",
 342                 .data           = &sysctl_rmem_default,
 343                 .maxlen         = sizeof(int),
 344                 .mode           = 0644,
 345                 .proc_handler   = proc_dointvec_minmax,
 346                 .extra1         = &min_rcvbuf,
 347         },
 348         {
 349                 .procname       = "dev_weight",
 350                 .data           = &weight_p,
 351                 .maxlen         = sizeof(int),
 352                 .mode           = 0644,
 353                 .proc_handler   = proc_do_dev_weight,
 354         },
 355         {
 356                 .procname       = "dev_weight_rx_bias",
 357                 .data           = &dev_weight_rx_bias,
 358                 .maxlen         = sizeof(int),
 359                 .mode           = 0644,
 360                 .proc_handler   = proc_do_dev_weight,
 361         },
 362         {
 363                 .procname       = "dev_weight_tx_bias",
 364                 .data           = &dev_weight_tx_bias,
 365                 .maxlen         = sizeof(int),
 366                 .mode           = 0644,
 367                 .proc_handler   = proc_do_dev_weight,
 368         },
 369         {
 370                 .procname       = "netdev_max_backlog",
 371                 .data           = &netdev_max_backlog,
 372                 .maxlen         = sizeof(int),
 373                 .mode           = 0644,
 374                 .proc_handler   = proc_dointvec
 375         },
 376         {
 377                 .procname       = "netdev_rss_key",
 378                 .data           = &netdev_rss_key,
 379                 .maxlen         = sizeof(int),
 380                 .mode           = 0444,
 381                 .proc_handler   = proc_do_rss_key,
 382         },
 383 #ifdef CONFIG_BPF_JIT
 384         {
 385                 .procname       = "bpf_jit_enable",
 386                 .data           = &bpf_jit_enable,
 387                 .maxlen         = sizeof(int),
 388                 .mode           = 0644,
 389                 .proc_handler   = proc_dointvec_minmax_bpf_enable,
 390 # ifdef CONFIG_BPF_JIT_ALWAYS_ON
 391                 .extra1         = SYSCTL_ONE,
 392                 .extra2         = SYSCTL_ONE,
 393 # else
 394                 .extra1         = SYSCTL_ZERO,
 395                 .extra2         = &two,
 396 # endif
 397         },
 398 # ifdef CONFIG_HAVE_EBPF_JIT
 399         {
 400                 .procname       = "bpf_jit_harden",
 401                 .data           = &bpf_jit_harden,
 402                 .maxlen         = sizeof(int),
 403                 .mode           = 0600,
 404                 .proc_handler   = proc_dointvec_minmax_bpf_restricted,
 405                 .extra1         = SYSCTL_ZERO,
 406                 .extra2         = &two,
 407         },
 408         {
 409                 .procname       = "bpf_jit_kallsyms",
 410                 .data           = &bpf_jit_kallsyms,
 411                 .maxlen         = sizeof(int),
 412                 .mode           = 0600,
 413                 .proc_handler   = proc_dointvec_minmax_bpf_restricted,
 414                 .extra1         = SYSCTL_ZERO,
 415                 .extra2         = SYSCTL_ONE,
 416         },
 417 # endif
 418         {
 419                 .procname       = "bpf_jit_limit",
 420                 .data           = &bpf_jit_limit,
 421                 .maxlen         = sizeof(long),
 422                 .mode           = 0600,
 423                 .proc_handler   = proc_dolongvec_minmax_bpf_restricted,
 424                 .extra1         = &long_one,
 425                 .extra2         = &bpf_jit_limit_max,
 426         },
 427 #endif
 428         {
 429                 .procname       = "netdev_tstamp_prequeue",
 430                 .data           = &netdev_tstamp_prequeue,
 431                 .maxlen         = sizeof(int),
 432                 .mode           = 0644,
 433                 .proc_handler   = proc_dointvec
 434         },
 435         {
 436                 .procname       = "message_cost",
 437                 .data           = &net_ratelimit_state.interval,
 438                 .maxlen         = sizeof(int),
 439                 .mode           = 0644,
 440                 .proc_handler   = proc_dointvec_jiffies,
 441         },
 442         {
 443                 .procname       = "message_burst",
 444                 .data           = &net_ratelimit_state.burst,
 445                 .maxlen         = sizeof(int),
 446                 .mode           = 0644,
 447                 .proc_handler   = proc_dointvec,
 448         },
 449         {
 450                 .procname       = "optmem_max",
 451                 .data           = &sysctl_optmem_max,
 452                 .maxlen         = sizeof(int),
 453                 .mode           = 0644,
 454                 .proc_handler   = proc_dointvec
 455         },
 456         {
 457                 .procname       = "tstamp_allow_data",
 458                 .data           = &sysctl_tstamp_allow_data,
 459                 .maxlen         = sizeof(int),
 460                 .mode           = 0644,
 461                 .proc_handler   = proc_dointvec_minmax,
 462                 .extra1         = SYSCTL_ZERO,
 463                 .extra2         = SYSCTL_ONE
 464         },
 465 #ifdef CONFIG_RPS
 466         {
 467                 .procname       = "rps_sock_flow_entries",
 468                 .maxlen         = sizeof(int),
 469                 .mode           = 0644,
 470                 .proc_handler   = rps_sock_flow_sysctl
 471         },
 472 #endif
 473 #ifdef CONFIG_NET_FLOW_LIMIT
 474         {
 475                 .procname       = "flow_limit_cpu_bitmap",
 476                 .mode           = 0644,
 477                 .proc_handler   = flow_limit_cpu_sysctl
 478         },
 479         {
 480                 .procname       = "flow_limit_table_len",
 481                 .data           = &netdev_flow_limit_table_len,
 482                 .maxlen         = sizeof(int),
 483                 .mode           = 0644,
 484                 .proc_handler   = flow_limit_table_len_sysctl
 485         },
 486 #endif /* CONFIG_NET_FLOW_LIMIT */
 487 #ifdef CONFIG_NET_RX_BUSY_POLL
 488         {
 489                 .procname       = "busy_poll",
 490                 .data           = &sysctl_net_busy_poll,
 491                 .maxlen         = sizeof(unsigned int),
 492                 .mode           = 0644,
 493                 .proc_handler   = proc_dointvec_minmax,
 494                 .extra1         = SYSCTL_ZERO,
 495         },
 496         {
 497                 .procname       = "busy_read",
 498                 .data           = &sysctl_net_busy_read,
 499                 .maxlen         = sizeof(unsigned int),
 500                 .mode           = 0644,
 501                 .proc_handler   = proc_dointvec_minmax,
 502                 .extra1         = SYSCTL_ZERO,
 503         },
 504 #endif
 505 #ifdef CONFIG_NET_SCHED
 506         {
 507                 .procname       = "default_qdisc",
 508                 .mode           = 0644,
 509                 .maxlen         = IFNAMSIZ,
 510                 .proc_handler   = set_default_qdisc
 511         },
 512 #endif
 513 #endif /* CONFIG_NET */
 514         {
 515                 .procname       = "netdev_budget",
 516                 .data           = &netdev_budget,
 517                 .maxlen         = sizeof(int),
 518                 .mode           = 0644,
 519                 .proc_handler   = proc_dointvec
 520         },
 521         {
 522                 .procname       = "warnings",
 523                 .data           = &net_msg_warn,
 524                 .maxlen         = sizeof(int),
 525                 .mode           = 0644,
 526                 .proc_handler   = proc_dointvec
 527         },
 528         {
 529                 .procname       = "max_skb_frags",
 530                 .data           = &sysctl_max_skb_frags,
 531                 .maxlen         = sizeof(int),
 532                 .mode           = 0644,
 533                 .proc_handler   = proc_dointvec_minmax,
 534                 .extra1         = SYSCTL_ONE,
 535                 .extra2         = &max_skb_frags,
 536         },
 537         {
 538                 .procname       = "netdev_budget_usecs",
 539                 .data           = &netdev_budget_usecs,
 540                 .maxlen         = sizeof(unsigned int),
 541                 .mode           = 0644,
 542                 .proc_handler   = proc_dointvec_minmax,
 543                 .extra1         = SYSCTL_ZERO,
 544         },
 545         {
 546                 .procname       = "fb_tunnels_only_for_init_net",
 547                 .data           = &sysctl_fb_tunnels_only_for_init_net,
 548                 .maxlen         = sizeof(int),
 549                 .mode           = 0644,
 550                 .proc_handler   = proc_dointvec_minmax,
 551                 .extra1         = SYSCTL_ZERO,
 552                 .extra2         = &two,
 553         },
 554         {
 555                 .procname       = "devconf_inherit_init_net",
 556                 .data           = &sysctl_devconf_inherit_init_net,
 557                 .maxlen         = sizeof(int),
 558                 .mode           = 0644,
 559                 .proc_handler   = proc_dointvec_minmax,
 560                 .extra1         = SYSCTL_ZERO,
 561                 .extra2         = &three,
 562         },
 563         {
 564                 .procname       = "high_order_alloc_disable",
 565                 .data           = &net_high_order_alloc_disable_key.key,
 566                 .maxlen         = sizeof(net_high_order_alloc_disable_key),
 567                 .mode           = 0644,
 568                 .proc_handler   = proc_do_static_key,
 569         },
 570         {
 571                 .procname       = "gro_normal_batch",
 572                 .data           = &gro_normal_batch,
 573                 .maxlen         = sizeof(unsigned int),
 574                 .mode           = 0644,
 575                 .proc_handler   = proc_dointvec_minmax,
 576                 .extra1         = SYSCTL_ONE,
 577         },
 578         { }
 579 };
 580
 581 static struct ctl_table netns_core_table[] = {
 582         {
 583                 .procname       = "somaxconn",
 584                 .data           = &init_net.core.sysctl_somaxconn,
 585                 .maxlen         = sizeof(int),
 586                 .mode           = 0644,
 587                 .extra1         = SYSCTL_ZERO,
 588                 .proc_handler   = proc_dointvec_minmax
 589         },
 590         { }
 591 };
 592
 593 static int __init fb_tunnels_only_for_init_net_sysctl_setup(char *str)
 594 {
 595         /* fallback tunnels for initns only */
 596         if (!strncmp(str, "initns", 6))
 597                 sysctl_fb_tunnels_only_for_init_net = 1;
 598         /* no fallback tunnels anywhere */
 599         else if (!strncmp(str, "none", 4))
 600                 sysctl_fb_tunnels_only_for_init_net = 2;
 601
 602         return 1;
 603 }
 604 __setup("fb_tunnels=", fb_tunnels_only_for_init_net_sysctl_setup);
 605
 606 static __net_init int sysctl_core_net_init(struct net *net)
 607 {
 608         struct ctl_table *tbl;
 609
 610         tbl = netns_core_table;
 611         if (!net_eq(net, &init_net)) {
 612                 tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);
 613                 if (tbl == NULL)
 614                         goto err_dup;
 615
 616                 tbl[0].data = &net->core.sysctl_somaxconn;
 617
 618                 /* Don't export any sysctls to unprivileged users */
 619                 if (net->user_ns != &init_user_ns) {
 620                         tbl[0].procname = NULL;
 621                 }
 622         }
 623
 624         net->core.sysctl_hdr = register_net_sysctl(net, "net/core", tbl);
 625         if (net->core.sysctl_hdr == NULL)
 626                 goto err_reg;
 627
 628         return 0;
 629
 630 err_reg:
 631         if (tbl != netns_core_table)
 632                 kfree(tbl);
 633 err_dup:
 634         return -ENOMEM;
 635 }
 636
 637 static __net_exit void sysctl_core_net_exit(struct net *net)
 638 {
 639         struct ctl_table *tbl;
 640
 641         tbl = net->core.sysctl_hdr->ctl_table_arg;
 642         unregister_net_sysctl_table(net->core.sysctl_hdr);
 643         BUG_ON(tbl == netns_core_table);
 644         kfree(tbl);
 645 }
 646
 647 static __net_initdata struct pernet_operations sysctl_core_ops = {
 648         .init = sysctl_core_net_init,
 649         .exit = sysctl_core_net_exit,
 650 };
 651
 652 static __init int sysctl_core_init(void)
 653 {
 654         register_net_sysctl(&init_net, "net/core", net_core_table);
 655         return register_pernet_subsys(&sysctl_core_ops);
 656 }
 657
 658 fs_initcall(sysctl_core_init);