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