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/filter.h>
  10 #include <linux/mm.h>
  11 #include <linux/sysctl.h>
  12 #include <linux/module.h>
  13 #include <linux/socket.h>
  14 #include <linux/netdevice.h>
  15 #include <linux/ratelimit.h>
  16 #include <linux/vmalloc.h>
  17 #include <linux/init.h>
  18 #include <linux/slab.h>
  19
  20 #include <net/ip.h>
  21 #include <net/sock.h>
  22 #include <net/net_ratelimit.h>
  23 #include <net/busy_poll.h>
  24 #include <net/pkt_sched.h>
  25
  26 #include "dev.h"
  27
  28 static int int_3600 = 3600;
  29 static int min_sndbuf = SOCK_MIN_SNDBUF;
  30 static int min_rcvbuf = SOCK_MIN_RCVBUF;
  31 static int max_skb_frags = MAX_SKB_FRAGS;
  32 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                                 kvfree_rcu(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                                 kfree_rcu(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                 memcpy(buffer, kbuf, len);
 184                 *lenp = len;
 185                 *ppos += len;
 186         }
 187
 188 done:
 189         free_cpumask_var(mask);
 190         return ret;
 191 }
 192
 193 static int flow_limit_table_len_sysctl(struct ctl_table *table, int write,
 194                                        void *buffer, size_t *lenp, loff_t *ppos)
 195 {
 196         unsigned int old, *ptr;
 197         int ret;
 198
 199         mutex_lock(&flow_limit_update_mutex);
 200
 201         ptr = table->data;
 202         old = *ptr;
 203         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 204         if (!ret && write && !is_power_of_2(*ptr)) {
 205                 *ptr = old;
 206                 ret = -EINVAL;
 207         }
 208
 209         mutex_unlock(&flow_limit_update_mutex);
 210         return ret;
 211 }
 212 #endif /* CONFIG_NET_FLOW_LIMIT */
 213
 214 #ifdef CONFIG_NET_SCHED
 215 static int set_default_qdisc(struct ctl_table *table, int write,
 216                              void *buffer, size_t *lenp, loff_t *ppos)
 217 {
 218         char id[IFNAMSIZ];
 219         struct ctl_table tbl = {
 220                 .data = id,
 221                 .maxlen = IFNAMSIZ,
 222         };
 223         int ret;
 224
 225         qdisc_get_default(id, IFNAMSIZ);
 226
 227         ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
 228         if (write && ret == 0)
 229                 ret = qdisc_set_default(id);
 230         return ret;
 231 }
 232 #endif
 233
 234 static int proc_do_dev_weight(struct ctl_table *table, int write,
 235                            void *buffer, size_t *lenp, loff_t *ppos)
 236 {
 237         static DEFINE_MUTEX(dev_weight_mutex);
 238         int ret, weight;
 239
 240         mutex_lock(&dev_weight_mutex);
 241         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 242         if (!ret && write) {
 243                 weight = READ_ONCE(weight_p);
 244                 WRITE_ONCE(dev_rx_weight, weight * dev_weight_rx_bias);
 245                 WRITE_ONCE(dev_tx_weight, weight * dev_weight_tx_bias);
 246         }
 247         mutex_unlock(&dev_weight_mutex);
 248
 249         return ret;
 250 }
 251
 252 static int proc_do_rss_key(struct ctl_table *table, int write,
 253                            void *buffer, size_t *lenp, loff_t *ppos)
 254 {
 255         struct ctl_table fake_table;
 256         char buf[NETDEV_RSS_KEY_LEN * 3];
 257
 258         snprintf(buf, sizeof(buf), "%*phC", NETDEV_RSS_KEY_LEN, netdev_rss_key);
 259         fake_table.data = buf;
 260         fake_table.maxlen = sizeof(buf);
 261         return proc_dostring(&fake_table, write, buffer, lenp, ppos);
 262 }
 263
 264 #ifdef CONFIG_BPF_JIT
 265 static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write,
 266                                            void *buffer, size_t *lenp,
 267                                            loff_t *ppos)
 268 {
 269         int ret, jit_enable = *(int *)table->data;
 270         int min = *(int *)table->extra1;
 271         int max = *(int *)table->extra2;
 272         struct ctl_table tmp = *table;
 273
 274         if (write && !capable(CAP_SYS_ADMIN))
 275                 return -EPERM;
 276
 277         tmp.data = &jit_enable;
 278         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
 279         if (write && !ret) {
 280                 if (jit_enable < 2 ||
 281                     (jit_enable == 2 && bpf_dump_raw_ok(current_cred()))) {
 282                         *(int *)table->data = jit_enable;
 283                         if (jit_enable == 2)
 284                                 pr_warn("bpf_jit_enable = 2 was set! NEVER use this in production, only for JIT debugging!\n");
 285                 } else {
 286                         ret = -EPERM;
 287                 }
 288         }
 289
 290         if (write && ret && min == max)
 291                 pr_info_once("CONFIG_BPF_JIT_ALWAYS_ON is enabled, bpf_jit_enable is permanently set to 1.\n");
 292
 293         return ret;
 294 }
 295
 296 # ifdef CONFIG_HAVE_EBPF_JIT
 297 static int
 298 proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
 299                                     void *buffer, size_t *lenp, loff_t *ppos)
 300 {
 301         if (!capable(CAP_SYS_ADMIN))
 302                 return -EPERM;
 303
 304         return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 305 }
 306 # endif /* CONFIG_HAVE_EBPF_JIT */
 307
 308 static int
 309 proc_dolongvec_minmax_bpf_restricted(struct ctl_table *table, int write,
 310                                      void *buffer, size_t *lenp, loff_t *ppos)
 311 {
 312         if (!capable(CAP_SYS_ADMIN))
 313                 return -EPERM;
 314
 315         return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
 316 }
 317 #endif
 318
 319 static struct ctl_table net_core_table[] = {
 320         {
 321                 .procname       = "wmem_max",
 322                 .data           = &sysctl_wmem_max,
 323                 .maxlen         = sizeof(int),
 324                 .mode           = 0644,
 325                 .proc_handler   = proc_dointvec_minmax,
 326                 .extra1         = &min_sndbuf,
 327         },
 328         {
 329                 .procname       = "rmem_max",
 330                 .data           = &sysctl_rmem_max,
 331                 .maxlen         = sizeof(int),
 332                 .mode           = 0644,
 333                 .proc_handler   = proc_dointvec_minmax,
 334                 .extra1         = &min_rcvbuf,
 335         },
 336         {
 337                 .procname       = "wmem_default",
 338                 .data           = &sysctl_wmem_default,
 339                 .maxlen         = sizeof(int),
 340                 .mode           = 0644,
 341                 .proc_handler   = proc_dointvec_minmax,
 342                 .extra1         = &min_sndbuf,
 343         },
 344         {
 345                 .procname       = "rmem_default",
 346                 .data           = &sysctl_rmem_default,
 347                 .maxlen         = sizeof(int),
 348                 .mode           = 0644,
 349                 .proc_handler   = proc_dointvec_minmax,
 350                 .extra1         = &min_rcvbuf,
 351         },
 352         {
 353                 .procname       = "dev_weight",
 354                 .data           = &weight_p,
 355                 .maxlen         = sizeof(int),
 356                 .mode           = 0644,
 357                 .proc_handler   = proc_do_dev_weight,
 358         },
 359         {
 360                 .procname       = "dev_weight_rx_bias",
 361                 .data           = &dev_weight_rx_bias,
 362                 .maxlen         = sizeof(int),
 363                 .mode           = 0644,
 364                 .proc_handler   = proc_do_dev_weight,
 365         },
 366         {
 367                 .procname       = "dev_weight_tx_bias",
 368                 .data           = &dev_weight_tx_bias,
 369                 .maxlen         = sizeof(int),
 370                 .mode           = 0644,
 371                 .proc_handler   = proc_do_dev_weight,
 372         },
 373         {
 374                 .procname       = "netdev_max_backlog",
 375                 .data           = &netdev_max_backlog,
 376                 .maxlen         = sizeof(int),
 377                 .mode           = 0644,
 378                 .proc_handler   = proc_dointvec
 379         },
 380         {
 381                 .procname       = "netdev_rss_key",
 382                 .data           = &netdev_rss_key,
 383                 .maxlen         = sizeof(int),
 384                 .mode           = 0444,
 385                 .proc_handler   = proc_do_rss_key,
 386         },
 387 #ifdef CONFIG_BPF_JIT
 388         {
 389                 .procname       = "bpf_jit_enable",
 390                 .data           = &bpf_jit_enable,
 391                 .maxlen         = sizeof(int),
 392                 .mode           = 0644,
 393                 .proc_handler   = proc_dointvec_minmax_bpf_enable,
 394 # ifdef CONFIG_BPF_JIT_ALWAYS_ON
 395                 .extra1         = SYSCTL_ONE,
 396                 .extra2         = SYSCTL_ONE,
 397 # else
 398                 .extra1         = SYSCTL_ZERO,
 399                 .extra2         = SYSCTL_TWO,
 400 # endif
 401         },
 402 # ifdef CONFIG_HAVE_EBPF_JIT
 403         {
 404                 .procname       = "bpf_jit_harden",
 405                 .data           = &bpf_jit_harden,
 406                 .maxlen         = sizeof(int),
 407                 .mode           = 0600,
 408                 .proc_handler   = proc_dointvec_minmax_bpf_restricted,
 409                 .extra1         = SYSCTL_ZERO,
 410                 .extra2         = SYSCTL_TWO,
 411         },
 412         {
 413                 .procname       = "bpf_jit_kallsyms",
 414                 .data           = &bpf_jit_kallsyms,
 415                 .maxlen         = sizeof(int),
 416                 .mode           = 0600,
 417                 .proc_handler   = proc_dointvec_minmax_bpf_restricted,
 418                 .extra1         = SYSCTL_ZERO,
 419                 .extra2         = SYSCTL_ONE,
 420         },
 421 # endif
 422         {
 423                 .procname       = "bpf_jit_limit",
 424                 .data           = &bpf_jit_limit,
 425                 .maxlen         = sizeof(long),
 426                 .mode           = 0600,
 427                 .proc_handler   = proc_dolongvec_minmax_bpf_restricted,
 428                 .extra1         = SYSCTL_LONG_ONE,
 429                 .extra2         = &bpf_jit_limit_max,
 430         },
 431 #endif
 432         {
 433                 .procname       = "netdev_tstamp_prequeue",
 434                 .data           = &netdev_tstamp_prequeue,
 435                 .maxlen         = sizeof(int),
 436                 .mode           = 0644,
 437                 .proc_handler   = proc_dointvec
 438         },
 439         {
 440                 .procname       = "message_cost",
 441                 .data           = &net_ratelimit_state.interval,
 442                 .maxlen         = sizeof(int),
 443                 .mode           = 0644,
 444                 .proc_handler   = proc_dointvec_jiffies,
 445         },
 446         {
 447                 .procname       = "message_burst",
 448                 .data           = &net_ratelimit_state.burst,
 449                 .maxlen         = sizeof(int),
 450                 .mode           = 0644,
 451                 .proc_handler   = proc_dointvec,
 452         },
 453         {
 454                 .procname       = "optmem_max",
 455                 .data           = &sysctl_optmem_max,
 456                 .maxlen         = sizeof(int),
 457                 .mode           = 0644,
 458                 .proc_handler   = proc_dointvec
 459         },
 460         {
 461                 .procname       = "tstamp_allow_data",
 462                 .data           = &sysctl_tstamp_allow_data,
 463                 .maxlen         = sizeof(int),
 464                 .mode           = 0644,
 465                 .proc_handler   = proc_dointvec_minmax,
 466                 .extra1         = SYSCTL_ZERO,
 467                 .extra2         = SYSCTL_ONE
 468         },
 469 #ifdef CONFIG_RPS
 470         {
 471                 .procname       = "rps_sock_flow_entries",
 472                 .maxlen         = sizeof(int),
 473                 .mode           = 0644,
 474                 .proc_handler   = rps_sock_flow_sysctl
 475         },
 476 #endif
 477 #ifdef CONFIG_NET_FLOW_LIMIT
 478         {
 479                 .procname       = "flow_limit_cpu_bitmap",
 480                 .mode           = 0644,
 481                 .proc_handler   = flow_limit_cpu_sysctl
 482         },
 483         {
 484                 .procname       = "flow_limit_table_len",
 485                 .data           = &netdev_flow_limit_table_len,
 486                 .maxlen         = sizeof(int),
 487                 .mode           = 0644,
 488                 .proc_handler   = flow_limit_table_len_sysctl
 489         },
 490 #endif /* CONFIG_NET_FLOW_LIMIT */
 491 #ifdef CONFIG_NET_RX_BUSY_POLL
 492         {
 493                 .procname       = "busy_poll",
 494                 .data           = &sysctl_net_busy_poll,
 495                 .maxlen         = sizeof(unsigned int),
 496                 .mode           = 0644,
 497                 .proc_handler   = proc_dointvec_minmax,
 498                 .extra1         = SYSCTL_ZERO,
 499         },
 500         {
 501                 .procname       = "busy_read",
 502                 .data           = &sysctl_net_busy_read,
 503                 .maxlen         = sizeof(unsigned int),
 504                 .mode           = 0644,
 505                 .proc_handler   = proc_dointvec_minmax,
 506                 .extra1         = SYSCTL_ZERO,
 507         },
 508 #endif
 509 #ifdef CONFIG_NET_SCHED
 510         {
 511                 .procname       = "default_qdisc",
 512                 .mode           = 0644,
 513                 .maxlen         = IFNAMSIZ,
 514                 .proc_handler   = set_default_qdisc
 515         },
 516 #endif
 517         {
 518                 .procname       = "netdev_budget",
 519                 .data           = &netdev_budget,
 520                 .maxlen         = sizeof(int),
 521                 .mode           = 0644,
 522                 .proc_handler   = proc_dointvec
 523         },
 524         {
 525                 .procname       = "warnings",
 526                 .data           = &net_msg_warn,
 527                 .maxlen         = sizeof(int),
 528                 .mode           = 0644,
 529                 .proc_handler   = proc_dointvec
 530         },
 531         {
 532                 .procname       = "max_skb_frags",
 533                 .data           = &sysctl_max_skb_frags,
 534                 .maxlen         = sizeof(int),
 535                 .mode           = 0644,
 536                 .proc_handler   = proc_dointvec_minmax,
 537                 .extra1         = SYSCTL_ONE,
 538                 .extra2         = &max_skb_frags,
 539         },
 540         {
 541                 .procname       = "netdev_budget_usecs",
 542                 .data           = &netdev_budget_usecs,
 543                 .maxlen         = sizeof(unsigned int),
 544                 .mode           = 0644,
 545                 .proc_handler   = proc_dointvec_minmax,
 546                 .extra1         = SYSCTL_ZERO,
 547         },
 548         {
 549                 .procname       = "fb_tunnels_only_for_init_net",
 550                 .data           = &sysctl_fb_tunnels_only_for_init_net,
 551                 .maxlen         = sizeof(int),
 552                 .mode           = 0644,
 553                 .proc_handler   = proc_dointvec_minmax,
 554                 .extra1         = SYSCTL_ZERO,
 555                 .extra2         = SYSCTL_TWO,
 556         },
 557         {
 558                 .procname       = "devconf_inherit_init_net",
 559                 .data           = &sysctl_devconf_inherit_init_net,
 560                 .maxlen         = sizeof(int),
 561                 .mode           = 0644,
 562                 .proc_handler   = proc_dointvec_minmax,
 563                 .extra1         = SYSCTL_ZERO,
 564                 .extra2         = SYSCTL_THREE,
 565         },
 566         {
 567                 .procname       = "high_order_alloc_disable",
 568                 .data           = &net_high_order_alloc_disable_key.key,
 569                 .maxlen         = sizeof(net_high_order_alloc_disable_key),
 570                 .mode           = 0644,
 571                 .proc_handler   = proc_do_static_key,
 572         },
 573         {
 574                 .procname       = "gro_normal_batch",
 575                 .data           = &gro_normal_batch,
 576                 .maxlen         = sizeof(unsigned int),
 577                 .mode           = 0644,
 578                 .proc_handler   = proc_dointvec_minmax,
 579                 .extra1         = SYSCTL_ONE,
 580         },
 581         {
 582                 .procname       = "netdev_unregister_timeout_secs",
 583                 .data           = &netdev_unregister_timeout_secs,
 584                 .maxlen         = sizeof(unsigned int),
 585                 .mode           = 0644,
 586                 .proc_handler   = proc_dointvec_minmax,
 587                 .extra1         = SYSCTL_ONE,
 588                 .extra2         = &int_3600,
 589         },
 590         {
 591                 .procname       = "skb_defer_max",
 592                 .data           = &sysctl_skb_defer_max,
 593                 .maxlen         = sizeof(unsigned int),
 594                 .mode           = 0644,
 595                 .proc_handler   = proc_dointvec_minmax,
 596                 .extra1         = SYSCTL_ZERO,
 597         },
 598         { }
 599 };
 600
 601 static struct ctl_table netns_core_table[] = {
 602         {
 603                 .procname       = "somaxconn",
 604                 .data           = &init_net.core.sysctl_somaxconn,
 605                 .maxlen         = sizeof(int),
 606                 .mode           = 0644,
 607                 .extra1         = SYSCTL_ZERO,
 608                 .proc_handler   = proc_dointvec_minmax
 609         },
 610         {
 611                 .procname       = "txrehash",
 612                 .data           = &init_net.core.sysctl_txrehash,
 613                 .maxlen         = sizeof(u8),
 614                 .mode           = 0644,
 615                 .extra1         = SYSCTL_ZERO,
 616                 .extra2         = SYSCTL_ONE,
 617                 .proc_handler   = proc_dou8vec_minmax,
 618         },
 619         { }
 620 };
 621
 622 static int __init fb_tunnels_only_for_init_net_sysctl_setup(char *str)
 623 {
 624         /* fallback tunnels for initns only */
 625         if (!strncmp(str, "initns", 6))
 626                 sysctl_fb_tunnels_only_for_init_net = 1;
 627         /* no fallback tunnels anywhere */
 628         else if (!strncmp(str, "none", 4))
 629                 sysctl_fb_tunnels_only_for_init_net = 2;
 630
 631         return 1;
 632 }
 633 __setup("fb_tunnels=", fb_tunnels_only_for_init_net_sysctl_setup);
 634
 635 static __net_init int sysctl_core_net_init(struct net *net)
 636 {
 637         struct ctl_table *tbl, *tmp;
 638
 639         tbl = netns_core_table;
 640         if (!net_eq(net, &init_net)) {
 641                 tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);
 642                 if (tbl == NULL)
 643                         goto err_dup;
 644
 645                 for (tmp = tbl; tmp->procname; tmp++)
 646                         tmp->data += (char *)net - (char *)&init_net;
 647
 648                 /* Don't export any sysctls to unprivileged users */
 649                 if (net->user_ns != &init_user_ns) {
 650                         tbl[0].procname = NULL;
 651                 }
 652         }
 653
 654         net->core.sysctl_hdr = register_net_sysctl(net, "net/core", tbl);
 655         if (net->core.sysctl_hdr == NULL)
 656                 goto err_reg;
 657
 658         return 0;
 659
 660 err_reg:
 661         if (tbl != netns_core_table)
 662                 kfree(tbl);
 663 err_dup:
 664         return -ENOMEM;
 665 }
 666
 667 static __net_exit void sysctl_core_net_exit(struct net *net)
 668 {
 669         struct ctl_table *tbl;
 670
 671         tbl = net->core.sysctl_hdr->ctl_table_arg;
 672         unregister_net_sysctl_table(net->core.sysctl_hdr);
 673         BUG_ON(tbl == netns_core_table);
 674         kfree(tbl);
 675 }
 676
 677 static __net_initdata struct pernet_operations sysctl_core_ops = {
 678         .init = sysctl_core_net_init,
 679         .exit = sysctl_core_net_exit,
 680 };
 681
 682 static __init int sysctl_core_init(void)
 683 {
 684         register_net_sysctl(&init_net, "net/core", net_core_table);
 685         return register_pernet_subsys(&sysctl_core_ops);
 686 }
 687
 688 fs_initcall(sysctl_core_init);