net/ipv4/sysctl_net_ipv4.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * sysctl_net_ipv4.c: sysctl interface to net IPV4 subsystem.
   4  *
   5  * Begun April 1, 1996, Mike Shaver.
   6  * Added /proc/sys/net/ipv4 directory entry (empty =) ). [MS]
   7  */
   8
   9 #include <linux/mm.h>
  10 #include <linux/module.h>
  11 #include <linux/sysctl.h>
  12 #include <linux/igmp.h>
  13 #include <linux/inetdevice.h>
  14 #include <linux/seqlock.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <linux/nsproxy.h>
  18 #include <linux/swap.h>
  19 #include <net/snmp.h>
  20 #include <net/icmp.h>
  21 #include <net/ip.h>
  22 #include <net/route.h>
  23 #include <net/tcp.h>
  24 #include <net/udp.h>
  25 #include <net/cipso_ipv4.h>
  26 #include <net/inet_frag.h>
  27 #include <net/ping.h>
  28 #include <net/protocol.h>
  29
  30 static int zero;
  31 static int one = 1;
  32 static int four = 4;
  33 static int thousand = 1000;
  34 static int gso_max_segs = GSO_MAX_SEGS;
  35 static int tcp_retr1_max = 255;
  36 static int ip_local_port_range_min[] = { 1, 1 };
  37 static int ip_local_port_range_max[] = { 65535, 65535 };
  38 static int tcp_adv_win_scale_min = -31;
  39 static int tcp_adv_win_scale_max = 31;
  40 static int tcp_min_snd_mss_min = TCP_MIN_SND_MSS;
  41 static int tcp_min_snd_mss_max = 65535;
  42 static int ip_privileged_port_min;
  43 static int ip_privileged_port_max = 65535;
  44 static int ip_ttl_min = 1;
  45 static int ip_ttl_max = 255;
  46 static int tcp_syn_retries_min = 1;
  47 static int tcp_syn_retries_max = MAX_TCP_SYNCNT;
  48 static int ip_ping_group_range_min[] = { 0, 0 };
  49 static int ip_ping_group_range_max[] = { GID_T_MAX, GID_T_MAX };
  50 static int one_day_secs = 24 * 3600;
  51
  52 /* obsolete */
  53 static int sysctl_tcp_low_latency __read_mostly;
  54
  55 /* Update system visible IP port range */
  56 static void set_local_port_range(struct net *net, int range[2])
  57 {
  58         bool same_parity = !((range[0] ^ range[1]) & 1);
  59
  60         write_seqlock_bh(&net->ipv4.ip_local_ports.lock);
  61         if (same_parity && !net->ipv4.ip_local_ports.warned) {
  62                 net->ipv4.ip_local_ports.warned = true;
  63                 pr_err_ratelimited("ip_local_port_range: prefer different parity for start/end values.\n");
  64         }
  65         net->ipv4.ip_local_ports.range[0] = range[0];
  66         net->ipv4.ip_local_ports.range[1] = range[1];
  67         write_sequnlock_bh(&net->ipv4.ip_local_ports.lock);
  68 }
  69
  70 /* Validate changes from /proc interface. */
  71 static int ipv4_local_port_range(struct ctl_table *table, int write,
  72                                  void __user *buffer,
  73                                  size_t *lenp, loff_t *ppos)
  74 {
  75         struct net *net =
  76                 container_of(table->data, struct net, ipv4.ip_local_ports.range);
  77         int ret;
  78         int range[2];
  79         struct ctl_table tmp = {
  80                 .data = &range,
  81                 .maxlen = sizeof(range),
  82                 .mode = table->mode,
  83                 .extra1 = &ip_local_port_range_min,
  84                 .extra2 = &ip_local_port_range_max,
  85         };
  86
  87         inet_get_local_port_range(net, &range[0], &range[1]);
  88
  89         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
  90
  91         if (write && ret == 0) {
  92                 /* Ensure that the upper limit is not smaller than the lower,
  93                  * and that the lower does not encroach upon the privileged
  94                  * port limit.
  95                  */
  96                 if ((range[1] < range[0]) ||
  97                     (range[0] < net->ipv4.sysctl_ip_prot_sock))
  98                         ret = -EINVAL;
  99                 else
 100                         set_local_port_range(net, range);
 101         }
 102
 103         return ret;
 104 }
 105
 106 /* Validate changes from /proc interface. */
 107 static int ipv4_privileged_ports(struct ctl_table *table, int write,
 108                                 void __user *buffer, size_t *lenp, loff_t *ppos)
 109 {
 110         struct net *net = container_of(table->data, struct net,
 111             ipv4.sysctl_ip_prot_sock);
 112         int ret;
 113         int pports;
 114         int range[2];
 115         struct ctl_table tmp = {
 116                 .data = &pports,
 117                 .maxlen = sizeof(pports),
 118                 .mode = table->mode,
 119                 .extra1 = &ip_privileged_port_min,
 120                 .extra2 = &ip_privileged_port_max,
 121         };
 122
 123         pports = net->ipv4.sysctl_ip_prot_sock;
 124
 125         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
 126
 127         if (write && ret == 0) {
 128                 inet_get_local_port_range(net, &range[0], &range[1]);
 129                 /* Ensure that the local port range doesn't overlap with the
 130                  * privileged port range.
 131                  */
 132                 if (range[0] < pports)
 133                         ret = -EINVAL;
 134                 else
 135                         net->ipv4.sysctl_ip_prot_sock = pports;
 136         }
 137
 138         return ret;
 139 }
 140
 141 static void inet_get_ping_group_range_table(struct ctl_table *table, kgid_t *low, kgid_t *high)
 142 {
 143         kgid_t *data = table->data;
 144         struct net *net =
 145                 container_of(table->data, struct net, ipv4.ping_group_range.range);
 146         unsigned int seq;
 147         do {
 148                 seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
 149
 150                 *low = data[0];
 151                 *high = data[1];
 152         } while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
 153 }
 154
 155 /* Update system visible IP port range */
 156 static void set_ping_group_range(struct ctl_table *table, kgid_t low, kgid_t high)
 157 {
 158         kgid_t *data = table->data;
 159         struct net *net =
 160                 container_of(table->data, struct net, ipv4.ping_group_range.range);
 161         write_seqlock(&net->ipv4.ping_group_range.lock);
 162         data[0] = low;
 163         data[1] = high;
 164         write_sequnlock(&net->ipv4.ping_group_range.lock);
 165 }
 166
 167 /* Validate changes from /proc interface. */
 168 static int ipv4_ping_group_range(struct ctl_table *table, int write,
 169                                  void __user *buffer,
 170                                  size_t *lenp, loff_t *ppos)
 171 {
 172         struct user_namespace *user_ns = current_user_ns();
 173         int ret;
 174         gid_t urange[2];
 175         kgid_t low, high;
 176         struct ctl_table tmp = {
 177                 .data = &urange,
 178                 .maxlen = sizeof(urange),
 179                 .mode = table->mode,
 180                 .extra1 = &ip_ping_group_range_min,
 181                 .extra2 = &ip_ping_group_range_max,
 182         };
 183
 184         inet_get_ping_group_range_table(table, &low, &high);
 185         urange[0] = from_kgid_munged(user_ns, low);
 186         urange[1] = from_kgid_munged(user_ns, high);
 187         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
 188
 189         if (write && ret == 0) {
 190                 low = make_kgid(user_ns, urange[0]);
 191                 high = make_kgid(user_ns, urange[1]);
 192                 if (!gid_valid(low) || !gid_valid(high))
 193                         return -EINVAL;
 194                 if (urange[1] < urange[0] || gid_lt(high, low)) {
 195                         low = make_kgid(&init_user_ns, 1);
 196                         high = make_kgid(&init_user_ns, 0);
 197                 }
 198                 set_ping_group_range(table, low, high);
 199         }
 200
 201         return ret;
 202 }
 203
 204 static int proc_tcp_congestion_control(struct ctl_table *ctl, int write,
 205                                        void __user *buffer, size_t *lenp, loff_t *ppos)
 206 {
 207         char val[TCP_CA_NAME_MAX];
 208         struct ctl_table tbl = {
 209                 .data = val,
 210                 .maxlen = TCP_CA_NAME_MAX,
 211         };
 212         int ret;
 213
 214         tcp_get_default_congestion_control(val);
 215
 216         ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
 217         if (write && ret == 0)
 218                 ret = tcp_set_default_congestion_control(val);
 219         return ret;
 220 }
 221
 222 static int proc_tcp_available_congestion_control(struct ctl_table *ctl,
 223                                                  int write,
 224                                                  void __user *buffer, size_t *lenp,
 225                                                  loff_t *ppos)
 226 {
 227         struct ctl_table tbl = { .maxlen = TCP_CA_BUF_MAX, };
 228         int ret;
 229
 230         tbl.data = kmalloc(tbl.maxlen, GFP_USER);
 231         if (!tbl.data)
 232                 return -ENOMEM;
 233         tcp_get_available_congestion_control(tbl.data, TCP_CA_BUF_MAX);
 234         ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
 235         kfree(tbl.data);
 236         return ret;
 237 }
 238
 239 static int proc_allowed_congestion_control(struct ctl_table *ctl,
 240                                            int write,
 241                                            void __user *buffer, size_t *lenp,
 242                                            loff_t *ppos)
 243 {
 244         struct ctl_table tbl = { .maxlen = TCP_CA_BUF_MAX };
 245         int ret;
 246
 247         tbl.data = kmalloc(tbl.maxlen, GFP_USER);
 248         if (!tbl.data)
 249                 return -ENOMEM;
 250
 251         tcp_get_allowed_congestion_control(tbl.data, tbl.maxlen);
 252         ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
 253         if (write && ret == 0)
 254                 ret = tcp_set_allowed_congestion_control(tbl.data);
 255         kfree(tbl.data);
 256         return ret;
 257 }
 258
 259 static int proc_tcp_fastopen_key(struct ctl_table *ctl, int write,
 260                                  void __user *buffer, size_t *lenp,
 261                                  loff_t *ppos)
 262 {
 263         struct ctl_table tbl = { .maxlen = (TCP_FASTOPEN_KEY_LENGTH * 2 + 10) };
 264         struct tcp_fastopen_context *ctxt;
 265         u32  user_key[4]; /* 16 bytes, matching TCP_FASTOPEN_KEY_LENGTH */
 266         __le32 key[4];
 267         int ret, i;
 268
 269         tbl.data = kmalloc(tbl.maxlen, GFP_KERNEL);
 270         if (!tbl.data)
 271                 return -ENOMEM;
 272
 273         rcu_read_lock();
 274         ctxt = rcu_dereference(tcp_fastopen_ctx);
 275         if (ctxt)
 276                 memcpy(key, ctxt->key, TCP_FASTOPEN_KEY_LENGTH);
 277         else
 278                 memset(key, 0, sizeof(key));
 279         rcu_read_unlock();
 280
 281         for (i = 0; i < ARRAY_SIZE(key); i++)
 282                 user_key[i] = le32_to_cpu(key[i]);
 283
 284         snprintf(tbl.data, tbl.maxlen, "%08x-%08x-%08x-%08x",
 285                 user_key[0], user_key[1], user_key[2], user_key[3]);
 286         ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
 287
 288         if (write && ret == 0) {
 289                 if (sscanf(tbl.data, "%x-%x-%x-%x", user_key, user_key + 1,
 290                            user_key + 2, user_key + 3) != 4) {
 291                         ret = -EINVAL;
 292                         goto bad_key;
 293                 }
 294                 /* Generate a dummy secret but don't publish it. This
 295                  * is needed so we don't regenerate a new key on the
 296                  * first invocation of tcp_fastopen_cookie_gen
 297                  */
 298                 tcp_fastopen_init_key_once(false);
 299
 300                 for (i = 0; i < ARRAY_SIZE(user_key); i++)
 301                         key[i] = cpu_to_le32(user_key[i]);
 302
 303                 tcp_fastopen_reset_cipher(key, TCP_FASTOPEN_KEY_LENGTH);
 304         }
 305
 306 bad_key:
 307         pr_debug("proc FO key set 0x%x-%x-%x-%x <- 0x%s: %u\n",
 308                  user_key[0], user_key[1], user_key[2], user_key[3],
 309                (char *)tbl.data, ret);
 310         kfree(tbl.data);
 311         return ret;
 312 }
 313
 314 static void proc_configure_early_demux(int enabled, int protocol)
 315 {
 316         struct net_protocol *ipprot;
 317 #if IS_ENABLED(CONFIG_IPV6)
 318         struct inet6_protocol *ip6prot;
 319 #endif
 320
 321         rcu_read_lock();
 322
 323         ipprot = rcu_dereference(inet_protos[protocol]);
 324         if (ipprot)
 325                 ipprot->early_demux = enabled ? ipprot->early_demux_handler :
 326                                                 NULL;
 327
 328 #if IS_ENABLED(CONFIG_IPV6)
 329         ip6prot = rcu_dereference(inet6_protos[protocol]);
 330         if (ip6prot)
 331                 ip6prot->early_demux = enabled ? ip6prot->early_demux_handler :
 332                                                  NULL;
 333 #endif
 334         rcu_read_unlock();
 335 }
 336
 337 static int proc_tcp_early_demux(struct ctl_table *table, int write,
 338                                 void __user *buffer, size_t *lenp, loff_t *ppos)
 339 {
 340         int ret = 0;
 341
 342         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 343
 344         if (write && !ret) {
 345                 int enabled = init_net.ipv4.sysctl_tcp_early_demux;
 346
 347                 proc_configure_early_demux(enabled, IPPROTO_TCP);
 348         }
 349
 350         return ret;
 351 }
 352
 353 static int proc_udp_early_demux(struct ctl_table *table, int write,
 354                                 void __user *buffer, size_t *lenp, loff_t *ppos)
 355 {
 356         int ret = 0;
 357
 358         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 359
 360         if (write && !ret) {
 361                 int enabled = init_net.ipv4.sysctl_udp_early_demux;
 362
 363                 proc_configure_early_demux(enabled, IPPROTO_UDP);
 364         }
 365
 366         return ret;
 367 }
 368
 369 static int proc_tfo_blackhole_detect_timeout(struct ctl_table *table,
 370                                              int write,
 371                                              void __user *buffer,
 372                                              size_t *lenp, loff_t *ppos)
 373 {
 374         int ret;
 375
 376         ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 377         if (write && ret == 0)
 378                 tcp_fastopen_active_timeout_reset();
 379
 380         return ret;
 381 }
 382
 383 static int proc_tcp_available_ulp(struct ctl_table *ctl,
 384                                   int write,
 385                                   void __user *buffer, size_t *lenp,
 386                                   loff_t *ppos)
 387 {
 388         struct ctl_table tbl = { .maxlen = TCP_ULP_BUF_MAX, };
 389         int ret;
 390
 391         tbl.data = kmalloc(tbl.maxlen, GFP_USER);
 392         if (!tbl.data)
 393                 return -ENOMEM;
 394         tcp_get_available_ulp(tbl.data, TCP_ULP_BUF_MAX);
 395         ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
 396         kfree(tbl.data);
 397
 398         return ret;
 399 }
 400
 401 static struct ctl_table ipv4_table[] = {
 402         {
 403                 .procname       = "tcp_retrans_collapse",
 404                 .data           = &sysctl_tcp_retrans_collapse,
 405                 .maxlen         = sizeof(int),
 406                 .mode           = 0644,
 407                 .proc_handler   = proc_dointvec
 408         },
 409         {
 410                 .procname       = "tcp_max_orphans",
 411                 .data           = &sysctl_tcp_max_orphans,
 412                 .maxlen         = sizeof(int),
 413                 .mode           = 0644,
 414                 .proc_handler   = proc_dointvec
 415         },
 416         {
 417                 .procname       = "tcp_fastopen",
 418                 .data           = &sysctl_tcp_fastopen,
 419                 .maxlen         = sizeof(int),
 420                 .mode           = 0644,
 421                 .proc_handler   = proc_dointvec,
 422         },
 423         {
 424                 .procname       = "tcp_fastopen_key",
 425                 .mode           = 0600,
 426                 .maxlen         = ((TCP_FASTOPEN_KEY_LENGTH * 2) + 10),
 427                 .proc_handler   = proc_tcp_fastopen_key,
 428         },
 429         {
 430                 .procname       = "tcp_fastopen_blackhole_timeout_sec",
 431                 .data           = &sysctl_tcp_fastopen_blackhole_timeout,
 432                 .maxlen         = sizeof(int),
 433                 .mode           = 0644,
 434                 .proc_handler   = proc_tfo_blackhole_detect_timeout,
 435                 .extra1         = &zero,
 436         },
 437         {
 438                 .procname       = "tcp_abort_on_overflow",
 439                 .data           = &sysctl_tcp_abort_on_overflow,
 440                 .maxlen         = sizeof(int),
 441                 .mode           = 0644,
 442                 .proc_handler   = proc_dointvec
 443         },
 444         {
 445                 .procname       = "tcp_stdurg",
 446                 .data           = &sysctl_tcp_stdurg,
 447                 .maxlen         = sizeof(int),
 448                 .mode           = 0644,
 449                 .proc_handler   = proc_dointvec
 450         },
 451         {
 452                 .procname       = "tcp_rfc1337",
 453                 .data           = &sysctl_tcp_rfc1337,
 454                 .maxlen         = sizeof(int),
 455                 .mode           = 0644,
 456                 .proc_handler   = proc_dointvec
 457         },
 458         {
 459                 .procname       = "inet_peer_threshold",
 460                 .data           = &inet_peer_threshold,
 461                 .maxlen         = sizeof(int),
 462                 .mode           = 0644,
 463                 .proc_handler   = proc_dointvec
 464         },
 465         {
 466                 .procname       = "inet_peer_minttl",
 467                 .data           = &inet_peer_minttl,
 468                 .maxlen         = sizeof(int),
 469                 .mode           = 0644,
 470                 .proc_handler   = proc_dointvec_jiffies,
 471         },
 472         {
 473                 .procname       = "inet_peer_maxttl",
 474                 .data           = &inet_peer_maxttl,
 475                 .maxlen         = sizeof(int),
 476                 .mode           = 0644,
 477                 .proc_handler   = proc_dointvec_jiffies,
 478         },
 479         {
 480                 .procname       = "tcp_fack",
 481                 .data           = &sysctl_tcp_fack,
 482                 .maxlen         = sizeof(int),
 483                 .mode           = 0644,
 484                 .proc_handler   = proc_dointvec
 485         },
 486         {
 487                 .procname       = "tcp_recovery",
 488                 .data           = &sysctl_tcp_recovery,
 489                 .maxlen         = sizeof(int),
 490                 .mode           = 0644,
 491                 .proc_handler   = proc_dointvec,
 492         },
 493         {
 494                 .procname       = "tcp_max_reordering",
 495                 .data           = &sysctl_tcp_max_reordering,
 496                 .maxlen         = sizeof(int),
 497                 .mode           = 0644,
 498                 .proc_handler   = proc_dointvec
 499         },
 500         {
 501                 .procname       = "tcp_dsack",
 502                 .data           = &sysctl_tcp_dsack,
 503                 .maxlen         = sizeof(int),
 504                 .mode           = 0644,
 505                 .proc_handler   = proc_dointvec
 506         },
 507         {
 508                 .procname       = "tcp_mem",
 509                 .maxlen         = sizeof(sysctl_tcp_mem),
 510                 .data           = &sysctl_tcp_mem,
 511                 .mode           = 0644,
 512                 .proc_handler   = proc_doulongvec_minmax,
 513         },
 514         {
 515                 .procname       = "tcp_wmem",
 516                 .data           = &sysctl_tcp_wmem,
 517                 .maxlen         = sizeof(sysctl_tcp_wmem),
 518                 .mode           = 0644,
 519                 .proc_handler   = proc_dointvec_minmax,
 520                 .extra1         = &one,
 521         },
 522         {
 523                 .procname       = "tcp_rmem",
 524                 .data           = &sysctl_tcp_rmem,
 525                 .maxlen         = sizeof(sysctl_tcp_rmem),
 526                 .mode           = 0644,
 527                 .proc_handler   = proc_dointvec_minmax,
 528                 .extra1         = &one,
 529         },
 530         {
 531                 .procname       = "tcp_app_win",
 532                 .data           = &sysctl_tcp_app_win,
 533                 .maxlen         = sizeof(int),
 534                 .mode           = 0644,
 535                 .proc_handler   = proc_dointvec
 536         },
 537         {
 538                 .procname       = "tcp_adv_win_scale",
 539                 .data           = &sysctl_tcp_adv_win_scale,
 540                 .maxlen         = sizeof(int),
 541                 .mode           = 0644,
 542                 .proc_handler   = proc_dointvec_minmax,
 543                 .extra1         = &tcp_adv_win_scale_min,
 544                 .extra2         = &tcp_adv_win_scale_max,
 545         },
 546         {
 547                 .procname       = "tcp_frto",
 548                 .data           = &sysctl_tcp_frto,
 549                 .maxlen         = sizeof(int),
 550                 .mode           = 0644,
 551                 .proc_handler   = proc_dointvec
 552         },
 553         {
 554                 .procname       = "tcp_min_rtt_wlen",
 555                 .data           = &sysctl_tcp_min_rtt_wlen,
 556                 .maxlen         = sizeof(int),
 557                 .mode           = 0644,
 558                 .proc_handler   = proc_dointvec_minmax,
 559                 .extra1         = &zero,
 560                 .extra2         = &one_day_secs
 561         },
 562         {
 563                 .procname       = "tcp_low_latency",
 564                 .data           = &sysctl_tcp_low_latency,
 565                 .maxlen         = sizeof(int),
 566                 .mode           = 0644,
 567                 .proc_handler   = proc_dointvec
 568         },
 569         {
 570                 .procname       = "tcp_no_metrics_save",
 571                 .data           = &sysctl_tcp_nometrics_save,
 572                 .maxlen         = sizeof(int),
 573                 .mode           = 0644,
 574                 .proc_handler   = proc_dointvec,
 575         },
 576         {
 577                 .procname       = "tcp_moderate_rcvbuf",
 578                 .data           = &sysctl_tcp_moderate_rcvbuf,
 579                 .maxlen         = sizeof(int),
 580                 .mode           = 0644,
 581                 .proc_handler   = proc_dointvec,
 582         },
 583         {
 584                 .procname       = "tcp_tso_win_divisor",
 585                 .data           = &sysctl_tcp_tso_win_divisor,
 586                 .maxlen         = sizeof(int),
 587                 .mode           = 0644,
 588                 .proc_handler   = proc_dointvec,
 589         },
 590         {
 591                 .procname       = "tcp_congestion_control",
 592                 .mode           = 0644,
 593                 .maxlen         = TCP_CA_NAME_MAX,
 594                 .proc_handler   = proc_tcp_congestion_control,
 595         },
 596         {
 597                 .procname       = "tcp_workaround_signed_windows",
 598                 .data           = &sysctl_tcp_workaround_signed_windows,
 599                 .maxlen         = sizeof(int),
 600                 .mode           = 0644,
 601                 .proc_handler   = proc_dointvec
 602         },
 603         {
 604                 .procname       = "tcp_limit_output_bytes",
 605                 .data           = &sysctl_tcp_limit_output_bytes,
 606                 .maxlen         = sizeof(int),
 607                 .mode           = 0644,
 608                 .proc_handler   = proc_dointvec
 609         },
 610         {
 611                 .procname       = "tcp_challenge_ack_limit",
 612                 .data           = &sysctl_tcp_challenge_ack_limit,
 613                 .maxlen         = sizeof(int),
 614                 .mode           = 0644,
 615                 .proc_handler   = proc_dointvec
 616         },
 617         {
 618                 .procname       = "tcp_slow_start_after_idle",
 619                 .data           = &sysctl_tcp_slow_start_after_idle,
 620                 .maxlen         = sizeof(int),
 621                 .mode           = 0644,
 622                 .proc_handler   = proc_dointvec
 623         },
 624 #ifdef CONFIG_NETLABEL
 625         {
 626                 .procname       = "cipso_cache_enable",
 627                 .data           = &cipso_v4_cache_enabled,
 628                 .maxlen         = sizeof(int),
 629                 .mode           = 0644,
 630                 .proc_handler   = proc_dointvec,
 631         },
 632         {
 633                 .procname       = "cipso_cache_bucket_size",
 634                 .data           = &cipso_v4_cache_bucketsize,
 635                 .maxlen         = sizeof(int),
 636                 .mode           = 0644,
 637                 .proc_handler   = proc_dointvec,
 638         },
 639         {
 640                 .procname       = "cipso_rbm_optfmt",
 641                 .data           = &cipso_v4_rbm_optfmt,
 642                 .maxlen         = sizeof(int),
 643                 .mode           = 0644,
 644                 .proc_handler   = proc_dointvec,
 645         },
 646         {
 647                 .procname       = "cipso_rbm_strictvalid",
 648                 .data           = &cipso_v4_rbm_strictvalid,
 649                 .maxlen         = sizeof(int),
 650                 .mode           = 0644,
 651                 .proc_handler   = proc_dointvec,
 652         },
 653 #endif /* CONFIG_NETLABEL */
 654         {
 655                 .procname       = "tcp_available_congestion_control",
 656                 .maxlen         = TCP_CA_BUF_MAX,
 657                 .mode           = 0444,
 658                 .proc_handler   = proc_tcp_available_congestion_control,
 659         },
 660         {
 661                 .procname       = "tcp_allowed_congestion_control",
 662                 .maxlen         = TCP_CA_BUF_MAX,
 663                 .mode           = 0644,
 664                 .proc_handler   = proc_allowed_congestion_control,
 665         },
 666         {
 667                 .procname       = "tcp_thin_linear_timeouts",
 668                 .data           = &sysctl_tcp_thin_linear_timeouts,
 669                 .maxlen         = sizeof(int),
 670                 .mode           = 0644,
 671                 .proc_handler   = proc_dointvec
 672         },
 673         {
 674                 .procname       = "tcp_early_retrans",
 675                 .data           = &sysctl_tcp_early_retrans,
 676                 .maxlen         = sizeof(int),
 677                 .mode           = 0644,
 678                 .proc_handler   = proc_dointvec_minmax,
 679                 .extra1         = &zero,
 680                 .extra2         = &four,
 681         },
 682         {
 683                 .procname       = "tcp_min_tso_segs",
 684                 .data           = &sysctl_tcp_min_tso_segs,
 685                 .maxlen         = sizeof(int),
 686                 .mode           = 0644,
 687                 .proc_handler   = proc_dointvec_minmax,
 688                 .extra1         = &one,
 689                 .extra2         = &gso_max_segs,
 690         },
 691         {
 692                 .procname       = "tcp_pacing_ss_ratio",
 693                 .data           = &sysctl_tcp_pacing_ss_ratio,
 694                 .maxlen         = sizeof(int),
 695                 .mode           = 0644,
 696                 .proc_handler   = proc_dointvec_minmax,
 697                 .extra1         = &zero,
 698                 .extra2         = &thousand,
 699         },
 700         {
 701                 .procname       = "tcp_pacing_ca_ratio",
 702                 .data           = &sysctl_tcp_pacing_ca_ratio,
 703                 .maxlen         = sizeof(int),
 704                 .mode           = 0644,
 705                 .proc_handler   = proc_dointvec_minmax,
 706                 .extra1         = &zero,
 707                 .extra2         = &thousand,
 708         },
 709         {
 710                 .procname       = "tcp_autocorking",
 711                 .data           = &sysctl_tcp_autocorking,
 712                 .maxlen         = sizeof(int),
 713                 .mode           = 0644,
 714                 .proc_handler   = proc_dointvec_minmax,
 715                 .extra1         = &zero,
 716                 .extra2         = &one,
 717         },
 718         {
 719                 .procname       = "tcp_invalid_ratelimit",
 720                 .data           = &sysctl_tcp_invalid_ratelimit,
 721                 .maxlen         = sizeof(int),
 722                 .mode           = 0644,
 723                 .proc_handler   = proc_dointvec_ms_jiffies,
 724         },
 725         {
 726                 .procname       = "tcp_available_ulp",
 727                 .maxlen         = TCP_ULP_BUF_MAX,
 728                 .mode           = 0444,
 729                 .proc_handler   = proc_tcp_available_ulp,
 730         },
 731         {
 732                 .procname       = "icmp_msgs_per_sec",
 733                 .data           = &sysctl_icmp_msgs_per_sec,
 734                 .maxlen         = sizeof(int),
 735                 .mode           = 0644,
 736                 .proc_handler   = proc_dointvec_minmax,
 737                 .extra1         = &zero,
 738         },
 739         {
 740                 .procname       = "icmp_msgs_burst",
 741                 .data           = &sysctl_icmp_msgs_burst,
 742                 .maxlen         = sizeof(int),
 743                 .mode           = 0644,
 744                 .proc_handler   = proc_dointvec_minmax,
 745                 .extra1         = &zero,
 746         },
 747         {
 748                 .procname       = "udp_mem",
 749                 .data           = &sysctl_udp_mem,
 750                 .maxlen         = sizeof(sysctl_udp_mem),
 751                 .mode           = 0644,
 752                 .proc_handler   = proc_doulongvec_minmax,
 753         },
 754         {
 755                 .procname       = "udp_rmem_min",
 756                 .data           = &sysctl_udp_rmem_min,
 757                 .maxlen         = sizeof(sysctl_udp_rmem_min),
 758                 .mode           = 0644,
 759                 .proc_handler   = proc_dointvec_minmax,
 760                 .extra1         = &one
 761         },
 762         {
 763                 .procname       = "udp_wmem_min",
 764                 .data           = &sysctl_udp_wmem_min,
 765                 .maxlen         = sizeof(sysctl_udp_wmem_min),
 766                 .mode           = 0644,
 767                 .proc_handler   = proc_dointvec_minmax,
 768                 .extra1         = &one
 769         },
 770         { }
 771 };
 772
 773 static struct ctl_table ipv4_net_table[] = {
 774         {
 775                 .procname       = "icmp_echo_ignore_all",
 776                 .data           = &init_net.ipv4.sysctl_icmp_echo_ignore_all,
 777                 .maxlen         = sizeof(int),
 778                 .mode           = 0644,
 779                 .proc_handler   = proc_dointvec
 780         },
 781         {
 782                 .procname       = "icmp_echo_ignore_broadcasts",
 783                 .data           = &init_net.ipv4.sysctl_icmp_echo_ignore_broadcasts,
 784                 .maxlen         = sizeof(int),
 785                 .mode           = 0644,
 786                 .proc_handler   = proc_dointvec
 787         },
 788         {
 789                 .procname       = "icmp_ignore_bogus_error_responses",
 790                 .data           = &init_net.ipv4.sysctl_icmp_ignore_bogus_error_responses,
 791                 .maxlen         = sizeof(int),
 792                 .mode           = 0644,
 793                 .proc_handler   = proc_dointvec
 794         },
 795         {
 796                 .procname       = "icmp_errors_use_inbound_ifaddr",
 797                 .data           = &init_net.ipv4.sysctl_icmp_errors_use_inbound_ifaddr,
 798                 .maxlen         = sizeof(int),
 799                 .mode           = 0644,
 800                 .proc_handler   = proc_dointvec
 801         },
 802         {
 803                 .procname       = "icmp_ratelimit",
 804                 .data           = &init_net.ipv4.sysctl_icmp_ratelimit,
 805                 .maxlen         = sizeof(int),
 806                 .mode           = 0644,
 807                 .proc_handler   = proc_dointvec_ms_jiffies,
 808         },
 809         {
 810                 .procname       = "icmp_ratemask",
 811                 .data           = &init_net.ipv4.sysctl_icmp_ratemask,
 812                 .maxlen         = sizeof(int),
 813                 .mode           = 0644,
 814                 .proc_handler   = proc_dointvec
 815         },
 816         {
 817                 .procname       = "ping_group_range",
 818                 .data           = &init_net.ipv4.ping_group_range.range,
 819                 .maxlen         = sizeof(gid_t)*2,
 820                 .mode           = 0644,
 821                 .proc_handler   = ipv4_ping_group_range,
 822         },
 823         {
 824                 .procname       = "tcp_ecn",
 825                 .data           = &init_net.ipv4.sysctl_tcp_ecn,
 826                 .maxlen         = sizeof(int),
 827                 .mode           = 0644,
 828                 .proc_handler   = proc_dointvec
 829         },
 830         {
 831                 .procname       = "tcp_ecn_fallback",
 832                 .data           = &init_net.ipv4.sysctl_tcp_ecn_fallback,
 833                 .maxlen         = sizeof(int),
 834                 .mode           = 0644,
 835                 .proc_handler   = proc_dointvec
 836         },
 837         {
 838                 .procname       = "ip_dynaddr",
 839                 .data           = &init_net.ipv4.sysctl_ip_dynaddr,
 840                 .maxlen         = sizeof(int),
 841                 .mode           = 0644,
 842                 .proc_handler   = proc_dointvec
 843         },
 844         {
 845                 .procname       = "ip_early_demux",
 846                 .data           = &init_net.ipv4.sysctl_ip_early_demux,
 847                 .maxlen         = sizeof(int),
 848                 .mode           = 0644,
 849                 .proc_handler   = proc_dointvec
 850         },
 851         {
 852                 .procname       = "udp_early_demux",
 853                 .data           = &init_net.ipv4.sysctl_udp_early_demux,
 854                 .maxlen         = sizeof(int),
 855                 .mode           = 0644,
 856                 .proc_handler   = proc_udp_early_demux
 857         },
 858         {
 859                 .procname       = "tcp_early_demux",
 860                 .data           = &init_net.ipv4.sysctl_tcp_early_demux,
 861                 .maxlen         = sizeof(int),
 862                 .mode           = 0644,
 863                 .proc_handler   = proc_tcp_early_demux
 864         },
 865         {
 866                 .procname       = "ip_default_ttl",
 867                 .data           = &init_net.ipv4.sysctl_ip_default_ttl,
 868                 .maxlen         = sizeof(int),
 869                 .mode           = 0644,
 870                 .proc_handler   = proc_dointvec_minmax,
 871                 .extra1         = &ip_ttl_min,
 872                 .extra2         = &ip_ttl_max,
 873         },
 874         {
 875                 .procname       = "ip_local_port_range",
 876                 .maxlen         = sizeof(init_net.ipv4.ip_local_ports.range),
 877                 .data           = &init_net.ipv4.ip_local_ports.range,
 878                 .mode           = 0644,
 879                 .proc_handler   = ipv4_local_port_range,
 880         },
 881         {
 882                 .procname       = "ip_local_reserved_ports",
 883                 .data           = &init_net.ipv4.sysctl_local_reserved_ports,
 884                 .maxlen         = 65536,
 885                 .mode           = 0644,
 886                 .proc_handler   = proc_do_large_bitmap,
 887         },
 888         {
 889                 .procname       = "ip_no_pmtu_disc",
 890                 .data           = &init_net.ipv4.sysctl_ip_no_pmtu_disc,
 891                 .maxlen         = sizeof(int),
 892                 .mode           = 0644,
 893                 .proc_handler   = proc_dointvec
 894         },
 895         {
 896                 .procname       = "ip_forward_use_pmtu",
 897                 .data           = &init_net.ipv4.sysctl_ip_fwd_use_pmtu,
 898                 .maxlen         = sizeof(int),
 899                 .mode           = 0644,
 900                 .proc_handler   = proc_dointvec,
 901         },
 902         {
 903                 .procname       = "ip_nonlocal_bind",
 904                 .data           = &init_net.ipv4.sysctl_ip_nonlocal_bind,
 905                 .maxlen         = sizeof(int),
 906                 .mode           = 0644,
 907                 .proc_handler   = proc_dointvec
 908         },
 909         {
 910                 .procname       = "fwmark_reflect",
 911                 .data           = &init_net.ipv4.sysctl_fwmark_reflect,
 912                 .maxlen         = sizeof(int),
 913                 .mode           = 0644,
 914                 .proc_handler   = proc_dointvec,
 915         },
 916         {
 917                 .procname       = "tcp_fwmark_accept",
 918                 .data           = &init_net.ipv4.sysctl_tcp_fwmark_accept,
 919                 .maxlen         = sizeof(int),
 920                 .mode           = 0644,
 921                 .proc_handler   = proc_dointvec,
 922         },
 923 #ifdef CONFIG_NET_L3_MASTER_DEV
 924         {
 925                 .procname       = "tcp_l3mdev_accept",
 926                 .data           = &init_net.ipv4.sysctl_tcp_l3mdev_accept,
 927                 .maxlen         = sizeof(int),
 928                 .mode           = 0644,
 929                 .proc_handler   = proc_dointvec_minmax,
 930                 .extra1         = &zero,
 931                 .extra2         = &one,
 932         },
 933 #endif
 934         {
 935                 .procname       = "tcp_mtu_probing",
 936                 .data           = &init_net.ipv4.sysctl_tcp_mtu_probing,
 937                 .maxlen         = sizeof(int),
 938                 .mode           = 0644,
 939                 .proc_handler   = proc_dointvec,
 940         },
 941         {
 942                 .procname       = "tcp_base_mss",
 943                 .data           = &init_net.ipv4.sysctl_tcp_base_mss,
 944                 .maxlen         = sizeof(int),
 945                 .mode           = 0644,
 946                 .proc_handler   = proc_dointvec,
 947         },
 948         {
 949                 .procname       = "tcp_min_snd_mss",
 950                 .data           = &init_net.ipv4.sysctl_tcp_min_snd_mss,
 951                 .maxlen         = sizeof(int),
 952                 .mode           = 0644,
 953                 .proc_handler   = proc_dointvec_minmax,
 954                 .extra1         = &tcp_min_snd_mss_min,
 955                 .extra2         = &tcp_min_snd_mss_max,
 956         },
 957         {
 958                 .procname       = "tcp_probe_threshold",
 959                 .data           = &init_net.ipv4.sysctl_tcp_probe_threshold,
 960                 .maxlen         = sizeof(int),
 961                 .mode           = 0644,
 962                 .proc_handler   = proc_dointvec,
 963         },
 964         {
 965                 .procname       = "tcp_probe_interval",
 966                 .data           = &init_net.ipv4.sysctl_tcp_probe_interval,
 967                 .maxlen         = sizeof(int),
 968                 .mode           = 0644,
 969                 .proc_handler   = proc_dointvec,
 970         },
 971         {
 972                 .procname       = "igmp_link_local_mcast_reports",
 973                 .data           = &init_net.ipv4.sysctl_igmp_llm_reports,
 974                 .maxlen         = sizeof(int),
 975                 .mode           = 0644,
 976                 .proc_handler   = proc_dointvec
 977         },
 978         {
 979                 .procname       = "igmp_max_memberships",
 980                 .data           = &init_net.ipv4.sysctl_igmp_max_memberships,
 981                 .maxlen         = sizeof(int),
 982                 .mode           = 0644,
 983                 .proc_handler   = proc_dointvec
 984         },
 985         {
 986                 .procname       = "igmp_max_msf",
 987                 .data           = &init_net.ipv4.sysctl_igmp_max_msf,
 988                 .maxlen         = sizeof(int),
 989                 .mode           = 0644,
 990                 .proc_handler   = proc_dointvec
 991         },
 992 #ifdef CONFIG_IP_MULTICAST
 993         {
 994                 .procname       = "igmp_qrv",
 995                 .data           = &init_net.ipv4.sysctl_igmp_qrv,
 996                 .maxlen         = sizeof(int),
 997                 .mode           = 0644,
 998                 .proc_handler   = proc_dointvec_minmax,
 999                 .extra1         = &one
1000         },
1001 #endif
1002         {
1003                 .procname       = "tcp_keepalive_time",
1004                 .data           = &init_net.ipv4.sysctl_tcp_keepalive_time,
1005                 .maxlen         = sizeof(int),
1006                 .mode           = 0644,
1007                 .proc_handler   = proc_dointvec_jiffies,
1008         },
1009         {
1010                 .procname       = "tcp_keepalive_probes",
1011                 .data           = &init_net.ipv4.sysctl_tcp_keepalive_probes,
1012                 .maxlen         = sizeof(int),
1013                 .mode           = 0644,
1014                 .proc_handler   = proc_dointvec
1015         },
1016         {
1017                 .procname       = "tcp_keepalive_intvl",
1018                 .data           = &init_net.ipv4.sysctl_tcp_keepalive_intvl,
1019                 .maxlen         = sizeof(int),
1020                 .mode           = 0644,
1021                 .proc_handler   = proc_dointvec_jiffies,
1022         },
1023         {
1024                 .procname       = "tcp_syn_retries",
1025                 .data           = &init_net.ipv4.sysctl_tcp_syn_retries,
1026                 .maxlen         = sizeof(int),
1027                 .mode           = 0644,
1028                 .proc_handler   = proc_dointvec_minmax,
1029                 .extra1         = &tcp_syn_retries_min,
1030                 .extra2         = &tcp_syn_retries_max
1031         },
1032         {
1033                 .procname       = "tcp_synack_retries",
1034                 .data           = &init_net.ipv4.sysctl_tcp_synack_retries,
1035                 .maxlen         = sizeof(int),
1036                 .mode           = 0644,
1037                 .proc_handler   = proc_dointvec
1038         },
1039 #ifdef CONFIG_SYN_COOKIES
1040         {
1041                 .procname       = "tcp_syncookies",
1042                 .data           = &init_net.ipv4.sysctl_tcp_syncookies,
1043                 .maxlen         = sizeof(int),
1044                 .mode           = 0644,
1045                 .proc_handler   = proc_dointvec
1046         },
1047 #endif
1048         {
1049                 .procname       = "tcp_reordering",
1050                 .data           = &init_net.ipv4.sysctl_tcp_reordering,
1051                 .maxlen         = sizeof(int),
1052                 .mode           = 0644,
1053                 .proc_handler   = proc_dointvec
1054         },
1055         {
1056                 .procname       = "tcp_retries1",
1057                 .data           = &init_net.ipv4.sysctl_tcp_retries1,
1058                 .maxlen         = sizeof(int),
1059                 .mode           = 0644,
1060                 .proc_handler   = proc_dointvec_minmax,
1061                 .extra2         = &tcp_retr1_max
1062         },
1063         {
1064                 .procname       = "tcp_retries2",
1065                 .data           = &init_net.ipv4.sysctl_tcp_retries2,
1066                 .maxlen         = sizeof(int),
1067                 .mode           = 0644,
1068                 .proc_handler   = proc_dointvec
1069         },
1070         {
1071                 .procname       = "tcp_orphan_retries",
1072                 .data           = &init_net.ipv4.sysctl_tcp_orphan_retries,
1073                 .maxlen         = sizeof(int),
1074                 .mode           = 0644,
1075                 .proc_handler   = proc_dointvec
1076         },
1077         {
1078                 .procname       = "tcp_fin_timeout",
1079                 .data           = &init_net.ipv4.sysctl_tcp_fin_timeout,
1080                 .maxlen         = sizeof(int),
1081                 .mode           = 0644,
1082                 .proc_handler   = proc_dointvec_jiffies,
1083         },
1084         {
1085                 .procname       = "tcp_notsent_lowat",
1086                 .data           = &init_net.ipv4.sysctl_tcp_notsent_lowat,
1087                 .maxlen         = sizeof(unsigned int),
1088                 .mode           = 0644,
1089                 .proc_handler   = proc_douintvec,
1090         },
1091         {
1092                 .procname       = "tcp_tw_reuse",
1093                 .data           = &init_net.ipv4.sysctl_tcp_tw_reuse,
1094                 .maxlen         = sizeof(int),
1095                 .mode           = 0644,
1096                 .proc_handler   = proc_dointvec
1097         },
1098         {
1099                 .procname       = "tcp_max_tw_buckets",
1100                 .data           = &init_net.ipv4.tcp_death_row.sysctl_max_tw_buckets,
1101                 .maxlen         = sizeof(int),
1102                 .mode           = 0644,
1103                 .proc_handler   = proc_dointvec
1104         },
1105         {
1106                 .procname       = "tcp_max_syn_backlog",
1107                 .data           = &init_net.ipv4.sysctl_max_syn_backlog,
1108                 .maxlen         = sizeof(int),
1109                 .mode           = 0644,
1110                 .proc_handler   = proc_dointvec
1111         },
1112 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1113         {
1114                 .procname       = "fib_multipath_use_neigh",
1115                 .data           = &init_net.ipv4.sysctl_fib_multipath_use_neigh,
1116                 .maxlen         = sizeof(int),
1117                 .mode           = 0644,
1118                 .proc_handler   = proc_dointvec_minmax,
1119                 .extra1         = &zero,
1120                 .extra2         = &one,
1121         },
1122         {
1123                 .procname       = "fib_multipath_hash_policy",
1124                 .data           = &init_net.ipv4.sysctl_fib_multipath_hash_policy,
1125                 .maxlen         = sizeof(int),
1126                 .mode           = 0644,
1127                 .proc_handler   = proc_dointvec_minmax,
1128                 .extra1         = &zero,
1129                 .extra2         = &one,
1130         },
1131 #endif
1132         {
1133                 .procname       = "ip_unprivileged_port_start",
1134                 .maxlen         = sizeof(int),
1135                 .data           = &init_net.ipv4.sysctl_ip_prot_sock,
1136                 .mode           = 0644,
1137                 .proc_handler   = ipv4_privileged_ports,
1138         },
1139 #ifdef CONFIG_NET_L3_MASTER_DEV
1140         {
1141                 .procname       = "udp_l3mdev_accept",
1142                 .data           = &init_net.ipv4.sysctl_udp_l3mdev_accept,
1143                 .maxlen         = sizeof(int),
1144                 .mode           = 0644,
1145                 .proc_handler   = proc_dointvec_minmax,
1146                 .extra1         = &zero,
1147                 .extra2         = &one,
1148         },
1149 #endif
1150         {
1151                 .procname       = "tcp_sack",
1152                 .data           = &init_net.ipv4.sysctl_tcp_sack,
1153                 .maxlen         = sizeof(int),
1154                 .mode           = 0644,
1155                 .proc_handler   = proc_dointvec
1156         },
1157         {
1158                 .procname       = "tcp_window_scaling",
1159                 .data           = &init_net.ipv4.sysctl_tcp_window_scaling,
1160                 .maxlen         = sizeof(int),
1161                 .mode           = 0644,
1162                 .proc_handler   = proc_dointvec
1163         },
1164         {
1165                 .procname       = "tcp_timestamps",
1166                 .data           = &init_net.ipv4.sysctl_tcp_timestamps,
1167                 .maxlen         = sizeof(int),
1168                 .mode           = 0644,
1169                 .proc_handler   = proc_dointvec
1170         },
1171         { }
1172 };
1173
1174 static __net_init int ipv4_sysctl_init_net(struct net *net)
1175 {
1176         struct ctl_table *table;
1177
1178         table = ipv4_net_table;
1179         if (!net_eq(net, &init_net)) {
1180                 int i;
1181
1182                 table = kmemdup(table, sizeof(ipv4_net_table), GFP_KERNEL);
1183                 if (!table)
1184                         goto err_alloc;
1185
1186                 /* Update the variables to point into the current struct net */
1187                 for (i = 0; i < ARRAY_SIZE(ipv4_net_table) - 1; i++)
1188                         table[i].data += (void *)net - (void *)&init_net;
1189         }
1190
1191         net->ipv4.ipv4_hdr = register_net_sysctl(net, "net/ipv4", table);
1192         if (!net->ipv4.ipv4_hdr)
1193                 goto err_reg;
1194
1195         net->ipv4.sysctl_local_reserved_ports = kzalloc(65536 / 8, GFP_KERNEL);
1196         if (!net->ipv4.sysctl_local_reserved_ports)
1197                 goto err_ports;
1198
1199         return 0;
1200
1201 err_ports:
1202         unregister_net_sysctl_table(net->ipv4.ipv4_hdr);
1203 err_reg:
1204         if (!net_eq(net, &init_net))
1205                 kfree(table);
1206 err_alloc:
1207         return -ENOMEM;
1208 }
1209
1210 static __net_exit void ipv4_sysctl_exit_net(struct net *net)
1211 {
1212         struct ctl_table *table;
1213
1214         kfree(net->ipv4.sysctl_local_reserved_ports);
1215         table = net->ipv4.ipv4_hdr->ctl_table_arg;
1216         unregister_net_sysctl_table(net->ipv4.ipv4_hdr);
1217         kfree(table);
1218 }
1219
1220 static __net_initdata struct pernet_operations ipv4_sysctl_ops = {
1221         .init = ipv4_sysctl_init_net,
1222         .exit = ipv4_sysctl_exit_net,
1223 };
1224
1225 static __init int sysctl_ipv4_init(void)
1226 {
1227         struct ctl_table_header *hdr;
1228
1229         hdr = register_net_sysctl(&init_net, "net/ipv4", ipv4_table);
1230         if (!hdr)
1231                 return -ENOMEM;
1232
1233         if (register_pernet_subsys(&ipv4_sysctl_ops)) {
1234                 unregister_net_sysctl_table(hdr);
1235                 return -ENOMEM;
1236         }
1237
1238         return 0;
1239 }
1240
1241 __initcall(sysctl_ipv4_init);