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 #include <linux/kmemleak.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 static int zero = 0;
  27 static int one = 1;
  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
  32 static int net_msg_warn;        /* Unused, but still a sysctl */
  33
  34 #ifdef CONFIG_RPS
  35 static int rps_sock_flow_sysctl(struct ctl_table *table, int write,
  36                                 void __user *buffer, size_t *lenp, loff_t *ppos)
  37 {
  38         unsigned int orig_size, size;
  39         int ret, i;
  40         struct ctl_table tmp = {
  41                 .data = &size,
  42                 .maxlen = sizeof(size),
  43                 .mode = table->mode
  44         };
  45         struct rps_sock_flow_table *orig_sock_table, *sock_table;
  46         static DEFINE_MUTEX(sock_flow_mutex);
  47
  48         mutex_lock(&sock_flow_mutex);
  49
  50         orig_sock_table = rcu_dereference_protected(rps_sock_flow_table,
  51                                         lockdep_is_held(&sock_flow_mutex));
  52         size = orig_size = orig_sock_table ? orig_sock_table->mask + 1 : 0;
  53
  54         ret = proc_dointvec(&tmp, write, buffer, lenp, ppos);
  55
  56         if (write) {
  57                 if (size) {
  58                         if (size > 1<<29) {
  59                                 /* Enforce limit to prevent overflow */
  60                                 mutex_unlock(&sock_flow_mutex);
  61                                 return -EINVAL;
  62                         }
  63                         size = roundup_pow_of_two(size);
  64                         if (size != orig_size) {
  65                                 sock_table =
  66                                     vmalloc(RPS_SOCK_FLOW_TABLE_SIZE(size));
  67                                 if (!sock_table) {
  68                                         mutex_unlock(&sock_flow_mutex);
  69                                         return -ENOMEM;
  70                                 }
  71                                 rps_cpu_mask = roundup_pow_of_two(nr_cpu_ids) - 1;
  72                                 sock_table->mask = size - 1;
  73                         } else
  74                                 sock_table = orig_sock_table;
  75
  76                         for (i = 0; i < size; i++)
  77                                 sock_table->ents[i] = RPS_NO_CPU;
  78                 } else
  79                         sock_table = NULL;
  80
  81                 if (sock_table != orig_sock_table) {
  82                         rcu_assign_pointer(rps_sock_flow_table, sock_table);
  83                         if (sock_table) {
  84                                 static_key_slow_inc(&rps_needed);
  85                                 static_key_slow_inc(&rfs_needed);
  86                         }
  87                         if (orig_sock_table) {
  88                                 static_key_slow_dec(&rps_needed);
  89                                 static_key_slow_dec(&rfs_needed);
  90                                 synchronize_rcu();
  91                                 vfree(orig_sock_table);
  92                         }
  93                 }
  94         }
  95
  96         mutex_unlock(&sock_flow_mutex);
  97
  98         return ret;
  99 }
 100 #endif /* CONFIG_RPS */
 101
 102 #ifdef CONFIG_NET_FLOW_LIMIT
 103 static DEFINE_MUTEX(flow_limit_update_mutex);
 104
 105 static int flow_limit_cpu_sysctl(struct ctl_table *table, int write,
 106                                  void __user *buffer, size_t *lenp,
 107                                  loff_t *ppos)
 108 {
 109         struct sd_flow_limit *cur;
 110         struct softnet_data *sd;
 111         cpumask_var_t mask;
 112         int i, len, ret = 0;
 113
 114         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
 115                 return -ENOMEM;
 116
 117         if (write) {
 118                 ret = cpumask_parse_user(buffer, *lenp, mask);
 119                 if (ret)
 120                         goto done;
 121
 122                 mutex_lock(&flow_limit_update_mutex);
 123                 len = sizeof(*cur) + netdev_flow_limit_table_len;
 124                 for_each_possible_cpu(i) {
 125                         sd = &per_cpu(softnet_data, i);
 126                         cur = rcu_dereference_protected(sd->flow_limit,
 127                                      lockdep_is_held(&flow_limit_update_mutex));
 128                         if (cur && !cpumask_test_cpu(i, mask)) {
 129                                 RCU_INIT_POINTER(sd->flow_limit, NULL);
 130                                 synchronize_rcu();
 131                                 kfree(cur);
 132                         } else if (!cur && cpumask_test_cpu(i, mask)) {
 133                                 cur = kzalloc_node(len, GFP_KERNEL,
 134                                                    cpu_to_node(i));
 135                                 if (!cur) {
 136                                         /* not unwinding previous changes */
 137                                         ret = -ENOMEM;
 138                                         goto write_unlock;
 139                                 }
 140                                 cur->num_buckets = netdev_flow_limit_table_len;
 141                                 rcu_assign_pointer(sd->flow_limit, cur);
 142                         }
 143                 }
 144 write_unlock:
 145                 mutex_unlock(&flow_limit_update_mutex);
 146         } else {
 147                 char kbuf[128];
 148
 149                 if (*ppos || !*lenp) {
 150                         *lenp = 0;
 151                         goto done;
 152                 }
 153
 154                 cpumask_clear(mask);
 155                 rcu_read_lock();
 156                 for_each_possible_cpu(i) {
 157                         sd = &per_cpu(softnet_data, i);
 158                         if (rcu_dereference(sd->flow_limit))
 159                                 cpumask_set_cpu(i, mask);
 160                 }
 161                 rcu_read_unlock();
 162
 163                 len = min(sizeof(kbuf) - 1, *lenp);
 164                 len = scnprintf(kbuf, len, "%*pb", cpumask_pr_args(mask));
 165                 if (!len) {
 166                         *lenp = 0;
 167                         goto done;
 168                 }
 169                 if (len < *lenp)
 170                         kbuf[len++] = '\n';
 171                 if (copy_to_user(buffer, kbuf, len)) {
 172                         ret = -EFAULT;
 173                         goto done;
 174                 }
 175                 *lenp = len;
 176                 *ppos += len;
 177         }
 178
 179 done:
 180         free_cpumask_var(mask);
 181         return ret;
 182 }
 183
 184 static int flow_limit_table_len_sysctl(struct ctl_table *table, int write,
 185                                        void __user *buffer, size_t *lenp,
 186                                        loff_t *ppos)
 187 {
 188         unsigned int old, *ptr;
 189         int ret;
 190
 191         mutex_lock(&flow_limit_update_mutex);
 192
 193         ptr = table->data;
 194         old = *ptr;
 195         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 196         if (!ret && write && !is_power_of_2(*ptr)) {
 197                 *ptr = old;
 198                 ret = -EINVAL;
 199         }
 200
 201         mutex_unlock(&flow_limit_update_mutex);
 202         return ret;
 203 }
 204 #endif /* CONFIG_NET_FLOW_LIMIT */
 205
 206 #ifdef CONFIG_NET_SCHED
 207 static int set_default_qdisc(struct ctl_table *table, int write,
 208                              void __user *buffer, size_t *lenp, loff_t *ppos)
 209 {
 210         char id[IFNAMSIZ];
 211         struct ctl_table tbl = {
 212                 .data = id,
 213                 .maxlen = IFNAMSIZ,
 214         };
 215         int ret;
 216
 217         qdisc_get_default(id, IFNAMSIZ);
 218
 219         ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
 220         if (write && ret == 0)
 221                 ret = qdisc_set_default(id);
 222         return ret;
 223 }
 224 #endif
 225
 226 static int proc_do_dev_weight(struct ctl_table *table, int write,
 227                            void __user *buffer, size_t *lenp, loff_t *ppos)
 228 {
 229         int ret;
 230
 231         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 232         if (ret != 0)
 233                 return ret;
 234
 235         dev_rx_weight = weight_p * dev_weight_rx_bias;
 236         dev_tx_weight = weight_p * dev_weight_tx_bias;
 237
 238         return ret;
 239 }
 240
 241 static int proc_do_rss_key(struct ctl_table *table, int write,
 242                            void __user *buffer, size_t *lenp, loff_t *ppos)
 243 {
 244         struct ctl_table fake_table;
 245         char buf[NETDEV_RSS_KEY_LEN * 3];
 246
 247         snprintf(buf, sizeof(buf), "%*phC", NETDEV_RSS_KEY_LEN, netdev_rss_key);
 248         fake_table.data = buf;
 249         fake_table.maxlen = sizeof(buf);
 250         return proc_dostring(&fake_table, write, buffer, lenp, ppos);
 251 }
 252
 253 static struct ctl_table net_core_table[] = {
 254 #ifdef CONFIG_NET
 255         {
 256                 .procname       = "wmem_max",
 257                 .data           = &sysctl_wmem_max,
 258                 .maxlen         = sizeof(int),
 259                 .mode           = 0644,
 260                 .proc_handler   = proc_dointvec_minmax,
 261                 .extra1         = &min_sndbuf,
 262         },
 263         {
 264                 .procname       = "rmem_max",
 265                 .data           = &sysctl_rmem_max,
 266                 .maxlen         = sizeof(int),
 267                 .mode           = 0644,
 268                 .proc_handler   = proc_dointvec_minmax,
 269                 .extra1         = &min_rcvbuf,
 270         },
 271         {
 272                 .procname       = "wmem_default",
 273                 .data           = &sysctl_wmem_default,
 274                 .maxlen         = sizeof(int),
 275                 .mode           = 0644,
 276                 .proc_handler   = proc_dointvec_minmax,
 277                 .extra1         = &min_sndbuf,
 278         },
 279         {
 280                 .procname       = "rmem_default",
 281                 .data           = &sysctl_rmem_default,
 282                 .maxlen         = sizeof(int),
 283                 .mode           = 0644,
 284                 .proc_handler   = proc_dointvec_minmax,
 285                 .extra1         = &min_rcvbuf,
 286         },
 287         {
 288                 .procname       = "dev_weight",
 289                 .data           = &weight_p,
 290                 .maxlen         = sizeof(int),
 291                 .mode           = 0644,
 292                 .proc_handler   = proc_do_dev_weight,
 293         },
 294         {
 295                 .procname       = "dev_weight_rx_bias",
 296                 .data           = &dev_weight_rx_bias,
 297                 .maxlen         = sizeof(int),
 298                 .mode           = 0644,
 299                 .proc_handler   = proc_do_dev_weight,
 300         },
 301         {
 302                 .procname       = "dev_weight_tx_bias",
 303                 .data           = &dev_weight_tx_bias,
 304                 .maxlen         = sizeof(int),
 305                 .mode           = 0644,
 306                 .proc_handler   = proc_do_dev_weight,
 307         },
 308         {
 309                 .procname       = "netdev_max_backlog",
 310                 .data           = &netdev_max_backlog,
 311                 .maxlen         = sizeof(int),
 312                 .mode           = 0644,
 313                 .proc_handler   = proc_dointvec
 314         },
 315         {
 316                 .procname       = "netdev_rss_key",
 317                 .data           = &netdev_rss_key,
 318                 .maxlen         = sizeof(int),
 319                 .mode           = 0444,
 320                 .proc_handler   = proc_do_rss_key,
 321         },
 322 #ifdef CONFIG_BPF_JIT
 323         {
 324                 .procname       = "bpf_jit_enable",
 325                 .data           = &bpf_jit_enable,
 326                 .maxlen         = sizeof(int),
 327                 .mode           = 0644,
 328 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
 329                 .proc_handler   = proc_dointvec
 330 #else
 331                 .proc_handler   = proc_dointvec_minmax,
 332                 .extra1         = &one,
 333                 .extra2         = &one,
 334 #endif
 335         },
 336 # ifdef CONFIG_HAVE_EBPF_JIT
 337         {
 338                 .procname       = "bpf_jit_harden",
 339                 .data           = &bpf_jit_harden,
 340                 .maxlen         = sizeof(int),
 341                 .mode           = 0600,
 342                 .proc_handler   = proc_dointvec,
 343         },
 344         {
 345                 .procname       = "bpf_jit_kallsyms",
 346                 .data           = &bpf_jit_kallsyms,
 347                 .maxlen         = sizeof(int),
 348                 .mode           = 0600,
 349                 .proc_handler   = proc_dointvec,
 350         },
 351 # endif
 352 #endif
 353         {
 354                 .procname       = "netdev_tstamp_prequeue",
 355                 .data           = &netdev_tstamp_prequeue,
 356                 .maxlen         = sizeof(int),
 357                 .mode           = 0644,
 358                 .proc_handler   = proc_dointvec
 359         },
 360         {
 361                 .procname       = "message_cost",
 362                 .data           = &net_ratelimit_state.interval,
 363                 .maxlen         = sizeof(int),
 364                 .mode           = 0644,
 365                 .proc_handler   = proc_dointvec_jiffies,
 366         },
 367         {
 368                 .procname       = "message_burst",
 369                 .data           = &net_ratelimit_state.burst,
 370                 .maxlen         = sizeof(int),
 371                 .mode           = 0644,
 372                 .proc_handler   = proc_dointvec,
 373         },
 374         {
 375                 .procname       = "optmem_max",
 376                 .data           = &sysctl_optmem_max,
 377                 .maxlen         = sizeof(int),
 378                 .mode           = 0644,
 379                 .proc_handler   = proc_dointvec
 380         },
 381         {
 382                 .procname       = "tstamp_allow_data",
 383                 .data           = &sysctl_tstamp_allow_data,
 384                 .maxlen         = sizeof(int),
 385                 .mode           = 0644,
 386                 .proc_handler   = proc_dointvec_minmax,
 387                 .extra1         = &zero,
 388                 .extra2         = &one
 389         },
 390 #ifdef CONFIG_RPS
 391         {
 392                 .procname       = "rps_sock_flow_entries",
 393                 .maxlen         = sizeof(int),
 394                 .mode           = 0644,
 395                 .proc_handler   = rps_sock_flow_sysctl
 396         },
 397 #endif
 398 #ifdef CONFIG_NET_FLOW_LIMIT
 399         {
 400                 .procname       = "flow_limit_cpu_bitmap",
 401                 .mode           = 0644,
 402                 .proc_handler   = flow_limit_cpu_sysctl
 403         },
 404         {
 405                 .procname       = "flow_limit_table_len",
 406                 .data           = &netdev_flow_limit_table_len,
 407                 .maxlen         = sizeof(int),
 408                 .mode           = 0644,
 409                 .proc_handler   = flow_limit_table_len_sysctl
 410         },
 411 #endif /* CONFIG_NET_FLOW_LIMIT */
 412 #ifdef CONFIG_NET_RX_BUSY_POLL
 413         {
 414                 .procname       = "busy_poll",
 415                 .data           = &sysctl_net_busy_poll,
 416                 .maxlen         = sizeof(unsigned int),
 417                 .mode           = 0644,
 418                 .proc_handler   = proc_dointvec_minmax,
 419                 .extra1         = &zero,
 420         },
 421         {
 422                 .procname       = "busy_read",
 423                 .data           = &sysctl_net_busy_read,
 424                 .maxlen         = sizeof(unsigned int),
 425                 .mode           = 0644,
 426                 .proc_handler   = proc_dointvec_minmax,
 427                 .extra1         = &zero,
 428         },
 429 #endif
 430 #ifdef CONFIG_NET_SCHED
 431         {
 432                 .procname       = "default_qdisc",
 433                 .mode           = 0644,
 434                 .maxlen         = IFNAMSIZ,
 435                 .proc_handler   = set_default_qdisc
 436         },
 437 #endif
 438 #endif /* CONFIG_NET */
 439         {
 440                 .procname       = "netdev_budget",
 441                 .data           = &netdev_budget,
 442                 .maxlen         = sizeof(int),
 443                 .mode           = 0644,
 444                 .proc_handler   = proc_dointvec
 445         },
 446         {
 447                 .procname       = "warnings",
 448                 .data           = &net_msg_warn,
 449                 .maxlen         = sizeof(int),
 450                 .mode           = 0644,
 451                 .proc_handler   = proc_dointvec
 452         },
 453         {
 454                 .procname       = "max_skb_frags",
 455                 .data           = &sysctl_max_skb_frags,
 456                 .maxlen         = sizeof(int),
 457                 .mode           = 0644,
 458                 .proc_handler   = proc_dointvec_minmax,
 459                 .extra1         = &one,
 460                 .extra2         = &max_skb_frags,
 461         },
 462         {
 463                 .procname       = "netdev_budget_usecs",
 464                 .data           = &netdev_budget_usecs,
 465                 .maxlen         = sizeof(unsigned int),
 466                 .mode           = 0644,
 467                 .proc_handler   = proc_dointvec_minmax,
 468                 .extra1         = &zero,
 469         },
 470         { }
 471 };
 472
 473 static struct ctl_table netns_core_table[] = {
 474         {
 475                 .procname       = "somaxconn",
 476                 .data           = &init_net.core.sysctl_somaxconn,
 477                 .maxlen         = sizeof(int),
 478                 .mode           = 0644,
 479                 .extra1         = &zero,
 480                 .proc_handler   = proc_dointvec_minmax
 481         },
 482         { }
 483 };
 484
 485 static __net_init int sysctl_core_net_init(struct net *net)
 486 {
 487         struct ctl_table *tbl;
 488
 489         tbl = netns_core_table;
 490         if (!net_eq(net, &init_net)) {
 491                 tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);
 492                 if (tbl == NULL)
 493                         goto err_dup;
 494
 495                 tbl[0].data = &net->core.sysctl_somaxconn;
 496
 497                 /* Don't export any sysctls to unprivileged users */
 498                 if (net->user_ns != &init_user_ns) {
 499                         tbl[0].procname = NULL;
 500                 }
 501         }
 502
 503         net->core.sysctl_hdr = register_net_sysctl(net, "net/core", tbl);
 504         if (net->core.sysctl_hdr == NULL)
 505                 goto err_reg;
 506
 507         return 0;
 508
 509 err_reg:
 510         if (tbl != netns_core_table)
 511                 kfree(tbl);
 512 err_dup:
 513         return -ENOMEM;
 514 }
 515
 516 static __net_exit void sysctl_core_net_exit(struct net *net)
 517 {
 518         struct ctl_table *tbl;
 519
 520         tbl = net->core.sysctl_hdr->ctl_table_arg;
 521         unregister_net_sysctl_table(net->core.sysctl_hdr);
 522         BUG_ON(tbl == netns_core_table);
 523         kfree(tbl);
 524 }
 525
 526 static __net_initdata struct pernet_operations sysctl_core_ops = {
 527         .init = sysctl_core_net_init,
 528         .exit = sysctl_core_net_exit,
 529 };
 530
 531 static __init int sysctl_core_init(void)
 532 {
 533         register_net_sysctl(&init_net, "net/core", net_core_table);
 534         return register_pernet_subsys(&sysctl_core_ops);
 535 }
 536
 537 fs_initcall(sysctl_core_init);