net/core/sysctl_net_core.c

   1 /* -*- linux-c -*-
   2  * sysctl_net_core.c: sysctl interface to net core subsystem.
   3  *
   4  * Begun April 1, 1996, Mike Shaver.
   5  * Added /proc/sys/net/core directory entry (empty =) ). [MS]
   6  */
   7
   8 #include <linux/mm.h>
   9 #include <linux/sysctl.h>
  10 #include <linux/module.h>
  11 #include <linux/socket.h>
  12 #include <linux/netdevice.h>
  13 #include <linux/ratelimit.h>
  14 #include <linux/vmalloc.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <linux/kmemleak.h>
  18
  19 #include <net/ip.h>
  20 #include <net/sock.h>
  21 #include <net/net_ratelimit.h>
  22 #include <net/busy_poll.h>
  23 #include <net/pkt_sched.h>
  24
  25 static int zero = 0;
  26 static int one = 1;
  27 static int min_sndbuf = SOCK_MIN_SNDBUF;
  28 static int min_rcvbuf = SOCK_MIN_RCVBUF;
  29 static int max_skb_frags = MAX_SKB_FRAGS;
  30
  31 static int net_msg_warn;        /* Unused, but still a sysctl */
  32
  33 #ifdef CONFIG_RPS
  34 static int rps_sock_flow_sysctl(struct ctl_table *table, int write,
  35                                 void __user *buffer, size_t *lenp, loff_t *ppos)
  36 {
  37         unsigned int orig_size, size;
  38         int ret, i;
  39         struct ctl_table tmp = {
  40                 .data = &size,
  41                 .maxlen = sizeof(size),
  42                 .mode = table->mode
  43         };
  44         struct rps_sock_flow_table *orig_sock_table, *sock_table;
  45         static DEFINE_MUTEX(sock_flow_mutex);
  46
  47         mutex_lock(&sock_flow_mutex);
  48
  49         orig_sock_table = rcu_dereference_protected(rps_sock_flow_table,
  50                                         lockdep_is_held(&sock_flow_mutex));
  51         size = orig_size = orig_sock_table ? orig_sock_table->mask + 1 : 0;
  52
  53         ret = proc_dointvec(&tmp, write, buffer, lenp, ppos);
  54
  55         if (write) {
  56                 if (size) {
  57                         if (size > 1<<29) {
  58                                 /* Enforce limit to prevent overflow */
  59                                 mutex_unlock(&sock_flow_mutex);
  60                                 return -EINVAL;
  61                         }
  62                         size = roundup_pow_of_two(size);
  63                         if (size != orig_size) {
  64                                 sock_table =
  65                                     vmalloc(RPS_SOCK_FLOW_TABLE_SIZE(size));
  66                                 if (!sock_table) {
  67                                         mutex_unlock(&sock_flow_mutex);
  68                                         return -ENOMEM;
  69                                 }
  70                                 rps_cpu_mask = roundup_pow_of_two(nr_cpu_ids) - 1;
  71                                 sock_table->mask = size - 1;
  72                         } else
  73                                 sock_table = orig_sock_table;
  74
  75                         for (i = 0; i < size; i++)
  76                                 sock_table->ents[i] = RPS_NO_CPU;
  77                 } else
  78                         sock_table = NULL;
  79
  80                 if (sock_table != orig_sock_table) {
  81                         rcu_assign_pointer(rps_sock_flow_table, sock_table);
  82                         if (sock_table) {
  83                                 static_key_slow_inc(&rps_needed);
  84                                 static_key_slow_inc(&rfs_needed);
  85                         }
  86                         if (orig_sock_table) {
  87                                 static_key_slow_dec(&rps_needed);
  88                                 static_key_slow_dec(&rfs_needed);
  89                                 synchronize_rcu();
  90                                 vfree(orig_sock_table);
  91                         }
  92                 }
  93         }
  94
  95         mutex_unlock(&sock_flow_mutex);
  96
  97         return ret;
  98 }
  99 #endif /* CONFIG_RPS */
 100
 101 #ifdef CONFIG_NET_FLOW_LIMIT
 102 static DEFINE_MUTEX(flow_limit_update_mutex);
 103
 104 static int flow_limit_cpu_sysctl(struct ctl_table *table, int write,
 105                                  void __user *buffer, size_t *lenp,
 106                                  loff_t *ppos)
 107 {
 108         struct sd_flow_limit *cur;
 109         struct softnet_data *sd;
 110         cpumask_var_t mask;
 111         int i, len, ret = 0;
 112
 113         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
 114                 return -ENOMEM;
 115
 116         if (write) {
 117                 ret = cpumask_parse_user(buffer, *lenp, mask);
 118                 if (ret)
 119                         goto done;
 120
 121                 mutex_lock(&flow_limit_update_mutex);
 122                 len = sizeof(*cur) + netdev_flow_limit_table_len;
 123                 for_each_possible_cpu(i) {
 124                         sd = &per_cpu(softnet_data, i);
 125                         cur = rcu_dereference_protected(sd->flow_limit,
 126                                      lockdep_is_held(&flow_limit_update_mutex));
 127                         if (cur && !cpumask_test_cpu(i, mask)) {
 128                                 RCU_INIT_POINTER(sd->flow_limit, NULL);
 129                                 synchronize_rcu();
 130                                 kfree(cur);
 131                         } else if (!cur && cpumask_test_cpu(i, mask)) {
 132                                 cur = kzalloc_node(len, GFP_KERNEL,
 133                                                    cpu_to_node(i));
 134                                 if (!cur) {
 135                                         /* not unwinding previous changes */
 136                                         ret = -ENOMEM;
 137                                         goto write_unlock;
 138                                 }
 139                                 cur->num_buckets = netdev_flow_limit_table_len;
 140                                 rcu_assign_pointer(sd->flow_limit, cur);
 141                         }
 142                 }
 143 write_unlock:
 144                 mutex_unlock(&flow_limit_update_mutex);
 145         } else {
 146                 char kbuf[128];
 147
 148                 if (*ppos || !*lenp) {
 149                         *lenp = 0;
 150                         goto done;
 151                 }
 152
 153                 cpumask_clear(mask);
 154                 rcu_read_lock();
 155                 for_each_possible_cpu(i) {
 156                         sd = &per_cpu(softnet_data, i);
 157                         if (rcu_dereference(sd->flow_limit))
 158                                 cpumask_set_cpu(i, mask);
 159                 }
 160                 rcu_read_unlock();
 161
 162                 len = min(sizeof(kbuf) - 1, *lenp);
 163                 len = scnprintf(kbuf, len, "%*pb", cpumask_pr_args(mask));
 164                 if (!len) {
 165                         *lenp = 0;
 166                         goto done;
 167                 }
 168                 if (len < *lenp)
 169                         kbuf[len++] = '\n';
 170                 if (copy_to_user(buffer, kbuf, len)) {
 171                         ret = -EFAULT;
 172                         goto done;
 173                 }
 174                 *lenp = len;
 175                 *ppos += len;
 176         }
 177
 178 done:
 179         free_cpumask_var(mask);
 180         return ret;
 181 }
 182
 183 static int flow_limit_table_len_sysctl(struct ctl_table *table, int write,
 184                                        void __user *buffer, size_t *lenp,
 185                                        loff_t *ppos)
 186 {
 187         unsigned int old, *ptr;
 188         int ret;
 189
 190         mutex_lock(&flow_limit_update_mutex);
 191
 192         ptr = table->data;
 193         old = *ptr;
 194         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 195         if (!ret && write && !is_power_of_2(*ptr)) {
 196                 *ptr = old;
 197                 ret = -EINVAL;
 198         }
 199
 200         mutex_unlock(&flow_limit_update_mutex);
 201         return ret;
 202 }
 203 #endif /* CONFIG_NET_FLOW_LIMIT */
 204
 205 #ifdef CONFIG_NET_SCHED
 206 static int set_default_qdisc(struct ctl_table *table, int write,
 207                              void __user *buffer, size_t *lenp, loff_t *ppos)
 208 {
 209         char id[IFNAMSIZ];
 210         struct ctl_table tbl = {
 211                 .data = id,
 212                 .maxlen = IFNAMSIZ,
 213         };
 214         int ret;
 215
 216         qdisc_get_default(id, IFNAMSIZ);
 217
 218         ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
 219         if (write && ret == 0)
 220                 ret = qdisc_set_default(id);
 221         return ret;
 222 }
 223 #endif
 224
 225 static int proc_do_rss_key(struct ctl_table *table, int write,
 226                            void __user *buffer, size_t *lenp, loff_t *ppos)
 227 {
 228         struct ctl_table fake_table;
 229         char buf[NETDEV_RSS_KEY_LEN * 3];
 230
 231         snprintf(buf, sizeof(buf), "%*phC", NETDEV_RSS_KEY_LEN, netdev_rss_key);
 232         fake_table.data = buf;
 233         fake_table.maxlen = sizeof(buf);
 234         return proc_dostring(&fake_table, write, buffer, lenp, ppos);
 235 }
 236
 237 static struct ctl_table net_core_table[] = {
 238 #ifdef CONFIG_NET
 239         {
 240                 .procname       = "wmem_max",
 241                 .data           = &sysctl_wmem_max,
 242                 .maxlen         = sizeof(int),
 243                 .mode           = 0644,
 244                 .proc_handler   = proc_dointvec_minmax,
 245                 .extra1         = &min_sndbuf,
 246         },
 247         {
 248                 .procname       = "rmem_max",
 249                 .data           = &sysctl_rmem_max,
 250                 .maxlen         = sizeof(int),
 251                 .mode           = 0644,
 252                 .proc_handler   = proc_dointvec_minmax,
 253                 .extra1         = &min_rcvbuf,
 254         },
 255         {
 256                 .procname       = "wmem_default",
 257                 .data           = &sysctl_wmem_default,
 258                 .maxlen         = sizeof(int),
 259                 .mode           = 0644,
 260                 .proc_handler   = proc_dointvec_minmax,
 261                 .extra1         = &min_sndbuf,
 262         },
 263         {
 264                 .procname       = "rmem_default",
 265                 .data           = &sysctl_rmem_default,
 266                 .maxlen         = sizeof(int),
 267                 .mode           = 0644,
 268                 .proc_handler   = proc_dointvec_minmax,
 269                 .extra1         = &min_rcvbuf,
 270         },
 271         {
 272                 .procname       = "dev_weight",
 273                 .data           = &weight_p,
 274                 .maxlen         = sizeof(int),
 275                 .mode           = 0644,
 276                 .proc_handler   = proc_dointvec
 277         },
 278         {
 279                 .procname       = "netdev_max_backlog",
 280                 .data           = &netdev_max_backlog,
 281                 .maxlen         = sizeof(int),
 282                 .mode           = 0644,
 283                 .proc_handler   = proc_dointvec
 284         },
 285         {
 286                 .procname       = "netdev_rss_key",
 287                 .data           = &netdev_rss_key,
 288                 .maxlen         = sizeof(int),
 289                 .mode           = 0444,
 290                 .proc_handler   = proc_do_rss_key,
 291         },
 292 #ifdef CONFIG_BPF_JIT
 293         {
 294                 .procname       = "bpf_jit_enable",
 295                 .data           = &bpf_jit_enable,
 296                 .maxlen         = sizeof(int),
 297                 .mode           = 0644,
 298                 .proc_handler   = proc_dointvec
 299         },
 300 # ifdef CONFIG_HAVE_EBPF_JIT
 301         {
 302                 .procname       = "bpf_jit_harden",
 303                 .data           = &bpf_jit_harden,
 304                 .maxlen         = sizeof(int),
 305                 .mode           = 0600,
 306                 .proc_handler   = proc_dointvec,
 307         },
 308 # endif
 309 #endif
 310         {
 311                 .procname       = "netdev_tstamp_prequeue",
 312                 .data           = &netdev_tstamp_prequeue,
 313                 .maxlen         = sizeof(int),
 314                 .mode           = 0644,
 315                 .proc_handler   = proc_dointvec
 316         },
 317         {
 318                 .procname       = "message_cost",
 319                 .data           = &net_ratelimit_state.interval,
 320                 .maxlen         = sizeof(int),
 321                 .mode           = 0644,
 322                 .proc_handler   = proc_dointvec_jiffies,
 323         },
 324         {
 325                 .procname       = "message_burst",
 326                 .data           = &net_ratelimit_state.burst,
 327                 .maxlen         = sizeof(int),
 328                 .mode           = 0644,
 329                 .proc_handler   = proc_dointvec,
 330         },
 331         {
 332                 .procname       = "optmem_max",
 333                 .data           = &sysctl_optmem_max,
 334                 .maxlen         = sizeof(int),
 335                 .mode           = 0644,
 336                 .proc_handler   = proc_dointvec
 337         },
 338         {
 339                 .procname       = "tstamp_allow_data",
 340                 .data           = &sysctl_tstamp_allow_data,
 341                 .maxlen         = sizeof(int),
 342                 .mode           = 0644,
 343                 .proc_handler   = proc_dointvec_minmax,
 344                 .extra1         = &zero,
 345                 .extra2         = &one
 346         },
 347 #ifdef CONFIG_RPS
 348         {
 349                 .procname       = "rps_sock_flow_entries",
 350                 .maxlen         = sizeof(int),
 351                 .mode           = 0644,
 352                 .proc_handler   = rps_sock_flow_sysctl
 353         },
 354 #endif
 355 #ifdef CONFIG_NET_FLOW_LIMIT
 356         {
 357                 .procname       = "flow_limit_cpu_bitmap",
 358                 .mode           = 0644,
 359                 .proc_handler   = flow_limit_cpu_sysctl
 360         },
 361         {
 362                 .procname       = "flow_limit_table_len",
 363                 .data           = &netdev_flow_limit_table_len,
 364                 .maxlen         = sizeof(int),
 365                 .mode           = 0644,
 366                 .proc_handler   = flow_limit_table_len_sysctl
 367         },
 368 #endif /* CONFIG_NET_FLOW_LIMIT */
 369 #ifdef CONFIG_NET_RX_BUSY_POLL
 370         {
 371                 .procname       = "busy_poll",
 372                 .data           = &sysctl_net_busy_poll,
 373                 .maxlen         = sizeof(unsigned int),
 374                 .mode           = 0644,
 375                 .proc_handler   = proc_dointvec
 376         },
 377         {
 378                 .procname       = "busy_read",
 379                 .data           = &sysctl_net_busy_read,
 380                 .maxlen         = sizeof(unsigned int),
 381                 .mode           = 0644,
 382                 .proc_handler   = proc_dointvec
 383         },
 384 #endif
 385 #ifdef CONFIG_NET_SCHED
 386         {
 387                 .procname       = "default_qdisc",
 388                 .mode           = 0644,
 389                 .maxlen         = IFNAMSIZ,
 390                 .proc_handler   = set_default_qdisc
 391         },
 392 #endif
 393 #endif /* CONFIG_NET */
 394         {
 395                 .procname       = "netdev_budget",
 396                 .data           = &netdev_budget,
 397                 .maxlen         = sizeof(int),
 398                 .mode           = 0644,
 399                 .proc_handler   = proc_dointvec
 400         },
 401         {
 402                 .procname       = "warnings",
 403                 .data           = &net_msg_warn,
 404                 .maxlen         = sizeof(int),
 405                 .mode           = 0644,
 406                 .proc_handler   = proc_dointvec
 407         },
 408         {
 409                 .procname       = "max_skb_frags",
 410                 .data           = &sysctl_max_skb_frags,
 411                 .maxlen         = sizeof(int),
 412                 .mode           = 0644,
 413                 .proc_handler   = proc_dointvec_minmax,
 414                 .extra1         = &one,
 415                 .extra2         = &max_skb_frags,
 416         },
 417         { }
 418 };
 419
 420 static struct ctl_table netns_core_table[] = {
 421         {
 422                 .procname       = "somaxconn",
 423                 .data           = &init_net.core.sysctl_somaxconn,
 424                 .maxlen         = sizeof(int),
 425                 .mode           = 0644,
 426                 .extra1         = &zero,
 427                 .proc_handler   = proc_dointvec_minmax
 428         },
 429         { }
 430 };
 431
 432 static __net_init int sysctl_core_net_init(struct net *net)
 433 {
 434         struct ctl_table *tbl;
 435
 436         net->core.sysctl_somaxconn = SOMAXCONN;
 437
 438         tbl = netns_core_table;
 439         if (!net_eq(net, &init_net)) {
 440                 tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);
 441                 if (tbl == NULL)
 442                         goto err_dup;
 443
 444                 tbl[0].data = &net->core.sysctl_somaxconn;
 445
 446                 /* Don't export any sysctls to unprivileged users */
 447                 if (net->user_ns != &init_user_ns) {
 448                         tbl[0].procname = NULL;
 449                 }
 450         }
 451
 452         net->core.sysctl_hdr = register_net_sysctl(net, "net/core", tbl);
 453         if (net->core.sysctl_hdr == NULL)
 454                 goto err_reg;
 455
 456         return 0;
 457
 458 err_reg:
 459         if (tbl != netns_core_table)
 460                 kfree(tbl);
 461 err_dup:
 462         return -ENOMEM;
 463 }
 464
 465 static __net_exit void sysctl_core_net_exit(struct net *net)
 466 {
 467         struct ctl_table *tbl;
 468
 469         tbl = net->core.sysctl_hdr->ctl_table_arg;
 470         unregister_net_sysctl_table(net->core.sysctl_hdr);
 471         BUG_ON(tbl == netns_core_table);
 472         kfree(tbl);
 473 }
 474
 475 static __net_initdata struct pernet_operations sysctl_core_ops = {
 476         .init = sysctl_core_net_init,
 477         .exit = sysctl_core_net_exit,
 478 };
 479
 480 static __init int sysctl_core_init(void)
 481 {
 482         register_net_sysctl(&init_net, "net/core", net_core_table);
 483         return register_pernet_subsys(&sysctl_core_ops);
 484 }
 485
 486 fs_initcall(sysctl_core_init);