net/core/sock_map.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */
   3
   4 #include <linux/bpf.h>
   5 #include <linux/filter.h>
   6 #include <linux/errno.h>
   7 #include <linux/file.h>
   8 #include <linux/net.h>
   9 #include <linux/workqueue.h>
  10 #include <linux/skmsg.h>
  11 #include <linux/list.h>
  12 #include <linux/jhash.h>
  13
  14 struct bpf_stab {
  15         struct bpf_map map;
  16         struct sock **sks;
  17         struct sk_psock_progs progs;
  18         raw_spinlock_t lock;
  19 };
  20
  21 #define SOCK_CREATE_FLAG_MASK                           \
  22         (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
  23
  24 static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
  25 {
  26         struct bpf_stab *stab;
  27         u64 cost;
  28         int err;
  29
  30         if (!capable(CAP_NET_ADMIN))
  31                 return ERR_PTR(-EPERM);
  32         if (attr->max_entries == 0 ||
  33             attr->key_size    != 4 ||
  34             attr->value_size  != 4 ||
  35             attr->map_flags & ~SOCK_CREATE_FLAG_MASK)
  36                 return ERR_PTR(-EINVAL);
  37
  38         stab = kzalloc(sizeof(*stab), GFP_USER);
  39         if (!stab)
  40                 return ERR_PTR(-ENOMEM);
  41
  42         bpf_map_init_from_attr(&stab->map, attr);
  43         raw_spin_lock_init(&stab->lock);
  44
  45         /* Make sure page count doesn't overflow. */
  46         cost = (u64) stab->map.max_entries * sizeof(struct sock *);
  47         if (cost >= U32_MAX - PAGE_SIZE) {
  48                 err = -EINVAL;
  49                 goto free_stab;
  50         }
  51
  52         stab->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
  53         err = bpf_map_precharge_memlock(stab->map.pages);
  54         if (err)
  55                 goto free_stab;
  56
  57         stab->sks = bpf_map_area_alloc(stab->map.max_entries *
  58                                        sizeof(struct sock *),
  59                                        stab->map.numa_node);
  60         if (stab->sks)
  61                 return &stab->map;
  62         err = -ENOMEM;
  63 free_stab:
  64         kfree(stab);
  65         return ERR_PTR(err);
  66 }
  67
  68 int sock_map_get_from_fd(const union bpf_attr *attr, struct bpf_prog *prog)
  69 {
  70         u32 ufd = attr->target_fd;
  71         struct bpf_map *map;
  72         struct fd f;
  73         int ret;
  74
  75         f = fdget(ufd);
  76         map = __bpf_map_get(f);
  77         if (IS_ERR(map))
  78                 return PTR_ERR(map);
  79         ret = sock_map_prog_update(map, prog, attr->attach_type);
  80         fdput(f);
  81         return ret;
  82 }
  83
  84 static void sock_map_sk_acquire(struct sock *sk)
  85         __acquires(&sk->sk_lock.slock)
  86 {
  87         lock_sock(sk);
  88         preempt_disable();
  89         rcu_read_lock();
  90 }
  91
  92 static void sock_map_sk_release(struct sock *sk)
  93         __releases(&sk->sk_lock.slock)
  94 {
  95         rcu_read_unlock();
  96         preempt_enable();
  97         release_sock(sk);
  98 }
  99
 100 static void sock_map_add_link(struct sk_psock *psock,
 101                               struct sk_psock_link *link,
 102                               struct bpf_map *map, void *link_raw)
 103 {
 104         link->link_raw = link_raw;
 105         link->map = map;
 106         spin_lock_bh(&psock->link_lock);
 107         list_add_tail(&link->list, &psock->link);
 108         spin_unlock_bh(&psock->link_lock);
 109 }
 110
 111 static void sock_map_del_link(struct sock *sk,
 112                               struct sk_psock *psock, void *link_raw)
 113 {
 114         struct sk_psock_link *link, *tmp;
 115         bool strp_stop = false;
 116
 117         spin_lock_bh(&psock->link_lock);
 118         list_for_each_entry_safe(link, tmp, &psock->link, list) {
 119                 if (link->link_raw == link_raw) {
 120                         struct bpf_map *map = link->map;
 121                         struct bpf_stab *stab = container_of(map, struct bpf_stab,
 122                                                              map);
 123                         if (psock->parser.enabled && stab->progs.skb_parser)
 124                                 strp_stop = true;
 125                         list_del(&link->list);
 126                         sk_psock_free_link(link);
 127                 }
 128         }
 129         spin_unlock_bh(&psock->link_lock);
 130         if (strp_stop) {
 131                 write_lock_bh(&sk->sk_callback_lock);
 132                 sk_psock_stop_strp(sk, psock);
 133                 write_unlock_bh(&sk->sk_callback_lock);
 134         }
 135 }
 136
 137 static void sock_map_unref(struct sock *sk, void *link_raw)
 138 {
 139         struct sk_psock *psock = sk_psock(sk);
 140
 141         if (likely(psock)) {
 142                 sock_map_del_link(sk, psock, link_raw);
 143                 sk_psock_put(sk, psock);
 144         }
 145 }
 146
 147 static int sock_map_link(struct bpf_map *map, struct sk_psock_progs *progs,
 148                          struct sock *sk)
 149 {
 150         struct bpf_prog *msg_parser, *skb_parser, *skb_verdict;
 151         bool skb_progs, sk_psock_is_new = false;
 152         struct sk_psock *psock;
 153         int ret;
 154
 155         skb_verdict = READ_ONCE(progs->skb_verdict);
 156         skb_parser = READ_ONCE(progs->skb_parser);
 157         skb_progs = skb_parser && skb_verdict;
 158         if (skb_progs) {
 159                 skb_verdict = bpf_prog_inc_not_zero(skb_verdict);
 160                 if (IS_ERR(skb_verdict))
 161                         return PTR_ERR(skb_verdict);
 162                 skb_parser = bpf_prog_inc_not_zero(skb_parser);
 163                 if (IS_ERR(skb_parser)) {
 164                         bpf_prog_put(skb_verdict);
 165                         return PTR_ERR(skb_parser);
 166                 }
 167         }
 168
 169         msg_parser = READ_ONCE(progs->msg_parser);
 170         if (msg_parser) {
 171                 msg_parser = bpf_prog_inc_not_zero(msg_parser);
 172                 if (IS_ERR(msg_parser)) {
 173                         ret = PTR_ERR(msg_parser);
 174                         goto out;
 175                 }
 176         }
 177
 178         psock = sk_psock_get_checked(sk);
 179         if (IS_ERR(psock)) {
 180                 ret = PTR_ERR(psock);
 181                 goto out_progs;
 182         }
 183
 184         if (psock) {
 185                 if ((msg_parser && READ_ONCE(psock->progs.msg_parser)) ||
 186                     (skb_progs  && READ_ONCE(psock->progs.skb_parser))) {
 187                         sk_psock_put(sk, psock);
 188                         ret = -EBUSY;
 189                         goto out_progs;
 190                 }
 191         } else {
 192                 psock = sk_psock_init(sk, map->numa_node);
 193                 if (!psock) {
 194                         ret = -ENOMEM;
 195                         goto out_progs;
 196                 }
 197                 sk_psock_is_new = true;
 198         }
 199
 200         if (msg_parser)
 201                 psock_set_prog(&psock->progs.msg_parser, msg_parser);
 202         if (sk_psock_is_new) {
 203                 ret = tcp_bpf_init(sk);
 204                 if (ret < 0)
 205                         goto out_drop;
 206         } else {
 207                 tcp_bpf_reinit(sk);
 208         }
 209
 210         write_lock_bh(&sk->sk_callback_lock);
 211         if (skb_progs && !psock->parser.enabled) {
 212                 ret = sk_psock_init_strp(sk, psock);
 213                 if (ret) {
 214                         write_unlock_bh(&sk->sk_callback_lock);
 215                         goto out_drop;
 216                 }
 217                 psock_set_prog(&psock->progs.skb_verdict, skb_verdict);
 218                 psock_set_prog(&psock->progs.skb_parser, skb_parser);
 219                 sk_psock_start_strp(sk, psock);
 220         }
 221         write_unlock_bh(&sk->sk_callback_lock);
 222         return 0;
 223 out_drop:
 224         sk_psock_put(sk, psock);
 225 out_progs:
 226         if (msg_parser)
 227                 bpf_prog_put(msg_parser);
 228 out:
 229         if (skb_progs) {
 230                 bpf_prog_put(skb_verdict);
 231                 bpf_prog_put(skb_parser);
 232         }
 233         return ret;
 234 }
 235
 236 static void sock_map_free(struct bpf_map *map)
 237 {
 238         struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
 239         int i;
 240
 241         synchronize_rcu();
 242         rcu_read_lock();
 243         raw_spin_lock_bh(&stab->lock);
 244         for (i = 0; i < stab->map.max_entries; i++) {
 245                 struct sock **psk = &stab->sks[i];
 246                 struct sock *sk;
 247
 248                 sk = xchg(psk, NULL);
 249                 if (sk)
 250                         sock_map_unref(sk, psk);
 251         }
 252         raw_spin_unlock_bh(&stab->lock);
 253         rcu_read_unlock();
 254
 255         bpf_map_area_free(stab->sks);
 256         kfree(stab);
 257 }
 258
 259 static void sock_map_release_progs(struct bpf_map *map)
 260 {
 261         psock_progs_drop(&container_of(map, struct bpf_stab, map)->progs);
 262 }
 263
 264 static struct sock *__sock_map_lookup_elem(struct bpf_map *map, u32 key)
 265 {
 266         struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
 267
 268         WARN_ON_ONCE(!rcu_read_lock_held());
 269
 270         if (unlikely(key >= map->max_entries))
 271                 return NULL;
 272         return READ_ONCE(stab->sks[key]);
 273 }
 274
 275 static void *sock_map_lookup(struct bpf_map *map, void *key)
 276 {
 277         return ERR_PTR(-EOPNOTSUPP);
 278 }
 279
 280 static int __sock_map_delete(struct bpf_stab *stab, struct sock *sk_test,
 281                              struct sock **psk)
 282 {
 283         struct sock *sk;
 284
 285         raw_spin_lock_bh(&stab->lock);
 286         sk = *psk;
 287         if (!sk_test || sk_test == sk)
 288                 *psk = NULL;
 289         raw_spin_unlock_bh(&stab->lock);
 290         if (unlikely(!sk))
 291                 return -EINVAL;
 292         sock_map_unref(sk, psk);
 293         return 0;
 294 }
 295
 296 static void sock_map_delete_from_link(struct bpf_map *map, struct sock *sk,
 297                                       void *link_raw)
 298 {
 299         struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
 300
 301         __sock_map_delete(stab, sk, link_raw);
 302 }
 303
 304 static int sock_map_delete_elem(struct bpf_map *map, void *key)
 305 {
 306         struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
 307         u32 i = *(u32 *)key;
 308         struct sock **psk;
 309
 310         if (unlikely(i >= map->max_entries))
 311                 return -EINVAL;
 312
 313         psk = &stab->sks[i];
 314         return __sock_map_delete(stab, NULL, psk);
 315 }
 316
 317 static int sock_map_get_next_key(struct bpf_map *map, void *key, void *next)
 318 {
 319         struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
 320         u32 i = key ? *(u32 *)key : U32_MAX;
 321         u32 *key_next = next;
 322
 323         if (i == stab->map.max_entries - 1)
 324                 return -ENOENT;
 325         if (i >= stab->map.max_entries)
 326                 *key_next = 0;
 327         else
 328                 *key_next = i + 1;
 329         return 0;
 330 }
 331
 332 static int sock_map_update_common(struct bpf_map *map, u32 idx,
 333                                   struct sock *sk, u64 flags)
 334 {
 335         struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
 336         struct sk_psock_link *link;
 337         struct sk_psock *psock;
 338         struct sock *osk;
 339         int ret;
 340
 341         WARN_ON_ONCE(!rcu_read_lock_held());
 342         if (unlikely(flags > BPF_EXIST))
 343                 return -EINVAL;
 344         if (unlikely(idx >= map->max_entries))
 345                 return -E2BIG;
 346
 347         link = sk_psock_init_link();
 348         if (!link)
 349                 return -ENOMEM;
 350
 351         ret = sock_map_link(map, &stab->progs, sk);
 352         if (ret < 0)
 353                 goto out_free;
 354
 355         psock = sk_psock(sk);
 356         WARN_ON_ONCE(!psock);
 357
 358         raw_spin_lock_bh(&stab->lock);
 359         osk = stab->sks[idx];
 360         if (osk && flags == BPF_NOEXIST) {
 361                 ret = -EEXIST;
 362                 goto out_unlock;
 363         } else if (!osk && flags == BPF_EXIST) {
 364                 ret = -ENOENT;
 365                 goto out_unlock;
 366         }
 367
 368         sock_map_add_link(psock, link, map, &stab->sks[idx]);
 369         stab->sks[idx] = sk;
 370         if (osk)
 371                 sock_map_unref(osk, &stab->sks[idx]);
 372         raw_spin_unlock_bh(&stab->lock);
 373         return 0;
 374 out_unlock:
 375         raw_spin_unlock_bh(&stab->lock);
 376         if (psock)
 377                 sk_psock_put(sk, psock);
 378 out_free:
 379         sk_psock_free_link(link);
 380         return ret;
 381 }
 382
 383 static bool sock_map_op_okay(const struct bpf_sock_ops_kern *ops)
 384 {
 385         return ops->op == BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB ||
 386                ops->op == BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB;
 387 }
 388
 389 static bool sock_map_sk_is_suitable(const struct sock *sk)
 390 {
 391         return sk->sk_type == SOCK_STREAM &&
 392                sk->sk_protocol == IPPROTO_TCP;
 393 }
 394
 395 static int sock_map_update_elem(struct bpf_map *map, void *key,
 396                                 void *value, u64 flags)
 397 {
 398         u32 ufd = *(u32 *)value;
 399         u32 idx = *(u32 *)key;
 400         struct socket *sock;
 401         struct sock *sk;
 402         int ret;
 403
 404         sock = sockfd_lookup(ufd, &ret);
 405         if (!sock)
 406                 return ret;
 407         sk = sock->sk;
 408         if (!sk) {
 409                 ret = -EINVAL;
 410                 goto out;
 411         }
 412         if (!sock_map_sk_is_suitable(sk) ||
 413             sk->sk_state != TCP_ESTABLISHED) {
 414                 ret = -EOPNOTSUPP;
 415                 goto out;
 416         }
 417
 418         sock_map_sk_acquire(sk);
 419         ret = sock_map_update_common(map, idx, sk, flags);
 420         sock_map_sk_release(sk);
 421 out:
 422         fput(sock->file);
 423         return ret;
 424 }
 425
 426 BPF_CALL_4(bpf_sock_map_update, struct bpf_sock_ops_kern *, sops,
 427            struct bpf_map *, map, void *, key, u64, flags)
 428 {
 429         WARN_ON_ONCE(!rcu_read_lock_held());
 430
 431         if (likely(sock_map_sk_is_suitable(sops->sk) &&
 432                    sock_map_op_okay(sops)))
 433                 return sock_map_update_common(map, *(u32 *)key, sops->sk,
 434                                               flags);
 435         return -EOPNOTSUPP;
 436 }
 437
 438 const struct bpf_func_proto bpf_sock_map_update_proto = {
 439         .func           = bpf_sock_map_update,
 440         .gpl_only       = false,
 441         .pkt_access     = true,
 442         .ret_type       = RET_INTEGER,
 443         .arg1_type      = ARG_PTR_TO_CTX,
 444         .arg2_type      = ARG_CONST_MAP_PTR,
 445         .arg3_type      = ARG_PTR_TO_MAP_KEY,
 446         .arg4_type      = ARG_ANYTHING,
 447 };
 448
 449 BPF_CALL_4(bpf_sk_redirect_map, struct sk_buff *, skb,
 450            struct bpf_map *, map, u32, key, u64, flags)
 451 {
 452         struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
 453
 454         if (unlikely(flags & ~(BPF_F_INGRESS)))
 455                 return SK_DROP;
 456         tcb->bpf.flags = flags;
 457         tcb->bpf.sk_redir = __sock_map_lookup_elem(map, key);
 458         if (!tcb->bpf.sk_redir)
 459                 return SK_DROP;
 460         return SK_PASS;
 461 }
 462
 463 const struct bpf_func_proto bpf_sk_redirect_map_proto = {
 464         .func           = bpf_sk_redirect_map,
 465         .gpl_only       = false,
 466         .ret_type       = RET_INTEGER,
 467         .arg1_type      = ARG_PTR_TO_CTX,
 468         .arg2_type      = ARG_CONST_MAP_PTR,
 469         .arg3_type      = ARG_ANYTHING,
 470         .arg4_type      = ARG_ANYTHING,
 471 };
 472
 473 BPF_CALL_4(bpf_msg_redirect_map, struct sk_msg *, msg,
 474            struct bpf_map *, map, u32, key, u64, flags)
 475 {
 476         if (unlikely(flags & ~(BPF_F_INGRESS)))
 477                 return SK_DROP;
 478         msg->flags = flags;
 479         msg->sk_redir = __sock_map_lookup_elem(map, key);
 480         if (!msg->sk_redir)
 481                 return SK_DROP;
 482         return SK_PASS;
 483 }
 484
 485 const struct bpf_func_proto bpf_msg_redirect_map_proto = {
 486         .func           = bpf_msg_redirect_map,
 487         .gpl_only       = false,
 488         .ret_type       = RET_INTEGER,
 489         .arg1_type      = ARG_PTR_TO_CTX,
 490         .arg2_type      = ARG_CONST_MAP_PTR,
 491         .arg3_type      = ARG_ANYTHING,
 492         .arg4_type      = ARG_ANYTHING,
 493 };
 494
 495 const struct bpf_map_ops sock_map_ops = {
 496         .map_alloc              = sock_map_alloc,
 497         .map_free               = sock_map_free,
 498         .map_get_next_key       = sock_map_get_next_key,
 499         .map_update_elem        = sock_map_update_elem,
 500         .map_delete_elem        = sock_map_delete_elem,
 501         .map_lookup_elem        = sock_map_lookup,
 502         .map_release_uref       = sock_map_release_progs,
 503         .map_check_btf          = map_check_no_btf,
 504 };
 505
 506 struct bpf_htab_elem {
 507         struct rcu_head rcu;
 508         u32 hash;
 509         struct sock *sk;
 510         struct hlist_node node;
 511         u8 key[0];
 512 };
 513
 514 struct bpf_htab_bucket {
 515         struct hlist_head head;
 516         raw_spinlock_t lock;
 517 };
 518
 519 struct bpf_htab {
 520         struct bpf_map map;
 521         struct bpf_htab_bucket *buckets;
 522         u32 buckets_num;
 523         u32 elem_size;
 524         struct sk_psock_progs progs;
 525         atomic_t count;
 526 };
 527
 528 static inline u32 sock_hash_bucket_hash(const void *key, u32 len)
 529 {
 530         return jhash(key, len, 0);
 531 }
 532
 533 static struct bpf_htab_bucket *sock_hash_select_bucket(struct bpf_htab *htab,
 534                                                        u32 hash)
 535 {
 536         return &htab->buckets[hash & (htab->buckets_num - 1)];
 537 }
 538
 539 static struct bpf_htab_elem *
 540 sock_hash_lookup_elem_raw(struct hlist_head *head, u32 hash, void *key,
 541                           u32 key_size)
 542 {
 543         struct bpf_htab_elem *elem;
 544
 545         hlist_for_each_entry_rcu(elem, head, node) {
 546                 if (elem->hash == hash &&
 547                     !memcmp(&elem->key, key, key_size))
 548                         return elem;
 549         }
 550
 551         return NULL;
 552 }
 553
 554 static struct sock *__sock_hash_lookup_elem(struct bpf_map *map, void *key)
 555 {
 556         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
 557         u32 key_size = map->key_size, hash;
 558         struct bpf_htab_bucket *bucket;
 559         struct bpf_htab_elem *elem;
 560
 561         WARN_ON_ONCE(!rcu_read_lock_held());
 562
 563         hash = sock_hash_bucket_hash(key, key_size);
 564         bucket = sock_hash_select_bucket(htab, hash);
 565         elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size);
 566
 567         return elem ? elem->sk : NULL;
 568 }
 569
 570 static void sock_hash_free_elem(struct bpf_htab *htab,
 571                                 struct bpf_htab_elem *elem)
 572 {
 573         atomic_dec(&htab->count);
 574         kfree_rcu(elem, rcu);
 575 }
 576
 577 static void sock_hash_delete_from_link(struct bpf_map *map, struct sock *sk,
 578                                        void *link_raw)
 579 {
 580         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
 581         struct bpf_htab_elem *elem_probe, *elem = link_raw;
 582         struct bpf_htab_bucket *bucket;
 583
 584         WARN_ON_ONCE(!rcu_read_lock_held());
 585         bucket = sock_hash_select_bucket(htab, elem->hash);
 586
 587         /* elem may be deleted in parallel from the map, but access here
 588          * is okay since it's going away only after RCU grace period.
 589          * However, we need to check whether it's still present.
 590          */
 591         raw_spin_lock_bh(&bucket->lock);
 592         elem_probe = sock_hash_lookup_elem_raw(&bucket->head, elem->hash,
 593                                                elem->key, map->key_size);
 594         if (elem_probe && elem_probe == elem) {
 595                 hlist_del_rcu(&elem->node);
 596                 sock_map_unref(elem->sk, elem);
 597                 sock_hash_free_elem(htab, elem);
 598         }
 599         raw_spin_unlock_bh(&bucket->lock);
 600 }
 601
 602 static int sock_hash_delete_elem(struct bpf_map *map, void *key)
 603 {
 604         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
 605         u32 hash, key_size = map->key_size;
 606         struct bpf_htab_bucket *bucket;
 607         struct bpf_htab_elem *elem;
 608         int ret = -ENOENT;
 609
 610         hash = sock_hash_bucket_hash(key, key_size);
 611         bucket = sock_hash_select_bucket(htab, hash);
 612
 613         raw_spin_lock_bh(&bucket->lock);
 614         elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size);
 615         if (elem) {
 616                 hlist_del_rcu(&elem->node);
 617                 sock_map_unref(elem->sk, elem);
 618                 sock_hash_free_elem(htab, elem);
 619                 ret = 0;
 620         }
 621         raw_spin_unlock_bh(&bucket->lock);
 622         return ret;
 623 }
 624
 625 static struct bpf_htab_elem *sock_hash_alloc_elem(struct bpf_htab *htab,
 626                                                   void *key, u32 key_size,
 627                                                   u32 hash, struct sock *sk,
 628                                                   struct bpf_htab_elem *old)
 629 {
 630         struct bpf_htab_elem *new;
 631
 632         if (atomic_inc_return(&htab->count) > htab->map.max_entries) {
 633                 if (!old) {
 634                         atomic_dec(&htab->count);
 635                         return ERR_PTR(-E2BIG);
 636                 }
 637         }
 638
 639         new = kmalloc_node(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN,
 640                            htab->map.numa_node);
 641         if (!new) {
 642                 atomic_dec(&htab->count);
 643                 return ERR_PTR(-ENOMEM);
 644         }
 645         memcpy(new->key, key, key_size);
 646         new->sk = sk;
 647         new->hash = hash;
 648         return new;
 649 }
 650
 651 static int sock_hash_update_common(struct bpf_map *map, void *key,
 652                                    struct sock *sk, u64 flags)
 653 {
 654         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
 655         u32 key_size = map->key_size, hash;
 656         struct bpf_htab_elem *elem, *elem_new;
 657         struct bpf_htab_bucket *bucket;
 658         struct sk_psock_link *link;
 659         struct sk_psock *psock;
 660         int ret;
 661
 662         WARN_ON_ONCE(!rcu_read_lock_held());
 663         if (unlikely(flags > BPF_EXIST))
 664                 return -EINVAL;
 665
 666         link = sk_psock_init_link();
 667         if (!link)
 668                 return -ENOMEM;
 669
 670         ret = sock_map_link(map, &htab->progs, sk);
 671         if (ret < 0)
 672                 goto out_free;
 673
 674         psock = sk_psock(sk);
 675         WARN_ON_ONCE(!psock);
 676
 677         hash = sock_hash_bucket_hash(key, key_size);
 678         bucket = sock_hash_select_bucket(htab, hash);
 679
 680         raw_spin_lock_bh(&bucket->lock);
 681         elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size);
 682         if (elem && flags == BPF_NOEXIST) {
 683                 ret = -EEXIST;
 684                 goto out_unlock;
 685         } else if (!elem && flags == BPF_EXIST) {
 686                 ret = -ENOENT;
 687                 goto out_unlock;
 688         }
 689
 690         elem_new = sock_hash_alloc_elem(htab, key, key_size, hash, sk, elem);
 691         if (IS_ERR(elem_new)) {
 692                 ret = PTR_ERR(elem_new);
 693                 goto out_unlock;
 694         }
 695
 696         sock_map_add_link(psock, link, map, elem_new);
 697         /* Add new element to the head of the list, so that
 698          * concurrent search will find it before old elem.
 699          */
 700         hlist_add_head_rcu(&elem_new->node, &bucket->head);
 701         if (elem) {
 702                 hlist_del_rcu(&elem->node);
 703                 sock_map_unref(elem->sk, elem);
 704                 sock_hash_free_elem(htab, elem);
 705         }
 706         raw_spin_unlock_bh(&bucket->lock);
 707         return 0;
 708 out_unlock:
 709         raw_spin_unlock_bh(&bucket->lock);
 710         sk_psock_put(sk, psock);
 711 out_free:
 712         sk_psock_free_link(link);
 713         return ret;
 714 }
 715
 716 static int sock_hash_update_elem(struct bpf_map *map, void *key,
 717                                  void *value, u64 flags)
 718 {
 719         u32 ufd = *(u32 *)value;
 720         struct socket *sock;
 721         struct sock *sk;
 722         int ret;
 723
 724         sock = sockfd_lookup(ufd, &ret);
 725         if (!sock)
 726                 return ret;
 727         sk = sock->sk;
 728         if (!sk) {
 729                 ret = -EINVAL;
 730                 goto out;
 731         }
 732         if (!sock_map_sk_is_suitable(sk) ||
 733             sk->sk_state != TCP_ESTABLISHED) {
 734                 ret = -EOPNOTSUPP;
 735                 goto out;
 736         }
 737
 738         sock_map_sk_acquire(sk);
 739         ret = sock_hash_update_common(map, key, sk, flags);
 740         sock_map_sk_release(sk);
 741 out:
 742         fput(sock->file);
 743         return ret;
 744 }
 745
 746 static int sock_hash_get_next_key(struct bpf_map *map, void *key,
 747                                   void *key_next)
 748 {
 749         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
 750         struct bpf_htab_elem *elem, *elem_next;
 751         u32 hash, key_size = map->key_size;
 752         struct hlist_head *head;
 753         int i = 0;
 754
 755         if (!key)
 756                 goto find_first_elem;
 757         hash = sock_hash_bucket_hash(key, key_size);
 758         head = &sock_hash_select_bucket(htab, hash)->head;
 759         elem = sock_hash_lookup_elem_raw(head, hash, key, key_size);
 760         if (!elem)
 761                 goto find_first_elem;
 762
 763         elem_next = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&elem->node)),
 764                                      struct bpf_htab_elem, node);
 765         if (elem_next) {
 766                 memcpy(key_next, elem_next->key, key_size);
 767                 return 0;
 768         }
 769
 770         i = hash & (htab->buckets_num - 1);
 771         i++;
 772 find_first_elem:
 773         for (; i < htab->buckets_num; i++) {
 774                 head = &sock_hash_select_bucket(htab, i)->head;
 775                 elem_next = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),
 776                                              struct bpf_htab_elem, node);
 777                 if (elem_next) {
 778                         memcpy(key_next, elem_next->key, key_size);
 779                         return 0;
 780                 }
 781         }
 782
 783         return -ENOENT;
 784 }
 785
 786 static struct bpf_map *sock_hash_alloc(union bpf_attr *attr)
 787 {
 788         struct bpf_htab *htab;
 789         int i, err;
 790         u64 cost;
 791
 792         if (!capable(CAP_NET_ADMIN))
 793                 return ERR_PTR(-EPERM);
 794         if (attr->max_entries == 0 ||
 795             attr->key_size    == 0 ||
 796             attr->value_size  != 4 ||
 797             attr->map_flags & ~SOCK_CREATE_FLAG_MASK)
 798                 return ERR_PTR(-EINVAL);
 799         if (attr->key_size > MAX_BPF_STACK)
 800                 return ERR_PTR(-E2BIG);
 801
 802         htab = kzalloc(sizeof(*htab), GFP_USER);
 803         if (!htab)
 804                 return ERR_PTR(-ENOMEM);
 805
 806         bpf_map_init_from_attr(&htab->map, attr);
 807
 808         htab->buckets_num = roundup_pow_of_two(htab->map.max_entries);
 809         htab->elem_size = sizeof(struct bpf_htab_elem) +
 810                           round_up(htab->map.key_size, 8);
 811         if (htab->buckets_num == 0 ||
 812             htab->buckets_num > U32_MAX / sizeof(struct bpf_htab_bucket)) {
 813                 err = -EINVAL;
 814                 goto free_htab;
 815         }
 816
 817         cost = (u64) htab->buckets_num * sizeof(struct bpf_htab_bucket) +
 818                (u64) htab->elem_size * htab->map.max_entries;
 819         if (cost >= U32_MAX - PAGE_SIZE) {
 820                 err = -EINVAL;
 821                 goto free_htab;
 822         }
 823
 824         htab->buckets = bpf_map_area_alloc(htab->buckets_num *
 825                                            sizeof(struct bpf_htab_bucket),
 826                                            htab->map.numa_node);
 827         if (!htab->buckets) {
 828                 err = -ENOMEM;
 829                 goto free_htab;
 830         }
 831
 832         for (i = 0; i < htab->buckets_num; i++) {
 833                 INIT_HLIST_HEAD(&htab->buckets[i].head);
 834                 raw_spin_lock_init(&htab->buckets[i].lock);
 835         }
 836
 837         return &htab->map;
 838 free_htab:
 839         kfree(htab);
 840         return ERR_PTR(err);
 841 }
 842
 843 static void sock_hash_free(struct bpf_map *map)
 844 {
 845         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
 846         struct bpf_htab_bucket *bucket;
 847         struct bpf_htab_elem *elem;
 848         struct hlist_node *node;
 849         int i;
 850
 851         synchronize_rcu();
 852         rcu_read_lock();
 853         for (i = 0; i < htab->buckets_num; i++) {
 854                 bucket = sock_hash_select_bucket(htab, i);
 855                 raw_spin_lock_bh(&bucket->lock);
 856                 hlist_for_each_entry_safe(elem, node, &bucket->head, node) {
 857                         hlist_del_rcu(&elem->node);
 858                         sock_map_unref(elem->sk, elem);
 859                 }
 860                 raw_spin_unlock_bh(&bucket->lock);
 861         }
 862         rcu_read_unlock();
 863
 864         bpf_map_area_free(htab->buckets);
 865         kfree(htab);
 866 }
 867
 868 static void sock_hash_release_progs(struct bpf_map *map)
 869 {
 870         psock_progs_drop(&container_of(map, struct bpf_htab, map)->progs);
 871 }
 872
 873 BPF_CALL_4(bpf_sock_hash_update, struct bpf_sock_ops_kern *, sops,
 874            struct bpf_map *, map, void *, key, u64, flags)
 875 {
 876         WARN_ON_ONCE(!rcu_read_lock_held());
 877
 878         if (likely(sock_map_sk_is_suitable(sops->sk) &&
 879                    sock_map_op_okay(sops)))
 880                 return sock_hash_update_common(map, key, sops->sk, flags);
 881         return -EOPNOTSUPP;
 882 }
 883
 884 const struct bpf_func_proto bpf_sock_hash_update_proto = {
 885         .func           = bpf_sock_hash_update,
 886         .gpl_only       = false,
 887         .pkt_access     = true,
 888         .ret_type       = RET_INTEGER,
 889         .arg1_type      = ARG_PTR_TO_CTX,
 890         .arg2_type      = ARG_CONST_MAP_PTR,
 891         .arg3_type      = ARG_PTR_TO_MAP_KEY,
 892         .arg4_type      = ARG_ANYTHING,
 893 };
 894
 895 BPF_CALL_4(bpf_sk_redirect_hash, struct sk_buff *, skb,
 896            struct bpf_map *, map, void *, key, u64, flags)
 897 {
 898         struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
 899
 900         if (unlikely(flags & ~(BPF_F_INGRESS)))
 901                 return SK_DROP;
 902         tcb->bpf.flags = flags;
 903         tcb->bpf.sk_redir = __sock_hash_lookup_elem(map, key);
 904         if (!tcb->bpf.sk_redir)
 905                 return SK_DROP;
 906         return SK_PASS;
 907 }
 908
 909 const struct bpf_func_proto bpf_sk_redirect_hash_proto = {
 910         .func           = bpf_sk_redirect_hash,
 911         .gpl_only       = false,
 912         .ret_type       = RET_INTEGER,
 913         .arg1_type      = ARG_PTR_TO_CTX,
 914         .arg2_type      = ARG_CONST_MAP_PTR,
 915         .arg3_type      = ARG_PTR_TO_MAP_KEY,
 916         .arg4_type      = ARG_ANYTHING,
 917 };
 918
 919 BPF_CALL_4(bpf_msg_redirect_hash, struct sk_msg *, msg,
 920            struct bpf_map *, map, void *, key, u64, flags)
 921 {
 922         if (unlikely(flags & ~(BPF_F_INGRESS)))
 923                 return SK_DROP;
 924         msg->flags = flags;
 925         msg->sk_redir = __sock_hash_lookup_elem(map, key);
 926         if (!msg->sk_redir)
 927                 return SK_DROP;
 928         return SK_PASS;
 929 }
 930
 931 const struct bpf_func_proto bpf_msg_redirect_hash_proto = {
 932         .func           = bpf_msg_redirect_hash,
 933         .gpl_only       = false,
 934         .ret_type       = RET_INTEGER,
 935         .arg1_type      = ARG_PTR_TO_CTX,
 936         .arg2_type      = ARG_CONST_MAP_PTR,
 937         .arg3_type      = ARG_PTR_TO_MAP_KEY,
 938         .arg4_type      = ARG_ANYTHING,
 939 };
 940
 941 const struct bpf_map_ops sock_hash_ops = {
 942         .map_alloc              = sock_hash_alloc,
 943         .map_free               = sock_hash_free,
 944         .map_get_next_key       = sock_hash_get_next_key,
 945         .map_update_elem        = sock_hash_update_elem,
 946         .map_delete_elem        = sock_hash_delete_elem,
 947         .map_lookup_elem        = sock_map_lookup,
 948         .map_release_uref       = sock_hash_release_progs,
 949         .map_check_btf          = map_check_no_btf,
 950 };
 951
 952 static struct sk_psock_progs *sock_map_progs(struct bpf_map *map)
 953 {
 954         switch (map->map_type) {
 955         case BPF_MAP_TYPE_SOCKMAP:
 956                 return &container_of(map, struct bpf_stab, map)->progs;
 957         case BPF_MAP_TYPE_SOCKHASH:
 958                 return &container_of(map, struct bpf_htab, map)->progs;
 959         default:
 960                 break;
 961         }
 962
 963         return NULL;
 964 }
 965
 966 int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog,
 967                          u32 which)
 968 {
 969         struct sk_psock_progs *progs = sock_map_progs(map);
 970
 971         if (!progs)
 972                 return -EOPNOTSUPP;
 973
 974         switch (which) {
 975         case BPF_SK_MSG_VERDICT:
 976                 psock_set_prog(&progs->msg_parser, prog);
 977                 break;
 978         case BPF_SK_SKB_STREAM_PARSER:
 979                 psock_set_prog(&progs->skb_parser, prog);
 980                 break;
 981         case BPF_SK_SKB_STREAM_VERDICT:
 982                 psock_set_prog(&progs->skb_verdict, prog);
 983                 break;
 984         default:
 985                 return -EOPNOTSUPP;
 986         }
 987
 988         return 0;
 989 }
 990
 991 void sk_psock_unlink(struct sock *sk, struct sk_psock_link *link)
 992 {
 993         switch (link->map->map_type) {
 994         case BPF_MAP_TYPE_SOCKMAP:
 995                 return sock_map_delete_from_link(link->map, sk,
 996                                                  link->link_raw);
 997         case BPF_MAP_TYPE_SOCKHASH:
 998                 return sock_hash_delete_from_link(link->map, sk,
 999                                                   link->link_raw);
1000         default:
1001                 break;
1002         }
1003 }