include/linux/skmsg.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */
   3
   4 #ifndef _LINUX_SKMSG_H
   5 #define _LINUX_SKMSG_H
   6
   7 #include <linux/bpf.h>
   8 #include <linux/filter.h>
   9 #include <linux/scatterlist.h>
  10 #include <linux/skbuff.h>
  11
  12 #include <net/sock.h>
  13 #include <net/tcp.h>
  14 #include <net/strparser.h>
  15
  16 #define MAX_MSG_FRAGS                   MAX_SKB_FRAGS
  17 #define NR_MSG_FRAG_IDS                 (MAX_MSG_FRAGS + 1)
  18
  19 enum __sk_action {
  20         __SK_DROP = 0,
  21         __SK_PASS,
  22         __SK_REDIRECT,
  23         __SK_NONE,
  24 };
  25
  26 struct sk_msg_sg {
  27         u32                             start;
  28         u32                             curr;
  29         u32                             end;
  30         u32                             size;
  31         u32                             copybreak;
  32         DECLARE_BITMAP(copy, MAX_MSG_FRAGS + 2);
  33         /* The extra two elements:
  34          * 1) used for chaining the front and sections when the list becomes
  35          *    partitioned (e.g. end < start). The crypto APIs require the
  36          *    chaining;
  37          * 2) to chain tailer SG entries after the message.
  38          */
  39         struct scatterlist              data[MAX_MSG_FRAGS + 2];
  40 };
  41
  42 /* UAPI in filter.c depends on struct sk_msg_sg being first element. */
  43 struct sk_msg {
  44         struct sk_msg_sg                sg;
  45         void                            *data;
  46         void                            *data_end;
  47         u32                             apply_bytes;
  48         u32                             cork_bytes;
  49         u32                             flags;
  50         struct sk_buff                  *skb;
  51         struct sock                     *sk_redir;
  52         struct sock                     *sk;
  53         struct list_head                list;
  54 };
  55
  56 struct sk_psock_progs {
  57         struct bpf_prog                 *msg_parser;
  58         struct bpf_prog                 *stream_parser;
  59         struct bpf_prog                 *stream_verdict;
  60         struct bpf_prog                 *skb_verdict;
  61         struct bpf_link                 *msg_parser_link;
  62         struct bpf_link                 *stream_parser_link;
  63         struct bpf_link                 *stream_verdict_link;
  64         struct bpf_link                 *skb_verdict_link;
  65 };
  66
  67 enum sk_psock_state_bits {
  68         SK_PSOCK_TX_ENABLED,
  69         SK_PSOCK_RX_STRP_ENABLED,
  70 };
  71
  72 struct sk_psock_link {
  73         struct list_head                list;
  74         struct bpf_map                  *map;
  75         void                            *link_raw;
  76 };
  77
  78 struct sk_psock_work_state {
  79         u32                             len;
  80         u32                             off;
  81 };
  82
  83 struct sk_psock {
  84         struct sock                     *sk;
  85         struct sock                     *sk_redir;
  86         u32                             apply_bytes;
  87         u32                             cork_bytes;
  88         u32                             eval;
  89         bool                            redir_ingress; /* undefined if sk_redir is null */
  90         struct sk_msg                   *cork;
  91         struct sk_psock_progs           progs;
  92 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
  93         struct strparser                strp;
  94 #endif
  95         struct sk_buff_head             ingress_skb;
  96         struct list_head                ingress_msg;
  97         spinlock_t                      ingress_lock;
  98         unsigned long                   state;
  99         struct list_head                link;
 100         spinlock_t                      link_lock;
 101         refcount_t                      refcnt;
 102         void (*saved_unhash)(struct sock *sk);
 103         void (*saved_destroy)(struct sock *sk);
 104         void (*saved_close)(struct sock *sk, long timeout);
 105         void (*saved_write_space)(struct sock *sk);
 106         void (*saved_data_ready)(struct sock *sk);
 107         /* psock_update_sk_prot may be called with restore=false many times
 108          * so the handler must be safe for this case. It will be called
 109          * exactly once with restore=true when the psock is being destroyed
 110          * and psock refcnt is zero, but before an RCU grace period.
 111          */
 112         int  (*psock_update_sk_prot)(struct sock *sk, struct sk_psock *psock,
 113                                      bool restore);
 114         struct proto                    *sk_proto;
 115         struct mutex                    work_mutex;
 116         struct sk_psock_work_state      work_state;
 117         struct delayed_work             work;
 118         struct sock                     *sk_pair;
 119         struct rcu_work                 rwork;
 120 };
 121
 122 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
 123                  int elem_first_coalesce);
 124 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
 125                  u32 off, u32 len);
 126 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len);
 127 int sk_msg_free(struct sock *sk, struct sk_msg *msg);
 128 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg);
 129 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes);
 130 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
 131                                   u32 bytes);
 132
 133 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes);
 134 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes);
 135
 136 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
 137                               struct sk_msg *msg, u32 bytes);
 138 int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
 139                              struct sk_msg *msg, u32 bytes);
 140 int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
 141                    int len, int flags);
 142 bool sk_msg_is_readable(struct sock *sk);
 143
 144 static inline void sk_msg_check_to_free(struct sk_msg *msg, u32 i, u32 bytes)
 145 {
 146         WARN_ON(i == msg->sg.end && bytes);
 147 }
 148
 149 static inline void sk_msg_apply_bytes(struct sk_psock *psock, u32 bytes)
 150 {
 151         if (psock->apply_bytes) {
 152                 if (psock->apply_bytes < bytes)
 153                         psock->apply_bytes = 0;
 154                 else
 155                         psock->apply_bytes -= bytes;
 156         }
 157 }
 158
 159 static inline u32 sk_msg_iter_dist(u32 start, u32 end)
 160 {
 161         return end >= start ? end - start : end + (NR_MSG_FRAG_IDS - start);
 162 }
 163
 164 #define sk_msg_iter_var_prev(var)                       \
 165         do {                                            \
 166                 if (var == 0)                           \
 167                         var = NR_MSG_FRAG_IDS - 1;      \
 168                 else                                    \
 169                         var--;                          \
 170         } while (0)
 171
 172 #define sk_msg_iter_var_next(var)                       \
 173         do {                                            \
 174                 var++;                                  \
 175                 if (var == NR_MSG_FRAG_IDS)             \
 176                         var = 0;                        \
 177         } while (0)
 178
 179 #define sk_msg_iter_prev(msg, which)                    \
 180         sk_msg_iter_var_prev(msg->sg.which)
 181
 182 #define sk_msg_iter_next(msg, which)                    \
 183         sk_msg_iter_var_next(msg->sg.which)
 184
 185 static inline void sk_msg_init(struct sk_msg *msg)
 186 {
 187         BUILD_BUG_ON(ARRAY_SIZE(msg->sg.data) - 1 != NR_MSG_FRAG_IDS);
 188         memset(msg, 0, sizeof(*msg));
 189         sg_init_marker(msg->sg.data, NR_MSG_FRAG_IDS);
 190 }
 191
 192 static inline void sk_msg_xfer(struct sk_msg *dst, struct sk_msg *src,
 193                                int which, u32 size)
 194 {
 195         dst->sg.data[which] = src->sg.data[which];
 196         dst->sg.data[which].length  = size;
 197         dst->sg.size               += size;
 198         src->sg.size               -= size;
 199         src->sg.data[which].length -= size;
 200         src->sg.data[which].offset += size;
 201 }
 202
 203 static inline void sk_msg_xfer_full(struct sk_msg *dst, struct sk_msg *src)
 204 {
 205         memcpy(dst, src, sizeof(*src));
 206         sk_msg_init(src);
 207 }
 208
 209 static inline bool sk_msg_full(const struct sk_msg *msg)
 210 {
 211         return sk_msg_iter_dist(msg->sg.start, msg->sg.end) == MAX_MSG_FRAGS;
 212 }
 213
 214 static inline u32 sk_msg_elem_used(const struct sk_msg *msg)
 215 {
 216         return sk_msg_iter_dist(msg->sg.start, msg->sg.end);
 217 }
 218
 219 static inline struct scatterlist *sk_msg_elem(struct sk_msg *msg, int which)
 220 {
 221         return &msg->sg.data[which];
 222 }
 223
 224 static inline struct scatterlist sk_msg_elem_cpy(struct sk_msg *msg, int which)
 225 {
 226         return msg->sg.data[which];
 227 }
 228
 229 static inline struct page *sk_msg_page(struct sk_msg *msg, int which)
 230 {
 231         return sg_page(sk_msg_elem(msg, which));
 232 }
 233
 234 static inline bool sk_msg_to_ingress(const struct sk_msg *msg)
 235 {
 236         return msg->flags & BPF_F_INGRESS;
 237 }
 238
 239 static inline void sk_msg_compute_data_pointers(struct sk_msg *msg)
 240 {
 241         struct scatterlist *sge = sk_msg_elem(msg, msg->sg.start);
 242
 243         if (test_bit(msg->sg.start, msg->sg.copy)) {
 244                 msg->data = NULL;
 245                 msg->data_end = NULL;
 246         } else {
 247                 msg->data = sg_virt(sge);
 248                 msg->data_end = msg->data + sge->length;
 249         }
 250 }
 251
 252 static inline void sk_msg_page_add(struct sk_msg *msg, struct page *page,
 253                                    u32 len, u32 offset)
 254 {
 255         struct scatterlist *sge;
 256
 257         get_page(page);
 258         sge = sk_msg_elem(msg, msg->sg.end);
 259         sg_set_page(sge, page, len, offset);
 260         sg_unmark_end(sge);
 261
 262         __set_bit(msg->sg.end, msg->sg.copy);
 263         msg->sg.size += len;
 264         sk_msg_iter_next(msg, end);
 265 }
 266
 267 static inline void sk_msg_sg_copy(struct sk_msg *msg, u32 i, bool copy_state)
 268 {
 269         do {
 270                 if (copy_state)
 271                         __set_bit(i, msg->sg.copy);
 272                 else
 273                         __clear_bit(i, msg->sg.copy);
 274                 sk_msg_iter_var_next(i);
 275                 if (i == msg->sg.end)
 276                         break;
 277         } while (1);
 278 }
 279
 280 static inline void sk_msg_sg_copy_set(struct sk_msg *msg, u32 start)
 281 {
 282         sk_msg_sg_copy(msg, start, true);
 283 }
 284
 285 static inline void sk_msg_sg_copy_clear(struct sk_msg *msg, u32 start)
 286 {
 287         sk_msg_sg_copy(msg, start, false);
 288 }
 289
 290 static inline struct sk_psock *sk_psock(const struct sock *sk)
 291 {
 292         return __rcu_dereference_sk_user_data_with_flags(sk,
 293                                                          SK_USER_DATA_PSOCK);
 294 }
 295
 296 static inline void sk_psock_set_state(struct sk_psock *psock,
 297                                       enum sk_psock_state_bits bit)
 298 {
 299         set_bit(bit, &psock->state);
 300 }
 301
 302 static inline void sk_psock_clear_state(struct sk_psock *psock,
 303                                         enum sk_psock_state_bits bit)
 304 {
 305         clear_bit(bit, &psock->state);
 306 }
 307
 308 static inline bool sk_psock_test_state(const struct sk_psock *psock,
 309                                        enum sk_psock_state_bits bit)
 310 {
 311         return test_bit(bit, &psock->state);
 312 }
 313
 314 static inline void sock_drop(struct sock *sk, struct sk_buff *skb)
 315 {
 316         sk_drops_add(sk, skb);
 317         kfree_skb(skb);
 318 }
 319
 320 static inline void sk_psock_queue_msg(struct sk_psock *psock,
 321                                       struct sk_msg *msg)
 322 {
 323         spin_lock_bh(&psock->ingress_lock);
 324         if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
 325                 list_add_tail(&msg->list, &psock->ingress_msg);
 326         else {
 327                 sk_msg_free(psock->sk, msg);
 328                 kfree(msg);
 329         }
 330         spin_unlock_bh(&psock->ingress_lock);
 331 }
 332
 333 static inline struct sk_msg *sk_psock_dequeue_msg(struct sk_psock *psock)
 334 {
 335         struct sk_msg *msg;
 336
 337         spin_lock_bh(&psock->ingress_lock);
 338         msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
 339         if (msg)
 340                 list_del(&msg->list);
 341         spin_unlock_bh(&psock->ingress_lock);
 342         return msg;
 343 }
 344
 345 static inline struct sk_msg *sk_psock_peek_msg(struct sk_psock *psock)
 346 {
 347         struct sk_msg *msg;
 348
 349         spin_lock_bh(&psock->ingress_lock);
 350         msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
 351         spin_unlock_bh(&psock->ingress_lock);
 352         return msg;
 353 }
 354
 355 static inline struct sk_msg *sk_psock_next_msg(struct sk_psock *psock,
 356                                                struct sk_msg *msg)
 357 {
 358         struct sk_msg *ret;
 359
 360         spin_lock_bh(&psock->ingress_lock);
 361         if (list_is_last(&msg->list, &psock->ingress_msg))
 362                 ret = NULL;
 363         else
 364                 ret = list_next_entry(msg, list);
 365         spin_unlock_bh(&psock->ingress_lock);
 366         return ret;
 367 }
 368
 369 static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
 370 {
 371         return psock ? list_empty(&psock->ingress_msg) : true;
 372 }
 373
 374 static inline void kfree_sk_msg(struct sk_msg *msg)
 375 {
 376         if (msg->skb)
 377                 consume_skb(msg->skb);
 378         kfree(msg);
 379 }
 380
 381 static inline void sk_psock_report_error(struct sk_psock *psock, int err)
 382 {
 383         struct sock *sk = psock->sk;
 384
 385         sk->sk_err = err;
 386         sk_error_report(sk);
 387 }
 388
 389 struct sk_psock *sk_psock_init(struct sock *sk, int node);
 390 void sk_psock_stop(struct sk_psock *psock);
 391
 392 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
 393 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
 394 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
 395 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
 396 #else
 397 static inline int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
 398 {
 399         return -EOPNOTSUPP;
 400 }
 401
 402 static inline void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
 403 {
 404 }
 405
 406 static inline void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
 407 {
 408 }
 409 #endif
 410
 411 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock);
 412 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock);
 413
 414 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
 415                          struct sk_msg *msg);
 416
 417 /*
 418  * This specialized allocator has to be a macro for its allocations to be
 419  * accounted separately (to have a separate alloc_tag). The typecast is
 420  * intentional to enforce typesafety.
 421  */
 422 #define sk_psock_init_link()    \
 423                 ((struct sk_psock_link *)kzalloc(sizeof(struct sk_psock_link),  \
 424                                                  GFP_ATOMIC | __GFP_NOWARN))
 425
 426 static inline void sk_psock_free_link(struct sk_psock_link *link)
 427 {
 428         kfree(link);
 429 }
 430
 431 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock);
 432
 433 static inline void sk_psock_cork_free(struct sk_psock *psock)
 434 {
 435         if (psock->cork) {
 436                 sk_msg_free(psock->sk, psock->cork);
 437                 kfree(psock->cork);
 438                 psock->cork = NULL;
 439         }
 440 }
 441
 442 static inline void sk_psock_restore_proto(struct sock *sk,
 443                                           struct sk_psock *psock)
 444 {
 445         if (psock->psock_update_sk_prot)
 446                 psock->psock_update_sk_prot(sk, psock, true);
 447 }
 448
 449 static inline struct sk_psock *sk_psock_get(struct sock *sk)
 450 {
 451         struct sk_psock *psock;
 452
 453         rcu_read_lock();
 454         psock = sk_psock(sk);
 455         if (psock && !refcount_inc_not_zero(&psock->refcnt))
 456                 psock = NULL;
 457         rcu_read_unlock();
 458         return psock;
 459 }
 460
 461 void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
 462
 463 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
 464 {
 465         if (refcount_dec_and_test(&psock->refcnt))
 466                 sk_psock_drop(sk, psock);
 467 }
 468
 469 static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)
 470 {
 471         read_lock_bh(&sk->sk_callback_lock);
 472         if (psock->saved_data_ready)
 473                 psock->saved_data_ready(sk);
 474         else
 475                 sk->sk_data_ready(sk);
 476         read_unlock_bh(&sk->sk_callback_lock);
 477 }
 478
 479 static inline void psock_set_prog(struct bpf_prog **pprog,
 480                                   struct bpf_prog *prog)
 481 {
 482         prog = xchg(pprog, prog);
 483         if (prog)
 484                 bpf_prog_put(prog);
 485 }
 486
 487 static inline int psock_replace_prog(struct bpf_prog **pprog,
 488                                      struct bpf_prog *prog,
 489                                      struct bpf_prog *old)
 490 {
 491         if (cmpxchg(pprog, old, prog) != old)
 492                 return -ENOENT;
 493
 494         if (old)
 495                 bpf_prog_put(old);
 496
 497         return 0;
 498 }
 499
 500 static inline void psock_progs_drop(struct sk_psock_progs *progs)
 501 {
 502         psock_set_prog(&progs->msg_parser, NULL);
 503         psock_set_prog(&progs->stream_parser, NULL);
 504         psock_set_prog(&progs->stream_verdict, NULL);
 505         psock_set_prog(&progs->skb_verdict, NULL);
 506 }
 507
 508 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb);
 509
 510 static inline bool sk_psock_strp_enabled(struct sk_psock *psock)
 511 {
 512         if (!psock)
 513                 return false;
 514         return !!psock->saved_data_ready;
 515 }
 516
 517 #if IS_ENABLED(CONFIG_NET_SOCK_MSG)
 518
 519 #define BPF_F_STRPARSER (1UL << 1)
 520
 521 /* We only have two bits so far. */
 522 #define BPF_F_PTR_MASK ~(BPF_F_INGRESS | BPF_F_STRPARSER)
 523
 524 static inline bool skb_bpf_strparser(const struct sk_buff *skb)
 525 {
 526         unsigned long sk_redir = skb->_sk_redir;
 527
 528         return sk_redir & BPF_F_STRPARSER;
 529 }
 530
 531 static inline void skb_bpf_set_strparser(struct sk_buff *skb)
 532 {
 533         skb->_sk_redir |= BPF_F_STRPARSER;
 534 }
 535
 536 static inline bool skb_bpf_ingress(const struct sk_buff *skb)
 537 {
 538         unsigned long sk_redir = skb->_sk_redir;
 539
 540         return sk_redir & BPF_F_INGRESS;
 541 }
 542
 543 static inline void skb_bpf_set_ingress(struct sk_buff *skb)
 544 {
 545         skb->_sk_redir |= BPF_F_INGRESS;
 546 }
 547
 548 static inline void skb_bpf_set_redir(struct sk_buff *skb, struct sock *sk_redir,
 549                                      bool ingress)
 550 {
 551         skb->_sk_redir = (unsigned long)sk_redir;
 552         if (ingress)
 553                 skb->_sk_redir |= BPF_F_INGRESS;
 554 }
 555
 556 static inline struct sock *skb_bpf_redirect_fetch(const struct sk_buff *skb)
 557 {
 558         unsigned long sk_redir = skb->_sk_redir;
 559
 560         return (struct sock *)(sk_redir & BPF_F_PTR_MASK);
 561 }
 562
 563 static inline void skb_bpf_redirect_clear(struct sk_buff *skb)
 564 {
 565         skb->_sk_redir = 0;
 566 }
 567 #endif /* CONFIG_NET_SOCK_MSG */
 568 #endif /* _LINUX_SKMSG_H */