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         u32                             copied_seq;
  95         u32                             ingress_bytes;
  96 #endif
  97         struct sk_buff_head             ingress_skb;
  98         struct list_head                ingress_msg;
  99         spinlock_t                      ingress_lock;
 100         unsigned long                   state;
 101         struct list_head                link;
 102         spinlock_t                      link_lock;
 103         refcount_t                      refcnt;
 104         void (*saved_unhash)(struct sock *sk);
 105         void (*saved_destroy)(struct sock *sk);
 106         void (*saved_close)(struct sock *sk, long timeout);
 107         void (*saved_write_space)(struct sock *sk);
 108         void (*saved_data_ready)(struct sock *sk);
 109         /* psock_update_sk_prot may be called with restore=false many times
 110          * so the handler must be safe for this case. It will be called
 111          * exactly once with restore=true when the psock is being destroyed
 112          * and psock refcnt is zero, but before an RCU grace period.
 113          */
 114         int  (*psock_update_sk_prot)(struct sock *sk, struct sk_psock *psock,
 115                                      bool restore);
 116         struct proto                    *sk_proto;
 117         struct mutex                    work_mutex;
 118         struct sk_psock_work_state      work_state;
 119         struct delayed_work             work;
 120         struct sock                     *sk_pair;
 121         struct rcu_work                 rwork;
 122 };
 123
 124 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
 125                  int elem_first_coalesce);
 126 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
 127                  u32 off, u32 len);
 128 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len);
 129 int sk_msg_free(struct sock *sk, struct sk_msg *msg);
 130 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg);
 131 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes);
 132 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
 133                                   u32 bytes);
 134
 135 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes);
 136 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes);
 137
 138 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
 139                               struct sk_msg *msg, u32 bytes);
 140 int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
 141                              struct sk_msg *msg, u32 bytes);
 142 int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
 143                    int len, int flags);
 144 bool sk_msg_is_readable(struct sock *sk);
 145
 146 static inline void sk_msg_check_to_free(struct sk_msg *msg, u32 i, u32 bytes)
 147 {
 148         WARN_ON(i == msg->sg.end && bytes);
 149 }
 150
 151 static inline void sk_msg_apply_bytes(struct sk_psock *psock, u32 bytes)
 152 {
 153         if (psock->apply_bytes) {
 154                 if (psock->apply_bytes < bytes)
 155                         psock->apply_bytes = 0;
 156                 else
 157                         psock->apply_bytes -= bytes;
 158         }
 159 }
 160
 161 static inline u32 sk_msg_iter_dist(u32 start, u32 end)
 162 {
 163         return end >= start ? end - start : end + (NR_MSG_FRAG_IDS - start);
 164 }
 165
 166 #define sk_msg_iter_var_prev(var)                       \
 167         do {                                            \
 168                 if (var == 0)                           \
 169                         var = NR_MSG_FRAG_IDS - 1;      \
 170                 else                                    \
 171                         var--;                          \
 172         } while (0)
 173
 174 #define sk_msg_iter_var_next(var)                       \
 175         do {                                            \
 176                 var++;                                  \
 177                 if (var == NR_MSG_FRAG_IDS)             \
 178                         var = 0;                        \
 179         } while (0)
 180
 181 #define sk_msg_iter_prev(msg, which)                    \
 182         sk_msg_iter_var_prev(msg->sg.which)
 183
 184 #define sk_msg_iter_next(msg, which)                    \
 185         sk_msg_iter_var_next(msg->sg.which)
 186
 187 static inline void sk_msg_init(struct sk_msg *msg)
 188 {
 189         BUILD_BUG_ON(ARRAY_SIZE(msg->sg.data) - 1 != NR_MSG_FRAG_IDS);
 190         memset(msg, 0, sizeof(*msg));
 191         sg_init_marker(msg->sg.data, NR_MSG_FRAG_IDS);
 192 }
 193
 194 static inline void sk_msg_xfer(struct sk_msg *dst, struct sk_msg *src,
 195                                int which, u32 size)
 196 {
 197         dst->sg.data[which] = src->sg.data[which];
 198         dst->sg.data[which].length  = size;
 199         dst->sg.size               += size;
 200         src->sg.size               -= size;
 201         src->sg.data[which].length -= size;
 202         src->sg.data[which].offset += size;
 203 }
 204
 205 static inline void sk_msg_xfer_full(struct sk_msg *dst, struct sk_msg *src)
 206 {
 207         memcpy(dst, src, sizeof(*src));
 208         sk_msg_init(src);
 209 }
 210
 211 static inline bool sk_msg_full(const struct sk_msg *msg)
 212 {
 213         return sk_msg_iter_dist(msg->sg.start, msg->sg.end) == MAX_MSG_FRAGS;
 214 }
 215
 216 static inline u32 sk_msg_elem_used(const struct sk_msg *msg)
 217 {
 218         return sk_msg_iter_dist(msg->sg.start, msg->sg.end);
 219 }
 220
 221 static inline struct scatterlist *sk_msg_elem(struct sk_msg *msg, int which)
 222 {
 223         return &msg->sg.data[which];
 224 }
 225
 226 static inline struct scatterlist sk_msg_elem_cpy(struct sk_msg *msg, int which)
 227 {
 228         return msg->sg.data[which];
 229 }
 230
 231 static inline struct page *sk_msg_page(struct sk_msg *msg, int which)
 232 {
 233         return sg_page(sk_msg_elem(msg, which));
 234 }
 235
 236 static inline bool sk_msg_to_ingress(const struct sk_msg *msg)
 237 {
 238         return msg->flags & BPF_F_INGRESS;
 239 }
 240
 241 static inline void sk_msg_compute_data_pointers(struct sk_msg *msg)
 242 {
 243         struct scatterlist *sge = sk_msg_elem(msg, msg->sg.start);
 244
 245         if (test_bit(msg->sg.start, msg->sg.copy)) {
 246                 msg->data = NULL;
 247                 msg->data_end = NULL;
 248         } else {
 249                 msg->data = sg_virt(sge);
 250                 msg->data_end = msg->data + sge->length;
 251         }
 252 }
 253
 254 static inline void sk_msg_page_add(struct sk_msg *msg, struct page *page,
 255                                    u32 len, u32 offset)
 256 {
 257         struct scatterlist *sge;
 258
 259         get_page(page);
 260         sge = sk_msg_elem(msg, msg->sg.end);
 261         sg_set_page(sge, page, len, offset);
 262         sg_unmark_end(sge);
 263
 264         __set_bit(msg->sg.end, msg->sg.copy);
 265         msg->sg.size += len;
 266         sk_msg_iter_next(msg, end);
 267 }
 268
 269 static inline void sk_msg_sg_copy(struct sk_msg *msg, u32 i, bool copy_state)
 270 {
 271         do {
 272                 if (copy_state)
 273                         __set_bit(i, msg->sg.copy);
 274                 else
 275                         __clear_bit(i, msg->sg.copy);
 276                 sk_msg_iter_var_next(i);
 277                 if (i == msg->sg.end)
 278                         break;
 279         } while (1);
 280 }
 281
 282 static inline void sk_msg_sg_copy_set(struct sk_msg *msg, u32 start)
 283 {
 284         sk_msg_sg_copy(msg, start, true);
 285 }
 286
 287 static inline void sk_msg_sg_copy_clear(struct sk_msg *msg, u32 start)
 288 {
 289         sk_msg_sg_copy(msg, start, false);
 290 }
 291
 292 static inline struct sk_psock *sk_psock(const struct sock *sk)
 293 {
 294         return __rcu_dereference_sk_user_data_with_flags(sk,
 295                                                          SK_USER_DATA_PSOCK);
 296 }
 297
 298 static inline void sk_psock_set_state(struct sk_psock *psock,
 299                                       enum sk_psock_state_bits bit)
 300 {
 301         set_bit(bit, &psock->state);
 302 }
 303
 304 static inline void sk_psock_clear_state(struct sk_psock *psock,
 305                                         enum sk_psock_state_bits bit)
 306 {
 307         clear_bit(bit, &psock->state);
 308 }
 309
 310 static inline bool sk_psock_test_state(const struct sk_psock *psock,
 311                                        enum sk_psock_state_bits bit)
 312 {
 313         return test_bit(bit, &psock->state);
 314 }
 315
 316 static inline void sock_drop(struct sock *sk, struct sk_buff *skb)
 317 {
 318         sk_drops_add(sk, skb);
 319         kfree_skb(skb);
 320 }
 321
 322 static inline bool sk_psock_queue_msg(struct sk_psock *psock,
 323                                       struct sk_msg *msg)
 324 {
 325         bool ret;
 326
 327         spin_lock_bh(&psock->ingress_lock);
 328         if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
 329                 list_add_tail(&msg->list, &psock->ingress_msg);
 330                 ret = true;
 331         } else {
 332                 sk_msg_free(psock->sk, msg);
 333                 kfree(msg);
 334                 ret = false;
 335         }
 336         spin_unlock_bh(&psock->ingress_lock);
 337         return ret;
 338 }
 339
 340 static inline struct sk_msg *sk_psock_dequeue_msg(struct sk_psock *psock)
 341 {
 342         struct sk_msg *msg;
 343
 344         spin_lock_bh(&psock->ingress_lock);
 345         msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
 346         if (msg)
 347                 list_del(&msg->list);
 348         spin_unlock_bh(&psock->ingress_lock);
 349         return msg;
 350 }
 351
 352 static inline struct sk_msg *sk_psock_peek_msg(struct sk_psock *psock)
 353 {
 354         struct sk_msg *msg;
 355
 356         spin_lock_bh(&psock->ingress_lock);
 357         msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
 358         spin_unlock_bh(&psock->ingress_lock);
 359         return msg;
 360 }
 361
 362 static inline struct sk_msg *sk_psock_next_msg(struct sk_psock *psock,
 363                                                struct sk_msg *msg)
 364 {
 365         struct sk_msg *ret;
 366
 367         spin_lock_bh(&psock->ingress_lock);
 368         if (list_is_last(&msg->list, &psock->ingress_msg))
 369                 ret = NULL;
 370         else
 371                 ret = list_next_entry(msg, list);
 372         spin_unlock_bh(&psock->ingress_lock);
 373         return ret;
 374 }
 375
 376 static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
 377 {
 378         return psock ? list_empty(&psock->ingress_msg) : true;
 379 }
 380
 381 static inline void kfree_sk_msg(struct sk_msg *msg)
 382 {
 383         if (msg->skb)
 384                 consume_skb(msg->skb);
 385         kfree(msg);
 386 }
 387
 388 static inline void sk_psock_report_error(struct sk_psock *psock, int err)
 389 {
 390         struct sock *sk = psock->sk;
 391
 392         sk->sk_err = err;
 393         sk_error_report(sk);
 394 }
 395
 396 struct sk_psock *sk_psock_init(struct sock *sk, int node);
 397 void sk_psock_stop(struct sk_psock *psock);
 398
 399 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
 400 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
 401 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
 402 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
 403 #else
 404 static inline int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
 405 {
 406         return -EOPNOTSUPP;
 407 }
 408
 409 static inline void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
 410 {
 411 }
 412
 413 static inline void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
 414 {
 415 }
 416 #endif
 417
 418 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock);
 419 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock);
 420
 421 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
 422                          struct sk_msg *msg);
 423
 424 /*
 425  * This specialized allocator has to be a macro for its allocations to be
 426  * accounted separately (to have a separate alloc_tag). The typecast is
 427  * intentional to enforce typesafety.
 428  */
 429 #define sk_psock_init_link()    \
 430                 ((struct sk_psock_link *)kzalloc(sizeof(struct sk_psock_link),  \
 431                                                  GFP_ATOMIC | __GFP_NOWARN))
 432
 433 static inline void sk_psock_free_link(struct sk_psock_link *link)
 434 {
 435         kfree(link);
 436 }
 437
 438 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock);
 439
 440 static inline void sk_psock_cork_free(struct sk_psock *psock)
 441 {
 442         if (psock->cork) {
 443                 sk_msg_free(psock->sk, psock->cork);
 444                 kfree(psock->cork);
 445                 psock->cork = NULL;
 446         }
 447 }
 448
 449 static inline void sk_psock_restore_proto(struct sock *sk,
 450                                           struct sk_psock *psock)
 451 {
 452         if (psock->psock_update_sk_prot)
 453                 psock->psock_update_sk_prot(sk, psock, true);
 454 }
 455
 456 static inline struct sk_psock *sk_psock_get(struct sock *sk)
 457 {
 458         struct sk_psock *psock;
 459
 460         rcu_read_lock();
 461         psock = sk_psock(sk);
 462         if (psock && !refcount_inc_not_zero(&psock->refcnt))
 463                 psock = NULL;
 464         rcu_read_unlock();
 465         return psock;
 466 }
 467
 468 void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
 469
 470 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
 471 {
 472         if (refcount_dec_and_test(&psock->refcnt))
 473                 sk_psock_drop(sk, psock);
 474 }
 475
 476 static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)
 477 {
 478         read_lock_bh(&sk->sk_callback_lock);
 479         if (psock->saved_data_ready)
 480                 psock->saved_data_ready(sk);
 481         else
 482                 sk->sk_data_ready(sk);
 483         read_unlock_bh(&sk->sk_callback_lock);
 484 }
 485
 486 static inline void psock_set_prog(struct bpf_prog **pprog,
 487                                   struct bpf_prog *prog)
 488 {
 489         prog = xchg(pprog, prog);
 490         if (prog)
 491                 bpf_prog_put(prog);
 492 }
 493
 494 static inline int psock_replace_prog(struct bpf_prog **pprog,
 495                                      struct bpf_prog *prog,
 496                                      struct bpf_prog *old)
 497 {
 498         if (cmpxchg(pprog, old, prog) != old)
 499                 return -ENOENT;
 500
 501         if (old)
 502                 bpf_prog_put(old);
 503
 504         return 0;
 505 }
 506
 507 static inline void psock_progs_drop(struct sk_psock_progs *progs)
 508 {
 509         psock_set_prog(&progs->msg_parser, NULL);
 510         psock_set_prog(&progs->stream_parser, NULL);
 511         psock_set_prog(&progs->stream_verdict, NULL);
 512         psock_set_prog(&progs->skb_verdict, NULL);
 513 }
 514
 515 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb);
 516
 517 static inline bool sk_psock_strp_enabled(struct sk_psock *psock)
 518 {
 519         if (!psock)
 520                 return false;
 521         return !!psock->saved_data_ready;
 522 }
 523
 524 #if IS_ENABLED(CONFIG_NET_SOCK_MSG)
 525
 526 #define BPF_F_STRPARSER (1UL << 1)
 527
 528 /* We only have two bits so far. */
 529 #define BPF_F_PTR_MASK ~(BPF_F_INGRESS | BPF_F_STRPARSER)
 530
 531 static inline bool skb_bpf_strparser(const struct sk_buff *skb)
 532 {
 533         unsigned long sk_redir = skb->_sk_redir;
 534
 535         return sk_redir & BPF_F_STRPARSER;
 536 }
 537
 538 static inline void skb_bpf_set_strparser(struct sk_buff *skb)
 539 {
 540         skb->_sk_redir |= BPF_F_STRPARSER;
 541 }
 542
 543 static inline bool skb_bpf_ingress(const struct sk_buff *skb)
 544 {
 545         unsigned long sk_redir = skb->_sk_redir;
 546
 547         return sk_redir & BPF_F_INGRESS;
 548 }
 549
 550 static inline void skb_bpf_set_ingress(struct sk_buff *skb)
 551 {
 552         skb->_sk_redir |= BPF_F_INGRESS;
 553 }
 554
 555 static inline void skb_bpf_set_redir(struct sk_buff *skb, struct sock *sk_redir,
 556                                      bool ingress)
 557 {
 558         skb->_sk_redir = (unsigned long)sk_redir;
 559         if (ingress)
 560                 skb->_sk_redir |= BPF_F_INGRESS;
 561 }
 562
 563 static inline struct sock *skb_bpf_redirect_fetch(const struct sk_buff *skb)
 564 {
 565         unsigned long sk_redir = skb->_sk_redir;
 566
 567         return (struct sock *)(sk_redir & BPF_F_PTR_MASK);
 568 }
 569
 570 static inline void skb_bpf_redirect_clear(struct sk_buff *skb)
 571 {
 572         skb->_sk_redir = 0;
 573 }
 574 #endif /* CONFIG_NET_SOCK_MSG */
 575 #endif /* _LINUX_SKMSG_H */