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         unsigned long                   copy;
  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 static_assert(BITS_PER_LONG >= NR_MSG_FRAG_IDS);
  42
  43 /* UAPI in filter.c depends on struct sk_msg_sg being first element. */
  44 struct sk_msg {
  45         struct sk_msg_sg                sg;
  46         void                            *data;
  47         void                            *data_end;
  48         u32                             apply_bytes;
  49         u32                             cork_bytes;
  50         u32                             flags;
  51         struct sk_buff                  *skb;
  52         struct sock                     *sk_redir;
  53         struct sock                     *sk;
  54         struct list_head                list;
  55 };
  56
  57 struct sk_psock_progs {
  58         struct bpf_prog                 *msg_parser;
  59         struct bpf_prog                 *stream_parser;
  60         struct bpf_prog                 *stream_verdict;
  61         struct bpf_prog                 *skb_verdict;
  62 };
  63
  64 enum sk_psock_state_bits {
  65         SK_PSOCK_TX_ENABLED,
  66 };
  67
  68 struct sk_psock_link {
  69         struct list_head                list;
  70         struct bpf_map                  *map;
  71         void                            *link_raw;
  72 };
  73
  74 struct sk_psock_work_state {
  75         struct sk_buff                  *skb;
  76         u32                             len;
  77         u32                             off;
  78 };
  79
  80 struct sk_psock {
  81         struct sock                     *sk;
  82         struct sock                     *sk_redir;
  83         u32                             apply_bytes;
  84         u32                             cork_bytes;
  85         u32                             eval;
  86         struct sk_msg                   *cork;
  87         struct sk_psock_progs           progs;
  88 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
  89         struct strparser                strp;
  90 #endif
  91         struct sk_buff_head             ingress_skb;
  92         struct list_head                ingress_msg;
  93         spinlock_t                      ingress_lock;
  94         unsigned long                   state;
  95         struct list_head                link;
  96         spinlock_t                      link_lock;
  97         refcount_t                      refcnt;
  98         void (*saved_unhash)(struct sock *sk);
  99         void (*saved_close)(struct sock *sk, long timeout);
 100         void (*saved_write_space)(struct sock *sk);
 101         void (*saved_data_ready)(struct sock *sk);
 102         struct proto                    *sk_proto;
 103         struct mutex                    work_mutex;
 104         struct sk_psock_work_state      work_state;
 105         struct work_struct              work;
 106         struct rcu_work                 rwork;
 107 };
 108
 109 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
 110                  int elem_first_coalesce);
 111 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
 112                  u32 off, u32 len);
 113 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len);
 114 int sk_msg_free(struct sock *sk, struct sk_msg *msg);
 115 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg);
 116 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes);
 117 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
 118                                   u32 bytes);
 119
 120 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes);
 121 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes);
 122
 123 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
 124                               struct sk_msg *msg, u32 bytes);
 125 int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
 126                              struct sk_msg *msg, u32 bytes);
 127
 128 static inline void sk_msg_check_to_free(struct sk_msg *msg, u32 i, u32 bytes)
 129 {
 130         WARN_ON(i == msg->sg.end && bytes);
 131 }
 132
 133 static inline void sk_msg_apply_bytes(struct sk_psock *psock, u32 bytes)
 134 {
 135         if (psock->apply_bytes) {
 136                 if (psock->apply_bytes < bytes)
 137                         psock->apply_bytes = 0;
 138                 else
 139                         psock->apply_bytes -= bytes;
 140         }
 141 }
 142
 143 static inline u32 sk_msg_iter_dist(u32 start, u32 end)
 144 {
 145         return end >= start ? end - start : end + (NR_MSG_FRAG_IDS - start);
 146 }
 147
 148 #define sk_msg_iter_var_prev(var)                       \
 149         do {                                            \
 150                 if (var == 0)                           \
 151                         var = NR_MSG_FRAG_IDS - 1;      \
 152                 else                                    \
 153                         var--;                          \
 154         } while (0)
 155
 156 #define sk_msg_iter_var_next(var)                       \
 157         do {                                            \
 158                 var++;                                  \
 159                 if (var == NR_MSG_FRAG_IDS)             \
 160                         var = 0;                        \
 161         } while (0)
 162
 163 #define sk_msg_iter_prev(msg, which)                    \
 164         sk_msg_iter_var_prev(msg->sg.which)
 165
 166 #define sk_msg_iter_next(msg, which)                    \
 167         sk_msg_iter_var_next(msg->sg.which)
 168
 169 static inline void sk_msg_clear_meta(struct sk_msg *msg)
 170 {
 171         memset(&msg->sg, 0, offsetofend(struct sk_msg_sg, copy));
 172 }
 173
 174 static inline void sk_msg_init(struct sk_msg *msg)
 175 {
 176         BUILD_BUG_ON(ARRAY_SIZE(msg->sg.data) - 1 != NR_MSG_FRAG_IDS);
 177         memset(msg, 0, sizeof(*msg));
 178         sg_init_marker(msg->sg.data, NR_MSG_FRAG_IDS);
 179 }
 180
 181 static inline void sk_msg_xfer(struct sk_msg *dst, struct sk_msg *src,
 182                                int which, u32 size)
 183 {
 184         dst->sg.data[which] = src->sg.data[which];
 185         dst->sg.data[which].length  = size;
 186         dst->sg.size               += size;
 187         src->sg.size               -= size;
 188         src->sg.data[which].length -= size;
 189         src->sg.data[which].offset += size;
 190 }
 191
 192 static inline void sk_msg_xfer_full(struct sk_msg *dst, struct sk_msg *src)
 193 {
 194         memcpy(dst, src, sizeof(*src));
 195         sk_msg_init(src);
 196 }
 197
 198 static inline bool sk_msg_full(const struct sk_msg *msg)
 199 {
 200         return sk_msg_iter_dist(msg->sg.start, msg->sg.end) == MAX_MSG_FRAGS;
 201 }
 202
 203 static inline u32 sk_msg_elem_used(const struct sk_msg *msg)
 204 {
 205         return sk_msg_iter_dist(msg->sg.start, msg->sg.end);
 206 }
 207
 208 static inline struct scatterlist *sk_msg_elem(struct sk_msg *msg, int which)
 209 {
 210         return &msg->sg.data[which];
 211 }
 212
 213 static inline struct scatterlist sk_msg_elem_cpy(struct sk_msg *msg, int which)
 214 {
 215         return msg->sg.data[which];
 216 }
 217
 218 static inline struct page *sk_msg_page(struct sk_msg *msg, int which)
 219 {
 220         return sg_page(sk_msg_elem(msg, which));
 221 }
 222
 223 static inline bool sk_msg_to_ingress(const struct sk_msg *msg)
 224 {
 225         return msg->flags & BPF_F_INGRESS;
 226 }
 227
 228 static inline void sk_msg_compute_data_pointers(struct sk_msg *msg)
 229 {
 230         struct scatterlist *sge = sk_msg_elem(msg, msg->sg.start);
 231
 232         if (test_bit(msg->sg.start, &msg->sg.copy)) {
 233                 msg->data = NULL;
 234                 msg->data_end = NULL;
 235         } else {
 236                 msg->data = sg_virt(sge);
 237                 msg->data_end = msg->data + sge->length;
 238         }
 239 }
 240
 241 static inline void sk_msg_page_add(struct sk_msg *msg, struct page *page,
 242                                    u32 len, u32 offset)
 243 {
 244         struct scatterlist *sge;
 245
 246         get_page(page);
 247         sge = sk_msg_elem(msg, msg->sg.end);
 248         sg_set_page(sge, page, len, offset);
 249         sg_unmark_end(sge);
 250
 251         __set_bit(msg->sg.end, &msg->sg.copy);
 252         msg->sg.size += len;
 253         sk_msg_iter_next(msg, end);
 254 }
 255
 256 static inline void sk_msg_sg_copy(struct sk_msg *msg, u32 i, bool copy_state)
 257 {
 258         do {
 259                 if (copy_state)
 260                         __set_bit(i, &msg->sg.copy);
 261                 else
 262                         __clear_bit(i, &msg->sg.copy);
 263                 sk_msg_iter_var_next(i);
 264                 if (i == msg->sg.end)
 265                         break;
 266         } while (1);
 267 }
 268
 269 static inline void sk_msg_sg_copy_set(struct sk_msg *msg, u32 start)
 270 {
 271         sk_msg_sg_copy(msg, start, true);
 272 }
 273
 274 static inline void sk_msg_sg_copy_clear(struct sk_msg *msg, u32 start)
 275 {
 276         sk_msg_sg_copy(msg, start, false);
 277 }
 278
 279 static inline struct sk_psock *sk_psock(const struct sock *sk)
 280 {
 281         return rcu_dereference_sk_user_data(sk);
 282 }
 283
 284 static inline void sk_psock_queue_msg(struct sk_psock *psock,
 285                                       struct sk_msg *msg)
 286 {
 287         spin_lock_bh(&psock->ingress_lock);
 288         list_add_tail(&msg->list, &psock->ingress_msg);
 289         spin_unlock_bh(&psock->ingress_lock);
 290 }
 291
 292 static inline struct sk_msg *sk_psock_dequeue_msg(struct sk_psock *psock)
 293 {
 294         struct sk_msg *msg;
 295
 296         spin_lock_bh(&psock->ingress_lock);
 297         msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
 298         if (msg)
 299                 list_del(&msg->list);
 300         spin_unlock_bh(&psock->ingress_lock);
 301         return msg;
 302 }
 303
 304 static inline struct sk_msg *sk_psock_peek_msg(struct sk_psock *psock)
 305 {
 306         struct sk_msg *msg;
 307
 308         spin_lock_bh(&psock->ingress_lock);
 309         msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
 310         spin_unlock_bh(&psock->ingress_lock);
 311         return msg;
 312 }
 313
 314 static inline struct sk_msg *sk_psock_next_msg(struct sk_psock *psock,
 315                                                struct sk_msg *msg)
 316 {
 317         struct sk_msg *ret;
 318
 319         spin_lock_bh(&psock->ingress_lock);
 320         if (list_is_last(&msg->list, &psock->ingress_msg))
 321                 ret = NULL;
 322         else
 323                 ret = list_next_entry(msg, list);
 324         spin_unlock_bh(&psock->ingress_lock);
 325         return ret;
 326 }
 327
 328 static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
 329 {
 330         return psock ? list_empty(&psock->ingress_msg) : true;
 331 }
 332
 333 static inline void kfree_sk_msg(struct sk_msg *msg)
 334 {
 335         if (msg->skb)
 336                 consume_skb(msg->skb);
 337         kfree(msg);
 338 }
 339
 340 static inline void sk_psock_report_error(struct sk_psock *psock, int err)
 341 {
 342         struct sock *sk = psock->sk;
 343
 344         sk->sk_err = err;
 345         sk->sk_error_report(sk);
 346 }
 347
 348 struct sk_psock *sk_psock_init(struct sock *sk, int node);
 349 void sk_psock_stop(struct sk_psock *psock, bool wait);
 350
 351 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
 352 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
 353 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
 354 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
 355 #else
 356 static inline int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
 357 {
 358         return -EOPNOTSUPP;
 359 }
 360
 361 static inline void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
 362 {
 363 }
 364
 365 static inline void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
 366 {
 367 }
 368 #endif
 369
 370 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock);
 371 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock);
 372
 373 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
 374                          struct sk_msg *msg);
 375
 376 static inline struct sk_psock_link *sk_psock_init_link(void)
 377 {
 378         return kzalloc(sizeof(struct sk_psock_link),
 379                        GFP_ATOMIC | __GFP_NOWARN);
 380 }
 381
 382 static inline void sk_psock_free_link(struct sk_psock_link *link)
 383 {
 384         kfree(link);
 385 }
 386
 387 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock);
 388
 389 static inline void sk_psock_cork_free(struct sk_psock *psock)
 390 {
 391         if (psock->cork) {
 392                 sk_msg_free(psock->sk, psock->cork);
 393                 kfree(psock->cork);
 394                 psock->cork = NULL;
 395         }
 396 }
 397
 398 static inline void sk_psock_update_proto(struct sock *sk,
 399                                          struct sk_psock *psock,
 400                                          struct proto *ops)
 401 {
 402         /* Pairs with lockless read in sk_clone_lock() */
 403         WRITE_ONCE(sk->sk_prot, ops);
 404 }
 405
 406 static inline void sk_psock_restore_proto(struct sock *sk,
 407                                           struct sk_psock *psock)
 408 {
 409         sk->sk_prot->unhash = psock->saved_unhash;
 410         if (inet_csk_has_ulp(sk)) {
 411                 tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
 412         } else {
 413                 sk->sk_write_space = psock->saved_write_space;
 414                 /* Pairs with lockless read in sk_clone_lock() */
 415                 WRITE_ONCE(sk->sk_prot, psock->sk_proto);
 416         }
 417 }
 418
 419 static inline void sk_psock_set_state(struct sk_psock *psock,
 420                                       enum sk_psock_state_bits bit)
 421 {
 422         set_bit(bit, &psock->state);
 423 }
 424
 425 static inline void sk_psock_clear_state(struct sk_psock *psock,
 426                                         enum sk_psock_state_bits bit)
 427 {
 428         clear_bit(bit, &psock->state);
 429 }
 430
 431 static inline bool sk_psock_test_state(const struct sk_psock *psock,
 432                                        enum sk_psock_state_bits bit)
 433 {
 434         return test_bit(bit, &psock->state);
 435 }
 436
 437 static inline struct sk_psock *sk_psock_get(struct sock *sk)
 438 {
 439         struct sk_psock *psock;
 440
 441         rcu_read_lock();
 442         psock = sk_psock(sk);
 443         if (psock && !refcount_inc_not_zero(&psock->refcnt))
 444                 psock = NULL;
 445         rcu_read_unlock();
 446         return psock;
 447 }
 448
 449 void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
 450
 451 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
 452 {
 453         if (refcount_dec_and_test(&psock->refcnt))
 454                 sk_psock_drop(sk, psock);
 455 }
 456
 457 static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)
 458 {
 459         if (psock->saved_data_ready)
 460                 psock->saved_data_ready(sk);
 461         else
 462                 sk->sk_data_ready(sk);
 463 }
 464
 465 static inline void psock_set_prog(struct bpf_prog **pprog,
 466                                   struct bpf_prog *prog)
 467 {
 468         prog = xchg(pprog, prog);
 469         if (prog)
 470                 bpf_prog_put(prog);
 471 }
 472
 473 static inline int psock_replace_prog(struct bpf_prog **pprog,
 474                                      struct bpf_prog *prog,
 475                                      struct bpf_prog *old)
 476 {
 477         if (cmpxchg(pprog, old, prog) != old)
 478                 return -ENOENT;
 479
 480         if (old)
 481                 bpf_prog_put(old);
 482
 483         return 0;
 484 }
 485
 486 static inline void psock_progs_drop(struct sk_psock_progs *progs)
 487 {
 488         psock_set_prog(&progs->msg_parser, NULL);
 489         psock_set_prog(&progs->stream_parser, NULL);
 490         psock_set_prog(&progs->stream_verdict, NULL);
 491         psock_set_prog(&progs->skb_verdict, NULL);
 492 }
 493
 494 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb);
 495
 496 static inline bool sk_psock_strp_enabled(struct sk_psock *psock)
 497 {
 498         if (!psock)
 499                 return false;
 500         return !!psock->saved_data_ready;
 501 }
 502
 503 #if IS_ENABLED(CONFIG_NET_SOCK_MSG)
 504
 505 /* We only have one bit so far. */
 506 #define BPF_F_PTR_MASK ~(BPF_F_INGRESS)
 507
 508 static inline bool skb_bpf_ingress(const struct sk_buff *skb)
 509 {
 510         unsigned long sk_redir = skb->_sk_redir;
 511
 512         return sk_redir & BPF_F_INGRESS;
 513 }
 514
 515 static inline void skb_bpf_set_ingress(struct sk_buff *skb)
 516 {
 517         skb->_sk_redir |= BPF_F_INGRESS;
 518 }
 519
 520 static inline void skb_bpf_set_redir(struct sk_buff *skb, struct sock *sk_redir,
 521                                      bool ingress)
 522 {
 523         skb->_sk_redir = (unsigned long)sk_redir;
 524         if (ingress)
 525                 skb->_sk_redir |= BPF_F_INGRESS;
 526 }
 527
 528 static inline struct sock *skb_bpf_redirect_fetch(const struct sk_buff *skb)
 529 {
 530         unsigned long sk_redir = skb->_sk_redir;
 531
 532         return (struct sock *)(sk_redir & BPF_F_PTR_MASK);
 533 }
 534
 535 static inline void skb_bpf_redirect_clear(struct sk_buff *skb)
 536 {
 537         skb->_sk_redir = 0;
 538 }
 539 #endif /* CONFIG_NET_SOCK_MSG */
 540 #endif /* _LINUX_SKMSG_H */