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