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
  18 enum __sk_action {
  19         __SK_DROP = 0,
  20         __SK_PASS,
  21         __SK_REDIRECT,
  22         __SK_NONE,
  23 };
  24
  25 struct sk_msg_sg {
  26         u32                             start;
  27         u32                             curr;
  28         u32                             end;
  29         u32                             size;
  30         u32                             copybreak;
  31         unsigned long                   copy;
  32         /* The extra element is used for chaining the front and sections when
  33          * the list becomes partitioned (e.g. end < start). The crypto APIs
  34          * require the chaining.
  35          */
  36         struct scatterlist              data[MAX_MSG_FRAGS + 1];
  37 };
  38 static_assert(BITS_PER_LONG >= MAX_MSG_FRAGS);
  39
  40 /* UAPI in filter.c depends on struct sk_msg_sg being first element. */
  41 struct sk_msg {
  42         struct sk_msg_sg                sg;
  43         void                            *data;
  44         void                            *data_end;
  45         u32                             apply_bytes;
  46         u32                             cork_bytes;
  47         u32                             flags;
  48         struct sk_buff                  *skb;
  49         struct sock                     *sk_redir;
  50         struct sock                     *sk;
  51         struct list_head                list;
  52 };
  53
  54 struct sk_psock_progs {
  55         struct bpf_prog                 *msg_parser;
  56         struct bpf_prog                 *skb_parser;
  57         struct bpf_prog                 *skb_verdict;
  58 };
  59
  60 enum sk_psock_state_bits {
  61         SK_PSOCK_TX_ENABLED,
  62 };
  63
  64 struct sk_psock_link {
  65         struct list_head                list;
  66         struct bpf_map                  *map;
  67         void                            *link_raw;
  68 };
  69
  70 struct sk_psock_parser {
  71         struct strparser                strp;
  72         bool                            enabled;
  73         void (*saved_data_ready)(struct sock *sk);
  74 };
  75
  76 struct sk_psock_work_state {
  77         struct sk_buff                  *skb;
  78         u32                             len;
  79         u32                             off;
  80 };
  81
  82 struct sk_psock {
  83         struct sock                     *sk;
  84         struct sock                     *sk_redir;
  85         u32                             apply_bytes;
  86         u32                             cork_bytes;
  87         u32                             eval;
  88         struct sk_msg                   *cork;
  89         struct sk_psock_progs           progs;
  90         struct sk_psock_parser          parser;
  91         struct sk_buff_head             ingress_skb;
  92         struct list_head                ingress_msg;
  93         unsigned long                   state;
  94         struct list_head                link;
  95         spinlock_t                      link_lock;
  96         refcount_t                      refcnt;
  97         void (*saved_unhash)(struct sock *sk);
  98         void (*saved_close)(struct sock *sk, long timeout);
  99         void (*saved_write_space)(struct sock *sk);
 100         struct proto                    *sk_proto;
 101         struct sk_psock_work_state      work_state;
 102         struct work_struct              work;
 103         union {
 104                 struct rcu_head         rcu;
 105                 struct work_struct      gc;
 106         };
 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 + (MAX_MSG_FRAGS - start);
 146 }
 147
 148 #define sk_msg_iter_var_prev(var)                       \
 149         do {                                            \
 150                 if (var == 0)                           \
 151                         var = MAX_MSG_FRAGS - 1;        \
 152                 else                                    \
 153                         var--;                          \
 154         } while (0)
 155
 156 #define sk_msg_iter_var_next(var)                       \
 157         do {                                            \
 158                 var++;                                  \
 159                 if (var == MAX_MSG_FRAGS)               \
 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 != MAX_MSG_FRAGS);
 177         memset(msg, 0, sizeof(*msg));
 178         sg_init_marker(msg->sg.data, MAX_MSG_FRAGS);
 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.data[which].length -= size;
 188         src->sg.data[which].offset += size;
 189 }
 190
 191 static inline void sk_msg_xfer_full(struct sk_msg *dst, struct sk_msg *src)
 192 {
 193         memcpy(dst, src, sizeof(*src));
 194         sk_msg_init(src);
 195 }
 196
 197 static inline bool sk_msg_full(const struct sk_msg *msg)
 198 {
 199         return (msg->sg.end == msg->sg.start) && msg->sg.size;
 200 }
 201
 202 static inline u32 sk_msg_elem_used(const struct sk_msg *msg)
 203 {
 204         if (sk_msg_full(msg))
 205                 return MAX_MSG_FRAGS;
 206
 207         return sk_msg_iter_dist(msg->sg.start, msg->sg.end);
 208 }
 209
 210 static inline struct scatterlist *sk_msg_elem(struct sk_msg *msg, int which)
 211 {
 212         return &msg->sg.data[which];
 213 }
 214
 215 static inline struct scatterlist sk_msg_elem_cpy(struct sk_msg *msg, int which)
 216 {
 217         return msg->sg.data[which];
 218 }
 219
 220 static inline struct page *sk_msg_page(struct sk_msg *msg, int which)
 221 {
 222         return sg_page(sk_msg_elem(msg, which));
 223 }
 224
 225 static inline bool sk_msg_to_ingress(const struct sk_msg *msg)
 226 {
 227         return msg->flags & BPF_F_INGRESS;
 228 }
 229
 230 static inline void sk_msg_compute_data_pointers(struct sk_msg *msg)
 231 {
 232         struct scatterlist *sge = sk_msg_elem(msg, msg->sg.start);
 233
 234         if (test_bit(msg->sg.start, &msg->sg.copy)) {
 235                 msg->data = NULL;
 236                 msg->data_end = NULL;
 237         } else {
 238                 msg->data = sg_virt(sge);
 239                 msg->data_end = msg->data + sge->length;
 240         }
 241 }
 242
 243 static inline void sk_msg_page_add(struct sk_msg *msg, struct page *page,
 244                                    u32 len, u32 offset)
 245 {
 246         struct scatterlist *sge;
 247
 248         get_page(page);
 249         sge = sk_msg_elem(msg, msg->sg.end);
 250         sg_set_page(sge, page, len, offset);
 251         sg_unmark_end(sge);
 252
 253         __set_bit(msg->sg.end, &msg->sg.copy);
 254         msg->sg.size += len;
 255         sk_msg_iter_next(msg, end);
 256 }
 257
 258 static inline void sk_msg_sg_copy(struct sk_msg *msg, u32 i, bool copy_state)
 259 {
 260         do {
 261                 if (copy_state)
 262                         __set_bit(i, &msg->sg.copy);
 263                 else
 264                         __clear_bit(i, &msg->sg.copy);
 265                 sk_msg_iter_var_next(i);
 266                 if (i == msg->sg.end)
 267                         break;
 268         } while (1);
 269 }
 270
 271 static inline void sk_msg_sg_copy_set(struct sk_msg *msg, u32 start)
 272 {
 273         sk_msg_sg_copy(msg, start, true);
 274 }
 275
 276 static inline void sk_msg_sg_copy_clear(struct sk_msg *msg, u32 start)
 277 {
 278         sk_msg_sg_copy(msg, start, false);
 279 }
 280
 281 static inline struct sk_psock *sk_psock(const struct sock *sk)
 282 {
 283         return rcu_dereference_sk_user_data(sk);
 284 }
 285
 286 static inline void sk_psock_queue_msg(struct sk_psock *psock,
 287                                       struct sk_msg *msg)
 288 {
 289         list_add_tail(&msg->list, &psock->ingress_msg);
 290 }
 291
 292 static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
 293 {
 294         return psock ? list_empty(&psock->ingress_msg) : true;
 295 }
 296
 297 static inline void sk_psock_report_error(struct sk_psock *psock, int err)
 298 {
 299         struct sock *sk = psock->sk;
 300
 301         sk->sk_err = err;
 302         sk->sk_error_report(sk);
 303 }
 304
 305 struct sk_psock *sk_psock_init(struct sock *sk, int node);
 306
 307 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
 308 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
 309 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
 310
 311 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
 312                          struct sk_msg *msg);
 313
 314 static inline struct sk_psock_link *sk_psock_init_link(void)
 315 {
 316         return kzalloc(sizeof(struct sk_psock_link),
 317                        GFP_ATOMIC | __GFP_NOWARN);
 318 }
 319
 320 static inline void sk_psock_free_link(struct sk_psock_link *link)
 321 {
 322         kfree(link);
 323 }
 324
 325 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock);
 326 #if defined(CONFIG_BPF_STREAM_PARSER)
 327 void sk_psock_unlink(struct sock *sk, struct sk_psock_link *link);
 328 #else
 329 static inline void sk_psock_unlink(struct sock *sk,
 330                                    struct sk_psock_link *link)
 331 {
 332 }
 333 #endif
 334
 335 void __sk_psock_purge_ingress_msg(struct sk_psock *psock);
 336
 337 static inline void sk_psock_cork_free(struct sk_psock *psock)
 338 {
 339         if (psock->cork) {
 340                 sk_msg_free(psock->sk, psock->cork);
 341                 kfree(psock->cork);
 342                 psock->cork = NULL;
 343         }
 344 }
 345
 346 static inline void sk_psock_update_proto(struct sock *sk,
 347                                          struct sk_psock *psock,
 348                                          struct proto *ops)
 349 {
 350         psock->saved_unhash = sk->sk_prot->unhash;
 351         psock->saved_close = sk->sk_prot->close;
 352         psock->saved_write_space = sk->sk_write_space;
 353
 354         psock->sk_proto = sk->sk_prot;
 355         sk->sk_prot = ops;
 356 }
 357
 358 static inline void sk_psock_restore_proto(struct sock *sk,
 359                                           struct sk_psock *psock)
 360 {
 361         sk->sk_write_space = psock->saved_write_space;
 362
 363         if (psock->sk_proto) {
 364                 struct inet_connection_sock *icsk = inet_csk(sk);
 365                 bool has_ulp = !!icsk->icsk_ulp_data;
 366
 367                 if (has_ulp)
 368                         tcp_update_ulp(sk, psock->sk_proto);
 369                 else
 370                         sk->sk_prot = psock->sk_proto;
 371                 psock->sk_proto = NULL;
 372         }
 373 }
 374
 375 static inline void sk_psock_set_state(struct sk_psock *psock,
 376                                       enum sk_psock_state_bits bit)
 377 {
 378         set_bit(bit, &psock->state);
 379 }
 380
 381 static inline void sk_psock_clear_state(struct sk_psock *psock,
 382                                         enum sk_psock_state_bits bit)
 383 {
 384         clear_bit(bit, &psock->state);
 385 }
 386
 387 static inline bool sk_psock_test_state(const struct sk_psock *psock,
 388                                        enum sk_psock_state_bits bit)
 389 {
 390         return test_bit(bit, &psock->state);
 391 }
 392
 393 static inline struct sk_psock *sk_psock_get_checked(struct sock *sk)
 394 {
 395         struct sk_psock *psock;
 396
 397         rcu_read_lock();
 398         psock = sk_psock(sk);
 399         if (psock) {
 400                 if (sk->sk_prot->recvmsg != tcp_bpf_recvmsg) {
 401                         psock = ERR_PTR(-EBUSY);
 402                         goto out;
 403                 }
 404
 405                 if (!refcount_inc_not_zero(&psock->refcnt))
 406                         psock = ERR_PTR(-EBUSY);
 407         }
 408 out:
 409         rcu_read_unlock();
 410         return psock;
 411 }
 412
 413 static inline struct sk_psock *sk_psock_get(struct sock *sk)
 414 {
 415         struct sk_psock *psock;
 416
 417         rcu_read_lock();
 418         psock = sk_psock(sk);
 419         if (psock && !refcount_inc_not_zero(&psock->refcnt))
 420                 psock = NULL;
 421         rcu_read_unlock();
 422         return psock;
 423 }
 424
 425 void sk_psock_stop(struct sock *sk, struct sk_psock *psock);
 426 void sk_psock_destroy(struct rcu_head *rcu);
 427 void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
 428
 429 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
 430 {
 431         if (refcount_dec_and_test(&psock->refcnt))
 432                 sk_psock_drop(sk, psock);
 433 }
 434
 435 static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)
 436 {
 437         if (psock->parser.enabled)
 438                 psock->parser.saved_data_ready(sk);
 439         else
 440                 sk->sk_data_ready(sk);
 441 }
 442
 443 static inline void psock_set_prog(struct bpf_prog **pprog,
 444                                   struct bpf_prog *prog)
 445 {
 446         prog = xchg(pprog, prog);
 447         if (prog)
 448                 bpf_prog_put(prog);
 449 }
 450
 451 static inline void psock_progs_drop(struct sk_psock_progs *progs)
 452 {
 453         psock_set_prog(&progs->msg_parser, NULL);
 454         psock_set_prog(&progs->skb_parser, NULL);
 455         psock_set_prog(&progs->skb_verdict, NULL);
 456 }
 457
 458 #endif /* _LINUX_SKMSG_H */