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         bool                            copy[MAX_MSG_FRAGS];
  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
  39 /* UAPI in filter.c depends on struct sk_msg_sg being first element. */
  40 struct sk_msg {
  41         struct sk_msg_sg                sg;
  42         void                            *data;
  43         void                            *data_end;
  44         u32                             apply_bytes;
  45         u32                             cork_bytes;
  46         u32                             flags;
  47         struct sk_buff                  *skb;
  48         struct sock                     *sk_redir;
  49         struct sock                     *sk;
  50         struct list_head                list;
  51 };
  52
  53 struct sk_psock_progs {
  54         struct bpf_prog                 *msg_parser;
  55         struct bpf_prog                 *skb_parser;
  56         struct bpf_prog                 *skb_verdict;
  57 };
  58
  59 enum sk_psock_state_bits {
  60         SK_PSOCK_TX_ENABLED,
  61 };
  62
  63 struct sk_psock_link {
  64         struct list_head                list;
  65         struct bpf_map                  *map;
  66         void                            *link_raw;
  67 };
  68
  69 struct sk_psock_parser {
  70         struct strparser                strp;
  71         bool                            enabled;
  72         void (*saved_data_ready)(struct sock *sk);
  73 };
  74
  75 struct sk_psock_work_state {
  76         struct sk_buff                  *skb;
  77         u32                             len;
  78         u32                             off;
  79 };
  80
  81 struct sk_psock {
  82         struct sock                     *sk;
  83         struct sock                     *sk_redir;
  84         u32                             apply_bytes;
  85         u32                             cork_bytes;
  86         u32                             eval;
  87         struct sk_msg                   *cork;
  88         struct sk_psock_progs           progs;
  89         struct sk_psock_parser          parser;
  90         struct sk_buff_head             ingress_skb;
  91         struct list_head                ingress_msg;
  92         unsigned long                   state;
  93         struct list_head                link;
  94         spinlock_t                      link_lock;
  95         refcount_t                      refcnt;
  96         void (*saved_unhash)(struct sock *sk);
  97         void (*saved_close)(struct sock *sk, long timeout);
  98         void (*saved_write_space)(struct sock *sk);
  99         struct proto                    *sk_proto;
 100         struct sk_psock_work_state      work_state;
 101         struct work_struct              work;
 102         union {
 103                 struct rcu_head         rcu;
 104                 struct work_struct      gc;
 105         };
 106 };
 107
 108 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
 109                  int elem_first_coalesce);
 110 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
 111                  u32 off, u32 len);
 112 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len);
 113 int sk_msg_free(struct sock *sk, struct sk_msg *msg);
 114 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg);
 115 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes);
 116 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
 117                                   u32 bytes);
 118
 119 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes);
 120 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes);
 121
 122 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
 123                               struct sk_msg *msg, u32 bytes);
 124 int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
 125                              struct sk_msg *msg, u32 bytes);
 126
 127 static inline void sk_msg_check_to_free(struct sk_msg *msg, u32 i, u32 bytes)
 128 {
 129         WARN_ON(i == msg->sg.end && bytes);
 130 }
 131
 132 static inline void sk_msg_apply_bytes(struct sk_psock *psock, u32 bytes)
 133 {
 134         if (psock->apply_bytes) {
 135                 if (psock->apply_bytes < bytes)
 136                         psock->apply_bytes = 0;
 137                 else
 138                         psock->apply_bytes -= bytes;
 139         }
 140 }
 141
 142 static inline u32 sk_msg_iter_dist(u32 start, u32 end)
 143 {
 144         return end >= start ? end - start : end + (MAX_MSG_FRAGS - start);
 145 }
 146
 147 #define sk_msg_iter_var_prev(var)                       \
 148         do {                                            \
 149                 if (var == 0)                           \
 150                         var = MAX_MSG_FRAGS - 1;        \
 151                 else                                    \
 152                         var--;                          \
 153         } while (0)
 154
 155 #define sk_msg_iter_var_next(var)                       \
 156         do {                                            \
 157                 var++;                                  \
 158                 if (var == MAX_MSG_FRAGS)               \
 159                         var = 0;                        \
 160         } while (0)
 161
 162 #define sk_msg_iter_prev(msg, which)                    \
 163         sk_msg_iter_var_prev(msg->sg.which)
 164
 165 #define sk_msg_iter_next(msg, which)                    \
 166         sk_msg_iter_var_next(msg->sg.which)
 167
 168 static inline void sk_msg_clear_meta(struct sk_msg *msg)
 169 {
 170         memset(&msg->sg, 0, offsetofend(struct sk_msg_sg, copy));
 171 }
 172
 173 static inline void sk_msg_init(struct sk_msg *msg)
 174 {
 175         BUILD_BUG_ON(ARRAY_SIZE(msg->sg.data) - 1 != MAX_MSG_FRAGS);
 176         memset(msg, 0, sizeof(*msg));
 177         sg_init_marker(msg->sg.data, MAX_MSG_FRAGS);
 178 }
 179
 180 static inline void sk_msg_xfer(struct sk_msg *dst, struct sk_msg *src,
 181                                int which, u32 size)
 182 {
 183         dst->sg.data[which] = src->sg.data[which];
 184         dst->sg.data[which].length  = size;
 185         dst->sg.size               += size;
 186         src->sg.data[which].length -= size;
 187         src->sg.data[which].offset += size;
 188 }
 189
 190 static inline void sk_msg_xfer_full(struct sk_msg *dst, struct sk_msg *src)
 191 {
 192         memcpy(dst, src, sizeof(*src));
 193         sk_msg_init(src);
 194 }
 195
 196 static inline bool sk_msg_full(const struct sk_msg *msg)
 197 {
 198         return (msg->sg.end == msg->sg.start) && msg->sg.size;
 199 }
 200
 201 static inline u32 sk_msg_elem_used(const struct sk_msg *msg)
 202 {
 203         if (sk_msg_full(msg))
 204                 return MAX_MSG_FRAGS;
 205
 206         return sk_msg_iter_dist(msg->sg.start, msg->sg.end);
 207 }
 208
 209 static inline struct scatterlist *sk_msg_elem(struct sk_msg *msg, int which)
 210 {
 211         return &msg->sg.data[which];
 212 }
 213
 214 static inline struct scatterlist sk_msg_elem_cpy(struct sk_msg *msg, int which)
 215 {
 216         return msg->sg.data[which];
 217 }
 218
 219 static inline struct page *sk_msg_page(struct sk_msg *msg, int which)
 220 {
 221         return sg_page(sk_msg_elem(msg, which));
 222 }
 223
 224 static inline bool sk_msg_to_ingress(const struct sk_msg *msg)
 225 {
 226         return msg->flags & BPF_F_INGRESS;
 227 }
 228
 229 static inline void sk_msg_compute_data_pointers(struct sk_msg *msg)
 230 {
 231         struct scatterlist *sge = sk_msg_elem(msg, msg->sg.start);
 232
 233         if (msg->sg.copy[msg->sg.start]) {
 234                 msg->data = NULL;
 235                 msg->data_end = NULL;
 236         } else {
 237                 msg->data = sg_virt(sge);
 238                 msg->data_end = msg->data + sge->length;
 239         }
 240 }
 241
 242 static inline void sk_msg_page_add(struct sk_msg *msg, struct page *page,
 243                                    u32 len, u32 offset)
 244 {
 245         struct scatterlist *sge;
 246
 247         get_page(page);
 248         sge = sk_msg_elem(msg, msg->sg.end);
 249         sg_set_page(sge, page, len, offset);
 250         sg_unmark_end(sge);
 251
 252         msg->sg.copy[msg->sg.end] = true;
 253         msg->sg.size += len;
 254         sk_msg_iter_next(msg, end);
 255 }
 256
 257 static inline void sk_msg_sg_copy(struct sk_msg *msg, u32 i, bool copy_state)
 258 {
 259         do {
 260                 msg->sg.copy[i] = copy_state;
 261                 sk_msg_iter_var_next(i);
 262                 if (i == msg->sg.end)
 263                         break;
 264         } while (1);
 265 }
 266
 267 static inline void sk_msg_sg_copy_set(struct sk_msg *msg, u32 start)
 268 {
 269         sk_msg_sg_copy(msg, start, true);
 270 }
 271
 272 static inline void sk_msg_sg_copy_clear(struct sk_msg *msg, u32 start)
 273 {
 274         sk_msg_sg_copy(msg, start, false);
 275 }
 276
 277 static inline struct sk_psock *sk_psock(const struct sock *sk)
 278 {
 279         return rcu_dereference_sk_user_data(sk);
 280 }
 281
 282 static inline void sk_psock_queue_msg(struct sk_psock *psock,
 283                                       struct sk_msg *msg)
 284 {
 285         list_add_tail(&msg->list, &psock->ingress_msg);
 286 }
 287
 288 static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
 289 {
 290         return psock ? list_empty(&psock->ingress_msg) : true;
 291 }
 292
 293 static inline void sk_psock_report_error(struct sk_psock *psock, int err)
 294 {
 295         struct sock *sk = psock->sk;
 296
 297         sk->sk_err = err;
 298         sk->sk_error_report(sk);
 299 }
 300
 301 struct sk_psock *sk_psock_init(struct sock *sk, int node);
 302
 303 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
 304 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
 305 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
 306
 307 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
 308                          struct sk_msg *msg);
 309
 310 static inline struct sk_psock_link *sk_psock_init_link(void)
 311 {
 312         return kzalloc(sizeof(struct sk_psock_link),
 313                        GFP_ATOMIC | __GFP_NOWARN);
 314 }
 315
 316 static inline void sk_psock_free_link(struct sk_psock_link *link)
 317 {
 318         kfree(link);
 319 }
 320
 321 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock);
 322 #if defined(CONFIG_BPF_STREAM_PARSER)
 323 void sk_psock_unlink(struct sock *sk, struct sk_psock_link *link);
 324 #else
 325 static inline void sk_psock_unlink(struct sock *sk,
 326                                    struct sk_psock_link *link)
 327 {
 328 }
 329 #endif
 330
 331 void __sk_psock_purge_ingress_msg(struct sk_psock *psock);
 332
 333 static inline void sk_psock_cork_free(struct sk_psock *psock)
 334 {
 335         if (psock->cork) {
 336                 sk_msg_free(psock->sk, psock->cork);
 337                 kfree(psock->cork);
 338                 psock->cork = NULL;
 339         }
 340 }
 341
 342 static inline void sk_psock_update_proto(struct sock *sk,
 343                                          struct sk_psock *psock,
 344                                          struct proto *ops)
 345 {
 346         psock->saved_unhash = sk->sk_prot->unhash;
 347         psock->saved_close = sk->sk_prot->close;
 348         psock->saved_write_space = sk->sk_write_space;
 349
 350         psock->sk_proto = sk->sk_prot;
 351         sk->sk_prot = ops;
 352 }
 353
 354 static inline void sk_psock_restore_proto(struct sock *sk,
 355                                           struct sk_psock *psock)
 356 {
 357         sk->sk_write_space = psock->saved_write_space;
 358
 359         if (psock->sk_proto) {
 360                 struct inet_connection_sock *icsk = inet_csk(sk);
 361                 bool has_ulp = !!icsk->icsk_ulp_data;
 362
 363                 if (has_ulp)
 364                         tcp_update_ulp(sk, psock->sk_proto);
 365                 else
 366                         sk->sk_prot = psock->sk_proto;
 367                 psock->sk_proto = NULL;
 368         }
 369 }
 370
 371 static inline void sk_psock_set_state(struct sk_psock *psock,
 372                                       enum sk_psock_state_bits bit)
 373 {
 374         set_bit(bit, &psock->state);
 375 }
 376
 377 static inline void sk_psock_clear_state(struct sk_psock *psock,
 378                                         enum sk_psock_state_bits bit)
 379 {
 380         clear_bit(bit, &psock->state);
 381 }
 382
 383 static inline bool sk_psock_test_state(const struct sk_psock *psock,
 384                                        enum sk_psock_state_bits bit)
 385 {
 386         return test_bit(bit, &psock->state);
 387 }
 388
 389 static inline struct sk_psock *sk_psock_get_checked(struct sock *sk)
 390 {
 391         struct sk_psock *psock;
 392
 393         rcu_read_lock();
 394         psock = sk_psock(sk);
 395         if (psock) {
 396                 if (sk->sk_prot->recvmsg != tcp_bpf_recvmsg) {
 397                         psock = ERR_PTR(-EBUSY);
 398                         goto out;
 399                 }
 400
 401                 if (!refcount_inc_not_zero(&psock->refcnt))
 402                         psock = ERR_PTR(-EBUSY);
 403         }
 404 out:
 405         rcu_read_unlock();
 406         return psock;
 407 }
 408
 409 static inline struct sk_psock *sk_psock_get(struct sock *sk)
 410 {
 411         struct sk_psock *psock;
 412
 413         rcu_read_lock();
 414         psock = sk_psock(sk);
 415         if (psock && !refcount_inc_not_zero(&psock->refcnt))
 416                 psock = NULL;
 417         rcu_read_unlock();
 418         return psock;
 419 }
 420
 421 void sk_psock_stop(struct sock *sk, struct sk_psock *psock);
 422 void sk_psock_destroy(struct rcu_head *rcu);
 423 void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
 424
 425 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
 426 {
 427         if (refcount_dec_and_test(&psock->refcnt))
 428                 sk_psock_drop(sk, psock);
 429 }
 430
 431 static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)
 432 {
 433         if (psock->parser.enabled)
 434                 psock->parser.saved_data_ready(sk);
 435         else
 436                 sk->sk_data_ready(sk);
 437 }
 438
 439 static inline void psock_set_prog(struct bpf_prog **pprog,
 440                                   struct bpf_prog *prog)
 441 {
 442         prog = xchg(pprog, prog);
 443         if (prog)
 444                 bpf_prog_put(prog);
 445 }
 446
 447 static inline void psock_progs_drop(struct sk_psock_progs *progs)
 448 {
 449         psock_set_prog(&progs->msg_parser, NULL);
 450         psock_set_prog(&progs->skb_parser, NULL);
 451         psock_set_prog(&progs->skb_verdict, NULL);
 452 }
 453
 454 #endif /* _LINUX_SKMSG_H */