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 #define sk_msg_iter_var_prev(var)                       \
 143         do {                                            \
 144                 if (var == 0)                           \
 145                         var = MAX_MSG_FRAGS - 1;        \
 146                 else                                    \
 147                         var--;                          \
 148         } while (0)
 149
 150 #define sk_msg_iter_var_next(var)                       \
 151         do {                                            \
 152                 var++;                                  \
 153                 if (var == MAX_MSG_FRAGS)               \
 154                         var = 0;                        \
 155         } while (0)
 156
 157 #define sk_msg_iter_prev(msg, which)                    \
 158         sk_msg_iter_var_prev(msg->sg.which)
 159
 160 #define sk_msg_iter_next(msg, which)                    \
 161         sk_msg_iter_var_next(msg->sg.which)
 162
 163 static inline void sk_msg_clear_meta(struct sk_msg *msg)
 164 {
 165         memset(&msg->sg, 0, offsetofend(struct sk_msg_sg, copy));
 166 }
 167
 168 static inline void sk_msg_init(struct sk_msg *msg)
 169 {
 170         BUILD_BUG_ON(ARRAY_SIZE(msg->sg.data) - 1 != MAX_MSG_FRAGS);
 171         memset(msg, 0, sizeof(*msg));
 172         sg_init_marker(msg->sg.data, MAX_MSG_FRAGS);
 173 }
 174
 175 static inline void sk_msg_xfer(struct sk_msg *dst, struct sk_msg *src,
 176                                int which, u32 size)
 177 {
 178         dst->sg.data[which] = src->sg.data[which];
 179         dst->sg.data[which].length  = size;
 180         dst->sg.size               += size;
 181         src->sg.data[which].length -= size;
 182         src->sg.data[which].offset += size;
 183 }
 184
 185 static inline void sk_msg_xfer_full(struct sk_msg *dst, struct sk_msg *src)
 186 {
 187         memcpy(dst, src, sizeof(*src));
 188         sk_msg_init(src);
 189 }
 190
 191 static inline bool sk_msg_full(const struct sk_msg *msg)
 192 {
 193         return (msg->sg.end == msg->sg.start) && msg->sg.size;
 194 }
 195
 196 static inline u32 sk_msg_elem_used(const struct sk_msg *msg)
 197 {
 198         if (sk_msg_full(msg))
 199                 return MAX_MSG_FRAGS;
 200
 201         return msg->sg.end >= msg->sg.start ?
 202                 msg->sg.end - msg->sg.start :
 203                 msg->sg.end + (MAX_MSG_FRAGS - msg->sg.start);
 204 }
 205
 206 static inline struct scatterlist *sk_msg_elem(struct sk_msg *msg, int which)
 207 {
 208         return &msg->sg.data[which];
 209 }
 210
 211 static inline struct scatterlist sk_msg_elem_cpy(struct sk_msg *msg, int which)
 212 {
 213         return msg->sg.data[which];
 214 }
 215
 216 static inline struct page *sk_msg_page(struct sk_msg *msg, int which)
 217 {
 218         return sg_page(sk_msg_elem(msg, which));
 219 }
 220
 221 static inline bool sk_msg_to_ingress(const struct sk_msg *msg)
 222 {
 223         return msg->flags & BPF_F_INGRESS;
 224 }
 225
 226 static inline void sk_msg_compute_data_pointers(struct sk_msg *msg)
 227 {
 228         struct scatterlist *sge = sk_msg_elem(msg, msg->sg.start);
 229
 230         if (msg->sg.copy[msg->sg.start]) {
 231                 msg->data = NULL;
 232                 msg->data_end = NULL;
 233         } else {
 234                 msg->data = sg_virt(sge);
 235                 msg->data_end = msg->data + sge->length;
 236         }
 237 }
 238
 239 static inline void sk_msg_page_add(struct sk_msg *msg, struct page *page,
 240                                    u32 len, u32 offset)
 241 {
 242         struct scatterlist *sge;
 243
 244         get_page(page);
 245         sge = sk_msg_elem(msg, msg->sg.end);
 246         sg_set_page(sge, page, len, offset);
 247         sg_unmark_end(sge);
 248
 249         msg->sg.copy[msg->sg.end] = true;
 250         msg->sg.size += len;
 251         sk_msg_iter_next(msg, end);
 252 }
 253
 254 static inline void sk_msg_sg_copy(struct sk_msg *msg, u32 i, bool copy_state)
 255 {
 256         do {
 257                 msg->sg.copy[i] = copy_state;
 258                 sk_msg_iter_var_next(i);
 259                 if (i == msg->sg.end)
 260                         break;
 261         } while (1);
 262 }
 263
 264 static inline void sk_msg_sg_copy_set(struct sk_msg *msg, u32 start)
 265 {
 266         sk_msg_sg_copy(msg, start, true);
 267 }
 268
 269 static inline void sk_msg_sg_copy_clear(struct sk_msg *msg, u32 start)
 270 {
 271         sk_msg_sg_copy(msg, start, false);
 272 }
 273
 274 static inline struct sk_psock *sk_psock(const struct sock *sk)
 275 {
 276         return rcu_dereference_sk_user_data(sk);
 277 }
 278
 279 static inline void sk_psock_queue_msg(struct sk_psock *psock,
 280                                       struct sk_msg *msg)
 281 {
 282         list_add_tail(&msg->list, &psock->ingress_msg);
 283 }
 284
 285 static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
 286 {
 287         return psock ? list_empty(&psock->ingress_msg) : true;
 288 }
 289
 290 static inline void sk_psock_report_error(struct sk_psock *psock, int err)
 291 {
 292         struct sock *sk = psock->sk;
 293
 294         sk->sk_err = err;
 295         sk->sk_error_report(sk);
 296 }
 297
 298 struct sk_psock *sk_psock_init(struct sock *sk, int node);
 299
 300 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
 301 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
 302 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
 303
 304 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
 305                          struct sk_msg *msg);
 306
 307 static inline struct sk_psock_link *sk_psock_init_link(void)
 308 {
 309         return kzalloc(sizeof(struct sk_psock_link),
 310                        GFP_ATOMIC | __GFP_NOWARN);
 311 }
 312
 313 static inline void sk_psock_free_link(struct sk_psock_link *link)
 314 {
 315         kfree(link);
 316 }
 317
 318 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock);
 319 #if defined(CONFIG_BPF_STREAM_PARSER)
 320 void sk_psock_unlink(struct sock *sk, struct sk_psock_link *link);
 321 #else
 322 static inline void sk_psock_unlink(struct sock *sk,
 323                                    struct sk_psock_link *link)
 324 {
 325 }
 326 #endif
 327
 328 void __sk_psock_purge_ingress_msg(struct sk_psock *psock);
 329
 330 static inline void sk_psock_cork_free(struct sk_psock *psock)
 331 {
 332         if (psock->cork) {
 333                 sk_msg_free(psock->sk, psock->cork);
 334                 kfree(psock->cork);
 335                 psock->cork = NULL;
 336         }
 337 }
 338
 339 static inline void sk_psock_update_proto(struct sock *sk,
 340                                          struct sk_psock *psock,
 341                                          struct proto *ops)
 342 {
 343         psock->saved_unhash = sk->sk_prot->unhash;
 344         psock->saved_close = sk->sk_prot->close;
 345         psock->saved_write_space = sk->sk_write_space;
 346
 347         psock->sk_proto = sk->sk_prot;
 348         sk->sk_prot = ops;
 349 }
 350
 351 static inline void sk_psock_restore_proto(struct sock *sk,
 352                                           struct sk_psock *psock)
 353 {
 354         sk->sk_write_space = psock->saved_write_space;
 355
 356         if (psock->sk_proto) {
 357                 struct inet_connection_sock *icsk = inet_csk(sk);
 358                 bool has_ulp = !!icsk->icsk_ulp_data;
 359
 360                 if (has_ulp)
 361                         tcp_update_ulp(sk, psock->sk_proto);
 362                 else
 363                         sk->sk_prot = psock->sk_proto;
 364                 psock->sk_proto = NULL;
 365         }
 366 }
 367
 368 static inline void sk_psock_set_state(struct sk_psock *psock,
 369                                       enum sk_psock_state_bits bit)
 370 {
 371         set_bit(bit, &psock->state);
 372 }
 373
 374 static inline void sk_psock_clear_state(struct sk_psock *psock,
 375                                         enum sk_psock_state_bits bit)
 376 {
 377         clear_bit(bit, &psock->state);
 378 }
 379
 380 static inline bool sk_psock_test_state(const struct sk_psock *psock,
 381                                        enum sk_psock_state_bits bit)
 382 {
 383         return test_bit(bit, &psock->state);
 384 }
 385
 386 static inline struct sk_psock *sk_psock_get_checked(struct sock *sk)
 387 {
 388         struct sk_psock *psock;
 389
 390         rcu_read_lock();
 391         psock = sk_psock(sk);
 392         if (psock) {
 393                 if (sk->sk_prot->recvmsg != tcp_bpf_recvmsg) {
 394                         psock = ERR_PTR(-EBUSY);
 395                         goto out;
 396                 }
 397
 398                 if (!refcount_inc_not_zero(&psock->refcnt))
 399                         psock = ERR_PTR(-EBUSY);
 400         }
 401 out:
 402         rcu_read_unlock();
 403         return psock;
 404 }
 405
 406 static inline struct sk_psock *sk_psock_get(struct sock *sk)
 407 {
 408         struct sk_psock *psock;
 409
 410         rcu_read_lock();
 411         psock = sk_psock(sk);
 412         if (psock && !refcount_inc_not_zero(&psock->refcnt))
 413                 psock = NULL;
 414         rcu_read_unlock();
 415         return psock;
 416 }
 417
 418 void sk_psock_stop(struct sock *sk, struct sk_psock *psock);
 419 void sk_psock_destroy(struct rcu_head *rcu);
 420 void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
 421
 422 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
 423 {
 424         if (refcount_dec_and_test(&psock->refcnt))
 425                 sk_psock_drop(sk, psock);
 426 }
 427
 428 static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)
 429 {
 430         if (psock->parser.enabled)
 431                 psock->parser.saved_data_ready(sk);
 432         else
 433                 sk->sk_data_ready(sk);
 434 }
 435
 436 static inline void psock_set_prog(struct bpf_prog **pprog,
 437                                   struct bpf_prog *prog)
 438 {
 439         prog = xchg(pprog, prog);
 440         if (prog)
 441                 bpf_prog_put(prog);
 442 }
 443
 444 static inline void psock_progs_drop(struct sk_psock_progs *progs)
 445 {
 446         psock_set_prog(&progs->msg_parser, NULL);
 447         psock_set_prog(&progs->skb_parser, NULL);
 448         psock_set_prog(&progs->skb_verdict, NULL);
 449 }
 450
 451 #endif /* _LINUX_SKMSG_H */