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 *skb_parser; 60 struct bpf_prog *skb_verdict; 61 }; 62 63 enum sk_psock_state_bits { 64 SK_PSOCK_TX_ENABLED, 65 }; 66 67 struct sk_psock_link { 68 struct list_head list; 69 struct bpf_map *map; 70 void *link_raw; 71 }; 72 73 struct sk_psock_parser { 74 struct strparser strp; 75 bool enabled; 76 void (*saved_data_ready)(struct sock *sk); 77 }; 78 79 struct sk_psock_work_state { 80 struct sk_buff *skb; 81 u32 len; 82 u32 off; 83 }; 84 85 struct sk_psock { 86 struct sock *sk; 87 struct sock *sk_redir; 88 u32 apply_bytes; 89 u32 cork_bytes; 90 u32 eval; 91 struct sk_msg *cork; 92 struct sk_psock_progs progs; 93 struct sk_psock_parser parser; 94 struct sk_buff_head ingress_skb; 95 struct list_head ingress_msg; 96 unsigned long state; 97 struct list_head link; 98 spinlock_t link_lock; 99 refcount_t refcnt; 100 void (*saved_unhash)(struct sock *sk); 101 void (*saved_close)(struct sock *sk, long timeout); 102 void (*saved_write_space)(struct sock *sk); 103 struct proto *sk_proto; 104 struct sk_psock_work_state work_state; 105 struct work_struct work; 106 union { 107 struct rcu_head rcu; 108 struct work_struct gc; 109 }; 110 }; 111 112 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len, 113 int elem_first_coalesce); 114 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src, 115 u32 off, u32 len); 116 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len); 117 int sk_msg_free(struct sock *sk, struct sk_msg *msg); 118 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg); 119 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes); 120 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg, 121 u32 bytes); 122 123 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes); 124 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes); 125 126 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from, 127 struct sk_msg *msg, u32 bytes); 128 int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from, 129 struct sk_msg *msg, u32 bytes); 130 131 static inline void sk_msg_check_to_free(struct sk_msg *msg, u32 i, u32 bytes) 132 { 133 WARN_ON(i == msg->sg.end && bytes); 134 } 135 136 static inline void sk_msg_apply_bytes(struct sk_psock *psock, u32 bytes) 137 { 138 if (psock->apply_bytes) { 139 if (psock->apply_bytes < bytes) 140 psock->apply_bytes = 0; 141 else 142 psock->apply_bytes -= bytes; 143 } 144 } 145 146 static inline u32 sk_msg_iter_dist(u32 start, u32 end) 147 { 148 return end >= start ? end - start : end + (NR_MSG_FRAG_IDS - start); 149 } 150 151 #define sk_msg_iter_var_prev(var) \ 152 do { \ 153 if (var == 0) \ 154 var = NR_MSG_FRAG_IDS - 1; \ 155 else \ 156 var--; \ 157 } while (0) 158 159 #define sk_msg_iter_var_next(var) \ 160 do { \ 161 var++; \ 162 if (var == NR_MSG_FRAG_IDS) \ 163 var = 0; \ 164 } while (0) 165 166 #define sk_msg_iter_prev(msg, which) \ 167 sk_msg_iter_var_prev(msg->sg.which) 168 169 #define sk_msg_iter_next(msg, which) \ 170 sk_msg_iter_var_next(msg->sg.which) 171 172 static inline void sk_msg_clear_meta(struct sk_msg *msg) 173 { 174 memset(&msg->sg, 0, offsetofend(struct sk_msg_sg, copy)); 175 } 176 177 static inline void sk_msg_init(struct sk_msg *msg) 178 { 179 BUILD_BUG_ON(ARRAY_SIZE(msg->sg.data) - 1 != NR_MSG_FRAG_IDS); 180 memset(msg, 0, sizeof(*msg)); 181 sg_init_marker(msg->sg.data, NR_MSG_FRAG_IDS); 182 } 183 184 static inline void sk_msg_xfer(struct sk_msg *dst, struct sk_msg *src, 185 int which, u32 size) 186 { 187 dst->sg.data[which] = src->sg.data[which]; 188 dst->sg.data[which].length = size; 189 dst->sg.size += size; 190 src->sg.data[which].length -= size; 191 src->sg.data[which].offset += size; 192 } 193 194 static inline void sk_msg_xfer_full(struct sk_msg *dst, struct sk_msg *src) 195 { 196 memcpy(dst, src, sizeof(*src)); 197 sk_msg_init(src); 198 } 199 200 static inline bool sk_msg_full(const struct sk_msg *msg) 201 { 202 return sk_msg_iter_dist(msg->sg.start, msg->sg.end) == MAX_MSG_FRAGS; 203 } 204 205 static inline u32 sk_msg_elem_used(const struct sk_msg *msg) 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_prot->unhash = psock->saved_unhash; 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 psock->saved_write_space); 370 } else { 371 sk->sk_prot = psock->sk_proto; 372 sk->sk_write_space = psock->saved_write_space; 373 } 374 psock->sk_proto = NULL; 375 } else { 376 sk->sk_write_space = psock->saved_write_space; 377 } 378 } 379 380 static inline void sk_psock_set_state(struct sk_psock *psock, 381 enum sk_psock_state_bits bit) 382 { 383 set_bit(bit, &psock->state); 384 } 385 386 static inline void sk_psock_clear_state(struct sk_psock *psock, 387 enum sk_psock_state_bits bit) 388 { 389 clear_bit(bit, &psock->state); 390 } 391 392 static inline bool sk_psock_test_state(const struct sk_psock *psock, 393 enum sk_psock_state_bits bit) 394 { 395 return test_bit(bit, &psock->state); 396 } 397 398 static inline struct sk_psock *sk_psock_get_checked(struct sock *sk) 399 { 400 struct sk_psock *psock; 401 402 rcu_read_lock(); 403 psock = sk_psock(sk); 404 if (psock) { 405 if (sk->sk_prot->recvmsg != tcp_bpf_recvmsg) { 406 psock = ERR_PTR(-EBUSY); 407 goto out; 408 } 409 410 if (!refcount_inc_not_zero(&psock->refcnt)) 411 psock = ERR_PTR(-EBUSY); 412 } 413 out: 414 rcu_read_unlock(); 415 return psock; 416 } 417 418 static inline struct sk_psock *sk_psock_get(struct sock *sk) 419 { 420 struct sk_psock *psock; 421 422 rcu_read_lock(); 423 psock = sk_psock(sk); 424 if (psock && !refcount_inc_not_zero(&psock->refcnt)) 425 psock = NULL; 426 rcu_read_unlock(); 427 return psock; 428 } 429 430 void sk_psock_stop(struct sock *sk, struct sk_psock *psock); 431 void sk_psock_destroy(struct rcu_head *rcu); 432 void sk_psock_drop(struct sock *sk, struct sk_psock *psock); 433 434 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock) 435 { 436 if (refcount_dec_and_test(&psock->refcnt)) 437 sk_psock_drop(sk, psock); 438 } 439 440 static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock) 441 { 442 if (psock->parser.enabled) 443 psock->parser.saved_data_ready(sk); 444 else 445 sk->sk_data_ready(sk); 446 } 447 448 static inline void psock_set_prog(struct bpf_prog **pprog, 449 struct bpf_prog *prog) 450 { 451 prog = xchg(pprog, prog); 452 if (prog) 453 bpf_prog_put(prog); 454 } 455 456 static inline void psock_progs_drop(struct sk_psock_progs *progs) 457 { 458 psock_set_prog(&progs->msg_parser, NULL); 459 psock_set_prog(&progs->skb_parser, NULL); 460 psock_set_prog(&progs->skb_verdict, NULL); 461 } 462 463 #endif /* _LINUX_SKMSG_H */ 464