xref: /linux/include/linux/skmsg.h (revision 07fdad3a93756b872da7b53647715c48d0f4a2d0) 
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 	DECLARE_BITMAP(copy, MAX_MSG_FRAGS + 2);
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 
42 /* UAPI in filter.c depends on struct sk_msg_sg being first element. */
43 struct sk_msg {
44 	struct sk_msg_sg		sg;
45 	void				*data;
46 	void				*data_end;
47 	u32				apply_bytes;
48 	u32				cork_bytes;
49 	u32				flags;
50 	struct sk_buff			*skb;
51 	struct sock			*sk_redir;
52 	struct sock			*sk;
53 	struct list_head		list;
54 };
55 
56 struct sk_psock_progs {
57 	struct bpf_prog			*msg_parser;
58 	struct bpf_prog			*stream_parser;
59 	struct bpf_prog			*stream_verdict;
60 	struct bpf_prog			*skb_verdict;
61 	struct bpf_link			*msg_parser_link;
62 	struct bpf_link			*stream_parser_link;
63 	struct bpf_link			*stream_verdict_link;
64 	struct bpf_link			*skb_verdict_link;
65 };
66 
67 enum sk_psock_state_bits {
68 	SK_PSOCK_TX_ENABLED,
69 	SK_PSOCK_RX_STRP_ENABLED,
70 };
71 
72 struct sk_psock_link {
73 	struct list_head		list;
74 	struct bpf_map			*map;
75 	void				*link_raw;
76 };
77 
78 struct sk_psock_work_state {
79 	u32				len;
80 	u32				off;
81 };
82 
83 struct sk_psock {
84 	struct sock			*sk;
85 	struct sock			*sk_redir;
86 	u32				apply_bytes;
87 	u32				cork_bytes;
88 	u32				eval;
89 	bool				redir_ingress; /* undefined if sk_redir is null */
90 	struct sk_msg			*cork;
91 	struct sk_psock_progs		progs;
92 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
93 	struct strparser		strp;
94 	u32				copied_seq;
95 	u32				ingress_bytes;
96 #endif
97 	struct sk_buff_head		ingress_skb;
98 	struct list_head		ingress_msg;
99 	spinlock_t			ingress_lock;
100 	unsigned long			state;
101 	struct list_head		link;
102 	spinlock_t			link_lock;
103 	refcount_t			refcnt;
104 	void (*saved_unhash)(struct sock *sk);
105 	void (*saved_destroy)(struct sock *sk);
106 	void (*saved_close)(struct sock *sk, long timeout);
107 	void (*saved_write_space)(struct sock *sk);
108 	void (*saved_data_ready)(struct sock *sk);
109 	/* psock_update_sk_prot may be called with restore=false many times
110 	 * so the handler must be safe for this case. It will be called
111 	 * exactly once with restore=true when the psock is being destroyed
112 	 * and psock refcnt is zero, but before an RCU grace period.
113 	 */
114 	int  (*psock_update_sk_prot)(struct sock *sk, struct sk_psock *psock,
115 				     bool restore);
116 	struct proto			*sk_proto;
117 	struct mutex			work_mutex;
118 	struct sk_psock_work_state	work_state;
119 	struct delayed_work		work;
120 	struct sock			*sk_pair;
121 	struct rcu_work			rwork;
122 };
123 
124 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
125 		 int elem_first_coalesce);
126 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
127 		 u32 off, u32 len);
128 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len);
129 int sk_msg_free(struct sock *sk, struct sk_msg *msg);
130 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg);
131 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes);
132 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
133 				  u32 bytes);
134 
135 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes);
136 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes);
137 
138 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
139 			      struct sk_msg *msg, u32 bytes);
140 int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
141 			     struct sk_msg *msg, u32 bytes);
142 int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
143 		   int len, int flags);
144 bool sk_msg_is_readable(struct sock *sk);
145 
146 static inline void sk_msg_check_to_free(struct sk_msg *msg, u32 i, u32 bytes)
147 {
148 	WARN_ON(i == msg->sg.end && bytes);
149 }
150 
151 static inline void sk_msg_apply_bytes(struct sk_psock *psock, u32 bytes)
152 {
153 	if (psock->apply_bytes) {
154 		if (psock->apply_bytes < bytes)
155 			psock->apply_bytes = 0;
156 		else
157 			psock->apply_bytes -= bytes;
158 	}
159 }
160 
161 static inline u32 sk_msg_iter_dist(u32 start, u32 end)
162 {
163 	return end >= start ? end - start : end + (NR_MSG_FRAG_IDS - start);
164 }
165 
166 #define sk_msg_iter_var_prev(var)			\
167 	do {						\
168 		if (var == 0)				\
169 			var = NR_MSG_FRAG_IDS - 1;	\
170 		else					\
171 			var--;				\
172 	} while (0)
173 
174 #define sk_msg_iter_var_next(var)			\
175 	do {						\
176 		var++;					\
177 		if (var == NR_MSG_FRAG_IDS)		\
178 			var = 0;			\
179 	} while (0)
180 
181 #define sk_msg_iter_prev(msg, which)			\
182 	sk_msg_iter_var_prev(msg->sg.which)
183 
184 #define sk_msg_iter_next(msg, which)			\
185 	sk_msg_iter_var_next(msg->sg.which)
186 
187 static inline void sk_msg_init(struct sk_msg *msg)
188 {
189 	BUILD_BUG_ON(ARRAY_SIZE(msg->sg.data) - 1 != NR_MSG_FRAG_IDS);
190 	memset(msg, 0, sizeof(*msg));
191 	sg_init_marker(msg->sg.data, NR_MSG_FRAG_IDS);
192 }
193 
194 static inline void sk_msg_xfer(struct sk_msg *dst, struct sk_msg *src,
195 			       int which, u32 size)
196 {
197 	dst->sg.data[which] = src->sg.data[which];
198 	dst->sg.data[which].length  = size;
199 	dst->sg.size		   += size;
200 	src->sg.size		   -= size;
201 	src->sg.data[which].length -= size;
202 	src->sg.data[which].offset += size;
203 }
204 
205 static inline void sk_msg_xfer_full(struct sk_msg *dst, struct sk_msg *src)
206 {
207 	memcpy(dst, src, sizeof(*src));
208 	sk_msg_init(src);
209 }
210 
211 static inline bool sk_msg_full(const struct sk_msg *msg)
212 {
213 	return sk_msg_iter_dist(msg->sg.start, msg->sg.end) == MAX_MSG_FRAGS;
214 }
215 
216 static inline u32 sk_msg_elem_used(const struct sk_msg *msg)
217 {
218 	return sk_msg_iter_dist(msg->sg.start, msg->sg.end);
219 }
220 
221 static inline struct scatterlist *sk_msg_elem(struct sk_msg *msg, int which)
222 {
223 	return &msg->sg.data[which];
224 }
225 
226 static inline struct scatterlist sk_msg_elem_cpy(struct sk_msg *msg, int which)
227 {
228 	return msg->sg.data[which];
229 }
230 
231 static inline struct page *sk_msg_page(struct sk_msg *msg, int which)
232 {
233 	return sg_page(sk_msg_elem(msg, which));
234 }
235 
236 static inline bool sk_msg_to_ingress(const struct sk_msg *msg)
237 {
238 	return msg->flags & BPF_F_INGRESS;
239 }
240 
241 static inline void sk_msg_compute_data_pointers(struct sk_msg *msg)
242 {
243 	struct scatterlist *sge = sk_msg_elem(msg, msg->sg.start);
244 
245 	if (test_bit(msg->sg.start, msg->sg.copy)) {
246 		msg->data = NULL;
247 		msg->data_end = NULL;
248 	} else {
249 		msg->data = sg_virt(sge);
250 		msg->data_end = msg->data + sge->length;
251 	}
252 }
253 
254 static inline void sk_msg_page_add(struct sk_msg *msg, struct page *page,
255 				   u32 len, u32 offset)
256 {
257 	struct scatterlist *sge;
258 
259 	get_page(page);
260 	sge = sk_msg_elem(msg, msg->sg.end);
261 	sg_set_page(sge, page, len, offset);
262 	sg_unmark_end(sge);
263 
264 	__set_bit(msg->sg.end, msg->sg.copy);
265 	msg->sg.size += len;
266 	sk_msg_iter_next(msg, end);
267 }
268 
269 static inline void sk_msg_sg_copy(struct sk_msg *msg, u32 i, bool copy_state)
270 {
271 	do {
272 		if (copy_state)
273 			__set_bit(i, msg->sg.copy);
274 		else
275 			__clear_bit(i, msg->sg.copy);
276 		sk_msg_iter_var_next(i);
277 		if (i == msg->sg.end)
278 			break;
279 	} while (1);
280 }
281 
282 static inline void sk_msg_sg_copy_set(struct sk_msg *msg, u32 start)
283 {
284 	sk_msg_sg_copy(msg, start, true);
285 }
286 
287 static inline void sk_msg_sg_copy_clear(struct sk_msg *msg, u32 start)
288 {
289 	sk_msg_sg_copy(msg, start, false);
290 }
291 
292 static inline struct sk_psock *sk_psock(const struct sock *sk)
293 {
294 	return __rcu_dereference_sk_user_data_with_flags(sk,
295 							 SK_USER_DATA_PSOCK);
296 }
297 
298 static inline void sk_psock_set_state(struct sk_psock *psock,
299 				      enum sk_psock_state_bits bit)
300 {
301 	set_bit(bit, &psock->state);
302 }
303 
304 static inline void sk_psock_clear_state(struct sk_psock *psock,
305 					enum sk_psock_state_bits bit)
306 {
307 	clear_bit(bit, &psock->state);
308 }
309 
310 static inline bool sk_psock_test_state(const struct sk_psock *psock,
311 				       enum sk_psock_state_bits bit)
312 {
313 	return test_bit(bit, &psock->state);
314 }
315 
316 static inline void sock_drop(struct sock *sk, struct sk_buff *skb)
317 {
318 	sk_drops_skbadd(sk, skb);
319 	kfree_skb(skb);
320 }
321 
322 static inline bool sk_psock_queue_msg(struct sk_psock *psock,
323 				      struct sk_msg *msg)
324 {
325 	bool ret;
326 
327 	spin_lock_bh(&psock->ingress_lock);
328 	if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
329 		list_add_tail(&msg->list, &psock->ingress_msg);
330 		ret = true;
331 	} else {
332 		sk_msg_free(psock->sk, msg);
333 		kfree(msg);
334 		ret = false;
335 	}
336 	spin_unlock_bh(&psock->ingress_lock);
337 	return ret;
338 }
339 
340 static inline struct sk_msg *sk_psock_dequeue_msg(struct sk_psock *psock)
341 {
342 	struct sk_msg *msg;
343 
344 	spin_lock_bh(&psock->ingress_lock);
345 	msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
346 	if (msg)
347 		list_del(&msg->list);
348 	spin_unlock_bh(&psock->ingress_lock);
349 	return msg;
350 }
351 
352 static inline struct sk_msg *sk_psock_peek_msg(struct sk_psock *psock)
353 {
354 	struct sk_msg *msg;
355 
356 	spin_lock_bh(&psock->ingress_lock);
357 	msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
358 	spin_unlock_bh(&psock->ingress_lock);
359 	return msg;
360 }
361 
362 static inline struct sk_msg *sk_psock_next_msg(struct sk_psock *psock,
363 					       struct sk_msg *msg)
364 {
365 	struct sk_msg *ret;
366 
367 	spin_lock_bh(&psock->ingress_lock);
368 	if (list_is_last(&msg->list, &psock->ingress_msg))
369 		ret = NULL;
370 	else
371 		ret = list_next_entry(msg, list);
372 	spin_unlock_bh(&psock->ingress_lock);
373 	return ret;
374 }
375 
376 static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
377 {
378 	return psock ? list_empty(&psock->ingress_msg) : true;
379 }
380 
381 static inline void kfree_sk_msg(struct sk_msg *msg)
382 {
383 	if (msg->skb)
384 		consume_skb(msg->skb);
385 	kfree(msg);
386 }
387 
388 static inline void sk_psock_report_error(struct sk_psock *psock, int err)
389 {
390 	struct sock *sk = psock->sk;
391 
392 	sk->sk_err = err;
393 	sk_error_report(sk);
394 }
395 
396 struct sk_psock *sk_psock_init(struct sock *sk, int node);
397 void sk_psock_stop(struct sk_psock *psock);
398 
399 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
400 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
401 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
402 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
403 #else
404 static inline int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
405 {
406 	return -EOPNOTSUPP;
407 }
408 
409 static inline void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
410 {
411 }
412 
413 static inline void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
414 {
415 }
416 #endif
417 
418 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock);
419 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock);
420 
421 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
422 			 struct sk_msg *msg);
423 
424 /*
425  * This specialized allocator has to be a macro for its allocations to be
426  * accounted separately (to have a separate alloc_tag). The typecast is
427  * intentional to enforce typesafety.
428  */
429 #define sk_psock_init_link()	\
430 		((struct sk_psock_link *)kzalloc(sizeof(struct sk_psock_link),	\
431 						 GFP_ATOMIC | __GFP_NOWARN))
432 
433 static inline void sk_psock_free_link(struct sk_psock_link *link)
434 {
435 	kfree(link);
436 }
437 
438 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock);
439 
440 static inline void sk_psock_cork_free(struct sk_psock *psock)
441 {
442 	if (psock->cork) {
443 		sk_msg_free(psock->sk, psock->cork);
444 		kfree(psock->cork);
445 		psock->cork = NULL;
446 	}
447 }
448 
449 static inline void sk_psock_restore_proto(struct sock *sk,
450 					  struct sk_psock *psock)
451 {
452 	if (psock->psock_update_sk_prot)
453 		psock->psock_update_sk_prot(sk, psock, true);
454 }
455 
456 static inline struct sk_psock *sk_psock_get(struct sock *sk)
457 {
458 	struct sk_psock *psock;
459 
460 	rcu_read_lock();
461 	psock = sk_psock(sk);
462 	if (psock && !refcount_inc_not_zero(&psock->refcnt))
463 		psock = NULL;
464 	rcu_read_unlock();
465 	return psock;
466 }
467 
468 void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
469 
470 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
471 {
472 	if (refcount_dec_and_test(&psock->refcnt))
473 		sk_psock_drop(sk, psock);
474 }
475 
476 static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)
477 {
478 	read_lock_bh(&sk->sk_callback_lock);
479 	if (psock->saved_data_ready)
480 		psock->saved_data_ready(sk);
481 	else
482 		sk->sk_data_ready(sk);
483 	read_unlock_bh(&sk->sk_callback_lock);
484 }
485 
486 static inline void psock_set_prog(struct bpf_prog **pprog,
487 				  struct bpf_prog *prog)
488 {
489 	prog = xchg(pprog, prog);
490 	if (prog)
491 		bpf_prog_put(prog);
492 }
493 
494 static inline int psock_replace_prog(struct bpf_prog **pprog,
495 				     struct bpf_prog *prog,
496 				     struct bpf_prog *old)
497 {
498 	if (cmpxchg(pprog, old, prog) != old)
499 		return -ENOENT;
500 
501 	if (old)
502 		bpf_prog_put(old);
503 
504 	return 0;
505 }
506 
507 static inline void psock_progs_drop(struct sk_psock_progs *progs)
508 {
509 	psock_set_prog(&progs->msg_parser, NULL);
510 	psock_set_prog(&progs->stream_parser, NULL);
511 	psock_set_prog(&progs->stream_verdict, NULL);
512 	psock_set_prog(&progs->skb_verdict, NULL);
513 }
514 
515 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb);
516 
517 static inline bool sk_psock_strp_enabled(struct sk_psock *psock)
518 {
519 	if (!psock)
520 		return false;
521 	return !!psock->saved_data_ready;
522 }
523 
524 #if IS_ENABLED(CONFIG_NET_SOCK_MSG)
525 
526 #define BPF_F_STRPARSER	(1UL << 1)
527 
528 /* We only have two bits so far. */
529 #define BPF_F_PTR_MASK ~(BPF_F_INGRESS | BPF_F_STRPARSER)
530 
531 static inline bool skb_bpf_strparser(const struct sk_buff *skb)
532 {
533 	unsigned long sk_redir = skb->_sk_redir;
534 
535 	return sk_redir & BPF_F_STRPARSER;
536 }
537 
538 static inline void skb_bpf_set_strparser(struct sk_buff *skb)
539 {
540 	skb->_sk_redir |= BPF_F_STRPARSER;
541 }
542 
543 static inline bool skb_bpf_ingress(const struct sk_buff *skb)
544 {
545 	unsigned long sk_redir = skb->_sk_redir;
546 
547 	return sk_redir & BPF_F_INGRESS;
548 }
549 
550 static inline void skb_bpf_set_ingress(struct sk_buff *skb)
551 {
552 	skb->_sk_redir |= BPF_F_INGRESS;
553 }
554 
555 static inline void skb_bpf_set_redir(struct sk_buff *skb, struct sock *sk_redir,
556 				     bool ingress)
557 {
558 	skb->_sk_redir = (unsigned long)sk_redir;
559 	if (ingress)
560 		skb->_sk_redir |= BPF_F_INGRESS;
561 }
562 
563 static inline struct sock *skb_bpf_redirect_fetch(const struct sk_buff *skb)
564 {
565 	unsigned long sk_redir = skb->_sk_redir;
566 
567 	return (struct sock *)(sk_redir & BPF_F_PTR_MASK);
568 }
569 
570 static inline void skb_bpf_redirect_clear(struct sk_buff *skb)
571 {
572 	skb->_sk_redir = 0;
573 }
574 #endif /* CONFIG_NET_SOCK_MSG */
575 #endif /* _LINUX_SKMSG_H */
576