xref: /linux/include/linux/skmsg.h (revision b83deaa741558babf4b8d51d34f6637ccfff1b26) 
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 };
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_work_state {
74 	struct sk_buff			*skb;
75 	u32				len;
76 	u32				off;
77 };
78 
79 struct sk_psock {
80 	struct sock			*sk;
81 	struct sock			*sk_redir;
82 	u32				apply_bytes;
83 	u32				cork_bytes;
84 	u32				eval;
85 	struct sk_msg			*cork;
86 	struct sk_psock_progs		progs;
87 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
88 	struct strparser		strp;
89 #endif
90 	struct sk_buff_head		ingress_skb;
91 	struct list_head		ingress_msg;
92 	spinlock_t			ingress_lock;
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 	void (*saved_data_ready)(struct sock *sk);
101 	int  (*psock_update_sk_prot)(struct sock *sk, struct sk_psock *psock,
102 				     bool restore);
103 	struct proto			*sk_proto;
104 	struct mutex			work_mutex;
105 	struct sk_psock_work_state	work_state;
106 	struct work_struct		work;
107 	struct rcu_work			rwork;
108 };
109 
110 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
111 		 int elem_first_coalesce);
112 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
113 		 u32 off, u32 len);
114 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len);
115 int sk_msg_free(struct sock *sk, struct sk_msg *msg);
116 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg);
117 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes);
118 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
119 				  u32 bytes);
120 
121 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes);
122 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes);
123 
124 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
125 			      struct sk_msg *msg, u32 bytes);
126 int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
127 			     struct sk_msg *msg, u32 bytes);
128 int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
129 		   int len, int flags);
130 bool sk_msg_is_readable(struct sock *sk);
131 
132 static inline void sk_msg_check_to_free(struct sk_msg *msg, u32 i, u32 bytes)
133 {
134 	WARN_ON(i == msg->sg.end && bytes);
135 }
136 
137 static inline void sk_msg_apply_bytes(struct sk_psock *psock, u32 bytes)
138 {
139 	if (psock->apply_bytes) {
140 		if (psock->apply_bytes < bytes)
141 			psock->apply_bytes = 0;
142 		else
143 			psock->apply_bytes -= bytes;
144 	}
145 }
146 
147 static inline u32 sk_msg_iter_dist(u32 start, u32 end)
148 {
149 	return end >= start ? end - start : end + (NR_MSG_FRAG_IDS - start);
150 }
151 
152 #define sk_msg_iter_var_prev(var)			\
153 	do {						\
154 		if (var == 0)				\
155 			var = NR_MSG_FRAG_IDS - 1;	\
156 		else					\
157 			var--;				\
158 	} while (0)
159 
160 #define sk_msg_iter_var_next(var)			\
161 	do {						\
162 		var++;					\
163 		if (var == NR_MSG_FRAG_IDS)		\
164 			var = 0;			\
165 	} while (0)
166 
167 #define sk_msg_iter_prev(msg, which)			\
168 	sk_msg_iter_var_prev(msg->sg.which)
169 
170 #define sk_msg_iter_next(msg, which)			\
171 	sk_msg_iter_var_next(msg->sg.which)
172 
173 static inline void sk_msg_init(struct sk_msg *msg)
174 {
175 	BUILD_BUG_ON(ARRAY_SIZE(msg->sg.data) - 1 != NR_MSG_FRAG_IDS);
176 	memset(msg, 0, sizeof(*msg));
177 	sg_init_marker(msg->sg.data, NR_MSG_FRAG_IDS);
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.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 sk_msg_iter_dist(msg->sg.start, msg->sg.end) == MAX_MSG_FRAGS;
200 }
201 
202 static inline u32 sk_msg_elem_used(const struct sk_msg *msg)
203 {
204 	return sk_msg_iter_dist(msg->sg.start, msg->sg.end);
205 }
206 
207 static inline struct scatterlist *sk_msg_elem(struct sk_msg *msg, int which)
208 {
209 	return &msg->sg.data[which];
210 }
211 
212 static inline struct scatterlist sk_msg_elem_cpy(struct sk_msg *msg, int which)
213 {
214 	return msg->sg.data[which];
215 }
216 
217 static inline struct page *sk_msg_page(struct sk_msg *msg, int which)
218 {
219 	return sg_page(sk_msg_elem(msg, which));
220 }
221 
222 static inline bool sk_msg_to_ingress(const struct sk_msg *msg)
223 {
224 	return msg->flags & BPF_F_INGRESS;
225 }
226 
227 static inline void sk_msg_compute_data_pointers(struct sk_msg *msg)
228 {
229 	struct scatterlist *sge = sk_msg_elem(msg, msg->sg.start);
230 
231 	if (test_bit(msg->sg.start, msg->sg.copy)) {
232 		msg->data = NULL;
233 		msg->data_end = NULL;
234 	} else {
235 		msg->data = sg_virt(sge);
236 		msg->data_end = msg->data + sge->length;
237 	}
238 }
239 
240 static inline void sk_msg_page_add(struct sk_msg *msg, struct page *page,
241 				   u32 len, u32 offset)
242 {
243 	struct scatterlist *sge;
244 
245 	get_page(page);
246 	sge = sk_msg_elem(msg, msg->sg.end);
247 	sg_set_page(sge, page, len, offset);
248 	sg_unmark_end(sge);
249 
250 	__set_bit(msg->sg.end, msg->sg.copy);
251 	msg->sg.size += len;
252 	sk_msg_iter_next(msg, end);
253 }
254 
255 static inline void sk_msg_sg_copy(struct sk_msg *msg, u32 i, bool copy_state)
256 {
257 	do {
258 		if (copy_state)
259 			__set_bit(i, msg->sg.copy);
260 		else
261 			__clear_bit(i, msg->sg.copy);
262 		sk_msg_iter_var_next(i);
263 		if (i == msg->sg.end)
264 			break;
265 	} while (1);
266 }
267 
268 static inline void sk_msg_sg_copy_set(struct sk_msg *msg, u32 start)
269 {
270 	sk_msg_sg_copy(msg, start, true);
271 }
272 
273 static inline void sk_msg_sg_copy_clear(struct sk_msg *msg, u32 start)
274 {
275 	sk_msg_sg_copy(msg, start, false);
276 }
277 
278 static inline struct sk_psock *sk_psock(const struct sock *sk)
279 {
280 	return rcu_dereference_sk_user_data(sk);
281 }
282 
283 static inline void sk_psock_set_state(struct sk_psock *psock,
284 				      enum sk_psock_state_bits bit)
285 {
286 	set_bit(bit, &psock->state);
287 }
288 
289 static inline void sk_psock_clear_state(struct sk_psock *psock,
290 					enum sk_psock_state_bits bit)
291 {
292 	clear_bit(bit, &psock->state);
293 }
294 
295 static inline bool sk_psock_test_state(const struct sk_psock *psock,
296 				       enum sk_psock_state_bits bit)
297 {
298 	return test_bit(bit, &psock->state);
299 }
300 
301 static inline void sock_drop(struct sock *sk, struct sk_buff *skb)
302 {
303 	sk_drops_add(sk, skb);
304 	kfree_skb(skb);
305 }
306 
307 static inline void sk_psock_queue_msg(struct sk_psock *psock,
308 				      struct sk_msg *msg)
309 {
310 	spin_lock_bh(&psock->ingress_lock);
311 	if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
312 		list_add_tail(&msg->list, &psock->ingress_msg);
313 	else {
314 		sk_msg_free(psock->sk, msg);
315 		kfree(msg);
316 	}
317 	spin_unlock_bh(&psock->ingress_lock);
318 }
319 
320 static inline struct sk_msg *sk_psock_dequeue_msg(struct sk_psock *psock)
321 {
322 	struct sk_msg *msg;
323 
324 	spin_lock_bh(&psock->ingress_lock);
325 	msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
326 	if (msg)
327 		list_del(&msg->list);
328 	spin_unlock_bh(&psock->ingress_lock);
329 	return msg;
330 }
331 
332 static inline struct sk_msg *sk_psock_peek_msg(struct sk_psock *psock)
333 {
334 	struct sk_msg *msg;
335 
336 	spin_lock_bh(&psock->ingress_lock);
337 	msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
338 	spin_unlock_bh(&psock->ingress_lock);
339 	return msg;
340 }
341 
342 static inline struct sk_msg *sk_psock_next_msg(struct sk_psock *psock,
343 					       struct sk_msg *msg)
344 {
345 	struct sk_msg *ret;
346 
347 	spin_lock_bh(&psock->ingress_lock);
348 	if (list_is_last(&msg->list, &psock->ingress_msg))
349 		ret = NULL;
350 	else
351 		ret = list_next_entry(msg, list);
352 	spin_unlock_bh(&psock->ingress_lock);
353 	return ret;
354 }
355 
356 static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
357 {
358 	return psock ? list_empty(&psock->ingress_msg) : true;
359 }
360 
361 static inline void kfree_sk_msg(struct sk_msg *msg)
362 {
363 	if (msg->skb)
364 		consume_skb(msg->skb);
365 	kfree(msg);
366 }
367 
368 static inline void sk_psock_report_error(struct sk_psock *psock, int err)
369 {
370 	struct sock *sk = psock->sk;
371 
372 	sk->sk_err = err;
373 	sk_error_report(sk);
374 }
375 
376 struct sk_psock *sk_psock_init(struct sock *sk, int node);
377 void sk_psock_stop(struct sk_psock *psock, bool wait);
378 
379 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
380 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
381 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
382 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
383 #else
384 static inline int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
385 {
386 	return -EOPNOTSUPP;
387 }
388 
389 static inline void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
390 {
391 }
392 
393 static inline void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
394 {
395 }
396 #endif
397 
398 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock);
399 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock);
400 
401 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
402 			 struct sk_msg *msg);
403 
404 static inline struct sk_psock_link *sk_psock_init_link(void)
405 {
406 	return kzalloc(sizeof(struct sk_psock_link),
407 		       GFP_ATOMIC | __GFP_NOWARN);
408 }
409 
410 static inline void sk_psock_free_link(struct sk_psock_link *link)
411 {
412 	kfree(link);
413 }
414 
415 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock);
416 
417 static inline void sk_psock_cork_free(struct sk_psock *psock)
418 {
419 	if (psock->cork) {
420 		sk_msg_free(psock->sk, psock->cork);
421 		kfree(psock->cork);
422 		psock->cork = NULL;
423 	}
424 }
425 
426 static inline void sk_psock_restore_proto(struct sock *sk,
427 					  struct sk_psock *psock)
428 {
429 	if (psock->psock_update_sk_prot)
430 		psock->psock_update_sk_prot(sk, psock, true);
431 }
432 
433 static inline struct sk_psock *sk_psock_get(struct sock *sk)
434 {
435 	struct sk_psock *psock;
436 
437 	rcu_read_lock();
438 	psock = sk_psock(sk);
439 	if (psock && !refcount_inc_not_zero(&psock->refcnt))
440 		psock = NULL;
441 	rcu_read_unlock();
442 	return psock;
443 }
444 
445 void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
446 
447 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
448 {
449 	if (refcount_dec_and_test(&psock->refcnt))
450 		sk_psock_drop(sk, psock);
451 }
452 
453 static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)
454 {
455 	if (psock->saved_data_ready)
456 		psock->saved_data_ready(sk);
457 	else
458 		sk->sk_data_ready(sk);
459 }
460 
461 static inline void psock_set_prog(struct bpf_prog **pprog,
462 				  struct bpf_prog *prog)
463 {
464 	prog = xchg(pprog, prog);
465 	if (prog)
466 		bpf_prog_put(prog);
467 }
468 
469 static inline int psock_replace_prog(struct bpf_prog **pprog,
470 				     struct bpf_prog *prog,
471 				     struct bpf_prog *old)
472 {
473 	if (cmpxchg(pprog, old, prog) != old)
474 		return -ENOENT;
475 
476 	if (old)
477 		bpf_prog_put(old);
478 
479 	return 0;
480 }
481 
482 static inline void psock_progs_drop(struct sk_psock_progs *progs)
483 {
484 	psock_set_prog(&progs->msg_parser, NULL);
485 	psock_set_prog(&progs->stream_parser, NULL);
486 	psock_set_prog(&progs->stream_verdict, NULL);
487 	psock_set_prog(&progs->skb_verdict, NULL);
488 }
489 
490 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb);
491 
492 static inline bool sk_psock_strp_enabled(struct sk_psock *psock)
493 {
494 	if (!psock)
495 		return false;
496 	return !!psock->saved_data_ready;
497 }
498 
499 static inline bool sk_is_udp(const struct sock *sk)
500 {
501 	return sk->sk_type == SOCK_DGRAM &&
502 	       sk->sk_protocol == IPPROTO_UDP;
503 }
504 
505 #if IS_ENABLED(CONFIG_NET_SOCK_MSG)
506 
507 #define BPF_F_STRPARSER	(1UL << 1)
508 
509 /* We only have two bits so far. */
510 #define BPF_F_PTR_MASK ~(BPF_F_INGRESS | BPF_F_STRPARSER)
511 
512 static inline bool skb_bpf_strparser(const struct sk_buff *skb)
513 {
514 	unsigned long sk_redir = skb->_sk_redir;
515 
516 	return sk_redir & BPF_F_STRPARSER;
517 }
518 
519 static inline void skb_bpf_set_strparser(struct sk_buff *skb)
520 {
521 	skb->_sk_redir |= BPF_F_STRPARSER;
522 }
523 
524 static inline bool skb_bpf_ingress(const struct sk_buff *skb)
525 {
526 	unsigned long sk_redir = skb->_sk_redir;
527 
528 	return sk_redir & BPF_F_INGRESS;
529 }
530 
531 static inline void skb_bpf_set_ingress(struct sk_buff *skb)
532 {
533 	skb->_sk_redir |= BPF_F_INGRESS;
534 }
535 
536 static inline void skb_bpf_set_redir(struct sk_buff *skb, struct sock *sk_redir,
537 				     bool ingress)
538 {
539 	skb->_sk_redir = (unsigned long)sk_redir;
540 	if (ingress)
541 		skb->_sk_redir |= BPF_F_INGRESS;
542 }
543 
544 static inline struct sock *skb_bpf_redirect_fetch(const struct sk_buff *skb)
545 {
546 	unsigned long sk_redir = skb->_sk_redir;
547 
548 	return (struct sock *)(sk_redir & BPF_F_PTR_MASK);
549 }
550 
551 static inline void skb_bpf_redirect_clear(struct sk_buff *skb)
552 {
553 	skb->_sk_redir = 0;
554 }
555 #endif /* CONFIG_NET_SOCK_MSG */
556 #endif /* _LINUX_SKMSG_H */
557