xref: /openbmc/linux/include/linux/skmsg.h (revision 377602fc) 
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 	SK_PSOCK_RX_STRP_ENABLED,
66 };
67 
68 struct sk_psock_link {
69 	struct list_head		list;
70 	struct bpf_map			*map;
71 	void				*link_raw;
72 };
73 
74 struct sk_psock_work_state {
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 	bool				redir_ingress; /* undefined if sk_redir is null */
86 	struct sk_msg			*cork;
87 	struct sk_psock_progs		progs;
88 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
89 	struct strparser		strp;
90 #endif
91 	struct sk_buff_head		ingress_skb;
92 	struct list_head		ingress_msg;
93 	spinlock_t			ingress_lock;
94 	unsigned long			state;
95 	struct list_head		link;
96 	spinlock_t			link_lock;
97 	refcount_t			refcnt;
98 	void (*saved_unhash)(struct sock *sk);
99 	void (*saved_destroy)(struct sock *sk);
100 	void (*saved_close)(struct sock *sk, long timeout);
101 	void (*saved_write_space)(struct sock *sk);
102 	void (*saved_data_ready)(struct sock *sk);
103 	int  (*psock_update_sk_prot)(struct sock *sk, struct sk_psock *psock,
104 				     bool restore);
105 	struct proto			*sk_proto;
106 	struct mutex			work_mutex;
107 	struct sk_psock_work_state	work_state;
108 	struct delayed_work		work;
109 	struct sock			*sk_pair;
110 	struct rcu_work			rwork;
111 };
112 
113 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
114 		 int elem_first_coalesce);
115 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
116 		 u32 off, u32 len);
117 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len);
118 int sk_msg_free(struct sock *sk, struct sk_msg *msg);
119 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg);
120 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes);
121 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
122 				  u32 bytes);
123 
124 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes);
125 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes);
126 
127 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
128 			      struct sk_msg *msg, u32 bytes);
129 int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
130 			     struct sk_msg *msg, u32 bytes);
131 int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
132 		   int len, int flags);
133 bool sk_msg_is_readable(struct sock *sk);
134 
135 static inline void sk_msg_check_to_free(struct sk_msg *msg, u32 i, u32 bytes)
136 {
137 	WARN_ON(i == msg->sg.end && bytes);
138 }
139 
140 static inline void sk_msg_apply_bytes(struct sk_psock *psock, u32 bytes)
141 {
142 	if (psock->apply_bytes) {
143 		if (psock->apply_bytes < bytes)
144 			psock->apply_bytes = 0;
145 		else
146 			psock->apply_bytes -= bytes;
147 	}
148 }
149 
150 static inline u32 sk_msg_iter_dist(u32 start, u32 end)
151 {
152 	return end >= start ? end - start : end + (NR_MSG_FRAG_IDS - start);
153 }
154 
155 #define sk_msg_iter_var_prev(var)			\
156 	do {						\
157 		if (var == 0)				\
158 			var = NR_MSG_FRAG_IDS - 1;	\
159 		else					\
160 			var--;				\
161 	} while (0)
162 
163 #define sk_msg_iter_var_next(var)			\
164 	do {						\
165 		var++;					\
166 		if (var == NR_MSG_FRAG_IDS)		\
167 			var = 0;			\
168 	} while (0)
169 
170 #define sk_msg_iter_prev(msg, which)			\
171 	sk_msg_iter_var_prev(msg->sg.which)
172 
173 #define sk_msg_iter_next(msg, which)			\
174 	sk_msg_iter_var_next(msg->sg.which)
175 
176 static inline void sk_msg_init(struct sk_msg *msg)
177 {
178 	BUILD_BUG_ON(ARRAY_SIZE(msg->sg.data) - 1 != NR_MSG_FRAG_IDS);
179 	memset(msg, 0, sizeof(*msg));
180 	sg_init_marker(msg->sg.data, NR_MSG_FRAG_IDS);
181 }
182 
183 static inline void sk_msg_xfer(struct sk_msg *dst, struct sk_msg *src,
184 			       int which, u32 size)
185 {
186 	dst->sg.data[which] = src->sg.data[which];
187 	dst->sg.data[which].length  = size;
188 	dst->sg.size		   += size;
189 	src->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_with_flags(sk,
284 							 SK_USER_DATA_PSOCK);
285 }
286 
287 static inline void sk_psock_set_state(struct sk_psock *psock,
288 				      enum sk_psock_state_bits bit)
289 {
290 	set_bit(bit, &psock->state);
291 }
292 
293 static inline void sk_psock_clear_state(struct sk_psock *psock,
294 					enum sk_psock_state_bits bit)
295 {
296 	clear_bit(bit, &psock->state);
297 }
298 
299 static inline bool sk_psock_test_state(const struct sk_psock *psock,
300 				       enum sk_psock_state_bits bit)
301 {
302 	return test_bit(bit, &psock->state);
303 }
304 
305 static inline void sock_drop(struct sock *sk, struct sk_buff *skb)
306 {
307 	sk_drops_add(sk, skb);
308 	kfree_skb(skb);
309 }
310 
311 static inline void sk_psock_queue_msg(struct sk_psock *psock,
312 				      struct sk_msg *msg)
313 {
314 	spin_lock_bh(&psock->ingress_lock);
315 	if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
316 		list_add_tail(&msg->list, &psock->ingress_msg);
317 	else {
318 		sk_msg_free(psock->sk, msg);
319 		kfree(msg);
320 	}
321 	spin_unlock_bh(&psock->ingress_lock);
322 }
323 
324 static inline struct sk_msg *sk_psock_dequeue_msg(struct sk_psock *psock)
325 {
326 	struct sk_msg *msg;
327 
328 	spin_lock_bh(&psock->ingress_lock);
329 	msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
330 	if (msg)
331 		list_del(&msg->list);
332 	spin_unlock_bh(&psock->ingress_lock);
333 	return msg;
334 }
335 
336 static inline struct sk_msg *sk_psock_peek_msg(struct sk_psock *psock)
337 {
338 	struct sk_msg *msg;
339 
340 	spin_lock_bh(&psock->ingress_lock);
341 	msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
342 	spin_unlock_bh(&psock->ingress_lock);
343 	return msg;
344 }
345 
346 static inline struct sk_msg *sk_psock_next_msg(struct sk_psock *psock,
347 					       struct sk_msg *msg)
348 {
349 	struct sk_msg *ret;
350 
351 	spin_lock_bh(&psock->ingress_lock);
352 	if (list_is_last(&msg->list, &psock->ingress_msg))
353 		ret = NULL;
354 	else
355 		ret = list_next_entry(msg, list);
356 	spin_unlock_bh(&psock->ingress_lock);
357 	return ret;
358 }
359 
360 static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
361 {
362 	return psock ? list_empty(&psock->ingress_msg) : true;
363 }
364 
365 static inline void kfree_sk_msg(struct sk_msg *msg)
366 {
367 	if (msg->skb)
368 		consume_skb(msg->skb);
369 	kfree(msg);
370 }
371 
372 static inline void sk_psock_report_error(struct sk_psock *psock, int err)
373 {
374 	struct sock *sk = psock->sk;
375 
376 	sk->sk_err = err;
377 	sk_error_report(sk);
378 }
379 
380 struct sk_psock *sk_psock_init(struct sock *sk, int node);
381 void sk_psock_stop(struct sk_psock *psock);
382 
383 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
384 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
385 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
386 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
387 #else
388 static inline int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
389 {
390 	return -EOPNOTSUPP;
391 }
392 
393 static inline void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
394 {
395 }
396 
397 static inline void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
398 {
399 }
400 #endif
401 
402 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock);
403 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock);
404 
405 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
406 			 struct sk_msg *msg);
407 
408 static inline struct sk_psock_link *sk_psock_init_link(void)
409 {
410 	return kzalloc(sizeof(struct sk_psock_link),
411 		       GFP_ATOMIC | __GFP_NOWARN);
412 }
413 
414 static inline void sk_psock_free_link(struct sk_psock_link *link)
415 {
416 	kfree(link);
417 }
418 
419 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock);
420 
421 static inline void sk_psock_cork_free(struct sk_psock *psock)
422 {
423 	if (psock->cork) {
424 		sk_msg_free(psock->sk, psock->cork);
425 		kfree(psock->cork);
426 		psock->cork = NULL;
427 	}
428 }
429 
430 static inline void sk_psock_restore_proto(struct sock *sk,
431 					  struct sk_psock *psock)
432 {
433 	if (psock->psock_update_sk_prot)
434 		psock->psock_update_sk_prot(sk, psock, true);
435 }
436 
437 static inline struct sk_psock *sk_psock_get(struct sock *sk)
438 {
439 	struct sk_psock *psock;
440 
441 	rcu_read_lock();
442 	psock = sk_psock(sk);
443 	if (psock && !refcount_inc_not_zero(&psock->refcnt))
444 		psock = NULL;
445 	rcu_read_unlock();
446 	return psock;
447 }
448 
449 void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
450 
451 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
452 {
453 	if (refcount_dec_and_test(&psock->refcnt))
454 		sk_psock_drop(sk, psock);
455 }
456 
457 static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)
458 {
459 	if (psock->saved_data_ready)
460 		psock->saved_data_ready(sk);
461 	else
462 		sk->sk_data_ready(sk);
463 }
464 
465 static inline void psock_set_prog(struct bpf_prog **pprog,
466 				  struct bpf_prog *prog)
467 {
468 	prog = xchg(pprog, prog);
469 	if (prog)
470 		bpf_prog_put(prog);
471 }
472 
473 static inline int psock_replace_prog(struct bpf_prog **pprog,
474 				     struct bpf_prog *prog,
475 				     struct bpf_prog *old)
476 {
477 	if (cmpxchg(pprog, old, prog) != old)
478 		return -ENOENT;
479 
480 	if (old)
481 		bpf_prog_put(old);
482 
483 	return 0;
484 }
485 
486 static inline void psock_progs_drop(struct sk_psock_progs *progs)
487 {
488 	psock_set_prog(&progs->msg_parser, NULL);
489 	psock_set_prog(&progs->stream_parser, NULL);
490 	psock_set_prog(&progs->stream_verdict, NULL);
491 	psock_set_prog(&progs->skb_verdict, NULL);
492 }
493 
494 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb);
495 
496 static inline bool sk_psock_strp_enabled(struct sk_psock *psock)
497 {
498 	if (!psock)
499 		return false;
500 	return !!psock->saved_data_ready;
501 }
502 
503 #if IS_ENABLED(CONFIG_NET_SOCK_MSG)
504 
505 #define BPF_F_STRPARSER	(1UL << 1)
506 
507 /* We only have two bits so far. */
508 #define BPF_F_PTR_MASK ~(BPF_F_INGRESS | BPF_F_STRPARSER)
509 
510 static inline bool skb_bpf_strparser(const struct sk_buff *skb)
511 {
512 	unsigned long sk_redir = skb->_sk_redir;
513 
514 	return sk_redir & BPF_F_STRPARSER;
515 }
516 
517 static inline void skb_bpf_set_strparser(struct sk_buff *skb)
518 {
519 	skb->_sk_redir |= BPF_F_STRPARSER;
520 }
521 
522 static inline bool skb_bpf_ingress(const struct sk_buff *skb)
523 {
524 	unsigned long sk_redir = skb->_sk_redir;
525 
526 	return sk_redir & BPF_F_INGRESS;
527 }
528 
529 static inline void skb_bpf_set_ingress(struct sk_buff *skb)
530 {
531 	skb->_sk_redir |= BPF_F_INGRESS;
532 }
533 
534 static inline void skb_bpf_set_redir(struct sk_buff *skb, struct sock *sk_redir,
535 				     bool ingress)
536 {
537 	skb->_sk_redir = (unsigned long)sk_redir;
538 	if (ingress)
539 		skb->_sk_redir |= BPF_F_INGRESS;
540 }
541 
542 static inline struct sock *skb_bpf_redirect_fetch(const struct sk_buff *skb)
543 {
544 	unsigned long sk_redir = skb->_sk_redir;
545 
546 	return (struct sock *)(sk_redir & BPF_F_PTR_MASK);
547 }
548 
549 static inline void skb_bpf_redirect_clear(struct sk_buff *skb)
550 {
551 	skb->_sk_redir = 0;
552 }
553 #endif /* CONFIG_NET_SOCK_MSG */
554 #endif /* _LINUX_SKMSG_H */
555