xref: /linux-6.15/include/linux/skmsg.h (revision b8cd5831) 
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 drop_sk_msg(struct sk_psock *psock, struct sk_msg *msg)
308 {
309 	if (msg->skb)
310 		sock_drop(psock->sk, msg->skb);
311 	kfree(msg);
312 }
313 
314 static inline void sk_psock_queue_msg(struct sk_psock *psock,
315 				      struct sk_msg *msg)
316 {
317 	spin_lock_bh(&psock->ingress_lock);
318 	if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
319 		list_add_tail(&msg->list, &psock->ingress_msg);
320 	else
321 		drop_sk_msg(psock, msg);
322 	spin_unlock_bh(&psock->ingress_lock);
323 }
324 
325 static inline struct sk_msg *sk_psock_dequeue_msg(struct sk_psock *psock)
326 {
327 	struct sk_msg *msg;
328 
329 	spin_lock_bh(&psock->ingress_lock);
330 	msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
331 	if (msg)
332 		list_del(&msg->list);
333 	spin_unlock_bh(&psock->ingress_lock);
334 	return msg;
335 }
336 
337 static inline struct sk_msg *sk_psock_peek_msg(struct sk_psock *psock)
338 {
339 	struct sk_msg *msg;
340 
341 	spin_lock_bh(&psock->ingress_lock);
342 	msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
343 	spin_unlock_bh(&psock->ingress_lock);
344 	return msg;
345 }
346 
347 static inline struct sk_msg *sk_psock_next_msg(struct sk_psock *psock,
348 					       struct sk_msg *msg)
349 {
350 	struct sk_msg *ret;
351 
352 	spin_lock_bh(&psock->ingress_lock);
353 	if (list_is_last(&msg->list, &psock->ingress_msg))
354 		ret = NULL;
355 	else
356 		ret = list_next_entry(msg, list);
357 	spin_unlock_bh(&psock->ingress_lock);
358 	return ret;
359 }
360 
361 static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
362 {
363 	return psock ? list_empty(&psock->ingress_msg) : true;
364 }
365 
366 static inline void kfree_sk_msg(struct sk_msg *msg)
367 {
368 	if (msg->skb)
369 		consume_skb(msg->skb);
370 	kfree(msg);
371 }
372 
373 static inline void sk_psock_report_error(struct sk_psock *psock, int err)
374 {
375 	struct sock *sk = psock->sk;
376 
377 	sk->sk_err = err;
378 	sk_error_report(sk);
379 }
380 
381 struct sk_psock *sk_psock_init(struct sock *sk, int node);
382 void sk_psock_stop(struct sk_psock *psock, bool wait);
383 
384 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
385 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
386 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
387 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
388 #else
389 static inline int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
390 {
391 	return -EOPNOTSUPP;
392 }
393 
394 static inline void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
395 {
396 }
397 
398 static inline void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
399 {
400 }
401 #endif
402 
403 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock);
404 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock);
405 
406 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
407 			 struct sk_msg *msg);
408 
409 static inline struct sk_psock_link *sk_psock_init_link(void)
410 {
411 	return kzalloc(sizeof(struct sk_psock_link),
412 		       GFP_ATOMIC | __GFP_NOWARN);
413 }
414 
415 static inline void sk_psock_free_link(struct sk_psock_link *link)
416 {
417 	kfree(link);
418 }
419 
420 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock);
421 
422 static inline void sk_psock_cork_free(struct sk_psock *psock)
423 {
424 	if (psock->cork) {
425 		sk_msg_free(psock->sk, psock->cork);
426 		kfree(psock->cork);
427 		psock->cork = NULL;
428 	}
429 }
430 
431 static inline void sk_psock_restore_proto(struct sock *sk,
432 					  struct sk_psock *psock)
433 {
434 	if (psock->psock_update_sk_prot)
435 		psock->psock_update_sk_prot(sk, psock, true);
436 }
437 
438 static inline struct sk_psock *sk_psock_get(struct sock *sk)
439 {
440 	struct sk_psock *psock;
441 
442 	rcu_read_lock();
443 	psock = sk_psock(sk);
444 	if (psock && !refcount_inc_not_zero(&psock->refcnt))
445 		psock = NULL;
446 	rcu_read_unlock();
447 	return psock;
448 }
449 
450 void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
451 
452 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
453 {
454 	if (refcount_dec_and_test(&psock->refcnt))
455 		sk_psock_drop(sk, psock);
456 }
457 
458 static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)
459 {
460 	if (psock->saved_data_ready)
461 		psock->saved_data_ready(sk);
462 	else
463 		sk->sk_data_ready(sk);
464 }
465 
466 static inline void psock_set_prog(struct bpf_prog **pprog,
467 				  struct bpf_prog *prog)
468 {
469 	prog = xchg(pprog, prog);
470 	if (prog)
471 		bpf_prog_put(prog);
472 }
473 
474 static inline int psock_replace_prog(struct bpf_prog **pprog,
475 				     struct bpf_prog *prog,
476 				     struct bpf_prog *old)
477 {
478 	if (cmpxchg(pprog, old, prog) != old)
479 		return -ENOENT;
480 
481 	if (old)
482 		bpf_prog_put(old);
483 
484 	return 0;
485 }
486 
487 static inline void psock_progs_drop(struct sk_psock_progs *progs)
488 {
489 	psock_set_prog(&progs->msg_parser, NULL);
490 	psock_set_prog(&progs->stream_parser, NULL);
491 	psock_set_prog(&progs->stream_verdict, NULL);
492 	psock_set_prog(&progs->skb_verdict, NULL);
493 }
494 
495 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb);
496 
497 static inline bool sk_psock_strp_enabled(struct sk_psock *psock)
498 {
499 	if (!psock)
500 		return false;
501 	return !!psock->saved_data_ready;
502 }
503 
504 static inline bool sk_is_udp(const struct sock *sk)
505 {
506 	return sk->sk_type == SOCK_DGRAM &&
507 	       sk->sk_protocol == IPPROTO_UDP;
508 }
509 
510 #if IS_ENABLED(CONFIG_NET_SOCK_MSG)
511 
512 #define BPF_F_STRPARSER	(1UL << 1)
513 
514 /* We only have two bits so far. */
515 #define BPF_F_PTR_MASK ~(BPF_F_INGRESS | BPF_F_STRPARSER)
516 
517 static inline bool skb_bpf_strparser(const struct sk_buff *skb)
518 {
519 	unsigned long sk_redir = skb->_sk_redir;
520 
521 	return sk_redir & BPF_F_STRPARSER;
522 }
523 
524 static inline void skb_bpf_set_strparser(struct sk_buff *skb)
525 {
526 	skb->_sk_redir |= BPF_F_STRPARSER;
527 }
528 
529 static inline bool skb_bpf_ingress(const struct sk_buff *skb)
530 {
531 	unsigned long sk_redir = skb->_sk_redir;
532 
533 	return sk_redir & BPF_F_INGRESS;
534 }
535 
536 static inline void skb_bpf_set_ingress(struct sk_buff *skb)
537 {
538 	skb->_sk_redir |= BPF_F_INGRESS;
539 }
540 
541 static inline void skb_bpf_set_redir(struct sk_buff *skb, struct sock *sk_redir,
542 				     bool ingress)
543 {
544 	skb->_sk_redir = (unsigned long)sk_redir;
545 	if (ingress)
546 		skb->_sk_redir |= BPF_F_INGRESS;
547 }
548 
549 static inline struct sock *skb_bpf_redirect_fetch(const struct sk_buff *skb)
550 {
551 	unsigned long sk_redir = skb->_sk_redir;
552 
553 	return (struct sock *)(sk_redir & BPF_F_PTR_MASK);
554 }
555 
556 static inline void skb_bpf_redirect_clear(struct sk_buff *skb)
557 {
558 	skb->_sk_redir = 0;
559 }
560 #endif /* CONFIG_NET_SOCK_MSG */
561 #endif /* _LINUX_SKMSG_H */
562