xref: /linux-6.15/include/linux/skmsg.h (revision bb8e97e2) 
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 rcu_work			rwork;
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 int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
131 		   int len, int flags);
132 bool sk_msg_is_readable(struct sock *sk);
133 
134 static inline void sk_msg_check_to_free(struct sk_msg *msg, u32 i, u32 bytes)
135 {
136 	WARN_ON(i == msg->sg.end && bytes);
137 }
138 
139 static inline void sk_msg_apply_bytes(struct sk_psock *psock, u32 bytes)
140 {
141 	if (psock->apply_bytes) {
142 		if (psock->apply_bytes < bytes)
143 			psock->apply_bytes = 0;
144 		else
145 			psock->apply_bytes -= bytes;
146 	}
147 }
148 
149 static inline u32 sk_msg_iter_dist(u32 start, u32 end)
150 {
151 	return end >= start ? end - start : end + (NR_MSG_FRAG_IDS - start);
152 }
153 
154 #define sk_msg_iter_var_prev(var)			\
155 	do {						\
156 		if (var == 0)				\
157 			var = NR_MSG_FRAG_IDS - 1;	\
158 		else					\
159 			var--;				\
160 	} while (0)
161 
162 #define sk_msg_iter_var_next(var)			\
163 	do {						\
164 		var++;					\
165 		if (var == NR_MSG_FRAG_IDS)		\
166 			var = 0;			\
167 	} while (0)
168 
169 #define sk_msg_iter_prev(msg, which)			\
170 	sk_msg_iter_var_prev(msg->sg.which)
171 
172 #define sk_msg_iter_next(msg, which)			\
173 	sk_msg_iter_var_next(msg->sg.which)
174 
175 static inline void sk_msg_init(struct sk_msg *msg)
176 {
177 	BUILD_BUG_ON(ARRAY_SIZE(msg->sg.data) - 1 != NR_MSG_FRAG_IDS);
178 	memset(msg, 0, sizeof(*msg));
179 	sg_init_marker(msg->sg.data, NR_MSG_FRAG_IDS);
180 }
181 
182 static inline void sk_msg_xfer(struct sk_msg *dst, struct sk_msg *src,
183 			       int which, u32 size)
184 {
185 	dst->sg.data[which] = src->sg.data[which];
186 	dst->sg.data[which].length  = size;
187 	dst->sg.size		   += size;
188 	src->sg.size		   -= size;
189 	src->sg.data[which].length -= size;
190 	src->sg.data[which].offset += size;
191 }
192 
193 static inline void sk_msg_xfer_full(struct sk_msg *dst, struct sk_msg *src)
194 {
195 	memcpy(dst, src, sizeof(*src));
196 	sk_msg_init(src);
197 }
198 
199 static inline bool sk_msg_full(const struct sk_msg *msg)
200 {
201 	return sk_msg_iter_dist(msg->sg.start, msg->sg.end) == MAX_MSG_FRAGS;
202 }
203 
204 static inline u32 sk_msg_elem_used(const struct sk_msg *msg)
205 {
206 	return sk_msg_iter_dist(msg->sg.start, msg->sg.end);
207 }
208 
209 static inline struct scatterlist *sk_msg_elem(struct sk_msg *msg, int which)
210 {
211 	return &msg->sg.data[which];
212 }
213 
214 static inline struct scatterlist sk_msg_elem_cpy(struct sk_msg *msg, int which)
215 {
216 	return msg->sg.data[which];
217 }
218 
219 static inline struct page *sk_msg_page(struct sk_msg *msg, int which)
220 {
221 	return sg_page(sk_msg_elem(msg, which));
222 }
223 
224 static inline bool sk_msg_to_ingress(const struct sk_msg *msg)
225 {
226 	return msg->flags & BPF_F_INGRESS;
227 }
228 
229 static inline void sk_msg_compute_data_pointers(struct sk_msg *msg)
230 {
231 	struct scatterlist *sge = sk_msg_elem(msg, msg->sg.start);
232 
233 	if (test_bit(msg->sg.start, msg->sg.copy)) {
234 		msg->data = NULL;
235 		msg->data_end = NULL;
236 	} else {
237 		msg->data = sg_virt(sge);
238 		msg->data_end = msg->data + sge->length;
239 	}
240 }
241 
242 static inline void sk_msg_page_add(struct sk_msg *msg, struct page *page,
243 				   u32 len, u32 offset)
244 {
245 	struct scatterlist *sge;
246 
247 	get_page(page);
248 	sge = sk_msg_elem(msg, msg->sg.end);
249 	sg_set_page(sge, page, len, offset);
250 	sg_unmark_end(sge);
251 
252 	__set_bit(msg->sg.end, msg->sg.copy);
253 	msg->sg.size += len;
254 	sk_msg_iter_next(msg, end);
255 }
256 
257 static inline void sk_msg_sg_copy(struct sk_msg *msg, u32 i, bool copy_state)
258 {
259 	do {
260 		if (copy_state)
261 			__set_bit(i, msg->sg.copy);
262 		else
263 			__clear_bit(i, msg->sg.copy);
264 		sk_msg_iter_var_next(i);
265 		if (i == msg->sg.end)
266 			break;
267 	} while (1);
268 }
269 
270 static inline void sk_msg_sg_copy_set(struct sk_msg *msg, u32 start)
271 {
272 	sk_msg_sg_copy(msg, start, true);
273 }
274 
275 static inline void sk_msg_sg_copy_clear(struct sk_msg *msg, u32 start)
276 {
277 	sk_msg_sg_copy(msg, start, false);
278 }
279 
280 static inline struct sk_psock *sk_psock(const struct sock *sk)
281 {
282 	return __rcu_dereference_sk_user_data_with_flags(sk,
283 							 SK_USER_DATA_PSOCK);
284 }
285 
286 static inline void sk_psock_set_state(struct sk_psock *psock,
287 				      enum sk_psock_state_bits bit)
288 {
289 	set_bit(bit, &psock->state);
290 }
291 
292 static inline void sk_psock_clear_state(struct sk_psock *psock,
293 					enum sk_psock_state_bits bit)
294 {
295 	clear_bit(bit, &psock->state);
296 }
297 
298 static inline bool sk_psock_test_state(const struct sk_psock *psock,
299 				       enum sk_psock_state_bits bit)
300 {
301 	return test_bit(bit, &psock->state);
302 }
303 
304 static inline void sock_drop(struct sock *sk, struct sk_buff *skb)
305 {
306 	sk_drops_add(sk, skb);
307 	kfree_skb(skb);
308 }
309 
310 static inline void sk_psock_queue_msg(struct sk_psock *psock,
311 				      struct sk_msg *msg)
312 {
313 	spin_lock_bh(&psock->ingress_lock);
314 	if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
315 		list_add_tail(&msg->list, &psock->ingress_msg);
316 	else {
317 		sk_msg_free(psock->sk, msg);
318 		kfree(msg);
319 	}
320 	spin_unlock_bh(&psock->ingress_lock);
321 }
322 
323 static inline struct sk_msg *sk_psock_dequeue_msg(struct sk_psock *psock)
324 {
325 	struct sk_msg *msg;
326 
327 	spin_lock_bh(&psock->ingress_lock);
328 	msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
329 	if (msg)
330 		list_del(&msg->list);
331 	spin_unlock_bh(&psock->ingress_lock);
332 	return msg;
333 }
334 
335 static inline struct sk_msg *sk_psock_peek_msg(struct sk_psock *psock)
336 {
337 	struct sk_msg *msg;
338 
339 	spin_lock_bh(&psock->ingress_lock);
340 	msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
341 	spin_unlock_bh(&psock->ingress_lock);
342 	return msg;
343 }
344 
345 static inline struct sk_msg *sk_psock_next_msg(struct sk_psock *psock,
346 					       struct sk_msg *msg)
347 {
348 	struct sk_msg *ret;
349 
350 	spin_lock_bh(&psock->ingress_lock);
351 	if (list_is_last(&msg->list, &psock->ingress_msg))
352 		ret = NULL;
353 	else
354 		ret = list_next_entry(msg, list);
355 	spin_unlock_bh(&psock->ingress_lock);
356 	return ret;
357 }
358 
359 static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
360 {
361 	return psock ? list_empty(&psock->ingress_msg) : true;
362 }
363 
364 static inline void kfree_sk_msg(struct sk_msg *msg)
365 {
366 	if (msg->skb)
367 		consume_skb(msg->skb);
368 	kfree(msg);
369 }
370 
371 static inline void sk_psock_report_error(struct sk_psock *psock, int err)
372 {
373 	struct sock *sk = psock->sk;
374 
375 	sk->sk_err = err;
376 	sk_error_report(sk);
377 }
378 
379 struct sk_psock *sk_psock_init(struct sock *sk, int node);
380 void sk_psock_stop(struct sk_psock *psock);
381 
382 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
383 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
384 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
385 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
386 #else
387 static inline int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
388 {
389 	return -EOPNOTSUPP;
390 }
391 
392 static inline void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
393 {
394 }
395 
396 static inline void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
397 {
398 }
399 #endif
400 
401 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock);
402 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock);
403 
404 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
405 			 struct sk_msg *msg);
406 
407 static inline struct sk_psock_link *sk_psock_init_link(void)
408 {
409 	return kzalloc(sizeof(struct sk_psock_link),
410 		       GFP_ATOMIC | __GFP_NOWARN);
411 }
412 
413 static inline void sk_psock_free_link(struct sk_psock_link *link)
414 {
415 	kfree(link);
416 }
417 
418 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock);
419 
420 static inline void sk_psock_cork_free(struct sk_psock *psock)
421 {
422 	if (psock->cork) {
423 		sk_msg_free(psock->sk, psock->cork);
424 		kfree(psock->cork);
425 		psock->cork = NULL;
426 	}
427 }
428 
429 static inline void sk_psock_restore_proto(struct sock *sk,
430 					  struct sk_psock *psock)
431 {
432 	if (psock->psock_update_sk_prot)
433 		psock->psock_update_sk_prot(sk, psock, true);
434 }
435 
436 static inline struct sk_psock *sk_psock_get(struct sock *sk)
437 {
438 	struct sk_psock *psock;
439 
440 	rcu_read_lock();
441 	psock = sk_psock(sk);
442 	if (psock && !refcount_inc_not_zero(&psock->refcnt))
443 		psock = NULL;
444 	rcu_read_unlock();
445 	return psock;
446 }
447 
448 void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
449 
450 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
451 {
452 	if (refcount_dec_and_test(&psock->refcnt))
453 		sk_psock_drop(sk, psock);
454 }
455 
456 static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)
457 {
458 	if (psock->saved_data_ready)
459 		psock->saved_data_ready(sk);
460 	else
461 		sk->sk_data_ready(sk);
462 }
463 
464 static inline void psock_set_prog(struct bpf_prog **pprog,
465 				  struct bpf_prog *prog)
466 {
467 	prog = xchg(pprog, prog);
468 	if (prog)
469 		bpf_prog_put(prog);
470 }
471 
472 static inline int psock_replace_prog(struct bpf_prog **pprog,
473 				     struct bpf_prog *prog,
474 				     struct bpf_prog *old)
475 {
476 	if (cmpxchg(pprog, old, prog) != old)
477 		return -ENOENT;
478 
479 	if (old)
480 		bpf_prog_put(old);
481 
482 	return 0;
483 }
484 
485 static inline void psock_progs_drop(struct sk_psock_progs *progs)
486 {
487 	psock_set_prog(&progs->msg_parser, NULL);
488 	psock_set_prog(&progs->stream_parser, NULL);
489 	psock_set_prog(&progs->stream_verdict, NULL);
490 	psock_set_prog(&progs->skb_verdict, NULL);
491 }
492 
493 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb);
494 
495 static inline bool sk_psock_strp_enabled(struct sk_psock *psock)
496 {
497 	if (!psock)
498 		return false;
499 	return !!psock->saved_data_ready;
500 }
501 
502 static inline bool sk_is_udp(const struct sock *sk)
503 {
504 	return sk->sk_type == SOCK_DGRAM &&
505 	       sk->sk_protocol == IPPROTO_UDP;
506 }
507 
508 #if IS_ENABLED(CONFIG_NET_SOCK_MSG)
509 
510 #define BPF_F_STRPARSER	(1UL << 1)
511 
512 /* We only have two bits so far. */
513 #define BPF_F_PTR_MASK ~(BPF_F_INGRESS | BPF_F_STRPARSER)
514 
515 static inline bool skb_bpf_strparser(const struct sk_buff *skb)
516 {
517 	unsigned long sk_redir = skb->_sk_redir;
518 
519 	return sk_redir & BPF_F_STRPARSER;
520 }
521 
522 static inline void skb_bpf_set_strparser(struct sk_buff *skb)
523 {
524 	skb->_sk_redir |= BPF_F_STRPARSER;
525 }
526 
527 static inline bool skb_bpf_ingress(const struct sk_buff *skb)
528 {
529 	unsigned long sk_redir = skb->_sk_redir;
530 
531 	return sk_redir & BPF_F_INGRESS;
532 }
533 
534 static inline void skb_bpf_set_ingress(struct sk_buff *skb)
535 {
536 	skb->_sk_redir |= BPF_F_INGRESS;
537 }
538 
539 static inline void skb_bpf_set_redir(struct sk_buff *skb, struct sock *sk_redir,
540 				     bool ingress)
541 {
542 	skb->_sk_redir = (unsigned long)sk_redir;
543 	if (ingress)
544 		skb->_sk_redir |= BPF_F_INGRESS;
545 }
546 
547 static inline struct sock *skb_bpf_redirect_fetch(const struct sk_buff *skb)
548 {
549 	unsigned long sk_redir = skb->_sk_redir;
550 
551 	return (struct sock *)(sk_redir & BPF_F_PTR_MASK);
552 }
553 
554 static inline void skb_bpf_redirect_clear(struct sk_buff *skb)
555 {
556 	skb->_sk_redir = 0;
557 }
558 #endif /* CONFIG_NET_SOCK_MSG */
559 #endif /* _LINUX_SKMSG_H */
560