xref: /linux-6.15/include/linux/skmsg.h (revision bc128349) 
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 	unsigned long			copy;
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 static_assert(BITS_PER_LONG >= NR_MSG_FRAG_IDS);
42 
43 /* UAPI in filter.c depends on struct sk_msg_sg being first element. */
44 struct sk_msg {
45 	struct sk_msg_sg		sg;
46 	void				*data;
47 	void				*data_end;
48 	u32				apply_bytes;
49 	u32				cork_bytes;
50 	u32				flags;
51 	struct sk_buff			*skb;
52 	struct sock			*sk_redir;
53 	struct sock			*sk;
54 	struct list_head		list;
55 };
56 
57 struct sk_psock_progs {
58 	struct bpf_prog			*msg_parser;
59 	struct bpf_prog			*stream_parser;
60 	struct bpf_prog			*stream_verdict;
61 	struct bpf_prog			*skb_verdict;
62 };
63 
64 enum sk_psock_state_bits {
65 	SK_PSOCK_TX_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 	struct sk_buff			*skb;
76 	u32				len;
77 	u32				off;
78 };
79 
80 struct sk_psock {
81 	struct sock			*sk;
82 	struct sock			*sk_redir;
83 	u32				apply_bytes;
84 	u32				cork_bytes;
85 	u32				eval;
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_close)(struct sock *sk, long timeout);
100 	void (*saved_write_space)(struct sock *sk);
101 	void (*saved_data_ready)(struct sock *sk);
102 	int  (*psock_update_sk_prot)(struct sock *sk, struct sk_psock *psock,
103 				     bool restore);
104 	struct proto			*sk_proto;
105 	struct mutex			work_mutex;
106 	struct sk_psock_work_state	work_state;
107 	struct work_struct		work;
108 	struct rcu_work			rwork;
109 };
110 
111 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
112 		 int elem_first_coalesce);
113 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
114 		 u32 off, u32 len);
115 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len);
116 int sk_msg_free(struct sock *sk, struct sk_msg *msg);
117 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg);
118 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes);
119 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
120 				  u32 bytes);
121 
122 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes);
123 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes);
124 
125 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
126 			      struct sk_msg *msg, u32 bytes);
127 int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
128 			     struct sk_msg *msg, u32 bytes);
129 int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
130 		   int len, int flags);
131 bool sk_msg_is_readable(struct sock *sk);
132 
133 static inline void sk_msg_check_to_free(struct sk_msg *msg, u32 i, u32 bytes)
134 {
135 	WARN_ON(i == msg->sg.end && bytes);
136 }
137 
138 static inline void sk_msg_apply_bytes(struct sk_psock *psock, u32 bytes)
139 {
140 	if (psock->apply_bytes) {
141 		if (psock->apply_bytes < bytes)
142 			psock->apply_bytes = 0;
143 		else
144 			psock->apply_bytes -= bytes;
145 	}
146 }
147 
148 static inline u32 sk_msg_iter_dist(u32 start, u32 end)
149 {
150 	return end >= start ? end - start : end + (NR_MSG_FRAG_IDS - start);
151 }
152 
153 #define sk_msg_iter_var_prev(var)			\
154 	do {						\
155 		if (var == 0)				\
156 			var = NR_MSG_FRAG_IDS - 1;	\
157 		else					\
158 			var--;				\
159 	} while (0)
160 
161 #define sk_msg_iter_var_next(var)			\
162 	do {						\
163 		var++;					\
164 		if (var == NR_MSG_FRAG_IDS)		\
165 			var = 0;			\
166 	} while (0)
167 
168 #define sk_msg_iter_prev(msg, which)			\
169 	sk_msg_iter_var_prev(msg->sg.which)
170 
171 #define sk_msg_iter_next(msg, which)			\
172 	sk_msg_iter_var_next(msg->sg.which)
173 
174 static inline void sk_msg_clear_meta(struct sk_msg *msg)
175 {
176 	memset(&msg->sg, 0, offsetofend(struct sk_msg_sg, copy));
177 }
178 
179 static inline void sk_msg_init(struct sk_msg *msg)
180 {
181 	BUILD_BUG_ON(ARRAY_SIZE(msg->sg.data) - 1 != NR_MSG_FRAG_IDS);
182 	memset(msg, 0, sizeof(*msg));
183 	sg_init_marker(msg->sg.data, NR_MSG_FRAG_IDS);
184 }
185 
186 static inline void sk_msg_xfer(struct sk_msg *dst, struct sk_msg *src,
187 			       int which, u32 size)
188 {
189 	dst->sg.data[which] = src->sg.data[which];
190 	dst->sg.data[which].length  = size;
191 	dst->sg.size		   += size;
192 	src->sg.size		   -= size;
193 	src->sg.data[which].length -= size;
194 	src->sg.data[which].offset += size;
195 }
196 
197 static inline void sk_msg_xfer_full(struct sk_msg *dst, struct sk_msg *src)
198 {
199 	memcpy(dst, src, sizeof(*src));
200 	sk_msg_init(src);
201 }
202 
203 static inline bool sk_msg_full(const struct sk_msg *msg)
204 {
205 	return sk_msg_iter_dist(msg->sg.start, msg->sg.end) == MAX_MSG_FRAGS;
206 }
207 
208 static inline u32 sk_msg_elem_used(const struct sk_msg *msg)
209 {
210 	return sk_msg_iter_dist(msg->sg.start, msg->sg.end);
211 }
212 
213 static inline struct scatterlist *sk_msg_elem(struct sk_msg *msg, int which)
214 {
215 	return &msg->sg.data[which];
216 }
217 
218 static inline struct scatterlist sk_msg_elem_cpy(struct sk_msg *msg, int which)
219 {
220 	return msg->sg.data[which];
221 }
222 
223 static inline struct page *sk_msg_page(struct sk_msg *msg, int which)
224 {
225 	return sg_page(sk_msg_elem(msg, which));
226 }
227 
228 static inline bool sk_msg_to_ingress(const struct sk_msg *msg)
229 {
230 	return msg->flags & BPF_F_INGRESS;
231 }
232 
233 static inline void sk_msg_compute_data_pointers(struct sk_msg *msg)
234 {
235 	struct scatterlist *sge = sk_msg_elem(msg, msg->sg.start);
236 
237 	if (test_bit(msg->sg.start, &msg->sg.copy)) {
238 		msg->data = NULL;
239 		msg->data_end = NULL;
240 	} else {
241 		msg->data = sg_virt(sge);
242 		msg->data_end = msg->data + sge->length;
243 	}
244 }
245 
246 static inline void sk_msg_page_add(struct sk_msg *msg, struct page *page,
247 				   u32 len, u32 offset)
248 {
249 	struct scatterlist *sge;
250 
251 	get_page(page);
252 	sge = sk_msg_elem(msg, msg->sg.end);
253 	sg_set_page(sge, page, len, offset);
254 	sg_unmark_end(sge);
255 
256 	__set_bit(msg->sg.end, &msg->sg.copy);
257 	msg->sg.size += len;
258 	sk_msg_iter_next(msg, end);
259 }
260 
261 static inline void sk_msg_sg_copy(struct sk_msg *msg, u32 i, bool copy_state)
262 {
263 	do {
264 		if (copy_state)
265 			__set_bit(i, &msg->sg.copy);
266 		else
267 			__clear_bit(i, &msg->sg.copy);
268 		sk_msg_iter_var_next(i);
269 		if (i == msg->sg.end)
270 			break;
271 	} while (1);
272 }
273 
274 static inline void sk_msg_sg_copy_set(struct sk_msg *msg, u32 start)
275 {
276 	sk_msg_sg_copy(msg, start, true);
277 }
278 
279 static inline void sk_msg_sg_copy_clear(struct sk_msg *msg, u32 start)
280 {
281 	sk_msg_sg_copy(msg, start, false);
282 }
283 
284 static inline struct sk_psock *sk_psock(const struct sock *sk)
285 {
286 	return rcu_dereference_sk_user_data(sk);
287 }
288 
289 static inline void sk_psock_set_state(struct sk_psock *psock,
290 				      enum sk_psock_state_bits bit)
291 {
292 	set_bit(bit, &psock->state);
293 }
294 
295 static inline void sk_psock_clear_state(struct sk_psock *psock,
296 					enum sk_psock_state_bits bit)
297 {
298 	clear_bit(bit, &psock->state);
299 }
300 
301 static inline bool sk_psock_test_state(const struct sk_psock *psock,
302 				       enum sk_psock_state_bits bit)
303 {
304 	return test_bit(bit, &psock->state);
305 }
306 
307 static inline void sock_drop(struct sock *sk, struct sk_buff *skb)
308 {
309 	sk_drops_add(sk, skb);
310 	kfree_skb(skb);
311 }
312 
313 static inline void drop_sk_msg(struct sk_psock *psock, struct sk_msg *msg)
314 {
315 	if (msg->skb)
316 		sock_drop(psock->sk, msg->skb);
317 	kfree(msg);
318 }
319 
320 static inline void sk_psock_queue_msg(struct sk_psock *psock,
321 				      struct sk_msg *msg)
322 {
323 	spin_lock_bh(&psock->ingress_lock);
324 	if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
325 		list_add_tail(&msg->list, &psock->ingress_msg);
326 	else
327 		drop_sk_msg(psock, msg);
328 	spin_unlock_bh(&psock->ingress_lock);
329 }
330 
331 static inline struct sk_msg *sk_psock_dequeue_msg(struct sk_psock *psock)
332 {
333 	struct sk_msg *msg;
334 
335 	spin_lock_bh(&psock->ingress_lock);
336 	msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
337 	if (msg)
338 		list_del(&msg->list);
339 	spin_unlock_bh(&psock->ingress_lock);
340 	return msg;
341 }
342 
343 static inline struct sk_msg *sk_psock_peek_msg(struct sk_psock *psock)
344 {
345 	struct sk_msg *msg;
346 
347 	spin_lock_bh(&psock->ingress_lock);
348 	msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
349 	spin_unlock_bh(&psock->ingress_lock);
350 	return msg;
351 }
352 
353 static inline struct sk_msg *sk_psock_next_msg(struct sk_psock *psock,
354 					       struct sk_msg *msg)
355 {
356 	struct sk_msg *ret;
357 
358 	spin_lock_bh(&psock->ingress_lock);
359 	if (list_is_last(&msg->list, &psock->ingress_msg))
360 		ret = NULL;
361 	else
362 		ret = list_next_entry(msg, list);
363 	spin_unlock_bh(&psock->ingress_lock);
364 	return ret;
365 }
366 
367 static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
368 {
369 	return psock ? list_empty(&psock->ingress_msg) : true;
370 }
371 
372 static inline void kfree_sk_msg(struct sk_msg *msg)
373 {
374 	if (msg->skb)
375 		consume_skb(msg->skb);
376 	kfree(msg);
377 }
378 
379 static inline void sk_psock_report_error(struct sk_psock *psock, int err)
380 {
381 	struct sock *sk = psock->sk;
382 
383 	sk->sk_err = err;
384 	sk_error_report(sk);
385 }
386 
387 struct sk_psock *sk_psock_init(struct sock *sk, int node);
388 void sk_psock_stop(struct sk_psock *psock, bool wait);
389 
390 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
391 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
392 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
393 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
394 #else
395 static inline int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
396 {
397 	return -EOPNOTSUPP;
398 }
399 
400 static inline void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
401 {
402 }
403 
404 static inline void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
405 {
406 }
407 #endif
408 
409 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock);
410 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock);
411 
412 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
413 			 struct sk_msg *msg);
414 
415 static inline struct sk_psock_link *sk_psock_init_link(void)
416 {
417 	return kzalloc(sizeof(struct sk_psock_link),
418 		       GFP_ATOMIC | __GFP_NOWARN);
419 }
420 
421 static inline void sk_psock_free_link(struct sk_psock_link *link)
422 {
423 	kfree(link);
424 }
425 
426 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock);
427 
428 static inline void sk_psock_cork_free(struct sk_psock *psock)
429 {
430 	if (psock->cork) {
431 		sk_msg_free(psock->sk, psock->cork);
432 		kfree(psock->cork);
433 		psock->cork = NULL;
434 	}
435 }
436 
437 static inline void sk_psock_restore_proto(struct sock *sk,
438 					  struct sk_psock *psock)
439 {
440 	if (psock->psock_update_sk_prot)
441 		psock->psock_update_sk_prot(sk, psock, true);
442 }
443 
444 static inline struct sk_psock *sk_psock_get(struct sock *sk)
445 {
446 	struct sk_psock *psock;
447 
448 	rcu_read_lock();
449 	psock = sk_psock(sk);
450 	if (psock && !refcount_inc_not_zero(&psock->refcnt))
451 		psock = NULL;
452 	rcu_read_unlock();
453 	return psock;
454 }
455 
456 void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
457 
458 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
459 {
460 	if (refcount_dec_and_test(&psock->refcnt))
461 		sk_psock_drop(sk, psock);
462 }
463 
464 static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)
465 {
466 	if (psock->saved_data_ready)
467 		psock->saved_data_ready(sk);
468 	else
469 		sk->sk_data_ready(sk);
470 }
471 
472 static inline void psock_set_prog(struct bpf_prog **pprog,
473 				  struct bpf_prog *prog)
474 {
475 	prog = xchg(pprog, prog);
476 	if (prog)
477 		bpf_prog_put(prog);
478 }
479 
480 static inline int psock_replace_prog(struct bpf_prog **pprog,
481 				     struct bpf_prog *prog,
482 				     struct bpf_prog *old)
483 {
484 	if (cmpxchg(pprog, old, prog) != old)
485 		return -ENOENT;
486 
487 	if (old)
488 		bpf_prog_put(old);
489 
490 	return 0;
491 }
492 
493 static inline void psock_progs_drop(struct sk_psock_progs *progs)
494 {
495 	psock_set_prog(&progs->msg_parser, NULL);
496 	psock_set_prog(&progs->stream_parser, NULL);
497 	psock_set_prog(&progs->stream_verdict, NULL);
498 	psock_set_prog(&progs->skb_verdict, NULL);
499 }
500 
501 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb);
502 
503 static inline bool sk_psock_strp_enabled(struct sk_psock *psock)
504 {
505 	if (!psock)
506 		return false;
507 	return !!psock->saved_data_ready;
508 }
509 
510 static inline bool sk_is_tcp(const struct sock *sk)
511 {
512 	return sk->sk_type == SOCK_STREAM &&
513 	       sk->sk_protocol == IPPROTO_TCP;
514 }
515 
516 static inline bool sk_is_udp(const struct sock *sk)
517 {
518 	return sk->sk_type == SOCK_DGRAM &&
519 	       sk->sk_protocol == IPPROTO_UDP;
520 }
521 
522 #if IS_ENABLED(CONFIG_NET_SOCK_MSG)
523 
524 #define BPF_F_STRPARSER	(1UL << 1)
525 
526 /* We only have two bits so far. */
527 #define BPF_F_PTR_MASK ~(BPF_F_INGRESS | BPF_F_STRPARSER)
528 
529 static inline bool skb_bpf_strparser(const struct sk_buff *skb)
530 {
531 	unsigned long sk_redir = skb->_sk_redir;
532 
533 	return sk_redir & BPF_F_STRPARSER;
534 }
535 
536 static inline void skb_bpf_set_strparser(struct sk_buff *skb)
537 {
538 	skb->_sk_redir |= BPF_F_STRPARSER;
539 }
540 
541 static inline bool skb_bpf_ingress(const struct sk_buff *skb)
542 {
543 	unsigned long sk_redir = skb->_sk_redir;
544 
545 	return sk_redir & BPF_F_INGRESS;
546 }
547 
548 static inline void skb_bpf_set_ingress(struct sk_buff *skb)
549 {
550 	skb->_sk_redir |= BPF_F_INGRESS;
551 }
552 
553 static inline void skb_bpf_set_redir(struct sk_buff *skb, struct sock *sk_redir,
554 				     bool ingress)
555 {
556 	skb->_sk_redir = (unsigned long)sk_redir;
557 	if (ingress)
558 		skb->_sk_redir |= BPF_F_INGRESS;
559 }
560 
561 static inline struct sock *skb_bpf_redirect_fetch(const struct sk_buff *skb)
562 {
563 	unsigned long sk_redir = skb->_sk_redir;
564 
565 	return (struct sock *)(sk_redir & BPF_F_PTR_MASK);
566 }
567 
568 static inline void skb_bpf_redirect_clear(struct sk_buff *skb)
569 {
570 	skb->_sk_redir = 0;
571 }
572 #endif /* CONFIG_NET_SOCK_MSG */
573 #endif /* _LINUX_SKMSG_H */
574