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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 *skb_parser;
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_parser {
74 struct strparser strp;
75 bool enabled;
76 void (*saved_data_ready)(struct sock *sk);
77 };
78
79 struct sk_psock_work_state {
80 struct sk_buff *skb;
81 u32 len;
82 u32 off;
83 };
84
85 struct sk_psock {
86 struct sock *sk;
87 struct sock *sk_redir;
88 u32 apply_bytes;
89 u32 cork_bytes;
90 u32 eval;
91 struct sk_msg *cork;
92 struct sk_psock_progs progs;
93 struct sk_psock_parser parser;
94 struct sk_buff_head ingress_skb;
95 struct list_head ingress_msg;
96 unsigned long state;
97 struct list_head link;
98 spinlock_t link_lock;
99 refcount_t refcnt;
100 void (*saved_unhash)(struct sock *sk);
101 void (*saved_close)(struct sock *sk, long timeout);
102 void (*saved_write_space)(struct sock *sk);
103 struct proto *sk_proto;
104 struct sk_psock_work_state work_state;
105 struct work_struct work;
106 union {
107 struct rcu_head rcu;
108 struct work_struct gc;
109 };
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
131 static inline void sk_msg_check_to_free(struct sk_msg *msg, u32 i, u32 bytes)
132 {
133 WARN_ON(i == msg->sg.end && bytes);
134 }
135
136 static inline void sk_msg_apply_bytes(struct sk_psock *psock, u32 bytes)
137 {
138 if (psock->apply_bytes) {
139 if (psock->apply_bytes < bytes)
140 psock->apply_bytes = 0;
141 else
142 psock->apply_bytes -= bytes;
143 }
144 }
145
146 static inline u32 sk_msg_iter_dist(u32 start, u32 end)
147 {
148 return end >= start ? end - start : end + (NR_MSG_FRAG_IDS - start);
149 }
150
151 #define sk_msg_iter_var_prev(var) \
152 do { \
153 if (var == 0) \
154 var = NR_MSG_FRAG_IDS - 1; \
155 else \
156 var--; \
157 } while (0)
158
159 #define sk_msg_iter_var_next(var) \
160 do { \
161 var++; \
162 if (var == NR_MSG_FRAG_IDS) \
163 var = 0; \
164 } while (0)
165
166 #define sk_msg_iter_prev(msg, which) \
167 sk_msg_iter_var_prev(msg->sg.which)
168
169 #define sk_msg_iter_next(msg, which) \
170 sk_msg_iter_var_next(msg->sg.which)
171
172 static inline void sk_msg_clear_meta(struct sk_msg *msg)
173 {
174 memset(&msg->sg, 0, offsetofend(struct sk_msg_sg, copy));
175 }
176
177 static inline void sk_msg_init(struct sk_msg *msg)
178 {
179 BUILD_BUG_ON(ARRAY_SIZE(msg->sg.data) - 1 != NR_MSG_FRAG_IDS);
180 memset(msg, 0, sizeof(*msg));
181 sg_init_marker(msg->sg.data, NR_MSG_FRAG_IDS);
182 }
183
184 static inline void sk_msg_xfer(struct sk_msg *dst, struct sk_msg *src,
185 int which, u32 size)
186 {
187 dst->sg.data[which] = src->sg.data[which];
188 dst->sg.data[which].length = size;
189 dst->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(sk);
284 }
285
286 static inline void sk_psock_queue_msg(struct sk_psock *psock,
287 struct sk_msg *msg)
288 {
289 list_add_tail(&msg->list, &psock->ingress_msg);
290 }
291
292 static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
293 {
294 return psock ? list_empty(&psock->ingress_msg) : true;
295 }
296
297 static inline void sk_psock_report_error(struct sk_psock *psock, int err)
298 {
299 struct sock *sk = psock->sk;
300
301 sk->sk_err = err;
302 sk->sk_error_report(sk);
303 }
304
305 struct sk_psock *sk_psock_init(struct sock *sk, int node);
306
307 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
308 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
309 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
310
311 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
312 struct sk_msg *msg);
313
314 static inline struct sk_psock_link *sk_psock_init_link(void)
315 {
316 return kzalloc(sizeof(struct sk_psock_link),
317 GFP_ATOMIC | __GFP_NOWARN);
318 }
319
320 static inline void sk_psock_free_link(struct sk_psock_link *link)
321 {
322 kfree(link);
323 }
324
325 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock);
326
327 void __sk_psock_purge_ingress_msg(struct sk_psock *psock);
328
329 static inline void sk_psock_cork_free(struct sk_psock *psock)
330 {
331 if (psock->cork) {
332 sk_msg_free(psock->sk, psock->cork);
333 kfree(psock->cork);
334 psock->cork = NULL;
335 }
336 }
337
338 static inline void sk_psock_update_proto(struct sock *sk,
339 struct sk_psock *psock,
340 struct proto *ops)
341 {
342 /* Initialize saved callbacks and original proto only once, since this
343 * function may be called multiple times for a psock, e.g. when
344 * psock->progs.msg_parser is updated.
345 *
346 * Since we've not installed the new proto, psock is not yet in use and
347 * we can initialize it without synchronization.
348 */
349 if (!psock->sk_proto) {
350 struct proto *orig = READ_ONCE(sk->sk_prot);
351
352 psock->saved_unhash = orig->unhash;
353 psock->saved_close = orig->close;
354 psock->saved_write_space = sk->sk_write_space;
355
356 psock->sk_proto = orig;
357 }
358
359 /* Pairs with lockless read in sk_clone_lock() */
360 WRITE_ONCE(sk->sk_prot, ops);
361 }
362
363 static inline void sk_psock_restore_proto(struct sock *sk,
364 struct sk_psock *psock)
365 {
366 sk->sk_prot->unhash = psock->saved_unhash;
367 if (inet_csk_has_ulp(sk)) {
368 tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
369 } else {
370 sk->sk_write_space = psock->saved_write_space;
371 /* Pairs with lockless read in sk_clone_lock() */
372 WRITE_ONCE(sk->sk_prot, psock->sk_proto);
373 }
374 }
375
376 static inline void sk_psock_set_state(struct sk_psock *psock,
377 enum sk_psock_state_bits bit)
378 {
379 set_bit(bit, &psock->state);
380 }
381
382 static inline void sk_psock_clear_state(struct sk_psock *psock,
383 enum sk_psock_state_bits bit)
384 {
385 clear_bit(bit, &psock->state);
386 }
387
388 static inline bool sk_psock_test_state(const struct sk_psock *psock,
389 enum sk_psock_state_bits bit)
390 {
391 return test_bit(bit, &psock->state);
392 }
393
394 static inline struct sk_psock *sk_psock_get(struct sock *sk)
395 {
396 struct sk_psock *psock;
397
398 rcu_read_lock();
399 psock = sk_psock(sk);
400 if (psock && !refcount_inc_not_zero(&psock->refcnt))
401 psock = NULL;
402 rcu_read_unlock();
403 return psock;
404 }
405
406 void sk_psock_stop(struct sock *sk, struct sk_psock *psock);
407 void sk_psock_destroy(struct rcu_head *rcu);
408 void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
409
410 static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
411 {
412 if (refcount_dec_and_test(&psock->refcnt))
413 sk_psock_drop(sk, psock);
414 }
415
416 static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)
417 {
418 if (psock->parser.enabled)
419 psock->parser.saved_data_ready(sk);
420 else
421 sk->sk_data_ready(sk);
422 }
423
424 static inline void psock_set_prog(struct bpf_prog **pprog,
425 struct bpf_prog *prog)
426 {
427 prog = xchg(pprog, prog);
428 if (prog)
429 bpf_prog_put(prog);
430 }
431
432 static inline void psock_progs_drop(struct sk_psock_progs *progs)
433 {
434 psock_set_prog(&progs->msg_parser, NULL);
435 psock_set_prog(&progs->skb_parser, NULL);
436 psock_set_prog(&progs->skb_verdict, NULL);
437 }
438
439 #endif /* _LINUX_SKMSG_H */