xref: /linux/io_uring/net.c (revision 8e3ed5440b0c305dcd1d5fa7419bd8066d22ef42)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/errno.h>
4 #include <linux/file.h>
5 #include <linux/slab.h>
6 #include <linux/net.h>
7 #include <linux/compat.h>
8 #include <net/compat.h>
9 #include <linux/io_uring.h>
10 
11 #include <uapi/linux/io_uring.h>
12 
13 #include "io_uring.h"
14 #include "kbuf.h"
15 #include "alloc_cache.h"
16 #include "net.h"
17 #include "notif.h"
18 #include "rsrc.h"
19 
20 #if defined(CONFIG_NET)
21 struct io_shutdown {
22 	struct file			*file;
23 	int				how;
24 };
25 
26 struct io_accept {
27 	struct file			*file;
28 	struct sockaddr __user		*addr;
29 	int __user			*addr_len;
30 	int				flags;
31 	u32				file_slot;
32 	unsigned long			nofile;
33 };
34 
35 struct io_socket {
36 	struct file			*file;
37 	int				domain;
38 	int				type;
39 	int				protocol;
40 	int				flags;
41 	u32				file_slot;
42 	unsigned long			nofile;
43 };
44 
45 struct io_connect {
46 	struct file			*file;
47 	struct sockaddr __user		*addr;
48 	int				addr_len;
49 	bool				in_progress;
50 	bool				seen_econnaborted;
51 };
52 
53 struct io_sr_msg {
54 	struct file			*file;
55 	union {
56 		struct compat_msghdr __user	*umsg_compat;
57 		struct user_msghdr __user	*umsg;
58 		void __user			*buf;
59 	};
60 	unsigned			len;
61 	unsigned			done_io;
62 	unsigned			msg_flags;
63 	unsigned			nr_multishot_loops;
64 	u16				flags;
65 	/* initialised and used only by !msg send variants */
66 	u16				addr_len;
67 	u16				buf_group;
68 	void __user			*addr;
69 	void __user			*msg_control;
70 	/* used only for send zerocopy */
71 	struct io_kiocb 		*notif;
72 };
73 
74 /*
75  * Number of times we'll try and do receives if there's more data. If we
76  * exceed this limit, then add us to the back of the queue and retry from
77  * there. This helps fairness between flooding clients.
78  */
79 #define MULTISHOT_MAX_RETRY	32
80 
81 static inline bool io_check_multishot(struct io_kiocb *req,
82 				      unsigned int issue_flags)
83 {
84 	/*
85 	 * When ->locked_cq is set we only allow to post CQEs from the original
86 	 * task context. Usual request completions will be handled in other
87 	 * generic paths but multipoll may decide to post extra cqes.
88 	 */
89 	return !(issue_flags & IO_URING_F_IOWQ) ||
90 		!(issue_flags & IO_URING_F_MULTISHOT) ||
91 		!req->ctx->task_complete;
92 }
93 
94 int io_shutdown_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
95 {
96 	struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
97 
98 	if (unlikely(sqe->off || sqe->addr || sqe->rw_flags ||
99 		     sqe->buf_index || sqe->splice_fd_in))
100 		return -EINVAL;
101 
102 	shutdown->how = READ_ONCE(sqe->len);
103 	req->flags |= REQ_F_FORCE_ASYNC;
104 	return 0;
105 }
106 
107 int io_shutdown(struct io_kiocb *req, unsigned int issue_flags)
108 {
109 	struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
110 	struct socket *sock;
111 	int ret;
112 
113 	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
114 
115 	sock = sock_from_file(req->file);
116 	if (unlikely(!sock))
117 		return -ENOTSOCK;
118 
119 	ret = __sys_shutdown_sock(sock, shutdown->how);
120 	io_req_set_res(req, ret, 0);
121 	return IOU_OK;
122 }
123 
124 static bool io_net_retry(struct socket *sock, int flags)
125 {
126 	if (!(flags & MSG_WAITALL))
127 		return false;
128 	return sock->type == SOCK_STREAM || sock->type == SOCK_SEQPACKET;
129 }
130 
131 static void io_netmsg_recycle(struct io_kiocb *req, unsigned int issue_flags)
132 {
133 	struct io_async_msghdr *hdr = req->async_data;
134 
135 	if (!req_has_async_data(req) || issue_flags & IO_URING_F_UNLOCKED)
136 		return;
137 
138 	/* Let normal cleanup path reap it if we fail adding to the cache */
139 	if (io_alloc_cache_put(&req->ctx->netmsg_cache, &hdr->cache)) {
140 		req->async_data = NULL;
141 		req->flags &= ~REQ_F_ASYNC_DATA;
142 	}
143 }
144 
145 static struct io_async_msghdr *io_msg_alloc_async(struct io_kiocb *req,
146 						  unsigned int issue_flags)
147 {
148 	struct io_ring_ctx *ctx = req->ctx;
149 	struct io_cache_entry *entry;
150 	struct io_async_msghdr *hdr;
151 
152 	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
153 		entry = io_alloc_cache_get(&ctx->netmsg_cache);
154 		if (entry) {
155 			hdr = container_of(entry, struct io_async_msghdr, cache);
156 			hdr->free_iov = NULL;
157 			req->flags |= REQ_F_ASYNC_DATA;
158 			req->async_data = hdr;
159 			return hdr;
160 		}
161 	}
162 
163 	if (!io_alloc_async_data(req)) {
164 		hdr = req->async_data;
165 		hdr->free_iov = NULL;
166 		return hdr;
167 	}
168 	return NULL;
169 }
170 
171 static inline struct io_async_msghdr *io_msg_alloc_async_prep(struct io_kiocb *req)
172 {
173 	/* ->prep_async is always called from the submission context */
174 	return io_msg_alloc_async(req, 0);
175 }
176 
177 static int io_setup_async_msg(struct io_kiocb *req,
178 			      struct io_async_msghdr *kmsg,
179 			      unsigned int issue_flags)
180 {
181 	struct io_async_msghdr *async_msg;
182 
183 	if (req_has_async_data(req))
184 		return -EAGAIN;
185 	async_msg = io_msg_alloc_async(req, issue_flags);
186 	if (!async_msg) {
187 		kfree(kmsg->free_iov);
188 		return -ENOMEM;
189 	}
190 	req->flags |= REQ_F_NEED_CLEANUP;
191 	memcpy(async_msg, kmsg, sizeof(*kmsg));
192 	if (async_msg->msg.msg_name)
193 		async_msg->msg.msg_name = &async_msg->addr;
194 
195 	if ((req->flags & REQ_F_BUFFER_SELECT) && !async_msg->msg.msg_iter.nr_segs)
196 		return -EAGAIN;
197 
198 	/* if were using fast_iov, set it to the new one */
199 	if (iter_is_iovec(&kmsg->msg.msg_iter) && !kmsg->free_iov) {
200 		size_t fast_idx = iter_iov(&kmsg->msg.msg_iter) - kmsg->fast_iov;
201 		async_msg->msg.msg_iter.__iov = &async_msg->fast_iov[fast_idx];
202 	}
203 
204 	return -EAGAIN;
205 }
206 
207 static int io_sendmsg_copy_hdr(struct io_kiocb *req,
208 			       struct io_async_msghdr *iomsg)
209 {
210 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
211 	int ret;
212 
213 	iomsg->msg.msg_name = &iomsg->addr;
214 	iomsg->free_iov = iomsg->fast_iov;
215 	ret = sendmsg_copy_msghdr(&iomsg->msg, sr->umsg, sr->msg_flags,
216 					&iomsg->free_iov);
217 	/* save msg_control as sys_sendmsg() overwrites it */
218 	sr->msg_control = iomsg->msg.msg_control_user;
219 	return ret;
220 }
221 
222 int io_send_prep_async(struct io_kiocb *req)
223 {
224 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
225 	struct io_async_msghdr *io;
226 	int ret;
227 
228 	if (!zc->addr || req_has_async_data(req))
229 		return 0;
230 	io = io_msg_alloc_async_prep(req);
231 	if (!io)
232 		return -ENOMEM;
233 	ret = move_addr_to_kernel(zc->addr, zc->addr_len, &io->addr);
234 	return ret;
235 }
236 
237 static int io_setup_async_addr(struct io_kiocb *req,
238 			      struct sockaddr_storage *addr_storage,
239 			      unsigned int issue_flags)
240 {
241 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
242 	struct io_async_msghdr *io;
243 
244 	if (!sr->addr || req_has_async_data(req))
245 		return -EAGAIN;
246 	io = io_msg_alloc_async(req, issue_flags);
247 	if (!io)
248 		return -ENOMEM;
249 	memcpy(&io->addr, addr_storage, sizeof(io->addr));
250 	return -EAGAIN;
251 }
252 
253 int io_sendmsg_prep_async(struct io_kiocb *req)
254 {
255 	int ret;
256 
257 	if (!io_msg_alloc_async_prep(req))
258 		return -ENOMEM;
259 	ret = io_sendmsg_copy_hdr(req, req->async_data);
260 	if (!ret)
261 		req->flags |= REQ_F_NEED_CLEANUP;
262 	return ret;
263 }
264 
265 void io_sendmsg_recvmsg_cleanup(struct io_kiocb *req)
266 {
267 	struct io_async_msghdr *io = req->async_data;
268 
269 	kfree(io->free_iov);
270 }
271 
272 int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
273 {
274 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
275 
276 	if (req->opcode == IORING_OP_SEND) {
277 		if (READ_ONCE(sqe->__pad3[0]))
278 			return -EINVAL;
279 		sr->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
280 		sr->addr_len = READ_ONCE(sqe->addr_len);
281 	} else if (sqe->addr2 || sqe->file_index) {
282 		return -EINVAL;
283 	}
284 
285 	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
286 	sr->len = READ_ONCE(sqe->len);
287 	sr->flags = READ_ONCE(sqe->ioprio);
288 	if (sr->flags & ~IORING_RECVSEND_POLL_FIRST)
289 		return -EINVAL;
290 	sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
291 	if (sr->msg_flags & MSG_DONTWAIT)
292 		req->flags |= REQ_F_NOWAIT;
293 
294 #ifdef CONFIG_COMPAT
295 	if (req->ctx->compat)
296 		sr->msg_flags |= MSG_CMSG_COMPAT;
297 #endif
298 	sr->done_io = 0;
299 	return 0;
300 }
301 
302 int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
303 {
304 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
305 	struct io_async_msghdr iomsg, *kmsg;
306 	struct socket *sock;
307 	unsigned flags;
308 	int min_ret = 0;
309 	int ret;
310 
311 	sock = sock_from_file(req->file);
312 	if (unlikely(!sock))
313 		return -ENOTSOCK;
314 
315 	if (req_has_async_data(req)) {
316 		kmsg = req->async_data;
317 		kmsg->msg.msg_control_user = sr->msg_control;
318 	} else {
319 		ret = io_sendmsg_copy_hdr(req, &iomsg);
320 		if (ret)
321 			return ret;
322 		kmsg = &iomsg;
323 	}
324 
325 	if (!(req->flags & REQ_F_POLLED) &&
326 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
327 		return io_setup_async_msg(req, kmsg, issue_flags);
328 
329 	flags = sr->msg_flags;
330 	if (issue_flags & IO_URING_F_NONBLOCK)
331 		flags |= MSG_DONTWAIT;
332 	if (flags & MSG_WAITALL)
333 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
334 
335 	ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
336 
337 	if (ret < min_ret) {
338 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
339 			return io_setup_async_msg(req, kmsg, issue_flags);
340 		if (ret > 0 && io_net_retry(sock, flags)) {
341 			kmsg->msg.msg_controllen = 0;
342 			kmsg->msg.msg_control = NULL;
343 			sr->done_io += ret;
344 			req->flags |= REQ_F_PARTIAL_IO;
345 			return io_setup_async_msg(req, kmsg, issue_flags);
346 		}
347 		if (ret == -ERESTARTSYS)
348 			ret = -EINTR;
349 		req_set_fail(req);
350 	}
351 	/* fast path, check for non-NULL to avoid function call */
352 	if (kmsg->free_iov)
353 		kfree(kmsg->free_iov);
354 	req->flags &= ~REQ_F_NEED_CLEANUP;
355 	io_netmsg_recycle(req, issue_flags);
356 	if (ret >= 0)
357 		ret += sr->done_io;
358 	else if (sr->done_io)
359 		ret = sr->done_io;
360 	io_req_set_res(req, ret, 0);
361 	return IOU_OK;
362 }
363 
364 int io_send(struct io_kiocb *req, unsigned int issue_flags)
365 {
366 	struct sockaddr_storage __address;
367 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
368 	struct msghdr msg;
369 	struct socket *sock;
370 	unsigned flags;
371 	int min_ret = 0;
372 	int ret;
373 
374 	msg.msg_name = NULL;
375 	msg.msg_control = NULL;
376 	msg.msg_controllen = 0;
377 	msg.msg_namelen = 0;
378 	msg.msg_ubuf = NULL;
379 
380 	if (sr->addr) {
381 		if (req_has_async_data(req)) {
382 			struct io_async_msghdr *io = req->async_data;
383 
384 			msg.msg_name = &io->addr;
385 		} else {
386 			ret = move_addr_to_kernel(sr->addr, sr->addr_len, &__address);
387 			if (unlikely(ret < 0))
388 				return ret;
389 			msg.msg_name = (struct sockaddr *)&__address;
390 		}
391 		msg.msg_namelen = sr->addr_len;
392 	}
393 
394 	if (!(req->flags & REQ_F_POLLED) &&
395 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
396 		return io_setup_async_addr(req, &__address, issue_flags);
397 
398 	sock = sock_from_file(req->file);
399 	if (unlikely(!sock))
400 		return -ENOTSOCK;
401 
402 	ret = import_ubuf(ITER_SOURCE, sr->buf, sr->len, &msg.msg_iter);
403 	if (unlikely(ret))
404 		return ret;
405 
406 	flags = sr->msg_flags;
407 	if (issue_flags & IO_URING_F_NONBLOCK)
408 		flags |= MSG_DONTWAIT;
409 	if (flags & MSG_WAITALL)
410 		min_ret = iov_iter_count(&msg.msg_iter);
411 
412 	flags &= ~MSG_INTERNAL_SENDMSG_FLAGS;
413 	msg.msg_flags = flags;
414 	ret = sock_sendmsg(sock, &msg);
415 	if (ret < min_ret) {
416 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
417 			return io_setup_async_addr(req, &__address, issue_flags);
418 
419 		if (ret > 0 && io_net_retry(sock, flags)) {
420 			sr->len -= ret;
421 			sr->buf += ret;
422 			sr->done_io += ret;
423 			req->flags |= REQ_F_PARTIAL_IO;
424 			return io_setup_async_addr(req, &__address, issue_flags);
425 		}
426 		if (ret == -ERESTARTSYS)
427 			ret = -EINTR;
428 		req_set_fail(req);
429 	}
430 	if (ret >= 0)
431 		ret += sr->done_io;
432 	else if (sr->done_io)
433 		ret = sr->done_io;
434 	io_req_set_res(req, ret, 0);
435 	return IOU_OK;
436 }
437 
438 static bool io_recvmsg_multishot_overflow(struct io_async_msghdr *iomsg)
439 {
440 	int hdr;
441 
442 	if (iomsg->namelen < 0)
443 		return true;
444 	if (check_add_overflow((int)sizeof(struct io_uring_recvmsg_out),
445 			       iomsg->namelen, &hdr))
446 		return true;
447 	if (check_add_overflow(hdr, (int)iomsg->controllen, &hdr))
448 		return true;
449 
450 	return false;
451 }
452 
453 static int __io_recvmsg_copy_hdr(struct io_kiocb *req,
454 				 struct io_async_msghdr *iomsg)
455 {
456 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
457 	struct user_msghdr msg;
458 	int ret;
459 
460 	if (copy_from_user(&msg, sr->umsg, sizeof(*sr->umsg)))
461 		return -EFAULT;
462 
463 	ret = __copy_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
464 	if (ret)
465 		return ret;
466 
467 	if (req->flags & REQ_F_BUFFER_SELECT) {
468 		if (msg.msg_iovlen == 0) {
469 			sr->len = iomsg->fast_iov[0].iov_len = 0;
470 			iomsg->fast_iov[0].iov_base = NULL;
471 			iomsg->free_iov = NULL;
472 		} else if (msg.msg_iovlen > 1) {
473 			return -EINVAL;
474 		} else {
475 			if (copy_from_user(iomsg->fast_iov, msg.msg_iov, sizeof(*msg.msg_iov)))
476 				return -EFAULT;
477 			sr->len = iomsg->fast_iov[0].iov_len;
478 			iomsg->free_iov = NULL;
479 		}
480 
481 		if (req->flags & REQ_F_APOLL_MULTISHOT) {
482 			iomsg->namelen = msg.msg_namelen;
483 			iomsg->controllen = msg.msg_controllen;
484 			if (io_recvmsg_multishot_overflow(iomsg))
485 				return -EOVERFLOW;
486 		}
487 	} else {
488 		iomsg->free_iov = iomsg->fast_iov;
489 		ret = __import_iovec(ITER_DEST, msg.msg_iov, msg.msg_iovlen, UIO_FASTIOV,
490 				     &iomsg->free_iov, &iomsg->msg.msg_iter,
491 				     false);
492 		if (ret > 0)
493 			ret = 0;
494 	}
495 
496 	return ret;
497 }
498 
499 #ifdef CONFIG_COMPAT
500 static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
501 					struct io_async_msghdr *iomsg)
502 {
503 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
504 	struct compat_msghdr msg;
505 	struct compat_iovec __user *uiov;
506 	int ret;
507 
508 	if (copy_from_user(&msg, sr->umsg_compat, sizeof(msg)))
509 		return -EFAULT;
510 
511 	ret = __get_compat_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
512 	if (ret)
513 		return ret;
514 
515 	uiov = compat_ptr(msg.msg_iov);
516 	if (req->flags & REQ_F_BUFFER_SELECT) {
517 		compat_ssize_t clen;
518 
519 		iomsg->free_iov = NULL;
520 		if (msg.msg_iovlen == 0) {
521 			sr->len = 0;
522 		} else if (msg.msg_iovlen > 1) {
523 			return -EINVAL;
524 		} else {
525 			if (!access_ok(uiov, sizeof(*uiov)))
526 				return -EFAULT;
527 			if (__get_user(clen, &uiov->iov_len))
528 				return -EFAULT;
529 			if (clen < 0)
530 				return -EINVAL;
531 			sr->len = clen;
532 		}
533 
534 		if (req->flags & REQ_F_APOLL_MULTISHOT) {
535 			iomsg->namelen = msg.msg_namelen;
536 			iomsg->controllen = msg.msg_controllen;
537 			if (io_recvmsg_multishot_overflow(iomsg))
538 				return -EOVERFLOW;
539 		}
540 	} else {
541 		iomsg->free_iov = iomsg->fast_iov;
542 		ret = __import_iovec(ITER_DEST, (struct iovec __user *)uiov, msg.msg_iovlen,
543 				   UIO_FASTIOV, &iomsg->free_iov,
544 				   &iomsg->msg.msg_iter, true);
545 		if (ret < 0)
546 			return ret;
547 	}
548 
549 	return 0;
550 }
551 #endif
552 
553 static int io_recvmsg_copy_hdr(struct io_kiocb *req,
554 			       struct io_async_msghdr *iomsg)
555 {
556 	iomsg->msg.msg_name = &iomsg->addr;
557 	iomsg->msg.msg_iter.nr_segs = 0;
558 
559 #ifdef CONFIG_COMPAT
560 	if (req->ctx->compat)
561 		return __io_compat_recvmsg_copy_hdr(req, iomsg);
562 #endif
563 
564 	return __io_recvmsg_copy_hdr(req, iomsg);
565 }
566 
567 int io_recvmsg_prep_async(struct io_kiocb *req)
568 {
569 	int ret;
570 
571 	if (!io_msg_alloc_async_prep(req))
572 		return -ENOMEM;
573 	ret = io_recvmsg_copy_hdr(req, req->async_data);
574 	if (!ret)
575 		req->flags |= REQ_F_NEED_CLEANUP;
576 	return ret;
577 }
578 
579 #define RECVMSG_FLAGS (IORING_RECVSEND_POLL_FIRST | IORING_RECV_MULTISHOT)
580 
581 int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
582 {
583 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
584 
585 	if (unlikely(sqe->file_index || sqe->addr2))
586 		return -EINVAL;
587 
588 	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
589 	sr->len = READ_ONCE(sqe->len);
590 	sr->flags = READ_ONCE(sqe->ioprio);
591 	if (sr->flags & ~(RECVMSG_FLAGS))
592 		return -EINVAL;
593 	sr->msg_flags = READ_ONCE(sqe->msg_flags);
594 	if (sr->msg_flags & MSG_DONTWAIT)
595 		req->flags |= REQ_F_NOWAIT;
596 	if (sr->msg_flags & MSG_ERRQUEUE)
597 		req->flags |= REQ_F_CLEAR_POLLIN;
598 	if (sr->flags & IORING_RECV_MULTISHOT) {
599 		if (!(req->flags & REQ_F_BUFFER_SELECT))
600 			return -EINVAL;
601 		if (sr->msg_flags & MSG_WAITALL)
602 			return -EINVAL;
603 		if (req->opcode == IORING_OP_RECV && sr->len)
604 			return -EINVAL;
605 		req->flags |= REQ_F_APOLL_MULTISHOT;
606 		/*
607 		 * Store the buffer group for this multishot receive separately,
608 		 * as if we end up doing an io-wq based issue that selects a
609 		 * buffer, it has to be committed immediately and that will
610 		 * clear ->buf_list. This means we lose the link to the buffer
611 		 * list, and the eventual buffer put on completion then cannot
612 		 * restore it.
613 		 */
614 		sr->buf_group = req->buf_index;
615 	}
616 
617 #ifdef CONFIG_COMPAT
618 	if (req->ctx->compat)
619 		sr->msg_flags |= MSG_CMSG_COMPAT;
620 #endif
621 	sr->done_io = 0;
622 	sr->nr_multishot_loops = 0;
623 	return 0;
624 }
625 
626 static inline void io_recv_prep_retry(struct io_kiocb *req)
627 {
628 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
629 
630 	sr->done_io = 0;
631 	sr->len = 0; /* get from the provided buffer */
632 	req->buf_index = sr->buf_group;
633 }
634 
635 /*
636  * Finishes io_recv and io_recvmsg.
637  *
638  * Returns true if it is actually finished, or false if it should run
639  * again (for multishot).
640  */
641 static inline bool io_recv_finish(struct io_kiocb *req, int *ret,
642 				  struct msghdr *msg, bool mshot_finished,
643 				  unsigned issue_flags)
644 {
645 	unsigned int cflags;
646 
647 	cflags = io_put_kbuf(req, issue_flags);
648 	if (msg->msg_inq && msg->msg_inq != -1)
649 		cflags |= IORING_CQE_F_SOCK_NONEMPTY;
650 
651 	if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
652 		io_req_set_res(req, *ret, cflags);
653 		*ret = IOU_OK;
654 		return true;
655 	}
656 
657 	if (mshot_finished)
658 		goto finish;
659 
660 	/*
661 	 * Fill CQE for this receive and see if we should keep trying to
662 	 * receive from this socket.
663 	 */
664 	if (io_fill_cqe_req_aux(req, issue_flags & IO_URING_F_COMPLETE_DEFER,
665 				*ret, cflags | IORING_CQE_F_MORE)) {
666 		struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
667 		int mshot_retry_ret = IOU_ISSUE_SKIP_COMPLETE;
668 
669 		io_recv_prep_retry(req);
670 		/* Known not-empty or unknown state, retry */
671 		if (cflags & IORING_CQE_F_SOCK_NONEMPTY || msg->msg_inq == -1) {
672 			if (sr->nr_multishot_loops++ < MULTISHOT_MAX_RETRY)
673 				return false;
674 			/* mshot retries exceeded, force a requeue */
675 			sr->nr_multishot_loops = 0;
676 			mshot_retry_ret = IOU_REQUEUE;
677 		}
678 		if (issue_flags & IO_URING_F_MULTISHOT)
679 			*ret = mshot_retry_ret;
680 		else
681 			*ret = -EAGAIN;
682 		return true;
683 	}
684 	/* Otherwise stop multishot but use the current result. */
685 finish:
686 	io_req_set_res(req, *ret, cflags);
687 
688 	if (issue_flags & IO_URING_F_MULTISHOT)
689 		*ret = IOU_STOP_MULTISHOT;
690 	else
691 		*ret = IOU_OK;
692 	return true;
693 }
694 
695 static int io_recvmsg_prep_multishot(struct io_async_msghdr *kmsg,
696 				     struct io_sr_msg *sr, void __user **buf,
697 				     size_t *len)
698 {
699 	unsigned long ubuf = (unsigned long) *buf;
700 	unsigned long hdr;
701 
702 	hdr = sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
703 		kmsg->controllen;
704 	if (*len < hdr)
705 		return -EFAULT;
706 
707 	if (kmsg->controllen) {
708 		unsigned long control = ubuf + hdr - kmsg->controllen;
709 
710 		kmsg->msg.msg_control_user = (void __user *) control;
711 		kmsg->msg.msg_controllen = kmsg->controllen;
712 	}
713 
714 	sr->buf = *buf; /* stash for later copy */
715 	*buf = (void __user *) (ubuf + hdr);
716 	kmsg->payloadlen = *len = *len - hdr;
717 	return 0;
718 }
719 
720 struct io_recvmsg_multishot_hdr {
721 	struct io_uring_recvmsg_out msg;
722 	struct sockaddr_storage addr;
723 };
724 
725 static int io_recvmsg_multishot(struct socket *sock, struct io_sr_msg *io,
726 				struct io_async_msghdr *kmsg,
727 				unsigned int flags, bool *finished)
728 {
729 	int err;
730 	int copy_len;
731 	struct io_recvmsg_multishot_hdr hdr;
732 
733 	if (kmsg->namelen)
734 		kmsg->msg.msg_name = &hdr.addr;
735 	kmsg->msg.msg_flags = flags & (MSG_CMSG_CLOEXEC|MSG_CMSG_COMPAT);
736 	kmsg->msg.msg_namelen = 0;
737 
738 	if (sock->file->f_flags & O_NONBLOCK)
739 		flags |= MSG_DONTWAIT;
740 
741 	err = sock_recvmsg(sock, &kmsg->msg, flags);
742 	*finished = err <= 0;
743 	if (err < 0)
744 		return err;
745 
746 	hdr.msg = (struct io_uring_recvmsg_out) {
747 		.controllen = kmsg->controllen - kmsg->msg.msg_controllen,
748 		.flags = kmsg->msg.msg_flags & ~MSG_CMSG_COMPAT
749 	};
750 
751 	hdr.msg.payloadlen = err;
752 	if (err > kmsg->payloadlen)
753 		err = kmsg->payloadlen;
754 
755 	copy_len = sizeof(struct io_uring_recvmsg_out);
756 	if (kmsg->msg.msg_namelen > kmsg->namelen)
757 		copy_len += kmsg->namelen;
758 	else
759 		copy_len += kmsg->msg.msg_namelen;
760 
761 	/*
762 	 *      "fromlen shall refer to the value before truncation.."
763 	 *                      1003.1g
764 	 */
765 	hdr.msg.namelen = kmsg->msg.msg_namelen;
766 
767 	/* ensure that there is no gap between hdr and sockaddr_storage */
768 	BUILD_BUG_ON(offsetof(struct io_recvmsg_multishot_hdr, addr) !=
769 		     sizeof(struct io_uring_recvmsg_out));
770 	if (copy_to_user(io->buf, &hdr, copy_len)) {
771 		*finished = true;
772 		return -EFAULT;
773 	}
774 
775 	return sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
776 			kmsg->controllen + err;
777 }
778 
779 int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
780 {
781 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
782 	struct io_async_msghdr iomsg, *kmsg;
783 	struct socket *sock;
784 	unsigned flags;
785 	int ret, min_ret = 0;
786 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
787 	bool mshot_finished = true;
788 
789 	sock = sock_from_file(req->file);
790 	if (unlikely(!sock))
791 		return -ENOTSOCK;
792 
793 	if (req_has_async_data(req)) {
794 		kmsg = req->async_data;
795 	} else {
796 		ret = io_recvmsg_copy_hdr(req, &iomsg);
797 		if (ret)
798 			return ret;
799 		kmsg = &iomsg;
800 	}
801 
802 	if (!(req->flags & REQ_F_POLLED) &&
803 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
804 		return io_setup_async_msg(req, kmsg, issue_flags);
805 
806 	if (!io_check_multishot(req, issue_flags))
807 		return io_setup_async_msg(req, kmsg, issue_flags);
808 
809 retry_multishot:
810 	if (io_do_buffer_select(req)) {
811 		void __user *buf;
812 		size_t len = sr->len;
813 
814 		buf = io_buffer_select(req, &len, issue_flags);
815 		if (!buf)
816 			return -ENOBUFS;
817 
818 		if (req->flags & REQ_F_APOLL_MULTISHOT) {
819 			ret = io_recvmsg_prep_multishot(kmsg, sr, &buf, &len);
820 			if (ret) {
821 				io_kbuf_recycle(req, issue_flags);
822 				return ret;
823 			}
824 		}
825 
826 		iov_iter_ubuf(&kmsg->msg.msg_iter, ITER_DEST, buf, len);
827 	}
828 
829 	flags = sr->msg_flags;
830 	if (force_nonblock)
831 		flags |= MSG_DONTWAIT;
832 
833 	kmsg->msg.msg_get_inq = 1;
834 	kmsg->msg.msg_inq = -1;
835 	if (req->flags & REQ_F_APOLL_MULTISHOT) {
836 		ret = io_recvmsg_multishot(sock, sr, kmsg, flags,
837 					   &mshot_finished);
838 	} else {
839 		/* disable partial retry for recvmsg with cmsg attached */
840 		if (flags & MSG_WAITALL && !kmsg->msg.msg_controllen)
841 			min_ret = iov_iter_count(&kmsg->msg.msg_iter);
842 
843 		ret = __sys_recvmsg_sock(sock, &kmsg->msg, sr->umsg,
844 					 kmsg->uaddr, flags);
845 	}
846 
847 	if (ret < min_ret) {
848 		if (ret == -EAGAIN && force_nonblock) {
849 			ret = io_setup_async_msg(req, kmsg, issue_flags);
850 			if (ret == -EAGAIN && (issue_flags & IO_URING_F_MULTISHOT)) {
851 				io_kbuf_recycle(req, issue_flags);
852 				return IOU_ISSUE_SKIP_COMPLETE;
853 			}
854 			return ret;
855 		}
856 		if (ret > 0 && io_net_retry(sock, flags)) {
857 			sr->done_io += ret;
858 			req->flags |= REQ_F_PARTIAL_IO;
859 			return io_setup_async_msg(req, kmsg, issue_flags);
860 		}
861 		if (ret == -ERESTARTSYS)
862 			ret = -EINTR;
863 		req_set_fail(req);
864 	} else if ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
865 		req_set_fail(req);
866 	}
867 
868 	if (ret > 0)
869 		ret += sr->done_io;
870 	else if (sr->done_io)
871 		ret = sr->done_io;
872 	else
873 		io_kbuf_recycle(req, issue_flags);
874 
875 	if (!io_recv_finish(req, &ret, &kmsg->msg, mshot_finished, issue_flags))
876 		goto retry_multishot;
877 
878 	if (mshot_finished) {
879 		/* fast path, check for non-NULL to avoid function call */
880 		if (kmsg->free_iov)
881 			kfree(kmsg->free_iov);
882 		io_netmsg_recycle(req, issue_flags);
883 		req->flags &= ~REQ_F_NEED_CLEANUP;
884 	}
885 
886 	return ret;
887 }
888 
889 int io_recv(struct io_kiocb *req, unsigned int issue_flags)
890 {
891 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
892 	struct msghdr msg;
893 	struct socket *sock;
894 	unsigned flags;
895 	int ret, min_ret = 0;
896 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
897 	size_t len = sr->len;
898 
899 	if (!(req->flags & REQ_F_POLLED) &&
900 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
901 		return -EAGAIN;
902 
903 	if (!io_check_multishot(req, issue_flags))
904 		return -EAGAIN;
905 
906 	sock = sock_from_file(req->file);
907 	if (unlikely(!sock))
908 		return -ENOTSOCK;
909 
910 	msg.msg_name = NULL;
911 	msg.msg_namelen = 0;
912 	msg.msg_control = NULL;
913 	msg.msg_get_inq = 1;
914 	msg.msg_controllen = 0;
915 	msg.msg_iocb = NULL;
916 	msg.msg_ubuf = NULL;
917 
918 retry_multishot:
919 	if (io_do_buffer_select(req)) {
920 		void __user *buf;
921 
922 		buf = io_buffer_select(req, &len, issue_flags);
923 		if (!buf)
924 			return -ENOBUFS;
925 		sr->buf = buf;
926 		sr->len = len;
927 	}
928 
929 	ret = import_ubuf(ITER_DEST, sr->buf, len, &msg.msg_iter);
930 	if (unlikely(ret))
931 		goto out_free;
932 
933 	msg.msg_inq = -1;
934 	msg.msg_flags = 0;
935 
936 	flags = sr->msg_flags;
937 	if (force_nonblock)
938 		flags |= MSG_DONTWAIT;
939 	if (flags & MSG_WAITALL)
940 		min_ret = iov_iter_count(&msg.msg_iter);
941 
942 	ret = sock_recvmsg(sock, &msg, flags);
943 	if (ret < min_ret) {
944 		if (ret == -EAGAIN && force_nonblock) {
945 			if (issue_flags & IO_URING_F_MULTISHOT) {
946 				io_kbuf_recycle(req, issue_flags);
947 				return IOU_ISSUE_SKIP_COMPLETE;
948 			}
949 
950 			return -EAGAIN;
951 		}
952 		if (ret > 0 && io_net_retry(sock, flags)) {
953 			sr->len -= ret;
954 			sr->buf += ret;
955 			sr->done_io += ret;
956 			req->flags |= REQ_F_PARTIAL_IO;
957 			return -EAGAIN;
958 		}
959 		if (ret == -ERESTARTSYS)
960 			ret = -EINTR;
961 		req_set_fail(req);
962 	} else if ((flags & MSG_WAITALL) && (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
963 out_free:
964 		req_set_fail(req);
965 	}
966 
967 	if (ret > 0)
968 		ret += sr->done_io;
969 	else if (sr->done_io)
970 		ret = sr->done_io;
971 	else
972 		io_kbuf_recycle(req, issue_flags);
973 
974 	if (!io_recv_finish(req, &ret, &msg, ret <= 0, issue_flags))
975 		goto retry_multishot;
976 
977 	return ret;
978 }
979 
980 void io_send_zc_cleanup(struct io_kiocb *req)
981 {
982 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
983 	struct io_async_msghdr *io;
984 
985 	if (req_has_async_data(req)) {
986 		io = req->async_data;
987 		/* might be ->fast_iov if *msg_copy_hdr failed */
988 		if (io->free_iov != io->fast_iov)
989 			kfree(io->free_iov);
990 	}
991 	if (zc->notif) {
992 		io_notif_flush(zc->notif);
993 		zc->notif = NULL;
994 	}
995 }
996 
997 #define IO_ZC_FLAGS_COMMON (IORING_RECVSEND_POLL_FIRST | IORING_RECVSEND_FIXED_BUF)
998 #define IO_ZC_FLAGS_VALID  (IO_ZC_FLAGS_COMMON | IORING_SEND_ZC_REPORT_USAGE)
999 
1000 int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1001 {
1002 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
1003 	struct io_ring_ctx *ctx = req->ctx;
1004 	struct io_kiocb *notif;
1005 
1006 	if (unlikely(READ_ONCE(sqe->__pad2[0]) || READ_ONCE(sqe->addr3)))
1007 		return -EINVAL;
1008 	/* we don't support IOSQE_CQE_SKIP_SUCCESS just yet */
1009 	if (req->flags & REQ_F_CQE_SKIP)
1010 		return -EINVAL;
1011 
1012 	notif = zc->notif = io_alloc_notif(ctx);
1013 	if (!notif)
1014 		return -ENOMEM;
1015 	notif->cqe.user_data = req->cqe.user_data;
1016 	notif->cqe.res = 0;
1017 	notif->cqe.flags = IORING_CQE_F_NOTIF;
1018 	req->flags |= REQ_F_NEED_CLEANUP;
1019 
1020 	zc->flags = READ_ONCE(sqe->ioprio);
1021 	if (unlikely(zc->flags & ~IO_ZC_FLAGS_COMMON)) {
1022 		if (zc->flags & ~IO_ZC_FLAGS_VALID)
1023 			return -EINVAL;
1024 		if (zc->flags & IORING_SEND_ZC_REPORT_USAGE) {
1025 			io_notif_set_extended(notif);
1026 			io_notif_to_data(notif)->zc_report = true;
1027 		}
1028 	}
1029 
1030 	if (zc->flags & IORING_RECVSEND_FIXED_BUF) {
1031 		unsigned idx = READ_ONCE(sqe->buf_index);
1032 
1033 		if (unlikely(idx >= ctx->nr_user_bufs))
1034 			return -EFAULT;
1035 		idx = array_index_nospec(idx, ctx->nr_user_bufs);
1036 		req->imu = READ_ONCE(ctx->user_bufs[idx]);
1037 		io_req_set_rsrc_node(notif, ctx, 0);
1038 	}
1039 
1040 	if (req->opcode == IORING_OP_SEND_ZC) {
1041 		if (READ_ONCE(sqe->__pad3[0]))
1042 			return -EINVAL;
1043 		zc->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
1044 		zc->addr_len = READ_ONCE(sqe->addr_len);
1045 	} else {
1046 		if (unlikely(sqe->addr2 || sqe->file_index))
1047 			return -EINVAL;
1048 		if (unlikely(zc->flags & IORING_RECVSEND_FIXED_BUF))
1049 			return -EINVAL;
1050 	}
1051 
1052 	zc->buf = u64_to_user_ptr(READ_ONCE(sqe->addr));
1053 	zc->len = READ_ONCE(sqe->len);
1054 	zc->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
1055 	if (zc->msg_flags & MSG_DONTWAIT)
1056 		req->flags |= REQ_F_NOWAIT;
1057 
1058 	zc->done_io = 0;
1059 
1060 #ifdef CONFIG_COMPAT
1061 	if (req->ctx->compat)
1062 		zc->msg_flags |= MSG_CMSG_COMPAT;
1063 #endif
1064 	return 0;
1065 }
1066 
1067 static int io_sg_from_iter_iovec(struct sock *sk, struct sk_buff *skb,
1068 				 struct iov_iter *from, size_t length)
1069 {
1070 	skb_zcopy_downgrade_managed(skb);
1071 	return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
1072 }
1073 
1074 static int io_sg_from_iter(struct sock *sk, struct sk_buff *skb,
1075 			   struct iov_iter *from, size_t length)
1076 {
1077 	struct skb_shared_info *shinfo = skb_shinfo(skb);
1078 	int frag = shinfo->nr_frags;
1079 	int ret = 0;
1080 	struct bvec_iter bi;
1081 	ssize_t copied = 0;
1082 	unsigned long truesize = 0;
1083 
1084 	if (!frag)
1085 		shinfo->flags |= SKBFL_MANAGED_FRAG_REFS;
1086 	else if (unlikely(!skb_zcopy_managed(skb)))
1087 		return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
1088 
1089 	bi.bi_size = min(from->count, length);
1090 	bi.bi_bvec_done = from->iov_offset;
1091 	bi.bi_idx = 0;
1092 
1093 	while (bi.bi_size && frag < MAX_SKB_FRAGS) {
1094 		struct bio_vec v = mp_bvec_iter_bvec(from->bvec, bi);
1095 
1096 		copied += v.bv_len;
1097 		truesize += PAGE_ALIGN(v.bv_len + v.bv_offset);
1098 		__skb_fill_page_desc_noacc(shinfo, frag++, v.bv_page,
1099 					   v.bv_offset, v.bv_len);
1100 		bvec_iter_advance_single(from->bvec, &bi, v.bv_len);
1101 	}
1102 	if (bi.bi_size)
1103 		ret = -EMSGSIZE;
1104 
1105 	shinfo->nr_frags = frag;
1106 	from->bvec += bi.bi_idx;
1107 	from->nr_segs -= bi.bi_idx;
1108 	from->count -= copied;
1109 	from->iov_offset = bi.bi_bvec_done;
1110 
1111 	skb->data_len += copied;
1112 	skb->len += copied;
1113 	skb->truesize += truesize;
1114 
1115 	if (sk && sk->sk_type == SOCK_STREAM) {
1116 		sk_wmem_queued_add(sk, truesize);
1117 		if (!skb_zcopy_pure(skb))
1118 			sk_mem_charge(sk, truesize);
1119 	} else {
1120 		refcount_add(truesize, &skb->sk->sk_wmem_alloc);
1121 	}
1122 	return ret;
1123 }
1124 
1125 int io_send_zc(struct io_kiocb *req, unsigned int issue_flags)
1126 {
1127 	struct sockaddr_storage __address;
1128 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
1129 	struct msghdr msg;
1130 	struct socket *sock;
1131 	unsigned msg_flags;
1132 	int ret, min_ret = 0;
1133 
1134 	sock = sock_from_file(req->file);
1135 	if (unlikely(!sock))
1136 		return -ENOTSOCK;
1137 	if (!test_bit(SOCK_SUPPORT_ZC, &sock->flags))
1138 		return -EOPNOTSUPP;
1139 
1140 	msg.msg_name = NULL;
1141 	msg.msg_control = NULL;
1142 	msg.msg_controllen = 0;
1143 	msg.msg_namelen = 0;
1144 
1145 	if (zc->addr) {
1146 		if (req_has_async_data(req)) {
1147 			struct io_async_msghdr *io = req->async_data;
1148 
1149 			msg.msg_name = &io->addr;
1150 		} else {
1151 			ret = move_addr_to_kernel(zc->addr, zc->addr_len, &__address);
1152 			if (unlikely(ret < 0))
1153 				return ret;
1154 			msg.msg_name = (struct sockaddr *)&__address;
1155 		}
1156 		msg.msg_namelen = zc->addr_len;
1157 	}
1158 
1159 	if (!(req->flags & REQ_F_POLLED) &&
1160 	    (zc->flags & IORING_RECVSEND_POLL_FIRST))
1161 		return io_setup_async_addr(req, &__address, issue_flags);
1162 
1163 	if (zc->flags & IORING_RECVSEND_FIXED_BUF) {
1164 		ret = io_import_fixed(ITER_SOURCE, &msg.msg_iter, req->imu,
1165 					(u64)(uintptr_t)zc->buf, zc->len);
1166 		if (unlikely(ret))
1167 			return ret;
1168 		msg.sg_from_iter = io_sg_from_iter;
1169 	} else {
1170 		io_notif_set_extended(zc->notif);
1171 		ret = import_ubuf(ITER_SOURCE, zc->buf, zc->len, &msg.msg_iter);
1172 		if (unlikely(ret))
1173 			return ret;
1174 		ret = io_notif_account_mem(zc->notif, zc->len);
1175 		if (unlikely(ret))
1176 			return ret;
1177 		msg.sg_from_iter = io_sg_from_iter_iovec;
1178 	}
1179 
1180 	msg_flags = zc->msg_flags | MSG_ZEROCOPY;
1181 	if (issue_flags & IO_URING_F_NONBLOCK)
1182 		msg_flags |= MSG_DONTWAIT;
1183 	if (msg_flags & MSG_WAITALL)
1184 		min_ret = iov_iter_count(&msg.msg_iter);
1185 	msg_flags &= ~MSG_INTERNAL_SENDMSG_FLAGS;
1186 
1187 	msg.msg_flags = msg_flags;
1188 	msg.msg_ubuf = &io_notif_to_data(zc->notif)->uarg;
1189 	ret = sock_sendmsg(sock, &msg);
1190 
1191 	if (unlikely(ret < min_ret)) {
1192 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1193 			return io_setup_async_addr(req, &__address, issue_flags);
1194 
1195 		if (ret > 0 && io_net_retry(sock, msg.msg_flags)) {
1196 			zc->len -= ret;
1197 			zc->buf += ret;
1198 			zc->done_io += ret;
1199 			req->flags |= REQ_F_PARTIAL_IO;
1200 			return io_setup_async_addr(req, &__address, issue_flags);
1201 		}
1202 		if (ret == -ERESTARTSYS)
1203 			ret = -EINTR;
1204 		req_set_fail(req);
1205 	}
1206 
1207 	if (ret >= 0)
1208 		ret += zc->done_io;
1209 	else if (zc->done_io)
1210 		ret = zc->done_io;
1211 
1212 	/*
1213 	 * If we're in io-wq we can't rely on tw ordering guarantees, defer
1214 	 * flushing notif to io_send_zc_cleanup()
1215 	 */
1216 	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
1217 		io_notif_flush(zc->notif);
1218 		req->flags &= ~REQ_F_NEED_CLEANUP;
1219 	}
1220 	io_req_set_res(req, ret, IORING_CQE_F_MORE);
1221 	return IOU_OK;
1222 }
1223 
1224 int io_sendmsg_zc(struct io_kiocb *req, unsigned int issue_flags)
1225 {
1226 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
1227 	struct io_async_msghdr iomsg, *kmsg;
1228 	struct socket *sock;
1229 	unsigned flags;
1230 	int ret, min_ret = 0;
1231 
1232 	io_notif_set_extended(sr->notif);
1233 
1234 	sock = sock_from_file(req->file);
1235 	if (unlikely(!sock))
1236 		return -ENOTSOCK;
1237 	if (!test_bit(SOCK_SUPPORT_ZC, &sock->flags))
1238 		return -EOPNOTSUPP;
1239 
1240 	if (req_has_async_data(req)) {
1241 		kmsg = req->async_data;
1242 	} else {
1243 		ret = io_sendmsg_copy_hdr(req, &iomsg);
1244 		if (ret)
1245 			return ret;
1246 		kmsg = &iomsg;
1247 	}
1248 
1249 	if (!(req->flags & REQ_F_POLLED) &&
1250 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
1251 		return io_setup_async_msg(req, kmsg, issue_flags);
1252 
1253 	flags = sr->msg_flags | MSG_ZEROCOPY;
1254 	if (issue_flags & IO_URING_F_NONBLOCK)
1255 		flags |= MSG_DONTWAIT;
1256 	if (flags & MSG_WAITALL)
1257 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
1258 
1259 	kmsg->msg.msg_ubuf = &io_notif_to_data(sr->notif)->uarg;
1260 	kmsg->msg.sg_from_iter = io_sg_from_iter_iovec;
1261 	ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
1262 
1263 	if (unlikely(ret < min_ret)) {
1264 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1265 			return io_setup_async_msg(req, kmsg, issue_flags);
1266 
1267 		if (ret > 0 && io_net_retry(sock, flags)) {
1268 			sr->done_io += ret;
1269 			req->flags |= REQ_F_PARTIAL_IO;
1270 			return io_setup_async_msg(req, kmsg, issue_flags);
1271 		}
1272 		if (ret == -ERESTARTSYS)
1273 			ret = -EINTR;
1274 		req_set_fail(req);
1275 	}
1276 	/* fast path, check for non-NULL to avoid function call */
1277 	if (kmsg->free_iov) {
1278 		kfree(kmsg->free_iov);
1279 		kmsg->free_iov = NULL;
1280 	}
1281 
1282 	io_netmsg_recycle(req, issue_flags);
1283 	if (ret >= 0)
1284 		ret += sr->done_io;
1285 	else if (sr->done_io)
1286 		ret = sr->done_io;
1287 
1288 	/*
1289 	 * If we're in io-wq we can't rely on tw ordering guarantees, defer
1290 	 * flushing notif to io_send_zc_cleanup()
1291 	 */
1292 	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
1293 		io_notif_flush(sr->notif);
1294 		req->flags &= ~REQ_F_NEED_CLEANUP;
1295 	}
1296 	io_req_set_res(req, ret, IORING_CQE_F_MORE);
1297 	return IOU_OK;
1298 }
1299 
1300 void io_sendrecv_fail(struct io_kiocb *req)
1301 {
1302 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
1303 
1304 	if (req->flags & REQ_F_PARTIAL_IO)
1305 		req->cqe.res = sr->done_io;
1306 
1307 	if ((req->flags & REQ_F_NEED_CLEANUP) &&
1308 	    (req->opcode == IORING_OP_SEND_ZC || req->opcode == IORING_OP_SENDMSG_ZC))
1309 		req->cqe.flags |= IORING_CQE_F_MORE;
1310 }
1311 
1312 int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1313 {
1314 	struct io_accept *accept = io_kiocb_to_cmd(req, struct io_accept);
1315 	unsigned flags;
1316 
1317 	if (sqe->len || sqe->buf_index)
1318 		return -EINVAL;
1319 
1320 	accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
1321 	accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2));
1322 	accept->flags = READ_ONCE(sqe->accept_flags);
1323 	accept->nofile = rlimit(RLIMIT_NOFILE);
1324 	flags = READ_ONCE(sqe->ioprio);
1325 	if (flags & ~IORING_ACCEPT_MULTISHOT)
1326 		return -EINVAL;
1327 
1328 	accept->file_slot = READ_ONCE(sqe->file_index);
1329 	if (accept->file_slot) {
1330 		if (accept->flags & SOCK_CLOEXEC)
1331 			return -EINVAL;
1332 		if (flags & IORING_ACCEPT_MULTISHOT &&
1333 		    accept->file_slot != IORING_FILE_INDEX_ALLOC)
1334 			return -EINVAL;
1335 	}
1336 	if (accept->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
1337 		return -EINVAL;
1338 	if (SOCK_NONBLOCK != O_NONBLOCK && (accept->flags & SOCK_NONBLOCK))
1339 		accept->flags = (accept->flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
1340 	if (flags & IORING_ACCEPT_MULTISHOT)
1341 		req->flags |= REQ_F_APOLL_MULTISHOT;
1342 	return 0;
1343 }
1344 
1345 int io_accept(struct io_kiocb *req, unsigned int issue_flags)
1346 {
1347 	struct io_accept *accept = io_kiocb_to_cmd(req, struct io_accept);
1348 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
1349 	unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0;
1350 	bool fixed = !!accept->file_slot;
1351 	struct file *file;
1352 	int ret, fd;
1353 
1354 	if (!io_check_multishot(req, issue_flags))
1355 		return -EAGAIN;
1356 retry:
1357 	if (!fixed) {
1358 		fd = __get_unused_fd_flags(accept->flags, accept->nofile);
1359 		if (unlikely(fd < 0))
1360 			return fd;
1361 	}
1362 	file = do_accept(req->file, file_flags, accept->addr, accept->addr_len,
1363 			 accept->flags);
1364 	if (IS_ERR(file)) {
1365 		if (!fixed)
1366 			put_unused_fd(fd);
1367 		ret = PTR_ERR(file);
1368 		if (ret == -EAGAIN && force_nonblock) {
1369 			/*
1370 			 * if it's multishot and polled, we don't need to
1371 			 * return EAGAIN to arm the poll infra since it
1372 			 * has already been done
1373 			 */
1374 			if (issue_flags & IO_URING_F_MULTISHOT)
1375 				return IOU_ISSUE_SKIP_COMPLETE;
1376 			return ret;
1377 		}
1378 		if (ret == -ERESTARTSYS)
1379 			ret = -EINTR;
1380 		req_set_fail(req);
1381 	} else if (!fixed) {
1382 		fd_install(fd, file);
1383 		ret = fd;
1384 	} else {
1385 		ret = io_fixed_fd_install(req, issue_flags, file,
1386 						accept->file_slot);
1387 	}
1388 
1389 	if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
1390 		io_req_set_res(req, ret, 0);
1391 		return IOU_OK;
1392 	}
1393 
1394 	if (ret < 0)
1395 		return ret;
1396 	if (io_fill_cqe_req_aux(req, issue_flags & IO_URING_F_COMPLETE_DEFER,
1397 				ret, IORING_CQE_F_MORE))
1398 		goto retry;
1399 
1400 	io_req_set_res(req, ret, 0);
1401 	return IOU_STOP_MULTISHOT;
1402 }
1403 
1404 int io_socket_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1405 {
1406 	struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
1407 
1408 	if (sqe->addr || sqe->rw_flags || sqe->buf_index)
1409 		return -EINVAL;
1410 
1411 	sock->domain = READ_ONCE(sqe->fd);
1412 	sock->type = READ_ONCE(sqe->off);
1413 	sock->protocol = READ_ONCE(sqe->len);
1414 	sock->file_slot = READ_ONCE(sqe->file_index);
1415 	sock->nofile = rlimit(RLIMIT_NOFILE);
1416 
1417 	sock->flags = sock->type & ~SOCK_TYPE_MASK;
1418 	if (sock->file_slot && (sock->flags & SOCK_CLOEXEC))
1419 		return -EINVAL;
1420 	if (sock->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
1421 		return -EINVAL;
1422 	return 0;
1423 }
1424 
1425 int io_socket(struct io_kiocb *req, unsigned int issue_flags)
1426 {
1427 	struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
1428 	bool fixed = !!sock->file_slot;
1429 	struct file *file;
1430 	int ret, fd;
1431 
1432 	if (!fixed) {
1433 		fd = __get_unused_fd_flags(sock->flags, sock->nofile);
1434 		if (unlikely(fd < 0))
1435 			return fd;
1436 	}
1437 	file = __sys_socket_file(sock->domain, sock->type, sock->protocol);
1438 	if (IS_ERR(file)) {
1439 		if (!fixed)
1440 			put_unused_fd(fd);
1441 		ret = PTR_ERR(file);
1442 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1443 			return -EAGAIN;
1444 		if (ret == -ERESTARTSYS)
1445 			ret = -EINTR;
1446 		req_set_fail(req);
1447 	} else if (!fixed) {
1448 		fd_install(fd, file);
1449 		ret = fd;
1450 	} else {
1451 		ret = io_fixed_fd_install(req, issue_flags, file,
1452 					    sock->file_slot);
1453 	}
1454 	io_req_set_res(req, ret, 0);
1455 	return IOU_OK;
1456 }
1457 
1458 int io_connect_prep_async(struct io_kiocb *req)
1459 {
1460 	struct io_async_connect *io = req->async_data;
1461 	struct io_connect *conn = io_kiocb_to_cmd(req, struct io_connect);
1462 
1463 	return move_addr_to_kernel(conn->addr, conn->addr_len, &io->address);
1464 }
1465 
1466 int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1467 {
1468 	struct io_connect *conn = io_kiocb_to_cmd(req, struct io_connect);
1469 
1470 	if (sqe->len || sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in)
1471 		return -EINVAL;
1472 
1473 	conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
1474 	conn->addr_len =  READ_ONCE(sqe->addr2);
1475 	conn->in_progress = conn->seen_econnaborted = false;
1476 	return 0;
1477 }
1478 
1479 int io_connect(struct io_kiocb *req, unsigned int issue_flags)
1480 {
1481 	struct io_connect *connect = io_kiocb_to_cmd(req, struct io_connect);
1482 	struct io_async_connect __io, *io;
1483 	unsigned file_flags;
1484 	int ret;
1485 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
1486 
1487 	if (req_has_async_data(req)) {
1488 		io = req->async_data;
1489 	} else {
1490 		ret = move_addr_to_kernel(connect->addr,
1491 						connect->addr_len,
1492 						&__io.address);
1493 		if (ret)
1494 			goto out;
1495 		io = &__io;
1496 	}
1497 
1498 	file_flags = force_nonblock ? O_NONBLOCK : 0;
1499 
1500 	ret = __sys_connect_file(req->file, &io->address,
1501 					connect->addr_len, file_flags);
1502 	if ((ret == -EAGAIN || ret == -EINPROGRESS || ret == -ECONNABORTED)
1503 	    && force_nonblock) {
1504 		if (ret == -EINPROGRESS) {
1505 			connect->in_progress = true;
1506 		} else if (ret == -ECONNABORTED) {
1507 			if (connect->seen_econnaborted)
1508 				goto out;
1509 			connect->seen_econnaborted = true;
1510 		}
1511 		if (req_has_async_data(req))
1512 			return -EAGAIN;
1513 		if (io_alloc_async_data(req)) {
1514 			ret = -ENOMEM;
1515 			goto out;
1516 		}
1517 		memcpy(req->async_data, &__io, sizeof(__io));
1518 		return -EAGAIN;
1519 	}
1520 	if (connect->in_progress) {
1521 		/*
1522 		 * At least bluetooth will return -EBADFD on a re-connect
1523 		 * attempt, and it's (supposedly) also valid to get -EISCONN
1524 		 * which means the previous result is good. For both of these,
1525 		 * grab the sock_error() and use that for the completion.
1526 		 */
1527 		if (ret == -EBADFD || ret == -EISCONN)
1528 			ret = sock_error(sock_from_file(req->file)->sk);
1529 	}
1530 	if (ret == -ERESTARTSYS)
1531 		ret = -EINTR;
1532 out:
1533 	if (ret < 0)
1534 		req_set_fail(req);
1535 	io_req_set_res(req, ret, 0);
1536 	return IOU_OK;
1537 }
1538 
1539 void io_netmsg_cache_free(struct io_cache_entry *entry)
1540 {
1541 	kfree(container_of(entry, struct io_async_msghdr, cache));
1542 }
1543 #endif
1544