xref: /linux/io_uring/net.c (revision 332d2c1d713e232e163386c35a3ba0c1b90df83f)
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 	int				iou_flags;
32 	u32				file_slot;
33 	unsigned long			nofile;
34 };
35 
36 struct io_socket {
37 	struct file			*file;
38 	int				domain;
39 	int				type;
40 	int				protocol;
41 	int				flags;
42 	u32				file_slot;
43 	unsigned long			nofile;
44 };
45 
46 struct io_connect {
47 	struct file			*file;
48 	struct sockaddr __user		*addr;
49 	int				addr_len;
50 	bool				in_progress;
51 	bool				seen_econnaborted;
52 };
53 
54 struct io_sr_msg {
55 	struct file			*file;
56 	union {
57 		struct compat_msghdr __user	*umsg_compat;
58 		struct user_msghdr __user	*umsg;
59 		void __user			*buf;
60 	};
61 	int				len;
62 	unsigned			done_io;
63 	unsigned			msg_flags;
64 	unsigned			nr_multishot_loops;
65 	u16				flags;
66 	/* initialised and used only by !msg send variants */
67 	u16				addr_len;
68 	u16				buf_group;
69 	void __user			*addr;
70 	void __user			*msg_control;
71 	/* used only for send zerocopy */
72 	struct io_kiocb 		*notif;
73 };
74 
75 /*
76  * Number of times we'll try and do receives if there's more data. If we
77  * exceed this limit, then add us to the back of the queue and retry from
78  * there. This helps fairness between flooding clients.
79  */
80 #define MULTISHOT_MAX_RETRY	32
81 
82 int io_shutdown_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
83 {
84 	struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
85 
86 	if (unlikely(sqe->off || sqe->addr || sqe->rw_flags ||
87 		     sqe->buf_index || sqe->splice_fd_in))
88 		return -EINVAL;
89 
90 	shutdown->how = READ_ONCE(sqe->len);
91 	req->flags |= REQ_F_FORCE_ASYNC;
92 	return 0;
93 }
94 
95 int io_shutdown(struct io_kiocb *req, unsigned int issue_flags)
96 {
97 	struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
98 	struct socket *sock;
99 	int ret;
100 
101 	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
102 
103 	sock = sock_from_file(req->file);
104 	if (unlikely(!sock))
105 		return -ENOTSOCK;
106 
107 	ret = __sys_shutdown_sock(sock, shutdown->how);
108 	io_req_set_res(req, ret, 0);
109 	return IOU_OK;
110 }
111 
112 static bool io_net_retry(struct socket *sock, int flags)
113 {
114 	if (!(flags & MSG_WAITALL))
115 		return false;
116 	return sock->type == SOCK_STREAM || sock->type == SOCK_SEQPACKET;
117 }
118 
119 static void io_netmsg_iovec_free(struct io_async_msghdr *kmsg)
120 {
121 	if (kmsg->free_iov) {
122 		kfree(kmsg->free_iov);
123 		kmsg->free_iov_nr = 0;
124 		kmsg->free_iov = NULL;
125 	}
126 }
127 
128 static void io_netmsg_recycle(struct io_kiocb *req, unsigned int issue_flags)
129 {
130 	struct io_async_msghdr *hdr = req->async_data;
131 	struct iovec *iov;
132 
133 	/* can't recycle, ensure we free the iovec if we have one */
134 	if (unlikely(issue_flags & IO_URING_F_UNLOCKED)) {
135 		io_netmsg_iovec_free(hdr);
136 		return;
137 	}
138 
139 	/* Let normal cleanup path reap it if we fail adding to the cache */
140 	iov = hdr->free_iov;
141 	if (io_alloc_cache_put(&req->ctx->netmsg_cache, hdr)) {
142 		if (iov)
143 			kasan_mempool_poison_object(iov);
144 		req->async_data = NULL;
145 		req->flags &= ~REQ_F_ASYNC_DATA;
146 	}
147 }
148 
149 static struct io_async_msghdr *io_msg_alloc_async(struct io_kiocb *req)
150 {
151 	struct io_ring_ctx *ctx = req->ctx;
152 	struct io_async_msghdr *hdr;
153 
154 	hdr = io_alloc_cache_get(&ctx->netmsg_cache);
155 	if (hdr) {
156 		if (hdr->free_iov) {
157 			kasan_mempool_unpoison_object(hdr->free_iov,
158 				hdr->free_iov_nr * sizeof(struct iovec));
159 			req->flags |= REQ_F_NEED_CLEANUP;
160 		}
161 		req->flags |= REQ_F_ASYNC_DATA;
162 		req->async_data = hdr;
163 		return hdr;
164 	}
165 
166 	if (!io_alloc_async_data(req)) {
167 		hdr = req->async_data;
168 		hdr->free_iov_nr = 0;
169 		hdr->free_iov = NULL;
170 		return hdr;
171 	}
172 	return NULL;
173 }
174 
175 /* assign new iovec to kmsg, if we need to */
176 static int io_net_vec_assign(struct io_kiocb *req, struct io_async_msghdr *kmsg,
177 			     struct iovec *iov)
178 {
179 	if (iov) {
180 		req->flags |= REQ_F_NEED_CLEANUP;
181 		kmsg->free_iov_nr = kmsg->msg.msg_iter.nr_segs;
182 		if (kmsg->free_iov)
183 			kfree(kmsg->free_iov);
184 		kmsg->free_iov = iov;
185 	}
186 	return 0;
187 }
188 
189 static inline void io_mshot_prep_retry(struct io_kiocb *req,
190 				       struct io_async_msghdr *kmsg)
191 {
192 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
193 
194 	req->flags &= ~REQ_F_BL_EMPTY;
195 	sr->done_io = 0;
196 	sr->len = 0; /* get from the provided buffer */
197 	req->buf_index = sr->buf_group;
198 }
199 
200 #ifdef CONFIG_COMPAT
201 static int io_compat_msg_copy_hdr(struct io_kiocb *req,
202 				  struct io_async_msghdr *iomsg,
203 				  struct compat_msghdr *msg, int ddir)
204 {
205 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
206 	struct compat_iovec __user *uiov;
207 	struct iovec *iov;
208 	int ret, nr_segs;
209 
210 	if (iomsg->free_iov) {
211 		nr_segs = iomsg->free_iov_nr;
212 		iov = iomsg->free_iov;
213 	} else {
214 		iov = &iomsg->fast_iov;
215 		nr_segs = 1;
216 	}
217 
218 	if (copy_from_user(msg, sr->umsg_compat, sizeof(*msg)))
219 		return -EFAULT;
220 
221 	uiov = compat_ptr(msg->msg_iov);
222 	if (req->flags & REQ_F_BUFFER_SELECT) {
223 		compat_ssize_t clen;
224 
225 		if (msg->msg_iovlen == 0) {
226 			sr->len = iov->iov_len = 0;
227 			iov->iov_base = NULL;
228 		} else if (msg->msg_iovlen > 1) {
229 			return -EINVAL;
230 		} else {
231 			if (!access_ok(uiov, sizeof(*uiov)))
232 				return -EFAULT;
233 			if (__get_user(clen, &uiov->iov_len))
234 				return -EFAULT;
235 			if (clen < 0)
236 				return -EINVAL;
237 			sr->len = clen;
238 		}
239 
240 		return 0;
241 	}
242 
243 	ret = __import_iovec(ddir, (struct iovec __user *)uiov, msg->msg_iovlen,
244 				nr_segs, &iov, &iomsg->msg.msg_iter, true);
245 	if (unlikely(ret < 0))
246 		return ret;
247 
248 	return io_net_vec_assign(req, iomsg, iov);
249 }
250 #endif
251 
252 static int io_msg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg,
253 			   struct user_msghdr *msg, int ddir)
254 {
255 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
256 	struct iovec *iov;
257 	int ret, nr_segs;
258 
259 	if (iomsg->free_iov) {
260 		nr_segs = iomsg->free_iov_nr;
261 		iov = iomsg->free_iov;
262 	} else {
263 		iov = &iomsg->fast_iov;
264 		nr_segs = 1;
265 	}
266 
267 	if (!user_access_begin(sr->umsg, sizeof(*sr->umsg)))
268 		return -EFAULT;
269 
270 	ret = -EFAULT;
271 	unsafe_get_user(msg->msg_name, &sr->umsg->msg_name, ua_end);
272 	unsafe_get_user(msg->msg_namelen, &sr->umsg->msg_namelen, ua_end);
273 	unsafe_get_user(msg->msg_iov, &sr->umsg->msg_iov, ua_end);
274 	unsafe_get_user(msg->msg_iovlen, &sr->umsg->msg_iovlen, ua_end);
275 	unsafe_get_user(msg->msg_control, &sr->umsg->msg_control, ua_end);
276 	unsafe_get_user(msg->msg_controllen, &sr->umsg->msg_controllen, ua_end);
277 	msg->msg_flags = 0;
278 
279 	if (req->flags & REQ_F_BUFFER_SELECT) {
280 		if (msg->msg_iovlen == 0) {
281 			sr->len = iov->iov_len = 0;
282 			iov->iov_base = NULL;
283 		} else if (msg->msg_iovlen > 1) {
284 			ret = -EINVAL;
285 			goto ua_end;
286 		} else {
287 			/* we only need the length for provided buffers */
288 			if (!access_ok(&msg->msg_iov[0].iov_len, sizeof(__kernel_size_t)))
289 				goto ua_end;
290 			unsafe_get_user(iov->iov_len, &msg->msg_iov[0].iov_len,
291 					ua_end);
292 			sr->len = iov->iov_len;
293 		}
294 		ret = 0;
295 ua_end:
296 		user_access_end();
297 		return ret;
298 	}
299 
300 	user_access_end();
301 	ret = __import_iovec(ddir, msg->msg_iov, msg->msg_iovlen, nr_segs,
302 				&iov, &iomsg->msg.msg_iter, false);
303 	if (unlikely(ret < 0))
304 		return ret;
305 
306 	return io_net_vec_assign(req, iomsg, iov);
307 }
308 
309 static int io_sendmsg_copy_hdr(struct io_kiocb *req,
310 			       struct io_async_msghdr *iomsg)
311 {
312 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
313 	struct user_msghdr msg;
314 	int ret;
315 
316 	iomsg->msg.msg_name = &iomsg->addr;
317 	iomsg->msg.msg_iter.nr_segs = 0;
318 
319 #ifdef CONFIG_COMPAT
320 	if (unlikely(req->ctx->compat)) {
321 		struct compat_msghdr cmsg;
322 
323 		ret = io_compat_msg_copy_hdr(req, iomsg, &cmsg, ITER_SOURCE);
324 		if (unlikely(ret))
325 			return ret;
326 
327 		return __get_compat_msghdr(&iomsg->msg, &cmsg, NULL);
328 	}
329 #endif
330 
331 	ret = io_msg_copy_hdr(req, iomsg, &msg, ITER_SOURCE);
332 	if (unlikely(ret))
333 		return ret;
334 
335 	ret = __copy_msghdr(&iomsg->msg, &msg, NULL);
336 
337 	/* save msg_control as sys_sendmsg() overwrites it */
338 	sr->msg_control = iomsg->msg.msg_control_user;
339 	return ret;
340 }
341 
342 void io_sendmsg_recvmsg_cleanup(struct io_kiocb *req)
343 {
344 	struct io_async_msghdr *io = req->async_data;
345 
346 	io_netmsg_iovec_free(io);
347 }
348 
349 static int io_send_setup(struct io_kiocb *req)
350 {
351 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
352 	struct io_async_msghdr *kmsg = req->async_data;
353 	int ret;
354 
355 	kmsg->msg.msg_name = NULL;
356 	kmsg->msg.msg_namelen = 0;
357 	kmsg->msg.msg_control = NULL;
358 	kmsg->msg.msg_controllen = 0;
359 	kmsg->msg.msg_ubuf = NULL;
360 
361 	if (sr->addr) {
362 		ret = move_addr_to_kernel(sr->addr, sr->addr_len, &kmsg->addr);
363 		if (unlikely(ret < 0))
364 			return ret;
365 		kmsg->msg.msg_name = &kmsg->addr;
366 		kmsg->msg.msg_namelen = sr->addr_len;
367 	}
368 	if (!io_do_buffer_select(req)) {
369 		ret = import_ubuf(ITER_SOURCE, sr->buf, sr->len,
370 				  &kmsg->msg.msg_iter);
371 		if (unlikely(ret < 0))
372 			return ret;
373 	}
374 	return 0;
375 }
376 
377 static int io_sendmsg_prep_setup(struct io_kiocb *req, int is_msg)
378 {
379 	struct io_async_msghdr *kmsg;
380 	int ret;
381 
382 	kmsg = io_msg_alloc_async(req);
383 	if (unlikely(!kmsg))
384 		return -ENOMEM;
385 	if (!is_msg)
386 		return io_send_setup(req);
387 	ret = io_sendmsg_copy_hdr(req, kmsg);
388 	if (!ret)
389 		req->flags |= REQ_F_NEED_CLEANUP;
390 	return ret;
391 }
392 
393 #define SENDMSG_FLAGS (IORING_RECVSEND_POLL_FIRST | IORING_RECVSEND_BUNDLE)
394 
395 int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
396 {
397 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
398 
399 	sr->done_io = 0;
400 
401 	if (req->opcode == IORING_OP_SEND) {
402 		if (READ_ONCE(sqe->__pad3[0]))
403 			return -EINVAL;
404 		sr->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
405 		sr->addr_len = READ_ONCE(sqe->addr_len);
406 	} else if (sqe->addr2 || sqe->file_index) {
407 		return -EINVAL;
408 	}
409 
410 	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
411 	sr->len = READ_ONCE(sqe->len);
412 	sr->flags = READ_ONCE(sqe->ioprio);
413 	if (sr->flags & ~SENDMSG_FLAGS)
414 		return -EINVAL;
415 	sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
416 	if (sr->msg_flags & MSG_DONTWAIT)
417 		req->flags |= REQ_F_NOWAIT;
418 	if (sr->flags & IORING_RECVSEND_BUNDLE) {
419 		if (req->opcode == IORING_OP_SENDMSG)
420 			return -EINVAL;
421 		if (!(req->flags & REQ_F_BUFFER_SELECT))
422 			return -EINVAL;
423 		sr->msg_flags |= MSG_WAITALL;
424 		sr->buf_group = req->buf_index;
425 		req->buf_list = NULL;
426 	}
427 	if (req->flags & REQ_F_BUFFER_SELECT && sr->len)
428 		return -EINVAL;
429 
430 #ifdef CONFIG_COMPAT
431 	if (req->ctx->compat)
432 		sr->msg_flags |= MSG_CMSG_COMPAT;
433 #endif
434 	return io_sendmsg_prep_setup(req, req->opcode == IORING_OP_SENDMSG);
435 }
436 
437 static void io_req_msg_cleanup(struct io_kiocb *req,
438 			       unsigned int issue_flags)
439 {
440 	req->flags &= ~REQ_F_NEED_CLEANUP;
441 	io_netmsg_recycle(req, issue_flags);
442 }
443 
444 /*
445  * For bundle completions, we need to figure out how many segments we consumed.
446  * A bundle could be using a single ITER_UBUF if that's all we mapped, or it
447  * could be using an ITER_IOVEC. If the latter, then if we consumed all of
448  * the segments, then it's a trivial questiont o answer. If we have residual
449  * data in the iter, then loop the segments to figure out how much we
450  * transferred.
451  */
452 static int io_bundle_nbufs(struct io_async_msghdr *kmsg, int ret)
453 {
454 	struct iovec *iov;
455 	int nbufs;
456 
457 	/* no data is always zero segments, and a ubuf is always 1 segment */
458 	if (ret <= 0)
459 		return 0;
460 	if (iter_is_ubuf(&kmsg->msg.msg_iter))
461 		return 1;
462 
463 	iov = kmsg->free_iov;
464 	if (!iov)
465 		iov = &kmsg->fast_iov;
466 
467 	/* if all data was transferred, it's basic pointer math */
468 	if (!iov_iter_count(&kmsg->msg.msg_iter))
469 		return iter_iov(&kmsg->msg.msg_iter) - iov;
470 
471 	/* short transfer, count segments */
472 	nbufs = 0;
473 	do {
474 		int this_len = min_t(int, iov[nbufs].iov_len, ret);
475 
476 		nbufs++;
477 		ret -= this_len;
478 	} while (ret);
479 
480 	return nbufs;
481 }
482 
483 static inline bool io_send_finish(struct io_kiocb *req, int *ret,
484 				  struct io_async_msghdr *kmsg,
485 				  unsigned issue_flags)
486 {
487 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
488 	bool bundle_finished = *ret <= 0;
489 	unsigned int cflags;
490 
491 	if (!(sr->flags & IORING_RECVSEND_BUNDLE)) {
492 		cflags = io_put_kbuf(req, issue_flags);
493 		goto finish;
494 	}
495 
496 	cflags = io_put_kbufs(req, io_bundle_nbufs(kmsg, *ret), issue_flags);
497 
498 	if (bundle_finished || req->flags & REQ_F_BL_EMPTY)
499 		goto finish;
500 
501 	/*
502 	 * Fill CQE for this receive and see if we should keep trying to
503 	 * receive from this socket.
504 	 */
505 	if (io_req_post_cqe(req, *ret, cflags | IORING_CQE_F_MORE)) {
506 		io_mshot_prep_retry(req, kmsg);
507 		return false;
508 	}
509 
510 	/* Otherwise stop bundle and use the current result. */
511 finish:
512 	io_req_set_res(req, *ret, cflags);
513 	*ret = IOU_OK;
514 	return true;
515 }
516 
517 int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
518 {
519 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
520 	struct io_async_msghdr *kmsg = req->async_data;
521 	struct socket *sock;
522 	unsigned flags;
523 	int min_ret = 0;
524 	int ret;
525 
526 	sock = sock_from_file(req->file);
527 	if (unlikely(!sock))
528 		return -ENOTSOCK;
529 
530 	if (!(req->flags & REQ_F_POLLED) &&
531 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
532 		return -EAGAIN;
533 
534 	flags = sr->msg_flags;
535 	if (issue_flags & IO_URING_F_NONBLOCK)
536 		flags |= MSG_DONTWAIT;
537 	if (flags & MSG_WAITALL)
538 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
539 
540 	kmsg->msg.msg_control_user = sr->msg_control;
541 
542 	ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
543 
544 	if (ret < min_ret) {
545 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
546 			return -EAGAIN;
547 		if (ret > 0 && io_net_retry(sock, flags)) {
548 			kmsg->msg.msg_controllen = 0;
549 			kmsg->msg.msg_control = NULL;
550 			sr->done_io += ret;
551 			req->flags |= REQ_F_BL_NO_RECYCLE;
552 			return -EAGAIN;
553 		}
554 		if (ret == -ERESTARTSYS)
555 			ret = -EINTR;
556 		req_set_fail(req);
557 	}
558 	io_req_msg_cleanup(req, issue_flags);
559 	if (ret >= 0)
560 		ret += sr->done_io;
561 	else if (sr->done_io)
562 		ret = sr->done_io;
563 	io_req_set_res(req, ret, 0);
564 	return IOU_OK;
565 }
566 
567 int io_send(struct io_kiocb *req, unsigned int issue_flags)
568 {
569 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
570 	struct io_async_msghdr *kmsg = req->async_data;
571 	struct socket *sock;
572 	unsigned flags;
573 	int min_ret = 0;
574 	int ret;
575 
576 	sock = sock_from_file(req->file);
577 	if (unlikely(!sock))
578 		return -ENOTSOCK;
579 
580 	if (!(req->flags & REQ_F_POLLED) &&
581 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
582 		return -EAGAIN;
583 
584 	flags = sr->msg_flags;
585 	if (issue_flags & IO_URING_F_NONBLOCK)
586 		flags |= MSG_DONTWAIT;
587 
588 retry_bundle:
589 	if (io_do_buffer_select(req)) {
590 		struct buf_sel_arg arg = {
591 			.iovs = &kmsg->fast_iov,
592 			.max_len = INT_MAX,
593 			.nr_iovs = 1,
594 			.mode = KBUF_MODE_EXPAND,
595 		};
596 
597 		if (kmsg->free_iov) {
598 			arg.nr_iovs = kmsg->free_iov_nr;
599 			arg.iovs = kmsg->free_iov;
600 			arg.mode |= KBUF_MODE_FREE;
601 		}
602 
603 		if (!(sr->flags & IORING_RECVSEND_BUNDLE))
604 			arg.nr_iovs = 1;
605 
606 		ret = io_buffers_select(req, &arg, issue_flags);
607 		if (unlikely(ret < 0))
608 			return ret;
609 
610 		sr->len = arg.out_len;
611 		iov_iter_init(&kmsg->msg.msg_iter, ITER_SOURCE, arg.iovs, ret,
612 				arg.out_len);
613 		if (arg.iovs != &kmsg->fast_iov && arg.iovs != kmsg->free_iov) {
614 			kmsg->free_iov_nr = ret;
615 			kmsg->free_iov = arg.iovs;
616 		}
617 	}
618 
619 	/*
620 	 * If MSG_WAITALL is set, or this is a bundle send, then we need
621 	 * the full amount. If just bundle is set, if we do a short send
622 	 * then we complete the bundle sequence rather than continue on.
623 	 */
624 	if (flags & MSG_WAITALL || sr->flags & IORING_RECVSEND_BUNDLE)
625 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
626 
627 	flags &= ~MSG_INTERNAL_SENDMSG_FLAGS;
628 	kmsg->msg.msg_flags = flags;
629 	ret = sock_sendmsg(sock, &kmsg->msg);
630 	if (ret < min_ret) {
631 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
632 			return -EAGAIN;
633 
634 		if (ret > 0 && io_net_retry(sock, flags)) {
635 			sr->len -= ret;
636 			sr->buf += ret;
637 			sr->done_io += ret;
638 			req->flags |= REQ_F_BL_NO_RECYCLE;
639 			return -EAGAIN;
640 		}
641 		if (ret == -ERESTARTSYS)
642 			ret = -EINTR;
643 		req_set_fail(req);
644 	}
645 	if (ret >= 0)
646 		ret += sr->done_io;
647 	else if (sr->done_io)
648 		ret = sr->done_io;
649 
650 	if (!io_send_finish(req, &ret, kmsg, issue_flags))
651 		goto retry_bundle;
652 
653 	io_req_msg_cleanup(req, issue_flags);
654 	return ret;
655 }
656 
657 static int io_recvmsg_mshot_prep(struct io_kiocb *req,
658 				 struct io_async_msghdr *iomsg,
659 				 int namelen, size_t controllen)
660 {
661 	if ((req->flags & (REQ_F_APOLL_MULTISHOT|REQ_F_BUFFER_SELECT)) ==
662 			  (REQ_F_APOLL_MULTISHOT|REQ_F_BUFFER_SELECT)) {
663 		int hdr;
664 
665 		if (unlikely(namelen < 0))
666 			return -EOVERFLOW;
667 		if (check_add_overflow(sizeof(struct io_uring_recvmsg_out),
668 					namelen, &hdr))
669 			return -EOVERFLOW;
670 		if (check_add_overflow(hdr, controllen, &hdr))
671 			return -EOVERFLOW;
672 
673 		iomsg->namelen = namelen;
674 		iomsg->controllen = controllen;
675 		return 0;
676 	}
677 
678 	return 0;
679 }
680 
681 static int io_recvmsg_copy_hdr(struct io_kiocb *req,
682 			       struct io_async_msghdr *iomsg)
683 {
684 	struct user_msghdr msg;
685 	int ret;
686 
687 	iomsg->msg.msg_name = &iomsg->addr;
688 	iomsg->msg.msg_iter.nr_segs = 0;
689 
690 #ifdef CONFIG_COMPAT
691 	if (unlikely(req->ctx->compat)) {
692 		struct compat_msghdr cmsg;
693 
694 		ret = io_compat_msg_copy_hdr(req, iomsg, &cmsg, ITER_DEST);
695 		if (unlikely(ret))
696 			return ret;
697 
698 		ret = __get_compat_msghdr(&iomsg->msg, &cmsg, &iomsg->uaddr);
699 		if (unlikely(ret))
700 			return ret;
701 
702 		return io_recvmsg_mshot_prep(req, iomsg, cmsg.msg_namelen,
703 						cmsg.msg_controllen);
704 	}
705 #endif
706 
707 	ret = io_msg_copy_hdr(req, iomsg, &msg, ITER_DEST);
708 	if (unlikely(ret))
709 		return ret;
710 
711 	ret = __copy_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
712 	if (unlikely(ret))
713 		return ret;
714 
715 	return io_recvmsg_mshot_prep(req, iomsg, msg.msg_namelen,
716 					msg.msg_controllen);
717 }
718 
719 static int io_recvmsg_prep_setup(struct io_kiocb *req)
720 {
721 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
722 	struct io_async_msghdr *kmsg;
723 	int ret;
724 
725 	kmsg = io_msg_alloc_async(req);
726 	if (unlikely(!kmsg))
727 		return -ENOMEM;
728 
729 	if (req->opcode == IORING_OP_RECV) {
730 		kmsg->msg.msg_name = NULL;
731 		kmsg->msg.msg_namelen = 0;
732 		kmsg->msg.msg_control = NULL;
733 		kmsg->msg.msg_get_inq = 1;
734 		kmsg->msg.msg_controllen = 0;
735 		kmsg->msg.msg_iocb = NULL;
736 		kmsg->msg.msg_ubuf = NULL;
737 
738 		if (!io_do_buffer_select(req)) {
739 			ret = import_ubuf(ITER_DEST, sr->buf, sr->len,
740 					  &kmsg->msg.msg_iter);
741 			if (unlikely(ret))
742 				return ret;
743 		}
744 		return 0;
745 	}
746 
747 	ret = io_recvmsg_copy_hdr(req, kmsg);
748 	if (!ret)
749 		req->flags |= REQ_F_NEED_CLEANUP;
750 	return ret;
751 }
752 
753 #define RECVMSG_FLAGS (IORING_RECVSEND_POLL_FIRST | IORING_RECV_MULTISHOT | \
754 			IORING_RECVSEND_BUNDLE)
755 
756 int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
757 {
758 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
759 
760 	sr->done_io = 0;
761 
762 	if (unlikely(sqe->file_index || sqe->addr2))
763 		return -EINVAL;
764 
765 	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
766 	sr->len = READ_ONCE(sqe->len);
767 	sr->flags = READ_ONCE(sqe->ioprio);
768 	if (sr->flags & ~RECVMSG_FLAGS)
769 		return -EINVAL;
770 	sr->msg_flags = READ_ONCE(sqe->msg_flags);
771 	if (sr->msg_flags & MSG_DONTWAIT)
772 		req->flags |= REQ_F_NOWAIT;
773 	if (sr->msg_flags & MSG_ERRQUEUE)
774 		req->flags |= REQ_F_CLEAR_POLLIN;
775 	if (req->flags & REQ_F_BUFFER_SELECT) {
776 		/*
777 		 * Store the buffer group for this multishot receive separately,
778 		 * as if we end up doing an io-wq based issue that selects a
779 		 * buffer, it has to be committed immediately and that will
780 		 * clear ->buf_list. This means we lose the link to the buffer
781 		 * list, and the eventual buffer put on completion then cannot
782 		 * restore it.
783 		 */
784 		sr->buf_group = req->buf_index;
785 		req->buf_list = NULL;
786 	}
787 	if (sr->flags & IORING_RECV_MULTISHOT) {
788 		if (!(req->flags & REQ_F_BUFFER_SELECT))
789 			return -EINVAL;
790 		if (sr->msg_flags & MSG_WAITALL)
791 			return -EINVAL;
792 		if (req->opcode == IORING_OP_RECV && sr->len)
793 			return -EINVAL;
794 		req->flags |= REQ_F_APOLL_MULTISHOT;
795 	}
796 	if (sr->flags & IORING_RECVSEND_BUNDLE) {
797 		if (req->opcode == IORING_OP_RECVMSG)
798 			return -EINVAL;
799 	}
800 
801 #ifdef CONFIG_COMPAT
802 	if (req->ctx->compat)
803 		sr->msg_flags |= MSG_CMSG_COMPAT;
804 #endif
805 	sr->nr_multishot_loops = 0;
806 	return io_recvmsg_prep_setup(req);
807 }
808 
809 /*
810  * Finishes io_recv and io_recvmsg.
811  *
812  * Returns true if it is actually finished, or false if it should run
813  * again (for multishot).
814  */
815 static inline bool io_recv_finish(struct io_kiocb *req, int *ret,
816 				  struct io_async_msghdr *kmsg,
817 				  bool mshot_finished, unsigned issue_flags)
818 {
819 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
820 	unsigned int cflags;
821 
822 	if (sr->flags & IORING_RECVSEND_BUNDLE)
823 		cflags = io_put_kbufs(req, io_bundle_nbufs(kmsg, *ret),
824 				      issue_flags);
825 	else
826 		cflags = io_put_kbuf(req, issue_flags);
827 
828 	if (kmsg->msg.msg_inq > 0)
829 		cflags |= IORING_CQE_F_SOCK_NONEMPTY;
830 
831 	/* bundle with no more immediate buffers, we're done */
832 	if (sr->flags & IORING_RECVSEND_BUNDLE && req->flags & REQ_F_BL_EMPTY)
833 		goto finish;
834 
835 	/*
836 	 * Fill CQE for this receive and see if we should keep trying to
837 	 * receive from this socket.
838 	 */
839 	if ((req->flags & REQ_F_APOLL_MULTISHOT) && !mshot_finished &&
840 	    io_req_post_cqe(req, *ret, cflags | IORING_CQE_F_MORE)) {
841 		int mshot_retry_ret = IOU_ISSUE_SKIP_COMPLETE;
842 
843 		io_mshot_prep_retry(req, kmsg);
844 		/* Known not-empty or unknown state, retry */
845 		if (cflags & IORING_CQE_F_SOCK_NONEMPTY || kmsg->msg.msg_inq < 0) {
846 			if (sr->nr_multishot_loops++ < MULTISHOT_MAX_RETRY)
847 				return false;
848 			/* mshot retries exceeded, force a requeue */
849 			sr->nr_multishot_loops = 0;
850 			mshot_retry_ret = IOU_REQUEUE;
851 		}
852 		if (issue_flags & IO_URING_F_MULTISHOT)
853 			*ret = mshot_retry_ret;
854 		else
855 			*ret = -EAGAIN;
856 		return true;
857 	}
858 
859 	/* Finish the request / stop multishot. */
860 finish:
861 	io_req_set_res(req, *ret, cflags);
862 
863 	if (issue_flags & IO_URING_F_MULTISHOT)
864 		*ret = IOU_STOP_MULTISHOT;
865 	else
866 		*ret = IOU_OK;
867 	io_req_msg_cleanup(req, issue_flags);
868 	return true;
869 }
870 
871 static int io_recvmsg_prep_multishot(struct io_async_msghdr *kmsg,
872 				     struct io_sr_msg *sr, void __user **buf,
873 				     size_t *len)
874 {
875 	unsigned long ubuf = (unsigned long) *buf;
876 	unsigned long hdr;
877 
878 	hdr = sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
879 		kmsg->controllen;
880 	if (*len < hdr)
881 		return -EFAULT;
882 
883 	if (kmsg->controllen) {
884 		unsigned long control = ubuf + hdr - kmsg->controllen;
885 
886 		kmsg->msg.msg_control_user = (void __user *) control;
887 		kmsg->msg.msg_controllen = kmsg->controllen;
888 	}
889 
890 	sr->buf = *buf; /* stash for later copy */
891 	*buf = (void __user *) (ubuf + hdr);
892 	kmsg->payloadlen = *len = *len - hdr;
893 	return 0;
894 }
895 
896 struct io_recvmsg_multishot_hdr {
897 	struct io_uring_recvmsg_out msg;
898 	struct sockaddr_storage addr;
899 };
900 
901 static int io_recvmsg_multishot(struct socket *sock, struct io_sr_msg *io,
902 				struct io_async_msghdr *kmsg,
903 				unsigned int flags, bool *finished)
904 {
905 	int err;
906 	int copy_len;
907 	struct io_recvmsg_multishot_hdr hdr;
908 
909 	if (kmsg->namelen)
910 		kmsg->msg.msg_name = &hdr.addr;
911 	kmsg->msg.msg_flags = flags & (MSG_CMSG_CLOEXEC|MSG_CMSG_COMPAT);
912 	kmsg->msg.msg_namelen = 0;
913 
914 	if (sock->file->f_flags & O_NONBLOCK)
915 		flags |= MSG_DONTWAIT;
916 
917 	err = sock_recvmsg(sock, &kmsg->msg, flags);
918 	*finished = err <= 0;
919 	if (err < 0)
920 		return err;
921 
922 	hdr.msg = (struct io_uring_recvmsg_out) {
923 		.controllen = kmsg->controllen - kmsg->msg.msg_controllen,
924 		.flags = kmsg->msg.msg_flags & ~MSG_CMSG_COMPAT
925 	};
926 
927 	hdr.msg.payloadlen = err;
928 	if (err > kmsg->payloadlen)
929 		err = kmsg->payloadlen;
930 
931 	copy_len = sizeof(struct io_uring_recvmsg_out);
932 	if (kmsg->msg.msg_namelen > kmsg->namelen)
933 		copy_len += kmsg->namelen;
934 	else
935 		copy_len += kmsg->msg.msg_namelen;
936 
937 	/*
938 	 *      "fromlen shall refer to the value before truncation.."
939 	 *                      1003.1g
940 	 */
941 	hdr.msg.namelen = kmsg->msg.msg_namelen;
942 
943 	/* ensure that there is no gap between hdr and sockaddr_storage */
944 	BUILD_BUG_ON(offsetof(struct io_recvmsg_multishot_hdr, addr) !=
945 		     sizeof(struct io_uring_recvmsg_out));
946 	if (copy_to_user(io->buf, &hdr, copy_len)) {
947 		*finished = true;
948 		return -EFAULT;
949 	}
950 
951 	return sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
952 			kmsg->controllen + err;
953 }
954 
955 int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
956 {
957 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
958 	struct io_async_msghdr *kmsg = req->async_data;
959 	struct socket *sock;
960 	unsigned flags;
961 	int ret, min_ret = 0;
962 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
963 	bool mshot_finished = true;
964 
965 	sock = sock_from_file(req->file);
966 	if (unlikely(!sock))
967 		return -ENOTSOCK;
968 
969 	if (!(req->flags & REQ_F_POLLED) &&
970 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
971 		return -EAGAIN;
972 
973 	flags = sr->msg_flags;
974 	if (force_nonblock)
975 		flags |= MSG_DONTWAIT;
976 
977 retry_multishot:
978 	if (io_do_buffer_select(req)) {
979 		void __user *buf;
980 		size_t len = sr->len;
981 
982 		buf = io_buffer_select(req, &len, issue_flags);
983 		if (!buf)
984 			return -ENOBUFS;
985 
986 		if (req->flags & REQ_F_APOLL_MULTISHOT) {
987 			ret = io_recvmsg_prep_multishot(kmsg, sr, &buf, &len);
988 			if (ret) {
989 				io_kbuf_recycle(req, issue_flags);
990 				return ret;
991 			}
992 		}
993 
994 		iov_iter_ubuf(&kmsg->msg.msg_iter, ITER_DEST, buf, len);
995 	}
996 
997 	kmsg->msg.msg_get_inq = 1;
998 	kmsg->msg.msg_inq = -1;
999 	if (req->flags & REQ_F_APOLL_MULTISHOT) {
1000 		ret = io_recvmsg_multishot(sock, sr, kmsg, flags,
1001 					   &mshot_finished);
1002 	} else {
1003 		/* disable partial retry for recvmsg with cmsg attached */
1004 		if (flags & MSG_WAITALL && !kmsg->msg.msg_controllen)
1005 			min_ret = iov_iter_count(&kmsg->msg.msg_iter);
1006 
1007 		ret = __sys_recvmsg_sock(sock, &kmsg->msg, sr->umsg,
1008 					 kmsg->uaddr, flags);
1009 	}
1010 
1011 	if (ret < min_ret) {
1012 		if (ret == -EAGAIN && force_nonblock) {
1013 			if (issue_flags & IO_URING_F_MULTISHOT) {
1014 				io_kbuf_recycle(req, issue_flags);
1015 				return IOU_ISSUE_SKIP_COMPLETE;
1016 			}
1017 			return -EAGAIN;
1018 		}
1019 		if (ret > 0 && io_net_retry(sock, flags)) {
1020 			sr->done_io += ret;
1021 			req->flags |= REQ_F_BL_NO_RECYCLE;
1022 			return -EAGAIN;
1023 		}
1024 		if (ret == -ERESTARTSYS)
1025 			ret = -EINTR;
1026 		req_set_fail(req);
1027 	} else if ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
1028 		req_set_fail(req);
1029 	}
1030 
1031 	if (ret > 0)
1032 		ret += sr->done_io;
1033 	else if (sr->done_io)
1034 		ret = sr->done_io;
1035 	else
1036 		io_kbuf_recycle(req, issue_flags);
1037 
1038 	if (!io_recv_finish(req, &ret, kmsg, mshot_finished, issue_flags))
1039 		goto retry_multishot;
1040 
1041 	return ret;
1042 }
1043 
1044 static int io_recv_buf_select(struct io_kiocb *req, struct io_async_msghdr *kmsg,
1045 			      size_t *len, unsigned int issue_flags)
1046 {
1047 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
1048 	int ret;
1049 
1050 	/*
1051 	 * If the ring isn't locked, then don't use the peek interface
1052 	 * to grab multiple buffers as we will lock/unlock between
1053 	 * this selection and posting the buffers.
1054 	 */
1055 	if (!(issue_flags & IO_URING_F_UNLOCKED) &&
1056 	    sr->flags & IORING_RECVSEND_BUNDLE) {
1057 		struct buf_sel_arg arg = {
1058 			.iovs = &kmsg->fast_iov,
1059 			.nr_iovs = 1,
1060 			.mode = KBUF_MODE_EXPAND,
1061 		};
1062 
1063 		if (kmsg->free_iov) {
1064 			arg.nr_iovs = kmsg->free_iov_nr;
1065 			arg.iovs = kmsg->free_iov;
1066 			arg.mode |= KBUF_MODE_FREE;
1067 		}
1068 
1069 		if (kmsg->msg.msg_inq > 0)
1070 			arg.max_len = min_not_zero(sr->len, kmsg->msg.msg_inq);
1071 
1072 		ret = io_buffers_peek(req, &arg);
1073 		if (unlikely(ret < 0))
1074 			return ret;
1075 
1076 		/* special case 1 vec, can be a fast path */
1077 		if (ret == 1) {
1078 			sr->buf = arg.iovs[0].iov_base;
1079 			sr->len = arg.iovs[0].iov_len;
1080 			goto map_ubuf;
1081 		}
1082 		iov_iter_init(&kmsg->msg.msg_iter, ITER_DEST, arg.iovs, ret,
1083 				arg.out_len);
1084 		if (arg.iovs != &kmsg->fast_iov && arg.iovs != kmsg->free_iov) {
1085 			kmsg->free_iov_nr = ret;
1086 			kmsg->free_iov = arg.iovs;
1087 		}
1088 	} else {
1089 		void __user *buf;
1090 
1091 		*len = sr->len;
1092 		buf = io_buffer_select(req, len, issue_flags);
1093 		if (!buf)
1094 			return -ENOBUFS;
1095 		sr->buf = buf;
1096 		sr->len = *len;
1097 map_ubuf:
1098 		ret = import_ubuf(ITER_DEST, sr->buf, sr->len,
1099 				  &kmsg->msg.msg_iter);
1100 		if (unlikely(ret))
1101 			return ret;
1102 	}
1103 
1104 	return 0;
1105 }
1106 
1107 int io_recv(struct io_kiocb *req, unsigned int issue_flags)
1108 {
1109 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
1110 	struct io_async_msghdr *kmsg = req->async_data;
1111 	struct socket *sock;
1112 	unsigned flags;
1113 	int ret, min_ret = 0;
1114 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
1115 	size_t len = sr->len;
1116 
1117 	if (!(req->flags & REQ_F_POLLED) &&
1118 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
1119 		return -EAGAIN;
1120 
1121 	sock = sock_from_file(req->file);
1122 	if (unlikely(!sock))
1123 		return -ENOTSOCK;
1124 
1125 	flags = sr->msg_flags;
1126 	if (force_nonblock)
1127 		flags |= MSG_DONTWAIT;
1128 
1129 retry_multishot:
1130 	if (io_do_buffer_select(req)) {
1131 		ret = io_recv_buf_select(req, kmsg, &len, issue_flags);
1132 		if (unlikely(ret)) {
1133 			kmsg->msg.msg_inq = -1;
1134 			goto out_free;
1135 		}
1136 		sr->buf = NULL;
1137 	}
1138 
1139 	kmsg->msg.msg_flags = 0;
1140 	kmsg->msg.msg_inq = -1;
1141 
1142 	if (flags & MSG_WAITALL)
1143 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
1144 
1145 	ret = sock_recvmsg(sock, &kmsg->msg, flags);
1146 	if (ret < min_ret) {
1147 		if (ret == -EAGAIN && force_nonblock) {
1148 			if (issue_flags & IO_URING_F_MULTISHOT) {
1149 				io_kbuf_recycle(req, issue_flags);
1150 				return IOU_ISSUE_SKIP_COMPLETE;
1151 			}
1152 
1153 			return -EAGAIN;
1154 		}
1155 		if (ret > 0 && io_net_retry(sock, flags)) {
1156 			sr->len -= ret;
1157 			sr->buf += ret;
1158 			sr->done_io += ret;
1159 			req->flags |= REQ_F_BL_NO_RECYCLE;
1160 			return -EAGAIN;
1161 		}
1162 		if (ret == -ERESTARTSYS)
1163 			ret = -EINTR;
1164 		req_set_fail(req);
1165 	} else if ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
1166 out_free:
1167 		req_set_fail(req);
1168 	}
1169 
1170 	if (ret > 0)
1171 		ret += sr->done_io;
1172 	else if (sr->done_io)
1173 		ret = sr->done_io;
1174 	else
1175 		io_kbuf_recycle(req, issue_flags);
1176 
1177 	if (!io_recv_finish(req, &ret, kmsg, ret <= 0, issue_flags))
1178 		goto retry_multishot;
1179 
1180 	return ret;
1181 }
1182 
1183 void io_send_zc_cleanup(struct io_kiocb *req)
1184 {
1185 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
1186 	struct io_async_msghdr *io = req->async_data;
1187 
1188 	if (req_has_async_data(req))
1189 		io_netmsg_iovec_free(io);
1190 	if (zc->notif) {
1191 		io_notif_flush(zc->notif);
1192 		zc->notif = NULL;
1193 	}
1194 }
1195 
1196 #define IO_ZC_FLAGS_COMMON (IORING_RECVSEND_POLL_FIRST | IORING_RECVSEND_FIXED_BUF)
1197 #define IO_ZC_FLAGS_VALID  (IO_ZC_FLAGS_COMMON | IORING_SEND_ZC_REPORT_USAGE)
1198 
1199 int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1200 {
1201 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
1202 	struct io_ring_ctx *ctx = req->ctx;
1203 	struct io_kiocb *notif;
1204 
1205 	zc->done_io = 0;
1206 	req->flags |= REQ_F_POLL_NO_LAZY;
1207 
1208 	if (unlikely(READ_ONCE(sqe->__pad2[0]) || READ_ONCE(sqe->addr3)))
1209 		return -EINVAL;
1210 	/* we don't support IOSQE_CQE_SKIP_SUCCESS just yet */
1211 	if (req->flags & REQ_F_CQE_SKIP)
1212 		return -EINVAL;
1213 
1214 	notif = zc->notif = io_alloc_notif(ctx);
1215 	if (!notif)
1216 		return -ENOMEM;
1217 	notif->cqe.user_data = req->cqe.user_data;
1218 	notif->cqe.res = 0;
1219 	notif->cqe.flags = IORING_CQE_F_NOTIF;
1220 	req->flags |= REQ_F_NEED_CLEANUP;
1221 
1222 	zc->flags = READ_ONCE(sqe->ioprio);
1223 	if (unlikely(zc->flags & ~IO_ZC_FLAGS_COMMON)) {
1224 		if (zc->flags & ~IO_ZC_FLAGS_VALID)
1225 			return -EINVAL;
1226 		if (zc->flags & IORING_SEND_ZC_REPORT_USAGE) {
1227 			struct io_notif_data *nd = io_notif_to_data(notif);
1228 
1229 			nd->zc_report = true;
1230 			nd->zc_used = false;
1231 			nd->zc_copied = false;
1232 		}
1233 	}
1234 
1235 	if (zc->flags & IORING_RECVSEND_FIXED_BUF) {
1236 		unsigned idx = READ_ONCE(sqe->buf_index);
1237 
1238 		if (unlikely(idx >= ctx->nr_user_bufs))
1239 			return -EFAULT;
1240 		idx = array_index_nospec(idx, ctx->nr_user_bufs);
1241 		req->imu = READ_ONCE(ctx->user_bufs[idx]);
1242 		io_req_set_rsrc_node(notif, ctx, 0);
1243 	}
1244 
1245 	if (req->opcode == IORING_OP_SEND_ZC) {
1246 		if (READ_ONCE(sqe->__pad3[0]))
1247 			return -EINVAL;
1248 		zc->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
1249 		zc->addr_len = READ_ONCE(sqe->addr_len);
1250 	} else {
1251 		if (unlikely(sqe->addr2 || sqe->file_index))
1252 			return -EINVAL;
1253 		if (unlikely(zc->flags & IORING_RECVSEND_FIXED_BUF))
1254 			return -EINVAL;
1255 	}
1256 
1257 	zc->buf = u64_to_user_ptr(READ_ONCE(sqe->addr));
1258 	zc->len = READ_ONCE(sqe->len);
1259 	zc->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL | MSG_ZEROCOPY;
1260 	if (zc->msg_flags & MSG_DONTWAIT)
1261 		req->flags |= REQ_F_NOWAIT;
1262 
1263 #ifdef CONFIG_COMPAT
1264 	if (req->ctx->compat)
1265 		zc->msg_flags |= MSG_CMSG_COMPAT;
1266 #endif
1267 	return io_sendmsg_prep_setup(req, req->opcode == IORING_OP_SENDMSG_ZC);
1268 }
1269 
1270 static int io_sg_from_iter_iovec(struct sock *sk, struct sk_buff *skb,
1271 				 struct iov_iter *from, size_t length)
1272 {
1273 	skb_zcopy_downgrade_managed(skb);
1274 	return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
1275 }
1276 
1277 static int io_sg_from_iter(struct sock *sk, struct sk_buff *skb,
1278 			   struct iov_iter *from, size_t length)
1279 {
1280 	struct skb_shared_info *shinfo = skb_shinfo(skb);
1281 	int frag = shinfo->nr_frags;
1282 	int ret = 0;
1283 	struct bvec_iter bi;
1284 	ssize_t copied = 0;
1285 	unsigned long truesize = 0;
1286 
1287 	if (!frag)
1288 		shinfo->flags |= SKBFL_MANAGED_FRAG_REFS;
1289 	else if (unlikely(!skb_zcopy_managed(skb)))
1290 		return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
1291 
1292 	bi.bi_size = min(from->count, length);
1293 	bi.bi_bvec_done = from->iov_offset;
1294 	bi.bi_idx = 0;
1295 
1296 	while (bi.bi_size && frag < MAX_SKB_FRAGS) {
1297 		struct bio_vec v = mp_bvec_iter_bvec(from->bvec, bi);
1298 
1299 		copied += v.bv_len;
1300 		truesize += PAGE_ALIGN(v.bv_len + v.bv_offset);
1301 		__skb_fill_page_desc_noacc(shinfo, frag++, v.bv_page,
1302 					   v.bv_offset, v.bv_len);
1303 		bvec_iter_advance_single(from->bvec, &bi, v.bv_len);
1304 	}
1305 	if (bi.bi_size)
1306 		ret = -EMSGSIZE;
1307 
1308 	shinfo->nr_frags = frag;
1309 	from->bvec += bi.bi_idx;
1310 	from->nr_segs -= bi.bi_idx;
1311 	from->count -= copied;
1312 	from->iov_offset = bi.bi_bvec_done;
1313 
1314 	skb->data_len += copied;
1315 	skb->len += copied;
1316 	skb->truesize += truesize;
1317 
1318 	if (sk && sk->sk_type == SOCK_STREAM) {
1319 		sk_wmem_queued_add(sk, truesize);
1320 		if (!skb_zcopy_pure(skb))
1321 			sk_mem_charge(sk, truesize);
1322 	} else {
1323 		refcount_add(truesize, &skb->sk->sk_wmem_alloc);
1324 	}
1325 	return ret;
1326 }
1327 
1328 static int io_send_zc_import(struct io_kiocb *req, struct io_async_msghdr *kmsg)
1329 {
1330 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
1331 	int ret;
1332 
1333 	if (sr->flags & IORING_RECVSEND_FIXED_BUF) {
1334 		ret = io_import_fixed(ITER_SOURCE, &kmsg->msg.msg_iter, req->imu,
1335 					(u64)(uintptr_t)sr->buf, sr->len);
1336 		if (unlikely(ret))
1337 			return ret;
1338 		kmsg->msg.sg_from_iter = io_sg_from_iter;
1339 	} else {
1340 		ret = import_ubuf(ITER_SOURCE, sr->buf, sr->len, &kmsg->msg.msg_iter);
1341 		if (unlikely(ret))
1342 			return ret;
1343 		ret = io_notif_account_mem(sr->notif, sr->len);
1344 		if (unlikely(ret))
1345 			return ret;
1346 		kmsg->msg.sg_from_iter = io_sg_from_iter_iovec;
1347 	}
1348 
1349 	return ret;
1350 }
1351 
1352 int io_send_zc(struct io_kiocb *req, unsigned int issue_flags)
1353 {
1354 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
1355 	struct io_async_msghdr *kmsg = req->async_data;
1356 	struct socket *sock;
1357 	unsigned msg_flags;
1358 	int ret, min_ret = 0;
1359 
1360 	sock = sock_from_file(req->file);
1361 	if (unlikely(!sock))
1362 		return -ENOTSOCK;
1363 	if (!test_bit(SOCK_SUPPORT_ZC, &sock->flags))
1364 		return -EOPNOTSUPP;
1365 
1366 	if (!(req->flags & REQ_F_POLLED) &&
1367 	    (zc->flags & IORING_RECVSEND_POLL_FIRST))
1368 		return -EAGAIN;
1369 
1370 	if (!zc->done_io) {
1371 		ret = io_send_zc_import(req, kmsg);
1372 		if (unlikely(ret))
1373 			return ret;
1374 	}
1375 
1376 	msg_flags = zc->msg_flags;
1377 	if (issue_flags & IO_URING_F_NONBLOCK)
1378 		msg_flags |= MSG_DONTWAIT;
1379 	if (msg_flags & MSG_WAITALL)
1380 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
1381 	msg_flags &= ~MSG_INTERNAL_SENDMSG_FLAGS;
1382 
1383 	kmsg->msg.msg_flags = msg_flags;
1384 	kmsg->msg.msg_ubuf = &io_notif_to_data(zc->notif)->uarg;
1385 	ret = sock_sendmsg(sock, &kmsg->msg);
1386 
1387 	if (unlikely(ret < min_ret)) {
1388 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1389 			return -EAGAIN;
1390 
1391 		if (ret > 0 && io_net_retry(sock, kmsg->msg.msg_flags)) {
1392 			zc->len -= ret;
1393 			zc->buf += ret;
1394 			zc->done_io += ret;
1395 			req->flags |= REQ_F_BL_NO_RECYCLE;
1396 			return -EAGAIN;
1397 		}
1398 		if (ret == -ERESTARTSYS)
1399 			ret = -EINTR;
1400 		req_set_fail(req);
1401 	}
1402 
1403 	if (ret >= 0)
1404 		ret += zc->done_io;
1405 	else if (zc->done_io)
1406 		ret = zc->done_io;
1407 
1408 	/*
1409 	 * If we're in io-wq we can't rely on tw ordering guarantees, defer
1410 	 * flushing notif to io_send_zc_cleanup()
1411 	 */
1412 	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
1413 		io_notif_flush(zc->notif);
1414 		io_req_msg_cleanup(req, 0);
1415 	}
1416 	io_req_set_res(req, ret, IORING_CQE_F_MORE);
1417 	return IOU_OK;
1418 }
1419 
1420 int io_sendmsg_zc(struct io_kiocb *req, unsigned int issue_flags)
1421 {
1422 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
1423 	struct io_async_msghdr *kmsg = req->async_data;
1424 	struct socket *sock;
1425 	unsigned flags;
1426 	int ret, min_ret = 0;
1427 
1428 	sock = sock_from_file(req->file);
1429 	if (unlikely(!sock))
1430 		return -ENOTSOCK;
1431 	if (!test_bit(SOCK_SUPPORT_ZC, &sock->flags))
1432 		return -EOPNOTSUPP;
1433 
1434 	if (!(req->flags & REQ_F_POLLED) &&
1435 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
1436 		return -EAGAIN;
1437 
1438 	flags = sr->msg_flags;
1439 	if (issue_flags & IO_URING_F_NONBLOCK)
1440 		flags |= MSG_DONTWAIT;
1441 	if (flags & MSG_WAITALL)
1442 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
1443 
1444 	kmsg->msg.msg_control_user = sr->msg_control;
1445 	kmsg->msg.msg_ubuf = &io_notif_to_data(sr->notif)->uarg;
1446 	kmsg->msg.sg_from_iter = io_sg_from_iter_iovec;
1447 	ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
1448 
1449 	if (unlikely(ret < min_ret)) {
1450 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1451 			return -EAGAIN;
1452 
1453 		if (ret > 0 && io_net_retry(sock, flags)) {
1454 			sr->done_io += ret;
1455 			req->flags |= REQ_F_BL_NO_RECYCLE;
1456 			return -EAGAIN;
1457 		}
1458 		if (ret == -ERESTARTSYS)
1459 			ret = -EINTR;
1460 		req_set_fail(req);
1461 	}
1462 
1463 	if (ret >= 0)
1464 		ret += sr->done_io;
1465 	else if (sr->done_io)
1466 		ret = sr->done_io;
1467 
1468 	/*
1469 	 * If we're in io-wq we can't rely on tw ordering guarantees, defer
1470 	 * flushing notif to io_send_zc_cleanup()
1471 	 */
1472 	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
1473 		io_notif_flush(sr->notif);
1474 		io_req_msg_cleanup(req, 0);
1475 	}
1476 	io_req_set_res(req, ret, IORING_CQE_F_MORE);
1477 	return IOU_OK;
1478 }
1479 
1480 void io_sendrecv_fail(struct io_kiocb *req)
1481 {
1482 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
1483 
1484 	if (sr->done_io)
1485 		req->cqe.res = sr->done_io;
1486 
1487 	if ((req->flags & REQ_F_NEED_CLEANUP) &&
1488 	    (req->opcode == IORING_OP_SEND_ZC || req->opcode == IORING_OP_SENDMSG_ZC))
1489 		req->cqe.flags |= IORING_CQE_F_MORE;
1490 }
1491 
1492 #define ACCEPT_FLAGS	(IORING_ACCEPT_MULTISHOT | IORING_ACCEPT_DONTWAIT | \
1493 			 IORING_ACCEPT_POLL_FIRST)
1494 
1495 int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1496 {
1497 	struct io_accept *accept = io_kiocb_to_cmd(req, struct io_accept);
1498 
1499 	if (sqe->len || sqe->buf_index)
1500 		return -EINVAL;
1501 
1502 	accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
1503 	accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2));
1504 	accept->flags = READ_ONCE(sqe->accept_flags);
1505 	accept->nofile = rlimit(RLIMIT_NOFILE);
1506 	accept->iou_flags = READ_ONCE(sqe->ioprio);
1507 	if (accept->iou_flags & ~ACCEPT_FLAGS)
1508 		return -EINVAL;
1509 
1510 	accept->file_slot = READ_ONCE(sqe->file_index);
1511 	if (accept->file_slot) {
1512 		if (accept->flags & SOCK_CLOEXEC)
1513 			return -EINVAL;
1514 		if (accept->iou_flags & IORING_ACCEPT_MULTISHOT &&
1515 		    accept->file_slot != IORING_FILE_INDEX_ALLOC)
1516 			return -EINVAL;
1517 	}
1518 	if (accept->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
1519 		return -EINVAL;
1520 	if (SOCK_NONBLOCK != O_NONBLOCK && (accept->flags & SOCK_NONBLOCK))
1521 		accept->flags = (accept->flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
1522 	if (accept->iou_flags & IORING_ACCEPT_MULTISHOT)
1523 		req->flags |= REQ_F_APOLL_MULTISHOT;
1524 	if (accept->iou_flags & IORING_ACCEPT_DONTWAIT)
1525 		req->flags |= REQ_F_NOWAIT;
1526 	return 0;
1527 }
1528 
1529 int io_accept(struct io_kiocb *req, unsigned int issue_flags)
1530 {
1531 	struct io_accept *accept = io_kiocb_to_cmd(req, struct io_accept);
1532 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
1533 	bool fixed = !!accept->file_slot;
1534 	struct proto_accept_arg arg = {
1535 		.flags = force_nonblock ? O_NONBLOCK : 0,
1536 	};
1537 	struct file *file;
1538 	unsigned cflags;
1539 	int ret, fd;
1540 
1541 	if (!(req->flags & REQ_F_POLLED) &&
1542 	    accept->iou_flags & IORING_ACCEPT_POLL_FIRST)
1543 		return -EAGAIN;
1544 
1545 retry:
1546 	if (!fixed) {
1547 		fd = __get_unused_fd_flags(accept->flags, accept->nofile);
1548 		if (unlikely(fd < 0))
1549 			return fd;
1550 	}
1551 	arg.err = 0;
1552 	arg.is_empty = -1;
1553 	file = do_accept(req->file, &arg, accept->addr, accept->addr_len,
1554 			 accept->flags);
1555 	if (IS_ERR(file)) {
1556 		if (!fixed)
1557 			put_unused_fd(fd);
1558 		ret = PTR_ERR(file);
1559 		if (ret == -EAGAIN && force_nonblock &&
1560 		    !(accept->iou_flags & IORING_ACCEPT_DONTWAIT)) {
1561 			/*
1562 			 * if it's multishot and polled, we don't need to
1563 			 * return EAGAIN to arm the poll infra since it
1564 			 * has already been done
1565 			 */
1566 			if (issue_flags & IO_URING_F_MULTISHOT)
1567 				return IOU_ISSUE_SKIP_COMPLETE;
1568 			return ret;
1569 		}
1570 		if (ret == -ERESTARTSYS)
1571 			ret = -EINTR;
1572 		req_set_fail(req);
1573 	} else if (!fixed) {
1574 		fd_install(fd, file);
1575 		ret = fd;
1576 	} else {
1577 		ret = io_fixed_fd_install(req, issue_flags, file,
1578 						accept->file_slot);
1579 	}
1580 
1581 	cflags = 0;
1582 	if (!arg.is_empty)
1583 		cflags |= IORING_CQE_F_SOCK_NONEMPTY;
1584 
1585 	if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
1586 		io_req_set_res(req, ret, cflags);
1587 		return IOU_OK;
1588 	}
1589 
1590 	if (ret < 0)
1591 		return ret;
1592 	if (io_req_post_cqe(req, ret, cflags | IORING_CQE_F_MORE)) {
1593 		if (cflags & IORING_CQE_F_SOCK_NONEMPTY || arg.is_empty == -1)
1594 			goto retry;
1595 		if (issue_flags & IO_URING_F_MULTISHOT)
1596 			return IOU_ISSUE_SKIP_COMPLETE;
1597 		return -EAGAIN;
1598 	}
1599 
1600 	io_req_set_res(req, ret, cflags);
1601 	return IOU_STOP_MULTISHOT;
1602 }
1603 
1604 int io_socket_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1605 {
1606 	struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
1607 
1608 	if (sqe->addr || sqe->rw_flags || sqe->buf_index)
1609 		return -EINVAL;
1610 
1611 	sock->domain = READ_ONCE(sqe->fd);
1612 	sock->type = READ_ONCE(sqe->off);
1613 	sock->protocol = READ_ONCE(sqe->len);
1614 	sock->file_slot = READ_ONCE(sqe->file_index);
1615 	sock->nofile = rlimit(RLIMIT_NOFILE);
1616 
1617 	sock->flags = sock->type & ~SOCK_TYPE_MASK;
1618 	if (sock->file_slot && (sock->flags & SOCK_CLOEXEC))
1619 		return -EINVAL;
1620 	if (sock->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
1621 		return -EINVAL;
1622 	return 0;
1623 }
1624 
1625 int io_socket(struct io_kiocb *req, unsigned int issue_flags)
1626 {
1627 	struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
1628 	bool fixed = !!sock->file_slot;
1629 	struct file *file;
1630 	int ret, fd;
1631 
1632 	if (!fixed) {
1633 		fd = __get_unused_fd_flags(sock->flags, sock->nofile);
1634 		if (unlikely(fd < 0))
1635 			return fd;
1636 	}
1637 	file = __sys_socket_file(sock->domain, sock->type, sock->protocol);
1638 	if (IS_ERR(file)) {
1639 		if (!fixed)
1640 			put_unused_fd(fd);
1641 		ret = PTR_ERR(file);
1642 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1643 			return -EAGAIN;
1644 		if (ret == -ERESTARTSYS)
1645 			ret = -EINTR;
1646 		req_set_fail(req);
1647 	} else if (!fixed) {
1648 		fd_install(fd, file);
1649 		ret = fd;
1650 	} else {
1651 		ret = io_fixed_fd_install(req, issue_flags, file,
1652 					    sock->file_slot);
1653 	}
1654 	io_req_set_res(req, ret, 0);
1655 	return IOU_OK;
1656 }
1657 
1658 int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1659 {
1660 	struct io_connect *conn = io_kiocb_to_cmd(req, struct io_connect);
1661 	struct io_async_msghdr *io;
1662 
1663 	if (sqe->len || sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in)
1664 		return -EINVAL;
1665 
1666 	conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
1667 	conn->addr_len =  READ_ONCE(sqe->addr2);
1668 	conn->in_progress = conn->seen_econnaborted = false;
1669 
1670 	io = io_msg_alloc_async(req);
1671 	if (unlikely(!io))
1672 		return -ENOMEM;
1673 
1674 	return move_addr_to_kernel(conn->addr, conn->addr_len, &io->addr);
1675 }
1676 
1677 int io_connect(struct io_kiocb *req, unsigned int issue_flags)
1678 {
1679 	struct io_connect *connect = io_kiocb_to_cmd(req, struct io_connect);
1680 	struct io_async_msghdr *io = req->async_data;
1681 	unsigned file_flags;
1682 	int ret;
1683 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
1684 
1685 	file_flags = force_nonblock ? O_NONBLOCK : 0;
1686 
1687 	ret = __sys_connect_file(req->file, &io->addr, connect->addr_len,
1688 				 file_flags);
1689 	if ((ret == -EAGAIN || ret == -EINPROGRESS || ret == -ECONNABORTED)
1690 	    && force_nonblock) {
1691 		if (ret == -EINPROGRESS) {
1692 			connect->in_progress = true;
1693 		} else if (ret == -ECONNABORTED) {
1694 			if (connect->seen_econnaborted)
1695 				goto out;
1696 			connect->seen_econnaborted = true;
1697 		}
1698 		return -EAGAIN;
1699 	}
1700 	if (connect->in_progress) {
1701 		/*
1702 		 * At least bluetooth will return -EBADFD on a re-connect
1703 		 * attempt, and it's (supposedly) also valid to get -EISCONN
1704 		 * which means the previous result is good. For both of these,
1705 		 * grab the sock_error() and use that for the completion.
1706 		 */
1707 		if (ret == -EBADFD || ret == -EISCONN)
1708 			ret = sock_error(sock_from_file(req->file)->sk);
1709 	}
1710 	if (ret == -ERESTARTSYS)
1711 		ret = -EINTR;
1712 out:
1713 	if (ret < 0)
1714 		req_set_fail(req);
1715 	io_req_msg_cleanup(req, issue_flags);
1716 	io_req_set_res(req, ret, 0);
1717 	return IOU_OK;
1718 }
1719 
1720 void io_netmsg_cache_free(const void *entry)
1721 {
1722 	struct io_async_msghdr *kmsg = (struct io_async_msghdr *) entry;
1723 
1724 	if (kmsg->free_iov) {
1725 		kasan_mempool_unpoison_object(kmsg->free_iov,
1726 				kmsg->free_iov_nr * sizeof(struct iovec));
1727 		io_netmsg_iovec_free(kmsg);
1728 	}
1729 	kfree(kmsg);
1730 }
1731 #endif
1732