1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * common code for virtio vsock
4 *
5 * Copyright (C) 2013-2015 Red Hat, Inc.
6 * Author: Asias He <asias@redhat.com>
7 * Stefan Hajnoczi <stefanha@redhat.com>
8 */
9 #include <linux/spinlock.h>
10 #include <linux/module.h>
11 #include <linux/sched/signal.h>
12 #include <linux/ctype.h>
13 #include <linux/list.h>
14 #include <linux/virtio_vsock.h>
15 #include <uapi/linux/vsockmon.h>
16
17 #include <net/sock.h>
18 #include <net/af_vsock.h>
19
20 #define CREATE_TRACE_POINTS
21 #include <trace/events/vsock_virtio_transport_common.h>
22
23 /* How long to wait for graceful shutdown of a connection */
24 #define VSOCK_CLOSE_TIMEOUT (8 * HZ)
25
26 /* Threshold for detecting small packets to copy */
27 #define GOOD_COPY_LEN 128
28
29 static const struct virtio_transport *
30 virtio_transport_get_ops(struct vsock_sock *vsk)
31 {
32 const struct vsock_transport *t = vsock_core_get_transport(vsk);
33
34 if (WARN_ON(!t))
35 return NULL;
36
37 return container_of(t, struct virtio_transport, transport);
38 }
39
40 static bool virtio_transport_can_zcopy(const struct virtio_transport *t_ops,
41 struct virtio_vsock_pkt_info *info,
42 size_t pkt_len)
43 {
44 struct iov_iter *iov_iter;
45
46 if (!info->msg)
47 return false;
48
49 iov_iter = &info->msg->msg_iter;
50
51 if (iov_iter->iov_offset)
52 return false;
53
54 /* We can't send whole iov. */
55 if (iov_iter->count > pkt_len)
56 return false;
57
58 /* Check that transport can send data in zerocopy mode. */
59 t_ops = virtio_transport_get_ops(info->vsk);
60
61 if (t_ops->can_msgzerocopy) {
62 int pages_to_send = iov_iter_npages(iov_iter, MAX_SKB_FRAGS);
63
64 /* +1 is for packet header. */
65 return t_ops->can_msgzerocopy(pages_to_send + 1);
66 }
67
68 return true;
69 }
70
71 static int virtio_transport_init_zcopy_skb(struct vsock_sock *vsk,
72 struct sk_buff *skb,
73 struct msghdr *msg,
74 bool zerocopy)
75 {
76 struct ubuf_info *uarg;
77
78 if (msg->msg_ubuf) {
79 uarg = msg->msg_ubuf;
80 net_zcopy_get(uarg);
81 } else {
82 struct iov_iter *iter = &msg->msg_iter;
83 struct ubuf_info_msgzc *uarg_zc;
84
85 uarg = msg_zerocopy_realloc(sk_vsock(vsk),
86 iter->count,
87 NULL);
88 if (!uarg)
89 return -1;
90
91 uarg_zc = uarg_to_msgzc(uarg);
92 uarg_zc->zerocopy = zerocopy ? 1 : 0;
93 }
94
95 skb_zcopy_init(skb, uarg);
96
97 return 0;
98 }
99
100 static int virtio_transport_fill_skb(struct sk_buff *skb,
101 struct virtio_vsock_pkt_info *info,
102 size_t len,
103 bool zcopy)
104 {
105 if (zcopy)
106 return __zerocopy_sg_from_iter(info->msg, NULL, skb,
107 &info->msg->msg_iter,
108 len);
109
110 return memcpy_from_msg(skb_put(skb, len), info->msg, len);
111 }
112
113 static void virtio_transport_init_hdr(struct sk_buff *skb,
114 struct virtio_vsock_pkt_info *info,
115 size_t payload_len,
116 u32 src_cid,
117 u32 src_port,
118 u32 dst_cid,
119 u32 dst_port)
120 {
121 struct virtio_vsock_hdr *hdr;
122
123 hdr = virtio_vsock_hdr(skb);
124 hdr->type = cpu_to_le16(info->type);
125 hdr->op = cpu_to_le16(info->op);
126 hdr->src_cid = cpu_to_le64(src_cid);
127 hdr->dst_cid = cpu_to_le64(dst_cid);
128 hdr->src_port = cpu_to_le32(src_port);
129 hdr->dst_port = cpu_to_le32(dst_port);
130 hdr->flags = cpu_to_le32(info->flags);
131 hdr->len = cpu_to_le32(payload_len);
132 hdr->buf_alloc = cpu_to_le32(0);
133 hdr->fwd_cnt = cpu_to_le32(0);
134 }
135
136 static void virtio_transport_copy_nonlinear_skb(const struct sk_buff *skb,
137 void *dst,
138 size_t len)
139 {
140 struct iov_iter iov_iter = { 0 };
141 struct kvec kvec;
142 size_t to_copy;
143
144 kvec.iov_base = dst;
145 kvec.iov_len = len;
146
147 iov_iter.iter_type = ITER_KVEC;
148 iov_iter.kvec = &kvec;
149 iov_iter.nr_segs = 1;
150
151 to_copy = min_t(size_t, len, skb->len);
152
153 skb_copy_datagram_iter(skb, VIRTIO_VSOCK_SKB_CB(skb)->offset,
154 &iov_iter, to_copy);
155 }
156
157 /* Packet capture */
158 static struct sk_buff *virtio_transport_build_skb(void *opaque)
159 {
160 struct virtio_vsock_hdr *pkt_hdr;
161 struct sk_buff *pkt = opaque;
162 struct af_vsockmon_hdr *hdr;
163 struct sk_buff *skb;
164 size_t payload_len;
165
166 /* A packet could be split to fit the RX buffer, so we can retrieve
167 * the payload length from the header and the buffer pointer taking
168 * care of the offset in the original packet.
169 */
170 pkt_hdr = virtio_vsock_hdr(pkt);
171 payload_len = pkt->len;
172
173 skb = alloc_skb(sizeof(*hdr) + sizeof(*pkt_hdr) + payload_len,
174 GFP_ATOMIC);
175 if (!skb)
176 return NULL;
177
178 hdr = skb_put(skb, sizeof(*hdr));
179
180 /* pkt->hdr is little-endian so no need to byteswap here */
181 hdr->src_cid = pkt_hdr->src_cid;
182 hdr->src_port = pkt_hdr->src_port;
183 hdr->dst_cid = pkt_hdr->dst_cid;
184 hdr->dst_port = pkt_hdr->dst_port;
185
186 hdr->transport = cpu_to_le16(AF_VSOCK_TRANSPORT_VIRTIO);
187 hdr->len = cpu_to_le16(sizeof(*pkt_hdr));
188 memset(hdr->reserved, 0, sizeof(hdr->reserved));
189
190 switch (le16_to_cpu(pkt_hdr->op)) {
191 case VIRTIO_VSOCK_OP_REQUEST:
192 case VIRTIO_VSOCK_OP_RESPONSE:
193 hdr->op = cpu_to_le16(AF_VSOCK_OP_CONNECT);
194 break;
195 case VIRTIO_VSOCK_OP_RST:
196 case VIRTIO_VSOCK_OP_SHUTDOWN:
197 hdr->op = cpu_to_le16(AF_VSOCK_OP_DISCONNECT);
198 break;
199 case VIRTIO_VSOCK_OP_RW:
200 hdr->op = cpu_to_le16(AF_VSOCK_OP_PAYLOAD);
201 break;
202 case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
203 case VIRTIO_VSOCK_OP_CREDIT_REQUEST:
204 hdr->op = cpu_to_le16(AF_VSOCK_OP_CONTROL);
205 break;
206 default:
207 hdr->op = cpu_to_le16(AF_VSOCK_OP_UNKNOWN);
208 break;
209 }
210
211 skb_put_data(skb, pkt_hdr, sizeof(*pkt_hdr));
212
213 if (payload_len) {
214 if (skb_is_nonlinear(pkt)) {
215 void *data = skb_put(skb, payload_len);
216
217 virtio_transport_copy_nonlinear_skb(pkt, data, payload_len);
218 } else {
219 skb_put_data(skb, pkt->data, payload_len);
220 }
221 }
222
223 return skb;
224 }
225
226 void virtio_transport_deliver_tap_pkt(struct sk_buff *skb)
227 {
228 if (virtio_vsock_skb_tap_delivered(skb))
229 return;
230
231 vsock_deliver_tap(virtio_transport_build_skb, skb);
232 virtio_vsock_skb_set_tap_delivered(skb);
233 }
234 EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt);
235
236 static u16 virtio_transport_get_type(struct sock *sk)
237 {
238 if (sk->sk_type == SOCK_STREAM)
239 return VIRTIO_VSOCK_TYPE_STREAM;
240 else
241 return VIRTIO_VSOCK_TYPE_SEQPACKET;
242 }
243
244 /* Returns new sk_buff on success, otherwise returns NULL. */
245 static struct sk_buff *virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
246 size_t payload_len,
247 bool zcopy,
248 u32 src_cid,
249 u32 src_port,
250 u32 dst_cid,
251 u32 dst_port)
252 {
253 struct vsock_sock *vsk;
254 struct sk_buff *skb;
255 size_t skb_len;
256
257 skb_len = VIRTIO_VSOCK_SKB_HEADROOM;
258
259 if (!zcopy)
260 skb_len += payload_len;
261
262 skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL);
263 if (!skb)
264 return NULL;
265
266 virtio_transport_init_hdr(skb, info, payload_len, src_cid, src_port,
267 dst_cid, dst_port);
268
269 vsk = info->vsk;
270
271 /* If 'vsk' != NULL then payload is always present, so we
272 * will never call '__zerocopy_sg_from_iter()' below without
273 * setting skb owner in 'skb_set_owner_w()'. The only case
274 * when 'vsk' == NULL is VIRTIO_VSOCK_OP_RST control message
275 * without payload.
276 */
277 WARN_ON_ONCE(!(vsk && (info->msg && payload_len)) && zcopy);
278
279 /* Set owner here, because '__zerocopy_sg_from_iter()' uses
280 * owner of skb without check to update 'sk_wmem_alloc'.
281 */
282 if (vsk)
283 skb_set_owner_w(skb, sk_vsock(vsk));
284
285 if (info->msg && payload_len > 0) {
286 int err;
287
288 err = virtio_transport_fill_skb(skb, info, payload_len, zcopy);
289 if (err)
290 goto out;
291
292 if (msg_data_left(info->msg) == 0 &&
293 info->type == VIRTIO_VSOCK_TYPE_SEQPACKET) {
294 struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
295
296 hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
297
298 if (info->msg->msg_flags & MSG_EOR)
299 hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
300 }
301 }
302
303 if (info->reply)
304 virtio_vsock_skb_set_reply(skb);
305
306 trace_virtio_transport_alloc_pkt(src_cid, src_port,
307 dst_cid, dst_port,
308 payload_len,
309 info->type,
310 info->op,
311 info->flags,
312 zcopy);
313
314 return skb;
315 out:
316 kfree_skb(skb);
317 return NULL;
318 }
319
320 /* This function can only be used on connecting/connected sockets,
321 * since a socket assigned to a transport is required.
322 *
323 * Do not use on listener sockets!
324 */
325 static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
326 struct virtio_vsock_pkt_info *info)
327 {
328 u32 max_skb_len = VIRTIO_VSOCK_MAX_PKT_BUF_SIZE;
329 u32 src_cid, src_port, dst_cid, dst_port;
330 const struct virtio_transport *t_ops;
331 struct virtio_vsock_sock *vvs;
332 u32 pkt_len = info->pkt_len;
333 bool can_zcopy = false;
334 u32 rest_len;
335 int ret;
336
337 info->type = virtio_transport_get_type(sk_vsock(vsk));
338
339 t_ops = virtio_transport_get_ops(vsk);
340 if (unlikely(!t_ops))
341 return -EFAULT;
342
343 src_cid = t_ops->transport.get_local_cid();
344 src_port = vsk->local_addr.svm_port;
345 if (!info->remote_cid) {
346 dst_cid = vsk->remote_addr.svm_cid;
347 dst_port = vsk->remote_addr.svm_port;
348 } else {
349 dst_cid = info->remote_cid;
350 dst_port = info->remote_port;
351 }
352
353 vvs = vsk->trans;
354
355 /* virtio_transport_get_credit might return less than pkt_len credit */
356 pkt_len = virtio_transport_get_credit(vvs, pkt_len);
357
358 /* Do not send zero length OP_RW pkt */
359 if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
360 return pkt_len;
361
362 if (info->msg) {
363 /* If zerocopy is not enabled by 'setsockopt()', we behave as
364 * there is no MSG_ZEROCOPY flag set.
365 */
366 if (!sock_flag(sk_vsock(vsk), SOCK_ZEROCOPY))
367 info->msg->msg_flags &= ~MSG_ZEROCOPY;
368
369 if (info->msg->msg_flags & MSG_ZEROCOPY)
370 can_zcopy = virtio_transport_can_zcopy(t_ops, info, pkt_len);
371
372 if (can_zcopy)
373 max_skb_len = min_t(u32, VIRTIO_VSOCK_MAX_PKT_BUF_SIZE,
374 (MAX_SKB_FRAGS * PAGE_SIZE));
375 }
376
377 rest_len = pkt_len;
378
379 do {
380 struct sk_buff *skb;
381 size_t skb_len;
382
383 skb_len = min(max_skb_len, rest_len);
384
385 skb = virtio_transport_alloc_skb(info, skb_len, can_zcopy,
386 src_cid, src_port,
387 dst_cid, dst_port);
388 if (!skb) {
389 ret = -ENOMEM;
390 break;
391 }
392
393 /* We process buffer part by part, allocating skb on
394 * each iteration. If this is last skb for this buffer
395 * and MSG_ZEROCOPY mode is in use - we must allocate
396 * completion for the current syscall.
397 */
398 if (info->msg && info->msg->msg_flags & MSG_ZEROCOPY &&
399 skb_len == rest_len && info->op == VIRTIO_VSOCK_OP_RW) {
400 if (virtio_transport_init_zcopy_skb(vsk, skb,
401 info->msg,
402 can_zcopy)) {
403 ret = -ENOMEM;
404 break;
405 }
406 }
407
408 virtio_transport_inc_tx_pkt(vvs, skb);
409
410 ret = t_ops->send_pkt(skb);
411 if (ret < 0)
412 break;
413
414 /* Both virtio and vhost 'send_pkt()' returns 'skb_len',
415 * but for reliability use 'ret' instead of 'skb_len'.
416 * Also if partial send happens (e.g. 'ret' != 'skb_len')
417 * somehow, we break this loop, but account such returned
418 * value in 'virtio_transport_put_credit()'.
419 */
420 rest_len -= ret;
421
422 if (WARN_ONCE(ret != skb_len,
423 "'send_pkt()' returns %i, but %zu expected\n",
424 ret, skb_len))
425 break;
426 } while (rest_len);
427
428 virtio_transport_put_credit(vvs, rest_len);
429
430 /* Return number of bytes, if any data has been sent. */
431 if (rest_len != pkt_len)
432 ret = pkt_len - rest_len;
433
434 return ret;
435 }
436
437 static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,
438 u32 len)
439 {
440 if (vvs->rx_bytes + len > vvs->buf_alloc)
441 return false;
442
443 vvs->rx_bytes += len;
444 return true;
445 }
446
447 static void virtio_transport_dec_rx_pkt(struct virtio_vsock_sock *vvs,
448 u32 len)
449 {
450 vvs->rx_bytes -= len;
451 vvs->fwd_cnt += len;
452 }
453
454 void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct sk_buff *skb)
455 {
456 struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
457
458 spin_lock_bh(&vvs->rx_lock);
459 vvs->last_fwd_cnt = vvs->fwd_cnt;
460 hdr->fwd_cnt = cpu_to_le32(vvs->fwd_cnt);
461 hdr->buf_alloc = cpu_to_le32(vvs->buf_alloc);
462 spin_unlock_bh(&vvs->rx_lock);
463 }
464 EXPORT_SYMBOL_GPL(virtio_transport_inc_tx_pkt);
465
466 u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 credit)
467 {
468 u32 ret;
469
470 if (!credit)
471 return 0;
472
473 spin_lock_bh(&vvs->tx_lock);
474 ret = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
475 if (ret > credit)
476 ret = credit;
477 vvs->tx_cnt += ret;
478 spin_unlock_bh(&vvs->tx_lock);
479
480 return ret;
481 }
482 EXPORT_SYMBOL_GPL(virtio_transport_get_credit);
483
484 void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit)
485 {
486 if (!credit)
487 return;
488
489 spin_lock_bh(&vvs->tx_lock);
490 vvs->tx_cnt -= credit;
491 spin_unlock_bh(&vvs->tx_lock);
492 }
493 EXPORT_SYMBOL_GPL(virtio_transport_put_credit);
494
495 static int virtio_transport_send_credit_update(struct vsock_sock *vsk)
496 {
497 struct virtio_vsock_pkt_info info = {
498 .op = VIRTIO_VSOCK_OP_CREDIT_UPDATE,
499 .vsk = vsk,
500 };
501
502 return virtio_transport_send_pkt_info(vsk, &info);
503 }
504
505 static ssize_t
506 virtio_transport_stream_do_peek(struct vsock_sock *vsk,
507 struct msghdr *msg,
508 size_t len)
509 {
510 struct virtio_vsock_sock *vvs = vsk->trans;
511 struct sk_buff *skb;
512 size_t total = 0;
513 int err;
514
515 spin_lock_bh(&vvs->rx_lock);
516
517 skb_queue_walk(&vvs->rx_queue, skb) {
518 size_t bytes;
519
520 bytes = len - total;
521 if (bytes > skb->len)
522 bytes = skb->len;
523
524 spin_unlock_bh(&vvs->rx_lock);
525
526 /* sk_lock is held by caller so no one else can dequeue.
527 * Unlock rx_lock since skb_copy_datagram_iter() may sleep.
528 */
529 err = skb_copy_datagram_iter(skb, VIRTIO_VSOCK_SKB_CB(skb)->offset,
530 &msg->msg_iter, bytes);
531 if (err)
532 goto out;
533
534 total += bytes;
535
536 spin_lock_bh(&vvs->rx_lock);
537
538 if (total == len)
539 break;
540 }
541
542 spin_unlock_bh(&vvs->rx_lock);
543
544 return total;
545
546 out:
547 if (total)
548 err = total;
549 return err;
550 }
551
552 static ssize_t
553 virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
554 struct msghdr *msg,
555 size_t len)
556 {
557 struct virtio_vsock_sock *vvs = vsk->trans;
558 size_t bytes, total = 0;
559 struct sk_buff *skb;
560 u32 fwd_cnt_delta;
561 bool low_rx_bytes;
562 int err = -EFAULT;
563 u32 free_space;
564
565 spin_lock_bh(&vvs->rx_lock);
566
567 if (WARN_ONCE(skb_queue_empty(&vvs->rx_queue) && vvs->rx_bytes,
568 "rx_queue is empty, but rx_bytes is non-zero\n")) {
569 spin_unlock_bh(&vvs->rx_lock);
570 return err;
571 }
572
573 while (total < len && !skb_queue_empty(&vvs->rx_queue)) {
574 skb = skb_peek(&vvs->rx_queue);
575
576 bytes = min_t(size_t, len - total,
577 skb->len - VIRTIO_VSOCK_SKB_CB(skb)->offset);
578
579 /* sk_lock is held by caller so no one else can dequeue.
580 * Unlock rx_lock since skb_copy_datagram_iter() may sleep.
581 */
582 spin_unlock_bh(&vvs->rx_lock);
583
584 err = skb_copy_datagram_iter(skb,
585 VIRTIO_VSOCK_SKB_CB(skb)->offset,
586 &msg->msg_iter, bytes);
587 if (err)
588 goto out;
589
590 spin_lock_bh(&vvs->rx_lock);
591
592 total += bytes;
593
594 VIRTIO_VSOCK_SKB_CB(skb)->offset += bytes;
595
596 if (skb->len == VIRTIO_VSOCK_SKB_CB(skb)->offset) {
597 u32 pkt_len = le32_to_cpu(virtio_vsock_hdr(skb)->len);
598
599 virtio_transport_dec_rx_pkt(vvs, pkt_len);
600 __skb_unlink(skb, &vvs->rx_queue);
601 consume_skb(skb);
602 }
603 }
604
605 fwd_cnt_delta = vvs->fwd_cnt - vvs->last_fwd_cnt;
606 free_space = vvs->buf_alloc - fwd_cnt_delta;
607 low_rx_bytes = (vvs->rx_bytes <
608 sock_rcvlowat(sk_vsock(vsk), 0, INT_MAX));
609
610 spin_unlock_bh(&vvs->rx_lock);
611
612 /* To reduce the number of credit update messages,
613 * don't update credits as long as lots of space is available.
614 * Note: the limit chosen here is arbitrary. Setting the limit
615 * too high causes extra messages. Too low causes transmitter
616 * stalls. As stalls are in theory more expensive than extra
617 * messages, we set the limit to a high value. TODO: experiment
618 * with different values. Also send credit update message when
619 * number of bytes in rx queue is not enough to wake up reader.
620 */
621 if (fwd_cnt_delta &&
622 (free_space < VIRTIO_VSOCK_MAX_PKT_BUF_SIZE || low_rx_bytes))
623 virtio_transport_send_credit_update(vsk);
624
625 return total;
626
627 out:
628 if (total)
629 err = total;
630 return err;
631 }
632
633 static ssize_t
634 virtio_transport_seqpacket_do_peek(struct vsock_sock *vsk,
635 struct msghdr *msg)
636 {
637 struct virtio_vsock_sock *vvs = vsk->trans;
638 struct sk_buff *skb;
639 size_t total, len;
640
641 spin_lock_bh(&vvs->rx_lock);
642
643 if (!vvs->msg_count) {
644 spin_unlock_bh(&vvs->rx_lock);
645 return 0;
646 }
647
648 total = 0;
649 len = msg_data_left(msg);
650
651 skb_queue_walk(&vvs->rx_queue, skb) {
652 struct virtio_vsock_hdr *hdr;
653
654 if (total < len) {
655 size_t bytes;
656 int err;
657
658 bytes = len - total;
659 if (bytes > skb->len)
660 bytes = skb->len;
661
662 spin_unlock_bh(&vvs->rx_lock);
663
664 /* sk_lock is held by caller so no one else can dequeue.
665 * Unlock rx_lock since skb_copy_datagram_iter() may sleep.
666 */
667 err = skb_copy_datagram_iter(skb, VIRTIO_VSOCK_SKB_CB(skb)->offset,
668 &msg->msg_iter, bytes);
669 if (err)
670 return err;
671
672 spin_lock_bh(&vvs->rx_lock);
673 }
674
675 total += skb->len;
676 hdr = virtio_vsock_hdr(skb);
677
678 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {
679 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR)
680 msg->msg_flags |= MSG_EOR;
681
682 break;
683 }
684 }
685
686 spin_unlock_bh(&vvs->rx_lock);
687
688 return total;
689 }
690
691 static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
692 struct msghdr *msg,
693 int flags)
694 {
695 struct virtio_vsock_sock *vvs = vsk->trans;
696 int dequeued_len = 0;
697 size_t user_buf_len = msg_data_left(msg);
698 bool msg_ready = false;
699 struct sk_buff *skb;
700
701 spin_lock_bh(&vvs->rx_lock);
702
703 if (vvs->msg_count == 0) {
704 spin_unlock_bh(&vvs->rx_lock);
705 return 0;
706 }
707
708 while (!msg_ready) {
709 struct virtio_vsock_hdr *hdr;
710 size_t pkt_len;
711
712 skb = __skb_dequeue(&vvs->rx_queue);
713 if (!skb)
714 break;
715 hdr = virtio_vsock_hdr(skb);
716 pkt_len = (size_t)le32_to_cpu(hdr->len);
717
718 if (dequeued_len >= 0) {
719 size_t bytes_to_copy;
720
721 bytes_to_copy = min(user_buf_len, pkt_len);
722
723 if (bytes_to_copy) {
724 int err;
725
726 /* sk_lock is held by caller so no one else can dequeue.
727 * Unlock rx_lock since skb_copy_datagram_iter() may sleep.
728 */
729 spin_unlock_bh(&vvs->rx_lock);
730
731 err = skb_copy_datagram_iter(skb, 0,
732 &msg->msg_iter,
733 bytes_to_copy);
734 if (err) {
735 /* Copy of message failed. Rest of
736 * fragments will be freed without copy.
737 */
738 dequeued_len = err;
739 } else {
740 user_buf_len -= bytes_to_copy;
741 }
742
743 spin_lock_bh(&vvs->rx_lock);
744 }
745
746 if (dequeued_len >= 0)
747 dequeued_len += pkt_len;
748 }
749
750 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {
751 msg_ready = true;
752 vvs->msg_count--;
753
754 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR)
755 msg->msg_flags |= MSG_EOR;
756 }
757
758 virtio_transport_dec_rx_pkt(vvs, pkt_len);
759 kfree_skb(skb);
760 }
761
762 spin_unlock_bh(&vvs->rx_lock);
763
764 virtio_transport_send_credit_update(vsk);
765
766 return dequeued_len;
767 }
768
769 ssize_t
770 virtio_transport_stream_dequeue(struct vsock_sock *vsk,
771 struct msghdr *msg,
772 size_t len, int flags)
773 {
774 if (flags & MSG_PEEK)
775 return virtio_transport_stream_do_peek(vsk, msg, len);
776 else
777 return virtio_transport_stream_do_dequeue(vsk, msg, len);
778 }
779 EXPORT_SYMBOL_GPL(virtio_transport_stream_dequeue);
780
781 ssize_t
782 virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
783 struct msghdr *msg,
784 int flags)
785 {
786 if (flags & MSG_PEEK)
787 return virtio_transport_seqpacket_do_peek(vsk, msg);
788 else
789 return virtio_transport_seqpacket_do_dequeue(vsk, msg, flags);
790 }
791 EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);
792
793 int
794 virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,
795 struct msghdr *msg,
796 size_t len)
797 {
798 struct virtio_vsock_sock *vvs = vsk->trans;
799
800 spin_lock_bh(&vvs->tx_lock);
801
802 if (len > vvs->peer_buf_alloc) {
803 spin_unlock_bh(&vvs->tx_lock);
804 return -EMSGSIZE;
805 }
806
807 spin_unlock_bh(&vvs->tx_lock);
808
809 return virtio_transport_stream_enqueue(vsk, msg, len);
810 }
811 EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_enqueue);
812
813 int
814 virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
815 struct msghdr *msg,
816 size_t len, int flags)
817 {
818 return -EOPNOTSUPP;
819 }
820 EXPORT_SYMBOL_GPL(virtio_transport_dgram_dequeue);
821
822 s64 virtio_transport_stream_has_data(struct vsock_sock *vsk)
823 {
824 struct virtio_vsock_sock *vvs = vsk->trans;
825 s64 bytes;
826
827 spin_lock_bh(&vvs->rx_lock);
828 bytes = vvs->rx_bytes;
829 spin_unlock_bh(&vvs->rx_lock);
830
831 return bytes;
832 }
833 EXPORT_SYMBOL_GPL(virtio_transport_stream_has_data);
834
835 u32 virtio_transport_seqpacket_has_data(struct vsock_sock *vsk)
836 {
837 struct virtio_vsock_sock *vvs = vsk->trans;
838 u32 msg_count;
839
840 spin_lock_bh(&vvs->rx_lock);
841 msg_count = vvs->msg_count;
842 spin_unlock_bh(&vvs->rx_lock);
843
844 return msg_count;
845 }
846 EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_has_data);
847
848 static s64 virtio_transport_has_space(struct vsock_sock *vsk)
849 {
850 struct virtio_vsock_sock *vvs = vsk->trans;
851 s64 bytes;
852
853 bytes = (s64)vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
854 if (bytes < 0)
855 bytes = 0;
856
857 return bytes;
858 }
859
860 s64 virtio_transport_stream_has_space(struct vsock_sock *vsk)
861 {
862 struct virtio_vsock_sock *vvs = vsk->trans;
863 s64 bytes;
864
865 spin_lock_bh(&vvs->tx_lock);
866 bytes = virtio_transport_has_space(vsk);
867 spin_unlock_bh(&vvs->tx_lock);
868
869 return bytes;
870 }
871 EXPORT_SYMBOL_GPL(virtio_transport_stream_has_space);
872
873 int virtio_transport_do_socket_init(struct vsock_sock *vsk,
874 struct vsock_sock *psk)
875 {
876 struct virtio_vsock_sock *vvs;
877
878 vvs = kzalloc(sizeof(*vvs), GFP_KERNEL);
879 if (!vvs)
880 return -ENOMEM;
881
882 vsk->trans = vvs;
883 vvs->vsk = vsk;
884 if (psk && psk->trans) {
885 struct virtio_vsock_sock *ptrans = psk->trans;
886
887 vvs->peer_buf_alloc = ptrans->peer_buf_alloc;
888 }
889
890 if (vsk->buffer_size > VIRTIO_VSOCK_MAX_BUF_SIZE)
891 vsk->buffer_size = VIRTIO_VSOCK_MAX_BUF_SIZE;
892
893 vvs->buf_alloc = vsk->buffer_size;
894
895 spin_lock_init(&vvs->rx_lock);
896 spin_lock_init(&vvs->tx_lock);
897 skb_queue_head_init(&vvs->rx_queue);
898
899 return 0;
900 }
901 EXPORT_SYMBOL_GPL(virtio_transport_do_socket_init);
902
903 /* sk_lock held by the caller */
904 void virtio_transport_notify_buffer_size(struct vsock_sock *vsk, u64 *val)
905 {
906 struct virtio_vsock_sock *vvs = vsk->trans;
907
908 if (*val > VIRTIO_VSOCK_MAX_BUF_SIZE)
909 *val = VIRTIO_VSOCK_MAX_BUF_SIZE;
910
911 vvs->buf_alloc = *val;
912
913 virtio_transport_send_credit_update(vsk);
914 }
915 EXPORT_SYMBOL_GPL(virtio_transport_notify_buffer_size);
916
917 int
918 virtio_transport_notify_poll_in(struct vsock_sock *vsk,
919 size_t target,
920 bool *data_ready_now)
921 {
922 *data_ready_now = vsock_stream_has_data(vsk) >= target;
923
924 return 0;
925 }
926 EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_in);
927
928 int
929 virtio_transport_notify_poll_out(struct vsock_sock *vsk,
930 size_t target,
931 bool *space_avail_now)
932 {
933 s64 free_space;
934
935 free_space = vsock_stream_has_space(vsk);
936 if (free_space > 0)
937 *space_avail_now = true;
938 else if (free_space == 0)
939 *space_avail_now = false;
940
941 return 0;
942 }
943 EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_out);
944
945 int virtio_transport_notify_recv_init(struct vsock_sock *vsk,
946 size_t target, struct vsock_transport_recv_notify_data *data)
947 {
948 return 0;
949 }
950 EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_init);
951
952 int virtio_transport_notify_recv_pre_block(struct vsock_sock *vsk,
953 size_t target, struct vsock_transport_recv_notify_data *data)
954 {
955 return 0;
956 }
957 EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_block);
958
959 int virtio_transport_notify_recv_pre_dequeue(struct vsock_sock *vsk,
960 size_t target, struct vsock_transport_recv_notify_data *data)
961 {
962 return 0;
963 }
964 EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_dequeue);
965
966 int virtio_transport_notify_recv_post_dequeue(struct vsock_sock *vsk,
967 size_t target, ssize_t copied, bool data_read,
968 struct vsock_transport_recv_notify_data *data)
969 {
970 return 0;
971 }
972 EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_post_dequeue);
973
974 int virtio_transport_notify_send_init(struct vsock_sock *vsk,
975 struct vsock_transport_send_notify_data *data)
976 {
977 return 0;
978 }
979 EXPORT_SYMBOL_GPL(virtio_transport_notify_send_init);
980
981 int virtio_transport_notify_send_pre_block(struct vsock_sock *vsk,
982 struct vsock_transport_send_notify_data *data)
983 {
984 return 0;
985 }
986 EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_block);
987
988 int virtio_transport_notify_send_pre_enqueue(struct vsock_sock *vsk,
989 struct vsock_transport_send_notify_data *data)
990 {
991 return 0;
992 }
993 EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_enqueue);
994
995 int virtio_transport_notify_send_post_enqueue(struct vsock_sock *vsk,
996 ssize_t written, struct vsock_transport_send_notify_data *data)
997 {
998 return 0;
999 }
1000 EXPORT_SYMBOL_GPL(virtio_transport_notify_send_post_enqueue);
1001
1002 u64 virtio_transport_stream_rcvhiwat(struct vsock_sock *vsk)
1003 {
1004 return vsk->buffer_size;
1005 }
1006 EXPORT_SYMBOL_GPL(virtio_transport_stream_rcvhiwat);
1007
1008 bool virtio_transport_stream_is_active(struct vsock_sock *vsk)
1009 {
1010 return true;
1011 }
1012 EXPORT_SYMBOL_GPL(virtio_transport_stream_is_active);
1013
1014 bool virtio_transport_stream_allow(u32 cid, u32 port)
1015 {
1016 return true;
1017 }
1018 EXPORT_SYMBOL_GPL(virtio_transport_stream_allow);
1019
1020 int virtio_transport_dgram_bind(struct vsock_sock *vsk,
1021 struct sockaddr_vm *addr)
1022 {
1023 return -EOPNOTSUPP;
1024 }
1025 EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind);
1026
1027 bool virtio_transport_dgram_allow(u32 cid, u32 port)
1028 {
1029 return false;
1030 }
1031 EXPORT_SYMBOL_GPL(virtio_transport_dgram_allow);
1032
1033 int virtio_transport_connect(struct vsock_sock *vsk)
1034 {
1035 struct virtio_vsock_pkt_info info = {
1036 .op = VIRTIO_VSOCK_OP_REQUEST,
1037 .vsk = vsk,
1038 };
1039
1040 return virtio_transport_send_pkt_info(vsk, &info);
1041 }
1042 EXPORT_SYMBOL_GPL(virtio_transport_connect);
1043
1044 int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
1045 {
1046 struct virtio_vsock_pkt_info info = {
1047 .op = VIRTIO_VSOCK_OP_SHUTDOWN,
1048 .flags = (mode & RCV_SHUTDOWN ?
1049 VIRTIO_VSOCK_SHUTDOWN_RCV : 0) |
1050 (mode & SEND_SHUTDOWN ?
1051 VIRTIO_VSOCK_SHUTDOWN_SEND : 0),
1052 .vsk = vsk,
1053 };
1054
1055 return virtio_transport_send_pkt_info(vsk, &info);
1056 }
1057 EXPORT_SYMBOL_GPL(virtio_transport_shutdown);
1058
1059 int
1060 virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
1061 struct sockaddr_vm *remote_addr,
1062 struct msghdr *msg,
1063 size_t dgram_len)
1064 {
1065 return -EOPNOTSUPP;
1066 }
1067 EXPORT_SYMBOL_GPL(virtio_transport_dgram_enqueue);
1068
1069 ssize_t
1070 virtio_transport_stream_enqueue(struct vsock_sock *vsk,
1071 struct msghdr *msg,
1072 size_t len)
1073 {
1074 struct virtio_vsock_pkt_info info = {
1075 .op = VIRTIO_VSOCK_OP_RW,
1076 .msg = msg,
1077 .pkt_len = len,
1078 .vsk = vsk,
1079 };
1080
1081 return virtio_transport_send_pkt_info(vsk, &info);
1082 }
1083 EXPORT_SYMBOL_GPL(virtio_transport_stream_enqueue);
1084
1085 void virtio_transport_destruct(struct vsock_sock *vsk)
1086 {
1087 struct virtio_vsock_sock *vvs = vsk->trans;
1088
1089 kfree(vvs);
1090 }
1091 EXPORT_SYMBOL_GPL(virtio_transport_destruct);
1092
1093 static int virtio_transport_reset(struct vsock_sock *vsk,
1094 struct sk_buff *skb)
1095 {
1096 struct virtio_vsock_pkt_info info = {
1097 .op = VIRTIO_VSOCK_OP_RST,
1098 .reply = !!skb,
1099 .vsk = vsk,
1100 };
1101
1102 /* Send RST only if the original pkt is not a RST pkt */
1103 if (skb && le16_to_cpu(virtio_vsock_hdr(skb)->op) == VIRTIO_VSOCK_OP_RST)
1104 return 0;
1105
1106 return virtio_transport_send_pkt_info(vsk, &info);
1107 }
1108
1109 /* Normally packets are associated with a socket. There may be no socket if an
1110 * attempt was made to connect to a socket that does not exist.
1111 */
1112 static int virtio_transport_reset_no_sock(const struct virtio_transport *t,
1113 struct sk_buff *skb)
1114 {
1115 struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1116 struct virtio_vsock_pkt_info info = {
1117 .op = VIRTIO_VSOCK_OP_RST,
1118 .type = le16_to_cpu(hdr->type),
1119 .reply = true,
1120 };
1121 struct sk_buff *reply;
1122
1123 /* Send RST only if the original pkt is not a RST pkt */
1124 if (le16_to_cpu(hdr->op) == VIRTIO_VSOCK_OP_RST)
1125 return 0;
1126
1127 if (!t)
1128 return -ENOTCONN;
1129
1130 reply = virtio_transport_alloc_skb(&info, 0, false,
1131 le64_to_cpu(hdr->dst_cid),
1132 le32_to_cpu(hdr->dst_port),
1133 le64_to_cpu(hdr->src_cid),
1134 le32_to_cpu(hdr->src_port));
1135 if (!reply)
1136 return -ENOMEM;
1137
1138 return t->send_pkt(reply);
1139 }
1140
1141 /* This function should be called with sk_lock held and SOCK_DONE set */
1142 static void virtio_transport_remove_sock(struct vsock_sock *vsk)
1143 {
1144 struct virtio_vsock_sock *vvs = vsk->trans;
1145
1146 /* We don't need to take rx_lock, as the socket is closing and we are
1147 * removing it.
1148 */
1149 __skb_queue_purge(&vvs->rx_queue);
1150 vsock_remove_sock(vsk);
1151 }
1152
1153 static void virtio_transport_wait_close(struct sock *sk, long timeout)
1154 {
1155 if (timeout) {
1156 DEFINE_WAIT_FUNC(wait, woken_wake_function);
1157
1158 add_wait_queue(sk_sleep(sk), &wait);
1159
1160 do {
1161 if (sk_wait_event(sk, &timeout,
1162 sock_flag(sk, SOCK_DONE), &wait))
1163 break;
1164 } while (!signal_pending(current) && timeout);
1165
1166 remove_wait_queue(sk_sleep(sk), &wait);
1167 }
1168 }
1169
1170 static void virtio_transport_do_close(struct vsock_sock *vsk,
1171 bool cancel_timeout)
1172 {
1173 struct sock *sk = sk_vsock(vsk);
1174
1175 sock_set_flag(sk, SOCK_DONE);
1176 vsk->peer_shutdown = SHUTDOWN_MASK;
1177 if (vsock_stream_has_data(vsk) <= 0)
1178 sk->sk_state = TCP_CLOSING;
1179 sk->sk_state_change(sk);
1180
1181 if (vsk->close_work_scheduled &&
1182 (!cancel_timeout || cancel_delayed_work(&vsk->close_work))) {
1183 vsk->close_work_scheduled = false;
1184
1185 virtio_transport_remove_sock(vsk);
1186
1187 /* Release refcnt obtained when we scheduled the timeout */
1188 sock_put(sk);
1189 }
1190 }
1191
1192 static void virtio_transport_close_timeout(struct work_struct *work)
1193 {
1194 struct vsock_sock *vsk =
1195 container_of(work, struct vsock_sock, close_work.work);
1196 struct sock *sk = sk_vsock(vsk);
1197
1198 sock_hold(sk);
1199 lock_sock(sk);
1200
1201 if (!sock_flag(sk, SOCK_DONE)) {
1202 (void)virtio_transport_reset(vsk, NULL);
1203
1204 virtio_transport_do_close(vsk, false);
1205 }
1206
1207 vsk->close_work_scheduled = false;
1208
1209 release_sock(sk);
1210 sock_put(sk);
1211 }
1212
1213 /* User context, vsk->sk is locked */
1214 static bool virtio_transport_close(struct vsock_sock *vsk)
1215 {
1216 struct sock *sk = &vsk->sk;
1217
1218 if (!(sk->sk_state == TCP_ESTABLISHED ||
1219 sk->sk_state == TCP_CLOSING))
1220 return true;
1221
1222 /* Already received SHUTDOWN from peer, reply with RST */
1223 if ((vsk->peer_shutdown & SHUTDOWN_MASK) == SHUTDOWN_MASK) {
1224 (void)virtio_transport_reset(vsk, NULL);
1225 return true;
1226 }
1227
1228 if ((sk->sk_shutdown & SHUTDOWN_MASK) != SHUTDOWN_MASK)
1229 (void)virtio_transport_shutdown(vsk, SHUTDOWN_MASK);
1230
1231 if (sock_flag(sk, SOCK_LINGER) && !(current->flags & PF_EXITING))
1232 virtio_transport_wait_close(sk, sk->sk_lingertime);
1233
1234 if (sock_flag(sk, SOCK_DONE)) {
1235 return true;
1236 }
1237
1238 sock_hold(sk);
1239 INIT_DELAYED_WORK(&vsk->close_work,
1240 virtio_transport_close_timeout);
1241 vsk->close_work_scheduled = true;
1242 schedule_delayed_work(&vsk->close_work, VSOCK_CLOSE_TIMEOUT);
1243 return false;
1244 }
1245
1246 void virtio_transport_release(struct vsock_sock *vsk)
1247 {
1248 struct sock *sk = &vsk->sk;
1249 bool remove_sock = true;
1250
1251 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)
1252 remove_sock = virtio_transport_close(vsk);
1253
1254 if (remove_sock) {
1255 sock_set_flag(sk, SOCK_DONE);
1256 virtio_transport_remove_sock(vsk);
1257 }
1258 }
1259 EXPORT_SYMBOL_GPL(virtio_transport_release);
1260
1261 static int
1262 virtio_transport_recv_connecting(struct sock *sk,
1263 struct sk_buff *skb)
1264 {
1265 struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1266 struct vsock_sock *vsk = vsock_sk(sk);
1267 int skerr;
1268 int err;
1269
1270 switch (le16_to_cpu(hdr->op)) {
1271 case VIRTIO_VSOCK_OP_RESPONSE:
1272 sk->sk_state = TCP_ESTABLISHED;
1273 sk->sk_socket->state = SS_CONNECTED;
1274 vsock_insert_connected(vsk);
1275 sk->sk_state_change(sk);
1276 break;
1277 case VIRTIO_VSOCK_OP_INVALID:
1278 break;
1279 case VIRTIO_VSOCK_OP_RST:
1280 skerr = ECONNRESET;
1281 err = 0;
1282 goto destroy;
1283 default:
1284 skerr = EPROTO;
1285 err = -EINVAL;
1286 goto destroy;
1287 }
1288 return 0;
1289
1290 destroy:
1291 virtio_transport_reset(vsk, skb);
1292 sk->sk_state = TCP_CLOSE;
1293 sk->sk_err = skerr;
1294 sk_error_report(sk);
1295 return err;
1296 }
1297
1298 static void
1299 virtio_transport_recv_enqueue(struct vsock_sock *vsk,
1300 struct sk_buff *skb)
1301 {
1302 struct virtio_vsock_sock *vvs = vsk->trans;
1303 bool can_enqueue, free_pkt = false;
1304 struct virtio_vsock_hdr *hdr;
1305 u32 len;
1306
1307 hdr = virtio_vsock_hdr(skb);
1308 len = le32_to_cpu(hdr->len);
1309
1310 spin_lock_bh(&vvs->rx_lock);
1311
1312 can_enqueue = virtio_transport_inc_rx_pkt(vvs, len);
1313 if (!can_enqueue) {
1314 free_pkt = true;
1315 goto out;
1316 }
1317
1318 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM)
1319 vvs->msg_count++;
1320
1321 /* Try to copy small packets into the buffer of last packet queued,
1322 * to avoid wasting memory queueing the entire buffer with a small
1323 * payload.
1324 */
1325 if (len <= GOOD_COPY_LEN && !skb_queue_empty(&vvs->rx_queue)) {
1326 struct virtio_vsock_hdr *last_hdr;
1327 struct sk_buff *last_skb;
1328
1329 last_skb = skb_peek_tail(&vvs->rx_queue);
1330 last_hdr = virtio_vsock_hdr(last_skb);
1331
1332 /* If there is space in the last packet queued, we copy the
1333 * new packet in its buffer. We avoid this if the last packet
1334 * queued has VIRTIO_VSOCK_SEQ_EOM set, because this is
1335 * delimiter of SEQPACKET message, so 'pkt' is the first packet
1336 * of a new message.
1337 */
1338 if (skb->len < skb_tailroom(last_skb) &&
1339 !(le32_to_cpu(last_hdr->flags) & VIRTIO_VSOCK_SEQ_EOM)) {
1340 memcpy(skb_put(last_skb, skb->len), skb->data, skb->len);
1341 free_pkt = true;
1342 last_hdr->flags |= hdr->flags;
1343 le32_add_cpu(&last_hdr->len, len);
1344 goto out;
1345 }
1346 }
1347
1348 __skb_queue_tail(&vvs->rx_queue, skb);
1349
1350 out:
1351 spin_unlock_bh(&vvs->rx_lock);
1352 if (free_pkt)
1353 kfree_skb(skb);
1354 }
1355
1356 static int
1357 virtio_transport_recv_connected(struct sock *sk,
1358 struct sk_buff *skb)
1359 {
1360 struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1361 struct vsock_sock *vsk = vsock_sk(sk);
1362 int err = 0;
1363
1364 switch (le16_to_cpu(hdr->op)) {
1365 case VIRTIO_VSOCK_OP_RW:
1366 virtio_transport_recv_enqueue(vsk, skb);
1367 vsock_data_ready(sk);
1368 return err;
1369 case VIRTIO_VSOCK_OP_CREDIT_REQUEST:
1370 virtio_transport_send_credit_update(vsk);
1371 break;
1372 case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
1373 sk->sk_write_space(sk);
1374 break;
1375 case VIRTIO_VSOCK_OP_SHUTDOWN:
1376 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SHUTDOWN_RCV)
1377 vsk->peer_shutdown |= RCV_SHUTDOWN;
1378 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SHUTDOWN_SEND)
1379 vsk->peer_shutdown |= SEND_SHUTDOWN;
1380 if (vsk->peer_shutdown == SHUTDOWN_MASK) {
1381 if (vsock_stream_has_data(vsk) <= 0 && !sock_flag(sk, SOCK_DONE)) {
1382 (void)virtio_transport_reset(vsk, NULL);
1383 virtio_transport_do_close(vsk, true);
1384 }
1385 /* Remove this socket anyway because the remote peer sent
1386 * the shutdown. This way a new connection will succeed
1387 * if the remote peer uses the same source port,
1388 * even if the old socket is still unreleased, but now disconnected.
1389 */
1390 vsock_remove_sock(vsk);
1391 }
1392 if (le32_to_cpu(virtio_vsock_hdr(skb)->flags))
1393 sk->sk_state_change(sk);
1394 break;
1395 case VIRTIO_VSOCK_OP_RST:
1396 virtio_transport_do_close(vsk, true);
1397 break;
1398 default:
1399 err = -EINVAL;
1400 break;
1401 }
1402
1403 kfree_skb(skb);
1404 return err;
1405 }
1406
1407 static void
1408 virtio_transport_recv_disconnecting(struct sock *sk,
1409 struct sk_buff *skb)
1410 {
1411 struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1412 struct vsock_sock *vsk = vsock_sk(sk);
1413
1414 if (le16_to_cpu(hdr->op) == VIRTIO_VSOCK_OP_RST)
1415 virtio_transport_do_close(vsk, true);
1416 }
1417
1418 static int
1419 virtio_transport_send_response(struct vsock_sock *vsk,
1420 struct sk_buff *skb)
1421 {
1422 struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1423 struct virtio_vsock_pkt_info info = {
1424 .op = VIRTIO_VSOCK_OP_RESPONSE,
1425 .remote_cid = le64_to_cpu(hdr->src_cid),
1426 .remote_port = le32_to_cpu(hdr->src_port),
1427 .reply = true,
1428 .vsk = vsk,
1429 };
1430
1431 return virtio_transport_send_pkt_info(vsk, &info);
1432 }
1433
1434 static bool virtio_transport_space_update(struct sock *sk,
1435 struct sk_buff *skb)
1436 {
1437 struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1438 struct vsock_sock *vsk = vsock_sk(sk);
1439 struct virtio_vsock_sock *vvs = vsk->trans;
1440 bool space_available;
1441
1442 /* Listener sockets are not associated with any transport, so we are
1443 * not able to take the state to see if there is space available in the
1444 * remote peer, but since they are only used to receive requests, we
1445 * can assume that there is always space available in the other peer.
1446 */
1447 if (!vvs)
1448 return true;
1449
1450 /* buf_alloc and fwd_cnt is always included in the hdr */
1451 spin_lock_bh(&vvs->tx_lock);
1452 vvs->peer_buf_alloc = le32_to_cpu(hdr->buf_alloc);
1453 vvs->peer_fwd_cnt = le32_to_cpu(hdr->fwd_cnt);
1454 space_available = virtio_transport_has_space(vsk);
1455 spin_unlock_bh(&vvs->tx_lock);
1456 return space_available;
1457 }
1458
1459 /* Handle server socket */
1460 static int
1461 virtio_transport_recv_listen(struct sock *sk, struct sk_buff *skb,
1462 struct virtio_transport *t)
1463 {
1464 struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1465 struct vsock_sock *vsk = vsock_sk(sk);
1466 struct vsock_sock *vchild;
1467 struct sock *child;
1468 int ret;
1469
1470 if (le16_to_cpu(hdr->op) != VIRTIO_VSOCK_OP_REQUEST) {
1471 virtio_transport_reset_no_sock(t, skb);
1472 return -EINVAL;
1473 }
1474
1475 if (sk_acceptq_is_full(sk)) {
1476 virtio_transport_reset_no_sock(t, skb);
1477 return -ENOMEM;
1478 }
1479
1480 child = vsock_create_connected(sk);
1481 if (!child) {
1482 virtio_transport_reset_no_sock(t, skb);
1483 return -ENOMEM;
1484 }
1485
1486 sk_acceptq_added(sk);
1487
1488 lock_sock_nested(child, SINGLE_DEPTH_NESTING);
1489
1490 child->sk_state = TCP_ESTABLISHED;
1491
1492 vchild = vsock_sk(child);
1493 vsock_addr_init(&vchild->local_addr, le64_to_cpu(hdr->dst_cid),
1494 le32_to_cpu(hdr->dst_port));
1495 vsock_addr_init(&vchild->remote_addr, le64_to_cpu(hdr->src_cid),
1496 le32_to_cpu(hdr->src_port));
1497
1498 ret = vsock_assign_transport(vchild, vsk);
1499 /* Transport assigned (looking at remote_addr) must be the same
1500 * where we received the request.
1501 */
1502 if (ret || vchild->transport != &t->transport) {
1503 release_sock(child);
1504 virtio_transport_reset_no_sock(t, skb);
1505 sock_put(child);
1506 return ret;
1507 }
1508
1509 if (virtio_transport_space_update(child, skb))
1510 child->sk_write_space(child);
1511
1512 vsock_insert_connected(vchild);
1513 vsock_enqueue_accept(sk, child);
1514 virtio_transport_send_response(vchild, skb);
1515
1516 release_sock(child);
1517
1518 sk->sk_data_ready(sk);
1519 return 0;
1520 }
1521
1522 static bool virtio_transport_valid_type(u16 type)
1523 {
1524 return (type == VIRTIO_VSOCK_TYPE_STREAM) ||
1525 (type == VIRTIO_VSOCK_TYPE_SEQPACKET);
1526 }
1527
1528 /* We are under the virtio-vsock's vsock->rx_lock or vhost-vsock's vq->mutex
1529 * lock.
1530 */
1531 void virtio_transport_recv_pkt(struct virtio_transport *t,
1532 struct sk_buff *skb)
1533 {
1534 struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1535 struct sockaddr_vm src, dst;
1536 struct vsock_sock *vsk;
1537 struct sock *sk;
1538 bool space_available;
1539
1540 vsock_addr_init(&src, le64_to_cpu(hdr->src_cid),
1541 le32_to_cpu(hdr->src_port));
1542 vsock_addr_init(&dst, le64_to_cpu(hdr->dst_cid),
1543 le32_to_cpu(hdr->dst_port));
1544
1545 trace_virtio_transport_recv_pkt(src.svm_cid, src.svm_port,
1546 dst.svm_cid, dst.svm_port,
1547 le32_to_cpu(hdr->len),
1548 le16_to_cpu(hdr->type),
1549 le16_to_cpu(hdr->op),
1550 le32_to_cpu(hdr->flags),
1551 le32_to_cpu(hdr->buf_alloc),
1552 le32_to_cpu(hdr->fwd_cnt));
1553
1554 if (!virtio_transport_valid_type(le16_to_cpu(hdr->type))) {
1555 (void)virtio_transport_reset_no_sock(t, skb);
1556 goto free_pkt;
1557 }
1558
1559 /* The socket must be in connected or bound table
1560 * otherwise send reset back
1561 */
1562 sk = vsock_find_connected_socket(&src, &dst);
1563 if (!sk) {
1564 sk = vsock_find_bound_socket(&dst);
1565 if (!sk) {
1566 (void)virtio_transport_reset_no_sock(t, skb);
1567 goto free_pkt;
1568 }
1569 }
1570
1571 if (virtio_transport_get_type(sk) != le16_to_cpu(hdr->type)) {
1572 (void)virtio_transport_reset_no_sock(t, skb);
1573 sock_put(sk);
1574 goto free_pkt;
1575 }
1576
1577 if (!skb_set_owner_sk_safe(skb, sk)) {
1578 WARN_ONCE(1, "receiving vsock socket has sk_refcnt == 0\n");
1579 goto free_pkt;
1580 }
1581
1582 vsk = vsock_sk(sk);
1583
1584 lock_sock(sk);
1585
1586 /* Check if sk has been closed before lock_sock */
1587 if (sock_flag(sk, SOCK_DONE)) {
1588 (void)virtio_transport_reset_no_sock(t, skb);
1589 release_sock(sk);
1590 sock_put(sk);
1591 goto free_pkt;
1592 }
1593
1594 space_available = virtio_transport_space_update(sk, skb);
1595
1596 /* Update CID in case it has changed after a transport reset event */
1597 if (vsk->local_addr.svm_cid != VMADDR_CID_ANY)
1598 vsk->local_addr.svm_cid = dst.svm_cid;
1599
1600 if (space_available)
1601 sk->sk_write_space(sk);
1602
1603 switch (sk->sk_state) {
1604 case TCP_LISTEN:
1605 virtio_transport_recv_listen(sk, skb, t);
1606 kfree_skb(skb);
1607 break;
1608 case TCP_SYN_SENT:
1609 virtio_transport_recv_connecting(sk, skb);
1610 kfree_skb(skb);
1611 break;
1612 case TCP_ESTABLISHED:
1613 virtio_transport_recv_connected(sk, skb);
1614 break;
1615 case TCP_CLOSING:
1616 virtio_transport_recv_disconnecting(sk, skb);
1617 kfree_skb(skb);
1618 break;
1619 default:
1620 (void)virtio_transport_reset_no_sock(t, skb);
1621 kfree_skb(skb);
1622 break;
1623 }
1624
1625 release_sock(sk);
1626
1627 /* Release refcnt obtained when we fetched this socket out of the
1628 * bound or connected list.
1629 */
1630 sock_put(sk);
1631 return;
1632
1633 free_pkt:
1634 kfree_skb(skb);
1635 }
1636 EXPORT_SYMBOL_GPL(virtio_transport_recv_pkt);
1637
1638 /* Remove skbs found in a queue that have a vsk that matches.
1639 *
1640 * Each skb is freed.
1641 *
1642 * Returns the count of skbs that were reply packets.
1643 */
1644 int virtio_transport_purge_skbs(void *vsk, struct sk_buff_head *queue)
1645 {
1646 struct sk_buff_head freeme;
1647 struct sk_buff *skb, *tmp;
1648 int cnt = 0;
1649
1650 skb_queue_head_init(&freeme);
1651
1652 spin_lock_bh(&queue->lock);
1653 skb_queue_walk_safe(queue, skb, tmp) {
1654 if (vsock_sk(skb->sk) != vsk)
1655 continue;
1656
1657 __skb_unlink(skb, queue);
1658 __skb_queue_tail(&freeme, skb);
1659
1660 if (virtio_vsock_skb_reply(skb))
1661 cnt++;
1662 }
1663 spin_unlock_bh(&queue->lock);
1664
1665 __skb_queue_purge(&freeme);
1666
1667 return cnt;
1668 }
1669 EXPORT_SYMBOL_GPL(virtio_transport_purge_skbs);
1670
1671 int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t recv_actor)
1672 {
1673 struct virtio_vsock_sock *vvs = vsk->trans;
1674 struct sock *sk = sk_vsock(vsk);
1675 struct sk_buff *skb;
1676 int off = 0;
1677 int err;
1678
1679 spin_lock_bh(&vvs->rx_lock);
1680 /* Use __skb_recv_datagram() for race-free handling of the receive. It
1681 * works for types other than dgrams.
1682 */
1683 skb = __skb_recv_datagram(sk, &vvs->rx_queue, MSG_DONTWAIT, &off, &err);
1684 spin_unlock_bh(&vvs->rx_lock);
1685
1686 if (!skb)
1687 return err;
1688
1689 return recv_actor(sk, skb);
1690 }
1691 EXPORT_SYMBOL_GPL(virtio_transport_read_skb);
1692
1693 int virtio_transport_notify_set_rcvlowat(struct vsock_sock *vsk, int val)
1694 {
1695 struct virtio_vsock_sock *vvs = vsk->trans;
1696 bool send_update;
1697
1698 spin_lock_bh(&vvs->rx_lock);
1699
1700 /* If number of available bytes is less than new SO_RCVLOWAT value,
1701 * kick sender to send more data, because sender may sleep in its
1702 * 'send()' syscall waiting for enough space at our side. Also
1703 * don't send credit update when peer already knows actual value -
1704 * such transmission will be useless.
1705 */
1706 send_update = (vvs->rx_bytes < val) &&
1707 (vvs->fwd_cnt != vvs->last_fwd_cnt);
1708
1709 spin_unlock_bh(&vvs->rx_lock);
1710
1711 if (send_update) {
1712 int err;
1713
1714 err = virtio_transport_send_credit_update(vsk);
1715 if (err < 0)
1716 return err;
1717 }
1718
1719 return 0;
1720 }
1721 EXPORT_SYMBOL_GPL(virtio_transport_notify_set_rcvlowat);
1722
1723 MODULE_LICENSE("GPL v2");
1724 MODULE_AUTHOR("Asias He");
1725 MODULE_DESCRIPTION("common code for virtio vsock");
1726
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