1// SPDX-License-Identifier: GPL-2.0-only
2/* loopback transport for vsock using virtio_transport_common APIs
3 *
4 * Copyright (C) 2013-2019 Red Hat, Inc.
5 * Authors: Asias He <asias@redhat.com>
6 *          Stefan Hajnoczi <stefanha@redhat.com>
7 *          Stefano Garzarella <sgarzare@redhat.com>
8 *
9 */
10#include <linux/spinlock.h>
11#include <linux/module.h>
12#include <linux/list.h>
13#include <linux/virtio_vsock.h>
14
15struct vsock_loopback {
16	struct workqueue_struct *workqueue;
17
18	struct sk_buff_head pkt_queue;
19	struct work_struct pkt_work;
20};
21
22static struct vsock_loopback the_vsock_loopback;
23
24static u32 vsock_loopback_get_local_cid(void)
25{
26	return VMADDR_CID_LOCAL;
27}
28
29static int vsock_loopback_send_pkt(struct sk_buff *skb)
30{
31	struct vsock_loopback *vsock = &the_vsock_loopback;
32	int len = skb->len;
33
34	virtio_vsock_skb_queue_tail(&vsock->pkt_queue, skb);
35	queue_work(vsock->workqueue, &vsock->pkt_work);
36
37	return len;
38}
39
40static int vsock_loopback_cancel_pkt(struct vsock_sock *vsk)
41{
42	struct vsock_loopback *vsock = &the_vsock_loopback;
43
44	virtio_transport_purge_skbs(vsk, &vsock->pkt_queue);
45
46	return 0;
47}
48
49static bool vsock_loopback_seqpacket_allow(u32 remote_cid);
50
51static struct virtio_transport loopback_transport = {
52	.transport = {
53		.module                   = THIS_MODULE,
54
55		.get_local_cid            = vsock_loopback_get_local_cid,
56
57		.init                     = virtio_transport_do_socket_init,
58		.destruct                 = virtio_transport_destruct,
59		.release                  = virtio_transport_release,
60		.connect                  = virtio_transport_connect,
61		.shutdown                 = virtio_transport_shutdown,
62		.cancel_pkt               = vsock_loopback_cancel_pkt,
63
64		.dgram_bind               = virtio_transport_dgram_bind,
65		.dgram_dequeue            = virtio_transport_dgram_dequeue,
66		.dgram_enqueue            = virtio_transport_dgram_enqueue,
67		.dgram_allow              = virtio_transport_dgram_allow,
68
69		.stream_dequeue           = virtio_transport_stream_dequeue,
70		.stream_enqueue           = virtio_transport_stream_enqueue,
71		.stream_has_data          = virtio_transport_stream_has_data,
72		.stream_has_space         = virtio_transport_stream_has_space,
73		.stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
74		.stream_is_active         = virtio_transport_stream_is_active,
75		.stream_allow             = virtio_transport_stream_allow,
76
77		.seqpacket_dequeue        = virtio_transport_seqpacket_dequeue,
78		.seqpacket_enqueue        = virtio_transport_seqpacket_enqueue,
79		.seqpacket_allow          = vsock_loopback_seqpacket_allow,
80		.seqpacket_has_data       = virtio_transport_seqpacket_has_data,
81
82		.notify_poll_in           = virtio_transport_notify_poll_in,
83		.notify_poll_out          = virtio_transport_notify_poll_out,
84		.notify_recv_init         = virtio_transport_notify_recv_init,
85		.notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
86		.notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
87		.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
88		.notify_send_init         = virtio_transport_notify_send_init,
89		.notify_send_pre_block    = virtio_transport_notify_send_pre_block,
90		.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
91		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
92		.notify_buffer_size       = virtio_transport_notify_buffer_size,
93		.notify_set_rcvlowat      = virtio_transport_notify_set_rcvlowat,
94
95		.read_skb = virtio_transport_read_skb,
96	},
97
98	.send_pkt = vsock_loopback_send_pkt,
99};
100
101static bool vsock_loopback_seqpacket_allow(u32 remote_cid)
102{
103	return true;
104}
105
106static void vsock_loopback_work(struct work_struct *work)
107{
108	struct vsock_loopback *vsock =
109		container_of(work, struct vsock_loopback, pkt_work);
110	struct sk_buff_head pkts;
111	struct sk_buff *skb;
112
113	skb_queue_head_init(&pkts);
114
115	spin_lock_bh(&vsock->pkt_queue.lock);
116	skb_queue_splice_init(&vsock->pkt_queue, &pkts);
117	spin_unlock_bh(&vsock->pkt_queue.lock);
118
119	while ((skb = __skb_dequeue(&pkts))) {
120		virtio_transport_deliver_tap_pkt(skb);
121		virtio_transport_recv_pkt(&loopback_transport, skb);
122	}
123}
124
125static int __init vsock_loopback_init(void)
126{
127	struct vsock_loopback *vsock = &the_vsock_loopback;
128	int ret;
129
130	vsock->workqueue = alloc_workqueue("vsock-loopback", 0, 0);
131	if (!vsock->workqueue)
132		return -ENOMEM;
133
134	skb_queue_head_init(&vsock->pkt_queue);
135	INIT_WORK(&vsock->pkt_work, vsock_loopback_work);
136
137	ret = vsock_core_register(&loopback_transport.transport,
138				  VSOCK_TRANSPORT_F_LOCAL);
139	if (ret)
140		goto out_wq;
141
142	return 0;
143
144out_wq:
145	destroy_workqueue(vsock->workqueue);
146	return ret;
147}
148
149static void __exit vsock_loopback_exit(void)
150{
151	struct vsock_loopback *vsock = &the_vsock_loopback;
152
153	vsock_core_unregister(&loopback_transport.transport);
154
155	flush_work(&vsock->pkt_work);
156
157	virtio_vsock_skb_queue_purge(&vsock->pkt_queue);
158
159	destroy_workqueue(vsock->workqueue);
160}
161
162module_init(vsock_loopback_init);
163module_exit(vsock_loopback_exit);
164MODULE_LICENSE("GPL v2");
165MODULE_AUTHOR("Stefano Garzarella <sgarzare@redhat.com>");
166MODULE_DESCRIPTION("loopback transport for vsock");
167MODULE_ALIAS_NETPROTO(PF_VSOCK);
168