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);
50static bool vsock_loopback_msgzerocopy_allow(void)
51{
52	return true;
53}
54
55static struct virtio_transport loopback_transport = {
56	.transport = {
57		.module                   = THIS_MODULE,
58
59		.get_local_cid            = vsock_loopback_get_local_cid,
60
61		.init                     = virtio_transport_do_socket_init,
62		.destruct                 = virtio_transport_destruct,
63		.release                  = virtio_transport_release,
64		.connect                  = virtio_transport_connect,
65		.shutdown                 = virtio_transport_shutdown,
66		.cancel_pkt               = vsock_loopback_cancel_pkt,
67
68		.dgram_bind               = virtio_transport_dgram_bind,
69		.dgram_dequeue            = virtio_transport_dgram_dequeue,
70		.dgram_enqueue            = virtio_transport_dgram_enqueue,
71		.dgram_allow              = virtio_transport_dgram_allow,
72
73		.stream_dequeue           = virtio_transport_stream_dequeue,
74		.stream_enqueue           = virtio_transport_stream_enqueue,
75		.stream_has_data          = virtio_transport_stream_has_data,
76		.stream_has_space         = virtio_transport_stream_has_space,
77		.stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
78		.stream_is_active         = virtio_transport_stream_is_active,
79		.stream_allow             = virtio_transport_stream_allow,
80
81		.seqpacket_dequeue        = virtio_transport_seqpacket_dequeue,
82		.seqpacket_enqueue        = virtio_transport_seqpacket_enqueue,
83		.seqpacket_allow          = vsock_loopback_seqpacket_allow,
84		.seqpacket_has_data       = virtio_transport_seqpacket_has_data,
85
86		.msgzerocopy_allow        = vsock_loopback_msgzerocopy_allow,
87
88		.notify_poll_in           = virtio_transport_notify_poll_in,
89		.notify_poll_out          = virtio_transport_notify_poll_out,
90		.notify_recv_init         = virtio_transport_notify_recv_init,
91		.notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
92		.notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
93		.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
94		.notify_send_init         = virtio_transport_notify_send_init,
95		.notify_send_pre_block    = virtio_transport_notify_send_pre_block,
96		.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
97		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
98		.notify_buffer_size       = virtio_transport_notify_buffer_size,
99		.notify_set_rcvlowat      = virtio_transport_notify_set_rcvlowat,
100
101		.read_skb = virtio_transport_read_skb,
102	},
103
104	.send_pkt = vsock_loopback_send_pkt,
105};
106
107static bool vsock_loopback_seqpacket_allow(u32 remote_cid)
108{
109	return true;
110}
111
112static void vsock_loopback_work(struct work_struct *work)
113{
114	struct vsock_loopback *vsock =
115		container_of(work, struct vsock_loopback, pkt_work);
116	struct sk_buff_head pkts;
117	struct sk_buff *skb;
118
119	skb_queue_head_init(&pkts);
120
121	spin_lock_bh(&vsock->pkt_queue.lock);
122	skb_queue_splice_init(&vsock->pkt_queue, &pkts);
123	spin_unlock_bh(&vsock->pkt_queue.lock);
124
125	while ((skb = __skb_dequeue(&pkts))) {
126		virtio_transport_deliver_tap_pkt(skb);
127		virtio_transport_recv_pkt(&loopback_transport, skb);
128	}
129}
130
131static int __init vsock_loopback_init(void)
132{
133	struct vsock_loopback *vsock = &the_vsock_loopback;
134	int ret;
135
136	vsock->workqueue = alloc_workqueue("vsock-loopback", 0, 0);
137	if (!vsock->workqueue)
138		return -ENOMEM;
139
140	skb_queue_head_init(&vsock->pkt_queue);
141	INIT_WORK(&vsock->pkt_work, vsock_loopback_work);
142
143	ret = vsock_core_register(&loopback_transport.transport,
144				  VSOCK_TRANSPORT_F_LOCAL);
145	if (ret)
146		goto out_wq;
147
148	return 0;
149
150out_wq:
151	destroy_workqueue(vsock->workqueue);
152	return ret;
153}
154
155static void __exit vsock_loopback_exit(void)
156{
157	struct vsock_loopback *vsock = &the_vsock_loopback;
158
159	vsock_core_unregister(&loopback_transport.transport);
160
161	flush_work(&vsock->pkt_work);
162
163	virtio_vsock_skb_queue_purge(&vsock->pkt_queue);
164
165	destroy_workqueue(vsock->workqueue);
166}
167
168module_init(vsock_loopback_init);
169module_exit(vsock_loopback_exit);
170MODULE_LICENSE("GPL v2");
171MODULE_AUTHOR("Stefano Garzarella <sgarzare@redhat.com>");
172MODULE_DESCRIPTION("loopback transport for vsock");
173MODULE_ALIAS_NETPROTO(PF_VSOCK);
174