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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 <[email protected]>
6 * Stefan Hajnoczi <[email protected]>
7 * Stefano Garzarella <[email protected]>
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, struct net *net)
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(struct vsock_sock *vsk,
50 u32 remote_cid);
51
52static bool vsock_loopback_stream_allow(struct vsock_sock *vsk, u32 cid,
53 u32 port)
54{
55 return true;
56}
57
58static bool vsock_loopback_msgzerocopy_allow(void)
59{
60 return true;
61}
62
63static struct virtio_transport loopback_transport = {
64 .transport = {
65 .module = THIS_MODULE,
66
67 .get_local_cid = vsock_loopback_get_local_cid,
68
69 .init = virtio_transport_do_socket_init,
70 .destruct = virtio_transport_destruct,
71 .release = virtio_transport_release,
72 .connect = virtio_transport_connect,
73 .shutdown = virtio_transport_shutdown,
74 .cancel_pkt = vsock_loopback_cancel_pkt,
75
76 .dgram_bind = virtio_transport_dgram_bind,
77 .dgram_dequeue = virtio_transport_dgram_dequeue,
78 .dgram_enqueue = virtio_transport_dgram_enqueue,
79 .dgram_allow = virtio_transport_dgram_allow,
80
81 .stream_dequeue = virtio_transport_stream_dequeue,
82 .stream_enqueue = virtio_transport_stream_enqueue,
83 .stream_has_data = virtio_transport_stream_has_data,
84 .stream_has_space = virtio_transport_stream_has_space,
85 .stream_rcvhiwat = virtio_transport_stream_rcvhiwat,
86 .stream_is_active = virtio_transport_stream_is_active,
87 .stream_allow = vsock_loopback_stream_allow,
88
89 .seqpacket_dequeue = virtio_transport_seqpacket_dequeue,
90 .seqpacket_enqueue = virtio_transport_seqpacket_enqueue,
91 .seqpacket_allow = vsock_loopback_seqpacket_allow,
92 .seqpacket_has_data = virtio_transport_seqpacket_has_data,
93
94 .msgzerocopy_allow = vsock_loopback_msgzerocopy_allow,
95
96 .notify_poll_in = virtio_transport_notify_poll_in,
97 .notify_poll_out = virtio_transport_notify_poll_out,
98 .notify_recv_init = virtio_transport_notify_recv_init,
99 .notify_recv_pre_block = virtio_transport_notify_recv_pre_block,
100 .notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue,
101 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
102 .notify_send_init = virtio_transport_notify_send_init,
103 .notify_send_pre_block = virtio_transport_notify_send_pre_block,
104 .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue,
105 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
106 .notify_buffer_size = virtio_transport_notify_buffer_size,
107 .notify_set_rcvlowat = virtio_transport_notify_set_rcvlowat,
108
109 .unsent_bytes = virtio_transport_unsent_bytes,
110
111 .read_skb = virtio_transport_read_skb,
112 },
113
114 .send_pkt = vsock_loopback_send_pkt,
115};
116
117static bool
118vsock_loopback_seqpacket_allow(struct vsock_sock *vsk, u32 remote_cid)
119{
120 return vsock_net_mode_global(vsk);
121}
122
123static void vsock_loopback_work(struct work_struct *work)
124{
125 struct vsock_loopback *vsock =
126 container_of(work, struct vsock_loopback, pkt_work);
127 struct sk_buff_head pkts;
128 struct sk_buff *skb;
129
130 skb_queue_head_init(&pkts);
131
132 spin_lock_bh(&vsock->pkt_queue.lock);
133 skb_queue_splice_init(&vsock->pkt_queue, &pkts);
134 spin_unlock_bh(&vsock->pkt_queue.lock);
135
136 while ((skb = __skb_dequeue(&pkts))) {
137 /* Decrement the bytes_unsent counter without deallocating skb
138 * It is freed by the receiver.
139 */
140 virtio_transport_consume_skb_sent(skb, false);
141 virtio_transport_deliver_tap_pkt(skb);
142 virtio_transport_recv_pkt(&loopback_transport, skb,
143 sock_net(skb->sk));
144 }
145}
146
147static int __init vsock_loopback_init(void)
148{
149 struct vsock_loopback *vsock = &the_vsock_loopback;
150 int ret;
151
152 vsock->workqueue = alloc_workqueue("vsock-loopback", WQ_PERCPU, 0);
153 if (!vsock->workqueue)
154 return -ENOMEM;
155
156 skb_queue_head_init(&vsock->pkt_queue);
157 INIT_WORK(&vsock->pkt_work, vsock_loopback_work);
158
159 ret = vsock_core_register(&loopback_transport.transport,
160 VSOCK_TRANSPORT_F_LOCAL);
161 if (ret)
162 goto out_wq;
163
164 return 0;
165
166out_wq:
167 destroy_workqueue(vsock->workqueue);
168 return ret;
169}
170
171static void __exit vsock_loopback_exit(void)
172{
173 struct vsock_loopback *vsock = &the_vsock_loopback;
174
175 vsock_core_unregister(&loopback_transport.transport);
176
177 flush_work(&vsock->pkt_work);
178
179 virtio_vsock_skb_queue_purge(&vsock->pkt_queue);
180
181 destroy_workqueue(vsock->workqueue);
182}
183
184module_init(vsock_loopback_init);
185module_exit(vsock_loopback_exit);
186MODULE_LICENSE("GPL v2");
187MODULE_AUTHOR("Stefano Garzarella <[email protected]>");
188MODULE_DESCRIPTION("loopback transport for vsock");
189MODULE_ALIAS_NETPROTO(PF_VSOCK);