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(list: &vsock->pkt_queue, skb);
35 queue_work(wq: vsock->workqueue, work: &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, list: &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 .unsent_bytes = virtio_transport_unsent_bytes,
102
103 .read_skb = virtio_transport_read_skb,
104 },
105
106 .send_pkt = vsock_loopback_send_pkt,
107};
108
109static bool vsock_loopback_seqpacket_allow(u32 remote_cid)
110{
111 return true;
112}
113
114static void vsock_loopback_work(struct work_struct *work)
115{
116 struct vsock_loopback *vsock =
117 container_of(work, struct vsock_loopback, pkt_work);
118 struct sk_buff_head pkts;
119 struct sk_buff *skb;
120
121 skb_queue_head_init(list: &pkts);
122
123 spin_lock_bh(lock: &vsock->pkt_queue.lock);
124 skb_queue_splice_init(list: &vsock->pkt_queue, head: &pkts);
125 spin_unlock_bh(lock: &vsock->pkt_queue.lock);
126
127 while ((skb = __skb_dequeue(list: &pkts))) {
128 /* Decrement the bytes_unsent counter without deallocating skb
129 * It is freed by the receiver.
130 */
131 virtio_transport_consume_skb_sent(skb, consume: false);
132 virtio_transport_deliver_tap_pkt(skb);
133 virtio_transport_recv_pkt(t: &loopback_transport, skb);
134 }
135}
136
137static int __init vsock_loopback_init(void)
138{
139 struct vsock_loopback *vsock = &the_vsock_loopback;
140 int ret;
141
142 vsock->workqueue = alloc_workqueue("vsock-loopback", WQ_PERCPU, 0);
143 if (!vsock->workqueue)
144 return -ENOMEM;
145
146 skb_queue_head_init(list: &vsock->pkt_queue);
147 INIT_WORK(&vsock->pkt_work, vsock_loopback_work);
148
149 ret = vsock_core_register(t: &loopback_transport.transport,
150 VSOCK_TRANSPORT_F_LOCAL);
151 if (ret)
152 goto out_wq;
153
154 return 0;
155
156out_wq:
157 destroy_workqueue(wq: vsock->workqueue);
158 return ret;
159}
160
161static void __exit vsock_loopback_exit(void)
162{
163 struct vsock_loopback *vsock = &the_vsock_loopback;
164
165 vsock_core_unregister(t: &loopback_transport.transport);
166
167 flush_work(work: &vsock->pkt_work);
168
169 virtio_vsock_skb_queue_purge(list: &vsock->pkt_queue);
170
171 destroy_workqueue(wq: vsock->workqueue);
172}
173
174module_init(vsock_loopback_init);
175module_exit(vsock_loopback_exit);
176MODULE_LICENSE("GPL v2");
177MODULE_AUTHOR("Stefano Garzarella <sgarzare@redhat.com>");
178MODULE_DESCRIPTION("loopback transport for vsock");
179MODULE_ALIAS_NETPROTO(PF_VSOCK);
180

source code of linux/net/vmw_vsock/vsock_loopback.c