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
15 struct vsock_loopback {
16 struct workqueue_struct *workqueue;
17
18 struct sk_buff_head pkt_queue;
19 struct work_struct pkt_work;
20 };
21
22 static struct vsock_loopback the_vsock_loopback;
23
24 static u32 vsock_loopback_get_local_cid(void)
25 {
26 return VMADDR_CID_LOCAL;
27 }
28
29 static 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
40 static 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
49 static bool vsock_loopback_seqpacket_allow(u32 remote_cid);
50 static bool vsock_loopback_msgzerocopy_allow(void)
51 {
52 return true;
53 }
54
55 static 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
107 static bool vsock_loopback_seqpacket_allow(u32 remote_cid)
108 {
109 return true;
110 }
111
112 static 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
131 static 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
150 out_wq:
151 destroy_workqueue(vsock->workqueue);
152 return ret;
153 }
154
155 static 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
168 module_init(vsock_loopback_init);
169 module_exit(vsock_loopback_exit);
170 MODULE_LICENSE("GPL v2");
171 MODULE_AUTHOR("Stefano Garzarella <sgarzare@redhat.com>");
172 MODULE_DESCRIPTION("loopback transport for vsock");
173 MODULE_ALIAS_NETPROTO(PF_VSOCK);
174
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