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 
51 static 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 
94 		.read_skb = virtio_transport_read_skb,
95 	},
96 
97 	.send_pkt = vsock_loopback_send_pkt,
98 };
99 
100 static bool vsock_loopback_seqpacket_allow(u32 remote_cid)
101 {
102 	return true;
103 }
104 
105 static void vsock_loopback_work(struct work_struct *work)
106 {
107 	struct vsock_loopback *vsock =
108 		container_of(work, struct vsock_loopback, pkt_work);
109 	struct sk_buff_head pkts;
110 	struct sk_buff *skb;
111 
112 	skb_queue_head_init(&pkts);
113 
114 	spin_lock_bh(&vsock->pkt_queue.lock);
115 	skb_queue_splice_init(&vsock->pkt_queue, &pkts);
116 	spin_unlock_bh(&vsock->pkt_queue.lock);
117 
118 	while ((skb = __skb_dequeue(&pkts))) {
119 		virtio_transport_deliver_tap_pkt(skb);
120 		virtio_transport_recv_pkt(&loopback_transport, skb);
121 	}
122 }
123 
124 static int __init vsock_loopback_init(void)
125 {
126 	struct vsock_loopback *vsock = &the_vsock_loopback;
127 	int ret;
128 
129 	vsock->workqueue = alloc_workqueue("vsock-loopback", 0, 0);
130 	if (!vsock->workqueue)
131 		return -ENOMEM;
132 
133 	skb_queue_head_init(&vsock->pkt_queue);
134 	INIT_WORK(&vsock->pkt_work, vsock_loopback_work);
135 
136 	ret = vsock_core_register(&loopback_transport.transport,
137 				  VSOCK_TRANSPORT_F_LOCAL);
138 	if (ret)
139 		goto out_wq;
140 
141 	return 0;
142 
143 out_wq:
144 	destroy_workqueue(vsock->workqueue);
145 	return ret;
146 }
147 
148 static void __exit vsock_loopback_exit(void)
149 {
150 	struct vsock_loopback *vsock = &the_vsock_loopback;
151 
152 	vsock_core_unregister(&loopback_transport.transport);
153 
154 	flush_work(&vsock->pkt_work);
155 
156 	virtio_vsock_skb_queue_purge(&vsock->pkt_queue);
157 
158 	destroy_workqueue(vsock->workqueue);
159 }
160 
161 module_init(vsock_loopback_init);
162 module_exit(vsock_loopback_exit);
163 MODULE_LICENSE("GPL v2");
164 MODULE_AUTHOR("Stefano Garzarella <sgarzare@redhat.com>");
165 MODULE_DESCRIPTION("loopback transport for vsock");
166 MODULE_ALIAS_NETPROTO(PF_VSOCK);
167