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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 <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 	spinlock_t pkt_list_lock; /* protects pkt_list */
19 	struct list_head pkt_list;
20 	struct work_struct pkt_work;
21 };
22 
23 static struct vsock_loopback the_vsock_loopback;
24 
vsock_loopback_get_local_cid(void)25 static u32 vsock_loopback_get_local_cid(void)
26 {
27 	return VMADDR_CID_LOCAL;
28 }
29 
vsock_loopback_send_pkt(struct virtio_vsock_pkt * pkt)30 static int vsock_loopback_send_pkt(struct virtio_vsock_pkt *pkt)
31 {
32 	struct vsock_loopback *vsock = &the_vsock_loopback;
33 	int len = pkt->len;
34 
35 	spin_lock_bh(&vsock->pkt_list_lock);
36 	list_add_tail(&pkt->list, &vsock->pkt_list);
37 	spin_unlock_bh(&vsock->pkt_list_lock);
38 
39 	queue_work(vsock->workqueue, &vsock->pkt_work);
40 
41 	return len;
42 }
43 
vsock_loopback_cancel_pkt(struct vsock_sock * vsk)44 static int vsock_loopback_cancel_pkt(struct vsock_sock *vsk)
45 {
46 	struct vsock_loopback *vsock = &the_vsock_loopback;
47 	struct virtio_vsock_pkt *pkt, *n;
48 	LIST_HEAD(freeme);
49 
50 	spin_lock_bh(&vsock->pkt_list_lock);
51 	list_for_each_entry_safe(pkt, n, &vsock->pkt_list, list) {
52 		if (pkt->vsk != vsk)
53 			continue;
54 		list_move(&pkt->list, &freeme);
55 	}
56 	spin_unlock_bh(&vsock->pkt_list_lock);
57 
58 	list_for_each_entry_safe(pkt, n, &freeme, list) {
59 		list_del(&pkt->list);
60 		virtio_transport_free_pkt(pkt);
61 	}
62 
63 	return 0;
64 }
65 
66 static struct virtio_transport loopback_transport = {
67 	.transport = {
68 		.module                   = THIS_MODULE,
69 
70 		.get_local_cid            = vsock_loopback_get_local_cid,
71 
72 		.init                     = virtio_transport_do_socket_init,
73 		.destruct                 = virtio_transport_destruct,
74 		.release                  = virtio_transport_release,
75 		.connect                  = virtio_transport_connect,
76 		.shutdown                 = virtio_transport_shutdown,
77 		.cancel_pkt               = vsock_loopback_cancel_pkt,
78 
79 		.dgram_bind               = virtio_transport_dgram_bind,
80 		.dgram_dequeue            = virtio_transport_dgram_dequeue,
81 		.dgram_enqueue            = virtio_transport_dgram_enqueue,
82 		.dgram_allow              = virtio_transport_dgram_allow,
83 
84 		.stream_dequeue           = virtio_transport_stream_dequeue,
85 		.stream_enqueue           = virtio_transport_stream_enqueue,
86 		.stream_has_data          = virtio_transport_stream_has_data,
87 		.stream_has_space         = virtio_transport_stream_has_space,
88 		.stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
89 		.stream_is_active         = virtio_transport_stream_is_active,
90 		.stream_allow             = virtio_transport_stream_allow,
91 
92 		.notify_poll_in           = virtio_transport_notify_poll_in,
93 		.notify_poll_out          = virtio_transport_notify_poll_out,
94 		.notify_recv_init         = virtio_transport_notify_recv_init,
95 		.notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
96 		.notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
97 		.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
98 		.notify_send_init         = virtio_transport_notify_send_init,
99 		.notify_send_pre_block    = virtio_transport_notify_send_pre_block,
100 		.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
101 		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
102 		.notify_buffer_size       = virtio_transport_notify_buffer_size,
103 	},
104 
105 	.send_pkt = vsock_loopback_send_pkt,
106 };
107 
vsock_loopback_work(struct work_struct * work)108 static void vsock_loopback_work(struct work_struct *work)
109 {
110 	struct vsock_loopback *vsock =
111 		container_of(work, struct vsock_loopback, pkt_work);
112 	LIST_HEAD(pkts);
113 
114 	spin_lock_bh(&vsock->pkt_list_lock);
115 	list_splice_init(&vsock->pkt_list, &pkts);
116 	spin_unlock_bh(&vsock->pkt_list_lock);
117 
118 	while (!list_empty(&pkts)) {
119 		struct virtio_vsock_pkt *pkt;
120 
121 		pkt = list_first_entry(&pkts, struct virtio_vsock_pkt, list);
122 		list_del_init(&pkt->list);
123 
124 		virtio_transport_deliver_tap_pkt(pkt);
125 		virtio_transport_recv_pkt(&loopback_transport, pkt);
126 	}
127 }
128 
vsock_loopback_init(void)129 static int __init vsock_loopback_init(void)
130 {
131 	struct vsock_loopback *vsock = &the_vsock_loopback;
132 	int ret;
133 
134 	vsock->workqueue = alloc_workqueue("vsock-loopback", 0, 0);
135 	if (!vsock->workqueue)
136 		return -ENOMEM;
137 
138 	spin_lock_init(&vsock->pkt_list_lock);
139 	INIT_LIST_HEAD(&vsock->pkt_list);
140 	INIT_WORK(&vsock->pkt_work, vsock_loopback_work);
141 
142 	ret = vsock_core_register(&loopback_transport.transport,
143 				  VSOCK_TRANSPORT_F_LOCAL);
144 	if (ret)
145 		goto out_wq;
146 
147 	return 0;
148 
149 out_wq:
150 	destroy_workqueue(vsock->workqueue);
151 	return ret;
152 }
153 
vsock_loopback_exit(void)154 static void __exit vsock_loopback_exit(void)
155 {
156 	struct vsock_loopback *vsock = &the_vsock_loopback;
157 	struct virtio_vsock_pkt *pkt;
158 
159 	vsock_core_unregister(&loopback_transport.transport);
160 
161 	flush_work(&vsock->pkt_work);
162 
163 	spin_lock_bh(&vsock->pkt_list_lock);
164 	while (!list_empty(&vsock->pkt_list)) {
165 		pkt = list_first_entry(&vsock->pkt_list,
166 				       struct virtio_vsock_pkt, list);
167 		list_del(&pkt->list);
168 		virtio_transport_free_pkt(pkt);
169 	}
170 	spin_unlock_bh(&vsock->pkt_list_lock);
171 
172 	destroy_workqueue(vsock->workqueue);
173 }
174 
175 module_init(vsock_loopback_init);
176 module_exit(vsock_loopback_exit);
177 MODULE_LICENSE("GPL v2");
178 MODULE_AUTHOR("Stefano Garzarella <sgarzare@redhat.com>");
179 MODULE_DESCRIPTION("loopback transport for vsock");
180 MODULE_ALIAS_NETPROTO(PF_VSOCK);
181