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 sk_buff_head pkt_queue;
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 sk_buff * skb)30 static int vsock_loopback_send_pkt(struct sk_buff *skb)
31 {
32 struct vsock_loopback *vsock = &the_vsock_loopback;
33 int len = skb->len;
34
35 spin_lock_bh(&vsock->pkt_list_lock);
36 skb_queue_tail(&vsock->pkt_queue, skb);
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
48 virtio_transport_purge_skbs(vsk, &vsock->pkt_queue);
49
50 return 0;
51 }
52
53 static bool vsock_loopback_seqpacket_allow(u32 remote_cid);
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 .notify_poll_in = virtio_transport_notify_poll_in,
87 .notify_poll_out = virtio_transport_notify_poll_out,
88 .notify_recv_init = virtio_transport_notify_recv_init,
89 .notify_recv_pre_block = virtio_transport_notify_recv_pre_block,
90 .notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue,
91 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
92 .notify_send_init = virtio_transport_notify_send_init,
93 .notify_send_pre_block = virtio_transport_notify_send_pre_block,
94 .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue,
95 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
96 .notify_buffer_size = virtio_transport_notify_buffer_size,
97 },
98
99 .send_pkt = vsock_loopback_send_pkt,
100 };
101
vsock_loopback_seqpacket_allow(u32 remote_cid)102 static bool vsock_loopback_seqpacket_allow(u32 remote_cid)
103 {
104 return true;
105 }
106
vsock_loopback_work(struct work_struct * work)107 static void vsock_loopback_work(struct work_struct *work)
108 {
109 struct vsock_loopback *vsock =
110 container_of(work, struct vsock_loopback, pkt_work);
111 struct sk_buff_head pkts;
112 struct sk_buff *skb;
113
114 skb_queue_head_init(&pkts);
115
116 spin_lock_bh(&vsock->pkt_list_lock);
117 skb_queue_splice_init(&vsock->pkt_queue, &pkts);
118 spin_unlock_bh(&vsock->pkt_list_lock);
119
120 while ((skb = __skb_dequeue(&pkts))) {
121 virtio_transport_deliver_tap_pkt(skb);
122 virtio_transport_recv_pkt(&loopback_transport, skb);
123 }
124 }
125
vsock_loopback_init(void)126 static int __init vsock_loopback_init(void)
127 {
128 struct vsock_loopback *vsock = &the_vsock_loopback;
129 int ret;
130
131 vsock->workqueue = alloc_workqueue("vsock-loopback", 0, 0);
132 if (!vsock->workqueue)
133 return -ENOMEM;
134
135 spin_lock_init(&vsock->pkt_list_lock);
136 skb_queue_head_init(&vsock->pkt_queue);
137 INIT_WORK(&vsock->pkt_work, vsock_loopback_work);
138
139 ret = vsock_core_register(&loopback_transport.transport,
140 VSOCK_TRANSPORT_F_LOCAL);
141 if (ret)
142 goto out_wq;
143
144 return 0;
145
146 out_wq:
147 destroy_workqueue(vsock->workqueue);
148 return ret;
149 }
150
vsock_loopback_exit(void)151 static void __exit vsock_loopback_exit(void)
152 {
153 struct vsock_loopback *vsock = &the_vsock_loopback;
154
155 vsock_core_unregister(&loopback_transport.transport);
156
157 flush_work(&vsock->pkt_work);
158
159 spin_lock_bh(&vsock->pkt_list_lock);
160 virtio_vsock_skb_queue_purge(&vsock->pkt_queue);
161 spin_unlock_bh(&vsock->pkt_list_lock);
162
163 destroy_workqueue(vsock->workqueue);
164 }
165
166 module_init(vsock_loopback_init);
167 module_exit(vsock_loopback_exit);
168 MODULE_LICENSE("GPL v2");
169 MODULE_AUTHOR("Stefano Garzarella <sgarzare@redhat.com>");
170 MODULE_DESCRIPTION("loopback transport for vsock");
171 MODULE_ALIAS_NETPROTO(PF_VSOCK);
172