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, struct net *net) 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(struct vsock_sock *vsk, 50 u32 remote_cid); 51 52 static bool vsock_loopback_stream_allow(struct vsock_sock *vsk, u32 cid, 53 u32 port) 54 { 55 return true; 56 } 57 58 static bool vsock_loopback_msgzerocopy_allow(void) 59 { 60 return true; 61 } 62 63 static struct virtio_transport loopback_transport = { 64 .transport = { 65 .module = THIS_MODULE, 66 67 .get_local_cid = vsock_loopback_get_local_cid, 68 69 .init = virtio_transport_do_socket_init, 70 .destruct = virtio_transport_destruct, 71 .release = virtio_transport_release, 72 .connect = virtio_transport_connect, 73 .shutdown = virtio_transport_shutdown, 74 .cancel_pkt = vsock_loopback_cancel_pkt, 75 76 .dgram_bind = virtio_transport_dgram_bind, 77 .dgram_dequeue = virtio_transport_dgram_dequeue, 78 .dgram_enqueue = virtio_transport_dgram_enqueue, 79 .dgram_allow = virtio_transport_dgram_allow, 80 81 .stream_dequeue = virtio_transport_stream_dequeue, 82 .stream_enqueue = virtio_transport_stream_enqueue, 83 .stream_has_data = virtio_transport_stream_has_data, 84 .stream_has_space = virtio_transport_stream_has_space, 85 .stream_rcvhiwat = virtio_transport_stream_rcvhiwat, 86 .stream_is_active = virtio_transport_stream_is_active, 87 .stream_allow = vsock_loopback_stream_allow, 88 89 .seqpacket_dequeue = virtio_transport_seqpacket_dequeue, 90 .seqpacket_enqueue = virtio_transport_seqpacket_enqueue, 91 .seqpacket_allow = vsock_loopback_seqpacket_allow, 92 .seqpacket_has_data = virtio_transport_seqpacket_has_data, 93 94 .msgzerocopy_allow = vsock_loopback_msgzerocopy_allow, 95 96 .notify_poll_in = virtio_transport_notify_poll_in, 97 .notify_poll_out = virtio_transport_notify_poll_out, 98 .notify_recv_init = virtio_transport_notify_recv_init, 99 .notify_recv_pre_block = virtio_transport_notify_recv_pre_block, 100 .notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue, 101 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue, 102 .notify_send_init = virtio_transport_notify_send_init, 103 .notify_send_pre_block = virtio_transport_notify_send_pre_block, 104 .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue, 105 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue, 106 .notify_buffer_size = virtio_transport_notify_buffer_size, 107 .notify_set_rcvlowat = virtio_transport_notify_set_rcvlowat, 108 109 .unsent_bytes = virtio_transport_unsent_bytes, 110 111 .read_skb = virtio_transport_read_skb, 112 }, 113 114 .send_pkt = vsock_loopback_send_pkt, 115 }; 116 117 static bool 118 vsock_loopback_seqpacket_allow(struct vsock_sock *vsk, u32 remote_cid) 119 { 120 return vsock_net_mode_global(vsk); 121 } 122 123 static void vsock_loopback_work(struct work_struct *work) 124 { 125 struct vsock_loopback *vsock = 126 container_of(work, struct vsock_loopback, pkt_work); 127 struct sk_buff_head pkts; 128 struct sk_buff *skb; 129 130 skb_queue_head_init(&pkts); 131 132 spin_lock_bh(&vsock->pkt_queue.lock); 133 skb_queue_splice_init(&vsock->pkt_queue, &pkts); 134 spin_unlock_bh(&vsock->pkt_queue.lock); 135 136 while ((skb = __skb_dequeue(&pkts))) { 137 /* Decrement the bytes_unsent counter without deallocating skb 138 * It is freed by the receiver. 139 */ 140 virtio_transport_consume_skb_sent(skb, false); 141 virtio_transport_deliver_tap_pkt(skb); 142 virtio_transport_recv_pkt(&loopback_transport, skb, 143 sock_net(skb->sk)); 144 } 145 } 146 147 static int __init vsock_loopback_init(void) 148 { 149 struct vsock_loopback *vsock = &the_vsock_loopback; 150 int ret; 151 152 vsock->workqueue = alloc_workqueue("vsock-loopback", WQ_PERCPU, 0); 153 if (!vsock->workqueue) 154 return -ENOMEM; 155 156 skb_queue_head_init(&vsock->pkt_queue); 157 INIT_WORK(&vsock->pkt_work, vsock_loopback_work); 158 159 ret = vsock_core_register(&loopback_transport.transport, 160 VSOCK_TRANSPORT_F_LOCAL); 161 if (ret) 162 goto out_wq; 163 164 return 0; 165 166 out_wq: 167 destroy_workqueue(vsock->workqueue); 168 return ret; 169 } 170 171 static void __exit vsock_loopback_exit(void) 172 { 173 struct vsock_loopback *vsock = &the_vsock_loopback; 174 175 vsock_core_unregister(&loopback_transport.transport); 176 177 flush_work(&vsock->pkt_work); 178 179 virtio_vsock_skb_queue_purge(&vsock->pkt_queue); 180 181 destroy_workqueue(vsock->workqueue); 182 } 183 184 module_init(vsock_loopback_init); 185 module_exit(vsock_loopback_exit); 186 MODULE_LICENSE("GPL v2"); 187 MODULE_AUTHOR("Stefano Garzarella <sgarzare@redhat.com>"); 188 MODULE_DESCRIPTION("loopback transport for vsock"); 189 MODULE_ALIAS_NETPROTO(PF_VSOCK); 190