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 25 static u32 vsock_loopback_get_local_cid(void) 26 { 27 return VMADDR_CID_LOCAL; 28 } 29 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 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 }; 107 108 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 } 128 129 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 } 153 154 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