net/vmw_vsock/vsock_loopback.c

   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);