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         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)
  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(u32 remote_cid);
  50
  51 static struct virtio_transport loopback_transport = {
  52         .transport = {
  53                 .module                   = THIS_MODULE,
  54
  55                 .get_local_cid            = vsock_loopback_get_local_cid,
  56
  57                 .init                     = virtio_transport_do_socket_init,
  58                 .destruct                 = virtio_transport_destruct,
  59                 .release                  = virtio_transport_release,
  60                 .connect                  = virtio_transport_connect,
  61                 .shutdown                 = virtio_transport_shutdown,
  62                 .cancel_pkt               = vsock_loopback_cancel_pkt,
  63
  64                 .dgram_bind               = virtio_transport_dgram_bind,
  65                 .dgram_dequeue            = virtio_transport_dgram_dequeue,
  66                 .dgram_enqueue            = virtio_transport_dgram_enqueue,
  67                 .dgram_allow              = virtio_transport_dgram_allow,
  68
  69                 .stream_dequeue           = virtio_transport_stream_dequeue,
  70                 .stream_enqueue           = virtio_transport_stream_enqueue,
  71                 .stream_has_data          = virtio_transport_stream_has_data,
  72                 .stream_has_space         = virtio_transport_stream_has_space,
  73                 .stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
  74                 .stream_is_active         = virtio_transport_stream_is_active,
  75                 .stream_allow             = virtio_transport_stream_allow,
  76
  77                 .seqpacket_dequeue        = virtio_transport_seqpacket_dequeue,
  78                 .seqpacket_enqueue        = virtio_transport_seqpacket_enqueue,
  79                 .seqpacket_allow          = vsock_loopback_seqpacket_allow,
  80                 .seqpacket_has_data       = virtio_transport_seqpacket_has_data,
  81
  82                 .notify_poll_in           = virtio_transport_notify_poll_in,
  83                 .notify_poll_out          = virtio_transport_notify_poll_out,
  84                 .notify_recv_init         = virtio_transport_notify_recv_init,
  85                 .notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
  86                 .notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
  87                 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
  88                 .notify_send_init         = virtio_transport_notify_send_init,
  89                 .notify_send_pre_block    = virtio_transport_notify_send_pre_block,
  90                 .notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
  91                 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
  92                 .notify_buffer_size       = virtio_transport_notify_buffer_size,
  93
  94                 .read_skb = virtio_transport_read_skb,
  95         },
  96
  97         .send_pkt = vsock_loopback_send_pkt,
  98 };
  99
 100 static bool vsock_loopback_seqpacket_allow(u32 remote_cid)
 101 {
 102         return true;
 103 }
 104
 105 static void vsock_loopback_work(struct work_struct *work)
 106 {
 107         struct vsock_loopback *vsock =
 108                 container_of(work, struct vsock_loopback, pkt_work);
 109         struct sk_buff_head pkts;
 110         struct sk_buff *skb;
 111
 112         skb_queue_head_init(&pkts);
 113
 114         spin_lock_bh(&vsock->pkt_queue.lock);
 115         skb_queue_splice_init(&vsock->pkt_queue, &pkts);
 116         spin_unlock_bh(&vsock->pkt_queue.lock);
 117
 118         while ((skb = __skb_dequeue(&pkts))) {
 119                 virtio_transport_deliver_tap_pkt(skb);
 120                 virtio_transport_recv_pkt(&loopback_transport, skb);
 121         }
 122 }
 123
 124 static int __init vsock_loopback_init(void)
 125 {
 126         struct vsock_loopback *vsock = &the_vsock_loopback;
 127         int ret;
 128
 129         vsock->workqueue = alloc_workqueue("vsock-loopback", 0, 0);
 130         if (!vsock->workqueue)
 131                 return -ENOMEM;
 132
 133         skb_queue_head_init(&vsock->pkt_queue);
 134         INIT_WORK(&vsock->pkt_work, vsock_loopback_work);
 135
 136         ret = vsock_core_register(&loopback_transport.transport,
 137                                   VSOCK_TRANSPORT_F_LOCAL);
 138         if (ret)
 139                 goto out_wq;
 140
 141         return 0;
 142
 143 out_wq:
 144         destroy_workqueue(vsock->workqueue);
 145         return ret;
 146 }
 147
 148 static void __exit vsock_loopback_exit(void)
 149 {
 150         struct vsock_loopback *vsock = &the_vsock_loopback;
 151
 152         vsock_core_unregister(&loopback_transport.transport);
 153
 154         flush_work(&vsock->pkt_work);
 155
 156         virtio_vsock_skb_queue_purge(&vsock->pkt_queue);
 157
 158         destroy_workqueue(vsock->workqueue);
 159 }
 160
 161 module_init(vsock_loopback_init);
 162 module_exit(vsock_loopback_exit);
 163 MODULE_LICENSE("GPL v2");
 164 MODULE_AUTHOR("Stefano Garzarella <sgarzare@redhat.com>");
 165 MODULE_DESCRIPTION("loopback transport for vsock");
 166 MODULE_ALIAS_NETPROTO(PF_VSOCK);