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 static bool vsock_loopback_msgzerocopy_allow(void)
  51 {
  52         return true;
  53 }
  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                 .msgzerocopy_allow        = vsock_loopback_msgzerocopy_allow,
  87
  88                 .notify_poll_in           = virtio_transport_notify_poll_in,
  89                 .notify_poll_out          = virtio_transport_notify_poll_out,
  90                 .notify_recv_init         = virtio_transport_notify_recv_init,
  91                 .notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
  92                 .notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
  93                 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
  94                 .notify_send_init         = virtio_transport_notify_send_init,
  95                 .notify_send_pre_block    = virtio_transport_notify_send_pre_block,
  96                 .notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
  97                 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
  98                 .notify_buffer_size       = virtio_transport_notify_buffer_size,
  99                 .notify_set_rcvlowat      = virtio_transport_notify_set_rcvlowat,
 100
 101                 .unsent_bytes             = virtio_transport_unsent_bytes,
 102
 103                 .read_skb = virtio_transport_read_skb,
 104         },
 105
 106         .send_pkt = vsock_loopback_send_pkt,
 107 };
 108
 109 static bool vsock_loopback_seqpacket_allow(u32 remote_cid)
 110 {
 111         return true;
 112 }
 113
 114 static void vsock_loopback_work(struct work_struct *work)
 115 {
 116         struct vsock_loopback *vsock =
 117                 container_of(work, struct vsock_loopback, pkt_work);
 118         struct sk_buff_head pkts;
 119         struct sk_buff *skb;
 120
 121         skb_queue_head_init(&pkts);
 122
 123         spin_lock_bh(&vsock->pkt_queue.lock);
 124         skb_queue_splice_init(&vsock->pkt_queue, &pkts);
 125         spin_unlock_bh(&vsock->pkt_queue.lock);
 126
 127         while ((skb = __skb_dequeue(&pkts))) {
 128                 /* Decrement the bytes_unsent counter without deallocating skb
 129                  * It is freed by the receiver.
 130                  */
 131                 virtio_transport_consume_skb_sent(skb, false);
 132                 virtio_transport_deliver_tap_pkt(skb);
 133                 virtio_transport_recv_pkt(&loopback_transport, skb);
 134         }
 135 }
 136
 137 static int __init vsock_loopback_init(void)
 138 {
 139         struct vsock_loopback *vsock = &the_vsock_loopback;
 140         int ret;
 141
 142         vsock->workqueue = alloc_workqueue("vsock-loopback", 0, 0);
 143         if (!vsock->workqueue)
 144                 return -ENOMEM;
 145
 146         skb_queue_head_init(&vsock->pkt_queue);
 147         INIT_WORK(&vsock->pkt_work, vsock_loopback_work);
 148
 149         ret = vsock_core_register(&loopback_transport.transport,
 150                                   VSOCK_TRANSPORT_F_LOCAL);
 151         if (ret)
 152                 goto out_wq;
 153
 154         return 0;
 155
 156 out_wq:
 157         destroy_workqueue(vsock->workqueue);
 158         return ret;
 159 }
 160
 161 static void __exit vsock_loopback_exit(void)
 162 {
 163         struct vsock_loopback *vsock = &the_vsock_loopback;
 164
 165         vsock_core_unregister(&loopback_transport.transport);
 166
 167         flush_work(&vsock->pkt_work);
 168
 169         virtio_vsock_skb_queue_purge(&vsock->pkt_queue);
 170
 171         destroy_workqueue(vsock->workqueue);
 172 }
 173
 174 module_init(vsock_loopback_init);
 175 module_exit(vsock_loopback_exit);
 176 MODULE_LICENSE("GPL v2");
 177 MODULE_AUTHOR("Stefano Garzarella <sgarzare@redhat.com>");
 178 MODULE_DESCRIPTION("loopback transport for vsock");
 179 MODULE_ALIAS_NETPROTO(PF_VSOCK);