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 bool vsock_loopback_seqpacket_allow(u32 remote_cid);
  67
  68 static struct virtio_transport loopback_transport = {
  69         .transport = {
  70                 .module                   = THIS_MODULE,
  71
  72                 .get_local_cid            = vsock_loopback_get_local_cid,
  73
  74                 .init                     = virtio_transport_do_socket_init,
  75                 .destruct                 = virtio_transport_destruct,
  76                 .release                  = virtio_transport_release,
  77                 .connect                  = virtio_transport_connect,
  78                 .shutdown                 = virtio_transport_shutdown,
  79                 .cancel_pkt               = vsock_loopback_cancel_pkt,
  80
  81                 .dgram_bind               = virtio_transport_dgram_bind,
  82                 .dgram_dequeue            = virtio_transport_dgram_dequeue,
  83                 .dgram_enqueue            = virtio_transport_dgram_enqueue,
  84                 .dgram_allow              = virtio_transport_dgram_allow,
  85
  86                 .stream_dequeue           = virtio_transport_stream_dequeue,
  87                 .stream_enqueue           = virtio_transport_stream_enqueue,
  88                 .stream_has_data          = virtio_transport_stream_has_data,
  89                 .stream_has_space         = virtio_transport_stream_has_space,
  90                 .stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
  91                 .stream_is_active         = virtio_transport_stream_is_active,
  92                 .stream_allow             = virtio_transport_stream_allow,
  93
  94                 .seqpacket_dequeue        = virtio_transport_seqpacket_dequeue,
  95                 .seqpacket_enqueue        = virtio_transport_seqpacket_enqueue,
  96                 .seqpacket_allow          = vsock_loopback_seqpacket_allow,
  97                 .seqpacket_has_data       = virtio_transport_seqpacket_has_data,
  98
  99                 .notify_poll_in           = virtio_transport_notify_poll_in,
 100                 .notify_poll_out          = virtio_transport_notify_poll_out,
 101                 .notify_recv_init         = virtio_transport_notify_recv_init,
 102                 .notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
 103                 .notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
 104                 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
 105                 .notify_send_init         = virtio_transport_notify_send_init,
 106                 .notify_send_pre_block    = virtio_transport_notify_send_pre_block,
 107                 .notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
 108                 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
 109                 .notify_buffer_size       = virtio_transport_notify_buffer_size,
 110         },
 111
 112         .send_pkt = vsock_loopback_send_pkt,
 113 };
 114
 115 static bool vsock_loopback_seqpacket_allow(u32 remote_cid)
 116 {
 117         return true;
 118 }
 119
 120 static void vsock_loopback_work(struct work_struct *work)
 121 {
 122         struct vsock_loopback *vsock =
 123                 container_of(work, struct vsock_loopback, pkt_work);
 124         LIST_HEAD(pkts);
 125
 126         spin_lock_bh(&vsock->pkt_list_lock);
 127         list_splice_init(&vsock->pkt_list, &pkts);
 128         spin_unlock_bh(&vsock->pkt_list_lock);
 129
 130         while (!list_empty(&pkts)) {
 131                 struct virtio_vsock_pkt *pkt;
 132
 133                 pkt = list_first_entry(&pkts, struct virtio_vsock_pkt, list);
 134                 list_del_init(&pkt->list);
 135
 136                 virtio_transport_deliver_tap_pkt(pkt);
 137                 virtio_transport_recv_pkt(&loopback_transport, pkt);
 138         }
 139 }
 140
 141 static int __init vsock_loopback_init(void)
 142 {
 143         struct vsock_loopback *vsock = &the_vsock_loopback;
 144         int ret;
 145
 146         vsock->workqueue = alloc_workqueue("vsock-loopback", 0, 0);
 147         if (!vsock->workqueue)
 148                 return -ENOMEM;
 149
 150         spin_lock_init(&vsock->pkt_list_lock);
 151         INIT_LIST_HEAD(&vsock->pkt_list);
 152         INIT_WORK(&vsock->pkt_work, vsock_loopback_work);
 153
 154         ret = vsock_core_register(&loopback_transport.transport,
 155                                   VSOCK_TRANSPORT_F_LOCAL);
 156         if (ret)
 157                 goto out_wq;
 158
 159         return 0;
 160
 161 out_wq:
 162         destroy_workqueue(vsock->workqueue);
 163         return ret;
 164 }
 165
 166 static void __exit vsock_loopback_exit(void)
 167 {
 168         struct vsock_loopback *vsock = &the_vsock_loopback;
 169         struct virtio_vsock_pkt *pkt;
 170
 171         vsock_core_unregister(&loopback_transport.transport);
 172
 173         flush_work(&vsock->pkt_work);
 174
 175         spin_lock_bh(&vsock->pkt_list_lock);
 176         while (!list_empty(&vsock->pkt_list)) {
 177                 pkt = list_first_entry(&vsock->pkt_list,
 178                                        struct virtio_vsock_pkt, list);
 179                 list_del(&pkt->list);
 180                 virtio_transport_free_pkt(pkt);
 181         }
 182         spin_unlock_bh(&vsock->pkt_list_lock);
 183
 184         destroy_workqueue(vsock->workqueue);
 185 }
 186
 187 module_init(vsock_loopback_init);
 188 module_exit(vsock_loopback_exit);
 189 MODULE_LICENSE("GPL v2");
 190 MODULE_AUTHOR("Stefano Garzarella <sgarzare@redhat.com>");
 191 MODULE_DESCRIPTION("loopback transport for vsock");
 192 MODULE_ALIAS_NETPROTO(PF_VSOCK);