[PATCH net-next 4/6] vsock: add vsock_loopback transport

Stefano Garzarella
2019-11-19T11:01:57Z

This patch adds a new vsock_loopback transport to handle local
communication.
This transport is based on the loopback implementation of
virtio_transport, so it uses the virtio_transport_common APIs
to interface with the vsock core.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
MAINTAINERS | 1 +
net/vmw_vsock/Kconfig | 12 ++
net/vmw_vsock/Makefile | 1 +
net/vmw_vsock/vsock_loopback.c | 217 +++++++++++++++++++++++++++++++++
4 files changed, 231 insertions(+)
create mode 100644 net/vmw_vsock/vsock_loopback.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 760049454a23..c2a3dc3113ba 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17239,6 +17239,7 @@ F: net/vmw_vsock/diag.c
F: net/vmw_vsock/af_vsock_tap.c
F: net/vmw_vsock/virtio_transport_common.c
F: net/vmw_vsock/virtio_transport.c
+F: net/vmw_vsock/vsock_loopback.c
F: drivers/net/vsockmon.c
F: drivers/vhost/vsock.c
F: tools/testing/vsock/
diff --git a/net/vmw_vsock/Kconfig b/net/vmw_vsock/Kconfig
index 8abcb815af2d..56356d2980c8 100644
--- a/net/vmw_vsock/Kconfig
+++ b/net/vmw_vsock/Kconfig
@@ -26,6 +26,18 @@ config VSOCKETS_DIAG

Enable this module so userspace applications can query open sockets.

+config VSOCKETS_LOOPBACK
+ tristate "Virtual Sockets loopback transport"
+ depends on VSOCKETS
+ default y
+ select VIRTIO_VSOCKETS_COMMON
+ help
+ This module implements a loopback transport for Virtual Sockets,
+ using vmw_vsock_virtio_transport_common.
+
+ To compile this driver as a module, choose M here: the module
+ will be called vsock_loopback. If unsure, say N.
+
config VMWARE_VMCI_VSOCKETS
tristate "VMware VMCI transport for Virtual Sockets"
depends on VSOCKETS && VMWARE_VMCI
diff --git a/net/vmw_vsock/Makefile b/net/vmw_vsock/Makefile
index 7c6f9a0b67b0..6a943ec95c4a 100644
--- a/net/vmw_vsock/Makefile
+++ b/net/vmw_vsock/Makefile
@@ -5,6 +5,7 @@ obj-$(CONFIG_VMWARE_VMCI_VSOCKETS) += vmw_vsock_vmci_transport.o
obj-$(CONFIG_VIRTIO_VSOCKETS) += vmw_vsock_virtio_transport.o
obj-$(CONFIG_VIRTIO_VSOCKETS_COMMON) += vmw_vsock_virtio_transport_common.o
obj-$(CONFIG_HYPERV_VSOCKETS) += hv_sock.o
+obj-$(CONFIG_VSOCKETS_LOOPBACK) += vsock_loopback.o

vsock-y += af_vsock.o af_vsock_tap.o vsock_addr.o

diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c
new file mode 100644
index 000000000000..3d1c1a88305f
--- /dev/null
+++ b/net/vmw_vsock/vsock_loopback.c
@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * loopback transport for vsock using virtio_transport_common APIs
+ *
+ * Copyright (C) 2013-2019 Red Hat, Inc.
+ * Author: Asias He <asias@redhat.com>
+ * Stefan Hajnoczi <stefanha@redhat.com>
+ * Stefano Garzarella <sgarzare@redhat.com>
+ *
+ */
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/virtio_vsock.h>
+
+static struct workqueue_struct *vsock_loopback_workqueue;
+static struct vsock_loopback *the_vsock_loopback;
+
+struct vsock_loopback {
+ spinlock_t loopback_list_lock; /* protects loopback_list */
+ struct list_head loopback_list;
+ struct work_struct loopback_work;
+};
+
+static u32 vsock_loopback_get_local_cid(void)
+{
+ return VMADDR_CID_LOCAL;
+}
+
+static int vsock_loopback_send_pkt(struct virtio_vsock_pkt *pkt)
+{
+ struct vsock_loopback *vsock;
+ int len = pkt->len;
+
+ rcu_read_lock();
+ vsock = rcu_dereference(the_vsock_loopback);
+ if (!vsock) {
+ virtio_transport_free_pkt(pkt);
+ len = -ENODEV;
+ goto out_rcu;
+ }
+
+ spin_lock_bh(&vsock->loopback_list_lock);
+ list_add_tail(&pkt->list, &vsock->loopback_list);
+ spin_unlock_bh(&vsock->loopback_list_lock);
+
+ queue_work(vsock_loopback_workqueue, &vsock->loopback_work);
+
+out_rcu:
+ rcu_read_unlock();
+ return len;
+}
+
+static int vsock_loopback_cancel_pkt(struct vsock_sock *vsk)
+{
+ struct vsock_loopback *vsock;
+ struct virtio_vsock_pkt *pkt, *n;
+ int ret;
+ LIST_HEAD(freeme);
+
+ rcu_read_lock();
+ vsock = rcu_dereference(the_vsock_loopback);
+ if (!vsock) {
+ ret = -ENODEV;
+ goto out_rcu;
+ }
+
+ spin_lock_bh(&vsock->loopback_list_lock);
+ list_for_each_entry_safe(pkt, n, &vsock->loopback_list, list) {
+ if (pkt->vsk != vsk)
+ continue;
+ list_move(&pkt->list, &freeme);
+ }
+ spin_unlock_bh(&vsock->loopback_list_lock);
+
+ list_for_each_entry_safe(pkt, n, &freeme, list) {
+ list_del(&pkt->list);
+ virtio_transport_free_pkt(pkt);
+ }
+
+ ret = 0;
+
+out_rcu:
+ rcu_read_unlock();
+ return ret;
+}
+
+static struct virtio_transport loopback_transport = {
+ .transport = {
+ .module = THIS_MODULE,
+
+ .get_local_cid = vsock_loopback_get_local_cid,
+
+ .init = virtio_transport_do_socket_init,
+ .destruct = virtio_transport_destruct,
+ .release = virtio_transport_release,
+ .connect = virtio_transport_connect,
+ .shutdown = virtio_transport_shutdown,
+ .cancel_pkt = vsock_loopback_cancel_pkt,
+
+ .dgram_bind = virtio_transport_dgram_bind,
+ .dgram_dequeue = virtio_transport_dgram_dequeue,
+ .dgram_enqueue = virtio_transport_dgram_enqueue,
+ .dgram_allow = virtio_transport_dgram_allow,
+
+ .stream_dequeue = virtio_transport_stream_dequeue,
+ .stream_enqueue = virtio_transport_stream_enqueue,
+ .stream_has_data = virtio_transport_stream_has_data,
+ .stream_has_space = virtio_transport_stream_has_space,
+ .stream_rcvhiwat = virtio_transport_stream_rcvhiwat,
+ .stream_is_active = virtio_transport_stream_is_active,
+ .stream_allow = virtio_transport_stream_allow,
+
+ .notify_poll_in = virtio_transport_notify_poll_in,
+ .notify_poll_out = virtio_transport_notify_poll_out,
+ .notify_recv_init = virtio_transport_notify_recv_init,
+ .notify_recv_pre_block = virtio_transport_notify_recv_pre_block,
+ .notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue,
+ .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
+ .notify_send_init = virtio_transport_notify_send_init,
+ .notify_send_pre_block = virtio_transport_notify_send_pre_block,
+ .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue,
+ .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
+ .notify_buffer_size = virtio_transport_notify_buffer_size,
+ },
+
+ .send_pkt = vsock_loopback_send_pkt,
+};
+
+static void vsock_loopback_work(struct work_struct *work)
+{
+ struct vsock_loopback *vsock =
+ container_of(work, struct vsock_loopback, loopback_work);
+ LIST_HEAD(pkts);
+
+ spin_lock_bh(&vsock->loopback_list_lock);
+ list_splice_init(&vsock->loopback_list, &pkts);
+ spin_unlock_bh(&vsock->loopback_list_lock);
+
+ while (!list_empty(&pkts)) {
+ struct virtio_vsock_pkt *pkt;
+
+ pkt = list_first_entry(&pkts, struct virtio_vsock_pkt, list);
+ list_del_init(&pkt->list);
+
+ virtio_transport_deliver_tap_pkt(pkt);
+ virtio_transport_recv_pkt(&loopback_transport, pkt);
+ }
+}
+
+static int __init vsock_loopback_init(void)
+{
+ struct vsock_loopback *vsock = NULL;
+ int ret;
+
+ vsock_loopback_workqueue = alloc_workqueue("vsock-loopback", 0, 0);
+ if (!vsock_loopback_workqueue)
+ return -ENOMEM;
+
+ vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
+ if (!vsock) {
+ ret = -ENOMEM;
+ goto out_wq;
+ }
+
+ spin_lock_init(&vsock->loopback_list_lock);
+ INIT_LIST_HEAD(&vsock->loopback_list);
+ INIT_WORK(&vsock->loopback_work, vsock_loopback_work);
+
+ rcu_assign_pointer(the_vsock_loopback, vsock);
+
+ ret = vsock_core_register(&loopback_transport.transport,
+ VSOCK_TRANSPORT_F_LOCAL);
+ if (ret)
+ goto out_free;
+
+ return 0;
+
+out_free:
+ rcu_assign_pointer(the_vsock_loopback, NULL);
+ kfree(vsock);
+out_wq:
+ destroy_workqueue(vsock_loopback_workqueue);
+ return ret;
+}
+
+static void __exit vsock_loopback_exit(void)
+{
+ struct vsock_loopback *vsock = the_vsock_loopback;
+ struct virtio_vsock_pkt *pkt;
+
+ vsock_core_unregister(&loopback_transport.transport);
+
+ rcu_assign_pointer(the_vsock_loopback, NULL);
+ synchronize_rcu();
+
+ spin_lock_bh(&vsock->loopback_list_lock);
+ while (!list_empty(&vsock->loopback_list)) {
+ pkt = list_first_entry(&vsock->loopback_list,
+ struct virtio_vsock_pkt, list);
+ list_del(&pkt->list);
+ virtio_transport_free_pkt(pkt);
+ }
+ spin_unlock_bh(&vsock->loopback_list_lock);
+
+ flush_work(&vsock->loopback_work);
+
+ kfree(vsock);
+ destroy_workqueue(vsock_loopback_workqueue);
+}
+
+module_init(vsock_loopback_init);
+module_exit(vsock_loopback_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Stefano Garzarella <sgarzare@redhat.com>");
+MODULE_DESCRIPTION("loopback transport for vsock");
+MODULE_ALIAS_NETPROTO(PF_VSOCK);
--
2.21.0