[PATCH net-next 5/6] vsock: use local transport when it is loaded

Stefano Garzarella
2019-11-19T11:01:48Z

Now that we have a transport that can handle the local communication,
we can use it when it is loaded.

A socket will use the local transport (loopback) when the remote
CID is:
- equal to VMADDR_CID_LOCAL
- or equal to transport_g2h->get_local_cid(), if transport_g2h
is loaded (this allows us to keep the same behavior implemented
by virtio and vmci transports)
- or equal to VMADDR_CID_HOST, if transport_g2h is not loaded

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
net/vmw_vsock/af_vsock.c | 32 ++++++++++++++++++++++++++------
1 file changed, 26 insertions(+), 6 deletions(-)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index c9e5bad59dc1..40bbb2a17e3d 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -388,6 +388,21 @@ void vsock_enqueue_accept(struct sock *listener, struct sock *connected)
}
EXPORT_SYMBOL_GPL(vsock_enqueue_accept);

+static bool vsock_use_local_transport(unsigned int remote_cid)
+{
+ if (!transport_local)
+ return false;
+
+ if (remote_cid == VMADDR_CID_LOCAL)
+ return true;
+
+ if (transport_g2h) {
+ return remote_cid == transport_g2h->get_local_cid();
+ } else {
+ return remote_cid == VMADDR_CID_HOST;
+ }
+}
+
static void vsock_deassign_transport(struct vsock_sock *vsk)
{
if (!vsk->transport)
@@ -404,9 +419,10 @@ static void vsock_deassign_transport(struct vsock_sock *vsk)
* (e.g. during the connect() or when a connection request on a listener
* socket is received).
* The vsk->remote_addr is used to decide which transport to use:
- * - remote CID <= VMADDR_CID_HOST will use guest->host transport;
- * - remote CID == local_cid (guest->host transport) will use guest->host
- * transport for loopback (host->guest transports don't support loopback);
+ * - remote CID == VMADDR_CID_LOCAL or g2h->local_cid or VMADDR_CID_HOST if
+ * g2h is not loaded, will use local transport;
+ * - remote CID == VMADDR_CID_HOST or VMADDR_CID_HYPERVISOR, will use
+ * guest->host transport;
* - remote CID > VMADDR_CID_HOST will use host->guest transport;
*/
int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
@@ -420,9 +436,10 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
new_transport = transport_dgram;
break;
case SOCK_STREAM:
- if (remote_cid <= VMADDR_CID_HOST ||
- (transport_g2h &&
- remote_cid == transport_g2h->get_local_cid()))
+ if (vsock_use_local_transport(remote_cid))
+ new_transport = transport_local;
+ else if (remote_cid == VMADDR_CID_HOST ||
+ remote_cid == VMADDR_CID_HYPERVISOR)
new_transport = transport_g2h;
else
new_transport = transport_h2g;
@@ -459,6 +476,9 @@ bool vsock_find_cid(unsigned int cid)
if (transport_h2g && cid == VMADDR_CID_HOST)
return true;

+ if (transport_local && cid == VMADDR_CID_LOCAL)
+ return true;
+
return false;
}
EXPORT_SYMBOL_GPL(vsock_find_cid);
--
2.21.0