1 files changed, 138 insertions, 0 deletions
diff --git a/pkg/sentry/socket/netlink/socket_vfs2.go b/pkg/sentry/socket/netlink/socket_vfs2.go
new file mode 100644
index 000000000..b854bf990
--- /dev/null
+++ b/pkg/sentry/socket/netlink/socket_vfs2.go
@@ -0,0 +1,138 @@
+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package netlink
+
+import (
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/sentry/arch"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/socket"
+	"gvisor.dev/gvisor/pkg/sentry/socket/unix"
+	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/syserr"
+	"gvisor.dev/gvisor/pkg/syserror"
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/usermem"
+	"gvisor.dev/gvisor/pkg/waiter"
+)
+
+// SocketVFS2 is the base VFS2 socket type for netlink sockets.
+//
+// This implementation only supports userspace sending and receiving messages
+// to/from the kernel.
+//
+// SocketVFS2 implements socket.SocketVFS2 and transport.Credentialer.
+type SocketVFS2 struct {
+	vfsfd vfs.FileDescription
+	vfs.FileDescriptionDefaultImpl
+	vfs.DentryMetadataFileDescriptionImpl
+
+	socketOpsCommon
+}
+
+var _ socket.SocketVFS2 = (*SocketVFS2)(nil)
+var _ transport.Credentialer = (*SocketVFS2)(nil)
+
+// NewVFS2 creates a new SocketVFS2.
+func NewVFS2(t *kernel.Task, skType linux.SockType, protocol Protocol) (*SocketVFS2, *syserr.Error) {
+	// Datagram endpoint used to buffer kernel -> user messages.
+	ep := transport.NewConnectionless(t)
+
+	// Bind the endpoint for good measure so we can connect to it. The
+	// bound address will never be exposed.
+	if err := ep.Bind(tcpip.FullAddress{Addr: "dummy"}, nil); err != nil {
+		ep.Close()
+		return nil, err
+	}
+
+	// Create a connection from which the kernel can write messages.
+	connection, err := ep.(transport.BoundEndpoint).UnidirectionalConnect(t)
+	if err != nil {
+		ep.Close()
+		return nil, err
+	}
+
+	return &SocketVFS2{
+		socketOpsCommon: socketOpsCommon{
+			ports:          t.Kernel().NetlinkPorts(),
+			protocol:       protocol,
+			skType:         skType,
+			ep:             ep,
+			connection:     connection,
+			sendBufferSize: defaultSendBufferSize,
+		},
+	}, nil
+}
+
+// Readiness implements waiter.Waitable.Readiness.
+func (s *SocketVFS2) Readiness(mask waiter.EventMask) waiter.EventMask {
+	return s.socketOpsCommon.Readiness(mask)
+}
+
+// EventRegister implements waiter.Waitable.EventRegister.
+func (s *SocketVFS2) EventRegister(e *waiter.Entry, mask waiter.EventMask) {
+	s.socketOpsCommon.EventRegister(e, mask)
+}
+
+// EventUnregister implements waiter.Waitable.EventUnregister.
+func (s *SocketVFS2) EventUnregister(e *waiter.Entry) {
+	s.socketOpsCommon.EventUnregister(e)
+}
+
+// Ioctl implements vfs.FileDescriptionImpl.
+func (*SocketVFS2) Ioctl(context.Context, usermem.IO, arch.SyscallArguments) (uintptr, error) {
+	// TODO(b/68878065): no ioctls supported.
+	return 0, syserror.ENOTTY
+}
+
+// PRead implements vfs.FileDescriptionImpl.
+func (s *SocketVFS2) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
+	return 0, syserror.ESPIPE
+}
+
+// Read implements vfs.FileDescriptionImpl.
+func (s *SocketVFS2) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
+	// All flags other than RWF_NOWAIT should be ignored.
+	// TODO(gvisor.dev/issue/2601): Support RWF_NOWAIT.
+	if opts.Flags != 0 {
+		return 0, syserror.EOPNOTSUPP
+	}
+
+	if dst.NumBytes() == 0 {
+		return 0, nil
+	}
+	return dst.CopyOutFrom(ctx, &unix.EndpointReader{
+		Endpoint: s.ep,
+	})
+}
+
+// PWrite implements vfs.FileDescriptionImpl.
+func (s *SocketVFS2) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
+	return 0, syserror.ESPIPE
+}
+
+// Write implements vfs.FileDescriptionImpl.
+func (s *SocketVFS2) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
+	// All flags other than RWF_NOWAIT should be ignored.
+	// TODO(gvisor.dev/issue/2601): Support RWF_NOWAIT.
+	if opts.Flags != 0 {
+		return 0, syserror.EOPNOTSUPP
+	}
+
+	n, err := s.sendMsg(ctx, src, nil, 0, socket.ControlMessages{})
+	return int64(n), err.ToError()
+}