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-rw-r--r--ipc/uapi_linux.go199
1 files changed, 199 insertions, 0 deletions
diff --git a/ipc/uapi_linux.go b/ipc/uapi_linux.go
new file mode 100644
index 0000000..8af3d8c
--- /dev/null
+++ b/ipc/uapi_linux.go
@@ -0,0 +1,199 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package ipc
+
+import (
+ "errors"
+ "fmt"
+ "golang.org/x/sys/unix"
+ "golang.zx2c4.com/wireguard/rwcancel"
+ "net"
+ "os"
+ "path"
+)
+
+var socketDirectory = "/var/run/wireguard"
+
+const (
+ IpcErrorIO = -int64(unix.EIO)
+ IpcErrorProtocol = -int64(unix.EPROTO)
+ IpcErrorInvalid = -int64(unix.EINVAL)
+ IpcErrorPortInUse = -int64(unix.EADDRINUSE)
+ socketName = "%s.sock"
+)
+
+type UAPIListener struct {
+ listener net.Listener // unix socket listener
+ connNew chan net.Conn
+ connErr chan error
+ inotifyFd int
+ inotifyRWCancel *rwcancel.RWCancel
+}
+
+func (l *UAPIListener) Accept() (net.Conn, error) {
+ for {
+ select {
+ case conn := <-l.connNew:
+ return conn, nil
+
+ case err := <-l.connErr:
+ return nil, err
+ }
+ }
+}
+
+func (l *UAPIListener) Close() error {
+ err1 := unix.Close(l.inotifyFd)
+ err2 := l.inotifyRWCancel.Cancel()
+ err3 := l.listener.Close()
+ if err1 != nil {
+ return err1
+ }
+ if err2 != nil {
+ return err2
+ }
+ return err3
+}
+
+func (l *UAPIListener) Addr() net.Addr {
+ return l.listener.Addr()
+}
+
+func UAPIListen(name string, file *os.File) (net.Listener, error) {
+
+ // wrap file in listener
+
+ listener, err := net.FileListener(file)
+ if err != nil {
+ return nil, err
+ }
+
+ if unixListener, ok := listener.(*net.UnixListener); ok {
+ unixListener.SetUnlinkOnClose(true)
+ }
+
+ uapi := &UAPIListener{
+ listener: listener,
+ connNew: make(chan net.Conn, 1),
+ connErr: make(chan error, 1),
+ }
+
+ // watch for deletion of socket
+
+ socketPath := path.Join(
+ socketDirectory,
+ fmt.Sprintf(socketName, name),
+ )
+
+ uapi.inotifyFd, err = unix.InotifyInit()
+ if err != nil {
+ return nil, err
+ }
+
+ _, err = unix.InotifyAddWatch(
+ uapi.inotifyFd,
+ socketPath,
+ unix.IN_ATTRIB|
+ unix.IN_DELETE|
+ unix.IN_DELETE_SELF,
+ )
+
+ if err != nil {
+ return nil, err
+ }
+
+ uapi.inotifyRWCancel, err = rwcancel.NewRWCancel(uapi.inotifyFd)
+ if err != nil {
+ unix.Close(uapi.inotifyFd)
+ return nil, err
+ }
+
+ go func(l *UAPIListener) {
+ var buff [0]byte
+ for {
+ // start with lstat to avoid race condition
+ if _, err := os.Lstat(socketPath); os.IsNotExist(err) {
+ l.connErr <- err
+ return
+ }
+ _, err := uapi.inotifyRWCancel.Read(buff[:])
+ if err != nil {
+ l.connErr <- err
+ return
+ }
+ }
+ }(uapi)
+
+ // watch for new connections
+
+ go func(l *UAPIListener) {
+ for {
+ conn, err := l.listener.Accept()
+ if err != nil {
+ l.connErr <- err
+ break
+ }
+ l.connNew <- conn
+ }
+ }(uapi)
+
+ return uapi, nil
+}
+
+func UAPIOpen(name string) (*os.File, error) {
+
+ // check if path exist
+
+ err := os.MkdirAll(socketDirectory, 0755)
+ if err != nil && !os.IsExist(err) {
+ return nil, err
+ }
+
+ // open UNIX socket
+
+ socketPath := path.Join(
+ socketDirectory,
+ fmt.Sprintf(socketName, name),
+ )
+
+ addr, err := net.ResolveUnixAddr("unix", socketPath)
+ if err != nil {
+ return nil, err
+ }
+
+ oldUmask := unix.Umask(0077)
+ listener, err := func() (*net.UnixListener, error) {
+
+ // initial connection attempt
+
+ listener, err := net.ListenUnix("unix", addr)
+ if err == nil {
+ return listener, nil
+ }
+
+ // check if socket already active
+
+ _, err = net.Dial("unix", socketPath)
+ if err == nil {
+ return nil, errors.New("unix socket in use")
+ }
+
+ // cleanup & attempt again
+
+ err = os.Remove(socketPath)
+ if err != nil {
+ return nil, err
+ }
+ return net.ListenUnix("unix", addr)
+ }()
+ unix.Umask(oldUmask)
+
+ if err != nil {
+ return nil, err
+ }
+
+ return listener.File()
+}