Move Linux client & common packages into a public repo.

safesocket/basic_test.go

@@ -0,0 +1,63 @@
+// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package safesocket
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestBasics(t *testing.T) {
+	fmt.Printf("listening2...\n")
+	l, port, err := Listen("COOKIE", "Tailscale", "test", 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	fmt.Printf("listened.\n")
+
+	go func() {
+		fmt.Printf("accepting...\n")
+		s, err := l.Accept()
+		if err != nil {
+			t.Fatal(err)
+		}
+		fmt.Printf("accepted.\n")
+		l.Close()
+		s.Write([]byte("hello"))
+		fmt.Printf("server wrote.\n")
+
+		b := make([]byte, 1024)
+		n, err := s.Read(b)
+		if err != nil {
+			t.Fatal(err)
+		}
+		fmt.Printf("server read %d bytes.\n", n)
+		if string(b[:n]) != "world" {
+			t.Fatalf("got %#v, expected %#v\n", string(b[:n]), "world")
+		}
+		s.Close()
+	}()
+
+	fmt.Printf("connecting...\n")
+	c, err := Connect("COOKIE", "Tailscale", "test", port)
+	if err != nil {
+		t.Fatal(err)
+	}
+	fmt.Printf("connected.\n")
+	c.Write([]byte("world"))
+	fmt.Printf("client wrote.\n")
+
+	b := make([]byte, 1024)
+	n, err := c.Read(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	fmt.Printf("client read %d bytes.\n", n)
+	if string(b[:n]) != "hello" {
+		t.Fatalf("got %#v, expected %#v\n", string(b[:n]), "hello")
+	}
+
+	c.Close()
+}

safesocket/pipe_windows.go

@@ -0,0 +1,59 @@
+// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package safesocket
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"syscall"
+)
+
+func path(vendor, name string, port uint16) string {
+	return fmt.Sprintf("127.0.0.1:%v", port)
+}
+
+func ConnCloseRead(c net.Conn) error {
+	return c.(*net.TCPConn).CloseRead()
+}
+
+func ConnCloseWrite(c net.Conn) error {
+	return c.(*net.TCPConn).CloseWrite()
+}
+
+// TODO(apenwarr): handle magic cookie auth
+func Connect(cookie, vendor, name string, port uint16) (net.Conn, error) {
+	p := path(vendor, name, port)
+	pipe, err := net.Dial("tcp", p)
+	if err != nil {
+		return nil, err
+	}
+	return pipe, err
+}
+
+func setFlags(network, address string, c syscall.RawConn) error {
+	return c.Control(func(fd uintptr) {
+		syscall.SetsockoptInt(syscall.Handle(fd), syscall.SOL_SOCKET,
+			syscall.SO_REUSEADDR, 1)
+	})
+}
+
+// TODO(apenwarr): use named pipes instead of sockets?
+//   I tried to use winio.ListenPipe() here, but that code is a disaster,
+//   built on top of an API that's a disaster. So for now we'll hack it by
+//   just always using a TCP session on a fixed port on localhost. As a
+//   result, on Windows we ignore the vendor and name strings.
+// TODO(apenwarr): handle magic cookie auth
+func Listen(cookie, vendor, name string, port uint16) (net.Listener, uint16, error) {
+	lc := net.ListenConfig{
+		Control: setFlags,
+	}
+	p := path(vendor, name, port)
+	pipe, err := lc.Listen(context.Background(), "tcp", p)
+	if err != nil {
+		return nil, 0, err
+	}
+	return pipe, uint16(pipe.Addr().(*net.TCPAddr).Port), err
+}

safesocket/unixsocket.go

@@ -0,0 +1,61 @@
+// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !windows
+
+package safesocket
+
+import (
+	"fmt"
+	"net"
+	"os"
+)
+
+func path(vendor, name string) string {
+	return fmt.Sprintf("%s-%s.sock", vendor, name)
+}
+
+func ConnCloseRead(c net.Conn) error {
+	return c.(*net.UnixConn).CloseRead()
+}
+
+func ConnCloseWrite(c net.Conn) error {
+	return c.(*net.UnixConn).CloseWrite()
+}
+
+// TODO(apenwarr): handle magic cookie auth
+func Connect(cookie, vendor, name string, port uint16) (net.Conn, error) {
+	pipe, err := net.Dial("unix", path(vendor, name))
+	if err != nil {
+		return nil, err
+	}
+	return pipe, err
+}
+
+// TODO(apenwarr): handle magic cookie auth
+func Listen(cookie, vendor, name string, port uint16) (net.Listener, uint16, error) {
+	// Unix sockets hang around in the filesystem even after nobody
+	// is listening on them. (Which is really unfortunate but long-
+	// entrenched semantics.) Try connecting first; if it works, then
+	// the socket is still live, so let's not replace it. If it doesn't
+	// work, then replace it.
+	//
+	// Note that there's a race condition between these two steps. A
+	// "proper" daemon usually uses a dance involving pidfiles to first
+	// ensure that no other instances of itself are running, but that's
+	// beyond the scope of our simple socket library.
+	p := path(vendor, name)
+	c, err := net.Dial("unix", p)
+	if err == nil {
+		c.Close()
+		return nil, 0, fmt.Errorf("%v: address already in use", p)
+	}
+	_ = os.Remove(p)
+	pipe, err := net.Listen("unix", p)
+	if err != nil {
+		return nil, 0, err
+	}
+	os.Chmod(p, 0666)
+	return pipe, 0, err
+}