summaryrefslogtreecommitdiffhomepage
path: root/src/uapi_linux.go
blob: fd56b5a72364d9ce76a933de8244255ca0fc7287 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
package main

import (
	"errors"
	"fmt"
	"golang.org/x/sys/unix"
	"net"
	"os"
	"path"
)

const (
	ipcErrorIO         = -int64(unix.EIO)
	ipcErrorNotDefined = -int64(unix.ENODEV)
	ipcErrorProtocol   = -int64(unix.EPROTO)
	ipcErrorInvalid    = -int64(unix.EINVAL)
	socketDirectory    = "/var/run/wireguard"
	socketName         = "%s.sock"
)

/* TODO:
 * This code can be improved by using fsnotify once:
 * https://github.com/fsnotify/fsnotify/pull/205
 * Is merged
 */

type UAPIListener struct {
	listener  net.Listener // unix socket listener
	connNew   chan net.Conn
	connErr   chan error
	inotifyFd int
}

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 {
	return l.listener.Close()
}

func (l *UAPIListener) Addr() net.Addr {
	return nil
}

func connectUnixSocket(path string) (net.Listener, error) {

	// attempt inital connection

	listener, err := net.Listen("unix", path)
	if err == nil {
		return listener, nil
	}

	// check if active

	_, err = net.Dial("unix", path)
	if err == nil {
		return nil, errors.New("Unix socket in use")
	}

	// attempt cleanup

	err = os.Remove(path)
	if err != nil {
		return nil, err
	}

	return net.Listen("unix", path)
}

func NewUAPIListener(name string) (net.Listener, error) {

	// check if path exist

	err := os.MkdirAll(socketDirectory, 077)
	if err != nil && !os.IsExist(err) {
		return nil, err
	}

	// open UNIX socket

	socketPath := path.Join(
		socketDirectory,
		fmt.Sprintf(socketName, name),
	)

	listener, err := connectUnixSocket(socketPath)
	if err != nil {
		return nil, err
	}

	uapi := &UAPIListener{
		listener: listener,
		connNew:  make(chan net.Conn, 1),
		connErr:  make(chan error, 1),
	}

	// watch for deletion of socket

	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
	}

	go func(l *UAPIListener) {
		var buff [4096]byte
		for {
			unix.Read(uapi.inotifyFd, buff[:])
			if _, err := os.Lstat(socketPath); os.IsNotExist(err) {
				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
}