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
|
// Copyright 2015 Matthew Holt and The Caddy 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.
// TODO: Go 1.19 introduced the "unix" build tag. We have to support Go 1.18 until Go 1.20 is released.
// When Go 1.19 is our minimum, remove this build tag, since "_unix" in the filename will do this.
// (see also change needed in listen.go)
//go:build aix || android || darwin || dragonfly || freebsd || hurd || illumos || ios || linux || netbsd || openbsd || solaris
package caddy
import (
"context"
"errors"
"io/fs"
"net"
"sync/atomic"
"syscall"
"go.uber.org/zap"
"golang.org/x/sys/unix"
)
// reuseUnixSocket copies and reuses the unix domain socket (UDS) if we already
// have it open; if not, unlink it so we can have it. No-op if not a unix network.
func reuseUnixSocket(network, addr string) (any, error) {
if !isUnixNetwork(network) {
return nil, nil
}
socketKey := listenerKey(network, addr)
socket, exists := unixSockets[socketKey]
if exists {
// make copy of file descriptor
socketFile, err := socket.File() // does dup() deep down
if err != nil {
return nil, err
}
// use copied fd to make new Listener or PacketConn, then replace
// it in the map so that future copies always come from the most
// recent fd (as the previous ones will be closed, and we'd get
// "use of closed network connection" errors) -- note that we
// preserve the *pointer* to the counter (not just the value) so
// that all socket wrappers will refer to the same value
switch unixSocket := socket.(type) {
case *unixListener:
ln, err := net.FileListener(socketFile)
if err != nil {
return nil, err
}
atomic.AddInt32(unixSocket.count, 1)
unixSockets[socketKey] = &unixListener{ln.(*net.UnixListener), socketKey, unixSocket.count}
case *unixConn:
pc, err := net.FilePacketConn(socketFile)
if err != nil {
return nil, err
}
atomic.AddInt32(unixSocket.count, 1)
unixSockets[socketKey] = &unixConn{pc.(*net.UnixConn), addr, socketKey, unixSocket.count}
}
return unixSockets[socketKey], nil
}
// from what I can tell after some quick research, it's quite common for programs to
// leave their socket file behind after they close, so the typical pattern is to
// unlink it before you bind to it -- this is often crucial if the last program using
// it was killed forcefully without a chance to clean up the socket, but there is a
// race, as the comment in net.UnixListener.close() explains... oh well, I guess?
if err := syscall.Unlink(addr); err != nil && !errors.Is(err, fs.ErrNotExist) {
return nil, err
}
return nil, nil
}
func listenTCPOrUnix(ctx context.Context, lnKey string, network, address string, config net.ListenConfig) (net.Listener, error) {
// wrap any Control function set by the user so we can also add our reusePort control without clobbering theirs
oldControl := config.Control
config.Control = func(network, address string, c syscall.RawConn) error {
if oldControl != nil {
if err := oldControl(network, address, c); err != nil {
return err
}
}
return reusePort(network, address, c)
}
return config.Listen(ctx, network, address)
}
// reusePort sets SO_REUSEPORT. Ineffective for unix sockets.
func reusePort(network, address string, conn syscall.RawConn) error {
if isUnixNetwork(network) {
return nil
}
return conn.Control(func(descriptor uintptr) {
if err := unix.SetsockoptInt(int(descriptor), unix.SOL_SOCKET, unix.SO_REUSEPORT, 1); err != nil {
Log().Error("setting SO_REUSEPORT",
zap.String("network", network),
zap.String("address", address),
zap.Uintptr("descriptor", descriptor),
zap.Error(err))
}
})
}
|
