1 /* SPDX-License-Identifier: MIT
2 *
3 * Copyright (C) 2017-2025 WireGuard LLC. All Rights Reserved.
4 */
5 6 package conn
7 8 import (
9 "net"
10 "syscall"
11 )
12 13 // UDP socket read/write buffer size (7MB). The value of 7MB is chosen as it is
14 // the max supported by a default configuration of macOS. Some platforms will
15 // silently clamp the value to other maximums, such as linux clamping to
16 // net.core.{r,w}mem_max (see _linux.go for additional implementation that works
17 // around this limitation)
18 const socketBufferSize = 7 << 20
19 20 // controlFn is the callback function signature from net.ListenConfig.Control.
21 // It is used to apply platform specific configuration to the socket prior to
22 // bind.
23 type controlFn func(network, address string, c syscall.RawConn) error
24 25 // controlFns is a list of functions that are called from the listen config
26 // that can apply socket options.
27 var controlFns = []controlFn{}
28 29 // listenConfig returns a net.ListenConfig that applies the controlFns to the
30 // socket prior to bind. This is used to apply socket buffer sizing and packet
31 // information OOB configuration for sticky sockets.
32 func listenConfig() *net.ListenConfig {
33 return &net.ListenConfig{
34 Control: func(network, address string, c syscall.RawConn) error {
35 for _, fn := range controlFns {
36 if err := fn(network, address, c); err != nil {
37 return err
38 }
39 }
40 return nil
41 },
42 }
43 }
44