github.com/GFW-knocker/wireguard@v1.0.1/conn/controlfns.go (about) 1 /* SPDX-License-Identifier: MIT 2 * 3 * Copyright (C) 2017-2023 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 }