conn: make binds replacable

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

conn/conn_default.go

@@ -1,171 +0,0 @@
-// +build !linux android
-
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
- */
-
-package conn
-
-import (
-	"errors"
-	"net"
-	"syscall"
-)
-
-/* This code is meant to be a temporary solution
- * on platforms for which the sticky socket / source caching behavior
- * has not yet been implemented.
- *
- * See conn_linux.go for an implementation on the linux platform.
- */
-
-type nativeBind struct {
-	ipv4       *net.UDPConn
-	ipv6       *net.UDPConn
-	blackhole4 bool
-	blackhole6 bool
-}
-
-type NativeEndpoint net.UDPAddr
-
-var _ Bind = (*nativeBind)(nil)
-var _ Endpoint = (*NativeEndpoint)(nil)
-
-func CreateEndpoint(s string) (Endpoint, error) {
-	addr, err := parseEndpoint(s)
-	return (*NativeEndpoint)(addr), err
-}
-
-func (*NativeEndpoint) ClearSrc() {}
-
-func (e *NativeEndpoint) DstIP() net.IP {
-	return (*net.UDPAddr)(e).IP
-}
-
-func (e *NativeEndpoint) SrcIP() net.IP {
-	return nil // not supported
-}
-
-func (e *NativeEndpoint) DstToBytes() []byte {
-	addr := (*net.UDPAddr)(e)
-	out := addr.IP.To4()
-	if out == nil {
-		out = addr.IP
-	}
-	out = append(out, byte(addr.Port&0xff))
-	out = append(out, byte((addr.Port>>8)&0xff))
-	return out
-}
-
-func (e *NativeEndpoint) DstToString() string {
-	return (*net.UDPAddr)(e).String()
-}
-
-func (e *NativeEndpoint) SrcToString() string {
-	return ""
-}
-
-func listenNet(network string, port int) (*net.UDPConn, int, error) {
-	conn, err := net.ListenUDP(network, &net.UDPAddr{Port: port})
-	if err != nil {
-		return nil, 0, err
-	}
-
-	// Retrieve port.
-	laddr := conn.LocalAddr()
-	uaddr, err := net.ResolveUDPAddr(
-		laddr.Network(),
-		laddr.String(),
-	)
-	if err != nil {
-		return nil, 0, err
-	}
-	return conn, uaddr.Port, nil
-}
-
-func createBind(uport uint16) (Bind, uint16, error) {
-	var err error
-	var bind nativeBind
-	var tries int
-
-again:
-	port := int(uport)
-
-	bind.ipv4, port, err = listenNet("udp4", port)
-	if err != nil && !errors.Is(err, syscall.EAFNOSUPPORT) {
-		return nil, 0, err
-	}
-
-	bind.ipv6, port, err = listenNet("udp6", port)
-	if uport == 0 && err != nil && errors.Is(err, syscall.EADDRINUSE) && tries < 100 {
-		bind.ipv4.Close()
-		tries++
-		goto again
-	}
-	if err != nil && !errors.Is(err, syscall.EAFNOSUPPORT) {
-		bind.ipv4.Close()
-		bind.ipv4 = nil
-		return nil, 0, err
-	}
-
-	return &bind, uint16(port), nil
-}
-
-func (bind *nativeBind) Close() error {
-	var err1, err2 error
-	if bind.ipv4 != nil {
-		err1 = bind.ipv4.Close()
-	}
-	if bind.ipv6 != nil {
-		err2 = bind.ipv6.Close()
-	}
-	if err1 != nil {
-		return err1
-	}
-	return err2
-}
-
-func (bind *nativeBind) LastMark() uint32 { return 0 }
-
-func (bind *nativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
-	if bind.ipv4 == nil {
-		return 0, nil, syscall.EAFNOSUPPORT
-	}
-	n, endpoint, err := bind.ipv4.ReadFromUDP(buff)
-	if endpoint != nil {
-		endpoint.IP = endpoint.IP.To4()
-	}
-	return n, (*NativeEndpoint)(endpoint), err
-}
-
-func (bind *nativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
-	if bind.ipv6 == nil {
-		return 0, nil, syscall.EAFNOSUPPORT
-	}
-	n, endpoint, err := bind.ipv6.ReadFromUDP(buff)
-	return n, (*NativeEndpoint)(endpoint), err
-}
-
-func (bind *nativeBind) Send(buff []byte, endpoint Endpoint) error {
-	var err error
-	nend := endpoint.(*NativeEndpoint)
-	if nend.IP.To4() != nil {
-		if bind.ipv4 == nil {
-			return syscall.EAFNOSUPPORT
-		}
-		if bind.blackhole4 {
-			return nil
-		}
-		_, err = bind.ipv4.WriteToUDP(buff, (*net.UDPAddr)(nend))
-	} else {
-		if bind.ipv6 == nil {
-			return syscall.EAFNOSUPPORT
-		}
-		if bind.blackhole6 {
-			return nil
-		}
-		_, err = bind.ipv6.WriteToUDP(buff, (*net.UDPAddr)(nend))
-	}
-	return err
-}