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system_dialer.go
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system_dialer.go
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package internet
import (
"context"
"syscall"
"time"
"v2ray.com/core/common/net"
"v2ray.com/core/common/session"
)
var (
effectiveSystemDialer SystemDialer = &DefaultSystemDialer{}
)
type SystemDialer interface {
Dial(ctx context.Context, source net.Address, destination net.Destination, sockopt *SocketConfig) (net.Conn, error)
}
type DefaultSystemDialer struct {
controllers []controller
}
func resolveSrcAddr(network net.Network, src net.Address) net.Addr {
if src == nil || src == net.AnyIP {
return nil
}
if network == net.Network_TCP {
return &net.TCPAddr{
IP: src.IP(),
Port: 0,
}
}
return &net.UDPAddr{
IP: src.IP(),
Port: 0,
}
}
func hasBindAddr(sockopt *SocketConfig) bool {
return sockopt != nil && len(sockopt.BindAddress) > 0 && sockopt.BindPort > 0
}
func (d *DefaultSystemDialer) Dial(ctx context.Context, src net.Address, dest net.Destination, sockopt *SocketConfig) (net.Conn, error) {
if dest.Network == net.Network_UDP && !hasBindAddr(sockopt) {
srcAddr := resolveSrcAddr(net.Network_UDP, src)
if srcAddr == nil {
srcAddr = &net.UDPAddr{
IP: []byte{0, 0, 0, 0},
Port: 0,
}
}
packetConn, err := ListenSystemPacket(ctx, srcAddr, sockopt)
if err != nil {
return nil, err
}
destAddr, err := net.ResolveUDPAddr("udp", dest.NetAddr())
if err != nil {
return nil, err
}
return &packetConnWrapper{
conn: packetConn,
dest: destAddr,
}, nil
}
dialer := &net.Dialer{
Timeout: time.Second * 16,
DualStack: true,
LocalAddr: resolveSrcAddr(dest.Network, src),
}
if sockopt != nil || len(d.controllers) > 0 {
dialer.Control = func(network, address string, c syscall.RawConn) error {
return c.Control(func(fd uintptr) {
if sockopt != nil {
if err := applyOutboundSocketOptions(network, address, fd, sockopt); err != nil {
newError("failed to apply socket options").Base(err).WriteToLog(session.ExportIDToError(ctx))
}
if dest.Network == net.Network_UDP && hasBindAddr(sockopt) {
if err := bindAddr(fd, sockopt.BindAddress, sockopt.BindPort); err != nil {
newError("failed to bind source address to ", sockopt.BindAddress).Base(err).WriteToLog(session.ExportIDToError(ctx))
}
}
}
for _, ctl := range d.controllers {
if err := ctl(network, address, fd); err != nil {
newError("failed to apply external controller").Base(err).WriteToLog(session.ExportIDToError(ctx))
}
}
})
}
}
return dialer.DialContext(ctx, dest.Network.SystemString(), dest.NetAddr())
}
type packetConnWrapper struct {
conn net.PacketConn
dest net.Addr
}
func (c *packetConnWrapper) Close() error {
return c.conn.Close()
}
func (c *packetConnWrapper) LocalAddr() net.Addr {
return c.conn.LocalAddr()
}
func (c *packetConnWrapper) RemoteAddr() net.Addr {
return c.dest
}
func (c *packetConnWrapper) Write(p []byte) (int, error) {
return c.conn.WriteTo(p, c.dest)
}
func (c *packetConnWrapper) Read(p []byte) (int, error) {
n, _, err := c.conn.ReadFrom(p)
return n, err
}
func (c *packetConnWrapper) SetDeadline(t time.Time) error {
return c.conn.SetDeadline(t)
}
func (c *packetConnWrapper) SetReadDeadline(t time.Time) error {
return c.conn.SetReadDeadline(t)
}
func (c *packetConnWrapper) SetWriteDeadline(t time.Time) error {
return c.conn.SetWriteDeadline(t)
}
type SystemDialerAdapter interface {
Dial(network string, address string) (net.Conn, error)
}
type SimpleSystemDialer struct {
adapter SystemDialerAdapter
}
func WithAdapter(dialer SystemDialerAdapter) SystemDialer {
return &SimpleSystemDialer{
adapter: dialer,
}
}
func (v *SimpleSystemDialer) Dial(ctx context.Context, src net.Address, dest net.Destination, sockopt *SocketConfig) (net.Conn, error) {
return v.adapter.Dial(dest.Network.SystemString(), dest.NetAddr())
}
// UseAlternativeSystemDialer replaces the current system dialer with a given one.
// Caller must ensure there is no race condition.
//
// v2ray:api:stable
func UseAlternativeSystemDialer(dialer SystemDialer) {
if dialer == nil {
effectiveSystemDialer = &DefaultSystemDialer{}
}
effectiveSystemDialer = dialer
}
// RegisterDialerController adds a controller to the effective system dialer.
// The controller can be used to operate on file descriptors before they are put into use.
// It only works when effective dialer is the default dialer.
//
// v2ray:api:beta
func RegisterDialerController(ctl func(network, address string, fd uintptr) error) error {
if ctl == nil {
return newError("nil listener controller")
}
dialer, ok := effectiveSystemDialer.(*DefaultSystemDialer)
if !ok {
return newError("RegisterListenerController not supported in custom dialer")
}
dialer.controllers = append(dialer.controllers, ctl)
return nil
}