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freedom.go
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freedom.go
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package freedom
import (
"context"
"io"
"v2ray.com/core/app"
"v2ray.com/core/app/dns"
"v2ray.com/core/common"
"v2ray.com/core/common/buf"
"v2ray.com/core/common/dice"
"v2ray.com/core/common/errors"
"v2ray.com/core/common/log"
"v2ray.com/core/common/net"
"v2ray.com/core/common/retry"
"v2ray.com/core/common/signal"
"v2ray.com/core/proxy"
"v2ray.com/core/transport/internet"
"v2ray.com/core/transport/ray"
)
type Handler struct {
domainStrategy Config_DomainStrategy
timeout uint32
dns dns.Server
destOverride *DestinationOverride
}
func New(ctx context.Context, config *Config) (*Handler, error) {
space := app.SpaceFromContext(ctx)
if space == nil {
return nil, errors.New("Freedom: No space in context.")
}
f := &Handler{
domainStrategy: config.DomainStrategy,
timeout: config.Timeout,
destOverride: config.DestinationOverride,
}
space.OnInitialize(func() error {
if config.DomainStrategy == Config_USE_IP {
f.dns = dns.FromSpace(space)
if f.dns == nil {
return errors.New("Freedom: DNS server is not found in the space.")
}
}
return nil
})
return f, nil
}
// Private: Visible for testing.
func (v *Handler) ResolveIP(destination net.Destination) net.Destination {
if !destination.Address.Family().IsDomain() {
return destination
}
ips := v.dns.Get(destination.Address.Domain())
if len(ips) == 0 {
log.Info("Freedom: DNS returns nil answer. Keep domain as is.")
return destination
}
ip := ips[dice.Roll(len(ips))]
var newDest net.Destination
if destination.Network == net.Network_TCP {
newDest = net.TCPDestination(net.IPAddress(ip), destination.Port)
} else {
newDest = net.UDPDestination(net.IPAddress(ip), destination.Port)
}
log.Info("Freedom: Changing destination from ", destination, " to ", newDest)
return newDest
}
func (v *Handler) Process(ctx context.Context, outboundRay ray.OutboundRay) error {
destination := proxy.DestinationFromContext(ctx)
if v.destOverride != nil {
server := v.destOverride.Server
destination = net.Destination{
Network: destination.Network,
Address: server.Address.AsAddress(),
Port: net.Port(server.Port),
}
}
log.Info("Freedom: Opening connection to ", destination)
input := outboundRay.OutboundInput()
output := outboundRay.OutboundOutput()
var conn internet.Connection
if v.domainStrategy == Config_USE_IP && destination.Address.Family().IsDomain() {
destination = v.ResolveIP(destination)
}
dialer := proxy.DialerFromContext(ctx)
err := retry.ExponentialBackoff(5, 100).On(func() error {
rawConn, err := dialer.Dial(ctx, destination)
if err != nil {
return err
}
conn = rawConn
return nil
})
if err != nil {
log.Warning("Freedom: Failed to open connection to ", destination, ": ", err)
return err
}
defer conn.Close()
conn.SetReusable(false)
requestDone := signal.ExecuteAsync(func() error {
v2writer := buf.NewWriter(conn)
if err := buf.PipeUntilEOF(input, v2writer); err != nil {
return err
}
return nil
})
var reader io.Reader = conn
timeout := v.timeout
if destination.Network == net.Network_UDP {
timeout = 16
}
if timeout > 0 {
reader = net.NewTimeOutReader(timeout /* seconds */, conn)
}
responseDone := signal.ExecuteAsync(func() error {
defer output.Close()
v2reader := buf.NewReader(reader)
if err := buf.Pipe(v2reader, output); err != nil {
return err
}
return nil
})
if err := signal.ErrorOrFinish2(ctx, requestDone, responseDone); err != nil {
log.Info("Freedom: Connection ending with ", err)
input.CloseError()
output.CloseError()
return err
}
return nil
}
func init() {
common.Must(common.RegisterConfig((*Config)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
return New(ctx, config.(*Config))
}))
}