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freedom.go
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freedom.go
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package freedom
//go:generate errorgen
import (
"context"
"time"
"v2ray.com/core"
"v2ray.com/core/common"
"v2ray.com/core/common/buf"
"v2ray.com/core/common/dice"
"v2ray.com/core/common/net"
"v2ray.com/core/common/retry"
"v2ray.com/core/common/session"
"v2ray.com/core/common/signal"
"v2ray.com/core/common/task"
"v2ray.com/core/proxy"
"v2ray.com/core/transport/internet"
)
// Handler handles Freedom connections.
type Handler struct {
policyManager core.PolicyManager
dns core.DNSClient
config Config
}
// New creates a new Freedom handler.
func New(ctx context.Context, config *Config) (*Handler, error) {
v := core.MustFromContext(ctx)
f := &Handler{
config: *config,
policyManager: v.PolicyManager(),
dns: v.DNSClient(),
}
return f, nil
}
func (h *Handler) policy() core.Policy {
p := h.policyManager.ForLevel(h.config.UserLevel)
if h.config.Timeout > 0 && h.config.UserLevel == 0 {
p.Timeouts.ConnectionIdle = time.Duration(h.config.Timeout) * time.Second
}
return p
}
func (h *Handler) resolveIP(ctx context.Context, domain string) net.Address {
if resolver, ok := proxy.ResolvedIPsFromContext(ctx); ok {
ips := resolver.Resolve()
if len(ips) == 0 {
return nil
}
return ips[dice.Roll(len(ips))]
}
ips, err := h.dns.LookupIP(domain)
if err != nil {
newError("failed to get IP address for domain ", domain).Base(err).WriteToLog(session.ExportIDToError(ctx))
}
if len(ips) == 0 {
return nil
}
return net.IPAddress(ips[dice.Roll(len(ips))])
}
func isValidAddress(addr *net.IPOrDomain) bool {
if addr == nil {
return false
}
a := addr.AsAddress()
return a != net.AnyIP
}
// Process implements proxy.Outbound.
func (h *Handler) Process(ctx context.Context, link *core.Link, dialer proxy.Dialer) error {
outbound := session.OutboundFromContext(ctx)
if outbound == nil || !outbound.Target.IsValid() {
return newError("target not specified.")
}
destination := outbound.Target
if h.config.DestinationOverride != nil {
server := h.config.DestinationOverride.Server
if isValidAddress(server.Address) {
destination.Address = server.Address.AsAddress()
}
if server.Port != 0 {
destination.Port = net.Port(server.Port)
}
}
newError("opening connection to ", destination).WriteToLog(session.ExportIDToError(ctx))
input := link.Reader
output := link.Writer
var conn internet.Connection
err := retry.ExponentialBackoff(5, 100).On(func() error {
dialDest := destination
if h.config.DomainStrategy == Config_USE_IP && dialDest.Address.Family().IsDomain() {
ip := h.resolveIP(ctx, dialDest.Address.Domain())
if ip != nil {
dialDest = net.Destination{
Network: dialDest.Network,
Address: ip,
Port: dialDest.Port,
}
newError("dialing to to ", dialDest).WriteToLog(session.ExportIDToError(ctx))
}
}
rawConn, err := dialer.Dial(ctx, dialDest)
if err != nil {
return err
}
conn = rawConn
return nil
})
if err != nil {
return newError("failed to open connection to ", destination).Base(err)
}
defer conn.Close() // nolint: errcheck
plcy := h.policy()
ctx, cancel := context.WithCancel(ctx)
timer := signal.CancelAfterInactivity(ctx, cancel, plcy.Timeouts.ConnectionIdle)
requestDone := func() error {
defer timer.SetTimeout(plcy.Timeouts.DownlinkOnly)
var writer buf.Writer
if destination.Network == net.Network_TCP {
writer = buf.NewWriter(conn)
} else {
writer = &buf.SequentialWriter{Writer: conn}
}
if err := buf.Copy(input, writer, buf.UpdateActivity(timer)); err != nil {
return newError("failed to process request").Base(err)
}
return nil
}
responseDone := func() error {
defer timer.SetTimeout(plcy.Timeouts.UplinkOnly)
if err := buf.Copy(buf.NewReader(conn), output, buf.UpdateActivity(timer)); err != nil {
return newError("failed to process response").Base(err)
}
return nil
}
if err := task.Run(task.WithContext(ctx), task.Parallel(requestDone, task.Single(responseDone, task.OnSuccess(task.Close(output)))))(); err != nil {
return newError("connection ends").Base(err)
}
return nil
}
func init() {
common.Must(common.RegisterConfig((*Config)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
return New(ctx, config.(*Config))
}))
}