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asaur/listener.go

140 lines
3.7 KiB
Go

// listener.go - Tor backed net.Listener.
//
// To the extent possible under law, Yawning Angel and Ivan Markin
// waived all copyright and related or neighboring rights to bulb, using
// the creative commons "cc0" public domain dedication. See LICENSE or
// <http://creativecommons.org/publicdomain/zero/1.0/> for full details.
package asaur
import (
"crypto"
goodrand "crypto/rand"
"encoding/binary"
"fmt"
"golang.org/x/crypto/sha3"
"log"
"net"
"strconv"
)
type onionAddr struct {
info *OnionInfo
port uint16
}
func (a *onionAddr) Network() string {
return "tcp"
}
func (a *onionAddr) String() string {
return fmt.Sprintf("%s.onion:%d", a.info.OnionID, a.port)
}
type onionListener struct {
addr *onionAddr
ctrlConn *Conn
listener net.Listener
}
func (l *onionListener) Accept() (net.Conn, error) {
return l.listener.Accept()
}
func (l *onionListener) Close() (err error) {
if err = l.listener.Close(); err == nil {
// Only delete the onion once.
err = l.ctrlConn.DeleteOnion(l.addr.info.OnionID)
}
return err
}
func (l *onionListener) Addr() net.Addr {
return l.addr
}
// NewListener returns a net.Listener backed by an Onion Service using configuration
// config, optionally having Tor generate an ephemeral private key (config is nil or
// config.PrivateKey is nil).
// All of virtual ports specified in vports will be mapped to the port to which
// the underlying TCP listener binded. PortSpecs in config will be ignored since
// there is only one mapping for a vports set is possible.
// [DEPRECATED] generate a random port to listen on (this is for backwards compatibility)
func (c *Conn) NewListener(config *NewOnionConfig, vports ...uint16) (net.Listener, error) {
return c.RecoverListener(config, "", vports...)
}
func (c *Conn) RecoverListener(config *NewOnionConfig, onion string, vports ...uint16) (net.Listener, error) {
var cfg NewOnionConfig
if config == nil {
cfg = NewOnionConfig{
DiscardPK: true,
}
} else {
cfg = *config
}
var port int
if onion == "" { // generate a random port for ephemeral programs
seedbytes := make([]byte, 2)
goodrand.Read(seedbytes)
port = int(binary.LittleEndian.Uint16(seedbytes))
} else { // generate a deterministic port for resumptive programs
seedbytes := sha3.New224().Sum([]byte(onion))
port = int(seedbytes[0]) + (int(seedbytes[1]) << 8)
}
if port < 1024 { // this is not uniformly random, but we don't need it to be
port += 1024
}
log.Printf("using local port: %d\n", port)
var loopbackAddr = "127.0.0.1:" + strconv.Itoa(port)
// Listen on the loopback interface.
tcpListener, err := net.Listen("tcp4", loopbackAddr)
if err != nil {
return nil, err
}
tAddr, ok := tcpListener.Addr().(*net.TCPAddr)
if !ok {
tcpListener.Close()
return nil, newProtocolError("failed to extract local port")
}
if len(vports) < 1 {
return nil, newProtocolError("no virtual ports specified")
}
targetPortStr := strconv.FormatUint((uint64)(tAddr.Port), 10)
var portSpecs []OnionPortSpec
for _, vport := range vports {
portSpecs = append(portSpecs, OnionPortSpec{
VirtPort: vport,
Target: targetPortStr,
})
}
cfg.PortSpecs = portSpecs
// Create the onion.
oi, err := c.NewOnion(&cfg, false)
if err != nil {
tcpListener.Close()
return nil, err
}
oa := &onionAddr{info: oi, port: vports[0]}
ol := &onionListener{addr: oa, ctrlConn: c, listener: tcpListener}
return ol, nil
}
// [DEPRECATED] Listener returns a net.Listener backed by an Onion Service.
func (c *Conn) Listener(port uint16, key crypto.PrivateKey) (net.Listener, error) {
cfg := &NewOnionConfig{}
if key != nil {
cfg.PrivateKey = key
cfg.DiscardPK = false
} else {
cfg.DiscardPK = true
}
return c.NewListener(cfg, port)
}