133 lines
4.1 KiB
Go
133 lines
4.1 KiB
Go
package tor
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import (
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"context"
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"errors"
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"net"
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"time"
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)
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// TODO: this interface and its implementations should ideally be moved
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// elsewhere as they are not Tor-specific.
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const (
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// DefaultConnTimeout is the maximum amount of time a dial will wait for
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// a connect to complete.
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DefaultConnTimeout time.Duration = time.Second * 120
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)
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// DialFunc is a type defines the signature of a dialer used by our Net
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// interface.
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type DialFunc func(net, addr string, timeout time.Duration) (net.Conn, error)
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// Net is an interface housing a Dial function and several DNS functions that
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// allows us to abstract the implementations of these functions over different
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// networks, e.g. clearnet, Tor net, etc.
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type Net interface {
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// Dial connects to the address on the named network.
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Dial(network, address string, timeout time.Duration) (net.Conn, error)
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// LookupHost performs DNS resolution on a given host and returns its
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// addresses.
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LookupHost(host string) ([]string, error)
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// LookupSRV tries to resolve an SRV query of the given service,
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// protocol, and domain name.
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LookupSRV(service, proto, name string,
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timeout time.Duration) (string, []*net.SRV, error)
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// ResolveTCPAddr resolves TCP addresses.
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ResolveTCPAddr(network, address string) (*net.TCPAddr, error)
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}
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// ClearNet is an implementation of the Net interface that defines behaviour
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// for regular network connections.
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type ClearNet struct{}
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// Dial on the regular network uses net.Dial
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func (r *ClearNet) Dial(
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network, address string, timeout time.Duration) (net.Conn, error) {
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return net.DialTimeout(network, address, timeout)
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}
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// LookupHost for regular network uses the net.LookupHost function
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func (r *ClearNet) LookupHost(host string) ([]string, error) {
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return net.LookupHost(host)
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}
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// LookupSRV for regular network uses net.LookupSRV function
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func (r *ClearNet) LookupSRV(service, proto, name string,
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timeout time.Duration) (string, []*net.SRV, error) {
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// Create a context with a timeout value.
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ctxt, cancel := context.WithTimeout(context.Background(), timeout)
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defer cancel()
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return net.DefaultResolver.LookupSRV(ctxt, service, proto, name)
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}
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// ResolveTCPAddr for regular network uses net.ResolveTCPAddr function
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func (r *ClearNet) ResolveTCPAddr(network, address string) (*net.TCPAddr, error) {
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return net.ResolveTCPAddr(network, address)
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}
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// ProxyNet is an implementation of the Net interface that defines behaviour
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// for Tor network connections.
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type ProxyNet struct {
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// SOCKS is the host:port which Tor's exposed SOCKS5 proxy is listening
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// on.
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SOCKS string
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// DNS is the host:port of the DNS server for Tor to use for SRV
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// queries.
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DNS string
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// StreamIsolation is a bool that determines if we should force the
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// creation of a new circuit for this connection. If true, then this
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// means that our traffic may be harder to correlate as each connection
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// will now use a distinct circuit.
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StreamIsolation bool
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}
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// Dial uses the Tor Dial function in order to establish connections through
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// Tor. Since Tor only supports TCP connections, only TCP networks are allowed.
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func (p *ProxyNet) Dial(network, address string,
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timeout time.Duration) (net.Conn, error) {
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switch network {
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case "tcp", "tcp4", "tcp6":
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default:
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return nil, errors.New("cannot dial non-tcp network via Tor")
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}
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return Dial(address, p.SOCKS, p.StreamIsolation, timeout)
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}
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// LookupHost uses the Tor LookupHost function in order to resolve hosts over
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// Tor.
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func (p *ProxyNet) LookupHost(host string) ([]string, error) {
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return LookupHost(host, p.SOCKS)
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}
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// LookupSRV uses the Tor LookupSRV function in order to resolve SRV DNS queries
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// over Tor.
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func (p *ProxyNet) LookupSRV(service, proto,
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name string, timeout time.Duration) (string, []*net.SRV, error) {
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return LookupSRV(
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service, proto, name, p.SOCKS, p.DNS,
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p.StreamIsolation, timeout,
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)
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}
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// ResolveTCPAddr uses the Tor ResolveTCPAddr function in order to resolve TCP
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// addresses over Tor.
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func (p *ProxyNet) ResolveTCPAddr(network, address string) (*net.TCPAddr, error) {
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switch network {
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case "tcp", "tcp4", "tcp6":
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default:
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return nil, errors.New("cannot dial non-tcp network via Tor")
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}
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return ResolveTCPAddr(address, p.SOCKS)
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}
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