ooni-probe-cli/internal/netxlite/maybeproxy.go
Simone Basso 314c3c934d
refactor(session.go): replace engine/netx with netxlite (#767)
This diff replaces engine/netx code with netxlite code in
the engine/session.go file. To this end, we needed to move
some code from engine/netx to netxlite. While there, we
did review and improve the unit tests.

A notable change in this diff is (or seems to be) that in
engine/session.go we're not filtering for bogons anymore so
that, in principle, we could believe a resolver returning
to us bogon IP addresses for OONI services. However, I did
not bother with changing bogons filtering because the
sessionresolver package is already filtering for bogons,
so it is actually okay to avoid doing that again the
session.go code. See:

https://github.com/ooni/probe-cli/blob/v3.15.0-alpha.1/internal/engine/internal/sessionresolver/resolvermaker.go#L88

There are two reference issues for this cleanup:

1. https://github.com/ooni/probe/issues/2115

2. https://github.com/ooni/probe/issues/2121
2022-05-30 22:00:45 +02:00

71 lines
2.2 KiB
Go

package netxlite
import (
"context"
"errors"
"net"
"net/url"
"github.com/ooni/probe-cli/v3/internal/model"
"golang.org/x/net/proxy"
)
// MaybeProxyDialer is a dialer that may use a proxy. If the ProxyURL is not configured,
// this dialer is a passthrough for the next Dialer in chain. Otherwise, it will internally
// create a SOCKS5 dialer that will connect to the proxy using the underlying Dialer.
type MaybeProxyDialer struct {
Dialer model.Dialer
ProxyURL *url.URL
}
// NewMaybeProxyDialer creates a new NewMaybeProxyDialer.
func NewMaybeProxyDialer(dialer model.Dialer, proxyURL *url.URL) *MaybeProxyDialer {
return &MaybeProxyDialer{
Dialer: dialer,
ProxyURL: proxyURL,
}
}
var _ model.Dialer = &MaybeProxyDialer{}
// CloseIdleConnections implements Dialer.CloseIdleConnections.
func (d *MaybeProxyDialer) CloseIdleConnections() {
d.Dialer.CloseIdleConnections()
}
// ErrProxyUnsupportedScheme indicates we don't support a protocol scheme.
var ErrProxyUnsupportedScheme = errors.New("proxy: unsupported scheme")
// DialContext implements Dialer.DialContext.
func (d *MaybeProxyDialer) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
url := d.ProxyURL
if url == nil {
return d.Dialer.DialContext(ctx, network, address)
}
if url.Scheme != "socks5" {
return nil, ErrProxyUnsupportedScheme
}
// the code at proxy/socks5.go never fails; see https://git.io/JfJ4g
child, _ := proxy.SOCKS5(network, url.Host, nil, &proxyDialerWrapper{d.Dialer})
return d.dial(ctx, child, network, address)
}
func (d *MaybeProxyDialer) dial(
ctx context.Context, child proxy.Dialer, network, address string) (net.Conn, error) {
cd := child.(proxy.ContextDialer) // will work
return cd.DialContext(ctx, network, address)
}
// proxyDialerWrapper is required because SOCKS5 expects a Dialer.Dial type but internally
// it checks whether DialContext is available and prefers that. So, we need to use this
// structure to cast our inner Dialer the way in which SOCKS5 likes it.
//
// See https://git.io/JfJ4g.
type proxyDialerWrapper struct {
model.Dialer
}
func (d *proxyDialerWrapper) Dial(network, address string) (net.Conn, error) {
panic(errors.New("proxyDialerWrapper.Dial should not be called directly"))
}