ooni-probe-cli/internal/engine/geolocate/iplookup.go
Simone Basso beba543b98
cleanup: use NewHTTPTransportWithResolver more often (#808)
We can simplify code in a bunch of places using a useful factory.

Part of https://github.com/ooni/probe/issues/2121.
2022-06-08 15:13:01 +02:00

115 lines
2.7 KiB
Go

package geolocate
import (
"context"
"errors"
"fmt"
"math/rand"
"net"
"net/http"
"time"
"github.com/ooni/probe-cli/v3/internal/model"
"github.com/ooni/probe-cli/v3/internal/multierror"
"github.com/ooni/probe-cli/v3/internal/netxlite"
)
var (
// ErrAllIPLookuppersFailed indicates that we failed with looking
// up the probe IP for with all the lookuppers that we tried.
ErrAllIPLookuppersFailed = errors.New("all IP lookuppers failed")
// ErrInvalidIPAddress indicates that the code returned to us a
// string that actually isn't a valid IP address.
ErrInvalidIPAddress = errors.New("lookupper did not return a valid IP")
)
type lookupFunc func(
ctx context.Context, client *http.Client,
logger model.Logger, userAgent string,
) (string, error)
type method struct {
name string
fn lookupFunc
}
var (
methods = []method{
{
name: "cloudflare",
fn: cloudflareIPLookup,
},
{
name: "stun_ekiga",
fn: stunEkigaIPLookup,
},
{
name: "stun_google",
fn: stunGoogleIPLookup,
},
{
name: "ubuntu",
fn: ubuntuIPLookup,
},
}
)
type ipLookupClient struct {
// Resolver is the resolver to use for HTTP.
Resolver model.Resolver
// Logger is the logger to use
Logger model.Logger
// UserAgent is the user agent to use
UserAgent string
}
func makeSlice() []method {
r := rand.New(rand.NewSource(time.Now().UnixNano()))
ret := make([]method, len(methods))
perm := r.Perm(len(methods))
for idx, randIdx := range perm {
ret[idx] = methods[randIdx]
}
return ret
}
func (c ipLookupClient) doWithCustomFunc(
ctx context.Context, fn lookupFunc,
) (string, error) {
// Reliability fix: let these mechanisms timeout earlier.
const timeout = 7 * time.Second
ctx, cancel := context.WithTimeout(ctx, timeout)
defer cancel()
// Implementation note: we MUST use an HTTP client that we're
// sure IS NOT using any proxy. To this end, we construct a
// client ourself that we know is not proxied.
txp := netxlite.NewHTTPTransportWithResolver(c.Logger, c.Resolver)
clnt := &http.Client{Transport: txp}
defer clnt.CloseIdleConnections()
ip, err := fn(ctx, clnt, c.Logger, c.UserAgent)
if err != nil {
return DefaultProbeIP, err
}
if net.ParseIP(ip) == nil {
return DefaultProbeIP, fmt.Errorf("%w: %s", ErrInvalidIPAddress, ip)
}
c.Logger.Debugf("iplookup: IP: %s", ip)
return ip, nil
}
func (c ipLookupClient) LookupProbeIP(ctx context.Context) (string, error) {
union := multierror.New(ErrAllIPLookuppersFailed)
for _, method := range makeSlice() {
c.Logger.Infof("iplookup: using %s", method.name)
ip, err := c.doWithCustomFunc(ctx, method.fn)
if err == nil {
return ip, nil
}
union.Add(err)
}
return DefaultProbeIP, union
}