06ee0e55a9
* refactor(netx/dialer): hide implementation complexity This follows the blueprint of `module.Config` and `nodule.New` described at https://github.com/ooni/probe/issues/1591. * fix: ndt7 bug where we were not using the right resolver * fix(legacy/netx): clarify irrelevant implementation change * fix: improve comments * fix(hhfm): do not use dialer.New b/c it breaks it Unclear to me why this is happening. Still, improve upon the previous situation by adding a timeout. It does not seem a priority to look into this issue now.
72 lines
2.0 KiB
Go
72 lines
2.0 KiB
Go
package dialer
|
|
|
|
import (
|
|
"context"
|
|
"errors"
|
|
"net"
|
|
"strings"
|
|
|
|
"github.com/ooni/probe-cli/v3/internal/engine/netx/errorx"
|
|
)
|
|
|
|
// dnsDialer is a dialer that uses the configured Resolver to resolver a
|
|
// domain name to IP addresses, and the configured Dialer to connect.
|
|
type dnsDialer struct {
|
|
Dialer
|
|
Resolver Resolver
|
|
}
|
|
|
|
// DialContext implements Dialer.DialContext.
|
|
func (d *dnsDialer) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
|
|
onlyhost, onlyport, err := net.SplitHostPort(address)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
var addrs []string
|
|
addrs, err = d.lookupHost(ctx, onlyhost)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
var errorslist []error
|
|
for _, addr := range addrs {
|
|
target := net.JoinHostPort(addr, onlyport)
|
|
conn, err := d.Dialer.DialContext(ctx, network, target)
|
|
if err == nil {
|
|
return conn, nil
|
|
}
|
|
errorslist = append(errorslist, err)
|
|
}
|
|
return nil, ReduceErrors(errorslist)
|
|
}
|
|
|
|
// ReduceErrors finds a known error in a list of errors since it's probably most relevant.
|
|
func ReduceErrors(errorslist []error) error {
|
|
if len(errorslist) == 0 {
|
|
return nil
|
|
}
|
|
// If we have a known error, let's consider this the real error
|
|
// since it's probably most relevant. Otherwise let's return the
|
|
// first considering that (1) local resolvers likely will give
|
|
// us IPv4 first and (2) also our resolver does that. So, in case
|
|
// the user has no IPv6 connectivity, an IPv6 error is going to
|
|
// appear later in the list of errors.
|
|
for _, err := range errorslist {
|
|
var wrapper *errorx.ErrWrapper
|
|
if errors.As(err, &wrapper) && !strings.HasPrefix(
|
|
err.Error(), "unknown_failure",
|
|
) {
|
|
return err
|
|
}
|
|
}
|
|
// TODO(bassosimone): handle this case in a better way
|
|
return errorslist[0]
|
|
}
|
|
|
|
// lookupHost performs a domain name resolution.
|
|
func (d *dnsDialer) lookupHost(ctx context.Context, hostname string) ([]string, error) {
|
|
if net.ParseIP(hostname) != nil {
|
|
return []string{hostname}, nil
|
|
}
|
|
return d.Resolver.LookupHost(ctx, hostname)
|
|
}
|