ooni-probe-cli/internal/netxlite/dnsovergetaddrinfo.go
Simone Basso da1c13e312
cleanup: remove UnderlyingNetworkLibrary and TProxy (#874)
* cleanup: remove UnderlyingNetworkLibrary and TProxy

While there, replace mixture of mocking and real connections inside
quicping with pure mocking of network connections.

Closes https://github.com/ooni/probe/issues/2224

* cleanup: we don't need a SimpleResolver now

This type was only used by UnderlyingNetworkLibrary and all the
rest of the code uses Resolver. So, let's avoid complexity by zapping
the SimpleResolver type and merging it inside Resolver.
2022-08-23 11:43:44 +02:00

126 lines
2.9 KiB
Go

package netxlite
//
// DNS over getaddrinfo: fake transport to allow us to observe
// lookups using getaddrinfo as a DNSTransport.
//
import (
"context"
"net"
"time"
"github.com/miekg/dns"
"github.com/ooni/probe-cli/v3/internal/model"
)
// dnsOverGetaddrinfoTransport is a DNSTransport using getaddrinfo.
type dnsOverGetaddrinfoTransport struct {
testableTimeout time.Duration
testableLookupHost func(ctx context.Context, domain string) ([]string, error)
}
var _ model.DNSTransport = &dnsOverGetaddrinfoTransport{}
func (txp *dnsOverGetaddrinfoTransport) RoundTrip(
ctx context.Context, query model.DNSQuery) (model.DNSResponse, error) {
if query.Type() != dns.TypeANY {
return nil, ErrNoDNSTransport
}
addrs, err := txp.lookup(ctx, query.Domain())
if err != nil {
return nil, err
}
resp := &dnsOverGetaddrinfoResponse{
addrs: addrs,
query: query,
}
return resp, nil
}
type dnsOverGetaddrinfoResponse struct {
addrs []string
query model.DNSQuery
}
func (txp *dnsOverGetaddrinfoTransport) lookup(
ctx context.Context, hostname string) ([]string, error) {
// This code forces adding a shorter timeout to the domain name
// resolutions when using the system resolver. We have seen cases
// in which such a timeout becomes too large. One such case is
// described in https://github.com/ooni/probe/issues/1726.
addrsch, errch := make(chan []string, 1), make(chan error, 1)
ctx, cancel := context.WithTimeout(ctx, txp.timeout())
defer cancel()
go func() {
addrs, err := txp.lookupfn()(ctx, hostname)
if err != nil {
errch <- err
return
}
addrsch <- addrs
}()
select {
case <-ctx.Done():
return nil, ctx.Err()
case addrs := <-addrsch:
return addrs, nil
case err := <-errch:
return nil, err
}
}
func (txp *dnsOverGetaddrinfoTransport) timeout() time.Duration {
if txp.testableTimeout > 0 {
return txp.testableTimeout
}
return 15 * time.Second
}
func (txp *dnsOverGetaddrinfoTransport) lookupfn() func(ctx context.Context, domain string) ([]string, error) {
if txp.testableLookupHost != nil {
return txp.testableLookupHost
}
return getaddrinfoLookupHost
}
func (txp *dnsOverGetaddrinfoTransport) RequiresPadding() bool {
return false
}
func (txp *dnsOverGetaddrinfoTransport) Network() string {
return getaddrinfoResolverNetwork()
}
func (txp *dnsOverGetaddrinfoTransport) Address() string {
return ""
}
func (txp *dnsOverGetaddrinfoTransport) CloseIdleConnections() {
// nothing
}
func (r *dnsOverGetaddrinfoResponse) Query() model.DNSQuery {
return r.query
}
func (r *dnsOverGetaddrinfoResponse) Bytes() []byte {
return nil
}
func (r *dnsOverGetaddrinfoResponse) Rcode() int {
return 0
}
func (r *dnsOverGetaddrinfoResponse) DecodeHTTPS() (*model.HTTPSSvc, error) {
return nil, ErrNoDNSTransport
}
func (r *dnsOverGetaddrinfoResponse) DecodeLookupHost() ([]string, error) {
return r.addrs, nil
}
func (r *dnsOverGetaddrinfoResponse) DecodeNS() ([]*net.NS, error) {
return nil, ErrNoDNSTransport
}