cc24f28b9d
* feat(netxlite): support extracting the CNAME Closes https://github.com/ooni/probe/issues/2225 * fix(netxlite): attempt to increase coverage and improve tests 1. dnsovergetaddrinfo: specify the behavior of a DNSResponse returned by this file to make it line with normal responses and write unit tests to make sure we adhere to expectations; 2. dnsoverudp: make sure we wait to deferred responses also w/o a custom context and post on a private channel and test that; 3. utls: recognize that we can actually write a test for NetConn and what needs to change when we'll use go1.19 by default will just be a cast that at that point can be removed.
140 lines
3.3 KiB
Go
140 lines
3.3 KiB
Go
package netxlite
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//
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// DNS over getaddrinfo: fake transport to allow us to observe
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// lookups using getaddrinfo as a DNSTransport.
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//
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import (
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"context"
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"net"
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"time"
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"github.com/miekg/dns"
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"github.com/ooni/probe-cli/v3/internal/model"
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"github.com/ooni/probe-cli/v3/internal/runtimex"
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)
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// dnsOverGetaddrinfoTransport is a DNSTransport using getaddrinfo.
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type dnsOverGetaddrinfoTransport struct {
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testableTimeout time.Duration
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testableLookupHost func(ctx context.Context, domain string) ([]string, error)
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}
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var _ model.DNSTransport = &dnsOverGetaddrinfoTransport{}
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func (txp *dnsOverGetaddrinfoTransport) RoundTrip(
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ctx context.Context, query model.DNSQuery) (model.DNSResponse, error) {
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if query.Type() != dns.TypeANY {
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return nil, ErrNoDNSTransport
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}
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addrs, err := txp.lookup(ctx, query.Domain())
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if err != nil {
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return nil, err
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}
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resp := &dnsOverGetaddrinfoResponse{
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addrs: addrs,
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cname: "", // TODO: implement this functionality
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query: query,
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}
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return resp, nil
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}
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type dnsOverGetaddrinfoResponse struct {
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addrs []string
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cname string
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query model.DNSQuery
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}
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func (txp *dnsOverGetaddrinfoTransport) lookup(
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ctx context.Context, hostname string) ([]string, error) {
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// This code forces adding a shorter timeout to the domain name
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// resolutions when using the system resolver. We have seen cases
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// in which such a timeout becomes too large. One such case is
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// described in https://github.com/ooni/probe/issues/1726.
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addrsch, errch := make(chan []string, 1), make(chan error, 1)
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ctx, cancel := context.WithTimeout(ctx, txp.timeout())
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defer cancel()
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go func() {
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addrs, err := txp.lookupfn()(ctx, hostname)
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if err != nil {
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errch <- err
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return
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}
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addrsch <- addrs
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}()
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select {
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case <-ctx.Done():
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return nil, ctx.Err()
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case addrs := <-addrsch:
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return addrs, nil
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case err := <-errch:
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return nil, err
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}
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}
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func (txp *dnsOverGetaddrinfoTransport) timeout() time.Duration {
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if txp.testableTimeout > 0 {
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return txp.testableTimeout
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}
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return 15 * time.Second
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}
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func (txp *dnsOverGetaddrinfoTransport) lookupfn() func(ctx context.Context, domain string) ([]string, error) {
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if txp.testableLookupHost != nil {
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return txp.testableLookupHost
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}
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return getaddrinfoLookupHost
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}
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func (txp *dnsOverGetaddrinfoTransport) RequiresPadding() bool {
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return false
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}
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func (txp *dnsOverGetaddrinfoTransport) Network() string {
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return getaddrinfoResolverNetwork()
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}
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func (txp *dnsOverGetaddrinfoTransport) Address() string {
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return ""
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}
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func (txp *dnsOverGetaddrinfoTransport) CloseIdleConnections() {
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// nothing
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}
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func (r *dnsOverGetaddrinfoResponse) Query() model.DNSQuery {
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runtimex.PanicIfNil(r.query, "dnsOverGetaddrinfoResponse with nil query")
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return r.query
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}
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func (r *dnsOverGetaddrinfoResponse) Bytes() []byte {
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return nil
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}
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func (r *dnsOverGetaddrinfoResponse) Rcode() int {
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return 0
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}
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func (r *dnsOverGetaddrinfoResponse) DecodeHTTPS() (*model.HTTPSSvc, error) {
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return nil, ErrNoDNSTransport
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}
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func (r *dnsOverGetaddrinfoResponse) DecodeLookupHost() ([]string, error) {
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if len(r.addrs) <= 0 {
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return nil, ErrOODNSNoAnswer
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}
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return r.addrs, nil
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}
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func (r *dnsOverGetaddrinfoResponse) DecodeNS() ([]*net.NS, error) {
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return nil, ErrNoDNSTransport
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}
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func (r *dnsOverGetaddrinfoResponse) DecodeCNAME() (string, error) {
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if r.cname == "" {
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return "", ErrOODNSNoAnswer
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}
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return r.cname, nil
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}
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