c1b06a2d09
This diff has been extracted and adapted from 8848c8c516
The reason to prefer composition over embedding is that we want the
build to break if we add new methods to interfaces we define. If the build
does not break, we may forget about wrapping methods we should
actually be wrapping. I noticed this issue inside netxlite when I was working
on websteps-illustrated and I added support for NS and PTR queries.
See https://github.com/ooni/probe/issues/2096
While there, perform comprehensive netxlite code review
and apply minor changes and improve the docs.
98 lines
2.8 KiB
Go
98 lines
2.8 KiB
Go
package netxlite
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//
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// DNS-over-HTTPS transport
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//
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import (
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"bytes"
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"context"
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"errors"
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"net/http"
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"time"
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"github.com/ooni/probe-cli/v3/internal/engine/httpheader"
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"github.com/ooni/probe-cli/v3/internal/model"
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)
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// DNSOverHTTPSTransport is a DNS-over-HTTPS DNSTransport.
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type DNSOverHTTPSTransport struct {
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// Client is the MANDATORY http client to use.
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Client model.HTTPClient
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// URL is the MANDATORY URL of the DNS-over-HTTPS server.
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URL string
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// HostOverride is OPTIONAL and allows to override the
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// Host header sent in every request.
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HostOverride string
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}
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// NewDNSOverHTTPSTransport creates a new DNSOverHTTPSTransport instance.
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//
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// Arguments:
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//
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// - client in http.Client-like type (e.g., http.DefaultClient);
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//
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// - URL is the DoH resolver URL (e.g., https://1.1.1.1/dns-query).
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func NewDNSOverHTTPSTransport(client model.HTTPClient, URL string) *DNSOverHTTPSTransport {
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return NewDNSOverHTTPSTransportWithHostOverride(client, URL, "")
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}
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// NewDNSOverHTTPSTransportWithHostOverride creates a new DNSOverHTTPSTransport
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// with the given Host header override.
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func NewDNSOverHTTPSTransportWithHostOverride(
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client model.HTTPClient, URL, hostOverride string) *DNSOverHTTPSTransport {
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return &DNSOverHTTPSTransport{Client: client, URL: URL, HostOverride: hostOverride}
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}
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// RoundTrip sends a query and receives a reply.
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func (t *DNSOverHTTPSTransport) RoundTrip(ctx context.Context, query []byte) ([]byte, error) {
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ctx, cancel := context.WithTimeout(ctx, 45*time.Second)
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defer cancel()
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req, err := http.NewRequest("POST", t.URL, bytes.NewReader(query))
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if err != nil {
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return nil, err
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}
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req.Host = t.HostOverride
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req.Header.Set("user-agent", httpheader.UserAgent())
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req.Header.Set("content-type", "application/dns-message")
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var resp *http.Response
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resp, err = t.Client.Do(req.WithContext(ctx))
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if err != nil {
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return nil, err
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}
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defer resp.Body.Close()
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if resp.StatusCode != 200 {
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// TODO(bassosimone): we should map the status code to a
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// proper Error in the DNS context.
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return nil, errors.New("doh: server returned error")
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}
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if resp.Header.Get("content-type") != "application/dns-message" {
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return nil, errors.New("doh: invalid content-type")
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}
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return ReadAllContext(ctx, resp.Body)
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}
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// RequiresPadding returns true for DoH according to RFC8467.
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func (t *DNSOverHTTPSTransport) RequiresPadding() bool {
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return true
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}
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// Network returns the transport network, i.e., "doh".
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func (t *DNSOverHTTPSTransport) Network() string {
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return "doh"
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}
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// Address returns the URL we're using for the DoH server.
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func (t *DNSOverHTTPSTransport) Address() string {
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return t.URL
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}
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// CloseIdleConnections closes idle connections, if any.
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func (t *DNSOverHTTPSTransport) CloseIdleConnections() {
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t.Client.CloseIdleConnections()
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}
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var _ model.DNSTransport = &DNSOverHTTPSTransport{}
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