b2b1a4b2f1
Part of https://github.com/ooni/probe-cli/pull/506. In parallel with tutorials, we also need to make sure we have good documentation.
99 lines
2.7 KiB
Go
99 lines
2.7 KiB
Go
package netxlite
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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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)
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// HTTPClient is an http.Client-like interface.
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type HTTPClient interface {
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Do(req *http.Request) (*http.Response, error)
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CloseIdleConnections()
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}
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// DNSOverHTTPS is a DNS-over-HTTPS DNSTransport.
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type DNSOverHTTPS struct {
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// Client is the MANDATORY http client to use.
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Client 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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// NewDNSOverHTTPS creates a new DNSOverHTTPS 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 NewDNSOverHTTPS(client HTTPClient, URL string) *DNSOverHTTPS {
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return NewDNSOverHTTPSWithHostOverride(client, URL, "")
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}
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// NewDNSOverHTTPSWithHostOverride creates a new DNSOverHTTPS
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// with the given Host header override.
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func NewDNSOverHTTPSWithHostOverride(
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client HTTPClient, URL, hostOverride string) *DNSOverHTTPS {
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return &DNSOverHTTPS{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 *DNSOverHTTPS) 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 *DNSOverHTTPS) 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 *DNSOverHTTPS) 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 *DNSOverHTTPS) 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 *DNSOverHTTPS) CloseIdleConnections() {
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t.Client.CloseIdleConnections()
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}
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var _ DNSTransport = &DNSOverHTTPS{}
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