0fdc9cafb5
* fix(all): introduce and use iox.ReadAllContext This improvement over the ioutil.ReadAll utility returns early if the context expires. This enables us to unblock stuck code in case there's censorship confounding the TCP stack. See https://github.com/ooni/probe/issues/1417. Compared to the functionality postulated in the above mentioned issue, I choose to be more generic and separate limiting the maximum body size (not implemented here) from using the context to return early when reading a body (or any other reader). After implementing iox.ReadAllContext, I made sure we always use it everywhere in the tree instead of ioutil.ReadAll. This includes many parts of the codebase where in theory we don't need iox.ReadAllContext. Though, changing all the places makes checking whether we're not using ioutil.ReadAll where we should not be using it easy: `git grep` should return no lines. * Update internal/iox/iox_test.go * fix(ndt7): treat context errors as non-errors The rationale is explained by the comment documenting reduceErr. * Update internal/engine/experiment/ndt7/download.go
78 lines
2.3 KiB
Go
78 lines
2.3 KiB
Go
package resolver
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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/iox"
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)
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// DNSOverHTTPS is a DNS over HTTPS RoundTripper. Requests are submitted over
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// an HTTP/HTTPS channel provided by URL using the Do function.
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type DNSOverHTTPS struct {
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Do func(req *http.Request) (*http.Response, error)
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URL string
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HostOverride string
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}
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// NewDNSOverHTTPS creates a new DNSOverHTTP instance from the
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// specified http.Client and URL, as a convenience.
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func NewDNSOverHTTPS(client *http.Client, URL string) DNSOverHTTPS {
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return NewDNSOverHTTPSWithHostOverride(client, URL, "")
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}
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// NewDNSOverHTTPSWithHostOverride is like NewDNSOverHTTPS except that
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// it's creating a resolver where we use the specified host.
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func NewDNSOverHTTPSWithHostOverride(client *http.Client, URL, hostOverride string) DNSOverHTTPS {
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return DNSOverHTTPS{Do: client.Do, URL: URL, HostOverride: hostOverride}
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}
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// RoundTrip implements RoundTripper.RoundTrip.
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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.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 iox.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 (e.g., doh, dot)
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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 upstream server address.
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func (t DNSOverHTTPS) Address() string {
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return t.URL
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}
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var _ RoundTripper = DNSOverHTTPS{}
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