1153850aca
While there, `.../internal/sessionresolver` => `.../sessionresolver` See https://github.com/ooni/probe/issues/2255
42 lines
1.6 KiB
Go
42 lines
1.6 KiB
Go
package sessionresolver
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//
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// Actual lookup code
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//
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import (
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"context"
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"time"
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"github.com/ooni/probe-cli/v3/internal/model"
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)
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// defaultTimeLimitedLookupTimeout is the default timeout the code should
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// pass to the timeLimitedLookup function.
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//
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// This algorithm is similar to Firefox using TRR2 mode. See:
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// https://wiki.mozilla.org/Trusted_Recursive_Resolver#DNS-over-HTTPS_Prefs_in_Firefox
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//
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// We use a higher timeout than Firefox's timeout (1.5s) to be on the safe side
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// and therefore see to use DoH more often.
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const defaultTimeLimitedLookupTimeout = 4 * time.Second
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// timeLimitedLookup performs a time-limited lookup using the given re.
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func timeLimitedLookup(ctx context.Context, re model.Resolver, hostname string) ([]string, error) {
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return timeLimitedLookupWithTimeout(ctx, re, hostname, defaultTimeLimitedLookupTimeout)
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}
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// timeLimitedLookupWithTimeout is like timeLimitedLookup but with explicit timeout.
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func timeLimitedLookupWithTimeout(ctx context.Context, re model.Resolver,
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hostname string, timeout time.Duration) ([]string, error) {
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// In https://github.com/ooni/probe-cli/pull/807, I modified this code to
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// run in a background goroutine and this resulted in a data race, see
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// https://github.com/ooni/probe/issues/2135#issuecomment-1149840579. While
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// I could not reproduce the data race in a simple way, the race itself
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// seems to happen inside the http3 package. For now, I am going to revert
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// the change causing the race and I'll investigate later.
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ctx, cancel := context.WithTimeout(ctx, timeout)
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defer cancel()
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return re.LookupHost(ctx, hostname)
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}
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