28 lines
936 B
Go
28 lines
936 B
Go
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package sessionresolver
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import (
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"context"
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"time"
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)
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// childResolver is the DNS client that this package uses
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// to perform individual domain name resolutions.
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type childResolver interface {
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// LookupHost performs a DNS lookup.
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LookupHost(ctx context.Context, domain string) ([]string, error)
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// CloseIdleConnections closes idle connections.
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CloseIdleConnections()
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}
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// timeLimitedLookup performs a time-limited lookup using the given re.
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func (r *Resolver) timeLimitedLookup(ctx context.Context, re childResolver, hostname string) ([]string, error) {
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// Algorithm similar to Firefox TRR2 mode. See:
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// https://wiki.mozilla.org/Trusted_Recursive_Resolver#DNS-over-HTTPS_Prefs_in_Firefox
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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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ctx, cancel := context.WithTimeout(ctx, 4*time.Second)
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defer cancel()
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return re.LookupHost(ctx, hostname)
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}
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