535a5d3e00
In https://github.com/ooni/probe-cli/pull/832's initial diff, I mentioned it would be cool to flatten oohelperd's hier. I'm doing this now, and just for the master branch. This diff is mostly a mechanical refactoring with very light and apparently rather safe manual changes.
85 lines
2.3 KiB
Go
85 lines
2.3 KiB
Go
package main
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//
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// DNS measurements
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//
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import (
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"context"
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"sync"
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"github.com/ooni/probe-cli/v3/internal/engine/experiment/webconnectivity"
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"github.com/ooni/probe-cli/v3/internal/model"
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"github.com/ooni/probe-cli/v3/internal/netxlite"
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"github.com/ooni/probe-cli/v3/internal/tracex"
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)
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// newfailure is a convenience shortcut to save typing
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var newfailure = tracex.NewFailure
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// ctrlDNSResult is the result of the DNS check performed by
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// the Web Connectivity test helper.
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type ctrlDNSResult = webconnectivity.ControlDNSResult
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// dnsConfig configures the DNS check.
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type dnsConfig struct {
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// Domain is the MANDATORY domain to resolve.
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Domain string
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// NewResolver is the MANDATORY factory to create a new resolver.
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NewResolver func() model.Resolver
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// Out is the channel where we publish the results.
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Out chan ctrlDNSResult
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// Wg allows to synchronize with the parent.
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Wg *sync.WaitGroup
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}
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// dnsDo performs the DNS check.
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func dnsDo(ctx context.Context, config *dnsConfig) {
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defer config.Wg.Done()
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reso := config.NewResolver()
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defer reso.CloseIdleConnections()
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addrs, err := reso.LookupHost(ctx, config.Domain)
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if addrs == nil {
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addrs = []string{} // fix: the old test helper did that
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}
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failure := dnsMapFailure(newfailure(err))
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config.Out <- ctrlDNSResult{Failure: failure, Addrs: addrs}
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}
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// dnsMapFailure attempts to map netxlite failures to the strings
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// used by the original OONI test helper.
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//
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// See https://github.com/ooni/backend/blob/6ec4fda5b18/oonib/testhelpers/http_helpers.py#L430
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func dnsMapFailure(failure *string) *string {
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switch failure {
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case nil:
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return nil
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default:
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switch *failure {
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case netxlite.FailureDNSNXDOMAINError:
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// We have a name for this string because dnsanalysis.go is
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// already checking for this specific error string.
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s := webconnectivity.DNSNameError
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return &s
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case netxlite.FailureDNSNoAnswer:
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// In this case the legacy TH would produce an empty
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// reply that is not attached to any error.
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//
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// See https://github.com/ooni/probe/issues/1707#issuecomment-944322725
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return nil
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case netxlite.FailureDNSNonRecoverableFailure,
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netxlite.FailureDNSRefusedError,
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netxlite.FailureDNSServerMisbehaving,
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netxlite.FailureDNSTemporaryFailure:
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s := "dns_server_failure"
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return &s
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default:
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s := "unknown_error"
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return &s
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}
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}
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}
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