Propagate settings to Proxy

internal/cli/run_proxy.go

 		return fmt.Errorf("cannot build ip allowlist: %w", err)
 	}
 
+	doppelGangerURLs := make([]string, len(conf.Defense.Doppelganger.URLs))
+	for i, v := range conf.Defense.Doppelganger.URLs {
+		doppelGangerURLs[i] = v.String()
+	}
+
 	opts := mtglib.ProxyOpts{
 		Logger:          logger,
 		Network:         ntw,
 
 		AllowFallbackOnUnknownDC: conf.AllowFallbackOnUnknownDC.Get(false),
 		TolerateTimeSkewness:     conf.TolerateTimeSkewness.Value,
+
+		DoppelGangerURLs:    doppelGangerURLs,
+		DoppelGangerPerRaid: conf.Defense.Doppelganger.Repeats.Get(mtglib.DoppelGangerPerRaid),
+		DoppelGangerEach:    conf.Defense.Doppelganger.UpdateEach.Get(mtglib.DoppelGangerEach),
 	}
 
 	proxy, err := mtglib.NewProxy(opts)

mtglib/init.go

 	// reads from Telegram after which connection will be terminated. This is
 	// required to abort stale connections.
 	TCPRelayReadTimeout = 20 * time.Second
+
+	// DoppelGangerPerRaid defines a number of requests to each URL
+	// per raid.
+	DoppelGangerPerRaid = 10
+
+	// DoppelGangerEach defines a time period between each crawl attempt.
+	DoppelGangerEach = 6 * time.Hour
 )
 
 // Network defines a knowledge how to work with a network. It may sound fun but

mtglib/proxy.go

 	p.streamWaitGroup.Wait()
 	p.workerPool.Release()
 	p.configUpdater.Wait()
+	p.doppelGanger.Shutdown()
 
 	p.allowlist.Shutdown()
 	p.blocklist.Shutdown()
 		tolerateTimeSkewness:     opts.getTolerateTimeSkewness(),
 		allowFallbackOnUnknownDC: opts.AllowFallbackOnUnknownDC,
 		telegram:                 tg,
+		doppelGanger: doppel.NewGanger(
+			ctx,
+			opts.Network,
+			logger.Named("doppelganger"),
+			opts.DoppelGangerEach,
+			int(opts.DoppelGangerPerRaid),
+			opts.DoppelGangerURLs,
+		),
 		configUpdater: dc.NewPublicConfigUpdater(
 			tg,
 			updatersLogger.Named("public-config"),
 		domainFrontingProxyProtocol: opts.DomainFrontingProxyProtocol,
 	}
 
+	proxy.doppelGanger.Run()
+
 	if opts.AutoUpdate {
 		proxy.configUpdater.Run(ctx, dc.PublicConfigUpdateURLv4, "tcp4")
 		proxy.configUpdater.Run(ctx, dc.PublicConfigUpdateURLv6, "tcp6")

mtglib/proxy_opts.go

 	//
 	// OBSOLETE and DEPRECATED. Ignored.
 	DCOverrides map[int][]string
+
+	// DoppelGangerURLs is a list of URLs that should be crawled by
+	// mtg to calculate parameters for statistical distribution of a
+	// traffic for fronting domains. If nothing is given, then predefined
+	// statistics is going to be used.
+	DoppelGangerURLs []string
+
+	// DoppelGangerPerRaid defines how many time each URL from
+	// DoppelGangerURLs list should be crawled per raid. We recommend to
+	// have this number ~10.
+	DoppelGangerPerRaid uint
+
+	// DoppelGangerEach defines a time period between each raid. We recommend
+	// to use hours here.
+	DoppelGangerEach time.Duration
 }
 
 func (p ProxyOpts) valid() error {