Pull request 1927: 6006-use-address-processor

Updates #6006.

Squashed commit of the following:

commit ac27db95c12858b6ef182a0bd4acebab67a23993
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Tue Jul 18 15:47:17 2023 +0300

    all: imp code

commit 3936288512bfc2d44902ead6ab1bb5711f92b73c
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Jul 17 19:23:46 2023 +0300

    all: imp client resolving

internal/dnsforward/config.go

@@ -13,6 +13,7 @@ import (
 	"github.com/AdguardTeam/AdGuardHome/internal/aghalg"
 	"github.com/AdguardTeam/AdGuardHome/internal/aghhttp"
 	"github.com/AdguardTeam/AdGuardHome/internal/aghtls"
+	"github.com/AdguardTeam/AdGuardHome/internal/client"
 	"github.com/AdguardTeam/AdGuardHome/internal/filtering"
 	"github.com/AdguardTeam/dnsproxy/proxy"
 	"github.com/AdguardTeam/golibs/errors"
@@ -270,7 +271,13 @@ type ServerConfig struct {
 	UDPListenAddrs []*net.UDPAddr        // UDP listen address
 	TCPListenAddrs []*net.TCPAddr        // TCP listen address
 	UpstreamConfig *proxy.UpstreamConfig // Upstream DNS servers config
-	OnDNSRequest   func(d *proxy.DNSContext)
+
+	// AddrProcConf defines the configuration for the client IP processor.
+	// If nil, [client.EmptyAddrProc] is used.
+	//
+	// TODO(a.garipov): The use of [client.EmptyAddrProc] is a crutch for tests.
+	// Remove that.
+	AddrProcConf *client.DefaultAddrProcConfig
 
 	FilteringConfig
 	TLSConfig
@@ -298,9 +305,6 @@ type ServerConfig struct {
 	// DNS64Prefixes is a slice of NAT64 prefixes to be used for DNS64.
 	DNS64Prefixes []netip.Prefix
 
-	// ResolveClients signals if the RDNS should resolve clients' addresses.
-	ResolveClients bool
-
 	// UsePrivateRDNS defines if the PTR requests for unknown addresses from
 	// locally-served networks should be resolved via private PTR resolvers.
 	UsePrivateRDNS bool