Pull request 2057: dnsforward: imp clientid log

Updates #6371.

Squashed commit of the following:

commit 0461266
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Tue Oct 31 21:38:20 2023 +0300

    dnsforward: imp clientid log

internal/dnsforward/clientid.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/AdguardTeam/dnsproxy/proxy"
 	"github.com/AdguardTeam/golibs/errors"
+	"github.com/AdguardTeam/golibs/log"
 	"github.com/AdguardTeam/golibs/netutil"
 	"github.com/quic-go/quic-go"
 )
@@ -151,6 +152,8 @@ func (s *Server) clientIDFromDNSContext(pctx *proxy.DNSContext) (clientID string
 // DNS-over-HTTPS requests, it will return the hostname part of the Host header
 // if there is one.
 func clientServerName(pctx *proxy.DNSContext, proto proxy.Proto) (srvName string, err error) {
+	from := "tls conn"
+
 	switch proto {
 	case proxy.ProtoHTTPS:
 		r := pctx.HTTPRequest
@@ -164,6 +167,7 @@ func clientServerName(pctx *proxy.DNSContext, proto proxy.Proto) (srvName string
 			}
 
 			srvName = host
+			from = "host header"
 		}
 	case proxy.ProtoQUIC:
 		qConn := pctx.QUICConnection
@@ -183,5 +187,7 @@ func clientServerName(pctx *proxy.DNSContext, proto proxy.Proto) (srvName string
 		srvName = tc.ConnectionState().ServerName
 	}
 
+	log.Debug("dnsforward: got client server name %q from %s", srvName, from)
+
 	return srvName, nil
 }