update and use rs/dnscache implementation instead of custom (#13348)

additionally optimize for IP only setups, avoid doing
unnecessary lookups if the Dial addr is an IP.

allow support for multiple listeners on same socket,
this is mainly meant for future purposes.

internal/http/server.go

@@ -18,6 +18,7 @@
 package http
 
 import (
+	"context"
 	"crypto/tls"
 	"errors"
 	"io/ioutil"
@@ -29,7 +30,6 @@ import (
 
 	humanize "github.com/dustin/go-humanize"
 
-	"github.com/minio/minio-go/v7/pkg/set"
 	"github.com/minio/minio/internal/config"
 	"github.com/minio/minio/internal/config/api"
 	"github.com/minio/minio/internal/fips"
@@ -64,7 +64,7 @@ func (srv *Server) GetRequestCount() int {
 }
 
 // Start - start HTTP server
-func (srv *Server) Start() (err error) {
+func (srv *Server) Start(ctx context.Context) (err error) {
 	// Take a copy of server fields.
 	var tlsConfig *tls.Config
 	if srv.TLSConfig != nil {
@@ -72,12 +72,11 @@ func (srv *Server) Start() (err error) {
 	}
 	handler := srv.Handler // if srv.Handler holds non-synced state -> possible data race
 
-	addrs := set.CreateStringSet(srv.Addrs...).ToSlice() // copy and remove duplicates
-
 	// Create new HTTP listener.
 	var listener *httpListener
 	listener, err = newHTTPListener(
-		addrs,
+		ctx,
+		srv.Addrs,
 	)
 	if err != nil {
 		return err