Docs: note redefined macros for expansions

[exim.git] / src / util / proxy_protocol_client.pl

diff --git a/src/util/proxy_protocol_client.pl b/src/util/proxy_protocol_client.pl
index 7cfc13ddcf88c28f2d3004250b3c7f9325af8846..8253fc4ac1bbde8435ae7288c81d540f91ca6512 100644 (file)
--- a/src/util/proxy_protocol_client.pl
+++ b/src/util/proxy_protocol_client.pl
@@ -3,6 +3,7 @@
 # Copyright (C) 2014 Todd Lyons
 # License GPLv2: GNU GPL version 2
 # <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>
+# SPDX-License-Identifier: GPL-2.0-or-later
 #
 # This script emulates a proxy which uses Proxy Protocol to communicate
 # to a backend server.  It should be run from an IP which is configured
@@ -21,6 +22,7 @@
 #
 use strict;
 use warnings;
+BEGIN { pop @INC if $INC[-1] eq '.' };
 use IO::Select;
 use IO::Socket;
 use Getopt::Long;
@@ -82,10 +84,10 @@ sub generate_preamble {
   if (!$opts{version} || $opts{version} == 2) {
     @preamble = (
       "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A", # 12 byte v2 header
-      "\x02",                                             # declares v2
-      "\x01",                                             # connection is proxied
+      "\x21",                                             # top 4 bits declares v2
+                                                          # bottom 4 bits is command
       $opts{6} ? "\x21" : "\x11",                         # inet6/4 and TCP (stream)
-      $opts{6} ? "\x24" : "\x0b",                         # 36 bytes / 12 bytes
+      $opts{6} ? "\x00\x24" : "\x00\x0b",                 # 36 bytes / 12 bytes
       $source_ip,
       $dest_ip,
       $source_port,