src/util/proxy_protocol_client.pl

   1 #!/usr/bin/perl
   2 #
   3 # Copyright (C) 2014 Todd Lyons
   4 # License GPLv2: GNU GPL version 2
   5 # <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>
   6 #
   7 # This script emulates a proxy which uses Proxy Protocol to communicate
   8 # to a backend server.  It should be run from an IP which is configured
   9 # to be a Proxy Protocol connection (or not, if you are testing error
  10 # scenarios) because Proxy Protocol specs require not to fall back to a
  11 # non-proxied mode.
  12 #
  13 # The script is interactive, so when you run it, you are expected to
  14 # perform whatever conversation is required for the protocol being
  15 # tested.  It uses STDIN/STDOUT, so you can also pipe output to/from the
  16 # script.  It was originally written to test Exim's Proxy Protocol
  17 # code, and it could be tested like this:
  18 #
  19 # swaks --pipe 'perl proxy_protocol_client.pl --server-ip
  20 #   host.internal.lan' --from user@example.com --to user@example.net
  21 #
  22 use strict;
  23 use warnings;
  24 BEGIN { pop @INC if $INC[-1] eq '.' };
  25 use IO::Select;
  26 use IO::Socket;
  27 use Getopt::Long;
  28 use Data::Dumper;
  29
  30 my %opts;
  31 GetOptions( \%opts,
  32   'help',
  33   '6|ipv6',
  34   'dest-ip:s',
  35   'dest-port:i',
  36   'source-ip:s',
  37   'source-port:i',
  38   'server-ip:s',
  39   'server-port:i',
  40   'version:i'
  41 );
  42 &usage() if ($opts{help} || !$opts{'server-ip'});
  43
  44 my ($dest_ip,$source_ip,$dest_port,$source_port);
  45 my %socket_map;
  46 my $status_line = "Testing Proxy Protocol Version " .
  47                   ($opts{version} ? $opts{version} : '2') .
  48                   ":\n";
  49
  50 # All ip's and ports are in network byte order in version 2 mode, but are
  51 # simple strings when in version 1 mode.  The binary_pack_*() functions
  52 # return the required data for the Proxy Protocol version being used.
  53
  54 # Use provided source or fall back to www.mrball.net
  55 $source_ip   = $opts{'source-ip'} ?  binary_pack_ip($opts{'source-ip'}) :
  56                  $opts{6} ?
  57                  binary_pack_ip("2001:470:d:367::50") :
  58                  binary_pack_ip("208.89.139.252");
  59 $source_port = $opts{'source-port'} ?
  60                  binary_pack_port($opts{'source-port'}) :
  61                  binary_pack_port(43118);
  62
  63 $status_line .= "-> " if (!$opts{version} || $opts{version} == 2);
  64
  65 # Use provided dest or fall back to mail.exim.org
  66 $dest_ip   = $opts{'dest-ip'} ?  binary_pack_ip($opts{'dest-ip'}) :
  67                $opts{6} ?
  68                binary_pack_ip("2001:630:212:8:204:23ff:fed6:b664") :
  69                binary_pack_ip("131.111.8.192");
  70 $dest_port = $opts{'dest-port'} ?
  71                binary_pack_port($opts{'dest-port'}) :
  72                binary_pack_port(25);
  73
  74 # The IP and port of the Proxy Protocol backend real server being tested,
  75 # don't binary pack it.
  76 my $server_ip   = $opts{'server-ip'};
  77 my $server_port = $opts{'server-port'} ? $opts{'server-port'} : 25;
  78
  79 my $s = IO::Select->new(); # for socket polling
  80
  81 sub generate_preamble {
  82   my @preamble;
  83   if (!$opts{version} || $opts{version} == 2) {
  84     @preamble = (
  85       "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A", # 12 byte v2 header
  86       "\x21",                                             # top 4 bits declares v2
  87                                                           # bottom 4 bits is command
  88       $opts{6} ? "\x21" : "\x11",                         # inet6/4 and TCP (stream)
  89       $opts{6} ? "\x00\x24" : "\x00\x0b",                 # 36 bytes / 12 bytes
  90       $source_ip,
  91       $dest_ip,
  92       $source_port,
  93       $dest_port
  94     );
  95   }
  96   else {
  97     @preamble = (
  98       "PROXY", " ",                                       # Request proxy mode
  99       $opts{6} ? "TCP6" : "TCP4", " ",                    # inet6/4 and TCP (stream)
 100       $source_ip, " ",
 101       $dest_ip, " ",
 102       $source_port, " ",
 103       $dest_port,
 104       "\x0d\x0a"
 105     );
 106     $status_line .= join "", @preamble;
 107   }
 108   print "\n", $status_line, "\n";
 109   print "\n" if (!$opts{version} || $opts{version} == 2);
 110   return @preamble;
 111 }
 112
 113 sub binary_pack_port {
 114   my $port = shift();
 115   if ($opts{version} && $opts{version} == 1) {
 116     return $port
 117       if ($port && $port =~ /^\d+$/ && $port > 0 && $port < 65536);
 118     die "Not a valid port: $port";
 119   }
 120   $status_line .= $port." ";
 121   $port = pack "S", $port;
 122   return $port;
 123 }
 124
 125 sub binary_pack_ip {
 126   my $ip = shift();
 127   if ( $ip =~ m/\./ && !$opts{6}) {
 128     if (IP4_valid($ip)) {
 129       return $ip if ($opts{version} && $opts{version} == 1);
 130       $status_line .= $ip.":";
 131       $ip = pack "C*", split /\./, $ip;
 132     }
 133     else { die "Invalid IPv4: $ip"; }
 134   }
 135   elsif ($ip =~ m/:/ && $opts{6}) {
 136     $ip = pad_ipv6($ip);
 137     if (IP6_valid($ip)) {
 138       return $ip if ($opts{version} && $opts{version} == 1);
 139       $status_line .= $ip.":";
 140       $ip = pack "S>*", map hex, split /:/, $ip;
 141     }
 142     else { die "Invalid IPv6: $ip"; }
 143   }
 144   else { die "Mismatching IP families passed: $ip"; }
 145   return $ip;
 146 }
 147
 148 sub pad_ipv6 {
 149   my $ip = shift();
 150   my @ip = split /:/, $ip;
 151   my $segments = scalar @ip;
 152   return $ip if ($segments == 8);
 153   $ip = "";
 154   for (my $count=1; $count <= $segments; $count++) {
 155     my $block = $ip[$count-1];
 156     if ($block) {
 157       $ip .= $block;
 158       $ip .= ":" unless $count == $segments;
 159     }
 160     elsif ($count == 1) {
 161       # Somebody passed us ::1, fix it, but it's not really valid
 162       $ip = "0:";
 163     }
 164     else {
 165       $ip .= join ":", map "0", 0..(8-$segments);
 166       $ip .= ":";
 167     }
 168   }
 169   return $ip;
 170 }
 171
 172 sub IP6_valid {
 173   my $ip = shift;
 174   $ip = lc($ip);
 175   return 0 unless ($ip =~ /^[0-9a-f:]+$/);
 176   my @ip = split /:/, $ip;
 177   return 0 if (scalar @ip != 8);
 178   return 1;
 179 }
 180
 181 sub IP4_valid {
 182   my $ip = shift;
 183   $ip =~ /^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/;
 184   foreach ($1,$2,$3,$4){
 185     if ($_  <256 && $_ >0) {next;}
 186     return 0;
 187   }
 188   return 1;
 189 }
 190
 191 sub go_interactive {
 192   my $continue = 1;
 193   while($continue) {
 194     # Check for input on both ends, recheck every 5 sec
 195     for my $socket ($s->can_read(5)) {
 196       my $remote = $socket_map{$socket};
 197       my $buffer;
 198       my $read = $socket->sysread($buffer, 4096);
 199       if ($read) {
 200         $remote->syswrite($buffer);
 201       }
 202       else {
 203         $continue = 0;
 204       }
 205     }
 206   }
 207 }
 208
 209 sub connect_stdin_to_proxy {
 210   my $sock = new IO::Socket::INET(
 211                PeerAddr => $server_ip,
 212                PeerPort => $server_port,
 213                Proto    => 'tcp'
 214              );
 215
 216   die "Could not create socket: $!\n" unless $sock;
 217   # Add sockets to the Select group
 218   $s->add(\*STDIN);
 219   $s->add($sock);
 220   # Tie the sockets together using this hash
 221   $socket_map{\*STDIN} = $sock;
 222   $socket_map{$sock} = \*STDOUT;
 223   return $sock;
 224 }
 225
 226 sub usage {
 227   chomp(my $prog = `basename $0`);
 228   print <<EOF;
 229 Usage: $prog [required] [optional]
 230   Required:
 231     --server-ip   IP of server to test proxy configuration,
 232                   a hostname is ok, but for only this setting
 233   Optional:
 234     --server-port Port server is listening on (default 25)
 235     --6           IPv6 source/dest (default IPv4), if none specified,
 236                   some default, reverse resolvable IP's are used for
 237                   the source and dest ip/port
 238     --dest-ip     Public IP of the proxy server
 239     --dest-port   Port of public IP of proxy server
 240     --source-ip   IP connecting to the proxy server
 241     --source-port Port of IP connecting to the proxy server
 242     --help        This output
 243 EOF
 244   exit;
 245 }
 246
 247
 248 my $sock = connect_stdin_to_proxy();
 249 my @preamble = generate_preamble();
 250 print $sock @preamble;
 251 go_interactive();