dist/ipf/test/vfycksum.pl

   1
   2 #
   3 # validate the IPv4 header checksum.
   4 # $bytes[] is an array of 16bit values, with $cnt elements in the array.
   5 #
   6 sub dump {
   7         print "\n";
   8         for ($i = 0; $i < $#bytes; $i++) {
   9                 printf "%04x ", $bytes[$i];
  10         }
  11         print "\n";
  12 }
  13
  14 sub dosum {
  15         local($seed) = $_[0];
  16         local($start) = $_[1];
  17         local($max) = $_[2];
  18         local($idx) = $start;
  19         local($lsum) = $seed;
  20
  21         for ($idx = $start, $lsum = $seed; $idx < $max; $idx++) {
  22                 $lsum += $bytes[$idx];
  23         }
  24         $lsum = ($lsum & 0xffff) + ($lsum >> 16);
  25         $lsum = ~$lsum & 0xffff;
  26         return $lsum;
  27 }
  28
  29 sub ipv4check {
  30         local($base) = $_[0];
  31         $hl = $bytes[$base] / 256;
  32         return if (($hl >> 4) != 4);    # IPv4 ?
  33         $hl &= 0xf;
  34         $hl <<= 1;                      # get the header length in 16bit words
  35
  36         $hs = &dosum(0, $base, $base + $hl);
  37         $osum = $bytes[$base + 5];
  38
  39         if ($hs != 0) {
  40                 $bytes[$base + 5] = 0;
  41                 $hs2 = &dosum(0, $base, $base + $hl);
  42                 $bytes[$base + 5] = $osum;
  43                 printf " IP: ($hl,%x) %x != %x", $hs, $osum, $hs2;
  44         } else {
  45                 print " IP($base): ok ";
  46         }
  47
  48         #
  49         # Recognise TCP & UDP and calculate checksums for each of these.
  50         #
  51         if (($bytes[$base + 4] & 0xff) == 6) {
  52                 &tcpcheck($base);
  53         }
  54
  55         if (($bytes[$base + 4] & 0xff) == 17) {
  56                 &udpcheck($base);
  57         }
  58
  59         if (($bytes[$base + 4] & 0xff) == 1) {
  60                 &icmpcheck($base);
  61         }
  62         if ($base == 0) {
  63                 print "\n";
  64         }
  65 }
  66
  67 sub tcpcheck {
  68         local($base) = $_[0];
  69         local($hl) = $bytes[$base] / 256;
  70         return if (($hl >> 4) != 4);
  71         return if ($bytes[$base + 3] & 0x1fff);
  72         $hl &= 0xf;
  73         $hl <<= 1;
  74
  75         local($hs2);
  76         local($hs) = 6; # TCP
  77         local($len) = $bytes[$base + 1] - ($hl << 1);
  78         $hs += $len;
  79         $hs += $bytes[$base + 6];       # source address
  80         $hs += $bytes[$base + 7];
  81         $hs += $bytes[$base + 8];       # destination address
  82         $hs += $bytes[$base + 9];
  83         local($tcpsum) = $hs;
  84
  85         local($thl) = $bytes[$base + $hl + 6] >> 8;
  86         $thl &= 0xf0;
  87         $thl >>= 2;
  88
  89         $x = $bytes[$base + 1];
  90         $y = ($cnt - $base) * 2;
  91         $z = 0;
  92         if ($bytes[$base + 1] > ($cnt - $base) * 2) {
  93                 print "[cnt=$cnt base=$base]";
  94                 $x = $bytes[$base + 1];
  95                 $y = ($cnt - $base) * 2;
  96                 $z = 1;
  97         } elsif (($cnt - $base) * 2 < $hl + 20) {
  98                 $x = ($cnt - $base) * 2;
  99                 $y = $hl + 20;
 100                 $z = 2;
 101         } elsif (($cnt - $base) * 2 < $hl + $thl) {
 102                 $x = ($cnt - $base) * 2;
 103                 $y = $hl + $thl;
 104                 $z = 3;
 105         } elsif ($len < $thl) {
 106                 $x = ($cnt - $base) * 2;
 107                 $y = $len;
 108                 $z = 4;
 109         }
 110
 111         if ($z) {
 112                 print " TCP: missing data($x $y $z) $hl";
 113 #               &dump();
 114                 return;
 115         }
 116
 117         local($tcpat) = $base + $hl;
 118         $hs = &dosum($tcpsum, $tcpat, $cnt);
 119         if ($hs != 0) {
 120                 local($osum) = $bytes[$tcpat + 8];
 121                 $bytes[$base + $hl + 8] = 0;
 122                 $hs2 = &dosum($tcpsum, $tcpat, $cnt);
 123                 $bytes[$tcpat + 8] = $osum;
 124                 printf " TCP: (%x) %x != %x", $hs, $osum, $hs2;
 125         } else {
 126                 print " TCP: ok ($x $y)";
 127         }
 128 }
 129
 130 sub udpcheck {
 131         local($base) = $_[0];
 132         local($hl) = $bytes[0] / 256;
 133         return if (($hl >> 4) != 4);
 134         return if ($bytes[3] & 0x1fff);
 135         $hl &= 0xf;
 136         $hl <<= 1;
 137
 138         local($hs2);
 139         local($hs) = 17;        # UDP
 140         local($len) = $bytes[$base + 1] - ($hl << 1);
 141         $hs += $len;
 142         $hs += $bytes[$base + 6];       # source address
 143         $hs += $bytes[$base + 7];
 144         $hs += $bytes[$base + 8];       # destination address
 145         $hs += $bytes[$base + 9];
 146         local($udpsum) = $hs;
 147
 148         if ($bytes[$base + 1] > ($cnt - $base) * 2) {
 149                 print " UDP: missing data(1)";
 150                 return;
 151         } elsif ($bytes[$base + 1] < ($hl << 1) + 8) {
 152                 print " UDP: missing data(2)";
 153                 return;
 154         } elsif (($cnt - $base) * 2 < ($hl << 1) + 8) {
 155                 print " UDP: missing data(3)";
 156                 return;
 157         }
 158
 159         local($udpat) = $base + $hl;
 160         $hs = &dosum($udpsum, $udpat, $cnt);
 161         local($osum) = $bytes[$udpat + 3];
 162
 163         #
 164         # It is valid for UDP packets to have a 0 checksum field.
 165         # If it is 0, then display what it would otherwise be.
 166         #
 167         if ($osum == 0) {
 168                 printf " UDP: => %x", $hs;
 169         } elsif ($hs != 0) {
 170                 $bytes[$udpat + 3] = 0;
 171                 $hs2 = &dosum($udpsum, $udpat, $cnt);
 172                 $bytes[$udpat + 3] = $osum;
 173                 printf " UDP: (%x) %x != %x", $hs, $osum, $hs2;
 174         } else {
 175                 print " UDP: ok";
 176         }
 177 }
 178
 179 sub icmpcheck {
 180         local($base) = $_[0];
 181         local($hl) = $bytes[$base + 0] / 256;
 182         return if (($hl >> 4) != 4);
 183         return if ($bytes[3] & 0x1fff);
 184         $hl &= 0xf;
 185         $hl <<= 1;
 186
 187         local($hs);
 188         local($hs2);
 189
 190         local($len) = $bytes[$base + 1] - ($hl << 1);
 191
 192         if ($bytes[$base + 1] > ($cnt - $base) * 2) {
 193                 print " ICMP: missing data(1)";
 194                 return;
 195         } elsif ($bytes[$base + 1] < ($hl << 1) + 8) {
 196                 print " ICMP: missing data(2)";
 197                 return;
 198         } elsif (($cnt - $base) * 2 < ($hl << 1) + 8) {
 199                 print " ICMP: missing data(3)";
 200                 return;
 201         }
 202
 203         local($osum) = $bytes[$base + $hl + 1];
 204         $bytes[$base + $hl + 1] = 0;
 205         $hs2 = &dosum(0, $base + $hl, $cnt);
 206         $bytes[$base + $hl + 1] = $osum;
 207
 208         if ($osum != $hs2) {
 209                 printf " ICMP: (%x) %x != %x", $hs, $osum, $hs2;
 210         } else {
 211                 print " ICMP: ok";
 212         }
 213         if ($base == 0) {
 214                 $type = $bytes[$hl] >> 8;
 215                 if ($type == 3 || $type == 4 || $type == 5 ||
 216                     $type == 11 || $type == 12) {
 217                         &ipv4check($hl + 4);
 218                 }
 219         }
 220 }
 221
 222 while ($#ARGV >= 0) {
 223         open(I, "$ARGV[0]") || die $!;
 224         print "--- $ARGV[0] ---\n";
 225         $multi = 0;
 226         while (<I>) {
 227                 chop;
 228                 s/#.*//g;
 229
 230                 #
 231                 # If the first non-comment, non-empty line of input starts
 232                 # with a '[', then allow the input to be a multi-line hex
 233                 # string, otherwise it has to be all on one line.
 234                 #
 235                 if (/^\[/) {
 236                         $multi=1;
 237                         s/^\[[^]]*\]//g;
 238
 239                 }
 240                 s/^ *//g;
 241                 if (length == 0) {
 242                         next if ($cnt == 0);
 243                         &ipv4check(0);
 244                         $cnt = 0;
 245                         $multi = 0;
 246                         next;
 247                 }
 248
 249                 #
 250                 # look for 16 bits, represented with leading 0's as required,
 251                 # in hex.
 252                 #
 253                 s/\t/ /g;
 254                 while (/^[0-9a-fA-F][0-9a-fA-F] [0-9a-fA-F][0-9a-fA-F] .*/) {
 255                         s/^([0-9a-fA-F][0-9a-fA-F]) ([0-9a-fA-F][0-9a-fA-F]) (.*)/$1$2 $3/;
 256                 }
 257                 while (/.* [0-9a-fA-F][0-9a-fA-F] [0-9a-fA-F][0-9a-fA-F] .*/) {
 258 $b=$_;
 259                         s/(.*?) ([0-9a-fA-F][0-9a-fA-F]) ([0-9a-fA-F][0-9a-fA-F]) (.*)/$1 $2$3 $4/g;
 260                 }
 261                 if (/.* [0-9a-fA-F][0-9a-fA-F] [0-9a-fA-F][0-9a-fA-F]/) {
 262 $b=$_;
 263                         s/(.*?) ([0-9a-fA-F][0-9a-fA-F]) ([0-9a-fA-F][0-9a-fA-F])/$1 $2$3/g;
 264                 }
 265                 while (/^[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F].*/) {
 266                         $x = $_;
 267                         $x =~ s/([0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]).*/$1/;
 268                         $x =~ s/ *//g;
 269                         $y = hex $x;
 270                         s/[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F] *(.*)/$1/;
 271                         $bytes[$cnt] = $y;
 272 #print "bytes[$cnt] = $x\n";
 273                         $cnt++;
 274                 }
 275
 276                 #
 277                 # Pick up stragler bytes.
 278                 #
 279                 if (/^[0-9a-fA-F][0-9a-fA-F]/) {
 280                         $y = hex $_;
 281                         $bytes[$cnt++] = $y * 256;
 282                 }
 283                 if ($multi == 0 && $cnt > 0) {
 284                         &ipv4check(0);
 285                         $cnt = 0;
 286                 }
 287         }
 288
 289         if ($cnt > 0) {
 290                 &ipv4check(0);
 291         }
 292         close(I);
 293         shift(@ARGV);
 294 }