package/wprobe/src/filter/gen_filter.pl

   1 #!/usr/bin/perl
   2 use strict;
   3
   4 # helpers for custom packet format
   5 # bytes 0-7 are used by a dummy radiotap header
   6 my $WLAN_LEN = "radio[8:2]";
   7 my $SNR = "radio[10:1]";
   8 my $DEFAULT = undef;
   9
  10 my $MAGIC = "WPFF";
  11 my $VERSION = 1; # filter binary format version
  12 my $HDRLEN = 3; # assumed storage space for custom fields
  13
  14 my $output = "filter.bin";
  15 my $config = {
  16         "packetsize" => [
  17                 [ "small", "$WLAN_LEN < 250" ],
  18                 [ "medium", "$WLAN_LEN < 800" ],
  19                 [ "big", $DEFAULT ],
  20         ],
  21         "snr" => [
  22                 [ "low", "$SNR < 10" ],
  23                 [ "medium", "$SNR < 20" ],
  24                 [ "high", $DEFAULT ],
  25         ],
  26         "type" => [
  27                 [ "beacon", "type mgt subtype beacon" ],
  28                 [ "data", "type data subtype data" ],
  29                 [ "qosdata", "type data subtype qos-data" ],
  30                 [ "other", "$DEFAULT" ]
  31         ]
  32 };
  33
  34 sub escape_q($) {
  35         my $str = shift;
  36         $str =~ s/'/'\\''/g;
  37         return $str;
  38 }
  39
  40 my $GROUPS = scalar(keys %$config);
  41 open OUTPUT, ">$output" or die "Cannot open output file: $!\n";
  42 print OUTPUT pack("a4CCn", $MAGIC, $VERSION, $HDRLEN, $GROUPS);
  43
  44 foreach my $groupname (keys %$config) {
  45         my $default = 0;
  46         my $group = $config->{$groupname};
  47         print OUTPUT pack("a32N", $groupname, scalar(@$group));
  48         foreach my $filter (@$group) {
  49                 if (!$filter->[1]) {
  50                         $default > 0 and print "Cannot add more than one default filter per group: $groupname -> ".$filter->[0]."\n";
  51                         print OUTPUT pack("a32N", $filter->[0], 0);
  52                         $default++;
  53                 } else {
  54                         open FILTER, "./pfc '".escape_q($filter->[0])."' '".escape_q($filter->[1])."' |"
  55                                 or die "Failed to run filter command for '".$filter->[0]."': $!\n";
  56                         while (<FILTER>) {
  57                                 print OUTPUT $_;
  58                         }
  59                         close FILTER;
  60                         $? and die "Filter '".$filter->[0]."' did not compile.\n";
  61                 }
  62         }
  63 }