File Coverage

File:C4/SIP/Sip/Checksum.pm
Coverage:97.1%

linestmtbrancondsubtimecode
1package Sip::Checksum;
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use Exporter;
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use strict;
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use warnings;
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7our @ISA = qw(Exporter);
8our @EXPORT_OK = qw(checksum verify_cksum);
9our $debug = 0;
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11sub checksum {
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    my $pkt = shift;
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    return (-unpack('%16C*', $pkt) & 0xFFFF);
14}
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16sub verify_cksum {
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    my $pkt = shift;
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    my $cksum;
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    my $shortsum;
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        if ($pkt =~ /AZ(....)$/) {
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                $debug and warn "verify_cksum: sum ($1) detected";
23        } else {
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                warn "verify_cksum: no sum detected";
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                return 0; # No checksum at end
26        }
27    # return 0 if (substr($pkt, -6, 2) ne "AZ");
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29    # Convert the checksum back to hex and calculate the sum of the
30    # pack without the checksum.
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    $cksum = hex($1);
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    $shortsum = unpack("%16C*", substr($pkt, 0, -4));
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34    # The checksum is valid if the hex sum, plus the checksum of the
35    # base packet short when truncated to 16 bits.
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    return (($cksum + $shortsum) & 0xFFFF) == 0;
37}
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39{
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    no warnings qw(once);
41    eval join('',<main::DATA>) || die $@ unless caller();
42        # FIXME: what the heck is this?
43}
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451;