UDP (User Datagram Protocol) datagram: Perl parsing library

UDP is a simple stateless transport layer (AKA OSI layer 4) protocol, one of the core Internet protocols. It provides source and destination ports, basic checksumming, but provides not guarantees of delivery, order of packets, or duplicate delivery.

KS implementation details

License: CC0-1.0

References

This page hosts a formal specification of UDP (User Datagram Protocol) datagram using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Perl source code to parse UDP (User Datagram Protocol) datagram

UdpDatagram.pm

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# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

use strict;
use warnings;
use IO::KaitaiStruct 0.009_000;

########################################################################
package UdpDatagram;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root || $self;;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{src_port} = $self->{_io}->read_u2be();
    $self->{dst_port} = $self->{_io}->read_u2be();
    $self->{length} = $self->{_io}->read_u2be();
    $self->{checksum} = $self->{_io}->read_u2be();
    $self->{body} = $self->{_io}->read_bytes(($self->length() - 8));
}

sub src_port {
    my ($self) = @_;
    return $self->{src_port};
}

sub dst_port {
    my ($self) = @_;
    return $self->{dst_port};
}

sub length {
    my ($self) = @_;
    return $self->{length};
}

sub checksum {
    my ($self) = @_;
    return $self->{checksum};
}

sub body {
    my ($self) = @_;
    return $self->{body};
}

1;